What type of welding process typically employs a variable speed wire-feeder?

MIG (Metal Inert Gas) welding typically employs a variable speed wire-feeder because this process relies on a continuous supply of filler material that is fed through a welding gun. The wire-feed speed is crucial to controlling the amount of filler material that is deposited during the welding process, directly impacting the weld quality, penetration, and overall efficiency.

By adjusting the speed of the wire-feed, welders can manage the heat input and arc characteristics to match the requirements of the specific job and material being welded. This variable speed capability allows for greater flexibility and control, enabling the welder to adapt to different welding positions, materials, and thicknesses effectively.

This is in contrast to the other options: GTAW (Gas Tungsten Arc Welding) uses a tungsten electrode and typically does not require a wire feeder; FCAW (Flux-Cored Arc Welding) may use a wire feeder but often in a different context; and SMAW (Shielded Metal Arc Welding) relies on stick electrodes that are manually fed and do not involve a wire feeder. Thus, the use of a variable speed wire-feeder is characteristic of the MIG process.