1. Reasonable cotton allocation
Rational cotton allocation is the basis for improving yarn quality. Horse value, length uniformity, impurities and harmful defects are the main factors affecting yarn neps. Within a certain horse value range, the higher the maturity, the better the strength and flexibility of the single fiber, the less damage and breakage during the production process, and the less likely it is to become entangled into neps due to friction. The effects of different cotton blends on yarn quality are shown in Table 1.
As can be seen from Table 1, the raw material maturity is poor, the fineness is fine, and the yarn is Neps are significantly elevated. Therefore, the internal control standards for C40S yarn and cotton formulated by our company are: micronaire 4.1-4.4, average fineness 5600-5800 metric count, and average impurity content below 2.4%.
2. Quality control measures for each process
2.1 Blowing and carding link
(1) The impurities in the raw cotton should be removed early and frequently. The cleaning and carding process adopts the process of less grabbing and more combing, and the hand speed of the bag grabbing machine is controlled at 1150-1300r/min, each grabbing depth is 1.5-2.0mm.
(2) JWF1211 carding machine three-needle equipped with Graf card clothing, cylinder P-2035S×0.4 (1280), movable cover C55/0 (1280), doffer N-4030 B
2.2 Drawing
(1) Drawing is based on the process configuration principle of improving the straightening and parallelism of fibers and strengthening the control of floating fibers to control the tension during the drafting process. Nep growth rate.
(2) According to the hook principle, adopt the process configuration of smooth drafting, the drafting multiple of the first and rear area is 1.90-1.98, and the drafting multiple of the last and rear area is 1.19-1.25 .
(3) Choose a lower sliver delivery speed and set an appropriate full can sliver length to avoid looping and linting of the sliver. The delivery speed is 340m/min at the beginning and 310m/min at the end.
2.3 Roving
Replace in time For worn false twisters, maintain the surface finish of the false twisters and strengthen the cleaning of the drafting area.
2.4 Spinning yarn
Use relatively The jaw spacing is small to enhance the fiber control ability. The spacing block is changed from the original 2.5mm to 2.25mm. The effect comparison is shown in Table 3.
2.5 Winding
On the premise of ensuring the cleanness of the yarn channel, appropriately reduce the yarn tension to prevent part of the hairiness from being rubbed into neps. Optimize the winding speed, reduce it from the original 1300 r/min to 1200 r/min, and reduce the tension appropriately. The optimization effect is shown in Table 4.
3. Research results
After taking research measures in each process, the neps per kilometer of C40S yarn have been significantly reduced, and the results are remarkable. The yarn quality indicators are shown in Table 5.
4. Conclusion
Reducing kilometer neps in yarn is a systematic project. We should start from various aspects such as raw materials, equipment, and technology to find the key factors that affect the neps of the yarn, and take corresponding measures in a targeted manner to achieve the expected results. </p
