Electro-chemical polishing: a technique for surface improvements after laser milling

Electro-chemical polishing is a process of improving micro smoothness, micro topology, and material brightness by anodic dissolving of the substrate in an electrolyte with an external source of electricity. The resulting surface improvements depend on the uniformity of the material microstructure, the lack of surface inclusions, and the consistency of the surface finish all over the target area. In contrast, laser milled structures are mostly concave features; their roughness is usually higher than that achieved on the other surfaces of the component, and also there is a significant presence of foreign or recast particles on them. Thus, it is important to investigate systematically the effects of electro-chemical polishing on microstructures machined by laser milling. The paper discusses the effects of electro-chemical polishing on the surface finish of laser milled features. Although ECP displayed some limitations when polishing micro features, it still managed to achieve almost 30% improvements in comparison to the initial roughness after laser milling. Another benefit is that the process also improves the edge quality of the laser machined structures by removing the burrs.