Greedy tool heuristic approach to rough milling of complex shaped pockets

The milling of complex pockets bounded by NURBS surfaces is usually broken into rough and finish milling, with the former taking up the bulk of the machining time. The total machining time can be reduced if the proper combination of end-mills of different sizes are used to machine in different regions. This paper presents a new greedy tool heuristic approach to the determination of the machining volume that should be allocated to different tools selected from among a large set of available tools. Subsequent machining planning can then be performed by repeated application of standard 2-D milling algorithms. The proposed new approach of multi-tool rough milling promises to reduce the machining time of complex shaped parts such as molds and casting patterns. The presented techniques can be used in CAD/CAM systems to automate NC tool path generation for complex pockets machining.