1. Welding basics

1.1 Interface phenomena. Elements of physics

Welding is a technique for joining materials by fusion, involving a process of adhesion by molecular interdiffusion.

According to theory, the process of welding two polymers can be broken down into five stages:

• fusion of surfaces to be welded ;

• approaching and contacting the two surfaces ;

• surface "wetting";

• macromolecule diffusion and entanglement ;

• solidification of melts.

On contact with the heating element, the material is brought into a "softened" state.

The appearance of...