Visual inspection. For the inspector, it is not an easy task. The scale of the main visual inspection is not well mastered. If the same product is inspected by different inspectors, different conclusions may be obtained. In spite of this, as long as we carefully study and master the standards and accumulate experience, we can use the standard samples to check if necessary, and we can do a good job of visual inspection of the products.
1. Round aluminum rods are required to check the degree of rounding, whether there are defects such as hemming, rounding, cracks, inclusions, kinks and serious mechanical damage, pits, skins, flashing, corrosion spots, etc.
2, round copper wire to check whether the surface is smooth, with or without triangular mouth, burrs, cracks, folding and inclusions and serious spots, pits, corrosion spots of mechanical damage. It is worth mentioning that there is also the degree of oxidation of copper wire. Generally, golden yellow is normal, light red is slightly oxidized, and the surface is dark red and blue is severely oxidized. Any serious oxidation should be judged as waste disposal. There are many roads in the manufacturing process of aluminum wire, and should be strictly controlled when making overhead transmission lines.
3, aluminum wire surface, the wire should be twisted tightly and tightly, can not be loose, single-line kink, single-line jump or bump and single-line fracture phenomenon. In addition, the joint welding of the single wire should be rounded and the welding is required to be treated with anti-corrosion treatment. The enlarged part of the joint is generally not allowed to exceed twice the diameter tolerance. The length of the two welded joints of the single-wire joint is also in accordance with the standard. The welding place shall be not less than 15 meters. The inner layer of the same layer shall be not less than 5 meters, and the outer layer shall be not less than 5 meters. The outer layer shall not be less than 15 meters. When the copper core is a single copper wire, welding shall not be allowed. 4 Appearance and structural dimensions of the cable The appearance and structural dimensions of the cable are generally interspersed or carried out at the same time. The quality of the product is good or bad. On the one hand, its performance is excellent, but the quality of its appearance and structural dimensions also accounts for a certain proportion. The appearance and structural dimensions of the product have an impact on the performance of the cable.
(1), local thinning, causing local heating, increased resistance, accelerated insulation aging.
(2), rust spots, affect the conductor joints, increase the resistance, insulation is easy to age.
(3), bruises or scratches affect the mechanical strength of the conductor.
The visual inspection of the cable is to check the surface condition of the finished product, semi-finished product or material. The dimensional inspection is to evaluate each product according to the size of each part specified in the product standard. The structural inspection of the cable refers to the inspection of the structure of the various components of the cable. The appearance inspection, such as the oxidation of the copper wire, has an impact on the quality of the cable. The size can directly affect the performance of the product, such as the outer diameter of the conductor and its resistance. Related; insulation thickness and resistance are related to the degree of withstand voltage; the pitch of the strand is related to the softness and firmness of the product. Structural inspection can expose the manufacturing quality of the cable and find problems in the production process. Therefore, controlling the appearance and structural size is the guarantee of product performance.