Causes and solutions of possible problems in the production process of yarn-dyed fabrics
Weaving defects in the warp or weft direction appear regularly or irregularly on the fabric.
Main reasons: ① The strength of the yarn used is not enough. ② Poor sizing of the yarn (light or heavy sizing). ③ Defective weaving equipment (if the weaving equipment is faulty, it will cause problems such as yarn breakage). ④ The repair of the grey cloth under the machine is not complete. ⑤ The acceptance of finished products is not careful.
Solution: Strengthen repairs.
Weft oblique/weft arc (including size grid)
For woven fabrics and knitted fabrics, the weft skew/weft arc of 2%, and all fabrics with more than 3% skewness cannot be rated as first-class.
① Poor weaving equipment (if the weaving equipment is faulty, it will cause many shutdowns, resulting in weft skew/weft arc) ② Mainly refers to the weft skew/weft arc caused by poor finishing equipment). ③ Poor finishing (weft skew/weft arc caused by the operator's irresponsibility during finishing).
Solution: Strengthen repair and rearrangement (weft calibration).
When the shrinkage in the warp and weft directions of the fabric is larger than the specified value, it cannot be regarded as a first-class product. Different fabrics will have different ranges.
Main reasons: ① Poor finishing. ② The pre-shrinking equipment is defective.
Solution: Pre-shrunk again (within the specified shrinkage rate) / fabric shrinkage and washing, etc.
The feel does not match the standard
The feel of the finished fabric is inconsistent with that of the standard sample, and there are obvious differences.
Main reasons: ① Poor finishing. ② The raw materials are incorrect. ③ The production process is incorrect.
Unqualified color fastness
The color fastness of fabrics (dyed fabrics and dyed fabrics) cannot meet the requirements
Main reasons: ① Poor dyeing process. ② The dyeing material is defective. ③ Poor finishing. ④ Poor operation. (Especially noticeable when the paint is scratched/painted)
Solution: Re-fixing finishing/reproducing fabrics/re-dyeing (dyed fabrics can)/color repair (paint scraping/paint-dyed fabrics can).
The fabric style cannot be consistent with the standard sample
There is a clear gap between the style of the fabric and the standard sample (slub style/segment dyeing style/thickness, etc.).
Main reasons: ① Incorrect raw material (incorrect slub yarn/incorrect yarn count) ② Incorrect production process (incorrect process of segment dyeing / incorrect arrangement of slub yarn or segment dyed yarn) ③ Incorrect finishing process (when the raw materials and organization are correct, whether the finishing process is correct or not will affect the style of the fabric) Solution: ① Reproduce the fabric ② Refinish.
Causes and solutions of defects in printing and dyeing cloth (dyeing problem)
The wrinkle strips are parallel to each other, and the head and tail are flush.
The wrinkle is large in the middle and pointed at both ends. At the junction of the wrinkle strip and the plane, there is a yarn change tail, which is shaped like a skirt wrinkle. Skirt wrinkles mostly occur on fabrics containing chemical fibers, and are not easily found on the original grey fabrics. Only after printing and dyeing processing will it appear. Main reasons: ①The difference in the properties of the chemical fiber itself or the inconsistency of the high-temperature twist setting temperature in the textile factory, resulting in different shrinkage rates of the weft; ②There are differences in the number or twist of the weft yarn used. Solution: re-cast the original grey fabric production.
The wrinkle strips are connected to the seam head, one or more, with different lengths. Some are at one end of the seam head, and some are at both ends of the seam head. The main reason is the poor sewing head of the fabric feeder. The seam head is not straight, firm, the edges are even, and the stitches are uniform. Solution: cut it together with the seam, and deal with it as a second piece of cloth.
