Stability Domain And Process Parameter Optimization For High Speed Milling Of The Thin Walled Box Workpiece

In the milling process of thin walled box workpiece,chatter between the tool and the workpiece in the milling process is easy to produce, which can reduce the surface machining quality and cutting efficiency. Existing research about the thin-walled box workpiece in high speed milling stability region and its process parameter optimization, ignore the influence of the helix angle of tool and workpiece modal time-varying on stability domain, resulting in using the optimized milling parameters in processing still exist chatter or can not achieve the goal of material removal rate maximization. This paper established high speed milling stability domain prediction model contains the helix angle of tool, and considering the change of the modal parameters of the workpiece to complete the optimization of milling parameters.In this paper, the dynamic model of the high speed milling of thin-walled workpiece considering the influence of tool helix angle on the contaction of tool and workpiece is established. In order to obtain the stability domain, the paper uses the regression analysis method to calculate the milling force coefficient based on the average milling force model, and the modal parameters of the workpiece are obtained by the modal experiment.In order to study the influence of the change of system parameters on the stability region, this paper uses the control variables method to study the variation trend of the lobe diagram of the radial milling depth, the natural frequency of the workpiece, the mass of the modal, the damping ratio and the number of different modes. The results show that the radial milling depth, workpiece natural frequency and modal mass and damping ratio changes will lead to the shift of the stability domain,and the stability region which is obtained by the first and second order modal parameters are overlap in some area. It is concluded that the influence of the change of the system parameters on the stability region can not be ignored.In milling process, the modal parameters of the workpiece change with the material removal. In this paper, based on the experimental data, the modal parameters of the workpiece with different wall thickness are analyzed by using ANSYS software. So that the milling stability lobe under different processing stages are researched.Finally, the cutting parameters are optimized by eatablishing the material removal rate as the optimization objective, the stability of the domain, the maximum allowable cutting power, cutting torque, spindle speed and the spindle speed to avoid the resonance band as the constraint condition.