Tool path generation for a car rear door die: UMO versus rest milling tool paths

摘要

Tool path generation for sculptured surfaces that contain many concave and convex features involves gouging and undercut problems. Past research has paid little attention to tool path generation for hard materials, which require careful and precise planning. In this paper, a comparison is made between traditional unit machining operation (UMO) and rest milling-based tool paths for the various machining steps (roughing, semi-finishing and finishing) of a car's rear door, designed by NURBS surfaces. The experimental work involves the machining of two dies in a 3-axis CNC machine. Each die comprises two parts: punch (convex) and die (concave). Various tool path patterns (contour, zig-zag, zig, concentric zig-zag) are generated and compared via NX8 software. The results show a great saving of time and less tool consumption by using a rest milling technique over UMO techniques.