With the continuous improvement of customers' requirements for yarn quality, spinning companies have paid more attention to strictly controlling the yarn quality. At present, the harmful defects affecting the quality of the cloth mainly include thick knots, details, unevenness, flying, neps and abnormal defects. By standardizing production operations, focusing on equipment maintenance, process adjustment and quality control, spinning companies can control yarn defects within the normal range.
The next yarn exhibition will introduce you.
1. Reasonably configure process parameters to reduce spinning yarn defects
Reduce the yarn defects in the semi-finished fabrics can effectively reduce the end break rate of the spun yarn, while reducing the end break rate of the spun yarn can increase the output, reduce the cost per ton of yarn, stabilize the yarn quality, and create favorable conditions for improving the competitiveness of the company's products. We have summarized several specific practices.
In the combing process, do a good job of optimizing the configuration and management of the combing carding elements, to obtain a good carding effect. By actively and effectively selecting the corresponding technical measures, try to reduce the inlays of the top comb and cylinder. This phenomenon prevents the fibers from entering the cotton web in a bundle structure and reduces the chance of end breaks in the next process. Regularly check the tension state and abrasion of the draft toothed belt and the coiled toothed belt. Reasonably adjust the tension of the coiled ring, while reducing the congestion of the coiler, it can also reduce the probability of broken overhead of the draw frame.
Appropriately reducing the jaw spacing, roller center distance, and draft ratio of the back of the roving will help reduce the CV value of the fine yarn. However, the tightening of the above process will inevitably increase the sliver drafting force and the planktonic fiber control force. The holding force and the drafting force, the guiding force and the control force must be developed simultaneously to draw normally, to prevent the poor roving process, Poor drafting caused by defects in the drafting element and the pressurizing mechanism. Therefore, the jaw spacing of the roving, the center distance of the rollers, the draft multiple in the rear zone, and the total draft multiple seek an optimal combination.
At the same time, it is necessary to strengthen the operation and management to reduce the influence of factors such as the unclean flying of the machine on the sliver and the adverse effect of the winding mechanism on the sliver. If these defects are more serious, sporadic yarn defects may occur.
2. Perfect and rough process control of semi-finished product quality
In the drawing process, after the sliver is combed through the combing process, the fiber separation, parallelism, and straightness are good, but the cohesion between the fibers is poor, and it is easy to loosen and hair, and the fiber will not be in the subsequent process. There is a chance to comb. Therefore, the thickening process should reduce the deterioration of the internal structure of the sliver before the twisting of the sliver, reduce the factors that cause the edge fiber to be defective, reduce the lint and flying flowers attached to the sliver, and reduce the sliver unwinding and curling. Friction, kneading, entanglement and twisting during winding, thereby reducing the neps formed by friction, rubbing, entanglement and twisting.
Reduce the draft multiple and draft force can reduce the growth rate of lint and neps, thus improving the dryness;
According to the sliver quantification, choosing a smaller diameter of the sliver bell mouth can improve the tightness of the sliver and reduce the chance of local sliver breakage when the sliver is fed after the roving machine, thereby improving the sliver and hairiness;
According to the sliver quantity and barrel capacity, design a reasonable fixed length to avoid too much sliver capacity and cause excessive squeezing between the top sliver and the sliver chassis to increase friction, kneading and twisting to form neps;
It is necessary to control the deviation of the weight of the sliver, reduce the CV value of the sliver, and prevent the details of the yarn length caused by the poor drawing process.
Therefore, the drawing process should reduce the CV value of cooked slivers on the premise of eliminating long details. These are mainly achieved through reasonable design of the process route, configuration of drafting elements and pressurization mechanisms, strengthening of operation management and machine cleanliness.
In the roving process, the CV value of the roving sliver and the structure of the sliver fiber will affect the CV value of the sliver and the frequently occurring yarn defects. The roving quality CV value will affect the spun yarn quality CV value, and roving yarn defects will affect sporadic yarn defects.
