Sheet metal cutting and piercing operations planning and tools configuration by an expert system

This paper describes the development of an expert system for both process planning and die design of sheet metal cutting and piercing operations. Knowledge for the system is acquired from practical handbooks, theory and empirical knowledge from industrial partners and is expressed as "crude" rules, transformed by the knowledge engineer into production rules. These are then coded into constructs of the CLIPS expert system development environment. This process is explained using a number of examples. The expert system comprises of five modules: initial calculations (including data input), process planning, finishing operation, die and press selection, and tools selection. Each module draws upon one or more among 18 rule pools defined around the important notions characterising the problem studied. The results of the expert system can be used by both the designer deciding on the production feasibility (manufacturability) for a sheet metal component and by the manufacturer receiving advice either on the hardware needed or on the process plan.