What is the function of the drive rolls in the wire feed system?

• A. They regulate voltage.
• B. They grip and advance the welding wire toward the contact tip at a controlled speed.
• C. They hold the electrode in place.
• D. They provide shielding gas.

Answer: (B)

The drive rolls are responsible for gripping the welding wire and pushing it through the feeder and toward the contact tip at a controlled speed. In GMAW, a steady, adjustable wire feed is essential because it directly determines how much metal is deposited and how stable the arc remains. The rolls bite into the wire with adjustable tension to prevent slipping or crushing, and the rotation of the rolls sets the wire feed rate. This feed rate interacts with the welding current and voltage to control heat input, bead shape, and penetration. If the wire advances too quickly, you may trap too much metal or cause instability; if it’s too slow, insufficient deposition and poor arc stability can result. The other options aren’t the function of the drive rolls: voltage is controlled by the power source, the electrode is held by the contact tip and gun assembly rather than by the drive rolls, and shielding gas is supplied by the gas system.