Basic process flow of plastic wire and cable manufacturing

1. Copper and aluminum single wire drawing
Copper and aluminum rods commonly used in electric wires and cables are used to reduce the cross section, increase the length and increase the strength by drawing machine through one or several die holes of drawing dies at room temperature. Wire drawing is the first process of each wire and cable company. The main technological parameter of wire drawing is die matching technology.
2. Monofilament annealing
When heated to a certain temperature, copper and aluminum single wire can be recrystallized to improve the toughness and reduce the strength of single wire, so as to meet the requirements of wire and cable for conducting wire core. The key of annealing process is to prevent oxidation of copper wire.


3. Stranding of conductors
In order to improve the softness of wires and cables and facilitate laying and installation, the conductor core is made of several single strands. The twisted form of conductor core can be divided into regular twisted and irregular twisted. Irregular skewing can be divided into bundle skewing, concentric wringing, special skewing, etc.
In order to reduce the area occupied by the conductor and reduce the geometry size of the cable, the compact form is adopted while the conductor is twisted, so that the ordinary circle is changed into semicircle, sector, tile and compact circle. This conductor is mainly used in power cables.
4. The insulation extrusion
Plastic wire and cable mainly adopts extruded packing solid insulation layer. The main technical requirements of plastic insulation extrusion are as follows:
4.1. Eccentricity: the deviation value of extruded insulation thickness is an important symbol to reflect the level of extrusion technology. Most product structure size and deviation value are clearly stipulated in the standard.
4.2. Smoothness: the surface of the extruded insulation layer shall be smooth, and the surface shall not be rough, scorched, or contaminated
4.3. Density: The cross section of the extruded insulation layer should be compact and strong, and no visible pinholes should be allowed, so as to eliminate the existence of bubbles.


5. Cabling
In order to ensure the shape of multi-core cable and reduce the shape of cable, it is generally necessary to twist the cable into a round shape. The mechanism of stranded is similar to that of conductor stranded. The technical requirements of cable forming are as follows: first, the twisted bending of the cable caused by the turning over of the abnormal insulation core is eliminated; The second is to prevent the insulation layer from being scratched.
Most of the cables are completed with two other procedures: one is filling, which ensures the completeness and stability of the cables after cabling; One is binding to ensure that the cable core is not loose.
6. The protective layer
In order to protect the insulation core from being armored, it is necessary to properly protect the insulation layer. The inner sheath is divided into extruded inner sheath (isolation sleeve) and wound inner sheath (cushion layer). The wrapping cushion replaces the binding belt and is carried out synchronously with the cabling process.


7. Armoured
For laying underground cable, it may bear certain positive pressure during work. Internal steel tape armored structure can be selected. When cables are laid under both positive pressure and tension (such as in water, vertical shafts or in soil with a large drop), the structural type with internal steel wire armor should be selected.
8. Outer sheath
The outer sheath is the structural part that protects the insulation layer of electric wire and cable from environmental factors. The main function of the outer sheath is to improve the mechanical strength of the wire and cable, prevent chemical corrosion, moistureproof, waterproof immersion, prevent the cable from burning capacity. According to the different requirements of cable extrusion machine directly extrusion plastic sheath.

Procurement and selection of crosslinked cables

Crosslinking cable quality is high, the power frequency breakdown strength can reach 50 kv/mm, tan6 was only 5 x10-4, dielectric constant is 2.3, is the ideal cable insulation, at the same time, the working temperature of crosslinking cable up to 90 c, good heat resistance and weather resistance, and high mechanical properties and chemical properties such as corrosion resistance, in the middle and lower cable products basically have all crosslinking cable. Although the technology of crosslinked cable is different, its insulation quality is completely the same. The selection of different types of cables in common use is introduced as follows:


(1) 1 kv three core aluminum core is 70 mm ‘cross-linked polyethylene insulated PVC sheathed steel pin cables, models for YJLV22-0.6/1, 3 x70: the types of crosslinking insulation (YJ) can use any kind of crosslinking process, but to use warm water network it best, such as using dry crosslinking, the equipment investment is large, slow production, such as cable again, in the vast product line cable will be fine, or break, if use irradiation crosslinking, due to the bending times too much will make the compression of the cable conductor is impaired, press the copper conductors are easier to damage. When purchasing, it should be taken into consideration that dry crosslinking should be avoided for aluminum cable with small cross section; For large section or copper core cable can not be used to crosslink, warm water crosslink has greater flexibility.


