Analysis of tool chatter in turning operation for mass production

Abstract

Tool chatter is an ineluctable phenomenon often encountered during turning of metals on lathe In the last few decades researchers have tried to explore chatter phenomenon and also proposed various techniques to minimize it However while doing so they have overlooked the metal removal rate Tool chatter is a self originating phenomenon and is regenerative in nature Cutting tool leaves a wavy surface behind during the previous pass on work piece this further promotes regenerative chatter during the successive passes in turning process Regenerative chatter results in deep scratches on the machined surface thereby leading to poor surface finish and wear of cutting tool. In this thesis various chatter detection and prediction techniques proposed by the previous researchers have been reviewed to sum up the importance of research in the field of chatter From this meticulous review it has been inferred that there are various chatter detection and suppression processes suggested by researchers but their industrial acceptance is still very limited newlineIn the present work a new method has been proposed to detect, predict and quantify tool chatter in turning process This suggested methodology is based on wavelet transform statistical and artificial intelligence techniques. Wavelet transform has been used to preprocess the acquired raw chatter signals while statistical and artificial intelligence approaches have been applied to develop the mathematical models for chatter prediction In this thesis the effect of machining parameters depth of cut feed rate and spindle speed on chatter severity have been ascertained experimentally Experimentally recorded raw chatter signals have been denoised using wavelet transform WT in order to eliminate the unwanted noise inclusions Generally acquired chatter signals are contaminated with ambient noise. In order to ascertain the exact nature of chatter it is very essential to eliminate these noises present in raw signals Further in order to quantify the chatter severity a new parameter