Spot welding
Resistance spot welding (RSW) is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current.
The amount of heat (energy) delivered to the spot is determined by the resistance between the electrodes and the magnitude and duration of the current.[3] The amount of energy is chosen to match the sheet's material properties, its thickness, and type of electrodes. Applying too little energy will not melt the metal or will make a poor weld. Applying too much energy will melt too much metal, eject molten material, and make a hole rather than a weld.[4] Another feature of spot welding is that the energy delivered to the spot can be controlled to produce reliable welds.