Abstract: Currently existing tool path planning algorithms may result in large variations of tool rotation axes in five-axis machining of free-form surfaces, leading to problems of non-linear errors and acceleration and deceleration of rotation axes. Aiming at solving these problems, an algorithm of optimization of rotation axes is proposed after analyzing the relationship between values of rotation angles and non-linear errors. Values of rotation angles can therefore be taken as the criteria for determination of areas that should be optimized and the corresponding regions are defined by regional recursive extended principle. While the positions of tool tips are still maintained, rotation axes are changed according to the principle of equal rotating amount. Results show that the algorithm has advantages of less machining errors, shorter machining time, and higher machining efficiency.

Key words: Five-axis CNC machining, Free-form surface, Optimization of rotation axes, Rotation axis, Tool orientation error