Technical Means To Improve Yarn Quality

In the past twenty years, the quality of spinning has been advancing rapidly, and the requirements for yarn quality have been improved. The pursuit of zero defect, no defect production, and constantly improving the internal and external quality of products is the mode of production that modern enterprises pursue to combine high quality with high efficiency. It requires not only high inherent and appearance quality, but also high efficiency weaving production. For example, the production mode of "lights out production and weaving is not broken" has raised very high requirements for yarn quality.

On the one hand, the improvement of cotton quality has provided conditions for the improvement of yarn quality level. On the other hand, the improvement of equipment technology level and key equipment quality has provided guarantee for the improvement of spinning quality level. According to the introduction, in the past, the dry irregularity of CJ14.6tex was lower than 14%, which can be said to be the advanced level in the industry. At present, 11% is normal, and the high level has reached 10%.

Today, widely used optical, mechanical, electrical, pneumatic, hydraulic and other sensing technology and frequency conversion technology, promote the spinning technology to automation, intelligent, continuous development direction, not only improve production efficiency and labour Productivity also creates conditions for the modernization, systematization and scientification of quality management means, and is an inevitable trend in the development of textile production quality management.

Comprehensive testing to achieve full control

According to Dai Jun, deputy general manager of Jiangsu Yueda Textile Group, there has been a fundamental change in the yarding of yarns quality level in recent years. Users pay attention to the quality of indicators on the one hand, and pay more attention to the stability and consistency of physical quality and quality on the other hand. Ni Shimin, a senior engineer of Zhejiang double top textile, believes that the connotation of quality control includes quality improvement and quality stability. It is necessary to promote quality improvement on the basis of quality stability and promote quality stability on the basis of quality improvement. After quality improvement, quality stability is more important, and it is more difficult for products to achieve zero defects.

Therefore, Xu Min, general manager of Qingfeng Limited by Share Ltd, Wuxi believes that single spindle control, on-line detection, simulated products, early warning and pre control, and the best quality are the development direction of spinning quality control technology. The advanced testing instruments and control methods are used to improve the traditional control so as to meet the quality requirements of high-grade yarn in modern spinning production.

In order to meet the needs of users, in recent years, Yueda textile has explored how to make use of the functions of modern testing equipment, put offline, online and expert systems into the quality management system, and realize the new system of spinning quality control by using offline technology to control spinning quality level and control quality fluctuation, reduce quality weakness by online technology, and use expert system to conduct quality control. With the help of advanced off-line testing instrument function, the state of equipment is optimized and the quality level is improved. Including making good use of HVI and realizing scientific cotton blending; using AFIS to establish internal control mechanism of semi product process quality; improving quality of yarn by UT4 and UTJ4 Monitor To improve the quality of yarn.

Using online detection technology to find weak quality ring, improve the stability and consistency of quality. With the development of automation and intellectualization of textile production, the traditional off-line inspection has been unable to meet the needs of modern high speed production. Offline inspection accounts for only about 1/10000 of the total product. The quality level of testing can not accurately reflect the quality level of the object. The application of whole process on-line monitoring technology has become the trend of modern textile development. On line inspection, 100% of the products are fully tested. By detecting, adjusting, monitoring, alarming and other means, defective or unqualified products can be eliminated in the production process. Online testing also has the functions of quality analysis, statistics and product evaluation. It can effectively integrate inspection, analysis and optimization production, and provide guarantee for automation in production and quality control. Online detection has certain advantages in saving production costs. Offline and online technology can improve yarn quality. Using expert system to realize quality monitoring and optimization, and improve the overall quality management level.

Yu Jianyong, vice president of Donghua University, said that the introduction of yarn quality testing technology into textile process can improve the quality control level and improve production efficiency. During the "11th Five-Year" period, the main spinning equipments produced by some excellent spinning machinery enterprises were equipped with detection devices. However, most spinning enterprises did not think much of investment funds, and the spinning enterprises that established ERP management system were even more rare. Promotion of spinning process production automation, information technology testing and monitoring technology, is conducive to improving labor productivity, and more importantly, to improve yarn quality and production efficiency can play a positive role. At present, we should consider how to adapt to the existing equipment process port, collect the operation data of the production site immediately, form a production management system by interconnection, and connect with the WRP system at the same time.

