Definition
Squeeze time is the period of time programmed into the weld controller,
typically between the command to close the electrode and the beginning
of weld time (sometimes referred to as the programmed squeeze time).
The actual squeeze time is the amount of time that the electrode force
is applied before current begins to flow (see figure).
Description
Squeeze time allows the welding tip force to stabilize before the current
is applied. If the current is applied before the force is stabilized,
several phenomena are possible:
- Surface expulsion could occur, resulting in premature electrode
wear.
- The tip force may not be able to contain the expanding weld nugget,
resulting in interfacial expulsion.
- Current is turned on before the tips close causing arcing.
Detection
Significance
Quality, Workplace Issues, Cost, Downtime, Maintenance, Throughput (cycle
time; PPH), are all potentially affected by this condition.
Subordinate Causes
- Weld controller improperly programmed (longer squeeze time required)
- Wrong weld schedule
- Gun closing too slowly
- In some situations the gun closing valve and the weld current may
be controlled by independent controllers. Short squeeze time may be
caused by improper controller synchronization.
WeldHelp: To Issue/Cause
Matrix
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