The process flow of manufacturing wires and cables is as follows:
1. Wire drawing "copper and aluminum monofilament"
Commonly used copper and aluminum rods for wires and cables, at room temperature, use a wire drawing machine to pass through one or several stretch die holes to reduce the cross-section, increase the length and increase the strength. Wire drawing is the first process of various wire and cable companies, and the main process parameter of wire drawing is die matching technology.
2. Cable technology---monofilament annealing
Copper and aluminum monofilaments are heated to a certain temperature to recrystallize the toughness of the monofilament and reduce the strength of the monofilament. Jinhuanyu wire and cable editor reminds to meet the requirements of wire and cable for conductive core. The key to the annealing process is to prevent the oxidation of the copper wire.
3. Stranding of conductors of wires and cables
In order to improve the flexibility of the wire and cable and facilitate the laying and installation, the conductive core is made of multiple monofilaments twisted. From the stranding form of the conductive core, it can be divided into regular stranding and irregular stranding. Irregular stranding is divided into bundle stranding, concentric twisting, special stranding and so on.
In order to reduce the occupied area of the wire and reduce the geometric size of the cable, the compacted form is adopted while twisting the conductor, so that the ordinary circle is transformed into a semicircle, sector shape, tile shape and compacted circle. This type of conductor is mainly used in power cables.
4. Insulation extrusion
Plastic wires and cables mainly use extruded solid insulation layers. The main technical requirements for plastic insulation extrusion:
(1) Eccentricity: The deviation value of the extruded insulation thickness is an important indicator of the level of the extrusion process. Most of the product structure dimensions and deviation values are clearly specified in the standard.
(2) Smoothness: The surface of the extruded insulation layer must be smooth, and there must be no poor quality problems such as surface roughness, burnt, and impurities.
(3) Density: The cross-section of the extruded insulation layer should be dense and strong, and no pinholes visible to the naked eye are allowed to prevent the existence of bubbles.
5. Wire and cable made into cable
For multi-core cables, in order to ensure the molding degree and reduce the appearance of the wire and cable, it is generally necessary to twist them into a circle. The mechanism of stranding is similar to that of conductor stranding. Because the stranding pitch diameter is large, most of them use no back-twisting method.
2 Technical requirements of Dacheng Cable:
One is to prevent the twisting of the cable caused by the overturning of the special-shaped insulated core;
The second is to prevent the insulating layer from being scratched.
Most of the cables are completed with the completion of the other two processes at the same time: one is filling to ensure the roundness and stability of the cable after the cable is formed; the other is binding to ensure that the cable core is not loose.
6. Inner sheath
The editor of Shenzhen Jinhuanyu Wire and Cable reminds everyone that in order to protect the insulated core from being damaged by the armor, the insulating layer needs to be properly protected. The inner protective layer is divided into: extruded inner protective layer (isolation sleeve) and wrapped inner Protective layer (cushion layer). The wrapping cushion layer replaces the binding tape and the cable forming process is performed simultaneously.
7. Armored cable
For cables laid underground, they may be subjected to certain positive pressure during work, and an inner steel tape armored structure can be selected. For cable laying in occasions with both positive pressure and tension (such as in water, vertical shafts or soil with large drops), a structural type with inner steel wire armor should be selected.
8. Outer sheath
The outer sheath is the structural part that protects the insulating layer of the wire and cable from environmental factors. The main function of the outer sheath is to improve the mechanical strength of the wire and cable, prevent chemical corrosion, moisture, waterproof, and prevent the cable from burning. Jinhuanyu wire and cable editor reminds that the plastic sheath can be directly extruded by the extruder according to the different requirements of the cable and wire.
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