Effect of laser ablation parameters on surface improvement of electron beam melted parts

Abstract

Electron beam melting (EBM) is one of the latest additive manufacturing technologies capable of producing near-net shape parts of Ti-6Al-4V alloy. In EBM, the parts are built from powder in a layer-by-layer fashion. The offshoot of this particular fabrication style is a poor quality surface. In the current work, laser ablation technique was employed to improve surface finish of EBM-produced parts. EBM surfaces were laser-treated by varying lamp intensity, pulse frequency, scan speed, and track displacement parameters. The surfaces were quantitatively assessed by surface roughness value Ra. Qualitative evaluation of the surfaces was done by viewing them under scanning electron microscope. Fluence, resulting from the combination of lamp intensity and pulse frequency factors, played a dominant role on the surface roughness. It was observed that the final finish was largely independent of the amount of material removed. In few of the cases, different laser settings produced distinct textures but the roughness values remained almost the same. How this peculiar characteristic can be exploited for tailoring the bio-implant surfaces is also addressed in this work.