Applied Geometry for Engineering Design [1 ed.]

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________________________________ Applied Geometry for Engineering Design

eAcademicBooks LLC Applied Geometry for Engineering Design by Craig L. Miller, PhD. Copyright © 2011 Craig L. Miller. All rights reserved.

Printed in the United States of America All rights reserved. No part of this book may be reproduced, stored in a retrieval system or transmitted in any form or by any means, without the prior written permission of the publisher. The use of this book in electronic form by the original purchaser is authorized.

The author(s) and publisher have made every effort in the preparation of this book to ensure the accuracy of the information. However, the information contained in this book is sold without warranty, either express or implied. Neither the author(s) or eAcademicBooks will be held liable for any damages caused or alleged to be caused either directly or indirectly by this book. Published by eAcademicBooks. 609 N. Philips, Kokomo, IN 46901 Author: Craig L. Miller, PhD. Editor: Laura A. Ballinger Cover Design: Jennisse Martinez

Publication History August 2011

First Edition

Trademarks All terms and references that are know to be trademarks to the author(s) and the publisher have been capitalized and acknowledged. However, eAcademicBooks cannot guarantee the accuracy of these trademarks.

Table of Contents 1 2 3 4 6 7 8 10 11 12 13

Significance and Applications Product Lifecycle Management (PLM) Computer-aided Design Geometry 5 Space Sketching Geometric Construction Projection Systems 9 Pictorial Representations Section Views Dimensioning and Tolerancing Geometric Dimensioning and Tolerancing (GDT) Working Drawings

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Product Representation and Visualization

Using this book This e-book is a customized on-line version of learning materials for the Fall 2011 semester of CGT 163 for Purdue University. The purchase of this e-book links individual students directly to self-grading questions, and other content that are an integral part of the grade received in this course. See your instructor and refer to the course syllabus for details. Following is a description of the major features of this e-book:

1. Interactive on line exercises and review questions: Each chapter contains terms and concepts that are coordinated with on line questions and exercises. The on line questions and exercises at the end of each chapter may be answered, used for review and submitted for a portion of the course grade. To access the end of chapter exercises, go to http://www.eacademicbooks.com/Homework.asp. There you will encounter a series of exercises that your instructor has assigned. After you complete each assignment, the system will grade your responses and provide you with feedback. At each step you will be given the option of having the scores reported only to yourself or to your instructor. The intent of this feature is to give you the opportunity to redo each assignment until you receive a satisfactory score, and then submit that score to your instructor for credit. Knowledge of these questions and exercises are crucial to preparing for midterm and final exams.

Preface

F

or of the author of this digital textbook education is a passion that has led me to a profession that I truly enjoy, engineering graphics, that is of major importance to not only engineering but all technical professions. I have experienced engineering graphics from various perspectives including that of a student, a teacher at the middle and high school levels, an educator in vocational adult education, an industrial trainer, and an educator at higher education levels. I have witnessed and participated in the transition from board drawings with traditional tools to enterprise wide global applications of three dimensional (3D) computer-aided design (CAD) in product lifecycle management (PLM) settings.

Although engineering graphics has made radical changes over the past 25 years the legacy information of over 100 years of traditional drawings still exists that engineers need to be able to visualize, read, interpret, and explain to other engineer is vital. Without the ability to visualize and understand the standard practices that were used to develop these legacy drawings you will not be a complete engineer who understands the graphical language that was and is used to design and represent products. The overall goal of this material is to allow you to use graphics in both your college and professional careers. To that end, this textbook utilizes both traditional techniques and cutting edge technology to allow you to gain experience and to advance your ability to visualize, create freehand sketches, and use CAD technology to design and create products. It incorporates examples from multiple software CAD packages to illustrate industry accepted standards used to model products. CAD is a tool based on graphical concepts; these concepts are common to all CAD packages used across varying industries. This text is unique in that it is not a CAD software specific workbook but rather it illustrates common practices used by today’s prevalent CAD packages. This textbook also uses web links to further define, illustrate, and give examples of graphical concepts and industry applications. In 1676 Isaac Newton wrote, “… if I have seen a little further it is by standing on the shoulders of Giants." My professional and educational career is a reflection of Newton’s

statement and I’m grateful to the following individuals for their mentorship, guidance, and caring which has enabled me to advance it. Mr. Turner and Mr. Bascomb of Troy High School (Ohio) who introduced me to and made me interested in technical graphics. At Bowling Green State University Dr. Ernest Ezell and Dr. Bill Coggin helped me develop my first graphics textbook in 1984. I did not realize at the time it was my first professional achievement leading to a career in higher education. At the Ohio State University Professors Bob Laure and Doug Frampton who taught me the basics of descriptive geometry and the true meaning of graphics visualization. At Purdue University Professors William Ross and Michael Gabel and Dr. Jon Duff who furthered my knowledge of graphics and how it allows students to advance their abilities with it. And a special recognition to Dr. Gary Bertoline who at both The Ohio State University and Purdue University has been and continues to be my mentor and confidant and who has given me more professional opportunities and personal and professional guidance than I ever knew existed. Also I have to give special recognition to Professor Richard Parkinson who during my tenure in the Department of Engineering Graphics at The Ohio State University taught me not only understand basic and advanced concepts of engineering graphics but just as importantly encouraged me to present it in a manner that makes it interesting and fun for students to learn. Professor Parkinson taught me the true meaning of “thinking three dimensional thoughts 24 hours a day.” And finally to all of the students that I have had the pleasure of teaching and helping them to learn graphical concepts and life’s experiences. To date I’m not too sure if they have learned more from me or taught me more than I was able to provide them. Family members have been very influential in both my personal and professional development. To my late mother Carolyn Miller who instilled in me and insisted that I understand the importance of education and the opportunities that it provides. To my father Lester Miller, Jr. who provided me the example of work ethic and who sparked my interest in all things mechanical, their importance, and the respect of them and the individuals who are involved in their development, maintenance, and disposal. To my sister Dr. Suzanne Miller-Kobalka who was and still is my mentor and one of my best friends and confidants. She is an example of how education and work ethic can bring you

farther than you expected. For my children Erika, Katelyn, and Roman for allowing me to learn the true importance of life and to realize that structure and balance are key fundamentals of a happy life. Finally, to my wife Sue who is my best friend and who has been by my side through good times and bad and who tries to keep me on the path of “straight and narrow”. I hope that this text and the classes related to it helps you to understand the importance of graphics for engineers and that it aids you in your professional development doing so in an interesting manner. I think that you will find that after reading and completing the applied problems in this text coupled with the course lectures associated with it, you will never view the world the same as you have done in the past. Always remember Professor Parkinson’s thought “to think three dimensional thoughts 24 hours a day” in both your personal and professional lives.

Thank you! Dr. Craig L. Miller

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6 Freehand Sketching OBJECTIVES 1. Explain the importance of freehand sketching as a communication tool for designers 2. Use pencils to develop freehand sketches 3. Choose paper on which to develop freehand sketches. 4. Use basic manipulative techniques to develop freehand 5. Use the four basic shapes to develop freehand sketches 6. Use the scaffolding technique to develop freehand sketches 7. Explain the importance of proportioning in freehand sketching 8. Draw a freehand sketch which explains an object or idea based on proper proportions and overall neatness

GENERAL INFORMATION A freehand sketch is a pictorial representation of an object drawn without the use of triangles and other straightedges. One of the basic skills you as a designer must have is the ability to make accurate freehand sketches. This is true because you must be able to communicate your ideas with various individuals. Many times ideas cannot be clearly expressed through the use of words, thus the need arises to represent an idea pictorially. For example, a person receiving directions to a party can usually more easily understand the directions if they are sketched out on a map rather than written.

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Although freehand sketching is primarily used as a means of communicating with others, it is a useful tool for communicating with yourself. If an idea comes to mind a sketch can record the idea. Although the idea may not be used at the time, at a later date the sketch may be retrieved and can help to stimulate your imagination into the development of alternative, innovative solutions to a problem. Freehand sketches can also be used as valuable tools to determine the strategy for solving a problem. Many possible solutions can be discarded at the outset by analyzing them through freehand sketches. The discarded ideas are not developed further, thus saving time arriving at the most appropriate solution to a problem. For ex. if you are working on a problem you may think of an idea and sketch it. Aft· considering the 1 imitations of the problem your idea may not be practical and you will reject it. Freehand sketching does not have to be done in an artistic fashion, but sketches should be given serious thought and be drawn quickly and neatly. If sketches are drawn in a sloppy and careless manner they will not be helpful for communicating ideas, for planning a solution to a problem, or for reviewing at a later date. The degree of accuracy a given sketch should possess will depend upon its use. If a sketch is used to present an idea quickly, it may not need much details On the other hand, if the sketch will be used to present important concepts or details, it should be drawn with more care. An effective sketch i s one which appropriately communicates an idea or concept to another person.

SKETCHING MATERIALS An object can be sketched with the use of a marking device and a surface upon which to sketch. The ideal sketch will be drawn with a pencil and high quality paper, but this does not exclude envelopes, napkins or other media. Ideas should be recorded with sketches before the mental image of them fades.

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The paper on which a sketch will be drawn can be either plain or lined (grid). Lined paper, either square or isometric, is especially helpful for the beginner (figure 6.1). With lined paper you will find it easier to proportion drawings and sketch straight lines. The sketch can then be traced on tracing paper if the lines are unwanted (figure 6.1). Because the sketching paper is not taped down, the designer has the ease of movement to different locations.

Figure 6.1 Different types of sketching papers.

Use a medium or soft (2B, F, etc., see page 23) pencil for sketching. The pencil should be sharpened to a conical point with the tip slightly rounded. The sharpness of the pencil lead will determine the line weight (see Figure 6.2).

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Figure 6.2 Properly Sharpened Pencils

The pencil should be loosely held about 1 1/2" to 2" from the point, so you can see the lines as they are drawn and allow greater movement of the pencil. By rotating the pencil as it is being pulled you keep the point sharp and the lines remain clear.

SKETCHING LINES Horizontal lines are sketched by marking off the end points of the line with dots to locate the position of the line (see Figure 6. 3). If you are sketching a long line, it is better to use several dots to keep the line straight (see Figure 6.3). The lines are sketched between the two points by pulling the pencil from left to right and always keeping your eye on the dot that you are sketching toward. Before you darken the line, correct the defects of any previous stroke. Once you have become proficient, the initial light lines may become unnecessary. NOTE: the direction may be reversed for left-handed individuals.

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Figure 6.3 Sketching horizontal lines.

Vertical lines are sketched by pulling your pencil downward from the top of the line (see Figure 6. 4). Inclined lines are sketched more easily if the pencil is pulled from left to right. NOTE: the direction may be reversed for left-handed individuals. It may be easier to turn your paper so that inclined or vertical lines are drawn as horizontal lines see Figure 6.4) .

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Figure 6.4 Sketching vertical and inclined lines.

SKETCHING IRREGULAR CURVES To sketch an irregular curve: 1) locate the points which represent the outline of the irregular curve, 2) sketch a series of arcs through the points to complete the irregular curve (see Figure 6. 5) .

Figure 6.5 Sketching vertical and inclined lines.

SKETCHING SQUARES To sketch a square: 1) draw horizontal and vertical center lines (see Figure 6. 6A), 2) space equal distances on both the vertical and horizontal center lines (see Figure 6. 6B), 3) sketch lightly, 4) darken the horizontal and vertical lines to form the square (see Figure 6. 6C). A similar procedure is used to sketch rectangles (see Figure 6. 6D).

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Applied Geometry for Engineering Design Figure 6.6 Sketching squares & rectangles.

SKETCHING CIRCLES To sketch a circle or an arc you can use any of the following methods.

Method 1: Sketch the circle in an enclosed square Lightly construct a square which is the same size as the diameter of the circle. Divide the square by bisecting all four sides with lines and connecting the corners with diagonal lines. Then sketch and darken the circle within the square (see Figure 6-7A).

Method 2: Sketch the circle using horizontal and vertical lines Mark the estimated radius of the circle on the horizontal and vertical center lines. Complete the circle by connecting the arcs with lines (see Figure 6. 7B).

Method 3: Sketch the circle using paper as a construction tool Estimate the radius of the circle and mark it on the edge of the paper. Use the paper as a guide to mark off as many points from the center as necessary to complete the drawing. This method is usually used to sketch large circles (see Figure 6. 7C).

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Figure 6.7 Sketching circles.

SKETCHING AN ELLIPSE To sketch an ellipse: 1) lightly construct a rectangle which corresponds to the major and minor diameter of the ellipse (see Figure 1.8A), 2) determine the midpoints of the sides of the rectangle and sketch the tangent arcs (see Figure 6.8, 3) complete the ellipse by connecting the arcs (see Figure 6.8C) .

Figure 6.8 sketching an ellipse.

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BASIC SHAPES IN SKETCHING Most objects can be reduced to one or all of the following basic shapes: cubes, cones, spheres or cylinders. The shapes are constructed by assembling the various types of lines and figures as described in the previous sections and then adding simple rendering (see Figure 6.9). Rendering is the addition of shading and shadows to a drawing to give it more realism. You should be able to recognize these shapes in all objects. If you can sketch these basic shapes using various angles and lines of intersections, you will be able to sketch almost any object (see Figure 6.10).

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Figure 6.9 Basic Shapes in sketching.

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Applied Geometry for Engineering Design

Figure 6.10 Application of the Basic shapes to sketch.

PROPERTIES IN SKETCHES The most important concept of freehand sketching is keeping the sketches drawn in proportion. No matter how well the details are shown on a sketch, if the proportions are not accurate the sketch will not represent the object correctly. "Scaffolding" is the technique used to develop properly proportioned freehand sketches. Like the scaffolding used in the construction of a building, the scaffolding of a sketch will be used to start the sketch and then will be removed. To develop a sketch using the scaffolding technique: 1) draw a rectangular cube that has the overall dimensions of height, width, and

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depth of the object (see Figure 6.11A), 2) divide the rectangular cube into smaller sections · which represent the major features of the object (see Figure 6.11B), 3) add the circular features (see Figure 6.11C), 4) complete the sketch by connecting and darkening all of is features (see Figure 6.11D).

Figure 6.11 Use of scaffolding technique

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SUMMARY Freehand sketching is one of the most important communication tools that you need to develop to become a successful designer. Through the use of freehand sketches you can save new and innovative ideas for future reference, for discussion or for review by others. Although freehand .sketches do net have to be artistic you need to develop skill at freehand sketching so that the sketches can be interpreted easily by anybody who uses them.

TECHNICAL TERMS 1.

Cone -a geometric solid that is constructed with lines and has a point at one end and an ellipse or circle at the opposite end.

2.

Construction line -a light line used to layout and develop drawings and sketches.

3.

Cube a rectangular geometric solid with six square surfaces .that is developed from lines.

4.

Cylinder -a geometric solid that is constructed with lines and has ellipses or circles at each end.

5.

Ellipse -circular plane figure with a major and minor axis.

6.

Freehand sketch - a drawing of an object or idea done without the use of instrument drawing techniques.

7.

Line weight - the thickness and density of a line.

8.

Major diameter - the diameter across the longest side of an ellipse.

9.

Miner diameter - the diameter across the shortest side of an ellipse.

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10. Rendering - the addition of shading and shadows to a drawing to give it mare realism. 11. Scaffolding - a construction technique used to propor-tion freehand sketches. 12. Sphere -a geometric solid developed from circles. 13. Tangent - an intersection of two figures or lines at one paint.

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ASSIGNMENT 6 .1 DIRECTIONS: Sketch each of the fallowing figures in the boxes provided to the right. The assignment grade will be based a paper drawing techniques and proportions. (Objectives 4, 6, 8)

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ASSIGNMENT 6

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Applied Geometry for Engineering Design

ASSIGNMENT 6 .2 DIRECTION: Sketch each of the following figures in the boxes provided to the right. The assignment grade will be baaed a proper drawing techniques and proportions. (Objectives 4, 6, 8)

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ASSIGNMENT 6

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Applied Geometry for Engineering Design

ASSIGNMENT 6 .3 DIRECTION: Sketch each of the following figures in the boxes provided to the right. The assignment grade will be baaed a proper drawing techniques and proportions. (Objectives 4, 6, 8)

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ASSIGNMENT 6

.4 DIRECTIONS: Resketch and render. The following figure bellow do not include construction lines. The sketch GRADE will be based on paper drawing

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ASSIGNMENT 6 techniques, use of the four basic shapes, proportions, and overall neatness. (Objectives 4, 5, 6, 8)

.5 DIRECTIONS: Resketch and render. The following figure bellow. Do not include construction lines. The sketch GRADE will be based on paper drawing techniques, use of the four basic shapes, proportions, and overall neatness. (Objectives 4, 5, 6, 8)

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7 Multiview Drawing OBJECTIVES At the conclusion of this unit you should be able to accomplish the following with a 70% accuracy 1.

explain the importance of mulitview drawing as a communication tool far designers

2.

explain the concept of multiview drawing through the use of the transparent box method

3.

explain the concept of projection plans

4.

use parallel projectors to develop mechanical drawings

5.

use the three principle planes orthographic projection to develop mechanical drawing 5.1 frontal 5.2 horizontal 5.3 profile

6.

use the six different view of a multiview drawing to develop mechanical drawing 6.1 front

Chapter 6 6.2 6.3 6.4 6.5 6.6 7.

Multiview Drawing

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top right side left side back bottom

use three-view drawing to describe the physical shape of an abject 7.1 front 7.2 top 7.3 right wide

8.

select the appropriate view(s) to describe the physical appearance of an object with the last amount of hidden lines 8.1 number of views 8.2 selecting of front view

9.

apply the concept of paint numbering to the development of mulitview drawings

10. identify the type of plane and line in multiview drawings 11. apply the use of standard lines to multiview drawings 12. apply the rules of line conventions to multiview drawings 13. use standard techniques governing intersecting and overlapping lines in multiview drawing 14. center a multi view drawing 15. develop a three view drawing (given an isometric of an object or idea) based on line quality, correct scale, positioning, centering, and overall neatness of the drawing

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General Information Many times pictorial drawings cannot give a full description of an object. Important details on a back, side or bottom surface may be hidden. A product cannot be manufactured without a completely detailed description of it. Because pictorial drawings usually cannot completely describe objects, the multiview drawing system is used to describe them. Multiview (mechanical drawing) is a system of representing three dimensional objects through the arrangement of separate two-dimensional views. These views are arranged in a standard manner, and the system used to construct them is called orthographic projection. If dimensions and specifications are noted on the multiview drawing, it is referred to as a working or detail drawing.

The Transparent Box One way to explain and remember orthographic projection is through the use of a transparent box. The six sides of the transparent box are all two dimensional. Each side will provide two dimensions (width, height, or depth) of the three dimensional box. The front and back sides of the box provide the dimensions of width and height. The two sides of the box provide the dimensions of height and depth. And the top and bottom sides of the box provide the dimensions of width and depth. Now rename the front and back, sides, and the top and bottom of the box and call them projection planes. The front and back sides of the box will now be called and located on what is called the frontal projection plane. The two sides of the transparent box will now be renamed and located on what is called the profile plane. The top and bottom sides of the transparent box will now be called and located on what is called the horizontal plane. In each case the planes will contain the same two dimensions as the sides of the box which they replaced (see Figure 7.1). Now imagine that an object is placed within the transparent box. As you look into the box from the front you will see the front of the object through the side of the transparent box. If you were to draw the outline of the object on the side of the box it would be the same as projecting the outline of the object onto the frontal plane. This would give you the width and height of the object on the two dimensional frontal plane. This could be done to the back side of the box by

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projecting it onto the frontal plane of the transparent box. Each side of the box could be projected in a similar manner. The sides of the object would be traced (or projected) onto the sides (profile projection plane) of the transparent box

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Applied Geometry for Engineering Design

Figure 7.1 The orthographic transparent box.

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and they would give you the dimensions of height and depth of the object. Finally, the top and bottom sides of the object could be traced (or projected) onto the top and bottom sides (horizontal plane) of the box and they would give you the dimensions of width and depth of the object (see Figure 7. 1). Now if the box is torn open and each side (or projection plane) is positioned on a flat surface, the different sides of the abject will describe all three dimensions of the object through separate two dimensional views. This is the basic concept of orthographic projection (sea Figure 7.1).

Projection Planes There are three principle planes in orthographic projection: the frontal, profile and horizontal. Each projection plane of an object contains two views of the object. The frontal projection plane describes an object as it would appear if it were viewed from the front or from the back. Thus if a view of an object is from the front or back it is projected on the frontal plane. If a top or bottom view of an object is given then these views are located on the horizontal planes. And if a right or left side view of an object is given then these views are projected onto the profile projection plane. Any view located on a principle plane is called a principle view. Each principle view of an object will show two dimensions of the object (see Figure 7.2).

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Applied Geometry for Engineering Design

Figure 7.2 The principle planes of orthographic projection.

Parallel Projection Each view of an object will be projected, with parallel projectors onto one of the principle projection planes. Parallel projection is the term given to the imaginary lines which are projected at ninety degrees from one side of an object and locate points on the imaginary projection plane. These points locate the outline of the object on the projection plane (see Figure 7.3).

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Figure 7.3 Parallel projectors.

The Frontal Plane The front and back views of an object are projected onto the frontal plane; they are described by the dimensions of width and height (see figure 7.4).

Figure 7.4 The frontal plane.

The Horizontal Plane The top and bottom views of an object are projected onto the horizontal plane. They are perpendicular to the frontal plane and are described by the dimensions of width and depth (see Figure 7 .5).

Figure 7.5 The horizontal plane.

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Applied Geometry for Engineering Design

The Profile Plane The right and left-side views of an object are projected onto the profile plane. They are perpendicular to both the frontal and horizontal planes, and are described by the dimensions of height and depth (see Figure 7. 6).

Figure 7.6 The horizontal plane.

The Six View Drawing The maximum number of views which can be located on the principle planes of an object is six. If you imagine an object located in the transparent box, there will be two views on the frontal plane, two views on the horizontal plane, and two views on the profile plane. When the transparent box is unfolded the top view will appear over the front view, the bottom view under the front view, the right-side view to the right of the front view, the left-side view to the left of the front view, and the back view to the left of the left-wide view. It is important that the views are located in this manner and that the projections from all views align both vertically and horizontally with the front view. This allows the dimensions of height, width, and depth to be shown commonly among the views, thus eliminating the need to repeat dimensions. This view arrangement is the standard arrangement used throughout much of the western world (see Figure 7. 7). This system of projection is ref erred to as 3rd angle projection. The system used in many European countries is called 1st angle projection and the arrangement of views may differ somewhat from the system presented here.

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Figure 7.7 The view drawing.

The Three view Drawing Although through the use of orthographic projection six views can be used to describe an object, most objects are commonly described through the use of the top, front, and right-side views. Many objects can be accurately described with three views since additional views will usually only duplicate information already supplied in one of the principle views ( see Figure 7. 8).

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Applied Geometry for Engineering Design

Figure 7.8 The three view drawing. Many times an object can be described more accurately by using the front, top, And left-side views. If a left-hand view will describe an object more clearly then the left-side view should be used (see Figure 7.9).

Figure 7.9 Use of the left-side view.

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Some objects may require either more or fewer than three views to properly describe them. If this is true than use the number of views needed to properly describe the object.

One and Two View Drawing Many objects can be described through the use of one or two view drawings. If two views completely describe an object than only use two views to describe the object. Cylindrical parts and parts with uniform thicknesses can be described by one view. However, the one view drawing must contain a note which describes the missing view or gives the thickness of the object (see Figure 7.10).

Figure 7.10 The one and two view drawings.

View Selection The criteria for selection of views in multiview drawing is based on the view which fully describes the object with the fewest number of hidden lines or shows the outside contour of the object in the most descriptive manner. This view will be used as the front view. All other views are than projected from the

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front view. In Figure 7.11 "A" would be used as the front view because it describes the outside contour of the object (see Figure 7.11).

Figure 7.11 Selection of the front view an object. The front, top, and side views are considered the standard views of many objects. A chair; for example, has a front, top, and side view which can be recognized by everyone. Thus the views describing the chair should properly correspond to the commonly recognized views of the chair (see Figure 7. 12).

Figure 7.12 View selection of a chair.

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Point Numbering If you are having trouble interpreting a multiview drawing of an object a method of numbering points on the object may be helpful in the visualization of it. Figure 7.13 is an example of point numbering. Each point is labeled on the isometric drawing. These points are then transferred to the multiview drawing.· The points which are closest to you (5 & 6 on the front view of Figure 7. 13) will be labeled on the outside of the multiview drawing. The paints which are farthest away from you (7 & 8 on the front view of Figure 7. 13) will be labeled on the inside of the multiview drawing (see Figure 7. 13).

Figure 7.13 Point Numbering.

Lines and Planes In multiview drawing a line can appear as a point, true length, or foreshortened. A plane can appear as an edge, true size, or foreshortened (see Figure 7.14).

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Applied Geometry for Engineering Design

Figure 7.14 Lines and planes in multiview drawing.

Standard Lines As mentioned in chapter two, different types of lines with varying line weights will represent various components of an object in multiview drawing. Depending on the paper, different leads are used to produce standard lines. Except for guidelines and construction lines which are drawn very light, all other lines are drawn black. Standard lines are Distinguished by their varying widths and configurations. Designers must know the difference between the standard lines and how to apply them to multiview drawings (see Figure 7. 15)

Object Lines Object lines are the most important lines on a multiview drawing. They represent the actual outline of an object. Object lines like all other lines except for construction lines and guidelines should be drawn to appear as black as ink. Their width (.5mm) should be consistent throughout the drawing (see Figure 7.15).

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Figure 7.15 Standard lines or the alphabet of lines.

Hidden Lines Hidden lines as their name implies represent surfaces which cannot be seen in·a view of an object but must be shown to represent the object completely. Hidden lines are drawn as short black dashes (118", 3mm) with a small break (1/16", 2mm) lef t between the dashes. Like object lines their width is .5mm (see Figure 7.15).

Center lines Center lines are used to locate the center paints for circles and to describe axes of symmetry. They are drawn as alternate long ( 3/4", 19mm to 1 1/2", 38mm) and short (1/8", 3mm) dashes. The space between the dashes should be 1/16" (2mm). When the center paint of a circle is described by center lines the short dashes are intersected. The line weight of center lines is 0.3mm (See Figure 7.15). Although object, hidden, and center lines are the most commonly used type of lines, you should be able to recognize and draw all the other standard lines. These are drawn as they should appear on a drawing in Figure 7.15.

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Applied Geometry for Engineering Design

Line conventions Line conventions are the rules which govern overlapping and intersecting lines in multiview drawing. If two lines are located in the same position on a multiview drawing, object lines will take precedence overall other lines. Hidden lines will take precedence over all other lines, followed by center lines if the lines in the same location (see Figure 7.16).

Figure 7.16 Line conventions in multiview drawing.

Intersecting lines It is common for lines to overlap and intersect each other in multiview drawings. When this occurs the overlapping and intersecting lines are drawn in a standard manner which is understood by all designers (see figure 7.17).

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Figure 7.17 Intersecting and overlapping lines techniques.

Centering a Multiview Drawing There are many ways to center a multiview drawing. Depending on the number of dimensions and notes needed to explain an object more space may be needed between the views of the drawing. The method explained here will leave equal distance between the front and side views horizontally and the front and top views vertically in a multiview drawing. To center the front and side views of a multiview drawing: 1) determine the horizontal drawing space between the border lines, 2) add the width from the front view to the depth of the side view, 3) subtract the combined distance of the front and side views as determined in step two from the drawing area between borders from step one, 4) divide t his number by three, 5) locate this distance in from either t he left or right hand border line. Use the same procedure to locate

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the bottom line of the front view or the top line of the top view. The intersection of vertical and horizontal centering lines will be the beginning point of construction for the multiview drawing (see Figure 7.18).

Figure 7.18 Centering a multiview drawing.

Summary A thorough understanding of orthographic projection and how to apply multiview drawing is essential to designers. Through the use of multiview drawing almost any object idea can be presented. But without the knowledge of how to properly use multiview drawings, the effectiveness of an idea or the description of an object may not be complete or expressed properly.

Technical terns 1. Frontal plane - the projection plane onto which the front and back views of an object are projected and describes the height and width of the object. 2. Horizontal plane - the projection plane onto which the top and bottom views of an object are projected and describes the width and depth of the object.

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3. Line conventions - rules which exist concerning overlapping and intersecting lines in multiview drawing. 4. Multiview drawing - a system of representing three dimensional objects through the arrangement of separate two dimensional views of the object. 5. Orthographic projection - the representation of an object with the use of various two dimensional views which are projected onto a projection plane with the use of parallel projectors. 6. Parallel projectors - imaginary lines which are drawn perpendicular to an object and locate a view of the object onto a projection plane. 7. Perpendicular – a line or plane which is located 90 degrees to another line or plane. 8. Profile plane - the projection plane onto which the right and left-side views of an object are projected and describes the height and depth of the object. 9. Projection - the concept of projecting or drawing one surface of an object onto a plane. 10. Projection plane - an imaginary plane or surface onto which a view of an object is drawn. 11. Six view drawing - an orthographic projection of an object which describes the object with the use of the front, top, right-side, left-side, back, and bottom views. 12. Standard lines - lines which are universal to the field of mechanical drawing, and represent various surfaces of objects. 13. Three view drawing - an orthographic projection of an object which typically describes the object with the use of a front, top, and side view. 14. Working drawing - a mechanical drawing which contains dimensions and specification notes.

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Assignment 5.1 DIRECTIONS: Place the letter from the surface of the object in the multiview drawing onto the corresponding circle on the isometric drawing. The assignment grade will be based upon the correct identification of the surfaces on the isometric drawing (objectives 3, 4, 5, 6, a, 10, & 11).

DIRECTIONS: Place the letter from the surface of the object in the isometric drawing onto the carrespand1ng circle on the multiview drawing. The assignment grade will be based upon the correct identification of the surfaces on multiview drawing (objectives 3, 4, 5, 6, 8, 10, & 11).

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Assignment 5.2 DIRECTIONS: Sketch in the missing lines needed to complete the three-view drawings. The assignment grate will be based upon correct completion of the multiview drawings (objectives 6, B, 10, & 11).

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Assignment 5.3 DIRECTIONS: Sketch the correct amount of views needed to completely describe the given objects. The assignment grade will be based upon correct view selection, proper projection techniques, use of standard lines, line conventions and rules governing intersecting and overlapping lines (objectives 5, 6, 7, 9, 10,

11, 12, 13, & 14).

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Assignment 5.4 DIRECTIONS: Select a scale and draw the following three view drawings by completing the missing view. The assignment grade will be based upon proper. Multiview drawing techniques, line quality, centering and overall neatness (objectives 6, 8, 10, 11, 12, 13, & 14).

Chapter 08 – Projection Systems Auxiliary Views Objectives At the conclusion of this unit you should be able to accomplish the following: 1. explain the importance of auxiliary view drawing as a communication tool for engineers. 2. develop primary auxiliary view drawings. 3. draw auxiliary view drawings of curved shapes 4. construct partial auxiliary view drawings. 5. draw an auxiliary view drawing of an object or idea based on line quality, correct scale, positioning, centering, correct auxiliary view drawing techniques, and overall neatness.

General Information Many times objects will contain inclined surfaces which do not lie on a principal plane of the object. When this occurs the inclined surface will not appear true size on any regular orthographic view of the object. The inclined surface will appear foreshortened or as a line thus giving a distorted or unclear view of the object. One way of eliminating the distorted view of the inclined surface is to develop an auxiliary view drawing of the object. An auxiliary view drawing of an object describes the inclined surface of the object in true size and shape on a non-principal plane (see Figure 8.1).

Figure 8.1 An Auxiliary View of an Inclined Plane The principal planes which describe an object are the front, horizontal, and profile planes. When a principal primary auxiliary view of an object is drawn it is projected onto a non-principal or auxiliary plane of the object. The auxiliary plane is drawn perpendicular to one of the principal planes of the object. Thus when a .principal auxiliary view of an object is drawn it is projected from one of the principal views of the object (see Figure 8.2).

Figure 8.2 Primary Auxiliary Views

Development of Auxiliary Views There are two methods in which an auxiliary view drawing of an object can be developed the foldingline method and the reference plane method. Both methods are presented here and you can use either method to develop an auxiliary view drawing of an object. The reference plane

method is usually used to develop auxiliary views for cylindrical objects. Auxiliary Views Projected From the top view When an inclined view of an object appears as an edge in the top view, the inclined surface is perpendicular to the horizontal plane, thus the inclined surface is projected on an auxiliary view which runs parallel to the top view, giving a truesize auxiliary view of the inclined surface. Drawing an Auxiliary View in the Top View Using the Folding-line Method Figure 8.3 gives an example of an auxiliary view of a plane of an object which is projected from the top view using the folding-line method. To draw an auxiliary view from the top view using the folding-line method: 1. draw fold line H-I which is parallel to the edge view of the inclined plane, NOTE I the line of sight of the auxiliary view is perpendicular to the edge view of the inclined surface, 2. draw fold line H-F between the front and tap views, 3. project the length of the auxiliary view from the edge view of the inclined surface in the top view, NOTE: the projection lines are parallel to the line of sight of the auxiliary view, 4. determine the height by measuring the distance from fold line H-F to the bottom of the front view and project this distance from fold line H-I to determine the height of the of the auxiliary view (see Figure 8.3).

Figure 8.3 Top Auxiliary View Using the Folding-line Method Auxiliary Views Projected From the Front View When an inclined view of an object appears as an edge in the front view, the inclined surface is perpendicular to the frontal plane, thus the inclined surface is projected on an auxiliary view which runs parallel to the front view, giving a true-size auxiliary view of the inclined surface of the object. Drawing an Auxiliary View in the Front View Using the Folding-line Method Figure 8.4 gives an example of an auxiliary view of an object which is projected from the front view using the reference-plane method. To draw an auxiliary view from the top view using the referenceplane method:

1. locate the reference plane at the bottom of the front view. NOTE: The reference plane can be placed in any location on the front view as long as it is perpendicular to the line of sight, 2. project the length of the auxiliary view from the edge of the inclined surface on the top view of the object. NOTE: The projection lines are parallel to the line of sight of the auxiliary view, 3. determine the height of the auxiliary by measuring up from the reference plane located on the front view to the top of the object in the front view, 4. transfer the height dimensions from the front view to the reference plane established in the auxiliary view to give the height of the auxiliary view, NOTE: the reference plane can be located at any desired distance from the top view as long as there is enough room to construct the auxiliary view, and the reference plane is located parallel to the edge of the inclined surface (see Figure 8.4).

