Automotive Wiring Harness assembly process (key points version)
The core of Automotive Wiring Harness assembly is "qualified materials, in place assembly, standardized wrapping, reliable fixing, and closed-loop inspection."The following is a summary of key control points based on common steps at the production site to facilitate training and self-inspection.
1. Assembling commonly used raw materials
Wire: Pay attention to wire diameter/color/printing/flame retardant level. Incoming materials need to be randomly inspected for appearance, continuity, and insulation.
Terminals and housings (connectors/locking parts): Pay attention to plating, insertion and extraction force, locking structural integrity and mating tolerances.
Tapes: Commonly used include PVC, cloth base, flannel, conductive tape, sponge double-sided tape, etc.; focus on controlling thickness, adhesion, elongation and temperature resistance.
Casing/bellows: used for wear resistance and protection; pay attention to wall thickness, inner diameter matching and temperature resistance and flame retardant requirements.
Cable ties/buckles/positioning parts: used for fixing and routing; pay attention to material strength, weather resistance and whether there is interference with the installation position.
2. Identification of incoming materials and process defects
Defective wires: inconsistent specifications, eccentricity, broken skin, oil scratches, unclear printing, abnormal insulation thickness, failed performance tests, etc.
Defective terminals: lack of plating/oxidation, deformation, burrs, dimensional deviation, abnormal insertion and extraction force, poor contact resistance, etc.
Defective plastic parts: lack of glue, blocked holes, flash cracks, deformation, water splash, insufficient holding power, substandard pressure and flame retardancy, etc.
Bad hardware: blistering and peeling of the coating, inconsistent dimensions and materials, serious burrs, failed performance tests, etc.
3. Assembly operation process (from board to parts)
1) Positioning of the upper board: Position the wires and branches on the assembly board according to the process diagram, starting with the trunk and then the branches to ensure that the wiring is straight and the bifurcation angles are consistent.
2) Plug-in assembly: When inserting terminals, it is recommended to hold the wire about 10-20mm below the terminal and insert it vertically and smoothly; after insertion, confirm that the terminal is locked in place and the secondary lock is in place.
3) Bending is prohibited: After the terminal is crimped, it is prohibited to bend it up and down at the root of the terminal, which may easily lead to poor fitting or subsequent fatigue fracture.
4. Bandaging and fixation (determines appearance and reliability)
Close winding: Reinforce 2 turns at the beginning and end, keep the overlap amount in the middle (commonly 1/2 to 1/3 tape width), no exposed wires, and the ends should be compacted without warping.
Dotting: used for local positioning and anti-scattering, overlapping 2-4 turns, no fly-away at the end.
Fixed corrugated pipe/PVC pipe: Reinforce with 1 turn at the beginning and 2 turns at the end, and wrap it evenly to ensure that the protective parts do not loosen.
Fork wrapping/branch: Position the roots of the forks first, and then wrap them to the branches respectively; the intersections must not be exposed, loose or fall off.
Interwinding: Used for areas that require flexibility or heat dissipation, with even spacing to avoid being too dense/thin, resulting in poor appearance or insufficient wear resistance.
5. Install corrugated pipes and ties
Pipe installation: The length and position of the corrugated pipe should be according to the process requirements. If necessary, use tools such as pipe loading tools to assist to avoid damaging the wire by pulling or pushing it hard.
Cable tie: The position should be away from moving parts and heat sources, and the tail should be trimmed flush without cutting hands; after fixing, check the tension and non-interference.
6. Final inspection and random inspection suggestions
Appearance: The wrapping is smooth, with no exposed lines/warping/wrinkling, and the branch roots are firm; the wiring and fixing points conform to the workmanship.
Electrical inspection: continuity, short circuit, insulation, and voltage resistance are carried out as required; key terminals are randomly inspected for pull-out force.
Dimensions: Trunk/branch lengths and bifurcation point positions are controlled according to drawings/processes, and any deviations will be reworked in a timely manner.
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