Single spherical angle linear interpolation for the control of non-linearity errors in five-axis flank milling

Abstract

Five-axis machine tools have two additional rotary freedoms compared with the traditional three-axis machine tool, and it is widely adopted for manufacturing parts such as turbine blade. However, five-axis machine tool has more complicated problem than three-axis machine tool, for example, non-linearity machining error. The non-linearity error is always defined as the maximum deviation of cutter location (CL) point from the theory programming plane. But sometimes, the deviation of tool orientation from the theory programming plane has more influence on machining precision, for instance, in five-axis flank milling. In this sense, the purpose of this paper is to avoid the tool orientation out of the theory programming plane by using a new method called SSALI. Firstly, the reason causing non-linearity error in five-axis flank milling is explained by illustrating the tool orientation interpolation between two adjacent CL points. Secondly, a kinematics model of rotation axis is developed to describe the generating process of non-linearity error, and a single spherical angle linear interpolation (SSALI) method is proposed. Then, the optimization algorithm is established to avoid the non-linearity error. Finally, the algorithm is implemented and verified experimentally in a five-axis machine tool. The results show that the maximum error value can be greatly decreased by using the method in this paper.