PRO-POINT 8611311 Manuel D'utilisation page 16

8611311 180 MULTI-PROCESS MIG-ARC-TIG WELDER V1.0
WIRE FEED ROLLER SELECTION
This welding machine includes two V-groove drive rollers.
The importance of smooth, consistent wire feeding during MIG welding cannot be emphasized
enough. The smoother the wire feed, the better the weld.
Feed rollers, also called drive rollers, are used to feed the wire mechanically along the length of
the welding gun.
Feed rollers are designed 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 (Fig. 22-1) is
held in the groove by the top roller of the wire drive unit and is referred to as the pressure roller
(Fig. 21-2). Pressure is applied
21-2
by a tension arm that can be
adjusted to increase or
21-1
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
V-Groove U-Groove Knurled-Groove
obtain optimum wire feed.
Fig. 21
V-Shaped Groove - Solid hard wire, like 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. Solid wires are more forgiving to feed due to their higher cross sectional column
strength. They are stiffer and don't bend easily.
U Shaped Groove - Soft wire, like Aluminum, requires a U-shape groove. Aluminum wire has
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 torch's inlet guide tube. The
U-shaped roller offers more surface area grip and traction to help feed the softer wire. Softer
wire also requires 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.
Knurled Drive Roller - Flux core/gasless wire is made up of a thin metal sheath that has fluxing
and metal compounds layered onto it and is 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. A
knurled drive roller was developed with 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 of using a
knurled wire feed roller with flux cored wire is it will slowly eat away at the surface of the welding
wire over time. These small bits eventually dislodge and go down into the liner. This will clog the
liner and the added friction 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.
OPERATION
FEATURES
THERMAL OVERLOAD PROTECTION
Constantly exceeding the duty cycle can damage the cutting unit. An internal thermal protector
will open when the duty cycle is exceeded, shutting OFF all cutting unit functions except the
cooling fan. Leave the cutting unit turned ON with the fan running. The thermal protector will
automatically reset and the cutting unit will function normally again once it has cooled.
Wait at least another 10 minutes after the thermal protector opens before resuming cutting.
Starting before this additional time may result in a shortened duty cycle
16 For technical questions call 1-800-665-8685