Welding Troubleshooting: Causes & Fixes

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Problems on this page:

Poor or inconsistent weld quality Excessive spatter or burn-through Wire feed problems / burnback Porosity in the weld Lack of fusion or penetration Arc start or striking problems

Poor or inconsistent weld quality

Hits OEE: Quality

Symptoms: Weak welds, porosity, inconsistent appearance, weld rejects.

Worn tips/electrodes or liner

Replace contact tips/electrodes; check the wire liner.

Wrong parameters

Set voltage/current/wire-feed/travel to the qualified procedure.

Dirty or oily base material

Clean the joint; remove oil, rust and scale.

Poor ground / shielding gas

Check the work clamp/ground and shielding-gas flow and coverage.

Prevention: Consumable schedule, parameter control, joint prep, gas/ground checks.

Excessive spatter or burn-through

Hits OEE: Quality

Symptoms: Heavy spatter, holes/burn-through, rework and clean-up.

Current or voltage too high

Lower to the qualified parameters for the thickness.

Travel speed too slow

Increase travel speed; check robot/operator technique.

Wrong gas or low flow

Verify gas type and flow; check for draughts disturbing coverage.

Prevention: Parameter control, gas checks, fixture/fit-up consistency.

Wire feed problems / burnback

Hits OEE: Availability

Symptoms: Erratic MIG wire feed, burnback to the contact tip, stoppages.

Worn or wrong liner/tip

Replace the liner and contact tip with the correct size.

Drive-roll tension or groove

Set drive-roll tension; use the correct groove for the wire.

Dirty or cast wire

Use clean wire; check spool and inlet guide.

Prevention: Consumable schedule, drive-roll setup, clean wire.

Porosity in the weld

Hits OEE: Quality

Symptoms: Gas pores or pinholes in the bead, failed inspection, weak joints.

Inadequate shielding gas

Check gas flow, coverage and leaks or draughts; set the correct flow.

Contaminated base metal or wire

Clean oil, rust, paint and moisture; store wire dry.

Wrong gas or technique

Use the correct gas mix; adjust travel angle and stick-out.

Prevention: Gas system checks, surface and wire cleanliness, draught control.

Lack of fusion or penetration

Hits OEE: Quality

Symptoms: Weld not fused to the base or root, undersized joint, rejects.

Heat input too low

Increase amperage and voltage and reduce travel speed to spec.

Poor joint prep or fit-up

Correct the bevel, root gap and cleanliness.

Wrong technique or angle

Adjust torch angle and aim; keep the arc on the joint root.

Prevention: WPS adherence, joint-prep standards, operator technique checks.

Arc start or striking problems

Hits OEE: Availability

Symptoms: Hard to strike an arc, stuttering start, sticking electrode.

Poor ground or work-clamp connection

Clean and secure the work clamp; check the return cable.

Wrong polarity or start settings

Set the correct polarity and start parameters for the process.

Worn contact tip or consumables

Replace the contact tip, liner and electrode.

Prevention: Ground integrity, correct settings, consumable replacement.

Welding troubleshooting FAQ

Welding: what causes poor or inconsistent weld quality, and how do I fix it?

Symptoms: Weak welds, porosity, inconsistent appearance, weld rejects. Likely causes: Worn tips/electrodes or liner; Wrong parameters; Dirty or oily base material; Poor ground / shielding gas. Fixes: Replace contact tips/electrodes; check the wire liner. Set voltage/current/wire-feed/travel to the qualified procedure. Clean the joint; remove oil, rust and scale. Check the work clamp/ground and shielding-gas flow and coverage. Prevention: Consumable schedule, parameter control, joint prep, gas/ground checks.

Welding: what causes excessive spatter or burn-through, and how do I fix it?

Symptoms: Heavy spatter, holes/burn-through, rework and clean-up. Likely causes: Current or voltage too high; Travel speed too slow; Wrong gas or low flow. Fixes: Lower to the qualified parameters for the thickness. Increase travel speed; check robot/operator technique. Verify gas type and flow; check for draughts disturbing coverage. Prevention: Parameter control, gas checks, fixture/fit-up consistency.

Welding: what causes wire feed problems / burnback, and how do I fix it?

Symptoms: Erratic MIG wire feed, burnback to the contact tip, stoppages. Likely causes: Worn or wrong liner/tip; Drive-roll tension or groove; Dirty or cast wire. Fixes: Replace the liner and contact tip with the correct size. Set drive-roll tension; use the correct groove for the wire. Use clean wire; check spool and inlet guide. Prevention: Consumable schedule, drive-roll setup, clean wire.

Welding: what causes porosity in the weld, and how do I fix it?

Symptoms: Gas pores or pinholes in the bead, failed inspection, weak joints. Likely causes: Inadequate shielding gas; Contaminated base metal or wire; Wrong gas or technique. Fixes: Check gas flow, coverage and leaks or draughts; set the correct flow. Clean oil, rust, paint and moisture; store wire dry. Use the correct gas mix; adjust travel angle and stick-out. Prevention: Gas system checks, surface and wire cleanliness, draught control.

Welding: what causes lack of fusion or penetration, and how do I fix it?

Symptoms: Weld not fused to the base or root, undersized joint, rejects. Likely causes: Heat input too low; Poor joint prep or fit-up; Wrong technique or angle. Fixes: Increase amperage and voltage and reduce travel speed to spec. Correct the bevel, root gap and cleanliness. Adjust torch angle and aim; keep the arc on the joint root. Prevention: WPS adherence, joint-prep standards, operator technique checks.

Welding: what causes arc start or striking problems, and how do I fix it?

Symptoms: Hard to strike an arc, stuttering start, sticking electrode. Likely causes: Poor ground or work-clamp connection; Wrong polarity or start settings; Worn contact tip or consumables. Fixes: Clean and secure the work clamp; check the return cable. Set the correct polarity and start parameters for the process. Replace the contact tip, liner and electrode. Prevention: Ground integrity, correct settings, consumable replacement.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Stop the same fault coming back

Recurring welding stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: EU-built, so your production data stays in EU jurisdiction, with computer-vision true-cause of micro-stops, a closed loop from PLC-read OEE to an auto-routed work order, and ISO 27001 / 20000-1 / 9001 (supports audit-readiness).

See how Fabrico finds root cause

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Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover