Showing papers on "Computer-integrated manufacturing published in 1986"

Accounting Lag: The Obsolescence of Cost Accounting Systems

Abstract: Contemporary changes in the organization and technology of manufacturing operations have caused the traditional, direct-labor focused, cost accounting system to be a less useful summary of a company's manufacturing operations. A select set of manufacturing firms, leaders in both high-technology growth industries and highly efficient innovative producers in mature industries, were visited in order to learn what changes were being made in their accounting, measurement, and control systems to support the current emphasis on new product and manufacturing technologies. While each firm was making significant changes in its manufacturing processes, comparable changes were not occurring in its accounting and control systems—except, perhaps, on a preliminary and experimental basis. This article concludes with some conjectures as to why the pace of innovation in management accounting systems is lagging behind the rate of change in the organization and technology of manufacturing operations.

Modeling manufacturing grips and correlations with the design of robotic hands

Abstract: This paper represents the first part of an effort to codify the knowledge required for manipulation tasks in a small-batch manufacturing cell. The motivation for this work is to pave the way for robots that can independently determine how to grasp and manipulate parts in a limited environment and to facilitate the design of advanced, but cost-effective manufacturing hands. We begin with an examination of grasps used by humans working with tools and metal parts. The grips are compared in terms of power, contact area, friction, damping and tactile sensitivity. The comparison leads to a grip taxonomy in which grasps are mapped against task-related quantities (such as power) and object-related quantities (such as slenderness). The examinations of the task requirements and grasps suggest a number of general principles for the design and control of manufacturing hands.

A control perspective on recent trends in manufacturing systems

Abstract: Many notions from control theory are relevant here, although their specific realization is quite different from more traditional application areas. The standard control theory techniques do not apply: we have not yet seen a manufacturing system that can be usefully represented by a linear system with quadratic objectives. This is not surprising; standard techniques have been developed for what have been standard problems. Manufacturing systems can be an important area for the future of control; new standard techniques will be developed. Some central issues in manufacturing systems include complexig, hierarchy, discipline, capacir):, uncertaing, and feedback. Important notions of control theory include state and control variables, the objective function, the dynamics or plant model, and constraints. It would be premature to try to identify these with all the issues outlined in this paper; it would even go against the purpose of the paper, which is to stimulate such modeling activity. In this section, we describe the relevance of these notions to the manufacturing context for readers whose primary background is in control and systems.

Flexibility in manufacturing systems

Abstract: Considerable interest is now being shown in the concept of flexible manufacturing systems. This paper reviews the early experience of a number of UK users and examines the range of choice now opening up for firms engaged in batch manufacturing operations. Although the potential benefits of flexible manufacturing (such as reduced lead times or inventory levels) are significant, achieving these in practice depends on successfully resolving a number of problem issues. In particular, the question of integration—both technological (hardware/software) and organisational—needs to be addressed. The paper discusses progress made in the firms studied in dealing with these issues and identifies a number of dimensions along which other organisations considering the implementation of flexible manufacturing systems will need to adapt.

Design Rules for a Cim System

Abstract: 1. Introduction. 2. Development of CIM Design Rules. 3. Computer Aided Design (CAD). 4. Computer Aided Production Engineering (CAPE). 5. Computer Aided Production Planning (CAPP). 6. Computer Aided Manufacture (CAM) / Computer Aided Storage and Transportation (CAST). 7. Computer Aided Manufacture (CAM) / Computer Aided Transportation and Storage (CAST). Sub-topics. 8. General Interface Rules. 9. Development of Strategies. 10. Data Strategy. 11. Processing: State of the Art. 12. Processing Strategy. 13. Communication: State of the Art. 14. Communication Strategy. 15. Sensor Systems and Computer Integrated Manufacturing. 16. Graphics Systems and Computer Integrated Manufacturing. Appendices: Flowcharting Conventions. Selection Processes. Computer Aided Design of Solid Objects. Sensor Applications. CIM in the Small Firm.

Annotated Bibliography on Justification of Computer-Integrated Manufacturing Systems

Abstract: This is an extensive, but not exhaustive, bibliography for persons interested in the Justification (economic and/or non-economic) of the various aspects normally associated with computer-integrated manufacturing (CIM) systems. Moat works cited Include a brief annotated comment regarding subject inclusions and perhaps perceived strengths- For the 100 plus citations, fifty-two are categorized as being generally subjective overview/guidelines, and thirty-five are categorized as including quantitative techniques/analysis methodologies for Justification of CIM systems or components of such systems.

