Spot welding directs a large current to a specific point between two metal surfaces to produce a weld in a short time period. This type of welding requires great precision and is used extensively in automated assembly processes, especially for manufacturing automobiles. The weld time and current used for spot welding depend primarily on the thickness and type of metal you are welding.
Use a pair of electrodes to clamp the work pieces together and deliver the current needed for the weld. Both electrodes focus current at the same point to make a spot weld.
Draw a high current for spot welding, according to the thickness and type of medal. Spot welding may require up to 90,000 amperes for thick pieces of aluminum.
Maintain the current for a specific period of time. Weld times in spot welding can vary from 0.01 seconds to 0.63 seconds, depending on the metal thickness. Spot welding may be used on extremely thin pieces of metal, up to 1.25-inch metal plate.
Keep the electrodes in place while the welded metal cools. Spot welding electrodes have holes in their center which allows the work piece to cool more quickly. Spot welders use brine and water solutions to prevent them from overheating.
Release the work piece and wait for the next work piece to arrive on the assembly line. Repeat the spot welding process on the next work piece.