Is It Necessary To Remove The Wire After Crimping With A Cold-pressing Pin? Correct Operation And Reason Analysis.
crimp contact After crimping, if it is necessary to replace or adjust the wire, a special pin puller or crimping tool must be used to pull the wire out in reverse. Direct pulling of the cable is strictly prohibited. Direct pulling will damage the locking structure of crimp contact pin, leading to unreliable connection or even complete device malfunction.
Why should the wire be carefully pulled out after cold crimping?
contact socket crimp A permanent connection is formed with the wire through mechanical compression and deformation. Once the internal elastic locking or indentation structure is formed, forcibly pulling will disrupt the metal stress distribution. Engineers should understand that crimping is essentially a cold welding process; the wire and pin body have already formed an airtight contact. Incorrect removal will cause crimp contact female inner diameter to expand, contact resistance to increase, and terminal burnout in vibration or temperature change environments.
Standard Procedure for Removing Cold Crimped Pin Wires
-
Identify the Terminal Model: Confirm the connector series to which the cold crimped pin belongs (e.g., Molex, JST, or TE). Pin pullers are not interchangeable between different series.
-
Use a dedicated pin puller: Insert the pin puller into the locking position at the front of the terminal cavity. A "click" sound indicates that the elastic tab has been released.
-
Gently pull the wire: Keep the pin puller pressed against the locking position while slowly pulling the wire out along the axis. Do not force it if there is abnormal resistance.
-
Inspect the cold-pressed pin: After pulling it out, observe the crimped area for cracks or deformation. If damaged, discard it immediately and do not re-crimp it.
-
Re-crimp the new pin: Use the original specification cold-pressed pin and matching crimping pliers, and operate according to the stripping length and crimping height specifications.
Typical application scenarios and precautions
Scenario 1: Prototype debugging stage
Engineers frequently change test harnesses. It is recommended to reserve 10cm of redundant wire to avoid repeatedly pulling out the same cold-pressed pin. The purchasing department can choose "pre-crimped wire-connected terminals" as quick replacement parts.
Scenario 2: Production line rework station
If technicians find that the wire is mistakenly inserted into the hole, be sure to disconnect the power and release the connector's secondary lock. Statistics show that cold-pressed pins that have been inserted and removed more than three times experience a decrease in holding force of over 40% and should be replaced.
Scenario 3: High-Reliability Equipment (Automotive, Industrial Control)
Following the IPC/WHMA-A-620 standard, any removal operation after crimping is considered destructive. Project procurement must incorporate "maintainability design" into terminal selection—prioritizing split-type crimp terminals or tool-less pin removal structures.
Tip: After each removal operation, use a milliohm meter to measure the resistance of the cold-pressed pin's crimp point. A deviation exceeding 5% from the initial value indicates a failure.
