Chunping Xie

Theoretical study of fiber tension distribution at the spinning triangle

The spinning triangle is a critical region in the spinning process of yarn. Its geometry influences the fiber tension distribution and thus affects the properties of spun yarns. In conventional ring spinning, on the one hand, the spinning triangles are often asymmetric due to the frictional contacts of fibers with the bottom roller, which interferes with the twist propagation into the spinning triangle zone, and thus leads to the migration of the axis fiber at the front roller nip. On the other hand, the yarn spinning tension has an obvious angle with the vertical axis perpendicular to the nip line. Therefore, in this paper, a theoretical model of the fiber tension distributions in the general spinning triangle has been proposed by considering both the inclination angle of the spinning tension and the migration of the axis fiber at the front roller nip according to the principle of minimum potential energy. Two shape parameters were introduced to describe the skew level of the geometry of the spinning triangle in the analysis. The effects of shapes of the spinning triangle on the fiber tension distributions were investigated. The results show that the fiber tension distribution at the spinning triangle tends to more non-uniformity with increasing the asymmetry of the spinning triangle. The effects of both shape parameters on the fiber tension distributions are similar under the assumption that the spinning triangle height H is constant. In addition, a more long-narrow shape of the spinning triangle shows more uniform fiber distributions.

Numerical simulation of a three-dimensional flow field in compact spinning with a perforated drum: Effect of a guiding device

Compact spinning with a perforated drum is one of the most important kinds of pneumatic compacting. It utilizes the transverse air force in a perforated drum to condense the fiber bundle in order to effectively eliminate the spinning triangle and improve the qualities of spun yarns. Therefore, the emphasis in research on a flow field in the condensing zone is always on the difficulty of pneumatic compact spinning. In this paper, the three-dimensional flow field of compact spinning of a perforated drum with a guiding device is investigated using Fluent software. First, a three-dimensional model, using AutoCAD Software, of the condensing zone is given. Then, the numerical simulations, by using Fluent software, of the three-dimensional flow field in compact spinning of a perforated drum with three guiding devices (type A, type B, and type C) and without a guiding device are presented, respectively. It is shown that the effective range of the negative pressure in the condensing zone of the compact spinning system with a perforated drum and guiding device increases significantly as compared with that of compact spinning without a guiding device. The flow field distribution is symmetric with respect to the central line of air-suction flume. The fiber strands move toward the center under the left–right symmetric transverse air force, which achieves transverse converging effects. Meanwhile, the static pressure shows a wavy distribution due to the influence of round holes. Furthermore, it is proved that the comprehensive effect of the type C guiding device is the best. Finally, the theoretical results obtained are illustrated by spinning experiments.

Evaluation of the Correlation between the Structure and Quality of Compact Blend Yarns

Pneumatic compact spinning is the most widely used compact spinning technology at present, which is implemented by using negative airflow to condense the fibre bundle and decrease the spinning triangle. Roller-type and Lattice apron-type compact spinning are two major kinds of pneumatic compact spinning now. In this paper, blend yarn qualities spun by one kind of roller-type compact spinning: complete condensing spinning (CCS), and one kind of Lattice apron-type compact spinning: 4-line rollers compact spinning (FRCS) were studied and analysed comparatively. First, 28.1, 18.5 and 12.3 tex JC60/T40 blend yarns and 18.5, 14.8 and 11.8 tex JC35/T65 blend yarns were spun on two kinds of compact spinning systems, respectively, and the effects of the blending ratio on yarn qualities were discussed. Then another two kinds of cotton blended yarns - JC60/R40 and JC60/M40 were spun. 28.1, 18.5, 14.8 tex JC60/R40 and 18.5, 14.8, 11.8 tex JC60/M40 were spun on two kinds of compact spinning systems, respectively. Meanwhile the qualities of spun yarns were analysed by using two methods. First with a high speed camera system - OLYMPUS i-speed3 (OLYMPUS Image Co., Ltd., Japan), the condensing process of a fibre strand in the condensing zones were captured and analysed. Second the cross sec tions of the spun yarns were presented using a Y172 Hardy’s thin cross-section sampling device (Nantong Hongda Experiment Instruments Co., Ltd. , China). The corresponding Hamilton Index was then calculated, and the fibre radial distributions in the yarn cross section were analysed. The results show that the fibre condensing effects are increased with an increase in the ratio of cotton fibre on the blended yarn for both kinds of compact spin ning, especially the FRCS. Meanwhile with an increase in the ratio of polyester fibre on the blended yarn, the advantage of CCS with respect to yarn qualities increased. For both JC60/R40 and JC60/M40, cotton fibres are transferred to the outer part of the yarn body. However, the fibres in JC60/R40 yarn spun by CCS and those in JC60/M40 yarn spun by FRCS are distributed more randomly.

