Optimization and selection of cutters for 3D pocket machining

The machining of complex geometrical shapes with a CNC machine tool requires the determination of cutting conditions namely the depth of cut, the feed rate, the cutter diameter, the number of cutters in use, etc. The number and the diameter of the cutters used for the machining of a given pocket has an important effect on the machining time. Consequently, it is necessary to have an algorithm for the optimization of a set of cutters for the machining of a given pocket. This paper is an attempt to determine an optimal set of cutters for the hollowing out of 3D prismatic pockets by means of a CNC machine tool. This approach requires first of all the synthesis of the analytical models developed to calculate the cutting time related to the use of the roughing cutter utilization, the under-roughing cutter utilization, the machining of inner contour corner, and the corner of its bottom. Then, an optimizing algorithm based on these analytical models has been developed. It helps to select the most appropriate set of cutters from the tools available in the production workshop. This algorithm is applied to a particular geometry of a prismatic pocket, and the results show that the optimal choice allows a reduction in the machining time.