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Springer Series in Advanced Manufacturing Series Editor Professor D.T. Pham Manufacturing Engineering Centre Cardiff University Queen’s Building Newport Road Cardiff CF24 3AA UK Other titles in this series Assembly Line Design B. Rekiek and A. Delchambre Advances in Design H.A. ElMaraghy and W.H. ElMaraghy (Eds.) Effective Resource Management in Manufacturing Systems: Optimization Algorithms in Production Planning M. Caramia and P. Dell’Olmo Condition Monitoring and Control for Intelligent Manufacturing L. Wang and R.X. Gao (Eds.) Optimal Production Planning for PCB Assembly W. Ho and P. Ji Trends in Supply Chain Design and Management: Technologies and Methodologies H. Jung, F.F. Chen and B. Jeong (Eds.) Process Planning and Scheduling for Distributed Manufacturing L. Wang and W. Shen (Eds.) Collaborative Product Design and Manufacturing Methodologies and Applications W.D. Li, S.K. Ong, A.Y.C. Nee and C. McMahon (Eds.) Decision Making in the Manufacturing Environment R. Venkata Rao Frontiers in Computing Technologies for Manufacturing Applications Y. Shimizu, Z. Zhang and R. Batres Reverse Engineering: An Industrial Perspective V. Raja and K.J. Fernandes (Eds.) Automated Nanohandling by Microrobots S. Fatikow A Distributed Coordination Approach to Reconfigurable Process Control N.N. Chokshi and D.C. McFarlane ERP Systems and Organisational Change B. Grabot, A. Mayère and I. Bazet (Eds.) Machining Dynamics K. Cheng (Ed.) ANEMONA V. Botti and A. Giret Suk-Hwan Suh • Seong-Kyoon Kang Dae-Hyuk Chung • Ian Stroud Theory and Design of CNC Systems 123 Suk-Hwan Suh, PhD School of Mechanical & Industrial Engineering POSTECH, San 31, Pohang, 790-784 Republic of Korea Seong-Kyoon Kang, PhD K&S International Patent and Law Firm 3F, Hanjin Bldg., 607-12 Yeoksam-dong, Kangnam-gu, Seoul, 135-907 Republic of Korea Dae-Hyuk Chung, PhD Doosan Infracore Co., Ltd. 601-3, Namsan-dong, Changwon-Si, Gyeongnam-Do Republic of Korea Ian Stroud, PhD École Polytechnique Fédérale de Lausanne (EPFL) STI-IGM-LICP, Station 9, 1015 Lausanne Switzerland ISBN 978-1-84800-335-4 e-ISBN 978-1-84800-336-1 DOI 10.1007/978-1-84800-336-1 Springer Series in Advanced Manufacturing ISSN 1860-5168 British Library Cataloguing in Publication Data Theory and design of CNC systems. - (Springer series in advanced manufacturing) 1. Machine-tools - Numerical control 2. Machine-tools - Numerical control - Programming I. Suh, Suk-Hwan 621.9'023'0285 ISBN-13: 9781848003354 Library of Congress Control Number: 2008928587 © 2008 Springer-Verlag London Limited Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitte d under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency. Enquiries concerning reproduction outside those terms should be sent to the publishers. The use of registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant laws and regulations and therefore free for general use. The publisher makes no representation, express or implied, with regard to the accuracy of the informatio n contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. Cover design: eStudio Calamar S.L., Girona, Spain Printed on acid-free paper 9 8 7 6 5 4 3 2 1 springer.com This book is dedicated to: Eun-Sook Choi, Hyeon-Jeong Lee, Hye-Jung Kim, and Hildegarde Nagy-Stroud and to the rest of our families for their endurance of this headlong task. Preface CNC controllers, working as a brain for manufacturing automation, are high value- added products accounting for over 30% of the price of machine tools. CNC technol- ogy is generally considered as a measure of the level of manufacturing technology of a nation, and is currently led by major advanced countries such as USA, Japan, and Germany. CNC technology, which cannot be developed with one single technology but needs to integrate computer technology, hardware technology, machining tech- nology, and so on, is often referred to as “The Flower of Industrial Technology”, and requires a strategic long-term support, mostly on a governmental level. Despite its significant role, textbooks on CNC controllers are quite rare world- wide, with a few published in the 1970s and some later. However, the earlier ones mostly deal with conventionaltechnologies, while the later ones deal with fragmental contents, mostly focusing on part programming and machine operation. This book is written by several authors in collaboration who have long experience in CNC de- velopment, education, and research, and is designed as a highly focused textbook to provide knowledge on the principles and development technologies of CNC con- trollers. Therefore, this book can be used as a main textbook for courses related to CNC in such departments as mechanical engineering, precision engineering and con- trol engineering, and as a guide for those working on CNC development in industry. If highly descriptive portions are taken out, it can also be used as lecture material in technical colleges. The framework of industrial CNC controllers has been established by integrat- ing the structure and element technologies of CNC controllers under research and development by the authors in their respective field of industry and academia over the years. Furthermore, this book intends to encourage the spirit of development by introducing actual realization cases. This book is composed of two parts with a total of 11 chapters: Part I is composed of Chapters 1–6 on the principle and design of CNC, and Part II is composed of an open-architectural soft