Fiber Tension Distribution Research Articles

Innovative Solution for Reducing Yarns Hairiness on Ring Spinning Machines

ABSTRACT Yarn’s hairiness represents a continuous challenge for spinning technologies. To keep this aspect under control, an almost perfect combination between the construction and performance of the machines, the control of the technological processes through appropriate settings, and the experience of the producers are required. As a consequence, the researchers were preoccupied to adapt or modify the ring frame to produce yarns with a lower degree of hairiness. Spinning triangles as a very demanding area exert a crucial impact both on the distribution of fiber tension and their spatial location in the staple yarn structure. Our study encompasses yarn hairiness reduction employing a device composed of two bars. Various combinations of spindle speeds and contact angles between yarns and bars were tested to examine their effects on yarn hairiness. The study was completed with the optimization of technological parameters using a central, composite, rotating program with two independent variables (spindle speed and contact angle) to establish mathematical models and optimize technological parameters for the reduction of hairiness. The effectiveness and efficiency of this device consist of the easy execution and installation on the existing machines in spinning mills without any constructive adjustments and additional energy consumption.

Dynamics of Interaction of a Single Fiber with a Headset of a Sampling Drum

The article presents an analysis of the dynamics of interaction of a single fiber with the sampling drum of a headset during pneumomechanical spinning. The regularity is investigated and the equation of the movement of fibers on the surface of the tooth of the sampling drum headset is obtained. It was found that the dependences of the movement of fibers along the tooth at different angles of inclination, the distribution of fiber tension along the arc, and the distribution of fiber speeds in the region of the sampling arc have an increase property. As a result of the analysis of the tension and speed of the fibers, it was found that with the increase in the sampling zone, the tension force and speed of the fiber increase.

Research on yarn qualities modified by mechanical false-twisting device

In the ring-spinning process, the area between the front roller nip and twisting point is spinning triangle, and its geometry influences the fiber tension distribution in the spinning triangle directly and determines the properties of spun yarns. Therefore, in the paper, one kind of mechanical false-twisting device was introduced on the ring spinning, which can affect the twist propagation and change the spinning triangle geometry actively. First, the modification of the false-twisting device on the DTM129 ring-spinning frame was introduced. Taking the medium cotton yarn spinning as an example, corresponding ring yarn, Sirospun yarn, compact yarn were spun on the modified spinning frame under different designed twist factors, and the applicability of the false-twisting device on different spinning method was discussed. It is shown that comparing with the common yarn, the Hairiness and Strength of the modified yarns are all improved, and the effect of false-twisting device on yarn qualities is more effective for the low-twist yarn. Comparing with the ring spinning, the improvement degree of the modified compact spinning is a little smaller. Then, the long-staple cotton ring yarn, polyester and medium cotton blend ring yarn, polyester ring yarn were spun on the modified spinning frame under different designed twist factors, and the applicability of the false-twisting device on different fibers was discussed. It is shown that the influence of the false-twisting device on the long-staple cotton yarn and polyester yarn is little. That is, the false-twisting device given in the paper would be more applicable on the short fiber spinning under the low designed twist factor.

Research on the mechanism of the modified ring-spinning system using a dynamic twist-resistant device and its yarn quality

The spinning triangle is a critical area in the ring-spinning process; the geometry of the spinning triangle influences the distribution of the fiber tension, and affects the qualities of the spun yarn. In this paper, a kind of dynamic twist-resistant device that can affect the geometry of the spinning triangle is employed for improving the conventional ring-spinning system. The yarn twists between the front roller nip and dynamic twist-resistant device were captured in the spinning process using a high-speed camera. Comparing yarn twists of the two types of yarn, the modified yarns have a lower twist angle, indicating that the device can produce resistant torque. Particle Flow Code software was used to simulate the acts of the device on the yarn, and the results verified the existence of resistant torque. The resistant torque on the yarn affects the geometry of the spinning triangle and the distribution of fiber tension. In addition, 19.4 and 14.5 tex cotton yarns with three different twists, 700, 800 and 900 tpm, were produced by the modified and conventional ring spinning. The comparative study revealed that the modified yarns have a better performance in terms of yarn strength and hairiness, and show no significant difference in terms of the yarn evenness when compared with the conventional yarns at the same twist level. The mechanism of the effect of the dynamic twist-resistant device on yarn qualities is discussed by analyzing the distribution of fiber tension.

