A high-frequency generator in the ultrasonic bath produces about 35000 oscillations per second, which are transferred into the cleaning solution and cause it to resonate. The energy density of the sound field is so high that a cavitation effect sets in. Innumerable extremely small vacuum bubbles develop in the ultrasonic bath and collapse in microseconds due to pressure and suction. The pulses triggered by this remove dirt particles even at the deepest, least accessible places or they result in homogenisation, dispersion and degassing.