1. If the sizing technology is not good when the air-jet loom produces high-density fabrics, the warp hairiness will cause adjacent warp yarns to be entangled with each other and cause unclear openings. The hairiness on the warp yarns will be more than 3 mm. It will also cause weft insertion to fail. Taking 30-inch spun yarn as an example, if the hairiness length on the yarn is 3 mm, the diameter of the spun yarn will increase 18 times. The initial opening height of the air-jet loom is 3.5 mm. The presence of hairiness will reduce the effective height of the loom opening, making the warp opening unclear and the weft flying blocked, causing the machine to stop. According to statistics, 1/3 to 2/3 of the stops of air-jet looms are related to yarn hairiness. The hairiness length of warp and weft yarns is more than 3 mm. On the one hand, the effective diameter of the weft yarns also increases a lot. On the other hand, adjacent warp yarns are entangled, resulting in unclear openings and difficult weft insertion. Weaving defects will also occur, affecting product quality. 70% of the stops of air-jet looms are caused by weft reasons. Therefore, in the activities to improve the efficiency of air-jet looms, reducing weft stops is the main contradiction. Among the factors that cause weft stops, hairiness is important. One of the reasons.
2. The hairiness on the yarn falls off due to friction in various downstream processes, forming flying flowers that pollute the environment and endanger human health. It will also produce new defects that affect the quality of yarn and fabrics. decline and will have a negative impact on improving the efficiency of air-jet looms.
3. The uneven distribution of hairiness on the yarn and the formation of new neps by hairiness during weaving will affect the appearance quality of the dyed fabric, and some will form rung defects. For example, during the spinning process, the hairiness distribution on the yarn is different between the spindles of the ring spinning machine and between the bobbins of the winding machine. Since the hairiness protruding out of the yarn is easier to dye than the fibers inside the yarn, the gray fabric will be dyed. The final color difference results in rung defects.
4. Hairiness on yarn has obvious side effects on textile product quality, weaving efficiency and production environment. In the textile process, spinning and winding are important processes that produce hairiness. Among them, the spinning triangle area of the spinning yarn, the twisting elements such as the ring traveler, and the winding tension have a very significant impact on the generation of hairiness. When reducing yarn hairiness, efforts should be made to reduce the yarn hairiness H value and its distribution to control it within the 25% level of the 2007 USTER statistics.
The problem of hairiness in yarn has long attracted the attention of the textile industry at home and abroad, and many studies have been conducted, achieving remarkable results.
Factors affecting yarn hairiness
1. Factors affecting yarn hairiness of ring spinning frame
When the spinning frame is spinning, the fiber bundles are twisted under the action of the steel ring and the traveler after being led out from the front roller, and form a spinning twisting triangle area, which is an important part of generating hairiness.
1. The spinning triangle has a great influence on the hairiness of spinning yarn. According to foreign reports, the spinning triangle produces both hairiness and fly, which accounts for about 85% of the fly in the entire spinning workshop. , the number of hairiness caused is also very large, accounting for about 80%. The following examples illustrate the influence of the spinning triangle on the hairiness of spun yarns.
① The Indiana Textile Research Institute in the United States studied the impact of the spinning triangle area between the front roller and the yarn before forming on hairiness, and proposed the “air pressure” method of reducing or eliminating the spinning triangle area to effectively control and reduce the hairiness of spun yarns. The spinning method is to pull the fiber sliver out from the front roller jaw and immediately enter a small duct very close to the roller jaw (as long as it does not touch the roller). Install a very small holed casing. The compressed air enters the outer tube and then enters the inner tube through 4 small holes. The yarn is led from the lower end of the tube and enters the balloon spinning area through the leaf plate and yarn guide hook. The compressed air passes through The air path is then discharged from the small holes of the yarn outlet at the upper and lower ends of the tube. The test results of this “air pressure” spinning method show that the smaller the distance between the upper end of the casing and the front roller nip, the better the effect of controlling spun yarn hairiness. When the air pressure is 49.8kPa, the spun yarn has less hairiness. Since the compressed air forms an air pressure ring surrounding the yarn, the hairiness protruding from the yarn body is incorporated into the yarn body under the action of twisting. The spun yarn has very little hairiness and the yarn body is relatively smooth.
