Basic knowledge of wire and cable


Overview of wire and cable manufacturing process

The manufacturing of wires and cables is completely different from that of most mechanical and electrical products. Mechanical and electrical products are usually assembled into parts or multiple parts into a single product. The products are measured by the number of units or pieces. Wires and cables are measured in length. All wires and cables are made of wire and cable products by adding insulation, shielding, cable forming and protective layer layer layer by layer outside the conductor. The more complex the product structure is, the more layers will be superimposed.

1、 Process characteristics of wire and cable manufacturing:
    1. Production mode of large length continuous superposition combination
The influence of large length continuous superposition combination production mode on wire and cable production is global and controllable, which involves and affects:

(1) Production process and equipment layout
All kinds of equipment in the production workshop must be reasonably discharged according to the process flow required by the product, so that the semi-finished products in each stage can be transferred in sequence. Equipment configuration should consider the balance of production capacity due to different production efficiency. Some equipment may have to be equipped with two or more units to balance the production capacity of the production line. Therefore, the reasonable selection and combination of equipment and the layout of production site must be balanced and comprehensively considered according to the product and production capacity.

(2) Production organization management
The production organization and management must be scientific and reasonable, thorough and accurate, strict and meticulous, and the operator must carry out it meticulously according to the process requirements. Any problem in any link will affect the smooth flow of the process and the quality and delivery of products. Especially for multi-core cables, if the length of a pair or basic unit is short, or there is a quality problem, the length of the whole cable will be insufficient, resulting in scrapping. On the contrary, if the length of a unit is too long, it must be sawed off to cause waste.

(3) Quality management
The production mode of large length continuous superposition and combination will affect the quality of the whole cable if any problem occurs in any link and instantaneously in the production process. The more quality defects occur in the inner layer, and the production is not stopped in time, the greater the loss caused. Because the production of wires and cables is different from that of assembled products, they can be disassembled, reassembled and replaced; the quality problems of any part or process of wires and cables are almost irreparable and can not be made up for. After the treatment is very negative, either saw short or degradation treatment, or scrap the whole cable. It can't be disassembled and reassembled.

The quality management of wire and cable must run through the whole production process. The quality management inspection department should patrol the whole production process, self inspection of operators and mutual inspection of upper and lower processes, which is an important guarantee and means to ensure product quality and improve economic benefits of enterprises.

2. There are many kinds of production process and large material flow
Wire and cable manufacturing involves a wide range of processes, from smelting and pressure processing of non-ferrous metals to chemical technologies such as plastics, rubber, paint, etc.; textile technologies such as fiber wrapping and weaving, to metal materials wrapping, longitudinal wrapping of metal strips, and metal forming processes of welding, etc.
There are not only many kinds, varieties and specifications of various materials used in wire and cable manufacturing, but also a large quantity. Therefore, the amount of various materials, preparation, batch cycle and batch must be approved. At the same time, as an important part of management, the decomposition treatment, recovery, reuse and waste treatment of waste products should be done well, and the material quota management should be done well, and the work of saving should be paid attention to.
In the production of wire and cable, from the import and export and storage of raw materials and various auxiliary materials, the transfer of semi-finished products in each process to the storage and delivery of products, the material flow is large, so the reasonable layout and dynamic management must be carried out.

3. Many special equipment
Wire and cable manufacturing uses special production equipment with process characteristics of the industry to adapt to the structure and performance requirements of cable products, and meet the requirements of continuous and high-speed production of large length, thus forming a series of special equipment for cable manufacturing. Such as extruder series, drawing machine series, stranding machine series, wrapping machine series, etc.
The manufacturing technology of wires and cables is closely related to the development of special equipment and promotes each other. New process requirements promote the emergence and development of new special equipment; conversely, the development of new special equipment improves the promotion and application of new technology. Such as wire drawing, annealing, extrusion series line; physical foaming production line and other special equipment, promote the development and improvement of wire and cable manufacturing process, improve the product quality and production efficiency of cable.

2、 Main technology of wire and cable
Wires and cables are made by three processes: drawing, stranding and coating. The more complex the model and specification, the higher the repeatability.

1. Control

In metal pressure processing, under the action of external force, the metal is forced to pass through the mold (pressure wheel), the metal cross-sectional area is compressed, and the required cross-sectional area shape and size is obtained.
Drawing process is divided into single wire drawing and stranding drawing.

2. Stranding
In order to improve the flexibility and integrity of wires and cables, more than two single wires are interwoven in the specified direction, which is called stranding.
Stranding process is divided into conductor stranding, cabling, weaving, steel wire armor and winding.

3. Coating

According to the different performance requirements of wires and cables, special equipment is used to coat different materials on the outer surface of conductors. The coating process includes:
A. Extrusion: rubber, plastic, lead, aluminum and other materials.
B. Longitudinal package: rubber, corrugated aluminum strip material.
C. Wrapping: ribbon tape, mica