In Situ Measurement of Spindle Radial and Tilt Error Motions by Complementary Multi-probe Method

This paper presents a complementary multi-probe method for measurement of radial and tilt error motions of a spindle. Neither indexing of artefact nor rotating of spindle housing is required and thus make it suitable for in situ evaluation of spindle performance effectively. In order to minimize the harmonic suppression problems commonly encountered in the multi-probe measurement approach, three sets of probe angle combinations were optimized and the harmonics of the three measurements were extracted and composed to reveal the true artefact errors in a complementary way. The exact probe angles were identified by the correlation function of the probe signals after the sensors are mounted onto the fixture and the requirement of high-precision fixtures was alleviated. The evaluation of measurement results showed that the erroneous harmonics were greatly reduced by 70%. Using this method, the radial error motions of the precision air bearing spindle were measured at seven axial positions and then the synchronized tilts error motions were calculated. This demonstrated an effective approach for measuring four degree-of-freedom error motions in one setup with a small number of displacement sensor probes.