Operation decomposition for freeform surface features in process planning

Machining operations for freeform surface features usually include roughing, ®nishing for the bottom surface, tapering, and corner rounding. Strategies and algorithms to decompose the overall task into these operations are presented. The decomposition aims at minimizing machining time within the constraints of the speci®ed surface roughness and tolerance, and machine tool safety. The roughing operation can be further decomposed into sub-operations for multiple tools. There are two strategies to decompose the ®nishing operation into suboperations: one is based on multiple tools and another is based on multiple tool path patterns. The approaches to select the optimal decomposition values (tool diameters, surface slopes) that minimize machining time are presented. These algorithms are being integrated into a rapid-prototyping service for web-based machining. Design for manufacturability and maximizing process automation are the key priorities in process planning and operation decomposition. q 2001 Published by Elsevier Science Ltd.