Manufacturing process of wire and cable and main equipment required

Author：hlyb Add Time：2016-07-11 10:38:13

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 by another part, and then assembled into a single product by multiple parts. The products are measured by the number of sets or pieces. The basic unit of measurement of wire and cable is length. All wires and cables are made of wire and cable products by adding insulation, shielding, cabling, protective layer, etc. layer by layer on the periphery of the conductor. The more complex the product structure is, the more layers are superimposed.

1、 Manufacturing process characteristics of wire and cable products:

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

(1) Production process flow and equipment layout

All kinds of equipment in the production workshop must be properly discharged according to the process flow required by the product, so that the semi-finished products in each stage can be transferred in sequence. For equipment configuration, the production capacity shall be balanced considering different production efficiency. Some equipment may have to be configured with two or more 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 products and production capacity.

(2) Production organization management

The production organization and management must be scientific, reasonable, thorough, accurate, strict and meticulous. The operator must strictly implement the process requirements. Any problem in any link will affect the smoothness of the process flow 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 sawn off, resulting in waste

(3) Quality management

The production mode of continuous superposition and combination of large length will cause a problem in any link and instant in the production process, which will affect the quality of the whole cable. The more quality defects occur in the inner layer and are not found in time to stop production, the greater the loss. Because the production of wires and cables is different from assembled products, they can be disassembled, reassembled and replaced; The quality problem of any part or process of wire and cable is almost irreparable and irreparable to this cable. The subsequent treatment is very negative, either sawing short or degrading treatment, or scrapping the whole cable. It cannot be disassembled and reassembled.

The quality management of wires and cables must run through the whole production process. The quality management inspection department shall conduct patrol inspection, operator self inspection and mutual inspection of upper and lower processes throughout the production process, which is an important guarantee and means to ensure product quality and improve the economic benefits of the enterprise.

2. There are many production processes 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 and paint; Textile technology such as wrapping and weaving of fiber materials, wrapping of metal materials, longitudinal wrapping of metal strip, metal forming and processing technology of welding, etc. All kinds of materials used in the manufacture of wires and cables not only have many categories, varieties and specifications, but also have a large number. Therefore, the consumption, reserve consumption, batch cycle and batch of various materials must be approved by * * *. At the same time, the decomposition, recycling, reuse and waste disposal of waste products, as an important content of management, do a good job in material quota management and pay attention to saving.

In the production of wire and cable, from the import and export and storage of raw materials and various auxiliary materials, the circulation of semi-finished products in each process to the storage and delivery of products, the material flow is large, so it is necessary to make reasonable layout and dynamic management.

3. Many special equipment

Wire and cable manufacturing uses special production equipment with process characteristics of the industry to meet the structure and performance requirements of cable products and meet the requirements of large-length continuous and high-speed production as much as possible, 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 to promote the emergence and development of new special equipment; On the contrary, the development of new special equipment has improved and promoted the popularization and application of the new process. Such as wire drawing, annealing, extrusion series line; Special equipment such as physical foaming production line promotes the development and improvement of wire and cable manufacturing process, and improves the product quality and production efficiency of cable.

2、 Main process of wire and cable

Wires and cables are manufactured through three processes: drawing, twisting and coating. The more complex the model and specification, the higher the repeatability.

1. Drawing

In metal pressure machining Under the action of external force, the metal is forced through the die (pressing wheel), the metal cross-sectional area is compressed, and the required cross-sectional area shape and size are obtained. The technical processing method is called metal drawing.

Drawing process is divided into single wire drawing and twisted drawing.

2. Stranding

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

Stranding process includes conductor stranding, cabling, weaving, steel wire armor and winding.

3. Coating

According to different performance requirements for wires and cables, special equipment is used to coat different materials on the outside of the conductor.

Coating process points:

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

B. Longitudinal package: rubber, wrinkled aluminum strip material.

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

3、 Basic process flow of plastic wire and cable manufacturing

1. Copper and aluminum single wire drawing

The copper and aluminum rods commonly used for wires and cables can reduce the section, increase the length and improve the strength by using the wire drawing machine to pass through the die holes of one or several drawing dies at room temperature. Wire drawing is the first process of wire and cable companies, and the main process parameter of wire drawing is die matching technology.

2. Monofilament annealing

When the copper and aluminum monofilament is heated to a certain temperature, the toughness of the monofilament is improved and the strength of the monofilament is reduced by recrystallization, so as to meet the requirements of wires and cables for conductor cores. The key of annealing process is to eliminate the oxidation of copper wire

3. Stranding of conductor

In order to improve the flexibility of wires and cables and facilitate laying and installation, the conductive wire core is twisted by multiple single wires. From the stranding form of conductor core, it can be divided into regular stranding and irregular stranding. Irregular stranding is divided into bundle stranding, concentric compound stranding, special stranding, etc. In order to reduce the occupied area of the conductor and reduce the geometric size of the cable, the compact form is adopted while stranding the conductor, so that the ordinary circle can be changed into a semicircle, fan-shaped, tile shaped and compact circle. This kind of conductor is mainly used in power cables.

4. Insulation extrusion

Extruded solid insulation layer is mainly used for plastic wires and cables. The main technical requirements of plastic insulation extrusion are as follows:

(1) Eccentricity: the deviation value of the extruded insulation thickness is an important sign of the extrusion process level. Most product structure dimensions and their deviation values are clearly specified in the standard.

(2) Smoothness: the surface of the extruded insulating layer shall be smooth without surface roughness, scorching and impurities

(3) Density: the cross section of the extruded insulating layer shall be dense and solid, and there shall be no needle holes visible to the naked eye, so as to eliminate the existence of bubbles.

5. Cabling

For multi-core cables, it is generally necessary to twist them into a circle in order to ensure the formability and reduce the shape of the cable. The mechanism of stranding and the technical requirements of conductor stranding into cable: first, eliminate the twisting of cable caused by turning over of special-shaped insulating core; The second is to prevent the insulating layer from being scratched. Most cables are completed with the completion of two other processes: one is filling to ensure the roundness and stability of cables after cable completion; One is binding to ensure that the cable core is not loose.

6. Inner sheath

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

7. Armor

If the cable is laid underground, it may bear certain positive pressure during work, and the inner steel strip armored structure can be selected. When the cable is laid under both positive pressure and tension (such as in water, vertical shaft or soil with large drop), the structural type with inner steel wire armor shall be selected.

8. Outer sheath

The outer sheath is a structural part to protect the insulating layer of wires and cables from environmental factors. The main function of the outer sheath is to improve the mechanical strength, chemical corrosion prevention, moisture-proof, water-proof and human immersion of wires and cables, and prevent cable combustion. According to different requirements for cables, the plastic sheath is directly extruded by extruder.

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Manufacturing process of wire and cable and main equipment required