基于机床动态特性的超精密飞切加工表面波纹机理解析

摘要

Ultra-precision flycutting is widely used to machine soft and brittle plane optical elements,and the controllability of micro surface texture affects the performance of the element directly. The multi-scale wavelet decomposition was used to detect the wave feature of the optical element machined by flycutting machine tool,and the frequency and percent of the waves were achieved.The relevant modals of those waves were found by the finite element analysis and the response test of the spindle system.Particularly,online vibration test and machining experiments were conducted to verify the factor bringing about the micro surface texture on the element.The results show that the micro surface texture at a space period of 1 7 mm is the most prominent and will make worse observably the accuracy and application of the element,which is caused by the response of the spindle system during the machining process.In addition,modifying the structure of spindle system can make a difference on the amplitude and frequency of the wave.%采用超精密飞切加工技术可获得软脆性平面光学元件的最终表面，而元件表面微观形貌的加工可控性对于光学元件使用性能有直接影响。首先运用多尺度小波分解方法，对飞切机床的加工表面波纹进行了特征提取，得到了工件表面波纹的频率组成及占比；然后通过对机床主轴系统的有限元分析，结合冲击振动测试，找到了与工件表面波纹对应的模态；最后通过对机床的在线振动测试及加工实验进一步明确了飞切加工表面微波纹的成因。结果表明：表面波纹在17 mm 左右的空间周期上存在最大的分量，显著影响光学元件的精度和使用效果，该波纹由主轴系统在间断切削的冲击响应所引起，可以通过改变主轴结构实现波纹频率和幅值的控制。