Ultrasonic cleaning machines create a cavitation effect in the cleaning solution through high-frequency vibrations, resulting in efficient cleaning. Its core process is that the transducer converts electrical energy into mechanical vibrations, creating high-frequency sound waves that form tiny bubbles in the liquid medium. These bubbles rapidly expand and close violently under sound pressure, creating strong impact and local high temperatures to strip away contaminants attached to the surface of objects. This physical process allows ultrasonic cleaning to reach complex structures and subtle gaps that are difficult to achieve with traditional cleaning methods.
Frequency parameters
Frequency refers to the number of vibrations per second of ultrasonic waves, measured in kilohertz. The frequency selection directly affects the size, density, and penetration capacity of the cavitation bubbles. There is a clear physical relationship between frequency and cleaning effect, and the approximate relationship between cleaning intensity and frequency can usually be expressed by the following empirical formula: I ∝ P/f, where I represents the cleaning intensity, P is power, and f is frequency. This indicates that at the same power, the frequency increases, and the energy of a single cavitation bubble decreases.
Low-frequency ultrasound, such as in the range of 20 kHz to 40 kHz, produces cavitation bubbles with a larger size and stronger energy released when closed, making them suitable for removing stubborn dirt, large particles of impurities, or for handling workpieces with simple structures and hard materials. High-frequency ultrasound, such as 80 kHz to 120 kHz or even higher, produces smaller, denser, softer energy, but has strong penetration, can enter smaller gaps, is suitable for cleaning precision parts, optical components or items with high surface finish requirements, and can effectively reduce surface cavitation corrosion.
Power parameters
Power density refers to the ultrasonic power invested per unit of wash tank surface area or volume, usually measured in watts per liter or watts per square centimeter. It is a key energy factor that determines the strength of the cavitation effect. The higher the power, the better, but the frequency, the cleaning object and the cleaning solution. Sufficient power is the basis for maintaining a stable and strong cavitation effect. Insufficient power will lead to weak cavitation effect and poor cleaning effect; Excessive power can lead to excessive cavitation, leading to premature atomization of the cleaning fluid, wasted energy, and even damage to the surface of the delicate workpiece.
The choice of power should take into account the material of the workpiece, the nature of the dirt and the size of the cleaning tank. For greases and polishing pastes with strong adhesion, higher power density is required to provide sufficient energy for peeling; For dusty and loose particulate matter, medium power is sufficient. At the same time, power settings should be considered in tandem with frequency, and high-frequency cleaning often needs to match the appropriate power to maintain effective cavitation.
Frequency and power co-configuration
In real-world applications, frequency and power must be configured together to achieve specific cleaning goals. The selection of strategies is based on a systematic evaluation framework.
First, analyze the characteristics of the cleaning object, including the hardness of the material, the complexity of the geometry, the surface roughness, and the chemical composition and adhesion strength of the dirt. Secondly, adjust the parameters according to the different purposes of the cleaning stage (rough washing, fine washing). For example, to remove a large amount of heavy dirt in the pre-cleaning stage, lower frequency can be used with higher power; In the final rinse phase, fine cleaning and rinsing can be carried out at a higher frequency and at a moderate power.
The following is a reference guide to parameter configuration based on common cleaning tasks, demonstrating the synergistic relationship between frequency and power:
| Description of typical cleaning tasks | Recommended frequency range | Recommended power density range |
| Remove cutting oil and stubborn grease from metal parts | Low Frequency (25-40 kHz) | Medium to high (refer to specific equipment and volume) |
| Clean the circuit board and electronic connectors after soldering flux | IF (40-80 kHz) | Medium |
| Clean optical lenses, silicon wafers, and precision ceramics | High Frequency (80-120 kHz or above) | Low to medium |
| Laboratory glassware routine decontamination | Mid and high frequencies (40-100 kHz) | Medium |
In addition, the type of cleaning solution, temperature, and cleaning time are also key variables that affect the final effect, which need to be optimized together with ultrasonic parameters.
Operational recommendations
To ensure the cleaning effect and protect the workpiece, it is recommended to follow the following operating procedure: First, a cleaning test is carried out, using the same type of waste or representative sample to be cleaned, and a short test is carried out at a set frequency and power to observe the cleaning effect and the surface condition of the workpiece. Secondly, monitor the status of the cleaning fluid and replace or filter it regularly, because the contaminated cleaning fluid will attenuate the ultrasonic energy and affect the cavitation efficiency. Finally, the combination of parameters (frequency, power, time, temperature, cleaning fluid) for each successful cleaning application is recorded to establish standardized operating procedures for different tasks.
Optimization is a dynamic process. When poor cleaning results are found, systematic investigations can be made: Is the power sufficient to drive effective cavitation at the current frequency? Is the frequency suitable for the structural fineness of the current workpiece? Is the cleaning fluid temperature and chemical composition appropriate? By adjusting using the control variable method, efficient parameter windows for specific applications can be found.
Summary
The cleaning effect of ultrasonic cleaning machine is largely determined by the two core parameters of frequency and power. Frequency mainly determines the physical properties and depth of action of cavitation, while power provides the energy base required for cavitation. Understanding their respective influence mechanisms and synergistic principles is the prerequisite for the effective use of ultrasonic cleaning technology. In actual operation, there is no universal parameter setting, and it must be scientifically configured and optimized through tests in combination with specific cleaning objects, pollutant properties and process requirements, in order to achieve the purpose of clean and safe cleaning.