What is ultrasound? What is the principle of ultrasonic cleaning?
Date: 2022-09-15Number: 209
What is ultrasound? What is the principle of ultrasonic cleaning?
Ultrasonic wave is higher than the range of human open hearing. The frequency of a sound wave determines its pitch. Frequencies above 18 khz are generally considered ultrasonic. The frequencies used for ultrasonic cleaning range from 20,000 cycles per second or kilohertz (KHz) to more than 100,000(KHz) . The frequency commonly used in industry is between 20 khz and 50 khz. Frequencies in excess of 50KHz are more commonly found in low-power applications such as small desktop ultrasonic cleaners.
The principle of the ultrasonic cleaning machine is that the high-frequency oscillating signal emitted by the ultrasonic generator is transmitted to the medium-cleaning solvent through the conversion of the transducer into a high-frequency mechanical oscillation, tens of thousands of tiny bubbles are formed and grow in the negative pressure region of ultrasonic longitudinal propagation, but quickly close in the positive pressure region. In a process known as“Cavitation,” the bubbles close, creating an instantaneous high pressure of more than 1,000 air pressures, continuous instantaneous high pressure is like a series of small“Explosions” constantly impact the surface of the object, so that the surface of the object and the cracks in the rapid exfoliation of dirt, so as to achieve the object surface purification.
Does the ultrasonic cleaning system work?
There is no universal quantitative standard for evaluating whether an ultrasonic cleaning system is working properly, the commonly used methods are the“Aluminum foil test” and the“Graphite slide test”, and some of the hydrophone test methods. All of the above methods are used as relative tests. In the actual test process because of the temperature test water level cleaning fluid and other factors affecting the test results only reference value. The product is equipped with a visual two-color light-emitting strip level meter on the control panel of the equipment. The visual display setting and the relationship between the output current can be used as a reference for evaluating the working state of the ultrasonic system, as an alternative, it is necessary to know the working state of the ultrasonic system accurately, which is to detect the output power of the ultrasonic power supply and calculate the electromechanical conversion parameters of the transducer accurately.
What frequency is the workpiece used?
Different cleaning machines require different ultrasonic frequencies, and lower ultrasonic frequencies mean larger cavitation bubbles and more intense cavitation internal ruptures. Cavitation bubbles are smaller and more numerous at higher frequencies and although the rupture is less intense within cavitation. The lower the ultrasonic frequency, the more easily the cavitation in the liquid, and the stronger the force. It is suitable for rough and dirty first washing of workpiece. High frequency ultrasonic directional strong suitable for fine objects cleaning. With the increase of the working frequency, the noise of the ultrasonic wave is reduced obviously. The frequency commonly used in industry is 16,18,20,25,28,40 khz. The frequency selection needs to be determined according to practical experience and process test, and the wrong selection will cause a lot of trouble. For example, silicon wafers are cleaned at 28 khz
They tend to be broken, and 40 khz cleaning of ferrite permanent magnet materials often has little effect.
Points to note
1, ultrasonic cleaning machine power and electric heater power supply must have good grounding device.
2, ultrasonic cleaning machine is strictly prohibited without cleaning fluid boot, that is, cleaning cylinder without adding a certain amount of cleaning fluid, can not close the ultrasonic switch.
3. Do not open the heating switch when there is no liquid in the cleaning equipment with heating equipment.
4. Do not clean the bottom of the cylinder with a heavy object (iron) to avoid damage to the chip of the energy converter.
5, ultrasonic generator power supply should be used alone a way of 220V/50Hz power supply and install more than 2000W voltage regulator.
6, clean the bottom of the cylinder to wash regularly, not too much sundries or dirt.
7, each time when the new liquid, after the start of the ultrasonic, can be washed.
Ultrasonic cleaning machine is used in electronics, electrical parts, jade processing, watch machinery, automotive industry, aviation industry, medical industry, machinery, chemical fiber, plastic, metal products, optical glass and other industries.
In fact, it is everywhere in life. Eyes, including sunglasses, used for a long time lens spent need to clean, with ultrasonic cleaning machine; gold and silver jewelry, shoes bag metal accessories with a long dull luster, want to let it re-shine, with ultrasonic cleaning machine; What should we do if the disc and watch chain are dirty? Or use an ultrasonic cleaner. The Sonication occurs in a liquid, and all surfaces in contact with the surface of the liquid can be cleaned, no matter how complex the shape of the object, all the gaps will be cleaned. It will not cause wear and tear on objects, make your life easier and more convenient.