With the advancement of textile technology, the speed of water-jet looms continues to increase, and the weaving efficiency increases significantly. However, as the weaving speed increases, it becomes more difficult to ensure weaving quality. Warp weave is a common weaving defect in polyester water-jet weaving. The causes of its formation are more complex, and are more obvious in light and thin fabrics. The main reasons for the formation of warps in polyester filament fabrics are the quality of raw materials and uneven tension during weaving production. The state of the equipment also has a certain impact. The existence of warp willows seriously affects the quality of fabrics and affects the improvement of economic benefits of enterprises. Therefore, it is of positive significance to explore the causes of warp willow defects in polyester water-jet weaving. On the basis of long-term tracking of the production processes of polyester low-elastic yarn, sizing and weaving, water-jet weaving, dyeing and finishing processing used by Siyang Chemical Fiber Industry Cluster Co., Ltd., the causes and improvement measures of warp willow defects were discussed. In order to provide a reference for eliminating warp willow defects in water-jet weaving.
1 The reason for the occurrence of warp weaving in water-jet weaving
Warp weaving refers to the straight strips that appear wide or narrow upward on the warp surface of the fabric, causing the surface of the fabric to There are color differences after dyeing, and their distribution may be regular or irregular. Warp weaving is a common defect in polyester water-jet weaving with complex causes and difficult to solve. It has a negative impact on the quality and economic benefits of polyester filament fabrics produced by related companies. This article discusses and summarizes the causes of warp defects in polyester fabrics based on long-term tracking of the polyester weaving and products of Siyang Chemical Fiber Industry Cluster Co., Ltd.
1. Raw material quality fluctuation factors
The influencing factors of raw silk on warp willow are relatively complex, mainly reflected in the uneven linear density of the thread and the difference in cross-sectional shape , the number of single fibers inside the multifilament is different, the content of raw material components is different, and the spinning processing conditions are different. Differences in the linear density of raw yarns and fluctuations in CV values will affect the reflective gloss properties of the raw yarns, which will then reflect differences in the gloss of the filaments. Fluctuations in the breaking strength of the original filaments will cause lint and broken filaments due to friction during the contact between the warp filaments and the machine parts; differences in the elongation properties of the original filaments will lead to different elongations of each warp filament and uneven yarn tension; production of original filaments Different temperatures and processes will cause differences in the internal crystallization state of the filament, resulting in an increase in the variation of the boiling water shrinkage of the filament. Uneven shrinkage during the fabric dyeing and finishing process will lead to uneven cloth surfaces; unstable oil content in the filament will cause warp tension fluctuations , The warp wires are prone to entanglement during warping, and friction causes static electricity accumulation during the production process, eventually causing warp defects on the cloth surface.
2. Various production process factors
Warping aspects
A certain tension must be applied to the warp wires during the warping process. To ensure the normal progress of weaving. Differences in fluctuations in warp thread tension will cause inconsistent elongation and deformation of the warp threads, and differences in warp thread refraction. When the processing tension is removed, the elastic deformation and recovery of the warp yarns are different, resulting in differences in the elongation of the warp yarns. This will affect the fabric’s absorption of dye liquor during the dyeing and finishing process, and warp willows will be formed on the cloth surface. The main factors causing warp tension fluctuations: a) Differences in the size of each package on the warping creel during the warping process, unreasonable placement of packages, and unsmooth wire paths will all lead to different unwinding tensions; b) The angle of the warping fan is incorrect. , the friction experienced by the warp threads is different; during the warping process, the number of threads is changed or the fixed-width reed is threaded incorrectly, resulting in uneven warp surface tension; c) The tension compensator of the warping machine is in poor condition, and the warp thread tension difference is too large.
In terms of sizing
The fluctuation of the unwinding tension in the unwinding area of the warp beam during the sizing process, and the elongation of the warp between the sizing roller and the drag roller If it is too large, unstable drying temperature will lead to excessive relaxation and bonding of the warp yarns, surface damage of the sizing roller, fluctuations in vehicle speed and other factors will cause uneven warp yarn tension during the sizing process. There are messy threads, oil stains and other debris on the mesh cover. If the air inlet is not cleaned in time and the air inlet is blocked, causing the hot air flow to be unsmooth, the air inlet volume of the drying room deviates from the set value, and the operator fails to deal with the yarn threading and short ends in time, etc., it may lead to frequent interruptions. Willow was born.
