During the epidemic, the demand for masks became great, and some enterprises turned to producing masks. In mask medical supplies, non-woven fabric is a better material. Its main components are pet, PP and PE, which are very suitable for ultrasonic welding. What is the welding principle of making masks?

Some indentations can be seen everywhere on the mask, such as edge banding, ear band and exhalation valve are ultrasonic welded.

In the production process of mask, we can intuitively understand the welding of all plastic nose bar, welding after folding, breathing valve welding, multi-layer roll welding and ear belt welding, which are actually completed by ultrasonic welding process.

When ultrasonic wave acts on the contact surface of thermoplastic plastics, it will produce tens of thousands of high-frequency vibration per second. This high-frequency vibration with a certain amplitude will transmit ultrasonic energy to the welding area through the upper weldment. Due to the large acoustic resistance at the interface between the two welding areas, local high temperature will be generated.

In addition, due to the poor thermal conductivity of the plastic, it can not be distributed in time at the moment and gathered in the welding area, resulting in the rapid melting of the contact surface of the two plastics. After adding a certain pressure, it will be integrated into one.

When the ultrasonic stops, let the pressure last for a few seconds to solidify and form, so as to form a solid molecular chain to achieve the purpose of welding, and the welding strength can be close to the strength of raw materials.

Non woven fabrics are used most in filtration, environmental protection and medical supplies industry. Like the sealing of liquid filter bag, the tail sealing is achieved by welding. After welding, it is waterproof and leak proof with high strength.