② When spinning the RJS804 air-jet spinning machine exhibited by Murata Corporation of Japan at the 1995 Milan Exhibition, the fiber bundle enters the nozzle as soon as it leaves the nip of the front roller. The wrapping of the fiber is completed at the bottom, so that the yarn obtains a certain strength. This spinning method eliminates the twisting triangle area of the spinning yarn, and the air-jet yarn spun has fewer yarn defects and hairiness. The number of 0.5 mm long hairiness within 10 meters of yarn length is 179, while ordinary ring-spun yarn As high as 3223, it seems that the presence or absence of the spinning twist triangle has a great influence on the hairiness of the yarn.
Murata exhibited N0851MVS (Murata Vortex) at the 1999 Paris Exhibition in France. Spinner) vortex spinning machine, which is composed of a drafting mechanism, a spiral nozzle, a hollow spindle and a winding system. The spinning speed is as high as 400 m/min. Since the spiral nozzle is very close to the front roller jaw, it cannot There is a spinning twisting triangle area, and the spun yarn has very little hairiness, and the twisting effect of the hollow spindle further reduces the shorter hairiness, so that the spun vortex yarn has less hairiness and yarn defects, and the hairiness is only that of ring-spun yarn. of 1/4～1/5, the yarn surface is smooth and silky.
③The German Zinser Company, Suesen Company and the Swiss Rieter Company have recently developed and produced a ring spinning machine (Corn-pact yarn) for compact yarns. The yarn strength is higher than that of traditional The ring-spun yarn is 20% higher and the hairiness is reduced by 80%, which improves the dyeing effect of the post-process.
The production technology of compact ring yarn is to install a condensing mechanism at the outlet of the front roller nip of an ordinary ring spinning machine, thereby eliminating the spinning triangle, so that the whiskers drawn out from the front roller are immediately controlled by the condensing airflow and corresponding mechanisms. , the spun yarn has much less bulk than ordinary ring-spun yarn, very little hairiness, the yarn body is as smooth as silk, and the fabric has a beautiful and excellent appearance, forming high-grade ring-spun yarn and fabrics. Since this kind of tight ring-spun yarn has less hairiness than ordinary ring-spun yarn, the task of dealing with hairiness in the next steps such as sizing and singeing is no longer important, and some can even be omitted (such as the singeing process).
The hairiness of compact yarn is significantly less than that of ordinary ring-spun yarn, see Table 1.
Note: 1. The twist of compact ring-spun yarn is 10% lower than that of ordinary ring-spun yarn, which uses knitting yarn twist.
2. Use Zweigle hairiness tester to test.
3. In the table, A-ordinary ring-spun yarn; B-compact ring-spun yarn.
④Using a collector with an appropriate opening width on the ring spinning machine will play a certain role in reducing the hairiness produced in the spinning triangle area. For example, a factory produces 65/35 polyester-cotton 45-inch When counting yarn, the opening width of the collector is reduced from 2.3 mm to 2 mm, and the number of hairiness of more than 3 mm per 10 meters of yarn is reduced from 14.3 to 22.6. However, because the general collector is not flexible enough, improper use will affect the evenness of the spun yarn.
⑤ Another important factor affecting the hairiness of the spinning triangle area of the ring spinning machine is the top roller of the spinning front roller.
A softer top roller should be selected according to the type of spinning yarn to increase the holding jaw area, form a good friction boundary, and reduce the spinning triangle area.
The front top roller must have antistatic capabilities to reduce or eliminate the electrostatic adsorption phenomenon caused by the high-speed rotation of the top roller and reduce hairiness. For example, the American Armstrong series rubber rollers (J-463 and ME-670) contain charge-releasing components that can reduce hairiness in the spinning triangle area. Currently, similar types of rubber rollers are also produced in my country.