Research on the Compact-Siro Spun Yarn Structure

Compact-Siro spinning technology is one of the most widely used spinning methods. It is conducted on a compact ring frame by simultaneously feeding two rovings into the drafting zone at a predetermined separation. In fact, Compact-Siro spinning incorporates the features of both Compact and Siro-spinning systems. In this paper, the structure of CompactSiro spun yarn is investigated. By using a DZ3 video microscope, the horizontal structure of Compact-Siro spun yarn, Sirospun yarn, Compact yarn and Ring spun yarn were obtained. It is shown that compared with Compact single yarn, Compact-Siro spun yarn has a more compact and clear surface structure, a more uniform and smooth shape, and less hairiness. Then the cross section structure of Compact yarn and Compact-Siro spun yarn were obtained by using Hardy’s Y172 thin cross-section sampling device and the DZ3 video microscope. It is shown that compared with Sirospun yarn, the cross-section of Compact-Siro spun yarn is smoother and closer to being circular. Meanwhile in the Compact-Siro spun yarn body, the fibers of two substrands show axial symmetrical distribution approximately, which is beneficial for spun yarn qualities, especially for improving the yarn evenness and hairiness. Finally the results obtained were illustrated in spinning experiments.

Properties of Yak Wool in Comparison to Cashmere and Camel Hairs

ABSTRACT Recently, yak wool has got more and more attentions for its good quality and competitive price in textile industry. However, for its large dispersion and stiffness, there are still some difficulties in utilizing yak fibers, which also further limit the development of yak wool products. Aiming at this problem, in this article, yak wool was compared with cashmere and camel hair. Cashmere and camel hair are another two kinds of animal fibers, which have been studied for a long time and there have been mature manufacture techniques for some cashmere or camel hair products. By comparative analyzing the surface and cross-section morphologies, physical and chemical properties of these three kinds of fiber, the better ways to develop yak wool can be got. Findings show that among the three kinds of animal fibers, the scales of yak fibers arrange densest. Besides, it also has the highest strength and friction effect. As for the chemical properties, the functional groups of these fibers are similar but the acid and alkali resistances of yak wool are poorest.

Theoretical Study of the Effects of the General Division of a Ring Spinning Triangle on Fibre Tension

Su X, Gao W, Liu X, Xie C, Xu B. Theoretical Study of the Effects of the General Division of a Ring Spinning Triangle on Fibre Tension. FIBRES & TEXTILES in Eastern Europe 2016; 24, 2(116): 37-43. DOI: 10.5604/12303666.1191425 Theoretical Study of the Effects of the General Division of a Ring Spinning Triangle on Fibre Tension *Xuzhong Su1,2, **Weidong Gao1,2, Xinjin Liu1,2,3, Chunping Xie1,2, Bojun Xu1,2

Preparation and Characterisation of High Count Yak Wool Yarns Spun by Complete Compacting Spinning and Fabrics Knitted from them

