Fronius Feed Rolls FAQs
Straight answers to the questions people ask when choosing, fitting and looking after wire feed rolls for a MIG machine.
How do I match the roll to my wire diameter?
Each groove is made for a particular wire diameter, so the roll must match the wire you are feeding. A mismatch can cause slipping, an erratic arc or wire that is deformed or shaved on its way through.
The size is normally marked on the roll or listed in the machine's parts list, so check the manual for your feeder. Some rolls have a different groove on each face, so make sure the groove you want is on the outside, facing the wire, when you fit it.
What is the difference between two-roll and four-roll feeders?
A two-roll feeder has one pair of rolls gripping the wire and is common on lighter-duty machines. A four-roll feeder has two pairs, giving a larger area of grip, so less pressure is needed at any one point and the wire is less likely to be deformed.
Four-roll feeders are generally preferred for heavy industrial use and for soft wires, but two-roll feeders also feed a range of wires. This depends on the machine, so check the manual for the rolls your feeder takes.
How do I know when feed rolls are worn?
Feed rolls are wear parts and knurled rolls in particular wear out, so inspect them regularly. Worn rolls become less effective at moving the wire, so you may see erratic feeding or slipping even when the pressure is set correctly.
Do not simply tighten the pressure to cover slipping, as this can flatten the wire and wear the liner and tip faster. There is no fixed replacement interval, as it depends on the wire, the amount of welding and the settings.
My wire keeps slipping or birdnesting. Could it be the rolls?
It can be, but check the whole wire path. Look at whether the groove type and size match the wire, whether the rolls are worn and whether the pressure is sensible. Then check the parts after the rolls: a worn or dirty liner, a contact tip that is the wrong size and tight bends in the cable all add load.
A quick check is to see how smoothly the wire pulls through the torch with the pressure released. Heavy drag points to the liner or tip rather than the rolls, and a liner that needs force to pull wire through should be replaced.