Reseach On Chatter Of Slender Shaft In Turning Based On Cutting Width

Slender shaft parts is widely used in national defense, transportation, agriculture and other fields, which play an important role in the connection and transmission of the machine. However cutting system generates a chatter in turning of slender shaft, which seriously affects the machining accuracy of the workpiece and the surface quality. Not only the efficiency of the machine is reduced, but also the cutting tool is wear, tool parts is damaged. It makes a difficult problem to the engineers for a long time, which in the machining of slender shaft. With the increasingly higher demand of accuracy, it is a significant that research on chatter of slender shaft in the cutting process and control.Firstly, the chatter mechanism of slender shaft is analyzed in this paper. The mathematical model of regenerative chatter is established, which caused by the delaying feedback of displacement. Then the stable lobe graph is obtained between the limit cutting width and speed, though establishing the liner differential equation and deriving the critical condition of chatter.Through the simulation model of cutting chatter system that designed by Simulink, which was simulated in time domain, it comes out the variation of amplitude in different cutting width, overlapping coefficient, frequency of the cutting system. And it validates the correctness of theory analysis. Considering the limitation of linear theory, the cutting chatter by nonlinear theory in slender shaft is analyzed, which has a new understanding of situation after the chatter instability.On the basis of this, a new proces method is put forward, which uses symmetric twin cutter in turning, The workpiece is considered as a rigid, ignored the dynamic changes, The vibration model of dual-tools turning is established with single degree of freedom. Using the simulation method of time domain, compared with ordinary lathe, it concludes that the method of dual-tools turning is better, which the chatter is more stability and the amplitude is smaller.Finally, a suppression method of cutting chatter is discussed based on intelligent control strategy. The principle and design of fuzzy control is introduced, the plan of the control system is determined, Then a simulation model based on fuzzy control by constant cutting force is designed. And the variation conditions of cutting force is got, the response speed is faster, it is closer to the the force pre designed. The analysis results show that using the fuzzy control has a good robustness for cutting chatter stability, which can reduce vibration and improve the quality in the process of slender shaft.