Some quality problems in spinning, such as hairiness, cotton knots, foreign fibers, strong weak ring and immature fiber content percentage are directly affect the quality of spinning yarn and even fabric quality and downstream process production efficiency of the important issues, should pay great attention to, set up prevention, the application of a variety of high-tech testing instruments online and offline monitoring and resolution of the above problems, at least to detect the problem in time, take measures Reduce the quality problems found. In order to further improve the quality of spinning.
The danger of knots
The amount of cotton knots in the spinning yarn not only affects the appearance of the spinning yarn and the quality of this color cotton fabric, and will directly affect the fabric coloring effect, resulting in dyeing defects, with the increasing requirements for the appearance of fabric quality, cotton knots have been listed as an important manipulation of defects.
The formation and distribution of cotton knots
(1) cotton harvesting there are many harvesting methods will make the original cotton in the cotton knot impurities, the current harvesting methods are broadly divided into manual picking and mechanical harvesting methods, foreign manual harvesting methods are mainly used for picking long-staple cotton and fine lint cotton, in addition, all mechanized harvesting, mechanical harvesting to the lint in a large number of impurities, and even a small number of cotton knots, to the gin to remove impurities bring difficulties, but also make the gin after the The raw cotton with a certain number of cotton knots.
(2) open cotton production in the removal of impurities in the original cotton and increase cotton knots and short lint is a contradiction, open cotton ministries to beat the faster the speed, the better the removal of impurities, the longer the increase open cotton production line process, the more cotton knots increase. Therefore, we should strive to open the cotton production line short process, optimize the process technology to remove impurities and produce cotton knots, and strive to open the cotton in the end of the force less increase in cotton knots and short lint.
(3) The greater the proportion of immature fibers in the raw cotton, the greater the chances of producing cotton knots and short lint, we should try to manipulate the distribution of immature fibers before the raw cotton enters the finishing line, to reduce the proportion of immature fibers in the blend and differences.
(4) card is to reduce the main process of cotton knots, many cotton knots can be combed on the card or detoxification, therefore, the card to do four fast and accurate, strengthen the combing, especially between the cover plate and the combing role of the tin forest to strengthen the new card equipped with a fixed cover plate, improve the feeding of the cotton Department of debris removal function and combing effect, these are very to very important role in reducing cotton knots.
(5) online and offline monitoring and manipulation of cotton knots in the raw cotton, so that the production of the increase in the number of cotton knots under control, the application of AFis raw cotton nature detector can check the percentage of immature fibers and the total number of cotton knots in the raw cotton packet by packet, more than the specified indicators to be removed, so that the number of cotton knots in the open combing process can be manipulated, the new card such as DK803, DK903, DC03, etc. can also be Online detection of the dynamic change of the cotton knot, according to the increase of the cotton knot over the limit alarm, automatic adjustment of the cover plate and the distance between the tin, automatic grinding cover plate, stable product quality.
(6) After a long period of practice and inspection of the accumulation of figures, the general standard of cotton knot manipulation is as follows.
Raw cotton 200 grains/g
Open cotton 400 grains/g
Carding 80 grains/g
Combed 20 grains/g
Raw cotton according to the initial finishing and the quality of the original cotton itself, the general quantification of cotton knots 200 / g, low 100 / g, high 400 / g.
The cotton knot in the opening and clearing process increases to 400 grains/g, low 200 grains/g and high 700 grains/g.
The raw card contains 80 cotton nodes/g, 200 nodes/g high and 50 nodes/g low.
After combing and carding, the cotton knots in the combed strips are generally manipulated to be below 20 grains/g.
Other processes, such as parallel, roving, etc., do not vary much in the amount of cotton knots, but they are slightly increased.
Immature fibers have a greater impact on the increase of cotton knots and short lint, should be manipulated when the distribution of immature fibers and the percentage of content of the raw cotton with cotton.
The concept of anisotropic fibers refers to the different coloring properties of cotton fibers and other fibers such as wool, hemp, silk, chemical fibers. Raw cotton mixed with these different coloring function of foreign fibers, will be in the downstream process such as knitted fabric, woven fabric caused by dyeing defects, not only deteriorate the physical appearance of the quality, but also make spinning enterprises are claimed, resulting in economic losses.
(1) currently our country has entered the WTO, different finishing methods around the world harvesting and packaging methods of raw cotton, domestic enterprises are applying, domestic raw cotton also mixed with foreign fibers, commonly known as & ldquo; three silk & rdquo;, severe WeiXie to our cotton textile weaving enterprise spinning quality and downstream processes of product quality, for this reason, many domestic enterprises have organized manpower into a station a workshop pick & ldquo; three silk & rdquo ldquo; three silk & rdquo;, with more workers, the effect is not stable and not complete, is to improve the quality of spinning and fabric appearance of the problem.
