Fused filament fabrication 3D printing with low-melt alloys

3D-printing polymers using fused filament fabrication (FFF) technology has shown to fabricate complex functional parts for electronic, automotive, and biomedical applications. However, there is limited knowledge and understanding of 3D printing with pure metal feedstock using FFF technology. The use of 3D printing of metals and its alloys using FFF technology can provide low-cost alternatives and solutions to the laser-powder bed fusion process. In current work, low-melting eutectic alloy of bismuth (58% Bi, 42% Sn), non-eutectic alloy of bismuth (40% Bi, 60% Sn), and a non-eutectic alloy of antimony (7.5% Sb, 89% Sn) have been used as a starting material and evaluated for FFF 3D printing using two approaches. In the first approach, a low-melting alloy in the form of wire was used as the feedstock for FFF extrusion. In this approach, the influence of FFF process parameters such as infill ratio, extrusion velocity, feed rate, nozzle temperature and bed temperature on the part fabrication were evaluated for successful fabrication of 2D and 3D geometries and characterized for density, precision, mechanical properties, and microstructure. In the second approach, low-melting alloys were cast onto 3D-printed molds to create metal structures. With this approach, the fabricated specimens were evaluated for its part formability, density, precision, mechanical properties, and microstructure. In addition, both approaches were used to fabricate a prototype specimen such as a souvenir and a prototype wrench. It is expected that such a technology will pave the way for the affordable fabrication of metal prototypes and alternatively on-demand custom metal spare parts for in-space applications and future space missions.