3D Bioplotter Research Papers

We present a novel additive manufacturing method for NiTi-Nb micro-trusses combining (i) extrusion-based 3D-printing of liquid inks containing NiTi and Nb powders, solvents, and a polymer binder into micro-trusses with 0/90° ABAB layers of parallel, ∼600 µm struts spaced 1 mm apart and (ii) subsequent heat-treatment to remove the binder and solvents, and then bond the NiTi powders using liquid phase sintering via the formation of a transient NiTi-Nb eutectic phase. We investigate the effects of Nb concentration (0, 1.5, 3.1, 6.7 at.% Nb) on the porosity, microstructure, and phase transformations of the printed NiTi-Nb micro-trusses. Micro-trusses with the highest Nb content…

Ni-29Mn-21.5Ga (at. %) wires are fabricated via a combination of (i) extrusion of liquid inks containing a binder, solvents, and elemental Ni, Mn, and Ga powders and (ii) heat treatments to remove the polymer binder and to interdiffuse and sinter the powders. To study the microstructural evolution, sintering mechanisms, and grain growth in these wires, both ex situ metallography and in situ X-Ray tomography were conducted while sintering at 800–1050 °C for up to 4 h. After debinding, Ga-rich regions melt and induce transient liquid phase sintering of the surrounding Ni and Mn powders, resulting in localized swelling of the wires and…

The development of in situ fabrication methods for the infrastructure required to support human life on the Moon is necessary due to the prohibitive cost of transporting large quantities of materials from the Earth. Cellular structures, consisting of a regular network (truss) of micro-struts with ∼500 μm diameters, suitable for bricks, blocks, panels, and other load-bearing structural elements for habitats and other infrastructure are created by direct-extrusion 3D-printing of liquid inks containing JSC-1A lunar regolith simulant powders, followed by sintering. The effects of sintering time, temperature, and atmosphere (air or hydrogen) on the microstructures, mechanical properties, and magnetic properties of…

Ni-Mn-Ga magnetic shape memory alloy (SMA) micro-trusses, suitable for high magnetic field induced strains and/or a large magnetocaloric effect, are created via a new additive manufacturing method combining (i) 3D-printing ∼400 μm struts with an ink containing a polymer binder and elemental Ni, Mn, and Ga powders, (ii) binder burn-out and metallic powder interdiffusion and homogenization to create the final alloy, and (iii) further sintering to increase strut density. Controlled amounts of hierarchical porosity, desirable to enable twinning in this polycrystalline alloy, are achieved: (i) continuous ∼450 μm channels between the printed Ni-Mn-Ga ∼300 μm diameter struts (after sintering) and…

Inks comprised of metallic Fe or Ni powders, an elastomeric binder, and graded volatility solvents are 3D-printed via syringe extrusion and sintered to form metallic cellular structures. Similar structures are created from Fe2O3 and NiO particle-based inks, with an additional hydrogen reduction step before sintering. All sintered structures exhibit 92–98% relative density within their struts, with neither cracking nor visible warping despite extensive volumetric shrinkage (≈70–80%) associated with reduction (for oxide powders) and sintering (for both metal and oxide powders). The cellular architectures, with overall relative densities of 32–49%, exhibit low stiffness (1–6 GPa, due to the particular architecture used), high…

A new method for complex metallic architecture fabrication is presented, through synthesis and 3D-printing of a new class of 3D-inks into green-body structures followed by thermochemical transformation into sintered metallic counterparts. Small and large volumes of metal-oxide, metal, and metal compound 3D-printable inks are synthesized through simple mixing of solvent, powder, and the biomedical elastomer, polylactic-co-glycolic acid (PLGA). These inks can be 3D-printed under ambient conditions via simple extrusion at speeds upwards of 150 mm s–1 into millimeter- and centimeter-scale thin, thick, high aspect ratio, hollow and enclosed, and multi-material architectures. The resulting 3D-printed green-bodies can be handled immediately, are…