Both MIG (metal inert gas) and MAG (metal active gas) welding create heat between metal pieces and a wire electrode to form a joint. The difference is the type of gas used to shield the weld area (pool). MIG employs inert gases (argon and helium) and is mostly used for work with non-ferrous metals like aluminum. MAG uses active gas (mixtures of argon, carbon dioxide and oxygen) to weld steel. These processes are very versatile and can be used in most situations.

TIG (tungsten inert gas) welding is a more precise method for joining metals than MIG/MAG welding, with a welding arc formed between the workpiece and an electrode as filler wire is added manually. Due to lower heat exchange and better control, TIG welding is suited for use with thin metal and more challenging assemblies. It is, however, slower than MIG or MAG.

Robotic welding may employ any of the above welding types (MIG/MAG/TIG) but with the welding pistol positioned by a robot manipulator instead of a human hand. This type of welding is good when welding seams are numerous or long. Welding quality is stable and high speed can be achieved. Additional investment in tools may be required.

In this process, two or more sheet metal parts are held together by copper electrodes while electrical current between the electrodes melts the pieces together creating a join (“nugget”). This is one of the oldest and simplest welding methods. It’s a fast and a reliable way to weld two or more sheet metal parts together or to weld components (like a weld nut) to a sheet metal part. Other than that, though, its usage is very limited.