Role of infill density and pattern in electrical properties of fused filament fabricated mutual capacitance sensors

Abstract As the dynamic development of human–machine interfaces increases the demand for interactive sensors, this work demonstrates the successful fused filament fabrication of mutual capacitance sensors on acrylonitrile butadiene styrene substrates using conductive polylactic acid filament. The capacitor electrode infill density and infill pattern were selected as the two main variables to study their effects on the electrical behavior of the printed sensors. The variation in density is found to affect the electrode structure and, consequently, the resistance of the sensor electrodes, while changes in the infill pattern do not significantly alter it. The capacitance of the sensors is found to range from 0.5 to 2.2 pF, without and with external, controlled stimuli, respectively, and is independent of both the infill density and pattern. This capacitive behavior suggests that these variables can be optimized for the production of low-cost mutual capacitance sensors, minimizing both material use and production time.