Design and Fabrication of FDM 3D Printed Strain Sensors

As technology related to virtual reality, prosthetics, and robotics advances there appears a need for better sensor technology to augment these systems. In particular, many of the systems must interphase with the human body or the environment while maintaining large amounts of mobility and flexibility. This creates the demand for flexible electronics in particular flexible strain sensors to monitor movement. The work presented here explores the feasibility of commercially available elastic filament and desktop Fused Deposition Modeling (FDM) 3D printing as a simple and cost-effective route to develop flexible single-axis strain sensors. 3D printing allows for the rapid production and prototyping of designs at relatively low cost. 3D printing is used to fabricate the strain sensor substrate. The sensitivity of the strain sensor is then observed by calculating the gauge factor from experimental data. From this, the viability of FDM 3D printing and commercially available filament for the creation of strain sensors can be determined. Three sensors measuring approximately 2100 μm by 199 μm are fabricated. Results demonstrate gauge factors from 1 to 2 at 38.6% strain with high linearity and little hysteresis. Additionally, two smaller strain sensors, measuring approximately 696 μm by 203 μm, are fabricated with gauge factors of nearly 0.9 at 13% strain. Results show that stress accumulation and permanent deformation play an essential role in determining the functionality of these 3D printed sensors. The results from this work demonstrate the potential of additive manufacturing to produce complex designs and sensor platforms for a wide range of applications