It is generally considered that thermoplastic welding is irreversible. A few processes such as induction welding can produce reversible assemblies. As to which method to choose should be made at the beginning of the product design, because the welding method may be important to the requirements of the part design, and different welding methods have obvious differences.


Hot gas welding technology is usually used to weld plastic pipes, sheets or semi-finished products rather than injection molded parts. However, many thermoplastic molded parts, especially the thermoplastic automobile disc, are repaired by hot gas welding technology. In addition, hot gas welding is sometimes used to prepare plastic sample parts.


Ultrasonic welding machine


The most common method of welding thermoplastic parts is ultrasonic welding. In this method, low amplitude and high frequency (ultrasonic) vibration energy is used to make the surface and molecular friction produce the heat required for welding the plastic parts of the pad. (sinusoidal ultrasonic vibration)


Ultrasonic welding occurs in the frequency range of 20-50 kHz, and the general amplitude range is 15-60um. At frequencies as low as 15KHz (higher amplitude), it is sometimes used for larger parts or softer materials. The welding process usually takes place in 0.5-1.5s. Welding process parameters include welding time, welding head position and welding pressure. Ultrasonic welding equipment is usually used to weld small and medium-sized thermoplastic parts, while large parts can be welded by multi-point welding.