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. Today, I will introduce some technical measures taken by enterprises to reduce yarn defects, hoping it will be helpful to everyone.
01 Properly configure process parameters to reduce spinning yarn defects
Reducing yarn defects in semi-finished products in the spinning department can It can effectively reduce the end-break rate of spinning yarn per thousand spindles, and reducing the end-break rate of spinning yarn can increase output, reduce the cost of yarn per ton, stabilize the quality of yarn, and create favorable conditions for improving the competitiveness of enterprise products.
In the combing process, the optimized configuration and management of combing and combing elements can achieve better combing effects, and the corresponding technical measures can be actively and effectively selected. , to minimize the inlay problems of top combs and cylinders, prevent fibers from entering the cotton mesh in a bundled structure, and reduce the probability of breakage in the next process. 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 breakage on the draw 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 quality of semi-finished products in the rough process of merging
In merging In the sliver process, after the cotton sliver is combed through the combing process, the fiber separation, parallelism, and straightness are good, but the cohesion between the fibers is poor, and it is easy to become loose and hairy. 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 cotton sliver due to 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 curling 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.
① Reducing the drafting ratio and drafting force can reduce the growth rate of short linters and neps, thereby improving evenness. ② According to the sliver quantity, choosing a smaller outlet bell diameter can improve the tightness of the sliver, reduce the probability of local sliver breakage when feeding after the roving frame, thereby improving sliver dryness and hairiness. ③ According to the sliver quantity and sliver barrel capacity, design a reasonable fixed length to avoid excessive sliver capacity causing excessive squeezing between the top sliver and the coiled sliver bottom plate, resulting in increased friction, rubbing, and twisting to form neps. ④ It is necessary to control the weight deviation of cooked sliver, reduce the CV value of cooked sliver, and prevent long spun yarn details caused by poor factors in the drawing process. 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 yarn
In response to users’ reports that R/C 65/35 42 tex yarn has high yarn defects and many broken ends, our company identified the causes of the above problems by reversing the bobbin and analyzing hundreds of yarn defects. 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 slivers 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 rate after the sliver is mixed 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 pressure process, and adopt a reasonable pressure 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, parameters such as blown yarn tail, yarn tail superposition, air jet splicing, and winding speed must 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 in 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