CAD/CAM: Computer-Aided Design and Manufacturing
P T R Prentice Hall, Upper Saddle River, New Jersey 07458
Library of Congress Cataloging in Publication Data
Groover, Mikell P.,
CAD/CAM: computer-aided design and manufacturing.
Bibliography: p.
1. CAD/CAM systems. I. Zimmers, Emory W. II. Title.
III. Title: C.A.D./C.A.M.
TS155.6.G76 1984 670’.28’54 83-11132
ISBN 0-13-110130-7
Editorial/production supervision: Mary Carnis
Interior design: Barbara Cassel
Cover design: Edsal Enterprises
Manufacturing buyer: Gordon Osbourne
©1984 by P T R Prentice Hall
Prentice-Hall, Inc.
A Pearson Education Company
Upper Saddle River, NJ 07458
All rights reserved. No part of this book may be
reproduced, in any form or by any means,
without permission in writing from the publisher.
Printed in the United States of America
20 19 18 17 16 15 14
ISBN 0-13-110130-7
Prentice-Hall International (UK) Limited, London
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To
The CAD/CAM Program
at Lehigh University
Contents
1.2 The Product Cycle and CAD/CAM
part I COMPUTERS, THE FOUNDATION OF CAD/CAM
2.2 Central Processing Unit (CPU)
2.6 Computer Programming Languages
2.7 Operating the Computer System
3 Minicomputers, Microcomputers, and Programmable Controllers
4.3 The Application of Computers for Design
4.4 Creating the Manufacturing Data Base
4.5 Benefits of Computer-Aided Design
5 Hardware in Computer-Aided Design
5.5 Plotters and Other Output Devices
5.6 The Central Processing Unit
6 Computer Graphics Software and Data Base
6.2 The Software Configuration of a Graphics System
6.3 Functions of a Graphics Package
6.6 Data Base Structure and Content
6.7 Wire-Frame versus Solid Modeling
6.8 Other CAD Features and CAD/CAM Integration
part III NUMERICAL CONTROL, THE BEGINNINGS OF CAM
7 Conventional Numerical Control
7.2 Basic Components of an NC System
7.6 Applications of Numerical Control
7.7 Economics of Numerical Control
8.5 Computer-Assisted Part Programming
8.7 The MACRO Statement in APT
8.8 NC Programming with Interactive Graphics
Appendix: APT Word Definitions
9.2 Problems with Conventional NC
9.4 Computer Numerical Control
9.7 Adaptive Control Machining Systems
9.8 Trends and New Developments in NC
10.2 Robot Physical Configurations
10.6 Robot Programming Languages
10.8 Work Cell Control and Interlocks
11.1 General Considerations in Robot Applications
part V GROUP TECHNOLOGY AND PROCESS PLANNING
12.3 Parts Classification and Coding
12.4 Three Parts Classification and Coding Systems
12.5 Group Technology Machine Cells
12.6 Benefits of Group Technology
13 Computer-Aided Process Planning
13.2 Retrieval-Type Process Planning Systems
13.3 Generative Process Planning Systems
13.5 Machinability Data Systems
13.6 Computer-Generated Time Standards
part VI COMPUTER-INTEGRATED PRODUCTION MANAGEMENT SYSTEMS
14 Production Planning and Control
14.2 Traditional Production Planning and Control
14.3 Problems with Traditional Production Planning and Control
14.4 Computer-Integrated Production Management System
14.5 Cost Planning and Control
15 Inventory Management and MRP
15.3 Material Requirements Planning
15.9 MRP II: Manufacturing Resource Planning
16 Shop Floor Control and Computer Process Monitoring
16.2 Functions of Shop Floor Control
16.3 The Shop Floor Control System
16.5 The Factory Data Collection System
16.6 Computer Process Monitoring
17 Computer-Process Interfacing
17.2 Manufacturing Process Data
17.3 System Interpretation of Process Data
17.4 Interface Hardware Devices
17.5 Digital Input/Output Processing
17.6 Hierarchical Computer Structures and Networking
18.2 Structural Model of a Manufacturing Process
18.3 Process Control Strategies
18.4 Distributed Control versus Central Control
18.6 Supervisory Computer Control
19 Computer-Aided Quality Control
19.2 Terminology in Quality Control
19.4 Contact Inspection Methods
19.5 Noncontact Inspection Methods—Optical
19.6 Noncontact Inspection Methods—Nonoptical
19.8 Integration of CAQC with CAD/CAM
20 Computer-Integrated Manufacturing Systems
20.2 Types of Manufacturing Systems
20.3 Machine Tools and Related Equipment
20.6 Human Labor in the Manufacturing System
part VIII CAD/CAM IMPLEMENTATION
21 Implementing a CAD/CAM System
21.4 Evaluation of Alternative Systems
Preface
This book is intended to provide a comprehensive survey of the technical topics related to CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing). These topics include interactive computer graphics and CAD, numerical control, computer process control, robotics, group technology, computer-integrated production management, and flexible manufacturing systems. Many of these topics are covered in greater detail in other publications, and we have attempted to include a listing of important references at the end of each chapter. The unique feature of this book is that it brings all of these specialized topics together in one volume and attempts to demonstrate how they are all related. Our viewpoint is that these various topics represent a continuum of activity that must take place in a manufacturing firm rather than a collection of separate functions. With CAD/CAM, it should be possible to integrate and automate virtually every aspect of the design and production operations of the firm, thereby increasing the efficiency and the productivity of these operations.
