The yarn defect indicator is one of the important indicators that reflects the quality of products of cotton spinning enterprises. Reducing harmful yarn defects is a regular basic work for cotton spinning enterprises, and it is also the main content of enterprise production process control and quality control. How to reduce yarn defects must start from the root causes of yarn defects, so as to take effective preventive measures to reduce quality errors in each process and ensure the stability of the overall yarn quality. To control harmful yarn defects, you should pay attention to the following points.
Strengthen the allocation of raw cotton
In multiple optimization process tests, it was found that: the maturity of raw cotton, Moisture absorption performance, single fiber strength, crimp, bending rigidity, fiber elasticity and other indicators will affect the changing trend of yarn defects and neps during the spinning process. Raw cotton with good spinability is less susceptible to rubbing and entanglement during the spinning process. To form yarn defects, the fiber fineness is moderate and the short lint content is low. It is difficult to get entangled with each other due to friction during the spinning process, and it is even more difficult to adhere to the machine parts. The short lint content in the cotton should not be too high, and use zigzag cotton as little as possible. , and reasonably control the amount of backsplash used. When producing combed yarn, the amount of backsplash in the cotton blend is not allowed to exceed 3%; when producing knitting combed yarn, try not to mix backsplash in the cotton blend. The nep index control should start from raw cotton, and then be refined to each process. Through the technical measures of each process, the process parameters should be reasonably designed, and different control standards should be set according to different varieties.
Strictly control the temperature and humidity in the workshop
The impact of temperature and humidity on yarn quality cannot be ignored. We should ensure that the fibers are in a moisture absorption process from carding to thickening, and that they are in a weak moisture release process from roughening to spinning. This is helpful for preventing fiber disorder at the sliver edges and stabilizing the twist of the yarn. , It has a good effect in reducing static electricity, which is beneficial to reducing the details, thick places and neps of the yarn, and can also effectively avoid the entanglement of the sliver fibers on the roller rubber roller. Therefore, in terms of temperature and humidity control in the workshop, it is necessary to adhere to the adjustment principle of “moisture release in blowing and carding, moisture absorption in fine and rough, slight moisture release in spun yarn, and moisture absorption in self-winding”, and the actual moisture regain rate of each process in the workshop should be detected and tracked every day. The temperature in the workshop is maintained between 25°C and 30°C, and the relative humidity is controlled within the range of 50% to 55%. Yarn defects in the finished yarn will be reduced accordingly, and the yarn quality will be stable.
Strengthen the basic management of equipment to ensure the advancement of equipment
In the process of spinning quality control It is necessary to always “take raw materials as the guarantee, equipment as the basis, and operation as the key construction” to determine what kind of varieties to spin and what kind of raw materials to use. We must also ensure the intact condition of the equipment and the operation quality of periodic equipment, and optimize all aspects. The process parameters and process speed ensure the stable operation of the machine. Starting from the basic management of maintenance, we should strengthen the skill level of maintenance operators. They should be strict and conscientious in their work, strive for excellence in practical operations, and have certain analytical and solution capabilities. Everything must be combined with reality. “Equipment must obey the process, and the process must obey the process.” Quality, quality must obey the customer” principle.
Strict test standards and strengthen test analysis
For quality fluctuations generated during the test process control, Process and maintenance personnel should strengthen analysis, comprehensively consider the causes of failure caused by index fluctuations, and be able to quickly find solutions to index fluctuations and effective improvement measures. They should start from the root causes of quality problems that occur in this process, start with small problems, and be comprehensive and meticulous. Thoroughly check the mechanical status of the equipment, strictly check whether the process spacing and process components are correct, and strictly check whether key components and equipment meet the process standards. Quality problems discovered during routine tests must be dealt with quickly and inspected and repaired immediately. Never let the equipment become sick. operation, miss hidden quality risks, prevent unqualified products from flowing into the next process, and ensure the stability of the quality of this process.
Strengthen operation management
Operate strictly in accordance with the requirements of the process operation method. When cleaning, it is necessary to operate carefully, increase the number of rounds, strengthen the identification and control of various defects by front-line lathes, and do a good job in preventing and catching defects.
Strictly control the indicators of each process equipment
The neps that appear on the machine in each process equipment during production There are too many mechanical waves, draft waves and large CV values. Strictly control the quality fluctuations caused by machinery in cleaning, combing, coarsening and spinning processes. If there are any abnormalities, they must be resolved as soon as possible to avoid quality accidents.
Strengthen process technology management
Technical personnel should establish a quality information feedback mechanism to identify quality problems, A written notice will be sent to the process and machine where the problem occurred, so that proactive measures can be taken and rectification can be made in a timely manner.
Strict process parameter design and process implementation
The three processes of blow cleaning, carding and combing. During process design, Try to eliminate as many short lint and neps as possible, strengthen the process parameters of fiber carding, and for varieties with higher yarn index requirements, in the above three processes, on the premise of ensuring front and rear supply, Try to master the “light quantity, slow speed” process, which will help improve product quality. The three processes of drawing, roving and spinning are based on the process parameters of “strengthening the control of floating fibers and improving fiber straightness”. Especially in the spinning process, “strong control” is very conducive to improving the quality of the yarn. The process Parameters must be constantly updated according to customer needs, changes in raw materials, and changes in varieties, and must be constantly updated.Striving for improvement and reasonableness in the state, and you cannot use one process that remains unchanged all year round, let alone copy the process parameters. For knitting yarns, you must try to achieve a process design of “two large and one small”. In short, good process design is A product quality can be improved with low investment, quick results, or even no investment. Therefore, this work must be based on the actual situation of the enterprise, continuous innovation, and continuous optimization of process design. Different process standards can be introduced according to the requirements of different varieties. Adapt to enterprise production needs.
Reasonable process design requires careful operation by the maintenance workers, and the accuracy of the process requires their close cooperation. Due to maintenance operation errors, deviations in the process design will occur, which will affect the production process. The product quality data of this process is accurate. Therefore, process designers must not only do a good job in process design, but also pay attention to checking whether the process spacing and process components meet the design requirements, and often go deep into the front line of the workshop to check the work of process modification personnel. Quality, process design and process execution, and whether the process experimental data achieve the expected results. Only in this way can we ensure that good process design is effectively implemented and the machine production quality will meet the process design standards.
Strengthen employee training
Strengthen employee training, improve the quality of all employees, and strengthen employee quality awareness, Improve employee quality control capabilities.
In short, yarn defect quality management is a meticulous work. We must grasp the key nodes and focus on controlling the quality of this process in each process. Indicators, controlling the quality of yarn defects mainly depends on key factors such as raw materials, technology, equipment, operation, temperature and humidity. Reducing yarn defects and effectively controlling yarn defects is a systematic and complicated task. Prevention should be given priority and combined with actual production conditions, Starting from the causes and locations of yarn defects, establish a strict control system, strengthen fine management, strengthen operation management and equipment management, constantly innovate thinking, constantly learn new technologies, continue to optimize processes, use constantly updated advanced equipment, and apply In actual production, it will definitely play a positive role in reducing yarn defects and controlling the increase in the number of yarn defects.
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