As customers’ requirements for yarn quality continue to increase, spinning companies pay more attention to strictly controlling the quality of finished yarn. At present, the harmful defects that affect the quality of cloth mainly include thick places, small details, uneven evenness, flying flowers, neps and abnormal defects. By standardizing production operations and focusing on equipment maintenance, process adjustment and quality control, spinning companies can control yarn defects within normal limits.
01 Reasonably configure process parameters to reduce spinning yarn defects
Reducing yarn defects in semi-finished textile products can effectively reduce the end-break rate of spinning yarns per thousand spindles, and reducing the end-break rate of spinning yarns can increase output, reduce the cost per ton of yarn, and stabilize the quality of the finished yarn. Create favorable conditions for enterprise product competitiveness. We have summarized several specific practices.
In the combing process, optimize the configuration and management of combing elements , you can get a better carding effect. By actively and effectively selecting corresponding technical measures, you can minimize the inlay phenomenon of top combs and cylinders, prevent fibers from entering the cotton web in a bundled structure, and reduce breakage in the next process. Head probability. Regularly check the tension status and wear of the drafting toothed belt and coiling toothed belt, and reasonably adjust the coiling tension, which can reduce the congestion of the coiler and at the same time reduce the probability of overhead breakage of the drawing frame.
Appropriately reducing the nip gap, roller center distance, and back draft ratio of the roving will help reduce the CV value of the spun yarn. However, the tightening of the above-mentioned process will inevitably increase the yarn drafting force and floating fiber control force. The holding force and drafting force, the guiding force and the control force must be developed simultaneously to achieve normal drafting and prevent the roving due to poor craftsmanship. Poor drafting caused by defects in the drafting elements and pressurizing mechanism. Therefore, the optimal combination is sought for the nip gauge of the roving, the roller center distance, the back draft ratio and the total draft ratio.
At the same time, it is necessary to strengthen operation and management work to reduce the impact of factors such as unclean flying particles attached to the yarn sliver and the negative effects of the winding mechanism on the yarn sliver. If these defects are serious, it may This will cause sporadic yarn defects in fine yarns.
02 Improve the drawing process to control the quality of semi-finished products
In the drawing process, the sliver passes through After the combing process, the fiber separation, parallelism, and straightness are good, but the cohesion between the fibers is poor, and they are prone to loosening and hairiness. At the same time, the fibers will no longer have the opportunity to be carded in the subsequent processes. Therefore, the roughening process should reduce the deterioration of the internal structure of the sliver caused by the drafting effect before twisting the sliver, reduce the factors causing defective edge fibers, reduce short lint and fly particles from attaching to the sliver, and reduce the unwinding and rolling of the sliver. It can reduce the friction, rubbing, entanglement and twisting during winding, thereby reducing the neps formed by friction, rubbing, entanglement and twisting.
Reducing the drafting multiple and drafting force can reduce the growth rate of short lint and neps, thereby improving the sliver quality; according to the sliver ration, choose a smaller thick sliver bell mouth The diameter can improve the tightness of the sliver and reduce the probability of local breakage of the sliver when it is fed after the roving frame, thereby improving the sliver dryness and hairiness; according to the sliver ration and sliver barrel capacity, design a reasonable fixed length to avoid sliver capacity Too full will cause excessive squeezing between the top sliver and the bottom coiled sliver, resulting in increased friction, rubbing, and twisting to form neps; it is necessary to control the weight deviation of the cooked sliver and reduce the CV value of the cooked sliver to prevent defects caused by undesirable factors in the drawing process. Long gauze detail.
Therefore, the drawing process should reduce the CV value of cooked strips on the premise of eliminating long details. These are mainly achieved through reasonable design of process routes, configuration of drafting elements and pressurizing mechanisms, and strengthening of operation management and machine cleaning.
In the roving process, the evenness CV value of the roving and the structure of the yarn fibers will affect the evenness CV value of the yarn and frequent yarn defects. The CV value of roving quality will affect the CV value of spun yarn quality, and the yarn defects of roving will affect the occasional yarn defects of spun yarn.
03 Adjust the moisture regain to reduce yarn defects in thick blended yarns
The company responded to user feedback R/C65/3542tex yarn has high yarn defects and many broken ends. By reversing the package and analyzing hundreds of yarn defects, the causes of the above problems were identified. By taking a series of measures, the yarn quality meets user requirements.
By analyzing a certain batch of yarn, it was found that the yarn defects in the pre-spinning process were 56%. After investigation, it was found that the moisture regain of this batch of semi-finished yarn products was small. The standard moisture regain after mixing the sliver was 11.4%, but the actual moisture regain was only 7.5% to 7.8%. We take measures such as viscose fiber pretreatment, disc humidification, and moisturizing during the carding process to achieve a moisture regain rate of 9.5%. The production area of the drawing process is also humidified accordingly, and carbon black rubber rollers are used to prevent the rubber rollers from sucking and wrapping. The actual moisture regain after mixing the slivers reaches more than 8.5%. Through humidification, spinning production is significantly improved and yarn defects are significantly reduced.
The spinning front roller speed of coarse yarn is relatively high, so it is advisable to adopt a large gauge and heavy pressurization process, and adopt a reasonable pressurization gear to ensure drafting. The force is adapted to the holding force and reduces damage to rubber rollers and rubber rings.
Because it is a thick yarn, if the joint parameters are not adjusted properly during the splicing process, a defect will be formed and appear on the fabric surface. Therefore, during the splicing process, yarn tail blowing, yarn tail superposition, air jet splicing and winding are all important.Parameters such as height should be optimized.
By adjusting the splicer and splicing cavity, the drum speed is reduced to 1200 m/min. The main yarn clearing process parameters are short thickness + 130% × 1 cm, long thickness + 30% × 15 cm, slenderness – 40% × 20 cm, and there are about 4 yarn defects after 100,000 meters of rewinding.
Through the implementation of the above measures, the production of this type of yarn has been stable, and the number of yarn defects in hundreds of tubes has been significantly improved, which has been recognized by users. </p
