Ultrasonic cleaning utilizes the direct and indirect effects of ultrasonic cavitation, acceleration and direct flow on liquid and dirt, so that the dirt layer is dispersed, emulsified and peeled from the surface of the workpiece to achieve the purpose of cleaning. In the ultrasonic cleaners currently used, cavitation and direct flow are used more often.
  
(1) Cavitation: Cavitation is the transmission of ultrasonic waves to the liquid with an interactive high-frequency transformation of compressive force and pressure reduction of more than 20,000 times per second. During the pressure reduction, the vacuum nucleus bubbles are generated in the liquid. When the compression force is applied, the vacuum nucleus bubbles generate a strong impact force when crushed by the pressure, thereby peeling off the dirt on the surface of the object to be cleaned, thereby achieving cleaning the goal of.
   In the ultrasonic cleaning process, the floating bubbles that can be seen by the naked eye are not vacuum nuclear group bubbles, but air bubbles, which inhibit the cavitation and reduce the cleaning efficiency. Only when the air bubbles in the liquid are completely removed, the cavitation vacuum nuclear bubble can achieve the best effect. Therefore, some cleaning processes use degassing to achieve the effect of precision cleaning.
  
(2) Straight flow: The phenomenon that ultrasonic waves flow in the liquid along the propagation direction of sound waves is called straight flow. When the intensity of the sound wave is at a certain density (0.6W/cm2), the naked eye can see a straight flow, which is perpendicular to the vibration surface, and the flow velocity is about 10cm/s. Through this direct flow, the oily dirt on the surface of the object to be cleaned is stirred, and the cleaning solution on the surface of the dirt also generates convection. The dissolved solution that dissolves the dirt is mixed with the new solution to speed up the dissolution and play a very important role in the transportation of the dirt. Great effect.
  
(3) Acceleration: The acceleration produced by the liquid particles. For ultrasonic cleaners with a higher frequency (such as 40KHz), the cavitation effect is very insignificant. At this time, the cleaning mainly relies on the acceleration of the liquid particles under the ultrasonic action to hit the particles for ultra-precision cleaning of the dirt.