Key Laboratory of Eco-Textile, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China mfgucv@163.com Abstract The attentions of the textile industry has been attracted by yak wool due to its excellent properties, environmental friendly characteristics and inexpensive prices. However, the processing of yak wool is difficult due to the larger fiber dispersion and stiffness, especially spun pure and high count yak wool yarn. Therefore, in this paper, a kind of roller-type compact spinning complete compacting spinning (CCS) was applied to spun pure high count yak wool yarns, in which a special hollow roller made of stainless steel with a strip groove structure on its surface was employed. Based on the mechanism of CCS, the processing parameters for two kinds of yak wool yarns 20.83 tex and 16.67 tex were set. Then the qualities of the yarns prepared were tested and compared with yak wool yarns spun by common ring spinning. Finally corresponding knitted fabrics were further produced and tested for wearability.

Numerical Simulation of Fibre Tension in an Asymmetric Ring Spinning Triangle Using FEM

In the paper, numerical simulations of fibre tension in one kind of asymmetric ring spinning triangle caused by horizontal offsets of the twisting point is studied by using the finite element method (FEM). A finite element model of the asymmetric ring spinning triangle is first established according to the mechanical properties of the fibre and a geometric model of the spinning triangle. Then the distribution of fibre tension and fibre torque in the asymmetric spinning triangle with and without considering fibre buckling are simulated by using ANSYS software. Effects of the offsets on the distribution of fibre tension and torque in the spinning triangle are studied in detail. The results show that with an increase in the spinning triangle offset, the asymmetric trend of fibre tension distribution in the spinning triangle is more obvious, and the value of fibre tension is also increased, whereas the fibre torque is decreased. Meanwhile with an increase in the yarn twist factor, the value of fibre tension and torque are both greatly increased. In addition, compared with the case where fibre buckling is considered, fibre tensions and torques are considerably increased in the case where fibre buckling is not considered.

Research on the Performance of a Drafting Device for the Four-Line Compact Spinning System

2Key Laboratory of Eco-Textile, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China **E-mail:gaowd3@163.com Abstract Compact spinning is one of the most important improvements of traditional ring spinning, which is implemented by adding a fibre condensing device to condense the fibre bundle and decrease the spinning triangle, thereby improving the qualities of yarn. Pneumatic compact spinning is the most widely used compact spinning method at present. Four-line compact spinning is one of the most important kinds of pneumatic compact spinning, which is implemented by using a Lattice apron to achieve fibre condensing, decrease the spinning triangle and improve the yarn qualities, especially reducing yarn hairiness. In this paper, the performances of drafting devices for Four-line compact spinning were studied. First the structure and performance of an SDDA2122PH pneumatic cradle equipped with a new kind of block top roller retaining bar were discussed and the pressure distribution of the cradle presented firstly. Then 7.3 tex T65/JC35 was spun on an EJM128K spinning frame equipped with an SDDA2122PH pneumatic cradle, the pressure distributions measured, and the spun yarn qualities were measured and analysed accordingly. Then the acting mechanism of three kinds of top pin: a common top pin without a press bar, a top pin with a front pressure bar, a top pin with a back pressure bar, with respect to yarn qualities was analysed firstly, and then JC 18.2 tex, JC60/T40 18.4 tex and T 18.4 tex yarns were spun on an EJM128K spinning frame equipped with different top pins. Then the qualities of the spun yarns were analysed according to the acting mechanism of the top pin. The results show that by using the new block top roller retaining bar, the pressure of the pneumatic cradle is larger and more stable, thereby improving the spun yarn’s comprehensive qualities. For cotton yarn, we can reduce yarn hairiness by using a top pin with a pressure bar; for chemical fibre and cotton blended yarn, yarn strength can be improved by using a top pin with a pressure bar, and for chemical fibre pure yarn, the usage of a top pin with a pressure bar is beneficial for improving yarn strength and evenness, but not for yarn hairiness and yarn thin and thick places.