Research On Numerical Simulation And Prcocess Parameters Of Three-phase Swirl Polishing

Monocrystalline silicon sheet,K9 optical glass and other electronic information materials are widely used in the electronic industry,intelligent equipment control system and other fields,the surface quality of these materials to a great extent affects the stability,service life,performance of semiconductor and other core components.The traditional low pressure soft abrasive flow polishing can produce a highly smooth surface,and has a good adaptability to the processing surface,but its processing efficiency is very low.In view of the advantages of soft abrasive flow processing,it is of great significance in the field of electronic information materials processing.Aiming at the above problems,a three phase abrasive flow polishing method for cavitation rotating abrasive flow polishing(CRAFP)of venturi tube structure is designed,and adopts taguchi method,BP neural network and genetic algorithm to study and optimize the process parameters.Firstly,the suitable turbulence model and multiphase flow model are selected based on the characteristics of three phase abrasive flow,and then the flow channel model was meshed,the relevant numerical simulation analysis was performed;Then the process parameters are studied by taguchi method,the roughness prediction function model is established by BP neural network,and the optimal solution is found by genetic algorithm;Finally,the experimental platform of machining is built and the relevant experimental verification is carried out.The specific content of this article is as follows:(1)Aiming at the problem that the traditional low pressure soft abrasive flow polishing method has low processing efficiency for hard and brittle materials and the poor polishing results caused by improper process parameters,combining the latest research advances at home and abroad on methods for processing hard and brittle materials and optimizing process parameters,a novel CRAPF method is proposed,and the process parameters are researched and optimized by using Taguchi method,BP neural network,and genetic algorithm.(2)Based on the analysis of the near-wall flow field characteristics during three-phase abrasive particle flow processing,the Realizable turbulence model and the Mixture multiphase flow model were selected through analysis and summary;At the same time,the motion characteristics of the bubbles during the cavitation process and the mechanism of the collapse of the cavitation were analyzed,and the Zwart-Gerber-Belamri cavitation model was selected;After that,the force of a single abrasive particle in the flow field is analyzed,and the micro-cutting mechanism of the workpiece surface is further analyzed.(3)Based on the design and processing equipment,the cavitation-assisted abrasive particle flow vortex machining principle was analyzed,and then the flow channel model was meshed and the grid independence was verified;The relationship between inlet air pressure and cavitation intensity was analyzed through numerical simulation.It was concluded that within a certain range,increasing the inlet air pressure would increase the cavitation intensity,and numerical simulations of the polishing flow field with and without cavitation are performed.(4)Taguchi experiments were performed on five factors affecting the surface roughness of the workpiece,including the particle size,concentration,number of nozzles,distance from the workpiece surface to the polishing tool,and inlet pressure.Through analysis,the degree of influence of these five factors on the roughness is: distance,inlet pressure,abrasive particle size,concentration,and number of nozzles.Then a BP neural network was used to establish a roughness function prediction model between these five factors and roughness.Finally,the genetic algorithm was used to find the optimal combination of process parameters: 0.7um abrasive particles,a concentration of 12%,6 nozzles,a distance of 0.8mm,and an inlet pressure of 0.45 Mpa.Under these conditions,silicon wafers are polished based on the CRAPF method,Its surface roughness was reduced from about Ra50.0nm to final Ra3.50 nm,and the surface roughness improved by about 94.70%.(5)An experimental platform for abrasive particle flow processing was set up,and a comparative experiment between the traditional soft abrasive particle flow processing method and the CRAFP method was performed,and the morphology of the workpiece surface after polishing was compared with the rate of decrease in roughness over time.It is concluded that the three-phase abrasive particle flow processing method using CRAFP can not only improve the polishing efficiency of the workpiece,but also obtain a higher surface quality of the workpiece.The finishing process experiment was carried out using the optimized process parameter group after the process parameters were optimized,and the changes of the workpiece surface during the machining process were observed.