New method to measure angular position errors of rotational axis of CNC machine tool

In order to carry out the error compensation of multi-axis machine tools, this paper presents a novel measurement method, a combined paths measurement method (CPMM) based on ball bar, to identify the angular position errors of a rotational axis of a machine tool. According to the error sensitive direction, angular position errors could be directly identified by combining the tangential direction measurement and circular path measurement of translational axes without a mathematical error model of a machine tool and the complicated error decouple process. The simulation and contrast experiments were conducted to verify the feasibility and reliability of the method. The results show that identified value by CPMM is consistent with that by laser measurement method, the maximum difference is 0.007 8°. The operation process of CPMM is simple and its corresponding identification algorithms are easier to understand. The established measurement method can be used for the precision evaluation of a rotational axis, and provide the basis for the error compensation to improve machining precision of machine tools. ©, 2015, Zhejiang University. All right reserved.