微射流抛光机理仿真及实验研究

Simulation of Mechanism and Experimental Study in Micro Fluid Jet Polishing

为实现193nm投影物镜光学元件的超光滑加工,介绍了一种非接触式微射流超光滑表面加工方法,对该方法的材料去除特性和超光滑加工效果进行研究。首先,采用计算流体动力学理论对其材料去除机理进行了仿真研究,通过对微射流流场的压力、速度和表面剪切力的分析得到其去除函数形状与表面剪切力的分布相反,呈现W型。随后,采用正交法对各工艺参数对抛光效果的影响进行了综合分析,结果表明材料去除效率随入射速度和磨料浓度的增大而增大,随工作距离增大而减小,并且工作距离具有显著影响,为实验研究中工艺参数的选取提供了指导意义。最后,在自研的微射流抛光机床上对一平面熔石英进行了抛光实验,加工样件表面粗糙度均方根值由初始的1.02nm降为0.56nm。实验结果表明,微射流抛光技术可以用于光学元件的超光滑加工。

In order to realize ultra-smooth polishing for the optics of 193 nm projection lens, a non-contact micro fluid jet ultra-smooth surfaces polishing method is introduced, and the material removal mechanism and ultra-smooth polishing effect are investigated. First, the material removal mechanism is studied by fluid dynamics simulation, which indicates that the shape of the remove function takes on W type through the analysis of the flow flied. Then the influence of the technological parameters on the polishing effect is analyzed by using orthogonal test. It is shown that the material remove rate increases as the entrance velocity and abrasive concentration increase, and decreases as the work distance increases, and the work distance has a great effect, which gives some directions for the choice of technological parameters in the experiment study. At last, one fused silica flat optical element is polished, and the surface roughness （root-mean-square） of the sample is improved from initial 1.02 nm to final 0.56 nm. It is shown that the micro fluid jet polishing technology can be used for optical element ultra-smooth polishing.