MAINTENANCE AND TROUBLESHOOTING
4.4 MMA welding trouble shooting
The following chart addresses some of the common problems of MMA welding. In all cases of
equipment malfunction, the manufacturer’s recommendations should be strictly adhered to and
followed.
NO.
Problem
Possible Reason
Suggested Remedy
1
No arc
Incomplete welding circuit
Check earth lead is connected.
Check all cable connections.
Wrong mode selected
Check the MMA selector switch is
selected
No power supply
Check that the machine is switched
on and has a power supply
2
Porosit
y − s
mall
cavities or holes
resulting from gas
pockets in weld
metal
Arc length too long
Shorten the arc length
Work piece dirty,
contaminated or moisture
Remove moisture and materials like
paint, grease, oil, and dirt, including
mill scale from base metal
Damp electrodes
Use only dry electrodes
3
Excessive Spatter
Amperage too high
Decrease the amperage or choose a
larger electrode
Arc length too long
Shorten the arc length
4
Weld sits on top,
lack of fusion
Insufficient heat input
Increase the amperage or choose a
larger electrode
Work piece dirty,
contaminated or moisture
Remove moisture and materials like
paint, grease, oil, and dirt, including
mill scale from base metal
Poor welding technique
Use the correct welding technique or
seek assistance for the correct
technique
5
Lack of penetration
Insufficient heat input
Increase the amperage or choose a
larger electrode
Poor welding technique
Use the correct welding technique or
seek assistance for the correct
technique
Poor joint preparation
Check the joint design and fit up,
make sure the material is not too
thick. Seek assistance for the correct
joint design and fit up
6
Excessive
penetration -
burn through
Excessive heat input
Reduce the amperage or use a
smaller electrode
Incorrect travel speed
Try increasing the weld travel speed
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