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Advances in Factories of the Future, CIM and Robotics PDF

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MANUFACTURING RESEARCH AND TECHNOLOGY Volume 1. Flexible Manufacturing: Recent developments in FMS, Robotics CAD/CAM, CIM (edited by A. Raouf and S. I. Ahmad) Volume 2. Computer-Aided Design, Selection and Evaluation of Robots (B. O. Nnaji) Volume 3. Modelling and Design of Flexible Manufacturing Systems (edited by A. Kusiak) Volume 4. Flexible Manufacturing: Integrating technological and social innovation (R T. Bolwijn, J. Boorsma, Q. H. van Breukelen, S. Brinkman and T. Kumpe) Volume 5. Proceedings of the Second ORSA/TIMS Conference on Flexible Manufacturing Systems: Operations research models and applications (edited by K. E. Stecke and R. Suri) Volume 6. Recent Developments in Production Research (edited by A. Mital) Volume 7A. Intelligent Manufacturing Systems I (edited by V. R. Milacic) Volume 7B. Intelligent Manufacturing Systems II (edited by V. R. Milacic) Volume 8. Proceedings of the Third ORSA/TIMS Conference on Flexible Manufacturing Systems: Operations research models and applications (edited by K. E. Stecke and R. Suri) Volume 9. Justification Methods for Computer Integrated Manufacturing Systems: Planning, design justification, and costing (edited by H. R. Parsaei, T. L. Ward and W. Karwowski) Volume 10. Manufacturing Planning and Control -A Reference Model (F. P. M.Biemans) Volume 11. Production Control-A Structural and Design Oriented Approach (J.W. M. Bertrand, J. C. Wortmann and J. Wijngaard) Volume 12. Just-in-Time Manufacturing Systems-Operational planning and control issues (edited by A.Satir) Volume 13. Modelling Product Structures by Generic Bills-of-Materials (E. A. van Veen) Volume 14. EconomicandFinancial Justification of Advanced Manufacturing Technologies (edited by H.R. Parsaei, T.R. Hanley and W.G. Sullivan) Volume 15. Integrated Discrete Production Control: Analysis and Synthesis- A View based on GRAI-Nets (L Pun) Volume 16. Advances in Factories of the Future, CIM and Robotics (edited by M. Cotsaftis and F. Vernadat) MANUFACTURING RESEARCH AND TECHNOLOGY 16 Advances in Factories of the Future, CIM and Robotics Edited by Michel Cotsaftis UR/CENFAR, Fontenay-aux~Roses, France FrangoisVernadat INRIA-Lorraine, Metz, France ELSEVIER Amsterdam - London - New York - Tokyo 1993 ELSEVIER SCIENCE PUBLISHERS B.V. Sara Burgerhartstraat25 P.O. Box 211,1000 AE Amsterdam, The Netherlands ISBN: 0 444 89856 5 © 1993 Elsevier Science Publishers B.V. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without the prior written permission of the publisher, Elsevier Science Publishers B.V, Copyright & Permissions Department, P.O. Box 521,1000 AM Amsterdam, The Netherlands. Special regulations for readers in the U.S.A. - This publication has been registered with the Copyright Clearance Center Inc. (CCC), Salem, Massachusetts. Information can be obtained from the CCC about conditions under which photocopies of parts of this publication may be made in the U.S.A. All other copyright questions, including photocopying outside of the U.S.A., should be referred to the copyright owner, Elsevier Science Publishers B.V., unless otherwise specified. No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. pp. 167-176,199-208,397-406: Copyright not transferred. This book is printed on acid-free paper. Printed in The Netherlands V FOREWORD Productivity enhancement is a major concern for all manufacturing enterprises. Productivity enhancement can be achieved in many ways and many facets of this problem have been investigated over the last decades (design automation, CAD/CAM integration, flexible manufacturing, robotized activities, cellular manufacturing, JIT, new management strategies, CIM and enterprise integration, intelligent systems and more recently concurrent engineering to name a few). A number of methods, tools and technologies have emerged to efficiently increase productivity and rationalize management of manufacturing enterprises. This does not mean that complete, packaged, solutions are available or even known in most cases. Furthermore, a global understanding of the productivity enhancement problem in the context of the current economic situation, and then for the ones to come, still needs to be assessed. The aim of the Eighth International Conference on CAD/CAM, Robotics and Factories of the Future (CARs & FOF 92) held in Metz, France on August 17-19, 1992, was to bring together experts coming from all over the world, both from academia and industry, to share their experience and contribute to advances of the many facets of productivity enhancement in manufacturing enterprises. CARs & FOF' 92 was the eighth event of a series of conferences sponsored by ISPE (the International Society for Productivity Enhancement). This post-conference book puts together some of the most signigicant papers presented at the conference in selected technical areas as a contribution to productivity enhancement in manufacturing enterprises. These technical areas can be grouped into four major sections: Factories of the future, Techniques and tools for automated manufacturing, Robotics, and Industrial applications. Factories of the future The impact of new technologies on modern or future production systems has to be assessed, and the socio-economical consequences as well as organisational changes