What is the principle of ultrasonic spraying?

Ultrasonic spraying is a method of spraying using ultrasonic atomization technology. Its principle is as follows:

1. Principle of ultrasonic atomization

    The ultrasonic generator generates high-frequency electrical signals, usually in the frequency range of 20kHz - 10MHz. These high-frequency electrical signals are converted into mechanical vibrations, which are realized by piezoelectric ceramic transducers. Driven by high-frequency electrical signals, the piezoelectric ceramic transducer will produce rapid mechanical vibrations.

    When the liquid is delivered to the surface of the transducer (usually the nozzle part), the vibration of the transducer is transmitted to the liquid. Due to the high frequency of vibration, capillary waves will be generated on the surface of the liquid under this high-frequency vibration. The capillary waves continue to develop, and when the energy of the vibration is large enough, the peaks on the surface of the liquid will be torn to form tiny droplets. The size of these droplets can be controlled by adjusting the frequency and power of the ultrasonic wave and the properties of the liquid (such as viscosity, surface tension, etc.). Generally speaking, the higher the ultrasonic frequency, the smaller the droplets produced.

2. Spraying process

    Once the liquid is atomized into tiny droplets, these droplets will be ejected from the nozzle under the impetus of the carrier gas (such as air, nitrogen, etc.), and then evenly deposited on the surface of the coated object. The flow rate and pressure of the carrier gas can also affect the effect of spraying. The appropriate carrier gas conditions can ensure that the droplets are evenly distributed on the target surface and can control the flight direction and speed of the droplets.

    Compared with traditional spraying methods, the advantage of ultrasonic spraying is that it can produce a very uniform droplet size distribution, which makes the coating after spraying more uniform and smooth. For example, in the coating preparation of electronic devices, the thickness and uniformity of the coating need to be precisely controlled. Ultrasonic spraying can meet this demand well because it can avoid problems such as droplet aggregation and sagging that may occur in traditional spraying. At the same time, since ultrasonic spraying is a relatively gentle spraying method, it can be used for spraying heat-sensitive materials or fragile materials to reduce damage to the materials.