Research shows that the use of ultrasonic spot welding machines in the plastic industry has become increasingly common around the world. Because the application of this technology can replace the flux, adhesive, fastener or other mechanical fixation methods required in the past production, the production efficiency is improved and the cost is reduced. The welding principle of the ultrasonic spot welding machine is that the generator generates 20KHz (or 15KHz) high voltage and high frequency signals. Through the energy conversion system, the signals are converted into high-frequency mechanical vibration, which is applied to the plastic workpiece. The temperature from the transmission point to the interface increases through the friction between the workpiece surface and the internal molecules. When the temperature reaches the melting point of the workpiece itself, the workpiece interface melts rapidly, and then fills the gap between the interfaces; When the vibration stops, the workpiece is cooled and shaped under a certain pressure at the same time to achieve perfect welding.