Squeeze Time Short

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

• Cracks and Holes
• Expulsion/Burn Through
• Poor Class A Appearance
• Arcing

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.