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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.

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.

The purpose of this paper is to theoretically study the effects of ring spinning triangle division on spun yarn torques.

The case that the spinning triangle is divided into two parts, primary triangles and final triangle, is investigated. Theoretical model of yarn torque was given by linking the fiber tension in the spinning triangle to yarn torque under the assumption that the arrangement of fibers (substrands) in the substrands (yarn) is hexagonal close packing. Then, as an application of the proposed method, 14.6tex cotton yarns were taken as an example for the numerical simulations.

The fiber tensions in the divided spinning triangles and corresponding yarn torques were simulated numerically by using MATLAB software. The effects of division proportions and number of primary triangles on spun yarn torques are analyzed theoretically.

It is shown that suitable spinning triangle division is benefit for reducing yarn torque.

In order to develop high shape retention yarn and investigate the effects of spinning process and core yarn contents on the shape retention of yarn, in this paper, three kinds of yarns, JC/T400 18.5tex (55.6dtex) core-spun yarn, JC/T400 18.5tex (44.4dtex) core-spun yarn and JC18.5tex pure cotton yarn were spun by using the complete condensing Siro-spinning technology. The paper aims to discuss these issues.

In this paper, the core-spun yarns were spun by using the complete condensing spinning and Siro-spinning technology. Two key spinning processes, yarn twist factor and core yarn pre-draft ratio, were optimized by using the orthogonal test method first. Then, via the variable control method, the position of the core yarn, the position of the bell mouth and the center distance between two bell mouths were optimized, respectively, and corresponding optimal spinning process of the three yarns was determined. Finally, the yarns were spun under the optimal process, and the performance of the spun yarns was tested and compared.

Results show that the yarn twist factor affects yarn strength and hairiness, the position of bell mouth affects the evenness and hairiness of the yarn mainly, and the position of the core yarn affects the coverage and hairiness of the yarn. For the Z-twist spinning, the core yarn enters the front roller from the left side of two strands center, which is beneficial to improve the covering effect of core yarn, and reduce the pilling phenomenon of the yarn. The contents of core yarn affect indicators of the yarn shape retention, such as yarn strength, elastic recovery and abrasion resistance.

The shape retention of yarns affects the shape retention of fabrics, and the production of yarn with high shape retention is a key step in achieving shape retention of fabrics. At present, there are little studies on the shape retention of yarns, most researchers shave focused on shape retention of fabrics. Using the complete condensing Siro-spinning method to spin the core-spun yarn can improve the quality of the yarn. Compared with traditional ring-spinning yarns, the addition of the core yarn can improve the shape retention of the yarn.

With the popularization of electronic products, the electromagnetic radiation pollution has been the fourth largest pollution after water, air and noise pollution. Therefore, electromagnetic shielding property of textiles is attracting more attention. In this paper, the properties of electromagnetic shielding yarns and fabrics were studied.

Ten kinds of yarn, stainless steel short fiber and polyester blend yarn with three different blending ratios T/S 90/10, T/S 80/20 and T/S 70/30, stainless steel short fiber, polyester and cotton blend yarn with blending ratio C/T/S 35/35/30, core-spun yarn with one 30 um stainless steel filament C/T28tex/S(30 um), core-spun yarn with two 15 um stainless steel filaments (C/T28tex/S(15 um)/S(15 um)), twin-core-spun yarn with one 30 um stainless steel filament and one 50D spandex filament C/T28tex/S(30 um)/SP(50D), sirofil wrapped yarn with one 30 um stainless steel filament feeding from left S(30 um)+C/T28tex, sirofil wrapped yarn with one 30 um stainless steel filament feeding from right C/T28tex+S(30 um), sirofil wrapped yarn with two 15 um stainless steel filaments feeding from two sides S(15 um)+C/T28tex+ S(15 um), were spun. The qualities of spun yarns were measured. Then, for analyzing the electromagnetic shielding properties of fabrics made of different spun yarns, 20 kinds of fabrics were woven.

The tested results show that comparing to the T/S 80/20 blend yarn, the resistivity of composite yarns with the same ratio of the stainless steel filament is smaller. The possible reason is that comparing to the stainless steel short fiber, the conductivity of stainless steel filament is better because of the continuous distribution of stainless steel in the filament. Comparing with the core-spun yarn, the conductivity of the sirofil wrapped yarn is a little better. Comparing to the fabric woven by the blend yarn, the electromagnetic shielding of the fabric woven by the composite yarn is better, and comparing to the fabric woven by the core-spun yarn, the electromagnetic shielding of the fabric woven by the sirofil yarn is a little better. The possible reason is that the conduction network can be produced by the stainless steel filament wrapped on the staple fiber yarn surface in the fabric, and the electromagnetic wave can be transmitted in the network.

In this paper, the properties of electromagnetic shielding yarns and fabrics were studied. Ten kinds of yarn, including three stainless steel short fiber and polyester blend yarns, one stainless steel short fiber, polyester and cotton blend yarn, two core-spun yarns, one twin-core-spun yarn, three sirofil wrapped yarn, were spun. Then, for analyzing the electromagnetic shielding properties of fabrics made of different spun yarns, 20 kinds of fabrics were woven. The effects of fabric warp and weft densities, fabric structures, yarn kinds, yarn distributions in the fabric on electromagnetic shielding were analyzed.