Properly moving the top roller on the front roller of the spinning frame forward can reduce the area of the spinning triangle and also help reduce hairiness.
In addition, it is necessary to promptly clean the cotton wax and oil stains accumulated on the top rollers, and keep the upper and lower rollers smooth and free of scars, which can help reduce hairiness.
2. The influence of the twisting part of the steel ring and the traveler on the hairiness of the spun yarn
The steel ring and the traveler are important components for twisting and winding in the spinning process of the ring spinning machine. The quality of the cooperation between the steel ring and the traveler directly affects the spinning tension and the friction of the traveler on the spinning yarn. Generally, it can be changed in one exchange. Steel within the cycle There are a running-in period, a stable period and a decline period between the wire ring and the steel ring. During the running-in and decline periods, the coordination between the wire ring and the steel ring is poor, the spinning tension fluctuates greatly, and the friction on the yarn is also large, and the spinning Hairiness increases more. If the service life of the traveler is lengthened, in addition to the running-in period and recession period, the stable period will also be lengthened, which is the key to reducing hairiness. There are many new developments in steel ring and traveler technology at home and abroad.
① The Ceratwine ceramic ring/traveler series products developed by the German Tec company can operate continuously for 105 days without damage at a spindle speed of 17500 rpm, making the traveler In one exchange cycle, the spinning tension, friction on the yarn, yarn breakage and hairiness are all very small, which has a very significant function in reducing yarn defects, improving yarn quality and production efficiency.
②The ORBIT high-speed steel ring traveler used in the Hi-per-spin ring spinning machine produced by Rieter, Switzerland, is made of special wear-resistant materials and has the characteristics of friction resistance and long service life, and the steel ring is enlarged during design The geometric size of the traveler increases the contact surface by 4 to 5 times, thereby increasing the heat dissipation capacity and extending the service life of the traveler. At high speeds up to 25,000 rpm, hairiness will not increase. Still suitableChoosing a lighter traveler reduces the stress between the traveler and the steel ring and the friction on the spun yarn, thereby also reducing the amount of hairiness.
③The fluorine-plated wire ring developed by my country’s Shaanxi Textile Equipment Research Institute (later reorganized into Hengxin Company) has a service life of up to one month, which is 7 times longer than the service life of ordinary wire rings. ~10 days is many times higher, which greatly increases the stable period of cooperation between ring travelers and is very beneficial to stabilizing and reducing spun yarn hairiness.
④ At present, many cotton spinning enterprises in my country have promoted the application of new matte steel ring technology, which has a significant effect on reducing hairiness, reducing the number of hairiness of 2 mm and above by 30% to 50%. The number of long hairs is reduced by 50% to 70%.
⑤ In terms of the supporting use of steel ring travelers, a lot of attempts have been made in practice at home and abroad, and rich experience has been accumulated.
If the traveler is too light or too heavy during spinning, it will affect the change of spinning tension. If the traveler is too heavy, the spinning tension will be high, which will increase the friction of the traveler on the yarn. The yarn will also cause friction with the top of the yarn tube. For example, the traveler is too light, the spinning tension is too small, and the balloon is too large, causing the yarn to hit the yarn separation plate, which will increase hairiness.
A domestic factory conducted a comparative test on the impact of the use of wire rings of different weights on the hairiness of spun yarns when spinning combed 65/3545-inch polyester cotton, using Taicang 171 type hairiness test Instrument tests are shown in Table 2.
In addition to improving the matching of ring travelers and extending the service life of the travelers, domestic and international attention is also paid to using other methods to control the stability of spinning tension.
① Some new ring spinning machines at home and abroad are equipped with frequency conversion speed regulating devices, so that the spindle speed and traveler line speed of large, medium and small yarns can be adjusted accordingly, so that the spinning tension is controlled and stable, such as the Swiss Hi-per- Spin ring spinning machines, etc. are all Electronic computer simulation is used to control the spinning speed of large, medium and small yarns in the entire spinning process to stepless speed regulation, thereby effectively controlling the spinning tension. On the one hand, it prolongs the service life of the traveler. On the other hand, due to the stable tension, it reduces Fluctuations in yarn hairiness.
