熔石英玻璃高效低缺陷磁辅助抛光

Magnetic-assisted polishing of fused silica optics with high efficiency and low defects

为了实现熔石英元件的高效低缺陷加工,研究了基于磁辅助抛光技术的元件材料去除特性和表面质量形成机制。采用不同抛光间隙和不同铁粉体积比的磁性抛光液对研磨后的熔石英元件进行磁辅助抛光,并对元件材料去除率、抛光斑轮廓、表面粗糙度和透过率进行评价,结合空间磁感应强度仿真和抛光压力分析,确定加工参数对元件加工效率和表面质量的影响规律。结果表明:材料深度去除率随空间磁感应强度的增强呈幂函数上升且随抛光液中铁粉体积比增加而显著提升,低空间磁场强度和低铁粉体积比的抛光液有利于促进以化学去除为主的磁辅助弹性抛光从而获得光洁表面。小抛光间隙(0.5 mm)及高铁粉体积比(14.18%)的抛光液可实现最大材料深度去除率0.4392μm/min和体积去除率1.49×10^(-4) mm^(3)/min,大抛光间隙(1.5 mm)及低铁粉体积比(9.93%)的抛光液能够获得粗糙度R_(a)低至8.1 nm的光滑表面。

To achieve high-efficiency and low-defect machining of fused silica optics,the material removal characteristics and surface quality formation mechanism based on magnetically assisted polishing technology were studied.Magnetic polishing fluid with different degrees of polishing clearance and different volume ratios of iron powders was used to conduct magnetically assisted polishing of lapped fused silica optics.The material removal rate,profile of polished spots,surface roughness,and transmittance of sam ples were evaluated,and the effects of the processing parameters on processing efficiency and surface quality were determined by combining a spatial magnetic flux intensity simulation and polishing pressure analysis.Results show that the material depth removal rate increases as a power function with the magnetic flux intensity and rises significantly with the volume ratio of iron powders in the polishing fluid.In addition,polishing fluid with a low spatial magnetic field intensity and low volume ratio of iron powders can facilitate material removal in the elastic domain,resulting in a smooth surface.A small polishing clearance of 0.5 mm and high iron powder volume ratio of 14.18%in the polishing fluid can obtain maximum depth removal and volume removal rates of 0.4392μm/min and 1.49×10^(-4)mm^(3)/min,respectively.A large polishing gap of 1.5 mm and a low volume ratio of iron powders of 9.93%generates a smooth surface with R_(a) roughness as low as 8.1 nm.