针对球头铣刀铣削薄板件的颤振稳定性进行分析,建立了包含前一次切削时留下圆弧形刀痕对刀工接触区域影响的三维多自由度铣削动力学模型；进而通过平均切削力法辨识得到切削力系数,通过锤击实验得到刀具和工件各处的模态参数,利用全离散法得到工件各点处的稳定性叶瓣图(stability lobe diagram,SLD)；最后进行了实验验证。理论计算和实验结果表明,工件各点处动力学特性的不同会导致各点处铣削稳定性预测结果不同,且在SLD中存在多个封闭的不稳定“孤岛”区域；不稳定“孤岛”区域与工件的模态刚度、模态频率、模态阻尼比有关。
In ball-end milling of thin-plate parts, the chatter stability is analyzed using a three-dimensional multiple degrees of freedom milling dynamic model. The influence of the circular arc area left by the previous cutting on the tool– workpiece contact area is considered. The cutting force coefficients are identified by the average cutting force method. The modal parameters of the tool and workpiece are obtained via the hammer experiment. The stability lobe diagram (SLD) at each measurement point of the workpiece is obtained using the full-discretization method. Both theoretical and experimental results show that the variations in the dynamic characteristics at each point of the workpiece will change the SLD. Moreover, several closed unstable "island" regions are detected in the SLD. The unstable "island" region is attributed to the modal stiffness, modal frequency, and modal damping ratio of the workpiece.
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