The essence of spinning is to ensure that the fibers are arranged in an orderly fashion along the axial direction. To accomplish this task, carding in the textile is the basis and the key. The main task of carding is to break down the cotton bundle into individual fibers and temporarily complete the work of fiber orientation while removing neps impurities and some short fibers. Below we summarize the factors that affect the quality of carding and perform a simple analysis.
Content
1 Raw cotton 1.1 Maturity of cotton fiber 1.2 The fineness of cotton fiber 1.3 Effect of length of raw cotton 1.4 The influence of uniformity of raw cotton 1.5 Number and content of defects 2 Chemical fiber 3 Carding component factors 4 Carding machine mechanical condition factors 5 Yield factorRohbaumwolle
The main factors influencing the carding quality of raw cotton are fiber maturity, fineness, micronaire value, cot on the linters rate and the number and content of defects in raw cotton.
Cotton fiber maturity
Maturity is a comprehensive index for assessing the intrinsic quality of cotton fibers. It directly affects the color, strength, fineness, natural twist, elasticity and moisture absorption, dyeing and other properties of cotton fibers.
Mature cotton fibers have many natural twists, good elasticity and good color. It is not easy to form nubs and short fibers when carding. After carding The fiber separation, straightness and parallelism are better.
When the ripeness is poor, the fineness is fine, the strength is low and the length is long, the carding processing is more difficult. At this time, the distance between the cotton board and the pricking stick, as well as the distancebe increased accordingly between the main carding area and the speed reduced.
The fineness of the cotton fiber
Fibers with normal maturity and finer fineness feel soft and elastic, with good fiber cohesion and high strength. Under the same quantitative conditions, the number of fibers is large, they can be easily caught by the needle teeth, and the carding force is relatively large. When the fiber is not mature enough, although the fiber is mature thin, the elasticity is poor, and short fibers and neps are easy to form when carding, which affects the carding quality.
Effect of the length of raw cotton
The Length of fibers in raw cotton is not only an important index for measuring the quality of raw cotton, but also an important factor for determining yarn quality. The early theory assumed that the length of the cotton fiber was positively correlated with the yarn quality, i. H. the longer the fiber length, the better The yarn quality. However, upon further investigation, a different view was taken, that is, fiber length is positively correlated with yarn strength quality index, but not with yarn roughness index. When the fiber length is between 2and 4 cm, the unevenness of the yarn increases to a certain extent as the fiber length increases, and its growth rate is closely related to the yarn count. Of course, this is the conclusion that the theoretical model calculated, and whether it agrees with actual production must be verified by production practice, but also shows that the influence of fiber length on the quality of the yarn cannot be ignored .
The influence of the evenness of the raw material cotton
The fiber evenness of raw cotton is the key factor for the sliver and yarn quality of the card. Raw materials with high fiber uniformity have significantly better rawFor example, the uster evenness CV of pure cotton card sliver is currently generally around 3.5%, while the uster evenness CV of card sliver from chemical fibers is generally around 2.8%. One of the important factors is that the fiber regularity of ordinary raw cotton is less than 80%, while the regularity of man-made fibers is usually over 95%.
Number and content of defects
There are three types of impurities in raw cotton.
The first category are contaminants that are easy to remove, such as leaf sediment and cottonseed.
The second category are contaminants that are easy to break up, difficult to remove, and have a greater impact have yarn quality during cleaning, e.g. B. sterile seeds, fibrous stick shavings, broken seeds, etc.
The thirdte category are harmful defects that are difficult to remove and obviously affect the quality of the yarn, such as soft seed coats, stiff flakes, yellow roots and foreign fibers.
In addition, the wires and neps in the raw material , especially the tightly wound wires and neps, are difficult to remove when carding , which increases the number of neps and impurities in the yarn.
Manmade fiber
Among all man-made fibers, the coefficient of friction has the greatest impact on spinning performance and carding quality resistivity and the resistivity of the fiber. In the carding and drawing process, the static friction coefficient (Us) and dynamic friction coefficient (Ud) of fiber and fiber, fiber and carding element, fiber and drawing element have a good relationship with the effect of carding and drawing.
The carding effect is closely related to the opening element. The carding and carding components mainly includechlich clicker-in roll clothing, cylinder clothing, doffer clothing, fixed flat clothing and movable flat clothing. Fiber carding is a continuous carding process. Transmission, re-carding and re-transmission. Only by properly solving the relationship between carding and transfer can we achieve complete and perfect combination, blending and transfer, and achieve the best carding effect and carding quality.
The card is the carrier that performs various carding processes and completes the entire carding process. If the manufacturing accuracy of the card and the flatness of the card clothing are necessary conditions to ensure carding efficiency, then the mechanical condition of the card is a sufficient condition.
From the perspective of long-term production practice
The performance and the quality of the card are two contradictions that in come more to the fore during this phase. The card\'s ability to eliminate defects in the mat cotton is referred to as carding efficiency. Subject to the condition Disregardother factors, the degree of carding is relatively fixed. As the number of defects in the raw material increases, the card\'s carding efficiency and carding quality inevitably decrease. The increase in the performance of the card means that the amount of mat cotton processed per unit time increases, which inevitably leads to a deterioration in the carding efficiency and carding quality. In order to ensure the carding efficiency and carding quality, it is necessary to ensure that the carding degree is relatively stable, i.e. H. the number of individual fibers exposed to the action of the needle teeth in a unit of time remains relatively stable. Modern cards increase performance through the three aspects of increasing the working arc length of the cylinder, the working width of the cylinder and the working speed of the cylinder. The main reason is to ensure the carding grade of the card is relatively stable while increasing the leistung.
The fiber carding effect has a direct impact on the yarn quality. Therefore, carding technology is the core technology in textile engineering. Strengthening carding technology research is a key element to stabilize and improve yarn quality.
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