Suppressing spatter reduces random defects in metal 3D printing

Controlling spatter during laser powder bed fusion – a form of 3D printing that uses metal as a medium – reduces random defects and increases the overall reliability of built parts. New technologies capable of 3D printing metallic materials are poised to revolutionize manufacturing, particularly for advanced aerospace and biomedical applications. One such technology – laser powder bed fusion (L-PBF) – uses a high-power laser to melt and fuse metallic powders layer-by-layer to produce an intricate 3D part. However, despite their promise, widespread application of metal 3D printing has yet to be realized, primarily due to their sub-optimal operational reliability. Due to an accumulation of various defects, such as pores randomly generated during the printing processes, L-PBF printed parts often do not consistently meet adequate standards. To solve these issues, critical gaps in the understanding of the physics underlying the L-PBF printing process – including the complex dynamics between the laser, powder layer and melt pool that occurs where the two meet – must be addressed. Using a predictive multi-physics model and x-ray synchrotron experiments to capture fast and fleeting laser-powder-melt pool dynamics, Saad Khairallah and colleagues explored how best to reduce variability and the defects in L-PBF prints. Khairallah et al. discovered several previously unknown effects caused by spatter – a common and likely underestimated occurrence in L-PBF printing – that can lead to the formation of defects and deformations. According to the results, spatter issues can be mitigated by carefully controlling laser power, which helps to minimize the random formation of defects and ensure reproducible, high-quality prints. Andrew Polonsky and Tresa Pollock discuss the study’s findings further in a related Perspective.

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