Automatic unbalance correction of rotors by sympathetic phase inversion of ultraviolet-curing resin

We developed an automatic unbalance correction technique for unbalanced rotors using a sympathetic phase inversion of ultraviolet (UV)-curing resin. Correcting the unbalanced weight during production is essential for various industrial rotors. The reduction of the cost and time of the correction process of unbalance during production is of great importance; however, the correction must have high precision, particularly for low-cost rotors such as polygon scanner motors and hard disks. In this paper we propose a new technique for correcting the unbalance of polygon scanner motors. Our system rotated a rotor on a translational oscillation table at a speed higher than that of the resonance rotation speed. The rotor exhibited runout opposing the unbalanced weight at this speed, and UV-curing resin preliminarily injected into the rotor also positioned itself opposite the unbalanced weight. UV light at this point cured the resin to immediately counter the unbalanced weight. Our experimental system confirmed the feasibility of this correction technique and reduced the unbalanced weight to 20% of that before the correction. This was in good agreement with the theoretical analysis.