Particle-assisted Through-mask Electrochemical Machining Of Metal Micro Holes Array Structure

Miniaturization and preciseness have gradually become a main development direction of modern industrial products.Metal micro holes array structures have been widely used in aviation,automobile,optics,electronics and other fields.Through mask electrochemical machining(TMECM)has advantages such as no material deformation,no tool loss,low machining cost and mass production,which make it has a broad application prospect in the processing of metal micro holes array structures.However,TMECM has the problem of poor localization,the machining accuracy and etching depth of micro holes are difficult to meet the machining demands.Therefore,in order to improve the locally removing ability of the TMECM,this paper proposed the method of particle-assisted through mask electrochemical machining(PA-TMECM).The research contents are as follows:The electrolytic products on the anode surface and the formation process of passivation film were analyzed by analyzing the electrode reaction of the TMECM.The effects of electrolytic products on TMECM was analyzed.A method of removing electrolytic products by PA-TMECM was proposed.The relationship between the removal amount of electrolytic products and the diameter,hardness,content and erosion velocity of particles in the process of particle erosion were analyzed.The semi-empirical formula between the resistance variation of electrolytic products and particle erosion parameters was deduced.Based on the above empirical formula,the simulation study of the micro hole structure in TMECM was carried out by COMSOL Multiphysics software.The effects of the erosion coefficient and erosion velocity of particles on the localization of the micro hole were studied respectively.The simulation results showed that with the increase of the particle erosion coefficient and erosion velocity,the resistance of the electrolytic product decreased continuously,the current density on the anode surface increased gradually,and the localization of the micro hole was improved obviously.In this paper,an experimental device of PA-TMECM was designed and fabricated.The experimental study of PA-TMECM was carried out.By comparing the experimental results of TMECM with and without particles,the etching factor EF has inc reased by 50.6%,and the locally etching ability of TMECM has significantly improved.Besides,the particle diameter,content and electrolyte flow of the added particles were optimized.When the diameter of micro holes were 100 ?m,the optimized particle size was 40 ?m,the optimized content was 6g/L,and the optimized electrolyte flow was 3000 ml/min.The locally removing ability of TMECM was improved,and the etching factor EF has increased from 1.66 to 3.52.The Electrochemical impedance test of electrolytic products was carried out.And the mechanism of the PA-TMECM was analyzed.The results showed that the anode surface resistance decreases by 45.04% in PA-TMECM.The simulation analysis on the erosion effect of particles was carried out.The simulation result showed that the resistance reduction of central area was larger than that of the lateral area in micro holes.The energy spectrum analysis of the element contents of electrolytic products was also conducted.The analysis result showed that the oxygen content of electrolytic products in central area decreased by50.56%,the oxygen content of electrolytic products in lateral area decreased by 13.89%.The mechanism of the PA-TMECM was analyzed.The electrolytic products on the anode surface were removed by continuous and high frequency impact of the particles.The erosion effect of the particles on the central area of the anode surface was obviously better than that on the lateral area.The PA-TMECM method restricted the lateral erosion and increased the etching depth of micro holes.Thus,the locally removing ability of TMEMM was improved.