Validated Computational Modelling Techniques for Simulating Melt Pool Ejecta In Laser Powder Bed Fusion Processing

Industry currently require faster build rates from laser powder bed fusion processes. As such, higher power lasers and multi-laser systems are being explored. Due to instabilities in the melting process, material is ejected from the melt pool in the form of spatter and vapour. Previous work has shown that these ‘ejecta’ can result in attenuation of the laser and redeposition of lager particles onto the powder bed; which can lead to poor mechanical properties. ANSYS Fluent was used to create a CFD model which was validated against hot wire anemometry results from Renishaw’s RenAM 500Q. This was then coupled with a Discrete Phase Model (DPM) to track the ejection of spatter and vapour from the melt pool through the chamber. This has led to a better understanding of the removal of ‘ejecta’, leading to increased mechanical properties and lower rates of build failure.Mechanical Engineerin