This research focused on extending the applications of fused deposition modeling (FDM) by extrusion and deposition of low melting temperature metal alloys to create three-dimensional metal structures and single-layer contacts which may prove useful for electronic interconnects. Six commercially available low melting temperature solder alloys (Bi36Pb32Sn31Ag1, Bi58Sn42, Sn63Pb37, Sn50Pb50, Sn60Bi40, Sn96.5Ag3.5) were tested for the creation of a fused deposition modeling for metals (FDMm) system with special attention given to Sn–Bi solders. An existing FDM 3000 was used and two alloys were successfully extruded through the system's extrusion head. Deposition was achieved through specific modifications to system toolpath commands and a comparison of solders with eutectic and non-eutectic compositions is discussed. The modifications demonstrate the ability to extrude simple single-layer solder lines with varying thicknesses, including sharp 90 deg angles and smooth curved lines and showing the possibility of using this system for printed circuit board applications in which various connections need to be processed. Deposition parameters altered for extrusion and the deposition results of low melting temperature metal alloys are introduced.

The intersection between nanoscience and additive manufacturing technology has resulted in a new field of printable and flexible electronics. This interesting area of research tackles the challenges in the development of novel materials and fabrication techniques towards a wider range and improved design of flexible electronic devices. This work presents the fabrication of a cost-effective and facile flexible piezoresistive pressure sensor using a 3D-printable carbon nanotube-based nanocomposite. The carbon nanotubes used for the development of the material are multi-walled carbon nanotubes (MWCNT) dispersed in polydimethylsiloxane (PDMS) prepolymer. The sensor was fabricated using the direct ink writing (DIW) technique (also referred to as robocasting). The MWCNT-PDMS composite was directly printed onto the polydimethylsiloxane substrate. The sensor response was then examined based on the resistance change to the applied load. The sensor exhibited high sensitivity (6.3 Ω/kPa) over a wide range of applied pressure (up to 1132 kPa); the highest observed measurement range for MWCNT-PDMS composite in previous work was 40 kPa. The formulated MWCNT-PDMS composite was also printed into high-resolution 3-dimensional shapes which maintained their form even after heat treatment process. The possibility to use 3D printing in the fabrication of flexible sensors allows design freedom and flexibility, and structural complexity with wide applications in wearable or implantable electronics for sport, automotive and biomedical fields.