Development of a Test Bench for the Experimentation of the Electrical Performance of 3D Printed Multi-Material Parts

Abstract

Obtaining multi-material parts by material extrusion processes is becoming more interesting as the available materials permit achieving superior properties in the 3D printed products. Combining conductive filament with other with elastomeric properties makes it possible to materialise electrical circuits for introducing active elements in specific parts, such as sensors, triggers or antennas. In this context, a test bench has been designed, manufactured and set-up, to evaluate the electrical behaviour of multi-material 3D printed test samples composed of two or more materials, being one a conductor of electricity (at least) and the other(s) non-conductive but flexible. The functionalities of the test bench include the possibility to apply tensile, compressive, shear, or flexural loads to the test samples. The electrical performance of the samples can be assessed in terms of resistivity and capacitance, in real time, when the test bench stands still and when it conducts the series of movements that produce the elastic deformation of the samples. To achieve this, three electronic circuits have been designed with their own corresponding control with Arduino: a circuit to measure the variation of the resistance of the test samples, a circuit to measure the variation of the capacitance of the test samples, and a circuit controlling the movements of the mechanical set (motor and terminals) that generates the deformation of the test samples. The test bench is connected to a desktop computer to ease the data export, treatment, and visualisation. As a set-up of the test bench, several preliminary experimentation measurements have been done to assess factors of interest such as sensitivity and a correlation index. The present work also frames the requirements of the parts to be tested in the bench and outlines the work procedure to carry out the series of experiments.