Metal additive manufacturing (AM), owing to its layer-by-layer nature, produces components with detrimental surface quality, impeding their performance and integration into larger systems. To address such challenges, this study presents a novel sustainable electro mechano-chemical polishing (SEMC) polishing technique that utilizes polishing media containing cationic exchange resin particles to enhance the surface quality of metal AM parts. Laser powder direct energy deposition (LP-DED) technique was employed to fabricate nitrogen-strengthened austenitic stainless (Nitronic-60) steel, which was subsequently polished using the SEMC polishing technique. Two distinct formulations of polishing media were utilized for polishing the Nitronic-60 steel samples, consequently the resulting 3D surface topography and surface morphologies were analyzed using non-contact surface profilometry and scanning electron microscopy (SEM), respectively. The study focuses on the amplitude surface roughness parameters, including arithmetical mean height (Sa), root mean square height (Sq), skewness (Ssk), and kurtosis (Sku). Measurements were conducted before and after SEMC polishing, revealing 62 % and 68 % reductions for Sa and Sq on the top surface and 73 % and 79 % on the side surface, respectively. Further, elemental analysis confirmed the removal of partially melted powders, manganese and silicon-based oxide inclusions formed on the as-built surface, indicating the effectiveness of SEMC polishing. These findings demonstrate a significant improvement in the surface quality of Nitronic-60 steel, validating the efficacy of SEMC polishing in enhancing the surface quality of AM parts in an environmentally friendly and efficient manner.