Petri net-based object-oriented modelling of distributed systems

Abstract: This paper presents an object-oriented approach for building distributed systems. An example taken from the field of computer integrated manufacturing systems is taken as a guideline. According to this approach a system is built up through three steps: control and synchronization aspects for each class of objects are treated first using PROT nets, which are a high-level extension to Petri nets; then data are introduced specifying the internal states of the objects as well as the messages they send each other; finally the connections between the objects are introduced by means of a data flow diagram between classes. The implementation uses ADA as the target language, exploiting its tasking and structuring mechanisms. The flexibility of the approach and the possibility of using a knowledge-based user interface promote rapid prototyping and reusability.

Building "Expert systems" when no experts exist

Abstract: The new technology of Flexible Manufacturing Systems (FMS) presents a variety of problems having to do with planning, scheduling, and control of manufacturing. These problems can be very complex, and so can require computer-based decision support for solutions. One element of such support could be artificial intelligence, of the form represented by expert systems. But there is a paradox: the more complex and novel the manufacturing problems are, the less likely it is that any humans who are expert about them even exist. This paper discusses what can be done, within the spirit if not the letter, of the AI expert-system concept, given this kind of situation.

Cae for the manufacturing engineer: the role of process simulation in concurrent engineering

Abstract: As America refocuses its attention on the factory, design and manufacturing engineers must work together closely to design the appropriate products, and matching production process in a team effort. By building off the designer's CAE tools that predict product performance, the manufacturing engineer is today able to simulate the proposed production process. Process simulations for the following manufacturing processes are available or being developed: ▪Forging, ▪Machining, ▪Injection Molding, ▪Die Casting, ▪Investment Casting, ▪Metal Forming, ▪Heat Treating, ▪Assembly Tolerancing By utilizing the same 3-D solid model and finite element modeling tools used by the designer, coupled to powerful analysis simulation tools to predict the transient nonlinear heat transfer and plastic material flow found in many manufacturing processes, the manufacturing engineer is able to explore alternative processing plans, evaluate trade-offs and even influence the design to produce superior products. Process simula...

What is Computer‐integrated Manufacturing?

Abstract: In recent times data processing systems have become increasingly powerful and rapid advances have been made in machining and processing technologies. Growth in materials requirements planning (MRP) and computer‐aided design (CAD) has developed in parallel but independent of the advanced manufacturing technology stream. If organisations are to reduce their reaction time to customers’ orders and to provide a truly flexible service these two main streams must be brought together. This is likely to occur through computer‐integrated manufacturing (CIM). An analysis of the various definitions of CIM is given and implies that there is no single “right” definition which can be applied to any organisation. However there are certain principles which apply to definitions of CIM and an attempt is made to highlight these principles. CIM is not limited to the manufacturing function. It must be an overall concept that takes account of every aspect of the business, tying all aspects and organisational functions together into an integrated system, where all necessary data can be accessed easily by those who need them. CIM does not necessarily mean total computerisation but computers and software will play a major part.

A job scheduling model for a flexible manufacturing machine

Abstract: The problems addressed in this paper arise in industry when flexible, automated machines are used to manufacture parts (jobs). These machines include numerically controlled (N/C) tools, robots,...etc. The goal is to avoid unnecessary set-up operations in order to effectively utilize the michines. In this paper we focus on developing a job scheduling model that considers the tool requirement of each job in an explicit fashion.

The analysis of flexible manufacturing systems for reliability

Abstract: Flexible manufacturing systems (FMS) constitute a considerable capital investment which must be fully utilised by uninterrupted production. The analysis of reliability at planning and development stages in the implementation of FMS is essential, since it can change both the system design and the operating philosophy to give improvements in the overall system performance. The main objective of this paper is to propose a technique for assessing the reliability of flexible manufacturing systems and further to discuss the unsuitability of the traditional reliability techniques in the study of such systems. It is shown that simulation studies in thereliability of flexible manufacturing can be applied in the analysis of alternative approaches to system design. The key terms, ‘Manufacturing Capability’, ‘Production Efficiency’ and ‘Demanded Production Lead Time Success Ratio’ are introduced as measures which can assess a system's performance. A typical flexible manufacturing cell is then analysed for reliability using predicted reliability data. The effect of equipment redundancy, buffer stock size and production priority rules on the cells performance are finally discussed.