COMPENSATION OF SPINDLE UNBALANCE-INDUCED VIBRATION USING AN ELECTROMAGNETIC EXCITER

Recently, high speed cutting technology is widely adapted in the manufacturing process due to the increased demand of quality and productivity. Well-known high-speed cutting systems are motorized spindles. It is convinced that the profile of spindle rotation changes over the period of time due to the tool wear or tool change, which deteriorates not only machining quality but also tool life significantly. Therefore, automatic spindle balancing with respect to the spindle rotating condition becomes an essential requirement for high speed and high precision machining systems. This paper presents an automatic compensating scheme for spindle unbalance using an electromagnetic exciter (EME). The proposed scheme provides several advantages such as compensation of spindle unbalance-induced exciting force, spindle monitoring, and accurate control since it uses non-contact excitation based on electromagnetism. In the proposed system, the spindle unbalance-induced force is measured by vibration sensors and used as the feedback. Accordingly the electromagnetic force is applied to the spindle rotor in the counter side that corresponds with the measured unbalance force. In this paper, to implement the compensating system, the controller is designed and also the spindle-bearing system is built up. The experimental results indicate that the proposed method is very effective to compensate the spindle unbalance-induced exciting force in real time. Key words: compensation of spindle unbalance-induced vibration, electromagnetic exciter (EME), spindle bearing syste