3D Printing of Lead-Free Piezoelectric Ultrasound Transducers

Multi-material direct ink writing (DIW) of smart materials opens new possibilities for manufacturing complex-shaped structures with embedded sensing and actuation capabilities. In this study, DIW of UV-curable piezoelectric actuators is developed, which do not require high-temperature sintering, allowing direct integration with structural materials. Through particle size and ink rheology optimization, the highest d33*g33 piezoelectric constant compared to other DIW fabricated piezo composites is achieved, enabling tunable actuation performance. This is used to fabricate ultrasound transducers by printing piezoelectric vibrating membranes along with their support structures made from a structural ink. The impact of transducer design and scaling up transducer dimensions on the resonance behavior to design millimeter-scale ultrasound transducers with desired out-of-plane displacement is explored. A significant increase in output pressure with increasing membrane dimensions is observed. Finally, a practical application is demonstrated by using the printed transducer for accurate proximity sensing using time of flight measurements. The scalability and flexibility of the reported DIW of piezo composites can open up new advancements in biomedical, human-computer interaction, and aerospace fields. Multimaterial 3D printable, lead-free piezo-composites through direct printing and curing without high-temperature sintering, ensuring both high piezoelectric response and robust integration into structures. This approach enables cost-effective mass printing of piezoelectric ultrasound transducers into complex-shaped objects while fostering robust bonding between surfaces, offering a pathway to scalable and bio-compatible manufacturing of intelligent structures with built-in sensing and actuation capabilities. image