A global tool orientation optimization method for five-axis CNC machining of sculptured surfaces

Dramatic change of tool orientation during a five-axis machining process of sculptured surfaces affects the machining quality seriously. To solve the problem, a global tool orientation optimization method for five-axis machining is proposed based on critical constraints. Firstly, all the feasible swing planes according to the cutter contact points are constructed. Based on the critical constraints, critical tool orientations are obtained in the swing planes, and then the initial feasible tool orientation region is established with planar mapping. Secondly, by evenly discretizing the initial feasible region, an adjacency matrix is constructed according to the relative position relationship of the discrete points. Together with the shortest path algorithm, the initial reference tool orientation is calculated and then a new feasible region is obtained. Finally, the optimization model for tool orientation is established, which guarantees an interference-free current tool path as well as the smallest change between adjacent tool orientations. This method can realize the smooth control of tool orientation for five-axis machining of free-form surfaces without interference. Analysis of two different kinds of impellers with sculptured surfaces demonstrates that the tool orientation obtained by the proposed method can improve the movement performance of machine tools significantly, and the tool interference can be avoided. This method can thus improve the machining efficiency and quality of parts with complicated curvatures.