Issue: Non-Round Welds

Welds or weld buttons are not circular.

Description

Non-round welds may be caused in several ways. Typically they are the result of using worn electrode tips, improperly aligned welding equipment, or insufficient weld energy. Reference should be made to appropriate company standards to determine whether any non-round conditions are acceptable.

Detection

A non-circular and/or unsmooth electrode impression on the workpiece before teardown may indicate the presence of a non-round weld. Note that non-round welds can also occur under indentations with a perfect appearance.

After teardown, non-round welds would be indicated by the shape of the remaining
button.

Significance 

Quality, Workplace Issues, Cost, Downtime, Maintenance, Throughput (cycle time; PPH) are all potentially affected by this condition. Special considerations are noted below:

Maintenance: Recurrent nonround welds may indicate that equipment maintenance is required.

Possible Causes

Strong Possibilities

• Dirty material
• Electrode faces not parallel to workpiece
• Electrode skidding/sliding
• Electrode wear
• Excessive sealer
• Inadequate electrode alignment
• Incorrect cylinder
• Incorrect electrode dressing
• Incorrect test procedure
• Poor electrical connections
• Poor or varying part fit-up
• Shunting of gun or parts
• Weld current low
• Weld time short
• Wrong tips

Weak Possibilities

• Damaged part
• Incorrect material/coating
• Incorrect workpiece selected
• Poor electrode follow-up
• Wrong cable/shunts
• Wrong shank
• Wrong transformer

Note: Also see Mislocated/Edge Welds.