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Overview of wire and cable manufacturing process
The manufacture of wire and cable is completely different from the production mode of most electromechanical products. Electromechanical products are usually assembled into a part of the other parts, a number of components and then assembled into a single product, the product to the number of units or pieces measured. Wire and cable is based on the length of the basic unit of measurement. All wire and cable from the conductor processing began, in the outer layer of the conductor with insulation, shielding, cable, protective layer, etc. and made into wire and cable products. The more complex the product structure, the more the stacking level.
First, wire and cable products manufacturing process characteristics:
1. Large-length continuous superposition combined production mode
The effect of large-length continuous superposition combined production mode on wire and cable production is global and controlled, which involves and affects:
(1) Production process and equipment layout
Production workshop of all kinds of equipment must be in accordance with the product requirements of the flow of reasonable discharge, so that all stages of semi-finished, in turn flow. Equipment configuration to consider the productivity of different production capacity of the balance, and some equipment may have to be configured two or more units, in order to make the production line to balance the production capacity. Therefore, the reasonable matching of equipment and the layout of production site must be balanced and considered according to the product and output.
(2) Production organization management
Production organization and management must be scientific and reasonable, careful and accurate, strict and meticulous, the operator must be meticulous in accordance with the requirements of the implementation of the process, any one link problems, will affect the smooth flow of products, affecting the quality and delivery. In particular, multi-core cable, a single line or basic unit length is short, or quality problems, the entire cable will be not enough length, resulting in scrap. Conversely, if a unit length is too long, it must be sawed off to cause waste.
(3) Quality Management
The production mode of the combination of large length and continuous superposition makes the quality of the whole cable be affected by a problem in any part of the process. The more the quality defects occur in the inner layer, and the failure to detect the termination of production in time, the greater the damage. Because the production of wire and cable is different from the assembled product, it can be disassembled and replaced by another, and the quality problem of any part or process of wire and cable is almost irreparable and make up for this cable. The treatment after the event is very negative, not sawing short is degraded processing, or scrap the entire cable. It can't disassemble the reload.
The quality management of wire and cable must be through the whole production process. Quality Management Inspection Department to the entire production process tour inspection, the operator self-test, up and down the process of mutual inspection, which is to ensure product quality, improve the economic efficiency of enterprises an important guarantee and means.
2. Many kinds of production technology, material flow
Wire and cable manufacturing involves a wide range of processes, from non-ferrous metal smelting and pressure processing, to plastics, rubber, paint and other chemical technology, fiber materials around the packaging, weaving and other textile technology, to metal materials around the wrapping and metal strip longitudinal package, welding metal forming process and so on.
The various materials used in the manufacture of wire and cable are not only categories, varieties, specifications, but also large quantities. Therefore, the dosage of various materials, standby volume, batch cycle and volume must be approved. At the same time, the decomposition of waste treatment, recycling, reuse and waste disposal, as an important part of management, do a good job of material management, pay attention to saving work.
Wire and cable production, from raw materials and all kinds of auxiliary materials in and out, storage, the transfer of semi-finished products to the product storage, factory, material flow, must be reasonable layout, dynamic management.
3. Multi-purpose equipment
Wire and cable manufacturing use of the industry's technical characteristics of the special production equipment to adapt to the structure of cable products, performance requirements, to meet the large length of continuous and as high as possible production requirements, thus forming a dedicated cable manufacturing equipment series. such as extrusion machine series, pull line machine series, stranding machine series, around the Charter series.
Wire and cable manufacturing process and special equipment development is closely related to each other to promote. New process requirements to promote the emergence and development of new special equipment, in turn, the development of new special equipment, and improve the promotion of new technology and application. such as wire drawing, annealing, extrusion series line, physical foaming production line and other special equipment, promote the wire and cable manufacturing process development and improvement, improve the cable product quality and production efficiency.
Second, the main technology of wire and cable
Wire and cable is through: pulling, twisting, covering three kinds of process to complete the production, the more complex model specifications, the higher the repeatability.