②InInstalling a balloon control ring on the spinning machine turns one large balloon into two small balloons during spinning, which also has a certain effect on reducing spinning tension and reducing hairiness.
③In the daily operation of the spinning frame, there are many management factors that cause the spinning tension to fluctuate and increase the hairiness of the spinning frame, such as the yarn guide hook, steel ring and spindle on the spinning frame. The three are not concentric, resulting in incorrect loops, collision with the gauze plate, etc., which will also increase hairiness.
Due to the abnormal twisting part of the ring traveler, the number of spun yarn hairiness will increase significantly. Therefore, the problem related to the steel ring, traveler and twisting part is to reduce the hairiness of the spun yarn. one of the important links.
2. The impact of winding production on yarn hairiness
At present, the advanced winding technology has entered the stage of automation and high speed. The linear speed of the automatic winding machine is as high as 2000 meters/min, which realizes yarn starting, knotting, yarn clearing, Automated functions such as online inspection of yarn defects integrate electromechanical instruments, but they also produce many unfavorable factors that increase yarn hairiness. For example, high winding speed will increase the friction between the yarn and the channel and groove drum. Due to the improvement of automation, the yarn unwinding from the bobbin must pass through many automatic checkpoints and undergo yarn clearing, splicing and other processes, which lengthens the processing route and increases the chance of yarn wear. In order to reduce the yarn hairiness caused by winding, the following measures are mainly taken on high-speed automatic winding machines at home and abroad:
1. The winding speed of the winding machine adopts frequency conversion speed regulation technology, so that the unwinding tension of the bobbin yarn and the balloon during winding are controlled, basically consistent, and the zero tension between the yarn and the channel due to excessive tension is reduced. The friction between components and air also reduces the friction caused by the slip between the cheese yarn and the grooved cylinder, thereby reducing the generation of hairiness, such as the German Autoconne r-238, 338, Italy’s Savio Espero and Orian models all use single spindle speed regulation technology to make the winding tension uniform. my country’s Qingdao Textile Machinery Savio Es-per0 automatic winding machine and Shanghai Second Textile Machinery Co., Ltd. The Autoconner238 automatic winding machines all have mechanisms for frequency conversion speed regulation and even control of winding tension.
2. The N7-V type produced by Japan’s Murata Company is equipped with a balloon controller, which is a patent. The controller can rise and fall according to the unwinding position of the bobbin, which effectively controls the tension change and is beneficial to reducing hairiness. In addition, the machine is also equipped with a grid tension control device to automatically adjust the winding tension to make the entire winding tension uniform.consistent.
At the 1999 Paris International Textile Machinery Exhibition, a newly designed vortex nozzle device PERLA was installed on the N7V-Ⅱ automatic winding machine exhibited by Murata Corporation of Japan, which replaced the Balcon balloon controller. The yarn was It passes through this vortex nozzle machine before being wound into a tube. When constructing, the longer hairiness protruding from the yarn body is wrapped on the surface of the yarn body under the action of high-pressure airflow from the vortex nozzle, thereby reducing the hairiness on the yarn and improving the appearance quality of the yarn. Due to the reduction of yarn hairiness, It also changes the operating status of the post-process and improves the efficiency of the loom and the appearance quality of the fabric.
3.Autoconner338 and Orin use a balloon breaker, 238 uses a spring-pressurized disc tensioner, which is easy to adjust, and Orian uses a pneumatically pressurized double tension disc for tensioning adjust. All of these control the unwinding tension and balloon of the yarn, making the tension stable and consistent, and reducing the increase in friction between the yarn, channel components and air due to excessive tension, thereby reducing hairiness. Take the Balcon balloon controller installed on the Japanese Murata pc21 automatic winding machine as an example. After installation, the winding tension remains stable during the entire winding process, effectively reducing the hairiness after winding and being significantly lower than without a controller. The hairiness of the yarn. Table 3 shows the comparison of the hairiness conditions of processed yarns with and without the balloon controller (the position of the yarn on the spinning tube is divided into 10 segments during winding).
