It is understood that when some companies produce CVC 80/20 compact yarn with a count of 100, a large number of defects appear in the roving. For the 100-count yarn produced with Xinjiang cotton, the average number of roving defects per month is only about 1,350. , the number of roving defects of this variety has indeed reached more than 3,500, resulting in many ends of fine yarns and increased labor intensity for employees. For this reason, we have carried out a series of technical research to effectively reduce roving defects and stabilize product quality.
01 Raw material index
We The raw cotton used is PIMA cotton, and the main technical indicators are shown in Table 1; the polyester uses 1.33dtex×38mm cotton-type staple fiber, and the main technical indicators are shown in Table 2.
02 Analysis of main factors
After careful observation and analysis, we believe that the main reasons for the large number of defects in CVC 80/20 compact 100 count rovings are:
(1) PIMA cotton has a high sugar content, and it is easy to stick to the rollers during the production process and cause roving defects.
(2) The official moisture regain of polyester chemical fiber is only 0.4%. It has poor hygroscopicity and is easy to generate static electricity. It is easy to adhere to the rollers and cause defects during the production process.
(3) When two fibers with different properties are blended, the fibers are easily separated to form tops. When the roving is drafted, the exposed fibers are easy to become entangled on the rollers and form defects.
(4) The fiber adhesion is relatively large, and cleaning according to the same cleaning cycle as pure cotton varieties cannot meet production requirements.
(5) Polyester-cotton blended cotton slivers are relatively fluffy. Under the same coil radius, the slivers will rub against the inner wall of the bobbin to form tops, which will then cause roving defects.
(6) The relative humidity in the production area is low and cannot meet the production needs of cotton-polyester blended varieties, causing fibers to form roving defects due to static electricity wrapping around rollers and top rollers.
03 Process research measures
(1) In order to solve the problem of cleaning flannel strips under the roving, which causes the rollers to stick, we changed the original transmission chain from 19 teeth to 21 teeth. This reduces the phenomenon of flannel tape backing and effectively improves the cleaning effect of the rollers.
(2) Adjust the roving roller gauge to 9×24×42mm, and the number of roller sticking times will be significantly reduced.
(3) In order to reduce the top phenomenon behind the roving frame, we changed the guide bar tension wheel from the original 65 teeth to 66 teeth.
(4) In order to solve the problem of tops formed when the sliver hits the inner wall of the grinding barrel, we changed the gear of the transmission ring disc from the original 99 teeth to 101 teeth.
(5) According to the problem that polyester-cotton blended slivers are overripe due to the large number of mixing passes and are prone to accidental drafting and tops, and the rovings are prone to defects, We changed the number of draw frames in the second draw frame from the original 8 to 6 to further reduce the draft multiple. At the same time, we selected a draw frame in good condition as the final draw frame to further improve the tops and fiber arrangement quality.
(6) Every morning, the security charterer will use a clean wrapping cloth dipped in warm water to scrub the front, middle and rear four rollers, and then dry them before driving.
(7) In order to ensure that the production area of this variety maintains good temperature and humidity, we control the area with hanging meters and set up a record book, which is stipulated to be inspected by the production department engineer every day Sign to ensure that the temperature and humidity meet the standards.
04 Effect Verification
Passed With the implementation of the above measures, the roving defects of CVC 100-count yarn have been reduced by 68%, and are controlled within 1080 per month. Achieve the expected monthly goal of less than 1,500. </p
