**4. Applications of resistance spot welding**

Resistance spot welding is typically used when joining particular types of sheet metal, welded wire mesh, or bare wire mesh. Thicker sheets are more difficult to spot weld owing to the dissipation of heat into the surrounding metal more easily. Spot welding is possible with aluminum alloys, but their higher thermal and electrical conductivities necessitate larger welding currents. This necessitates the use of larger, more powerful, and more costly welding transformers.

Spot welding is most commonly used in the automobile manufacturing business, where it is nearly routinely used to join the sheet metals of car frames. Spot welders can also be fully automated and many of the industrial robots found on assembly lines are spot welders.

Spot welding is also utilized in orthodontist clinics to resize metal "molar bands" used in orthodontics with small-scale spot welding equipment.

To create batteries, spot welding is also used to attach straps to nickel-cadmium, nickel-metal hydride, or lithium-ion battery cells. Spot welding thin nickel bands to the battery terminals connect the cells. This method prevents the battery from overheating, which could occur if traditional soldering was used.

Some design practices must be followed for spot welding like connecting surfaces should be free of contaminants such as scale, oil, and dirt to ensure quality welds.
