Tweco 211i Fabricator - Manual (Page 67)

BASIC WELDING FABRICATOR 211i
Manual 0-5157 4-7 BASIC WELDING
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 Gun angle B Adjust angle.
C Excessive heat input C Increase the MIG Gun 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 narrow
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 Velocity 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 Gun 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 Tweco 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 Gun has been con-
nected to the wrong voltage
polarity on the front panel.
Connect the MIG Polarity Cable to the positive (+) welding
terminal for solid wires and gas shielded flux cored wires.
Refer to the electrode wire manufacturer for the correct
polarity.
9 Poor weld result from
setup chart parameters
Contact tip has arc marks in
the bore causing excessive
drag on the wire.
Replace the contact tip with only a Genuine Tweco Velocity
contact tip.
Table 4-4: MIG (GMAW /FCAW) Welding Problems