CN1818167A - Method for decreasing flock/wave netting drawing - Google Patents

Abstract

The invention discloses a method for reducing the drafting wave of short fiber bundles/webs, which mainly adopts high-frequency vibration on the fiber bundles/webs in the drafting area composed of rollers to eliminate the drafting waves from the level of the drafting wave generation mechanism stretching waves. It can be widely used in spinning equipment such as drawing frame, needle carding, roving, spun yarn, etc. It can effectively reduce or eliminate drafting waves, improve the drafting performance of fiber bundles, reduce processes, and reduce the downtime rate of subsequent processes, thereby improving productivity. Improve yarn and textile quality.

Description

A method of reducing the drafting wave of short fiber bundle/web

Technical field:

The present invention relates to a method for reducing the drafting wave of short fiber bundles/webs, in particular to a method for reducing the drafting waves of short fiber bundles/webs by using high-frequency vibrations.

Background technique:

Drafting mainly occurs in processes such as drawing, carding, roving, and spinning. Drafting is the process of drawing and thinning continuous short fiber bundles (commonly known as "shafts"). Drafting causes the relative displacement of the fibers in the axial direction of the sliver, so that the fibers are distributed over a longer length. The purpose is to draw the spun sliver and improve the parallel straightness of the fibers.

A typical drafting method is roller drafting. The roller drafting device usually includes multiple pairs of rollers. Each pair of rollers forms a holding point for the strands. The speed of each pair of rollers becomes faster and faster along the direction of fiber conveying. A drafting zone is formed between the two holding points. When there is a relatively large relative speed between the two holding points, and the external force is sufficient to overcome the friction and cohesion between the fibers, relative movement occurs between the fibers, and the strands are drawn and thinned, thereby realizing the drafting of the fiber bundles.

However, due to the different lengths of the short fibers that make up the strands (even for artificial staple fibers of uniform length, the projected lengths of each fiber in the length direction of the fiber bundle are also different), the shorter fibers cannot be fully grasped by the drafting roller. These short fibers are called "planktonic fibers" and their movement during drafting is uncertain. The planktonic fibers usually move together in bundles, causing irregularities in the drafting of the fiber bundles, which we call "drawing waves". The drafting wave is inherent in roller drafting, which directly leads to unevenness of the sliver after drafting and affects the quality of subsequent yarns and textiles.

In order to improve the performance of the roller draft, people have studied various factors affecting the roller draft, such as the surface material of the roller [Taylor, R.A. and Graham, J.S., The Influence of Front-Roll Coverings on the Spinning Strength of Cotton, TextileRes .J.49, 717-723(1979).], Surface Texture of Roller [Plonsker, H.R.; Backer, S.Dynamics of roller drafting.II.Role of fiber crimp in the tensile behavior of slivers at low drafts or strains.TextileResearch Journal(1969), 39(9), 823-30.], Irregularity of yarns [Mahmoudi, M.R., Dobb, M.G., The Effect of the Spinning Process on Wool-fiberCrimp, J. Textile Inst., 87, 597-598(1996).], twist of roving [Plonsker, H.R.; Backer, S..Dynamics of roller drafting.I.Drafting ForceMeasurement.Textile Research Journal(1967), 37(8), 673-687.], Fiber finish [Korkmaz, Y.A. and Behery, H., "Relationship between fiber fineness, break draft, and drafting force in rollerdrafting", Textile Res.J.74(5), 405-408, 2004.], etc. People have also analyzed and tested the relevant process parameters of roller drafting. For example, Liu Guotao discussed the problem of improving the quality of roving drafting from the perspective of the relationship between drafting type, drafting components, drafting transmission, drafting process and drafting quality. [Journal of Wuxi Institute of Light Industry, 1992, pp. 77-88 of the first issue, pp. 162-168 of the second issue]; Wu Yuqun discussed the influence mechanism of the key factors of the spun yarn drafting system on the yarn quality [Journal of Donghua University, vol. 31, 112 -116 pages]; Lu Hengzheng briefly analyzed the theory of drawing and drawing and its application [Textile Herald, 1995 Fifth Issue 55-61 pages] and so on.

