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Many studies have been conducted at home and abroad regarding the characteristics of yarn hairiness and its impact on the efficiency of air-jet looms and the appearance of fabrics. Research has led to the development of various instruments for the measurement of hairiness quantity. USTER’s 2007 bulletin uses USTER evenness testers – 3, 4 and 5 models to add hairiness test blocks to test hairiness.
1. Germany’s Zweigle g565 g566 hairiness tester is the latest instrument for measuring the length and distribution of yarn hairiness. Some people have tested carded and combed yarns of cotton and viscose staple fiber and found that the hairiness length of spun yarns is distributed exponentially. About 75% of cotton yarns have hairiness and loop lengths less than 1 mm, while only 1 % of the hairiness length exceeds 3 mm. Hairiness 3 mm long and above is harmful hairiness. It will significantly affect the efficiency of the air-jet loom.
2. In addition to the German g565, the foreign yarn hairiness measurement instruments include the Swiss uster3-4-5 and the latest laboratory uster oh sensor. Combined with the uster tester5-s400 or uster tester5-s800 evenness tester to test yarn hairiness; there are also hairiness testers from the British Siley Research Institute, etc.
3. Domestic hairiness testers include yg172a and bt-2 online hairiness testers. The yg172a and yg171b hairiness testers are based on the yg171a. The progressively developed third generation hairiness tester. The yg172a type instrument is basically similar in principle to the Japanese dt201 and Silay hairiness tester, while the yg171b type instrument is similar to the g565 and is currently the most ideal hairiness tester in China. It can be tested 1-50 times continuously, and you can select it arbitrarily; the hairiness length can be measured at 1, 2, 3, 4, 5, 7, 10, and 12 mm at the same time. In addition, there is an automatic data display and printing recording machine, and the average value can be reported. Unevenness cv% and hairiness histogram, etc. , my country’s Changling Textile Electronic Instrument Factory produces and supplies the above instruments for detecting hairiness. The special yg172a hairiness tester can automatically test and statistically analyze the length, quantity and distribution of hairiness in the yarn. It is suitable for testing the hairiness of short fiber yarns and warp yarns after sizing. It uses the photoelectric conversion principle to convert the hairiness into The light changes caused by shading are converted into electrical signals, which are amplified and shaped to form hairiness counting pulses, which are converted and displayed by an electronic computer.
4. Today, when the hairiness problem is becoming increasingly prominent, especially in the era of the gradual expansion of air-jet looms, the detection and detection of yarn hairiness conditions Understanding is more important. Therefore, textile factories should have a hairiness tester, conduct routine and special tests, and report hairiness distribution fluctuations at any time, so as to take measures to reduce the amount of hairiness and improve product quality.
5. In addition, the foreign-produced bt-2 online hairiness tester is mainly used on sizing machines and warping machines to detect changes in hairiness before and after sizing. The situation is to improve the sizing formula and sizing process, improve the sizing quality, reduce warp breakage, reduce the weft stops related to the warp of the air-jet loom and improve the hairiness tester of the 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 a requirement for yarn hairiness testing on modern air-jet looms.
If the hairiness after sizing can be reduced by 70-75% compared to the hairiness of the original yarn, it proves that the sizing process is correct, and it will be effective for the air-jet loom. The opening creates conditions to ensure that the opening is clear and the opening height is ideal, thereby reducing weft stops caused by hairiness and improving the efficiency of the loom.
6. Modern high-tech hairiness detection technology and discussion of hairiness distribution. With the progress of yarn hairiness research, the technology of detecting hairiness has also Correspondingly, there have been new developments, from visual inspection and weighing to advanced detection methods such as photoelectric measurement and electrostatic methods. Non-electrical electrical measurement principles are applied to convert the amount of hairiness into electrical values related to hairiness. For example, the German zweigle565 hairiness tester uses Uster evenness tester-3, 4, 5 and the latest uster tester 5-s400-oh and uster tester 5-s800-oh evenness tester plus hairiness sensor, which can provide optional Reproducible and comparable h values for hairiness testing. uster me100 is specially developed for the Chinese market. The uster me100 has the characteristics of accurate and reproducible testing of important quality properties such as evenness and yarn defects, which can be compared with the uster bulletin. The uster evenness meter me 100 can not only test evenness and yarn defects, but also Optional hairiness sensor is used to test the yarn hairiness h value. Can be compared with uster bulletin. Others include the British Silay hairiness tester, the Japanese dt201 hairiness tester, and the yg172a and yg172b hairiness testers of my country’s Changling Electronic Instrument Factory. These detectors have played an important role in improving yarn hairiness research.
