| With the development of the human society industrialization degree,the consumption of traditional energy such as oil and gas is increasing,energy saving and emission reduction has become a growing concern.Data show that a large part of energy consumption comes from mechanical wear caused by friction loss,about 30%of the energy consumption in industrialized countries comes from friction and wear,and in all the failed mechanical parts,the ratio of friction failure to other failure forms is as high as 4:1.Therefore,it has become an important issue in energy conservation to improve lubrication performance,reduce friction and wear and prolong the service life of mechanical parts.In the aspect of improving the surface performance of the mechanical parts and improving the utilization ratio of energy,the traditional tribology point of view is that the smoother and smoother the surface of the friction pair,the better the tribological performance.However,with the recent research,more and more data show that the non smooth surface with some regular micro structures,such as convex concave,is more excellent.In order to better express the surface texture(Surface texture)concept,refers to the processing technology of processing by certain a certain size and distribution of pits and dents or convex patterns such as lattice friction surface.Due to the high performance requirement of the friction pairs,the mechanical parts are made of difficult cutting material,meanwhile the traditional processing method are difficult to meet the processing requirements.Electrochemical machining has the advantages of no cutting force cutting heat,no deformation of work piece,even with high hardness and high strength material,very suitable for machining micro-dimple array.In order to solve the machining problem of surface texture of mechanical parts,make full use of the advantages of electrochemical machining,In this paper,the method of mask electrochemical machining is put forward to process the micro-dimple array on the surface of work piece,to obtain micro-dimple with micron level diameter and depth.The main research contents can be divided into the following aspects:(1)The test scheme of micro-dimple array mask electrochemical machining is designed,and the whole test equipment is built.Including the design and manufacture of the cathode of the tool,the selection of the processing power and the circulating pump of the electrolyte,the disposition of the electrolyte and the determination of the relative conductivity.The fixture structure is optimized according to the simulation results of flow field.(2)The COMSOL Multiphisics software is used to simulate the process of micro-dimple forming in a single micro-dimple,and the 3D simulation of the micro pits array is carried out.The mathematical model of coupling flow field,electric field,temperature field and physical field of mobile grid,analyzes the different processing time and processing voltage on the influence of micro pit forming;analysis of the temperature distribution in machining gap;analyzes the current edge effect of holes and improve the array size;and prove the feasibility of the scheme through preliminary test the pre experiment,accuracy of the pre-experiment results Validate the simulation results.(3)The fabrication of insulating mask layer on the surface of work piece is made.The method comprises the following steps:pretreatment of the surface of the work piece,the coating and drying of the liquid SU-8 photoresist,the development of the ultraviolet ray exposure and the development of the mask layer.(4)The process experiment of mask electrochemical machining of micro pits was carried out.The influence of different experimental parameters on the machining results is studied.The optimal experimental parameters are selected,and the other shaped dimple are manufactured. |
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