Basic wire and cable knowledge

Basic wire and cable knowledge

The manufacturing of wire and cable is completely different from that of most mechanical and electrical products. Mechanical and Electrical Products are usually assembled into parts, multiple parts are installed into a single product, the product is measured in the number of units or pieces. Wire and cable are measured in length. All wire and cable products are made from wire and cable processing, and insulation, shielding, cables, and protective layers are added on the outer layer of the conductor. The more complex the product structure is, the more layers there are.

I. Manufacturing Process Characteristics of wire and cable products　

1. Large-length continuous overlapping production mode

The impact on the production of wire and cable is global and controllable in the production of large-length continuous overlapping combinations, which involves and influences:

(1) Production Process and Equipment Layout

Various 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. The production capacity should be balanced based on different production efficiency. Some equipment may have to be configured with two or more units to balance the production capacity of the production line. Therefore, the reasonable combination of equipment and the layout of production sites must be balanced and considered based on the product and production capacity.

(2) Production Organization Management

The production organization and management must be scientific, reasonable, accurate, and strict, and the operator must be meticulous in accordance with the process requirements. Any problem in any link will affect the smooth process, affects product quality and delivery. In particular, if the length of a single cable or basic unit is short or the quality is faulty, the length of the whole cable is insufficient, resulting in decommission. If the length of a unit is too long, sawing is required to cause waste.

(3) Quality Management

The production method of the large-length continuous overlapping combination will affect the quality of the entire cable if any link in the production process has an instantaneous problem. The more internal quality defects occur and production is not found in time, the greater the loss. Because wire and cable production is different from assembly-type products, you can disassemble and reload and replace other parts; any part of the wire and cable or quality problems in the process, this cable is almost irreparable and irreparable. The post-event handling is very negative. The whole cable is either degraded or scrapped. It cannot be disassembled and reinstalled.

Quality Management of wires and cables must be implemented throughout the entire production process. The quality management and inspection department should inspect the whole production process, perform operator self-check, and check the upstream and downstream processes. This is an important guarantee and means to ensure the product quality and improve the economic efficiency of enterprises.

2. Many production processes and Large Material Flow

Wire and cable manufacturing involves a wide range of technology categories, from smelting and pressure processing of non-ferrous metals to chemical technology such as plastics, rubber, paint; textile technology such as wrapping and weaving of fiber materials, to the metal material package and Metal Strip longitudinal package, welding metal forming process and so on.

Various Materials Used in wire and cable manufacturing, including categories, varieties, and specifications, are large in quantity. Therefore, the usage, backup volume, approval cycle and batch of various materials must be verified. At the same time, the decomposition, recycling, reuse and waste disposal of waste products are an important part of management, so as to manage material quotas and pay attention to conservation.

In the production of wire and cable, the transfer of semi-finished products in various processes from raw materials and various auxiliary materials to the storage and delivery of products requires a reasonable layout and dynamic management.

3. Many dedicated devices

Wire and cable manufacturing uses dedicated production equipment with technical characteristics of the industry to adapt to the structure and performance requirements of cable products, to meet the requirements of continuous production of large length and as high speed as possible, thus forming a series of dedicated equipment for cable manufacturing. Such as extrusion machine series, cable pulling machine series, stringing Machine Series, and winding machine series.

The manufacturing process of wire and cable is closely related to the development of special equipment and promote each other. New technology requirements promote the generation and development of new dedicated equipment. In turn, the development of new dedicated equipment has promoted the promotion and application of new technology. Such as wire drawing, annealing, extrusion series line, physical foam production line and other special equipment, promote the development and improvement of the wire and cable manufacturing process, and improve the cable product quality and production efficiency.

Ii. Main Technology of wire and cable

Wire and cable are produced by three processes: pulling, twisting, and coating. The more complex the model and specification, the higher the repeatability.

1. Pull

In metal pressure processing. the metal is forced by external force through the mold (wheel), the metal cross-sectional area is compressed, and the required cross-sectional area shape and size of the technical processing method is called metal pull.

