Mig Wire Feeding Issues

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.

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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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very common problem in wire welding.

Too loose and you have no wire feeding

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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

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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

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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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Documents

Mig Wire Feeding Issues