A 'Design for Manufacturing' system for elimination of critical feature interactions on prismatic parts

This paper presents a system that evaluates critical interactions between several types of machining features (i.e. holes, pockets, etc.) on prismatic parts, and modifies original design (if possible) and reflects the modifications to all downstream and up-stream stations in computer-aided design (CAD)/computer-aided manufacturing (CAM) integration. This system can be considered a 'Design for Manufacturing' tool. There may be critical zones between neighbouring features of the prismatic parts. Moreover, location or size of two interacting features may require a special production method. The parts should withstand machining and fixturing forces, and they should not be deformed or deformations should be within tolerable limits. Those critical zones are evaluated by the system for each type of feature interactions based on design criteria. If necessary, some of the features are shifted or removed from the part design to eliminate the critical interactions and, finally, the CAD/CAM database of the component is refreshed correspondingly. The developed system is implemented using C programming language and on an IBM-compatible PC. It can be used as a stand-alone system or as the integrated module of a process planning system called OPPS-PRI (Optimized Process Planning System for PRIsmatic parts) that was also developed for the prismatic parts and implemented on a vertical machining centre. The methodology of the developed system is illustrated with several examples throughout the paper.