Reducing distortion using a displacement-controlled hatching strategy in PBF-LB/M

Abstract In the process of additive manufacturing, specifically powder bed fusion of metals using a laser beam (PBF-LB/M), dealing with the in-situ distortion of overhang structures is a major challenge. In this study, a displacement-controlled hatching strategy is proposed based on displacement simulation results to reduce such displacements. The residual displacement for a propeller-geometry was predicted using the inherent strain method. Subsequently, the hatch vectors were planned orthogonal to the simulated displacement vectors. The findings indicate that aligning the hatch orientation based on simulation results decreases displacement. The median out-of-plane displacement of a propeller blade (AlSi10Mg) was reduced by up to 70% relative to a reference scan strategy. However, no significant benefit of the displacement-controlled hatching strategy was observed for the manufacturing of shallow overhangs below 15° in the investigated geometry. This approach shows potential for enhancing the precision and stability of PBF-LB/M processes. However, the recoater and gas flow direction were limiting constraints on the application of the proposed hatching strategy and need to be considered in an automated application of the proposed hatching strategy.