What are the methods to improve the cleaning effect of ultrasonic cleaning machine?Date: 2022-09-17Number: 209
Ultrasonic cleaning process selection mainly refers to the selection of cleaning fluid configuration, the form of ultrasonic cleaning, cleaning fluid environmental temperature, ultrasonic frequency, ultrasonic power and cleaning time and other factors of the selection.
Choosing a cleaning fluid suitable for oneself has a great influence on the actual effect of ultrasonic cleaning, because the basic principle of ultrasonic cleaning is usually cavitation effect, therefore, the choice of cleaning fluid in addition to their own raw materials, oil stains or impurities, but also must consider the choice of cleaning fluid viscosity to low, low interfacial tension, in order to facilitate the cleaning fluid cavitation. In the case of very strict cleaning quality, several different types of cleaning fluid are often selected, slot or sequential ultrasonic cleaning, and the efficacy of each cleaning fluid is different, such as optical parts cleaning choose trichloroethene, sodium hydroxide water solution synthetic detergent, water and alcohol lamp cleaning fluid.
The more common method of ultrasonic cleaning is to soak the tank body. The products are immersed in the tank body which is filled with a cleaning fluid and the ultrasonic vibration generated by the Ultrasonic transducer is radiated into the cleaning fluid for cleaning. This is especially suitable for small and medium-sized products. For products with large specifications and net weight, partial cleaning method can be adopted. Part of the product to be soaked in cleaning solution for cleaning, and part of the unwashed part to be soaked in the cleaning solution for cleaning after cleaning is completed, until thoroughly washed. Another method is to modify the Ultrasonic transducer into a unique shape to achieve partial cleaning according to the shape of large products and part of the requirements of partial cleaning. Different cleaning solutions are used for products that are strictly cleaned, in addition, it can be used with other cleaning methods, such as heating, soaking and ultrasonic cleaning for electronic components. For very thick oil, thick products, but also often choose high-temperature immersion or high-temperature spray washing, and then use ultrasonic cleaning multi-step cleaning method. For the complicated structure of items, such as the size of the hole concave angle of the products, can be taken to multi-frequency cleaning.
The ultrasonic vibration frequency of cleaning fluid is introduced, which has a great influence on the effect of ultrasonic cleaning. This is because the ultrasonic frequency has an effect on cavitation effect, at about 20 khz, the cavitation effect is favorable, and the actual effect of cleaning is obvious, but the requirements for Surface finish are higher, with smaller diameter holes or slits, and the optimum wavelength is shorter, the frequency of high-frequency ultrasonic cleaning is about 800 khz, but the high-frequency ultrasonic vibration loses more in the cleaning fluid, the efficiency distance is shorter, the cavitation intensity is also weak, and the cleaning efficiency is lower, moreover, some parts of the products can not be cleaned because of the shadow area caused by the specificity of high frequency. When using the ultrasonic cleaning equipment without frequency tracking, it is often necessary to adjust the frequency knob of the generator, make its input signal frequency and the natural vibration frequency of the transducer, this time cavitation is the strongest, in the transparent liquid can be seen in a lot of white convergence, hand test like acupuncture feel.
In order to ensure the efficiency of ultrasonic cleaning. Usually choose relatively high power, but too high power because of the cavitation effect is too strong to cause the surface of the product corrosion (that is, cavitation erosion) , damage to the product, this has a variety of coating or aluminum and aluminum alloy products is particularly obvious, excessive increase in power because of saturation effect also has no practical effect. For the products with serious oil stain, complicated shape and deep hole blind hole, the cleaning trough is deep, the viscosity of cleaning fluid is high, and the power of high frequency ultrasonic cleaning is high, when rinsing with water or alcohol, the power can be reduced.
Because the cavitation effect of cleaning fluid is related to the ambient temperature, the increase of temperature is beneficial to cavitation, but as the vapor pressure also increases, the cavitation effect decreases when the ambient temperature exceeds a certain value, it is therefore necessary to maintain an adequate ambient temperature. For example, water-based cleaning solutions are generally at about 45 â ° C, trichloroethene cleaning solutions are at about 75 â ° C and water is at about 60 â ° C, for easy evaporation flammable cleaning fluid can not be too high ambient temperature.
The performance and quality of ultrasonic cleaning is also related to the time of ultrasonic cleaning. The time is too short to reach the quality standard of cleaning, but the time is too long, and because the surface of the product cavitation corrosion and thus affect the quality, more serious oil stains, complex shape of the product cleaning should be longer, with a variety of coating products, aluminum and aluminum alloy products should not be too long cleaning. For products with relatively high Surface finish, under normal circumstances, the oil stains are relatively small, and the cleaning time should not be excessive. The actual time should be determined through experiments.
In order to ensure the actual cleaning effect and the normal operation of the ultrasonic cleaning equipment, the position of the cleaned products in the cleaning tank should be paid special attention to, so that the radiation surface can not occur the expected vibration, and then the cleaning device can not reach the normal working environment, which is relatively large net weight of products is essential. The product should be suspended in the cleaning tank and as close to the radiation surface as possible using common tools. Secondly, the focus of cleaning part of the point to the ultrasonic source. Third, the waste should be considered to be washed down to be able to discharge products smoothly. Fourth, to facilitate the convection of cleaning fluid in the cleaning tank. In the selection of cleaning fluid reuse and continuous filling efficacy of the method, the rate of leakage can not be too fast, or because the filling of the cleaning fluid contains too much gas, will weaken the cavitation effect.
For blind hole cleaning, first fill the blind hole with cleaning fluid, then point down the blind hole to the ultrasonic source, in the cleaning process, must always keep the hole filled with cleaning fluid, to obtain significant results.
Ultrasonic cleaning tank should be avoided as far as possible collision and when hot and cold, to prevent damage it and the transducer connection.
There are some sharp choice of ultrasonic cleaning, the need to degaussing, or the rust residue is not easy to clean.
Ultrasonic cleaning quality inspection similar to other cleaning methods are the same, the key inspection after cleaning products surface stains residue.