Electropolishing and electropolishing-related allowances for powder bed selectively laser-melted Ti-6Al-4V alloy components

This study allowed the current density optimization for the efficient electropolishing of Ti-6Al-4V test coupons containing multiple surfaces, which were oriented with respect to the building platform under angles varying from 0 to 135°. It was shown that despite a large scatter in the as-built surface finish, ranging from Ra = 4 μm (0°) to Ra = 23 μm (135°), all the differently-oriented surfaces were polished down to a uniform roughness of Ra = 1-3 μm. This means that the higher the as-built surface roughness, the larger the quantity of the material needed to be removed during electropolishing in order to reach a uniform level of surface finish. Finally, thickness evolution measurements during finishing of the differently-oriented test coupons allowed us to establish the build orientation-dependent allowances for the electropolishing of selectively laser-melted Ti-6Al-4V parts.