Melt Pool Monitoring for the Laser Powder Bed Fusion Process

In the laser powder bed fusion (L-PBF) process, metal powders are selectively melted with a laser beam to create complex geometries. Defects such as porosity, distortions and property variations have been detected in L-PBF parts. These defects yield unreliable products and represent a badly repeatable process that is strongly sensitive to part geometry, mainly caused by variations in heat dissipation. The present work studied a new melt pool monitoring system to link the laser energy density input with the final material density and porosity obtained for the L-PBF parts. The signal was monitored for two levels of laser power. The results illustrate the feasibility of applying the monitoring system to control the process parameters and adapt the energy input for each geometrical feature whenever necessary. The resulting more robust and repeatable process can create reliable parts to be certified for the aerospace, biomedical and automotive industry