Separating machining errors of S-shaped samples based on the comprehensive error field of five-axis machine tools

In the present study, a new method is proposed to separate machining errors of a 5-axis machine tool with a double turntable. Moreover, a high-precision compensation model is established to calculate machining errors of thin-walled parts in a 5-axis machine tool. In this regard, a comprehensive error model of the S-shaped sample part considering geometric, thermal, and machining errors is established. Then based on the homogeneous transformation matrix, the geometric error models of translational axes and the A and C axes of the rotation axis are established. Accordingly, geometric errors of each motion axes are identified and measured. Meanwhile, the thermal error of the spindle is measured, and the thermal error model of the machine tool along X/Y/Z directions is established using the multiple linear regression method. Finally, the S-shaped sample is processed and the on-machine measurement of the sample surface is carried out. Based on the obtained machining error from the separation method, the distribution of the total surface error at different curvatures of the S-shaped sample is analyzed, and the distributions of geometric and thermal errors of the machine tool are obtained. It is found that when the geometric and thermal errors of the machine tool are compensated, the measured machining error of each point of the S-shaped sample can be reduced by 10-15 mu m compared with that before compensation.