What is the cable bundle strand? The strand is composed of multiple single wires. Generally speaking, the single wires that make up the bundle are many and thin, which not only increases the flexibility of the wire and cable, but also improves the reliability of the line connection. The conductors of some wires and cables do not require a large cross-section, but also use a stranded form, precisely for better flexibility or high reliability.

To make the single wire bundle or twist at a certain helix angle (or pitch), the equipment must meet the following requirements: one is to make all single wires rotate around the central axis of the equipment; the other is to make the stranded product straight forward movement. By changing the coordination of these two motion speeds, the size of the helix angle can be adjusted, so that the produced stranded wire or bundled wire meets the structural requirements.

The composition of the stranding machine and the bundling machine is basically the same, and they are all composed of main parts such as pay-off, traction, wire arrangement and take-up, drag and transmission system, and control system. In addition, there are also devices such as a splitter board, a parallel die (also known as a stamper), and a meter counter.

The stranding specifications produced by the stranding machine are relatively large. Except for the central single wire, the pay-off reels of the other single wires are placed in the pay-off part (such as the stranding cage), and the single wire is rotated around the central single wire to form a twist. layer. According to the number of stranded layers and the number of single wires in each layer, the general stranded machine is equipped with several (several) pay-off parts that rotate separately, so that each layer can be made into stranded wires with different twist directions. Stranded wires with concentric layers are particularly suitable. The wire harness produced by the wire harnessing machine has a small size, and it forms the wire harness by the rotation of the basket or the rotating body of the wire take-up part. Since the operation of the wire harnessing machine is in the take-up part, the speed change mechanism is installed in the rotating basket, and its position is limited, which determines that the wire harnessing machine can only be made into a product with a twisted direction and a smaller size, but the bundle The number of single wires can be flexibly configured according to needs.

The quality of stranded wire or bundled wire depends on the quality of the single wire material and the additional material on the one hand, and on the other hand, it also depends on the twisting or bundling process. The choice of stranding equipment is directly related to the structure of stranding products, the size of cross-section and outer diameter, the number of single wires, the thickness of single strands and the manufacturing length of stranding products. If it is a stranded wire with concentric layers, you should first consider whether the number and size of the pay-off reel of the stranding machine are suitable for it, and then consider the twisting direction, pitch length, and whether to reverse the twist. If it is a double-stranded wire, the deformation of the strand should also be considered, which requires analyzing the structure, specification, and material of the stranded wire, determining the process data, and finally selecting a suitable stranding machine. If it is a bundled product, in addition to the number and size of the pay-off reel, the determination of the size of the take-up reel of the wire-bundling machine is much more important than that of the stranding machine.

There are regulations on the pitch length and twist direction of various strands and bundles. The pitch length can be calculated by multiplying the outer diameter of the strand or bundle by the practical pitch ratio. In actual production, a larger pitch ratio is generally used to improve productivity as much as possible. The twisting direction must be strictly implemented according to the regulations, otherwise it will affect the connection of the line.

Stranding direction: The twisting direction of each layer of concentrically twisted wires is opposite. The twisting direction is divided into right and left directions. The axis of the twisted wire is perpendicular to the chest. If the single wire is inclined from the upper right to the lower left, is to the right, and vice versa is to the left. In order to facilitate memory, the left or right hand can be used to put the palm up, the thumb is spread apart, and the remaining four fingers are close together. direction), if the oblique direction of the left thumb is consistent with the oblique direction of the single line, it is the left direction (S direction),

In the product standard, it is not only stipulated that the interlayer laying direction of the stranded wire is opposite, but also the laying direction of the outermost layer. Generally, the outermost layer of the bare stranded wire is twisted to the right.

Twisting law: The stranded wire core is generally made of strands of the same material and diameter. In order to make the stranded wire round, and when the number of strands in the center layer is fixed, according to the arithmetic equation, each The number of layers of strands is 6.28 different than the inner layer adjacent to it, that is to say, 6.28 strands are added for each additional layer, which is generally taken as an integer of 6.

To measure the twisting pitch, use paper longer than the pitch to taut the twisted wire, and use a pencil or crayon to draw it along the axis of the twisted wire to obtain a set of imprints. The number of imprints should be more than the number of single wires in the measurement layer. Make a mark in the center of one of them, start numbering from its adjacent one, when the number of numbers is equal to the number of single lines of the measuring layer, also make a mark in the center of the last numbered impression, measure the distance between the two marks, is the pitch of the strands of this layer. For the pitch measurement of bundled wire products, since most of the bundled wires are irregularly twisted with small diameter single wires, the paper tape method cannot be used for measurement. Therefore, the actual measurement method can be used, that is, take out a section of the bundled wire product, cut off one of the surface and make a mark at the cut position, remove 10 spirals in the opposite direction of the bundled wire, and then use a ruler to measure the stranded wire of the 10 spiral parts. Length, and then divide the obtained length data by 10 to get the pitch length of the beamline.