Leveraging multiple lasers in powder bed fusion

Multi-laser PBF systems are commercially available and driven by the increasing demands for higher AM production rates. However, a multi-laser system is not simply the duplication of a single laser system in one machine. On top of the laser-material interactions present in a single laser system, a second laser introduces laser-laser interactions, and they may affect each other's laser-material interactions as well. In this project, the PhD candidate is expected to focus on multi-laser powder bed fusion process optimization through experimental work, thermal simulations to estimate thermal distributions, and in process monitoring. Specifically, the work consists of: Mapping the inherent process variability in a multi-laser systems. Perform thermal and thermomechanical simulations of dual laser scanning. Using the above results, combined with a detailed understanding of the alloy under investigation, to manipulate the dual-laser process conditions to induce or avoid microstructural changes (allotropic transformations, secondary particle precipitation, solidification structures, cracking, …), and/or lower residual stress. The final goal of this PhD project is to improve our understanding of the various interaction mechanisms in a multi-laser system, in particular the thermal interaction inside the part, by using a combination of in situ process monitoring, thermal/thermomechanical simulations, and post-process material characterization. This understanding translates into the design of scan strategies that take the interactions into account by either avoiding or leveraging them to manipulate the local material microstructure, and better resulting part properties. The work requires a combination of machine control (through Python or dedicated software API's), experimental work, simulation, and material characterization.