1 The importance of air splicers in the self-winding process
In the winding process, the yarn needs to be made into a shape that is conducive to continuous production in subsequent processes. large bobbin, and at the same time remove some defects on the yarn. Whether the bobbin is rolled into a large bobbin or the defects are removed, two sections of yarn need to be knotted, and there is a considerable amount of yarn in each bobbin. Joints, taking the Murata 21C automatic winding machine as an example, the number of joints per machine per day: If the bobbin length is 5000 meters, the winding speed is 1200 meters/minute, and each winding machine has 60 spindles, for example, the twist The number of knots is 24 hours × 60 minutes × 1200 meters/minute × 60 knots ÷ 5000 meters, and there are 20736 twisting times. This does not include the joints caused by removing defects. It can be seen that such a large number of twisting knots, Quality has a great impact on subsequent processes. The downtime loss caused by splicing is expensive. According to relevant literature reports, a rough estimate is that the economic loss caused by a single yarn being broken during winding and other subsequent processes is Output: The end-break loss in warping is about 700 times that of winding, the sizing is about 2000 times that of winding, and the weaving loss is about 490 times that of winding. Therefore, to produce high-quality rolling packages, improve the various aspects after winding. It has become inevitable to improve the efficiency of the process and reduce the economic losses caused by yarn breakage.
2 Some factors affecting splicing quality and improvement methods
The splicing process of the air splicer is composed of two processes: untwisting and twisting. Under normal conditions such as the untwisting tube, twisting cavity, length adjustment rod and other process parameters Under the conditions, the ideal untwisting and twisting result is a joint with uniform structure, good appearance and considerable strength. The strength retention rate of the joint is generally above 85%. The appearance diameter of the joint is 1.2-1.4 times the diameter of the original yarn, and the length is 2.5 -75px. If it is lower than this standard or various conditions occur, then our maintenance ideas should also start from these two processes and eliminate them one by one.
Exclude external causes (such as the quality of the yarn itself, workshop temperature and humidity, mechanical influences, etc.)
2.1 Analysis of the reasons for high twisting error rate
The main reasons for high twisting error rate are the following five aspects:
(1)P1 and P2 quick connectors are not plugged in properly.
(2) The air volume of the air splicer is improperly adjusted or the splicing solenoid valve fails. Listen to the different sounds of untwisting and twisting. If there is untwisting but not twisting, or twisting but no untwisting, check the air volume regulating valve and solenoid valve of the air twister. Clean or replace the solenoid valve and make sure the air volume reaches the standard. That will solve the problem.
(3) Insufficient untwisting is manifested as short untwisting length. This is mainly because the untwisting tube is further back than the normal position. The untwisting tube should be adjusted outward. , increase the air intake, and adjust it in units of 0.1 mm. When the untwisting is insufficient, it can also be solved by rotating the untwisting tube. Z-twisted yarn rotates the untwisting tube counterclockwise. The greater the twist, the greater the rotation amount.
(4) The splicing length is too short, Ln is from Ln8 outward to Ln1 (adjusted according to the variety).
(5) The pressing amount of the yarn pressing rod should be 2-3mm, and the opening width of the yarn pressing rod corresponds to the width of the splicing bottom plate (front panel) separator (the gap is 0.5 mm), the pressing amount is adjusted using the yarn pressing rod adjusting screw.
2.2 Analysis of causes of twist joint slippage
As a result, twist joints are prone to slippage The reasons mainly include four aspects:
(1) The twisting pressure is too low, increase the twisting pressure appropriately, and adjust P2 decompression according to the yarn type and count. Valve, the adjustment amount is 0.2-0.65Mpa. Insufficient holding force, that is, the twisting is not tight, is related to the strength of the air vortex, and the strength of the air vortex is not only related to the twist control itself, but also related to the intensity and speed of the twisting air vortex. The working effect of the twisting and pressing cavity is generally fixed, and there is no adjustment part. Its work depends entirely on the size of the twisting air pressure and the length of the action. If you find this situation, check whether the twisting cavity is cracked, whether there are grooves in the cavity cover rubber, whether the cavity cover and the bracket are tightly matched, whether the screws are tightened, and whether the untwisting tube is damaged or defective. Timely replacement or adjustment can solve the problem.
(2) The twist joint is too long, adjust the length of the twist joint reasonably, and move Ln from Ln1 to Ln8 (according to the variety).
(3) Insufficient untwisting, please refer to point 3 of splicing errors to solve the problem of insufficient untwisting.
2.3 The twist knot is thin and the strength is low
Cause this There are three main reasons for this phenomenon:
(1) The twisting pressure is too high, the twisting pressure should be reduced and the P2 pressure should be adjusted.
(2) The splicing length is too short, adjust Ln8 outward to the appropriate length.
(3) Excessive untwisting, which is manifested in that the untwisting length is too long, the head is thin and messy, and small white spots appear at the joints. This is because the position of the untwisting tube is relatively The normal position is towards the front, the untwisted joint is too long, and the end fibers are not fluffy or the front ends of the fibers are entangled with each other, causing neps to form at both ends of the joint or details appearing at the joint. In this case, there is a certain strength, but the strength is different. If it is larger, the untwisting tube should be adjusted inward to reduce the air intake. The adjustment is also performed in units of 0.1 mm. Drag long tails at both ends of the twist joint, adjust the Ln position, move Ln forward, and at the same time check the twisting strength to determine the best position.
2.4 One side of the splice is thick and there is a tail
Cause There are three reasons for this phenomenon:
(1) The twisting scissors are defective and the splicer should be properly repaired.Maintenance work, cleaning the flying flowers on the scissors or replacing the scissors.
(2) The upper or lower yarn is not clamped properly. The yarn guide rod may have flying flowers attached to it or the yarn guide rod may be deformed and have marks, causing the clamping to not be in place. Remove the flying flowers and replace the yarn guide. A rod can solve it.
(3) The position of the untwisting tube on one side is poor, which can be solved with a little adjustment.
Through a series of targeted adjustments and maintenance, the yarn splicing quality has been significantly improved, and the splicing error rate has been reduced by less than 10% from the original 22.4%.
3 Conclusion
The splicer plays an important role in modern spinning The unique mechanical parts of jointless yarns have a great impact on the subsequent processes. To ensure good quality, the adjustment of process parameters such as untwisting, twisting, and joint length is crucial. The air splicer is the core component of automatic winding to ensure quality. The use of the splicer improves the internal and external quality of the package yarn, and also improves the production efficiency of subsequent processes. In actual production, for different raw material yarns , number, should be adjusted according to the actual situation to ensure the splicing process parameters to ensure the quality of the joint and achieve the purpose of stability, strength, efficiency and quality. </p
