微小振动影响超精密非球面加工精度的研究

INFLUENCE OF CHATTER VIBRATION ON THE ULTRAPRECISION MACHINING ACCURACY OF ASPHERIC SURFACE

超精密磨削已广泛应用于轴对称非球面光学元件及硬脆材料的加工 ,加工过程中砂轮的不平衡量和机床主轴引起的振动直接影响工件表面精度及粗糙度。为了适应非球面工件超精密加工的要求 ,本文通过分析加工过程中产生的振动现象 ,建立磨削中振动引起工件表面轮廓误差的数学模型 ,研究主轴转速变化及磨削加工参数对工件表面精度的影响 ;通过建立工件与砂轮之间的运动关系 ,得出砂轮的振幅、频率及加工速度的变化对工件表面精度的影响条件。研究结果表明 :选择合理的加工参数能降低工件表面波纹度 。

Grinding technology of axisymmetric aspherical workpiece has attracted great attention in the precision manufacturing field, and it is widely used in machining optical lens and hard brittle materials. During the machining process, the unbalance of wheel and vibration of spindle have great impact on workpiece accuracy and roughness. To analyze the occurred vibration, this paper established a mathematical model describing how vibration led to the error of workpiece surface profile, and studied the influence parameters of variation of wheel and spindle on the workpiece surface. By setting up motion correlation between workpiece and wheel, the conditions of how workpiece surface quality was affected by the vibration amplitude, frequency and machining speed were discovered. Research results showed that, with appropriate machining parameters, the ground surface waviness can be decreased.