Surface Finishing of Additive Manufactured Titanium Alloy by Plasma Electrolytic Polishing Without Pretreatments

The advent of the additive manufacturing of Ti-6Al-4V (Ti64) alloys has facilitated the production of complex geometries for various industrial applications. Nevertheless, the inherent surface roughness of selective laser melting (SLM)-produced parts remains a critical limitation, adversely affecting fatigue life, wear, corrosion, and compliance with stringent surface quality standards, for example those required in hygienic applications. Conventional post-processing methodologies, encompassing grinding and electropolishing, are frequently multi-stage, labor-intensive, and reliant on hazardous electrolytes, which thus limits their use for certain applications. In this study, plasma electrolytic polishing (PEP) was evaluated as a single-step finishing process for 3D-printed Ti64 components. The findings indicate that PEP efficiently diminished surface roughness from initial values of approximately 9-10 µm to as low as 0.38-0.5 µm within a time frame of 15-20 min, depending on the initial surface condition. These outcomes meet hygienic surface requirements while ensuring the use of environmentally compatible electrolytes. The findings establish PEP as a non-mechanical, efficient, and scalable additive-manufacturing post-processing strategy. It has the capacity to supersede conventional multi-stage workflows and offer substantial reductions in cost, time, and environmental impact.