PIM — Skeletal plan-based CAPP

Abstract

In order to create a production plan from product model data, a human expert thinks in a special terminology with respect to the given workpiece and its production plan. He identifies certain areas of interest, the so-called application features. The exact form of these features is influenced by his manufacturing environment (e.g. available tools) and by his personal experience. The expert associates the application features with fragments of a production plan. By combining these fragments, bearing in mind some general principles, he creates the complete production plan. We present a set of representation formalisms which allow to model this approach very closely. Based on a general geometrical/technological representation formalism, an expert's personal terminology is described in terms of features. Skeletal plans (abstracted plans or fragments of plans) are associated to these features. The generation of a production plan consequently boils down to a sequence of abstraction, selection and refinement: The geometrical/technological representation of a workpiece allows the recognition of the relevant features. The associated skeletal plans are selected, merged and refined until a complete plan is created. This is demonstrated in the CAPP system PIM (Planning In Manufacturing), which has been developed as a prototype.