1. Ultrasonic intensity
The effect of ultrasonic cleaning depends on the cavitation effect, but the generation of cavitation effect is related to the intensity of ultrasonic waves. Under normal circumstances, when the ultrasonic power per unit area exceeds 0.3 W, the greater the ultrasonic intensity, the more obvious the cavitation effect and the better the cleaning effect. In addition, according to different cleaning objects, select the appropriate ultrasonic intensity, for example, the ultrasonic strength can be lower when cleaning the circuit board, and the ultrasonic intensity can be higher when cleaning the mechanical parts.
2. Ultrasonic frequency
Cavitation effect is also related to the frequency of ultrasonic waves. There is minimum critical amplitude in the generation of cavitation, that is, cavitation decreases with the increase of frequency. At present, the working frequency of the ultrasonic cleaning machine is roughly divided into three frequency bands according to the cleaning object: LF ultrasonic cleaning (20~50 kHz), high frequency ultrasonic cleaning (50~200 kHz) and MHz ultrasonic cleaning (1000 kHz). Low-frequency ultrasonic cleaning is suitable for the surface of large parts or where the dirt and cleaning parts have high bonding strength. High frequency ultrasonic cleaning is suitable for fine cleaning of computers and microelectronic components, such as disk, actuator, read-write head, and LCD and Flat display microcomponents. Megahertz ultrasonic cleaning is suitable for the cleaning of integrated circuit chips, silicon wafers, and thin films.
3. Cleaning temperature
The cavitation is favored, when the cleaning temperature is increased. However, if the temperature is too high, the vapor pressure in the bubbles increases, and the cavitation strength decreases. Therefore, the choice of temperature must consider the effect on the cavitation strength and the chemistry of the cleaning solution. Each kind of liquid has a cavitationally active temperature, and the more appropriate temperature for water is about 60°C, at which point the cavitation is most active.