An approach for improving machining accuracy of five-axis machine tools

The geometrical error of rotation axis is a fundamental error source for five-axis machine tool (FAMT). Therefore, enhancing the accuracy of rotation axis is one of the important means to enhance the machining accuracy of FAMT. This paper developed a novel approach for geometric error identification of rotation axis. Firstly, a single axis rotation identification model using double ball bar is established based on Homogeneous Transformation Matrix (HTM) theory. Secondly, the five measurement trajectories are developed to determine the geometric errors of the C-axis. In addition, the fourth-order truncated Fourier series is used to fit the discrete measurement data under the premise of considering the installation error of the double ball bar instrument. Finally, simulation and experiments indicate that the proposed method is effective and feasible. The SSE values of the fitting model are above 90.39. In the compensation experiment based on identification method, the average machining accuracy of workpiece has been improved by 28.6% compared with RTCP.