Volumetric error compensation model for five-axis machine tools considering effects of rotation tool center point

Conventional volumetric error compensation strategies for five-axis machines directly generate compensation values without considering the RTCP (rotation tool center point) effects, which causes additional movements of translational axes with the movement of rotary axes, so the compensation values for three linear axes need to be recalculated. In this paper, a volumetric error compensation model considering RTCP is proposed. In the model, the compensation values for translational axes totally consist of three parts, i.e., position errors caused by the volumetric error, position variations caused by the compensation of rotary axes, and caused by RTCP. Firstly, the compensation values for rotary axes are obtained based on the volumetric error model and the inverse kinematics. Then, the compensation values for three linear axes are calculated in detail based on the compensation values of rotary axes and RTCP effects. Finally, ballbar tests of a cone-frustum toolpath are selected to verify the proposed compensation model.