Difference Between Robotic Arc Welding and Spot Welding
The two most common welding methods being automated by industrial robots are arc welding and spot welding. Nearly half of all active articulated robots are used for welding automation with the vast majority performing one of these two processes. Their popularity for welding automation is about the only thing they have in common as there are many differences between robotic arc and spot welding.
ApplicationRobotic arc welding is a form of liquid state welding, meaning metals are melted down in order to be joined together. There are several subtypes of arc welding that can be automated with robots. The main ones include MIG, MAG, TIG, PAW, FCAW, and SAW. The exact methodology will depend upon the specific arc welding application selected. The use of filler wire, shielding gas, consumable electrodes, and non-consumable electrodes varies with each process. In general, arc welding applications involve generating an electric arc from electricity in order to heat and melt metals. Once the metals have cooled, they are then permanently bonded together.
Spot welding is the opposite of arc welding as it is a solid state of welding, meaning metals are not completely melted. This robotic welding method creates concentrated welds at specific points on a workpiece, hence the name spot welding. Metal workpieces are clamped together to apply pressure. Heat is generated by resistance from the workpieces to an electrical current, which welds them together. Spot welding also goes by the name resistance welding. Unlike arc welding, spot welding does not have multiple subtypes of applications.
MaterialsArc welding robots can be used to weld most types of metals due to the multiple subtypes of arc welding applications. Arc welding applications can be used to weld both ferrous and non-ferrous metals. They can also accommodate most metal thicknesses. The FANUC Arcmate 120ic can weld both thin and thick metals using the automated plasma welding method. While the Yaskawa Motoman MA1440 is ideal for welding thick metals through robotic MIG welding.
Spot welding robots are more limited to the types of metals they can weld. Steel and stainless steel are the only types of metals recommended for robotic spot welding. Metal thickness is also limited to 3 mm. Most spot welding robots are used for welding sheet metal.