Investigation of surface shot blasting of AlSi10Mg and Ti6Al4V components produced by powder bed fusion technologies

Metal additive manufacturing (AM) is constantly expanding thanks to the freedom to create complex, light, and high performing geometries within the limits of the processing itself. As-built AM parts, especially when using powder bed fusion (PBF) processes, exhibit surface imperfections and defects leading to a remarkably irregular morphology that can significantly affect the product aesthetical and mechanical performance. Because of that, the part post-processing is a crucial step. Shot blasting is a simple and fast-finishing process commonly used in the AM supply chain to remove residual sintered particles attached to the component surface and reduce the surface roughness. This study investigates the shot blasting processes performed on AlSi10Mg and Ti6Al4V parts produced using laser-PBF (L-PBF) and electron beam-PBF (EB-PBF), respectively, considering the great geometric variability that a single component designed for AM can have in surface texture and geometries. Test artifacts were therefore devised with internal channels enclosed in the reticular structures and inclined flat surfaces to evaluate what happens in the external surface, internal channels, and reticular structures at the level of roughness and accuracy when these are simultaneously affected by the flow of abrasives. The effect of glass and zirconia microspheres and their combination on the surface roughness are analyzed. The results show a reduction of surface roughness up to approximately 38% for L-PBF and 82% for EB-PBF parts without altering their geometrical characteristics and processing the part for less than 1 min.