have to be analysed. New ways of managing project development as well as team work will emerge. Furthermore, enterprise integration, for which enterprise modelling is one of the central issues, still needs to be the focus of further research. This section groups papers dealing with themes and vision on factories of the future, new management approaches, manufacturing system integration and manufacturing information systems. Techniques and tools for automated manufacturing This large section collects papers on technical issues dealing with product design and product engineering, as well as manufacturing system design, analysis and evaluation. The papers have been organized into seven categories: knowledge-based systems for manufacturing system simulation, CAED (Computer-Aided Engineering and Design), metal cutting and assembly processes, manufacturing cell layout, scheduling and multi-level control of FMS, FMS analysis with Petri nets, and fault diagnosis and maintenance. The first category contains two papers on the use of knowledge-based systems for advanced simulation of manufacturing processes. VI The second category focuses more on product engineering aspects with two contributions on finite element analysis, one on product configuration management and one on a CAD/CAE tool applied to circuit-breaker design. The third category addresses decision-making in metal cutting and specific problems in automated assembly. The fourth category is devoted to manufacturing cell layout using the cellular approach and covers cell design by machine grouping, machine layout inside a cell (considering materials handling systems), and workshop layout using the neural network approach. The fifth category covers scheduling problems and hierarchical control of FMS, while the sixth category concentrates on the use of Petri nets to model, analyse and control FMS. The seventh category contains two papers related to system failure and maintenance of manufacturing systems. Robotics Operating technical systems such as robots in high range of parameters, as required by productivity constraints in factories for tasks performance in the context of current economic competition, introduces, among other things, new problems in their control, under the two following main aspects: one is related to appropriate representation of physical phenomena, another one is in the definition and work out of a control structure to be applied to the system so that it behaves "intelligently" enough for tasks performance. With this respect, recent slowdown of robot use in factories at the end of the eighties has shown limit in totally programmed units, and a need for more decisional flexibility at robot level for better adaptation to task assignment in unstructured or partially structured environments. Advantage has therefore been taken from the CARs &FOF 92 Conference to gather some of the most interesting advances in robotics in representation and control areas showing possible orientation toward the goal of providing more flexibility to the robot unit. The selected contributions are mainly covering the following topics: the representation of the system, the generation of its trajectory, and its control. In the first category, there is only one paper on an attractive theoretical representation of flexible structures. It proposes nice aspects of them and is adequate for numerical workout. In the second category, five papers have been selected, and they are mainly proposing solutions to acceptable and precise enough system trajectories, including the case of redundant structure, which seems to be an interesting alternative for technical cases. Mobile robots are also considered. Finally, in the third category, the still very important control problem puts together the last five contributions. It can be seen that they are essentially proposing new extensions of control toward larger robustness and larger adaptivity, which are both important key factors for future robotic structures. These contributions are also seen to have a definite orientation toward passivity property, here appearing as a strong and useful one. Although the various texts are by far not covering all aspects of the difficult and not yet solved problem of the setting of new highly performing robotic units, they are however clearly Vll showing a pattern of valuable and interesting approaches to the fascinating problem of designing a new generation of robots with high enough performance capabilities to be used in industrial context. Industrial applications A few papers on industrial applications have been added to the book to illustrate or complement previous sections. Papers can be found on such issues as: simulation and control or scheduling of manufacturing systems, process control, process instrumentation, preventive maintenance and assembly systems in areas such as steel industry, electrical industry and discrete parts manufacturing. M. COTSAFTIS and F. VERNADAT Metz, November 1992 Advances in Factories of the Future, CIM and Robotics M. Cotsaftis and F. Vernadat (Editors) © 1993 Elsevier Science Publishers B.V. All rights reserved. 