Study on Spinning triangles in the common ring spinning and Super draft ring spinning systems

In the paper, one kind of super draft ring spinning frame with four drafting rollers and corresponding three drafting zones were introduced. The yarn qualities spun by the super draft ring spinning frame were analyzed by studying the shape of spinning triangles. Using the high speed camera system OLYMPUS i-speed3 and one kind of transparent front top roller, the spinning triangles were captured, and the geometry size of spinning triangle were measured. Then, according to the theoretical model of fiber tension in the spinning triangle, fiber tension distributions in the spinning triangles were presented by using Matlab software. Using the combed roving of 350 tex as raw material, three kinds of cotton yarns, 27.8 tex (21S), 18.2 tex (32S) and 14.6 tex (40S), were spun in the common ring spinning frame with three different suitable spindle speeds, travelers and twist factors. Using the combed roving of 350 tex and 500 tex as raw material, 14.6 tex cotton yarns were spun in the super draft ring spinning frame with three different drafting ratios at back zone. It is shown that with the increasing of spindle speed, a more asymmetric shape of spinning triangle would be produced, and lead to worsen yarn evenness. With the decreasing of traveler weight, the height and horizontal deviation of the spinning triangle is decreased, and may lead to better yarn evenness and less long hairiness. By taking suitable large yarn twist factors, the comprehensive qualities can be improved. Comparing with the common ring spinning, the spinning triangle is larger in the super draft ring spinning. That is, in the super draft ring spinning, the fibers in the strand in the front roller nip are more dispersed, and not benefit for yarn qualities. Therefore, the compact device was introduced into the super draft ring spinning, and the cotton pure yarns and blend yarns were spun, and the yarn qualities were measured and analyzed.

Research on mechanical properties of fibers at asymmetric ring spinning triangle using Finite Element Method

In the ring spinning process of staple yarn, spinning triangle is a critical zone, whose geometry influences the mechanical properties of fiber in the spinning triangle directly. In the practical spinning, especially in some modified ring spinning systems, the spinning triangle is often asymmetric, in which the horizontal deviation of the twisting point is existed and lead to an obvious angle between the yarn spinning tension and the vertical axis perpendicular to the nip line. Therefore, in this paper, the fiber tension distributions in this kind of asymmetric spinning triangle were studied using the finite element method. In the direct finite element model, the initial strain of fibers in the two sides of spinning triangle is asymmetric, and corresponding accidental fiber tensions would be produced, which makes the fiber move to the middle of the spinning triangle and lead to inaccurate results. Therefore, in the paper, one new finite element model of the asymmetric spinning triangle with left (right) horizontal deviation was presented for calculating the fiber tension. In the model, an asymmetric spinning triangle with the same right (left) horizontal deviation was used to combine with the original asymmetric spinning triangle, and one axisymmetric quadrangle was built, and the symmetry axis is the central fiber. Then, the fiber tension and torque distributions in the spinning triangles of Ne40 (14.6 tex) and Ne60 (9.7 tex) cotton spun yarn were numerical simulated with different horizontal deviations and twist factors. Furthermore, the accuracy of the proposed finite element model in calculating the fiber tensions was validated by comparing it with the theoretical model built by the energy approach.

Theoretical Study of Effect of Ring Spinning Triangle Division on Fiber Tension Distribution

The spinning triangle is a critical region in the spinning process of staple yarn. Its geometry influences the distribution of fiber tension at spinning triangle directly and affects the qualities of spun yarns. Taking appropriate measures to change the ring spinning triangle geometry and improve the qualities of yarn has attracted more and more interest recently. Spinning triangle division is one of the most effective measures, such as solospun technology. Therefore, in this paper, the effect of ring spinning triangle division on fiber tension distribution was studied theoretically. The general case that the spinning triangle is divided into two parts, primary triangle and final triangle, was investigated. Firstly, theoretical models of the fiber tension distributions in the final and primary spinning triangles are given respectively using the principle of minimum potential energy. Secondly, the fiber tension distributions in the spinning triangle with different shape parameters are numerically simulated. Finally, the possible effects of ring spinning triangle division on yarn qualities are analyzed according to the numerical simulations and previous results. In addition, the properties of spun yarns produced by the modified ring spinning system were evaluated and analyzed.

