Mitigation of Residual Stress and Distortion of AlSi10Mg Parts Produced by Laser Powder Bed Fusion through a Proper Selection of Support Geometry

Laser beam powder bed fusion (LB-PBF) is an edge additive manufacturing technology that allows complex near-net shape components to be produced. The freedom of design of the LB-PBF process makes it possible to produce optimized geometries, driving the application of this process in sectors in which high performance is fundamental such as aerospace and automotive. However, the building process inherently generates residual stresses in the part and the use of support structures become essential to anchor the part to the building platform and avoid problems in the downfacing surfaces that may warp or collapse during the production process. In this paper, different support densities obtained using different geometries of support structures are investigated to evaluate how they affect the residual stress distribution in the supported part. Two families of support structures were considered, linear-type and volumetric-type, including also a hybrid support structure that combined a massive volume topped by a linear support structure. Results highlighted that the combined choice of support density and geometry influences the magnitude and the distribution of sub-superficial residual stresses near the support-part interface and that appropriate design is essential to prevent excessive distortion or failure.