Research on geometric error compensation of ultra-precision turning-milling machine tool based on macro–micro composite technology

In this paper, the geometric error modeling and compensation methods of macro–micro composite five-axis turn-milling composite machining center is studied. Firstly, the machine topological structure of the branches, intermediates, and terminal bodies of the macro–micro composite multi-body system is analyzed. Then, the tool chain transformation matrix and the end position of the workpiece chain are established to obtain the geometric error model. Based on the error compensation theory of traditional machine tool structure, the compensation mechanism of macro-level compensation and micro-level sub-micron compensation is proposed. Then, the compensation model of micro-axis error is given. Furthermore, the macro–micro composite error compensation experiment is setup; the laser interferometer is used to judge the positioning accuracy and straightness before and after compensation. The results show that the accuracy of the micro-motion platform after compensation reaches the sub-micron level, which verifies the compensation method, and the machining accuracy of the micron level is achieved through the cutting experiment.