Papers by Author: Rong Ming Lin

Abstract: So far, the industrial application of ultrasonic vibration assistance has been successful in continuous machining process such as turning process where ultrasonic vibration velocity is much higher than cutting velocity. Recently, vibration assistance has been experimentally investigated to the intermittent milling process mainly for feed and cross- feed directions. This paper focuses on the effect of ultrasonic vibration assistance in spindle axial direction for improvement of machined surface. With the designed ultrasonic vibration assisted milling process with 39.7 kHz and a few micro-meter amplitudes, workpiece vibrates along spindle axial direction while different RPMs and feed rates are applied. The axial directional vibration assistance acts as additional cutting motion which further reduces the leftover surface error. Experimental results validate that surface roughness can be improved from 20 % to 65 % for the tested conditions. Apparently chatter marks of the milling process are reduced with the help of the axial ultrasonic vibration assistance.

Abstract: One-directional ultrasonic vibration assisted milling system is designed and its performance is investigated in terms of machined surface quality under 135,000 rpm. The ultrasonic vibration generator excites the workpiece with a frequency around 40 kHz and amplitude of a few micro meters. The milling tool’s cutting speed is controlled by an air-bearing spindle system. Both feed-directional and cross-feed directional ultrasonic vibration assistance are considered in order to understand the mechanism of ultrasonic vibration assistance for surface roughness generation. A comparison is done on a milled surface which is generated with and without ultrasonic vibration assistance. The experimental results show that ultrasonic vibration assistance can improve the machined surface quality which depended on the cutting edge radius and the feed per tooth.