Прядіння пряжі з серцевинним прядінням

There are two spinning methods of core spun yarn: one is to discharge polyester filament (or other filament) on the roving frame of ordinary spinning frame, and put cotton roving (or short fiber roving) on the lower row. The cotton roving is fed through the trumpet mouth of the transverse device, and then through the drafting device. After the polyester filament is drawn out, it is directly introduced into the collector at the back of the front roller without the drafting device, combined with the drafted pure cotton whisker, and then twisted into a core spun yarn. The second spinning method is to feed two filaments behind the front roller, so that the two filaments and the drawn pure cotton whiskers are combined and twisted to spin into core spun yarn. This spinning method is called modified core spun yarn or false core spun yarn. The second spinning method is characterized in that two filaments are located on both sides of the periphery of the cotton whisker, which increases the holding force between the short fiber and the filament, and reduces the peeling phenomenon during weaving because the first method wraps the cotton fiber on the surface of the yarn, while the polyester filament is in the middle of the yarn. However, in mass production, the first method is still generally used, because a filament is easy to spin into a core spun yarn with more cotton content, the woven fabric is comfortable to wear, and a filament is easy to spin into a finer core spun yarn, while the core spun yarn produced by the false core spun yarn method is just the opposite. If the core wire is spandex elastic wire, when spinning the core spun yarn, a pair of filament feeding rollers shall be added to the filament leading out part of the upper roving frame, and its surface speed shall be lower than that of the front roller, so that the elastic wire can be pre drawn, and its elongation shall be controlled to a certain extent. After feeding, it shall be combined with the short fiber whisker and twisted to form the core spun yarn. The modification of spinning frame to spin core spun yarn is carried out on the ordinary ring spinning frame, but the spinning frame needs to be modified. The varieties of filaments used are different, and the modification methods are also different. a) Spinning core spun yarn with polyester filament and cotton fiber: the polyester filament bobbin is arranged on the roving frame of the spinning frame, and the roving is arranged on the lower row. The traverse device of the spinning frame is not used. The polyester filament is fed from the top of the roller, combined with the draft cotton whisker, and spun into core spun yarn after twisting: this method, because the filament is unwinded axially, in the unwinding process, The filament is bound to make a circular motion along the bobbin. When passing through the wire guide rod, it is bound to swing left and right, and its swing amplitude changes with the unwinding diameter. The unwinding diameter is large, and the swing amplitude is also large. When the tension is small, it is bound to swing left and right in the collector, not in the middle of the whisker, so that the filament and the cotton whisker are not synchronized, affecting the coating effect. In order to solve this problem, a wire guide hook can be installed above the leather roller, so as to fix the filament in the center of the whisker, keep it synchronized without the influence of objective conditions, and promote good coating effect. b) Spinning core spun yarn with spandex elastic yarn and cotton fiber: it is necessary to install a set of spandex active conveying device on the spinning frame. This conveying device is composed of two pairs of rollers on each side, roller bracket, spacer, etc. it is installed above the roving frame, and the top roller is 1.8m away from the ground. The outer diameter of the drum is 42mm. A casting step is set between the two rollers and connected with the roller bracket. 1201 rolling bearing is selected in the step. In order to avoid the spandex bobbin moving laterally on the drum, weld ∮ 102x 1mm thick on the rear drum of each pair of drums; The steel skin spacer enables the spandex bobbin to be positioned laterally on the drum according to the spindle spacing. At the same time, because the unwinding transverse motion of the spandex bobbin is equivalent to about 12 times of the transverse motion of the cotton fiber during drafting, in order to reduce the motion difference between the spandex and the cotton fiber, a spandex transverse motion control ring is installed 370mm vertically above the collector, and the inner diameter of the control ring is less than or equal to the transverse motion of the cotton fiber, which is beneficial to improve the uniformity of the outer