Product quality, the first characteristic is reflected in the appearance of the product quality, no matter what kind of products, or semi-finished products, in production must pay attention to the appearance of quality, strict control and inspection.

Sheath is the appearance of the cable, the appearance of the requirements of smooth round, uniform luster, no core deviation (shall not exceed the specified deviation), no mechanical damage, flat, no visible sundry, bubble, trachoma, obvious particles, bamboo, distortion, etc.. In addition to meeting the above quality requirements, sheath thickness also has a certain impact on cable quality.

As is known to all, the role of cable sheath is to protect the cable insulation core from damage under the action of external forces, playing a protective role. If the thinnest point of the cable sheath does not meet the requirements, the cable sheath will be damaged before reaching the maximum normal damage.

If the thickness of cable sheath in production is lower than the standard requirement, it is unqualified, and if the thickness exceeds the standard requirement, it is unqualified. If the cable model is DLD -kyjv22 3*1.5mm2, the average thickness of the sheath is measured as 1.7mm. The thickness of the model is 1.2mm, in line with gb9330-88 standard.