Thin, Flexible, Capacitive Force Sensors Based on Anisotropy in 3D-Printed Structures

Abstract

Conductive 3D-printed structures made out of a carbon doped thermoplastic polyurethane (TPU) deposited by an FDM 3D-printer show a high inter-layer contact resistance. Due to this poor resistive coupling capacitive effects between layers become prominent. This effect can be used to create capacitive force sensors by depositing only two thin layers of material. In this paper we investigate the feasibility of such a 3D-printed force sensor. The change in capacitance due to the compression of the material caused by an applied force (0 N to 10 N) is measured using an LCR meter. The presented sensor concept has a high potential for implementation in biomedical and soft robotic applications since the sensor is thin and flexible because it is made from soft material.