Estimation of stable cutting zone in turning based on empirical mode decomposition and statistical approach

Abstract

Analysis and suppression of tool chatter are essential for maintaining the high-performance level and enhancing the useful life of machinery. Despite the immense work done within this domain, still many aspects related to regenerative chatter remain unexplored. Researchers had suggested various techniques to explore the chatter mechanism based on feature extraction of experimentally recorded chatter signals. However, the effect of background noise and other disturbances on chatter signals has been overlooked by these researchers. To obtain the exact effect of cutting parameters on chatter signals, it is essential to sieve out the noise contents from these signals. This aforesaid fact motivated the present research work. In the present study, acoustic chatter signals have been recorded using a microphone, by performing experiments on CNC trainer lathe. The recorded chatter signals have been pre-processed using empirical mode decomposition technique. Thereafter, the obtained intrinsic mode functions have been subsequently analyzed to identify the most dominating mode that is pertaining to tool chatter. Further, a new parameter named as chatter index and material removal rate (MRR) have been evaluated as responses to estimate the stable cutting zone at different cutting conditions. Moreover, mathematical models have been developed using response surface methodology, in order to establish the dependency of tool chatter and MRR on machining parameters.