A crimped terminal is one of the most important mechanical and electrical joints in a wire harness. When it fails, it usually fails intermittently: a connection that works at the bench and drops out under vibration. Defining how crimp quality is checked is part of a complete RFQ.
Crimp quality is not a single number. It is a combination of visual criteria, dimensional checks, and functional tests, and each one should be agreed with the factory before production rather than assumed.
Visual checks come first
A good crimp starts with the wire and terminal prepared correctly. Check that the strip length matches the terminal so the conductor reaches the crimp barrel without being caught by the insulation crimp, and that no strands are cut, nicked, or left outside the barrel.
Look at the insulation crimp as well as the conductor crimp. The insulation should be held firmly without crushing the wire or piercing the jacket. A crimp that looks clean but grips the wrong part of the terminal is a latent failure.
Crimp height and width
Crimp height is the most common measurable dimension for a terminal. It is normally checked against a value that comes from the terminal and wire manufacturer, or from a first-article sample that has been cut apart and verified. The same logic applies to crimp width where the tooling measures it.
The important point for an RFQ is that crimp height should be a controlled dimension with a value agreed in advance, not something decided on the day. If the customer has an approved terminal application specification, send it with the RFQ.
Pull-force and cross-section checks
Pull-force (tensile) testing checks how firmly the terminal grips the conductor. It is a destructive test, so it is normally done on samples or on a defined number of pieces per lot rather than on every part.
Cross-section analysis is the definitive visual check of a crimp: the terminal is cut, mounted, and ground so the material flow inside the barrel can be inspected. It verifies that the wire fills the barrel, the seams close correctly, and there is no significant deformation of the terminal or the conductor.
Both checks need a defined sample rate and acceptance criteria. If these tests are part of your requirement, state the method, the sample quantity, and what happens when a result falls outside the agreed range.
Continuity and electrical testing
Electrical continuity and short testing catch the faults visual checks miss, such as a strand touching an adjacent cavity or a missing contact. State whether the test is done on every assembly or on a sampling plan, and which circuits are covered.
For a custom wire harness, the inspection combination that fits your product — visual, dimensional, pull-force, cross-section, and continuity — should be written into the RFQ or the inspection plan. A clear quality clause lets the factory quote the actual inspection work instead of assuming a generic level, and it gives both sides the same definition of an acceptable termination.
The How to Prepare a Wire Harness RFQ guide covers the rest of the information that speeds up an OEM quotation.