Spinning frame modification:

Spinning core spun yarn is carried out on ordinary ring spinning frame, but it needs to be refitted. Different kinds of filament are used, the refitting methods are also different.

a) Spinning the core spun yarn with polyester filament cotton fiber: arrange the polyester filament bobbin on the roving frame of the spinning frame, install the roving in the lower row. The traverse device of the spinning frame is used. The polyester filament is fed to the collector the top of the leather roller combined with the drawn cotton whisker. After twisting, the core spun yarn is formed: this method, because the filament is axially rewound, in the process of rewinding, the filament will inevitably circle along the bobbin When passing the guide wire rod, the circular motion will inevitably produce left right swing. The swing amplitude will change with the unwinding diameter. The unwinding diameter is large, the swing amplitude is also large. When the tension is small, it is bound to make the filament swing left right in the collector, in the middle of the strand, so that the filament the cotton strand are synchronized, affecting the covering effect. In order to solve this problem, a guide wire hook can be installed on the top of the leather roller, so that the filament can be fixed in the middle of the whisker, so that it will be affected by the objective conditions keep synchronous, so that the coating effect is good.

b) Spinning core spun yarn with spandex elastic yarn cotton fiber: a set of spandex active conveying device needs to be installed on the spinning frame. The conveying device is composed of two pairs of rollers on each side, roller bracket, spacer, etc. it is installed above the roving frame, the top roller is 1.8m the ground. The outer diameter of drum is 42mm. Between the two rollers, a casting step is set connected with the roller bracket. 1201 rolling bearing is selected in the step. In order to avoid the spandex bobbin moving horizontally on the drum, a steel skin spacer plate with thickness of ∮ 102x 1mm; is welded on the back of each pair of drum, so that the spandex bobbin is positioned horizontally on the drum according to the distance between spindles. At the same time, because the horizontal movement of the unwinding of the spandex fiber drum is about 12 times of that of the cotton fiber in drafting, in order to reduce the difference between the movement of the spandex fiber the cotton fiber, a spandex fiber horizontal movement control ring is added at 370mm above the vertical of the collector, the inner diameter of the control ring is less than equal to the horizontal movement 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 covering effect, the traverse device of the spinning frame is no longer used. At this time, in addition to the fixed guide wire hook installed on the top of the leather roller, the collector of appropriate caliber should be selected. The type fastness of the collector have specific requirements. Because of the geometry of the collector, it is very important to improve the cladding performance of the fiber. Through practice, the core spun spandex yarn uses 79-2v type collector with good covering performance. In the middle of the collector opening, a V-guide wire slot (length 2.5mmx width 0.5mm: 2x depth 0.30mm) is designed. The core of the core spun yarn can be guided positioned in the middle of the core spun yarn bundle after entering the collector, so as to ensure that the spandex spun by the front roller is axially at the corner top of the twisting triangle area of the outer fiber, which is conducive to the uniform coverage of the outer fiber the reduction of the yarn strength unevenness.

d) The use of steel wire ring: the following problems should be paid attention to in the selection of steel wire ring for spinning core spun yarn: the yarn channel of steel wire ring should be larger, the section should be thin bow. In general, the weight of the yarn is more than two grades than that of the same pure cotton, the change cycle is 1 / 3 shorter than that of the same pure cotton, which has a significant effect on improving the yarn hairiness.

e) Use of steel ring: in order to reduce the broken ends of core spun yarn, it is advantageous to the steel ring with wide edge. The yarn channel of the steel ring corresponding to the wide edge steel ring is larger, the service life of the chromium steel ring is longer, which is beneficial to improve the yarn hairiness. For example, when spinning 18.45-16.4tex (32-36s) spandex core spun yarn 13.12-11.8tex (45-50s) polyester core spun yarn, 3.2mm wide steel collar is adopted, the effect is better the hairiness is less.

It is difficult to join the spun yarn when spinning the core spun yarn, especially the spandex core spun yarn. The key to the quality of the elastic core spun yarn is the "hollow core" "bare core tail" of the joint. Because the core spun yarn takes filament as its core, after the end is broken, the filament output by the front roller the wrapped short fiber are sucked by the cotton suction pipe, the longer the time is, the longer the spandex yarn is sucked in, the wrapped cotton is single fiber, the tension of the filament is greater than the short fiber suction, 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 naked silk the front roller to the mouth of the flute tube is biased outside the yarn, which is called "naked core tail". After the end of the spun yarn is broken, the twist of the end of the yarn wound on the bobbin is less loose, which makes the spandex core yarn retract towards the length direction, which is the main reason for the "empty core" of the joint of the elastic core spun yarn. The specific requirements for core spun yarn joint operation are as follows.

Joint length - two hand joint: one hand joint, one hand cutting the filament core with scissors, is the main feature of core spun yarn joint operation. According to the test, when the length of the core spun yarn joint is about 40-50mm, the strength of the joint section can be ensured to be close to that of the normal section. In addition to emphasizing the "simultaneous" use of both hands, the elastic core spun yarn joint should also pay attention to the daily mechanical maintenance work, so that the height of the cotton suction whistle tube is consistent the front middle skin rolls are unified, so as to ensure the standard of the joint length.

Naked core tail - before using the joint with both hands, the core of the filament shall be pre cut once to make the filament lose the suction effect the elasticity retract to the center of the outer fiber bundle. If the quick rebound performance of the filament is fully used to master the opportunity joint of filament reset, the "naked core tail" caused by the joint can be eliminated significantly reduced.

Joint hollow core -- after repeated practice, the joint hollow core can be eliminated by the method of untwisting then twisting. The broken end of the yarn to be wound on the bobbin shall be untwisted for 20 mm to make the ammonia wheel wire retract freely