1 Quality index of combed sliver
Combed cotton yarn is used to spin high-grade products, so the quality requirements for combed sliver are extremely high. Due to different spinning varieties, raw cotton conditions, and production conditions of each factory, the control range of quality indicators for combed sliver varies.
2 Reduce nep impurities and combed yarn defects
The quality requirements of combed cotton yarn are high, with the number of neps and impurities being more than half less than the number of particles of the same linear density combed cotton yarn, because the comber can remove a considerable amount of neps and impurities, especially for impurities with a removal rate of 50% to 60%, and for neps with a removal rate of 10% to 20%.
To reduce neps, impurities, and yarn defects, in addition to rationally selecting raw cotton, giving full play to the impurity removal role of the cotton cleaning and carding processes, and preventing neps, the following points should be noted in the combing process:
(1) Improve the small roll preparation process, improve the quality of the small roll, strive to improve the vertical and horizontal uniformity of the small roll and the fiber straightness and parallelism, in order to fully play the carding role of the combing machine.
(2) Improving the mechanical state of the carding machine, especially the carding needle state, is the key to improving the carding effect. For example, adjust the specifications and planting density of the comb needle of the cylinder and top comb reasonably, keep the needle in good working condition without needle shortage, trim the brush in a timely manner, improve the smoothness of the brush, maintain the elasticity of the bristle, improve the working efficiency of the brush, and ensure that the surface of the cylinder needle can be cleaned.
(3) Correctly master the combing process, reasonably adjust the separation roller clockwise rotation timing, cylinder bow plate positioning, clamp plate closing timing, and carding interval.
(4) Reasonably master and control the combing noil rate. According to the quality requirements of the spun cotton yarn, reasonably determine the noil rate, pay attention to the noil state at any time, and reduce the stage difference and eye difference of the noil.
(5) Strengthen operation management. During operation, attention should be paid to the sticking of small coils to prevent unclear layers or damage to the carding needle when feeding thick layers, which may affect the quality of the cotton web. At the same time, it is necessary to correctly formulate and effectively implement the cleaning cycle of each part of the combing machine, adopt better pile plate structure and materials, and reduce combing yarn defects.
3 Reducing sliver unevenness of combed cotton
Due to the periodic separation and combination of the output webs of the comber, the combed sliver has a large periodic fragment unevenness. After the combination of the subsequent processes, the periodic unevenness of the combed sliver can be greatly reduced. Moreover, due to the good separation and straightness parallelism of the fibers in the combed sliver, and the fewer short fibers and defects, it is beneficial to the drafting of the subsequent process. Therefore, the combed sliver has a good evenness.
There are many factors that affect the evenness of combed sliver. On the basis of improving the quality of the small roll and maintaining the normal mechanism state, the following points should also be noted:
(1) Reasonably adjust the process parameters and correctly timing and positioning;
(2) Correctly control the tension and draft of each part to reduce accidental elongation;
(3) Keep the passage through which the cotton web and sliver pass smooth and clean;
(4) Strictly control the temperature and humidity in the workshop, so that the temperature and humidity in the workshop are controlled within the specified range, that is, the temperature is 20 to 30 degrees Celsius, and the relative humidity is 55% to 60%, to avoid problems such as improper temperature and humidity control, such as roller winding, roller winding, cotton mesh edge breaking, and coil diagonal pipe blocking.