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.

With the improvement of living standards and acceleration of working pace, the shape retention property of textiles has attracted more attention. Yarn spinning is the first fundamental process in making textiles and apparel, and the properties of yarn influence the performance of textiles directly. Filament/staple fiber composite yarn is a kind of yarn spun by filament and staple fiber, and comprehensive qualities of yarn can be improved. Therefore, the purpose of this paper is to study the shape retention properties of filament/staple fiber composite yarns and corresponding fabrics.

Four kinds of composite yarn, core-spun yarn with one 50D SPH filament feeding, sirofil wrapped yarn with one 50D SPH filament feeding from left, sirofil wrapped yarn with one 50D SPH filament feeding from right, sirofil wrapped yarn with two 25D SPH filaments feeding from two sides, were spun. The qualities of spun yarns were measured. Then, corresponding two kinds of twill fabrics were woven by core-spun yarn and sirofil wrapped yarn with two filaments, respectively. The handle parameters, crease recovery, appearance leveling after washing, dimensional change rate after washing, strength and elongation and tensile elasticity were tested by using corresponding test instruments.

The tested results of spun yarn qualities show that comparing with the core-spun yarn, the evenness of sirofil wrapped yarn is improved, the hairiness is reduced, and the breaking strength and elongation are increased. Comparing with sirofil wrapped yarn with one filament, the evenness of sirofil wrapped yarn with two filaments is improved. The measured results of fabrics properties show that under the same weaving process, comparing to the fabric woven by core-spun yarn, the dimension of fabric woven by sirofil wrapped yarn is small after desizing, and warp and weft density is large. The possible reason is that the shrinkage of the SPH filament outside the sirofil wrapped yarn happens after desizing, which also makes the dimensional change rate after washing of the corresponding fabric large, and crease recovery poor.

In the paper, for improving the shape retention properties of the pure cotton woven fabric, one kind of SPH filament was added to the woven fabric by spinning filament/staple fiber composite yarns. Four kinds of composite yarn, core-spun yarn with one 50D SPH filament, sirofil wrapped yarn with one 50D SPH filament feeding from the left side, sirofil wrapped yarn with one 50D SPH filament feeding from the right side, sirofil wrapped yarn with two 25D SPH filaments feeding from two sides, were spun. Two kinds of twill fabrics were weaving by core-spun yarn and sirofil wrapped yarn with two filaments, respectively.

Ring spinning is the most widely used spinning method at present. In the spinning, ring and traveller are the two important components of the twisting process. The properties of ring and traveller have a direct relationship with the yarn qualities and spinning speed. Therefore, the purpose of this paper is to study the mutual relationships of flange ring and traveller system by taking the 6802-type traveller with rectangular structure, BU-type traveller with toxoplasma structure and 772-type traveller with corrugated structure as examples.

First, the theoretical calculation models of force and inclinations of the traveller are given, and calculation methods of corresponding key parameters referred in the models are presented. Then, by using SolidWorks software, models of the three kinds of traveller straddling on the PG1-4254 type ring are built, and the traveller and ring are simulated by using ADAMS software. By using MATLAB software, the force and inclinations of the traveller during the rotation around ring are simulated. Finally, the spinning experiments are made.

It is shown that the abrasion of 6802-type traveller is the most serious, and corresponding yarn evenness and hairiness is the worst. The abrasion of BU-type traveller is the slightest, and corresponding yarn evenness is the best. The yarn spins by using 772-type traveller has the least hairiness.

In the paper, the mutual relationships of flange ring and traveller system have been studied. For giving analysis of force and inclinations of the traveller, calculation methods of the key common parameters are presented. By using SolidWorks software, the physical models of the three kinds of traveller straddling on the PG1-4254 type ring are built. And then, the force and inclinations of the traveller during the rotation around ring are simulated by using MATLAB software. At last, the spinning experiments are made to analyse the simulation results.

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.

Through the tracer fiber method, we strive to more accurately obtain the hook degree, straightening degree, percentage and other characteristic indexes. In order to intuitively represent the hook state from sliver to yarn, and feed back production information in combination with quality test.

Taking the cotton fiber as an example, the hooked fibers were studied by using the tracer fiber method. Tracer fibers were made from cotton-type viscose fibers. Tracer fibers and combed cotton fibers were uniformly mixed for many times and used to produce the card sliver, semi-drawn sliver, drawn sliver, roving and yarn. With the help of ZF-20D ultraviolet analyzer, geometric parameters of hooked fibers were measured, and characterization indexes were calculated. And hook indexes and quality indexes were compared.

By redefining and reclassifying hooked fibers, the change of hooked fibers in the process was tracked and characterized carefully. Some hooks in card sliver are straightened but not eliminated, and will form longer zero-angled hooks in the subsequent process. The straightening degree and number of zero-angled hooks affect the evenness CV mainly.

The characterization of hooked fibers is important for reducing hooked fibers and spinning high quality yarns. There is no uniform standard for the characterization of hooked fibers at present. Most studies are about relationship between process and hook in carding and drawing. There is no research on hooked fibers in the whole spinning process. In the paper, hooked fibers were redefined and reclassified, the change of hooked fibers in the process was tracked and characterized carefully.