How the nozzle position affects the geometry of the melt pool in directed energy deposition process

This work deals with Directed Energy Deposition (DED) that is a process in which the material is delivered directly into the melt pool. Several kinds of nozzle have been developed and used in this process. However, the position of the nozzle, mainly for the lateral one, plays a crucial role in the geometry and porosity content of the melt pool. Therefore, to investigate the correlation between the lateral nozzle position and the geometry of the melt pool, three different sets of single tracks of Ti-6Al-4V were deposited at different nozzle positions. It was found that helpful information regarding the selection of the optimal position of the lateral nozzle can be obtained from the melt pool features. It can be noticed that by increasing the distance between the nozzle position and substrate, the powder capture decreases and accordingly results in a high depth of fusion zone and also keyhole defect formation.