Production process details of steel wire armored control cables

In the past two years, our factory has produced a large number of domestic and export steel wire armored cables. For mass production of this type of cable, both the process and the technical level of the operators are quite mature. However, when producing longer length steel wire armored cables, we often encounter the phenomenon of steel wire lifting lanterns, which brings a lot of trouble to production and sales. After our on-site exploration and careful summary, we believe that the following issues should be noted when producing steel wire armored cables:

1. Cable laying process

For the steel wire armor of three core cables, the cable must be round and the tension of the insulated wire core must be adjusted evenly, which lays a good foundation for the next steel wire armor process. Due to the small contact area between the steel wire and the cable core during steel wire armor, the steel wire exerts an inward pressure on the cable core. If the tension adjustment of the insulated wire core is not uniform, the cable may not be round and smooth. This can easily cause the steel wire to become loose, lantern shaped, and not round during steel wire armor, resulting in uneven wire after armor. This can cause problems for finished product coiling and user installation. Therefore, manufacturers must pay attention to the cable forming process when producing steel wire armor. Especially during cable formation, special attention should be paid to using traction wires with the same outer diameter at the beginning and end of the insulated wire core. This ensures that the insulated wire core and the cable core wire are always under tension during cable formation, so that the cable core wire will not generate internal stress and will not show internal stress during steel wire armor;

2. Steel wire armor (taking 2.5-meter or 3.15-meter tracked traction disc winch as an example)

① Firstly, the wire unwinding wheel must have tension and the tension can be adjusted;

② The diameter of the steel wire is selected based on the assumed diameter of the cable, and the number of steel wires is determined based on the theoretical calculation of the outer diameter of the cable. In the actual production process, the number of steel wires can be adjusted by adding or subtracting 1-2 wires according to the actual outer diameter of the cable core. Once the number of wires is determined, the number of cables produced in this batch will be determined. When filling in the technical parameters for foreign cable bidding, the diameter of the steel wire can be directly filled in, but the number of wires cannot be filled in as a fixed value. There is a condition of ± 2 wires, which allows the manufacturer to have adjustment flexibility in the actual production process;

③ The wire must be evenly divided on the dividing plate, and when entering the merging mold, the wire passes through a pre forming device with a shape of ∽, and the distance of ∽ must be adapted to the pitch of the wire;

④ The wire drawing mold must be made of steel mold material with an inner hole roughness of 0.025. The inner hole size should not be too large or too small. If it is too large, the tightness of the steel wire will be poor, and if it is too small, it will increase the traction force of the steel wire. The steel wire cannot run smoothly and continuously, and it is easy to damage the surface of the steel wire;

⑤ When armored with steel wire, the beginning and end of the cable core must have traction wires with the same outer diameter to ensure that the wire is always armored under tension, and no internal stress is generated at the beginning and end of the wire. At the same time, the beginning and end of the steel wire must be tied firmly to prevent the occurrence of steel wire slippage;

⑥ After the steel wire armor is wrapped, it is usually necessary to use double-layer non-woven fabric to overlap and wrap it tightly, because the elasticity of the steel wire is very high. After winding the wire reel, under the bending effect, it is easy to stretch the outer layer of the tie, or the friction between the layers or between the layers of the wire core after wrapping can easily tear the tie. If these cannot be handled properly, it will bring great trouble to the subsequent extrusion process.

In addition, manufacturers of cage type stranded wire equipment recommend using cage type stranded wire equipment for steel wire armor. This way, as the cage type stranded wire machine can untwist the armored steel wire, the internal stress inside the steel wire will be greatly reduced, and the phenomenon of lantern lifting will not occur. In addition, the tension of each pay off reel on the outer cage type stranded wire equipment is easy to adjust and very uniform, so there will be no jumper or back strand phenomenon during armor, which can greatly improve production efficiency and product quality.

3. Extrusion process of sheath:

When extruding the outer sheath, the starting end of the cable is rotated several times in the direction of the steel wire according to the pitch of the steel wire and the length of the cable, and then connected to the traction wire. A steel rod is used to lock it at the traction connection to prevent the cable from loosening due to the rotation under the stress of the steel wire, which may cause the steel wire to play a lantern during the extrusion process. This rod can be removed after the wire is pulled and retracted.

In summary, manufacturers of steel wire armored cables can prevent or reduce the occurrence of steel wire lantern phenomenon by paying attention to the three processes of cable formation, steel wire armor, and outer sheath extrusion.