光学元件磁性复合流体抛光特性研究

Magnetic compound fluid polishing characteristics of optical elements

采用磁性复合流体(MCF)对BK7玻璃进行定点抛光实验,对抛光斑进行三维模型重构,并对磁场空间分布进行仿真与实验分析,阐明抛光材料去除机理,确定材料去除率、表面粗糙度及硬度随抛光时间的变化规律,建立了材料去除量与磁通密度的关系曲线。实验结果表明:抛光形成的抛光斑表面轮廓为蝶形,其沿抛光轮轴向的截面轮廓呈“W”形;材料去除量与磁场强弱及抛光时间密切相关,抛光深度去除率最高可达553 nm/min;表面粗糙度随抛光时间的增加先上升后下降,MCF抛光可获得表面粗糙度Ra<6 nm的光滑表面,且粗糙度与硬度呈现一定的正相关关系。

The fixed-point polishing experiment of BK7 glass was carried out by using magnetic compound fluid(MCF).By building the three-dimensional model of polishing spot and simulating the spatial distribution of magnetic field,the material removal mechanism of MCF polishing was explained,and the variation of material removal rate,surface roughness and hardness with polishing time was determined.The relationship between material removal depth and magnetic flux density was established.The experimental results show that the surface profile of the polishing spot is"butterfly"shape and the cross-section profile along the axial direction of the polishing wheel is"W"shape.The material removal rate is closely related to magnetic field and polishing time,and the highest removal rate about polishing depth is 553 nm/min.The surface roughness first increases and then decreases with the increase of polishing time.The smooth surface with Ra roughness less than 6 nm can be produced by MCF polishing,and there is a positive correlation between roughness and hardness.