Effect of processing parameters on overhanging channel forming quality during laser powder bed fusion of AlSi10Mg

During the process of laser powder bed fusion (LPBF), the inclusion of support structure is often necessary for overhanging channel specimens, which significantly limits the applicability of complex designs. This study evaluates the influence of various process parameters on the forming quality of overhanging channel specimens without support structures, considering overhanging angles of 30° and 60°. A design of experiment (DoE) methodology was employed to investigate the correlation between forming quality and LPBF process parameters, including infill laser power, infill scanning angle, scanning angle, contour laser power, and contour scanning angle. The roundness and morphology of the overhanging channels were thoroughly examined. The results revealed that the influence of process parameters on roundness varied with different overhanging angles. In comparison to contour process parameters, infill process parameters exhibited a more significant effect on the forming quality of the overhanging channel. At a 30° overhanging angle, scanning angle emerged as the most influential parameter. As the overhanging angle increased to 60°, infill laser power had a notably stronger influence than other process parameters. The study also determined that the interactions between infill laser power and scanning speed, and between contour laser power and scanning speed, had negligible effects on the forming quality for the overhanging channel specimens. The minimum roundness values observed for the overhanging channels were 0.13 μm and 0.38 μm at 30° and 60° overhanging angles, respectively.