Table 3 shows that the hairiness of the spun yarn after winding on the winding machine without a balloon controller is 2 times higher than before winding, while the hairiness after winding with a balloon controller is Yarn hairiness is significantly less than without controller. Even if the winding speed increases after adding a controller, the hairiness will decrease.
4. Under the possible conditions, a lower winding speed should be appropriately selected to reduce the winding tension accordingly, which is to reduce yarn hairiness
One of the methods, for example, the yarn hairiness number is 10% higher when the winding speed is 2200 meters/minute than when the line speed is 80O meters/minute.
5. After the yarn is wound, the hairiness increases, and the CV% of the hairiness distribution decreases. The more times the yarn is wound, the more hairiness increases, so, Rewinding should be minimized during production.
6. Among the winding process parameters, the winding tension, clearing plate spacing, yarn guide distance, etc. all have an impact on hairiness.
7. The hairiness of coarse yarn and chemical fiber blended yarn increases significantly after winding.
8. When winding on the winding machine, the main place where hairiness occurs for ordinary ring-spun yarn is when the ring-spun bobbin is unwound because the surface structure of ordinary ring-spun yarn is relatively loose. , the yarn hairiness increases a lot due to the effect of air tension. However, the hairiness of tightly spun yarn does not increase significantly after winding under the same conditions, indicating that the yarn hairiness is closely related to the spinning process. The main reason for the increase in yarn hairiness on the winding machine is that the surface structure of the spinning yarn is relatively loose. When unwinding on the winding machine, new hairiness is formed due to the tension of the unwinding balloon, which increases the yarn hairiness a lot.
3. Overview of factors affecting yarn hairiness
1. Many spinning characteristics on ordinary ring spinning machines will affect the hairiness of the yarn. From long-term practice, it can be seen that due to the abnormal twisting part of the ring traveler, the number of spun yarn hairiness will increase significantly, so Solving the problems related to the steel ring, traveler and twisting part is one of the important steps to reduce the hairiness of spun yarn; under the condition of soft top roller and large distance block, the yarn hairiness value can be lowered. Choose a softer top roller according to the type of spinning, increase the area of the holding jaw to form a good friction boundary and reduce the spinning triangle area; appropriately move the top roller on the front roller of the spinning machine forward to reduce the area of the spinning triangle area. It also helps to reduce hairiness; the correct use of the front roller collector will have a significant effect on reducing hairiness; the influence of the yarn guide hook on yarn hairiness is not obvious.
2. Compact spinning ring spinning technology is an effective new technology that reduces spun yarn hairiness, increases spinning strength, and improves spun yarn evenness. Generally, compact spinning ring spinning technology can reduce hairiness by 80% or more than ordinary ring spinning machines. Strength increases by 10% to 20%.
3. Because new spinning yarns such as rotor yarn have a wrapped yarn structure. There is almost no spinning triangle during spinning. The fiber tail ends and loops protrude from the yarn body. The fiber tail ends and loops wrap around the yarn body and keep the fibers tightly wound toward the yarn core. Therefore, The hairiness of new spinning yarns such as rotor yarn is much less than that of ring yarn.
4. Winding technology has entered a high-tech stage of automation and high speed. The linear speed of automatic winding machines is as high as 2000 m/min. There are many unfavorable factors that increase yarn hairiness, especially because the structure of ordinary ring-spun yarn is more fluffy than compact yarn. , when the spun yarn bobbin is unwound, the tension is large and the balloon is large, which significantly increases the hairiness. Reduce and control the unwinding tension of spun yarnsIt can reduce the hairiness of ordinary ring-spun yarn.
5. Workshop temperature and humidity, yarn twist, equipment status, properties of spinning raw materials (fiber maturity, cohesion, fineness, length unevenness, etc.), uniformity of fiber blended yarn in blended yarn And the spinning process also has a certain impact on the hairiness of the yarn. The nature of the fiber affects the amount of yarn hairiness. The finer the fiber, the more hairiness the yarn has. In blended ring-spun yarn, polyester short fiber is related to yarn hairiness. Immature fiber content and short pile rate are also important factors in producing hairiness. High immature fiber content and high short staple rate. High shortness and high hairiness. Therefore, the immature fiber content and short staple rate must be strictly controlled in spinning production.