3 Future Factories and Today's Organizations P. Robert Duimeringa, Frank Safayenia and Lyn Purdyb department of Management Sciences, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada bCentre for Administrative and Information Studies, University of Western Ontario, London, Ontario, N6A 5C2, Canada Abstract This paper will draw from our experience during the past five years with organizations which are trying to improve their manufacturing activities using a variety of techniques and technologies. The paper will raise issues about how we are currently thinking about manufacturing systems, the kinds of solutions we consider as potentially feasible, and the difficulties organizations encounter implementing these solutions. Specifically, the paper will examine the Just-in-Time (JIT) and Computer Integrated Manufacturing (CIM) approaches as integrated manufacturing systems, and consider the impact of these systems on the manufacturing organizations in which they are implemented. A conceptual framework of the JIT system, developed through past research, will be utilized along with other organizational theory to point out shortcomings in some of the implicit assumptions underlying the CIM approach, and to examine how truly integrated manufacturing systems can be designed, regardless of the techniques or technologies chosen. The argument will be advanced that the only way for future factories to be effective is by 1) considering manufacturing activities in the context of the overall organizational system, 2) redesigning organizations to accommodate manufacturing activities, and 3) rethinking the ways advanced manufacturing technologies can be utilized, not only in terms of their theoretical potential, but also in terms of the concrete realities of organizations. 1. INTRODUCTION In response to increasing international competitive pressures over the past decade, Western manufacturers have focused a great deal of attention on attempts to improve manufacturing activities through the adoption of new techniques and technologies. Among the new strategies being pursued, two dominant themes have emerged. The first is the Just-in-Time (JIT) manufacturing system, originally developed by the Toyota Motor Company of Japan, which includes a range of techniques aimed at simplification and waste reduction within the manufacturing system. The second is the Computer Integrated Manufacturing (CIM) approach, in which computer based information systems are utilized to link islands of automation, islands of information, and flexible technologies throughout the manufacturing operation. While the development and adoption by industry of these two strategies has occurred more or less independently and their compatibility is not well understood, both approaches are generally assumed to be advantageous to manufacturing organizations attempting to improve the competitiveness of their operations. For example, both systems claim to contribute to increased productivity by improving organizational integration, product quality, as well as manufacturing 4 flexibility and responsiveness. As such, future factories can be expected to combine some of the characteristics of both the JIT and CIM approaches. Empirically, however, what is known about the success of the two manufacturing approaches within industry is rather limited. As a total system, JIT has been shown by Toyota and other Japanese firms to be an effective strategy for improving productivity when implemented appropriately [eg. 10]. CIM on the other hand is still largely an unproven manufacturing approach with very few well documented case studies. Most of the literature describing CIM considers the system from a purely hypothetical perspective, and tends to consist mainly of predictions made about the success of the system based on the "theoretical potential" of CIM technology [eg. 4,7]. It is also worth noting that the degree to which either of the two strategies has been successfully implemented by Western manufacturers has been very limited. The limited success is often related to the assumptions about the organizational context in which these systems are implemented. For example, organizations often assume that they can implement JIT without modifying their organizational structure [6,13]. Similarly, with respect to CIM, incorrect assumptions related to human resources have been shown to result in sub-optimal performance of advanced technological systems [12]. The objective of this paper is to examine JIT and CIM as integrated manufacturing systems, and to consider the relative impact of these systems on the manufacturing organizations in which they are implemented. The paper will utilize a conceptual framework of the JIT system which has been developed through our past research, as well as other organizational theory, in order to point out critical shortcomings in some of the assumptions underlying the CIM approach and highlight some of the organizational issues which must be addressed for future factories to effectively utilize either JIT or CIM. 2. THEORETICAL FRAMEWORK 2.1. Total Cycle Time Reduction as a Common Goal in JIT and CIM Before considering the differences between JIT and CIM, it is worth noting one important similarity between the two systems. In particular, underlying both systems is the idea of "total cycle time reduction" as a key factor leading to improved manufacturing productivity. In JIT, a major (but by no means exclusive) focus of the system is on production throughput time reduction, achieved primarily through the reduction or elimination of inventory buffers throughout the manufacturing system. By implementing a range of JIT techniques, designed to let manufacturers operate with low inventory