A tool orientation smoothing method based on machine rotary axes for five-axis machining with ball end cutters

Abstract

Avoiding significant fluctuations of tool orientation is an important problem in five-axis machining. The dramatic change of tool orientation may greatly increase the angular acceleration of machine rotary axes, produce larger nonlinear machining errors and gouging, reduce the feed rate of machine rotary axes, etc. In this paper, we propose a tool orientation smoothing method based on machine rotary axes for five-axis machining with ball end cutters to reduce fluctuations of tool orientation in the machine coordinate system (MCS). The core idea of the proposed method is to directly smooth machine rotary angles in the machine coordinate system for the smooth variation of tool orientation. First of all, we establish the relationship between the design variables of tool position and machine rotary angles. Then, we define an objective function of tool orientation smoothing based on machine rotary angles. In order to solve the above objective function, we also develop a simplified algorithm to obtain the minimum sum of squares of compound angular accelerations. Finally, a blade surface is used as a test example, and tool paths are generated by the Sturz and proposed methods, respectively. Comparison and analysis results show that the proposed method can improve the kinematics performance of five-axis machine tool, as well as surface machining quality and efficiency.