Figure 8.4 Front Auxiliary View Using the Reference-Plane Method project the length of the auxiliary view from the edge of the inclined surface on the front view of the object, NOTE. the projection lines are parallel to the line of sight of the auxiliary view, determine the depth of the auxiliary view by measuring up from the reference plane located on the top view to the top of the object in the top view, transfer the depth dimensions found in the top view to the reference plane established in the auxiliary view to determine the depth of the auxiliary view, NOTE. The reference plane can be located at any desired distance from the front view as long as there is enough room to draw the auxiliary view, and the reference plane

is located parallel to the edge of the inclined surface of the object (see Figure 8.6). 2. Figure 8.6 Front Auxiliary View Using the Reference-plane Method Auxiliary Views Projected From a Side View When an inclined surface of an object appears as an edge in a side view, the inclined surface is perpendicular to the profile plane. Thus the inclined surface is projected on an auxiliary view-which runs parallel to the side view, giving a truesize auxiliary view of the inclined plane of the object.

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5. Constructing an Auxiliary View on a Side View Using the Folding Line Method Figure 8.7 is an example of an auxiliary view of an object which is projected from the right side of an object using the folding line method. To draw an auxiliary view of an object from the side view using the folding line method,

Summary When an object contains an inclined plane the inclined plane will appear foreshortened in a normal orthographic view. This can cause the drawing to become confusing and create the possibility for misinterpretation. Auxiliary view drawings are used to eliminate this problem. Through the use of auxiliary view drawings the foreshortened plane can be drawn true size and shape, thus making the drawing more clear and allow it to be dimensioned.

Technical Terms 1. Auxiliary view – an orthographic projection system which allows surfaces not located on a

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principal plane to be drawn true size and shape. Folding-line Method – the system of projecting an auxiliary view with the use of a reference line which runs parallel to the edge of the inclined surface. Foreshortened – a surface when projected through orthographic projection does not appear true size and shape on a normal orthographic view. Inclined surfaces – any surface which is is not located on a principal orthographic view. Non-principal plane – any plane which is not parallel to the horizontal, frontal, or profile planes of projection. Primary auxiliary view – an auxiliary view which is projected from a principal view of an object. Reference plane – the imaginary two dimensional plane which is used to measure different dimensions that develop auxiliary view drawings. Reference-plane method – the system of projecting an auxiliary view with the use of a reference plane which is located on one of the principal views and on the auxiliary view. Secondary auxiliary view - an auxiliary view which is projected from a primary auxiliary view.

Unit Quiz Directions: Answer the following questions by selecting the best response. 1. A(n) _________view is a projection, perpendicular to an inclined or oblique plane. a. section b. isometric c. front

d. auxiliary 2. The reference plane line from which distances are determined in the auxiliary view is __________ to the edge view of the inclined surface. a. parallel b. perpendicular c. foreshortened d. normal 3. Auxiliary views are used when? a. An object has a cutting plane line through one view. b. An object is too large to show all details in the principal view. c. An object has important details on planes not parallel to any principal plane of projection. d. An object has very complicated details that are important for the design.

4. The auxiliary view is projected from a view which shows the foreshortened plane as: a. true size and shape b. a plane c. an edge d. parallel 5. Planes represented true size and shape in auxiliary views would be __________on a principal view. a. foreshortened b. true size and shape c. true length d. normal 6. Partial auxiliary views are used more often than full auxiliary views because: a. it takes less time to draw a partial auxiliary view.

b. a full auxiliary is, often confusing to the viewer. c. a full auxiliary view takes up too much space on the drawing. d. all of the above. 7. A _________ auxiliary view drawing is projected from either the frontal, horizontal, or profile planes. a. secondary b. primary c. folding d. reference 8. An auxiliary view which is projected from the top view of an object gives what dimension? a. top to bottom b. left to right c. front to back d. none of the above 9. The line of sight for an auxiliary view drawing is located __________to the edge view of the inclined plane. a. parallel b. perpendicular c. inclined d. oblique

10. When an inclined plane of an object appears as an edge in the front view, it will be ___________ to the frontal plane. a. parallel b. perpendicular c. inclined d. oblique

Assignment 8.1 Directions: Sketch the missing auxiliary following views of the figure below. The grade will be based upon proper auxiliary drawing techniques SCALE: Proportional

Assignment 8.3 Directions: Sketch the missing auxiliary following views of the figure below. The grade will be based upon proper auxiliary drawing techniques SCALE: Proportional

Assignment 8.4 Directions: Sketch the missing auxiliary following views of the figure below. The grade will be based upon proper auxiliary drawing techniques SCALE: Proportional Assignment 8.2 Directions: Sketch the missing auxiliary following views of the figure below. The grade will be based upon proper auxiliary drawing techniques SCALE: Proportional

9 Pictorial Drawing OBJECTIVES • • • • • • • • • • •

Explain the importance of pictorial drawing as a communication tool for designers Explain the three different types of pictorial drawings Explain the three different types of oblique drawings Explain the three different types of perspective drawings Explain the three different type of axonometric drawings Explain the difference between isometric projection and isometric drawing Draw isometric and non isometric lines and plane Explain why isometric drawing is the most commonly use pictorial drawing system. Identify if hidden and center lines are needed on an isometric drawing Draw an ellipse on an isometric drawing using the four center ellipse method or ellipse templates Draw an isometric drawing of an object or idea based on line quality, correct scale, positioning, centering, and overall neatness of the drawing

GENERAL INFORMATION Pictorial drawings are drawings of objects, drawn as you would normally view them. The main advantage of pictorial drawings over other types of mechanical drawings is that they are an effective way in which an idea can be communicated to individuals who may not have had any previous experience with mechanical drawing concepts. Pictorial drawings are also referred to as technical illustrations and are widely used in periodicals instructional booklets and parts catalogs.

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This unit will briefly introduce the three common types of pictorials 1) oblique, 2) perspectives, and 3) axonometric. The chapter will focus in depth on isometric drawings a type of axonometric drawing, because it is the most commonly used pictorial drawing system.

PICTURE PLANE All pictorial drawings are drawn to appear as three dimensional objects. The pictorial drawings are drawn upon a picture plane , which is a two dimensional flat surface such as a piece of paper or glass. A good way of visualizing a picture plane is to look at an object through a window. The picture plane is the two dimensional surface upon which a picture of an object is drawn giving the object the visual effect of being three dimensional (see Figure 9.1).

Figure 9.1 Visualizing a picture plane.

OBLIQUE DRAWING There are three basic types of oblique drawing: 1) cavalier, 2) cabinet, and 3) general. The three types are common in that their front surface are drawn true size and shape, parallel to the picture plane, and the receding axis angles can be anywhere from 0 to 90 degree· The difference occurs in measurements made along the receding axis. The cavalier oblique is drawn true length along the receding axis, while cabinet oblique are drawn half the true length along the receding axis. The receding axis on general oblique can be drawn anywhere from full to half length (see Figure 9.2).

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Figure 9.2 Types of oblique drawings.

PERSPECTIVE DRAWING Perspective drawing is the most realistic type of pictorial drawing, giving a view which closely approximates what is normally seen by the human eye. A perspective drawing gives you the impression that you are looking down a set of railroad tracks. The railroad tracks appear to vanish into a point somewhere in the horizon. Perspective drawings also give you the impression that the drawn object is vanishing into a point on the horizon of the paper. Depending upon the number of vanishing points, perspectives can be classified as 1) one point 2) two point, or 3) three point. A one point perspective shows one surface true size and shape parallel to the picture plane just as in oblique projection. The remaining sides recede to a single vanishing point on the horizon (see Figure 9.3A). A two point perspective contains two vanishing points. All vertical lines remain vertical, and all horizontal lines recede to the two vanishing points (see Figure 9.38). A three point perspective contains three vanishing points. All lines converge at the three vanishing points and none of the planes is true size and shape (see Figure 4.3A).

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Figure 9.3 Types of perspective drawings.

AXONOMETRIC PROJECTION Axonometric projection is a three dimensional view of an object, in which the object is positioned so that it is at an angular location with the picture plane. If the object is projected forward to the picture plane the projections will be perpendicular to the picture plane. There are three different types of axonometric pictorials: 1) isometric 2) dimetric, and 3) trimetric. Isometric projection is an axonometric projection in which all three planes are equally foreshortened and are located shown 120 degrees apart (see Figure 9.4A). Dimetric projection is an axonometric projection in which two planes will be equally foreshortened and are separated by two equal angles (see Figure 9.4B). Trimetric projection is an axonometric projection in which none of the planes is equally foreshortened and none of the planes have equal angles between them (see Figure 9.4C).

Figure 9.4 Types of axonometric drawings.

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ISOMETRIC PROJECTION Isometric projection is a type of axonometric projection, which can be compared to a box that is placed so that the sides which form a corner make equal angles (120 degrees) with each other, and each side of the box is equally foreshortened. Isometric projection is accomplished by rotating a cube 45 degree around an imaginary vertical axis and tilting the cube (35 degrees 16 minutes) along an imaginary horizontal axis. At this position all three planes of the object make equal angles (120 degrees) with the picture plane. In isometric projection all planes will be foreshortened to 82% of their true size (see Figure 9.5).

Figure 9.5 Isometric projection.

ISOMETRIC DRAWING An isometric drawing is similar to an isometric projection except that the planes of the object are drawn true length. Through the use of isometric drawing, pictorials can be measured using standard scales (see Figure 9.6). We are thus drawing the object in isometric drawing a bit larger then it would actually appear to the eye, but the relative proportions remain the same. This will call for the use of a larger then normal 35 degree ellipse if a circle is to be drawn on the isometric surface. Ellipse templates designed for use with isometric drawings are usually labeled as such and are not normally used with other types of pictorial drawings.

Chapter 9

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The three axes which form the isometric drawing are located 120 degrees apart. These axes are referred to as isometric axes. Any line that runs parallel to any of the isometric axes is called an isometric line. Any line which does not run parallel to any of the isometric axes is called a nonisometric line. True measurements can only be made along isometric lines (see Figure 9.7). Nonisometric lines cannot be measured directly.

Figure 9.7 Location of the isometric axis. The three surfaces on an isometric cube are called isometric planes. Planes which are parallel to the isometric planes are called isometric planes. Nonisometric planes are planes which are not parallel to any of the isometric planes.

CONSTRUCTION OF AN ISOMETRIC DRAWING To construct an isometric drawing: 1) using your 30-60-90 degree triangle, construct the front isometric plane with the dimensions of width (W) and height (H). The width measurement is made on the 30 degree axis and the height measurement is made on the vertical axis. 2) Construct the horizontal isometric plane with the dimensions of width (W) and depth (D). The width dimension is made on the left 30 degree axis and the depth is made on the right 30 degree axis. 3) Construct the profile isometric plane with the dimensions of depth (D) and height (H). The depth dimension is made on the 30 degree axis and the height measurement is made on the vertical axis. 4) Complete the construction so that a constructed box is developed which contains the overall dimensions of the

7 Applied Geometry for Engineering Design object. This technique should be used for the development of all objects in isometric drawing (see Figure 9.8). Isometric grid paper can also be used to construct isometric drawings. The grid paper is lined with 30 degree and vertical lines (see Figure 9.9). The drawing can be developed on the grid paper and traced onto vellum or the grid paper can be placed under the vellum to develop the drawing directly on it.

Figure 9.8 Construction of an isometric drawing.

Figure 9.9 Isometric grid paper.

NONISOMETRIC LINES & PLANES Nonisometric lines and planes are located on a drawing by determining their endpoints. The endpoints must be found by measuring their location along the isometric lines· Once these points have been determined the nonisometric line or plane is drawn by connecting the measured points (see Figure 9.10).

DIFFERENT POSITIONS OF THE ISOMETRIC AXES

Chapter 9 Pictorial Drawing 8 Although the isometric drawing is usually drawn by using 30 degree receding axes, it can be placed in any position if this will describe the object better. But the angles between the axes must always be 120 degrees apart. The choice of the axis position is usually regulated according to how the object is normally viewed or by the position which describes the object the best (sees Figure 9.11).

Figure 9.10 Isometric & nonFigure 9.11 Different isometric isometric lines & planes. axis positions. Angular measurements cannot be made on isometric drawings, because the surfaces of isometrics are not true size. Angular measurements must be determined by using coordinates measure along isometric lines. This is the same procedure that was mentioned for nonisometric lines. The angles will either be greater or smaller on isometric drawings (See Figure 9. 12). Inclined surfaces cannot be measured on isometric drawings. Like angles, the endpoints of the inclined surface must be located along isometric lines (see Figure 9.13).

Figure 9.12 Angles in isometrics. isometrics

Figure 9.13 Inclined surfaces in

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HIDDEN LINES IN ISOMETRICS Hidden lines are used in isometric drawing only in cases where they are needed to make a drawing clear (see Figure 9.14).

Figure 9.14 Hidden and center lines in isometrics.

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CENTER LINES IN ISOMETRICS Center lines are used sparingly in isometric drawing. Only in cases where dimensions are needed or symmetry must be shown are center lines used (see Figure 9.14).

CIRCLES AND ARCS IN ISOMETRIC Circles can be developed through the use of the four center ellipse method. The diameter of the circle is used as a guide to construct a rhombus around the center lines of the circle. Perpendicular lines are then constructed from the intersection of the center lines and the sides of the rhombus to the corners of the rhombus. Using four different centers and two different radii the ellipse is constructed. The same procedure is used for construction of arcs except only half of the rhombus is constructed (see Figure 9.15).

Figure 9.15 The four center ellipse method. Circles and arcs can also be developed through the use of an ellipse template. The main advantage of on ellipse template is the reduction of time needed to draw the ellipse. To use the isometric ellipse template on the front isometric plane the minor diameter of the ellipse is aligned with the center line that runs parallel to the receding line of the profile plane. On the horizontal plane the minor axis of the ellipse is aligned with the canter line that runs parallel with the vertical line which separates the vertical axes between the front and profile planes· On the

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profile plane the minor axis is located by the canter line which runs parallel to the receding line of the front plane (see Figure 9. 16).

CURVES IN ISOMETRICS Curved surfaces in isometrics are located using the same procedure as was used to locate anoles and inclined surfaces. The curved surfaced ere determined by locating the coordinates of the curve along isometric lines (see Figure 9.17). The more points that are plotted, the more accurate the curved surface. The irregular curve is used to connect the paints.

Figure 9.16 Use of isometric Figure 9.17 Irregular curves in ellipse templates. isometrics.

CENTERING ISOMETRIC DRAWINGS To center an isometric drawing 1) locate the center of the drawing area with diagonals, 2) construct a vertical line from the center of the drawing area so that it is equal to 1/2 the height of the abject, 3) construct a 30 degree line down to the left from the end of the height line that is equal to 1/2 the depth, 4) construct a 30 degree down to the right from the and of the depth line that is

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equal to 1/2 the width, 3) start the isometric construction box at the and of the width line (see Figure 9.18)

Figure 9.18 Centering of an isometric drawing.

SUMMARY Many times you as the designer will develop a design which you will have to explain to other individuals. Some of these individuals will have had little if any experience with mechanical drawings. You will have to choose a drawing which can be easily understood by someone who has had little experience with mechanical drawings. Pictorial drawings are representations of objects as they are normally viewed, and should be used to explain designs to people with limited backgrounds in Mechanical drawing. TECHNICAL TERMS 1. Axonometric - a drawing that shows a three dimensional view of an object, and is positioned so that it is at an angular location with the picture plane. 2. Axis - the major lines of axonometric, perspective, and oblique drawings.

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3. Cabinet oblique – a pictorial drawing in which the front surface of half an object is drawn true size and is located parallel to the picture plane, and all receding axis are drawn half their true length. 4. Cavalier oblique - a pictorial drawing in which the front surface of an object is drawn true size and is located parallel to the picture plane, and all receding axis are drawn true length at 45 degree angles. 5. Dimetric drawing - an axonometric drawing in which two planes are equally foreshortened and are separated by two equal angles. 6. Frontal Plane - the plane of an object as it is viewed from the front. 7. General Oblique - a pictorial drawing in which the front surface of an object is drawn true size and is located parallel to the picture plane, and all receding axis are drawn anywhere from full to one half their true length. 8. Horizontal Plane - the plane of an object as it is viewed from the top. 9. Isometric Drawing - an axonometric projection in which an object is placed so that its axis makes equal angles with the plane of projection, and the axis are drawn true size with standard scales. 10. Isometric Grid Paper - paper with 30 degree receding lines which are used in the development of isometric drawings. 11. Isometric Projection - a type of axonometric projection in which an object is placed so that its axes make equal angles with the plane of projection, and all surfaces are foreshortened 18% of their true size. 12. Oblique - a pictorial drawing· system in which the front surface of an object will always appear true size and will run parallel to the projection plane. 13. One Point Perspective - a perspective drawing which shows one surface of an object true size and shape, parallel to the plane of projection, and all receding axis converging to a single vanishing point on the horizon.

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14. Perpendicular - a line or plane which is located 90 degrees to another line or plane. 15. Perspective Drawing - a drawing which uses vanishing paints, and gives a view which closely represents what is normally seen by the eye. 16. Pictorial Drawing – a represents an object type of mechanical drawing that in a three dimensional view. 17. Picture Plane - an imaginary plane or surface that an object is viewed through. 18. Profile Plane - the plane of an object as it would be viewed from the side. 19. Projection - the concept of projecting or drawing one surface of an object on to a plane. 20. Rhombus- a four sided geometric figure used in development of ellipses. 21. Three Point Perspective -a perspective drawing that shows the receding lines converging to three separate vanishing points. 22. Trimetric Drawing -a form of axonometric drawing in which none of the planes of an object are equally foreshortened and none of the planes has equal angles between them. 23. Two Point Perspective - a perspective drawing that has all horizontal lines converging to two separate vanishing points. 24. Vanishing Points - points where the receding axes of a perspective drawing converge.

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ASSIGNMENT 4.1A DIRECTION: Sketch each of the fallowing figures on the grid paper. The assignment Grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT

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ASSIGNMENT 4.1B DIRECTIONS: sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT

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ASSIGNMENT 4.1C DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT

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ASSIGNMENT 4.1D techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT 4.1E DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT 4.1F techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT 4.1G DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT 4.1H techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT 4.1I DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The assignment grade will be based on proper proportions and isometric drawing

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

4.1J assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

4.1K assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

Chapter 9

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

4.1L assignment grade will be based on proper proportions and isometric drawing techniques (objectives 7, 9, 10, & 11).

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ASSIGNMENT DIRECTIONS: Sketch each of the fallowing figures on the Grid paper. The

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ASSIGNMENT 4.2 DIRECTIONS: Using the given isometric axis, draw a three inch isometric cube. Center and draw two inch ellipses on each plane. The assignment grade will be based on proper line quality, scale, and isometric drawing techniques (Objectives 7, 10, & 11).

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ASSIGNMENT 4.3 D)RECT)ONS: Draw to a selected scale and canter on size A vellum the following six figures. The assignment grade will be based on proper line quality, scale, and use of isometric drawing techniques (objectives 7, 9, 10, & 11).

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10 SECTION VIEWS OBJECTIVES At the conclusion of this unit you should be able to accomplish the following with 70% accuracy: 1. explain the importance of section view representations as communication tools for designers 2. use the basic lines and terms to draw a sectional view drawing: a. 2.1 cutting plane lines b. 2.2 cross hatching lines 3. use the different types of sections to correctly describe an object: a. 3.1 full b. 3.2 half c. 3.3 offset d. 3.4 revolved e. 3.5 removed f. 3.6 broken 4. use conventional breaks to create a section view of a part. a. 4.1 unidirectional b. 4.2 aligned 5. use conventional revolutions to create a standard representation of a sectioned part. 6. draw a section view drawing of an object by applying correct sectioning techniques, so the sectioned drawing clearly and correctly describes the part

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GENERAL INFORMATION Many times an object may have many complicated interior and exterior parts. Through the use of multiview drawing the part can be fully described, but the multiview drawing may contain several hidden lines and be confusing to interpret. Any confusion caused by such a drawing could prove to be expensive to the producer. One way of eliminating hidden lines from a multiview drawing is to draw what is called a section view drawing. A section view drawing is a drawing of an object that shows the object cut into separate parts, with one portion removed and the remaining portion giving a cross section view of the, interior construction of the object. The object is cut into the separate parts by a cutting plane. Cutting planes are two dimensional planes like the frontal, profile, and horizontal projection planes used in multiview projection. Where they cut through the object can be compared to a knife passing through a tomato. The cutting plane like the knife passing through the tomato, cuts completely, through the object, dividing it into separate parts. One part of the object is removed, thus exposing the remaining portion as a section view. The location of the cutting plane is determined by the object being described: the cutting plane is placed where it would describe the object with the fewest hidden lines (see Figures 10.1a & b).

Figure 10.1a Standard multiview of a part

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Figure 10.1b Section multiview of the same part Cutting Plane Lines & Cross Hatch Lines Section view drawings are similar to multi view drawings in that they show separate two dimensional views of an object. The difference is that one view of the object is a section view that has been cut by a cutting plane, exposing the interior details of the object. The location where the cutting plane passes through an object must be shown on the mechanical drawing. This location is shown by a cutting plane line. There are two different types of cutting plane lines. They are drawn as black thick (.7mm) lines. The most common cutting plane line consists of alternate short (1/8", 3mm) and long (3/4", 20mm) lines. A second type consists of equal (1/4”, 6mm) dashes. Either type is acceptable. The ends of any cutting plane line have a 1/211 (13mm) line ended by an arrowhead which lies perpendicular to the rest of the cutting plane line. The arrowhead points in the direction of the line of sight of the section (see Figure 10.2).

Figure 10.2 Cutting Plane Lines When a section view of an object is drawn the object is cut by the cutting plane and the surfaces of it which are cut by the cutting plane must be represented on the mechanical drawing. Different symbols are used to

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describe different types of materials such as steels, concrete, wood, etc. (see Figure 10.3). However, because there are so many different types of materials the specific symbols are hard to remember and hard to distinguish. It is common practice to use the cast iron (general) symbol to represent the cut surfaces. If the cast iron (general) symbol is used and a special material needs to be distinguished, a specific section symbol and a note can be used to describe and locate the special material.

Figure 10.3 Cross Hatching Representations The cutting plane can be located on any view of an object as long as it describes the desired feature of the object with the fewest number of hidden features represented by dashed lines. In figure 10.4a the cutting plane, located by the cutting plane line, and is placed on the top view of the object. The front portion of the object is then removed exposing the back portion of the object as a section in the front view.

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Figure 10.4a Dividing a Part from Front to Back In figure 10.4b the cutting plane is placed horizontally through the front view of the object. The top portion of the object is then removed, exposing the bottom portion of it as a section view in the top view.

Figure 10.4b Dividing a Part from Top to Bottom

In Figure 10.4c the cutting plane is again located in the front view, but it divides the part into half from left to right. This exposes the right half of the part as a section view in the right side view.

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Figure 10.4c Dividing a Part from Top to Bottom You must draw the cast iron symbol, otherwise known as the general section line symbol, neatly and correctly. Section lines are drawn thinner than object lines, but they are drawn black. Section lines should be spaced evenly between 1/16"(1.5mm) to 1/8" (3mm) apart (see Figure 10.5). They should be drawn at 30, 45, or 60 degree angles unless this would cause them to run parallel or perpendicular to any object lines. If this occurs then draw the section lines at a different angle so they will not become confused with object lines (see Figure 10.6).

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Applied Geometry for Engineering Design Figure 8.5 Correct Spacing for the Cast Iron Cross Hatching (general) Symbol

Figure 8.6 Cross Hatching Representations Thin parts like sheet metal or washers are not cross hatched, but should be represented as solid black. Extremely large parts can be cross hatched by only cross hatching the outline of the part (see Figure 10.7).

Figure 10.7 Section Lining Thin and Large Parts If the object cut by the section line is composed of several component parts, such as an assembly drawing of a product, each component part must be distinguished from all others by the section lines or symbols. The section line for each component part will be drawn at a different angle from all other component parts so that they can be distinguished from each other. The section lines will run in the same direction for each component part, even if the component part is divided into separate parts or is drilled through (see Figure 10.8).

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Figure 10.8 Cross Hatching Different Parts of a Product Assembly

Line Rules for Sectioning All object lines and edges which are located behind the cutting plane must be shown, unless they would make the drawing confusing. If these lines were not drawn the object would appear in separate, unrelated parts (see Figure 10.9).

Figure 10.9 Object line Standards in Section Views The cross hatched area must always fall within an object line of the object. The section lined area can never fall within a hidden line because the surface of the object has been cut by the cutting plane, thus eliminating most of the hidden features represented by dashed lines. Because section view drawings are used to eliminate hidden lines, the hidden lines are usually not drawn on section view drawings. You should only use hidden lines in cases where they would make the drawing more clear (see Figure10.10).

Figure 10.10 Use of Dashed Lines in Section Views Cross Hatching Parts You should not cross hatch many standard component parts of a product. Bolts, nuts, rivets, shafts and set screws should not be section lined because

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they do not contain any interior features. Ribs and webs are support features for many cylindrical parts, and they should not be section lined if the cutting plane cuts through them in a flatwise direction. If they are section lined the part will be misleading. If the cutting plane cut through a rib or web and it describes the thickness of the web or rib, the rib or web must be cross hatched (see Figure 10.11).

Figure 11.11 Ribs and Webs in Section Views Full Sections All of the section view drawings which have been presented so far in this chapter have been full sections. A full section view of a part is a section view of the object where the cutting plane was passed completely through the object on one flat plane. You can compare this type of section view to a knife passing through a tomato. The cutting plane, like the knife passing through the tomato, cuts completely through the object, dividing it in half on a straight plane. One half of the abject is removed, thus exposing the remaining half of the abject as a section view. The line of sight of the section will be the same as the direction of the arrows on the cutting plane line (see Figure 10.12)

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Figure 10.12 Full Section View of a Part Half Sections Half-sections are most often used to describe cylinders and many symmetrical parts. A half section view of a part gives a .section view of half of a part. The cutting plane cuts halfway through the object and a quarter of the abject is removed (see Figure 10.13).

Figure 10.13 Half Section of a Part Offset Sections Offset sections are a form of full sections. The difference between full sections and offset sections lie in the placement of the cutting plane. As was discussed above, in a full .action the cutting plane is one flat plane which cuts the part in half. In an offset section the cutting plane is not one flat plane

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instead the cutting plane is turned perpendicularly to cut through all the important features of the part. The cutting plane will make perpendicular bends to expose all of the important features. The offset section will still appear as a full section in the section view (see Figure 10.14).

Figure 10.14 Offset Section View of a Part Revolved Sections A revolved section is section view of a portion of a part. They are drawn on the part thus eliminating the need to draw an entirely separate section view. Figure 10.15 illustrates the use of two different types of revolved sections. The revolved section can be placed within the view

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of the object through the use of conventional breaks. With cylindrical parts the revolved section can be superimposed upon the view of the abject (sea Figure 10.15).

Figure 10.15 Revolved Sections Views

Removed Sections A removed section is a farm of revolved .section in which the revolved section is placed separately or removed from the normal view. Removed sections are used when there is not enough room to use a revolved section on a normal view. Removed sections, space permitting, are placed near to the view where the section view was removed. Center lines are used to show where the removed section was rotated around and located on the normal view (see Figure 10.16).

Figure 10.16 Removed Sections Placed Adjacent to the View A removed section does not have to be located directly beside the view from which it was taken. Labeled cutting planes can be used to name and locate where the cutting plane passed through the part. The labeled section which corresponds to the labeled cutting plane will tell you where the .section was taken fr.om (see Figure. 10.17).

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Figure 10.17 Removed Section Labeled by the Cutting Plane ,. Broken Sections A broken section is a section view of portion of a part. The portion of the object which needs to be sectioned is exposed by tearing or breaking away a portion of the part with conventional break lines. Broken sections are used in cases where they will eliminate the need for a separate view of a portion of a part (see Figure 10.18).

Figure 10.18 Broken Section

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Conventional Revolutions Many times cylindrical parts will have ribs, webs, or holes located symmetrically on them. When a rib, web, or hole is projected onto the rectangular view, the rib or web will appear foreshortened. Holes may appear distorted or located in the wrong location. To eliminate this problem the rib, web, or hole 'is rotated so that the cutting plane line cuts through it. This gives you a clearer description of the object (see Figure 10.19).

Figure 10.19 Conventional Revolutions Summary Section view drawings should be used to represent objects more clearly than what they would appear as a multiview drawing. There are several types (full, half, offset, revolved, removed, and broken-out) of section view drawings. The type of section view drawing chosen to represent the interior details of the object should be carefully determined so the drawing will not contain many hidden lines and be easy to understand. Technical Terms 1. Broken section - a section view drawing which uses conventional breaks to expose a sectioned interior view. 2. Cast iron (general) symbol - the sectioning symbol which is used to represent cast iron. It is the general section symbol which is used to represent all sectioned materials. 3. Component parts - individual parts of an object which combine to form a completed mechanism. 4. Conventional break lines - lines which are used to represent where a portion of a part has been broken and removed. 5. Conventional revolutions - the drawing technique which revolves ribs, webs, or holes so they will not appear foreshortened or misplaced when they are projected to a rectangular view.

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6. Cutting plane - two dimensional planes like the frontal, profile, and horizontal projection planes use with multiview drawing. They cut through a part and expose the desired interior features of a part or product. 7. Cutting plane line - the line used to locate the cutting plane. The arrows on cutting plane are the line of sight of the section. 8. Full section - a section view of an object where the cutting plane is passed completely through an object on one flat plane. One half of the object is removed, exposing the remaining section as a full section. 9. Half section a section view normally used with cylinders and symmetrical parts, where the cutting plane cuts halfway through the object and a quarter of the object is removed. 10. Offset section - is a form of full section in which the cutting plane is perpendicularly bent to pass through important features of the object. 11. Removed section - is a form of revolved section in which the revolved section is placed separately or removed from the normal view of the object. 12. Revolved section – is a section view of a portion of a part which has been rotated or revolved from its original position. 13. Ribs outside support features for cylindrical objects. 14. Section symbols - symbols used to represent different materials in section view drawing. 15. Section view drawing - a form of mechanical drawing in which a two dimensional cutting plane is passed through a part or product cutting it into separate pieces and exposing hidden features. 16. Standard component parts - component parts such as rivets, washers, nuts, and bolts. 17. Webs - inside support features for cylindrical parts. Unit Quiz Directions: Answer the following questions by selecting the best response. 1. A section view usually shows a. exterior b. interior c. profile d. foreshortened

details.

2. When a quarter of a part or product is removed. The section view is referred to as a(n): a. full section. b. half section. c. quarter section.

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d. offset section. 3. A cutting plane is: a. a heavy, solid, straight line. b. placed through the center of a part or product. c. an imaginary cut through a part or product. d. represents a hidden plane. 4. The viewing direction of a section view is indicted by the: a. viewing direction of the section view. b. arrows at the end of the cutting plane line. c. offset cutting plane in the section view. d. dashed lines on the section view. 5. The lines in a section view used to show where there material is cut, and in some cases to identify the type of material, are called: a. exterior b. interior c. profile d. foreshortened 6. A(n) is a section view drawing in which the cutting plane is perpendicularly bent to pass through all important interior details. a. full section b. revolved section c. offset section d. broken section 7. The "general" symbol used for sectioning is actually the symbol. a. iron b. steel c. wood d. concrete

cast

8. A(n) lines are used to show where a portion of an object has been torn away or removed from an object. a. object b. hidden c. cutting plane d. conventional break

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9. A is the practice of rotating a rib, web, or hole on a cylindrical object so that the rib, web, or hoIe will not be foreshortened or appear misplaced. a. conventional revolution b. conventional break c. conventional rotation d. conventional placement 10. Cutting plane lines compared to object lines are? a. lighter & thinner b. darker & thinner c. darker & thicker d. lighter & darker

Assignment 10.1 Directions: Sketch a full section of the following part. The grade will be based upon proper half section drawing techniques, line quality, and overall neatness

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Assignment 10.1 Sketch a Full Section Assignment 10.2 Directions: Sketch a half section of the following part. The grade will be based upon proper half section drawing techniques, line quality, and overall neatness

Assignment 10.2 Sketch a Half Section

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Assignment 10.3 Directions: Sketch an offset section of the following part. The grade will be based upon proper half section drawing techniques, line quality, and overall neatness

Assignment 10.3 Sketch an Offset Section

11 DIMENSIONING

OBJECTIVES At the conclusion of this unit you should be able to accomplish the following with 70% accuracy: 1. explain the importance of dimensioned multi view drawings as communication tools for designers 2. use the two systems of measurement to dimension multiview drawings: 2.1 English system 2.2 metric system 2.3 dual dimensioning 3. use the basic lines and terms to dimension a mechanical drawing by drawing the following: 3.1 dimension lines 3.2 extension lines 3.3 center lines 3.4 leaders 3.5 arrowheads 3.6 dimension numbers 3.7 notes 4. use the two different dimension placement systems 4.1 unidirectional 4.2 aligned

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5. use the two different types of dimensions to dimension a mechanical drawing: 5.1 size dimensions 5.2 location dimensions 6. use location and size dimensions to dimension a mechanical drawing: 6.1 calculation rules 6.2 placement on the most descriptive view 6.3 overall dimensions 6.4 reference dimensions 6.5 placement of small and large dimensions 6.6 placement outside of the object 6.7 placement between the views 6.8 placement to object lines 6.9 placement in small areas 7. use location and size dimensions to dimension the following: 7.1 holes 7.2 arcs 7.3 cylinders 7.4 angles 8. dimension a mechanical drawing, using CAD or freehand sketches by applying correct dimensioning techniques, so the dimensions are clear and the object can be manufactured GENERAL INFORMATION Multiview drawing is a means by which you can express an innovative design to others. Through the use of multi view drawing complicated ideas can be detailed and reviewed for changes and corrections. But before the design can be produced the size of each component of the design must be known. When dimensions and specification notes are added to multiview drawings they are referred to as working or detail drawings. A working drawing allows the design to be manufactured, provided that the dimensions are applied to it correctly. This unit gives a brief overview of the dimensioning techniques which are currently accepted and used throughout industry. The dimensioning rules and techniques presented in this unit are based upon the standards of the American National Standards Institute (ANSI). This governing body sets the dimensioning standards which industry follows.

