Experimental study and modeling of melt pool in laser powder-bed fusion of thin walls

Abstract

Laser powder-bed fusion (L-PBF) is promising for manufacturing of lightweight cellular structures. A thin wall is the key element of such structures. Heat and mass transfer in the melt pool formed on the top of a thin wall is essentially two-dimensional. That is why L-PBF process parameters adapted for thin walls strongly differ from those necessary for bulk material. In the present work, a high speed camera records a side view of the melt pool formed on the top of a thin metallic wall due to a laser beam scanning along the wall edge. The melt pool profile and the position of the keyhole are observed. The results are compared with a two-dimensional model of coupled heat conduction and Marangoni convection in the laser-interaction zone. In the studied conditions, the best agreement between the experiment and the modeling implies that a keyhole is formed with the depth comparable with that of the melt pool.