Erratic wire feeding is one of the most common GMAW troubleshooting problems and can cause arc instability, excessive spatter, poor bead appearance, and inconsistent weld quality. This article explains six common causes, including contaminated liners, incorrect contact tips, inconsistent wire diameter, improper drive-roll tension, excessive spool tension, and MIG gun length or routing. It also explains why increasing drive-roll pressure often masks the actual problem instead of correcting it. A systematic troubleshooting approach that follows the wire from the spool to the contact tip can help identify the true source of feeding resistance. Most importantly, changing one variable at a time makes it possible to correct the root cause instead of temporarily hiding the symptom.