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MEASUREMENT UNITS There are two systems of measurement used throughout most of the world -the English system and the metric system (51). The decimal inch is the unit of measurement used in the English system and the millimeter is the unit of measurement used in the metric system. Although the English system is the most familiar system for probably y most American's many major industries in the United States are using the metric system exclusively. Because of this you should understand how to dimension an object using both the English and the metric systems.

METRIC SYSTEM DIMENSIONING The metric system of measurement was adopted in France in 1791. It has become almost universally adopted throughout the world because all units o~ measurement are broken down into units of ten, thus eliminating all fractions. The millimeter is the basic unit of linear measurement and 25.4 millimeters is equal to one inch. When you are dimensioning in metric units you will round off all dimensions to the nearest whole millimeter. If the dimension is less than one millimeter, you should use a zero before the decimal point (see Figure 11.1).

ENGLISH SYSTEM DIMENSIONING In the English system dimensions can be given in fraction or decimal form. Although common fractions can be used, most dimensioned drawings are dimensioned in decimal inches, because arithmetic is more difficult in fraction than it is in decimal form.

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Figure 11.1 Metric and English dimension numbering standards If you are dimensioning in English units you should carry out all dimensions to two decimal places. If the number is less than one, no zero is given before the decimal point. DUAL DIMENSIONING Many times the mechanical drawing will have to be dimensioned in both the metric and the English system. This dimensioning technique is referred to as dual dimensioning. There are several ways in which a mechanical drawing can be dual dimensioned, but whichever method you choose should be used consistently throughout the drawing.

METHOD 1: PLACING THE DIMENSIONS ONE OVER THE OTHER Using this method one dimension is placed over the top of the second dimension. The dimension which was originally used on the drawing (either inches or millimeters) will be placed over top of the converted dimension (see Figure 11.2).

METHOD 2: USE OF BRACKETS Using this method one dimension is placed inside of a set of brackets. The dimension which was originally used on the drawing (either inches or millimeters) will be located to the left hand side of the converted dimension which is placed within the brackets (see Figure 11.2).

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Figure 11.2 Dual dimensioning techniques

DIMENSIONING LINES & TERMS There are several different types of lines and terms which are used to dimension mechanical drawings. These are given in the following paragraphs.

DIMENSION LINES Dimension lines are dark, solid, thin lines which have arrowheads on each end of them. In mechanical drawing they are broken near the middle and the size of the part is specified in this broken area (see Figure 11.3).

EXTENSION LINES Extension lines are dark, solid, thin lines which extend from a point on a view of an object and are the termination points for dimension lines. Extension lines do not touch the object. A / mm inch space is left between the object and extension lines. Extension lines and dimension lines are perpendicular to each other, and the arrowheads on the dimension lines touch the extension lines. Extension lines should be drawn past the arrowheads of the dimension lines by about / mm see Figure . .

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Figure 11.3 Dimensioning lines & leaders

CENTER LINES Center lines are dark, thin lines which are drawn by alternating long and short dashes. They are used to locate centers of cylindrical objects and axes of symmetry. Center lines can be used as extension lines when a part is being dimensioned. Center lines should always end with a long dash and when they are used as extension lines they should cross all other lines without breaking the center line with gaps (see Figure 11.3).

LEADERS Leaders are dark, thin solid lines which are drawn from a specification note or dimension to a part of an object and are completed by an arrowhead. The arrowhead should always end on a line of the object being dimensioned. Leader lines should be drawn as solid inclined lines if possible, except for a short horizontal line ¼ or mm that extends from the midpoint of the specification note or dimension and is located at the end or beginning of the specification note or given dimension (see Figure 11.3). Leaders which are drawn to circles should always be drawn so that if they were drawn through the circle they would cross through its center point. Leader lines should never cross other leader lines or dimension lines, and should cross as few other lines as possible. Use standard angles (30, 45, or 60) to draw the leader lines. Leader lines should never be drawn horizontal or vertical, cross corners of an object, or be drawn unproportionally long or short compared to the length of dimension lines on a drawing (see Figure 11.3).

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ARROWHEADS Arrowheads are used to indicate the endpoints of dimension lines and leaders. They are usually drawn 1/8"(3mm) long and their length are three times longer than their height (see Figure 11.4).

Figure 11.4 Arrowheads used in dimensioning.

DIMENSION NUMBERS Dimension numbers give the dimensions of parts; they are usually placed in the middle of the dimension line or at the end or beginning of leaders. The dimension numbers are usually 1/8"(3mm) tall and measurement units , )N, or mm) are not included. The scale of the drawing and the measurement units are specified in the title box unless they are otherwise noted on the drawing by underlining the dimension which is not to scale or using the abbreviation NTS (not to scale) next to the dimension (see Figure 11.5).

Figure 11.5 Dimensioning Numbers

DIMENSION NOTES Dimension notes are used to help clarify dimensioned mechanical drawings by providing dimension and specification information which would be hard to represent with standard dimensions. The notes are always placed on the drawing in a horizontal fashion. They should be lettered neatly / mm letters) and not crowded onto the drawing. Leaders which extend from notes

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should be placed at the beginning or ending word of the note.

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ALIGNED &

UNIDIRECTIONAL DIMENSIONING There are two different systems which can be used to place dimensions on mechanical drawings aligned and unidirectional. In the aligned system the dimension numbers are placed in the same direction as the dimension lines. The numbers are either read from the right side or the bottom of the drawing.

Figure 11.6 Aligned & Unidirectional Dimensioning In the unidirectional system the dimension numbers are placed so that they are read from the bottom of the page. The unidirectional system of locating dimensions is used more often because it is easier to place the numbers on the drawing, and the numbers are more easily read (see Figure 11.6).

SIZE AND LOCATION DIMENSIONS If an object or part is going to be correctly manufactured the manufacture must know the exact size of each part and know where each of these parts is going to be located. The dimensions which give the size of a part or object are called size dimensions. The dimensions which tell the placement or location of the sized parts are called location dimensions. Thus if a hole is going to be drilled into an object the size of the hole must be given and the center point of the hole must located with the use of dimensions (see Figure 11.7).

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Figure 11.7 Size and Location Dimensions

LOCATION OF DIMENSIONS The proper location of all dimensions is vital to the clarity of mechanical drawings. The easier the drawing is to read the less likely the chances for misinterpretation. The following dimension placement techniques are recommended by the American National· Standards Institute (ANSI). All dimensions should be given so that the manufacturer will not have to make any calculations or assume any dimensions. Only enough dimensions should be given so that the product can be manufactured. Never repeat any dimensions unless it is necessary for clarity. It is preferred practice to place the dimensions on the view of the object which is the most descriptive. The dimensions should be placed on the drawing in a clear and concise manner. They should be placed between the views of the object and not on the object. The dimensions should not describe hidden features if at all possible. The smaller dimensions are placed closest to the object with the larger dimensions being located outside, but parallel to the small dimensions. This eliminates the problem of crossing dimension lines with extension lines (see Figure 11.8).

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Figure 11.8 Placement of Dimensions Many times several dimensions will be located next to the object lines, or will be located the same distance from the object lines. When this occurs the dimensions are placed in a row the same distance from the object line. The largest dimension which is located the farthest distance away from the object is called an "overall dimension". This dimension, as the name implies, gives the overall size of the object. If there is a row of dimensions, one dimension is usually omitted, because the overall dimension gives the distance of the omitted dimension. If you feel that none of the dimensions should be omitted, because the clarity of the drawing will be decreased, then one of the middle dimensions should be labeled as a reference dimension (REF) (see Figure 11.9).

Figure 11.9 Overall and Reference Dimensions.

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Although you should never cross dimension lines with object lines, other dimension lines 'or extension lines, it is permissible to cross extension lines with object lines or other extension lines. If two extension lines cross each other or the extension line is crossed by an object line, the extension line is drawn solid, and no gaps are left where these lines intersect (see Figure 11.10).

Figure 11.10 Use of Extension Lines. Place the dimensions near enough to the part being dimensioned so that they can be read clearly. The first set of dimension lines is located ¼ mm from the object lines on the drawing. Each successive set of dimension lines are located ¼ mm away from the preceding set of dimension lines. This is the standard placement procedures for smaller mechanical drawings. If the mechanical drawing is larger than these distances may be increased, but the spacing must remain consistent throughout the drawing (see Figure 11.11).

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Figure 11.11 Spacing between dimension lines. Whenever possible the dimensions should be placed outside of an object. If the dimensions are placed on the object it will appear cluttered and the dimension or extension lines could become confused with visible lines. The exception to this rule is the dimensioning of deep notches. Because dimensions should be located next to the part being dimensioned it is easier to dimension deep notches inside the notch where extension lines will not be crossing over a large portion of the drawing (see Figure 11.12).

Figure 11.12 Placement of Figure 11.13 Placement of dimensions in deep notches dimensions between the views. If possible avoid dimensioning to hidden lines. In most cases the dimension can be given from an object line in a different view. If a dimension is common to two views it should be placed between the views. For clarity it is helpful in many instances to place the dimension in more than one view, but do not repeat any dimension unless it is necessary to make the drawing more clear (see Figure 11.13). When the area around an object is small, common dimensioning techniques should not be used, because the dimensions will appear cluttered and they will be hard to read (see Figure 11.14). If there are several rows of dimensioning which lay on top of each other the dimension numbers should be staggered, not drawn one above the other. This makes the dimensions easier to read (see Figure 11.15).

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Figure 11.14 Dimensioning in small areas dimension numbers

Figure 11.15 Staggering the

DIMENSIONING HOLES Location dimensions must be used to accurately locate the center point of holes. Once the location of the center point has been dimensioned, the diameter abbreviated or Ø in older drawings "DIA "of the hole must be given. This is done through the use of a leader. The leader is drawn only to the outside edge of the circle and not to its center point. The arrowhead will be pointing toward the center point (see Figure 11.16). Place dimensions in holes if the holes are large enough to hold the dimension numbers and leaders and still be legible. If this type of dimension is used omit the abbreviation Ø. If there are several holes located on an object and their diameter is the same, all of the hole diameters do not have to be given, but size dimension one hole and use a note to specify that it has the same diameter as the other holes (see Figure 11.16). If the metric system is being used then the diameter dimensions must be preceded by the symbol Ø.

Figure 11.16 Dimensioning Holes Figure 11.17 Dimensioning Arcs Like holes the center point of the arc must be given by location dimensions. A leader is used to give the size dimension of the arc. The leader is drawn from the center point of the circle and the arrowhead points toward the outside of the circle. The term used to give the size dimension for arcs is the radius (R) see Figure . . The R follows the dimension in the English system; however, in the metric system, the convention is to precede the dimension with the symbol R.

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DIMENSIONING CYLINDERS Cylinders may be either solid or have holes drilled through them. Cylinders should be dimensioned in the rectangular view with the use of dimension lines. The cylinder may be dimensioned through the use of one or two views. If one view is used the dimensions must be labeled Ø (see Figure 11.18).

Figure 11.18 Dimensioning Cylinder

DIMENSIONING ANGLES There are two methods which can be used to dimension angles. You can locate the ends of the angle lines or give the angular measurements in degrees. When you dimension an angle it is customary to use only one or the other method (see Figure 11.19). Avoid placing the dimensions in the area indicated in Figure 11.20; because the dimensions will be read from the bottom of the page (see Figure 11.20).

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Figure 11.19 Dimensioning Angles

Figure 11.20 Locating Angular Degree Dimensions

SUMMARY Without the knowledge of how to correctly apply dimensions to multiview drawings you as the designer or engineer cannot validly communicate your design to others. Dimensions and annotations are needed by manufactures to produce designed products. The lines, arcs, circles, and other 2D geometry describe the features of an object. The dimensions give the size and location of the features that comprise the product. Figure 11.21 shows a complete and accurate dimensioned multiview drawing, following ANSI standards and conventions.

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Figure 11.21 ANSI Standard Dimensioned Drawing

TECHNICAL TERMS 1. Aligned Dimensions – dimensions which are placed parallel to an object and are read from the bottom and right side of the object. 2. American National Standards Institute (ANSI) – governing body which sets manufacturing standards for American industries.

3. Center lines – are dark, thin lines which are drawn by alternating long and short dashes. They are used to locate the centers of cylindrical objects and axes of symmetry.

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4. Decimal dimensions – dimensions which are written in decimal form and are the basic or theoretical perfect size of a feature. 5. Decimal inch – the basic linear measurement unit used in the English system of measurement. One inch equals 25.4 millimeters.

6. Dimension – a linear distance, angular measurement, or a note which describes the size of an object and gives the exact location of component parts of the object. 7. Dimension lines – are dark, solid, thin lines which have arrowheads on each end and specify the size of an object. 8. Dual dimensioning – dimensioning an object with the use of both the English and metric systems.

9. English system – the measurement system which is commonly used in the United States and uses the inch as its basic unit in linear measurement. 10. Extension lines – are dark, solid, thin lines which extend from a point on a view of an object and are the termination points for dimension lines.

11. Leaders – are dark, thin, solid lines which are drawn from a specification note or dimension to a part of an object and are completed by an arrowhead. 12. Location dimensions – locate the component parts of an object.

13. Metric system – the measurement system used throughout most of the world and uses the millimeter as its basic unit of linear measurement.

14. Millimeter – the basic linear measurement unit used in the metric system. There are 25.4 millimeters in an inch.

15. Overall dimensions – give the overall or largest dimension of an object. 16. Reference dimensions – dimensions which are not necessary to produce a part or product, but are used to provide additional information for it manufacture or assembly.

17. Size dimensions – describe the overall size of a part.

18. Specification notes – many times referred to as annotations are notes which explain or give special instructions about how a part or product is to be manufactured.

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19. Unidirectional dimensions – dimensions which are placed on the drawing so that they are all read from the bottom of the drawing.

UNIT QUIZ Directions: Answer the following questions by selecting the best response. 1. If a multiview drawing contains specification notes and dimensions it is referred to as a(n) drawing. a. Working b. Mechanical c. Production d. final 2. What is the approximate distance between dimension lines? (objective 6) a. 3/16" b. 1/8" c. 1/4" d. 3/8" 3. What is the approximate distance between the object and the first dimension line? (objective 6) a. 3/16" b. 1/8" c. 1/4" d. 3/8" 4. If possible, where in relation to the given views of an object should the dimensions be located? (objective 6) a. outside of the views b. between the views c. on the views d. on the right side of the views 5. If dimensions are stacked (one dimension above another) the dimension numbers should be: (objective 6) a. placed below each other b. drawn or sketched 1/2 size c. staggered from the line above d. placed outside of the dimension line 6. The dimensioning system which allows you to read the dimensions from the bottom of the page is called? (objective 2) a. British b. American

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7. The basic unit of linear measurement in the metric system is? (objective 2) a. decimal inch b. millimeter c. meter d. inch 8. What is the symbol used to represent a diameter with current ANSI and ISO standards? a. IDA b. DIA c. R d. Ø 9. What dimension gives the total or largest size of an object? (objective 6) a. location dimension b. detail dimension c. size location d. overall dimension 10. _________lines point to the arc or circle being dimensioned. (objective 3) a. Dimension b. Leader c. Extension d. Location

ASSIGNMENTS 11.1 – 11.2

Directions: Given the dimensioned isometric drawing of the object construct a two-view sketch and dimension it using unidirectional English system decimal dimensions. The assignment grade will be based upon proper use of dimension lines and terms, unidirectional dimensioning techniques, size and location dimensions, and overall neatness. SCALE: 1:1

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Assignment 11.1 Two View Dimensioned Sketch/Drawing

ASSIGNMENTS 11.3 – 11.4

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Assignment 11.2 Two View Dimensioned Sketch/Drawing

Directions: Given the multiview drawing of the object construct a multiview sketch and dimension it using unidirectional English system decimal dimensions. The assignment grade will be based upon proper use of dimension lines and terms, unidirectional dimensioning techniques, size and location dimensions, and overall neatness. SCALE: proportional

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Applied Geometry for Engineering Design Assignment 11.3 Two View Dimensioned Sketch/Drawing

Assignment 11.4 Two View Dimensioned Sketch/Drawing

ASSIGNMENT 11.5 Directions: Given the dimensioned isometric drawing of the object construct a three-view sketch and dimension it using unidirectional English system decimal dimensions. The assignment grade will be based upon proper use of dimension lines and terms, unidirectional dimensioning techniques, size and location dimensions, and overall neatness. SCALE: 1:1

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12 INTRODUCTION TO CATIA V5 INTRODUCTION CATIA V5 is high-end 3D CAD (computer-aided design) solid modeling software that allows you to select a wide range of design options for mechanical design in a product lifecycle management environment. Unlike other CAD packages, CATIA V5 is a process modeler, which means it is designed to have all the digital tools necessary to not only design a part but to do digital operations to a product and allow it to be produced and revised throughout its lifecycle. Each different tool has it own set of standard toolbars and icons associated with it, and the different types of tools that are available in CATIA V5 are called "workbenches." There are several different types of workbenches available in CATIA V5. The focus of this book will be on Part Design, Assembly Design, Drafting, and Digital Mock-Up (DMU). OBJECTIVES After completing this chapter you will be able to: 1. Start CATIA V5. 2. Identify and utilize the CA11A V5 interface. 3. Identify and use CATIA V5 Pull-clown menus to create and manipulate geometry. 4. Identify and use CATIA V5 toolbars and icons menus to create and manipulate geometry. 5. Describe the basic functionality of the specification tree. 6. Describe the basic functionality of the compass tool. 7. Describe CAD environmental settings and their importance.

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8. Describe a start part and its importance. 9. Describe the importance of naming features in the specification tree.

STARTING CATIA V5 Locate the CATIA V5 icon and double click on it to start CATIA V5. When CATIA V5 is loaded from the standard configuration it will automatically default to the Product (assembly) Workbench. Parts must first be developed before they can be combined into assemblies thus the Product Workbench needs to be closed. Close the Product Workbench by clicking on the "X" in the upper right hand corner. Locate the Start pull-clown menu and under the Mechanical Design option select the Part Design option. The Part Design Workbench will now appear as the CATIA V5 interface. Maximize the Part Design Workbench and the CATIA V5 interface should appear similar to Figure 12 .01.

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Figure 12.01 The CATIA V5 User Interface

CATIA V5 INTERFACE CATIA V5 is a true Windows interface. Thus, if you have previously used any Windows package you will be very comfortable using CATIA V5. It has several different methods in which you can interact with it. Pull-down menus, toolbars, icons, and key commands can all be used to invoke commands in CATIAV5. Notice in Figure 12.01 that there are pull-down menus across the top of the CATIA V5 interface and toolbars and icons located at the bottom and right hand side of it. There are also three perpendicular sketch planes in the middle of the screen that define the world coordinate position of 0,0,0. In the upper left hand corner is the "Specification Tree." In the upper right hand side of the screen is the "compass" tool. The area surrounding the three sketch planes is the three dimensional workspace. This is the geometry area where all models and parts are constructed and located. All of these various parts of the CATIA V5 interface allow you to construct or view models or assemblies in CATIA V5 and they will be covered in greater detail later.

CATIA V5 PULL-DOWN MENUS The different pull-down menus found at the top of the CATIA V5 interface allow different commands to be used. The Start Menu (see Figure 12.02) allows access to different workbenches in CATIA V5. Multiple workbenches can be open at once in CATIA V5 but performance may be diminished. Likewise, having multiple part or assembly files opened at once can reduce the performance of CATIA V5 depending on the performance of the workstation. The Start Menu also allows the most recently used CATIA V5 files to be displayed for easy access. The file that is currently being used is displayed in the Start Menu with a check mark beside it. Finally, you can exit CATIA V5 from the Start Menu. The TeamPDM pull-down menu allows this built-in PDM (Product Data Management) tool to be used to archive parts, assemblies, and other Meta data associated with CATIA V5. PDM is a very broad and complicated topic and it will not be covered in this book. The File pull down menu (see Figure 12.03) allows you to access all typical Windows file operations such as opening and saving files. New and existing files

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can be loaded through the use of the New and Open commands. Files can also be Saved as the same name or saved as a different name using the SaveAs command. Prints can be made by the using the Print command and printer settings can be modified by the Printer Setup command. Like in the Start menu a list of the most recent files you have used is displayed at the bottom of the File pull down menu. Also, CATIA V5 can be exited from the File pull down menu. The Standard toolbar (see Figure 12.04) allows you to do many of the same commands as the File Pull down menu such as opening new and existing files, save files, and print files along with other commands.

Figure 12.02 The Start Menu

Figure 12.03 The File Pull Down Menu

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Figure 12.04 The Standard Toolbar The View and Window pull down menus allows you to use different options to view parts and they also allow different parts of the CATIA V5 interface to be displayed or not be displayed, such as the specification tree. The View and Window commands will be covered in greater detail in Chapter 2. The remaining pull-down menus (Edit, Insert, Tools, and Help) contain specific CATIA V5 commands and these will be discussed in greater detail where they apply in later chapters.

TOOLBARS AND ICONS CATIA V5 extensively uses icons and toolbars and at times their placement can become confusing because they can be moved to new locations or turned off. Figure 12.05 shows the default toolbars in their default placement. Notice that in their default positions the toolbars will either be placed on the right hand side of the interface or at the bottom of it. Many times it is easier to work with some of the toolbars turned off or moved to another location on the interface.

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Figure 12.05 The Default Toolbars and Default Placement Figure 12.06 shows a toolbar that was moved from the right-hand toolbar anchor into the geometry area of CATIA V5. Notice that it maintains its vertical orientation because this was the orientation of it when it was anchored. Also notice that you cannot read the name of the toolbar.

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Figure 12.06 A Toolbar Moved Into the Geometry Area of CATIA V5 In Figure 12.07, the toolbar was moved to the top of the CATIA V5 interface and anchored. This changes the orientation of the toolbar from a vertical to a horizontal orientation.

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Figure 12.07 The Toolbar Horizontally Anchored at the Top of the CATIA V5 Interface

In Figure 12.08, the toolbar was again moved into the geometry area and it retains its horizontal orientation. The horizontal orientation allows this toolbar to be identified as the "Sketch-Based Features" toolbar. This technique is used to help you identify the names of toolbars when they cannot be identified because they are orientated vertically.

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Figure 12.08 The Toolbar Orientation After It Was Moved Back Into the Geometry Area of CATIA V5 A second important point about toolbars in CATIA V5 is that not all the toolbars are displayed at once. This can become confusing because you may not be able to locate a required toolbar. Figure 1.09 shows the right side of the bottom toolbar. Notice that there is a">>" present. The">>" means that there are more toolbars anchored at this location than can be displayed. In figure 1.10 the View Tool bar was placed into the 3D drawing area which caused the Analysis Toolbar to appear and the ">>"to disappear. When the ">>" disappears this indicates that there are not any more hidden toolbars. The ">>" can also appear at the bottom of the right hand toolbar anchor or at the right end of the top toolbar anchor.

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Figure 12.09 The ">>"Displays and Indicates that There are Hidden Toolbars

Figure 12.10 Un-anchoring a Toolbar Removes the ">>" Thus All the Toolbars Are Displayed Some toolbars contain other toolbars within them that can be expanded to display additional icons. In Figure 12.11 the Isometric View icon, the caret was picked and the Quick view toolbar was displayed. Once the toolbar has been

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expanded, it can be moved independently from the toolbar from which it was expanded (see Figure 12.12).

Figure 12.11 Display of Quick View Toolbar Under the Isometric View Icon

Figure 12.12 The Quick View Toolbar Moved to Another Location Toolbars can also be turned off if they are not needed. Simply move the unneeded toolbar into the geometry space and pick on the "X" and this will turn off the toolbar.

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In Figure 12.13, all of the default toolbars have been moved into the geometry area of CATIA. Notice that the right anchor bar disappeared and also notice how much clutter that these toolbars present in the geometry area.

Figure 12.13 All the Toolbars Have Been Moved into the Geometry Area Many times you will want to move several toolbars into the geometry space and then later anchor or turn them off. After changing the positions of the toolbars or turning them off, you may discover that you cannot find a desired toolbar. By placing your cursor over one of the anchor bars and clicking the right mouse button, the toolbar pop-up window appears (see Figure 12.14). The toolbar popup window allows you to turn on and turn off individual toolbars by checking or un-checking the box next to the desired toolbar. If you turned off a toolbar and you need to use it again, just select it from the toolbar pop-up

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window, and it will be displayed. In Figure 12.15, all of the toolbars have been turned off.

Figure 12.14 Toolbar Pop-up Window

Toolbars can be restored individually or all of the toolbars can be restored all at once. Notice at the bottom of the toolbar pop-up window there is the Customize… option. Selecting the customize option causes the Customize dialog box to be displayed (see Figure 12.16). The customize dialog box allows you to customize menus, toolbars, and other parts of the CATIA V5 interface. Notice that there are five tabs available in the Customize dialog box. Only the Toolbars tab will be discussed in this chapter (see Figure 12.17). This tab has

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several options, but, because many times toolbars may become hard to locate, only the Restore all contents and Restore position options will be discussed. The Restore all contents option does what the name implies in that it turns on or restores all of the default toolbars. The problem with this option is that all of the toolbars may be turned on but you may not be able to immediately locate them. The Restore position option will restore all toolbars and places them in their default position in the CATIA V5 interface. Remember this command because many times you will not be able to find a toolbar even if it appears to be on and no ">>" appear.

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Figure 12.15 CATlA V5 Interface With All the Toolbars Turned Off

Figure 12.16 Customize Dialog Box

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Figure 12.17 Customize Dialog Box Toolbars Tab

THE SPECIFICATION TREE The Specification Tree is one of the most powerful tools of CATIA V5 (see Figure 12.18). It can be used to select, modify, hide, and perform other functions to a CATIA V5 feature, part, or product. Notice that the specification tree can be expanded or reduced by clicking on the + and - icons. Also note as the cursor is moved over different areas of the specification tree, different pieces of geometry will highlight. This allows you to do specific operations to the selected features, parts, products, parameters, or relations.

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Figure 12.18 Specification Tree

THE COMPASS TOOL The Compass Tool (see Figure 12.19) allows features, parts, or assemblies to be repositioned in the 3D geometry area. Through the use of the compass, linear translations along the x, y, or z axes can be performed. Likewise revolutions around the x, y, or z axes can also be performed with the compass tool. Advanced translations, revolutions and other operations can also be done with the compass tool, and these will be covered in more detail in later chapters.

Figure 12.19 Compass Tool

ENVIRONMENT SETTINGS Every company uses different standards so that all CAD files and their environments are identical no matter who the designer is, what workstation is being used, or which part is being developed. Many of these standards are controlled by environmental settings within the CAD package. In CATIA V5, the environmental settings are found under the Tools pull- down menu by using the

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Options command. Different options can be changed to have CATIA V5 perform or appear in different ways. Figure 12.20 shows the options dialog box. There is an option tree on the left side of the Options dialog box with corresponding tabs related to the selected option in the specification tree. If a different option is selected the corresponding tabs will likewise change to reflect the option selected. For example, if the Parameters and Measures option is selected from the option tree the Knowledge, Measure Tools, Parameters Tolerance, Report Generation, Symbols, and Units tabs will appear. In Exercise 1.1 that follows, the environment will be changed to reflect the standard settings that will be used to develop parts, assemblies, and drawings that will be constructed later.

Figure 12.20 The Options Dialog Box

EXERCISE 1.1 - ENVIRONMENTAL SETTINGS In this exercise, different environment settings will be changed within CATIA V5. These settings will be used throughout the book as the default standard. The relevance of these environmental changes will be discussed. A new part file will

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be loaded and saved as "startpart" . This file will be used as the default or start file for every part that will be constructed. 1. LoadCATIAV5 2. Close the default product session. 3. Under the Start Menu select Mechanical Design/Part Design option to start a new part design session. 4. Maximize the part design window.

CHANGING THE ENVIRONMENTAL SETTINGS 1. Select the Tools pull-down menu and select Options. 2. Select the General option from the options specification tree and the General tab. 3. The User Interface Style should be set to P2. CATIA V5 has three different types of interfaces and each have different capabilities. Pl is the basic interface that is cheaper but does not have many of the tools available in it. The P3 interface is the most cost expensive interface has the most options available in it. The selected P2 interface is a very powerful interface and is also very easy to use, thus it will be the default interface. 4. Under the General tab, set the Automatic Save to off by making sure that the Automatic save every button is not set to on. See Figure 12.21. 5. In the specification tree, select the General/Display option and the Visualization Tab. Notice that the colors of different elements in CATIA V5 can be changed. The default background color is a graduated blue color. If this color is not acceptable, then a different background color can be selected, and the graduation can be turned off. DO NOT change any of the other default element colors or highlight items may not appear correctly on the screen.

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Figure 12.21 General Options General Tab Dialog Box Settings 6. In the specification tree, select the General/Parameters and Measurement option and the Knowledge tab. 7. In the Parameter Tree View, make sure that both the With Value and With Formula boxes are selected. This will allow all values and formulas to be displayed in the specification tree. This is important when formulas are used to create relations between geometric elements. See Figure 12.22. 8. While still in the Parameters and Measurement options, use the right arrow to locate and select the Units tab. 9. Under the Units field, select the Inch (in) option unit in the pull down menu in the lower right hand corner of the Units box. This is where the units can be changed from imperial to metric units or metric to imperial units.

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Figure 12.22 General/Parameters and Measure Option Knowledge Tab Settings 10. Under the Dimensions display the number of decimal units that are read/write can be changed. Accept the default of three. See Figure 12.23. 11. In the Specification tree, select the Infrastructure option and expand the tree by clicking on the+ icon and select the Product Structure Tab. 12. Under Part Number, make sure the Manual input checkbox is checked. When a new part or product is started CATIA V5 will automatically ask for a part number before starting a new part or product. See Figure 12.24. 13. In the Specification tree, select the Infrastructure option to expand the tree and select the Product Structure option and the Tree Customization tab. All of the check boxes under Specification Tree Order should be "yes". This

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will allow all of these elements to be displayed in the specification tree. Do not worry about ones without words. See Figure 12.25.

Figure 12.23 General/Parameters and Measure Option Units Tab Settings 14. In the specification tree select the Mechanical Design option and select the Sketcher option and the Sketcher tab. 15. Under the Grid option, the Display box should be the only box turned on. This allows the grid to be displayed when the sketcher is being used. By not checking the Snap to point checkbox the cursor is not forced to grid locations in sketch mode. This allows for more freedom in sketch mode by not forcing the cursor to be restricted to grid points. See Figure 12.26. 16. Under the Constraint option, all checkboxes should be unchecked. By default CATIA V5 automatically will create geometric and dimensional constraints as geometry is being created. For a beg inning user this typically will cause confusion when unwanted constraints are automatically created.

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By not having automatic constraints, a new user will only place the needed constraints and will better understand how they are used and why they are important. Once constraints are understood then automatic constraints can be used. See Figure 12.26.

Figure 12.24 Infrastructure/Product Structure Option Product Structure Tab Settings 17. Likewise, all SmartPick options under Constraints should be unchecked and then select Close and OK. See Figure 12.26. 18. Save the file using the SaveAs command under the File menu, so it can be used as the seed or start part for all future models. This startpart file will now be used to start every other part file. The settings will be already set with one exception. The default units system is now set to inches. If a metric

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part needs to be constructed the units option will have to be changed to metric.

Figure 12.25 Mechanical Design/Part Design Option Display Tab Settings

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Figure 12.26 Mechanical Design/Sketcher Option Settings

LABELING THE DEFAULT PLANES 1. Place your mouse over the xy plane in the Specification Tree. 2. Click the right mouse button. A pop-up menu will appear. 3. Select the Properties option. The Properties dialog box will appear. 4. Select the Feature Properties tab. 5. Change the feature name from xy plane to xy plane (horizontal). See Figure 12.27

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Figure 12.27 Renaming the xy plane. 6. Click on the OK button or hit enter. 7. Use the same procedure to rename the yz plane to yz plane (frontal) and the zx plane to zx plane (profile). 8. When you are completed the Specification Tree should appear identical to Figure 12.28.

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Figure 12.28 Renamed CATIA V5 Sketch Planes. 9. Use File Save as command to save this file as "startpart" in the correct file vault location. 10. Locate the startpart file in Windows Explorer and right click on it. In the pop up menu, select the Properties option. In the Properties dialog box, check the Read Only attribute. This will keep the startpart file from being accidentally over written by a model file.

EXERCISE 1.2- NAMING FEATURES IN THE SPECIFICATION TREE In this exercise you will be shown how to rename geometric features, relations, and parameters in the specification tree. Using logical naming conventions to rename specification tree entities, such as geometric entities, allows for their quick and logical identification in the future. Many times, long periods of time will occur between when a model is constructed and when it is used again for making an engineering change order by the designer or by another engineer. If the CATIA V5 default specification tree names are used, it makes it hard to identify specific features. Load the CATIA V5 part file named Piston. CATPart and notice the specification tree that is located on the left side of the screen (see Figure 12.29).

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1. Move the cursor over the PartBody branch of the specification tree and expand it by placing the cursor over PartBody and double clicking with the left mouse key. Your expanded tree specification tree should appear similar to Figure 12.30. The PartBody branch of the specification tree is where the geometry that comprises the model is located. Notice that there are several sketches, pockets, and fillets that determine the makeup of the model. If there are several different types of a similar geometry, they will be labeled the same except for a different number attached to the end. The nearly identical names are automatically assigned, and because of this features should be relabeled. As you can tell all of these similar names could quickly lead to confusion.

Figure 12.29 The Default Figure 12.30 The Expanded Specification Tree Specification Tree 2. Place the cursor over the PartBody branch of the tree and click with your right mouse button. Notice a pop-up box appears. It has several options

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including Hide/Show, which would either hide or display the selected entity. Select the Properties option and the Properties dialog box appears (see Figure 12.31)

Figure 12.31 The Specification Tree Properties Dialog Box.

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3. Select the Feature Properties tab. Notice the feature name input field. This is where you can type in a new name for the feature. The default name should be the same name that appeared in the model tree. 4. Close this window. 5. Highlight the Shaft.1 and rename it to Piston Body and then click on the OK button or press Enter. 6. Notice that Shaft.1 has been renamed to Piston Body in the specification tree. 7. Use the same procedures to rename the following features in the specification tree: Pocket.1 Pocket.2 Pocket.3 Pad.1 Hole.1

= = = = =

RING CUT OUT LUBE GROOVES MAIN INTERNAL CUTOUT BOSS CONNECTING ROD HOLE

8. Save y our file.

SUMMARY There are several workbenches available in CATIA V5, such as the Mechanical Design and Shape workbenches, and each of these have their own unique set of toolbars and commands. In this chapter, you learned how to load CATIA V5 and learned about its interface. You were exposed to pull-down menus, toolbars, and icons. The basic functionality of both the specification tree and compass tool were explained. You created a startpart by changing the environmental settings of CATIA V5 and learned how to name features through the use of the specification tree. Viewing options will be discussed later.

