Manufacturing of single-process 3D-printed piezoelectric sensors with electromagnetic protection using thermoplastic material extrusion

Material extrusion with a thermoplastic polymer enables the simultaneous fabrication and poling of piezoelectric sensors; however successful implementation of electromagnetic interference (EMI) protection has yet to be achieved. This research addresses key challenges such as encapsulating the sensor in a limited space without affecting the poling process, the high resistance of the conductive filaments causing low-pass charge filtering, and the need for electrical contact with EMI-protected measurement devices. The presented design principles enable the fabrication of a fully 3D-printed piezoelectric sensor in a single process that includes a piezoelectric sensing element, wire, and a connector interface, all EMI shielded. Strategies such as inter-trace extrusion filling and electrode ironing are introduced to avoid electrode short circuits and electric poling issues. In addition, the 3D-printed interface allows direct connection to commercially available connectors and measurement devices. As a force sensor, the fully 3D-printed piezoelectric sensor with full EMI shielding has an excellent signalto-noise ratio of 27 dB and reduces noise for more than two orders of magnitude if compared to the partially shielded sensor. This research is an important step forward in fabricating and embedding piezoelectric sensors in a single process that offers a wide range of applications in fields such as structural health monitoring, robotics, and biomedical engineering, where a high degree of customization is required.

Automated summary

This research addresses the challenges in implementing electromagnetic interference (EMI) protection for material extrusion-based piezoelectric sensors, such as limited space encapsulation, low-pass charge filtering, and electrical contact with EMI-protected devices. By introducing design principles and strategies, a fully 3D-printed piezoelectric sensor with EMI shielding and direct connection to measurement devices is fabricated. The sensor demonstrates high signal-to-noise ratio and significantly reduced noise compared to partially shielded sensors. This research is a crucial step towards the integration of piezoelectric sensors into various applications.