Introduction to Plastic Welding Methods

Plastic welding is a process that uses heat to melt the connection point of plastics and bond them together under a certain pressure. Plastic welding can use filler rods, or it can directly heat the workpieces without using welding materials.

In most engineering applications, it is required that the joint has the same performance as the base material. The welding method and welding technology have a significant impact on the joint performance.

Due to the different material properties of plastics and the different conditions of use, the methods used for welding are also different, mainly reflected in the different heating methods. In addition to mostly being related to the melting and flow characteristics of plastics, they may also follow their own unique mechanisms.

The welding methods for thermoplastic plastics can be broadly classified into three categories: hot welding, friction welding, and electromagnetic welding. Hot welding includes hot gas welding, hot press welding, extrusion welding, heated tool welding, and infrared radiation welding; friction welding can be divided into rotary welding, vibration welding, high-frequency welding, and ultrasonic welding; electromagnetic welding includes electric resistance welding, induction welding, capacitive welding, and pulse welding. Common plastic welding methods currently used include hot air welding, extrusion welding, and capacitive welding. Hot air welding has the longest history and is widely used, suitable for welding large equipment or components. Its disadvantage is that it can only be used for manual operation, and the production efficiency is low. Extrusion welding is a welding process developed in the 1960s after a series of technological improvements. It can greatly shorten the welding time when welding thick-walled plates and improve the welding strength.