levels, production throughput times can be significantly reduced. In the CIM system, the concept of cycle time reduction is enlarged to include not only production cycle times, but also administrative cycle times, such as order processing cycle times and product development cycle times. By utilizing computer based information technologies which allow for instantaneous information transmission and data sharing, as well as flexible manufacturing technologies capable of producing in very small batches, it is argued that the CIM system can dramatically reduce both production and administrative cycle times simultaneously [7]. Theoretically, the relationship between cycle time and manufacturing productivity has recently been identified in the literature [8,14,15]. For example, Wacker [15] has formally shown that when reduced throughput time is taken as the overriding goal of a manufacturing system, other goals which have been traditionally assumed to be contradictory, cease to behave as such. Consequently, underlying both JIT and CIM is a common (and apparently valid) assumption that reducing cycle times can lead to improved productivity levels. 2.2. Implications of Reduced Cycle Time in the JIT System Some of the differences between JIT and CIM arise when one considers how the two systems address the question of reduced cycle times. Through our past research on JIT, we have developed a conceptual framework for understanding the JIT system and its implications for manufacturing organizations [5,6,13], based on the theory of cybernetic systems [1,2]. In 5 particular, the framework considers the impact of reductions in the level of inventory (ie. reduced cycle times) on the functioning and structure of manufacturing organizations. Theoretically, the role of inventory within a manufacturing system is viewed as a buffer which handles variability between interrelated manufacturing processes. The significance of inventory as a buffer lies in the fact that it decouples interrelated processes from one another, thereby preventing the variability of one process from having an immediate impact on another. Some examples might be as follows. Suppliers shipping an incorrect part, machines breaking down in production, and unexpected worker absenteeism can all be considered as variabilities in the production system, which can be absorbed by high levels of inventory such that production operations can continue without disruptions. For instance, there may be enough stock on hand to give the supplier time to send another shipment, to allow time to repair a malfunctioning machine, or for other workers to continue production even if one worker does not show up for work. Other sources of manufacturing variability might include organizational functions, such as design engineering or marketing. For example, product designs which incorporate a large number of non-standard components or frequent changes in the production schedule generated by the marketing department both constitute sources of variability from the point of view of manufacturing, which have traditionally been absorbed by high levels of inventory. Since the presence of inventory tends to minimize the impact of variability in the system, significant inventory reductions will decrease the time it takes for variability in one process or organizational function to have an impact on another by increasing the coupling, or degree of interdependence, between interrelated activities. In the context of the preceding examples, small amounts of inventory mean that the wrong part from a supplier, machine breakdowns, absent workers, non-standard design components, or sudden schedule changes will rapidly disrupt the manufacturing system. If the organization cannot use inventory for handling variability in a low cycle time manufacturing system, alternative courses of action must be taken to avoid disruptions. Essentially, two possible options are available. The first involves reducing variability at the source, and the second has to do with increasing variability handling mechanisms at the point of impact within production. Considering the above examples, variability reduction might include such activities as pressuring suppliers to ensure consistently correct shipments, preventive maintenance to reduce the likelihood of machine breakdowns, modifying the employee reward structure to discourage absenteeism, ensuring the use of standardized components in design, and levelling production schedules to filter out market fluctuations. Strategies aimed at increasing variability handling within the system might involve developing emergency shipping procedures to handle late supplier shipments, having back-up equipment available in case of machine breakdowns, developing a multi-functional work force such that workers can be reassigned in the case of absenteeism, and increasing the flexibility of manufacturing processes to cope with high levels of component variety or unstable production schedules. To summarize these concepts, if organizations are to operate with short cycle times by lowering levels of inventory, increased interdependence implies that the level of variability impacting the production system must either be reduced at the source, or handled effectively at the point of impact by increasing variability handling capability within production. 