Firepower MST 140i, Operating Manual

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Firepower MST 140i
BASIC WELDING GUIDE 4-8 Manual 0-5338
Basic MIG 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 Welding current too low Increase welding current.
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 travel
speed settings. Convex, voltage
too low. Concave, voltage too
high.
A Adjust voltage and travel speed by adjusting the
voltage control and the wirespeed control.
B Wire is wandering. B Check to see if it is near the end of the roll
of wire and replace when necessary. If the
problem continues, tighten the nozzle to see
if this corrects the problem. Then 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.
E Incorrect gun manipulation or
angle
E Manipulate the gun correctly or place it in
correct angle.
6 Weld cracking A Weld high carbon steel without
pre/post heat treatment
A Have sufficient pre/post heat treatment before
welding high carbon steel.
B Incompatible filler metal used
to the base metal
B Use correct filler metal.
C Weld beads too small C Decrease travel speed.
D Weld penetration narrow and
deep
D Reduce current and voltage and increase MIG
Gun travel speed or select a lower penetration
shielding gas.
E Excessive weld stresses E Increase weld metal strength or revise design
F Excessive voltage F Decrease voltage.
G Cooling rate too fast G Slow the cooling rate by preheating part to be
welded or cool slowly.