The welding principle of ultrasonic mask spot welding machine is to convert 50/60 Hz current into 15, 20, 30 or 40 kHz electric energy through ultrasonic generator. The converted high-frequency electric energy is converted into mechanical movement of the same frequency again through the transducer, and then the mechanical movement is transmitted to the welding head through a set of amplitude modulator devices that can change the amplitude. The welding head transfers the received vibration energy to the joint of the workpiece to be welded. In this area, the vibration energy is converted into heat energy through friction to melt the plastic. The short pressure maintained on the workpiece after the vibration stops makes the two weldments solidify as a whole by molecular linkage. Generally, the welding time is less than 1 second, and the welding strength obtained is comparable to the body. Ultrasound can be used not only to weld hard thermoplastics, but also to process fabrics and films. The main components of a set of ultrasonic welding system include ultrasonic generator, transducer/amplitude modulator/welding head triplet, mold and frame.

To sum up, the ultrasonic spot welder used to weld the ear band of the mask is ultrasonic welding, so it is called ultrasonic mask spot welder.