(2) 10 kv three core copper 120 mm ‘crosslinked polyethylene insulated PVC sheathed steel tape armoured cable, models for YJV22-8.7/10, 3 x 120:10 kv level cable is larger, especially copper core cable, can’t irradiation crosslinking process, except for the bending times too much easy to damage the cable, and the insulation cimc tired space charge decreased insulation quality. At present, dry crosslinking technology is the most suitable for the production of 10kV cable, which has stable product quality and reasonable price. However, if the cable quantity is small and the specifications change a lot, dry crosslinking scrap rate is very high, and it is easy to break the cable with a small section, so warm water crosslinking should be used. Warm water crosslinking belongs to the category of low temperature crosslinking, with no insulation thermal stress and good insulation quality. To eliminate the misunderstanding of “certain water content” of warm water crosslinking, with the development of new warm water crosslinking materials, it has a very good development prospect in the field of medium and low voltage cables.
(3)10KV aluminum core 70mm overhead insulated cable, models jKLYj-6 / lO, 1×70:, this type of cable is also in the production of three technologies, using the cross linking technology of amplitude lighting. In order to eliminate space charge, after the cable conductor is grounded for a long time, the cable can be safely used in the overhead cable line of semi-insulated system. The comparison between dry crosslinking and warm water crosslinking is consistent with the above 10kV cable production.
Henan Huaxing wire and cable Co., LTD., 20 years focus on the production and customization of industrial equipment supporting cables, mainly produces power cables, control cables, flame retardant cables, fire-resistant cables, low-smoke halogen-free cables, high-temperature resistance, waterproof and other dozens of series, thousands of specifications of low-voltage cables. The products strictly comply with international standards (IEC), national standards (GB) and Machinery Ministry standards (JB), the implementation of strict production process testing and rigorous factory testing, products through CCC certification and ISO9001 quality management system certification. It is your first choice to buy wires and cables.

Production technology of wire and cable

Wires and cables are made by drawing, twisting, and cladding. The more complex the model and specification, the higher the repeatability.
A, control
In metal pressure machining, the metal cross section is compressed and the required cross section shape and size is obtained by forcing the metal through the die (pressing wheel) under the action of external force.
Drawing process is divided into single wire drawing and stranded drawing.


Second, stranding
In order to improve the softness of wires and cables, overall degree, let more than 2 single wire, according to the specified direction interweave together known as stranded.
Wring technology: conductor wring, cabling, weaving, steel wire armoring and winding.
Three, coated
According to different performance requirements for wires and cables, special equipment is used to cover the conductors with different materials. Coating process:
A. Extrusion: rubber, plastic, lead, aluminum and other materials.
B. Longitudinal bag: rubber, corrugated aluminum tape material.
C. Wrapping: strip paper tape, mica tape, alkali-free glass fiber tape, non-woven cloth, plastic tape, etc., linear cotton yarn, silk and other fiber materials.
D. Dip coating: insulating paint, asphalt, etc.

Why can’t aluminum wire cable and copper wire cable connect?

1. Copper and aluminum have different potentials. The part in contact with copper and aluminum will accelerate the oxidation of the aluminum wire due to the galvanic cell reaction. To join together, a copper – aluminum transition wire clip or transition wire pipe must be used.
2. This is a question of chemistry, the chemical properties of metals are relatively lively and not lively, such as gold, never rust, which means gold chemical inertness, easy to rust iron, iron is lively than gold, if two metal together will accelerate active metal oxide, aluminum and copper, aluminium is lively, two kinds of cable connection, will accelerate aluminum oxidation (rust), affect the use.
3. When copper and aluminum conductor are directly connected, the contact surface of the two metals is easy to form electrolyte under the action of moisture in the air, carbon dioxide and other impurities, thus forming a galvanic cell with aluminum as the negative pole and copper as the positive pole, so that aluminum produces electrochemical corrosion, resulting in the increase of the contact resistance between copper and aluminum.


