The spinning system is a multi-step, multi-process, streamlined operation process, so there are many factors that affect quality. Raw materials, process design, equipment status, special equipment, and employee operating skills will all have different impacts on product quality. Poor control of any process or link in the production process will affect the final product quality.
01 Factors affecting yarn quality
The five basic management of spinning enterprises: people, machines, materials, methods and environment are all important factors that affect product quality. For example, the physical properties of raw materials, the quality of equipment maintenance, process design and process installation, application and periodic replacement of parts and equipment, and test analysis and control levels, etc.
02 Analysis of causes affecting yarn quality
2.1 The impact of the main indicators of raw materials on yarn production
The short staple ratio, fineness, length of raw materials and their neatness, maturity, impurity content and other indicators, All affect the distribution of fibers within the yarn cross section, thus affecting the yarn quality.
(1) The lint content in the cotton blend is high, which has a greater impact on the evenness of the yarn. During the drafting process, short pile is difficult to be effectively controlled by the drafting mechanism, and floating fibers are easily formed. The short staple rate in the yarn determines the number of floating fibers in the drafting zone, and the number of floating fibers in the drafting zone determines the quality of the yarn to a large extent.
Therefore, it is necessary to effectively control the short lint content of the raw materials. The short lint rate control range: Generally, the short lint rate in raw cotton is controlled below 14%. The two processes of blowing and carding increase The rate must also be strictly controlled below 1%. Experience shows that for every 2.5% increase in the short staple rate in the combed sliver of fine yarn, the CV% value of the finished product will increase by about 1%.
Compared with carded yarn, combed yarn has the characteristics of “even evenness, high strength, small knots, less hairiness, and good gloss”. The reason is that the short staple rate is different. Therefore, it is necessary to strictly control the short staple rate of raw materials and the growth of short staple during the production process.
(2) Fiber fineness directly affects the evenness and thick details of the yarn, and is related to the strength and strength of the yarn. Indicators such as knotting and miscellaneousness are also closely related. Under normal conditions of maturity, when spinning raw materials with finer fineness, the number of fibers distributed in the yarn cross-section is relatively large, and the impact of a single fiber on the overall evenness of the yarn is relatively small, and Due to the large number of fibers in the yarn cross section, it is beneficial to the uniform distribution of fibers.
If the fiber is too thick, the cross-section number of the yarn will be reduced, and the cohesion of the fibers in the yarn will be poor, resulting in a decrease in strength, poor evenness, and an increase in breakage during the spinning process. But if the fiber is too fine, the neps will rise, so it is better to control it appropriately.
Spinning raw materials with poor fineness uniformity will affect the uniformity of fiber distribution within the yarn cross section due to the large difference in fiber thickness. At the same time, the rigidity of the fibers will also be different. , affecting the stability of the drafting force in the drafting zone. Therefore, yarn spun from raw materials with poor fineness uniformity will have poor product quality.
(3) Different fiber lengths affect the evenness, strength and other indicators of the yarn. In the floating zone, the length is certain. In this case, the slow running time of long fibers during the drafting process of spinning is longer than that of short fibers. The fiber speed change points are relatively concentrated and forward, and the yarn quality is good, and vice versa.
When spinning raw materials with poor length uniformity, due to the large difference in fiber length during the drafting process, fibers with different lengths are affected by the drafting mechanism in the drafting zone. The control time is different. Fibers with longer lengths are controlled for a longer time, and fibers with shorter lengths are controlled for a shorter time. Therefore, fibers with different lengths will have differences in the position of the speed change point under the action of drafting force, thus Deterioration of yarn quality.
(4) Fiber with moderate maturity, good surface properties, high strength, strong resistance to hitting and tearing , highly conducive to loosening, carding and removing impurities. During the opening, carding and drafting processes, fiber fatigue is reduced and damage is reduced; fibers with moderate maturity have more curls and good cohesion between fibers, which is conducive to the effective control of fibers by the drafting mechanism. The drafting force fluctuation is relatively small, which is beneficial to improving the yarn quality.
(5) The processing quality is poor, contains many neps, and has a high impurity rate (especially those containing materials that are difficult to remove) When spinning raw materials with a lot of fine impurities), if the impurities cannot be removed in time during the carding process, during the drafting process, because the fibers forming neps are entangled with each other, the movement and speed change will affect each other, and the normal movement and speed change of the fiber will be affected. Restricted, the drafting force fluctuates irregularly along with the running process of neps, thereby increasing the probability of yarn defects; and the presence of impurities in the yarn sliver will cause uneven fiber distribution and structure within short yarn segments. , thus affecting the yarn quality.
Therefore, cotton distribution work is very important. The performance of raw materials has a huge impact on the improvement of yarn quality. In line with the principle of saving costs and stabilizing quality, we strive to achieve Reasonable combination.
2.2 The impact of process design and machine installation on yarn quality
During the drafting process, the fibers are separated into single fibers and maintained in a straight and parallel state. This is an important condition for stabilizing the drafting force and ensuring the normal operation and speed change of the fibers. Therefore, in order to improve the quality of the yarn, it is necessary to It is necessary to rationally design opening and combing.>
(3) Establish and continuously improve a long-term mechanism for on-site management
On-site management must be institutionalized, normalized and standardized to maintain its perseverance and Continued stability. Therefore, on-site management should aim at specialization, standardization, humanism and long-term, so that on-site management can transform from disorderly management to orderly management, and realize the transformation from surprise management to routine management, and from extensive management to refined management. change.
(4) We must conscientiously implement the inspection and assessment of the on-site management system
On the basis of improving the on-site management and assessment system, we must The focus of the work is on promoting the implementation of on-site management work systems through strengthening inspections and assessments, so that the company’s on-site management can achieve “clear goals, implementation of tasks, implementation of personnel, implementation of time, implementation of responsibilities and implementation of assessment”.
(1 ) Spinning quality management is a systematic work, which requires research and analysis from multiple aspects, grasping the key links, and focusing on controlling various quality index requirements in each process.
(2) In quality management work, we must dare to innovate, observe, think, and do things frequently, and develop a strict, meticulous, and serious work style.