Tweco 250i Transmig Inverter - Manual (Page 62)

TRANSMIG 250I BASIC WELDING
BASIC WELDING 4-6 Manual 0-5187
Basic MIG (GMAW/FCAW) Welding Troubleshooting
FAULT CAUSE REMEDY
1 Undercut A Welding arc voltage too
high.
A Decrease voltage or increase the wire feed speed.
B Incorrect MIG Torch angle B Adjust angle.
C Excessive heat input
C Increase the MIG Torch travel speed and/or decrease
welding current by decreasing the voltage or
decreasing the wire feed speed.
2 Lack of penetration A Welding current too low A Increase welding current by increasing wire feed
speed and increasing voltage.
B Joint preparation too nar-
row or gap too tight
B Increase joint angle or gap.
C Shielding gas incorrect C Change to a gas which gives higher penetration.
3 Lack of fusion Voltage too low Increase voltage.
4 Excessive spatter A Voltage too high A Decrease voltage or increase the wirespeed control.
B Voltage too low B Increase the voltage or decrease wirespeed.
5 Irregular weld shape A Incorrect voltage and
current settings. Convex,
voltage too low. Concave,
voltage too high.
A Adjust voltage and current by adjusting the voltage
control and the wirespeed control.
B Wire is wandering. B Replace contact tip.
C Incorrect shielding gas C Check shielding gas.
D Insufficient or excessive
heat input
D Adjust the wirespeed control or the voltage control.
6 Weld cracking A Weld beads too small A Decrease travel speed
B Weld penetration narrow
and deep
B Reduce current and voltage and increase MIG Torch
travel speed or select a lower penetration shielding
gas.
C Excessive weld stresses C Increase weld metal strength or revise design
D Excessive voltage D Decrease voltage.
E Cooling rate too fast E Slow the cooling rate by preheating part to be welded
or cool slowly.
7 Cold weld puddle A Loose welding cable con-
nection.
A Check all welding cable connections.
B Low primary voltage B Contact supply authority.
C Fault in power source C Have an Accredited CIGWELD Service Provider test
then replace the faulty component.
8 Arc does not have
a crisp sound that
short arc exhibits
when the wirefeed
speed and voltage are
adjusted correctly.
The MIG Torch has been
connected to the wrong
voltage polarity on the
front panel.
Connect the MIG torch to the positive (+) welding
terminal for solid wires and gas shielded flux cored
wires. Refer to the electrode wire manufacturer for
the correct polarity.
Table 4-3: GMAW (MIG) Welding Problems