Tool diameter optimization in S-shaped test piece machining

S-shaped test piece is used to assess the performance of five-axis numerical control machine tools. Compared to traditional test method and test pieces, it performs better and was agreed to be included in the draft international standard at the 79th ISO/TC39SC2 meeting. However, the lack of theoretical research is the barrier to apply for standard and to be widely used. Therefore, this paper aims to study one of the theoretical research that how to choose the suitable tool diameter. We proposed a new research method based on software AdvantEdge, Vector Method for error calculation, Microelement Model of cutting force and deformation model of cantilever beam. The simulation results show that the 20 <= diameter < 30 is the proper choices and the 20 is the best choice, which is consistent with the empirical consequence. This method not only provides the theoretical support for the S-shaped test piece, but also can be applied to other parts with complex curved surfaces.