Metal Additive Manufacturing Conference 2019

Additive Manufacturing provides many opportunities to design and manufacture parts that are difficult or not possible to produce with conventional methods, but in some cases even more important, to be able to produce these or any metal replacement parts in remote places like the moon or Mars. In laser powder bed fusion (LPBF), melt pool dynamics and stability is dependent on a large number of factors, e.g. laser power output, power density, travel speed, reflectivity of powder bed, rapid heating and vaporization. Since travel speeds are often very fast and the laser interaction zone is small, the physical events become difficult to predict but also to observe. This work aims to describe the formation and geometrical characteristics of the vaporization zone and its consequences on the powder bed during processing. Using a combination of theoretical descriptions, resulting material structures and a comprehensive analysis of high-speed images of the processing zone, explanations for the dynamic melt pool behavior are derived. These findings will be used to predict LPBF processability in different gravitational fields, resulting in estimation of feasibility of its use on interstellar bodies with varying gravity.