Research Of Lapping And Polishing Characteristics For Fused Quartz Optical

Fused silica glass has good physical properties such as thermal stability,electrical insulation,dielectric properties,excellent transmittance,chemical stability,high temperature resistance and other optical properties,which was widely used in aerospace,inertial navigation,high-energy laser and other fields.Due to its high brittleness and high hardness,how to use ultra-precision machining technology to steadily reduce the surface quality of fused quartz to less than Ra 1 nm,and reducing and eliminating the surface / subsurface damage,residual stress after achined workpiece is the key technical issues for the performance of fused quartz glass elements.Magnetorheological finishing(MRF)technology,as an efficient flattened ultra-smooth finishing method,can achieve atomic-level finishing surface without subsurface damage after processing.In this paper,the ultra-precision machining technology of fused quartz optical glass is studied systematically.Firstly,the process of rough lapping and finishing of fused quartz glass is studied experimentally.The rough lapping of molten quartz glass is carried out by using cast iron plate by single factor experiment method,and the plane finishing of molten quartz glass is carried out by using synthetic copper plate.The influences of abrasive mass fraction,rotating speed of lapping disc,flow rate of lapping fluid and lapping time on the lapping characteristics of quartz glass were analyzed,and the smooth surface of Ra 4.11 nm was obtained by finishing.Secondly,based on the dynamic magnetic field cluster magnetorheological finishing method and device,the finishing experiment of the ground fused quartz glass is carried out by using a single factor experimental method.The finishing effect of fused quartz with different processing parameters was studied.Under the conditions of machining clearance 1.0 mm,swing distance ±25 mm,workpiece rotation speed 400 r/min,throwing disc speed 40 r/min,magnetic pole speed 20 r/min,swing speed 600mm/min,we had obtained an ultra-smooth and uniform surface with a surface roughness of Ra 0.32 nm was obtained with 3.2 μm carbonyl iron powder and 3 μm oxidized abrasive after machining 90 mim.Finally,the interaction between CeO2 and fused quartz glass in water-based magnetorheological finishing slurry was analyzed,and the material removal mechanism of cluster magnetorheological finishing with dynamic magnetic field was studied.The motion analysis and force of the workpiece in the dynamic magnetic field cluster magnetorheological finishing device were analyzed,and the material removal function model of the cluster magnetorheological finishing with dynamic magnetic field of fused quartz glass substrate was established,and the effectiveness of the model is verified by experiments.