Machinablity improvement with ultrasonic vibration-assisted micro-milling

An ultrasonic vibration-assisted micro-milling with horizontal vibration of workpiece is investigated in this article. A vibration platform with maximum amplitude of 15 mu m based on universal ball support structure is designed and built by our group. Titanium alloy TC4 and aluminum alloy 6061T6 were chosen as workpiece material. Series of slot-milling experiments were conducted with and without vibration at different amplitudes and feed rates to explore the effects of vibration on the micro-milling. Experiment results showed that ultrasonic vibration can effectively reduce milling force by 12% and 17%, respectively, for aluminum alloy 6061T6 and titanium alloy TC4 compared with that of conventional milling and hence leading to a better machining accuracy and longer tool life. Furthermore, the effect of ultrasonic vibration on titanium alloy is much more obvious. The topographies of machined surfaces also showed that ultrasonic vibration can reduce surface defects and machining marks and thus improve the surface quality for both 6061T6 and TC4. Besides these, it is worth to be noted that ultrasonic vibration leads the size effect point appear at much lower feed rate than conventional milling, which means vibration brings a change to machining mechanism and delays the appearance of micro-milling.