Abstract Scope |
In binder jetting, liquid binder is selectively jetted onto a powder bed to fabricate parts in a layer-wise fashion. Following printing, the binder is cured to increase green part strength and then pyrolyzed during sintering. While the binder defines part geometry and provides green part strength, its presence can also hinder sintering densification due to the entrapment of residual char. In this study, the authors explore the tradeoff of the role of binder by investigating the effects of printing “shelled” parts (i.e., only the “shell” of the part geometry features bound powders, and the interior contains unbound powders) on final part quality. To investigate the effect of selective binder deposition on part quality, parts with varying shell thickness were printed; their relative density, dimensional shrinkage, pore morphology and distribution, microstructure, and mechanical strength were evaluated. Shelled parts demonstrate an increase in final density of ~5% over traditional binder jetted counterparts. |