Ultrasonic Plastic Welding

Process Description

Ultrasonic plastic welding technology is a fusion welding technology. The principle of this technology is to convert friction and vibrational energy into heat. The high-frequency vibration generated by the ultrasonic system is transmitted under pressure by a welding mold (referred to as a welding head) to the component to be joined, which causes relative vibration of the joint. Friction heat causes micro-melting, micro-melting hinders vibration, absorbs vibration energy and converts it into heat, which eventually causes the weld profile to melt in a very short time, thereby forming a polymer compound. In general, the welding profile of the plastic part to be welded must conform to the requirements of the respective material type and seam.

When ultrasonically sealed, the heat required is only produced in the thermoplastic sealing layer. The contours can be used to concentrate energy, so the sealing time is extremely short. When ultrasonically sealed, heat is generated inside the film. Therefore, it is not necessary to supply heat from the outside. The mold remains cold during the welding process. The heat generated in the product is extremely low. A temperature balance is quickly achieved between the carrier layer and the sealing layer. This results in excellent thermal fusion strength.

Vertical technology

This is the most common method of welding plastic parts using ultrasonics. Generally, the entire welding system is longitudinally aligned, and the vibration is applied longitudinally to the workpiece; the pressure generated by the cylinder pushes the welding shaft of the entire system to force the workpiece to the upper layer.

Torsion technique

The system is also a complete vertical structure, but the welding process is completely different. This method is a high frequency friction welding. Application of vibration tangential: The welding head moves between the upper and lower workpieces. The high vibration frequency (20 kHz), amplitude and pressure cause fusion between the two workpieces due to friction.

Application range

Ultrasonic plastic welding is capable of welding all thermoplastics. Of particular note is the geometrical combination of different crystalline plastic parts to weld different crystalline types of plastic.

The welded structures in the longitudinal and torsional methods are completely different.

Ultrasonic welding can connect different types of thermoplastics (amorphous plastics) to some extent, but ultrasonic welding is not suitable for welding thermoset plastics.

Today, ultrasonic welding has been widely used in the plastics processing industry.

Customer advantage

The best process for a specific application (longitudinal or torsional process)

 "Torsion welding" innovation

 Fast work

 Continuous process monitoring guarantees consistently high quality

 Reliable connection

 Sealed connection even with product residue