6. The test speed has a certain impact on the USTER hairiness value. As the test speed increases, the hairiness value also increases. When the test speed exceeds 100 m/min, the statistical significance level of hairiness is at 5%. When the ring yarn is wound into a package, it shows a slight difference because the hairiness on the yarn surface changes direction when the yarn is unwound. Hairiness increases when the test yarn speed exceeds 200 m/min (statistical significance level is 5%).
7. The test length has no effect on the USTER hairiness value, but when the ZWEIGLEG565 hairiness tester is used, the hairiness index value decreases when the test length increases (the statistical significance level is 5%). The ZWEIGLE hairiness tester has no effect on interference. more sensitive to impact.
8. The friction phenomenon of yarn itself occurs during the unwinding, transportation and storage process of bobbin or package yarn. Self-friction has little effect on yarn hairiness distribution, but the hairiness of pure cotton ring-spun yarn changes after self-friction: firstly, the hairiness of fine-count yarns decreases, and secondly, the hairiness of coarse-count yarns increases. However, modern spinning production has achieved fineness. The automatic production line is connected to automate the transportation of spun yarn bobbins. The bobbins on the Xinluolian automatic production line are transported by nail trays or conveyor belts, and the bobbins do not collide or rub against each other. At present, cheese yarn is packaged and transported between spinning mills and weaving mills in my country in polyethylene woven bags, which causes serious damage and friction to the outer surface of the yarn and also affects hairiness, which should be improved.
Distribution and detection of hairiness on yarn
With the progress of yarn hairiness research, the technology for detecting hairiness has also developed accordingly, from visual inspection and weighing to advanced methods such as photoelectric measurement and electrostatic methods. The detection method applies the principle of non-electrical measurement to convert the amount of hairiness into the electrical value related to hairiness. Such as the German Zweigle565 hairiness tester, the Swiss USTER Type 3, 4, and 5 evenness tester hairiness testing institutions and the British Siley hairiness tester. my country’s Taicang Electronic Instrument Factory’s YGl71A, YGl71B hairiness tester, BT-2 online hairiness tester and Changling Spinning Electric’s YGl72A yarn hairiness tester, etc. These detectors play an important role in the study of yarn hairiness.
1. Distribution of hairiness on yarn
The German Zweigle565 hairiness detector was used to measure and analyze the distribution of hairiness length on the yarn, and it was concluded that the cumulative distribution of yarn hairiness conforms to the law of negative exponential function, that is:
In the formula: N(x)——the number of hairiness roots equal to or greater than x length; x——the set length of hairiness; A, b——reflect the yarn hairiness characteristics , as an index to evaluate hairiness.
The G565 hairiness tester was used to conduct a large number of tests on the hairiness of various types of yarns. It was found that more than 75% of the hairiness lengths were less than 1 mm, while the harmful ones were more than 3 mm. Hairiness accounts for only 1%.
According to the hairiness distribution and actual production quality requirements, determine the hairiness length of more than 3 mm as the critical length or harmful length, and use the hairiness distribution with a critical length of 3 mm as the assessment An important basis for yarn hairiness.
In ring-spun yarns, the number of hairiness above 3 mm is relatively high, especially in polyester-cotton blended yarns. In air-jet spinning, there is no spinning triangle during the twisting process and high-speed airflow is used to twist the fiber bundles that have just left the nip of the front roller, making the yarn smooth.
The vortex spinning machine newly developed by Murata Corporation of Japan is also a new spinning technology in the non-woven triangle area. The vortex spinning not only has less and short hairiness, but also has strong spinning power and environmental protection. Spindle close.
