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Comparing Robotic FCAW and Robotic MIG Welding

Flux core and MIG are two types of robotic arc welding processes. Both forms of robotic welding are fundamentally similar to one another. Despite having similar processes there are some unique differences when these two robotic applications are compared.

Welding Processes

The methodology behind both FCAW and MIG applications is essentially the same. Both welding processes involve the use of a continuously fed wire electrode to the base metal, forming the welding arc. A power source supplies the current to the electrode to heat the arc, allowing the metals to melt and join together. The main differences between the two processes is the type of wire electrode used and the use of a shielding gas.

Flux core welding robots use a tubular welding wire electrode that is hollow. The exterior of the wire consists of metal while the interior contains the flux. MIG welding robots on the other hand use a solid wire electrode.

Since FCAW robots use a hollow wire with flux, they do not need to use shielding gas. Instead, the flux forms a protective barrier of the weld to shield it from atmospheric contaminants. MIG welding robots require the use of a shielding gas to prevent poor quality welds.

Welding Equipment

Since the processes for FCAW and MIG welding applications are similar, the equipment needed to automate each is also similar. The main robotic components needed will include an articulated robot, weld torch, robotic welding power supply, wire feeder, and safety equipment. Six axis robots that are ideal for either process include the FANUC Arcmate 120ic, Motoman MA1400, and the ABB 2400. The only differences will be that MIG robots require an external gas container to supply the shielding gas and the type of wire electrode.


Robotic flux core welding can only be used on non-ferrous metals. This means a FANUC M710ic/20L can weld copper, stainless steel, and mild steel using flux core. MIG welding robots are capable of welding both non-ferrous and ferrous metals, allowing for greater welding flexibility.

When it comes to welding dirt, rusty, or painted metals, robotic FCAW has the advantage. MIG robots can only weld clean metal surfaces. Robotic FCAW also has the edge over robotic MIG when it comes to welding thick metal workpieces. MIG robots are better suited for thin metal welding. In most cases, used FANUC robots for sale that were in MIG applications will include the welding supply, wire feeder, and torch.

Weld Quality

Both forms of welding automation produce strong welds, however, MIG is considered to produce better quality. Robotic MIG welders produce less spatter during the welding process. This results in an aesthetically pleasing weld. In addition, the weld slag is easier to remove with robotic MIG applications, resulting in the appearance of a clean weld which is beneficial for welds that will be visible. Popular used industrial robot models for these applications include the FANUC Arcmate 100ic and the Motoman HP20.

The flux used in robotic FCAW causes more slag and spatter to be produced during welding. Removing these from flux core welds can be time consuming and result in a poorer weld appearance.


Determining which robotic welding method is cost-effective is not a straight forward answer. The wire electrode for FCAW is more expensive than the one used for MIG welding. However, since MIG requires a shielding gas, the expense of purchasing the tank and gas itself may make the costs of each closer than they would initially appear. These are important items to consider when choosing to automated with industrial robots.

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