Weld Seam Failure During Feeding – Causes, Inspection, Repair & Prevention Guide for Roll Forming Machines

Weld Seam Failure During Feeding

Roll Forming Machine Troubleshooting & Repair Guide

Weld seam failure during feeding occurs when the welded joint between two steel coils breaks or separates as it passes through the roll forming production line. In continuous production systems, steel coils are often joined using butt welding or lap welding so the machine can continue running without stopping for coil changes.

When the weld seam fails during feeding, the strip may suddenly separate, causing production interruptions and potential damage to equipment.

If this issue is not corrected, it may lead to several production problems including:

• Sudden strip breakage in the line
• Machine shutdowns and downtime
• Damage to entry guides or rollers
• Strip tension spikes
• Product defects around the weld area
• Increased scrap material

For manufacturers producing metal roofing panels, cladding sheets, structural decking, purlins, trims, and other roll formed components, maintaining strong and properly prepared weld seams between coils is critical for continuous production.

This guide explains the causes of weld seam failure during feeding, inspection procedures, corrective actions, and preventative maintenance strategies used by experienced roll forming technicians.

Causes of Wear or Failure

Weld seam failure typically occurs when the welded joint cannot withstand the forces applied during feeding and forming.

Poor Weld Quality

Weak or incomplete welds may fail when the strip is pulled through the machine.

Improper welding technique is a common cause.

Excessive Strip Tension

High strip tension during feeding may place excessive stress on the weld seam.

This can cause the weld to tear.

Weld Misalignment

If the welded joint is not properly aligned, the seam may catch on entry guides or rollers.

Thick Weld Bead

Excess weld material may interfere with machine components and cause the weld to break.

Material Thickness Differences

If two coils with different thicknesses are welded together, the joint may be structurally weak.

Weld Seam Impact with Rollers

If the weld seam passes through tight machine clearances, the impact may damage the weld.

Why It Happened and What Caused It

From a mechanical standpoint, the welded seam must pass through the roll forming machine while resisting several forces including:

• Strip tension
• Bending through rollers
• Contact with entry guides
• Feeding pressure from pinch rolls

If the weld seam does not have sufficient structural strength or proper geometry:

• Stress concentrates at the weld joint.
• The weld may crack or separate.
• The strip may break completely.

This failure may occur suddenly and cause the strip to whip or retract, potentially damaging equipment.

How to Inspect the Problem

Inspection Procedure

Proper inspection helps determine the cause of weld seam failure.

Step 1 – Inspect the Broken Weld

Examine the failed weld seam.

Look for:

• Incomplete weld penetration
• Cracks in the weld area
• Poor weld fusion

Step 2 – Inspect Weld Geometry

Check whether the weld bead is excessively thick or uneven.

Large weld beads may interfere with machine components.

Step 3 – Inspect Entry Guides and Rollers

Verify that the weld seam is not catching on guides or rollers.

Clearances may need adjustment.

Step 4 – Inspect Strip Tension

Check strip tension levels during feeding.

Excessive tension may stress the weld joint.

Step 5 – Inspect Material Compatibility

Ensure the welded coils have similar thickness and material properties.

Step-by-Step Technician Guide – How to Fix

Several corrective actions can prevent weld seam failure during feeding.

Method 1 – Improve Welding Technique

Use proper welding procedures to ensure full penetration and strong weld joints.

Method 2 – Grind Excess Weld Material

Remove excess weld bead to ensure smooth passage through machine components.

Method 3 – Reduce Strip Tension

Adjust tension settings to reduce stress on the weld seam.

Method 4 – Align the Welded Joint

Ensure both strips are aligned correctly before welding.

Method 5 – Inspect Machine Clearances

Verify that entry guides, pinch rolls, and rollers allow the weld seam to pass without interference.

Preventative Maintenance Tips

Routine inspection and proper welding procedures help prevent seam failures.

Train Operators on Proper Coil Welding

Operators should follow approved welding procedures for joining coils.

Inspect Weld Quality Before Feeding

Check weld seams for strength and geometry before feeding into the machine.

Maintain Proper Strip Tension

Avoid excessive tension that may stress the weld seam.

Smooth Weld Surfaces

Grinding the weld bead ensures smooth passage through the machine.

Monitor Weld Passage Through Machine

Operators should watch the weld seam as it enters the machine.

FAQ Section

What causes weld seam failure in roll forming lines?

Common causes include poor weld quality, excessive strip tension, weld misalignment, and interference with machine components.

Why are coils welded together in roll forming lines?

Coils are welded together to allow continuous production without stopping the machine.

Can weld seams damage roll forming machines?

Yes. Broken weld seams may cause strip whipping and equipment damage.

How can weld seam failure be prevented?

Proper welding techniques, tension control, and smooth weld geometry help prevent failures.

Should weld seams be ground smooth?

Yes. Grinding helps prevent interference with machine components.

Can different material thicknesses be welded together?

It is possible, but it may weaken the weld joint if not done properly.

Machine Matcher Technical Support

If your roll forming line is experiencing weld seam failures, strip breakage, or feeding instability, Machine Matcher technical specialists can help diagnose and resolve the issue.

Support services include:

• Roll forming machine troubleshooting
• Strip welding diagnostics
• Entry and feeding system inspection
• Production line performance evaluation
• Remote technical assistance

Submit your issue through the Machine Matcher Technical Support Desk:

Include the following information:

• Machine type
• Coil width, thickness, and material type
• Photos or videos showing the weld seam failure
• Production speed and strip tension settings

Our technicians will review the information and provide step-by-step recommendations to restore stable production.