Nonround Weld
Definition
Welds or weld buttons are not circular.
Description
Nonround 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 nonround conditions are acceptable.
The following definitions are based on the Auto Body Consortium's Auto/Steel Partnership classifications of various button conditions:
Detection
A noncircular and/or unsmooth electrode impression on the workpiece before teardown may indicate the presence of a nonround weld. Note that nonround welds can also occur under indentations with a perfect appearance.
After teardown, nonround 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 Face 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 Guns 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 Cables/Shunts
- Wrong Shank
- Wrong Transformer
Note: Also see Mislocated/Edge Welds.