Five-axis tool path generation based on machine-dependent potential field

Abstract

Traditional methods for improving machining efficiency in five-axis machining mainly concentrate on two frontiers. One seeks to minimise the total length of the tool path, while the other aims at maximising the feedrate. These two optimisations are carried out independently at different stages of a machining process and often conflict each other. Explicitly, a tool path with minimum total tool path length may turn out to be inferior when the specific machine tool’s capacities are considered, and, in order not to exceed the limits of those capacities, the machine’s controller has to keep the feedrate under an inordinately low level, thus actually prolonging the real machining time. In this article, by considering the local geometry of the part surface and the speed and acceleration limits of the machine’s axes, a vector field called machine-dependent potential field is proposed to characterise the relationship between the material removal rate and the feed direction. Based on this introduced potential field, and combined with the well-known iso-cusp height expansion method, a new five-axis tool path generation algorithm is proposed. Preliminary experiments show that this new algorithm can sometimes achieve substantial savings in total machining time over the existing methods.