Theoretical study of fiber tension distributions at the twist point

Purpose – Spinning triangle is a critical region in the spinning process of staple yarn, which geometry influences the distribution of fiber tension and determines the qualities of yarn directly. Therefore, the purpose of this paper is to investigate the fiber tension distribution at the twist point. Design/methodology/approach – First, one theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle. Then, one calculation method of fiber tension at the twist point is given by two steps. First, the initial tension of each fiber at the front nip line caused by the yarn load should be calculated according to the models obtained based on the principle of minimum potential energy. Second, the fiber tensions at the twist point can be calculated using the obtained model in this paper. Finally, as an application of the proposed method, spinning triangles of a modified ring spinning system with a pair of offset device which can change the horizontal offset of the twist point to the symmetric axis of nip line of the spinning triangle continuously are studied. The fiber tension distributions are simulated numerically. Findings – It is shown that the fiber tension distributions at the twist point can be determined by fiber feeding into and out the spinning triangle speed, the initial tension of each fiber at the front nip line, fiber tensile Young’s modulus and cross-sectional area, the number of fibers at spinning triangle and the individual fiber angle with the center fiber. The spinning experiment shows that taking appropriate right or left offset of the spinning triangle can help to improve the spun yarn qualities. Originality/value – In this paper, the fiber tension distribution at the twist point is investigated. One theoretical model of fiber tension distributions at the twist point is given according to the motion law of fibers in the spinning triangle first. Then, one calculation method of fiber tension at the twist point has been given under the assumption that the initial tension of each fiber at the front nip line is caused by the yarn load.

Research on fiber tension at asymmetric spinning triangle using the finite-element method

Spinning triangle is a critical zone in the ring spinning process of staple yarn, whose geometry influences the fiber tension distribution in the spinning triangle directly and determines the spun yarn qualities. In ring spinning, the spinning triangle is often asymmetric due to the inclination angle of the spinning tension or the migration of the axis fiber at the front roller nip. Therefore, in this paper, the fiber tension distributions in the asymmetric spinning triangle due to the migration of the axis fiber at the front roller nip were studied using the finite element method (FEM). In the direct finite-element model, the initial strain of the axis fiber is set as zero, and the accidental fiber tensions would be produced due to the asymmetric distributions of the initial strain on fibers in the two sides of the spinning triangle. Then, an effective finite-element model of the asymmetric spinning triangle with right (left) axis fiber migration for calculating the fiber tension is built by composing an asymmetric spinning triangle with a corresponding left (right) axis fiber migration and a symmetric spinning triangle is composed. Then, the fiber tension distributions in the spinning triangles in the Ne40 (14.6 tex) and Ne60 (9.7 tex) cotton spun yarn were numerically simulated with different axis fiber migrations and twist factors. Furthermore, the accuracy of the proposed finite-element model in calculating the fiber tension distribution in the asymmetric spinning triangle was validated by comparing it with the theoretical model built by the energy approach. It is shown that the numerical values of fiber tension distribution between the FEM results and the results with the energy method are in good agreement. Meanwhile, with the increase in the migrations of the axis fiber or the yarn twist, fiber tension in the spinning triangle is increased.

Theoretical study on a spinning triangle with fiber superposition

In some new modified ring spinning systems, fiber superposition in the front nip line often exists, that is, each fiber in the spinning triangle is not distributed evenly, but some fibers are divided into substrands or bundles. Therefore, in this paper, a theoretical model of fiber tension distribution in the spinning triangle is proposed by considering the fiber superposition at the spinning triangle based on the principle of minimum potential energy. The symmetric and asymmetric spinning triangle due to the inclination angle of the spinning tension and the migration of the axis fiber at the front roller nip were all considered, and theoretical models of fiber tension distributions in the corresponding spinning triangles were given. The relationships between the fiber tension and the spinning triangle shapes were studied. Finally, as an application of the proposed method, ring spinning triangles the 14.6 tex (40S) cotton yarn spinning were taken as an example for the simulation. The numerical simulations of fiber tension distributions in the spinning triangle were presented and analyzed comparatively. In particular, the effect of both fiber superposition and the distance between two adjacent substrands in the front nip on fiber tension distributions were discussed. The results show that when there is fiber superposition in the front nip, comparing with the case that each fiber is distributed evenly, the tensile force of the two boundary fibers is decreased slightly, and the compressive force of the central fibers is also increased slightly, which leads to similar magnitudes.

Numerical analysis of fibers tensions in the Siro-spinning triangle using finite element method

Siro-spinning is a new kind of modified ring spinning method and achieved by feeding two rovings simultaneously, which have three spinning triangles including two primary spinning triangles and one final spinning triangle. In this paper, by using finite element method (FEM), the quantitative relationships between the fiber tension in the Siro-spinning triangle and some chosen important spinning parameters are investigated. The constituent fibers in the Siro-spinning triangle are considered as three-dimensional elastic beam elements with tensile, compressive, torsion, and bending capabilities. Then, the finite element model of Siro-spinning triangle is constructed under the assumption that the ends of all fibers gripped in the front roller nip distribute evenly, and the initial strain of the central fiber in each primary triangle is set as zero. Finally, the effects of some more important parameters of the Siro-spinning triangle, including the spinning yarn count, spinning tension, yarn twist, the distance between two feeding bell mouths on fiber tension distributions, are numerically examined and their quantitative relationships are discussed in detail. The accuracy of the proposed FEM model in calculating the fiber tension distribution of the Siro-spinning triangle has been validated by comparing it with our earlier theoretical models. Furthermore, the spinning experiments with different progress parameters were made, and the properties of spun yarns were evaluated and analyzed.

