高速精密车削中心主轴系统动态特性的研究

Experimental Investigation of the Spindle Dynamics in High-precision Machining Center

高速精密车削中心主轴系统的动态特性对高速精密加工的系统稳定性和加工精度会产生重要影响。应用试验方法研究了高速精密车削中心主轴系统在安装工件后动态特性的变化规律。研究表明在安装了不同的工件后主轴系统的固有频率随着工件悬臂长度而呈下降趋势,但在局部长度下当阻尼的增加超过刚度减少,则系统的动柔度反而下降;主轴夹紧力越大,其整体系统固有频率越高,而阻尼则呈下降的趋势;不同的工件材料在大悬臂长度时动态特性相差较大,但在小悬臂长度时的动态特性相差较小。

The machining quality and system stability of high-precision machining center are highly dependent on the dynamic performance of the entire machining system, which is determined by the interrelated dynamics of spindle structure and workpiece. In this paper, the dynamics of the combined spindle/workpiece system is investigated using impact testing techniques. The test results show that the general trend of the natural frequency is declined with the length of workpiece increasing. But when the damping increment outweighs the stiffness decrease, the system receptance is decreased. As the spindle champing force increasing, the system stiffness increases accordingly, but the change ratio is different in different work-piece , and higher spindle clamping force leads to reduce the modal damping of the system. As the work-piece length is shorten, the difference in dynamics of different workpiece materials is decreased.