Investigation of Laser Polishing of Four Selective Laser Melting Alloy Samples

Abstract

Selective laser melting (SLM) is a layer by layer process of melting and solidifying of metal powders. The surface quality of the previous layer directly affects the uniformity of the next layer. If the surface roughness value of the previous layer is large, there is the possibility of not being able to complete the layering process such that the entire process has to be abandoned. At least, it may result in long term durability problem and the inhomogeneity, may even make the processed structure not be able to be predicted. In the present study, the ability of a fiber laser to in-situ polish the rough surfaces of four typical additive-manufactured alloys, namely, Ti6Al4V, AlSi10Mg, 316L and IN718 was demonstrated. The results revealed that the surface roughness of the as-received alloys could be reduced to about 3 μm through the application of the laser-polishing process, and the initial surfaces had roughness values of 8.80–16.64 μm. Meanwhile, for a given energy density, a higher laser power produced a laser-polishing effect that was often more obvious, with the surface roughness decreasing with an increase in the laser power. Further, the polishing strategy will be optimized by simulation in our following study.

Surface Roughness Considerations in Design for Additive Manufacturing - A Literature Review

“…Due to the inherent nature of the LPBF to produce parts with some level of surface roughness, efficient methods of post-processing are continuing to be developed. Currently to address the surface roughness issues of AM parts, post-processing methods such as abrasive blasting (Sagbas, 2020), shot peening (AlMangour and Yang, 2016) and laser polishing (Zhang et al, 2020) are utilised. The choice of post-processing method can have an impact on the properties of the outer layer of AM parts and part geometry, therefore careful consideration of method choice must be taken (Bouland et al, 2019;Kaynak and Tascioglu, 2020;Sagbas, 2020).…”

Laser polishing of additive manufactured Ti6Al4V alloy: a review

“…3. Zhang et al 50 studied the in-situ polishing of additive manufactured Ti6Al4V with a fiber laser. There was no need to clamp the components twice after 3D printing.…”

In-Situ Laser Polishing Additive Manufactured AlSi10Mg: Effect of Laser Polishing Strategy on Surface Morphology, Roughness and Microhardness

“…The effect of laser polishing is affected by many factors, such as laser energy density and polishing strategy. In our previous study, the effect of laser energy density on the laser polished surface roughness was investigated [ 21 ]. In this paper, a numerical model was established to study the rough surface evolution mechanism and complex hydrodynamic behavior in the molten pool during laser polishing with consideration of the phase transitions, gravity, recoil pressure, surface tension and Marangoni effect.…”