Spot welding: the technology
Spot welding creates strong joints by means of high pressure in a relatively small area and high energy in the form of electric current. The most important parameters for spot welding are:
During spot welding, the two welding electrodes press the components together. The weld current is then switched on. The contact resistance results in thermo-electrical heating and the material melts.
The current is then switched off. The molten material hardens, forming a joint that cannot be separated. The pressure must be maintained while the melt is cooling to avoid pore formation.