1.2 THE OBJECTIVES OF CAPP SYSTEMS

Eversheim and Shulz [1985] have done an extensive survey on the use of CAPP systems by industry. Their paper identifies a number of the popular factors considered in CAPP systems. The majority of the systems they surveyed included,

• product costs,

• processing time,

• setup time,

• text strings,

• cutting data,

• machine groups,

• searching similar process plans (Variant),

• determination of raw materials,

• selection of operations,

• segmentation of cut,

• rate settings.

There were other less popular features found in some of the other systems,

• machine adjustment data,

• partial operations,

• wage groups,

• fixture information,

• accounting information,

• plan editing.

While these do not represent all possibilities considered within a CAPP system, they do indicate the features that are of importance to industry. Eversheim and Schulz also identify the major domains of CAPP systems. The most popular is rotational parts, followed by prismatic parts, sheet metal, assembly, etc. Their figures indicate a definite lack of multi-domain CAPP systems. Their paper also indicates that 70% of CAPP systems are used in facilities that focus on single part and batch production.

A classification scheme for process planning was also suggested in Eversheim and Schulz [1985]. They divided CAPP functions into three major divisions, with sub-divisions;

• Process Planning,

- determination of the raw material,

- selection of operations,

- determination of machining groups.

• Operation Planning,

- selection of partial operations,

- determination of technical data,

- time and cost calculation.

• Management Functions,

- retrieval of similar process plans,

- duplication of process plans,

- modification of process plan data.

They present a table of the surveyed systems using the classifications given above. A larger table was presented by Alting and Zhang [1988].