A new machining test to identify position-independent geometric errors of rotary axes for five-axis machine tools

Rotary axes of five-axis machine tools have highly coupled geometric errors, which are crucial factors affecting the machining accuracy. In this study, a new feature workpiece is designed, including two features of arc surface and square groove. Based on the on-machine measurement of the workpiece, five position-independent geometric errors of the two rotary axes can be identified. The cutting and measuring steps of the workpiece are described in detail, the identification principle of each error is revealed, and the uncertainty analysis is carried out. During the identification process, the machining domain and measurement domain of the same feature remain unchanged to eliminate the influence of linear axis errors on the identification results; hence, the identification accuracy is improved. In the experimental verification, the result is 90.8% consistent with the ball-bar method, which verifies the feasibility of this method.