Macro-CAPP: a CAPP CIM interface

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1988
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Virginia Polytechnic Institute and State University
Abstract

There exists today a variety of Computer Aided Process Planning (CAPP) systems that have been designed, developed, and implemented irrespective of the facility's condition and status. It is often found in practice that Computer Integrated Manufacturing (CIM) constituents such as production control, loading, sequencing, scheduling, etc. do not interact with Computer Aided Design (CAD), Computer Aided Manufacturing (CAM), or CAPP. They operate as stand alone techniques that are not interrelated in the CIM scenario. This could be overcome through increased, improved communication between CAD, CAPP, CAM, and other CIM constituents.

CAPP has to be tied into the computerization of other CIM functions. An approach in this direction is what this research presents. Its uniqueness is that it relates CAPP in a flexible manufacturing system atmosphere with scheduling, in effect relating CAPP with production control. It integrates process selection and route generation with factors such as facility congestion, work in process, flowtime, machine utilization and dynamic shop conditions.

The generation of alternate routes, and the incorporation of this technique in a CAPP system is an unique approach to the problem of interrelating CAPP with other CIM components. This involved the design and development of software that can model facility capacity, understand part construction, maintain and track shop status, reason through the facility capacity to arrive at possible machining sequences and job routes, and apply a heuristic to arrive at the job route through the facility. This results in the introduction and implementation of the concept of dynamic scheduling and alternate route generation in CAPP systems.

The objective in global terms was to construct a CAPP system that considers routing and production control for a FMS that consists of several high capacity, modern machines. The concepts mentioned above are combined and coalesced in a CAPP system that truly provides computerized assistance to the process planning function at a macro-level. This research attempts to create a truly integrated CAPP system within a CIM atmosphere.

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