Cause: Excessive Sealer

Definition
Too much sealer or adhesive is applied, or it is applied in the wrong location, such that weld quality is affected.

Description

• Although some sealers and adhesives are formulated for resistance spot welding, excessive quantities may increase welding interface resistance, impeding current flow.
• Weld schedules are typically developed, as required, to weld through sealers and adhesives. A weld made through mislocated sealer may not have the appropriate schedule, potentially affecting weld quality.
• Excessive sealer may contaminate the welding equipment, for example tip faces, causing inconsistent weld quality.

Detection
The condition may be indicated by:

• Cracks & holes
• Excessive indentation
• Expulsion/burn through
• Inconsistent weld quality
• Missing weld
• Nonround weld
• Sticking/stuck tips
• Stuck weld
• Undersized weld
• Contamination of workpieces and equipment

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

Workplace Issues: Excessive sealer/adhesives may contaminate the workplace environment

Subordinate Causes

• Malfunctions of sealer/adhesive applicator equipment
• Insufficient training of sealor application operators

Notes
Sealer /adhesive dispense rate may be affected by temperature. Ensure that material temperature is within the specified range.