In addition, people have designed intermediate control parts to generate additional friction force circles so that the entire friction force circle is close to the theoretical requirements, hold (hold) and stably transport the yarn forward, maintain a certain strength (tension) of the yarn, and make the entire yarn Enter the front jaw in a straightened state, and keep the strands at an appropriate density to prevent the fibers from spreading. Intermediate control components such as lightweight rollers, aprons, and needle rollers are generally used on spinning frames; intermediate control components such as air (inflatable) rollers, lightweight rollers, needle plates, and needle rollers are generally used on roving frames; Intermediate control components such as needle plate, needle roller, sawtooth roller, and pressure bar are used. Although these methods can improve the drafting to a certain extent, the drafting wave problem is still a difficult problem affecting the drafting quality of the sliver, and the drafting wave needs to be eliminated by a new method.

In the drafting zone shown in Figure 1, some fibers (such as a and c) may be controlled by the grip of the rollers, and other fibers (such as b) may be in a "floating" state, and the movement of floating fibers is controlled by the adjacent The effect of the friction applied by the fibers. If the surface material of the rollers is selected correctly, the diameter of the rollers, the pressure of the upper rollers, the control of the lateral distribution of the fiber bundles, the movement of the fibers held by the rollers (a and c) is generally predictable, while the floating fibers (b) Movement is unpredictable. Since the planktonic fibers are surrounded by the surrounding fibers, some fibers move at a faster speed (V2) during the period, and the fast-moving fibers exert forward friction on the planktonic fibers, so that fiber b accelerates forward; while some other fibers and planktonic fibers Fibers b move together at a slower speed (V1), and these fibers exert friction on the planktonic fibers, preventing the planktonic fibers from accelerating forward, creating a tendency to pull back. All these external forces are formed by the friction of the fiber surface.

The main cause of the drawing wave is the friction force between fibers and the cohesion force caused by fiber curl, especially the difference between the coefficient of static friction (μs) and the coefficient of dynamic friction (μd). Many scholars have studied the friction properties of fibers [J.H.Langston, Textile Research Journal, 643-653, July1954; H.G.Howell "Friction in Textiles", Textile Book Publishers, Inc.London, 1959; B.J.Briscoe, Textile Research Journal, 697-708 , Dec.1990; W.F.du Bois, Textile Research Journal, v.29, 451-466, June 1959; Murayama, Journal of Applied Polymer Science, v.24, 1413-1417, 1979.], it is generally accepted that the static coefficient of friction of fibers μs is greater than the dynamic friction coefficient μd of the fiber, and the difference between the dynamic friction coefficient and the static friction coefficient is the main cause of the "stick-slip" movement.

Invention content:

The technical problem to be solved by the present invention is to provide a method for reducing the drafting wave of the short fiber bundle/net, so as to solve the defects of the prior art.

To make the drawn fiber bundle as uniform as possible, the ideal situation is: once the fiber reaches a certain position in the drafting zone, the fiber can be gripped and accelerated by the fast roller, and overcome the static friction of the surrounding fibers. To pull (detach) from surrounding fibers. On the other hand, some fibers around it are also floating fibers. Since the coefficient of static friction μs > the coefficient of dynamic friction μd, once the slip begins, the frictional force preventing relative sliding becomes smaller. It is easy to cause other planktonic fibers to move together, rather than each alone, causing irregularity in fiber movement, thereby generating stretching waves.

Based on the above analysis, Wooden Invention proposes to apply high-frequency and low-amplitude vibration to the fiber bundle/network in the drafting area, so that high-frequency tiny relative motions will be generated between the fibers in the drafting area, and the friction between the fibers will be reduced. In the state of dynamic friction, or dominated by dynamic friction rather than static friction, then the fiber binding effect that causes the drafting wave will be significantly reduced or eliminated, thereby avoiding the "stick-slip" effect and making it gripped by the front roller The fibers can be drawn more easily independently from the surrounding fibers, effectively eliminating the drafting waves.