3. Adjust the low-wet blended yarn defect
Aiming at the problems that users report that R / C65 / 3542tex yarn has high yarn defects and many end breaks, we have found out the reasons for the above problems by rewinding the package and analyzing hundred tube yarn defects. By adopting a series of measures, the yarn quality has reached the user requirements.
Analysis of a certain batch of yarn found that the yarn defect in the pre-spinning process was 56%. After investigation, it was found that the moisture regain of this batch of yarn semi-finished products was small. The standard moisture regain was 11.4% after the slivers were mixed, but the actual moisture resurgence was only 7.5% to 7.8%. We have adopted measures such as pretreatment of viscose fibers, humidification of discs, and moisturization during the carding process, so that the moisture regain of the card can reach 9.5%. The production area of the drawing process is also humidified correspondingly, and carbon black rubber rollers are used to prevent the rubber rollers from sucking and entanglement. After the slivers are mixed, the actual moisture regain is more than 8.5%. Through humidification, the spinning production is significantly improved, and yarn defects are also significantly reduced.
The spun yarn has a high front roller speed for spinning coarse yarns. It is advisable to adopt a large-gap, heavy pressurization process and a reasonable pressurization gear to ensure that the drafting force is compatible with the gripping force and reduce the rubber roller. Damage caused by rubber ring.
Because it is a coarse yarn, if the joint parameters are not adjusted properly during splicing, a defect will be formed and it will appear on the cloth surface. Therefore, in the splicing process, parameters such as blown yarn tail, yarn tail superposition, air-jet splicing, and winding speed must be optimized. By adjusting the splicer and the splicer cavity, the speed of the trough can be reduced to 1200 m / min. The main yarn clearing process parameters are short thick + 130% × 1 cm, long thick + 30% × 15 cm, and long thin-40% × 20 Cm, up to 100,000 meters of yarn defects reached about four.
Through the implementation of the above measures, the production of this type of yarn is stable, and the defect of 100-tube yarn is significantly improved, which has been recognized by users.
Source: Chemical Fiber Headlines
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There are two main weaving methods, knitted and woven. Knitting refers to weaving in the form of loops and loops. The most intuitive feature of the fabric is that you cannot see the warp and weft directions of the fabric intersect perpendicularly, but one by one loop, and the knit fabric has a soft hand and a strong drape. Weaving means that the warp and weft of the fabric (that is, vertical and horizontal) are formed by vertical interweaving; woven fabrics are divided into shuttle woven and shuttleless woven, the difference is whether there is a Weft insertion effect of shuttle.
knitting
The process of using knitting needles to form loops of various raw materials and varieties of yarns, and then connecting them through knitting to form knitted fabrics. The knitted material is soft, has good wrinkle resistance and breath ability, and has large extensibility and elasticity, and is comfortable to wear. In addition to knitting and decoration, knitted products can also be used in the fields of industry and agriculture, as well as medical and health and national defense. There are two types of knitting: hand knitting and machine knitting. Hand-knitting uses stick needles. It has a long history, exquisite craftsmanship, and flexible flower shapes. It has been widely spread and developed in folk.
Woven
The process of forming woven fabric with yarn as warp and weft according to various fabric structures. It usually consists of three parts: preparation before weaving, weaving and weaving of the warp yarn into a weaving shaft and weft yarn into a shuttlecock (or package). Weaving is an important part of the production of the textile industry. It can be divided into cotton, wool, silk and linen according to the type of raw materials used. The variety and use of woven fabrics are extremely wide (see textiles). According to different requirements, select the appropriate yarn raw materials and appropriate fabric organization.
The difference between weaving and knitting
1. The fabric structure is different. Weaving can control different weft yarns passing through the warp yarns to form different fabric patterns and structures. Knitted fabric also has a corresponding organization structure, including the basic organization: flat needle organization, rib organization, and double back organization.
2. The organization of change is different. Weaving is formed by the combination of the above three basic organizational changes. In addition to the three basic organization changes of knitting, there are plain needle structure and rib structure as its basic changes.
