I. Scope of Application
Repairs are permitted for local defects in the PVC insulation and sheath of wires and cables, such as broken adhesive, collapsed pits, disconnected joints, wrinkles, bumps, ears, ridges, punctures, and splices.
II. Materials and Equipment
The raw materials should be plastic strips, sheets, blocks, or tubes of the same plastic material. The raw materials should be smooth, clean, and free of other defects.
The equipment used is a fine wood rasp, knife, scissors, pliers, screwdriver, copper sheet, or smooth cable paper. For plastic welding, use a hot air welding gun or electric soldering iron with a power of 300W or higher.
III. Repair Methods for Local Defects
1. Repair Methods for Penetration Points, Holes, and Collapses
Use a knife to trim the defect and cut a uniformly sized plastic block with a 45° slope. Place it on the repair area and secure it with pliers or a screwdriver. Then, use a hot air welding gun to continuously weld the plastic. Use a copper sheet to compact, press, and flatten the plastic. When welding plastic, be careful not to overheat the hot air from the welding torch to prevent the plastic at the repair site from burning. After repairing, the defect must pass the spark test. If no penetration is detected, the defect is considered acceptable.
2. Repair Methods for Glue Breaks, Cracks, Depressions, and Cuts
Use a knife to cut a 45° bevel at the defect site in the plastic layer. Remove plastic blocks or strips of consistent shape, color, and thickness. Secure them with pliers or a screwdriver, then connect them using a hot air welding torch. Then, use a copper sheet to compact, press, and flatten the defect. Finally, test the repaired defect with a spark test. If no penetration is detected, the defect is considered acceptable.
3. Repair Methods for Ears, Bumps, Ridges, and Wrinkles
Use a knife to flatten the defect. Use a plastic strip of the same material to fill the defect with the hot air welding torch. Then, use a copper sheet to flatten, press, and flatten the defect. Test the repaired defect with a spark test. If no penetration is detected, the defect is considered acceptable.
4. Repair Methods for Large Joints
1) Repairing General Large Joints: Use a knife to cut a 45° bevel along the circumference of the plastic layer on both sides of the broken rubber. Take a clean plastic tube of uniform color and thickness, and of the same length and outer diameter as the broken rubber. Cut two openings along the axis of the tube at 45° angles to each other and place them over the broken rubber. Tie them with fine copper wire at equal intervals. Then, weld the joints using a hot air welding torch with the same plastic strips. Then, compact, press, and flatten them with copper sheets. The joints are considered acceptable if they do not show any punctures when tested with a spark machine.
2) Repairing Large Joints During Production: If the sheath is disconnected during production due to other reasons, a continuous joint can be made. The method is to cut the plastic sheath into a 45° bevel, retract it to the machine head, and insert it into the core nozzle for 30mm. Then, run the glue. After the glue is run, the crew coordinates and manually connects the plastic layers while the machine is running, then reshape and repair the joints. 3) If the cable sheath is defective along a long distance from one end, while the other end is mostly intact, and the cable length is fixed, the method for repairing the large joint during production can also be used. Simply remove the defective sheath from the end, equip the extruder with a larger die, and extrude the sheath on the removed end according to the process. Gradually increase the pulling speed to the large joint, gradually thinning the sheath at the interface and wrapping it over the original sheath cut into a sloped shape. After removing the cable from the machine, reshape and repair the cable.
