Yarn quality can not be improved without technical means

In the past two decades, the quality of spinning yarns has advanced by leaps and bounds, and the demand for yarn quality has also been continuously improved. The pursuit of zero-defect, non-defective production and continuous improvement of the product's inherent and appearance quality is a combination of high-quality and high-efficiency production methods pursued by modern companies. Not only does the yarn require a high level of intrinsic and appearance quality, but it also has to meet the following Efficient weaving production. For example, the production mode of “light extinguishing production and weaving continuous head” puts a very high demand on yarn quality.

On the one hand, the improvement of cotton quality provides the conditions for the improvement of the yarn quality level. On the other hand, the improvement of equipment technology and the quality of key equipment provide guarantees for the improvement of spinning quality level. According to reports, in the past, CJ14.6tex's irregularities of less than 14% can be said to be the industry's advanced level, and the current 11% is already a normal level, and the high level has reached less than 10%.

Today, widely used sensing technologies such as optics, motors, electricity, pneumatics, and hydraulics, as well as frequency conversion technologies, have promoted the development of spinning technology in automation, intelligence, and continuity. This has not only improved productivity and labor productivity, but also improved the quality of spinning technology. The modernization, systematic and scientific management methods have created conditions and are the inevitable trend of the development of textile production quality management.

Comprehensive inspection to achieve full controllable

According to Dai Jun, deputy general manager of Jiangsu Yueda Textile Group, in recent years, there has been a fundamental change in the standards for judging yarn quality. Users are concerned about the quality of indicators on the one hand, and are more concerned with the stability and quality of physical quality and quality on the other hand. consistency. Ni Shimin, a senior engineer at Zhejiang Shuangke 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 stable quality and promote quality stability on the basis of quality improvement. Quality is more important after quality improvement, and it is more difficult for products to achieve zero defects.

Therefore, Xu Wei, general manager of Wuxi Qingfeng Co., Ltd. believes that single spindle control, on-line inspection, simulation of finished products, pre-warning control and best quality have become the development direction of spinning quality control technology. The use of advanced testing equipment and control methods to improve on the basis of the traditional control to meet the quality requirements of high-grade yarn in modern spinning production.   

In order to meet the requirements of users, in recent years, Yueda Textile has explored how to make use of the functions of modern testing equipment. It integrates offline, online, expert system and other detection methods into the quality management system to realize the use of off-line inspection to control the quality and control of spinning quality. Fluctuations, the use of online technology to reduce the quality of weak links, the use of expert systems for quality control of the new system of spinning quality control. With the help of advanced offline inspection instrument functions, the state of the process equipment is optimized and the quality level is improved. Including the use of HVI to achieve scientific distribution of cotton; the use of AFIS, the establishment of semi-manufactured process quality control mechanism; improve Uster UT4, UTJ4 on the quality of yarn monitoring, improve the quality of yarn quality fluctuations.

Use online inspection technology to find quality weaker loops to improve the stability and consistency of quality. With the development of textile production in the direction of automation and intelligence, traditional off-line inspection cannot meet the needs of modern high-speed production. The amount of off-line inspection accounts for only about one ten-thousandth of the total product, and the quality level of inspection cannot accurately reflect the level of physical quality. Application of online monitoring technology has become the trend of modern textile development. The on-line inspection carries out 100% comprehensive inspection of the product. Through inspection, adjustment, monitoring, and alarming, it is possible to eliminate defective or defective products in the production process. On-line inspection also has functions such as quality analysis, statistics, product evaluation, etc. It can effectively combine detection, analysis and optimization production, and provide guarantee for automation of production and quality control. On-line testing has certain advantages in saving production costs. The combination of off-line and on-line technologies can improve the quality of yarns. The use of expert systems to achieve quality control and optimization, improve the overall quality management level.

Yu Jianyong, deputy head of Donghua University, said that the introduction of yarn quality inspection technology into textile processes can improve quality control and increase production efficiency. During the “Eleventh Five-Year Plan” period, some major spinning equipment manufacturers have equipped their main spinning equipment with testing devices. However, the majority of spinning companies consider a small amount of investment funds and do not have many options. Spinning companies that establish ERP management systems Even more rare. The promotion of fully automated, informatized detection and monitoring technologies for the production of spinning processes is conducive to the improvement of labor productivity and, more importantly, to the improvement of yarn quality and production efficiency. The current consideration is how to adapt to the existing equipment process ports, collect production site's operating data in real time, and form a production management system through networking. At the same time, it is connected with the WRP system.