Technology helps improve quality

In order to achieve overall control in the spinning process, on the basis of traditional quality control, we should strengthen the means of quality control from raw cotton, semi finished products, yarn and winding.

Computer cotton blending technology has gone through several decades of history, and now it still faces the promotion. On the one hand, because cotton is widely distributed and the quality is different, the strategy of cotton blending is actually collecting and storing raw cotton data. On the other hand, technological means have also been improved. At present, the main problem in the process of popularization is the incomplete information of raw materials in the acquisition process. The quality variation of the manufacturers is relatively large, and the cotton bales are also mutated in processing, which has a wide range of products. The implementation of computer assorting cotton is mainly to obtain complete cotton basic data, and then establish a model to improve the accuracy of cotton blending.

High precision foreign fiber recognition and yarn cleaning technology is also an item. crux Technology. According to Yu Jianyong, heterosexual fibers are mainly controlled at the ends of raw materials and winding ends. After ten years of development, this technology has been promoted rapidly, but there are still some problems to replace artificial labor. The key technology lies in the application of a high accuracy foreign fiber recognition mode and device, real-time detection of cotton flow, and elimination of foreign fibers on key equipment such as opening and cleaning production line, feeding part of carding machine, and electronic clearer on automatic winding machine. There is a lot of work done by enterprises to pick up "three wires". Combining machine with manual will improve efficiency. As a new technical means, the identification of yarn by foreign fibers can greatly reduce the intensity of artificial labor. But for high quality products, there are still difficulties in identifying foreign fibers by machine.

In the process of testing the quality of textile products, the whole inspection method is used in cloth inspection. The quality inspection of yarn is mostly based on destructive test, and random sampling inspection is the only way. Compared to spinning engineering and weaving engineering, its production unit is more spinning spindles. It is very likely that some defective spindles can not be collected for a long time before random sampling inspection, and the average quality of yarns representing the overall level at the sub sample level can not completely determine the quality of the cloth. Often, in a batch of cotton yarn with poor overall quality, some defective products will affect the entire cloth quality and practical quality. Accelerating the development of online detection technology is the direction of modern spinning production to enhance the quality control of spinning production, improve and perfect the traditional yarn quality testing methods, and improve the quality of textiles.

In many processes of spinning engineering, on-line detection and automatic adjustment and automatic detection technology were used earlier. For example, automatic detection of cotton bales height in cotton cleaning process, automatic detection and control of storage capacity of cotton box, self levelling system of carding process, on-line detection of neps and impurities, parallel detection and self levelling system for parallel processes, on-line monitoring system for spinning tension of roving frame, automatic detection of broken ends in spinning process, and electronic cleaning and production monitoring functions in winding process, etc., have successfully applied on-line detection technology. The combination of on-line detection and self levelling has realized the closed-loop detection and control of modern spinning production. The combination of the combination and leveling technology has improved the uneven length of the sliver and short segment, and the smoothing technology can effectively eliminate the joint wave, drafting wave and mechanical wave.

Xu Min pointed out that modern spinning production should not only detect yarn performance indexes, but also pursue practical quality effects such as simulating blackboard and fabric effects. Many famous knitting factories in the world carry out dyeing tests on knitted fabrics, dye dark coloured yarns, test yarn, and kill white cotton stars, and dye and bleach to check yarn quality, such as yarn evenness, fineness and coarse fiber blending. For example, many yarn dyed factories, in addition to using instruments and blackboard inspection, also conduct yarn weaving inspection to observe the quality of cloth sliver, neps and coarse joints.

In addition, in the modern spinning production system, the speed of machine is faster and faster, the number of machines is less and less, and the loss of quality defects is more easily reflected. Therefore, it is more important to pre warn and control each process. At the same time, from the adjustment of raw materials in the spinning system, we need to check the degree of quality control from the system, and control the quality trend of spinning production through the influence of the performance indexes of raw materials on yarn quality.