CNC system. Specifically, Chapter 1 provides general con- cepts and mechanisms of numerically controlled machines, while Chapters 2 through 5 cover the element technologies of NCK in charge of controlling the transfer axis, including interpreter, interpolator, control of acceleration and deceleration, and po- vii viii Preface sition control system. In Chapter 6, NCK development cases are described together with source code. Therefore, those who are interested in motion controllers can de- velop independent control devices by referring to the contents of Chapters 2 through 6. Part II describes the open-architectural soft CNC system, including the principles of major modules of numerically controlled machines, except the NCK (dealt with in Part 1), and the system design process for the composition of the overall system from the perspective of open-architectural soft CNC systems. Specifically, Chapter 7 ex- plains the PLC, controlling most mechanical motions except the transfer axis, while Chapter 8 presents the principles of the Man-Machine Interface (MMI) and the ma- jor modules for the development of conversational programming methods. Real-time operation concepts and methods necessary for designing real-time controllers are de- scribed in Chapter 9, Chapter 10 describes the architecture design of CNC systems based on personal computers. This is discussed from the perspective of soft CNC, including several approaches to the architecture of open-style CNC system with free external interfaces, and the design process of those approaches. The concept and pri- mary elements of STEP-NC are introduced in Chapter 11, which has recently come under the spotlight as a method of realizing intelligent CNC machines. Therefore, those who are interested in designing and realizing open-style soft CNC devices can refer to the topics covered in Chapters 7 through 11 to materialize intelligent open- style NC devices. As authors of this book, we recommend that instructors have their students ac- tually code the NCK technologies (Chapters 2 through 5), which are the core ele- ments, and finish a computer simulation system, one similar to the development case covered in Chapter 6, and verify the performance. One step further, if the interface board (encoder signal and PLC signal processing) and the XY-table can actually be connected by the students, the effect of learning can be doubled. Those students who want to learn the general technologies related with CNC sys- tems can achieve their goals by studying the PLC, conversational programming sys- tem, particularly actual cases of system programming methods to realize soft CNC, as covered in Part 2, Chapters 7 through 11. To complete this book it took over three years to collect and organize all sorts of material accumulated over a period of many years, including technical papers and patent data materials. However, we feel there are many shortcomings. Some of the excuses we can offer could include the fact that CNC technology has been developed by industry itself and that each element technology derives from a completely dif- ferent domain of knowledge. Therefore, for integrating them under the umbrella of CNC for academic purposes, many problems are posed such as un- or mis-defined technical terminologies and lack of systematic knowledge bases. However, despite this, the authors decided to publish this book in the hope that it will contribute to the advancement of CNC technology both at home and abroad, in consideration of the sheer reality that no proper textbooks are available for education or training in CNC technology. With lots of input from the readers, we hope this book can improve its contents in the future. Preface ix This book was originally published in Korean and has now been translated into English. We would like to take this opportunity to express our appreciation to Ms. Eunsook Choi, who encouraged preparation of the English version of the original Korean text book, Mr. Suho Jung and students of the Center for ubiquitous manu- facturing at POSTECH for help in the editing, and Springer who willingly accepted publication of it. We would also like to express our appreciation to Dae-Jung Seong of Doosan Infracore in charge of CNC development for providing contemporary industrial per- spectives. Postech, Suk-Hwan Suh, Seong-Kyoon Kang, March 2008 Dae-Hyuk Chung, Ian Stroud Contents Abbreviations xvii Part I Principles and NCK Design of CNC Systems 1 Introduction to NC Systems . 3 1.1 Introduction . . . 3 1.2 TheHistoryofNCandNCMachineTools . 6 1.3 CNC Driving System Components . . . . 8 1.3.1 DrivingMotorandSensor . 9 1.3.2 LinearMovementGuide 15 1.3.3 Coupling . 16 1.4 CNCControlLoop . 17 1.4.1 Semi-closedLoop 18 1.4.2 ClosedLoop 18 1.4.3 HybridLoop 19 1.4.4 OpenLoop . 19 1.5 The Components of the CNC system . . 19 1.5.1 MMIFunction . 22 1.5.2 NCKFunction . 23 1.5.3 PLCFunction . 25 1.5.4 Real-timeControlSystem . 28 1.6 TheProgressDirectionoftheCNCSystem . 29 1.7 Summary . 31 2 Interpreter 33 2.1 Introduction . . . 33 2.2 PartProgram 34 2.2.1 ProgramStructure . 35 2.2.2 Main Programs and Subprograms. . . 39 2.3 MainCNCSystemFunctions 40 2.3.1 CoordinateSystems 40 xi . composed of two parts with a total of 11 chapters: Part I is composed of Chapters 1–6 on the principle and design of CNC, and Part II is composed of an open-architectural. Stroud Theory and Design of CNC Systems 123 Suk-Hwan Suh, PhD School of Mechanical & Industrial Engineering POSTECH, San 31, Pohang, 790-784 Republic of