Laser powder bed fusion process combined with infrared heating for reduced residual stress and support-free fabrication of parts

Conventional laser-based powder bed fusion (PBF-LB/M) for fabricating 3D metal parts requires support structures to secure the printed parts to a baseplate. However, these support structures often decrease printing efficiency and limit design freedom. In this study, a novel method to substantially reduce the thermal residual stresses produced during the PBF process has been developed by combining focused in situ infrared (IR) heating with conventional techniques. The reduced stress enables the fabrication of high-aspect-ratio Ti-6Al-4V thin walls and zero-degree overhang beams, which cannot be printed using conventional processes. Furthermore, this method allows for support-free printing of various 3D parts, including a level two Menger sponge and a hollow honeycomb cylinder. In the novel process, the IR-heated powder, with loose consolidation, functions as both a support structure to withstand internal thermal stresses and external impacts and as a heat sink. The IR-consolidated powder can be easily removed from the printed part and reused.