Inspecting crimp on connector terminals

The following are important things to look for in a good crimp are: undamaged terminal, terminal is not bent, Insulation in terminal window but not in wire crimp, insulation crimp not piercing wire, Insulation crimp properly wrapped, wire brush visible past wire crimp, brush not in connection area, bell mouth present, and micrometer across insulation crimp is in the tolerance window.
It is necessary to check that the connectors are properly crimped. Hand crimps, and machine crimps both need to have each crimp to be inspected. An improper crimp will greatly reduce the life of the connector terminal.
The wire crimp thickness should also be measured because each type connector head and wire gauge have a different tolerance of thickness. An incorrect thickness will not only reduce the life of the connector but may also fall apart immediately. Improper wire thickness may not always be visible to the naked eye or with a magnifying glass.

Proper place to measure wire crimp thickness. Blade part of micrometer on front of wire crimp. Pointer on the back part of wire crimp.

Important parts to a connector head

Wire crimp: section of the crimp that holds the striped wire.

Insulation crimp: section of the crimp that is over the entire wire.

Terminal: mating part of the connector.

Bell mouth: bulge at the end of the connection terminal.

Wire insulation: Outside covering part protecting the wire.

Wire brush: metal strands in the wire insulation.

Example of a good crimp.

Bad crimp examples.
Insulation in wire crimp (pinched insulation)

Brush inside connector terminal.

No brush past wire crimp

Official company crimp guidelines.
Molex- “Good Crimps and How to Recognize Them”

TE Connectivity “Crimp quality Guidelines”

Bob Willis “Crimp Connector Inspection & Quality Control”

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