1. Distribution of yarn hairiness online
Use the German wzweigle565 hairiness detector to detect yarn The distribution of online hairiness length was measured and analyzed, and it was concluded that the cumulative distribution of yarn hairiness conforms to the law of negative exponential function, that is: n(x)=ae-bx——1 where n(x)─ is equal to Or the number of hairiness roots greater than x length.
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, and the harmful ones were 3 mm. aboveHairiness accounts for only 1%.
According to the hairiness distribution and actual production quality requirements, determine the hairiness length of 3 mm and above as the critical length or harmful length, and classify the hairiness distribution of the critical length of 3 mm As an important basis for assessing yarn hairiness.
2. The reference value of yarn hairiness in the Ust-Ust Gazette was clearly stipulated in the statistical data of 1989. In 2007 The bulletin also stipulates reference content and related curves, including hairiness value h, hairiness standard deviation sh, coefficient of variation and other indicators. The hairiness value h refers to the length of the fibers extending out of the yarn outside the yarn body within the 1 cm measurement range of the yarn. The cumulative length calculated in millimeters is the length of hairiness on the yarn per centimeter long × the number of hairiness roots. The hairiness value h is related to the yarn count and twist. The thinner the yarn, the fewer fibers in its cross-section and the fewer hairiness protruding out of the yarn. The greater the twist of the yarn, the greater the chance of hairiness being twisted into the yarn body, and the hairiness will be less.
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, the fabric will be There will be color difference rungs. Although the difference in hairiness distribution is not obvious on the original color cloth, there will be a significant difference after dyeing.
The standard deviation of hairiness ｓsh is the second indicator for assessing hairiness distribution. It is a value describing the hairiness variation inside the yarn package. Compared with the package yarn For packages, the difference in hairiness between the weft yarns of two adjacent packages will also affect the appearance of the fabric.
The coefficient of variation of hairiness is how cvh describes the overall hairiness distribution, and is used to assess the uniformity of hairiness distribution in 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 differences in hairiness h value between spindles and packages, and reduce the dispersion of hairiness distribution. Improve the uniformity of overall hairiness distribution.
Pure polyester short fiber pure or blended yarn, due to the presence of hairiness, will cause fabric pilling and affect the appearance of the fabric. It is hoped that the h value should be smaller .
3. Modern new spinning machines or rotor spinning are equipped with online monitors that use thermal, acoustic or tension sensors to detect abnormal operation. Some spindles or winding heads are even equipped with intelligent microelectronics technology to track and analyze the causes of abnormal problems and display reports on the screen, so that the quality of each spindle or winding head is completely under control to reduce The hairiness h value controls the difference between ingots and ingots and between sets. On ordinary ring spinning machines or winding machines, it is necessary to manually and repeatedly check the balloon condition of each spindle, etc., to ensure quality, and combine the test results of the hairiness detector to find abnormal factors and deal with them in a timely manner. Uneven hairiness distribution will cause Uneven dyeing of the fabric will cause dyeing defects. Hairiness with a length of more than 3 mm will affect the clarity of the opening of the air-jet loom, cause stops between the diameter and weft, and affect the efficiency of the loom. Hairiness will partially fall off during the spinning process, causing an increase in flying flowers, environmental pollution, defects, etc. A large amount of research has been conducted on reducing hairiness at home and abroad and many remarkable results have been achieved.
Spinning and winding are the main processes that cause hairiness to increase. Improper spinning will increase hairiness by 1.5-2.5 times. The winding process is due to The high winding speed, large tension and friction will increase the hairiness of the yarn by 3-4 times after winding.
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. Compact spinning ring spinning technology With the emergence of spinning triangle, the hairiness h value of ring spinning yarn is greatly reduced, the yarn surface is as smooth as silk, and the quality is greatly improved. 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 h value.
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