Volume Journal ~tMan~facturing. Systems

Cumulative Abstract Index

frame data to solid geometric, which would give the combined advantages of easy data input and the enormous descriptive power of solid geometric form. How the translated data could be interpreted and coded for manufacturing applications is also explained. The concept of a generalized shape descriptor has been introduced in this context. Keywords: Interpretation of Shapes, CAD/CAM, Assembly, Robotics

Automated Design of Modular Fixtures for Flexible Manufactur- ing Systems, M. Gandhi, B. Thompson, pp. 243-52

The absence of adequate flexible fixturing methodologies is a significant impediment to the evolution of truly flexible manufac- turing systems. Modular fixturing is one of the principal emerg- ing technologies which address this void in computer-integrated manufacturing. A methodology is proposed for the automated

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several distincdy different disciplines. The complexity of this challenging frontier problem is discussed, and the interdiscipli-

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Manufacturing Systems, CAD/CAM

The Application of Lognormal Models of Transient Operations in the Flexible Manufacturing Environment, W. Wilhelm, pp. 253-66

Fundamental aspects of models that might be used to design and/or manage operations in the flexible manufacturing environ- ment are presented, and demonstrated in hypothetical examples. Suggested applications are in the coordination of production and assembly operations so that lots are completed as scheduled with minimal levels of in-process inventory. Specific examples in- clude coordinating the delivery of components required to as- semble a product, analyzing the throughput and productivity of a robotic cell, and managing the flow of materials amongst cells. Numerical tests in these contexts indicate that the modeling approach, which approximates transient as well as steady state operations, gives results that compare favorably with those de- rived from a simulation model at a substantial runtime advantage. Keywords: Flexible Manufacturing, Transient Operations, Recursion Models, Maximum Lognormals, Robotic Cells

1987~ V o l . 6 / N o . 1

Implementing the Automated Factory, J. Meredith, pp. 1-13 Some of the major difficulties in implementing the automated

factory, sometimes referred to as the factory o f the future, are addressed here. A generic implementation plan is formulated and the major impediments are described. These include an assess- ment of the firm's readiness for automation, conducting the "as is" study, and attending to the automation infrastructure and organizational interfaces. Keywords: Implementation, Factory of the Future, Automation, Manufacturing, Technology, Infrastructure

Effect of Process Unreliability on Integrated Manufacturing/ Production Systems, M. Lulu, J. Black, pp. 15-22

The effects of process unreliability on the performance of a simulation model of an integrated manufacturing production

system operating in a just-in-time mode is investigated. In a multicomponent manufacturing and assembly environment, poorer process reliability results in a pronounced lower level of system utilization. Work-in-process inventory-induced gains in produc- tion rates are not as significant as may be envisioned in traditional production systems that essentially operate under "push system" production control. Keywords: Integrated Manufacturing, Just-In-Time Production, Process Unreliability

A Case Study in Parallel Unrelated Machine Scheduling: A Heuristic Approach, M. Dessouky, Y. Dessoulcy, M. Dessouky, pp. 23-36

This article describes a heuristic algorithm that generates weekly production schedules for packaging a number of products on parallel unrelated lines. Various constraints are imposed, including restrictions on the total number of lines that can run simultaneously, product families that can be processed concur- rently, total run hours per shift, and available material. Special consideration is given to weekly startup learning coefficients, changeover learning coefficients, changeover times, shutdown hours, and a host o f other factors. The objective is to maximize weekly output or to minimize the time to produce weekly demand, whichever is applicable. Keywords: Macldne Scheduling, Heuristic Algorithms, Decision Support Systems, Production Schedules

Integration of a Group Technology Classification and Coding System with an Engineering Database, R. Billo, R. Rucker, D. Shunk, pp. 37-45

Five tools that apply group technology concepts to an engineer- ing database were investigated and compared. The purpose of the investigation was to select the tools with the best ranking in the areas of cost, flexibility, and ease of use. These tools were applied to engineering data from an aircraft structural composites classi- fication and coding schema. The tools include a vendor supplied GT software package, a GT classification schema mapped onto a relational database, a GT classification and coding schema mapped onto a relational database, and a custom developed GT package which directly accesses a relational database. It was concluded from a comparison of five GT design tools that the custom developed GT package was the most advantageous design tool based on evaluation factors which included cost, flexibility, and user-friendliness. Keywords: Group Technology, Relational Database, Integration, Engineering Database

Optimization era Complex Flow Line for Printed Circuit Board Fabrication by Computer Simulation, L. Lin, J. Cochran, pp. 47-57

The complex operations and considerable process time vari- ability of pnnted circuit board (PCB) fabrication create difficul- ties in finding effective and efficient planning techniques for today's PCB production management. A great deal of money is involved. By modeling and testing a real world PCB fabrication facility, this paper shows that computer simulation can provide a viable planning tool to estimate production capacity and to explore optimum arrangement in batch work size of key bottle- neck machines to minimizeproduct throughput time. Many simulation experiments are performed and the results analyzed as a response surface. The general characteristic of product through- put time is found to be that its minimal value exits when batch job numbers of subsequential key machines are matched in batch size or in multiples thereof. A nonlinear empirical equation to esti-

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