Spot welding joint is one type of electric resistance welding. Generally joining
the sheet to sheet, sheet to rolled sections, wire to wire etc. by this spot weld
process. The spot welding is very effectively, which can replace the rivet joints
and is very speedy process, this spot welding machine does not need skilled operator,
it can be operated by semi-skilled labour.
The principle of spot weldingis shown in the bellow diagram. In this machine basically
having a transformer core (T) which is having a primary winding (PW). This primary
winding tapped at a number of points. The secondary winding (SW)
has the two ends of a circuit (C) which is connected two arms made of copper or bronze.
Each side has a copper electrode, this electrode of spot welding produce the sufficient
heat to fuse the joining metal. The lower arm is generally stationary and upper arm
is movable (upward and downward). The technical terms are rocker arms or electrode
arms. The electrodes of spot welding is cooled by water, the water is passing through
the inter looped water line.