Quality defects of cable bundle wire and stranded wire
Regarding the causes and elimination methods of the defects of the cable harness and stranded wire:
Causes
1. 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.
2. The tension of the take-up wire is loose or the take-up reel does not rotate, and the rotor is still rotating, resulting in excessive twisting. To
elimination method
If the outer single wire has been severely deformed and the damage is serious, there is no possibility but cut. If the single wire is not severely damaged, you can separate the rotating part of the equipment from the traction part, turn it in the opposite direction of the twisting, and return the partially twisted part, then repair the core by hand, and wind the excess single wire to On the take-up reel, unite the equipment and the swivel traction. After the loose over-pressure line mold, press the line forcefully and manually use the mold to restart the production.
Single wire breaks during twisting and its causes:
1. The wire core is broken due to excessive pay-off tension.
2. When the single wire is drawn, it is loose and disorderly, the wiring is not good, and the crimping wire crosses the wire, causing the wire core to break. To
3. The material of the single wire itself has cracks, and the mechanical properties are not good and brittle.
4. Improper installation position of the pay-off reel, causing axial shaking, causing wire breakage.
5. The single wire jumps out of the pulley groove and the mechanical jam is broken. To
elimination method:
1. Adjust the pay-off tension to make it appropriate.
2. Pay attention to the selection of the incoming line. It is found that there is looseness when pulling the line, and it must be rewinded before getting on the machine. To
3. Pay attention to the method, carefully check the position of the pay-off reel to ensure that the discharged line does not swing or jump, and check the place where the single line passes, whether it jumps out of the guide wheel groove.
4. Check the surface quality of the core to see if there are defects such as cracks, slag inclusions, and scars. If the disconnection occurs in the inner layer, and the broken end has gone too long, it cannot be repaired. Only cut off the missing strand core. If the disconnection occurs in the outer layer, the thread should be turned on again.
cause:
1. The thread nozzle on the splitter is worn out
2. Single wire jumps out of the pulley
3. Use wooden or plastic pipe for threading
4. The positioning pin on the push board of the traction equipment is damaged
5. There are foreign objects in the mold.
Elimination method: Replace the threading nozzle on the spool and the wooden tube and plastic tube used for threading, check whether the direction of the core is normal, protect the core from direct wear to the equipment, and check whether the die is intact at any time, and pay attention to the method.
Causes: 1. The pay-off tension is uneven, the tension is tight, and the tension of the core goes too much, causing back strands. 2. The die hole is too large to properly adjust the tension. 3. Improper position of die, unreasonable twist angle, fourth, relatively large pitch, etc. The single wire cores of 19 strands and above are bundled by the wire harness machine. Because there is no difference in the direction of the wire harness, it can only be bundled in the same direction, so the wire core combination is irregular. At present, most manufacturers use the double pitch bundle system. Wire cores with more than 19 strands in the wire harness system have more back strands and loose strands than twisted wires.
elimination method:
For bundle wire (bundle products with more than 1 strand)
1. Improve the pay-off device of the beam line, adopt a more advanced single-line tension pay-off device, so that the tension of each single line can be adjusted and controlled.
2. Using a guide die, the aperture of the guide die is 97%% of the calculated outer diameter of the beam line. In this way, the tension of the guide die can be adjusted appropriately.
3. Switch to single-pitch wire harnessing machine, which can reach the level of twisting wire.
4. For back strands and severely loose strands, the use of over-mold rewinding can also meet the requirements of use. Fifth, adjust the pitch ratio appropriately.
For stranded wire products
1. Adjust the pay-off tension to make it even.
2. Change the pressure mold, so that the core is not loose in the mold hole, pay attention to the bell mouth of the pressure mold, if the bell mouth is damaged, it cannot be used.
3. Adjust the position of the die seat to make the twisting angle of the stranded wire reasonable.
4. If the stranding pitch is large, it should be appropriately reduced.
5. Grooves or surface defects in single wires in stranded wires
Causes: defects such as pits, scars, triangle 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 chipped, and the unreasonable hole pattern of the drawing die cannot be ruled out. It needs to be analyzed in detail. The continuity of grooves on the surface of the core is generally caused by the wire drawing. The lubrication condition of the drawing wire is deteriorated and the surface is sticked to aluminum. The non-continuous grooving may be caused by foreign matter sticking to the stranding die.
Remedy: For aluminum wire grooves during drawing, first check whether the lubrication of the drawing wire can meet the requirements of the drawing wire. It is necessary to replace the lubricating oil in time, replace the drawing mold, or remove the debris on the wire mold, carefully check the incoming wire, right? Qualified incoming wires should be eliminated in time, and at the same time, check the crimping die for damage and debris, and timely repair and replacement.
Cause: The single wire diameter is found to be out of tolerance or the wrong core is found in the stranding. The main reason is that the process regulations are not carefully implemented. Another reason is that there are certain problems in management. To
Elimination method: If the length of the wrong core is not long, you can remove it, change the thread again, and repair it according to the braiding method. If the length is too long, it can't be repaired, only get off the machine and deal with it separately. Therefore, the author should carefully check and measure before getting on the machine. Of course, the manager should also provide a guarantee, such as whether the wire gauge is too large, the tolerance is reasonable, whether the production scheduling is properly arranged, according to the PDCA principle, carefully consider the management problems, and avoid the production of artificial defective products and waste products.
Causes:
1. The pitch is too large, causing the stranded wire core to be unstable.
2. The die hole is too large to achieve compaction and adjustment. The mouth of the wire mold is too large or worn or damaged.
3. Uneven pay-off tension, loose and tight. To
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. Improper position of the splitter and die holder, etc.
Elimination method: Firstly, strictly process disciplines, implement process rules, appropriately reduce excessive pitch, and adjust the pay-off tension and die. The position of the line splitter to the die seat is generally adjusted to 200~250mm according to different structures. For stranding some strands with particularly high tensile strength, the method of combining molds can be used, and there are also better methods.
cause:
1. Wrong stranding direction, unqualified stranding pitch, wrong direction is mainly due to wrong judgment
2. Confusing and crimping wires. Twisted products are generally supplied in reels. Large cross-sections should be arranged one by one, especially the bottom line should be arranged neatly. When the line is turned around, because there is a stop, special attention should be paid. There should be no too much gap between the upper and lower layers. Appropriate, too large will easily cause line pressure.
Ways to exclude:
1. First of all, adjust the tension of the take-up. When manually arranging the wires, it is advisable to be able to move them.
2. Change the cable pitch according to the diameter of the wire core. Arranging the layers is the key, and they must be neatly arranged; the second layer must be arranged manually when adjusting the layer to ensure the cable quality.
3. Strengthen the sense of responsibility. Observe the quality of the cable at any time, and adjust in time when problems are found, and pay attention to fixing the two thread ends and leaving the distance.