In addition, due to the great difference between the elastic modulus and thermal expansion coefficient of copper and aluminum, after repeated cold and hot cycles (power on and power off) in operation, a large gap will occur at the contact point, which will affect the contact and also increase the contact resistance. The increase of contact resistance will cause the temperature to rise during operation. At high temperature, corrosion and oxidation will be intensified, resulting in a vicious cycle, which further deteriorates the quality of the connection, and finally leads to the occurrence of accidents such as smoke and burning when the temperature of the contact point is too high.


Question: Why are copper and aluminum wire clips used when connecting copper and aluminum wires?
1. The gray white material generated in the place where the copper wire and aluminum wire are connected is aluminum oxide for a little longer time. The contact resistance at the connection will increase and generate heat, resulting in on-off circuit and easy to cause building fire. So use a special copper – aluminum transition clamp. Avoid unnecessary trouble!
2. If copper wire and aluminum wire are directly hinged together, the joint is easy to oxidize, leading to increased resistance and more likely to burn out. The real reason for this damage is that aluminum is much more active than copper, and many micropotentials (i.e. microbatteries) will be generated on the copper-aluminum bonding surface, which will cause microerosion and increase the contact resistance over time. For ordinary homework, it is more reliable to connect the copper before the tin.
3. In the power system, copper and aluminum are directly connected, and electrochemical corrosion will occur when flowing through the current. Therefore, copper and aluminum should be used for transition, or tin sheets should be placed in the middle of the contact surface, and a layer of conductive paste should be applied when possible. Ordinary family connection, can be linked to copper wire tin aluminum wire, can avoid electrochemical corrosion.


Final conclusion: When the customer chooses the water pump, please look for the copper wire motor. There is a huge difference between the two. The details are as follows:
In fact, it can be summarized into two main points:
I. Price.
The price is undoubtedly cheaper than that of aluminum wire motors. Because of this, in some price wars, the products of aluminum wire motors are more than twice as cheap as those of copper wire motors, which also prompts the mass purchase of middle and low level consumers.
Ii. Quality.
Regardless of the quality of wire performance, service life, copper wire motor is superior to aluminum wire. In addition, in production, the motor embedded aluminum wire due to the quality of brittle, low toughness, easy to break, compared with the same thickness of copper wire qualified rate is lower by 30%.

Process problem of fire-resistant cable

As fire-resistant cables are used more and more widely, many manufacturers are producing them, but their quality is often not guaranteed.
Therefore, in general, enterprises in the development of fire-resistant cable products, are the first trial production of a section of products, sent to the relevant national testing institutions, after obtaining the test report, mass production.
For producing fireproof cables, if refractory test pass rate of 99%, fire-resistant cable, fire-resistant cable is 1% of the security hidden danger, the danger of this is 100% dangerous for users, how to solve these problems we will improve the passing rate of fire-resistant cable fire experiment, from raw material, conductor selection, production process control, etc, to do a description:


1. With three kinds of mica, synthetic mica, phlogopite, white mica, their performance is a synthetic mica best quality, white mica, worst for small specifications of the cable must be selected synthetic mica tape around the package, can not use the mica tape stratification, long-term storage of mica tape is easy to moisture absorption, when stored mica tape so must consider the surrounding environment of temperature and humidity.

2. When selecting mica tape wrapping equipment, good stability should be adopted and the wrapping Angle should be between 300 and 400. The mica tape wrapping equipment should be uniform and tight.
3. For a circular wire core with axial symmetry, its mica tape is tightly wound in all directions, so it is advisable to use a circular compact conductor for the conductor structure of fire-resistant cable. The reasons are as follows:


(1) some users put forward stranded conductor for beam soft conductor structure, which requires enterprises from the aspects of the reliability of the cable to use to communicate with the user to circular press conductor, soft cable structure, the complex ground mica tape damage easily, as a fire-resistant cable conductor is not desirable, but some manufacturer that users need to what kind of fireproof cables, manufacturer should meet the demand of users, I think the user after all relevant details of the cable is not very understand, cable is is closely related to people’s life, so the cable manufacturing enterprises must be related to technical issues with the user clear.
(2) The fan conductor is not suitable for use, because the fan conductor of the mica band winding pressure is not uniform distribution, from the point of view of cost of the fan conductor structure section circumference is greater than the circular conductor section circumference, thus increasing the valuable material mica band, although the circular structure of the cable diameter increased. PVC sheath material increased, but the product material compared with the total cost, the overall cost of circular structure cable is still less.
Based on the above description, from the technical and economic analysis, the circular structure of the conductor of fire-resistant power cable is the best.

