After the yarn is woven into fabrics, rung defects appear after dyeing, which often causes great losses and is difficult to make up for. The factors that produce fabric rungs involve the entire textile dyeing process. There are many reasons for the spinning process alone, involving spinning raw materials, technology, environment, operations, machinery and other links and processes, such as differences in maturity of raw cotton, weight Unevenness, uneven fiber mixing, insufficient innovation, uneven twist, hairiness differences, etc.
As far as cotton spinning is concerned, the influencing factors that cause cloth surface rungs are as follows:
1. Rungs caused by improper cotton distribution. There is a big difference in the micronaire value of mixed cotton bales, and there is a big difference in the yellow and white color of cotton. The micronaire is low, the fiber is fine, and the maturity is poor. Due to the uneven blending of cotton, the cloth surface is dyed horizontally after the yarn is weaved. Key indicators: the micronaire value of each mark is strictly controlled within 0.5, the yellowness + b value is controlled within the range of 0.5, the difference in micronaire value between rows is ≤0.3, the yellow and white bags are uniformly matched package by package, and the knitting yarn is matched with cotton as much as possible The quantity of cotton supplied is allocated at one time.
2. The cotton mixture is uneven. Improve the operation rate of cotton picking machines and cotton boxes, try to pick cotton as finely as possible, and pick and feed thin cotton frequently to reduce the weight of cotton bundles. Fixed supply and cross-mixing are strictly implemented in each process.
3. Rungs caused by excessive hairiness in the yarn. Spinning yarn travelers should be replaced strictly according to the cycle. The selection of steel rings and travelers should be reasonable. The spinning spindle should be in good condition and the self-winding yarn channel should be smooth and free of burrs.
4. Excessive uneven twist can also cause knitting rungs. Because the twist affects the tightness of the yarn structure, which in turn affects the combination of dye and cellulose during dyeing. Strengthen the training of turners to reduce the occurrence of strong twisting of joints, conduct regular and irregular inspections of the mechanical status of the spinning yarn twisting part, strengthen patrol inspections, and eliminate the spindle belt slipping on the edge of the spindle plate, the spindle belt being loose or the tension is inconsistent , The spindle gall lacks oil or is damaged, the spindle belt has burrs and poor joints, the spindle belt wears the pulley support, etc. The phenomenon of weak yarn twisting is caused.
5. Uneven slivers and the thickness of long segments cause rungs. The combing, drawing, and roving processes reduce the control of hair breakage. The automatic stop of each process must ensure sensitivity and effectiveness. Minimize the difference in yarn tension between large and small rovings, and rationally select fine yarn drafting equipment to improve the evenness of the finished yarn.
Nowadays, the market share of chemical fibers is increasing, and blended fabrics that neutralize the advantages of various raw materials have become the first choice of many customers. However, there are great differences in the spinnability and dyeing properties of different fibers. If the processing is not paid attention to, defects can easily occur. Blended fabrics cause fabric surface rung defects due to yarn problems, and about 70% of them are caused by raw material problems. In particular, raw material mixing problems are the most likely to cause rung defects. Therefore, when making blended yarn, special attention needs to be paid to the initial mixing of raw materials. Here is a brief discussion on how to mix different fibers evenly.
Methods to improve the uniformity of mixing different fibers
Multiple fiber mixing is generally divided into two types: disk mixing and strip mixing
(1) Methods to improve uneven mixing of disks
1. Packing arrangement work
The packing arrangement of raw materials must be carried out strictly according to the packing diagram, and the package positioning shall be implemented. Since the beater of the disc-type cotton picker moves around the central column, the arc length of the central ring is shorter than the arc length of the outer ring. Therefore, when the cotton picker grabs the fibers in the inner ring, it also grabs multiple packages of fibers in the outer ring. That is, the fibers placed in the inner ring can be evenly mixed among the multi-pack fibers in the outer ring. According to this principle, small proportions of raw materials, raw materials with main components and raw materials with longer lengths are placed in the inner ring, which is beneficial to the uniform mixing of the raw materials.
The arrangement position of different fiber packages should be consistent with the arrangement position of the upper plate material. The same kind of raw materials are evenly distributed in the same circle along the circumference of the circle where it is placed. Due to the different tightness of the fiber bundles and the different sizes of fibers captured by the cotton grabber, the fiber bundles with high density must be placed in the inner ring to facilitate the uniformity of the fiber blocks.
The principle of “axial staggering and circumferential dispersion” should be followed when discharging cotton bales. After the cotton bales are arranged, the bales should be low and high so that the heights are even. When using a disc cotton picking machine, it is best to use two machines in parallel. Before the raw materials enter the blowroom workshop for use, packages with large differences in moisture regain of raw materials must be loosened in advance, and humidification or dehumidification measures must be taken to balance the moisture regain and ensure that the moisture regain of raw materials on the machine is basically similar.
2. Premixing work
If the properties and spinnability of two or more fibers are quite different, Large, plate mixing can be used when mixing, but sometimes premixing is required. Premixing is divided into manual premixing and mechanical premixing. Manual mixing is suitable for small production volumes, such as samples of tens of kilograms or hundreds of kilograms. Manual mixing A variety of fibers are torn and pre-mixed; mechanical pre-mixing is suitable for batch production. The two fibers are arranged and packaged in proportion. After pre-opening, the loose fibers are packaged into pieces and then re-packed. The premixing method can make it easier for the two fibers to be fully mixed in the blowroom process, and then through the carding, mixing and drafting and combining of the drawing process, it can ensure that the fibers are evenly mixed in proportion. Taking viscose and nylon blended yarn as an example, nylon is not easy to form into strips independently. The viscose and nylon can be mechanically premixed and packaged through the disc mixing method, and the packaged fibers are then disc mixed to ensure that the fibers are Mixing evenly can also improve spinning quality.
3. Use of back patterns
Producing blended yarns, there are many types of back patterns, and the workshop To set up a specialThere is also a lot of waste back. The mixing process should be chosen to facilitate the management of raw materials in the workshop and the reuse of waste back to reduce costs.
Summary
How to effectively avoid fabric rungs depends on many factors, among which The mixing of ingredients is most important. How the fibers are mixed during the spinning process depends on fiber properties, spinnability, quality requirements, equipment and staffing, blending proportions, and the actual management level of each factory. Specific issues must be dealt with in detail and cannot be generalized. . According to its own characteristics, it is not difficult to manage each equipment and its operation and design a scientific, reasonable and convenient method to mix the fibers evenly and effectively avoid cloth surface rungs.
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