The main problems of defective and scrap wire bundles and stranded wires include excessive twisting, breakage of inner or outer single wires, lack of strands, surface scratches on single wires or stranded wires, single wire back strands, peeling, scars, brittle fractures, arches, inclusions, wire diameter deviation or mixing errors, twisted direction error, snake shape, large twisted pitch, unqualified length, loose strands, disordered and pressed wires, scratches, collisions, and unqualified DC resistance of wire and cable conductor cores.
　
1. Overtorsion
　
Over twisting refers to the phenomenon of excessive twisting in Fried Dough Twists shape during stranding.
　
Reason for occurrence: Firstly, the number of turns of the stranded wire on the traction wheel is not enough, usually less than 4 turns. The friction force is too small and the wire slips, resulting in excessive twisting. The second is that the tension of the take-up wire is loose or the take-up reel does not rotate, while the rotating body is still rotating, resulting in excessive twisting.
　
Exclusion method: If the outer single line has undergone severe deformation and damage, there is no possibility of repair, only cutting. If the single wire is not severely damaged, the rotating part and the traction part of the equipment can be separated, and it can be turned in the opposite direction of the twisting to retract the partially twisted part. Then, the wire core can be repaired by hand, and the excess single wire can be wound onto the take-up reel. The equipment and rotating part can be pulled together, and the loose part can be pressed onto the wire mold with force, and the mold can be manually repaired to restart production.
　
2. The cause of single wire breakage during stranding is:
　
l) Due to excessive wire tension, the wire core is pulled and broken.
2) During the drawing process, the single wire is loose, poorly arranged, and the wire is pressed across the wire, causing the wire core to break.
3) The material of the single wire itself has cracks, and its mechanical properties are poor and brittle.
4) The installation position of the pay-off reel is incorrect, causing axial shaking and causing wire breakage.
5) Single wire jumps out of the pulley groove, causing mechanical jamming.
　
Troubleshooting method: ① Adjust the tension of the wire to make it appropriate. ② Pay attention to selecting the incoming line. If there is any looseness during the pulling process, it must be rewound before starting the machine Pay attention to the operation method and carefully check the position of the wire reel to ensure that the released wire does not swing or jump. Check whether there is any phenomenon of jumping out of the guide groove where a single wire passes through. ④ To check the surface quality of the wire core, check for defects such as cracks, slag inclusions, and scars. If the wire break occurs in the inner layer and the broken end has been run too long, it cannot be repaired. Only cut off the missing strand core. If the wire break occurs in the outer layer, the wire should be repaired before starting the machine.
　
3. Scratches on the surface of the stranded wire, scratches on the wire core
　
Causes: Usually, one is due to the wear of the wire nozzle on the wire reel, the other is due to the single wire jumping out of the pulley, the third is due to the use of wooden or plastic pipes for threading, the fourth is due to the damage of the positioning pin on the traction equipment push line board, and the fifth is due to foreign objects in the mold.
　
Solution: Replace the threading nozzle on the distribution board and the wooden and plastic pipes used for threading, check whether the direction of the wire core is normal, protect the wire core from direct wear and tear with the equipment, and check the integrity of the pressing mold at any time, and pay attention to the operation method.
　
4. Single back strand and loose strand in bundle and stranded wire
　
Causes: Firstly, the tension of the wire is uneven, loose and tight, with too many loose wire cores leading to back strands. Secondly, the mold hole is too large to properly adjust the tension. Thirdly, the mold position is improper, the twist angle is unreasonable, and fourthly, the pitch is relatively large.
　
The bundle machine is used to bundle single wire cores with 19 or more strands. Due to the fact that there is no difference in direction between the bundles, they can only be bundled in the same direction, resulting in an irregular combination of wire cores. Currently, most manufacturers use a double pitch bundle system. Therefore, the phenomenon of back and loose strands of wire cores with 19 or more strands is more serious than that of stranded wires.
　
Exclusion method: For bundle products (with more than 1 strand), the first step is to improve the wiring device of the bundle, using more advanced single wire tension payout devices, so that the tension of each single wire can be adjusted and controlled. The second is to use a guiding die, with the aperture of the guiding die being 97% of the calculated outer diameter of the beam line. This way, the guide mold can adjust the tension appropriately. The third is to switch to a single pitch bunching machine, which can produce bunching products that meet the level of stranded wire. The fourth is to use the method of overmolding and rewinding to repair the wire cores with severe looseness and back strands, which can also meet the requirements of use. Fifth, adjust the pitch ratio appropriately.