fiber. c) Use of collector: in the spinning process, in order to obtain good coating effect, the traverse device of the spinning frame is no longer used. At this time, in addition to the fixed wire guide hook above the leather roller, the collector with appropriate diameter should be selected. The type and fastness of the collector have specific requirements. Because of the geometry of the collector, it is very important to improve the coating performance of the fiber. Through practice, 79-2v collector is used to spin spandex core spun yarn, which has good coating performance. In the middle of the collector opening, a V-shaped wire guide groove (length 2.5mm x width 0.5mm: 2x depth 0.30mm) is designed. After entering the collector, the core wire of the core spun yarn can be guided and positioned in the middle of the whisker bundle, so as to ensure that the axial direction of the spandex wire discharged from the front roller is the corner top of the twisting triangle area of the outer fiber, which is conducive to the uniform coating of the outer fiber and reducing the unevenness of yarn strength. d) Use of steel wire ring: the selection and matching of steel wire ring for spinning core spun yarn should pay attention to the following problems: the yarn channel of steel wire ring should be larger, and the section should be thin bow. The weight is generally two grades heavier than that of the same pure cotton, and the switching cycle is 1 / 3 shorter than that of the same pure cotton, which has a significant effect on improving yarn hairiness. e) Use of steel ring: in order to reduce the yarn breakage of core spun yarn, it is beneficial to select the steel ring with wider edge, the yarn channel of the steel ring corresponding to the wide edge steel ring should be larger, and the service life of chromium steel ring is also long, which is beneficial to improving the yarn hairiness. For example, spinning 18.45-16.4tex (32-36s) spandex core spun yarn and spinning 13.12-11.8tex (45-50s) polyester core spun yarn, using 3.2mm wide steel collar, the effect is better and the hairiness is less. The spinning joint is difficult when spinning core spun yarn, especially the joint of spandex core spun yarn, especially the problems of "empty core" and "bare core tail" are the key to the joint quality of elastic core spun yarn. Because the core spun yarn takes the filament as the core, after the end is broken, the filament output from the front roller and the wrapped short fiber are sucked by the cotton suction tube. The longer the time, the longer the inhaled spandex fiber is, while the wrapped cotton is sucked by a single fiber. The tension on the filament is greater than the suction of the short fiber, resulting in the disintegration of the two, that is, the filament cannot be kept in the center of the wrapped fiber. Therefore, after the joint, a section of bare wire from the front roller to the flute nozzle is biased outside the yarn, that is, the "bare core tail". After the end of the spinning yarn is broken, the twist of the yarn end wound on the bobbin is less and loose, which makes the spandex core wire retract to the length direction, which is the main reason for the "empty core" of the elastic core spun yarn joint. The specific requirements for core spun yarn joint operation are as follows. 7.1 joint length: use both hands together: that is, use scissors to cut the filament core with one hand, which is the main feature of cored yarn joint operation. According to the test, when the length of the core spun yarn joint is about 40-50mm, it can ensure that the strength of the joint yarn segment is close to the normal yarn segment. In addition to emphasizing the "simultaneous" use of both hands, the elastic core yarn joint should also pay attention to strengthening the daily mechanical maintenance, so as to ensure that the height of the cotton suction pipe is consistent and the front and middle leather rollers are unified, so as to ensure the standard of the joint length. 7.2 before using the joint with both hands, the filament core shall be pre cut once to make the filament lose the suction effect and the elastic force retract to the center of the wrapped fiber bundle. If we make full use of the rapid rebound performance of the filament and master the filament reset opportunity joint, we can eliminate or significantly reduce the "bare core tail" caused by the joint. 7.3 after repeated practice, the joint hollow core can be eliminated by untwisting and twisting. The broken yarn end wound on the bobbin shall be untwisted for 20mm, the ammonia wheel wire shall be retracted freely, and the outer fiber of the emerging spandex wire shall be pulled, and then the untwisted yarn end shall be properly twisted by hand, and the joint shall be made immediately, so that the joint quality is good.