Exploring Clamping Mechanisms for Air-Coupled High-Power Ultrasound Transducers

Bolt-clamped Langevin ultrasound transducers are typically paired with horns, which require precise and costly manufacturing. We explore alternative clamping mechanisms aimed at optimizing transducer performance without the need for a horn. We develop low-cost, 3d-printed holders that are adaptable to various transducers, providing versatile and accessible solutions. Preliminary measurements reveal no significant differences between 28 kHz and 40 kHz transducers, leading us to focus on the 40 kHz variant. Detailed surface velocity analyses are performed using a laser Doppler vibrometer. Our results demonstrate that selecting an inappropriate clamping strategy can significantly distort the surface velocity profile, while clamping directly on the piezoelectric discs results in the most balanced surface velocity distribution, achieving a maximum velocity of 972 mm/s. These findings suggest that our clamping strategies are universally applicable across this frequency range of bolt-clamped Langevin transducers, enhancing reproducibility and reliability.