Spot welding is a process to join two metal surfaces together. This process makes use of the heat that is generated from the resistance to the electric current that flows through the metal pieces. The two work pieces are held together with the help of electrodes. These electrodes are most commonly copper alloy electrodes. The copper alloy electrodes are used to concentrate all the electric current onto a single spot which creates a weld.
The weld is formed by the melting of the spot where a large amount of current is concentrated upon. The reason why spot wielding is favored is because a lot of current is concentrated on a single spot which creates a quick weld. A relatively less amount of time is taken for the joining of the two metals. The permits the welding of the two metals without heating up the rest of the sheet excessively.
The amount of energy or heat that is delivered to the spot is determined by the duration of the weld as well as the amplitude of the current that is used. A stop weld will increase the hardness of the material. The basic components of a spot welding machine would include a welding transformer, welding electrodes, capacitor banks, and switches.