Effect Of Chatter On Machining Accuracy In Cutting Process Of Vertical Machining Center

Milling is a very important manufacturing method,which is more and more used in various metal manufacturing processes.In milling process,chatter is a major factor affecting the instability of machine tools.It is a kind of mutual vibration between tool and workpiece under self-excitation,which seriously affects the machining stability of machine tool,accelerates the wear and tear of tool,and reduces the service life of machine tool and tool.Therefore,it is particularly important to analyze and suppress chatter stability in milling process.In this paper,the process damping in milling process is taken as the research object,and a milling dynamic model considering process damping is established.The stability of milling chatter is analyzed.The main research contents are as follows:Firstly,the mechanism of process damping is deeply studied,and the theoretical calculation model of process damping force in milling process is given.Based on the classical milling dynamics,a milling dynamic model considering process damping is established.Then,the three-dimensional model of tool and workpiece is established,and the process of milling workpiece is simulated by Deform finite element simulation software.The average milling force in X and Y directions is obtained,and then the milling force coefficient is calculated by using the theory knowledge of average milling force coefficient.The basic principle of modal experiment is analyzed.The directional frequency response functions of tool X and Y are obtained by modal hammering experiment,and the first-order modal parameters of tool X and Y are obtained.Finally,the milling stability lobe diagram considering process damping is drawn by using MATLAB simulation.The simulation results show that the process damping has a great influence on the stability lobe diagram in the low-speed region,and the stability region increases significantly.In the high-speed region,the stability lobe diagram is basically the same.The simulation results are verified by milling vibration experiments.Finally,the influence of tool parameters on milling stability region is analyzed.