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The importance of smooth consistent wire feeding during MIG welding cannot be emphasized enough.

Simply put the smoother the wire feed then the better the welding will be.

Feed rollers or drive rollers are used to feed the wire mechanically along the length of the welding gun.

Feed rollers are designed to be used for certain types of welding wire and they have different types of grooves machined in them to accommodate the
different types of wire. The wire is held in the groove by the top roller of the wire drive unit and is referred to as the pressure roller, pressure is applied by
a tension arm that can be adjusted to increase or decrease the pressure as required. The type of wire will determine how much pressure can be applied
and what type of drive roller is best suited to obtain optimum wire feed.

Solid Hard Wire

- like Steel, Stainless Steel require a drive roller with a V shape groove for optimum grip and drive capability. Solid wires can have more

tension applied to the wire from the top pressure roller that holds the wire in the groove and the V shape groove is more suited for this. Solid wires are

more forgiving to feed due to their higher cross sectional column strength, they are stiffer and don’t bend so easy.

Soft Wire

- like Aluminium requires a U shape groove. Aluminium wire has a lot less column strength, can bend easily and is therefore more difficult to

feed. Soft wires can easily buckle at the wire feeder where the wire is fed into inlet guide tube of the torch. The U-shaped roller offers more surface area
grip and traction to help feed the softer wire. Softer wires also require less tension from the top pressure roller to avoid deforming the shape of the wire,
too much tension will push the wire out of shape and cause it to catch in the contact tip.

Flux Core / Gasless Wire

- these wires are made up of a thin metal sheath that has fluxing and metal compounds layered onto it and then rolled into a

cylinder to form the finished wire. The wire cannot take too much pressure from the top roller as it can be crushed and deformed if too much pressure

is applied. A knurled drive roller has been developed and it has small serrations in the groove, the serrations grip the wire and assist to drive it without

too much pressure from the top roller. The down side to the knurled wire feed roller on flux cored wire is it will slowly over time bit by bit eat away at the

surface of the welding wire, and these small pieces will eventually go down into the liner. This will cause clogging in the liner and added friction that will

lead to welding wire feed problems. A U groove wire can also be used for flux core wire without the wire particles coming of the wire surface. However it
is considered that the knurled roller will give a more positive feed of flux core wire without any deformation of the wire shape.

V Groove

U Groove

Knurled Groove

Wire

Top Pressure Roller

22mm

30mm

10mm

| VIPER MIG 185 Manual

WIRE FEED ROLLER SELECTION

ROLLER DIAMETER: 30/22

V GROOVE DRIVE ROLLER - STEEL WIRE