Uncut free pocketing tool-paths generation using pair-wise offset algorithm

Abstract

For die-cavity pocketing, contour-parallel machining is the most popular machining strategy. Two issues in generating contour-parallel tool paths for pocketing are: (1) a robust two-dimensional (2D)-curve offsetting algorithm; and (2) detecting and removing uncut regions. The 2D-curve offsetting solution has been widely studied, because it has so many potential applications. However, though the importance of the uncut problem in pocketing has long been recognized there have been few reported investigations on detecting and removing uncut regions. This paper presents a procedure for generating pocketing tool paths leaving no uncut regions. For the 2D-curve offsetting algorithm, we employ the PWID offset algorithm suggested by Choi and Park (Computer Aided Design, 31(12) (1999) 735) and expand the algorithm for offsetting areas having islands. Based on the expanded PWID offset algorithm, our solution to the uncut problem removes the uncut regions. Empirical tests show the usefulness of the proposed procedure for improving the productivity of pocket machining.