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RAZOR COMPACT 250
OPERATING MANUAL
Wire Types and Sizes
Use the correct wire type for the base metal being welded. Use stainless steel wire for stainless steel, aluminium
wires for aluminium and steel wires for steel.
Using poor quality milled wire can result in poor performance and appearance. To ensure optimal performance
when welding, use standards approved wire such as UNIMIG HYPERMIG wire.
Use a smaller diameter wire for thin base metals. For thicker materials use a larger wire diameter and larger machine.
Check the recommended welding capability of your machine.
Refer to the welding guide located on the door inside the machine.
Drive Roller Selection
The importance of smooth, consistent wire feeding during MIG welding cannot be emphasised enough. The
smoother the wire feed, 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.
Drive 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 (V Groove)
Steel or 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.
Aluminium (U Groove)
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 the 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, causing feed issues.
Flux-Cored/Gasless Wire (Knurled/F Groove)
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/F
groove drive roller has been developed, and
it has small serrations in the groove. The serrations grip the wire and assist in driving it without too much pressure
from the top roller. The downside to the knurled wire feed roller on flux-cored wire is it will slowly 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.
V GROOVE
U GROOVE
F(Knurled) GROOVE
Size mm Part Number
0.6 - 0.8 0.6-0.8V30/22
0.8 - 1.0
0.8-1.0V30/22
0.9 - 1.2
0.9-1.2V30/22
1.0 - 1.2
1.0-1.2V30/22
Size mm Part Number
0.6 - 0.8 0.6-0.8U30/22
0.8 - 1.0
0.8-1.0U30/22
0.9 - 1.2
0.9-1.2U30/22
1.0 - 1.2
1.0-1.2U30/22
Size mm Part Number
0.8 - 0.9 0.8-0.9F30/22
0.9 - 1.2
0.9-1.2F30/22
Roller Diameter Size: 30/22
V Groove Roller (Steel Wire)
U Groove Roller (Aluminium Wire)
Knurled/F Groove Roller
(Flux-Cored Wire)
RAZOR Compact 250 Manual APR23.indd 29
RAZOR Compact 250 Manual APR23.indd 29
6/04/2023 4:03:08 PM
6/04/2023 4:03:08 PM
