Technology | How to reduce yarn defects in the spinning process

First, yarn classification

According to the probability of occurrence of yarn defects, it can be divided into permanent gauze and sporadic gauze.

Permanent gauze is usually nep, short thick and details. Regular gauze defects are short, small, small and numerous, generally have little effect on the processing and fabrics of the post-process, and are usually not easily removed. However, the number of gauze defects must also be controlled for high-grade fabrics.

Sporadic yarn defects usually occur suddenly, cover a wide area, and cause greater harm. They are also called sudden yarn defects. Sporadic yarn defects generally appear to be thick and slender, and most of these yarn defects are caused by poor production management, poor operation, incomplete equipment, poor operation of special parts, and unreasonable process design. This type of yarn is large and small, but it has a significant effect on the downstream processes and fabric quality and must be removed. Sporadic yarn defects common in spinning companies mainly include short thick sections, nep impurities, increased hairiness, and defects in stems. In the production process, sporadic yarn defects often appear suddenly with the change of some influencing factors, and quickly spread to some varieties or regions on the production line, causing some large fluctuations in certain quality indicators. The number of sporadic yarn defects is not very large as a whole, but the damage is large, which often results in the quality of yarns and fabrics , which affects the efficiency of the loom. Therefore, it is one of the important tasks of quality control in the spinning production process.

Second, measures to reduce sudden gauze defects

1. Reasonably configure process parameters to improve the intrinsic quality of semi-finished products

Reducing the semi-finished yarn defect in the spinning department can effectively reduce the yarn breakage rate when thousands of spindles are used, thus increasing the output, stabilizing the yarn quality, reducing the cost per ton yarn, and creating favorable conditions for improving the competitiveness of the company's products.

Carding process: regularly check the tension state and wear condition of the draft toothed belt and the ring toothed belt, and reasonably adjust the tension of the coil, so as to reduce the probability of breaking the head of the guide bar at the same time as reducing the jamming of the coiler. For example, when the spinning and carding fine-spinning production line of the air spinning workshop is changed to the coarse branch production line, the interrelation between the ration, speed, and tension of the cotton web is adjusted through the process optimization, which reduces the number of breaks and joints of the carding and improves the carding production efficiency. This not only reduces the labor intensity of workers, but also improves the quality of semi-finished products.

And rough process: The parallel draw, roving jaw distance, roller center distance, rear zone draft multiple of appropriate reduction will help to reduce the dry yarn CV% value, but the precondition is the holding force and the drawing force, guide The force and the control force are synchronously developed and normal drafting is performed to prevent poor draft due to defects in the roving process, the drafting element and the pressurizing mechanism. Therefore, the optimum combination of the drawbar, roving jaw gap, roller center distance, rear zone draft multiple and total draft needs to be sought. Through process optimization, the CV% of the ring spinning TD03 drawbars was improved. After a comparative test, the draft in the back zone was changed from 1.42 times to 1.35 times, and the CV% of the sliver was reduced from 3.85% to 2.59%. The sliver dry CV%.

Spinning process: The users of Siro spinning blended products are reported to have irregularities, rough knots, and nep, and propose improvement measures. First adjust the process parameters. When the spindle speed is reduced to less than 14,000 rpm when the life is not good, the traveler must be aggravated by using No. 1 and change from the original 4/0 to 3/0. Otherwise, the yarn is very soft and easy to detach from the ring. If the life is normal, the speed can be increased to more than 14000rpm, then the original 4/0 traveller can be used. At the same time, we also observed that the loss of the single fiber at the front roller is relatively high, and it seems that the twist does not pass. It is very easy to cause a break, and the roller breaks around the roller. In order to solve this problem, we increased the spun yarn setting (from 720 to 760), and also increased the spindle speed (the original 13,000 was changed to 14200 rpm), and the line speed was changed from 18 meters/minute to 18.68 meters/minute. The decapitation was reduced, and the output was also higher than the original. The spindle speed can be further mentioned above 14500 rpm and finally reach 15000 rpm (line speed 19.7 m/min), but the precondition for speed increase is that the roller has good resistance to winding and does not go around the cotton. Only to speed up.

2, strengthen the operation and operation management

To produce a good product, the operator's operating skills and quality of work are the key. Therefore, the focus of operation management is to grasp operation management and grasp training.

First of all, do a good job of clean and tidy work to reduce the impact on the quality of the sliver due to the machine table is not clean, fly attached to the sliver, the winding mechanism, etc. If the machine is badly cleaned, it may produce sporadic yarn defects. When we strengthen the management of cleanliness and cleanliness, we must seize the work in two aspects: on the one hand, strict management of cleanliness; some varieties should break the traditional method and implement a circular cleaning method, that is, they should do it in class, always do it, and keep the channel clean. No hanging flowers. On the other hand, we must strengthen the management of cleaning tools, use tools properly, and strictly clean operating methods to eliminate the phenomenon of shooting, playing, smashing, and blowing, and reduce the occurrence of yarn defects. If pure polyester or blended products are made of polyester chemical fiber oil, gauze channels tend to accumulate oil stains that are easily entangled and cause sliveriness. The parallel strips are easy to block the bell mouth and the trapezoidal tube, so it is necessary to maintain the scrubbing regularly to ensure that the passage is smooth and without hanging.

