Abstract
3D printing technologies have advanced significantly in recent years allowing for additive manufacturing of new structured materials, expanding the range, function, and capabilities of manufactured components. In this work, flexible capacitors were produced using additive manufacturing and compared to commercially available capacitance sensors in strain testing. The sensors utilize thermoplastic polyurethane (TPU) printed using fused filament fabrication methods as a dielectric substrate and a combination of flexible inks for production of the conductive surface. Flexible inks were printed using syringe based deposition methods on a custom designed printer using the TPU substrate. Results demonstrated successful capacitor production with capacitance values ranging from 2–70 pF depending on geometry, material, and printing conditions. The 3D printed flexible capacitors were characterized over a frequency range of 100 Hz to 10 kHz and compared to commercial roll-to-roll produced capacitors. Strain testing was conducted from 0–50% strain using a mechanical testing machine for the range of sensors and final capacitance post strain was measured to calculate deviation from original capacitance values. The sensors exhibited a relatively linear increase in capacitance when strained and returned to a resting position upon release of strain with minimal hysteresis effects, demonstrating their utility as 3D printed sensors.