13 BASIC WORKBENCHES AND VISUALIZATION

INTRODUCTION To successfully utilize any 3D modeling program you must understand and be able to visualize the geometry that you are viewing. CATIA V5 has several commands that allow you to visualize parts, assemblies, drawings, and many other types of geometry. This chapter will give you a basic overview of these commands and how to use them to help you visualize simple to complicated mechanical components. We first will take a look at some background information of CATIA V5 and its various workbenches. OBJECTIVES After completing this chapter you will be able to: 1. Understand the file extension usage of CATIA V5 documents. 2. Identify the common workbenches and their uses in CATIA V5. 3. Understand the concept of visualization as a result of moving your position in relation to the fixed position of an object. 4. Identify and utilize the View toolbar. 5. Understand and apply the Fit In All command to make a product appear as large as possible in the geometry area. 6. Use the pan command to change your viewpoint of a document from left to right and/or up to down.

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7. Identify and apply the Rotate command to rotate your viewpoint around a document using a spherical viewing system. 8. Use the Zoom In command to move your viewpoint closer to a document so that small details can be displayed on the screen large enough to be easily viewed. 9. Use the Zoom Out command to move your viewpoint further away so that a larger view of a document will be displayed. 10. Use the Zoom Out Area command to zoom into a specific area as defined by the zoom boundary box. 11. Use the Normal View command to get a viewpoint that is perpendicular to a selected plane. 12. Use the Quick View Toolbar to select one of the six principle views or and isometric viewpoint of the object. 13. Use the View Mode Toolbar to change the appearance of the document.

CATIA V5 TERMINOLOGY CATIA- Computer-Aided Three Dimensional Interactive Application CATIA Version 5 is an integrated suite of Computer-Aided Design (CAD), Computer-Aided Engineering (CAE), and Computer-Aided Manufacturing (CAM) applications for digital product definition and simulation. It is a product of Dassault Systemes, France. An industry standard today, CATIA has been Dassault Systemes' flagship solution since the company's creation in 1981. In that year, Dassault Systemes entered into a strategic partnership with IBM to distribute CATIA worldwide. In 1999, CATIA became the most popular product development system in the world. Its most current release is Version 5. Dassault updates the CATIA V5 suite of tools every few months with new releases. Unfortunately, some of the models created in present releases are not backward compatible. In other words, a CATIA V5 model created in Release 10 of CATTA V5 cannot be edited or viewed in Release 9. Forward compatibility is however maintained.

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CATPART This is a proprietary file format used within CATIA V5 to save 3D geometry information. Models or 3D geometry created within CATIA V5 are always referred to as Parts and hence the file extension .CATPart.

CATPRODUCT An assembly is a collection of parts, which are constrained together to give meaningful shape or mechanism. An assembly is first created by making a number of parts and then bringing them together into a single document known as a Product document. CATIA uses the .CATProduct file extension to denote assembly files, which contain references to all the CATParts, and how they are attached or constrained together. Remember that CATProduct documents do NOT contain the CATPart files within them. They just provide a reference or a link to the location of the CATPart files used in the assembly. So for example, if you change the location of the any CATPart file used in the assembly, then the CATProduct file will fail to load properly and CATIA will return an error message.

DMU DMU is an acronym for Digital Mock-Up. It is the virtual design and simulation in 3D of a product and all of its components. Digital or virtual mock-up reduces the number of physical prototypes required during the design phase of any product. Physical prototypes are very expensive and time consuming to manufacture, so more and more companies are using accurate 3D models to simulate real world testing. An example of how DMU helps save time and money is when a designer can check for interference or clash between parts such as a turbine and its casing.

COMMON CATIA V5 WORKBENCHES The entire CATIA V5 Solutions package is divided into a number of workbenches. Each workbench deals with a different part or process of a product's lifecycle. Knowing each and every workbench is not a requirement to make successful CAD models. In fact, to create a complete 3D representation of a simple part, all you would need to know is the Part Design workbench. CATIA V5 consists of workbenches to create and assemble 3D geometry. It has drafting and sketching workbenches to create 2D sketches. Complex curved

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surfaces like a computer mouse can be created with the shape design and surface-modeling workbench. The Finite Element Analysis (FEA) workbench, lets you calculate stress and strain values. The Digital Mockup (DMU) workbench allows you to review and measure designs. With the DMU Kinematics workbench, you can add motion and animation to your models. For example, you can have a completely modeled and running internal combustion engine. Some advanced tools also deal with ergonomics and intelligent models, which can be programmed using macro languages.

CATIA SKETCHER The Sketcher is actually part of the Part Design Workbench. All 3D geometry can be created by a primitive 2D shape or profile. You can start off by creating simple lines and circles plus use complex geometry like conics and splines. The power of this tool lies in the amount of control you have in deciding the final 3D shape. The entire process of creating a sketch is enhanced with the help of geometric and dimensional constraints. You will later see these topics introduced in detail.

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Figure 13.01 A Stapler Rail Completely Modeled in Part Design Workbench as a Single Part

CATIA PART DESIGN The Part Design workbench is one with which you will be working most of the time. 3D geometry may contain simple curved surfaces that can be constructed very easily. A number of operations like extrusions and revolutions can be done on 2D shapes to convert them to 3D geometry. You will learn about most of these tools and how to use them. Remember, there is no "single" path to construct a model. It can be done in various ways. The path you decide to take is defined by your intent in creating the geometry and its use. Sometimes you might use a certain procedure, which won't allow you to go back and make changes that you want to make. This is a scenario to be avoided. The tutorials in this book may not always represent the best way to model the part. But the

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methods described will provide you with an understanding of the reasoning behind the steps followed (see Figure 13.01).

Figure 13.02 Assembly of a Stapler

CATIA ASSEMBLY DESIGN Suppose you want to model an everyday object, such as a simple ballpoint pen. Your first step would be to dismantle a suitable product, which you want to replicate and then measure all the components. You proceed to accurately model each of the components within the Part Design workbench. After you have saved all your files, you come to the Assembly Design workbench, where you can import each of your CATParts and bring all the pieces together to make a digital pen. To reduce the margin of error, it is important that the modeling of each part is done with care, otherwise interference can occur. As you will later see, proper assembly design is a stepping-stone to making a moving model. An assembly is

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not created by just moving the parts close to each other and "seeing" if they touch each other. There are certain physical constraints that can be imposed on parts so that they attach to another part in an accurate fashion. For example, you can constrain two surfaces to always remain in contact with each other. In another case, you can constrain two pipes to always remain on the same axis. With a combination of such constraints, it is possible to have completely accurate digital version of any object you wish to make (see Figure 13.02).

CATIA DRAFTING Suppose you have created a model within CATIA. And you now want to manufacture that part. But the shop that is to manufacture the product does not run CATIA nor does it have Numerically Controlled (NC) machines to do the job. You need to make drawings on paper, which the machinist will use to check dimensions etc. This is where the Drafting workbench becomes useful. After you create your model, all you need to do is choose the views of the model, which most completely describe it and then add dimensions to these views. The machinist can now look at your "model" and accurately machine it. Why would a person use CATIA or any other CAD package for that matter if the drawings could have been just done by hand using pencil and paper? Imagine if you had to make a few changes to a part. Depending on the extent of the changes, you might have to redraw the entire part by hand. Compare that to making the changes in CATIA taking just a few minutes and then taking prints for viewing. Or think about how easy it is to make prints of different views of the model. You can have detailed views, section views, broken views etc. All this can be done with just a few clicks of the button. There is no need to draw each view separately while trying to maintain the same level of accuracy. This is the main reason why almost all industries use Computer-Aided Design (CAD). Flexibility of this kind is saving companies millions of dollars every year (see Figure 13.03).

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Figure 13.03 Orthographic Views of the Stapler Rail

CATIA DMU As described earlier, the Digital Mock-Up workbench is used to review designs and make measurements. A common scenario of how it can be used is as follows. Consider a major airplane manufacturer. An average sized commercial airplane contains close to three million parts. The entire design of the aircraft is divided into different groups of the company. Each group has a group of designers under a team leader. For example, one group working on the wings, one on the tail, one on the hydraulics, another on HVAC units and so on. And all the designers within a group are working collaboratively in designing their section of the plane. Now the job of each team leader is to make sure that each member of his group is working according to schedule and that his work is accurate and does not interfere with other existing parts. So the team leader would ideally do a weekly review of the assembly as it progresses towards completion. This is where the DMU workbench comes into play. The leader can do a quick "flythrough" over the assembly to check on its progress. He can measure distances and clearances

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without having to open the files in Part Design or Assembly Design workbench. He can also do a clash analysis to look for interference between parts. The DMU workbench has dedicated tools, which makes the team leader's job easy and quick (see Figure 13.04)

Figure 13.04 DMU Workbench Being Used to Check for Interference on a Stapler

VISUALIZATION OF GEOMETRY Several tools can be used to visualize parts, assemblies, and drawings in CATIA V5. Visualization as defined in this context is the viewer's position relative to an object. No matter what tool you use to visualize the geometry, one important concept must be understood: the orientation or the location of the geometry does not change when your view of a part or feature is changed, but rather your position relative to the part or feature changes. Think about a view of the

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backside of your house. More than likely the mental image that you developed was a result of being located behind your house and looking at it from this position. This is the same concept that you must apply to viewing objects in CATIA using the various viewing commands. Using the different view commands moves your viewing position in relation to the object that you are viewing.

VIEWING TOOLS CATIA V5 has several viewing tools that allow you to change your view of the geometry or to change the display of it. In the following paragraphs most of these commands will be explained. All of the view commands can be found under the View pull down menu or through the use of icons. Unless a command does not have an icon all command references will be made to icons. Figure 13.05 shows the View toolbar. The view toolbar contains almost every view command that you will need to view geometry. Each view command will be discussed in detail below except the Fly Mode command (see Figure 13.06), which will be discussed later in the book.

Figure 13.05 View Toolbar

Figure 13.06 Figure 13.07 Fly Mode Icon Fit All In lcon

The Fit All In (see Figure 13.07) command either moves your viewpoint closer or further away from the part so that the entire part is displayed as large as possible in the geometry area. In Figure 13.08, the displayed part is very large because an area of it was zoomed in and the entire part is not completely shown within the geometry area. Figure 13.09 shows the resultant display of the same part after the Fit All In command has been invoked. Your viewpoint was moved farther away from the part thus allowing it to be displayed as large as possible in the geometry area. If your viewpoint of an part is extremely far away the display of the part will be very small (see Figure 13.10). Using the Fit All In command displays the part to fill the geometry area and thus it will appear the same as it

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did in Figure 13.09. Remember the size of the part did not change even though it appears larger because your viewpoint was just moved closer to it. There may be times that you lose a part in the 3D geometry area of CATIA. The Fit In All command allows you to quickly restore the display of a part so that you can change your orientation or distance from it.

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Figure 13.09 A Part Displayed After Fit All Command

Figure 13.10 A Part Displayed Very Small

PAN When the Pan command (see Figure 13.11) is used to change your viewing position it is moving your viewing position from either the left or right, above or below or a combination of these in relation to the part. Again, the position of the part does not change, only your viewing position relative to it changes. Figure 13.12 shows the viewpoint of the part being changed by the pan command. After the Pan Icon command is selected depress the left mouse button and notice a hand will appear in the geometry area. Keeping the left mouse button depressed allows the part to move around in the geometry area. Notice that the position of the part did not change in relation to the default sketch planes. Figure 13.13 shows the part panned to a different viewing position from Figure 13.12.

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Figure 13.11 Pan Icon

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Figure 13.12 Using the Pan Command

Figure 13.13 The Result of Panning the Part The mouse can also be used to turn on the Pan command. Depressing and holding the middle mouse button invokes the pan command. Notice the Pan icon appears in the geometry area when the middle mouse button is used for panning (see Figure 13.14). This is a much quicker way to use the pan command and it should be mastered and used in place of the Pan icon because you do not have to move your cursor from the geometry area.

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Figure 13.14 The Pan Icon Appears in the Geometry in Mouse Panning

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Figure 13.15 Rotate Icon

Figure 13.16 Initial Viewpoint

ROTATE The Rotate command (see Figure 13.15) is used to revolve your viewpoint position around the part. The position and orientation of the part is not changed only your viewing position has been revolved around the part, giving the impression that the part itself has been revolved. Figures 13.16 and 13.17 illustrate this concept when it appears that the object is being revolved. Actually you are moving yourself around to a different position relative to the object. Notice that the orientation of the object relative to the default sketch planes and the relationship to the compass did not change when the revolve command is used.

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Figure 13.17 Viewpoint After The Rotation Like the pan command the mouse can be used to rotate your viewpoint around a part. Depress and hold the middle mouse button and depress either the left or right mouse button to invoke the rotate command. A dashed circle representing the spherical coordinate system of revolution will appear (see Figure 13.18). Again, it is suggested that you master this technique because it will allow you to work faster.

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Figure 13.18 Spherical Coordinate System for Rotation

ZOOM IN The Zoom In command (see Figure 13.19) is used to allow a part to appear to be enlarged in the geometry area. What is actually occurring is that your viewpoint is getting closer to the part giving the impression that the part is actually increasing in size. This is a false impression because the size of the geometry is not changing. Figures 13.20 and 13.21 illustrate using the Zoom command to zoom in on a document. Each time that you click on the Zoom In icon you will incrementally move your viewpoint closer to it.

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Figure 13·19 Zoom In Icon

Figure 13.20 Initial Viewpoint

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Figure 13.21 Viewpoint After Zooming In The mouse can also be used for Zooming In to a document. Place you cursor toward the bottom of the geometry area and depress and hold the middle mouse button and tap and release either the left or right mouse button while still depressing the middle mouse button. Move the mouse up the geometry area and you will zoom in on the target area. Notice the mouse zoom is not incremental. The Zoom Out command (see Figure 13.22) works just the opposite of the Zoom In command in that your viewpoint relative to the document is further away thus making the document appear smaller in the geometry area. Using the Zoom Out command will move your viewpoint incrementally further away from the object.

Figure 13.22 Zoom Out lcon The mouse can also be used to zoom out from the object by placing your cursor toward the top of the geometry area. Next depress and hold the middle mouse button and tap and release either the left or right mouse button while still depressing the middle mouse button. This will turn on the mouse zoom.

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Figure 13.23 Zoom In Boundary Box

ZOOM AREA The Zoom Area command is only found under the View pull down menu. This command lets you define a zoom area by dragging with the left mouse button a rectangular boundary area on which you want to zoom in. The area inside the boundary box will be the area displayed in the geometry area of CATIA. This command is very useful when you want to quickly define a specific area to zoom in on for review. Figures 13.23 and 13.24 illustrate the use of the bounding box and the resulting view.

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Figure 13.24 Resulting View After the Boundary Zoom

NORMAL VIEW The Normal View Command (see Figure 13.25) allows you to get a normal (perpendicular) view of a selected surface. Many times this is important because you may need to view a surface in its normal position so that geometry or constraints can be added to it. Figure 13.26 shows the front surface of a part was selected with the Normal view command. Notice that the edges of the surface highlight and that the hand icon appears over the selected surface. Figure 13.27 shows the result of this surface being placed normal to your view point.

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Figure 13.25 Normal View Icon

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Figure 13.26 Surface Selected for Normal View

Figure 13.27 Resulting View After the Normal View Command

QUICK VIEWS TOOLBAR CATIA V5 has seven preset viewing positions that can be used to change your viewing position relative to a document. The Quick Views Toolbar allows you to use these preset viewing positions by allowing for the selection of seven different commands. Each Quick view command will be explained in the following paragraphs. Notice in Figure 13.28 that the Quick View toolbar has been undocked from the View toolbar.

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Figure 13.28 Undocked Quick View Toolbar

QUICK VIEW ICONS The Isometric View (see Figure 13.29) is the default quick view icon and it places your viewpoint in front of, to the left, and above the document. It gives you a pictorial representation of the document (see Figure 13.30).

Figure 13.29 Isometric View Icon

Figure 13.30 Isometric View of the Part The Front View option (see Figure 13.31) places your viewpoint directly in front of the document with your viewing direction normal to it. In your start part you named the yz plane as the frontal plane, thus the document will appear

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as in Figure 13.32 when the front view option is selected. In the front view the left to right and top to bottom dimensions are displayed. The Back View option (see Figure 13.33) is just the opposite of the front view in that your viewpoint is directly behind the document and your viewing direction is normal to it but the left to right and top to bottom dimensions will still be displayed.

Figure 13.31 Front View lcon

Figure 13.32 Front View of the Part

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Figure 13.33 Back View lcon The Left View (see Figure 13.34) and Right View options (see Figure 13.35) places your viewpoint either to the left of the part or to the right of it with your viewing direction normal to part from either the left or right side. In Figure 13.36, the Right view option was chosen and the resultant view of the part as viewed from the right is displayed. In your start part the xz profile plane is the sketch plane where the front to back and up to down dimensions will be displayed in either the left of right side views.

Figure 13.34 Left View Icon

Figure 13.35 Right View Icon

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Figure 13.36 Right View of the Part Finally, the Top View (see Figure 13.37) and the Bottom View (see Figure 13.38) options place your viewpoint either above or below the part and normal to it. In your startpart the xy plane is the horizontal sketch plane and the front to back and left to right dimensions will be displayed from either the top or bottom views. Figure 13.39 shows how the part would appear if you were viewing it from the top.

Figure 13.37 Top View lcon

Figure 13.38 Bottom View lcon

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Figure 13.39 Viewing the Part From the Top Both the Hide/Show and Swap Visible Space options will not be covered in this chapter. The View Mode Toolbar (see Figure 13.40) allows the part to be displayed in various ways. Many times you will want the entire part to be shaded for visibility reasons because it would be easier to understand. Other times the part may be so complex and large that the workstation cannot handle fully shading it. The following paragraphs will cover each option from the View Mode Toolbar.

Figure 13.40 View Toolbar Figure 13.41 Wire (NHR) lcon The Wireframe display mode (see Figure 13.41) displays all lines and vertices of the part (see Figure 13.42). Wire frame mode for display is typically used when very large parts are needed to be viewed and worked on in CATIA V5. Because these parts are very large their response time is very slow. Wireframe mode may be the only display mode that allows you to work with the part. The drawback of wireframe mode is that it is the hardest mode for you to visualize a document because all of the lines and vertices are displayed.

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Figure 13.42 Part Displayed as Wirefmme Dynamic Hidden Line Removal (see Figure 13.43) still shows the document as wireframe and not shaded but all the lines hidden behind the surfaces closest to you will not be displayed. Dynamic Hidden Line allows for better visualization and in most instances good performance (see Figure 13.44).

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Figure 13.43 Dynamic Hidden Line Removal Icon

Figure 13.44 Part Displayed as Dynamic Hidden Line Removal Icon The Shading (see Figure 13.45) shades all surfaces of a document. The advantage to using shading is that documents are much easier to visualize. The drawback of using shading for display is slower response time while working with the model (see Figure 13.46).

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Figure 13.45 Shading (SHD) lcon

Figure 13.46 Part Displayed as Shaded Shading With Edges (see Figure 13.47) works like a combination of the dynamic hidden line removal with shading applied, thus the edge of every of a document has lines and every surface is shaded. It is easier for visualization but can be a display problem for complex documents (see Figure 13.48)

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Figure 13.47 Shading With Edges Icon

Figure 13.48 Part Displayed as Figure 13.49 Shaded With Edges Shaded With Edges and Hidden Edges lcon Shading With Edges and Hidden Edges (see Figure 13.49) is identical to Shading With Edges except the edges or intersections of hidden surfaces are displayed with dashed lines. It is very good for visualization but again may present problems if a part is very large or complex (see Figure 13.50).

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Figure 13.50 Part Displayed as Shaded With Edges and Hidden Edges Applies Customized View Parameters (see Figure 13.51) allows you to customize your own view by applying different view parameters. This will not be covered.

Figure 13.51 Applies Customized View Parameters Icon

EXERCISE 13.1 In this exercise you will load a sample CATpart document and practice using the mouse button combinations to pan, rotate and zoom in/out on a model. As explained earlier, these actions can either be carried out by using the icons on the View toolbar or by using the mouse. As you become more comfortable and experienced with CATIA, you will see that using the mouse for basic viewing operations is a great time saver. Therefore it is suggested that you get as familiar as you can with using these combinations. Perform View operations on a sample part. 1. Open the CATIA file named Sample1 and save it as the correct assignment number. 2. Depress the middle mouse button and move the mouse around while holding the button down. 3. You will see the model pan or move around the three-dimensional geometry area. It does not matter where you click in the geometry area to perform the pan operation. 4. Next step, depress and hold the middle mouse button once more and this time press either the left or right mouse button also. A dashed orange circle will appear around the model. Notice that the cursor changes to a hand symbol. Move the mouse around to rotate your viewpoint of the model in 3D space. 5. Learn the difference between starting the rotate command with the cursor inside the dashed circle, compared to when you move with the cursor outside the circle.

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6. Now try zooming in and out of the model. Follow the steps as described in step 4. Only this time, release the left/right mouse button but keep the middle button pressed. 7. Move the mouse up to zoom in and down to zoom out. 8. Practice quick switching between the pan, zoom and rotate operations by coordinating the mouse button presses. 9. As a further exercise, try and discover another way of using the three view commands using keyboard and mouse combinations. Hint: Use just the CTRL key and middle mouse button. It's possible to carry out all 3 operations.

EXERCISE 13.2 This exercise will step you through usage of the visualization tools of CATIA. 1. Open the CATIA file named Sample1 and save it as the correct assignment number (see Figure 13.52).

Figure 13.52 Sample Part 1 2. Switch to the Part Design workbench if you have not already done so. 3. Click on the Fit All in icon to make sure the complete geometry is visible on the screen.

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4. Next, switch to a pictorial view of the model by clicking on the Isometric view icon. 5. Now click on the small black arrow next to the Isometric view icon (see Figure 13.53) and cycle through the different views. Notice how the model appears to rotate in space to orient to the new view.

Figure 13.53 Isometric View Icon

Figure 13.54 View Mode Toolbar

6. Return to the isometric view. 7. Click on the Normal View icon and then click anywhere on the top surface of the model. 8. The model will rotate to a position where the top surface becomes parallel to the screen. 9. Return to the isometric view. 10. Now try the various shading options available in the View Mode toolbar (see Figure 13.54). 11. You will find it useful to switch between wireframe and surface modes to get a better look at complex models. 12. For more practice, you can experiment with the CATpart Sample2. Do not save this file as an assignment. It is solely for practice purposes (see Figure 13.55).

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Figure 13.55 Sample part 2

SUMMARY This chapter gave you an overview of CATIA and the different workbenches and terminology that will be covered in this text. It also presented different file formats that CATIA generates from the various workbenches. Visualization was defined as the viewer's position relative to an object and stressed that orientation or the location of the geometry does not change when your view of a part or feature is changed but rather your position relative to the part or feature changes. The different viewing tools available in CATIA that allow you to change your view of the geometry or the display of geometry were explained.

14 CREATING SKETCHED GEOMETRY INTRODUCTION In chapters one and two the CATIA interface was introduced and the concept of workbenches was covered. Chapter three presents a comprehensive coverage of geometric entities. It will also go into greater detail on the use of both geometric and dimensional constraints and how to use additional geometry editing commands. OBJECTIVES After completing this chapter you will be able to: 1. Enter the sketcher mode. 2. Use any of the sketching tools within the profile toolbar. 3. Learn to use the grid to construct dimensionless sketches. 4. Understand the difference between standard and construction geometry. 5. Change line types of sketched geometry. 6. Perfon11 editing operations such as trimming. 7. Describe and apply geometric and dimensional constraints.

ENTERING SKETCHER MODE The sketcher mode can be found within the Part Design workbench. Start the design workbench and click on the sketcher icon (see Figure 14.01) and then select one of the sketching planes (see Figure 14.02) to enter the sketcher mode.

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You can also select a sketch plane first and then click on the sketcher icon. Later on, you will see how surfaces of 3D objects can be used as sketching planes. Notice that the toolbars to the right of the geometry have changed and now contain construction, editing and transformation tools. Let's take a closer look at each tool.

Figure 14.01 Sketcher icon

Figure 14.02 Sketching planes

2D GEOMETRY In CATIA solid geometry is developed through the use of a 2D sketcher. There are several different 2D geometry commands available to develop sketched geometry. Different 2D geometry commands will be covered in the following paragraphs. Not all of these 2D geometry commands will be covered in detail. You are encouraged to work with the commands so you can easily locate and apply them when needed. The Profile toolbar contains most of the 2D geometry commands that are needed to construct sketched geometry (see Figure 14.03). The first icon located on the left end of the Profile toolbar is the Profile Tool. The profile tool allows you to construct both lines and arcs as a continuous entity. Move the cursor anywhere in the drawing area and click the left mouse button. A line segment will be started. Clicking again will end the first line segment and start a new line. You will continue making new line segments until you press another command, hit the escape key, double click on the endpoint of the last line segment, or

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connect the end of the first line segment to form a closed boundary. Any of these actions will close the line segment command of the profile tool. The profile tool also allows you to create arcs at the end of an existing line segment. To create the arc at the second end of a line segment the first end of the line segment is started as normal by clicking to start the line segment with the left mouse button. To create an arc at the opposite end of the line segment you click on the second end of the line segment with the left mouse button hold and drag the mouse any desired distance to form the arc. Arcs can also be started from the end of an existing arc by clicking the left mouse button and dragging it to the desired distance to form the arc. Figure 14.04 shows the construction of an arc from an existing line segment. The profile tool is a very powerful 2D construction tool, and it should be used extensively when sketched geometry is being constructed.

Figure 14.03 The Profile Toolbar

Figure 14.04 Constructing an Arc Using the Profile Tool The Predefined Profile toolbar is located directly to right of the profile tool on the profile toolbar. The default entity for this tool is a Rectangle. All of the options available are predefined shapes that could be commonly used in the development of sketched geometry. These include: the Orientated Rectangle, Parallelogram, Elongated Hole, Cylindrical Elongated Hole, Keyhole Profile, and Hexagon. The predetermined profiles can be modified by grabbing

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different parts of the geometry with the cursor and moving entities around. Figure 14.05 shows the Predefined Profile toolbar detached from the profile toolbar in a landscape orientation and sketches of each geometric option.

Figure 14.05 The Predetermined Profile Toolbar The Circle toolbar includes the Circle, Three Point Circle, Circle Using Coordinates, Tri-Tangent Circle, Three Point Arc, Three Point Arc Staring With Limits, and Arc tools (see Figure 14.06 ) .

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Figure 14.06 The Circle Toolbar The Spline toolbar has two options, the Spline tool and the Connect option (see Figure 14.07).

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Figure 14.07 The Spline Toolbar The Conic toolbar has the following options; Ellipse, Parabola by Focus, Hyperbola by Focus, and Creates a Conic (see Figure 14.08).

Figure 14.08 The Conic Toolbar The Line toolbar has the following options: Line, Infinite Line, Bi-Tangent Line, and the Bisecting Line (see Figure 14.09).

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Figure 14.09 The Line Toolbar The Axis tool is also located on the Profile toolbar. Axes are needed for specific operations such as revolutions (see Figure 14.10).

Figure 14.10 The Axis Tool

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The Point toolbar has the following options: Point By Clicking, Point by Using Coordinates, Equidistant Points, Intersection Point, and Projection Point (see Figure 14.11).

Figure 14.11 The Point Toolbar The Sketch Tools toolbar is shown in Figure 14.12. It is a contextual toolbar which means that additional options become available as different commands are selected. The Sketch Tools toolbar contains the Snap to Point, Construction/Standard Elements, Geometrical Constraints, and Dimensional Constraints. Always leave the Geometrical and Dimensional constraints options off. This will be discussed later. The Snap to Point option allows the cursor to either move freely in the sketcher or to the grip points. Because sketches do not have to be dimensionally correct when they are sketched it is good practice to leave the Snap to Point option turned off. The Construction/Standard Elements option allows geometric elements to be constructed as either standard geometry or construction geometry. Typically, construction geometry is used to help locate geometry with either geometric or dimensional constraints. If the Construction/Standard Elements is activated it

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will appear in orange and all resultant geometry will be represented by dashed lines. If an existing geometric entity needs to be changed to construction geometry, select the desired geometry and then select Construction/Standard Elements. This will turn geometry into construction geometry. Likewise, construction geometry can be changed to standard geometry by selecting the Construction/Standard Elements option (see Figure 14.13).

Figure 14·12 The Sketch Tools Toolbar

Figure 14.13 Construction/Standard Elements

EDITING OPERATIONS CATIA has several operations that allow 2D sketched geometry to be created or edited. These commands are located on the Operations toolbar (see Figure 14.14). There are several Operation commands, but only a few of them will be demonstrated with the following examples. The Relimitations toolbar is located on the Operations toolbar and it contains tools that allow geometry to be trimmed from, or extended to, other geometry. In the following examples, the first figure is the given geometry, and the second figure is the resultant geometry after the lines have been trimmed. When you

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use the Trim command you select on the geometry that you want to keep. Any geometry on the other side of the intersection of the geometry will be deleted (see Figure 14.15). Note that there must be intersecting geometry in order for the Trim command to function. The Trim command will also extend geometry to other geometry. Pick on the geometric entity you want to extend and the entity that you want it extended to as shown in Figure 14.16.

Figure 14.14 Operations Toolbar

Figure 14.15 Relimitations Toolbar.

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Figure 14.16 Using the Trim command to Extend Geometry The Quick Trim command works just the opposite of the Trim command. What you select will be the portion of the geometry that will be deleted (see Figure 14.17).

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Figure 14.17 Using the Quick Trim command to Delete Geometry The Symmetry command allows geometry to be mirrored around a specified line. In Figure 14.18, the Symmetry command was used to create the second circle on the right side of the given line. The circle was picked as the entity to be mirrored. The line shown is the line of symmetry that the circle is mirrored around for the required geometric construction.

Figure 14.18 Using the Symmetry Command Allows Geometry to be Mirrored CONSTRAINTS Constraints are used to force geometry to a certain size, control its location, or have it interact with other geometry for location or orientation purposes. There are two types of constraints: Geometric and Dimensional.

GEOMETRIC CONSTRAINTS The following examples will illustrate geometric constraints and how they are manually applied. Constraints are located on the Constraint toolbar (see Figure 14.19). The Constraint, the Auto Constraint, and the Animate Constraint are the constraint options available from the Constraint toolbar. Throughout most

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of this book Automatic Constraints will not be demonstrated because they are difficult to work with until you have a thorough understanding of the use of manual constraints. To apply constraints, double click on the constraint icon. If you are placing a constraint on a single entity, select that entity with the left mouse button and click with the right mouse button to select the desired constraint. In Figure 14.20 there is a given line. The Horizontal constraint is used to orient the given line into a horizontal orientation. 1. Double click on the constraint icon and pick the first line with the left mouse button. 2. After the dimension appears pick the right mouse button to make the pop-up menu appear. 3. Select the Horizontal option from the pop-up menu and the line will be horizontally orientated. Note that an "H" will appear on the line depicting the applied horizontal constraint. This same procedure can be used to orientate a line vertically with the Vertical constraint.

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Figure 14.19 The Figure 14.20 Applying a Horizontal Constraint Toolbar Constraint to a Line The Concentric constraint is used to make circles and arcs concentric with each other. In Figure 14.21, the two circles need to be concentric. 1. Double click on the constraint icon and pick with the left mouse button the circle that you want to remain in the same position. 2. Select the second circle with the left mouse button. 3. After the dimension appears, pick the right mouse button to activate the pop-up menu. 4. Select the Concentric option from the pop-up menu and the circles will be concentric to each other. Note that the second circle picked is the circle that will be moved to the concentric position and that the concentric icon appears denoting that the circles are concentric. Endpoints of lines and the centers of arcs or circles can likewise be made concentric using a Concentric constraint.

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Figure 14.21 Applying a Concentric Constraint to Two Circles The Tangent constraint is use d to make circles, arcs, and lines tangent. Figure 14.22 illustrates tangency constraints between a line and a circle and between two circles. Tangency constraints between lines and arcs function the same as tangency constraints between line s and circles. 1. Double click on the constraint icon and pick with the left mouse button the geometric entity that you want to remain in the same position. In this example the circle was selected. 2. Again, with the left mouse button, select the line. 3. After the dimension appears, pick the right mouse button to activate the pop-up menu. 4. Select the Tangent option from the pop-up menu and the line will be tangent to the circle. Note: the circle remained stationary and the line move s to a tangent position because the circle was chosen first. Also note, the line does

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not have to intersect the circle to make it in a tangent orientation relative to the circle. 5. In the second example, the smaller circle was selected first thus causing the larger circle move to the tangent position.

Figure 14.22 Applying Tangent Constraints The Coincidence constraint is used to make entities share one point. Figure 14.23 illustrates using coincidence constraints to locate the circle to the intersection of a construction circle (bolt circle) and an angled construction line. 1. Double click on the constraint icon and pick with the left mouse button the construction circle and then with a second pick the center point of .25R circle. 2. After the dimension appears pick the right mouse button to activate the popup menu. 3. Select the Coincidence option from the pop-up menu. 4. This forces the center point of the .25R circle to fall on the construction circle.

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5. Repeat this procedure again by selecting on the angled construction line and the center of the .25R circle. 6. The center point of the .25R circle is coincidental with both the circular construction line and the angled construction line, thus the center point of the .25R circle will be forced to the intersection of the construction circle and angled construction line. The Coincidence constraint can also be used to make geometry lie directly on top of geometry. Thus two lines or other identical geometric entities can be forced to lie directly on top of each other by using a coincidence constraint.

Figure 14.23 Applying Coincidence Constraints The Parallel and Distance constraints are used to make parallel lines. Figure 14.24 illustrates parallel constraints between two lines. 1. Double click on the constraint icon and pick with the left mouse button the geometric entity that you want to remain in the same position. In this example the left line was selected. 2. Again with the left mouse button, select the right line. 3. After the dimension appears, pick the right mouse button to activate the pop-up menu.

