3. Wheel welding

3.1 Principle

Roller seam welding differs from spot welding in that conventional electrodes are replaced by copper discs, or rollers, which are rotated to produce continuous, sealed lap welds.

Welding is carried out progressively and continuously, combining sheet clamping and current flow, along the entire length of the bead to be produced.

A welding cycle therefore comprises the following phases, similar to those for spot welding:

• docking: the two knurled wheels clamp the two parts to be welded at the starting point, docking them and locating the current;

• welding: the current flows, triggered by the closing of the primary contactor, and the rotation of the...