Simulation And Experimental Study On Colloidal Jet Polishing Of Optical Coupling Nanoparticles Based On Rectangular Nozzles

The progress of science and technology always keeps pace with all kinds o f advanced manufacturing technology.The rapid advancement of science and technology also benefits from the constant pursuit of higher,faster and unknown.In recent years,with the development of electronic industry,biotechnology and aerospace technology,the demand for high-precision equipment,such as EUV lithography for chip manufacturing,higher resolution electron microscopy and farther and clearer space telescopes,has become more urgent.The research and manufacture of these equipments put forward higher requirements for the surface smoothness and surface shape accuracy of optical components.In addition,because hard and brittle materials are commonly used in the manufacture of optical elements,Therefore,it is required that the surface lattice structure of the work piece will not be spoiled after polishing,and there will be no stress damage.For these highly demanding optical elements,the traditional polishing method can not be used to process them,and new polishing technology of optical elements surface has been emerging as the times require.Ultraviolet-induction nanoparticle colloidal jet polishing technology is a recently proposed precision polishing method for optical elements.It uses nanoparticle colloids to adsorb materials on the surface of the workpiece u nder ultraviolet photocatalysis,and then uses the shearing action of colloidal jet on the surface of the workpiece to take away the surface materials that have adsorbed reactions,so as to achieve the deterministic removal of materials.The method can ach ieve nano-scale removal of the surface material of the workpiece,and there is no stress damage layer on the surface of the polished workpiece.Firstly,the experimental system of Ultraviolet-induction nanoparticle colloidal jet polishing was designed,and the optical-liquid coupling nozzle was the key point of the experimental system design.According to the structure of the jet nozzle and the basic characteristics of the jet,the prism rectangular optical-liquid coupling nozzle and the double jet rectangular optical-liquid coupling coupling nozzle were designed.By using the CFD software Fluent,the free turbulent jet model and the impinging jet model of the optical-liquid coupling nozzle were established and analysed.In addition,the conical rectangular optical-liquid coupling nozzle was compared with the prism rectangular optical-liquid coupling nozzle.The simulation results show that the flow field velocity distribution of the prism rectangular optical-liquid coupling nozzle is more uniform than that of the conical rectangular optical-liquid coupling nozzle,and the jet distance of the double-jet rectangular optical-liquid coupling nozzle should be less than the convergence area of the jet.Taguchi optimization method was used to optimize the size parameters of the optical-liquid coupling nozzle.The optimized optical-liquid coupling nozzle has larger initial jet velocity and more uniform jet distribution.The influence of polishing parameters on the flow field distribution on the workpiece surface was analyzed by variable control method.According to the optimized optical-liquid coupling nozzle and polishing parameters,the laboratory-made Ultraviolet-induction nanoparticle colloidal jet polishing experimental system was used to conduct a fixed-point jet polishing experiment on single crystal silicon to verify the effect of the Ultraviolet-induction nanoparticle colloidal jet polishing method on the surface material removal of the workpiece.The experimental results show that Ultraviolet-induction nanoparticle colloidal jet polishing can significantly improve the surface quality and reduce the surface roughness of the workpiece,and this polishing method will not produce mechanical scratches on the workpiece surface,and there is no residual stress on the workpiece surface,which can realize ultra-precision polishing of the workpiece surface.Provides an efficient and economical advanced optical manufacturing technology for non-destructive ultra-precision polishing of optical components.