Numerical Study of Localized Electrochemical Deposition for Micro Electrochemical Additive Manufacturing

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Abstract Electrochemical additive manufacturing (ECAM) is a novel non-thermal process capable of producing macro, micro and nanoscale metal parts by additive manufacturing. ECAM uses the principles of electrochemical deposition combined with the additive manufacturing technique to produce parts directly from three-dimensional computer models of the parts. The electrodeposition is localized by the use of ultra micro electrodes (UME) and low throwing power electrolytes, but plating is often seen accompanying the deposition, as the process is diffusion controlled near the UME, and kinetics controlled at the cathode away from the UME. In this study, the migration of the ionic species during deposition near the UME has been simulated and the diffusion characteristics were studied using numerical simulations to understand the effect of process parameters viz., tool size, inter-electrode gap, and voltage. The diffusion layer thickness and the width of the ion depletion region near the UME were studied under different voltage input characteristics. The findings of the simulation confirm the two different mechanisms of deposition, near and away from the UME. The findings reveal that the inter-electrode gap significantly affects the migration/diffusion controlled deposition process. Smaller gaps having higher current density but may result in inconsistent deposition due to the formation of a complete ion depletion region.