There are cross roads on the cloth surface, and the spinning mills, weaving mills, dyeing and finishing factories often have different opinions. This article analyzes in detail the various causes of crossroads. It pointed out the direction for clarifying responsibilities and promoting rectification.
01 Spinning mill causes knitted fabrics Factors of rungs
(1) Factors such as origin, batch, color, whiteness, performance, cotton maturity, and micronaire difference of spinning raw materials are affected by raw material quality. Differential effects can cause fabric rungs.
(2) Improper handling of the transition from batch to batch using raw materials, especially when the quality of the raw materials in the succeeding batch is significantly different from the previous batch. The longer the transition time, the longer the input of raw materials in the next batch will increase. The smaller the amount, the less chance of causing fabric rungs, and vice versa.
(3) Uneven mixing of raw materials from different origins, different batches, and different specifications, as well as uneven mixing of raw materials with different components in blended varieties, will cause fabric rungs.
(4) There are generally two ways of mixing raw materials: bag blending and strip blending. Strip blending has a more accurate ratio than bag blending. However, it is necessary to control the weight unevenness of the carded sliver and add a blending process if necessary. This is an important factor in controlling the accuracy of the blending ratio.
(5) When wrapping on the cotton table, pay attention to arranging the bags evenly, cutting them high and filling them evenly. Especially the cotton rolls at the beginning and end are easy to mix unevenly and need to be unrolled for use. The rewinding, stripping and pattern rewinding should be uniform and uniform in the longitudinal direction. The cotton picking beater should catch the cotton more frequently and less frequently to keep the cotton picking machine operation rate above 92%.
(6) When implementing the raw material bale and cotton blending method, in the absence of a multi-silo cotton blending machine, secondary roll formation will be implemented if necessary. The cotton table, middle and lower layers The rolls must be sorted and discharged evenly so that the mixing of different fibers will be more consistent; or a cotton mixing process may be added to pack the pre-mixed raw materials into bags, then put them on the bale grabber and enter the blowroom process.
(7) When implementing the strip-fiber mixing method, the feeding positions of the slivers of different fibers should be fixed and consistent, and the position and structure of the various fibers in the yarn sliver should be kept the same.
(8) When producing multi-component blended varieties with more than 3 types of fibers, a combination of wrapping and strip mixing can be used. Some fibers are selected to be wrapped and blended into strips, and then mixed with another part. Fiber strip mixing ensures that multi-component fibers are mixed evenly.
(9) Produce the same variety, arrange the production of equipment of the same model, maintain process consistency, and avoid differences in cotton yarn quality due to differences in machine models and inconsistent processes. Different types of equipment produce the same type of cotton yarn, and they are mixed and woven on the same circular knitting machine. Due to certain differences in the weight deviation, twist, evenness, hairiness, etc. of the cotton yarn, rungs will appear on the fabric surface, especially on light and thin fabrics.
(10) When the cotton yarn weight deviation exceeds 3.5% or more, the blending ratio difference is greater than 2.5%, and two or more similar yarns are used together, bleaching There will be obvious rungs on the cloth. When the twist difference is more than 4%, cloth surface rungs will also appear on the bleached or dyed cloth.
(11) Various equipment should be clearly distinguished during use, and various finished and semi-finished products should be stored in categories. It is strictly forbidden to mix, mix, and mix to prevent quality accidents of wrong varieties. Resulting fabric rungs.
02 Factors causing knitted fabric rungs in knitting factories
( 1) The cotton yarn is not used in the order of production date, and is used in mixed batches and mixed factories. The pretreatment management is chaotic, the quality control of singeing is poor, and the batch and production date are not marked after singeing.
(2) The operator performed poor operations, arranged and replaced the wrong yarn, threaded the wrong yarn after the end was broken, and did not patch the spandex elastic yarn after it was broken.
(3) The equipment is in poor operating condition and the equipment is in poor debugging condition. The sinker, sinker cam, and knitting needle cam are seriously worn, and the circularity of the needle cylinder is poor.
(4) The package yarn introduction tension is inappropriate, resulting in regular cloth surface rungs, and the circular knitting yarn feeder and yarn feeder are in poor condition, which will cause wide spacing. Fabric covered rails.
(5) During the use of spandex elastic yarn, leakage, broken yarn, reverse yarn, and double yarn occur. The spandex yarn bobbin size of the same circular machine is inconsistent and greatly different, resulting in spandex The thread tension is inconsistent. Regular and widely spaced fabric rungs are closely related to uneven tension of spandex yarn on circular knitting machines.
(6) In the circular knitting production process, there are inconsistencies in the size of yarn loops. Where the loops are large, the fabric density will be high, and vice versa.