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4. Select the Parallel option from the pop-up menu and the second line will be parallel to the first line. Note that the parallel symbol appears. The Distance constraint functions identically to the parallel constraint except a dimensional constraint is also included with the parallel constraint. This allows a specific distance between two parallel lines to be determined. In Figure 14.24, the bottom example uses a distance constraint of 2. Remember the shortest distance between two lines is a line perpendicular to both lines, thus the lines must be parallel to each other.

Figure 14.24 Applying Parallel and Distance Constraints The Perpendicular constraint is used to make lines perpendicular to each other. Figure 14.25 illustrates the Perpendicular constraint between two lines. 1. Double click on the constraint icon and pick with the left mouse button the geometric entity that you want to remain in the same position. In this example, the left line was selected. 2. Again with the left mouse button, select the right line. 3. After the dimension appears, pick the right mouse button to activate the pop-up menu.

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4. Select the Perpendicular option from the pop-up menu and the second line will be perpendicular to the first line. Note that the perpendicular symbol appears. Also, note that the lines do not have to intersect to be perpendicular with each other.

Figure 14.25 Applying Perpendicular and Distance Constraints The Midpoint constraint is used to make geometric entities constrained to the center of the line segments. Figure 14 .26 illustrates how the Midpoint constraint can be used to locate the center of a circle to the midpoint of a line. 1. Double click on the constraint icon and pick with the left mouse button either the line or the center of the circle. 2. Again with the left mouse button, select the other entity. 3. After the dimension appears, pick the right mouse button to activate the pop-up menu.

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4. Select the Midpoint option from the pop-up menu and the center point of the circle will move to the Midpoint of the line. If the line segment increases or decreases in length the center point of the circle will always remain on the Midpoint of the line. 5. This same procedure can be used to constrain the endpoint of a line to the midpoint of a second line.

Figure 14.26 Applying a Midpoint Constraint

DIMENSIONAL CONSTRAINTS Dimensional constraints are used to size and to locate geometry. Dimensional constraints must be added to geometry after all geometric constraints, because geometric constraints control the shape of the geometry. Dimensional constraints are placed on a sketch by double clicking on the constraint tool and then picking the geometric entity with the left mouse button, moving it to the desired location, and placing it by again clicking the left mouse button. Figure

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14.27 contains several size dimensional constraints including the 1.5 height, 2.5 widths, .5 circle diameter, and 1 radius arc. It also includes .5 width and .8 height dimensions locating the center of the circle.

Figure 14.27 Dimensional Constraints The default dimensional sizes can be changed by double clicking on the constraint dimension number and entering a new number in Value field of the Constraint Definition dialog box (see Figure 14.28).

Figure 14.28 Constraint Definition Dialog Box

EXERCISE 14.1 In this exercise, you will create a simple two-dimensional geometrical shape. You will only use tools within the Profile Toolbar. There are no dimensions

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given to this sketch and you will use the grid intersection points to help you with positioning your sketch boundaries. 1. Open your startpart file and save it as the correct assignment number. 2. Click on the XY plane and then on the sketcher icon. 3. The view should rotate to an angle normal to the XY plane and a grid should appear. 4. Mirror these settings on your Sketch Tools toolbar. (See Figure 14.29) Snap to Point- ON Construction/Standard Element - OFF Geometrical Constraints- OFF Dimensional Constraints- OFF Note: When the icon is highlighted in orange, this means it's turned ON.

Figure 14.29 Sketch Tools settings

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Figure 14.30 Sketched geometry 5. Recreate Figure 14.30 using any of the icons within the Profile Toolbar (see Figure 14.31).

Figure 14.31 Profile Toolbar

6. To construct the center lines for the circles, use the Line tool and turn on Construction/Standard Elements before making a line. 7. Note that the line running horizontally through the center of the sketch is also a construction line. 8. You can also toggle between construction and standard line types by selecting any sketch and clicking on the Construction/Standard Elements icon. 9. The default line type for construction lines in CATIA is different from what we use as centerlines. Though we want the centerlines in our sketch to remain construction geometry, we would still like to change the line type to a centerline. 10. To do so, first select all the centerlines. You can select multiples by keeping the CTRL key pressed. 11. After all the lines are highlighted, right click on Properties. (See Figure 14.32) 12. Select the Graphic Tab and under the Lines and Curves option, change the Line type from the default type 3 to type 7. (See Figure 14.33) This is a more accurate representation of a centerline.

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Figure 14.32 Right Figure 14.33 Line type settings click menu 13. Exit out of the dialog box by clicking on Ok and you should be able to see your changes. 14. Save your file.

EXERCISE 14.2 In this exercise, you will first create a sketch of the Olympic rings and then use the trim operation to overlap the rings. The settings for this exercise will remain the san1e as the exercise 14.1 and you will not be using dimensions to size the geometry. 1. Open your startpart file and save it as the correct file name. 2. Click on the XY (Horizontal) plane and then on the sketcher icon.

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3. The view should rotate to an angle normal to the XY (Horizontal) plane and a grid should appear. 4. Mirror these settings on your Sketch Tools toolbar. (See Figure 14.34)

Figure 14.34 Sketch Tools settings 5. Recreate Figure 14.35 by using any of the icons within the Profile Toolbar. (Hint: It is helpful to zoom out a little before creating the rings, so use a smaller grid size). 6. The next step is to trim out all the unwanted arcs of the circles.

Figure 14.35 Sketched geometry Olympic Rings 7. Use either the Trim or Quick Trim command to recreate the Figure 14.36. Read the next two points for hints.

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8. While performing the Trim operation, small green circles might appear near the sketched geometry. These are automatic constraints applied by CATIA and need not be bothered with for now.

Figure 14.36 Finished geometry 9. Be careful while using the Trim command. At times, a trim operation will not have the desired effect. In such a case, Undo the last command and try another method. Also, keep a close eye on the geometry while editing it. Make sure no other part of the geometry is moved or edited by mistake. 10. Save your file once complete.

EXERCISE 14.3 3D geometry in CATIA like most other 3D CAD packages is initially constructed on a 2D surface. This exercise will give you a brief overview of the CATIA sketcher interface and expose you to a few very basic geometry commands. You will then continue and perform a few editing operations and finally use constraints on the sketch. The last step will be an introduction to creating 3D geometry from the sketch. 1. Load your startpart file and save it as the correct assignment.

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2. Pick either the XY plane (horizontal) in the specification tree or select directly on the plane. 3. Pick the Sketcher command that is located near the top, right side of the list of commands on the screen (see Figure 14.37). This procedure determines the sketch plane. 4. The screen will appear entirely different from the default CATIA interface. 5. A 2D grid will cover the entire geometry area of CATIA. 6. Locate the profile toolbar, which is used for the creation of 2D geometry, and drag it into the drawing area. Move this toolbar to the top of the screen and dock it with the other toolbars located across the screen and then move it back into the drawing area (see Figure 14.38). Docking toolbars to the top of the screen allows them to appear in landscape orientation. This also allows the name of the toolbar to be displayed thus helping in its identification. The profile tool allows for the creation of 2D geometrical entities.

Figure 14.37 The Sketcher Figure 14.38 The Profile Toolbar icon 7. Refer to Figure 14.39 and use the rectangle, circle, and line commands from the profile toolbar to construct a figure similar to Figure 14.39.

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Figure 14.39 Creating Geometry with the Circle, Line, and Recrangle Profile Commands 8. Locate the Constraint Toolbar and lock it to the top of the screen, and move it into the drawing area (see Figure 14.40). One of the tools in the operation toolbar is the Constraint tool. The constraint tool allows either geometric or dimensional constraints to be added to 2D geometry.

Figure 14.40 The Constraint Toolbar 9. In this example, double click on the constraint command. Double clicking on any command keeps the command active until the current command is clicked once, or another command is started, or the escape key is pressed twice. 10. In the first example select the left end line of the rectangle and the left side of the lower left-hand circle with the left mouse button. After picking the circle do not click with the left mouse button because this will place a dimensional constraint between the rectangle and the circle. Notice that a dimension appears. 11. Click with the right mouse button. A pop-up menu will appear. 12. Select the tangency option. This will place a tangency constraint that makes the circle tangent to the rectangle. Since the rectangle was the first entity chosen it remains stationary and the circle moves to become tangent to the rectangle (see Figure 14.41). Note that a tangency constraint symbol appears on the circle. 13. Use this same procedure to make the top right circle tangent to the rectangle and the skewed line tangent to both circles. Your figure should appear similar to Figure 14.42, when all of the tangency constraints have been added.

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14. Locate the Operation Toolbar and lock it to the top of the screen and move it into the drawing area (see Figure 14.43). One of the tools in the operation toolbar is the Trim tool.

Figure 14.41 Constraining the Circle to the Rectangle

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Figure 14.42 Completed Figure After All Tangency Constraints Were Added

Figure 14.43 The Trim Command is Located in the Operation Toolbar The trim tool allows geometrical entities to be trimmed by or extended to other geometries. 15. Use the trim tool to edit the existing geometry by clicking twice on the trim option with the left mouse button. 16. Use the cursor to select the left-hand line of the rectangle and the lower left side of the circle. Your figure should look similar to Figure 14.44 when you are completed trimming these entities.

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Figure 14.44 Extending the Line from the Rectangle Tangent to and Trimming the Circle 17. Use the same techniques to trim and extend all of these entities (see Figure 14.45). 18. Turn o ff the trim command by clicking on it once.

Figure 14.45 Completed Trims 19. Depress the Ctrl key and select the bottom and right-hand lines of the rectangle. Then hit the Delete key to remove these lines. Your figure should appear similar to Figure 14.46 when it is completed. 20. Save this file with the correct file name.

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Figure 14.46 Deleting the Two Lines of the Rectangle to Complete the Sketch

EXERCISE 14.4 In this exercise, you will access an existing file and use geometric constraints and editing commands to make a sketch of the object. This assignment is very similar to exercise 14.3, thus suggested commands and steps will be presented, but not in a step-by-step sequence as was done with exercise 14.3. 1. Open the file named tan&trim (see Figure 14.47).

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Figure 14.47 The tan&trim exercise 2. In the Specification tree expand the "PartBody" by clicking on the"+" and double click on "Sketch.1". 3. Use geometric constraints to make the entire outside lines tangent to the given circles. The constraint tool is located on the constraint toolbar. Remember to double click on the constraint icon and then select one of the geometric entities with the left mouse button, then select the second entity with the left mouse button as well. Once a dimension number appears click the right mouse button and select the tangency option from the pop-up menu. Because the circles are constrained, or located, with dimensional constraints the lines were forced to move to be tangent with the circles. Even if you had selected the lines first when you were making them tangent

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to the circle the lines would still move. Had the circles not been constrained and you would have picked the line first, the circles would have become tangent to the lines thus causing their diameter to increase. Your sketch should appear identical to Figure 14.48.

Figure 14.48 Lines Constrained to the Circles with Tangency Constraints

USING TRIM FEATURE 1. Use the trim command t o trim away the ends o f the lines and the unneeded portions of the circles. Remember the trim command is located in the operations toolbar and that you want to select the portion of the circle or line that you want to keep when these entities are trimmed. Zooming in on the specific areas where the trims are to be completed first makes trim

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operations easier. Once the trim commands are completed your figure should appear identical to Figure 14.49.

Figure 14.49 The Results of Using the Trim Command 2. Save your sketch. 3. Now exit the sketcher workbench by selecting the Exit workbench icon (see Figure 14.50) from the Workbench toolbar, which is typically docked on the upper right side of the CATIA interface.

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Figure 14.50 The Exit workbench lcon After you exit the sketcher workbench, CATIA will change into the Part Design Workbench. Notice how the sketcher grid not longer appears and the toolbars and associated icons are different. In CATIA, as you change from one workbench to another one the interface will change because there are specific toolbars and icons for each individual workbench.

CREATING A SOLID FEATURE The next steps will illustrate how sketches can be turned into solid geometry features. 1. Expand the Part Body feature on the specification tree by clicking on the +icon. Notice that a sketch feature will appear below the Part Body feature. 2. Select the sketch feature with you left mouse button. Once the sketch feature is selected the entire sketch should appear highlighted in red. 3. Locate the Sketch-Based Features toolbar. The commands on this toolbar allow sketch geometry to be turned into 3D solid geometry. The Pad button on this toolbar will change the sketch geometry into linear extruded geometry. 4. Double click on the Pad icon and the Pad Definition dialog box appears (see Figure 14.51). The Pad Definition dialog box allows you to configure and define the pad. Look at the different options available for defining pads. 5. For this example accept the Pad Definition dialog box defaults by selecting OK or hitting the enter key. Your geometrical object should appear similar to Figure 14.52.

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Figure 14.51 The Pad Definition Dialog Box

Figure 14.52 The Resultant Solid Part

EXERCISE 14.5

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In this exercise, you will be given applied experiences on using circles, lines and both geometric and dimensional constraints to construct the 2D sketch of this part. The 2D sketch will then be extruded into 3D solid geometry.

SKETCHING THE THREE CONCENTRIC CIRCLES 1. Open your CATIA file named startpart and save it as the correct assignment number. 2. Make certain that your units of measure are set to Inch (in). 3. Pick the xy plane (horizontal) in the specification tree. It should be highlighted. 4. Pick the Sketcher icon from the sketcher toolbar (see Figure 14.53)

Figure 14.53 The Sketcher Icon 5. From the Profile toolbar choose the Circle option and sketch a circle above and to the right of the default datum planes. Do not worry about its size. 6. Sketch a second and third circle in the immediate location of the first circle. Your circles could appear similar to Figure 14.54.

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Figure 14.54 The Three Sketched Circles 7. Locate the Sketcher Tools Toolbar and pick the Construction/Standard Element option (see Figure 14.55).

Figure 14.55 Sketcher Tools Toolbar 8. Select two of the circles by picking with the mouse button while depressing the Ctrl key. Notice that the selected circles change from solid circles to dashed circles. The dashed circles are no longer standard circles but are construction circles. Construction geometry is used in the development of sketches in that it acts as a geometric construction aid and is not recognized as standard geometry by CATIA (see Figure 14.56).

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Figure 14.56 Two Construction Circles and the Standard Circle USING DIMENSIONAL CONSTRAINTS TO LOCATE THE CONSTRUCTION CIRCLE 9. Double click on the Constraint icon to make it active. 10. Pick the center of the construction circle, the horizontal axis line, and place the dimension. Repeat this again by selecting the center of the construction circle and the vertical axis line and place the dimension. The location of these dimensional constraints is not critical. Change the dimensional constraint values to two by double clicking on the given dimensional values and changing them. Your skcetch should appear similar to Figure 14.57.

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Figure 14.57 The Dimensionally Constrained Construction Circle It is good modeling practice to use dimensional constraints to control the location of sketched geometry from a desired location on a part or from the world coordinate position of 0,0,0. This allows the model to be moved to a new location by just changing the dimensional values. In this problem, once all of the sketched geometry is constructed both of the dimensional values of four will be changed to zero; thus, the sketch will be located at the world coordinate location of 0,0,0. Had one of the circles been sketched initially at the world 0,0,0, it would be more difficult to move the geometry from this location if it had to be moved at a later time.

USING GEOMETRIC CONSTRAINTS TO MAKE ALL THREE CIRCLES CONCENTRIC

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11. Activate the Constraint command by double clicking on it if it was deactivated. 12. Select the dimensionally constrained construction circle with the left mouse button and the remaining construction circle with the left mouse button. 13. When the dimension value appears click the right mouse button and select the Concentricity option from the pop-up window. 14. Repeat this procedure for the other standard circle to locate it. (see Figure 14.58).

Figure 14.58 Using Geometric Constraints to Locate the Concentric Circles

USING DIMENSIONAL CONSTRAINT TO SIZE THE THREE CIRCLES 15. Apply a dimensional constraint to the standard circle by clicking in it with the left mouse button. Place the dimension by clicking on the mouse button once more.

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16. Repeat this procedure and give dimensional constraints to both construction circles. 17. To turn off the constraint command, click on it with the left mouse button. 18. Double click on the dimensional value of the standard circle. The Constraint Definition dialog box will appear. In the Dimension field, make sure it is set to Diameter then enter 4 and select OK (see Figure 14.59).

Figure 14.59 Constraint Definition Dialog Box 19. Repeat this procedure to change the size of the smaller construction circle to a diameter of 3.5 and the larger construction circle to a diameter of 5. Your sketch should appear identical to Figure 14.60.

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Figure 14.60 Dimensionally Constrained Concentric Circles

DETEMIINING IF THE SKETCH IS A VALID SOLID Once a major milestone in the construction of a sketch is achieved, it is good practice to determine if the sketched geometry can be converted to solid geometry. If the sketched geometry converts into solid geometry, you do not have any problems, but if a sketch will not convert into 3D solid geometry, the problem with the sketch should be located and fixed. Finding errors in sketches are easier when the sketch is not complicated and is done in steps. The more complicated the sketch, the harder it becomes to locate errors in it. The next few steps will show you how to take the sketched geometry and turn it into extruded solid geometry with the Pad command.

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20. Select the Exit workbench option (see Figure 14. 61) to exit the sketcher. 21. Expand the PartBody in the specification tree and select Sketch1. 22. Select the Pad option from the Sketch-Based Features toolbar. (see Figure 14.62) 23. The Pad Definition dialog box will appear (see Figure 14.63).

Figure 14.61 The Figure 14.62 The Figure 14.63 The Pad Exit workbench Pad Tool lcon Definition Dialog Box Icon 24. Accept the default values by picking OK. If the 2D sketch is valid it should extrude into a solid part (see Figure 14.64). If the 2D sketch is not valid, the Pad command will not allow the 2D geometry to be extruded into 3D solid geometry. The most common causes of invalid 2D sketch geometry are, the 2D geometries are not completely closed, are overlapping, or are intersecting each other in the sketch. As you get more experience using CATIA you will be able to identify where there are problems in 2D sketches.

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Figure 14.64 Cylinder Created as a Pad CONSTRUCTING THE LEFT BACK LUG The following steps will illustrate how the left back lug of the bench gasket is to be constructed. 25. In the specification tree select Sketch.1 under the PartBody/Pad.1 branch to access the sketch for Pad.1. Notice that CATIA is in the Sketch workbench. 26. From the Profile toolbar select the Axis tool (see Figure 14.65) and add four center lines to the sketch. Make certain the starting point of each axis line is coincidental to the center of the circles. A solid circle with a concentric circle surrounding it means the points (end of the axis and the center of the circle in this case) are coincidental.

Figure 14.65 The Axis Tool Icon 27. Use geometric constraints to make two of these lines vertical and the other two lines horizontal (see Figure 14.66).

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Figure 14.66 The Horizontal and Vertical Axis Lines When CATIA is in the sketch workbench the default sketch view is normal to the sketch plane and absolute axes are labeled "V" for the vertical axis and "H" for the horizontal axis. With circular or cylindrical geometry it can be difficult to visualize where a geometric entity will be located once the geometry is viewed from the 3D pictorial (isometric) viewpoint. Once CATIA is in the default sketch view it can be helpful to change the viewpoint to the isometric view to locate the geometry in its correct location. 28. From the View toolbar select the Isometric view icon from the Quick view toolbar (see Figure 14.67). The sketch view is now an isometric view.

Figure 14.67 Isometric View Icon 29. Place a circle generally to the left and back of the existing concentric circles (see Figure 14.68).

Figure 14.68 The Circle Added to the Sketch in the Isometric View 30. Select the Normal View icon from the View toolbar so that your view of the sketch is now perpendicular (see Figure 14.69).

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Figure 14.69 Normal View Icon NOTE: for some individuals it is easier to work on sketches from an isometric view. Using either the normal or isometric viewpoints will end up with the same results if the sketch is constructed properly. Many times it is advantageous from a visualization standpoint to use both the isometric and normal views to construct sketched geometry. 31. Use coincidental constraints to locate the center of the non-dimensioned standard circle coincidental to the five diameter construction circle and to the bottom vertical construction line. 32. Use a dimensional constraint to size the non-dimensioned standard circle to a diameter of .75. 33. Add two standard lines to the sketch and use geometric constraints to make them vertical and tangent to the .75 diameter circle (see Figure 14.70).

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Figure 14.70 The Two Standard Geometrically Constrained Lines Added to the Lug 34. Use the Trim and Quick Trim commands from the Relimitations toolbar to trim the lug (see Figure 14.71). With the Quick Trim command the portion of the geometry that is selected will be deleted. With the Trim command the portion of the geometry will be kept.

Figure 14.71 The Quick Trim Icon 35. Your sketch should appear similar to Figure 14.72.

Figure 14.72 Using the Trim and Quick Trim Commands t o Complete the Lug 36. Exit the sketcher to verify if the back left lug was constructed correctly.

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37. Add two Axis lines to the sketch. Make certain that one end of the line is coincidental to the center point of the base construction circle. 38. Use dimensional constraints t o locate each lug center line at 120 degrees from the vertical center line of the existing lug (see Figure 14.73).

Figure 14.73 The 120 Degree Constrained Axis Lines Added to the Vise Gasket NOTE: A formula was used to make one of the angles equal to the other. By double clicking on the number of any dimensional constraint and replacing the number with an "=" sign then specifying a parent dimension allows formulas to be used to with dimensional constraints. 39. Add the necessary standard and construction geometry and the required constraints and trims to complete the remaining lugs of the vise gasket. Use parallel constraints to orientate the standard lines of these two lugs parallel to the 120 degree axis lines (see Figure 14.74). NOTE: When the diameter four circles are trimmed only one of the three arc segments is constrained. Use coincidence two constraints t o locate the two unconstrained arcs equal to the constrained four diameter arc.

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NOTE: As suggested earlier it is a good practice to exit the sketcher after each lug is completed to verify that the sketch is valid.

Figure 14.74 The Completed Vise Gasket Sketch

Figure 14 .75 The Completed Positive Geometry of the Vise Gasket Part

ADDING THE CENTER HOLE TO THE VISE GASKET

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Next the Hole command will be used to add the holes to each lug and for the center hole of the vise gasket. It is good practice to add negative geometry to a part once the positive geometry has been constructed. 40. Select the Hole command from the Sketch-Based Features toolbar (see Figure 14.76).

Figure 14.76 The Hole lcon 41. Pick the top horizontal surface of the vise gasket. 42. The Hole Definition dialog box appears (see Figure 14.77).

Figure 14.77 The Hole Definition Dialog Box 43. Select the Extension tab. 44. Set the depth field to Up To Last. 45. Set the Diameter to 3. 46. Set the Offset field to 0.

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47. The Direction of the hole should be toward the existing positive vise gasket and it should be set to Normal to surface. If the direction i s up then either pick on the arrow or select on the Reverse field. 48. Select the Positioning Sketch icon from the Hole Definition dialog box (see Figure 14.78). This command allows the holes to be constrained in the hole sketch.

Figure 14.78 The Positioning Sketch Icon 49. Select the Isometric View icon from the Quick View toolbar. 50. Zoom in on the sketch so that you can see the center point of the hole and the outside surface of the positive gasket. 51. Select the Constraint command. 52. Pick the center point of the circle. 53. Pick the the outside surface of the positive gasket. 54. An axis should appear (see Figure 14.79).

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Figure 14.79 Using a Coincidence Constraint to Locate the Hole 55. Depress the right mouse button and select the Coincidence option from the pop-up menu. 56. Exit the hole sketch. 57. Select OK from the Hole Definition dialog box. 58. The vise gasket should appear similar to Figure 14.80.

Figure 14.80 The Vise Gasket with the Center Hole

ADDING THE LUG HOLES TO THE VISE GASKET Use the same procedure that you used to add the center hole and add the three .375 diameter holes to each lug of the vise gasket. Use the coincidence command to make the center point of the hole coincidental to the axis of the partial cylinder of the lug. This will position the lug holes concentric to the partial cylinders of the lugs. The completed vise gasket is shown in Figure 14.81.

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Figure 14.81 The Completed Vise Gasket Part

NAMING THE FEATURES IN THE SPECIFICATION TREE Rename the features in the specification tree to match Figure 14.82.

Figure 14.82 The Completed Vise Gasket specification Tree

EXERCISE 14.6 In this exercise, you win use sketched standard and construction geometry with geometric and dimensional constraints to construct positive a prism, cylinder, cone, sphere, and torus. Each of these solid primitives will be separate features of a single part. Refer to Figure 14.83 for the approximate size and location of each 3D solid primitive

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Figure 14.83 The 3D Solid Primitives for exercise 14.6

SUMMARY There are several workbenches available in CATIA. Each of these has their own unique set of toolbars and commands. In this chapter, you worked with the sketcher and part workbenches. You learned to created 2D sketches. You were exposed to and applied geometric and dimensional constraints and cleaned up the sketch geometry using trim commands. Once the sketch was completed it was turned into a solid part.

15 CREATING 3D SOLID GEOMETRY

INTRODUCTION In the previous chapters you were introduced to the CATIA V5 interface and the different workbenches within it. Visualization of geometry was also introduced. Finally, you were introduced to the sketcher, shown how to construct sketched geometry, and constrain it through the use of both geometric and dimensional constraints. In this chapter you will learn how to create different types of solid geometry from sketched geometry.

OBJECTIVES After completing this chapter you will be able to: 1. Understand how sketched geometry is converted to 3D solid geometry. 2. Create pads from sketches. 3. Use different limit types to control the length of the pad. 4. Use the thick option to create negative areas in pads. 5. Create multi-pad extrusions. 6. Create pockets from sketches. 7. Understand and apply the hole command to create different types of holes on models.

CREATION OF 3D GEOMETRY

Chapter 15 Creating 3D Solid Geometry 2 All 3D solid geometry created in CATIA V5 is created from 2D sketches. The first solid feature created on a part is called the base feature. It is important to determine what geometric form the base feature should be, and orient it correctly when you initially begin to construct a part. Although the orientation of the feature can be changed later, it should not need to be changed if careful preplanning occurs. CATIA V5 has several geometric forms including Pads (positive extrusions), Pockets (negative extrusions), Shafts (positive revolutions), Grooves (negative revolutions), Holes, Ribs, Slots, Stiffeners, Lofts, and Removed Lofts (negative). In this chapter we will concentrate on Pads, Pockets, Shafts, Grooves, and Holes as well as other "dress up" features including fillets and chamfers.

CREATION OF A SIMPLE PAD When you create a Pad, CATIA is extruding a profile or a surface in one or two directions. You have to control the limits of creation and the direction of the extrusion. To create a Pad first you must select a sketch or an existing surface that will be used to construct it. As you become familiar with CATIA V5 you will see that there can be several sketches in one part, and these can be located on the specification tree. Notice in Figure 15.01 that there is only one sketch available as shown by the specification tree.

Figure 15.01 One Available Sketch When the Pad command (see Figure 15.02) is selected and the Pad Definition dialog box appears (see Figure 15.03). The Pad Definition dialog box is where

3 Applied Geometry for Engineering Design the geometric definition of the Pad is given. The following examples will illustrate how different types of Pads can be developed from a sketch.

Figure 15.02 Pad Icon

Figure 15.03 Pad Definition Dialog Box In every instance when you develop a Pad, a sketch must be selected before the Pad command is used or the sketch must be identified in the Pad Definition dialog box. In the Profile/Surface field of the Pad Definition dialog box, within the Selection field the selection option is No selection (see Figure 15.04). This means that a sketch must be determined. Sketch.1 was selected as the sketch for the creation of the pad and it now appears in the Selection field. Also notice that a preliminary pad appears in the geometry area and is based on the values given in the Pad Definition dialog box (see Figure 15.05).

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Figure 15.04 Profile/Surface Area of the Pad Definition Dialog Box

Figure 15.05 Preliminary Pad Based on Parameters from the Pad Definition Dialog Box Closer examination of Figure 15.05 reveals more information about the preliminary Pad specifications on the model itself. Notice a directional arrow points toward you. If you select the Reverse Direction or pick on the arrow itself, the arrow reverses direction and the Pad length flips to the opposite side of the sketch plane (see Figure 15.06). Thus, the sketch plane is by default at the

5 Applied Geometry for Engineering Design center of the Pad. Selecting the Mirrored extent command will place equal lengths on either side of the sketch plane (see Figure 15.07).

Figure 15.06 Reversing the Figure 15.07 Mirror Extent Extrusion Direction Option There may be times when unequal extrusion lengths must be given from either side of the sketch plane. Notice the First Limit area of the Pad Definition Dialog box. In this example, the First Limit is a dimension with a length of 2 and it is extruded in the direction of the directional arrow. There are several other First Limit Types but these are covered in subsequent paragraphs. The key point here is that you only have access to one limit of a given length, or two limits that are of equal length by using the Mirrored extent option. By pressing the More>> option, the Pad definition box reveals several more options (see Figure 15.08). In this example, the Second Limit length will be changed to 4, thus the length in front of the sketch plane is 2 and the area behind it has a length of 4. Notice that both of these values are a Dimension type and numerical values are given to define the length of the extrusion (see Figure 15.09).

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Figure 15.08 The More>> Option

Figure 15.09 Different Extrusion Lengths from the Sketch Plane

USING DIFFERENT LIMIT TYPES

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7 Applied Geometry for Engineering Design It is important to understand the different limit types to successfully use the Pad command. Examples of each of these will be given below through the use of a simple solid model and sketch. Notice in Figure 15.10 that the given solid has a sketch in black positioned at the bottom surface of the top prism. The default Limit type will always be the Dimension option. The second Limit type is Up to next and it is found directly below the Dimension limit once the field is expanded. If Up to next is chosen the extrusion will stop at the next surface in which completely contains the sketch profile. Notice in Figure 15.11 the extrusion did not stop at the second prism because the second protrusion boundary was smaller than the boundary of the sketch profile. This causes a manifold condition, which means it is mathematically impossible for CATIA to solve, thus the extrusion stops at the top surface of the third prism which completely contains the sketch profile.

Figure 15.10 Different Figure 15.11 Up to Figure 15.12 Up to Last Limit Types Solid and Next Limit Limit Sketch The third Limit option is the Up to last. The Up to last pad option will allow the extrusion of the sketch to go to the last plane before the last outermost curved surface of an object in this example. Notice that it went through all the prisms without problems because they did not define its stopping point (see Figure 15.12). The next Limit option is the Up to plane. The Up to plane option allows you to select the desired plane that you want your pad to extrude to. In Figure 15.13, the bottom plan e of the second prism was selected and the pad projected to this plane without error because you defined its stopping point. The final Limit option is the Up to surface option. The Up to surface option functions the same as the Up to plane option with one exception. Both the Up to plane and Up to surface Limit options allow planes to be chosen for ending the extrusion, but only the Up to surface option can be used to end an extrusion to a

Chapter 15 Creating 3D Solid Geometry 8 surface (see Figure 15.14). A surface is defined as any surface that is not planer but typically is curved.

Figure 15.13 Up to Plane Limit

Figure 15.14 Up to Surface Limit

If Up to plane, or Up to surface, or Up to Last limits is chosen or the desired plane has been selected you are given the Offset option that allows you to enter a desired distance from the selected plane or surface. The end of the extrusion will take the shape of the plane or surface from where it was defined. In Figure 15.15, the Up to surface offset was 1.5, which is measured from the limiting element of the bottom of the first feature, to the limiting element of the extruded pad feature. Notice that the end of the extruded feature has the same cylindrical shape as the base of the first feature. Figure 15.16 shows the same procedure except in this case, the Up to surface option was chosen and an offset value of three was used. Notice that the bottom of the extrusion is a planer surface because it is being offset from a planer surface. Offset also has several options that can increase the flexibility and power of the offset. These are accessed by right clicking on the offset field as shown in Figure 15.17. These will not be covered.

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Figure 15.15 Up to Figure 15.16 Up to Option with Plane Option with an Offset of 3

Figure 15.17 Offset Surface Options an Offset of 1.5

USING THE THICK OPTION The Thick option basically removes material from the inside of a model or adds material to the outside of a model and removes the existing material. The material removed will parallel the existing outside contour of the part; thus, it is extruded from the part's sketch. Once the Thick option is chosen, the Pad definition Dialog box expands to More>> and you can enter values in the Thin Pad area where two input fields can be used to enter data (see Figure 15.18). The Thickness1: area subtracts the distance you specify from the documents profile inside the model. In Figure 15.19, the Pad Definition dialog box is opened and the Thick option has been chosen. Now view the model before any material is removed from the object. In the Thickness 1 field 0.25 was entered and OK was selected thus all material inside that was a greater distance than 0.25 was removed from the object.

Figure 15.18 Thin Pad Input Fields

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Figure 15.19 Thickness1 of 0.25 with a Thickness2 of 0 The Thlckness2: option works just the opposite from the Thickness 1: option. Material is added outside of the profile at the desired thickness and the original solid material of the model is removed. In Figure 15.20, 0.25 was entered as the value for Thickness2:, and the resulting geometry placed solid material at a distance of 0.25 from the outside contour of the model.

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Applied Geometry for Engineering Design Figure 15.20 Thickness2 of 0.25 with a Thickness1 of 0

MULTI-PAD EXTRUSIONS When a single sketch contains many profiles, the inner profiles will become negative space (see Figure 15.21) if the Pad command is used. If you do not want these to be negative areas, the Multi-Pad (see Figure 15.22) option should be used instead of the Pad option. The Multi-Pad option allows multiple profiles to be extruded to independent lengths, but the multiple profiles cannot intersect and they must be closed. First, develop the sketch (see Figure 15.23) and then select the Multi-Pad option. The Multi-Pad Definition dialog box appears (See Figure 15.24). The domains are automatically generated by CATIA, and if you highlight a specific one you will see a sketch profile highlight. One of the Domains will be the base pad from which the other profiles are extruded. When you pick it in the domain field, the entire sketch will highlight (see Figure 15.25). If OK is selected, the Pad would appear with the negative spaces for each profile in it. In this example each domain was highlighted and a value was entered in the Length Field (see Figure 15.26).

