Experts teach you the basic knowledge of wires and cables.

At present, there are many kinds of wires sold in the market, among which some inferior products are mixed, which seriously affect our electricity safety and bury long-term hidden dangers in our lives. Let's get to know the wires today!

The manufacture of wires and cables is completely different from most mechanical and electrical products. Mechanical and electrical products usually adopt the method of assembling another part into a part and assembling multiple parts into a single product, and the products are measured by unit or number. Wires and cables are based on length. All wires and cables are made of conductors, and insulation, shielding, wiring and protective layers are added layer by layer around the conductors. The more complex the product structure, the more layers are superimposed.

A, wire and cable products manufacturing process characteristics:

1. Large-length continuous superposition combined production mode

The combined production mode of long-length continuous superposition has an overall and controlling influence on wire and cable production, involving and influencing:

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(1) production technology and equipment layout

All kinds of equipment in the production workshop must be reasonably discharged according to the technological process required by the product.

Make the semi-finished products of each stage flow in sequence. Equipment configuration should consider different production efficiency and balance production capacity. Some equipment may need 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 sites must be balanced and comprehensively considered according to products and production. (2) Production organization and management

Production organization and management must be scientific, reasonable, thorough, accurate, strict and meticulous, and operators must operate in strict accordance with technological requirements. Problems in any link will affect the smooth process and the quality and delivery of products. Especially for multi-core cables, if the length of one pair or basic unit is short, or there are quality problems, the whole cable will be short and scrapped. On the other hand, if a unit is too long, it must be sawed off, resulting in waste.

(3) Quality control

The production mode of long-length continuous superposition and combination makes any link and transient problem in the production process affect the quality of the whole cable. The more inner quality defects, the greater the loss if production is not stopped in time. Because the production of wire and cable is different from the assembled product, it can be disassembled and reassembled and replaced with another one; The quality problem of any part or process of wire and cable is almost irreparable for this kind of cable. The post-treatment is very negative, either sawing short or degrading, or scrapping the whole cable. It cannot be disassembled and reassembled.

The quality control of wires and cables must run through the whole production process. Quality control and inspection departments should patrol the whole production process, operators should conduct self-inspection and mutual inspection between 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 processes and a large amount of logistics.

Wire and cable manufacturing involves a variety of processes, from smelting and pressure processing of non-ferrous metals to chemical technologies such as plastics, rubber and paint. Textile technologies such as wrapping and weaving of fiber materials, wrapping of metal materials and longitudinal wrapping of metal strips, and welding metal forming and processing technology.

All kinds of materials used in wire and cable manufacturing are not only of many kinds, varieties and specifications, but also of large quantity. Therefore, the quantity, spare capacity, batch cycle and batch number of various materials must be approved. At the same time, as an important part of management, we should do a good job in the decomposition, recovery, reuse and waste disposal of waste products, and attach importance to saving.

In wire and cable production, from the import and export and storage of raw materials and various auxiliary materials, to the circulation of semi-finished products in each process, and then to the storage and delivery of products, the logistics volume is large, which must be rationally distributed and dynamically managed.

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There are many special equipments.

Wire and cable manufacturing adopts special production equipment with the process characteristics of the industry to meet the structural and performance requirements of cable products and meet the requirements of long-length continuous and high-speed production as much as possible, thus forming a series of special equipment for cable manufacturing. Such as extruder series, wire drawing machine series, stranding machine series, winding machine series and so on.

The manufacturing technology of wire and cable is closely related to the development of special equipment and promotes each other. New technical requirements have promoted the emergence and development of new special equipment; On the other hand, the development of new special equipment promotes the popularization and application of new technologies. Such as wire drawing, annealing and extrusion; Special equipment such as physical foaming production line promotes the development and perfection of wire and cable manufacturing technology, and improves the product quality and production efficiency of cables.

Second, the main process of wire and cable

Wires and cables are made by three processes: stretching, twisting and coating. The more complex the specification, the higher the repeatability.

1. Picture

In metal pressure machining, the metal is forced to pass through the die (press wheel) under the action of external force, and the cross-sectional area of the metal is compressed to obtain the required cross-sectional area shape and size. This technical processing method is called metal drawing.

The drawing process is divided into monofilament drawing and stranded drawing.

