[Lindsay] has a wonderful writeup about a new toy in the shop, an ultrasonic transducer. The 28kHz, 70W bolt-clamped Langevin transducer by itself is not much use, you need a power supply ...

Ultrasonic welding is based on high-frequency vibrations (typically between 20 and 40 kHz) that cause surface friction and viscoelastic heating at the weld. The most important process parameters are ...