An integrated CAPP/CAM system for stamping die pattern machining

Since the early 1980s, CAPP has been expected to bridge the gap between CAD and CAM. Though numerous research works on CAPP have been reported, it is not easy to ®nd a commercial CAPP system applicable to complicated objects with freeform shapes such as mold and die. The dependency on CAM system is holding one leg of CAPP, while the complexity of the solution space in freeform shape machining has a tight grip on the other. This paper exempli®es that these obstacles on the CAPP bridge can be overcome by the integration with CAM and by focusing on a speci®c application area. Major components of a staming die for the car body panel are manufactured by machining the raw stock castings, which are usually made by the lost foam casting process. Die pattern is the lost foam pattern made of Styrofoam for the raw stock casting. The industry trend is to build die patterns by CNC machining. In this paper, a highly specialized CAPP/CAM integrated system, called Generative Pattern Machining (GPM), for automatic tool paths generation to cut die pattern from the CAD model of the stamping die is described. The overall structure and the detailed steps of GPM are explained. GPM is being used by DaimlerChrysler pattern shop very successfully. q 2002 Elsevier Science Ltd. All rights reserved.