Pull process: single-wire pull and twisted pull.

2. Twisted

In order to improve the flexibility and overall degree of wire and cable, more than two single lines are intertwined in the specified direction.

The stringing process is divided into conductor stringing, cable forming, weaving, wire mounting, and winding.

3. Coating

According to different performance requirements on wire and cable, use special equipment to enclose different materials outside the conductor. Coating Process score:

• Packing: rubber, plastic, lead, aluminum and other materials.
• Longitudinal bag: rubber, Wrinkle Aluminum belt material.
• Wrap: tape, mica tape, alkali-free fiberglass tape, non-woven fabrics, plastic tape, and other fiber materials such as linear cotton yarn and silk.
• Dip coating: Insulating Paint, asphalt, etc.

3. Basic Process of plastic wire and cable Manufacturing

1. copper and aluminum single wire drawing

Commonly used copper and aluminum Rod Materials for wire and cable. at normal temperature, the cross section is reduced, the length is increased, and the strength is increased by drawing one or more die holes. Wire Drawing is the first process of various wire and cable companies. The main process parameter of wire drawing is the pattern configuration technology.

2. Single-wire Annealing

When copper and aluminum monofilament are heated to a certain temperature, the toughness of monofilament can be improved by recrystallization, and the strength of monofilament can be reduced to meet the requirements of conductive wire cores of wire and cable. The key to the annealing process is to prevent oxidation of copper wires.

3. Stranded Conductor

In order to improve the flexibility of wire and cable, and facilitate installation, the conductive wire core is twisted with multiple single wires. From the form of stranded conductive wire core, it can be divided into rule-based and non-rule-based. Irregular twisting can be divided into bundle twisting, concentric twisting, and special twisting.

In order to reduce the occupied area of the wire and reduce the geometric size of the cable, compress the normal circular shape into a circular shape, such as semi-circular, slice-shaped, tile-shaped, and compact. This conductor is mainly used in power cables.

4. Insulation Extrusion

Plastic wire and cable are mainly filled with solid insulation, plastic insulation extrusion of the main technical requirements:

• Eccentric degree: The deviation value of the insulation thickness of extrusion is an important indicator of the extrusion process level. The structure size and deviation value of most products are clearly defined in the standard.
• Smoothness: the surface of the extruded insulation layer must be smooth, and there should be no bad quality problems such as rough surface, burning and impurity.
• Density: The cross section of the extrusion insulation layer should be dense and firm, and there is no visible pinhole to prevent the existence of bubbles.

5. cabling

For multi-core cables, in order to ensure the forming degree and reduce the cable shape, it is generally required to be twisted into a circular shape. The mechanism of twisting is similar to that of the conductor. Most of the twisting methods are not used due to the large size of the twisting joint. Cable forming technical requirements: first, to prevent the bending of the cable Caused by the turning of the special-shaped insulation wire core; second, to prevent the insulation layer from being scratched.

Most of the cables are completed along with the other two processes at the same time: one is filling to ensure the consolidation and stability of the cables after the cables are formed; the other is bundling to ensure that the cables are not loose.

6. Internal Protection Layer

In order to protect the insulation core from being damaged by armor, the insulation layer should be properly protected. The internal protection layer should be divided into: the inside protection layer (isolation sleeve) and the inside protection layer (cushion ). The wrapping cushion replaces the binding belt and works in synchronization with the Cabling Process.

7. Install volume

Laid in the underground cable, may bear a certain amount of positive pressure, you can choose the steel armor structure. Cables are laid in situations with both positive pressure and tension (such as water, vertical shafts or soil with a large gap), and should be made of structural cables with internal steel armor.

8. Outer Jacket

The outer sheath is the structural part that protects the insulation layer of wire and cable from environmental erosion. The main function of the outer sheath is to improve the mechanical strength, chemical corrosion prevention, moisture resistance, water immersion, and prevent the burning of cables. Use the extruder to directly pack the plastic jacket according to different requirements of cables.