Global optimization of sensor installation angles for separating spindle error and roundness

Measuring the motorized spindle's motion error and the rotating parts' roundness are of great significance in machining. However, these two errors are usually mixed in measurement, and separating them is a big challenge. The three-probe method is suitable for on-machine measurement because it does not require the movement of the sensor during measurement. However, there is the problem of harmonic suppression in the three-probe method and harmonic suppression is closely related to the sensor installation angle. This study studied the harmonic suppression phenomenon and gave two performance indicators for angle optimization, optimized the angles in global scope, and gave the best recommended values for the sensor installation angles. A special fixture was designed for precise angle measurement and adjustment, and a cross-correlation analysis method was adopted. Simulations were then created to simulate theoretical errors, rounding errors, and angular uncertainties. Finally, experiments were conducted to verify the discussed errors and results.