The effect of inkjetted nanoparticles on metal part properties in binder jetting additive manufacturing

Binder jetting AM has been used to fabricate metal parts by first jetting a binder into a powder bed, and then sintering the resulting green part wherein the binder is removed and the metal particles are fused. Sintered part properties can be enhanced when nanoparticles are suspended into a solvent-based organic binder, as the inkjetted nanoparticles can reduce sintering shrinkage and increase mechanical strength. In this work, the authors also used a nanoparticle suspension without organic adhesives as a means for binding metal powder bed particles together. After being deposited into the powder particles' interstices, the jetted nanoparticles are sintered at a temperature lower than the powder sintering temperature via a heated powder bed, to provide strength to the printed green part. Compared to organic binders, the use of jetted nanoparticles provided a permanent bonding which improved the structural integrity of printed parts during sintering.