Indian railways operates zero carbon

In an effort to transform India’s railways into green railways by 2030, the Ministry of Railways has taken a series of major measures to mitigate global warming and combat climate change.
Electrification of railways, improvement of energy efficiency of locomotives, trains and fixtures, green certification of installations/stations, installation of biological toilets in passenger cars and conversion to renewable energy are part of its strategy to achieve zero carbon net emissions, the Ministry said in a statement on Monday.
Indian Railways has completed more than 40,000 km (63 per cent of the wide rail line) of electrification, of which 18,605 km was completed in 2014-2020. Previously, only 3,835 km of electrification was completed between 2009 and 2014.
Indian Railways has set a target of 7,000km electrification by 2020-21. The company plans to electrify all its routes by December 2023. At the same time, the company is focusing on last-mile connectivity and electrification of the missing link. With this in mind, 365 kilometers of major connections have been made during COVID-19.

Indian Railways has also taken a number of initiatives to promote solar power, including efforts to harness 500 megawatts of energy potential through rooftop solar panels.
So far, 100 megawatts of solar power have been tested on the roofs of various buildings, including 900 power stations. In addition, solar power plants with a total installed capacity of 400 megawatts are at different stages of implementation. Bids have been awarded for 245 megawatts, and the plants are targeted for completion by December 2022.


In addition, Indian Railways is trying to generate electricity for train operations through onshore solar installations. Indian railways has 51,000 hectares of land potential for 20GW of onshore solar power plants.
In the wind sector, Indian Railways has so far been commissioning 103-megawatt wind farms. This includes 26 mw in Rajasthan, 21 mw in Tamil Nadu and 56.4 MW in Maharashtra. Indian Railways also plans to build 200 MW of wind power plants in Tamil Nadu, Gujarat, Rajasthan and Karnataka in the next two years. Aware of its role in climate change, Indian Railways has launched other green initiatives such as 100% LED lighting in buildings and stations.

The function of outer sheath of cable

Outer sheath is a protective covering covering the cable sheath (inner sheath), mainly used for mechanical strengthening and anti-corrosion. Common cables have inner sheath as the outer sheath of metal sheath and inner sheath as the outer sheath of plastic sheath.
The outer sheath of the metal sheath is generally composed of three parts: the liner layer, the armor layer and the outer quilt layer. The gasket layer is located between the metal sheath and armor layer, which plays a role of protecting gasket and metal sheath against corrosion. The armor layer is metal belt or metal wire, mainly for mechanical protection, the metal wire can withstand the tension. The metal armor is protected from corrosion by the outer layer. The cushion and outer layer of the village are composed of asphalt, polyethylene tape, impregnated paper, PVC or polyethylene sheath and other materials. According to the different use environment and conditions of various cables, its outer sheath structure is also different, the outer sheath structure of common various types of power cables are shown in the table of various types of cables.


There are two kinds of structure of outer sheath for plastic sheath. One is only PVC or polyethylene sheath without outer sheath. The other is PVC sheath extruding PVC sheath or polyethylene sheath with the same thickness as the inner sheath. Traditional PVC outer sheath Due to the low working temperature of PVC, high voltage crosslinked polyethylene (XLPE) cable with high operating temperature and protective insulation requirements is not suitable, so now high density polyethylene (CHDPE) or low density polyethylene (LLDPE) as the outer sheath has been very common, but no flame retardant. Fire prevention measures or flame retardant cables should be taken when laying. Using HDPE as the outer sheath can improve the insulation level of the sheath. The outer sheath and the corrugated metal sheath should be bonded.

