Mechanical Modeling And Stability Analysis In Milling Process

As a widely used metal machining means,milling has an indispensable role in aviation,aerospace,vehicles,mold production and other manufacturing industries.In the process of milling,milling chatter often occurs between the cutter and the workpiece,which leads to low cutter life,deterioration of surface quality and decrease of production efficiency.The mechanical model of milling process was established,the delay differential equation describing the dynamic model was solved,and the milling process parameters under stable machining conditions were obtained,so as to suppress chatter and achieve high quality and high efficiency milling,which provides guidance for practical engineering application.In this paper,from four perspectives of milling force,milling stability,milling experiment and milling simulation software design,the research work is as follows:(1)Based on the metal cutting mechanism,the geometric coordinate relationship and the milling thickness of the contact between the milling cutter and the machined object are analyzed.The micro element of the spiral cutting edge is discretized,the milling force model was established by axial integration of micro-element milling force.Analysis of milling force is affected by milling process parameters,milling cutter structure parameters;the mechanism of chatter generation in milling is elucidated,and the dynamic milling force model is established to provide theoretical basis for predicting milling stability.(2)The proposed numerical integration method to describe dynamic model of milling machining of delay differential equations,the method adopted in the period of delay in the numerical integration formula state transition matrix,based on the Floquet theory,comparative and state transition matrix eigenvalue and 1 size,the critical relationship between drawing spindle speed and depth of the milling stability lobes diagram;the effects of milling cutter modal parameters,milling force coefficient and the Angle between teeth on milling stability were investigated.(3)The interference effect of the milling cutter back face on the machined surface and the mechanism of damping effect are analyzed.The dynamic modeling of milling process considering regeneration effect,modal coupling and process damping effect was carried out,and the milling stability under different coupling factors was solved.It was revealed that the effects of modal coupling and process damping on milling stability could not be neglected at low spindle speed.The effect of damping coefficient on milling stability is discussed.The results show that the milling depth corresponding to spindle speed can be improved by decreasing the friction coefficient,increasing the compression coefficient and increasing the width of the cutter face.(4)In order to test the accuracy of the stability prediction results,the milling validation experiments were carried out based on the identification and acquisition experiments of milling force coefficients and modal parameters.A milling simulation software with simple interface and easy to operate is developed to predict the cutting force and milling stability,and to provide technical support for selecting appropriate machining parameters.