Second, we should vigorously improve the operating level of the operators, strengthen the training and training of knowledge, strengthen the operation tour, improve the initiative, enthusiasm and regularity of the operation, and pay attention to flood prevention during the tour operation. Strictly reverse inspections and implementation of flood prevention and evaluation. It is an important measure to ensure the quality of products. Through this work, the awareness of workers in various processes is improved. Reduce the number of fakes to a minimum. We classify counterfeit counter inspection items into three categories: raw materials, semi-finished products, and finished products. According to different types, we propose specific flood control and catch-up projects, with clear penalties.

In addition, the operation management must also pay attention to errors and abnormalities in the production process. Wrong fiber, wrong barrel, wrong tube, wrong packing, etc. Coarse, spun yarn draft zone, damaged aprons, lack of spacers, etc. Abnormal spinning, abnormal slubs, spinning spindles slipping on and off, siro spinning single yarn, cross-spinning, Siro compact spinning Broken grid, blocked pipe, abnormal suction negative pressure, etc. It is necessary to supervise and inspect the implementation of normal operations of employees and give them proper assessment. Through management, inspection, assessment, reduce the number of unqualified joints.

3, strengthen equipment maintenance and overhaul

In terms of equipment, we should focus on the scrubbing work of each process channel. Whether it is a drive machine or a stop-and-start platform, it must be maintained in place according to the cycle, and it must be kept in good condition so that driving at any time can ensure quality compliance.

The pros and cons of equipment operation directly affect the improvement of product quality. During the production process, due to the abrasion of bearings, gears, etc., the quality problems such as the dryness of the detail yarns may occur. Therefore, it is necessary to strengthen the periodical maintenance and daily maintenance of the main equipment. Each branch and each section must strictly follow the company's specified maintenance period, formulate a monthly operation plan, and perform equipment maintenance according to the schedule. Each branch and section shall check and evaluate the maintenance machine according to the responsible person and operation plan. The company shall make corresponding requirements every month according to the inspection conditions and supervise and instruct the inspection of the branch and the working section.

At present, the production equipment used by the company is first-class spinning equipment. With advanced design and reasonable structure, it is necessary to use these equipments to reduce failures and lubrication management is of utmost importance. According to the requirements of various equipment instructions and the transmission forms, speeds, loads, and heat levels of the relevant transmission components, we can determine reasonable oil and refueling cycles and oil quantities so that irregular wear and damage to mechanical components will continue to decrease.

Spinning component equipment is a key component of spinning equipment. The selection and use of special components directly affects production efficiency and product quality. We should select the appropriate brand and model of spinning components from the requirements of ensuring product quality stability and reducing machine material costs according to the different types of products and the different forms of spinning. The replacement of various parts and the grinding of related equipment must be planned and evenly arranged according to the cycle regulations, so as to avoid the fluctuation of product quality due to the improper use or overdue period of the special equipment, and even lead to abnormal machine parts. damage.

4, strengthen the management of temperature and humidity

The temperature and humidity control of each process should meet the requirements of fiber absorption and desorption in the spinning process, so that the fiber is in the dehumidification process from the open cotton to carding, from the carding to the coarseness in the process of moisture absorption, from coarse to fine yarns are in weak condition. Dehumidification process. According to the season or climate change to do a good job of temperature and humidity adjustment, summer to prevent high temperature and humidity, winter attention to keep warm, a longer time to stop and then drive, the workshop to open air conditioning in advance, after the warm-up and then drive. Strengthen the control of temperature and humidity, reduce the difference between the temperature and humidity of the workshop, prevent fluctuations in the temperature and humidity areas or external environment caused by occasional gauze.

5. Reasonable setting of yarn clearing parameters for the winder

First of all, we must give full play to the function of removing yarn defects in the electronic yarn clearing machine in the winding process, but we must consider the production efficiency, labor and cost consumption. The long-term production practice has proved that, on the basis of ensuring the normal production efficiency of the winder, a reasonable setting of the clearing parameters will have a better effect on the removal of harmful yarns, and can better meet the quality requirements of users.

Secondly, the data of 100,000 meters of yarn inspection were used as the basis for adjusting the cleaning process. Reasonably adjusting the electronic clearing parameters of the winder has practical guiding significance for controlling the product quality. For the cotton yarn with low quality requirements, the main function of the electronic yarn clearer is to remove coarse, large and long yarn defects; With higher demands for cotton yarn, the electronic yarn clearer also has to take on the task of removing some of the neps and short thick sections.

In addition, for the removal of yarn defects, the origins of raw yarn yarns, draft yarn defects, and operation and management yarn defects must be found based on the distribution and quantity of 100,000-meter yarn defects, and they must be controlled during the production process. It is also not possible to completely rely on the electronic yarn clearer to remove the yarn defect. The yarn quality should be determined according to the requirements of the fabric, and the requirements of different fabric structures on the yarn defect should be ascertained to adjust the parameters of the electronic yarn clearer so as to reduce the pressure of the electronic yarn clearer.

Third, the conclusion

Sporadic yarn defects are a quality problem that has a greater impact on production and quality in the spinning process. The reason for this is related to the entire spinning process, which is closely related to many aspects of production management. Therefore, to solve the sporadic gauze problem, we should start from the actual production of the enterprise, through in-depth and meticulous investigation and analysis, find out the causes and laws, and adopt the method of system engineering to adopt technologies from the aspects of raw materials, equipment, technology, operation, and temperature and humidity. And management measures, the establishment of a sound and effective quality information feedback and error analysis tracking system and standardized, standardized, procedural production management system, pay attention to details, and strive to achieve refined management, can we achieve better results. As the saying goes, "The method is always more difficult than it is." "I can't think of it, I can't do it."