Development and thermal characterization of new 3D printed strain sensors

Nowadays, sensors fabrication is facing a challenging scenario involving the introduction of additive manufacturing (AM), or 3D printing, in many application fields such as aerospace and biomedical industry. In particular, the exploitation of Fused Filament Fabrication (FFF) technology, which is the less expensive AM technology, has become widespread in recent years, allowing to fabricate smart objects with embedded sensors in a single-step fabrication cycle, such as strain sensors. FFF strain sensors are currently object of research [1], [2], with the main aim of i) obtaining small electrical resistance to reduce measurement noise, and ii) reducing the variability of the resistance between multiple specimens of the same 3D-printed strain sensor (obtained with identical design and fabrication process), in order to enable mass-production and to obtain accurate balancing when connected in a Wheatstone bridge configuration. In this research we present new low-cost 3D-printed strain sensors manufactured using FFF technology, by employing three different commercial materials for the conductive track. Design and printing parameters have been optimized by performing a design of experiment (DoE), with the aim of reducing electrical resistance and its variability, and a thermal characterization has been conducted to understand the relationship between resistance and temperature variation.