Ultrasonic wave refers to the frequency range higher than the sound wave accepted by human hearing. Human hearing energy is often between 20Hz and 20kHz. Therefore, generally speaking, any sound wave with a frequency higher than 20Hz is called ultrasonic wave.
Ultrasonic welding of plastic parts is to weld the contacted plastic parts together through high-frequency vibration, which belongs to the category of physical vibration and will not cause radiation harm to the human body. However, when ultrasonic plastic welding is used, it will produce harsh working noise. The noise intensity varies according to the frequency. The noise of equipment with higher frequency is relatively small, and the noise of equipment with lower frequency is relatively large
If the ultrasonic welding machine is 15KHz, it will have an impact on the human body, mainly because tinnitus will occur when it is used for the first time, but so far there has been no more serious problem, so it can also be said to be relatively safe. Besides, if it is not safe, no one dares to produce it However, it is recommended to use ear screen when using 15KHz machine, so as to greatly reduce the impact on people. If possible, try to use machines above 20kHz.
How to prevent:
1. It is better to have a special room for the ultrasonic machine. When operating the machine, the operator should wear earplugs, which can effectively reduce the damage of noise to ears.
2. Try to use machines above 20kHz, so that the noise will be reduced.

3. Install the ultrasonic sound insulation cover to the machine. The ultrasonic sound insulation cover is designed to solve the noise problem, which can effectively reduce the noise generated during the welding of the machine.