Effects of Infill on the Additive Manufacturing of Piezoresistive Pressure Sensors

Abstract

The surge of growth in additive manufacturing (AM) has brought about increased interest in smart devices and advanced manufacturing. Fused Filament Fabrication (FFF) often presents itself as the starting equipment for industrial applications and hobby enthusiasts. The introduction of conductive polymer composites into FFF has brought about widespread capabilities, particularly in the areas of flexible sensors, printed electronics, and other multi-functional materials. Piezoresistive sensors have especially been of interest due to their use in wearable electronics and structural health monitoring coupled with the increasing commercial availability of conductive thermoplastic filaments. However, while much research has been devoted to the geometrical parameters in piezoresistive sensors in conventional manufacturing, little has been investigated with respect to additive manufacturing. Here, we present a unique method for tailoring the sensitivity of FFF produced flexible pressure sensors by altering the infill printing settings, therefore affecting the electromechanical response. Sensors were printed using common infill patterns (Concentric, Grid, Gyroid, Honeycomb, Lines, and Cubic) and low infill percentages (5–15%) capable of sensitivities of 2,010 kPa−1 under an applied pressure of up to 60 kPa and 530 kPa−1 under an applied pressure of up to 950 kPa. This work demonstrates the ease-of-fabrication and performance of flexible pressure sensors using an inexpensive and simple fabrication method.