　
For stranded wire products, the elimination method for loose strands is to adjust the pay-off tension to make it even. The second is to replace the mold, so that the wire core is not loose in the mold hole, and pay attention to the bell mouth of the mold. If the bell mouth is already damaged, it cannot be used. The third is to adjust the position of the die holder to make the twist angle of the stranded wire reasonable. Fourthly, if the twist pitch is large, it should be appropriately reduced.
　
5. Single wire slot or surface defect in stranded wire
　
Reason for occurrence: Defects such as pits, scars, triangular cracks, and slag inclusions on the surface of the single wire are mainly caused by the material. Of course, there are cracks on the surface of the wire core, which cannot be ruled out due to the unreasonable hole type of the wire drawing die. In this case, a specific analysis is required. The groove on the surface of the wire core is continuous, usually caused by pulling wire. The lubrication condition of the pulling wire deteriorates, and the surface is coated with aluminum. The groove that is not continuous may be caused by foreign objects sticking to the wire compression mold.
　
Elimination method: For aluminum wire slotting during pulling, the lubrication effect of the pulling wire should be checked first to ensure that it meets the requirements of the pulling wire. It is necessary to replace the lubricating oil and the pulling wire mold in a timely manner, or remove any debris adhering to the wire mold. The incoming wire should be carefully inspected, and unqualified incoming wires should be promptly eliminated. At the same time, the pressing wire mold should be checked for damage and debris, and repaired and replaced in a timely manner.
　
6. The diameter of a single line may vary greatly, slightly, or with the wrong core
　
Cause: During stranding, it was found that the diameter of the single wire exceeded the tolerance or the wrong core was mixed. The main reason was that the process regulations were not carefully implemented, and another reason was that there were certain management issues.
　
Elimination method: If the length of the mixed wire core is not long, it can be removed, replaced, and repaired according to the wiring repair method. If the length is too long, it cannot be repaired. Only remove the machine and handle it separately. Therefore, before starting the machine, the operator should carefully inspect and measure. Of course, managers should also provide a guarantee method, such as whether there are too many wire gauges, whether the tolerances are reasonable, whether the production scheduling is arranged properly, and carefully consider the problems in management according to the PDCA principle to avoid the generation of artificial defective and scrap products.
　
7. Stranded wire core loose strand
　
Reason for occurrence: (l) Excessive pitch, resulting in unstable stranded wire cores. (2) The mold hole is too large to have a compaction and adjustment effect. The bell mouth of the wire mold is too large or worn or damaged. (3) The tension of the pay-off wire is uneven, loose and tight. (4) The pitch ratio of each layer is not well matched. (5) The state of the wire core does not comply with the process regulations, especially the aluminum wire core. (6) Improper position of the wire splitter and die holder, etc.
　
Exclusion method: Firstly, strictly follow the process discipline, follow the process operation procedures, appropriately reduce excessive pitch, adjust the tension of the wire and the mold. The position of the wire splitter to the mold base is generally adjusted to 200-250mm according to different structures. For twisted wires with particularly high tensile strength, the method of combining molds can be used, which also has good results. Of course, it is important for operators to operate according to the methods specified in the process operation regulations.
　
8. Twisting direction is incorrect, and the twisting pitch is not qualified (mainly due to being too large)
　
Reason for occurrence: Wrong direction mainly refers to incorrect judgment. Operators should strengthen their sense of responsibility during operation, strictly follow the process card, and strengthen flow inspection to prevent the generation of artificial defective and scrap products.
　
9. Disordered wiring and crimping
　
Reason for occurrence: Stranded products are generally supplied in coils. Large cross-section, should be arranged one by one, especially the bottom line should be neatly arranged. When turning the line around, due to a pause, special attention should be paid to not leaving too much gap between the upper and lower layers, and the row spacing should be appropriate, as excessive spacing can easily cause line compression.
　
Solution: Firstly, adjust the tension of the take-up wire. When manually arranging the wires, it is advisable to arrange them flexibly. Secondly, change the pitch of the wire according to the diameter of the wire core. Arranging the first layer is crucial and must be arranged neatly; Arrange for the second layer. During layer adjustment, manual wiring should be carried out to ensure the quality of the wiring. The third is to strengthen the sense of operational responsibility and observe the quality of the wiring at any time. If problems are found, they should be adjusted in a timely manner, and attention should be paid to fixing the two wire ends and keeping the distance between the edges.