Analytical modelling and experimental study of surface roughness in ultrasonic elliptical vibration assisted ultra-precision cutting of Ti-6Al-4 V alloy

Ti-6Al-4 V alloy is growing used in the fields of aerospace, automobile and medical industries, and the requirement for machining accuracy of those parts is also increasing. However, it is difficult to achieve ultra-precision cutting of titanium alloy with traditional manufacture techniques. The ultrasonic elliptical vibration assisted cutting (UEVC) is considered the promising manufacture strategy for ultra-precision cutting of Ti-6Al-4 V alloy. Remarkably, under the ultra-precision cutting scale, the detrimental effect of vibration texture caused by UEVC process on surface roughness should not be ignored. In this paper, the theoretical analysis and experimental studies on the influence of process parameters on the surface roughness were carried out for suppressing the adverse effects of vibration texture and improving the machined surface quality. The influence of vibration amplitudes in cutting and cutting depth directions, tool edge radius, cutting speed, and feed rate on the surface roughness was clarified. An ultra-precision machined surface of Ti-6Al-4 V alloy (Ra < 30 nm) was obtained, when the optimal process parameters were adopted. The research results indicated that the use of optimal process parameters can suppress the adverse effect of vibration texture on surface roughness and simultaneously retain the technical advantages of UEVC process.