1.The degree of cross-linking (hot elongation) is unqualified
If the degree of cross-linking fails to meet the standard, the thermal-mechanical properties of the cable are unqualified and cannot meet the requirements of the working temperature of 90 ° C.
The reasons for the unsatisfactory cross-linking degree are: first, the formula is unqualified, and the type of the compounding agent is improper, and the formula should be adjusted to solve it; second, the vulcanization process is caused by factors such as too low air pressure, fast line speed, and high cooling water level. The solution is to first find out what the cause is, it may be one or more reasons may exist at the same time, and the reasons shall be eliminated.
2, the structure and appearance are unqualified
(1) The thinnest point of the thickness of the insulation layer is lower than the minimum value specified by the standard, or the average thickness is lower than the nominal value. The reasons for the unsatisfactory insulation thickness are the fast line speed, the small amount of glue produced by the extruder, and the improper selection of the mold.
The solution is to reduce the line speed or extruder speed and adjust the size of the mold.
The reason for eccentricity is that the suspension degree control has changed after the mold is not adjusted or the adjustment is adjusted. The solution is to try to stabilize the sag degree during the driving process.
竹 The reason for the bamboo-like shape of the cable is that the traction speed is unstable due to electrical and mechanical systems. The second reason is that the core is too small or the outer diameter of the conductor is uneven.
The troubleshooting method is to check the mechanical and electrical systems and remove the fault. Properly adjust the size of the core to control the outer diameter of the suburb as much as possible, and the stranded wire that exceeds the process requirements can be used.
4, scratched surface
(1) The cable hits the top, bottom or foreign body in the vulcanization tube. Therefore, it is required to adjust the degree of suspension, try to make the core move in the middle of the cross-linked pipe, find foreign objects, and clean up in time.
(2) There is scorch on the outer edge of the mold sleeve. The solution is to adjust the temperature of the mold sleeve when starting the vehicle to prevent overheating. Once scorching is found, it should be stopped immediately to clear it, or it will not become better by itself.
杂质 Most of the impurities in the insulation material and semi-insulation material are brought in during the mixing and the extruder feeding process. During the operation, strict attention should be paid to the cleanliness of the materials to prevent foreign impurities from being mixed in. The other kind of impurities is scorch, its presence affects the performance and service life of the cable, so strictly control the temperature during mixing and extrusion to prevent scorch.
There are two possible reasons for air bubbles in insulation. One is caused during extrusion. The solution is to choose the right mold. The shielding layer has air bubbles, the main reason is that there is moisture in the material, it should be dry before extrusion, and the second is insufficient cooling. At this time, the following will appear, a circle of air bubbles will appear on the circumference of the equidistant circumference from the core. The method of elimination is to strengthen the cooling, raise the water level and reduce the temperature of the cooling water.