Analytical study of the melt pool distortion in the Laser Powder Bed Fusion Process caused by the angle of incidence of the laser and its effect on the surface finish of the part

Abstract

One of the factors that most affects surface roughness is the angle of incidence of the laser with respect to the platform, which varies across the platform. However, to make the L-PBF process a competitive technology, several parts must be manufactured on the same platform, using maximum building volume. Nevertheless, due to this angle of incidence, even if identical parameters and geometries are used, the surface finish of the parts varies considerably depending on the positioning of the part on the platform. Throughout this work, the effect that this angle of incidence has on the surface of parts manufactured in the different positions of the platform is presented. For this purpose, first the angle of incidence on the whole platform was determined. Then, based on these results, the distortion of the melt pool was analyzed analytically, with the aim of relating the poor surface finish, seen by different technologies such as infinite focus microscope or SEM, with the distortion of the melt pool generated by the angle of incidence.

Effect of powder particle size distribution on the surface finish of components manufactured by laser powder bed fusion

“…Due to this positioning, the laser beam is perpendicular to the platform only in the central part, as the studies carried out by Rott et al [8] demonstrated. While on the parts located far from the centre of the platform, the laser beam is not completely perpendicular [11,14] to the platform so, it generates distortion in the melt pool that affects the roughness of the final part [15].…”