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8/11/2019 Mig Wire Feeding Issues
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Wire feeding issues
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MIG (GMAW) and flux-cored (FCAW) welding,
commonly referred to as wire welding,
The wire feed system uses a more complicated
mechanical system than the others to deliver the
welding wire to the weld pool and the current to
the wire, resulting in more potential problems in
the functioning of the welding equipment.
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Wire welding
Explored view of swan neck
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Wire delivery
System by ensuring the wireis not obstructed anywhere
along its path from the spool
tension to the contact tip &
every where in-between.
AWTI 3
Felt for wire cleaning
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Points to be checked for good wire
feeding in wire feeder and torch
Hub Tension
Check Drive Roll Pressure
Check Drive Roll Alignment
Check Inlet Guides
Check Liner Condition & Contact Tip Condition
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Hub Tension
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Hub tension
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Hub Tension
Not to over-tighten the hub tension, which allowsthe spool of wire to turn.
The hub tension is simply a means to keep the wire
from de-coiling off of the spool when wire feeding
stops.
This should be just tight enough to keep the wire
from de-coiling when you stop feeding a full spool at
maximum wire feed speed.
Over-tightening this will force the drive motor to
work harder just to get the wire off of the spool and
will lead to welding problems.
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Check Drive Roll Pressure
very common problem in wire welding.
Too loose and you have no wire feeding
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Check Drive Roll Pressure
Too tight crush the wire and flake off the coating,
deform the wire,
wear out the rollers,
damage the motor.
Wear out the grooved surfaces of the rolls resulting in poorfriction to feed the wire properly.
Deformed wire will wear grooves into the contact tip limitingelectrical conductivity and also causing poor feed ability.
Flaked coating will cause small flakes to enter the liner,
All wire feeding problem starts
AWTI 9
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Remedies
Drive roll tension should be adjusted so that it isnot too tight, but not too loose.
Startwith the drive roll pressure very loose.
Increase the pressure only until it is very difficult tostop the wire from feeding out of the contact tip.
Use a pliers or block of wood to try and stop thewire from feeding.
Go perhaps one-half of a turn beyond this point.
When the wire is actually stopped, the drive rollsshould spin on the wire and no bird nesting shouldoccur.
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Check Drive Roll Alignment
The drive rolls can be adjusted side-to-side to ensure theyare in line with the inlet guide to the GMAW gun.
Inlet guide
AWTI 11
Roller alignment
Inlet guide
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Case studies about improper roller
setting
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Misaligned Roller condition after usage
for 4 days
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CLOSE VIEW OF UNCLEANED ROLLERS
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Wire misalignment between rollers.
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Wire mis
Alignment
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Check Inlet Guides
The inlet guides should be of the proper size for the
wire used.
They should not have grooves in themoften caused
by misalignment or improper size.
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Inlet guide
Wire is peeling offBy misalignment
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Aligned Roller condition after usage for
4 days
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Check Liner Condition
The gun liner should be the proper size for the wire
being used and should also be clean and free of dust
and debris.
Over-tensioned wire will flake off and place excessiveparticles into the liner, clogging it up.
Using special wire lubricants can also cause the wire
to become wet and dust can collect on the wire
dragging it into the liner as well.
Liners are wear items and should be replaced on a
regular schedule.
19Wire liner
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Contact Tip Condition
Many times feeding problems can be fixed
by replacing the contact tip.
The contact tip can get clogged up from
spatter or from touching it to the weld
puddle.
If the wire is wearing grooves into the
contact tip you need to check your drive
roll tension.
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Contact tip
Clogged by spatters
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wearing groove into the contact tip
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Wire burn backs " during the weld
causes
Wire feeding too slowOperator keeping torch very close to weld puddle.
During a weld when MIG wire is restricted in theliner, (or) the tip (or) from lack of sufficient wiretension from the drive rolls.
The gun cable is twisted are a frequent for wirerestriction.
Melt the end of the contact tip. These problems can occur at the arc start or
during the a weld.
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Burn back control
The burn back feature is to produce a
preferred wire projection length from the
contact tip for weld initiation.
When terminating a weld you let go of the
trigger and hold the gun motionless.
The arc will continue for the duration you
have set, resulting in a precise wire projection.
This is an advanced feature
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AWTI 24