The purpose of the present invention is to provide a method for reducing the drafting wave of short fiber bundles/networks. In this method, two pairs of rollers form a drafting zone, so that the speed V1 of the holding point of the front roller 1 and the front roller 2 is greater than that of the rear roller. The key to the speed V2 of the holding point of roller 3 and rear roller 4 is:

Vibration is applied to the fiber bundle/web in the drafting zone;

The frequency range of the vibration is 50-3000 Hz, and the amplitude range of the vibration is ±0.1-±1.5 mm;

Wherein, the direction of vibration and the direction of fiber bundle/network drafting movement form an included angle of 60°-120°, and the preferred included angle is 90°.

Wherein the vibration can be realized by the vibrator 6 or the sound wave generator 12 .

The vibration frequency and amplitude of the vibrator 6 described therein are adjusted by the vibrator controller 7; when the vibrator 6 is used to vibrate, the preferred vibration frequency is 100-800 Hz, and the amplitude range is ± 0.2～±1mm.

The vibration frequency and amplitude of the sound wave generator 12 described herein are regulated by the sound wave generator controller 13; 0.1～±0.6mm.

Wherein the vibrator 6 can apply vibration to the fiber bundle/net through the intermediate control part 5 in the drafting zone; or directly apply vibration to the front roller 1, thereby applying vibration to the fiber bundle/web;

The above-mentioned intermediate control member 5 is an apron, a pressure bar, a lightweight roller, a needle roller or a needle plate.

The vibrator 6 can be directly connected and fixed with the intermediate control part 5, or directly contacted with the intermediate control part 5 to achieve the purpose of implementing vibration.

The exciter is a product widely used in industry and other fields, such as the JZ series exciter produced by Beijing Jingyi North Instrument Co., Ltd.

Acoustic generators are products widely used in industry and other fields, such as the LAG-26 audio signal generator produced by Lida Company of Japan, the VP-725A audio signal generator produced by Panasonic Company of Japan, etc.

The intermediate control part 5 is an apron, a pressure bar, a light roller, a needle roller or a needle plate. These intermediate control components are widely used in the textile field, such as:

√The FA306 draw frame of Shenyang Hongda Textile Machinery Co., Ltd. and the FA313 series draw frame of Shaanxi Baocheng New Textile Machinery Co., Ltd. both use pressure rods as the intermediate control parts of the drafting mechanism of the draw frame.

√The A454 series roving frame of Tianjin Hongda Textile Machinery Co., Ltd. and the JF type spun yarn drafting mechanism developed by Kunshan Jingfeng Machinery Co., Ltd. of Jiangsu Province use aprons as intermediate control components.

√The FB441 roving frame of Wuxi No.7 Textile Machinery Co., Ltd. adopts lightweight rollers.

√The FA900 needle carding machine of Lianyungang Yingyou Textile Machinery Co., Ltd. uses the needle roller as the intermediate control part.

√The B432 wool spinning needle carding machine of Zhejiang Golden Eagle Co., Ltd. and the B302-B442 wool spinning needle carding machine of Jiangyin Baishun Technology Co., Ltd. use the needle plate as the intermediate control part.

This method applies appropriate vibration to the fiber bundle/network in the drafting area, so that high-frequency micro-relative motions are generated between the fibers in the drafting area, so that the friction between the fibers is in a state of dynamic friction, then, resulting in a draft wave The "stick-slip" effect is significantly reduced or eliminated, thereby effectively eliminating the drafting wave, the drafting force is more stable, and the uniformity of the short fiber bundle/web is improved.

If the frequency of the applied vibration is higher and the amplitude is larger, the high-frequency relative motion between fibers will be intensified. When this high-frequency relative motion exceeds a certain limit, the drafting force required by the drafting process will be significantly reduced. , thereby affecting normal drafting; if the frequency of the applied vibration is lower, the amplitude is smaller, and the high-frequency relative motion between fibers is weakened. When this high-frequency relative motion is weakened to a certain extent, the effect of vibration It is not obvious, so the draft wave cannot be eliminated. In addition, this method can be used in various equipment such as drawing frame, needle carding frame, roving frame, spinning frame, etc. The specifications of short fiber bundles/nets drafted by various equipment are quite different. Different degrees of vibration need to be applied to the net, therefore, the frequency and amplitude of the applied vibration should be able to be adjusted online.

