Automating factories

victims of a system which finally tends to proletariatize the employees, especially white-collar workers. These phenomena are not new, of course. As Cooley points out, they could have been observed whenever a production has been rationalized. In connection with other precarious developments, however, (eg concentration of power in multinational corporations and the press, or the partial failure of the institutions responsible for society) they could lead to a crisis in which democracy itself is endangered. One chapter of deals with the socalled 'Lucas Corporate Plan' which attempts to overcome the above problems by letting the workers themselves take the initiative in creating and producing socially needed products. Although one has to be very careful not to generalize too quickly when looking at some examples, the basic ideas have to be agreed with. They are based on actual experience and the conclusions drawn are logical and not to be disapproved of. When estimating future developments, however, Mike Cooley does not

take into account the enormous reduction in the price of hardware. By using a 'megamini' which takes over much routine work, a job may become more comprehensive and the trend of decentralization brings back more responsibility, quite the opposite of Taylorism. Most remarkable about the book is the fact that, despite his negative experience, the author does not back a simple negation of the computer but recommends its wise application. Cooley emphasizes the task of all involved, in particular the unions and the employers, to achieve rules and ways of acting which enable the use of this technology within the realm of human rights without rousing antidemocratic tendencies. The activity of engineers and scientists is mainly a political one. Therefore a sterilized, neutral science is not possible in this context. The merit of this book is that it shakes up the specialist and makes him aware of his political responsibility.

Gert Lang-Lendorff

Automating factorms The ro/e of computers in manufacturing processes, G Halevi, Wiley Interscience, New York (1980) 502 pp, £24.50 This is an interesting book but the title is misleading. Much of its contents deal with the manufacturing process and the application of IBM computer programs in this wide area. The last 100 pages are like a technical sales brochure for Hat Technology. Hal, we are told, means 'all-embracing' in Hebrew. The author is director of the CAM/CAD Research and Development Centre, TeI-Aviv, Israel. He also teaches engineering design and CAD at the Israel Institute of Technology. The book first deals with the historical development of computers and how this has affected applications to manufacture. It sees the current stage as moving from a temporary aberration a company-wide proliferation of private minicomputers - to integrated manufacturing systems sharing a company database. In this, the computer is seen as an aid in the engineering design and

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process planning phases, but the decision maker in the production phase. Problems should be seen as parts of systems, and not as isolated topics, and data should be collected from the lowest possible level. Management and finance systems should be extensions of engineering and production systems. Product design, factors of safety, production methods, tolerances, classification systems, group technology, transfer lines and automatic small batch production are reviewed. Over one-third of the book is used to describe the separate steps of bill-ofmaterial expansion, manufacturing routing, production planning, requirements planning, inventory systems, capacity planning, shop floor control, and cost planning and control, drawing very largely on published IBM program information. The book then turns to generative process planning - the automatic determination by computer of how a component should be made, given only the design drawing information and a

list of the capabilities of all workshop facilities. Many of the difficulties are explored down to some detail like the strength of the part, chucking forces, practical limitations on the cutting process (however no mention of how to ensure that swarf is obtained in easily handled chips and not a tangled mass). Much space is devoted to selecting the best set of machines for the job and the best way to cut a part on the particular machines eventually found to be available. Although block diagrams and occasional printouts are given, there really is no new information and no detail to form a basis for anyone wishing to develop a system for their own organization. This is particularly so in the section on Hal Technology whe're the claims are all-embracing. The manufacturing process is treated as one interactive process from engineering design to product shipment. It does away with the unnecessary constraints imposed by treating each phase of the process by a separate program. It does away with the classification systems necessary for group technology, but groups families of parts for economical machining. Most CAD systems 'can "see" only points, lines, arcs and circles, conics, splines and interconnects. Hal requires the computer to "see" geometric shapes'. It is difficult to unwrap what Hal can do from what it wil/do. It appears that it can already cope with turned parts made on lathes (a common starting point because it is easier to link between twodimensional statements on shape and the actual 3D solids). However, it may be that true 3D shapes can be handled. The few examples of input shape descriptions do not help because input is in tabular form with numerical codes to indicate shapes and variable numbers of dimensions. There is no indication of what the codes and data mean. If complex 3D shapes can be described to Hal and result: in members of the same family of parts being found automatically, in planning how to make the parts optimally in a workshop loaded with small batch production jobs, in selection of the best date for entry into the job stream for each part and so on then the author is to be congratulated. It is claimed that, if components are made from bar stock, the system can deal optimally with the parts of bars. It can deal with pieces scrapped at any stage in manufacture and determine

computer-aided design

iiiiiiiiiiiiii which scrapped piece or pieces might be used for a new batch of different parts and plan the different ways these should be machined. It can decide whether it would be economical to break down an unrequited subassembly to use particular components as raw materials for other parts. The book will be useful to systems

engineers who want to ensure they do not overlook any part of the huge and complex process of manufacturing. Some of the chapters have a list of references up to about 1975 and there is an adequate index.

W H P Leslie

Finite elements made simple Introduction to finite element computations, E Hinton and D R Owen, Pineridge Press, UK (1979) 386 pp £16.

In their fourth book on finite elements, the authors consider in particular the computational aspects of this method and present it as a general concept for setting up computational models of various engineering problems. Thus, this book develops in a clear and systematic manner the mathematical formulations and also provides computer programs which actually permit the solution of practical problems. Clearly, the authors must restrict themselves in a book of approximately 400 pages to a relatively small number of finite-element types, but nevertheless a wide range of linear steady-state problems is considered. Besides the classical application of

volume 12 number 5 september 1980

finite elements to structural analysis, the book covers heat conduction, ground-water flow and irrotational flow of ideal fluids. Moreover, the volume contains numerous computational aids such as equation solution, mesh generation and node renumbering. Although most subjects presented can be found elsewhere, the unified treatment of different classes of problems in th~s book is worthy of study. Clear and consistent presentation in conjunction with the strong emphasis on practical applications make the book especially recommendable as a textbook for teaching finite-element methods to engineering students at undergraduate and graduate levels. In addition, due to its more advanced parts, this volume may also serve as a reference for the practising finiteelement analyst looking for quick and

relevant information on computational questions. On the other hand, one must not expect this book to give a complete introduction to finite-element theory; for a true understanding one should refer to the comprehensive and welldocumented bibliography provided. Programs listed seem to be better suited for students than for professional users, although verified tapes of codes are available from the publishers. The relatively primitive data input and line printer output restricts the application to engineers who are well acquainted not only with the method of computation but also with programming. Moreover, unfortunately, the instructions for preparing input are merely contained in an appendix to which the reference is unnecessarily complicated by an inconsistent differentiation between 'programs' and 'subroutines' in the subject index. Such minor shortcomings do, however, not affect the use of the book and can easily be removed in a revised edition. In conclusion, it may be stated that this book should be worth its price for every reader interested in finite element com~utations. D W Scharpf Rechen- und Entwicklungsinstitut fur EDV im Bauwesen - RIB e. V. Stuttgart, W Germany

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