Processus de fabrication des faisceaux de câbles OEM: 8 Étapes depuis la coupe du fil jusqu'à 100% Essai
OEM wiring harness manufacturing is the build-to-print production of a custom wire harness: the customer supplies the drawing and connector schedule, and the factory converts standard wires, terminals and connectors into a finished, 100% electrically tested assembly. A professional OEM harness line runs eight controlled steps — from automated wire cutting to full electrical testing — under workmanship standards such as CIB/WHMA-A-620.
Below is how Yueqing Chengli Electronic Technology Co., Ltd. runs that process for automotive, appliance and new-energy harness programs, plus the quality checkpoints B2B buyers should expect at each step.
Étape 1 — Wire Cutting and Stripping
Automatic cut-and-strip machines cut each wire to drawing length (typical tolerance ±1–3 mm depending on length) and strip insulation without nicking strands. Machine-calibrated blade depth and pull-off tests on stripped ends prevent hidden strand damage that later becomes a field failure.
Étape 2 — Terminal Crimping
Terminals are crimped on semi-automatic presses or fully-automatic crimping machines. A controlled crimp is verified by crimp height (micrometer, per terminal spec) et pull-off force (sampled per run); modern presses add crimp-force monitoring (CFM) to catch every anomalous crimp in real time.
Étape 3 — Soldering and Ultrasonic Welding
Where drawings call for soldered splices or welded splices, solder pots or ultrasonic metal welding are used. Ultrasonic splicing produces a molecular bond without solder and is preferred for high-current battery and ground splices in EV harnesses.
Étape 4 — Assembly and Routing on Layout Boards
Wires are laid on a full-size assembly board (fixture) printed with the harness drawing. Operators route, insert terminals into connector housings (with TPA/CPA secondary locks checked), apply tape branches and sleeve positions exactly as drawn. The board is the first quality gate: a misplaced branch is caught before taping.
Étape 5 — Protective Finishing
Harnesses receive their protection layers: PVC/electrical tape wraps, corrugated conduit (loom), gaine tressée, heat-shrink tubing at splices, and grommets where wires pass through panels. Material selection follows the environment — temperature class, abrasion, and fluid exposure.
Étape 6 — 100% Tests électriques
Every finished harness is tested on a continuity/hipot test board built to the drawing: continuité point à point, short-circuit between all circuits, et (for programs requiring it) tenue diélectrique. A harness that has not passed 100% testing must never ship — ask any prospective supplier how they guarantee this.
Étape 7 — Visual and Dimensional Inspection
Workmanship is judged against CIB/WHMA-A-620 (the industry standard for cable and wire harness assemblies): crimp insulation support, conductor damage limits, tape overlap, sleeve shrink, connector latch condition, and label placement. Dimensional checks confirm overall length, branch lengths and connector orientations.
Étape 8 — Packing and Traceability
Harnesses are coiled or packed to prevent deformation, labeled with part number and revision, and packed with lot traceability linking wires, terminal lots and test results — so any field issue can be traced to its material lot.
Quality Checkpoints Buyers Should Expect
| Checkpoint | Méthode | Reference |
|---|---|---|
| Crimp quality | Crimp height + pull-off force + CFM monitoring | CIB/WHMA-A-620, terminal spec |
| Splice integrity | Ultrasonic weld / solder inspection, essai de traction | CIB/WHMA-A-620 |
| Electrical function | 100% continuité + short + hipot on test board | Customer drawing |
| Workmanship | Visual inspection vs A-620 acceptance classes | Classe IPC/WHMA-A-620 1/2/3 |
| Traçabilité | Lot labels linking wire/terminal/test data | Factory QMS |
What to Ask an OEM Harness Supplier Before Placing an Order
- How is 100% electrical testing guaranteed — dedicated test boards per drawing, or universal testers?
- Which workmanship standard governs acceptance (IPC/WHMA-A-620 class)?
- What crimp process controls exist (crimp height, pull test frequency, CFM)?
- How are engineering changes (revision updates) controlled on the board and in test?
- What is the MOQ and sample/PPAP-style approval flow? (See our liste de contrôle d'audit du fabricant.)
Chengli builds custom OEM harnesses for auto manufacturing and equipment factories (B2B only, MOQ à partir de 100 PCS). Compare our car wiring harness capabilities, learn the basics of wiring harnesses, ou send your drawing for a 24-hour quote.
