Study On The Key Technology Of Elastic Domain Low Defect Jet Polishing For Ultraviolet Fused Silica

Now,fused silica optical components are widely used.The material removal method is the main processing method,including grinding and polishing.The traditional grinding and polishing will produce mechanical crushing defects and pollution defects on the surface and subsurface of the workpiece,which will affect the application of fused silica optical components.Therefore,in order to improve the optical properties of fused silica components,a super smooth and low defect processing method is needed to further reduce or remove mechanical crushing defects and pollution defects on the workpiece surface.In this paper,the key technology of the elastic domain low defect jet polishing of the fused silica component is studied,combining the theory of elastic domain machining with abrasive jet polishing method.The main contents of this paper include the following three aspects:(1)Study on elastic domain jet polishing mechanism of fused silica.Firstly,the chemical removal process of jet polishing in elastic domain is modeled and simulated by molecular simulation software,and the feasibility of removing atomic material by elastic jet polishing is verified according to the system energy.Then,the relationship between the minimum mechanical energy with the particle size and the jet velocity is established,which provides theoretical guidance for the actual processing.Finally,the collision model of polishing particles and optical elements surface is improved.The boundary conditions of elastic collision and plastic collision are obtained.The elastic-plastic boundary processing theory is put forward,and the feasibility is verified by experiments.(2)Variation characteristics of elastic domain jet polishing mechanism of fused silica.Firstly,the fused silica samples,after dynamic acid etching in HF acid,are polished by elastic domain jet polishing.Then,the surface quality,photothermal intensity,laser damage threshold and surface contamination element content in the different removal depth were measured.The processing characteristics of fused silica components after dynamic etching of HF acid were obtained by elastic domain jet polishing.(3)Optimization on equipment and process of elastic domain jet polishing.Firstly,the existing circular jet polishing device is optimized.Then the array nozzle is designed by fluent flow field simulation,and the experimental verification is carried out.Finally,the polishing process was optimized by selecting different jet parameters,which further improved the efficiency of jet polishing.