Automobile wires are low-voltage wires, and they need to have good flexibility during assembly (the assembly space is small), so the conductors are all twisted by multiple strands of copper monofilaments, the number of which ranges from a few to hundreds of monofilaments. The diameter varies from 0.16mm to 0.4mm. Most of the automobile wires are thin-walled wires, and the insulation thickness is mostly within 0.5mm. The conductor is slightly skipped and not round, which will directly cause the surface to wrap up during the extrusion insulation process, and pits appear. Most of its quality problems are caused by conductor wire, back strands, crimping, and oxidation.