1. Non compliant crosslinking degree (thermal elongation)

If the cross-linking degree does not meet the standard, the thermal mechanical properties of the cable are not qualified and cannot meet the requirement of a working temperature of 90 ℃.

The reason for the unqualified cross-linking degree is twofold: firstly, the formula is unqualified, and the type and proportion of the compounding agent are improper. The formula should be adjusted to solve this problem; The second issue is improper sulfurization process, such as low air pressure, fast line speed, high cooling water level, etc. The solution is to first identify the cause, which may be one or several reasons at the same time, and eliminate the root cause.

2. Unqualified structure and appearance

（1） The thinnest point of the insulation layer thickness is lower than the minimum value specified by the standard, or the average thickness is lower than the nominal value. The reasons for the unqualified insulation thickness are fast line speed, small extrusion glue output of the extruder, and improper mold selection.

The solution is to reduce the line speed or increase the extruder speed, and adjust the size of the mold.

（2） Eccentricity

The reason for eccentricity is that the mold has not been adjusted or the suspension control has changed after the recruitment and adjustment. The solution is to try to stabilize the suspension control as much as possible during the driving process.

3. Bamboo like structure

The reason for the bamboo like appearance of the cable is due to electrical and mechanical systems causing unstable traction speed, as well as small mold cores or uneven outer diameters of the conductors.

The troubleshooting method is to check the mechanical and electrical systems and eliminate faults. Adjust the size of the core appropriately, control the outer diameter of suburban areas as evenly as possible, and use stranded wires that exceed the process specifications.

4. Surface scratches

（1） The cable encounters the upper and lower walls or foreign objects in the vulcanized pipe. So it is required to adjust the suspension degree well, try to make the wire core move in the middle of the cross-linked tube, and promptly clean up any foreign objects found.

（2） The outer edge of the mold sleeve is scorched. The solution is to adjust the temperature of the mold sleeve when starting the car to prevent overheating. Once burnt, it should be immediately stopped and cleaned, or it may not improve on its own.

5. Impurities

Most impurities in insulating and semi insulating materials are introduced during mixing and during the feeding process of the extruder. During the operation, strict attention should be paid to the cleanliness of the materials to prevent external impurities from entering. Another type of impurity is burnt lumps, which affect the performance and service life of the cable. Therefore, the temperature should be strictly controlled during mixing and extrusion to prevent burnt phenomena from occurring.

6. Bubble

There may be two reasons for the bubbles generated in insulation. One is caused during extrusion molding. The solution is to select appropriate molds. There are bubbles in the shielding layer, mainly due to the presence of moisture in the material, which should be dried before extrusion. Secondly, insufficient cooling can cause a circle of bubbles to appear on the circumference equidistant from the wire core. The elimination method is to strengthen cooling, raise the water level, and lower the temperature of the cooling water.