1. Overtorsion
Over-twisting refers to the phenomenon of excessive twisting in the twisting process.
Causes: First, the number of turns of the twisted wire on the traction wheel is not enough, generally less than 4 turns, the friction is too small and slips, resulting in excessive twisting. The second is that the take-up tension is loose or the take-up reel does not rotate, while the swivel is still rotating, resulting in excessive twisting.
Remedy: If the outer single wire has been severely deformed, the damage is serious, and there is no possibility of repair, only shearing. If the single wire is not seriously damaged, separate the swivel part and the pulling part of the equipment, turn it in the opposite direction of the twist, so that the partially twisted part is retracted, then repair the core by hand, and rewind the excess single wire to the On the take-up reel, combine the equipment and the swivel traction. After the loose over-pressing wire die, press the wire hard, and use another die to manually repair it, so that the production can be restarted.
2. Reasons for disconnection and lack of strands during stranding
1) The wire core is broken due to excessive pay-off tension.
2) When the single wire is drawn, the wire is loose, the wire is not well arranged, and the wire is pressed across the wire, causing the wire core to break.
3) There are cracks in the material of the single wire itself, and the mechanical properties are not good and brittle.
4) The installation position of the pay-off reel is improper, and the shaft is shaken, resulting in disconnection.
5) The single line jumps out of the pulley groove and is mechanically stuck.
Remedy: ① Adjust the pay-off tension to make it appropriate. ② Pay attention to the selection of the incoming wire, and find that there is a loose phenomenon when pulling the wire, and it must be rewound before it can be used on the machine. ③ Pay attention to the operation method, carefully check the position of the pay-off reel, so that the paid-out line does not swing or jump, and check the place where the single line passes, whether there is any phenomenon of jumping out of the guide wheel groove. ④ Check the surface quality of the wire core to see if there are cracks, slag inclusions, scars and other defects. If the broken wire occurs in the inner layer, and the broken end has gone too long, it cannot be repaired. Only by cutting off the missing strand core, if the broken wire occurs in the outer layer, the wire should be repaired before starting the machine.
3. The surface of the stranded wire is scratched and the core is scratched
Causes: Usually, the first is the wear of the thread nozzle on the distribution plate, the second is that the single line jumps out of the pulley, the third is that the wooden pipe or plastic pipe is used for threading, the fourth is that the positioning pin on the pusher board of the traction equipment is damaged, and the fifth is that the pressing mold is in the middle. There are foreign bodies and other reasons.
Elimination method: replace the threading nozzle on the distribution plate 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 with the equipment, and check whether the die is in good condition at any time, and pay attention to the operation method. .
4. Single wire back strands and loose strands in bundled wires and stranded wires
Causes: First, the tension of the pay-off is uneven, the looseness is tight, and the loose wire core travels too much, causing back strands. Second, the hole shape of the die is too large, and the tension cannot be adjusted properly. The third is the die. Improper position, unreasonable twist angle, and fourthly, the pitch is relatively large.
The harnessing machine bundles single cores with 19 strands or more. Since there is no difference in the direction of the harnesses, they can only be bundled in the same direction, so the combination of the cores is irregular. At present, most manufacturers use the double-pitch bundle system. The wire harness has more than 19 strands, and the back strands and loose strands are more serious than stranded wires.
Elimination method: For the bundled wire (bundle products with more than one strand), the first is to improve the pay-off device of the bundled wire, and use the more advanced single-wire tension pay-off device, so that the tension of each single wire can be adjusted and controlled. The second is to use a guide die, and the aperture of the guide die is 97 percent of the calculated outer diameter of the beam line. In this way, the guide die can properly adjust the tension. The third is to switch to a single-pitch wire harnessing machine, which can reach the level of stranding. Fourth, for the back strands and the seriously loose strands, the wire cores can be repaired by over-mold rewinding, which can also meet the requirements of use. Fifth, adjust the pitch ratio appropriately.
