An automated CNC programming approach to machining pocket with complex islands and boundaries by using multiple cutters in hybrid tool path patterns

To enhance the efficiency of pocket machining, considerable researches on strategies of tool selection and tool path optimization have been conducted. However, few studies are devoted to tool path planning with consideration of hybrid tool path patterns and multi-cutter selection. This research gap leads to little promotion to industrial application of the available research results. This paper proposes an automated CNC programming approach considering both multiple cutters and hybrid tool path patterns for pockets machining with complex islands and curvilinear boundaries. Firstly, the largest cutter capacity (LCC) of a pocket, which restricts essentially the pocket machining time, is investigated and defined. Secondly, to enlarge the LCC and to generate optimal tool path more easily, the pocket is split into many sub-regions according to the bottleneck lines of its boundary. After subdivision, tool selection and path pattern determination rules for each subarea are introduced, respectively. Then, several heuristic principles for region recombination are developed to minimize the number of sub-polygons. Besides, based on the soft edges of each sub-area, expansion technique is employed to generate machining bounds for residuals. Finally, to demonstrate the advantages of this approach, two examples are rendered. And, the results show that the presented method performs better than the conventional ways.