Advantages of the present invention:

The invention eliminates the drafting wave from the level of the drafting wave generation mechanism. It is a general technology for the drafting of short fiber bundles and can be widely used in textile equipment such as drawing frames, needle combs, rovings, and spun yarns. It can effectively Reduce or eliminate the drafting wave, improve the drafting performance of the fiber bundle, reduce the process and reduce the shutdown rate of the subsequent process, thereby increasing the productivity and further improving the quality of the yarn and textiles. The present invention is suitable for an independent module design, can be applied to the development of related new textile machinery, and can also be used to transform and update existing equipment, is convenient for implementation and popularization, has a good application prospect, and is expected to produce more Good economic benefits.

5. Description of drawings

Fig. 1: Drafting zone with two pairs of rollers

Figure 2: Vibration of intermediate control components with a vibrator

Figure 3: Direction of applied vibration

Figure 4: Vibrating the apron part with a vibrator

Figure 5: Vibrating the pressure bar with a vibrator

Figure 6: Sonic vibrations applied to the fiber bundle/web in the drafting zone

Figure 7: Application of acoustic vibrations to a fiber bundle/web controlled by an intermediate control component

Figure 8: Exciting the front roller with a vibrator

Among them, front roller 1, front roller 2, rear roller 3, rear roller 4, intermediate control part 5, vibrator 6, vibrator controller 7, apron 8, apron 9, lower supporting plate 10, pressure rod 11. Sound wave generator 12, sound wave generator controller 13, front roller seat 14.

6. Specific implementation

1. The way the apron vibrates

As shown in Figure 4, there are two pairs of rollers forming a drafting area, and the speed V1 of the front rollers 1 and 2 is greater than the speed V2 of the rear rollers 3 and 4. Aprons 8 and 9 are installed in the drafting zone as intermediate control elements. Aprons 6 and 7 are driven by back rollers 3 and 4 respectively. Aprons 8 and 9 are in direct contact with the staple fiber bundle/web and control the movement of the staple fiber bundle/web. The positions of the aprons 8 and 9 are adjustable.

The lower supporting plate 10 of the apron 9 is vibrated by the vibrator 6 to make the apron 9 vibrate. The vibration period and amplitude of the exciter 6 can be adjusted by the exciter controller 7, so the vibration frequency and amplitude applied to the fiber can be adjusted, the frequency is 400 Hz, and the vibration amplitude is ±0.5 mm. The vibrating contact of the vibrator 6 is directly connected to the end of the lower supporting plate 10, and the direction of the vibration of the vibrator 6 is about 90° with the direction of the fiber bundle/net drafting movement, as shown in Figure 3 .

2. The way the pressure bar vibrates

As shown in Figure 5, there are two pairs of rollers forming a drafting area, and the speed V1 of the front rollers 1 and 2 is greater than the speed V2 of the rear rollers 3 and 4. A pressure bar 11 is installed in the drafting zone as an intermediate control element. The pressure bar 11 is in direct contact with the staple fiber bundle/web and controls the movement of the staple fiber bundle/web. The position of the pressure bar 11 is adjustable.

Vibrator 6 is used to vibrate the pressure bar 11 to make it vibrate. The vibration period and amplitude of the exciter 6 can be adjusted by the exciter controller 7, so the vibration frequency and amplitude applied to the fiber can be adjusted, the frequency is 500 Hz, and the vibration amplitude is ±0.7 mm. The vibrating contact of the vibrator 6 can be directly connected to the end of the pressure rod 11 , and can also be directly pressed on the pressure rod 11 . The included angle between the vibration direction of the vibrator 6 and the direction of the fiber bundle/web drafting movement is about 90°, as shown in FIG. 3 .

3. The way of sonic vibration without intermediate control parts

As shown in Figure 6, there are two pairs of rollers forming a drafting area, and the speed V1 of the front rollers 1 and 2 is greater than the speed V2 of the rear rollers 3 and 4. The distance between the two pairs of rollers is relatively small (approximately equal to the length of the longest fiber in the fiber bundle), and there are no intermediate control elements in the drafting zone.

