Feasibility Study On Electrochemical Polishing Of Tungsten Mold For Molding Of Microfluidic Chips

Microfluidic chip is an important scientific component in the 21 st century.It is widely used in important scientific fields such as protein crystallization,single cell collection,drug development,and organic synthesis.In the manufacturing process of glass-based micro-channel chips,glass molding is an efficient and precise production process of glass parts,which can realize mass production of micro-channel chips.In order to mold the glass parts that meet the industrial requirements,the mechanically processed molds need to be polished.In the manufacturing process of the mold,the time required for the polishing of the mold accounts for a large proportion of the production time of the mold.Therefore,reducing the surface roughness of the mold and improving the polishing efficiency of the mold have important research significance.This paper uses tungsten as the glass mold material to develop the feasibility study of electrochemical polishing of tungsten molds for glass-based microfluidic chips.The polishing of tungsten planar blocks has been studied by scholars,but there are few reports on the polishing of three-dimensional structure molds.Therefore,this paper conducts a feasibility study on the polishing of molds with three-dimensional characteristics.In this paper,the traditional fully immersed electrochemical polishing experiment was carried out,and the surface morphology,roughness,dimensional change and other parameters of the tungsten mold during the polishing process were evaluated by various testing equipment.In addition,a tungsten metal polishing experiment using a sulfuric acid-methanol mixed solution as an electrolyte was carried out,and morphological changes were observed.The experimental results show that when the selected electrolyte is a 0.5% Na OH solution,after polishing for 30 min,it is observed by scanning electron microscope and white light interferometer that the scratches left by mechanical processing are effectively removed.After 1 h After polishing,the roughness is greatly improved,reaching the level of Sa 30-60 nm,and the surface roughness can be reduced to Sa 15 nm after 3 h.However,the laser confocal shape measurement microscope found that the removal amount of different regions of the mold was different,and the difference between the highest change rate and the lowest change rate was as high as 19.3%.In view of the problems of uneven current density and large electrolyte consumption in the traditional fully immersed electrochemical polishing method,this paper proposes a layered solution dynamic electrochemical polishing process based on a small amount of electrolyte,which can achieve a large area with a small amount of electrolyte Tungsten alloy samples are polished efficiently and can make the dimensional change of different areas basically the same.In the process optimization experiment,static electrochemical polishing was carried out.The experiment found that high voltage can make the anode surface smooth.In addition,the experiment also found that continuous time polishing has a better polishing effect than segmented time polishing.In this paper,the dynamic polishing experiment is also explored,and it is found that when the sample movement rate is 40 ?m/s,a better polishing effect can be obtained.When this process is applied to the polishing of molds,it is found that after 10 electrochemical polishing,the surface roughness of the mold can be reduced from the level of Sa 200 nm to within Sa 10 nm,the rate of height change is within 2%,and the rate of width change is 9 There is no obvious difference in the rate of change in different regions.At the end of the article,through the observation of the change of the morphology of the tungsten alloy sample during the polishing process,it is found that the polishing of tungsten metal is a smooth process for the growth of the etch pits.