Study on ultra-precision processing of Ti-6Al-4V with different ultrasonic vibration-assisted cutting modes

Ti-6Al-4V alloy is extensively used in aerospace, biomedical and automotive industries for processing the precise and ultra-precision parts because of its excellent material properties. However, the ultra-precision processing of Ti-6Al-4V alloy has always been a challenge. In this paper, a series of experimental investigations was performed to study the ultra-precision processing feasibility of Ti-6Al-4V alloy with different ultrasonic vibration-assisted cutting modes. The surface defect, surface roughness and chip formation under conventional cutting (CC), ultrasonic linear vibration assisted cutting (ULVC) and ultrasonic elliptical vibration-assisted cutting (UEVC) of Ti-6Al-4V alloy were analyzed. The experimental results revealed that, in the CC process, many surface defects like adhered particles, chip fragments and grooves appeared, and the long continuous ribbon chips were produced. In the ULVC process, the side flow appeared, which greatly deteriorated the surface integrity. Furthermore, the long helical chips were obtained. In contrast, an almost flawless-machined surface was obtained in the UEVC process, and its roughness value was 39.2 nm, which was decreased nearly 31% than the roughness value in CC process and 40% in ULVC process. Moreover, the shorter, helical and controllable chips were obtained. Experimental results indicated the UEVC was applicable for ultra-precision cutting of Ti-6Al-4V alloy.