In terms of parallel beams
When FDY is used for the warp of polyester filament fabrics, warp threads are easily produced at the head and tail of the weaving beam, and the water jet cannot pass through. The weaving machine process must be adjusted to eliminate it, which seriously affects the weaving efficiency of the enterprise. Through the author’s long-term follow-up analysis of the weaving of this variety, it was found that the number of doubling beams is related to the occurrence of head and tail warp willow defects, and the structure of the doubling machine frame will also have a certain impact on the head and tail warp willows. The warp wire is passively withdrawn from the doubling machine, and the creel frame relies on the tension sensor to adjust its braking force. Due to the differences in the friction factors between the braking system and the paddle shaft between the various shafts, the tension between the various shafts is different. . At the same time, when the parallel machine is stopped, the tension of each axis of the parallel machine is also inconsistent, which eventually causes warp defects in the fabric.
In terms of weaving
The warp and weft density and organizational structure design of the polyester fabric are unreasonable, and the fabric is too tight and too dense, which will cause warp problems. The probability of willow increases. All will increase the probability of producing warp willow. Among them, the plain weave fabric is the most obvious, the twill weave fabric is the second, and the satin weave fabric is the smallest. In the weaving process, the tension is too high or too low when the warp faces are connected, which will cause the warp tension difference; improper process design such as weaving speed, shedding amount, and curling speed in the weaving process may cause warp willows.
In terms of dyeing and finishing
Desizing of polyester yarn is inevitable and uneven alkali reduction will affect the coloring of the slurry; the surface of the polyester yarn is affected by Damage causes different absorption of dye liquor, resulting in differences in dyeing performance, affecting the uniformity of dyeing, resulting in warp marks on dyed fabrics.Replace it to ensure that the equipment is operating normally. Each brake should be equipped with a tension sensor to monitor the tension in real time and eliminate the impact of the start and stop of each axis on the warp tension fluctuation. The unwinding method is improved, each creel frame is switched to a variable frequency motor, each axis is changed from passive unwinding to active unwinding, and the speed of the doubling machine is synchronously adjusted according to the change in unwinding tension to further reduce the tension difference between the warp threads in each axis.
5. Weaving process
The weaving process must be reasonable, so that the jet water flow is well concentrated and the nozzle direction is accurate to avoid the water jet from contacting the warp. yarn, causing warp yarn tension fluctuations. Reduce the heald density as much as possible. Practice has found that it is more appropriate to control the heald density at 8 to 10 roots/cm. Too high a density will cause too much friction, so the heald density should be reduced as much as possible. Strengthen equipment inspection and maintenance efforts to ensure that the water-jet loom machine is clean and the reed seat is free of slurry blocks. Regular inspections of heald seams and reeds are carried out to solve problems in a timely manner. Strengthen technical training for operators, improve operating skills, and implement an assessment system to improve employees’ sense of responsibility and avoid deterioration in weaving quality caused by human factors.
Our company mainly uses plastic healds, which are easy to swing. Warp defects can easily occur on light and thin fabrics. By increasing the density of heald cards, the healds are prevented from swinging and bending, and the plastic heald eyelets are prevented from blocking the warp wires, causing wide and rapid warps. After weaving on the shaft, raw material problems should be reported back in time and implemented in the previous process to improve the responsibility of the previous process. In view of the color warp that seriously affects quality problems, after each pan head is turned on normally, a 10cm cloth strip is taken for dyeing inspection. If there is any abnormality, it is removed in time to avoid causing losses to the company.
6. Dyeing process
Before dyeing and finishing, the warp yarns need to be completely desized to avoid coloring of the warp yarn sizing; choose a product with good level dyeing properties For dyes, leveling agents should be added appropriately during the dyeing process to ensure that the dye molecules evenly enter into the fibers.
3 Conclusions
Through long-term production practice, we draw conclusions: ensure stable quality of polyester raw materials, strengthen preparation process management, standardize weaving operations and equipment management, etc. , can effectively reduce warp defects on polyester fabrics.
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