3D printing electronic components and circuits with conductive thermoplastic filament

This work examines the use of dual-material fused filament fabrication for 3D printing electronic components and circuits with conductive thermoplastic filaments. The resistivity of traces printed from conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers was found to be 12, 0.78, and 0.014 Ω cm, respectively, enabling the creation of resistors with values spanning 3 orders of magnitude. The carbon black and graphene filaments were brittle and fractured easily, but the copper-based filament could be bent at least 500 times with little change in its resistance. Impedance measurements made on the thermoplastic filaments demonstrate that the copper-based filament had an impedance similar to a copper PCB trace at frequencies greater than 1 MHz. Dual material 3D printing was used to fabricate a variety of inductors and capacitors with properties that could be predictably tuned by modifying either the geometry of the components, or the materials used to fabricate the components. These resistors, capacitors, and inductors were combined to create a fully 3D printed high-pass filter with properties comparable to its conventional counterparts. The relatively low impedance of the copper-based filament enabled its use for 3D printing of a receiver coil for wireless power transfer. We also demonstrate the ability to embed and connect surface mounted components in 3D printed objects with a low-cost ($1000 in parts), open source dual-material 3D printer. This work thus demonstrates the potential for FFF 3D printing to create complex, three-dimensional circuits composed of either embedded or fully-printed electronic components.