What is ultrasonic welding? How to use in mask production
1. The principle of ultrasonic welding
Ultrasonic welding uses an ultrasonic generator to convert 50/60 Hz current into 15, 20, 30 or 40 KHz electrical energy. The converted high-frequency electric energy is again converted into mechanical motion of the same frequency through the transducer, and then the mechanical motion is transmitted to the welding head through a set of horn 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 by friction, which melts the plastic. Ultrasound can be used not only to weld hard thermoplastics, but also to process fabrics and films.
Second, the application of ultrasonic welding in the mask machine
The principle of multi-layer fusion of non-woven chemical fiber fabrics is to use high-frequency friction between contact surfaces to rapidly generate heat between molecules. Under a certain pressure, many woven fabrics or fabrics or PVC films can be welded together. The frequency usually used for welding of non-woven fabrics is 20KHz and 15KHz. Ultrasonic energy penetrates the materials to fuse them together. Generally, it is necessary to make tooth-like, net-like, and strip-like patterns on the welding head, form patterns on the surface of the fused product, and fuse multiple layers of fabric. Disposable flat masks and N95 masks are manufactured in this way, and the earbands of the masks are also spot welded by ultrasonic.
Three, system combination
Ultrasonic welding systems are generally used in automatic equipment, with automatic devices to complete continuous welding or reciprocating welding. Ultrasonic welding systems generally include: ultrasonic generators, ultrasonic transducers, ultrasonic welding molds (welding horn), and related accessories, such as flanges for fixed support of the transducer, connecting cables, etc.
Ultrasonic generator, also known as ultrasonic power supply, ultrasonic electric box, is an electronic circuit device that can provide high-frequency current, and can generate ultrasonic vibration energy with an ultrasonic transducer. The principle of ultrasonic transducers is to use the inverse effect of piezoelectric ceramics and add appropriate high-frequency current to the transducer to generate mechanical vibrations of the same frequency. Ultrasonic generator, ultrasonic transducer, and ultrasonic welding head constitute a complete set of ultrasonic vibration device. The three components of the ultrasonic vibration device must reach resonance before they can work normally. Improper installation and connection, improper resonance frequency, and improper adjustment will cause system abnormalities and damage the system in serious cases.
