1. Not conducive to the effect of voids

Two types of cavities actually occur during ultrasonic cleaning. One type is a bubble like cavity formed by the vaporization of gas dissolved in the cleaning solution; One type is the true cavity formed by the steam evaporated from the cleaning solution solvent. Due to the small volume of bubble like voids, the shock wave that occurs when they rupture is also relatively weak. And the shock wave generated by the true void generated by steam during rupture is more than 10 times stronger. When there are many gases dissolved in the cleaning medium, the voids that occur are mainly bubble voids. Only after degassing and removing these gases is it conducive to the occurrence of true voids. And use powerful shock waves from real cavities to crush and peel off stubborn dust and dirt attached to the workpiece.

2. Not conducive to the acceleration effect of ultrasonic vibration

The use of high-frequency ultrasonic cleaning is currently an important means of cleaning ultra-fine workpieces. Its principle is to use ultrasonic waves to greatly improve the vibration acceleration of the cleaning solution to achieve the cleaning purpose. When a huge vibration acceleration is applied to the workpiece, the dust particles on its surface are easily peeled off. Because high-frequency ultrasound causes minimal damage to workpieces, it is commonly used for cleaning fine and complex workpieces such as semiconductor and liquid crystal display substrates. But if there are many gases dissolved in the cleaning solution, the propagation speed of ultrasound in the cleaning solution will be attenuated, and its common cleaning effect cannot be exerted. Therefore, vacuum degassing treatment should also be carried out when using high-frequency ultrasonic cleaning.

3. Dissolved gas causes oxidation of cleaned workpieces

The dissolved gas contains an appropriate amount of oxygen, which can cause oxidation or rusting of metal workpieces during ultrasonic cleaning. Vacuum degassing treatment can greatly reduce the residual oxygen content in the cleaning solution, which not only reduces the time for cleaning and drying, but also effectively addresses rust prevention issues.

The use of vacuum degassing equipment such as vacuum generators can reduce the residual dissolved oxygen in various cleaning agents to below 2mg/L. The power of the cleaning agent used for ultrasonic cleaning after vacuum degassing treatment is greatly improved, especially for the cleaning of fine parts with complex shapes and small pores.

This includes two functions:

One is to use the effect of bubbles expanding in the pores during the degassing process to remove dust and dirt; Another function is to utilize the outstanding cleaning ability of the degassed cleaning solution introduced above.

The specific process of the vacuum degassing ultrasonic cleaning machine is as follows: during cleaning, the object to be cleaned is first put into the cleaning solution under normal pressure, and the cleaning solution penetrates into the pores or deep holes of the workpiece. Then, vacuum degassing treatment is carried out. During the process of reducing pressure and vacuuming, the small bubbles dissolved in the cleaning solution are caused to expand in the pores with the decrease of air pressure, and then the dust and dirt are carried out together. Then, under vacuum conditions, the ultrasonic generating equipment is started, and the ultrasonic waves are used to perform outstanding cleaning in the degassed cleaning solution to remove the dust and dirt. Then start the circulation pump to circulate the cleaning solution under vacuum and remove the dust and dirt through the filter. To improve the cleaning effect, the cyclic operation of reducing pressure, degassing, and restoring to normal pressure can be repeated to increase the transmission power of ultrasonic waves and enhance the peeling effect on dust and dirt.

Article source: Jiangmen Ultrasonic Cleaning Machine http://www.kpzfcsb.com/