Compatibility Study of Polymeric Binders for Aluminum Binder Jet Parts

Abstract

Binder jetting of aluminum powder has progressively gained industry interest especially from automotive and aerospace for the fabrication of lightweight products. However, the interactions between the polymeric binders and oxidative behavior of aluminum powder have not yet been extensively studied by researchers. Hence, this research focuses to understand the impact of different polymeric binders on the final quality of the fabricated sample through performing composition and porosity analyses. The resulting impurity levels and final density were evaluated to identify the most compatible polymer binder for aluminum powder. Five liquid binders were prepared and utilized to fabricate green state samples with the AlSi10Mg powder. The lowest level of impurities was obtained with the alcohol solvent-based binders whereas organic solvent-based binders, such as highly non-reactive thermoplastic fluoropolymer and cyanide-based synthetic polymer, and water-based binders were reported to deposit moderate to high binder residues on the samples after the debinding heat treatment. The alcohol solvent-based binder provided the highest sintered density of 95.1%, while the PVA binder delivered the lowest sintered density. Hence, this research recommends the PVP binder as the most suited binder among the considered binders as it provided the highest densification with minimal chemical interactions with the aluminum powder.