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The purpose of this study is to investigate the effects of air-suction slots geometry on the condensing zone of pneumatic compact spinning.

This paper investigated the condensing zone of pneumatic compact spinning with perforated drum for different structures of air-inlet slot geometry with computational fluid dynamics. For this purpose, three air-suction guides with different air-slots were designed. To create the condensing zone for the numerical simulation, a suction insert and the perforated drum were also designed. Flow velocity components on the X, Y, and Z axes, static pressure distribution and the streamline diagram were used for comparative analysis. Designed air-suction guides were produced with a 3D printer and used for yarn production.

Numerical simulation results showed that condensing effects were provided for all three types of air-suction guides and approaching air-slots on the suction guides resulted in greater flow components but may cause fluctuations. Experimental results also showed that actual flow velocity components (Z-axis) are effective on hairiness (H) properties of the yarn while assisting flow-velocity components are more effective on the evenness and tenacity properties of the yarn.

This paper presents the numerical flow field simulation of compact spinning for different structures of air-suction guides with detailed measurements. To know the effects of air-suction guides on the condensing zone may be helpful to improve yarn properties. In addition, a 3D printer was used for the production of designed parts.

Pneumatic compact spinning is the most widely used compact spinning method at present, in which the negative pressure airflow is used to condense the fiber in order to decrease the spinning triangle and improve the yarn qualities. Therefore, the research on flow field in the condensing zone is always the emphasis for pneumatic compact spinning. The paper aims to discuss these issues.

By using finite element method (FEM), the flow field in two kinds of pneumatic compact spinning was studied. Taking three kinds of cotton yarns as examples, with the help of high-speed camera system OLYMPUS i-SPEED3, the motion trajectory of fiber strand in the condensing zone was obtained. Three-dimensional physical models of the condensing zone of the two compact spinning systems were obtained according to the measured parameters of practical spinning systems.

It is shown that on the both left edge of B1 line and right edge of B2 line, the airflow inflows to the center line of suction slot, and the condensed effects are produced, correspondingly. In the condensing zone, there are three condensing processes acting on the fiber strand, including the rapid condensing effects in the front condensing zone, the adequately condensing effects in the middle condensing zone, and stable output effects in the back condensing zone.

By using FEM, numerical simulations of three-dimensional flow field in condensing zone for two kinds of pneumatic compact spinning with lattice apron were presented, and corresponding spun yarn qualities were analyzed.

Pneumatic compact spinning is the most widely used compact spinning method at present, in which the negative pressure airflow is used to condense the fiber bundle and decrease the spinning triangle. Compact spinning with perforated drum and lattice apron are mainly two kinds of pneumatic compact spinning now. The purpose of this paper is to study the comparative analysis on four kinds of pneumatic compact spinning systems, including two kinds of compact spinning with perforated drum: Rieter’s COM4 and complete condensing spinning (CCS), two kinds of compact spinning with lattice apron: Sussen’s three-line compact spinning (TLCS) and Toyota’s four-line compact spinning (FLCS).

First, the basic properties of four systems were introduced and comparatively analyzed. Then, the 29.2 tex (20S), 14.6 tex (40S), 9.7 tex (60S) and 7.3 tex (80S) combed cotton yarns were spun in the four pneumatic compact spinning systems and ring spinning system, respectively. The evenness, breaking strength and hairiness of spun yarns were tested. Finally, the properties of corresponding woven fabric were tested.

It is shown that comparing to compact spinning with lattice apron, the disposable input cost of compact spinning with perforated drum is higher, but the maintenance cost is lower. Comparing to compact spinning with lattice apron, the evenness of yarn spun by compact spinning with perforated drum is improved whereas the breaking strength is decreased. Furthermore, although harmful long hairiness (=3 mm) of yarn spun by CCS is a little more, the beneficial short hairiness (1-2 mm) is also more, which can make the fabric fullness and have better comfortable feeling.

In the paper, comparative analysis on four kinds of pneumatic compact spinning systems, compact spinning with perforated drum: Rieter’s COM4 and CCS, and compact spinning with lattice apron: Sussen’s TLCS and Toyota’s FLCS, were studied. The basic properties, spun yarn qualities and properties of corresponding woven fabric of four systems were analyzed comparatively.

As one natural fiber, spun silk is one of the top-grade textile materials and has attracted more and more attentions on textile processing. The purpose of this paper is to introduce one kind of pneumatic compact spinning, four-line compact spinning (FLCS), into the silk spinning, and study and comparatively analyze corresponding yarn and fabric qualities.

First, two kinds of spun silk and viscose blend yarns, 120 Nm (8.3 tex) and 205 Nm (4.9 tex), were spun on the common ring spinning frame FK501 and spinning frame modified by FLCS, respectively. Then, after the plying and singeing procedures, the ply yarns 120 and 205 Nm/2 were produced. The evenness, breaking strength, and hairiness of the spun bobbin yarns and ply yarns were tested and comparatively analyzed. Then, properties of corresponding woven fabric, including the weight, thickness, permeability, stiffness, softness, smoothness, draping, wrinkle recovery, hand-touching (RHV), were measured and comparatively analyzed.

