Hybridization between Plasma and MIG Processes in a Tandem Configuration for Aluminum Joints

In this investigation the Plasma-MIG in tandem configuration is characterized by gradually bringing their torches closer together in order to observe the behavior of their electrical signals as the arcs are coupled. In addition, the Plasma process is configured with direct and alternating current, in order to observe the need for cathodic cleaning when the hybrid process is used in aluminum alloys. Once the phenomena that occur when hybridizing the processes are known, the interaction between the welding processes is studied, from an energy point of view. The objective is to observe if there is an exchange of current between the welding processes and, if it exists, how this affects the welding processes. The results showed that it is possible to couple the Plasma and MIG processes in a paraxial (tandem) configuration to make aluminum joints, with a stable arc and greater penetration than the single processes. The establishment of a "current path” between the MIG and plasma arcs was noticed, which allows the current flow between the welding process, influencing directly the MIG arc length behavior. Moreover, it was concluded that it is not necessary to configure alternating current in the Plasma process to weld aluminum, because the MIG process does the cathodic cleaning. It was also concluded that an external magnetic field is not necessary to stabilize the behavior of the welding arcs. The joints of 10 and 15 mm thickness presented good surface appearance, although the hybrid process demonstrated superiority only for the 15 mm thick joints.