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In order to improve the flexibility and integrity of wires and cables, more than two single wires are intertwined in a specified direction, which is called twisting.

The twisting process is divided into conductor twisting, cabling, weaving, steel wire armoring and winding.

Success wisdom wiring

overcoat

According to the different performance requirements of wires and cables, special equipment is used to wrap conductors with different materials. The coating process is divided into:

A. packaging: rubber, plastic, lead, aluminum and other materials.

B. longitudinal packaging: rubber and corrugated aluminum strip materials.

C wrapping: ribbon paper tape, mica tape, alkali-free glass fiber tape, non-woven fabric, plastic tape, linear cotton yarn, silk and other fiber materials.

D. dip coating: insulating paint, asphalt, etc.

Third, the basic process of plastic wire and cable manufacturing

1. Copper-aluminum monofilament drawing

Copper-aluminum rods commonly used for wires and cables pass through one or more die holes of the wire drawing die at room temperature, so that the cross section is reduced, the length is increased and the strength is improved. Wire drawing is the first process of wire and cable enterprises, and the main technological parameter of wire drawing is die matching technology.

2. Monofilament annealing

Copper-aluminum monofilament is heated to a certain temperature, and the toughness is improved and the strength of monofilament is reduced by recrystallization to meet the requirements of wire and cable for conductive core. The key of annealing process is to prevent copper wire from oxidation.

3. Stranding of conductors

In order to improve the flexibility of wires and cables and facilitate laying and installation, the conductive wire core is twisted by multiple monofilaments. According to the stranded form of conductive wire core, it can be divided into regular stranded and irregular stranded. Irregular twisting is divided into bundle twisting, concentric double twisting and special twisting.

In order to reduce the occupied area of the conductor and the geometric size of the cable, the common circle is transformed into semi-circle, fan-shaped, tile-shaped and tight-pressed circle while twisting the conductor. This conductor is mainly used for power cables.

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4. Insulation extrusion

Plastic wires and cables mainly use extruded solid insulation layer. The main technical requirements for plastic insulation extrusion are as follows:

4. 1. Eccentricity: The deviation value of extrusion insulation layer thickness is an important symbol reflecting the extrusion process level, and the structural dimensions and deviation values of most products are clearly specified in the standard.

4.2. Smoothness: The surface of the extruded insulation layer shall be smooth, and there shall be no bad quality problems such as rough surface, scorch and impurities.

4.3. Densification: The section of the extruded insulating layer should be dense and firm, and there should be no pinholes visible to the naked eye to prevent bubbles.

5. Wiring

In order to ensure the molding degree and reduce the shape of multi-core cable, it is generally necessary to twist multi-core cable into a circle. The mechanism of twisting is similar to that of conductor twisting. Because of the large diameter of twisting, most of them adopt the untwisted method. Technical requirements for cable formation: first, prevent the cable from twisting and bending due to turning over the special-shaped insulated wire core; The second is to prevent the insulating layer from being scratched.

Most cables are completed at the same time as the other two processes: one is filling to ensure the roundness and stability of the cable after completion; One is binding to ensure that the cable core is not loose.

6. Inner protective layer

In order to protect the insulated wire core from being damaged by armor, it is necessary to properly protect the insulation layer. The inner protective layer is divided into extruded inner protective layer (insulating sleeve) and wrapped inner protective layer (cushion layer). The wrapping pad replaces the binding tape and is synchronized with the cable forming process.

7. armored

Cables laid underground may bear a certain positive pressure when working, so the inner steel belt armored structure can be selected. When laying cables in places with both positive pressure and tension (such as water, shaft or soil with large drop), the structure type of inner steel wire armor should be selected.

8. External sheath

The outer sheath is a structural component to protect the insulation layer of wires and cables from environmental factors. The main function of the outer sheath is to improve the mechanical strength of wires and cables, prevent chemical corrosion, prevent moisture, prevent people from soaking in water and prevent cables from burning. According to the different requirements of cables, the plastic sheath is directly extruded by an extruder.

Desai electric cable

Home improvement is inseparable from wires, especially old houses. Although the wire is small, it is "responsible". Many fires are caused by aging wires, unreasonable configuration, or poor quality of used wires. Therefore, consumers must polish their eyes when buying wires, carefully identify them, and prevent problems before they happen.

turn around

In order to improve the flexibility and integrity of wires and cables, more than two single wires are intertwined in a specified direction, which is called twisting.

