Machining process planning of prismatic parts using case-based reasoning and past process knowledge

Abstract

A process planner for three-dimension prismatic parts is developed in this paper by utilizing case-based techniques. A three-dimension prismatic part is represented by a set of primary features (such as holes, pockets, slots, etc). The subplan candidates for individual features of a part are first generated by the proposed system via a backward inference planner based on the specifications of cutting tools available in a factory. The system then combines all subplans into the final process plan for a given part based on the merging information. The merging information is the information regarding the manufacturing environment of a factory (i.e. machine layout, transfer line, etc), and plays a key role in the process planning. Generally, the merging information is contained in old plans, and will be extracted by the system using case-based techniques. This way, the proposed system can generate a practical process plan for a given part based on case histories provided by the factory itself. The proposed process planner is composed of five major components: feature indexer, retriever, modifier, simulator, and repairer. It is implemented on a Sun workstation using the ACIS geometric modeler and C++.