The sound that people hear is a sound wave signal with a frequency of 20-20000Hz. Sound waves above 20000Hz are called ultrasonic waves. The transmission of sound waves follows a sine curve of longitudinal propagation, with one layer strong and one layer weak, transmitted in sequence. When weak sound wave signals act on a liquid, they will generate a certain negative pressure on the liquid, that is, the volume of the liquid increases, the molecular gaps in the liquid increase, and many small bubbles are formed. When strong sound wave signals act on a liquid, they will generate a certain positive pressure on the liquid, that is, the volume of the liquid is compressed and reduced, and the small bubbles formed in the liquid are crushed. Through research, it has been proven that when ultrasound is applied to a liquid, the rupture of each bubble in the liquid produces a highly energetic shock wave, equivalent to instantly generating several high temperatures and up to thousands of atmospheres of pressure. This phenomenon is called "cavitation", and ultrasonic cleaning uses the shock wave generated by the rupture of bubbles in the liquid to clean and flush the inner and outer surfaces of the workpiece.

The second ultrasonic wave propagates in the liquid, causing the liquid and the cleaning tank to vibrate together at the ultrasonic frequency. The liquid and the cleaning tank vibrate at their own natural frequency, which is the frequency of sound waves, so people hear buzzing sounds. If there are any other unclear questions, you can send an email to miaoda @ and do my best.
1. What is ultrasound: Waves can be divided into three types, namely infrasound waves, sound waves, and ultrasound waves. The frequency of infrasound waves is below 20Hz; The frequency of sound waves is 20Hz~20kHz; The frequency of ultrasound is above 20kHz. The infrasound and ultrasound waves are generally inaudible to the human ear. Ultrasonic waves have good directionality and strong penetration ability due to their high frequency and short wavelength, which is why ultrasonic cleaning machines are designed and manufactured.
2. How to complete cleaning work with ultrasonic waves
Ultrasonic cleaning utilizes the cavitation, acceleration, and direct flow effects of ultrasonic waves in liquids to directly and indirectly disperse, emulsify, and peel off the dirt layer, achieving the purpose of cleaning. Currently, cavitation and direct flow are more commonly used in ultrasonic cleaning machines.
(1) Cavitation effect: Cavitation effect refers to the high-frequency transformation of ultrasonic waves into liquids through the interaction of compression force and decompression force at a rate of more than 20000 times per second. When the pressure is reduced, a phenomenon of vacuum nucleus bubbles is generated in the liquid. When the compression force is applied, the vacuum nucleus bubbles are crushed by the pressure and generate a strong impact force, thereby peeling off the dirt on the surface of the cleaned object and achieving precise cleaning.
In the ultrasonic cleaning process, the visible bubbles are not vacuum core bubbles, but air bubbles, which suppress cavitation and reduce cleaning efficiency. Only when the air bubbles in the liquid are removed can the cavitation effect of the vacuum core bubble be achieved.
(2) Direct flow effect: The phenomenon of ultrasonic waves flowing along the direction of sound propagation in liquid is called direct flow. When the sound wave intensity is 0.5W/cm2, a straight flow can be seen with the naked eye, which generates a flow perpendicular to the vibration surface with a flow velocity of about 10cm/s. Through this direct flow, the micro oil dirt on the surface of the cleaned object is stirred, and the cleaning solution on the dirt surface also generates convection. The solution that dissolves the dirt mixes with the new liquid, accelerating the dissolution rate and playing a significant role in the transportation of dirt.
(3) Acceleration: The acceleration generated by the propulsion of liquid particles. For high-frequency ultrasonic cleaning machines, the cavitation effect is not significant. At this time, the cleaning mainly relies on the acceleration of liquid particles under the action of ultrasonic waves to impact particles for ultra precision cleaning of dirt.
3. Composition: The ultrasonic cleaning machine mainly consists of an ultrasonic cleaning tank and an ultrasonic generator. The ultrasonic cleaning tank is made of sturdy, elastic, and corrosion-resistant stainless steel, and is equipped with an ultrasonic transducer oscillator at the bottom; The ultrasonic generator generates high frequency and high voltage, which is transmitted to the transducer through the cable connection line. The transducer resonates with the vibration plate at high frequency, so that the solvent in the cleaning tank is cleaned by ultrasonic waves to remove dirt.