A dynamic two-axis interpolation test with linear and rotary axes in five-axis machine tool

This paper presents a new dynamic two-axis interpolation test method for dynamic accuracy calibration of rotary axis in a five-axis machine tool based on the double ball bar(DBB). The proposed method only requires synchronous movement of a single rotary axis and a single linear axis which is parallel to the average line of the rotary axis. The measurement trajectory is a spatial curve formed by the intersection of spherical and cylindrical surface, which are the reachable operating space of the DBB and the reachable operating space of the two moving axes, respectively. Compared to the circular tests described in ISO10791.6, which need at least three axes to synchronize motion, the proposed method can be effectively applied to the matching of servo parameters and the adjusting of the dynamic errors of the rotary axis, without the interference of additional linear axes. Meanwhile, the error trajectory pattern obtained by this method has the characteristics of orthogonality and regular variation, which is similar to the circular test of linear axis. So it can guide the calibration and optimization of rotating axis conveniently and effectively. Simulation results show that the proposed method can effectively identify the inverse error, scaling mismatch error, servo mismatch error, squareness error, and other error sources of the rotary axis. The proposed method is verified through experiments on a five-axis machine tool.