Knowledge of power cord

The components of a power cord are as follows:
1. Copper wire. Copper wire is the core part of power cord. Copper wire is the carrier of current and voltage. The quality of a power cord depends on three points, namely, the density of copper wire, the material of the cord, the amount of copper wire, and the flexibility.
2. Inner sheath. Inner sheath is the material wrapped between the shielding layer and the wire core, also known as insulation sheath. The materials used are generally polyvinyl chloride plastic, polyethylene plastic or low smoke halogen-free. To ensure the safety of our power supply and prevent any leakage between copper wire and air.
3. Outer sheath. Outer sheath is the outermost protective layer (sheath) of the power cord, which plays the role of protecting the power cord. It is characterized by temperature resistance, cold resistance, oil resistance, water resistance, natural light interference, good winding performance, environmental protection, long service life.
Classification of power cord:

Power lines can be classified according to safety certification, the shape of the power cord plug and the standard of electricity consumption in different areas.
1. According to safety regulations, there are UL, CCC, VDE, PSE, SAA, UC, IRAM, IMQ, BSI, KS, PSB, SABS and so on.
2. According to the shape of the power cord plug, it can be divided into two flat power cord, three power cord, two round power cord, straight power cord, bent power cord, etc.
3. According to the standard can be divided into different parts of the electricity, the standard power cord, China standard power cord, European standard power cord, Japan standard power cord, the Australian standard power cord, the Brazilian standard power cord, Argentina standard power cord, power cord, Italy, the British standard power cord, South Korea standard power cord, standard power cord in Singapore, South Africa’s standard power cords, etc.


Manufacturing process:
Copper and aluminum single wire drawing of power cord – single wire annealing of power cord – stranded conductor of power cord – insulation extrusion of power cord – wire forming – Inner sheath of power cord – wire armor – outer sheath of power cord
Tips for identifying:
The identification method of power cord namely five look: look the quality qualification certificate of home appliance; Check the cross section of the wire; Look at the appearance of the power cord; Look at the core of the power cord; Look at the length of the power cord.
Above is a few small knowledge of power cord, hope to be helpful to everybody.

Distinguish between power cables and control cables

Power cable and control cable are widely used in people’s production and life, but many people do not know the difference between the two. Power cables are used in power system mains to transmit and distribute large functional electric energy, while control cables transmit electric energy directly from power distribution points of the power system to power connection lines of various electrical equipment and appliances. Let me show you six tips for distinguishing power cables from control cables:
Rated voltage: The rated voltage of power cable is generally 0.6/1kV and above, and the control cable is mainly 450/750V.
Ii. Insulation and sheath thickness: when producing power cables and control cables of the same specification, the insulation and sheath thickness of power cables are thicker than that of control cables.


Three, look at the implementation of the cable standard. Control cables belong to electrical equipment cables, and power cables are two of the five categories of cables. The standard of power cable is GB12706, and the standard of control cable is GB/T 9330. The flame retardant cable should also meet the technical conditions of IEC337-8 standard.
Four, look at the color of the insulation core: the insulation sleeve of each inner core of low-voltage power cable is generally color-coded; And the color of the control cable insulation core is generally black printed in white.
Five, look at the cable section. Power cable is mainly to transmit power, generally is a large section, control cable section is generally not more than 10 square. Power cable specifications can generally be large, up to 500 square; The control cable section is generally small, the maximum is generally not more than 10 square.
The above is the introduction of the method to distinguish power cable and control cable, hoping to help you better complete the selection of cable.

British-French submarine cable preparation

Crosslake Fiber, a developer and operator of communications networks in North America and Western Europe, revealed its latest submarine cable project, called CrossChannel Fibre, which is a submarine cable system connecting Slough, United Kingdom and Paris, France, with a total length of approximately 550 kilometers.
According to the plan, the system will contain 96 pairs of optical fibers, each pair of optical fibers provides more than 20Tbps of capacity. To support the project, Crosslake Fiber has authorized EGS, the world’s leading ocean survey and service provider, to conduct project maritime surveys.


In addition, Tiger Infrastructure Partners, the capital partner of Crosslake Fibre, has invested additional capital in the Crosslake platform to support the CrossChannel Fiber system.
Mike Cunningham, CEO of Crosslake Fibre, said, “We are very pleased to launch this historic submarine project and provide a new connection in the crucial data center connecting Slough in the English Channel with Paris. This new The optical fiber infrastructure has been optimized to establish the shortest path between the two data, providing users with enhanced technical solutions and greatly reducing operating costs. With the COVID-19 pandemic, the continuous increase in bandwidth demand has continued to increase The submarine cable has never been so important to the function of the Internet backbone.”
According to the plan, the submarine cable system will be put into use in the fall of 2021 (RFS).