Feasibility Study of High-speed Ultrasonic Vibration Cutting Titanium Alloy

For a series of unique properties, titanium alloy is widely applied in aviation and aerospace fields. However, the poor machinability makes high-speed machining titanium alloy hardly perform as expected even with advanced tool materials due to the high cutting temperature. Intermittent cutting could be an effective method to decrease the cutting temperature and improve the cutting performance. As typical intermittent cutting methods, traditional ultrasonic vibration cutting (UVC) and elliptical ultrasonic vibration cutting (EUVC) is achieved significant advancements. However, the critical cutting speed confines them to the field of low speed machining. A new type of ultrasonic vibration cutting is proposed, i.e. high-speed ultrasonic vibration cutting (HUVC), in which the vibration is always along with the feed direction. The separation of the tool and workpiece can be realized under some certain conditions although the cutting speed exceeds far away from the critical speed of the traditional UVC and EUVC methods. As a consequence, it realized high speed cutting on a macro level and intermittent cutting in the micro, and improved the machinability of titanium alloy. Firstly, a model of HUVC process was established. Then the feasibility of HUVC method for cutting Ti-6Al-4V is verified experimentally compared with conventional cutting (CC) and traditional ultrasonic vibration cutting (UVC). The results demonstrated that tool life in HUVC are extended by 300% in an optimal situation due to the significantly tool wear reduction. Besides, the cutting efficiency is increased by 90% and cutting force is reduced up to 50% obviously compared with CC method. Furthermore, better surface roughness improvement in a successive cutting process are also achieved.