The emphasis in the book is on computerized systems used in the discrete product manufacturing industries. It is designed for engineers, computer specialists, and managers who wish to learn about the technology, applications, and scope of CAD/CAM. The book should be suitable as a technical reference for the practicing professional who must make engineering and financial decisions about CAD/CAM projects. The technology of computer-aided design and manufacturing has undergone significant evolution during the last 10 to 15 years. This book should be useful in exposing engineers, managers, and computer scientists to the latest technology.
The book has also been designed as a textbook for college courses and industry continuing education courses in CAD/CAM. There is a good chance that we will use the book for these purposes at Lehigh University. More and more educators are recognizing the importance of this technology in their curricula. We anticipate that there will be a significant growth in the number of CAM and CAD/CAM courses offered by engineering schools during the present decade. It is our hope that this book will be an important contribution towards satisfying the need for a text in this growing area.
When I first started negotiations with Prentice-Hall in 1980 regarding a book on CAD/CAM, my thought was to develop a companion to my previous book entitled Automation, Production Systems, and Computer-Aided Manufacturing. The first book emphasizes automation and manufacturing, and it was my plan that the second book would emphasize computer-aided design and its integration with manufacturing using computer systems. It has turned out that the two books overlap each other to some extent. Readers of my first book might recognize in this second book a number of topics that are familiar. This overlap is not inappropriate since the two areas of automation and CAD/CAM do indeed include many common topics. My hope is that the two books will constitute a substantial and complementary set of volumes in the general field of computer-aided design, computer-integrated production systems, and factory automation.
In this CAD/CAM book, it seems appropriate that I acknowledge the contribution of Emory Zimmers, my coauthor, colleague, and contemporary in the Industrial Engineering Department at Lehigh. At the time I began to develop the outline for the book, it was apparent to me that the subject of CAD/CAM encompassed a very large and varied set of topics and technologies. If the full scope of CAD/CAM were to be covered in the desired detail, it seemed to me that the subject represented more material than could be adequately documented by a single author. Meanwhile, Emory had also been entertaining thoughts about writing a book on CAD/CAM, perhaps facing up to some of the same kinds of difficulties I was encountering. In the interest of producing a thorough, high-quality treatment in the field of CAD/CAM, Emory and I decided to collaborate on the project. His knowledge of the field would fill in the gaps of my knowledge, and vice versa. Specifically, Emory has made significant contributions in Chapters 2, 3, 4, 5, 6, 17, 21, and 22. The task of actually preparing the final manuscript for the book fell to me.
Acknowledgments
In a project as large as this book, the authors must usually rely on the assistance of other persons. In our case, contributions were made by many individuals and many companies, and we would like to hereby acknowledge their help. For their valuable assistance in either providing technical input and/or reviewing portions of the manuscript, we are indebted to the following individuals: John W. Adams, our colleague and statistician/mathematician at Lehigh; Frank Bibas, our former student now working in the robotics industry; Jim Buskirk, CAD/CAM specialist at Air Products and Chemicals, Inc.; Arthur Gould, our colleague and former department chairman at Lehigh; Jack Hughes, my good friend and sometimes coauthor from Air Products and Chemicals; Herb Ketcham, formerly of our Manufacturing Processes Laboratory at Lehigh; Marvin Kreithen of the Bridgeport Controls Division of Textron; Mark Lang of Lehigh’s Computer-Aided Design Laboratory and faculty member in Mechanical Engineering and Mechanics; Lance Leventhal, P-H author on computers; Ron Lovetri of the General Electric Company; Roger Nagel, Director of Lehigh’s Institute for Robotics; Glenn Offord, one of my master’s candidates at Lehigh and simultaneously an engineer for Western Electric Company; Louis Plebani, Jr., our colleague in the Industrial Engineering Department; Paul Quantz, who runs his own CAD/CAM consulting company; Ron Sherertz of the McDonnell-Douglas Corporation; Tom Shank of the General Electric Company; Theodore Terry, one of our colleagues in the mechanical engineering department; Mitchell Weiss of United States Robots; Bob Wolfe of the IBM Corporation; and Nello Zuech of Object Recognition Systems, Inc.
