Definition
The interfacial welding force is more than that required by the applicable
specification.
Description
Weld force brings the metal between the electrodes together and provides
electrical continuity, the required welding pressure, and forging force,
so that a weld may be generated. The higher the force, the lower the
interfacial resistances, resulting in lower heat generation at the tip
to sheet and sheet to sheet interfaces.
On a microscopic scale, the surfaces of electrodes and workpieces consist
of peaks and valleys. When subjected to high force, the metal-to-metal
peaks will be largely flattened. The resulting contact area is more
than that produced by an appropriate force. Contact resistance will
therefore be lower, causing a lower amount of heat to be generated.
Measured weld force: That value of weld force set, for example,
using a force gage, before the workpiece is introduced.
Interfacial weld force: That force actually present at the sheet
to sheet interface. This is equal to the measured weld force minus the
force required to overcome poor fit up.
Detection
The condition may be indicated by:
Significance
Quality, Workplace Issues, Cost, Downtime, Maintenance, Throughput (cycle
time; PPH), are all potentially affected by this condition.
Subordinate Causes
- Faulty air pressure gage reading
- Improper weld force set
- Inadequate operator training
- Incorrect use of schedule table
WeldHelp: To Issue/Cause
Matrix
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