In the first part of this blog, we presented the connection technology "crimping". Now let's go into detail: After all, anyone who orders the corresponding parts and tools from Würth Elektronik should of course achieve optimal results. 

The crimping process:

1. The die is open. A contact is positioned on the anvil. The wire is inserted by hand or by machine.
2. The falling crimper pushes the wire into the crimp sleeve and captures the crimp edge.
3. In the further process, the crimp flanks are rolled in, the stranded conductor is compacted evenly and the crimp is formed.
4. The end position at a specified crimp height guarantees the necessary compression of the stranded conductors to form an almost gas-tight crimp.

If you have done everything right and inserted the vein correctly, you should come to the following conclusion:

What problems can arise during crimping?

If you do not apply a sufficiently high force during crimping or use the wrong crimping tool, cores will be pressed insufficiently or incorrectly. As a result of the faulty contacting, the contact resistance between the wire and the crimp contact increases. Furthermore, there is a risk that an incompletely pressed wire can be pulled out of the crimp sleeve.

On the other hand, a crimp connection must not be pressed too hard. Too much pressure or a tool that is too small can impermissibly reduce the cross-sections of fine-stranded stranded conductors. Furthermore, if the pressing force on fine-stranded stranded conductors is exceeded extremely, there is a risk that individual conductors will be sheared off. The reduced cross-section would reduce the current-carrying capacity of the connection. In addition, the sleeve of the crimp connector may become unusable due to cracking or breaking.

Errors can also occur during the stripping process. If no suitable tools are used for stripping, the quality depends significantly on the skill and experience of the user.

Typical mistakes to avoid:

• The crimp sleeve does not completely enclose the core insulation
• Remaining core insulation has been damaged by the stripping tool
• Individual wires have been damaged or cut off by the stripping tool
• Individual wires were subsequently twisted too much
• Single wires are no longer twisted
• Contact twisted
• Crimpla ash bent
• Contact bent
• Incorrect tool adjustment
• Incorrect selection of contact/conductor cross-section
• Incorrect crimp height

Quality control tests

Quality assessment and defect pattern: A pull-out tester is used to test the crimp connection. The strands should tear off unevenly (1), otherwise the contact was over-crimped (2) (leads to a predetermined breaking point) or not crimped strongly enough. (3).

As a non-destructive test, a crimp height measurement can be performed. The crimp height and width are specified by the manufacturer of the crimping tool in consultation with the contact manufacturer. This is the test method with the highest accuracy.

Finally, all that remains for us to say is: good luck with the crimping!