Printing and dyeing wrinkle
Generally, there are not many strips on the cloth surface, usually straight or oblique strips, with different lengths and widths. The wrinkle strips produced before printing and dyeing or during the printing and dyeing process are different from normal, and the color difference of the cloth surface is large;
① The original wrinkle of the semi-finished product before printing and dyeing;
②In the process of printing and dyeing, the mechanical tension and the pressure of the roller are not well adjusted; the parallelism of the guide roller and the drying cylinder is not well controlled;
③ The cleaning of the equipment is not done well.
After printing and dyeing, there are fine dead wrinkles in the middle, deep and shallow on both sides, straight lines or oblique shapes. Main reasons: ①The mercerizing machine removes the alkali steaming box and the cloth guide roller of the flat washing tank is uneven or stained with yarn ends and alkali scale; ②The tension of the mercerizing machine is improperly adjusted; ③ The direct steam pipe opening of the de-alkali steaming box will greatly impact the fabric and cause wrinkles. Solution: make up.
The exposed part of the printed and dyed fabric is different from the normal color of the cloth. Generally, irregular light-colored files or color bars appear at the folds of the cloth or on both sides of the cloth. Main reasons:
Some printing and dyeing semi-finished products are used for reactive dyes and disperse dyes, and the cloth surface of the in-process product has alkali or is affected by the action of reducing gas in the air, which affects the fixation of the fabric and the dye, and the exposed part produces a light-colored file. Reactive dyes are prone to wind marks.
Solution: make up.
Side color difference, left center right color difference
Printing and dyeing fabric edge or left, middle, and right shades of the same color.
Main reasons: ① The roller or printing pressure of the dye liquor is inconsistent at both ends; ② During pre-baking or hot-melt baking, the temperature and air volume in the middle and on both sides of the cloth are inconsistent, resulting in inconsistent dry and wet left and right or left, middle and right of the cloth; ③ The color-blocking dyes have inconsistent migration performance under the same processing conditions, resulting in changes in color depth or shade. The solution: color correction
Shade edge (color difference in edge)
The color of the cloth edge is darker or lighter than the normal cloth color. Main reasons: ①The edges of the cloth rolls are uneven during jigging; ②When dyeing, the fabric curling causes a shallow edge; ③The side tissue is thick and the amount of fluid carried is large, resulting in a deep side. Solution: color correction, avoid chromatic aberration cropping.
Along the warp direction of the cloth surface, there are strip-shaped or rain-shaped defects with wide width, irregular shape and different shades. Stripes are divided into grey cloth strips and dyed strips. The position of the head and tail of the billet remains unchanged, but the seam head is similar in color on both sides. The dyed strips pass through the seam, and the two sides are different in shade. Main reasons:
① The uniformity of the dyed fiber raw materials and the fabric structure is poor, resulting in dyeing stripes;
② There is a gap in the selected wool flame to cause singeing stripes;
③ When the material is mercerized, the alkali and alkali removal are uneven, and the color absorption of the cloth surface is uneven, resulting in dyeing streaks;
④The uneven wind at the air outlet causes regular and regular flowers
⑤The post-drying is sharp and uneven, and the dye migration causes streaks
The solution: color correction.
On the dyed fabric, there are uneven or neat shades of color along the weft direction. Main reasons: ①The operation of the weaving machine is poor or the beating-up device of the loom is not good, resulting in the weft density or thin or dense, and the color after dyeing is different from the normal cloth color; ②Dyeing processing stops to produce color files; ③ The over-gauge rate of jigging and pad-coil dyeing is too large, forming a relatively regular dark color; ④The semi-finished product is put on hold for too long, and the folded part is stained to form a color profile; ⑤ After mercerizing, the fabric is not washed and dried in time, and the folds are air-dried to form a color profile after dyeing. The solution: color correction.
Small spots with darker color appear regularly or irregularly on the printed and dyed cloth. The defects are localized and scattered. Usually occurs on light-colored fabrics. Main reasons: ① Poor dissolution when making dyes and colorants; ②The material and color paste are placed for too long to cause agglomeration; ③ The equipment is not clean. The solution: color correction.