Study On The Dynamic Modeling And Simulation Of Ball-end Milling Process

Ball-end Milling technology has been widely used in machinery manufacturing due to its advantages in high efficiency and accuracy. But in practical production it does not give full play to its superior performance as the result of the lack of in-depth research on the milling mechanism and process. In addition, the cyclical vibration that caused by the blade in the processing which will leave ripples in the processing surface, reduces the processing quality. Thus it is of vital importance in improving the processing technology, the efficiency of the milling process and the quality for us to study the mechanism of milling process and stability. This paper takes the ball-end milling as the research object, a deeper analysis on the milling force and stability in the milling process is made. The main content is summarized as follows:Firstly, the geometry structure of the ball-end mill is analysised. At the same time, the equations of spherical milling spiral geometry is established. The calculation expression of the uncutting thickness is deduced on the basis of the changing rule of the cutter maching position. In view of the two kinds of processing methods which includes up milling and down milling, the relational expression between the axial cutting position and the cutting angle is derived. The mathematical model of the micro milling force is made based on the model of the transient rigid force. then the whole milling force model is established.Secondly, the Matlab language is written based on the milling force method and the least squares method, the identification of the cutting force coefficient is made with the test data. The simulation software for the milling forces is developed. The influence of the axial milling depth and each tooth feeding on the milling force is studied through numerical simulation.Thirdly, the dynamic milling force model of regenerative chatter state is established based on the regenerative chatter mechanism. The stability criterion of the high speed milling and the calculated formula of ultimate axial milling depth is deduced according to the Lyapunov stability theory. The influence of the kinetics parameters of milling system and the cutting tool geometry parameters on the flutter stability domain is studied through the stability limit diagram method. The simulation result shows that the stability of the cutting process will strengthened with the increase of the stiffness, damping and natural frequency.Fourthly, the dynamics model of the ball-end milling system is established.The Matlab language simulation program for the ball-end milling system is developed by using the fourth-order runge-kutta algorithm and the simulation of the milling force and the vibration displacement is realized. Four points which lie in the steady and unsteady regions in the chatter stability lobes is studied by simulation method and the validity of the results of the flutter theory research is proved...