Figure 15.21 Multiple Profiles Cause Negative Space in Pads

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Figure 15.22 Multi-Pad Icon

Figure 15.23 Sketch With Multiple Definition Dialog Box

Figure 15.24 Multi-Pad Profiles

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Applied Geometry for Engineering Design Figure 15.25 Base Pad Domain Field

Figure 15.26 Enter Length Values in the Domain Fields

CREATION OF A SIMPLE POCKET Creating a Pocket in CATIA is very similar to creating a Pad. Like the Pad, the Pocket is an extruded profile or sketch in one or two directions. Instead of adding material, material is removed. Because a Pocket removes material, a Pocket cannot be created unless there is existing solid geometry. You can control the limits of creation and the direction of the extrusion. To create a Pocket, select an existing sketch that is used to create the profile of the Pocket, and then select the surface where the Pocket will cut if the sketch is not positioned on the required surface. The Pocket command (see Figure 15.27) is selected and the Pocket Definition dialog box appears (see Figure 15.28). The Pocket Definition dialog box is where the geometric definition of the pocket is given. The following examples illustrate how different types of pockets are developed from a sketch.

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Figure 15.27 Pocket Figure 15.28 Pocket Definition Dialog Command Icon Box In this example, a rectangular sketch is placed on an existing model and it will be used to illustrate the Pocket command (see Figure 15.29). In Figure 15.30 the Pocket command was selected and Sketch.2 was selected as the profile sketch. Notice that CATIA generated the first Limit as a dimension of 3. Also notice that there are two directional arrows on a Pocket as opposed to one. The Reverse Direction arrow works exactly as the Reverse Direction did with a Pad. The cut will be changed from its current extrusion direction to the opposite direction (see Figure 15.31). Thus, the sketch plane for a Pocket is very similar to the Pad, and is by default at the center of the Pocket. The Mirrored extent command for a pocket functions exactly as a Pad and will equally place the length dimension on either side of the sketch plane.

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Applied Geometry for Engineering Design Figure 15.29 Rectangular Sketch Profile on the Model

Figure 15.30 Pocket Definition Dialog Box With the Model The Reverse Side arrow points toward the area of the model from which the material will be removed by the cut. This typically is pointing inside the profile (see Figure 15.31) of the sketch. In Figure 15.32 the Reverse side was changed to point outside of the sketch profile.

Figure 15.31 Reversing the Figure 15.32 The Model After Direction of the Pocket Extrusion Reverse Side Arrow was Changed

POCKET LIMITS AND LIMIT TYPES One or more limits can also be used with the Pocket command. If one limit is used the limit value will go in the same direction as the extrusion directional arrow. If the Mirror Extent is used the first limit distance will be extruded equally on both sides of the sketch plane. If two different limits are used the first

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limit will extrude in the same direction as the extrusion arrow and the second limit will extrude in the opposite direction of the extrusion arrow. Changing the Reverse Direction arrow, the limit values will change to the opposite side of the sketch plane. Like the pad command there are several limit types and these will be briefly discussed below. The Pocket Up to next limit works exactly as it does with a Pad. In Figure 15.33, the cut does not stop at the first prism it encounters because the sketch profile is not completely bounded by the prism. The cut continues passing through the top prism and when it encounters the second prism it cuts through the second prism's bottom surface. The second prism completely bounded the sketch profile allowing the cut to stop at it. The Pocket Up to Last limit removes material completely through the object. In Figure 15.34 the rectangular sketch cuts entirely through the model until the last surface is encountered. The next Limit option is the Up to plane. The Up to plane option allows you to select the desired plane that you want your Pocket to extrude. In Figure 15.35, the bottom plane of the third prism was selected, and the pocket was projected to this plane.

Figure 15.33 Up to Figure 15.34 Up to Last Limit Plane Limit

Figure 15.35 Up to Next Limit

The final Limit option is the Up to surface option. The Up to surface option functions the same as the Up to plane option with one exception. Both the Up to plane and Up to surface Limit options allow planes to be chosen to end each pocket, but only the Up to surface option can be used to end an extrusion to a surface (see Figure 15.36).

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The limit Pocket Offset option works the same way as it did with the Pad command. If either the Up to plane, Up to surface, or Up to Last limits are chosen, or the desired plane has been selected, you are given an Offset option that allows you to enter a desired distance from the selected plane or surface. The end of the extrusion will take the shape of the plane or surface from which it was defined. In Figure 15.37, the bottom of the third prism from the top was selected, and a 1.25 offset value was used to make the pocket cut into the bottom piece of geometry.

Figure 15.36 Up to Surface Limit

Figure 15.37 Pocket Offset Limit THE

POCKET THICK OPTION The Thick option used with a pocket gives some interesting results. In Figure 15.38 a single pocket is present on this model. In Figure 15.39, the Thick option was chosen and the Thickness1: was 0.25 and the Thickness2: was zero. The resulting geometry is a 0.25 negative area inside the profile of the pocket with the remaining area inside the 0.25 negative space, is positive geometry. Figure 15.40 illustrates the second example where the Thickness1: was zero and the Thickness2: was 0.25. The 0.25 negative space was placed outside of the sketch profile with the inside solid area being the same size as the original pocket. When there are enclosed identical profiles that are either larger or smaller, each alternate area will be positive and negative geometry. This caused the results as illustrated in figures 4.39 and 4.40.

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Figure 15.38 Model Figure 15.39 Thick Figure 15.40 Thick With a Single Pocket Option Using Option Using Thickness1 Thickness2

MULTI -POCKET EXTRUSIONS The Multi-Pocket Extrusions function is basically the same as multi-pad extrusions, except multi-pocket extrusions must have an existing pad (remember you cannot use any pocket commands unless solid geometry exists). In Figure 15.41, four areas of negative geometry exist that cut entirely through the pad. By using the multi-pocket option each of these areas can be turned into blind areas of different depths. First, choose the multi-pocket icon and then select the desired sketch. This sketch has to be a different sketch than the sketch used to develop the pad. You will give the required depths each pocket in the domain fields (see Figure 15.42). Be sure to double check that the extrusion direction is correct.

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Applied Geometry for Engineering Design Figure 15.41 Four Areas of Negative Geometry

Figure 15.42 The Completed Part

HOLES The Hole command (see Figure 15.43) allows for the development of several types of holes. The advantage of using a hole over using a circle in the sketch of an extrusion is that the hole type can be easily modified in the future.

Figure 15.43 Hole Icon

USING THE HOLE COMMAND Select the Hole command and then select the surface on which you want the hole to be placed. Notice that the top surface of the prism is highlighted, a potential hole is outlined, and the Hole Definition Dialog box appears (see Figure 15.44). There are three different tabs available in the Hole Definition dialog box to define the hole. The second tab is the Type tab and it defines the hole type. There are five different types of predefined holes available in CATIA: simple, tapered, counterbored, countersunk, and counterdrilled (see Figure 15.45). The simple, counterbored, and countersunk are the only holes that will be covered. The simple hole type will be the first one that will be discussed.

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Figure 15.44 Hole Definition Dialog Box

Figure 15.45 Predefined Holes in CATIA

SIMPLE HOLE A Simple Hole is a hole that has a constant diameter and a given depth if it is defined as a blind hole. Once the simple hole has been chosen you need to further define the hole with the Extension tab. Holes have the same limits and functions as pockets (see Figure 15.46). In this example, the Blind limit was chosen, thus the hole needs a diameter and depth defined for it. There are two

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input fields for defining a blind hole, the Diameter and Depth fields. The diameter of the hole was changed to 0.500 and the depth was changed to 0.750 (see Figure 15.47). Notice that you can use the Preview button to see how the hole diameter and depth changes. The direction of the hole can also be changed by selecting the Reverse button or picking on the highlighted arrow on the cylinder. Likewise the shape of the Bottom of the hole can be changed from a flat bottom hole to a V-bottom hole (see Figure 15.48).

Figure 15.46 Hole Limits

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Figure 15.47 Blind Hole Definition Figure 15.48 The Bottom Option POSITIONING A HOLE The hole needs to be dimensionally positioned. This is done by selecting the Positioning Sketch icon (see Figure 15.49). Selecting this icon puts CATIA into Sketcher mode with your view normal to the plane you chose to place the hole (see Figure 15.50). Now you dimensionally constrain the hole from the required sides of your model. The point on the sketch is the top of the axis of the cylindrical hole and you will dimension to this point. It is good modeling practice to dimension from planes and not edges. The model should be rotated to place both dimensions (see Figure 15.51). Exit the sketcher and pick the OK button. The hole is completely defined (see Figure 15.52).

Figure 15.49 Positioning Sketch Figure 15.50 Sketcher Mode Icon

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Figure 15.51 Dimensioning From Figure 15.52 The 0.500 Diameter Planes and not Edges x 0.75 Deep Simple Hole

CHANGING TIIE SIMPLE HOLE TO A COUNTERBORED HOLE Many times it will be necessary to change the type of hole required for a design. In the following example, the 0.500 diameter x 0.750 deep hole will be changed to a counterbored hole. First, you must select the hole from the specification tree. This brings up the Hole definition dialog box. The Type tab will be chosen and the Hole Type will be changed from Simple to Counterbored. You will enter the parameters that define the counterbored part of the hole in the Parameters field. The diameter field is the diameter of the counterbored hole (0.75) and the depth field defines the depth (0.25) of the counterbore (see Figure 15.53). Switch to the Extension tab and notice that all of the fields are identical to the simple hole. Thus you have to define the diameter of the pilot hole (0.25) and its limit (up to last). The hole will also have to be dimensionally constrained by a positioning sketch. If there are no other changes to be made, press OK and the counterbored hole is complete (see Figure 15.54).

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Figure 15.53 Parameter Fields

Figure 15.54 The Completed Counterbored Hole

CHANGING THE COUNTERBORED HOLE TO A COUNTERSUNK HOLE The procedure of changing an existing hole to a countersunk hole works the same way as changing the simple hole to the counterbored hold. Select the hole from the specification tree. Change to the type tab and choose the Countersunk Notice in Figure 15.55 that there are three different parameters available for defining the countersunk hole. For illustration purposes the Depth (0.25) & Angle (90) parameter was selected. Select the Extension tab and define the diameter of the pilot hole (0.25) and select OK (see Figure 15.56).

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Figure 15.55 Parameter Fields for Figure 15.56 The Completed the Countersunk Hole Countersunk Hole

REVOLVED FATURES Revolved features are geometric shapes that have been developed by rotating or revolving a sketch around a specified axis. In CATIA there are two different types of revolved features Shafts, which add positive geometry, and Grooves, which create negative space. The following paragraphs will explain the different ways that shafts and grooves are created.

SHAFTS To create a Shaft (see Figure 15.57), you first need to sketch a partial profile. In Figure 15.58 the Shaft option was picked and the Shaft Definition dialog box appeared. Notice many of the fields in the Shaft Definition dialog box are very similar to the pad and pocket dialog boxes. First, the Limits of the shaft need to be defined. The default limits are the First angle of 360° and the Second angle of 0°. This makes full revolution shaft (see Figure 15.59). In Figure 15.60 the First angle was 80° and the Second angle was 0°. The default revolution angle is clockwise, but selecting the Reverse Direction button or directional arrow on the geometry can reverse it.

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Figure 15.57 The Shaft Icon

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Figure 15.58 Shaft Definition Dialog Box

Figure 15.59 360° Revolved Shaft Figure 15.60 80° Revolved Shaft To define the shaft, you must select a sketch profile from the specification tree and an axis of revolution (see Figure 15.61). In this example the inside vertical line of the sketched feature was chosen as the axis of revolution (see Figure 15.62). The resulting shaft will appear the same as the shaft in Figure 15.59. The axis does

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not have to be on the sketch profile it can be selected from any edge of an existing solid.

Figure 15.61 Axis Selection Dialog Box

Figure 15.62 Selecting the Sketch Profile and the Axis of Revolution

GROOVES The Groove command functions almost identically as the Shaft command. You need to have a sketch defined that will be revolved around the existing solid model as set by the limits (see Figure 15.63). Next, an axis of revolution must be defined for the sketched geometry to be revolved around (See Figure 15.64). In this example, the axis of the solid part was chosen as the axis of revolution for the groove feature. Figure 15.65 is the resulting model after the Groove cut is complete.

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Figure 15.63 Sketch for the Groove

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Applied Geometry for Engineering Design Figure 15.64 Axis for the Groove

Figure 15.65 Completed Groove

DRESS UP FEATURES CATIA calls fillets, rounds, champers, shells, draft angles, thickness, and threads Dress Up Features. The Edge Fillet and the Chamfer will be covered in this text. Fillets and rounds are used to round off sharp corners of castings. Exterior rounds are called fillets, and interior rounds are called rounds. Fillets and rounds are important because they relieve stress points in castings, allow castings to be removed from molds, and are safer because there are no sharp corners. EDGE FILLET The Edge Fillet (see Figure 15.66) allows a constant round radius to be removed from the edge of a surface or between the intersection of two the surfaces. Figure 15.67 shows the Edge Fillet Definition dialog box. The first field is the Radius field. This is where the required radius for the fillet or round is entered. The Object(s) to fillet: field is where you pick the edges that you want the fillets to be applied. In this example, the top of the base cylinder, the line of intersection between the cylinders, and the top of the upper cylinder were chosen. Figure 15.68 shows the results of fillets being applied to the model. More advanced options can be applied to the Edge Fillet but will not be covered because of their complexity.

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Figure 15.66 Edge Fillet Icon

Figure 15.67 Edge Fillet Definition Dialog Box

Figure 15.68 Fillets Applied to the Model

CHAMFER The Chamfer command (see Figure 15.69) is used to eliminate sharp comers by removing material and making a beveled edge. Once the chamfer command is selected, the Chamfer Definition dialog box appears (see Figure 15.70). First, the edges to be chamfered are selected and are displayed in the Objects(s) to chamfer field. In the Mode field, the type of Chamfer is selected. There are two options the Length/Angle option specifies that you give a length (0.25) by a degree angle (45). The length is defined as the distance from a selected edge and the angle from the end of the given length back towards the object being chamfered (see Figure 15.71). The Length1/Length2 mode allows you to specify the length away from the selected edge, and the length down from the selected edge (see Figure 15.72). The resulting chamfer from the Length1/Length2 option is shown in Figure 15.73.

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Figure 15.69 Chamfer lcon

Figure 15.70 Chamfer Definition Dialog Box

Figure 15.71 Length/Angle Chamfer Definition

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Figure 15.72 Length/Length Chamfer Definition

Figure 15.73 The Completed Chamfer

EXERCISE 15.1 -VISE JAW In this exercise the startpart will be modified to include 3D construction geometry (reference elements). 3D construction points, lines, and planes are referred to as reference elements in CATIA (see Figure 15.74). Reference elements are geometric construction elements that are very similar to 2D construction elements used in sketches with the further advantage of being to be located and orientated in 3D space. They can be used by multiple features for both 2D sketches and as 3D reference entities such as skeleton models used in assemblies. They will be introduced throughout different chapters as they are used in the development of different sketches, parts, and products. In this specific example three reference planes will be added to the startpart. These reference planes will be parallel to the xy plane (horizontal), yz plane (frontal), and the zx plane (profile). Thus if a part needs to be repositioned from front to back or front to back then the reference frontal plane can be moved either forward or backward. Likewise the horizontal reference plane allows geometry to be repositioned up and down and the profile reference plane allows geometry to be positioned left or right. Also in this exercise more examples of dimensional constraints will be presented. The use of the hole command will be required along with the rounds and chamfers commands. Some specific steps will be left out because they have been covered in previous tutorials.

CREATING STARTPART REFERENCE PLANES 1. Open your CATIA startpart file.

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2. Position the cursor over one of the toolbars and click with the right mouse button or select Toolbars from the View pull-down menu. 3. Select Reference Elements Extended and the Reference Elements toolbar will be docked. 4. Drag it onto the 3D work space (see Figure 15.74). HINT: While dragging a toolbar depress the Shift key to change its orientation from vertical to horizontal or from horizontal to vertical. 5. Select the Plane option from the Reference Elements toolbar and the Plane Definition dialog box will appear (see Figure 15.75).

Figure 15.74 The Reference Figure 15.75 The Plane Definition Elements Toolbar Dialog Box 6. Notice that the Plane type field is set to Offset from plane. By default CATIA will automatically set the Plane type to Offset from plane or this field will be set to the reference plane option that was last used. The various other reference plane options will be covered later. 7. Also note that the Reference field is highlighted. It will be automatically highlighted and is prompting you to select a plane as the parent plane used in the creation of the new reference plane. This new reference plane will be offset a set distance and parallel to the parent plane. The parent plane can be a default reference plane, another reference plane, or a plane from an existing part.

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8. Select the yz (frontal plane) from the Specification Tree. In the Plane Definition dialog box enter 1.0 into the Offset field. NOTE: the Reverse Direction button allows you to place the reference plane in front (positive X) or behind (negative Z) the YZ plane (frontal). This same procedure can be used to locate a reference plane to the right or left of the ZX plane (frontal) or above or below the XY plane (horizontal). 9. Accept OK and a reference plane with a vertical orientation that is parallel with the default YZ plane (frontal) has been created. 10. Repeat this procedure to create a reference plane that is parallel to the XY plane (horizontal) and the third new reference plane parallel to the ZX plane (profile). 11. Rename the three newly created reference planes in the Specification tree as shown in Figure 15.76.

Figure 15.76 The Three New Repositioning Reference Planes The first newly created reference plane appears in the Specification tree under the Geometrical Set.1 branch and has a default name of Plane.1. As successive reference planes are created they will likewise be named Plane.2, Plane.3, etc. in their order of creation. Even if an existing plane is deleted, newly created reference planes will be named in chronological order based on all previously created reference planes, including any deleted reference planes. This CATIA naming convention is the CATIA default naming convention that is standard for all standard and reference geometries, parts, assemblies, patterns, and transformed features.

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There are opposing theories/standards used in industry in regards to the use of using either the default CATIA mutually perpendicular reference planes or three created mutually perpendicular reference planes to spatially locate the base positive feature of a part. If the default reference planes are used then it will be more difficult to move the parts base feature at a later time. If created reference plane are used then the sketch of the base feature can be spatially relocated in 3D space. There are advantages and disadvantages with the use of either method, thus verify what standard is being used by the company that you are working for. Likewise there are two theories on the practice of renaming the features in the specification tree. Throughout this book you will be required to rename the specification tree features but man companies require the adventurous use of the default feature names for programming and CAD automation purposes. The practice of renaming the default features lies in the fact that the model can be used at a later time by you or another user and the features of the specification tree give a "verbal history" of how the part was constructed. CREATING THE

BASE FEATURE OF THE VISE JAW 12. Select the YZ(frontal) positioning plane as the sketch plane for this part. 13. Use the profile tool to make a rough sketch of the outline of the part (see Figure 15.77). 14. Add the geometric constraints to the sketch (see Figure 15.78).

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Figure 15.77 Unconstrained Figure 15.78 Geometrically Sketch of the Base Feature Constrained Sketch of the Base Feature All required geometric constraints should be added to the sketch before dimensional constraints are added so that the general geometric relationships (constraints) are maintained even if the geometric sizes (dimensional constraints) are increased or decreased. The order that the geometric constraints are added is also important. Typically it is best to add all vertical and horizontal constraints before adding tangency constraints. Experiment with different orders of applying geometric constraints on the sketches and apply these experiences to the creation of new parts. 15. Add the Dimensional Constraints to the sketch (see Figure 15.79). If all of the geometric and dimensional constraints are correctly added to the sketch the sketch will turn green signifying that it is fully constrained.

Figure 15.79 Geometrically Constrained Sketch of the Base Feature 16. Exit the sketcher. 17. Select Pad from the Sketch-Based Features toolbar.

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18. The Pad Definition dialog box will appear. Select the More>>> button. Notice that there are now two Limit directions. 19. Set the length of the First Limit to 1.5. 20. Use a formula to set the second limit equal to the first limit of 1.5 (see Figure 15.80). 21. Select OK and the Pad will be completed (see Figure 15.81). By using two limits to control the Pad and making the second length equal to the first the length of the pad is centered on its sketch plane. If one limit is used the the Pad will be a one directional Pad. If a two limit Pad is used and the length or the first limit is different from the length of the second limit then the Pad will not be centered on its sketch plane.

Figure 15.80 Pad Settings for the Base Feature Feature

Figure 15.81 Completed Base

MASS PROPERITIES AND THE SHELLCOMMAND CATIA part models are true solid models. Like real objects these models can have various types of properities. CATIA has preset property standards that can be modified as required. You will add iron as the material for this part and then determine the mass of the part. The Shell command will then be used to remove material from the part. 22. Select Part1 in the Specification tree to highlight it. 23. While Part1 is highlighted click the right mouse button and from the Popup menu select Properities. The Properities dialog box will appear.

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24. Select the Mass tab. 25. Select OK to exit the Properities dialog box. Notice that there are general properities such as mass, volume, density, and surface along with the center of gravity and inertia. Also note that only the volume, surface, and center of gravity have any values other than zero. This occurs because by default CATIA does not have a default material applied to it. The next steps will show you how to apply a specific material to the part. 26. Locate and select the Apply Material toolbar and icon (see Figure 15.82). The Library dialog box will appear (see Figure 15.83). Notice that there are several different material properities available. 27. In the Specification Tree select Part1 and it will highlight in orange. 28. In the Library dialog box select the Metal menu and the Iron figure. 29. Select OK to apply Iron as the parts material. 30. Determine the Mass of Part1 and it should be approximately 3.257kg. Notice that a Parameters branch has been added to the Specification Tree and that Iron has been added to the Geometrical Set. If you would want to change the material then you would have to delete Iron from the Geometrical Set and apply a new material.

Figure 15.82 Apply Figure 15.83 The Library Dialog Box Materials Toolbar & lcon

USING THE SHELL COMMAND TO REDUCE THE MASS

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The Shell command will now be used to remove internal material from Part.1. The Shell command is used to remove faces (planes & surfaces) from parts and give a thickness to the remaining faces. This procedure allows internal materials to be removed reducing the mass of the part and thus making it lighter. 31. Select the Shell icon from the Dress-Up Features toolbar (see Figure 15.84).

Figure 15.84 The Shell Command 32. The Shell Definition dialog box will appear. 33. In the Shell Definition dialog box change the Default inside thickness to .25. 34. Highlight the Faces to remove field and select the right profile and bottom horizontal planes and the right cylindrical surface. They will be highlighted in orange (see Figure 15.85).

Figure 15.85 Creating the Shell 35. Select OK from the Shell Definition dialog box and the shell feature is created (see Figure 15.86) 36. Determine the Mass of Part1 and it should be approximately 1.072kg. Many times the shell command is used to reduce the amount of material or mass of a part to make it lighter in weight. Weight reduction is a critical design requirement for airplanes and automobiles.

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Figure 15.86 The Completed Shell Feature

USING EXISTING GEOMETRY TO CREATE NEW FEATURES Many times existing 3D geometry can be used in the development of sketches to create new features. In CATIA sketches 2D geometric elements can be projected from planer and surface edges and from the intersection for 3D geometric entities. The example below will be used to create the vise jaw feature from the 3D geometry of the base feature. 37. Create two new reference planes from the existing YZ (frontal) positioning plane. The first one will be located 3" generally in front of the base feature and be named front jaw plane and the second one will be located generally behind 3" behind the base feature and it will be named back jaw plane. Use a formula to control the dimension for the location of the back jaw plane and the parent dimension is the 3" location dimension of the front plane. HINT: use the specification tree to select the required parent dimension of the formula for the location of the back jaw plane. 38. Start the Vise Jaw feature by selecting the YZ (frontal) positioning plane as the sketch plane. 39. From the Operation toolbar select the Project 3D Elements icon (See Figure 15.87).

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Applied Geometry for Engineering Design Figure 15.87 The Project 3D Elements Icon

40. From the Normal View Select every 3D edge line and curve from the existing 3D Base feature except the bottom horizontal and the lower right vertical lines. The projected 2D sketch entities will be highlighted in yellow. 41. Select the line command and construct a horizontal standard line starting at the bottom point of the right hand arc and extend it to the projected left side vertical line. Geometrically constrain this line to a horizontal orientation. 42. Use the trim command to trim the left projected vertical line to the standard horizontal line. 43. Change to an isometric viewpoint to better visualize the sketch geometry (see Figure 15.88). A two limit Pad will now be created from this sketch. The projected geometry coupled with the standard horizontal line will create the profile shape of the Pad feature. The front jaw plane will control the First Limit (front to back distance) from the YZ (frontal) positioning plane and the back jaw plane will control the Second Limit likewise from the YZ (frontal) positioning plane. Because the distance is equal between the front and back jaw positioning planes as controlled by the formula that located the back positioning plane the Pad will be centered on the base feature. If the sizes of the base feature geometry change the sketch of this Pad will change because it is a child of the base feature. 44. Select the new sketch and the Pad command. 45. Select the More>> button to access the Second Limit fields. 46. In Type field of the First Limit select Up to plane and select the front jaw plane. 47. Repeat this procedure for the Second Limit except choose the back jaw plane (see Figure 15.89). 48. Select the OK button to complete the Pad (see Figure 15.90). 49. Rename the Pad to Vise Jaw Pad.2 in the Specification tree.

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Figure 15.88 The Sketch Vise Jaw

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Figure 15.89 Using Up to Plane Limits for the

Figure 15.90 The Vise Jaw Feature

ADDING SUPPORT USING EDGE FILLETS Fillets (interior) and rounds (exterior) are used to improve the design of cast metal or injected plastic parts by eliminating sharp edges. The removal of sharp edges allows these parts to be removed from molds, reduces the probability of stress because of uneven cooling, add support, and remove sharp edges.

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In CATIA the command to add fillets and rounds is called the Edge Fillet command and it is located on the Dress-up Features toolbar (see Figure 15.91). The following steps will demonstrate the use of the Edge Fillet Command. 50. Select the Edge Fillet command from the Dress-up Features toolbar and the Edge Fillet Definition dialog box appears (see Figure 15.92).

Figure 15.91 The Edge

Figure 15.92 The Edge Fillet Definition Fillet lcon dialog Box 51. In the radius field set the radius to 1". 52. Select the intersection between the horizontal and vertical plane of the object labeled EDGE FILLET. 53. Change your orientation and depress the Ctrl key and select the corresponding edge of intersection formed by the aforementioned planes on the back side of the part. The selection group formed will be shown in the Object(s) to fillet: field of the Edge Definition Dialog box as illustrated in Figure 15.93.

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Figure 15.93 The Selected Edges for the Edge Fillet 54. Select OK to exit the Edge Definition Dialog box. 55. The resultant 3D geometry is added to the part (see Figure 15.94). 56. Select the top horizontal plane as a new sketching plane (see Figure 15.94).

Figure 15.94 The Completed Support Edge Fillet Feature 57. Create the sketch illustrated in Figure 15.95. Use construction and standard element lines and circles or arcs, construction Project 3D elements, trimming operations, and geometric constraints in its construction.

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Figure 15.95 The Completed Sketch for the Edge Fillet Pocket Feature 58. Exit the Sketcher. 59. Create a Pocket feature from the feature with the First Limit Type: as Up to last. 60. The resultant geometry should appear the same as Figure 15.96.

Figure 15.96 The Completed Edge Fillet Pocket Feature

ADDING THE SUPPORT BOSS A boss is added to a part to strengthen the part or to allow it to have more functionally. The next few steps will describe how to add the boss support to the part. 61. Select the left end vertical surface as a new sketch surface (see Figure 15.96). 62. Create the sketch illustrated in Figure 15.97. Use construction and standard element lines and circles or arcs, construction Project 3D elements, trimming operations, and geometric constraints in its construction.

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63. Exit the sketch and create a Pad named Boss Support Pad from this sketch with a length of .375 (see Figure 15.98).

Figure 15.97 The Completed Sketch for the Boss Support Pad

Figure 15.98 The Completed Boss Support Pad Feature

64. Use the Hole command to create a through hole on the left end vertical plane of the part. The diameter of the hole is 1" and the center point of the sketch point is coincidental to the axis of the Support Boss Pad feature. 65. Name this feature the Adjustment Shaft Hole. 66. Use the Hole command to create a blind hole with a depth of .5" on the upper right side profile plane of the part. The diameter of the hole is .25" and uses the dimensions given in Figure 15.99 to locate the center point of the sketch. NOTE: A formula was used to center the hole vertically. 67. Select the Thread Definition tab of the Hole Definition dialog box. 68. Select the Threaded button and the Thread Definition fields will become active and a standard thread will be defined based on the nominal size of the blind hole (.25) as shown in Figure 15.100.

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Figure 15.99 The Hole Sketch Figure 15.100 The Thread Dimensional Constraints Definition Tab and Settings 69. Create the Back Jaw Hole of the vise jaw part again using the Hole option. Refer to the sketch dimensional constraints of the sketch for its placement (see Figure 15.101) The size constraints and threads will be identical to the Front Jaw Hole. 70. Label it as Back Jaw Hole in the specification tree. 71. The completed part is called the Vise Jaw (see Figure 15.102).

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Figure 15.101 The Complete Figure 15.102 The Completed Sketch for the Back Jaw Role Vise Jaw Part 72. In the specification Tree rename the PartBody to Vise Jaw PartBody. 73. The features of the Specification Tree should be named the same as the features in Figure 15.103.

Figure 15.103 The Completed Vise Jaw specification Tree

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EXERCISE 15.2 - SPOKED RIM In this exercise you will use the Shaft command to create revolved geometry. Similar to the pad and pocket commands the shaft command requires a 2D sketch and an axis of revolution to create the resultant revolved 3D geometry. The axis can be a standard or construction geometry line in the sketch, a edge of an existing 3D geometry in a part or an assembly, or a reference line element. 1. Select the ZX (profile) positioning plane as the sketch plane. 2. Use the profile tool to create the profile and the axis line as illustrated in Figure 15.104. 3. Add the geometric constraints to the sketch (see Figure 15.105).

Figure 15.104 The Un-constrained Profile

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Figure 15.105 The Dimensionally Constrained Profile 4. Add the dimensional constraints (see Figure 15.106).

Figure 15.106 The Dimensionally & Geometrically Constrained Profile 5. Exit the sketcher. 6. From the Sketch-Based Features select the Shaft command (see Figure 15.107).

Figure 15.107 The Shaft Command lcon 7. The Shaft Definition dialog box will appear. 8. Select the Thick Profile button and the Shaft Definition dialog box will expand.

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9. In the Thickness1: field change the value to .25 (see Figure 15.108).

Figure 15.108 The Shaft Definition Dialog Box 10. Highlight the Axis Selection field and select the horizontal sketch axis in the sketch (see Figure 15.108). 11. Select the OK button and the rim will be created as shown in Figure 15.109. 12. Save this file using the required file name.

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16 PATTERNS AND 3D TRANSFORMATIONS

INTRODUCTION The ability to replicate geometry is a central function of any CAD program. CATIA has the ability to duplicate solid features in three different ways. Rectangular patterns allow you to create copied features in a linear array. Circular patterns allow you to duplicate features using an axis to create a radial array. User-defined patterns allow you to create a customized pattern. CATIA's 3D transformations allow you to modify the orientation of existing geometry by translating, rotating, symmetry translating, and mirroring. This chapter will give you more detail on how you can use these commands to create documents. OBJECTIVES After completing this chapter you will be able to: 1. Use rectangular patterns to create linear arrays. 2. Use circular patterns to create radial arrays. 3. Use user-defined patterns to create unique patterns. 4. Use translations to move 3D geometry. 5. Use rotations to move 3D geometry. 6. Use symmetry to move 3D geometry about a specified plane. 7. Use mirroring to move and copy 3D geometry about a specified plane.

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RECTANGULAR PATTERNS Rectangular Patterns are used to duplicate geometry with a linear array. A rectangular pattern can be in one or two directions. A rectangular pattern in one direction will duplicate geometry in rows, and a two directional pattern will duplicate geometry in both rows and columns. The rectangular pattern command (see Figure 16.01) is located on the Patterns Toolbar, which is found on the Transformation Features Toolbar (see Figure 16.02).

Figure 16.01 The Rectangular Pattern lcon When you select the Rectangular Pattern Icon, the Rectangular Pattern Definition dialog box is displayed (see Figure 16.03). Notice that there are two tabs (First Direction & Second Direction) that define if the pattern will be either rows or rows and columns.

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Figure 16.02 The Patterns and Figure 16.03 The Rectangular Pattern Transformations Toolbars Definition Dialog Box ONE DIRECTIONAL

RECTANGULAR PATTERN There are three choices for Parameters that define a rectangular pattern (see Figure 16.04). In Figure 16.05, there is a given solid with three cylindrical pads on the top surface. We will use each cylindrical pad to demonstrate each pattern type. The first one is lnstance(s) & Length. With this choice, you give the total number of copies (instances) and the total length from the first to the last instance. In this example, there are two instances with a length of two. But before the pattern can be created, the object to pattern must be chosen, and the reference element must be defined. To define the Object to Pattern, click on its field until it highlights (see Figure 16.06). In this example, the first cylindrical pad closest to the front of the object was selected. Notice that Pad2 is highlighted (see Figure 16.07). Next, the Reference Direction must be defined (see Figure 16.08). The reference direction defines the direction that the pattern will follow. Highlight the reference element field and select a reference element. In this example, the front top edge of the prismatic pad was selected (see Figure 16.09). Notice that the reference element is Edge.1 and the edge is highlighted. Also note that the cylindrical pad was duplicated but not in the correct direction. This occurred because the duplicated pad is not on the prismatic pad. The reverse button was used to change the direction of the pattern and OK was selected. Figure 16.10 shows the completed pattern with two instances, and the second instance being two inches away from the first pattern. No matter which type of pattern parameter is chosen, the object to pattern and the reference direction must be defined. Additionally, the pattern direction may have to be reversed to correctly locate the duplicated geometry.

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Figure 16.04 Instances and Figure 16.05 Given Solid With Spacing Parameter Three Cylindrical Pads

Figure 16.06 Object to Pattern Field

Figure 16.07 Pad.2 in the Object to Pattern Field

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Figure 16.08 Defining the Reference Dimension

Figure 16.09 Selecting the Front Top Edge of the Prismatic Pad

Figure 16.10 The Reverse Button issued to Change the Direction of the Pattern The second rectangular pattern parameter is Instance(s) & Spacing. With this parameter, the user gives the total number of required instances with the distance between each instance being the spacing. In this example, four instances were chosen with a one-inch space between each instance. The second cylindrical pad (Pad.4) was chosen as the object to copy; the same reference

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element was selected as in the previous example. The direction was also reversed (see Figure 16.11). The completed rectangular pattern contains four instances with a one-inch space between each instance (see Figure 16.12).

