Effect of dynamic response and displacement/stress amplitude on ultrasonic vibration cutting

In this report, the behavior of the cutting force measured through the dynamic response of tool-work piece system in ultrasonic vibration cutting was discussed first. Measured cutting force mainly depends on the ratio of net cutting time to a vibration cycle in vibration cutting (t(c)/T) because the tool-work piece system has much lower natural frequency comparing with the ultrasonic vibration cycle. It was confirmed by the newly proposed cutting experiment using resonated-horn-type work piece, displacement amplitude and stress amplitude at the cutting point vary continuously in this device. It was shown that the measured cutting force varies corresponding to the displacement amplitude. It was also indicated that the measured cutting force does not decrease when the cutting point is on the node of the resonated-horn-type work piece, where the stress amplitude is the maximum but there is no displacement amplitude. It means that there should be the relative intermittent displacement between the tool and the chip in order to decrease the measured cutting force. In addition, the deformation resistance of the work piece material itself does not decrease with ultrasonic vibration of the stress field. Secondly, the significance of the elastic deformation of the tool-work piece system of several microns in ultrasonic intermittent cutting was also indicated from an analytical and experimental point of view. The effect of the elastic behavior on the cutting force becomes relatively large as t(c)/T becomes small. The above-mentioned characteristics will be helpful to utilize the ultrasonic vibration cutting system more efficiently. (C) 2008 Elsevier B.V. All rights reserved.