The function of the welding head of the ultrasonic welding machine is to manufacture specific plastic parts to meet the requirements of the shape and processing range of the plastic parts. The transducer, welding head, and welding head are designed according to the half-wavelength of the working ultrasonic frequency, and the size and shape should be specially designed. Any change may lead to changes in frequency and processing effect, which requires professional production. Depending on the material used, the durability will vary. The materials suitable for ultrasonic transducers, horns and welding heads are: titanium alloy, aluminum alloy, alloy steel, etc. Due to the high-frequency continuous vibration of ultrasonic waves around 20kHz, the requirements for materials are very high, which is currently unacceptable in the industry. Ordinary materials.

Ultrasonic effect:

When ultrasonic waves propagate in the medium, due to the interaction between the ultrasonic waves and the medium, the medium undergoes physical and chemical changes, resulting in a series of mechanical, thermal, electromagnetic and chemical ultrasonic effects, including the following four effects:

1. Mechanical effect:

The mechanical action of ultrasound can promote liquid emulsification, gel liquefaction and solid dispersion. When a standing wave is formed in the ultrasonic fluid medium, due to the action of mechanical force, the small particles suspended in the fluid agglomerate in the nodes and form periodic accumulations in the space. When ultrasonic waves propagate in piezoelectric materials and magnetostrictive materials, the mechanical action of ultrasonic waves causes excitation of electrical polarization and induced magnetization.

2. Cavitation:

When ultrasonic waves act on the liquid, a large number of small bubbles will be produced. One of the reasons is that the local tensile stress in the liquid creates a negative pressure. The decrease in pressure makes the gas originally dissolved in the liquid supersaturate, and then escape from the liquid and become small bubbles. Another reason is that the strong tensile stress "tears" the liquid into cavities, called cavities. Even in a vacuum, liquid vapor or other gases are dissolved in the liquid in the cavity. The small bubbles formed by cavitation move, grow or burst with the vibration of the surrounding medium. When the liquid enters the bubbles, it will produce high temperature, high pressure and shock waves. The internal friction associated with cavitation will form charges in the bubbles and cause light emission due to discharge.

3. Thermal effect:

Due to the high frequency and high energy of ultrasound, it will produce obvious thermal effect after being absorbed by the medium.

4. Chemical effect:

The effect of ultrasound can promote or accelerate certain chemical reactions. For example, pure distilled water will generate hydrogen peroxide after ultrasonic treatment, the nitrogen in the water will generate nitrous acid after ultrasonic treatment, and the dye aqueous solution after ultrasonic treatment will change color or fade. These phenomena are always accompanied by cavitation. Ultrasound can also accelerate the hydrolysis, decomposition and polymerization of many chemical substances. Ultrasound also has a significant impact on photochemistry and electrochemistry. After ultrasonic treatment, the characteristic absorption bands of amino acids and other organic substances disappeared, indicating that cavitation changed the molecular structure.