3D Printing and processing of miniaturized transducers with near-pristine piezoelectric ceramics for localized cavitation

The performance of ultrasonic transducers is largely determined by the piezoelectric properties and geometries of their active elements. Due to the brittle nature of piezoceramics, existing processing tools for piezoelectric elements only achieve simple geometries, including flat disks, cylinders, cubes and rings. While advances in additive manufacturing give rise to free-form fabrication of piezoceramics, the resultant transducers suffer from high porosity, weak piezoelectric responses, and limited geometrical flexibility. We introduce optimized piezoceramic printing and processing strategies to produce highly responsive piezoelectric microtransducers that operate at ultrasonic frequencies. The 3D printed dense piezoelectric elements achieve high piezoelectric coefficients and complex architectures. The resulting piezoelectric charge constant, d(33), and coupling factor, k(t), of the 3D printed piezoceramic reach 583 pC/N and 0.57, approaching the properties of pristine ceramics. The integrated printing of transducer packaging materials and 3D printed piezoceramics with microarchitectures create opportunities for miniaturized piezoelectric ultrasound transducers capable of acoustic focusing and localized cavitation within millimeter-sized channels, leading to miniaturized ultrasonic devices that enable a wide range of biomedical applications. Despite advances in additive manufacturing of piezoceramics, resultant transducers generally suffer from high porosity, weak piezoelectric responses, and limited geometry. Here, authors report the design and printing of fully packaged freeform ultrasonic transducers capable of traveling inside mm-sized channels and deliver localized high ultrasound energy.

Automated summary

By optimizing the printing and processing strategies of piezoceramics, highly responsive piezoelectric microtransducers can be produced. These 3D printed dense piezoelectric elements have high piezoelectric coefficients and complex structures, with a piezoelectric charge constant of 583 pC/N and a coupling factor of 0.57, approaching the properties of pristine ceramics. The integration of transducer packaging materials and 3D printed piezoceramics enables miniaturized ultrasonic devices capable of acoustic focusing and localized cavitation within millimeter-sized channels.