The detection results of the German Zweigle565 hairiness detector on the hairiness length distribution on the yarn have a very good guiding role in improving the efficiency of air-jet looms. It can provide influence on improving the efficiency of air-jet looms. The distribution of harmful hairiness related to machine efficiency can be used to facilitate the adoption of corresponding measures to arrange production.
1. The assessment of yarn hairiness in the USTER statistical data (Uster Gazette) has been clearly stipulated in the statistical data as early as 1989, 1997, 2001, 2007 The annual bulletin also stipulates the assessment contentAnd related curves, Swiss Uster types 3, 4, and 5 have the function of detecting yarn hairiness, and are compared with Uster statistical data hairiness value H, hairiness standard deviation Sh, coefficient of variation and other indicators.
The hairiness value H refers to the cumulative length in millimeters of the fiber length extending out of the yarn within the 1 cm measurement range of the yarn, that is, the hairiness value per unit length of the yarn (hairiness Length × number of hairs). The hairiness value H is related to the yarn count and twist. The thinner the yarn, the fewer fibers in its cross section; the number of hairs protruding out of the yarn is also less; the greater the twist of the yarn, the greater the chance of hairiness being twisted into the yarn body. Large and less hairy.
Practice has proved that when the hairiness value H of two adjacent cheese yarns used as weft yarns of a single-color dyed fabric differs by 1 or more, color rungs will appear after the fabric is dyed. The difference in hairiness distribution is not obvious on the original color cloth, but there will be a significant difference after dyeing.
The standard deviation Sh of hairiness is the second indicator for assessing hairiness distribution. It is a value that describes the hairiness variation inside a yarn package. Compared with cheese yarn packages, two adjacent The difference in hairiness between weft yarns will also affect the appearance of the fabric.
The coefficient of variation of hairiness is CVh, which describes the overall hairiness distribution and evaluates the uniformity of hairiness distribution of mass-produced yarns.
In production practice, special attention should be paid to the assessment of hairiness H value and standard deviation. Efforts should be made to eliminate the difference in hairiness H value between spindles and packages and reduce the dispersion of hairiness distribution. degree, improving the uniformity of overall hairiness distribution.
For pure polyester short fiber pure or blended yarn, the presence of hairiness will cause fabric pilling and affect the appearance of the fabric. It is hoped that the H value should be small.
The German Zweigle 565 hairiness tester tested carded and combed yarns of cotton and viscose staple fiber. It is believed that the distribution of hairiness length of spun yarns is exponentially distributed. Cotton yarns are approximately 75% of the hairiness and loop lengths are less than 1 mm, while only 1% of the hairiness lengths exceed 3 mm.
2. In addition to the German G565, foreign yarn hairiness measuring instruments, Swiss Uster type 3, 4, and 5 also have the function of detecting yarn hairiness, and the British Siley The institute’s hairiness tester, Japan’s DT201, etc.
3. The hairiness tester YGl72A and YGl71B supplied by the domestic Changling Textile Instrument Factory is the third generation hairiness tester YGl71A developed based on the YGl71A type. The principle of the instrument is basically similar to that of the Japanese DT201 and Silay Hairiness Tester, while the YGl71B model is similar to the G565. It is currently the most ideal hairiness tester in the country and can be tested 1 to 50 times continuously, and can be selected at will. ; The hairiness length can be measured at 1, 2, 3, 4, 5, 7, 10, and 12 mm at a time. In addition, there is an automatic data display and printing recording machine, which can report the average value, unevenness CV% and hairiness value, etc. Ling Textile Electronic Instrument Factory also produces similar instruments for detecting hairiness and supplies them to textile factories. It uses the principle of photoelectric conversion to convert light changes caused by hairiness shading into electrical signals, which are amplified and shaped to form hairiness counting pulses.
4. In addition, the domestic BT-2 online hairiness tester is mainly used on sizing machines and warping machines to detect changes in hairiness before and after sizing. It is an important tool to improve the sizing formula. , sizing process, improve sizing quality, reduce warp yarn breakage, reduce weft stops related to warp yarns of air-jet looms, and improve the hairiness tester of cloth surface quality. The instrument uses a single-chip computer, is powered by a rechargeable battery, has an LCD display, and can report mean square error, average value, unevenness, etc. Because the instrument is light and small, it is convenient for online testing. The maximum test yarn speed is 1000 m/min, and the hairiness setting lengths are four test heads of 1, 2, 3, and 5 mm. It is also an essential instrument for the production of modern air-jet looms.
