The main physical properties of raw cotton, such as length, linear density, strength, maturity and impurity content, are closely related to the spinning process and yarn quality. In order to fully utilize and rationally utilize the characteristics of different raw cottons to ensure quality and reduce For the purpose of cost and stable production, cotton spinning mills combine different grades of cotton to form mixed cotton. This method of using multiple raw cottons is called cotton blending.
The purpose of matching cotton
a) Keep production and yarn quality relatively stable. In order to produce with high quality and low consumption, the production process and yarn quality are required to remain relatively stable. Keeping the properties of raw cotton relatively stable is an important condition for stable production and quality.
b) Reasonably use raw cotton to meet yarn quality requirements; use mixed cotton spinning to make full use of the characteristics of various cottons, learn from each other’s strengths, and meet yarn quality requirements.
c) Save cotton and reduce costs; raw cotton is priced according to quality, and the prices of raw cotton of different lengths and grades vary greatly. Raw cotton accounts for about 80% of the spinning cost. If the raw cotton grade is higher, although the quality of the yarn can be guaranteed, the production cost will increase. Therefore, when distributing cotton, we must start from the economic benefits, control the unit price of cotton and the amount of cotton per ton of yarn, and strive to save cotton and reduce costs. Increase cotton distribution technology and rationally use all levels of cotton spinning.
How to make full use of low-grade cotton
1 Strengthen inspection
Inspection work must be strengthened for low-grade cotton, especially package-by-package inspection, and classification and stacking based on color characteristics, impurity content, and maturity. According to their strength, number, short velvet, etc., they are divided into three categories: upper, middle and lower for queuing. Further understand the spinning performance through single-mark trial spinning.
2 Reasonable use
Strive to stabilize the use of low-grade cotton, and gradually blend it into large queues in stages. Use less first and then more or individual yarn numbers first, and then promote it on a large scale after experience is gained.
3 Make full use of the inherent advantages of low-grade cotton
a) Make full use of the favorable conditions of fine low-grade cotton fibers to improve the strength of the yarn. Fiber fineness means that the number of fibers in the cross-section increases relatively, and the friction between them increases and they are less likely to slip off. When the yarn number is constant and the number of fibers in the cross-section is larger, it is beneficial to evenness. The fibers are thin and soft, easy to draw, and evenly wound, so the yarn strength is also relatively uniform.
b) Taking advantage of the long length of low-grade cotton fibers and using long fibers to spin yarn, the overlapping parts of the yarn will also be longer, which will increase the friction and cohesion between the fibers, and the yarn will be stronger. In general, the longer the cotton fiber length, the higher the spinnable yarn count, and vice versa. For every 1 mm increase in quality length, the yarn strength can be increased by 1% to 2%, or even higher. Generally, the length of low-grade cotton is longer, mostly 28 mm to 29 mm.
c) Utilization of color. When the amount of low-grade cotton is within 10%, the cotton yarn can be made creamy. However, if mixed too much, the cotton yarn and cotton cloth will turn yellow. Properly used, the fabric will be plump, cotton will not show up, and the stripes will be clear.
4. Adjust the process appropriately
The quantity of each process should be appropriately reduced, loosening and carding should be enhanced, and the impurity removal effect should be increased. Enhance the control of floating fibers and improve the straightness and parallelism of fibers.
a) The cotton should be loosened as much as possible and beaten as little as possible. Increase the distance between the dust rods of the cotton box machine appropriately to reduce recycling. Rely on centrifugal force to remove more impurities. Reduce the distance between the inclined curtains of the cotton box machine and increase the height and length of the horns appropriately to facilitate loosening. The speed of the beater should be appropriate and should not be too fast. , so as not to damage the fiber; speed up the speed of the cotton leveling roller to increase the mixing effect, increase the opening effect, and can open the fiber without damaging the fiber, which is beneficial to the removal of impurities and short lint; appropriately increase the impurity removal points, and appropriately reduce the distance from the beater to the dust rod. Small, the opening degree is enhanced, there are more fallen objects, and more impurities are removed; the fan speed is appropriately increased at the entrance of each cotton box to allow the air flow to be supplemented from the top or side, reducing recycling and increasing impurity removal.
b) Carding adopts a strong carding process to remove more small impurities and short lint. Appropriately increase the speed of the cylinder and licker-in to increase the piercing and carding capacity of the licker-in; the distance between the licker-in roller and the small drain bottom is 4.5, and the air flow is slow, reducing recycling; appropriately speed up the cover plate speed and reduce the distance between the cover plate and the cylinder, and more Discharge short lint; slow down the doffer speed to enhance the carding effect and improve the clarity of the cotton web; reduce the dust collector and shorten the small drain bottom to increase the debris area; the lower opening of the cylinder rear cover is larger than the distance from the cylinder to the large drain bottom , so that the airflow can be smoothly directed to the direction of the small drain bottom without generating eddy currents; the distance between the large drain bottom and the cylinder is appropriately enlarged to ease the airflow. The purpose of the above process adjustments is to strengthen carding and eliminate short lint and impurities as much as possible, as well as to appropriately increase the number of needle copying and to complete the machine according to “four fast and one straight” to keep the equipment in normal condition.
c) Appropriately reduce the roller spacing and increase the pressure during the merging, coarsening, and fine processes to achieve the purpose of effectively controlling and reducing free fibers, increasing fiber straightening and parallelism, and improving evenness of evenness. The twist coefficient of the roving should be appropriately increased to increase the cohesion between fibers.
Quality first and overall consideration means handling the relationship between quality and cotton conservation. Comprehensive arrangements and ensuring the key points are to find out the cotton trends and raw cotton quality in a timely manner, and to keep abreast of product quality information and feedback, so as to allocate raw cotton flexibly and carefully. In short, reasonable and scientific use ofGood low-grade cotton is of great significance for rational utilization of resources and increasing the competitiveness of enterprises in the market.
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