Abstract
A new method for inducing a machine spindle to vibrate ultrasonically was proposed. Rather than using piezoelectric or magnetostrictive transducers, common in conventional ultrasonic vibration spindles, the new method utilizes a fluctuating electromagnetic force to induce the spindle to vibrate ultrasonically along its axis. An experimental rig was constructed to confirm the generation of the ultrasonic vibration. Following the measurement of the fluctuating magnetic force, axial ultrasonic vibration generated on the spindle was investigated for various conditions such as the frequency and magnitude of the applied electric power and the gap between the electromagnet and the spindle. As a result, it was found that: (1) the magnetic force increases as the electric power increases but decreases as the gap increases; and (2) the spindle vibration amplitude shows the same tendency as that of the magnetic force. The maximum vibration amplitude obtained was 5.4 μm.