| Chatter is an instability state commonly seen in machining operations involving material removal. Chatter has been identified as a detrimental problem that adversely impacts machine tool integrity, tool life, surface quality and dimensional precision of the workpiece. Machining dynamics along with machine tool chatter has long been studied. Nevertheless chatter remains a major problem in manufacturing industry.Firstly, this paper analyzed the problem and worked on it from a new perspective of rotor dynamics to establish the mathematical model of the chatter. Just as we know, the mass and the stiffness of the workpiece have been changed all the time because of the material removal in the turning operation, but the traditional model did not take these factors into account. In this article, based on the rotor dynamics and Lagrange equation, the chatter equation was established, in which the mass and stiffness factors are taken into account comparing with the traditional chatter equation, and the diversification was analyzed. After this equation was solved, we analyzed the effect of cutting depth, the feed rate and rotation speed on workpiece chatter in turning operation ,and also took the effect of moving load and variable mass and shape change of workpiece into account.Secondly, the chatter of workpiece is variable with different cutting parameters. The cutting force and displacement of vibration are measured in experiments with different cutting parameters, and the cutting force and deflection are analyzed when the chatter happened, and measured the effect of different parameters for vibration.Lastly, while the dimension of workpiece is variable during the turning operation, the variation of natural frequency of workpiece and mode are analyzed. In this paper, the mode shape and frequency shift are simulated during the turning operation in different locations and different depth of cuttings, and different workpieces with different radius.
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