Design and Modelling of 3D Printed Capacitive Displacement Sensor

The aim of the work is the realization and modelling of a simple capacitive displacement sensor with the use of 3D printing technology and polylactic acid (PLA) material. The sensor consists of three 3D printed PLA parts: two electrodes with cavities and a spacer. The silver paste is not printed but micromolded by filling it into the cavities of printed PLA electrodes via a syringe. The capacitance of the fabricated sensor versus applied displacement is measured and compared with calculated capacitance of simple sensor model. A simple model of a sensor capacitor is not capable of describing the behavior of this type of sensor. Therefore, more complex model of sensor capacitor is given better fit to measured results. Additionally, the hysteresis of the fabricated sensor is tested.