Figure 16.11 Reversing the Direction of the Pattern

Figure 16.12 The Completed Pattern The third rectangular pattern parameter is Spacing & Length. With this option, the total length of the pattern and the required spacing, controls the number of instances. For this example, the back cylindrical pad (Pad.3) will be patterned using the same front edge of the object as the reference element. The Spacing is .5 inches with an overall length of 3 (see Figure 16.13). The resulting pattern

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will have seven instances located .5 inches apart across the length of three (see Figure 16.14).

Figure 16.13 Spacing is .5 Inches With an Overall Length of 3

Figure 16.14 Seven Instances Located .5 Inches Apart Across the Length of Three

The More>> tab expands the Rectangular Pattern Definition dialog box and gives you more options to modify the pattern. For the context of this book, these options will not be covered.

TWO DIRECTIONAL RECTANGULAR PATTERNS Two Directional Rectangular Patterns function and are defined the same way as one directional patterns. The object to be patterned will be selected in the first direction, and it will become the default object for the second direction. For the second direction, the parameters will need to be selected and can be different from the first direction. The reference direction will also have to be defined and this must to be different then the reference direction for the first direction. The following example will show you how to create a two directional rectangular pattern.

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In the First Direction, the parameter chosen is the Instance(s) & Spacing with 3 instances and a spacing of 1.5 inches. The selected Pad is the positive cylinder, and the reference element is the front top edge of the prism (see Figure 16.15).

Figure 16.15 The First Direction Parameter is Instance(s) & Spacing In the Second Direction, the parameter chosen was the Instance(s) & Length option. Four instances were chosen with a length of three inches. The reference element was defined as the right, top edge of the prismatic pad (see Figure 16.16). Note the two directional arrows are labeled one and two for each direction of the pattern. Figure 16.17 shows the completed pattern.

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Figure 16.16 Reference Element was Defined as the Right, Top, Edge of the Prismatic Pad

Figure 16.17 The Completed Pattern

CIRCULAR PATTERNS Circular Patterns are used to duplicate geometry with a radial array. The circular pattern command, (see Figure 16.18) like the rectangular pattern, is

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located on the Patterns Toolbar, which is found on the Transformation Features Toolbar.

Figure 16.18 The Circular Pattern lcon When you select the Circular Pattern Icon the Circular Pattern Definition dialog box is displayed (see Figure 16.19). Notice that there are two tabs (Axial Reference and Crown Definition) that can be used to define the pattern. Only the Axial Reference circular pattern will be covered.

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Figure 16.19 The Circular Pattern Definition Dialog Box

AXIAL REFERENCE PATTERNS There are four choices for Parameters used to define the circular pattern (see Figure 16.20). Three of these will be covered and the fourth, the Complete Crown, will not be covered because it is beyond the scope of this material. In Figure 16.21 there is a given part with one spoke that will be patterned using the circular pattern. The first parameter is Instance(s) & total angle. With this choice, you give the total number of copies (instances) and the total angle between each instance. Before the pattern can be created, the object to pattern must be chosen, and the reference element must be defined. To define the Object to Pattern, click on its field until it highlights (see Figure 16.22). In this example the single horizontal spoke was selected. Notice that it highlights and is Pad1 in the Object to Pattern field (see Figure 16.23).

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Figure 16.20 Parameters Used to Figure 16.21 Given Part With to Be Define the Circular Pattern Patterned with a Circular Pattern

Figure 16.22 Defining the Object to Pattern

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Figure 16.23 The Horizontal Spoke is the Feature to Pattern Next, the Reference Direction must be defined (see Figure 16.24). The reference direction defines the axis that the pattern will duplicate instances around. Highlight the reference element field and select a reference element. In this example, the vertically orientated positive cylinder located at the center of the part was selected (see Figure 16.25). Notice that the reference element is Face.2, and the patterned cylinders are displayed in a preview. The reverse button can be used to change the location of the spoke. Figure 16.26 shows the completed pattern with two instances and the second instance being 45° away from the first pattern. If you want to use the Instance(s) & total angle option to create three spokes equally spaced around the hub you will need to enter four instances (see Figure 16.27). Whenever you need equally spaced instances, you will always enter one more than the required number with the Instance(s) & total angle option. Remember, no matter which type of pattern parameter is chosen, the object to pattern and the reference direction must be defined. Additionally, the pattern direction may have to be reversed to have the pattern correctly located.

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Figure 16.24 Defining the Reference Direction

Figure 16.25 The Vertical Positive Cylinder is the Reference Element

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Figure 16.26 The Horizontal Spoke is the Feature to Pattern

Figure 16.27 Four is Entered in the Instance Field The second circular pattern parameter is the Instance(s) & Spacing. This option works very much like the Instance(s) and total angle except that you are giving the angle between each instance. The object to pattern and the reference angle must be selected. Figure 16.28 has two instances and an angle of 90° between each instance. In Figure 16.29 four instances were used with the angular spacing set to 90° thus four spokes were duplicated at equal angles around the hub.

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Figure 16.28 Two Instances and a Angle of 90° The third circular parameter is the Angular Spacing & Total Angle. With this option, you give the required angle and the total angle. In Figure 16.30, the required angular spacing is 90° with a total angle of 180°. In Figure 16.31 the angular spacing is 45° with a total angle of 360° thus eight spokes were duplicated and equally spaced.

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Figure 16.29 Four Instances and a Angle of 90°

Figure 16.30 Angular Spacing is 90° with a Total Angle of 180°

Figure 16.31 Angular Spacing is 45° with a Total Angle of 360° There are several additional options for circular patterns available under the More>> but these options are out of the scope of this book.

USING REFERENCE ELEMENTS WITH CIRCULAR PATTERNS

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In the examples above, a cylinder was chosen as the reference element for a circular pattern to be rotated around. In many cases you will not have a cylinder to use as a reference element. You have to use a reference point or line as the reference element. The following two examples will illustrate using both a reference element point and a reference element line to create a circular pattern. Reference elements will be covered in detail later. In the first example, a circular pattern will be used to make a radial pattern of the given hole using a reference point. In order to do this type of pattern on a prism that does not contain a cylinder, a reference point can be used as the reference element. In this example a reference point is located in the middle of the prism (see Figure 16.32). The circular pattern command was chosen and the circular definition dialog box appears. The hole was chosen as the object to pattern. When you use a reference element point, you first must select the surface on which the point reference element lies. Then, you must highlight the reference element field and select the reference element point (see Figure 16.33). Figure 16.34 is the completed pattern.

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Figure 16.32 Reference Point Located at the Center of the Prism

Figure 16.33 Selecting the Reference Element Point

Figure 16.34 The Completed Circular Pattern In this example the circular pattern's reference element will be a reference element line (see Figure 16.35). In the reference element field, select the reference line as the reference element and the hole as the object to pattern (see Figure 16.36). Figure 16.37 is the completed pattern.

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Figure 1 .3 Using a Reference Line as the Circular Pattern’s Reference Element

Figure 16.36 Selecting the Reference Element Line

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Figure 16.37 The Completed Circular Pattern

USER PATTERN User Patterns are used when you want to duplicate features that cannot be done with either a rectangular or circular pattern. The User Pattern command (see Figure 3.38) lets you duplicate a feature in as many locations that are required. Each instance must be located by specifying anchor points in a sketch. Typically the anchor points will be 2D points.

Figure 16.38 The User Pattern Figure 16.39 Four Required Element Concentric Holes In Figure 16.39, four holes that are concentric to the four arcs are required. The first step is to create a sketch on which four 2D points will be located. The four 2D points are located concentric to the existing top two and bottom two arcs. In this case, you will make the points concentric to the arcs by using the coincidence geometric constraint (see Figure 16.40). After all the points are constrained, exit the sketcher. Next, you will add one hole that is concentric to one of the 2D points with the hole command. It does not matter which point the hole is concentric with (see Figure 3.41). Select the User Pattern command and the User Pattern Definition dialog box appears (see Figure 16.42). Notice that like the rectangular and circular patterns, you have to specify the instances for the pattern and the object to be patterned. In this example, the object to pattern is the hole, thus the Object field was selected, and the hole was chosen. Next, the Positions field was selected, and one of the sketch points was selected. It does not matter which sketch point is selected to use as a reference to create the pattern (see Figure 16.43). The completed pattern is shown in Figure 16.44.

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Figure 16.40 Making the Points Concentric To the Existing Arcs

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Figure 16.41 Locating a Hole Concentric to a Sketch Point

Applied Geometry for Engineering Design

Figure 16.42 User Pattern Dialog Box

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Figure 16.43 Selecting a Sketch Point

Figure 16.44 The Completed User Pattern

EXPLODING PATTERNS Many times you will be required to alter one or more instances of a pattern without changing the entire pattern. The Explode command is used to perform this task because deleting the pattern will eliminate all instances of the pattern except the original feature. The explode command creates individual instances of every feature that was in the pattern and allows each instance to be independently modified without changing any of the other instances. The explode command is turned on by highlighting the pattern to be exploded in the specification tree with the right mouse button. At the bottom of the pop up menu, move your mouse over the pattern object and select explode in the second pop up window (see Figure 16.45). This explodes the pattern into individual features (see Figure 16.46).

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Figure 16.45 Selecting Explode in Figure 16.46 The Pattern Exploded the Second Pop Up Window Into individual Features Patterns are important for creating duplicate instances of geometry because of time savings and the required design intent. The next section will cover transformations, which let you translate, rotate, and mirror 3D geometry.

TRANSFORMATIONS Transformations Features are used to manipulate 3D documents by changing their orientation or the position and are located on the Transformation features toolbar (see Figure 16.47). Although using different transformation commands can change the orientation of a document, it is good modeling practice to try to build the design intent into the document initially. This is done so that the

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orientation corrections do not have to be made to the document later. The different transformation features will be discussed in the following paragraphs.

Figure 16.47 Transformation Features lcon

TRANSLATION The Translation command (see Figure 16.48) is used to change the position of a document along a straight path. When you select the Translation Icon, a question pop-up window appears (see Figure 16.49). This window confirms that you want to continue with this command. When you use any of the transformation commands you will break existing location constraints. Selecting No to this window cancels the translation command. Selecting Yes confirms that you want to break existing location constraints. Thus, if you had a document located one inch from the world coordinate position, using the translation command will override this constraint and will move the document to the new location. Once you select yes to the question dialog box the Translation Definition dialog box appears (see Figure 16.50).

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Figure 16.48 Translation Icon

Figure 16.49 Translation Question Pop Up Window

Figure 16.50 Translation Figure 16.51 Translation Vector Dialog Box Definitions There are three choices for Vector definitions used to define the translation (see Figure 16.51). The first is the Direction, distance vector definition. With this option, a selected edge will act as the direction vector, and the distance specified will move or translate the model. Note that the bottom front corner of the model is located at the 0,0,0 coordinate location. The direction field is highlighted and the bottom edge of the model is used as the direction vector with the translation distance of 2 (see Figure 16.52). Either positive or negative values will control the direction of the translation. In this example, a positive value was given and the part was moved or translated two inches to the right of where the model was originally located (see Figure 16.53). Had the negative value been given the model would have moved to the left two inches.

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Figure 16.52 Bottom Edge of the Model is Used as the Direction Vector

Figure 16.53 The Part Translated two Inches to the Right The second vector definition is the Point to point option. With this option, two points are selected to define both the direction and the distance of a vector that defines the translation of the part. The front, top, left corner of the part was chosen as the first point. The second point was the vertex on the top, front, right surface of the top prism of the part. After these two points are selected, the part is moved the distance between the selected points (see Figure 16.54). The third vector definition is the Coordinates option. Coordinates from the 0,0,0 position are given to translate the part. In Figure 16.55 a Z coordinate value of 2 inches was given to define the translation with the resulting translation of the part being moved up 2 inches above the 0,0,0 initial position.

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Figure 16.54 The Point to Point Vector Definition

ROTATION

Figure 16.55 The Coordinates Vector Definition The Rotation command (see Figure 16.56) is used to change the orientation of a part by rotating it around a specified axis at a specified angle. In Figure 16.57, the Rotate Definition dialog box is shown with the example part. The selected axis for the rotation is the edge formed by the intersection of the front plane with the left plane. The resulting rotation of the part is shown in Figure 16.58.

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Figure 16.56 The

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Figure 16.57 Rotating the Part Rotation Icon

Figure 16.58 The Rotated Part

SYMMETRY The Symmetry command (see Figure 16.59) is used to orientate the part 180° from its current position about a specified plane without making a copy of it. Figure 16.60 shows the Symmetry Definition dialog box. With this command,

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you need to specify a plane that you want the part to reorient about. In Figure 16.61, a reference plane is given. Figure 16.62 shows the part reoriented after the use of the symmetry command.

Figure 16.59 The Symmetry Figure 16.60 The Symmetry Definition Icon Dialog Box

Figure 16.61 The Symmetry Reference Plane

Figure 16.62 The Reoriented Part

MIRROR The Mirror command (see Figure 16.63) works very similar to the Symmetry command, except that it makes a copy of the part and also keeps the original part. Like the symmetry command, it requires a plane as a reference for positioning the copy of the part. Figure 16.64 shows the Mirror Definition dialog box. In the mirror definition dialog box, both the object to mirror and the mirroring element fields must be specified. In this example, (see Figure 16.65) only the mirror element needs to be specified because this is not an assembly.

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The mirroring element is the given plane reference element. Figure 16.66 shows the result of mirror the part.

Figure 16.63 The Mirror

Figure 16.64 The Mirror Definition Icon Dialog Box

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Figure 16.65 Specifying the Mirror Element

Figure 16.66 The Mirrored Part

EXERCISE 16.1 - DRILL INDEX In this tutorial, you will use reference elements, multiple pads, and relations to create the Drill Index. The use of the one and two directional Rectangular Patterns will be described and applied to show the functionality and efficiency of using rectangular patterns.

CREATING THE BASE FEATURE 1. Open your Startpart file and create the geometrically and dimensional constrained profile illustrated in Figure 16.67 on the XY (horizontal) positioning plane.

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2. From the sketch create a Pad, named top plate, with a thickness of .0625. The extrusion is in the positive Z direction. 3. Select the top plate pad from the specification tree.

Figure 16.67 The Constrained Sketch Part

CREATING THE ONE DIRECTION (FIRST) PATTERNS 4. Locate the Transformation Features tool bar and detach the Patterns toolbar from it and select the Rectangular Pattern icon (see Figure 16.68). 5. The Rectangular Pattern Definition dialog box appears. 6. Set the fields in the Rectangular Pattern Definition box to (see Figure 16.69).

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Figure 16.68 Pattern Toolbars

Figure 16.69 Rectangular Pattern dialog Box Parameters: lnstance(s) & Spacing Instance(s): 2

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Spacing: 0.75 in Reference element: top plane\Edge.? (the tangency line between the prism and the partial cylinder of the top plate) Object: top plate The rectangular pattern is to be in the negative Z direction. 7. Select OK and the rectangular pattern will be formed. Rename the pattern to middle plate RecPattern.1 (see Figure 16.70). 8. Repeat this procedure to create a second rectangular pattern spaced 1" below the top plate pad and name this pattern bottom plate RecPattern.2 (see Figure 16.71).

Figure 16.70 The Middle Plate

Figure 16.71 The Bottom Plate

CREATING ONE & TWO DIRECTION (FIRST & SECOND) PATTERNS 9. Select the top surface of the drill index and create a sketch of a circle. The location of the circle is the front left corner of the top plate and it is coincidental to the axis of the partial cylinder at the front left corner. The size of the circle is a diameter of .125. 10. Create a Pad named base columnPad.2 with the dimension of Up to last (see Figure 16.72).

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Figure 16.72 The Column Feature 11. Open the top plate sketch. 12. Add two reference dimensions that will be used to pattern the base column feature. Use the constraint icon and select the center point between the two arcs and right click before selecting the dimension and select reference from the pop-up menu. Notice both dimensions have parentheses which labels them as reference dimensions (see Figure 16.73).

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Figure 16.73 Adding the Relations to the Top Plate Sketch 13. Exit the pad sketcher and the pad command. 14. Select the base column feature from the specification tree and the Rectangular Pattern icon form the Pattern toolbar. 15. Set the fields in the Rectangular Pattern Definition box first direction to (see Figure 16.74): Parameters: Instance(s) & Spacing Instance(s): 2 Spacing: Relation (select the 2.25 reference dimensional constraint) Reference element: top plane\Edge.? (the tangency line between the prism and the partial cylinder of the top plate) Object: base column The rectangular pattern is to be in the negative Y direction.

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Figure 16.74 Rectangular Figure 16.75 The Completed Definition Dialog Box Rectangular Pattern of the Column 16. Set the fields in the Rectangular Pattern Definition box second direction: Parameters: Instance(s) & Spacing Instance(s): 2 Spacing: Relation (select the 8.25 reference dimensional constraint) Reference element: top plane\Edge.? (the tangency line between the prism and the partial cylinder of the top plate) Object: base column The rectangular pattern is to be in the positive X direction. 17. The completed rectangular pattern is shown in Figure 16.75. 18. Add a hole to the top surface of the drill index using the hole command 19. Constrain the hole as illustrated in Figure 16.76. 20. Use a two directional pattern to create the holes.

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21. Set the fields in the Rectangular Pattern Definition box first direction to: Parameters: Instance(s) & Spacing Instance(s): 9 Spacing: .9375 Reference element: top plane\Edge.? (the tangency line between the prism and the partial cylinder of the top plate) Object: hole The rectangular pattern is to be in the positive Y direction 22. Set the fields in the Rectangular Pattern Definition box second direction: Parameters: Instance(s) & Spacing Instance(s): Spacing: .75 Reference element: top plane\Edge.? (the tangency line between the prism and the partial cylinder of the top plate) Object: base column The rectangular pattern is to be in the negative Y direction. 23. The completed drill index is shown in Figure 16.77.

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Figure 16.76 The Dimensional Figure 16.77 The Completed Drill Constraints for Locating the Hole Index

EXERCISE 16.2- THE RIM In this exercise you will use circular patterns to create both positive and negative geometry. As with any computer application make sure that you "save early and save often". 1. Open the Rim part that you created with the Shaft command in chapter four. 2. Create a new sketch on the YZ (frontal) positioning plane composed of a circle with a diameter of 6.5 whose center point is coindental to the axis of the rim (see Figure 16.78). 3. Exit the sketcher and create a Pad with a Length: of 2.5 inches. 4. Rename this Pad to center lug (see Figure 16.79).

Figure 16.78 The Center Lug

Figure 16.79 The Center Lug Sketch

5. Use the Hole command to create a counter-bored hole on the planer surface of the center lug. The diameter of the smaller (tap hole) is .5". The diameter of the counter-bored hole is 1.5" with a depth of 2". 6. Select the Positioning Sketch icon to enter the sketch to position the center of the counterbored hole.

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7. Make your viewpoint isometric and zoom in on the center point of the hole. 8. Grab and move the center point to a vertical location on the surface of the center lug. 9. Use dimensional constraints to locate the point a radius of 2.5" from the axis of the rim. Select the axis of the rim and the center point of the counterbored hole right click and in the pop-up window select Vertical Measure Direction. 10. Repeat this procedure by selecting the rim axis and the center-point of the counter-bored hole and select then Horizontal Measure Direction and enter 0". This locates the center of the counter-bored hole 2.5" from the axis of the rim and the 0" of the Horizontal Measure Direction centers the hole. This procedure allows holes to be located without the use of construction geometry (see Figure 16.80). 11. Exit the hole sketcher and select OK to complete the hole (see Figure 16.81). 12. In the specification tree rename the hole to base lug hole.

Figure 16.80 The Counter-bored Positioning Sketch Hole

Figure 16.81 The Counter-bored Hole

CREATING A CIRCULAR PATTERN 13. In the specification tree select the base lug hole.

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14. From the Patterns tool bar select the Circular Pattern Icon (see Figure 16.82).

Figure 16.82 The Circular Pattern lcon 15. The Circular Pattern Definitions dialog box appears. 16. Set the fields in the Circular Pattern Definition box: Parameters: Instance(s) & angular spacing Instance(s): 5 Angular Spacing: 72 degrees Reference element: center lug Pad\Face.? (Pick the cylindrical surface of the center lug) Object to Pattern: base lug hole (see Figure 16.83) 17. Select OK in the Circular Pattern Definitions dialog box (see Figure 16.84).

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Figure 16.83 The Defining the Circular

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Figure 16.84 The Circular

Pattern of the Lug Counterbored Hole CREATING THE

Pattern

SPOKES 1. Select the sketch plane for the spoke as shown in Figure 16.85. 2. Use the Project 3D Elements and project the outer surface of the center lug and the inner surface of the rim. 3. Add a vertical axis line from the center axis of the rim. 4. Add two geometry lines.

Figure 16.85 The Sketch Plane for the Spoke 5. Constrain these lines at a 10 degree angle from the vertical axis line. 6. Use the Quick trim to turn off the lines and projected circles (see Figure 16.86) 7. Exit the sketcher. 8. Create a Pad from the sketch using the depth dimension of Up to Plane (see Figure 16.87).

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Figure 16.86 The Sketch of the Spoke Figure 16.87 The Dimension Up Spoke to Plane Defining the Depth of the 9. Use a circular pattern to create the remaining spokes (see Figure 16.88).

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Figure 16.88 The Settings for the Circular Pattern of the Spoke 10. Figure 16.89 shows the patterned spokes.

Figure 16.89 The Patterned Spokes 11. Add a 2' diameter simple through hole centered on the front plane of the center lug with a dimension of up to last (see Figure 16.90).

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Figure 16.90 The Completed Front Center Hole 12. Add a 3" diameter simple hole centered on the back plane of the center lug with a blind depth of 1.5" (see Figure 16.91).

Figure 16.91 The Completed Back Center Hole

17 CREATING MULTI-SECTION GEOMETRY INTRODUCTION In this chapter we will look at how to create Lofts. Lofts are also called swept features. In the previous two chapters, we saw how to create extruded 3D geometry with the Pad command and how to create revolved geometry with the Shaft command. There are some cases where the desired shape cannot be created by using the basic Pad and Shaft commands. Examples of these can be any 3D geometry with at least one curved surface. Consider the wing of an airplane. It is quite a complex shape with the cross-section of the wing changing at each step. Though it might be possible to model this using a combination of Pads, Pockets and Shafts, making changes down the road will be much easier if the wing were created with the Loft command. OBJECTIVES After completing this chapter you will be able to: 1. Identify and use the Point reference element 2. Identify and use the Line reference element 3. Identify and use the Plane reference element 4. Use the Reference Elements to assist in advanced 3D modeling 5. Identify the situations which use the use of the Loft tool as opposed to other sketch based features. 6. Use the Loft tool to create advanced 3D shapes 7. Describe the shape of the loft with advanced settings

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The Loft tool requires that you sketch out certain sections of the final shape, and then create a "skin" over the sections to make the solid model. In order to create the various sections, we need the help of Reference Elements in CATIA. Reference Elements are used while sketching sections to be used for creating lofts. To be better able to work with the Loft tool, let us look at Reference Elements within the Part Design workbench.

REFERENCE ELEMENTS The Reference Elements toolbar is not part of the default toolbar configuration in CATIA. You will have to turn it on first. 1. Right click anywhere on the toolbars and then turn on the Reference Elements (Extended) toolbar (see Figure 17.01).

Figure 17.01 Right Click on the

Figure 17.02 Reference Elements

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Toolbars Extended Toolbar 2. The toolbar should appear in the geometry area (see Figure 17.02). If you cannot see it, then drag out all the toolbars from the bottom right corner of CATIA workspace until you find it. As seen in the toolbar, there are three types of reference elements you can define within your part design. An important fact to remember is that reference elements can only be added outside of the sketcher mode. If you wish to use reference elements while sketching, you can simple use construction geometry to help you.

POINT REFERENCE ELEMENT The first icon is Point. This allows you to place a reference point anywhere in the geometry area. As we will see later, you can specify the exact location by means of entering co-ordinate values or its location with respect to any plan e, curve, or surface and so on. Upon clicking on the Point icon, the following dialog box will appear (see Figure 17.03). This is the dialog box which represents options of placing the point using x, y and z co-ordinates. The dialog box will change depending on the Point type you choose. The Point Type field lets you choose the method of placement of the reference point (see Figure 17.04).

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Figure 17.03 Point Definition Dialog Box

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Figure 17.04 Point Type choices

COORDINATES As seen in the dialog box (see Figure 17.05), the coordinates for x, y and z directions are user definable. The default reference or starting location for placing a Point is the origin. For example, entering 4 inches in the x field will place the Point at a distance of 4 inches from the origin towards the x direction. Once you have located your first Point, you can use it as the starting location for the next reference point.

ON CURVE To place a point on a curve, you can use any 2D entity such as a line, arc or curved edge defined by cylindrical geometry, fillets etc. A default point can be created at the starting point of the curve and a second point can be defined at a distance from the first point. The Reverse direction checkbox allows you to define the distance in the other direction. You can also create more than one point on the curve by checking Repeat object after OK. This will open a dialog box where you choose the number of instances and the spacing between them (see Figure 17.06).

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Figure 17.05 Point Type – Coordinates

Figure 17.06 Point Type- On Curve

ON PLANE Here you place the Point on any planer surface of constructed 3D geometry. The Point is once again referenced from another location, which is by default the origin. You can enter H and V values to place it a certain distance away from the origin. Or, you can select any other reference point as the origin and start from there (see Figure 17.07).

ON SURFACE In case where a curved surface is selected, then instead of H and V values, you will have to enter Direction and Distance from the reference origin point. The starting point is no longer the origin by default, but it changes to a point on the middle of the curved surface (see Figure 17.08).

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Figure 17.07 Point Type - On Plane

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Figure 17.08 Point Type - On Surface

CIRCLE CENTER One of the easiest point types to position, the Circle center dialog box has only one option: selecting a curved or circular edge to place the point at its center (see Figure 17.09).

Figure 17.09 Point Type- Circle Center

TANGENT ON CURVE This is used to place a point on an arc, circle, or edge of cylindrical geometry that is also parallel to any plane. First, select the curve on which you wish to place the point, next select a plane or line to specify the location of the point on the curve. In case a plane is chosen, its intersection point with curve will used to place the reference point. If more than one point intersects, then that many reference points will be placed (see Figure 17.10).

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Figure 17.10 Point Type- Tangent on Curve

BETWEEN In cases where you already have two points placed and would like to place any point in any location on an imaginary line joining the two points, you can use the Between option. The location of the third point can be defined by specifying the ratio between its distances from the first and second points (see Figure 17.11).

Figure 17.11 Point Type—Between

LINE REFERENCE ELEMENT The second icon on the Reference Element Toolbar is the Line element. Instead of placing just a Point, you can now draw a line using various construction types. A reference Line is used when working with surface modeling. As in the case with Point, a Line can be different types. A Line Type will be generated

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automatically depending on the first element selection (see Figure 17.12). The different possibilities are shown in Figure 17.13.

Figure 17.12 Line Definition Dialog Box

Figure 17.13 Line Type choices

POINT TO POINT This is one of the easiest methods to create a reference line. The possible selection points can either be reference points or end/intersection points. The Support option is used when you want the line to lie on the support surface, in which case it's called a Geodesic line. Otherwise the line created is the shortest distance between the two points. The Start and End values let you extend the line in either direction beyond the first and the second points (see Figure 17.14).

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Figure 17.14 Line Type - Point to Point

POINT-DIRECTION In this case, you have the option of creating a line, which passes through a point and is parallel to any other line, edge or linear element within the 3D geometry. The Support and Start and End values work the same way as in the last case (see Figure 17.15).

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Figure 17.15 Line Type -Point-Direction

ANGLE/ NORMAL TO CURVE This dialog box has three fields: Curve, Support and Point. After selecting these three elements, there will be a line passing through the point and tangent to the curve. Any angle values entered will rotate the line at that angle with respect to the tangency to the curve. The Support is a required selection in this case and must contain the selected curve. Checking on the Geometry, on the Support checkbox will map the line onto the surface thus creating a Geodesic line (see Figure 17.16).

Figure 17.16 Line Type -Angle/ Normal to Curve

Figure 17.17 Line Type - Tangent to Curve

TANGENT TO CURVE To use this option, first select a curve and then a point or another curve to define the tangency. In cases of tangency between two curves, more than one solution might be possible. Use the Next Solution button to cycle through them.

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If a second curve is selected or you are in Bi-Tangent mode, then a Support will have to be selected (see Figure 17.17).

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NORMAL TO SURFACE To use this option, select a reference surface and a point. The line created will be a vector passing through the point and will be normal to the surface. Specify Start and End values to describe the length (see Figure 17.18).

BISECTING To create a bisecting line, select any two non-parallel linear elements. A line splitting the intersecting angle into two halves will be created. Cycle through the solutions using the Next Solution button (see Figure 17.19).

Figure 17.18 Line Type - Normal to Bisecting Surface

Figure 17.19 Line Type-

PLANE REFERENCE ELEMENT This reference element is perhaps the most used of all three and is a very powerful tool. The three default sketch planes are located at the origin at right angles to each other. Now you can create a user defined plane at any location or orientation with respect to those planes. You can even use a surface from other geometry as reference (see Figure 17.20).

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The list of available plane types is shown in Figure 17.21.

Figure 17.20 Plane Definition Dialog choices

Figure 17.21 Plane Type Box

OFFSET FROM PLANE To create a reference plane at an offset distance, first select a plane and then enter an offset value. A new plane will be created at the specified distance. You can reverse the direction of the plan creation with the Reverse Direction button. Checking the Repeat Objects after OK box will give you the option of creating more than one plane at equal spacing after the first (see Figure 17.22).

PARALLEL THROUGH POINT Use this to create a plane parallel to another plane while passing through the selected point (see Figure 17.23).

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Figure 17.22 Plane Type - Offset Figure 17.23 Plane Type - Parallel From Plane Through Point

ANGLE/NORMAL TO PLANE To create a plane with this type, you have to first select a reference plane and then a rotation axis. The axis can be any other line or it can also be the axis of a cylinder. To select the axis of a cylinder, keep the SHIFT key pressed while moving the mouse pointer over the element. Enter an angle value to rotate the plane with respect to the reference plane. You can create multiple planes at an angle from the initial plane (see Figure 17.24).

Figure 17.24 Plane Type -Angle/Normal to Plane

THROUGH THREE POINTS Select any three points in space to create a plane passing through them. You can now drag the plane to the desired location (see Figure 17.25).

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Figure 17.25 Plane Type - Through Three Points

THROUGH TWO LINES To create a plane, select any two lines. The plane passing through the two line directions is displayed. When these two lines are not coplanar, the vector of the second line is moved to the first line's location to define the plane's second direction. To ensure that both the lines are on the same plane, check the Forbid non-coplanar lines checkbox (see Figure 17.26).

THROUGH POINT AND LINE Use this to create a plane passing through both a line and a point (see Figure 17.27).

Figure 17.26 Plane Type - Through Figure 17.27 Plane Type - Through Two Lines Point and Line

THROUGH PLANAR CURVE Use this to create the plane that contains a planar curve (see Figure 17.28).

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Figure 17.28 Plane Type - Through Planar Curve

NORMAL TO CURVE Use this to create a plane normal to any selected point on a curve. The default point on the curve is the middle point on the curve (see Figure 17.29).

Figure 17.29 Plane Type - Normal to Curve

TANGENT TO SURFACE Use this to create a plane that is tangent to a surface. Select a point on the surface where you want to define as the point of tangency (see Figure 17.30).

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Figure 17.30 Plane Type - Tangent to Surface

EQUATION The equation of a plane in space is defined as Ax+By+Cz=D. All four variables can be entered. You can also select the point you wish to pass the plane through. In this case, the D component would be grayed out. Use the Normal to compass button to position the plane perpendicular to the compass direction. Use the Parallel to screen button to apply parallel to the screen for the current view (see Figure 17.31).

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Figure 17.31 Plane Type – Equation Figure 17.32 Plane Type - Mean Through Points MEAN THROUGH POINTS Use this to create a mean plane between three points. The selected points can be removed or replaced by another point (see Figure 17.32). Now that you can create reference points, lines and planes, we can move on to discussing the Loft tool.

LOFT The Loft icon is located on the Sketch Based Features toolbar (see Figure 17.33). Clicking on it will bring up the Loft Definition dialog box (see Figure 17.34). But before we can start making any lofts, we will have to define at least two closed planar sections.

Figure 17.33 Loft icon

Figure 17.34 Loft Definition Dialog Box For examples in this book, all sections are created on reference planes. In Figure 17.35, a plane was created as an Offset from the zx plane. It is parallel to the zx plane and at distance of 4 inches.

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Figure 17.35 Reference Plane Created Parallel to ZX Plane Using the sketcher, two independent planar sections are drawn on the zx plane and the reference plane. Remember that the section has to be closed and cannot contain any orphan elements. The Loft command will not work with open loops. As seen in Figure 17.36, an elliptical and a circular section have been created on each of the planes.

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Figure 17.36 Closed Planar Sections After creating the sections, start the Loft command and select both the sketches one by one. As you can see in Figure 17.37, the sketches are added to the list of sections. The user can check the sequence of selection by looking at how CATIA names them: Section 1, Section 2 and so on. Each of the curves now has a Closing Point and an arrow tangent to the curve and on the same plane. The direction the arrow points is the direction in which the "skin" will be applied from. Clicking on the arrow will reverse its direction, but it will also "fail" the loft since the extrusion is now at an acute angle.

Figure 17.37 Selected Sections to Loft You can do a quick preview to check whether the loft is valid, or simply click on the OK button to exit the command. Figure 17.38 shows the completed loft between an ellipse and a circle.

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Figure 17.38 Successful Loft Now that we know how a loft is created, let us look at some of the advanced options within the Loft dialog box. As you can see in Figure 17.39, the dialog box has four tabs.

Figure 17.39 Loft Definition Options

GUIDES Guides are sketch elements, which can be used to control the shape of the loft. Figure 17.40 shows a spline sketched onto the yz plane. It is necessary for the spline to intersect both the profiles to work. Our spline is tangent to both the curves and bent downwards at the middle. The final sketch will look like Figure 17.41.

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Figure 17.40 Sketched Spline

Figure 17.41 Isometric View of the Sketches Now we can redo the loft command and use the newly sketched spline as a Guide. The definition box should look like Figure 17.42. Remember to click on the" ... " under the Guide tab before selecting the spline. Otherwise CATIA will try to add it as a section and return an error. The lofted geometry will resemble Figure 17.43.

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Figure 17.42 Defining a Guide

Figure 17.43 The Completed Loft

Figure 17.44 Spine Using a Guide

SPINE The Spine option works similar to the Guides. But a spine does not need to intersect the profile. As seen in Figure 17.44, a spline is sketched on the yx plane and it spans from the center of the ellipse to the center of the circle.

