Numerical Simulation And Process Study Of Electrochemical Machining Through Mask For Medical Micro-channel Mold

The microfluidic chip is widely used in the medical field because of its high efficiency,high degree of automation,easy to use,parallel analysis,short reaction time and low sample or reagent consumption and so on.Therefore,obtaining a good microfluidic mold is important because it can improve the processing efficiency of the chip and reduce processing costs.electrochemical machining through mask technology is a combination of photolithography and electrochemical etching.In the process,there is no electrode loss,no contact,no external force,no heat effect.And it can be applied to machine metal with high hardness and mold with complex pattern.In this paper,electrochemical machining(ECM)with mask of the medical microchannel mold(width:500 ± 10?m,depth 200 ± 10?m)is studied.The finite element model is established considering the flow field,anode and cathode product,temperature field and electric field.The numerical simulation of ECM with mask of microchannel is carried out and a series of experiments are couducted.The main contents and results are as follows:(1)Establishment of multiphysics finite element model.A micro-channel mold electrochemical machining through mask(ECMTM)as an object,the theoretical model of coupled fields was established after considering the influence of the flow field on the electric field through the intermediate physical quantity(hydrogen bubble rate,iron ion concentration and temperature)by COMSOL software.(2)According to the finite element model,the distribution of flow rate,electrolytic product,temperature and electric field in the electrolyte are analyzed.The effects of the inlet rate of the electrolyte on the bubble rate,the iron ion concentration and the temperature were discussed,and further influence by the above three on the conductivity and the uniformity of the channel size are discussed.During the process,the flow rate in the straight line segments is bigger than in the arc segments.The concentration and temperature of the electrolyte show an increasing trend from the inlet to the outlet,and the distribution of the micro flow channel is not uniform due to the flow velocity distribution.With the increase of electrolyte inlet speed,the parameters of each field change is small,the electrolyte conductivity is stable.The electric field affects the shape and machining velocity,and the flow field affects the uniformity of the entire channel.The experiment is conducted using the self-designed device.The contours of the grooves are measured with Keynes super-depth microscope,and arecompared with the simulation contours.Finally,the maximum error in depth direction is10.07?m.Percentage error is 5.03%.(3)Study on the process of ECM through anode mask of micro-channel.The range of current density,machining gap,electrolyte concentration and processing time are determined based on the simulation results.The influencing factors of geometric morphology and stray corrosion degree of SUS304 are studied by experiments.The experiments illustrate that: The scale of the groove increases as the current density,electrolyte concentration,processing time increases,and the machining gap decreases.The spurious corrosion degree of the groove is mainly related to the current density,and when the appropriate current density is selected,the degree of stray corrosion is the smallest.An average size of 498.48?m,208.92?m microchannel can be electrochemical machined using good parameters combination,which satisfies the technical requirements of microchannel mold.To extend the application of the parameters combination,an average size of 513.74?m,200.53?m microchannel are obtained by adjusting the processing time,which basically meet the requirements.A micro-channel mold electrochemical machining through mask(ECMTM)as an object,The influence of flow field parameters on forming uniformity was studied by numerical simulation.And the geometrical morphology and stray corrosion of micro-channel grooves were controlled by experiments.It provided theoretical and experimental basis for ECM through mask of complex pattern mold with large scale.