2. Detection of yarn hairiness
Today, when the problem of hairiness is becoming increasingly prominent, especially in the era of the gradual expansion of air-jet looms, the hairiness of yarns is even more important. Therefore, textile factories should have a hairiness tester, conduct routine and special tests, and report the fluctuations in hairiness distribution at any time, so as to take measures to reduce the amount of hairiness and improve product quality.
1. If the hairiness of the warp yarn after sizing is reduced by 70% to 75% compared to the hairiness of the original yarn, it proves that the sizing machine and sizing process are correct, and the air-jet loom can be effective. The opening creates conditions to ensure clear openings and ideal opening heights, thereby effectively reducing weft stops caused by hairiness and improving loom efficiency.
2. Some new foreign spinning machines are also equipped with online monitors, which use thermal, acoustic or tension sensors to detect abnormally operating spindles or winding heads (fine connections). Some are even equipped with intelligent microelectronics technology to track and analyzeThe causes of abnormal problems are reported on the screen, so that the quality of each spindle or winding head is completely under control, so as to reduce the difference in hairiness value H between spindles and between spindles and between stations, and control the differences. Within 1 to ensure the stable quality of dyed fabrics.
3. On ordinary ring spinning machines or winding machines, the balloon condition of each spinning spindle must be manually and repeatedly checked for quality control, combined with the test results of the hairiness detector To detect abnormal factors and deal with them in time.
4. In addition to the uneven distribution of hairiness that will cause uneven dyeing of the fabric and cause dyeing defects, hairiness with a length of more than 3 mm will affect the clarity of the opening of the air-jet loom and cause stops in the warp and weft directions. , affecting the efficiency of the loom. Hairiness will partially fall off during the spinning process, causing an increase in fly flakes, environmental pollution, and defects.
5. Spinning is the main process for increasing hairiness. Improper spinning will increase hairiness by 1.5 to 2.5 times. When producing ordinary ring-spun yarn in the winding process, due to the high winding speed, high tension, and high friction, the hairiness of ordinary ring-spun yarn will increase by 3 to 4 times after winding. However, the hairiness will be affected when producing tight ring-spun yarn. Not big.
6. The spinning triangle area and the twisting part of the steel ring and traveler on the spinning frame are the main factors causing the increase in hairiness. The emergence of compact ring spinning technology has eliminated the spinning triangle area, greatly reducing the hairiness value H of ring spinning yarn, making the yarn surface smooth and silky, and greatly improving the quality. Great progress has also been made in the coordination of steel rings and travelers. In particular, the service life of steel rings and travelers has been improved, which has stabilized the spinning tension and the hairiness value H.
7. While realizing high-speed winding automation, the winding process effectively uses variable frequency speed regulation technology to control the winding tension and achieve low-tension winding, and the hairiness value H is also obtained. Control and reduction, the use of some balloon controllers is also beneficial to reduce hairiness.
8. The application of advanced yarn hairiness testing instruments is a necessary means to reduce the yarn hairiness value H. In the normal production of the enterprise, according to the requirements of USTER statistical data, advanced testing instruments are used for tracking and testing, and the hairiness detection test is included in the routine tests. According to the hairiness value H and standard of yarn proposed by USTER Bulletin Indicators such as difference Sh and variation number CVh are carried out to meet the standards, so that the yarn hairiness value H and the degree of dispersion can be controlled within the level of USTER 2007 bulletin.
The German Zweigle565 hairiness detector and the Changling Textile Instrument Factory YG171B hairiness meter are used to measure the hairiness length distribution on the yarn, which can reflect the hairiness distribution of 3 mm and above in the hairiness length distribution. , it is very important to improve the efficiency of air-jet looms and has a direct guiding role.
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