Numerical Simulation And Experimental Research On Machining Micro-dimple By Kerosene Submerged Jet Electrochemical Machining

Jet electrochemical machining(Jet-ECM)is a general term for a kind of electrochemical machining methods which use high-speed electrolytic jet as machining tool to realize material removal processing at specific position of the workpiece utilizing anode dissolution phenomenon.It not only has advantages of electrochemical machining,but also has characteristics of high processing speed,high degree of freedom of operation,good accessibility and high selectivity of material removal.Therefore,it has potential advantages in the field of microstructure processing.Due to the limitation of processing principle,there are problems of low machining accuracy and difficulty in controlling accuracy in Jet-ECM.Despite the tremendous efforts and excellent progress were made by the researchers,the machining accuracy of jet-ECM is still far away from the expectations of most industry.Submerged Jet-ECM is proposed in this paper in which nozzle,jet beam and workpiece are submerged in kerosene to enclose the outer wall and the end of metal nozzle,which is expected to restrain stray current and improve the machining accuracy of Jet-ECM.This paper was financially supported by Key Program of Science & Technology of Henan Province [No.172102210025] to conduct numerical simulation and experimental research on machining micro-dimple by kerosene submerged jet electrochemical machining.Details are as follows:(1)Numerical simulations were carried out to study the influence of kerosene and jet orientation(horizontal orientation and vertical orientation)on flow field distribution of machining micro-dimples in submerged Jet-ECM.It was found that the characteristics of the flow field distribution between the poles are basically similar in each machining phase(initial phase,shallow-dimple phase and deep-dimple phase),whether in horizontal or vertical orientation.The flow field distribution changes from flow film along machining surface in initial phase to umbrella-shaped distribution which tend to warp nozzle in deep-dimple phase.Compared with conventional jet(air),the diameter of electrolyte jet submerged in kerosene is smaller,the reflection phenomenon of electrolyte is reduced,and the contact extent and area between the reflected electrolyte and the nozzle outer wall is decreased.Compared with the vertical orientation,the thickness of flow film is increased,the discharge channel of electrolyte is smoother,the reflection of electrolyte is asymmetrical umbrella-shaped,and the contact with the outer wall of nozzle is reduced in horizontal orientation.Horizontally kerosene submerged jet is more conducive to electrochemical processing.(2)Experimental research of machining micro-dimples by submerged Jet-ECM with vertical orientation was carried out to analyze the effect of kerosene,shape and size of machining surface on machining accuracy.It showed that when the inner diameter of nozzle is small(170?m),the edge of micro-dimples machined in Kerosene has less stray dissolution,smaller the surface roughness,smaller diameter,deeper depth and larger aspect ratio than that of air in the voltage range matching with the nozzle-workpiece gap.When the inner diameter of nozzle becomes larger(340?m),the micro-dimple with high localization can be obtained within larger voltage range matching with the nozzleworkpiece gap.Compared with large plat surface machining area,the micro-dimples have better localization which machined on small plat surface and curve surface in kerosene.Kerosene is benefit to improve surface quality and processing accuracy.It has better machining results by using large nozzles or processing on small plat surface and curve surface because of the effect of shape and area of machining area.(3)Experimental research on vertically submerged Jet-ECM was conducted to investigate the impact of jet orientation on machining accuracy.It indicated that when the inner diameter of the nozzle is small(170?m)and the gap between the nozzle and the workpiece is 300?m,the micro-dimples machined on large plat surface have lager inclination on the edge,smaller surface roughness and smaller dimension in whole voltage range in horizontal orientation compared to vertical orientation.When the inner diameter of nozzle increases(340?m),the micro-dimples machined in horizontal orientation have smaller surface roughness,less stray dissolution at the edge,but larger dimension.With appropriate machining parameters(combination of low machining voltage and small machining gap or high machining voltage and large machining gap),horizontally submerged has better machining accuracy.Horizontal orientation is conductive to improve the surface quality and machining accuracy due to the effect of orientation.