Selection of technical parameters for ultrasonic cleaning
The effect of ultrasonic cleaning is not necessarily proportional to the applied power and working time. Sometimes it takes a long time with low power to remove the dirt. But if the power reaches a certain value, the dirt may be remove quickly. If the ultrasonic power is too large, then the cavitation intensity in the liquid is greatly increase. The more precise parts will produce corrosion points, causing unnecessary losses. While cleaning the bottom of the cylinder vibration plate cavitation is also very serious, so that the cylinder life is shorten.
Another point: the ultrasonic power is too large. So that the liquid in the sound intensity is too high, will produce a large number of bubbles. In the acoustic surface to form a barrier, sound waves are not easy to radiate to the whole cylinder. Resulting in away from the source of the place cleaning effect is weaken. So choose the right sound intensity is a must. In view of the current reverberant field sound intensity measurement technology is not mature enough. At present or use the power per unit area to design. Generally a standard ultrasonic cleaner output power density is mostly select between 0.30.6w/cm2. As for continuous wave focused ultrasonic cleaning is generally select in a few dozen watts per square centimeter or so, pulsed focused ultrasonic cleaning optional higher.
1.Choice of operating frequency.
The operating frequency of the commonly use ultrasonic cleaner is between 20-40 kHz. Working frequency is low, in the use of water or water detergent cause by the cavitation of the physical cleaning force is obviously beneficial. But the cavitation-induced noise, noise decibels greatly exceed the relevant standards. So 20 kHz and below the frequency is rarely use, unless the noise reduction measures to keep up. For small gaps, slits, deep holes in the parts of the cleaning. Choose a higher frequency is better. Some foreign countries use several hundred kilohertz cleaning precision clock parts. For cleaning like silicon wafer surface of a few microns of tiny particles of dirt. Frequency optional in the range of megahertz.
2. Choice of cleaning baskets.
When cleaning small items, it is often necessary to use a cleaning basket But the mesh cage can cause ultrasonic attenuation. To change the mesh size after measuring the technical washing technique amount of transmittance results. From this, when the frequency is 28kHz, mesh size greater than 1mm or more is good.
3. Choice of cleaning fluid temperature.
The suitable cleaning temperature of water cleaning solution is about 40-60°C. And the relationship between mesh size and sound wave transmittance is especially in cold weather. If the cleaning fluid temperature is too low. The cavitation effect is poor, and the cleaning effect is not good. Therefore there are some cleaners in the cylinder set heating insulation control. If the temperature continues to rise. The gas pressure within the cavitation bubble increases, causing a drop in impact acoustic pressure. Which is detrimental to cleaning. It is seen that in a variety of different cleaning solutions. The cavitation strength of aluminum corrosion with temperature changes have an optimal value. Table 2 shows that in the same ultrasonic intensity and the same frequency. The same time, the relationship between the temperature of aluminum in different liquids and the amount of corrosion.
4. Choice of cleaning fluid volume.
The amount of cleaning fluid is generally 100mm higher than the surface of the vibrator, which is the best choice for the location of the cleaning item in the tank, but it varies according to the power of the cleaner. When the power is 600w, the liquid level can reach about 150mm. As a result of single-frequency cleaner by the impact of standing wave field, the amplitude at the wave section is very small, while the amplitude at the wave amplitude is very large, resulting in uneven cleaning, the best choice is the location of the cleane parts should be place at the wave amplitude, or make the items move up and down, so that the cleaning is uniform.
The basic components of ultrasonic cleaning equipment.
No matter the power of ultrasonic cleaning equipment, it is basically determined by the amount of cavitation corrosion of aluminum in different liquids/mg \ temperature water kerosene phenyl alcohol acetone 10 | cleaning technology cleaning technology cleaning technology The generator consists of three parts. Which is a large multi-tank cleaner also includes mechanical transmission device, cleaning fluid reflux filtration device, temperature control device, jet device and drying equipment, if the gas-phase ultrasonic equipment also includes a water chiller. If you use hydrocarbon solvent cleaning, vacuum and drying equipment is also require. Also known as cleaning tank. Cleaning cylinder size should be select according to the size of the ultrasonic power, if each 50w standard transducer for assembly, the bottom of the cylinder size basically to. 5w/cm2 for calculation, as for the depth should be considered above the height of the liquid, but also should be appropriate to meet the size of the cleaned parts requirements. Most of the cylinder material selection of stainless steel, thickness between 1.53.0mm, the bottom of the cylinder processing must be flat, but also need sandblasting treatment.