A smooth double spiral tool path generation and linking method for high-speed machining of multiply-connected pockets

Complex pockets have been widely used in industry for the production. At present, the basic forms of tool-path which most commercial CAM software systems used are still limited to direction-parallel and contour-parallel offset. If the pocket contains multiple islands, the tool-path will include many cutter lifting and retraction motions. In this paper, we propose a new double spiral tool-path generation and linking method for complex pockets with multiple islands which can be used for high speed machining. We also provide segmentation rules to divide surface for further improving machining accuracy and efficiency. Taking into account the path interval, step length and other processing parameters, precise milling can be achieved without cutter lifting and retraction operations to ensure optimal processing performance and reduce processing time. The proposed algorithm has been implemented and tested bounded by 2D straight lines and circular arcs of various shapes, and validated successfully through the actual machining of a complicated pocket. The results indicate that this method is superior to other existing machining methods, and it can realize high speed machining of complicate-shaped pocket based on parametric surface with multiple islands.