Modeling and optimization of dual‐stage electropolishing (DSEP) for additively manufactured SS316L components

This article investigates the optimization of a novel dual‐stage electropolishing (DSEP) method for surface roughness improvement of additive‐manufactured SS316L. Additively manufactured components, due to various inevitable conditions, such as layer‐by‐layer printing, powder adhesion to the molten pool, rapid heating and cooling, etc., lead to high surface roughness and other defects. These defects are prominent in complex components. Post‐processing of metal additive‐manufactured components remains challenging, especially for complex and miniature components. Electropolishing (EP) is an advanced machining technique to mitigate metallic components’ surface roughness and enhance their corrosion resistance as well. However, conventional electropolishing is effective when the surface roughness is low, as the material removal rate is slow. This current work is motivated by the need to improve the material removal rate of conventional electropolishing as well as the surface quality of additively manufactured SS316L components. In the first stage of dual‐stage electropolishing, high voltage is supplied compared to the limited current plateau region (LCPR) to dissolve defects like partial melts and attached particles, and in the second stage, the potential difference is supplied in the limited current plateau region for further smoothening. Response surface methodology (RSM) and analysis of variance (ANOVA) are used to optimize parameters like first‐stage voltage (V 1 ) and process durations (T 1 ) and (T 2 ). Dual‐stage electropolishing reduces surface roughness by approximately 69 % compared to 49 % by conventional electropolishing. The energy‐dispersive x‐ray spectroscopy (EDS) analysis manifested increased iron and chromium content in the final polished sample. Additionally, potentiodynamic polarization tests confirmed a significant improvement in corrosion resistance.