The major controls include the power switch (off/on
control), the wire feed potentiometer (speed control), and
the spool brake control (stops wire spool at end of
welding).
Auxiliary wire feeder controls may include:
• Mode switch. This control is used to select
various modes, such as spot, intermittent, and
seam welding.
• Trigger lock-in control. This control allows the
welder to weld without the need to depress the
operating switch during the entire operation.
• Burnback (anti-stick) control. This control
prevents the wire from sticking in the weld pool.
It sets the time that the arc power is on after the
stop switch is released to burn back the wire from
the molten weld pool. This control must be used
when spot welding.
• Spot weld time. This control sets the length of
time for the spot weld operation.
• Stitch weld time. This control sets the time needed
to make a long seam or a specific weld length.
• Prepurge timer control. This control establishes
the time that the gas will flow before welding will
start.
• Purge control. This control allows the welder to
open the gas solenoid. The amount of gas flow
can be set on the flowmeter, or the welder can
purge the gas lines prior to welding.
• Wire inching (jog) control. Moves the wire
through the wire feeder to the contact tip. It also
may be used by the welder when determining
wire speed. (Jog speed is the same speed as the set
wire speed.)
• Wire reel brake control. The reel brake control
should be adjusted so that the spool will stop
rotating at the same time the wire stops feeding at
the end of the welding operation. If the wire is
allowed to overspool and touch the feeder
housing, a short circuit may occur (if the
electrode circuit is energized), or the wire may
birdnest (tangle). The brake adjustment is a
tension device located in the hub of the wire
spool. When changing reels of wire, Figure 3-15,
always replace the reel locking pin, and check the
brake adjustment.
Wire Straightener
Wire straighteners are placed in the supply system to
reduce the amount of wire cast (curvature) before the
wire is drawn into the drive roller system. Excessive cast
is often found on hard wires, causing heavy wear of the
contact tips during welding. This can result in arc
outages (loss of arc). Increasing or decreasing the
amount of cast is done with an adjusting wheel on the
straightener. A three-roll wire straightener is shown in
Figure 3-16.
Wire Feeder Drive Roll System
The system for driving the electrode wire from the
spool to the gun is either a two-roll or a four-roll system.
A standard two-roll system is shown in Figure 3-17, and
a four-roll drive system is shown in Figure 3-18. The
rollers shown in Figure 3-19 are grooved for driving
specific sizes and types of wire. If the groove does not
match the wire type and size, the wire will seize in the
groove and not feed properly.
Chapter 3 Equipment Set-up and Control 33
Figure 3-14. Manufacturers place various controls on wire
feeders, depending on the use of the machine.
(Lincoln Electric Co.)
Gas post
flow
Gas
preflow
Gas
purge
Wire
jog
Wire
burnback
Wire
speed
Wire spool
brake
adjustment
Figure 3-15. Adjusting the brake increases or decreases
tension on the wire reel hub to prevent overspooling of wire.
Locking
pin
Brake adjustment