Influence of contaminants on part quality during Laser-Based Powder Bed Fusion of nickel base alloys

Laser-based Powder Bed Fusion (LPBF) has become a key Additive Manufacturing (AM) technology for the production of complex metallic components within a short lead-time. Contaminated powder feedstock is a major challenge in LPBF due to the uncertain influence of contaminations on part quality. This study investigates the effects of different contaminants inside the feedstock on material density and metallurgical structure in order to evaluate their implications for serial production. Pieces of rubber gloves, human, and recoater brush hair as well as five more substances were applied manually at a defined layer during the manufacturing process of Hastelloy® X (HX) specimens. The part densities were 99.9% for all contaminated specimens. Cross-sections did not show increased porosity. For some contaminants, inclusions of foreign material residue were observed. The results for HX were evaluated and implications for comparable materials were derived. Lastly, the criticality of the investigated contaminants on part quality was analyzed.