(2) at present in many open cotton production line added to remove the technical equipment of the anisotropic fiber, it is the use of the completion of the electrical principle combined with open cotton in the meticulous open loosening technology, the detection and removal of anisotropic fiber, like the German Trützschler SCFO foreign fiber detection system, installed in the card feeding part.
The basic condition for the application of this technology system is that the fibers must be opened and loosened separately in the process of opening and clearing the cotton, so that the fibers can be free and monofilamentous, and this device for removing foreign fibers is installed in the feeding part of the card in the clearing and combing system. The efficiency of the electronic yarn clearer on the automatic winder can be reduced by 50% and the efficiency of the automatic winder can be improved. If the open clearing system is not equipped with the device to clear the anisotropic fibers, the efficiency of the electronic yarn clearer on the winder will be cut off about 40 times per 100,000m.
(3) Only the electronic yarn clearer of automatic winder to clear anisotropic fibers, but no open clearer to clear anisotropic fibers, the electronic yarn clearer cuts off more times and the automatic winder has low productivity.
If there is no electronic yarn clearer for clearing anisotropic fibers in the automatic winder, the clearing of anisotropic fibers is obviously not complete.
Only if there is an anisotropic fiber clearing system in the open-end production and an electronic clearer for anisotropic fibers in the automatic winder, the removal of anisotropic fibers can be more thorough and get better results.
(4) There are many domestic electronic yarn clearers for clearing anisotropic fibers and winders for clearing anisotropic fibers, which can be selected according to specific conditions.
Immature fiber: It is a cotton fiber with thin cell wall, large middle cavity, no twist, and partial ribbon fiber.
(1) Because the immature fiber and mature fiber color performance is not the same, so immature fiber distribution in the spinning process will be uneven in the defective cloth in the cross-file defects, immature fiber content is lower, the cotton fiber color performance consistent, less dyeing defects.
(2) immature fiber rigidity is poor, low strength. Therefore, it will affect the production of spinning, quality, under the same conditions will increase the cotton knot and short lint, yarn breakage increase, production instability.
(3) abroad has long been immature fiber content as a percentage in the cotton blend as an important indicator to manipulate.
(4) Application of cotton fiber properties detector such as USTER AFIS for bale by bale inspection of the distribution of immature fibers in the original cotton, can be accurate, rapid detection of immature fiber content of the instrument.
(5) It is recommended that the percentage of immature fiber content between a batch of raw cotton bale and bale in the cotton blend is within 2%, and the percentage of immature fiber content between batch and batch does not exceed 0.5%. Mature
Spinning yarn hair feather in quite some fabric products is harmful, very is the warp and weft yarn for jet loom are required to warp and weft yarn complete amount of hair feather reduction, especially more than 3 mm harmful hair feather. But some fabric very spinning yarn contains a certain amount of hair feathers, in order to make the fabric with a certain style.
(1) the main process of generating hair feathers is spinning, in the spinning machine has an impact on the generation of hair feathers are two places. One is the spinning triangle, that is, from the spinning front roller jaws leading to the twist point between the spinning triangle, according to foreign information reports, the triangle generated by the spinning hair feathers account for 80% to 85% of the entire spinning line hair feathers, fine yarn shop more than 80% of the flying flowers attached to the spinning triangle generated; second is the winding part.
(2) the emergence of compact spinning technology, basically remove the spinning triangle, therefore, spinning out of the yarn hair feather very little, the yarn body complete smooth as silk, basically solve the problem of hair feather in the spinning production of spinning yarn.
(3) spinning machine roll twist part of the steel collar, steel wire ring is also the part of the yarn hairiness, most of the domestic platform, steel wire ring life is very low, steel collar life of only 9 months, steel wire roll life of only one week, due to the steel collar steel wire ring mismatch, the stability period is too short, so that the warp tension is very unstable, especially in the spinning production of large yarn and small yarn spinning tension is greater, not only will produce broken head, and will produce hairiness. In recent years, China's steel collar life after the revolution of materials and finishing process, life has been improved to 3 years ~ 5 years, wire ring life has also improved, like fluorine wire ring.
Foreign general production of steel collar, steel wire ring is in a business, steel collar, steel wire ring anastomosis shape to get a good design, extend the service life, improve the quality of matching, like Switzerland Brooks steel wire ring, steel collar supporting the situation is very good, increase the contact surface between the two, so that the heat dissipation effect is good, extend the life, according to the factory experience, steel collar steel wire ring supporting the situation will significantly reduce hairiness.
(4) spinning parts in the roller, rubber roller, rubber ring, guide hook, up and down pin, collector, etc. all play a positive role in reducing hairiness, how in the absence of close spinning technology, complete may reduce the spinning triangle, is also a positive measure.
(5) the new spinning machine motor is frequency conversion speed control can be divided into 10 levels according to the spinning process from small to large yarn spindle speed, in order to manipulate the spinning tension consistent, stable spinning tension can reduce the size of the yarn hairiness.