For the spun yarns, it is shown that by using the compact spinning method, the comprehensive quality of spun-silk blend bobbin and ply yarns are improved. For the fabrics, it is shown that compared with the fabric made of ring yarn, the weight and thickness of fabric made of compact yarn decreased, and the air permeability of fabric increased, but the difference is tiny. Meanwhile, the stiffness, smoothness of fabric made of compact yarn increased slightly, but the softness decreased slightly, leading to a little worse fabric hand-touching.

In the paper, one kind of pneumatic compact spinning, FLCS, was introduced into the silk spinning, and corresponding yarn and fabric qualities were studied and comparatively analyzed.

Condensing roller is the most key parts of compact spinning system. Hollow Roller is one of the most important kinds of condensing roller, the surface structure of which influences the flow field in condensing zone directly and affects the qualities of spun yarn. The purpose of this paper is to study the effect of Hollow Roller surface structure on flow field in condensing zone is investigated by using Fluent Software.

In this paper, the effect of Hollow Roller surface structure on flow field in condensing zone is investigated by using Fluent Software. The numerical simulations of the three-dimensional flow field in Hollow Roller compact spinning with two different kinds of roller surface structure, round hole structure and strip groove structure, are given according to the three-dimensional physical model of condensing zone. The flow velocity and static pressure distributions in condensing zone are given.

It is shown that the flow velocity streamline distribution is denser with strip groove structure than that of round hole structure, especially on the center line of strand, and flow velocity value is also larger in both Y-Z and X-Y cross-sections, and in X-Z cross-section shows the embracing inlet airflow, which is benefit for fiber condensing directly and improving negative pressure use efficiency. Furthermore, the simulations with three strip groove widths 0.4, 0.8 and 1.2 mm are given. The theatrical results obtained are illustrated by experiments.

In this paper, the effect of Hollow Roller surface structure on flow field in condensing zone is investigated by using Fluent Software in detail. A more accurate three-dimensional physical model of condensing zone is given. A new kind of strip groove structure of Hollow Roller is proposed. The theatrical results obtained are illustrated by experiments, and lay a foundation for practical Hollow Roller design.

The purpose of this paper is to know airflow field and its distribution of pneumatic compact spinning systems. Complete compact spinning (CCS) and four-line rollers compact spinning (FRCS) are both two kinds of pneumatic compact spinning systems, which utilizes airflow in condensing equipment to condense fiber bundle and improve yarn properties.

The paper opted for an exploratory study using finite element method, the airflow field in the condensing area of CCS and FRCS were simulated. First, a periodic movement of the fibers in bundle in condensing area was detected, and the yarn tracks were described veritably under the high-speed-video-camera and AutoCAD Software. Then the physical models of the condensing zone were constructed according to the physical parameters of the practical system. The simulation of airflow velocities were extracted along the yarn tracks using ANSYS Software. Finally, the numerical results were verified by spinning experiments.

The results show that the negative velocity component along the Y-axis helps keeping beneficial hairiness. CCS has higher negative velocity value and more abundant beneficial hairiness than FRCS. The velocity component in the X-axis direction has a direct effect on yarn evenness. For the same liner density of CCS and FRCS, the larger the value of the velocity component on X-axis is, the better the yarn evenness is. For 9.7tex, CCS has larger velocity component in the X-axis direction and better yarn evenness than FRCS, showing that CCS is more suitable for spinning fine count yarn. The velocity component in the Z-axis direction has a direct effect on breaking strength. CCS has little velocity component in the Z-axis direction and little breaking strength than FRCS.

To know airflow field and its distribution by finite element method is helpful to investigate the condensing principles of the fiber bundle and improve yarn properties.

Spun silk is one of the top grade textile materials, and its products have high added value and meet the needs of the market. However, the technology level and process design of silk spinning are still much lower than cotton spinning; especially singeing is applied on spun silk yarn, and generates waste materials. The purpose of this paper is to introduce a kind of pneumatic compact spinning, four-line compact spinning (FLCS), into silk spinning and study the corresponding spun yarn qualities.

First, taking the silk spinning frame FK501 as an example, the process of modification of FLCS is presented. Then, three kinds of spun silk yarns, 80 Nm (12.5tex), 100 Nm (10tex) and 120 Nm (8.3tex), are spun on the common silk spinning frame FK501 and the spinning frame modified with FLCS. The evenness, breaking strength and hairiness of spun yarns are tested and comparatively analyzed. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.

