Ultrasonic frequency
Ultrasonic cleaning machine operating frequency is very low (in the human hearing range) will produce noise. When the frequency is less than 20kHz, the noise is not only large, but may be beyond the limits of the safety noise in occupational safety and health laws or other regulations. In applications requiring high power to remove dirt without considering the surface damage of the workpiece, the lower cleaning frequency is usually selected from the 20kHz to 30kHz range. Cleaning frequency in the frequency range is often used to clean large, heavy parts or high density material parts.
High frequency is usually used to clean smaller, more sophisticated parts, or to remove tiny particles. High frequency is also used to be used to the surface of the workpiece is not allowed to damage the application. The use of high frequency can improve the cleaning performance from several aspects. As the frequency increases, the number of cavitation bubbles increases linearly, so that more and more intense shock waves can be generated. If the power is kept constant, the cavitation bubbles become smaller, the energy of the release is reduced, so that the damage to the surface of the workpiece can be effectively reduced. Another advantage is that the high frequency of the viscous boundary layer (the Nouri effect), making the ultrasound can "find" very small particles. This situation is similar to the water level in the lower stream can see small stones at the bottom of the stream.
Choice of frequency of ultrasonic cleaning machine
There is a close relationship between the threshold of ultrasonic cavitation and ultrasonic frequency, the higher the frequency, the higher the cavitation valve. In other words, low frequency, the more prone to cavitation, and in low frequency liquid by compression and rarefaction has longer time intervals, the bubble before the crash can grow to a larger size, higher cavitation intensity, facilitates the cleaning effect. So low frequency ultrasonic cleaning is suitable for large parts of the surface or dirt and cleaning parts of the high degree of combination of occasions. However, it is easy to clean the surface of the cleaning parts, it is not suitable for cleaning parts with high surface finish, and the cavitation noise is high. About 40KHz frequency. In the same sound intensity, cavitation bubble number frequency is 20kHz much, strong penetrating power, should be cleaning the surface with complex shape or a blind hole in the workpiece, cavitation noise smaller, but cavitation intensity is low, suitable for cleaning dirt and cleaning surface binding force is weak. High frequency ultrasonic cleaning for computer, microelectronic components cleaning fine; MHz ultrasonic cleaning is suitable for integrated circuit chips, wafers and thin film wave cleaning, can remove micron, submicron dirt and cleaning without any damage. Therefore, from the cleaning effect and economic considerations, the frequency of the general choice in the 20 - 130KHZ range, of course, the correct choice of frequency is very important.
