Concentrated spinning, as a new ring spinning method to improve yarn quality, has attracted more and more attention. How to improve product quality has attracted more and more attention from spinning companies. This article mainly introduces several common factors affecting the quality of agglomerated spinning yarns.
Exhaust volume of negative pressure fan and negative pressure of negative pressure pipe
The negative pressure of the negative pressure tube is the most direct and critical factor affecting the quality of the concentrated spinning yarn. Facts have proven that the amount of negative-pressure fan exhaust will directly affect the amount of negative pressure; in addition, the accumulation of flowers in the negative-pressure fan wind box is also a key factor affecting the negative pressure of the negative-pressure tube. In daily production, it is necessary to clean up the bellows accumulated flowers in time to keep the negative pressure stable.
According to actual testing and production findings, the negative pressure of agglomerated spinning needs to be maintained at 2.4 kPa to 3.0 kPa. If the negative pressure is too low, it will cause an increase in the head breakage rate, an increase in hairiness, a long hairiness, and a large unevenness of hairiness. According to actual measurements, under the same temperature and humidity conditions, when the negative pressure is between 2.4 kPa and 2.7 kPa, the difference between the negative pressure of the front and rear of the car is about 150 Pa to 350 Pa, and the difference in hairiness is about 30%. For example, the number of tail hairs on the C 7.29 tex yarn is 812.20 pieces / m, while the head is 1065.40 pieces / m. Production practice proves that a 1008 spindle spinning frame can choose a 4.2 kW negative pressure fan, and a 512 spindle spinning frame can choose a 2.4 kW negative pressure fan. Properly increasing the speed of the negative pressure fan can reduce the negative pressure difference between the head and the rear, and minimize the impact of the negative pressure difference on the yarn quality. Each time you sweep the car, you can remove 6 to 8 negative pressure pipes on both sides of the tail end, turn on the negative pressure fan, and suck out the accumulated flowers accumulated in the negative pressure air cylinder to clean it.
Movement state of whisk on negative pressure tube
The state of movement of the sliver on the negative pressure tube is an important factor affecting the yarn dryness. Under normal circumstances, the sliver is transferred from the roller to the negative pressure tube and the process of moving on the negative pressure tube. In the middle, the sliver moves in a relatively straight and continuously folded state. However, due to some factors, the movement state of the sliver will change.
Movement state of the sliver in the process of transferring from the roller to the negative pressure tube
In actual production, due to factors such as excessive cradle pressure, static electricity accumulation, bad surface of the rubber roller, and low negative pressure of the negative pressure tube, the sliver falls or skews in the "uncontrolled area" between the roller and the negative pressure tube. The phenomenon of yarn dryness will be significantly affected. Therefore, the pressure of the aggregate spinning cradle should be controlled to be small, to prevent static accumulation, to maintain the surface roughness of rollers and rubber rollers, to treat the rubber rollers with ultraviolet rays to prevent sticking and to maintain the normal pressure of the negative pressure tube.
Movement state of whisk on negative pressure tube
In actual production, there may be a phenomenon of a large increase in hairiness, a sharp increase in the head breakage rate or all head breakages. The main reasons are that the negative pressure fan has not been started or the negative pressure bellows have not been cleaned in time for a long time, making the negative pressure too small . Sometimes some single-spindle breakage rates are high or the spinning is not normal. The main reason is caused by the accumulation of flowers on the output end of the suction tube of the negative pressure tube. You can clear the accumulated flowers in the grid circle. Try to choose anti-static grid circles, and choose a reasonable mesh grid circle.
The effect of temperature and humidity in the workshop
During the production of agglomerated spinning, due to the effect of suction and exhaust air, the temperature of the workshop will be significantly uneven at the front and rear of the car. This unevenness will show seasonal differences. The temperature difference in winter is about 2 ℃ ～ 4 ℃, and in summer it is about 3 ° C to 6 ° C. Temperature and humidity are an important factor affecting hairiness. According to actual measurements, the number of hairiness and neps on the tail of the car is about 40% higher than that of the front. Therefore, maintaining the normal temperature and humidity in the workshop and reducing the temperature and humidity difference is an important measure to improve product quality.
Cradle pressure
The cradle pressure directly affects the yarn quality. Excessive cradle pressure may easily shorten the service life of the front rubber roller, cause the front rubber roller to be concave, and may also cause the rubber roller mechanical waves. The normal use period of the front rubber roller is about 2 months. When the pressure is too large, it will be unfavorable for holding the roving for one and a half months, causing a rapid increase in broken ends. Therefore, the accumulative spinning pressure should not be too large, and it is generally appropriate to control it from 160 N / twin to 180 N / twin.
Influence of spinning process on yarn quality
The size of the floating area
The floating zone is a key factor affecting yarn quality. The size of the floating zone should be the same, and the pressure rod should be in the right position. The position of the pressure rod will be too large, and the fiber will not be controlled effectively, and even a long rubber ring will appear; while the position of the pressure rod too far will cause the roving to "run up", and the pressure rod cannot be used. Role, if the pressure rod mills the front roller, it will also cause the roller mechanical wave to appear. In production, it is advisable that the rubber roller has a forward stroke of about 2 mm to 3 mm, and the maximum should not exceed 3 mm. If the forward stroke is too large, it will easily form an anti-surrounding arc, resulting in a decrease in yarn quality and an increase in end breaks. . Too large agglomeration spinning floating area can also easily cause the front rubber roller to press the grid circle. When the sliver moves to both sides of the yarn guide, the sliver swings left and right at the suction groove, which affects the yarn quality.
Spinning draft
Reasonable drafting distribution is also an important factor for improving yarn quality. According to experiments, when spinning 11.7 tex cotton yarns, the yarn quality at different back draw ratios is also significantly different.
When selecting the draft multiple, you cannot blindly pursue good yarn sliver and neps. As the draft multiple continues to increase, the unevenness of the long and medium segments of the yarn will increase. In the selection of agglomeration spinning process, in addition to the critical draft multiple, the draft ratio in the back zone can be appropriately increased, and the spindle speed can be appropriately increased, thereby increasing the yarn output and improving the efficiency.
In short, the optimization of yarn quality is a complex project, and the factors affecting yarn quality are also complex and diverse. Therefore, when optimizing the yarn quality, we must consider it in order to obtain the best yarn quality.
