Numerical Simulation Of Deposition Process Of Electroforming 3D Printing

Electroforming 3D printing is one of the most important electrodeposition-based additive manufacturing technologies.Compared with traditional manufacturing technology,it has some distinct advantages such as high dimensional accuracy and great process repeatability.However,the thickness non-uniformity of the deposited layer is a bottleneck problem for the further development of the technology.This problem seriously affects the accuracy,availability,and mechanical properties of the printed parts.The work aims to optimize the electroforming 3D printing process and improve the thickness uniformity of single-layer electrodeposition.In this paper,a multi-physical field models of coupling electrode reaction,inhibitor adsorption,fluid flow,material transport and sedimentary layer growth is established for the monolayer electrodeposition process,and trench deposition and triangular pattern deposition are studied by numerical solution.In view of the uneven sedimentation thickness of the trench,the evolution law of the morphology and thickness uniformity of the deposited layer with time was studied,and the main factors affecting the uniformity of the thickness of the deposited layer were analyzed based on the electrode reaction kinetics.Finally,the influence of the flow rate of the electrolyte body,the electrolyte conductivity,the cathode potential,the aspect ratio of the trench microstructure,and the concentration of the inhibitor body on the cross-sectional morphology of deposited layers and uniformity of their thickness were discussed.Aiming at the insufficient thickness of the deposited layer at the sharp corners of some graphics,the main causes were analyzed,the influence of the angle formed by the sidewall of the photoresist mask on surface contour of the deposited layer and uniformity of its thickness were discussed,and the measures to improve the insufficient thickness of the coating at the sharp corners were discussed.The results show that for trench deposition,the uneven distribution of reactive ion concentration and overpotential on the cathode surface is the main factor leading to uneven cross-sectional morphology and uneven thickness of the deposited layer,and the change in the cross-sectional morphology of deposited layers will have an adverse effect on the distribution of reactive ion concentration and overpotential on the cathode surface.The flow rate or conductivity of the electrolyte is too large or too small will reduce the thickness uniformity of the deposited layer,appropriately increase the cathode potential,increase the groove aspect ratio can improve the thickness uniformity of the deposited layer,and add a sufficient amount of inhibitors can also effectively improve the thickness uniformity of the deposited layer.For triangular pattern deposition,also at sharp corners,the difference in the concentration of reactive ions on the cathode surface will lead to excessive deposition at some sharp corners and insufficient deposition thickness at some sharp corners.The smaller the angle between the sidewalls of the mask,the smaller the thickness of the deposited layer at the sharp corners of the graph,and the smaller the thickness uniformity of the deposited layer.Simulation results show that adding sufficient amount of inhibitors and changing the flow direction to vertical direction are one of the effective measures to improve the uniformity of deposited layer thickness.