Article from the laboratory test machines exporter and manufacturer for textile test machines,footwear test equipment,etc. Professional Fiber and Yarn Tester,Single Yarn Strength Tester and Digital Tension Meter Supplier.

Some of the yarn quality problem, such as cotton knot, hairiness is always the main problems of spinning technical personnel, to improving the quality of yarn, cotton knot and hairiness is not around the past a barrier, encounter problems should observe carefully, item by item analysis, the reasons of the problem could be found from the root, take corresponding technical measures to solve the problem, to reduce the problem of link, so as to improve the yarn quality.

1.the nep

The harmfulness of neps

The amount of nep in the yarn not only affects the appearance quality of the yarn and the grey cloth, but also directly affects the dyeing effect of the fabric and causes dyeing defects.

Formation and distribution of neps

(1) the cotton harvest there are many methods can make the raw cotton harvest of nep and impurity is roughly divided into manual picking and harvesting method mechanical harvesting methods, foreign artificial harvesting method is mainly used for picking long-staple cotton and cotton, in addition, shall be given priority to with mechanized harvesting, mechanical harvesting to bring a lot of impurities in cotton, even also has a small amount of nep, to remove impurities difficult cotton ginning mill, also make after crimped wire with a certain number of neps of raw cotton.

(2) there is a contradiction between the removal of impurities in raw cotton and the increase of neps and short lint in the production of clearing. The faster the beater of each part of clearing, the better the removal of impurities.Therefore, it is necessary to make every effort to open the short process of the cotton cleaning production line, optimize the process technology of removing impurities and producing nep, and make every effort to reduce the increase of nep and short pile in the opening of cotton cleaning.

(3) the greater the proportion of immature fibers in raw cotton, the greater the chance of producing neps and short lints. Efforts should be made to control the distribution of immature fibers and reduce the proportion and difference of immature fibers in blended cotton before raw cotton enters the production line for processing.

(4) the carding machine is the main process, reducing neps many nep open or exclusion can be carding on the carding machine, therefore, carding machine to do SiKuai was reasonably, strengthen the carding, especially between flat and cylinder carding effect should be enhanced, the new carding machine is configured with a fixed plate, improve the feed of cotton in the function and the carding effect, these are very important to reduce the nep is to play a role.

(4) the raw cotton neps in online and offline monitoring control, make an increase in the number of control in the production of cotton, the application of AFis raw cotton property tester can check one by one package immature fiber percentage in the raw cotton and cotton knot, in excess of the prescribed indicators to go without, which can control carding neps in the number of each process and new ones such as DK803, DK903, DC03 etc but also dynamic change of on-line detection of nep, according to the increase of nep exception alarm, automatic flat and cylinder, automatic flat grinding, stable product quality.

(5) after long-term practice and inspection of the number of accumulation, the general nep control standards are as follows:

200 pieces of raw cotton /g

Open cotton 400 pieces /g

Carding 80 grains /g

Combed 20 grains /g

Raw cotton according to the initial processing and the quality of raw cotton, the general nep quantity is 200 /g, the minimum is 100 /g, and the maximum is 400 /g.

In the opening and clearing process, the neps were increased to 400 /g, the minimum was 200 /g, and the maximum was 700 /g.

The raw strip of carding machine contains 80 PCS /g, the highest 200 PCS /g and the lowest 50 PCS /g.

After combing and dropping, the nep in the combing strip is generally controlled below 20 grains /g.

Other processes such as drawing, roving and other nep quantitative change is little, but a little increase.

Immature fibers have a great influence on the increase of nep and short pile. The distribution and content percentage of immature fibers in the blending of raw cotton should be controlled.

2. hairiness,

Yarn hairiness is harmful in some textiles, especially warp and weft yarns used in air jet looms, which require that warp and weft yarns minimize hairiness, especially those over 3 mm.But some fabrics have special yarns that contain certain hairiness to give the fabric a certain style.The place where the feather is produced

(1) the main process of producing hairiness is spinning, and there are two places on the spinning frame that have the most influence on producing hairiness.The first is the spinning triangle area, that is, the spinning triangle area between the whisk from the front roller nipper to the twist point. According to foreign reports, the yarn hairiness produced in the triangle area accounts for 80% ~ 85% of the yarn hairiness.The second is the winding part.

(2) the emergence of compact spinning technology basically eliminates the spinning triangle. Therefore, the spun yarn has few hairiness and the yarn body is as smooth as silk, which basically solves the problem of yarn hairiness in the spinning production.

(3) frame roll part of the ring and traveler is to produce the part of the yarn hairiness, most domestic platform, steel wire circle of life is extremely low, ring life only nine months, wire roll life is only a week, because of the ring steel wire circle don't match, the plateau is too short, the warp tension is not very stable, particularly in the production of large and small yarn spinning yarn spinning tension is bigger, the denier will produce beheaded, and will produce hairiness, in recent years, our country ring life after material and machining process of revolution, life has been increased to 3 years to 5 years, steel wire circle of life has improved, like plating fluorine traveler.

Overseas general production ring, steel wire circle is in an enterprise, ring and traveler identical shape to obtain the very good design, prolong the service life and improve the quality of the supporting, like Switzerland brook traveler, ring supporting situation is very good, increased the two contact surfaces, makes the cooling effect is good, prolong the life span, according to the experience of the factory, ring traveler supporting good will significantly reduce hairiness.

Measures to reduce hairiness

(1) roller, rubber roller, rubber ring, yarn guide hook, upper and lower pin, collector and other spinning components all play a certain role in reducing hairiness. It is also a positive measure to reduce the triangle area of spinning as far as possible without compact spinning technology.

(2) the motor of the new spinning frame is variable frequency speed regulating, which can be divided into 10 stages according to the spinning process from small yarn to large spindle speed, so as to control the consistent spinning tension, and stabilize the spinning tension to reduce the yarn hairiness.

(3) yarn hairiness is closely related to the efficiency improvement of air jet loom. According to the investigation, when air jet loom USES ordinary ring yarn, the warp and weft stop contract caused by hairiness accounts for 2/3, so hairiness problem should be paid more attention.

(4) due to the uneven distribution of hairiness and large spindle difference, the fabric will be caused by the horizontal hairiness stain.

(5) the automatic winding machine has realized the automatic control of the winding tension from large yarn to small yarn and the winding tension of the winding machine, which also plays a positive role in reducing the number of hairiness generated by the winding.

(6) the effect of winder on the increase of hairiness is specific to the situation that the hairiness of the common ring yarns is more, and the further deterioration causes the significant increase of hairiness, but it does not include the yarns with less hairiness in the compact spinning. For the tight ring yarns, the winder will not have a significant effect on the increase of hairiness of the yarn.

(7) in the new spinning system, there is basically no spinning triangle and winding system of steel collar and steel ring, so there are fewer hairiness on the spinning lines of air jet spinning, vortex spinning and rotary cup spinning than ordinary ring spinning yarn.

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