Why can high frequency cleaning avoid damage to the workpiece?

Update time:23-01-2021
Summary:

Why can high frequency cleaning avoid damage to the wor […]

Why can high frequency cleaning avoid damage to the workpiece? Everyone knows that the basic principle of ultrasonic cleaning is based on the cavitation effect of liquids. Cavitation effect
The intensity of the response is directly related to the frequency. The higher the frequency, the smaller the cavitation bubble and the weaker the cavitation intensity, and the degree of weakening is very large. For example, if the cavitation at 25KHz
The intensity is compared to 1, the cavitation intensity at 40KHz is 1/8, and at 80KHz, the cavitation intensity drops to 0.02. So if the frequency is selected correctly, the ultrasonic damage to the workpiece
The problem does not exist.

It can be seen that the ultrasonic cavitation threshold is closely related to the frequency of ultrasonic waves. The higher the frequency, the higher the cavitation valve. In other words, the lower the frequency, the easier it is to produce cavitation,
Moreover, the compression and thinning effect of the liquid has a longer time interval under low frequency conditions, so that the bubble can grow to a larger size before collapse, and the cavitation strength is increased.
Conducive to cleaning. Therefore, low-frequency ultrasonic cleaning is suitable for occasions where the surface of large parts or the surface of the cleaning part is highly bonded. But it is not easy to corrode the surface of the cleaning part
It is advisable to clean the parts with high surface finish, and the cavitation noise is loud. At a frequency of about 40 KHZ, under the same sound intensity, the number of cavitation bubbles generated is more than when the frequency is 20KHZ.
Strong penetrating power, suitable for cleaning workpieces with complex surface shapes or blind holes, cavitation noise is small, but the cavitation strength is low, suitable for cleaning the adhesion of dirt and the surface of the cleaned part
Weak occasions.

Selection of ultrasonic power:

When the sound intensity increases, the ratio of the maximum radius of the cavitation bubble to the initial radius increases, and the cavitation intensity increases, that is, the higher the sound intensity, the stronger the cavitation, which is beneficial to ultrasonic cleaning.
Washing effect. But it’s not that the larger the ultrasonic sound power, the better. If the sound intensity is too high, a large number of useless bubbles will be generated, which will increase the scattering attenuation and form a sound barrier. At the same time, the sound intensity will increase.
Will increase non-linear attenuation, which will weaken the cleaning effect far away from the sound source. Therefore, the effect of ultrasonic cleaning is not necessarily positive with the applied power and working time.
Compared with, sometimes it takes a long time with low power to remove the dirt, and if the power reaches a certain value, the dirt may be removed quickly.

If the ultrasonic power is too large, the cavitation intensity of the liquid will be greatly increased at this time, and the more precise parts will produce pits, and the water pitting will also increase. If the surface of the vibration plate has been affected

In the case of cavitation corrosion, the cavitation corrosion at the bottom of the water under strong power is more serious, which reduces the life of the equipment and causes unnecessary losses. At the same time, the cavitation of the vibrating plate at the bottom of the cleaning tank is also very serious.

Seriously, shorten the life of the cylinder.

However, the choice of ultrasonic cleaning power is small, and it takes a long time to remove the dirt, which is not desirable. Conventional ultrasonic cleaning in the industry, the standard ultra

The sonic cleaning machine ranges from 100W to 1500W. The size of the workpiece depends on the size of the ultrasonic cleaning tank and the size of the ultrasonic cleaning tank determines the power of the ultrasonic. In view of the fact that the current sound intensity measurement technology of the reverberation field is not mature enough, the power per unit area is still used for design. Generally, the output power density of a standard ultrasonic cleaner

Most of them are around 0.3 to 0.6 watts/cm2, of course, this is just a normal situation. Pulse focused ultrasonic cleaning can be higher.Ultrasound equipment

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