Technical means help improve quality

To achieve full control in the spinning process, on the basis of traditional quality control, quality control measures should be strengthened from the aspects of raw cotton, semi-finished products, yarn formation, and winding, and advanced testing technologies in all sectors must be inseparable.

Computer matching technology has gone through decades of history and is still facing perfect promotion. On the one hand, because cotton has a wide range of sources and varies in quality, the company's respective product strategies are different. Computer-to-machine cotton is actually a collection and storage of raw cotton data. On the other hand, technological means have also been improved. The main problem in the current promotion process is that the information of the raw materials itself is not comprehensive in the acquisition, the quality variation of the manufacturers in use is relatively large, and the cotton bales are also mutated during processing, and the product range is wide. The implementation of computerized cotton is mainly to obtain complete cotton basic data, and then establish models to improve the precision of cotton blending.

High-precision heterosexual fiber identification clearing technology is also a key technology. According to Yu Jianyong, heterosexual fibers are mainly controlled at the raw material end and the winding end. After more than ten years of development, this technology has been rapidly improved, but it is still a problem to completely replace labor. The key to this technology lies in the application of a more accurate identification model and device for heterosexual fibers, real-time detection of cotton flow, key equipment such as open-clean cotton production lines, feeding parts of carding machines, and electronic yarn clearers on automatic winders. The removal of foreign fibers was performed. The workload of enterprises picking up "three wires" is very large. Combining machines and labor will improve efficiency. As a new technology approach, heterosexual fiber identification clearing technology can significantly reduce the labor intensity, but for high-quality products, there are still difficulties in relying on machines to identify the opposite fiber. 

In the textile product quality inspection process, all fabric inspection methods are basically adopted for the detection of fabrics, but for yarn quality inspection, because most of the inspections use destructive testing, only random sampling inspections can be used. Compared with the weaving project, the spinning unit has more spinning spindles than the weaving project. When randomly sampling and testing, it is very likely that some quality defective spindles will not be able to collect samples for a long time to detect, and the subsample level The average quality of the yarns on behalf of the overall level does not completely determine the quality of the fabric. In a group of cotton yarns that are not inferior to the overall level, the defectives of individual packages affect the quality and practical quality of the entire fabric. Accelerating the development of on-line inspection technology, it is the direction of modern spinning production to strengthen the quality control of spinning production process, improve and perfect the defects of traditional yarn quality inspection methods, and improve the quality level of textiles.

Many processes in spinning engineering have used online detection and automatic adjustment and automatic detection technologies earlier. Such as the cleaning process automatically detects the height of cotton bales, automatic detection and control of cotton box storage capacity; carding process automatic leveling system and on-line detection of nep, impurity function; the online process of the inspection process and auto-leveling system; roving The on-line monitoring system of machine spinning tension, the automatic detection of broken ends in the spinning process, and the electronic clearing and production monitoring functions of the winding process have all successfully applied the on-line inspection technology. The combination of on-line inspection and auto-leveling has realized the closed loop of modern spinning production testing and control. The combination of merging and leveling techniques improves the uneven lengths of different segments, such as long and short slivers. The leveling technique can also effectively eliminate jointed waves, drafting waves and mechanical waves.

Xu Wei proposed that modern spinning production should not only have the instrument to detect various yarn performance indicators, but also must pursue the practical quality effect of later products, such as the simulation of blackboard and fabric effects. Many well-known knitting factories in the world perform knitwear weaving and dyeing tests on yarns, dyeing and bleaching tests on yarns, whitening and dead white cotton, and other indicators. Dyed and bleached yarns are inspected for quality of dry, fine and coarse yarns and foreign fibers mixed in. Another example is a lot of yarn-dyed factories, in addition to the use of equipment and blackboard inspection, but also yarn weaving inspection, observe the dry noodles, neps, thick sections and other quality.

In addition, in the modern spinning production system, the machine speed is faster and faster, the number of machines is getting smaller, and the loss of quality defects is more easily reflected. Therefore, it is more important for the pre-control of each process. At the same time, from the adjustment of the raw materials in the spinning system, it is necessary to check the degree of quality control from the system, and to control the quality of the spinning production through the influence of various performance indicators of the raw materials on the yarn quality.