Multi-Material Binder Jet Printing of Functional Ni-Mn-Ga Alloys

Additive manufacturing has the well-known benefits of reduced waste material and geometrical freedom in parts. Powder bed binder jet 3D printing is a type of additive manufacturing that is versatile, is not energy based, operates in air at room temperature, and allows for controlled densification during postprocessing. In BJ-3DP, a layer of powder is spread flat by a roller on a build bed. A printhead selectively deposits binder onto the powder in a pre-determined path for that layer. The build bed moves down by one layer thickness, another layer of powder is spread, the binder is deposited, and the process repeats until the part is complete. After printing, the entire build bed of powder is heated in an oven to fully cure the binder, after which the parts can be handled but are still approximately 50-60% dense For metals, a common post-processing option is pressureless sintering, using only high temperatures to allow the metal powders to densify into a solid part that is 70-100% dense