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You can see the completed loft after using the sketched spline as a spine in Figure 17.45. If the Computed Spine checkbox is checked, then CATIA will automatically compute a spine and our spline will be removed from selection.

Figure 17.45 The Completed Loft Using a Spine

COUPLING The Coupling settings control how the loft interacts with the different sections. It is beyond the scope of this book to list the usage of each setting. However, it should be known that when using sections with unequal number of vertices, only the Ratio coupling would work.

RELIMITATION Suppose you use a spine, which extends beyond the last section to shape the loft. If both the Loft Relimited on Start Section and End Section are turned on, then the loft will be limited to these two sections. If they are turned off, the loft will extend to the end of the spine.

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Figures 6.46 through 6.48 are examples of different types of lofts:

Figure 17.46 A shape of a wing created with 6 sections using the default loft

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Figure 17.47 The Same Wing But With a Curved Spine

Figure 17.48 A 6 Point Coupling Added to Further Define the Shape

EXERCISE 17.1 1. Open your CATIA file named startpart and save it to the correct assignment number. 2. Select the zx (profile) plane and enter into Sketcher. 3. Sketch a circle with a diameter of 2 and locate it at the world coordinate position (0,0,0). 4. Exit out of sketcher, and start a sketch on the xy (horizontal) plane. 5. Draw a circle and a vertical construction line.

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6. Constrain the circle so it is tangent to the vertical axis and the center is coincident to the horizontal axis. 7. The vertical construction line should be coincident through the center of the circle as shown in Figure 17.49. 8. Trim the circle so you only have the top left quarter as shown in Figure 17.50. 9. Exit out of Sketcher

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Figure 17.49 Constrained Circle

Figure 17.50 Trimmed Circle

ADDING A SECOND DATUM PLANE 10. Select the Plane icon. 11. Under plane type, select "parallel through point". Your reference should be the yz (frontal) plane and the point is the end of your drawn spline (see Figure 17.51). 12. On this plane, create another circle with a diameter of 2, concentric with the endpoint of your spline. Note: Pick Plane in the specification tree and then pick Sketcher Icon. Exit Sketcher

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Figure 17.51 The Plane Dialog Box

CREATING THE SHAPE OF THE PIPE 13. Select the Loft icon. 14. Choose the two, sketched circles, and then select the spine tab. Choose the quarter-circle sketch and click OK (see Figure 17.52). NOTE: if you receive an error message and the loft is twisted click on one of the directional arrows so that they point in the same direction. 15. On each end of your pipe, sketch 1.5 diameter circles concentric to the 2 diameter circles. 16. Create a removed loft between these two circles using the same method as above. You can use the same spine by clicking on its name in the specification tree.

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Figure 17.52 The Multi-section Definition Dialog Box.

CREATING THE END 17. Start a sketch on the zx (profile) plane. 18. Select the Project 3D Elements icon on the Operation toolbar (see Figure 17.53) and then select the inner radius of the pipe projection parallel to the projection plane. This circle is now an object in this sketch. 19. Construct a circle 3 in diameter concentric with this projected circle. Your sketch should look like Figure 17.54. 20. Exit out of sketcher and create a .25 pad from this sketch.

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Figure 17.53 Operation Toolbar Figure 17.54 Constrained Outer Circle PLACING THE HOLES 21. Place a 0.25 diameter hole 0.5 from the outer edge using a 2.5 diameter construction circle (see Figure 17.55). 22. Use a circular pattern using Instance(s) and angular spacing to create the remaining three holes on the end. Your reference element should be the axis of the larger circle. 23. Repeat this procedure for the other end and your completed part should look like Figure 17.56.

Figure 17.55 Constraining the Hole

Figure 17.56 Completed Part

EXERCISE 17.2 In this exercise, you will create an Airfoil using the Multi-section command. The airfoil has identical sections at certain distance from each other. Thus, we can reuse one sketch and scale it down for the other section. 1. Open your CATIA file named startpart and save it to the correct assignment number. 2. Right click on any of the tools to the right of the main window and make sure that "Reference Elements (Extended)" is selected. 3. Select the yz (Frontal) plane and enter the Sketcher.

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4. Create three circles, one standard line and one construction line as shown in Figure 17 .57.

Figure 17.57 Geometric Shapes for the First Profile

5. Locate the 0.9 radius circle to (0,0,0) world location. 6. Give both lines horizontal constraints. 7. Create tangency relations between the circles and line shown in Figure 17.58.

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Applied Geometry for Engineering Design Figure 17.58 Tangency Between the Circles

8. Make the horizontal construction line coincidental to the center of the 3.6 and 1.8 radius circles (see Figure 17.59).

Figure 17.59 Horizontal Construction Line Coincidental to the Center of the Circles 9. Make the 3.6 and 1.8 radius circles tangent to each other (see Figure 17.60). 10. Create a 39.4 radius circle and make it tangent to the 0.9 and 3.6 circles. The sketch should appear like Figure 17.61.

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Figure 17.60 Circles Tangent to Each Other

Figure 17.61 Constrained Sketch 11. Define the horizontal measure direction between the 0.9 and 1.8 circles as 23.8 (see Figure 17.62).

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Figure 17.62 Defining the lengths 12. Use the Trim and Quick Trim feature to make the sketch look the same as Figure 17.63. 13. Exit the sketcher mode and make sure the sketch is valid.

Figure 17.63 Completed Sketch 14. Reopen the Sketcher and highlight the entire sketch by right clicking any selected portion and selecting "Copy" (see Figure 17.64).

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Figure 17.64 Copying the Sketch 15. Exit the Sketcher and select the Plane tool in the Reference Elements group (see Figure 17.65). 16. Select the yz plane on the Specification Tree to assign the reference plane parallel to it. Set 150 inches as the offset. Click OK and notice that "Plane.1" is added to the Specification Tree. 17. Select the newly created plane and enter the Sketcher. 18. Click "Edit" from the top tool bar and then click "Paste." 19. While the sketch is highlighted, select Insert, Operation, Transformation, and Scale. In the Scale Definition window, un-select the duplicate mode option (see Figure 17.66).

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Figure 17.65 Plane Tool

Figure 17.66 Scale Definition Window

20. Next, click on the (0,0,0) world coordinate as a scale reference point. Move your mouse to the right and left-click when Scale definition box is at 0.7 (see Figure 17.67).

Figure 17.67 Scaling the Sketch 21. Exit the Sketcher and select PartBody on the Specification Tree. 22. Next, click the Multi-section icon, which is a member of the Sketch-Based Features toolbar (see Figure 17.68). The multi-section command develops 3D geometry by creating smooth transitions between various 2D sketch profiles.

Figure 17.68 Multi-sections lcon 23. The Multi-section Definition dialog box will appear. Select Sketch.2 first and then Sketch.1 from the Specification Tree (see Figure 17.69).

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Figure 17.69 Multi-section Definition Dialog Box 24. Each profile should now have two red descriptions showing the section number and the closing point for the loft (see Figure 17.70).

Figure 17.70 Two Closed Profiles 25. To avoid creating a cusp with the multi-section command, the closing points must be in the same relative location and direction on each profile. The error

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Applied Geometry for Engineering Design message you would receive is shown in Figure 17.71. Right click on Closing Point2 and select replace (see Figure 17.72).

Figure 17.71 Multi-section Error Message

Figure 17.72 Selecting Remove 26. Magnify the Section2 and right click on the correct relative point of the sketch (see Figure 17.73). Select Replace Closing Point from the menu and click on the place where the new point should be (see Figure 17.74). Then click OK on the Point Definition and Multi-section Definition window. If done correctly, no cusp errors should occur.

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Figure 17.73 Right Clicking on the Correct Point

Figure 17.74 Selecting a New Location For the Point 27. A successfully created geometry should appear the same as Figure 17.75.

Figure 17.75 Completed Multi-section Geometry

SUMMARY In this chapter, we built on our previous know ledge of 3D tools and applied it to the creation of multi-section geometry. Before geometry can be created using the Multi-section geometry command the three dimensional reference elements must be defined. This chapter explained the definitions and uses of Reference Points, Lines, and Planes. Different examples were given where the Multi-section command would be a more appropriate option compared to the shaft, pad, or pocket commands. Lastly, you were shown how to make advanced 3D shapes using multi-section sketch profiles and how to describe these shapes with advanced settings.

19 CREATING DRAWINGS IN CATIA INTRODUCTION Earlier, sketched geometry was constrained and used to create solid models. The Pad command was used to create extruded solid geometry and the Shaft command was used to create revolved solid geometry. Both positive and negative geometry were used to create features of parts using both extrusion and revolution techniques. In this chapter, views will be extracted from the solid models to create orthographic representations. The development of section and pictorial views will also be covered. Dimensions and annotations will be added to the views so that the size and location of the part features are described. The drawing workbench in CATIA is quite extensive and the intent of this chapter is to give you an overview of its functionality. To become proficient in the drawing workbench is beyond the scope of this book.

OBJECTIVES After completing this chapter you will be able to: 1. Understand associativity between drawings and models. 2. Link drawings to models in CATIA. 3. Use view tools with drawings. 4. Create and modify dimensions in CATIA. 5. Create and modify text in CATIA. 6. Create views in CATIA. 7. Manipulate drawing views in CATIA.

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ASSOCIATIVITY Associativity is the relationship between drawings and models. There are three types of associativity; none, one-way, and two way. When there is no associativity between the model and the drawings, if the model is changed the drawings do not change to reflect the changes in the model. In one-way associativity dimensional changes made to the model will be reflected in the views generated from the model. If a cylindrical feature of a model is made larger by changing a dimensional constraint in the sketch of the model, the views of the drawing that are associated to the model will reflect the change when they are updated. With two-way associativity dimensional changes made in the drawing will result in changes made to the model and changes made to the model will change the drawing. CATIA has one-way associativity, thus changes made to the model will be reflected in changes made to the drawing when the drawing is updated.

LINKING THE DRAWING TO THE MODEL The drawing will always be linked to the model from which the views were extracted. If the drawing cannot find the model it is linked from it will display the Open dialog box (see Figure 19.01) to inform you of this problem. The views of the drawing may display, but if you try to add dimensions the Dimension Creation dialog box will tell you that a link between the active view and the document (model) cannot be found and dimensions cannot be added (see Figure 19.02). Always make sure that the links between the drawings and the models are never broken. One easy way to make sure that the links are not broken is to always place the model files and the drawing files in the same subdirectory and keep them together in this subdirectory. If you would create the drawing in Laboratory A the drawing links reference back to a specific drive or subdirectory in Laboratory A. If you copy the model and associated drawing file onto a CD, the drawing file will still try and find the model from the Laboratory A. If this occurs you will not be able to add dimensions or the dimensions may be missing from the drawing. In industry, a PDM (product data management) system would probably make certain that the links are established and maintained. For the purposes of the drawings that will be created later make a subdirectory where both the model file and the drawing file will be stored together and make sure that you are linking the drawing to the model in this subdirectory.

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Figure 19.01 Open Dialog Box

Figure 19.02 Dimension Creation Dialog Box

DRAFTING WORKBENCH DESIGN PROCESS The first step in the Drafting Workbench is to create views. After you have your views placed into the drawing sheet, you will need to adjust them by changing the scale of the views or by moving them into the correct position. Once you have the views finalized, the next step is to create the dimensions needed to detail the views. You need to double check and make sure the drawing has the necessary dimensions needed to manufacture a part. After you have applied all the necessary dimensions, the next step would be to apply any annotations or text needed to describe how the part is to be made or how to assembly it. In an assembly drawing, typically you would also include a bill of materials, which lists all the parts necessary to create the assembly. Over the next few sections you will get an overview on how to create and modify views, text, and dimensions. VIEW TOOLS Views are an integral part of drafting. CATIA offers many different options concerning the layout and type of views. Almost every option can be found under the Views toolbar shown in Figure 19.03. Selecting the expansion arrow on the first icon from the left exposes the "Projections" toolbar (Figure 19.04). The most common projections are Front, Projection, Auxiliary, and Isometric.

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These icons are the first, fifth, sixth, and seventh icons, respectively. The projection tools effect the orientation and relative locations of the part on your two-dimensional drafting sheet. The Front option is used to create the base or first view for the drawing. The Projection option is used to create other views based off of the Front view. The Auxiliary option allows you to show the true size and shape of an inclined surface. The Isometric option is commonly used to show a 3D view of the part in the upper right-hand corner of a drawing.

Figure 19.03 Views Toolbar

Figure 19.04 Projections Toolbar

On the Views toolbar, the section view icon is expanded (Figure 19.05). The Offset Section View and Offset Section Cut are the first and third icons in the Sections toolbar. These options create section views of a part by a user-defined cutting line or cutting plane.

Figure 19.05 Sections Toolbar The Detail View (see Figure 19.06) allows a user to create a viewing box on an area that you want a blown-up image of to see more detail. The View Creation Wizard (Figure 19.07) is a tool that can create and place views on a specified drafting sheet. This option will be used extensively in the first exercise.

Figure .8.06 Detail View

Figure 19.07 View Creation Wizard

CREATING AND MODIFYING DIMENSIONS After your views are aligned according to the applicable ANSI or ISO standards, you must dimension the views. Dimensioning can be completed by using the Dimensioning Toolbar. (see Figure 19.08) This toolbar is a grouping of

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twentyone options that range from lengths and distances to threads and chamfers. The first three options in the Dimensioning Toolbar are shown in Figure 19.09. These icons create dimensions, cumulated dimensions, and stacked dimensions respectively. Using associativity, these tools take constraints from the original part and turn them into dimensions on the drawing.

Figure 19.08 Dimensioning Figure 19.09 Associativity Toolbar Dependent Dimensioning Tools The next grouping of icons allows the user to control how the views are dimensioned. Figure 19.10 shows the Length/Distance, Angle, Radius, and Diameter dimensioning tools, respectively. The use of the user controlled dimensioning tools is like constraining geometry in the Part Design sketcher. Features will be automatically dimensioned by CATIA, but these values can be changed in value or position by double clicking on the dimension. Right -clicking a dimension and selecting Properties will provide more options for modification. Dimension lines, texts, fonts, and tolerances can be changed in almost any way.

Figure 19.10 User Controlled Dimensioning Tools

CREATING & MODIFY TEXT C ATIA V5 integrates Windows functionality to allow you to create or modify text in several different ways. You are most likely familiar with Microsoft Office functions. The Text toolbar located along the top is almost identical. In Figure 19.11, you should recognize many similar tools such as Font Style, Font Size, Bold, Italics, Underline, Align Right, Center, Left, etc.

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Figure 19.11 Text Properties Toolbar The Annotations toolbar (Figure 19.12) contains several different options, but let's look at some of the most common tools located on it. The first icon is the Text options icon. When selected, you will be able to create a text box that can be placed anywhere on the drafting sheet. This text box can be moved or expanded by grabbing a boundary or using window handles, respectively. By clicking Text's drop down arrow, you will reveal more text annotation tools (see Figure 19.13).

Figure 19.12 Annotations Toolbar

Figure 19.13 Text Toolbar Options

Then next icons covered are the Text with Leader icon and the Balloon icon. The Text with Leader command results in a text line with a leader pointing to a required are (see Figure 19.14). The Balloon tool is good to use for numbering different items on your drafting sheet. An example of a balloon being used is given in Figure 19.15. Note that other characters besides numbers can be inputted into the balloons. Balloons and text with leaders can be modified much like dimensions. By right clicking and selecting Properties, fonts, texts, and feature properties can be modified.

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Figure 19.14 Text With Leader Example

Figure 19.15 Balloon Example

EXERCISE 19.1 CREATING VIEWS The first step in the creation of a working drawing in CATIA is developing the different views required to accurately describe a part. The views that will be created are based on the part model that you select. These views will then be placed on a specified size drawing layout. CATIA does not come with any generic title blocks thus; any title blocks will have to be created. In this tutorial, a title block will be provided on which you will place your views of the model.

VIEW CREATION 1. Make a copy of exercise 3.1 (Gasket) model file and place it into a subdirectory where your drawing file will be stored. This subdirectory will be the week subdirectory that this tutorial is assigned. 2. Open the model from which you wish to create the drawings from. In this example open Exercise 3.5 (Gasket), which you created as a model in Chapter 3. 3. In the File pull down menu choose the Open option and locate the drawing named ANSI B Landscape (the location of this file will be given to you in class).

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4. Use the SaveAs command to save the ANSI B Landscape drawing file into the subdirectory where the copy of the Pump Gasket solid model is stored as the correct file name. 5. Locate and place the Views toolbar into a landscape position and select the View Creation Wizard option (see Figure 19.16). 6. The View Wizard (Step 1/2): Predetermined Configuration dialog box appears (see Figure 19.17).

Figure 19.16 The View Creation Wizard Button

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Figure 19.17 The View Wizard (Step l/2) 7. Notice on the left side of this dialog box several different preset view configurations are available. Choose the top one which will generate the front, top, and right side views and then select the Next button. 8. The View Wizard (Step 2/2): Arranging the Configuration dialog box appears. This dialog box allows additional views to be added to the views already generated. For this example, select Finish to exit the dialog box without adding any additional views. 9. Notice that no views are displayed. Before the views can be displayed, the desired front view must be selected from the model. Note the instructions that are given on the command line. 10. Under the Window pull down menu change the window so that the Pump Gasket model is the active window. 11. Move your cursor over the top planer surface of the pump gasket until it highlights. Notice that the Orientated Preview window appears in the lower right hand comer of the screen (See Figure 19.18).

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Figure 19.18 The Orientated Preview Window 12. Select the planer surface and a view of the model will be placed on the drawing. Once this surface has been selected you will be returned to the drawing window. 13. Notice that there are three green rectangular boxes that represent the views of the part. As you move your cursor from one view to another the part will

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be displayed. Also, notice that there is a circular blue compass tool with arrows on it. This tool allows you to rotate the front view into a new orientation (see Figure 19.19).

Figure 19.19 The Front View Orientation Compass 14. The orientation of the front view in Figure 19.19 is in the correct orientation, but use the different arrows on the blue compass tool to experiment with changing its orientation. Once you have returned the front view to the correct orientation pick the center circle to accept this orientation.

VIEW MANIPULATION The three views have now been successfully created but their scale may not allow the views to fit onto the drawing sheet. By selecting the view frame that surrounds the view and then selecting the right mouse button and choosing the properties option changes can be made to the selected view.

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15. The front, top, and side views were chosen from the View Wizard when the views were created because this was the easiest way to quickly create the views. In this example, only two views are needed to describe the object. Thus pick the view frame of the top view and delete it by selecting the Delete key. Since it is very easy to delete views, many times it is to use the default view option from the View Wizard and delete the unnecessary views than it is to try to create the desired views one at a time. 16. The front and right side views now remain and if their scale wss too large to fit onto the drawing sheet or too small to be viewable the schal would have to be changed. Select the front view by selecting the view box. Depress the CTRL key and select the side view and then hit the right mouse button. Select the Properties option and the Properties dialog box will appear (see Figure 19.20).

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Figure 19.20 The View Properties Dialog Box 17. The two main areas of the Properties dialog box are the Scale and Orientation fields and the Dressup buttons. 18. In this exercise the scale of the views are fine thus leave the Scale field at 1: 1 or full scale. Changing the view scale will allow views to fit onto the drawing sheet and allow enough room to add dimensions and notes to the drawing. 19. Review the options available with the Dressup buttons. The Dressup but tons control the display of hidden and center lines and other view options.

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Make sure that the Hidden and Centerline options are selected. 20. Once these changes have been made, select OK and turn off the properties dialog box. 21. Select the view frame of the front view and move it into the general left portion of the drawing sheet. Note that the right view also moves with the front view. This occurs because the front view is the parent view and the side or child view follows it. These views will always be in alignment reflecting orthographic drawing standards. 22. Next select and move the right view onto the drawing sheet so the views are approximately in the same position as Figure 19.21.

Figure 19.21 The Approximate Location of the Front and Right Side Views

ADDING CENTER LINES TO THE VIEWS Although some of the centerlines will automatically be generated when the views are created, many centerlines will not and will have to be added manually. 23. Zoom in on the front view and notice the bolt circle and the angled centerlines for locating the .340 holes are not present and will have to be manually added.

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24. Locate the geometry creation toolbar. It is identical to the Geometry Creation Toolbar used in the sketcher. 25. Use the circle command and draw a bolt circle whose center starts at the center of the front view and whose radius is the center point of one of the holes in the lugs (see Figure 19.22).

Figure 19.22 Manually Figure 19.23 Modifying the Line Adding the Bolt Circle to the Properties of the Circle Drawing 26. Move the cursor over this line and select it with the right mouse button. The Properties Dialog box will appear. 27. In the Line type field of the properties dialog box change the line type from a solid line (1) to a centerline (4). In the Thickness field change the thickness of the line from 2 (.35) to 1 (.13) and click OK (see Figure 19.23). Notice the circle will now appear as a centerline.

28. Now the angular center lines need to be added to specify the angular location of the lugs. Use the Line command from the Geometry Creation toolbar and construct lines from the center of the Pump Gasket through the centers of the lug holes. Make certain that the solid black circle appears signifying the line is passing through the center of the Gasket and through the center of the lug holes before selecting the point and extending the lines beyond the circles. If you have trouble snapping to the center of the circles

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zoom in until you can select the center points of each circle (see Figure 19.24).

Figure 19.24 Adding the angular Center Lines to the Sketch

Figure 19.25 Changing the Properties of the Angular Center Lines

29. Now select all of the angular lines and change their line type from a solid line (1) to a centerline (4) and the line thickness from 2 (.35) to 1 (.13) (see Figure 19.25). Note: use the Ctrl key and select all the lines and change the linetype properties all at once.

ADDING DIMENSIONS TO THE PUMP GASKET The next few steps will illustrate how different types of dimensions can be added to drawings. There are endless ways that dimensions can be added and set up in CATIA. The examples below will just give an overview of how dimensions are added to drawings. 30. Find the Dimensioning toolbar and expand the first button and remove it so that the Dimensions tool bar is shown (see Figure 19.26).

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Figure 19.26 The Dimension Toolbar It is good dimensioning practice to dimension all of the solid geometry first, then the negative geometry of a part, followed by locating the different features using location dimensions. 31. Make the Diameter Dimensions option active from the Dimensioning toolbar by double clicking on it with the left mouse button (see Figure 19.27).

Figure 19.27 The Diameter Dimensions Option 32. Typically it is standard practice to dimension the positive cylinder in the rectangular view but it this case it is better to dimension the positive cylinder in the circular view for easier visualization of the dimension. Select the geometry circle of the positive cylinder with the with the left mouse button. The numerical dimension and the dimension line will appear. Move the mouse to locate the dimension in a desired location and pick this spot with the left mouse button to place it. 33. Turn off the Diameter Dimensions option and place the cursor over the numerical value and drag it into a different location. The location of dimensions can be easily changed by just dragging them to a different location with the mouse (see Figure 19.28).

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Figure 19.28 Changing the Location of a Dimension 34. Docked on the top menu bar should be the Dimension Properties menu. Figure 19.29 shows this menu undocked and on the far left side are different dimension line options.

Figure 19.29 The Dimension Properties Toolbar 35. Notice that the circle dimension did not have a leader line. Select the dimension and under the Dimension line option choose the second option from the top. This will add a leader to the end of the dimension line (see Figure 19.30). 36. Repeat this procedure and add the diameter dimension for the bolt circle (see Figure 19.30).

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Figure 19.30 The Added Bolt Circle Dimension and Leader Lines 37. From the Dimensions toolbar select the Radius Dimensions option (see Figure 19.31).

Figure 19.31 The Radius Dimension Option 38. Pick the radius of the bottom lug and place the radial dimension. 39. Add the leader line. The radial dimension will appear as but there are three of these radial features of the same size on this drawing. It is common practice to only dimension one of arcs and place the number required followed times sign in front of the dimension text (3 X R). 40. Move the cursor over the dimension number and click the right mouse button. Select from the popup menu the properties option and the Properties dialog box will appear (see Figure 19.32).

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Figure 19.32 Dimension Properties Dialog Box 41. 45. Notice there are several tabs available in this dialog box. If it is not the current tab, select the Dimension Text tab. 42. In the Prefix- Suffix field the R for radius is present. Move your cursor to the left of the R and add "3X" in front of the radius without any spaces and select OK. In the drawing the dimension should read 3 X R (See Figure 19.33). You are encouraged to review and test the other options available under the different tabs of the dimension Properties dialog box. Not all of the different tabs will be covered, but examples will be given of specific ones, as they are needed.

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43. Use the Dimensions command from the Dimensions toolbar (see Figure 19.33) and dimension the thickness of the Gasket in the right side view (see Figure 19.34).

Figure 19.33 The dimension Command from the Dimensions Toolbar

Figure 19.34 The Thickness Dimension Added to the Gasket Once all of the positive features of the view have been placed the size of the negative features should be given on the drawing. 44. Use the Diameter Dimensions option and select the hole on the upper right lug to add the dimension. Right click on the dimension and go into the

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dimension Properties dialog box. Select the Dimension Texts Tab and under the Associated Texts choose the field that is to the left of the Main Value field and enter "3X" and select OK (see Figure 19.35).

Figure 19.35 Adding the "3X" to the Lug Hole Dimension 45. Add the diameter dimension for the center hole. Angular dimensions will be used to locate the positive and negative geometry. 46. The Angle dimensions icon is located on the dimensions toolbar (See Figure 19.36).

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Figure 19.36 The Angle Dimensions Option 47. Activate the Angle Dimensions command and select the vertical and angular center lines and place the dimension. Edit the text properties and add 3X in front of the 120 degree angle to communicate that all the angles are equal (see Figure 19.37).

Figure 19.37 Adding the Angle Dimensions to Position the Hub 48. Finally, the fillet and round annotation needs to be added to the drawing. Figure 19.38 shows the Annotations toolbar. From the Annotation toolbar select the Text option and pick an open area in the drawing with the mouse. Notice the Text Editor window is displayed along with Text Editor dialog box (see Figure 19.39).

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Figure 19.38 The Annotation Figure 19.39 Text Editor Dialog Box Toolbar 49. All dimensions should be in uppercase letters so verify that the Caps Lock is on before typing the fillets and rounds note. Enter the text, "FILLETS & ROUNDS R.25" has been entered select OK. The text can be move to any position by selecting its view frame and dragging it to the desired position (see Figure 19.40).

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Figure 19.40 Dragging the Annotation Note into a Desired Location

ENTERING INFORMATION INTO THE TITLE BLOCK Title blocks are used to keep important information about the drawing. Just basic information will be entered into the title blocks for use in this book. 50. Zoom in on the title block and double click on the "STUDENT NAME" text and notice the Text Editor dialog box appears. Change the text to your name. Be sure to use all upper case letters. 51. Change the scale field from X/X to 1:1. 52. Change the drawing from "XXXXXX" to the correct assignment number.

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53. Finally change the sheet from "X OF X" to 1 of 1 (see Figure 19.41).

Figure 19.41 .Editing the Title Block Text

MODIFYING THE DIMENSIONAL VALUES As you may have noticed many of the dimensions may have been represented on the drawing in milimeter values when they should have been inch representations. The following steps describe how to change the dimensional values to inch representations. 54. Use the cursor and window selection tool to select all of the dimensions in one view. They should all turn red. 55. From the Numerical Display Description pull down menu on the Dimension Properties toolbar select the NUM.INC option (see Figure 19.42).

Figure 19.42 Changing the Numerical Display Description

MODIFYING THE MODEL Remember that CATIA uses one-way associativity thus any changes made to the model will be reflected in the drawing of it. 56. Change the window to the model window of the Gasket. 57. Double click on the Base Feature Pad in the Specification Tree. 58. In the Pad Definition dialog box change the length (thickness) from .08 to .25. 59. Select OK to exit the Pad Definition dialog box.

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60. Double click on the Center Hole feature in the Specification Tree. 61. In the Hole Definition dialog box change the diameter from 3 to 1. 62. Switch to the drawing and find the Update toolbar/button (see Figure 19. 43). When the Update button is black then the drawing needs to be updated because of changes made to the model. 63. Select the Update button and notice that the thickness of the part and the center hole diameter change to reflect the revisions to the model. Try and change other dimensions in the model such as dimensional changes in the sketcher and see how these reflect in changes to the drawing.

Figure 19.43 Update Option

ADDING A PICTORIAL VIEW TO THE DRAWING Many times it is helpful for the correct visualization of a part to add a pictorial view of it on the drawing. 64. While in the drawing workbench select the Views toolbar pick the Isometric View option (see Figure 19.44).

Figure 19.44 Selecting the Isometric View 65. Note the command line states you must select a reference plane on a 3D geometry. Thus change to the part workbench. 66. Change the viewpoint of the part to Isometric (see Figure 19.45).

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Figure 19.45 Changing the Viewpoint of the Gasket to Isometric 67. The pictorial view of the Pump Bracket will appear on the drawing. 68. Select the view frame of the pictorial view with the right mouse button and select the Properties option. 69. Verify the view properties scale of 1:1. 70. Also in the Properties dialog box in the Dressup area unselect all the options. This will turn off all hidden and center lines which should not be displayed in a pictorial view. 71. Your completed drawing should appear similar to Figure 19.46.

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Figure 19.46 The Completed Drawing of the Pump Gasket

EXERCISE 19.2 CREATING DIMENSIONED SECTION VIEWS In the examples below the creation of section views will be covered. Different examples will be given so that you will have exposure to creating different sectional views.

CREATING A ½ SECTION VIEWS In this example a ½ section view will be created and then deleted so that a full section can be constructed. 1. Make a copy of the Collar Jig model and place it into a subdirectory where your drawing file will be stored. This subdirectory will be the week subdirectory that this exercise was assigned. Load the ANSIB file. 2. From the Views toolbar select the Front View option (see Figure 19.47).

Figure 19.47 The Front View Option of the Views Toolbar 3. Change to the Collar Jig window and select the top view of the Collar Jig and place the front view as shown in Figure 19.48.

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Figure 19.48 Front View from the Collar Jig

4. From the Section toolbar select the Offset Section View option (see Figure 19.49). 5. Use the cursor to pick the vertical center above the part. Then pick on the part center. Next pick on the horizontal center to the right of the part. Finally, double click the last point to the right and under the part to end creating the cutting plane (see Figure 19.50). NOTE: you have to double click to end cutting plane line construction.

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Figure 19.49 The Offset Section Option Plane

Figure 19.50 Creating the Cutting View

6. By placing the cutting plane in front of the object you will get a correct half section view with one half of the part appearing as a half section and one half of the part appearing as the exterior view. 7. Notice there are dashed lines representing the hidden geometry in the section view. By convention there should not be any hidden surfaces shown on the half section. Move the cursor over the view frame and select it with the right mouse button and in the pop up window select Properties. The View Properties dialog box will appear. Under Dressup deselect the Hidden Lines option select OK and the hidden surfaces will not be displayed in the section view (see Figure 19.51).

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Figure 19.51 Turning off the Hidden Lines in the Section View 8. Again select the ½ section view frame with the right mouse button and in the Delete option to delete the ½ section view.

CREATING A FULL SECTION VIEW In this example a full sectional view will be created and the dimensions will be added to it. You will start with the front view of the Collar Jig that and create the full section view. 1. Select the Offset Section View command and place your cursor directly above the front view and click. Next place the cursor directly below the front view and double click. This locates the cutting plane line entirely through the object and results in a full section view to the right of the front view. 2. Correctly place the view by locating it with the mouse to the right of the front view and change the view properties of the section view to turn off the dashed lines that represent the hidden geometric features. 3. In the section view pick the centerlines and drag the ends so they are longer and thus easier to visualize.

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4. Place a bolt circle on the front view by using a geometry circle and changing the circles properties to a centerline (4) with line thickness of .13 (1). 5. Figure 19.52 shows the completed front and full section views of the Collar Jig .

Figure 19.52 The Completed Front and Full Sectional Views of the Center Support

ADDING DIMENSIONS TO THE FULL SECTION VIEW Remember that it is a very good practice to break down the geometry of a part before you begin the add dimensions to it. First, identify all of the positive geometry and apply dimensions to all of the positive geometry. In the Collar Jig, there are four positive geometries composed of three cylinders and one partial cone. There are five negative cylinders (holes) that also must be dimensioned. Then the holes must be located on the part. Positive cylinders and cone s should always dimensioned in the view where they appear as rectangles or triangles Thus, in this drawing all of the positive

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cylinders and cones will be dimensioned in the section view. They also require that the Φ diameter symbol appear before the dimensional value.

6. Select the Diameter Dimensions option from the Dimensioning toolbar and dimension the diameters of the cylinders and the cone in the section view (see Figure 19.53).

7. Select the Dimensions option from the Dimensioning toolbar and dimension the height dimensions of the cylinders and the cone in the section view (see Figure 19.54). NOTE: for the 2" height dimension of the cone before accepting the dimension you may have to right click on the dimension and select the Dimension Representation option and Force Horizontal Dimension in view to have the proper dimension appear. The positive geometry is now completely dimensioned.

Figure 19.53 Adding the Diameter Dimensions to the Section View of Collar Jig Geometry

Figure 19.54 Adding the Height Dimensions of the Positive the

8. Now dimension the negative geometry. First dimension the four .25 diameter holes where they appear as circles in the front view. Add the leader line and go into the dimension properties and add the "4X" to define the holes as being the same size (see Figure 19.55).

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Figure 19.55 Dimensions the Holes Counter-bored Hole

Applied Geometry for Engineering Design

Figure 19.56 Dimensioning the Four .25

9. Dimension the counter-bored hole. Typically counter-bored holes are dimensioned in the circular view because dimensioning to hidden features is a b ad practice, but because this is a section view the counter-bore d hole is visible in the rectangular view and the dimensions for the counter bored hole can be placed in the rectangular view (see Figure 19.56).

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Figure 19.57 Completing the Dimensioning of the Collar Jig 10. In the front view, the four .25 diameter holes are located by the bolt circle, thus it needs to be dimensioned. The completely dimensioned Collar Jig is shown in Figure 19.57. 11. Place an isometric pictorial view on the drawing at 1:2 scale and turn off all hidden and center lines, axes, and fillet representations in the isometric view. 12. Complete the title block. 13. Your completed Collar Jig drawing should appear very similar to Figure 19.58.

Figure 19.58 The Completed Collar Jig