Multi-physics analysis of the effect of the process parameters on the inter-layer geometry and surface topography of Laser Powder Bed Fusion-manufactured parts

Surface topography plays an important role in the quality of forming parts by the laser powder bed fusion (LPBF) process. This paper aims to analyze the effect of laser power in single-layer and multi-layer processing using 316L stainless steel. In particular, the novelty of this paper lies in considering the role of the recoater in inter-layer geometry and in analyzing the dynamics of the molten pool (MP) mechanism, which in turn affects the final surface topography. To this end, a multi-physics model incorporating powder bed formation, laser-MP interaction, and MP dynamics is developed. The results show that, for a constant scanning speed, peak and valleys become more pronounced when the laser power increases. Moreover, it is shown that, in the case of multi-layer process, at low laser power, the quality of surface topography does not change from one layer to the next. However, when the laser power is increased, the best surface topography is achieved by changing the laser power between layers. Our analysis provides theoretical and numerical guidance for the optimization of LPBF-3D-printed parts.