Finetuning design and process conditions to minimise manufacturing deviations in strut-based metal lattice structures produced by Laser Powder Bed Fusion

Metal lattice structures produced by Laser Powder Bed Fusion are increasingly being researched as the design freedom allows to minimise the weight and tune mechanical properties to application requirements. Nevertheless, lattice integration in structural components requires extensive design optimisation and modelling, and should preferably consider manufacturability, as not all lattice designs can be accurately produced. Geometrical and quality differences between the manufactured and designed parts complicate the modelling. This work implements two approaches to bridge the gap between the designed and manufactured parts for periodic strut-based lattices. First, a thorough process and parameter optimisation concludes that the optimal parameters and scan strategy to achieve a high material density and accurate design differ significantly for a lattice compared to bulk material. The multicontour scan strategy improves the material density compared to the contour ＋ infill scan strategy. Secondly, a thorough analysis of geometrical inaccuracies on a strut level confirms that the process leads to an elliptical instead of a circular strut cross-section. A linear compensation in the design successfully brings the cross-section of manufactured struts closer to the ideal circular cross-section. This compensation on a strut level can in the future be further implemented on a unit cell level.