Spot welding is used for joining work pieces by a lap-weld. The joint obtained as a result
of forcing punches into the work pieces prepared for welding is called a weld spot. The
forcing of a punch can be done from both sides (see the upper part of the diagram) or from
one side (middle part of the diagram). Preliminary tightening of the pieces to be welded
(lower part of the diagram) ensures higher strength of a weld spot.
There are two basic methods of butt welding:
1. sequential welding of overlapping spots with uninterrupted welding of the seam.
The welding is done with rotating rollers (upper part of the diagram);