First, the concept of cable formation

The concept of cabling: The process of stranding a synthetic cable with multiple insulated wire cores according to certain rules.

Second, the meaning of cable formation

Cable is one of the important processes in the production of multi-core cables, power cables commonly used three-phase power supply of three core, four core (one core is the ground wire) and five core (one core is the ground wire, and one core is the neutral wire) cable, the number of control cable cores is more (more than 2 core to 61 core), the cable process is a number of insulated wire cores according to certain rules and certain twisted to twisted together. The process of forming a multi-core cable. In addition to stranding, the cabling process also includes the filling of the space between the insulated wire cores and the wrapping and shielding of the cable cores after the cabling process.

When forming cables, the stranded form of the insulated wire core adopts concentric regular stranded, and if the cable with the same diameter of the insulated wire core is called symmetrical cable. If the insulated wire core diameter is not the same, the cable is called asymmetric cable. In order to avoid the effect of torsional stress on the insulated wire core in the process of cabling, the round insulated wire core is made by using the cabling machine with untwisting device or the bow forming machine for untwisting and stranding.

Third, the way of stranding cable

There are two ways of stranding and cable stranding, one is untwisted and the other is untwisted.

Untwisted twist is the wire tray with pay-off tray with its special device (untwisted device) in the machine rotation, so that the pay-off tray always maintain a horizontal position, in the cable, the insulation core is only subject to bending action, but not twisting action. Untwisting and stranding is often used in the cabling process of circular insulated wire core. After cabling, the wire core has no rebound stress, which can ensure the accuracy of the roundness and the diameter of the cable.

The non-return twisting is mostly used for the formation of the fan line, which becomes plastic deformation after the pressing of the press die, thereby eliminating the original torsion stress and ensuring the roundness of the cable after the cable is formed.

Four, cable direction and pitch diameter ratio

The direction of cable formation is generally right. The direction of the cable is confirmed by the direction of the cable core, if the skein cage to the left is right, otherwise the reverse.

The cable pitch diameter ratio varies according to different types of cables. The round core of cross-linked polyethylene insulation has a larger cable pitch diameter due to hard insulation, and a disc is 30~40; PVC insulated power cable circular core cable pitch diameter ratio is also 30~40, fan line pitch diameter ratio is 40~50; Plastic insulated control cable core diameter ratio is stipulated in the national standard, generally not greater than 16~20.

5. Stranding coefficient and stranding rate

In one pitch of the cable, the ratio of the actual length of the insulated wire core to the length of the cable pitch is called the stranding coefficient (K=L/H);

The stranding rate is the ratio of the difference between the actual length of the insulated core and the length of the cable pitch to the length of the cable pitch: λ=(L-H)/H×100%

It is more convenient to use the stranding coefficient K, and the K value is always greater than 1, so that after the cable is formed, the actual length of the single insulated wire core increases by a K value, and the resistance of the wire core is proportional to the wire core, that is, the resistance of the wire core also increases by a K value. The insulation resistance is inversely proportional to the length of the insulated wire core, and the insulation resistance of each insulated wire core is reduced by a K value. From the Angle of reducing the resistance value of the wire core and increasing the insulation resistance value, it is hoped that the smaller the stranding coefficient of the cable is the better.

The stranding coefficient is inversely proportional to the square of the pitch ratio. Therefore, the smaller the pitch ratio is, the larger the stranding coefficient is, and the larger the amount of insulating core material is. Otherwise, from the perspective of saving the amount of material, the smaller the stranding coefficient is expected to be.

Six, wrapping process

The production process of wrapping conductive cable core or cable core with various metal or non-metal materials in a band or linear form in a specified pitch spiral shape is the lapping process.

Seven, non-armored cable cable wrap

In order to no longer deform the cable core after the cable is formed, and in order to prevent adhesion with the sheath to play an isolation role, the insulated wire core in the cable forming machine is formed and filled at the same time, it is also necessary to wrap the tape layer. For non-armored plastic insulated cables, the tape is usually wrapped by 1 to 2 layers of non-woven tape with the cover wrapping method (specifically, with one layer or two layers, the cable wrapping is the principle). The cover size is 10% to 15% of the bandwidth, and the wrapping Angle is in the range of 25° to 40°.

8. Armoring of cables

Steel tape armored cable is mainly suitable for underground direct burial, can withstand a certain mechanical pressure; Steel wire armored cable is mainly suitable for a drop or vertical laying, can withstand large mechanical tension. Armored cables are mainly divided into two kinds of steel tape armored and steel wire armored, and their combination armored way.

If there is shielding material (including blanket shielding) on the insulated wire core of the steel tape armored cable, the cable core adopts extruded insulation sheath instead of the inner coating layer. If the insulated wire core has no metal shielding layer, the inner coating layer can be extruded or wrapped. The inner layer of wrapping is generally made of PVC or PE and other similar strips.

Steel wire armored cables generally use extruded inner coating.

Armored cable models such as YJV22 will appear two numbers, the first number is the armored code: generally there are 2, 3, 4 three numbers:

2 -- indicates double-layer steel tape armoring

3 -- indicates fine wire armouring

4 -- denotes thick steel wire armouring

The thickness of the steel tape and copper gap of the armored cable, the diameter of the steel wire and the gap of the steel wire armored cable shall meet the provisions of the relevant standards.

Qingdao Tianxing Cable Co., Ltd. is a technology enterprise specializing in the production of wire and cable in Shandong Province, with more than 150 sets of domestic excellent cable production equipment and testing equipment, excellent production technology, modern testing equipment, to ensure stable product quality and timely supply. The company's main products are power cable, mineral cable, high life wire and cable, radiation crosslinked cable, control cable, computer cable, photovoltaic cable, communication cable, data cable, low smoke halogen free cable, flame retardant series wire and cable.