Ultrasonic Welding Principle:
Ultrasonic Welding Principle: When ultrasonic energy is applied to the thermoplastic surfaces to be welded, it generates several tens of thousands of high-frequency vibrations per second. This high-frequency vibration, with a certain amplitude, transfers the ultrasonic energy to the welding zone through the upper welding part. Due to the high acoustic impedance at the interface of the two welding surfaces, a localized high temperature is produced. Since plastics have poor thermal conductivity, the heat cannot be dissipated immediately and accumulates in the welding zone, causing the contact surfaces of the two plastics to melt rapidly. Applying a certain amount of pressure, they fuse into a single entity. After the ultrasonic energy stops, maintaining the pressure for a few seconds allows the material to solidify and take shape, forming a strong molecular chain and achieving the welding goal. The welding strength can approach the strength of the raw material. The quality of ultrasonic plastic welding depends on three factors: the amplitude of the transducer welding head, the applied pressure, and the welding time. The welding time and welding head pressure can be adjusted, while the amplitude is determined by the transducer and the variable amplitude rod. These three quantities interact to have an optimal value. When the energy exceeds this optimal value, the plastic melting amount increases, making the welded part prone to deformation. If the energy is too low, it is difficult to achieve a strong weld, and the applied pressure should not be excessive. This pressure is the product of the length of the welding part and the appropriate pressure per 1mm at the edge.
