Slub yarn
The yarn is sometimes thin and sometimes thick, and one section is called a slub yarn.
Slubs were originally a common defect in textile production. Due to some problems such as drafting and uneven thickness during the spinning process, uneven fineness occurs in parts of the yarn, forming a shape similar to slubs. The bulges will produce slub defects and affect the quality of the fabric.
However, when something like this When the bamboo-like protrusions are evenly distributed on the surface of the fabric, they can form a special texture on the surface of the fabric, produce a unique fabric style, and meet people’s requirements for diverse fabric styles. Therefore, during the spinning process, the yarn density is thought to change regularly or irregularly in its length direction, and slub yarn is obtained, and this yarn is used in the production of fabrics to form slub yarn fabrics.
01
Characteristics of slub yarn
It has the appearance of uneven distribution of thickness. It is one of the most types of fancy yarns, including thick and detailed slub yarns, lumpy slub yarns, short fiber slub yarns, and long slub yarns. Silk slub yarn, etc. Slub yarn can be used for both lightweight summer fabrics and heavy winter fabrics. It can be used for clothing fabrics and decorative fabrics. It has outstanding patterns, unique style and strong three-dimensional effect.
02
Principle and method of forming slub yarn
Principle:
An additional device is added to the ordinary spinning frame to change the speed of the front roller.Or it pauses, thereby changing the normal draft multiple, and suddenly a slub appears on the normal yarn, like a slub, so it is called slub yarn.
Method:
Use electromagnetic clutch to control the front roller stopping method
When spinning base yarn : The clutch is in the suction state to maintain the normal operation of the front roller.
Coarse spinning section: The clutch loses power, the moving plate and the static plate are separated,
Stop the front roller + the middle and back rollers are still running? Accumulate the sent fibers between the middle roller and the front roller.
When the clutch is powered on again, the front roller starts to operate again, taking away the accumulated fibers and forming a bamboo joint on the base yarn.
The front roller pauses for a long time? There are a lot of accumulated fibers? The bamboo joints are thick
This This method is suitable for making thicker bamboo joints.
It is also possible to suddenly overfeed the middle and rear rollers, which will also change the draft multiple and produce bamboo joints.
Stepper motor driven front roller speed change method, servo motor driven middle and rear roller overfeeding method, etc.
When using the variable speed of the front roller to produce slub yarn, it has high sensitivity, is suitable for producing denser slubs, and has better control over the length and thickness of the slubs. ability.
Front roller speed change? Will it affect output
Front roller speed sometimes fast and sometimes slow + spindle Is the speed constant? It also affects the twist
When using the middle and rear rollers to overfeed to produce slub yarn, the production of short and dense slubs is not as sensitive as the front roller speed change, and the manufacturing cost is relatively high.
Precautions
﹡When producing slub yarn, the centrifugal force at the slub is relatively large, which causes the air ring to become larger and smaller during production, so the emphasis should be placed on control when selecting a traveler. At the same time, due to the increased thickness of the slub, there is a gap through the traveler. It must be difficult, so a large wire ring should be used.
﹡If the front roller is stopped or variable speed is used to produce slub yarn, the twist should be controlled at a low level.
﹡Producing intensive slubs, due to The speed of the front roller is constantly changing, so the speed should be slowed down appropriately, otherwise the breakage rate of the whole machine will increase.
﹡When stopping the manual doffing, it is best to stop at the base yarn part to avoid the slub. Otherwise, due to the less twist at the slug, the number of ends will increase during driving.
03
Slub yarn application
Currently, commonly used yarns are 12 to 84tex (12 to 83 tex). The raw materials include pure cotton and chemical fiber blended yarns, mainly short fiber yarns, as well as medium-length and woolen fibers.
The length of the bamboo joints generally cannot be less than the length of the fiber. Therefore, the length of bamboo joints spun from cotton fiber is shorter, while the length of bamboo joints spun from wool fiber is longer.