(6) spinning yarn hairiness on the air jet loom efficiency improvement is very relevant, according to the survey of air jet loom using general ring yarn, due to hairiness caused by the warp and weft to stop the contract accounted for 2 / 3, so the hairiness problem should pay special attention to.
(7) Due to the uneven distribution of hairiness, the spindle difference is large, which will cause the fabric to produce cross-file dyeing defects caused by hairiness.
(8) Automatic winding machine has realized the automatic manipulation from big yarn to small yarn drop yarn rewind tension and winder winding tension, which also has a positive effect on reducing the number of hairiness when rewinding the tube yarn.
(9) The effect of winder on hairiness increase is for general ring bloom yarn with more hairiness, which continues to deteriorate to make significant hairiness increase, but does not include tightly spun yarn with little hairiness, for tight ring bloom yarn, the winder does not have an effect on the significant increase of fine yarn hairiness.
(10) the new spinning system, because basically no spinning triangle and steel collar, steel wire ring twisting system, so the air-jet spinning, vortex spinning and rotor spinning spinning line of hairiness are less than the general ring spinning yarn.
Average strength and strength of the weak ring
(1) The strength characteristics of the original yarn include average strength, strength unevenness, average elongation and elongation unevenness. The average strength of warp yarns is 15 cN/tex and the strength unevenness is about 9%-10%, while the average strength of weft yarns is 12 cN/tex and the strength unevenness is about 9%-10%. The average elongation at break is generally manipulated to be within 2%.
(2) air jet loom stopping the important strength indicator is strong weak ring that is low strength, it is generally believed that spinning yarn fineness is only 40% of the normal yarn, this detail weak ring must cause head breakage, resulting in stopping, if the strong weak ring in 4 cN / tex, elongation is less than 2%, will certainly cause head breakage.
(3) In addition to 61% of detail defects, other weak twists, bad joints, and rough knots also cause stoppage between warp and weft, accounting for about 39%.
(4) In addition to the average strength and uneven strength, the strong weak ring is an important factor to produce warp and weft yarn stoppage. According to the high-speed large-capacity power machine tensogiet detection of 100,000 weft broken head to deduce the possibility of spinning yarn purchase, so in a considerable size of knitted fabric, woven fabric factory on the strong requirements of the yarn to be very emphasis on the strong weak ring level, some relevant enterprises in China should be complete may be equipped with tensogiet strong instrument, to keep the quality of the original yarn.
(5) There are three main types of details on the original yarn: one kind of short pile details, one kind of coarse and fine nodes at the knot head, and another kind of filament nodes or multiple short details connected together can cause head breakage.
(6) In order to reduce the strong weak ring and provide good original yarn for the downstream process, corresponding measures must be taken, such as adopting the new roving machine with four-unit drive in the form of four-roller drafting, on the one hand, to remove the details caused by the switching car, on the other hand, to improve the drafting stem and reduce the coarse details of defects, etc., and also to strengthen the transmission of the drafting part of the key with the teeth, so that it does not have a loose gap, to ensure that the drafting process is synchronized, is also one of the important ways to reduce Details of one of the important methods.
In addition, the reasonable configuration of the process, the choice of good drafting parts, such as rubber rollers, rubber rings, up and down Xiao, pressure mechanism, etc. is also one of the factors to reduce the details.
Unevenness rate index contains two indicators: weight unevenness rate and strip unevenness rate, generally spinning mills pay more attention to unevenness rate, and the monitoring level is also high. Not much discussion here.
(1) The new double cotton box for cotton machine is to take the pressure sensor and frequency control motor to manipulate the density of cotton wool in the cotton box, so that the cotton layer fed into the card is consistent in the longitudinal and transverse direction, and the raw strip weight unevenness can be manipulated at 2% to 2.5%.
(2) In the card, the parallel machine, the combing machine and other pre-spinning equipment of each process open-loop, closed-loop and mixed-loop self-adjusting leveling mechanism are to improve the unevenness of yarn dryness and weight unevenness to play an active role.
(3) The drawing parts of the parallel machine such as rocker, roller, sleeve, etc. have been greatly improved, so that the unevenness of the short section has been greatly improved.
(4) The end of the strip with a coarse section monitoring device, coarse yarn equipped with tension monitoring system, to improve the yarn dry have a positive effect.
(5) Most of the spinning mills are equipped with off-line monitoring of the strip, monitoring frequency is high, timely detection of the strip and coarse details, the situation of cotton knot defects and timely solution.
(6) The advanced end-joining machine is equipped with online USTER self-adjusting leveling and monitoring system, which can monitor the strip dry level of the machine online and can generally cancel the offline monitoring.
(7) The implementation of a series of online and offline monitoring technology, so that the spinning quality has a good guarantee, generally can reach the level of 25% of the bulletin, some can reach within 5%.
Contact: Jeanne yang（MISS）
E-mail: [email protected]
Add: Room A2216/A2217,Double-Star Building,No 567 New South Middle Road, KunShan City JiangSu Province ,China.