Kemppi Individual Feed Rolls FAQs
Straight answers to the questions people ask when choosing, setting up and replacing individual wire feed rolls.
What do feed rolls do?
Feed rolls grip the welding wire and push it from the spool, through the feeder and down the torch cable to the contact tip. The wire is pushed by a driven roll working against a pressure roll, and the groove in the roll is what holds the wire.
Because they feed the wire the whole time you weld, the grooves wear and the wrong roll type or size causes slipping, a flattened wire and an unstable arc. Choosing the right roll matters as much as choosing the wire.
Which groove type do I need for my wire?
It depends on the wire. V-groove rolls suit solid steel and stainless wire. Knurled V-groove rolls, which have small teeth to grip, suit flux-cored and metal-cored wires. Smooth U-groove rolls suit aluminium and other very soft wires. A U-cogged type exists for very soft cored wires.
The wrong type either slips or bites into the wire. Check the wire maker's recommendation and your machine manual before ordering.
How do I match the roll to the wire diameter?
The groove must match the wire diameter. A roll made for thicker wire will not grip a thinner wire and the wire will slip, while a roll that is too small can crush it. For example, a 0.9 mm wire needs a roll marked for 0.9 mm.
Check the size on the roll, the wire spool and your machine manual. If you are replacing a roll, read the size stamped on the old one, or the machine manual, and match the roll type to your wire as well.
What is a dual-size roll, and which groove is in use?
Some rolls have a groove on each face for two different wire sizes, for example one for 0.8 mm and one for 1.0 mm. The groove on the side facing the wire is the one in use, so the roll must be fitted with the correct size outward.
Fitting it the wrong way round can over-grip the wire and deform it, or cause slipping. Check the markings on the roll and the machine manual each time you change wire size.