3. The basic unit of fabric organization is different. The loop of a knitted fabric is the smallest basic unit of the knitted fabric, and the loop is composed of a trunk curve and an extension line in a spatial curve. Each point of intersection between the warp and weft of a woven fabric is called a weaving point, and is the smallest basic unit of a woven fabric.
4. Complex Chengdu is different. Weaving has double tissues (multiple woven into thick flannelettes, cotton fleece blankets, etc.), fluffed tissues (such as corduroy fabrics), towel tissues (towel fabrics), double-layer tissues (towel fabrics), and leno tissues. And knitting also has double back and so on. In general, Chengdu is more complex than weaving.
5. Features and uses are different. Woven fabrics are suitable for various printing and dyeing finishing methods. Generally speaking, printed and jacquard patterns are finer than knitted, knitted and felt fabrics. After changing the structure and improving the dimensional stability of knitted fabrics, it can also be used as underwear, outerwear, socks, gloves, hats, sheets, bedspreads, curtains, mosquito nets, carpets, lace and other clothing, living and decorative cloths.
The difference between knitted fabrics and woven fabrics
Knitted fabrics and woven fabrics have their own unique characteristics due to the different methods of weaving. In terms of processing technology, cloth surface structure, fabric characteristics, and finished product uses, they have their own unique characteristics. Here are some comparisons.
1. Composition of fabric structure:
(A) Knitted fabric: A yarn is sequentially bent into a loop, and the loops are connected in series to form a fabric. The process of forming a loop of yarn can be performed horizontally or longitudinally. Lateral weaving is called weft knitting and longitudinal weaving Called warp knitted fabric.
(B) Shuttle fabric: It is a fabric made of two or more sets of mutually perpendicular yarns interlaced at a 90-degree angle of warp and weft. The longitudinal yarns are called warp yarns and the transverse yarns are called weft yarns.
2. The basic unit of fabric organization:
(A) Knitted fabric: The loop is the smallest basic unit of knitted fabric, and the loop is composed of loop trunk and extension line in a spatial curve.
(B) Woven fabric: Each point of intersection between warp and weft yarns is called a weaving point and is the smallest basic unit of a woven fabric.
3. Fabric organization characteristics:
(A) Knitted fabric: because the loop is made by the yarn bending in space, and each loop is composed of a yarn, when the knitted fabric is subjected to external tension, such as longitudinal stretching, the bending of the loop changes, and the loop The height of the stitches also increases, while the width of the stitches decreases. If the tension is laterally stretched, the situation is the opposite. The height and width of the stitches can be switched between each other under different tension conditions, so the stretch ability of the knitted fabric is large.
(B) Woven fabric: Because the warp and weft are intertwined, and the bends in a direction perpendicular to the plane of the fabric, the degree of bending is related to the mutual tension between the warp and weft, and the stiffness of the yarn. External tension, such as longitudinal stretching, warp yarn tension increases, bending decreases, while weft yarn bending increases, such as longitudinal stretching non-stop until the warp yarns are fully straightened, while the fabric shrinks laterally. When the woven fabric is stretched laterally by external tension, the tension of the weft yarn increases, the bending decreases, and the warp warp increases, such as the horizontal stretching is continued until the weft yarn is completely straightened, and the fabric shrinks longitudinally. Warp and weft yarns do not change, unlike knitted fabrics.
4. Characteristics of fabric organization:
(A) Knitted fabric: It can be stretched in all directions and has good elasticity. Because the knitted fabric is formed by hole-shaped loops, it has a large air permeability and feels soft.
(B) Woven fabric: Due to the warp fabric warp, weft yarn extension and shrinkage have little relationship and no change occurs, so the fabric is generally tight and stiff.
5. The physical and mechanical properties of the fabric:
(A) Knitted fabric: the physical and mechanical properties of the fabric, including longitudinal density, transverse density, square meter weight, elongation, elasticity, breaking strength, abrasion resistance, curling, thickness, release, shrinkage, covering And bulk density.
(B) Woven fabric: The physical and mechanical properties of the woven fabric, including the yarn density of warp and weft yarns, selvedge, front and back, forward and reverse wool direction, and fabric coverage.
Source:MAIGOO
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