Optimisation of CNC Machining Part Programs Exemplified for Rough-Milling of Pockets

A three-stage, comprehensive yet lean methodology for optimizing CNC machining is presented by example of rough cutting a complex pocket in a steel part to minimize machining time. First, CAM software is used for toolpath planning according to experience. Second, Taguchi method determines the best values of toolpath parameters (depth of cut, overlap, cutting pattern and cutter diameter) and their relative importance on the pertinent criterion, in this case machining time. In the third stage, machining parameters, i.e. cutting speed, feed per tooth and depth of cut were optimized by a genetic algorithm. The objective function included machining time, while taking into consideration technological and quality constraints, i.e. power, surface roughness and dynamic stability. The approach is demonstrated through CAM-based simulation.