Tandem-MAG welding is an advanced development of conventional MIG/MAG welding and is used where high production rate is required as very fast travel speeds in welding is easily achieved. Although, the two wires work in same weld pool, the electrodes are insulated from each other in separate contact tube and the welding parameters for each are different and set independently but share common welding torch and gas nozzle. The penetration is controlled by the lead arc whereas the trail arc is responsible for bead. In order to straighten the wires, two wire feeders are required for unwinding from the drum coils and spools. Irrespective of the two electrodes, feeders, different parameters, the possibility is made to use just one arc and single wire for welding.
The advantage of Tandem-MAG welding is that in such hi-tech welding, the distortion rate of the work piece is relatively very low. But the ultra high speed lap welding and high deposition fillet welding in Tandem-MAG comes at a high cost which is a disadvantage thereby making the initial investment on the project higher and does not find economically suitable for small production units whereas conventional MIG/MAG can be incorporated in any production line at much lower cost than Tandem-MAG system and this is the reason, Tandem-MAG welding machines are more seen in European countries such as England, France, Germany and Italy but not many installations are found in all other countries.
In Tandem-MAG welding, the synchronized pulse current controls virtually the spatter and potential arc blow problems. Further, the high deposition rate for thin and thick plates is made possible and complex shape can be welded at high speed welding. For these reasons, this process is suitable for robotic welding.
The Tandem-MAG welding equipment works on GMAW automated process. The parameters for power are controlled independently and the synchronized wire feeders are installed separately. The two arcs are generated by two different electrodes in one single gas nozzle.
There are two variants of Tandem-MAG welding which are discussed below in detail.