The thickness of the bamboo sections depends on the variety
Because the thickness of the slub is too different from that of the base yarn, and the twist is very small, this section of yarn is not only prone to hairiness, but also prone to hairiness. And the strength is low. Knitted fabrics or woven fabrics made from this yarn have a rough surface and unique style. This kind of yarn is also used to make corrugated yarn on a fancy twisting machine. Because the corrugation at the slub is extremely large and looks like corn, it is also called popcorn yarn.
04
The relationship between the main parameters of slub yarn and the cloth style
Slub yarn parameters include base yarn density, slub thickness, slub length and slub spacing. Due to the special structure of slub yarn, the cloth style is closely related to the above 4 parameters;
Its various combinations determine its special appearance on the canvas There are mainly four methods of style.
1. Since the slub part of slub yarn is thicker, less twist is added to the slub part during spinning, and the bamboo segment The fiber is relatively loose, which causes the thick and thin sections to absorb dye inconsistently when dyeing slub yarn, and the style of raindrops or raindrops will be formed depending on the length of the slub.
2. The styles formed by different raw materials are different: for example, the slubs of slub yarn fabrics made from single yarns spun from ordinary cotton and polyester raw materials are more obvious. ;
Special-shaped fibers such as cationic polyester, high-gloss polyester, viscose, etc. are used to form thinner bamboo joints, and then twisted with ordinary yarn to form threads, which can be made. into high-end fabrics.
3. Spinning 48.6~58.3tex (Nel2~10) slub yarn on a rotor spinning machine, the slub can be higher than 1.3 of normal yarn ~1.8 times, and with the changes in bamboo spacing and length, high-end fabrics with a hemp style can be woven.
4. By utilizing the different lengths, thicknesses, pitches and raw materials of the slub parts of slub yarn, we can develop colorful and different styles. varieties to meet the needs of various consumers.
05
Basic yarn number and comprehensive number of slub yarn
The nominal number of slub yarn is generally It is named after the number of the base yarn. For example, C14.5tex slub yarn refers to the number of normal yarn at the distance between the slubs, and the number at the slub is larger. In actual production, when the front roller is spinning slub at variable speed, the high speed value and twist value of the base yarn are generally set first to spin the normal base yarn number, and then the low speed value and other slub parameters are set to produce slub yarn.
The comprehensive number of slub yarn refers to the base There is a difference between the comprehensive number of yarn and slub yarn, the general process design and the actual comprehensive number spun. The difference in the comprehensive number of slub yarn spun by different types of slub yarn devices is also different. The comprehensive number is an important basis for daily control of the weight deviation of spun yarn in production, and is also the main indicator for cost accounting of cotton used in slub yarn. When spinning slub yarn, some companies use the base yarn number to control the weight deviation of the spun yarn, so that the actual base yarn number spun is lighter and more meters of cloth can be woven. This is acceptable for yarns with thin and sparse slubs, but for slub yarns with thick and dense slubs, the base yarn will be too thin and cause many ends broken during post-processing.
Design comprehensive digital index technology Designed slub yarn comprehensive number. It is the weighted average of the corresponding base yarn and slub yarn numbers based on the percentage of the pitch and length within a certain cycle and the length within a certain cycle as the weight.
It should be pointed out that the total length of a certain cycle of yarn should be calculated based on the arrangement of bamboo joints.
For the regular cycle length, for example, if five bamboo sections make one cycle, the total length of five bamboo sections can be the total length of one cycle; For irregular ones, it can be estimated based on the set average section length, pitch and thickness multiple.
The actual comprehensive number is the actual bamboo spun There is a gap between the knot yarn number and the comprehensive number of process design. Therefore, in daily production, it is necessary to follow the national standards for yarns. Daily tests should control the actual comprehensive number of the finished yarn to reach or be close to the comprehensive number of process design.The weight deviation is controlled at ±2.5% for batches and ±0.5% for monthly deviations.
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