Fabrication of ceramic bone scaffolds by Solvent jetting 3D printing and sintering: Towards load-bearing applications

High porosity and interconnected pore size are crucial factors for bone scaffolds. However, since porosity is inversely related to strength, the microstructure must be optimized to achieve bone scaffolds suitable for load-bearing applications. The powder bed 3D printing method can fabricate the highly porous parts possessing the desired properties using micron-sized ceramic powders (>30 μm) and polymeric ink, however, low sinterability and, consequently, low strength is still a problem. In this study, nano-scale powders are granulated and printed by a special 3D printing method called ‘solvent jetting on granulated feedstock containing binder’ to achieve an interconnected macropore structure with high strength. The advantages of this method, aside from the above mentioned, include obtaining controllable porosity, high strut density, wide neck formation, and small grain size; all of which are beneficial to mechanical strength. Using this method, a purely ceramic sample with 30 % porosity and compressive strength of 113.1 MPa was obtained. Furthermore, a bone scaffold prototype with total porosity of nearly 50 % and mechanical strength of 30.2 MPa was fabricated. These procedures and results are described and compared to another solvent jetting method which uses micron-sized powders.