The uneven twist of the double twister will make the fiber cohesion in each segment of the strand different, and the inclination of the surface fibers will be inconsistent, which will affect the physical and mechanical properties and appearance characteristics of the strand such as strength, elasticity, elongation, gloss and wear resistance. The style and quality of the fabric. For the problem of uneven twist in the double twister, look down.
01
cause
The tension of the dragon belt is uneven
Since the double twisting machine relies on the tangential belt to drive the spindle to twist the strands, the tension of the tangential belt directly affects the spindle speed of the entire car. Because the dragon belt itself has a certain elasticity, and its tension is greatly affected by the climate. In autumn and winter and when parking for a long time, the large shrinkage of the dragon belt causes the tension to increase, which increases the spindle speed, and the opposite is true in spring and summer.
The position deviation of the tensioner in and out
The entry and exit position of each tensioner will directly affect the spindle speed of two adjacent spindles, and there are strict requirements for the entry and exit positions of the tensioner in the technical conditions of the equipment. Practice has found that the deviation of each adjustment unit will affect the proximity of the dragon belt and the spindle, which will increase the spindle speed deviation.
Insufficient spindle lubrication
When the spindle rotates at high speed under the friction drive of the dragon belt, it simultaneously acts on two torques, one is the rotational torque caused by the friction force of the dragon belt, and the other is the resistance torque caused by the friction force of the spindle and the spindle foot bearing. The magnitude of these two moments directly affects the size of the spindle speed. The function of the spindle oil is to form an oil film between the spindle tip and the spindle gallbladder to reduce the frictional resistance of the bearing to the spindle. Therefore, the lubrication of the spindle directly affects the spindle speed. The change of spindle speed will inevitably cause the uneven twist of the strand, and the uneven twist increases with the increase of the difference rate of the change of spindle speed.
The size of the chuck bearing is not flexible
The large and small chucks of the double twister rely on the rotation of two small bearings to realize the rotation and winding of the bobbin. If the rotation of the chuck bearing is not flexible or the clamping force of the cradle to the bobbin is insufficient, it may affect the normal yarn feeding speed. The speed of the yarn pulling speed will inevitably cause uneven twist of the strands, and the greater the difference in yarn pulling speed, the more serious the uneven twist of the strands.
Bad flyer operation
If the production environment of the double twister is not good, such as the flying of flowers or the poor cleaning of the machine, it will cause the flowers to be caught between the flyer and the spindle tube, which will cause the flyer to stumble when it rotates, resulting in uneven twist.
Improper setting of tension spring parameters
In the early stage of production of the TDN-120 double twisting machine used by our company, the twist unevenness of several double twisting machines has been on the high side, and it was once above 3.5 percent . After research, it was found that the main reason was that the setting value of the tension spring in the spindle tensioner was too small, resulting in a high twist unevenness.
02
solution
technological design
Spinning tension adjustment. Different varieties use different spinning tensions. The basis for judging the size of the tension is that it is more appropriate to wind the yarn around the yarn output wheel on the spindle for 1.5 to 2.0 laps, and the maximum should not exceed 2.5 laps.
Reasonably determine the spindle speed. Under normal circumstances, it should be determined according to the situation of broken ends at the time of thousand ingots. The end breakage of fine yarn and high-grade yarns should be controlled within 5 yarns, and the medium and thick yarns should be controlled within 10 yarns. On the basis of meeting the requirements of output and quality, the spindle speed is maximized. After random sampling inspection, the unevenness of twist can be controlled within 5 percent , and the unevenness rate of the whole vehicle can be controlled within 2.5 percent .
Correct selection of overfeed rate. Changes in the overfeed rate affect the winding tension and thus the winding density of the package. In the case of satisfying the forming, the overfeed rate should be selected according to the fineness of the yarn, which is generally controlled at about 160 percent , so as to reduce the increase of end breaks caused by the winding tension and reduce the chance of uneven twisting.
Equipment status maintenance
Ensure the tension of the dragon belt. Replace the drapery belt that is inflexible and running, and adjust its tension to ensure that the draught belt tension meets the specified standards, and that the tension between the machine and the spindle is consistent. When calibrating with a special gauge, make sure that the distance between the belt and the spindle wheel is about 2 mm or more, and the distance between the belt and the tension roller is about 2 mm or more.
Adjust the pressure the dragon brings to the spindle wheel. The large tension of the dragon belt can increase the contact surface with the spindle wheel and reduce the uneven twist, but at the same time it will increase the loss of the spindle belt. Therefore, under the premise of satisfying the quality, the pressure on the spindle wheel of the dragon belt is small, so as to prolong the service life of the dragon belt.
Check the tensioning device. For the peak twist of a single spindle on the machine, check the wear conditions of the tension head, tension rod and tension head seat in the tension device in time. For the inflexible tension head, it should be replaced and repaired in time; the damaged tension rod and tension head seat and other components should be replaced to ensure that the tension difference of each spindle is the smallest, and the position of the spindle should be adjusted in time to make it contact with the dragon belt face in a more reasonable position.
Check the spindle bearings. Check and refuel the spindle drive bearing of the double twister, and replace the malfunctioning and damaged spindle bearing with the stop to ensure that the speed difference between the spindles is controlled within the internal control index and reduce the chance of weak twist. Strengthen the inspection of spindle operation, remove the deteriorated spindle, reduce the difference of spindle speed and yarn tension of the whole machine, and ensure the consistency of the whole machine.
Operation management
The yarn doubling process reflects the setting of fixed length. According to user requirements, the overall yarn loading and overall doffing mode is adopted to reduce the number of joints in the double twisting process.
Strictly implement the operation method, and improper control of the brake release time will also cause local unevenness, and prevent the untwisted yarn and weakly twisted yarn caused by the piecing process. When the stopper finds a broken end during the tour, step on the brake disc joint. When the joint is completed, twist the joint by hand and release the brake disc for 5 s to 10 s. When the yarn section in the non-twisting area is fully twisted Then release the hand and wrap it on the bobbin. The mastery of the time from releasing the brake disc to winding the knot yarn onto the bobbin is selected according to the twist size, 7 s to 10 s for a large twist, and 5 s to 7 s for a small twist.
The stopper should do a good job of cleaning after doffing, and the residual yarn on the spindle wheel should be dealt with in time to eliminate the reduction of spindle speed caused by entanglement and reduce the chance of weak twist.
The twist of the machine is greatly affected by the power failure and restart. In the production, it is found that the twist unevenness of the machine is 2.9 percent before the power failure, and the test is 4.3 percent after the power failure. When you need to park on holidays, you must ask for the empty car to hand in the car, and then try to drive again.