The twisting process is divided into conductor twisting, cabling, weaving, steel wire armoring and winding.

Success wisdom wiring

overcoat

According to the different performance requirements of wires and cables, special equipment is used to wrap conductors with different materials. The coating process is divided into:

A. Extrusion: rubber, plastic, lead, aluminum and other materials.

B. longitudinal packaging: rubber and corrugated aluminum strip materials.

C wrapping: ribbon paper tape, mica tape, alkali-free glass fiber tape, non-woven fabric, plastic tape, linear cotton yarn, silk and other fiber materials.

D. dip coating: insulating paint, asphalt, etc.

Third, the basic process of plastic wire and cable manufacturing

1. Copper-aluminum monofilament drawing

Copper-aluminum rods commonly used for wires and cables pass through one or more die holes of the wire drawing die at room temperature, so that the cross section is reduced, the length is increased and the strength is improved. Wire drawing is the first process of wire and cable enterprises, and the main technological parameter of wire drawing is die matching technology.

2. Monofilament annealing

Copper-aluminum monofilament is heated to a certain temperature, and the toughness is improved and the strength of monofilament is reduced by recrystallization to meet the requirements of wire and cable for conductive core. The key of annealing process is to prevent copper wire from oxidation.

3. Stranding of conductors

In order to improve the flexibility of wires and cables and facilitate laying and installation, the conductive wire core is twisted by multiple monofilaments. According to the stranded form of conductive wire core, it can be divided into regular stranded and irregular stranded. Irregular twisting is divided into bundle twisting, concentric double twisting and special twisting.

In order to reduce the occupied area of the conductor and the geometric size of the cable, the common circle is transformed into semi-circle, fan-shaped, tile-shaped and tight-pressed circle while twisting the conductor. This conductor is mainly used for power cables.

Desai electric cable

4. Insulation extrusion

Plastic wires and cables mainly use extruded solid insulation layer. The main technical requirements for plastic insulation extrusion are as follows:

4. 1. Eccentricity: The deviation value of extrusion insulation layer thickness is an important symbol reflecting the extrusion process level, and the structural dimensions and deviation values of most products are clearly specified in the standard.

4.2. Smoothness: The surface of the extruded insulation layer shall be smooth, and there shall be no bad quality problems such as rough surface, scorch and impurities.

4.3. Densification: The section of the extruded insulating layer should be dense and firm, and there should be no pinholes visible to the naked eye to prevent bubbles.

5. Wiring

In order to ensure the molding degree and reduce the shape of multi-core cable, it is generally necessary to twist multi-core cable into a circle. The mechanism of twisting is similar to that of conductor twisting. Because of the large diameter of twisting, most of them adopt the untwisted method. Technical requirements for cable formation: first, prevent the cable from twisting and bending due to turning over the special-shaped insulated wire core; The second is to prevent the insulating layer from being scratched.

Most cables are completed at the same time as the other two processes: one is filling to ensure the roundness and stability of the cable after completion; One is binding to ensure that the cable core is not loose.

6. Inner protective layer

In order to protect the insulated wire core from being damaged by armor, it is necessary to properly protect the insulation layer. The inner protective layer is divided into extruded inner protective layer (insulating sleeve) and wrapped inner protective layer (cushion layer). The wrapping pad replaces the binding tape and is synchronized with the cable forming process.

7. armored

Cables laid underground may bear a certain positive pressure when working, so the inner steel belt armored structure can be selected. When laying cables in places with both positive pressure and tension (such as water, shaft or soil with large drop), the structure type of inner steel wire armor should be selected.

8. External sheath

The outer sheath is a structural component to protect the insulation layer of wires and cables from environmental factors. The main function of the outer sheath is to improve the mechanical strength of wires and cables, prevent chemical corrosion, prevent moisture, prevent people from soaking in water and prevent cables from burning. According to the different requirements of cables, the plastic sheath is directly extruded by an extruder.

Desai electric cable

Home improvement is inseparable from wires, especially old houses. Although the wire is small, it is "responsible". Many fires are caused by aging wires, unreasonable configuration, or poor quality of used wires. Therefore, consumers must polish their eyes when buying wires, carefully identify them, and prevent problems before they happen.