Design and characterisation of thin film resistive sensors on additively manufactured polyamide 12 parts

Abstract Although numerous studies have investigated methods to improve the surface quality of additively manufactured polyamide 12 (PA12) parts, few have demonstrated the practical benefits of these enhanced surfaces in functional applications. This study bridges this gap by developing a proof of concept for equipping prototype PA12 components with resistive thin film sensors. This study aims to demonstrate the feasibility of sensor integration, emphasising scientific measurement as the primary goal rather than industrial implementation. Following the surface treatment, titanium and gold thin films were sputtered onto the parts, and the resistive sensors were laser-patterned. The thin films were characterised, and the sensor performance was evaluated. The resistive strain gauges exhibited good linearity under cyclic loads ranging from 40 to 80 g, with the bending beam undergoing an average negative strain of 513.6 µm/m. The temperature sensor, tested between 0 and 75 °C, demonstrated a strong linear correlation with a reference sensor, achieving a sensitivity of 0.21 Ω/ °C. These findings indicate that resistive thin film sensors can be effectively integrated on additive-manufactured polyamide 12 components, opening possibilities for their use in functional applications.