1. Drawing system
In metal pressure processing. Under the external force, the metal is forced through the die (Pressure wheel), the metal cross section area is compressed, and the required cross-sectional area shape and size of the technical processing method is called metal pull system.
Drawing process: monofilament pulling and twisting system.
In order to improve the softness of the wire and cable, the overall degree, so that more than 2 of the single line, according to the direction of the regulation interwoven together called twisted system.
Cutter Process: Conductor twisted, cable, woven, steel wire armored and winding.
According to different performance requirements of wire and cable, special equipment is used to cover different materials in the outer bread of conductor. Coating Process points:
A． Squeeze bag: rubber, plastics, lead, aluminum and other materials.
b． Longitudinal package: rubber, wrinkle aluminum tape material.
C． Wrap: Ribbon tape, mica tape, alkali-free glass fiber belt, non-woven fabric, plastic belt, etc., line-like cotton yarn, silk and other fiber materials.
D． Dip coating: Insulating paint, bitumen, etc.
Three, plastic wire and cable manufacturing basic process
1. Copper and Aluminum monofilament drawing
Wire and cable commonly used in copper, aluminum bar, at room temperature, the use of wire drawing machine through a or several stretch die hole, so that its section reduction, length increase, strength increased. Wire drawing is the first procedure of each wire and cable company, the main technological parameter of drawing is the technology of blending.
2. Single Wire annealing
The copper and aluminum monofilament can be heated to a certain temperature to improve the toughness of monofilament and reduce the strength of single filament in order to meet the requirements of wire and cable for conductive core. The key to annealing process is to prevent the oxidation of copper wire.
3. Twisted Conductors
In order to improve the softness of the wire and cable, in order to install, conductive wire core to take a number of monofilament twisted. From the twisted form of conductive wire core, it can be divided into rules and irregular twist. The irregular twisted-pair is divided into strands, concentric-twisted, special-twisted and so on.
In order to reduce the area of the conductor, reduce the geometrical size of the cable, in the twisted conductor of the same time the form of tight pressure, so that the ordinary circle variation of semicircle, fan, tile-shaped and tight pressure of the circle. This kind of conductor is mainly used in power cable.
4. Insulation extrusion
Plastic wire and cable mainly used extruded solid insulation layer, plastic insulation extrusion of the main technical requirements:
4. 1. Eccentricity: Extrusion insulation thickness deviation value is an important indicator of extrusion process level, most of the product structure size and its deviation value in the standard are clearly defined.
4. 2. Smoothness: Extruded insulating layer surface requirements smooth, no surface roughness, scorch, impurity quality problems
4. 3. Compactness: The cross section of the extruded insulating layer should be compact and solid, with no visible pinhole to prevent the presence of bubbles.
For multi-core cables, in order to ensure the forming degree and reduce the shape of cable, it is necessary to twist the cable into a circle. The mechanism of the stranding is similar to that of the conductor, because of the large diameter of the cutter, most of them adopt no back-twisting method. The technical requirements of cable forming: one is to eliminate the abnormal insulation core to turn over and lead to the twisting of the cable, the second is to prevent the insulation layer is scratched.
Most of the cables in the cable at the same time with the completion of two other processes: one is filled to ensure that the cable after the round and stable; one is lashing, to ensure that the cable core is not loose.
6. Inner protection layer
In order to protect the insulating core from being 疙, the insulating layer should be properly protected, the inner layer is divided: the Inner protective layer (isolation sleeve) and the wrapping layer (cushion layer) are wrapped. The wrapping cushion is substituted for the banding belt and the cable operation is synchronized.
Laying in the underground cable, the work may withstand a certain positive pressure, you can choose the steel tape armored structure. Cable laying in both positive pressure and tensile action of the occasion (such as water, vertical shaft or large drop in the soil), should be selected with a steel wire armored structure.
8. External jacket
The outer sheath is the structural part that protects the insulating layer of the wire and cable against the environmental factors. The main role of external sheath is to improve the mechanical strength of wire and cable, chemical corrosion prevention, moisture-proof, waterproof immersion, to prevent cable burning and other capabilities. According to the different requirements of the cable, the extrusion machine is used to squeeze the plastic sheath directly.