Evaluation criteria: a method to represent and compute technological knowledge in CAPP

The complexity of research in CAPP is, on the one hand, about the knowledge formalization of the machining expert (knowledge based on scientific models but also on experience) and, on the other hand, about the use of this knowledge to obtain a system of CAPP for general machining (knowledge valuation). The authors´ method is based on three tools which allows them to: represent the process plans, describe the knowledge of a machining expert, and imagine process plans. A study of the finished part allows one to conceive many anterior stages of the workpiece and, by successive iterations to obtain raw shapes. This way, technological criteria translate machining expert knowledge, and compute and eliminate non-viable solutions step by step. The graph of representation of process plans, finally obtained, has only a few technologically viable process plans. A global evaluation can then be executed (cost study for example). In this paper, the authors develop the evaluation criteria and the construction of the graph to avoid a combinatorial explosion. The authors´ experimental software LURPA-TOUR uses this method on a IBM RISC 6000 computer for turning parts