An iso-scallop tool path generation method for three-axis machining freeform surface

Iso-scallop tool path has uniform scallop height (maximum allowed value) between cutter location (CL) points on the adjacent line, which can maximize interval values of tool path and minimize total lengths of tool path. However, iso-scallop tool path generation process is more complicated than common iso-parameter and iso-planar tool path. In order to avoid exceptions happened in offsetting surface or transforming surface to mesh, this paper generates iso-scallop tool path directly on surface. To improve computational efficiency, based on geometric principle of scallop height and iso-scallop CL points, scallop points are iteratively calculated based on a discrete feature point set including the golden section points. An initial CL location is calculated to be closer to the wanted theoretical iso-scallop point. And an adaptive discretization method is proposed to obtain discrete feature points on surface. The minimum distance from feature points to the CL point is calculated iteratively for the wanted iso-scallop CL point. Both scallop points and iso-scallop CL points are calculated iteratively by a small amount of feature points for efficiency improvement. Two examples of typical freeform surface are used to test the presented method. The results indicate that the scallop height of iso-scallop tool path is uniform, and total lengths are shorter than lengths of iso-planar tool path.