For the back strands of stranded wire products, the elimination method of loose strands: First, adjust the pay-off tension to make it uniform. The second is to change the die, so that the wire core should not be loose in the die hole, pay attention to the bell mouth of the die, if the bell mouth is damaged, it cannot be used. The third is to adjust the position of the die holder to make the twisting angle of the strand reasonable. Fourth, if the stranding pitch is large, it should be appropriately reduced.
5. Single wire grooves or surface defects in stranded wires
Causes: 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, the surface of the wire core is broken, and it is not excluded that the hole type of the wire drawing die is unreasonable. A case-by-case analysis is required. The groove on the surface of the wire core is continuous, which is generally caused by the wire drawing. The lubricating conditions of the wire are deteriorated, and the surface is caused by sticking to aluminum.
Elimination method: For the grooved aluminum wire when pulling the wire, you should first check whether the lubricating effect of the wire can meet the requirements of the wire. It is necessary to replace the lubricating oil in time, replace the wire drawing die, or remove the sundries stuck on the wire die, and carefully check the incoming wire. Unqualified incoming wires should be eliminated in time, and at the same time, check whether the wire pressing die is damaged or not, and whether there is any debris, and repair and replace it in time.
6. The diameter of the single wire is suddenly large, suddenly small or mixed with the wrong wire core
Cause: It is found that the single wire diameter is out of tolerance or the wrong core is added during the stranding. The main reason is that the process regulations are not carefully implemented, and the other reason is that there are certain problems in management.
Elimination method: If the length of the wrong wire core is not long, you can remove it, change the wire again, and repair it according to the braided wire repair method. If the length is too long, it cannot be repaired, only off the machine and deal with it separately. Therefore, before starting the machine, the operator should carefully check and measure. Of course, the manager should also provide a guarantee method, such as whether the wire gauge is too large, whether the tolerance is reasonable, whether the production scheduling is properly arranged, and carefully consider the existing problems in management according to the PDCA principle, so as to avoid the production of artificial defective products and waste products.
7. Stranded core loose strands
Causes:
(l) The pitch is too large, causing the stranded core to not be solid.
(2) The hole type of the die is too large to achieve compaction and adjustment. The wire die bell mouth is too large or worn and damaged.
(3) The tension of the pay-off is uneven and loose.
(4) The pitch ratio of each layer is not well matched.
(5) The state of the wire core does not meet the process regulations, especially the aluminum wire core.
(6) The position of the splitter and the die seat is improper, etc.
Elimination method: First of all, strict process discipline, implement process operation rules, appropriately reduce excessive pitch, and adjust pay-off tension and die. The position from the splitter to the die holder is generally adjusted to 200250mm according to different structures. For twisting some strands with particularly high tensile strength, the method of combining molds can be used, which also has good results. Of course, it is very important for the operator to operate according to the methods specified in the process operation regulations.
8. The stranding direction is wrong, and the stranding pitch is unqualified
The reason is that the wrong direction is mainly a judgment error. When operating, the operator should strengthen the sense of responsibility, strictly follow the process card, and should strengthen the flow inspection to prevent the production of artificial defective products and waste products.
9. The wiring is chaotic and pressing
Reason: Stranded products are generally supplied in trays. Large cross-sections should be arranged one by one, especially the bottom line should be arranged neatly. When the cable is turned around, because there is a stop, special attention should be paid, there should not be too much gap between the upper and lower layers, and the row spacing should be Appropriate, too large is easy to cause pressure line.
Elimination method: First, adjust the tension of the take-up wire. When manually arranging the wire, it is appropriate to arrange it in a moving manner. Second, change the wire arrangement pitch according to the diameter of the wire core. Arranging the first layer is the key, and it must be arranged neatly. ; Arrange the second layer, when adjusting the layer, it is necessary to manually arrange the cable to ensure the quality of the cable. The third is to strengthen the sense of operational responsibility to observe the quality of the cable at any time, and to adjust it in time if any problems are found.
