Error Sensitivity Analysis of Motion Axis for Five-axis CNC Machine Tools with Geometric Error Contribution

Aiming at the problems that the sensitivity analysis of the existing error elements was not closely related to the subsequent error compensation,the geometric error contribution modeling of the motion axes and error sensitivity analysis of the motion axes were built to obtain the key motion axes whose geometric errors had great influence on the accuracy of the five-axis CNC machine tool. The geometric error contributions of all motion axes were established based on the error sensitivity matrix by using POE(product of exponential) theory and the transforming differential changes among coordinate frames. The integrated geometric error model of the CNC machine tool was the summation of the error contribution of all motion axes. The weight components and the comprehensive weight of error contribution for all motion axes were calculated to realize the error sensitivity analysis of the axes. The motion axis with the maximum mean comprehensive weight was selected as the key motion axis of the CNC machine tool, and the error compensation method of the key motion axis was analyzed and discussed. Finally, simulations and real cutting experiments were carried out on five-axis CNC machine tool of JINGDIAO. The results show that geometric error contribution modeling and error sensitivity evaluations of the motion axis are effective, and only compensating the geometric error contribution of the key motion axis may effectively improve the accuracy of the five-axis CNC machine tool. © 2020, China Mechanical Engineering Magazine Office. All right reserved.