A comparative study of high-speed machining of Ti-6Al-4V and Inconel 718—part II: Effect of dynamic tool edge wear on cutting vibrations

Part II of the present study is a comparative study of high-speed machining of Ti-6Al-4V and Inconel 718, focusing on a comparison between the effects of dynamic tool edge wear on cutting vibrations. This paper describes in detail how cutting vibrations were measured and how vibration signals were processed using a wavelet packet transform technique. A total of 60 high-speed machining experiments were performed, covering a range of cutting speed and feed rate conditions. The experimental results show that tool edge wear has a complex effect on the cutting vibrations. The vibration amplitudes in high-speed machining of Ti-6Al-4V can be higher or lower than those in high-speed machining of Inconel 718, depending on the particular cutting speed and feed rate employed. Analysis of variance reveals that both the cutting speed and the feed rate always play a statistically significant role in affecting the vibration amplitudes in all three directions, i.e., the cutting speed direction, the feed rate direction, and the depth of cut direction. It is also revealed that in high-speed machining of Ti-6Al-4V, four significant wavelet packets (W30, W32, W33, and W36) exist, depending on the particular cutting conditions employed. In high-speed machining of Inconel 718, two significant wavelet packets (W32 and W33) exist, regardless of the cutting conditions employed. The significant wavelet packets identified in part II of the present study can be used as features to detect and monitor tool edge wear in high-speed machining.