In powder bed fusion of metal with laser beam (PBF-LB/M), repetitive melting and solidification of newly added layers lead to thermal stresses and distortions during part build-up. Particularly at critical component features such as unsupported overhangs, super-elevated edges pose a risk in terms of crashes with the recoating system during powder spreading. Damaged recoater lips lead to irregularities in the form of stripes in the powder bed. These local inhomogeneities cause lack-of-fusion porosity and geometric defects on the part surface. However, quantitative information on important quality aspects, such as tensile properties, dimensional accuracy, roughness, and hardness of parts printed under irregular powder bed conditions is scarce. Here, we show that samples from build jobs with recoater crashes maintain their elastic tensile properties and hardness, but lose elongation at break. Finite-element simulations of in-process distortions are used to design an artifact that intentionally damages the silicone rubber lip of the recoater but does not cause machine breakdown. The lowest mean yield strength of the damage-affected samples is 243 MPa, which is still within the material data sheet limits for AlSi10Mg. Therefore, recoater crashes do not necessarily result in rejects, but users must consider the likely presence of porosity.

The adoption of Design for Additive Manufacturing (DfAM) practices brought new industrial components embedding unconventional shapes such as lattice structures or freeform surfaces resulting from topological optimisations. As a drawback of design freedom, designers need to use thermal post-processing to achieve homogeneous properties in metal 3D printing. This contribution analyses the effect of T6-like heat treatment on the hardness of a complex component. Hardness values are reported along with good design practices for effective thermal post-processing to complement the DfAM knowledge base.