Applicable Systems
Power MIG
Symptoms
The welding arc is unstable, producing excessive spatter. The weld bead is irregular and the welder displays an arc stability fault.
Possible Causes
- Welding cable connection loose at the torch or work clamp, causing voltage drop
- Wire feed speed inconsistent due to worn drive rolls or incorrect tension
- Shielding gas flow insufficient or excessive, disrupting the arc plasma
- Contact tip worn oversized, causing poor electrical transfer
Troubleshooting Steps
- Step 1: Check and clean all cable connections at the torch, feeder, and work clamp
Tighten to the specified torque; look for overheating discoloration - Step 2: Inspect the drive rolls for wear and verify the groove matches the wire size
Replace worn rolls and set the correct tension per the manual - Step 3: Verify the shielding gas flow rate (typically 15-25 CFM for MIG)
Check for gas leaks at all fittings using soap solution - Step 4: Measure the contact tip bore and compare to the wire diameter
Replace if bore is more than 0.5mm larger than the wire diameter
How to Reset
Reset: The fault clears after the root cause is corrected. Restart the welder and verify arc stability on a test coupon.
Common Replacement Parts
- Contact tip: M6 or M8, match wire size (Replace every 8-12 hours of welding)
- Drive roll: V-groove or knurled, match wire type (Replace when wire slip is detected)
- Shielding gas: 75/25 Ar/CO2 for mild steel (Verify gas type for the application)
Frequently Asked Questions
- Q: How often should I replace the contact tip?
Every 8-12 hours of welding or when arc instability is noticed. Use only OEM tips to ensure bore precision.
- Q: What gas flow rate should I use?
15-25 CFM for MIG, 15-20 CFM for TIG. Too high causes turbulence and air entrainment; too low gives poor coverage.
- Q: What causes wire feed problems?
Worn drive rolls, incorrect tension, kinked liner, or oversized contact tip. Inspect the entire feed path.
Source: OEM Operation Manual
Category: Welding