Improvement of yarn thread quality is inseparable from technical means(3)

(continued above)

Scientific and technological means help to improve quality of yarn and thread

In order to achieve comprehensive control in spinning process, on the basis of traditional quality control, quality control measures of yarn and thread should be strengthened in raw cotton, semi-finished products, yarn and thread forming and winding, and advanced detection technology in each link is indispensable.

Computer cotton blending technology has gone through decades of history, and is still facing improvement and promotion. On the one hand, because cotton has a wide range of sources, different quality and different product strategies, computer cotton blending is actually the collection and storage of raw cotton data. On the other hand, technological means have been upgraded. At present, the main problems in the process of promotion are the incomplete information of raw materials themselves in the acquisition, the large variation of quality in the use of manufacturers, the variation of cotton bags in the processing, and the wide range of products. Implementing computer cotton blending is mainly to obtain complete basic data of cotton, and then establish a model to improve the accuracy of cotton blending.

High-precision yarn and thread clearing technology for heterosexual fiber recognition is also a key technology. 

According to Yu Jianyong, heterosexual fibers are mainly controlled at the raw material end and winding end. After more than ten years of development, this technology has been improved rapidly, but there are still problems in completely replacing manual work. 

The key of this technology lies in the application of more accurate foreign fibre recognition modes and devices to real-time detection of cotton flow, and the removal of foreign fibers on key equipment such as opening and cleaning production line, feeding part of carding machine and electronic yarn and thread cleaner on automatic winder. The work of picking "three silks" in enterprises is very heavy. The combination of machine and manual will improve the efficiency better. 

As a new technical means, the technology of identifying and clearing foreign fibers can greatly reduce the labor intensity, but for high-quality products, it is still difficult to identify foreign fibers by machine.

In the process of testing the quality of textile products of yarn and thread, the method of full number inspection is basically used for testing the fabrics'surface, while the method of random sampling inspection is only used for yarn and thread quality inspection because most of the tests are destructive tests. 

Compared with weaving engineering, there are more spinning spindles in the production unit of spinning engineering. 

When random sampling inspection is carried out, it is very likely that some spindles with quality defects can not be sampled for a long time to be tested, and the average yarn and thread quality representing the overall level by the level of sample can not completely determine the fabric quality of yarn and thread. 

Often, in a batch of cotton yarns and threads with the same overall level, individual rolled yarns and threads are packed. Secondary products will affect the quality of the whole fabric and practical quality. 

Accelerating the development of on-line detection technology, strengthening the process quality control of spinning production, improving and perfecting the shortcomings of traditional yarn quality detection methods and improving the quality level of textiles are the direction of modern spinning production.

In many processes of spinning engineering, on-line detection, automatic adjustment and automatic detection technology were used earlier. 

For example, automatic detection of bale height, automatic detection and control of cotton box storage, automatic leveling system of carding process and on-line detection of neps and impurities, on-line detection and self-leveling system of drawing process, on-line monitoring system of spinning tension of roving frame, automatic detection of broken ends of spinning process and electronic cleaning and production monitoring function of winding process have been successfully applied. 

On-line detection technology. The combination of on-line detection and self-leveling realizes the closed-loop detection and control of modern spinning production. 

The combination of coalescence and leveling technology improves the uneven length of different segments, such as strip length and short segment. The leveling technology can also effectively eliminate joint wave, stretch wave and mechanical wave.

It should be pointed out that in modern spinning production, not only the performance of yarns and thread should be measured by instruments, but also the practical quality effects of back products should be pursued, such as simulating blackboard and fabric effects. Many well-known knitting factories in the world carry out dyeing and dyeing tests on knitted fabrics, dyeing dark to test yarn crossing, dead cotton white star and other indicators, dyeing and bleaching to test yarn and thread quality, such as yarn evenness, fineness and foreign fiber blending. For example, in many dyeing factories, besides instrument and blackboard inspection, yarn weaving inspection is also carried out to observe the quality of noodles, neps and pitches.

In addition, in the modern spinning production system, the machine speed is faster and faster, the number of machines is less and less, the loss of quality defects is more easily reflected. Therefore, early warning and pre-control of each process is more important. At the same time, in order to adjust the raw materials in the spinning system of yarn and thread, it is necessary to check the degree of quality control from the system, and to pre-control the quality trend of spinning production through the influence of each performance index of raw materials on yarn and thread quality.