Rapid generation of contour parallel toolpaths for 2.5D closed cavity based on accurate discrete medial axis transform

Abstract

Contour parallel toolpaths are the most common machining strategies for 2.5D features. To enhance the machining efficiency, different cutting paths for various tool combinations should be considered. However, existing algorithms have paid limited attention to multi-tool cutting, which is nevertheless an industrial practice in roughening and finishing. This paper proposes a rapid generation method for contour parallel toolpaths based on an accurate two-dimensional discrete medial-axis transform (MAT) for complex closed cavities. The accurate discrete MAT was refined using the Delaunay triangulation (DT) method. According to the definition of MAT, the calculated discrete medial axis (MA) points are adjusted to obtain accurate MA points by iterative method. The accurate discrete MAT obtained served as the basis for the toolpath generation. Contour parallel toolpaths can be rapidly generated by applying the discrete MAT and the proposed toolpath generation method. The resulting toolpaths have been validated to closely match the cutting path obtained through commercial software calculations, which require much higher computational efforts. The proposed method introduces a novel accurate discrete medial axis calculation method and enables the rapid computation of multi-tool combination cutting paths., which is more suitable in toolpath generation, cutting time prediction and toolset optimization in practice.