Where conductor and crimp contact join in the conductor crimp area, a test must be performed. The intent is to verify accurate mechanical and electrical contact of the crimped termination. Goal of the test is to check whether the terminal crimp height is within the terminal supplier’s specifications. Therefore, a necessary and often mandatory test to ascertain the customer whether a correct match between wire/contact/tooling is made.
This check is only performed on the conductor crimp. The insulation crimp height varies largely with the chosen wire insulation, due to this fact the insulation crimp height is not measured.
Crimp Height Dimensions
Observe that each crimp terminal and conductor combination will have unique crimp height criteria. This is specified by the contact manufacturer for every wire diameter the contact will accommodate. Before starting the crimp height measurements, the correct crimp height with its tolerance window must be known. See an example below.
On the produced crimp contact, a 100% inspection must be performed. Unless agreed with the customer on a lower inspection frequency. Test data derived from the measurements must be made available to the customer per their request.
Relation with Pull Force test
For Class 3 products (high reliability) the crimp height measurement must be accompanied with a pull force test as well. For Class 1 and 2 products the pull force test is not mandatory by the IPC/WHMA-A-620 standard, as long as the crimp height measurement is performed.
Highly recommended to use a designated crimp height measurement device. A specialized measuring tool has a flat blade on one side where the crimped section is aligned with. The measuring is done with a pointed probe tip to assure accurate measurements
Contact the author: Ramon Koch