The ultrasonic cleaning frequency ranges from 20-25-28-40-80-100-120kHz. The physical cleaning force caused by cavitation during the use of water or water cleaning agents is clearly advantageous for low frequencies, usually around 28-40kHz. For cleaning parts with small gaps, narrow slits, and deep holes, it is better to use high frequency, even several hundred kHz. When cleaning clock components, use 80kHz. If broadband FM cleaning is used, the effect will be better.

2、 Power selection

The effectiveness of ultrasonic cleaning is not necessarily proportional to the power multiplied by the cleaning time. Sometimes, even with low power, it takes a long time to remove dirt. If the power reaches a certain value, sometimes the dirt can be quickly removed. If the power is chosen to be too high, the cavitation intensity will be greatly increased, and the cleaning effect will be improved. However, this will also cause corrosion points on more precise parts, which is not worth the loss. Moreover, the cavitation at the bottom of the cleaning cylinder vibration plate is severe, and the water point corrosion will also increase. When using organic solvents such as trichloroethylene, there is basically no problem, but when using water or water-soluble cleaning solutions, it is easy to suffer from water point corrosion. If the surface of the vibration plate has been damaged, cavitation corrosion will be more severe under high power, so the ultrasonic power should be selected according to the actual use situation.

3、 Selection of cleaning solution temperature

The suitable cleaning temperature for water cleaning solution is 40-60 ℃, especially in cold weather when the temperature of the cleaning solution is low and the cavitation effect is poor, the cleaning effect is also poor. Therefore, some cleaning machines wrap heating wires around the outside of the cleaning cylinder for temperature control. When the temperature rises, cavitation is prone to occur, so the cleaning effect is better. As the temperature continues to rise, the gas pressure inside the bubble increases, causing a decrease in the impact sound pressure, reflecting the synergistic effect of these two factors.

4、 Use of cleaning basket

When cleaning small items, a mesh basket is often used. Due to the ultrasonic attenuation caused by the mesh, special attention should be paid to using a mesh size of 10mm or more.

5、 Determination of the amount of cleaning solution and the location of cleaning parts

It is preferable for the liquid level of the cleaning solution to be higher than 80mm above the surface of the vibrating element. Due to the influence of standing wave field, the amplitude of the single frequency cleaning machine is small at the nodes and large at the amplitudes, resulting in uneven cleaning. Therefore, the location for cleaning items should be placed at the wave amplitude.

6、 Different cleaning solutions, different cleaning systems to distinguish

Water based system: usually composed of an open groove in which the workpiece is immersed. The complex system consists of multiple tanks and is equipped with a circulating filtration system, spray tank, drying tank, and other accessories.

Solvent system: mostly ultrasonic vapor phase degreasing and cleaning machines, often equipped with continuous waste liquid recovery devices. The ultrasonic vapor phase oil removal process is completed by an integrated multi tank system formed by a solvent evaporation tank and an ultrasonic immersion tank. Under the combined action of hot solvent vapor and ultrasonic agitation, oil, grease, wax, and other dirt dissolved in the solvent are removed. After a series of cleaning processes, the workpiece is heated, cleaned, and dried.

7、 Ultrasonic cleaning process and selection of cleaning solution

Before purchasing a cleaning system, the following application analysis should be conducted on the cleaned parts: clarify the material composition, structure, and quantity of the cleaned parts, analyze and clarify the dirt to be removed. These are all prerequisites for determining what cleaning method to use and whether to use water-based cleaning solution or solvent. The cleaning process still needs to be validated through cleaning experiments. Only in this way can suitable cleaning systems, well-designed cleaning processes, and cleaning solutions be provided. Considering the influence of the physical properties of cleaning solution on ultrasonic cleaning, temperature, surface tension, viscosity, and density should be significant influencing factors. Temperature can affect these factors, so it can also affect the efficiency of cavitation.

8、 Cleaning parts processing

Another consideration for ultrasonic cleaning is the design of the loading and unloading of the cleaning parts or the placement of the cleaning fixtures. When the cleaning parts are in the ultrasonic cleaning tank, neither the cleaning parts nor the cleaning basket should touch the bottom of the tank. The total cross-sectional area of the cleaning parts should not exceed 70% of the cross-sectional area of the ultrasonic groove. Rubber and non rigid plastics absorb ultrasonic energy, so caution should be exercised when using these materials for fixtures. Special attention should also be paid to cleaning insulated components. Improper design of the tooling basket or excessive weight of the workpiece can greatly reduce the efficiency of even a good ultrasonic cleaning system. Hooks, shelves, and beakers can all be used to support cleaning items.