With the fierce market competition, the continuous development of the wire and cable industry, and the continuous improvement of users' awareness of the quality of cable products. The user's demand for cable products is not only the price and cost of a single product, but also pays more attention to the internal and external quality of the product. The required products not only require their internal performance to meet the corresponding production technology standards (GB, JB, MT...), but also pay special attention to the appearance quality of the product, such as the appearance of the product 　　

There should be no undesirable phenomena such as convex hulls, pits, coke seeds, cold lumps, rough drawing, and no pores in the profile. The occurrence of these undesirable situations will cause users to be dissatisfied with the batch of cables, raise doubts about the quality of the company's products, and often cause user complaints or affect the corporate image and impact on the corporate market. In this article, the author combines the experience and experience of dealing with the damage of the outer sheath of the non-armoured large cross-section single-core cable

Its experience in production practice puts forward a superficial view on the quality problems, cause analysis and quality control of non-armoured large cross-section single-core cables in the production process.　　

Characteristics and process characteristics of large cross-section single-core cables　

Due to its own characteristics, large cross-section single-core cables have large cross-sections, heavy metal materials, and relatively thin extruded sheaths.　

When extruding the sheath of large cross-section copper core single-core cables, the 150 extruder is generally used to extrude the sheath. The production process is roughly as follows: insulation extrusion (including conductor shielding, insulation, and outer shielding)-copper tape shielding ——Extrusion of the sheath.

From the structure size table and extrusion production process of large cross-section single-core copper core cross-linked cable, it can be seen that the surface of the sheath needs to be cooled after the sheath is extruded. If the sheath is not cooled in place, the cable is likely to cause surface wrinkles and breakage. Abnormal quality such as deformation of the surface of the cable sheath at the mouth and the bottom of the plate.

From the perspective of the cable cooling and heat dissipation balance principle (Q put = Q suction = Q copper + Q water + Q it) and the actual production, in general, even at the same production speed and the same cooling conditions, the extrusion outer diameter is almost the same The armored type has better heat dissipation than the non-armored type, and its cooling effect is relatively better.

Cause analysis of product quality defects and process control measures

In the process of producing large cross-section single-core cables, the main external quality defects are manifested as sheath wrinkles, holes, tears, coke seeds, cold material lumps, wire drawing roughness, multiple steam holes in the section, and cable sheath at the bottom of the disk. The surface is deformed, the sheath is naturally inflated and loosened after the head, and the sheath is scratched on the side of the cable reel.

In addition, during the extrusion process, due to its own drop, even if it is aligned with the eccentricity, the phenomenon of thick upper part and thin lower part is often due to date. At the same time, because of the heat dissipation of copper strip compared with steel strip, its cooling effect is at the same extrusion speed. Downstream is slower than armored cables. If the cooling water tank is not fully utilized when the product is extruded, there will often be a gap between the product and the wire reel after the product passes through the spark machine. The appearance of the product generally does not appear to be abnormal.

Problem, but because the selected reels are not all flat after receiving the reel, and the randomness of the wiring, sometimes the cables on both sides of the reel will rub against the side reel of the reel, and in the inner layer of the bottom of the reel Cables will twist. If the surface of the cable sheath is not cooled enough, the cable sheath will wrinkle. In severe cases, the cables will be scratched due to twisting.

For the quality of large cross-section single-core cables. The author believes that regardless of production and use, manufacturers, distributors and users must have an understanding of cable characteristics and basic knowledge of laying. Especially cable manufacturers need to strengthen cause analysis and control from the product quality process, and continue to summarize production. The purpose is to analyze the abnormal phenomena that occur in the process and make control measures to reduce product quality defects and improve the internal and external quality of the product.