Aim the fiber bundle/web in the drafting zone with the bell mouth of the acoustic wave generator 12, and vibrate the fibers in the drafting zone. The vibration frequency and amplitude of the acoustic wave generator 12 can be adjusted by the acoustic wave generator controller 13, so the frequency and amplitude of the vibration applied to the fiber can be adjusted. The frequency is 2200 Hz and the amplitude is ±0.3 mm. The angle between the vibration direction of the sound wave and the direction of the fiber bundle/web drafting motion is about 90°, as shown in FIG. 3 .

4. There is a way of sound wave vibration of intermediate control parts

As shown in Figure 7, there are two pairs of rollers forming a drafting zone, the speed V1 of the front rollers 1 and 2 is greater than the speed V2 of the rear rollers 3 and 4, and there is a pressure bar as an intermediate control component in the drafting zone.

In the direction of the fiber bundle/web that is not blocked by the pressure bar, the bell mouth of the acoustic wave generator 12 is aimed at the fiber bundle/web in the drafting zone, and vibration is applied to the fibers in the drafting zone. The vibration frequency and amplitude of the acoustic wave generator 12 can be adjusted by the acoustic wave generator controller 13, so the frequency and amplitude of the vibration applied to the fiber can be adjusted, and its frequency range is 2200 Hz, and the amplitude range is ±0.4 mm . The angle between the vibration direction of the sound wave and the direction of the fiber bundle/web drafting motion is about 90°, as shown in FIG. 3 .

5. The way the front roller vibrates

As shown in Figure 8, there are two pairs of rollers forming a drafting zone, and the speed V1 of the front rollers 1, 2 is greater than the speed V2 of the rear rollers 3, 4. Make the front roller 1 vibrate with the exciter 6, the vibration period and the amplitude of the exciter 6 can be adjusted by the exciter controller 7, so the vibration frequency and the amplitude of the front roller 1 are adjustable, so for The frequency and amplitude of the vibration applied to the fiber are adjustable, the frequency range is 500 Hz, and the vibration amplitude range is ±0.6 mm.

The vibration contact of vibrator 6 is directly connected to the roller seat 14 of front roller 1, and the angle between the direction of vibration and the direction of short fiber bundle/net drafting motion is about 90 °, as shown in Figure 3.

Claims (9)

1. method that reduces staple fibre bundle/net drafting wave, this method is formed a draw zone by two pairs of rollers earlier, makes speed V1 that front roller (1), (2) grip point greater than the speed V2 that rear roller (3), (4) grip, it is characterized in that:

Fibre bundle/the net that is in draw zone is applied vibration;

Wherein Zhen Dong frequency range is 50～3000 hertz, and the amplitude range of vibration is ± 0.1～± 1.5 millimeter;

Wherein the direction of Zhen Dong direction and fibre bundle/net stretch exercise is 60 °～120 ° angles.

2. method according to claim 1 is characterized in that vibration can realize by vibrator (6) or sonic generator (12).

3. method according to claim 2 is characterized in that the vibration frequency of described vibrator (6) and amplitude are to regulate by vibrator controller (7).

4. method according to claim 3, the frequency that it is characterized in that described vibration is 100～800 hertz, amplitude range is ± 0.2～± 1 millimeter.

5. method according to claim 2 is characterized in that the vibration frequency of described sonic generator (12) and amplitude are to regulate by sonic generator controller (13).

6. method according to claim 5, the frequency that it is characterized in that described vibration is 1000～2500 hertz, amplitude range is ± 0.1～± 0.6 millimeter.

7. method according to claim 3 is characterized in that described vibrator (6) applies vibration by the middle control assembly (5) of exciting draw zone to fibre bundle/net; Or directly front roller (1) is applied vibration, thereby fibre bundle/net is applied vibration;

Control assembly (5) is apron, pressure bar, light top roller, porcupine roller or needle plate in the middle of wherein said.

8. method according to claim 7 is characterized in that vibrator (6) directly is connected and fixed with middle control assembly (5), or directly contacts with middle control assembly (5).

9. method according to claim 1 is characterized in that the direction of described vibration and the direction of fibre bundle/net stretch exercise are 90 ° of angles.

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