The manufacturing of wire and cable is completely different from that of most mechanical and electrical products.
All wires and cables are made from conductor processing. The outer layer of the conductor is added with insulation, shielding, cable forming and sheath layer.
The more complex the product structure, the more layers are added.
The manufacturing technology of electric wires and cables is closely related to the development of special equipment and promotes each other.
New process requirements, promote the generation and development of new special equipment;
In turn, the development of new specialized equipment has promoted the promotion and application of new processes. Such as drawing, annealing, extrusion series line; The special equipment such as physical foaming production line promotes the development and improvement of the manufacturing technology of wires and cables, and improves the product quality and production efficiency of cables.
Basic process flow of plastic wire and cable manufacturing:
1. Single wire drawing of copper and aluminum
Wire and cable commonly use copper or aluminum rod, through one or several drawing die hole on wire drawing machine at room temperature, so that its section reduced, length increased, strength improved.
Wire drawing is the first working procedure of each wire and cable plant.
2. Wire annealing
When heated to a certain temperature, copper and aluminum wire can be recrystallized to improve their toughness and reduce their strength, so as to meet the requirements of wires and cables for conducting wire cores.
The key of annealing process is to eliminate the oxidation of copper wire.
3. The stranding of conductors
In order to improve the softness of electric wires and cables for laying and installation, the conductive core is made of multiple single wires twisted together.
From the form of stranded conductor, it can be divided into regular stranded and irregular stranded. Irregular hinge can be divided into bundle hinge, concentric compound hinge, special hinge and so on.
In order to reduce the occupied area of the wire and reduce the geometric size of the cable, the twisted conductor is used in the form of compaction at the same time, so that the common circle changes into a semicircle, a fan, a tile and a compaction circle.
This conductor is mainly used in power cables.
4. The insulation extrusion
Plastic wires and cables are mainly packed with solid insulation layer. The main technical requirements for plastic insulation extrusion are as follows:
4-1 Eccentricity: the deviation of the insulation thickness is an important indicator of the extrusion process. Most of the product structure size and its deviation are clearly specified in the standard.
4-2 Smoothness: the surface of the extruded insulating layer shall be smooth and free from surface roughness, burning and impurity
4-3 Density: the cross section of the extruded insulation layer shall be compact and solid, without pinholes visible to the naked eye, and the existence of air bubbles shall be eliminated.
For multi-core cables, in order to ensure the degree of molding and reduce the cable shape, it is generally necessary to twist them into a circle. The mechanism of stranding is similar to that of conductor stranding.
Cable technical requirements: one is to prevent the abnormal insulation core turned over and caused by the cable bending; the second is to prevent scratch insulation layer.
Most of the cables in cabling are with the completion of two other processes at the same time: one is filling, to ensure the cable after the roundness and stability; another is binding, to ensure that the cable core is not loose.
6. The protective layer
In order to protect the insulated core from being armored, it is necessary to protect the insulation layer properly. The inner sheath consists of squeezing the inner sheath (isolation sleeve) and wrapping the inner sheath (cushion layer).
The wrapping pad replaces the binding belt and is synchronized with the cabling process.
7. Armoring layer
For laying underground cable, it may bear a certain positive pressure in operation, and the inner steel belt armored structure is optional.
Cable laying in both positive pressure and tension role of the occasion (such as water, vertical shaft or large drop in the soil), should be selected with internal steel wire armor structure.
The outer sheath is the structural part that protects the insulation layer of electric wires and cables from environmental factors. The main function of the outer sheath is to improve the mechanical strength, anti-chemical corrosion, moisture-proof, waterproof, and prevent the cable from burning. According to the different requirements of the cable, the plastic sheath is directly extruded by the extruder.
Jiangsu Listrong Mechanical & Electrical Co., Ltd. integrates equipment research and development design, production and sales in one, specializing in the production of wire and cable machinery and equipment, mainly engaged in wire drawing machine, annealing machine, bunching machine, stranding machine, extruder, extruding machine, suitable for copper wire, copper alloy wire, stainless steel wire, aluminum wire... , has a strong technical, production, marketing, and service support team, with rich electrical machinery and equipment design, manufacturing and export experience.