(7) The yarn in circular woven fabrics travels horizontally, and longitudinal defects are mostly caused by knitting needles and are generally not directly related to yarn quality.
(8) Depending on the clutch installation position and yarn feeding speed, cloth surface rungs are more likely to appear.
03 Factors causing knitted fabric rungs in dyeing and finishing factories
(1) The dyeing and finishing equipment is in poor condition, the padding roller is eccentric, bent, and has poor roundness, and the printing machine has poor mesh covering, which will cause fabric rungs.
(2) Rungs caused by parking of printing and dyeing, careless operation, long parking time, rollers staying on the cloth surface, imprints of color liquid, rungs after drying on the cloth more obvious.
(3) Direct dyeing without pre-treatment or improper pre-treatment, dyeing time, temperature, pressure, and dyeing material ratio are unreasonable, resulting in uneven color of the cloth surface.
(4) The fibers in the cotton yarn are hygroscopic, the moisture regain is inconsistent, the cloth surface is dry and wet locally, and the coloring is inconsistent, resulting in dyeing rungs of varying shades.
(5) Water evaporates during scouring and there is a lack of water, resulting in contamination.Part of the surface is exposed outside the dye solution, and the coloring is uneven. There is no obvious regularity in the spacing between the rungs of this type of cloth.
(6) During the post-finishing process, improper handling of high-temperature tenters resulted in fabric rungs with tenter marks. Fabric rungs caused by dyeing and finishing factors generally disappear after fading.
(7) When pre-drying after padding the dyeing solution, due to the inconsistent drying rate, dye migration will occur to varying degrees, resulting in inconsistent dye distribution on the surface of the fabric. .
04 Fabric rung analysis method and operation steps
（1 ) The horizontal bars on the fabric surface are mostly not visible on the white gray fabric, and horizontal bars appear on the cloth surface after dyeing. Regular horizontal stripes of a single yarn are generally caused by misaligned yarns; regular wide strips are formed by multiple yarns and are generally caused by fluctuations in raw material quality, mixed batch use of yarns, or inconsistent tension of spandex elastic yarns. cause.
(2) When receiving the crossbar fabric sample, first visually observe the distribution status of the bars, and comprehensively analyze the fabric horizontal pattern through disassembly, instrument testing, chemical dissolution and other methods. The reason for the file. It is necessary to grasp the characteristics of color differences and further analyze the factors causing cloth surface rungs such as mixed batches, twist, yarn count, wrong yarn, uneven elasticity, etc.
(3) Cut a piece of cloth of equal length from the bar cloth. After removing the cloth, measure the yarn at the bar and the normal position in the natural elongation state. Thread length, if there is a difference in yarn length, it may be caused by inconsistent loop size or tension.
(4) After dismantling the fabric, use a spinning test instrument to test the twist, yarn count, evenness, and hairiness of the yarn at the rung, and compare the yarn at the rung with normal conditions. There is no difference in yarn.
(5) For the rung fabric sample containing spandex elastic yarn, according to the FZ/T 01057.4-2007 standard, use the “chemical dissolution method” to dissolve the spandex yarn in the fabric, and then After washing and drying, look at the cloth surface with only yarn fibers left to see whether the characteristics of the rungs are consistent with the characteristics of the original cloth surface. If there are no bars in the pure yarn fabric, the rungs caused by yarn factors can be ruled out.
(6) Similarly, use the “chemical dissolution method” to dissolve the yarn fibers in the fabric, then wash and dry it. From the surface of the cloth where only spandex is left, Check whether the crossbar characteristics are consistent with those of the original fabric surface. If there are equal bars on the pure spandex silk fabric surface, it can be confirmed that the crossbar is caused by the tension problem of the spandex yarn in the knitting factory.
(7) Observe with a fiber fineness meter, slice the longitudinal and transverse sections of the yarn, and analyze whether there are any changes or abnormalities in the fiber structure, fiber state and blending ratio within the yarn. . When slicing, use colored wool as a medium to isolate the fibers. The thickness of the cut section will be more appropriate and the image will be clearer.
(8) Preparation of a solution containing cellulose blended fabrics containing spandex fibers and dissolving the fibers but insoluble spandex fibers: in a beaker First inject 75ml of water, then slowly inject 25ml of 98% concentrated sulfuric acid along the glass rod, and then stir continuously to prepare a 40% sulfuric acid solution.
(9) The method of dissolving cellulose blended fabrics containing spandex fibers but retaining the spandex fibers: Put the elastic fabric sample into a beaker containing 40% dilute sulfuric acid, heat it to 95°C in a water bath, and stir gently with a glass rod. It will take about 30 minutes. Pour out the solution and wear rubber gloves. Clean the spandex silk cloth sample and dry it to check its surface shape. </p