The results show that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. Compared with the single spun silk yarn, the comprehensive qualities of the ply yarn are improved; especially, the breaking strength of the ply yarns is two times larger than the single yarn. After singeing, the hairiness of the ply yarn is decreased greatly, and the evenness is also improved, while the strength is decreased. Compared with ring spun silk yarn, the singeing times of compact spun silk yarn can be decreased, and the gas consumption in each singeing is also decreased, which is beneficial for material saving.

In this paper, a kind of pneumatic compact spinning, FLCS, is introduced into the silk spinning. It is shown that compared with ring spun silk yarns, the comprehensive quality of compact spun silk yarns is improved, especially the harmful long hairiness (=3 mm) of yarn. After the ply yarn production, three singeing procedures should be applied on the ring ply yarns, while only two singeing procedures should be applied on the compact ply yarns, which is beneficial for material saving.

As a natural fiber, yakwool has attracted much attention in textile processing due to its excellent properties and wearabilities. However, the main colors of yakwool are black and brown. Therefore, for extending the application scopes of the fiber, the decolorization of the yakwool fiber is usually needed, especially for the black fiber. The paper aims to discuss this issue.

In the paper, the properties of the yakwool fiber were tested first, especially the melanin granules in the fiber. Then, the decolorization of the yakwool fiber was studied using the oxidation–reduction decolorization method, and corresponding optimal process of the decolorization was given. Then, the properties of the decolorized yakwool fiber were tested and compared with those of the original fiber.

It is shown that, after decolorization, the physical and mechanical properties of the fiber were deteriorated, especially in terms of the strength and elongation. Therefore, the fiber became shorter and thinner, and the scales were damaged. When compared with the yarn spun from the original yakwool fiber, it was observed that the properties of the yarn spun from the decolorized yakwool fiber deteriorated because of the deterioration in the properties of the original fiber.

In the paper, for extending the application scopes of the yakwool fiber, the decolorization of the yakwool fiber was studied.

Sewing thread plays an important role in transforming a two-dimensional fabric into three-dimensional garment. Over the years, ring spinning has been dominating the yarn market because of its consistent performance. Eli-Twist spinning system, a new method of yarn manufacture, provides a product with improved mechanical and physical properties than the conventional ring-spun yarn. It is the process of producing a two-ply compact yarn with improved fibre utilisation. The purpose of this paper is to assess the feasibility of using Eli-Twist yarn as a sewing thread and to compare its performance with conventional thread.

In this study, regular polyester and Indian cotton were used to produce the Eli-Twist and conventional TFO thread. Three different blends (100 per cent polyester, 50/50 polyester/cotton [P/C] and 100 per cent cotton) were taken to produce three different counts (39.4 tex, 29.5 tex and 23.6 tex) from each composition. The hairiness, tenacity, breaking elongation and coefficient of yarn-to-metal friction of threads were tested and a comparative analysis was made. The seam performance of all the threads was judged by seam strength, seam efficiency and seam elongation.

The results show that the mass irregularity and imperfections are more or less similar for both types of threads. Eli-Twist sewing thread has shown less friction, less hairiness and higher tensile strength. The Eli-Twist sewing thread was found to be better than the conventional two-ply sewing thread. The seam performance parameters, such as seam strength, seam efficiency and seam elongation of the Eli-Twist thread showed significantly improved performance.

The main concern of this study is delineating the performance of the Eli-Twist sewing thread. No study in this regard has been reported so far. The improved physical and mechanical behaviour of the Eli-Twist yarn has prompted to assess its performance as sewing thread.

As one kind of filament/staple fiber composite yarn, core spun yarn has been widely used, especially on Jeans. However, there is only one filament in the commonly used core spun yarn, such as spandex, and the performance of the one filament often is influenced during dyeing and finishing. Therefore, in the paper, twin-core spun yarns with two different filaments feeding simultaneously were spun on ring spinning frame modified by one kind of filament feeding numerical control device. The paper aims to discuss these issues.

Four kinds of twin-core spun yarns, cotton/spandex/PBT, cotton/spandex/CM800, cotton/spandex/T400, cotton/spandex/SPH with linear density 36.4tex/40D/50D were spun. For improving the covering effect of the two filaments, the filament feeding position, filament pre-drafting multiple, distance between two staple roving, designed twist factor of the core spun yarn were optimized.

It is shown that comparing with the core spun yarn, the breaking strength and elongation of the twin-core spun yarns are improved since the addition of another elastic filament, while the evenness is a little worse.

By using the twin-core spun yarns, corresponding knitted and woven fabrics are produced. Meanwhile, for simulating the dyeing and finishing process, the knitted fabrics were treated during the 150°C high temperature. It is shown that comparing with the fabrics produced by cotton/spandex yarn, addition of another elastic filament can improve the fabric strength and resistant and has positive effect on worsen prevention for high temperature treated fabric elastic recovery, and on change prevention during the dyeing and finishing process for fabric handle properties, and improves the fabric stability.