Common Mig Shielding Gases; Troubleshooting Guide For Semiautomatic Welding Equipment - Miller MILLERMATIC DVI Owner's Manual

8-16. Common MIG Shielding Gases

This is a general chart for common gases and where they are used. Many different combinations (mixtures) of
shielding gases have been developed over the years. The most commonly used shielding gases are listed in the
following table.
Gas
Argon
Argon + 25% CO
2
80% or greater Argon +
balance CO or Oxygen
2
100% CO
2
Tri-Mix 2
1 Limited short circuiting use
2 90% HE + 7-1/2% AR + 2-1/2% CO

8-17. Troubleshooting Guide For Semiautomatic Welding Equipment

Problem
Wire feed motor operates, but
wire does not feed wire does not feed.
Wire curling up in front of the
wire feed rolls (bird nesting). wire feed rolls (bird nesting)
Wire feeds, but no gas flows. Gas cylinder empty.
OM-1330 Page 40
Spray Arc Steel Short Circuiting Steel
X
2
Probable Cause
Too little pressure on wire feed rolls.
Incorrect wire feed rolls.
Wire spool brake pressure too high.
Restriction in the gun and/or assembly.
Too much pressure on wire feed rolls.
Incorrect cable liner or gun contact tip size.
Gun end not inserted into drive housing properly.
Dirty or damaged (kinked) liner.
Gas nozzle plugged.
Gas cylinder valve not open or flowmeter not adjusted.
Restriction in gas line.
Loose or broken wires to gas solenoid.
Gas solenoid valve not operating.
Incorrect primary voltage connected to welding power
source.
Application
Short Circuiting
Stainless Steel
X
1
X
X
X
Increase pressure setting on wire feed rolls.
Check size stamped on wire feed rolls, replace to match
wire size and type if necessary.
Decrease brake pressure on wire spool.
Check and replace cable, gun, and contact tip if
damaged. Check size of contact tip and cable liner,
replace if necessary.
Decrease pressure setting on wire feed rolls.
Check size of contact tip and check cable liner length
and diameter, replace if necessary.
Loosen gun securing bolt in drive housing and push gun
end into housing just enough so it does not touch wire
feed rolls.
Replace liner.
Replace empty gas cylinder.
Clean or replace gas nozzle.
Open gas valve at cylinder and adjust flow rate.
Check gas hose between flowmeter and wire feeder, and
gas hose in gun and cable assembly.
Have Factory Authorized Service Agent repair wiring.
Have Factory Authorized Service Agent replace gas
solenoid valve.
Check primary voltage and relink welding power source
for correct voltage.
Aluminum
X
Remedy