2.3. Cycle Times and Manufacturing System Integration Conceptually, there is a direct relationship between the preceding concepts and the idea of an integrated manufacturing system. One may talk about a truly integrated manufacturing system as one in which different interrelated organizational tasks and activities are carried out in concert with one another. That is, an integrated manufacturing system is one in which variability reduction and variability handling are performed effectively. Organizational integration can therefore be considered in terms of its relationship to manufacturing and administrative cycle times. An organization which, through effective variability reduction and handling, is able to generate its required production or administrative outputs in very short cycle 6 times could be described as being well integrated. An organization which requires long cycle times to generate its required outputs could be described as being poorly integrated. An integrated manufacturing system cannot be achieved without addressing the question of how the production activities are affected by the other functional activities being performed elsewhere within the organization. For appropriate variability reduction and variability handling to take place, effective coordination of these interrelated activities becomes absolutely necessary. Our research on the JIT system, for example, has shown that in successful JIT organizations, lower production cycle times correlated not only with a broader range of organizational activities aimed at reducing variability and increasing variability handling mechanisms, but also with higher degrees of cross-functional communication and coordination, and a tendency to structure the organization along product rather than functional lines [5,6]. The relationship between lower cycle times and organizational changes is related to the idea of increased interdependence. As cycle times are reduced, interdependence increases within the organization along a particular orientation, namely the direction defined by the information and material flow lines associated with particular products. Consequently, there is a need for increased communication and coordination along this direction, creating a strong pressure to modify the organizational structure along product lines rather than functional lines. Hence, system integration is achieved in successful JIT organizations through the basic redesign of the organizational structure as well as a redesign of interrelated processes and functional activities. The main issue in designing low cycle time manufacturing systems, therefore, involves addressing the question of how variability is reduced or handled within the organizational system. Whether this is accomplished using technology, people, or any other method is not the crucial issue. What is important is the manner in which interrelated activities are designed, organized and coordinated throughout the organizational structure in order to achieve the goal of reduced cycle times. The focus of the remainder of this paper will be to examine the CIM system in this context by considering the approaches used by CIM to achieve organizational integration and handle system variability. 3. CIM AS AN INTEGRATED MANUFACTURING STRATEGY The preceding discussion has argued that integration within a manufacturing organization involves addressing the question of how variability is reduced or handled throughout the organizational system.. In highly integrated manufacturing organizations, characterized by low manufacturing and administrative cycle times, effective variability reduction and handling necessitates changes in how interrelated processes and functional activities are coordinated and organized. That is, manufacturing system integration is viewed primarily as an issue of organizational system design. When the CIM approach is considered in the context of this conceptual framework, however, it becomes apparent that the CIM system implies a different approach for achieving manufacturing system integration. Essentially, it is argued in the literature, that the CIM system brings about organizational integration (ie. reduced administrative cycle times) by automating the flow of information between interrelated processes and organizational functions (islands of automation) using advanced information technologies [4,7]. In addition, cycle times are reduced within production through the use of flexible manufacturing technologies (such as robotics, FMS, automated guided vehicles, automated storage and retrieval systems, etc.), which are capable of quickly processing a broad range of products in small batches. That is, the main approach used in the CIM system for dealing with organizational variability is to increase the level of flexibility, in order to handle variability at the point of impact within the production operation. As such, both integration and variability handling within the CIM system are essentially assumed to be purely technological issues, rather than organizational issues. The following sections of this paper will examine these assumptions in detail, by raising issues related to the ideas of integration and flexibility as they pertain to the CIM system. The technological approach of CIM will be considered in the context of today's organizational

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Most books are stored in the elastic cloud where traffic is expensive. For this reason, we have a limit on daily download.