Much of the research and preparation of source materials for the book was accomplished by some of our students at Lehigh. Major contributions were made by Thomas Costello, Robert Gervis, Donna Harle, Robert Kimball, Carol Richardi (now Mrs. Glenn Riggin), and Jonathan Ripsom.
We are also indebted to a large number of companies in the CAD/CAM or related industries, which supplied us with a wealth of technical information, photographs (many of which appear as figures in the book), and other resource materials. These companies include Applicon, Bendix Corp. (Automation and Measurement Division), Bridgeport Machines Division of Textron, Inc., Cincinnati Milacron, Computervision Corp., Digital Equipment Corp., General Electric Company, Gerber Scientific Instrument Company, Heath Corp., IBM Corp., Kearney ' Trecker, McDonnell-Douglas Automation Corp., MDSI, MTM Association, Numeridex, Inc., Object Recognition Systems, Inc., Organization for Industrial Research, Inc., Prab Conveyors, Inc., Scans Associates, Inc., Threshold Technology, Unimation, Inc., and Warner ' Swasey, Inc.
A number of figures from my previous book, Automation, Production Systems, and Computer-Aided Manufacturing, were also used in the present book, and it is required that I acknowledge that these figures were reproduced from the previous book with the permission of Prentice-Hall. These figures are (figure numbers refer to the previous book): 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.10, 8.1, 8.4, 8.5, 8.6, 8.7, 8.8, 8.9, 8.10, 8.11, 8.12, 8.13, 8.14, 8.15, 9.1, 9.2, 9.3, 9.4, 9.6, 11.1, 11.2, 11.3, 11.4, 11.5, 11.6, 11.7, 11.8, 11.12, 11.14, 11.20, 12.2, 14.2, 15.1, 15.2, 15.3, 15.9, 16.3, 16.4, 17.1, 17.2, 17.4, 17.7, 17.8, 17.9, 18.1, 18.2, 18.3, 18.4, 18.5, 18.6, 18.7, 18.8, and 18.9. In addition, Table 16.2 from the automation book was reproduced with the permission of Prentice-Hall for the present book.
Finally, I would like to express my appreciation to Mrs. Marcia Mierzwa and her company, Information Processing Systems, for an excellent typing job on the manuscript for the book.
Dedication
The CAD/CAM Program at Lehigh University had its beginnings in the Industrial Engineering Department with some very modest project work on a single interactive computer graphics terminal in the early 1970’s. I remember one of those projects dealt with the graphics modelling of a cutting tool in a machining operation. In 1975, the Department formed the Computer-Aided Manufacturing (CAM) Laboratory, under the direction of Emory Zimmers. At that time, the growing importance of computers in manufacturing for numerical control, process monitoring, MRP, and other applications was clearly understood by those of us in industrial engineering whose specialty was related to manufacturing, but Emory had been largely responsible for the development of this area within our department. By around 1979, the Department of Mechanical Engineering and Mechanics had recognized the importance of computer graphics for design, and there were efforts to integrate computer graphics into the activities of that department. These efforts were led by their department chairman, Doug Abbott, and a new faculty member at that time, John Ochs. Ochs had done his doctoral work in acoustics at The Pennsylvania State University, and had used computer graphics as a tool in that research. Abbott, Zimmers, Ochs, and George Kane, Chairman of Industrial Engineering, formed a small group which included Mike Bolton of Lehigh’s Development Office to begin to develop the CAD/CAM area at the University. The decision to include Bolton in the group turned out to be a decision of significant merit. One of the principal activities of the group was to visit companies to solicit their participation in the University’s CAD/CAM Program. Bolton was very effective at making the right contacts and organizing these visits to industry. To merely say that many days were spent away from the University promoting the new program is an understatement of the amount of time and effort that was contributed by this group. The result of their efforts was a multimillion dollar development program that has provided some of the finest university CAD/CAM laboratory facilities in the country. In addition, and perhaps far more important, the CAD/CAM Program has also produced an awareness, an involvement, and an excitement about computer-aided design and manufacturing at Lehigh University that has motivated and benefited both our faculty and our students. At the time of this writing, the CAD/CAM activity has expanded well beyond industrial and mechanical engineering to include many other departments of the University. It is largely a result of the Lehigh CAD/CAM Program that this book was made possible, and it seems quite appropriate that our book be dedicated to the program.
Mikell P. Groover