Research on mechanical properties of the Siro-spinning triangle using the Finite Element Method

Siro-spinning (two-strand yarn spinning) is a new kind of modified ring spinning method, which is achieved by feeding two rovings into the apron zone at a predetermined separation simultaneously. There are three spinning triangles, including two primary spinning triangles and one final spinning triangle, in Siro-spinning. Therefore, in this paper, the quantitative relationships between the mechanical performance of a Siro-spinning triangle and the spinning parameters are investigated by using the Finite Element Method. The finite element model of the Siro-spinning triangle is constructed under the assumption in which the constituent fibers are considered as three-dimensional elastic beam elements with tensile, compressive, torsion, and bending capabilities. Three different cases where the ends of all fibers, the initial strain of all fibers, and the angle between any two adjacent fibers gripped in the front roller nip distribute evenly are discussed. Meanwhile, in each case, three different cases where the initial strains of the shortest boundary fiber, the central fiber, and the virtual fiber on the direction of yarn spinning tension are set as zero are discussed respectively. Then, taking the spinning triangle in Ne40 (14.6 tex) cotton Sirospun yarn as an example, the fiber tension distribution and fiber torsion distribution in the corresponding Siro-spinning triangle with and without fiber buckling are numerical simulated. It is shown that the fiber tension distributions are influenced by the setting of the fiber initial strain, while the magnitudes of fiber tension are not affected. Finally, Ne40 cotton ring yarns were spun on an EJM128K ring spinning machine, and the properties of spun yarns were evaluated and analyzed according to the simulation results.

Theoretical study of spinning triangle with fiber concentric circular cones arrangement at front nip line

Spinning triangle is a critical region in the spinning process of staple yarn, which geometry influences the mechanical performances of fibers in the spinning triangle and determines the physical performance of spun yarns directly. Taking appropriate measures to reduce the spinning triangle and improve the qualities of yarn has attracted great interesting recently. In these modified ring spinning systems, the fibers in the spinning triangle are not arranged in the same plane, but arranged in concentric circular cones at front nip line, such as compact spinning, in which a fiber-converging device is installed on ring spinning frame, and the fiber bundle can be condensed before twisting in order to reduce the spinning triangle. Therefore, in this paper, a new theoretical model of fiber tension distribution in the spinning triangle with fiber concentric circular cones arrangement at front nip line is proposed based on the principle of minimum potential energy firstly. Then, corresponding residual torque within a yarn caused by the fiber tension is given. Finally, as an application of the proposed method, taking the spinning triangle in Ne40 cotton yarn 3-line rollers compact spinning as an example, the fiber tension distributions in the spinning triangle both with and without fiber buckling and corresponding residual torque within a yarn are numerically simulated, and the results are compared with those from earlier model. Furthermore, the properties of spun yarns produced by compact spinning system and ring spinning system are evaluated and analyzed.

Theoretical study of fiber tension distribution at Solospun spinning triangles

Spinning triangle is a critical region in the spinning process of staple yarn. Its geometry influences the distribution of fiber tension in the spinning triangle and affects the properties of spun yarns. Taking appropriate measures to influence the spinning triangle geometry and improve the quality of yarn has attracted great interesting recently. Solospun technology is one of the most important representatives, which is implemented by dividing ring spinning triangle into several small primary triangles and one final triangle using a Solospun roller. Therefore, theoretical study of fiber tension distributions at Solospun spinning triangles is presented in this paper. First, a theoretical model of the fiber tension distributions in Solospun spinning triangles is given by using the principle of minimum potential energy. Second, the relationships between fiber distributions and spinning triangle parameters are analyzed theoretically. Especially, the effects of horizontal offset of the twisting point to triangle symmetric axis of nip line d on fiber tension distributions are discussed and numerical simulations are given. Finally, the properties of spun yarns are evaluated and analyzed by using the simulation results.

Review of distribution of fiber tension at the spinning triangle

In the ring spinning process, the spinning triangle plays an important role in the quality and efficiency of yarn spinning. The distribution of fiber tension at the spinning triangle is important. In this study, models such as energy methods, energy methods using false twist, and finite element method are applied. The model parameters on the distribution of fiber tension in the symmetric and asymmetric spinning triangle with a uniform distribution of single fiber, uniform distribution of fiber types, and distribution buckling fibers in the spinning triangle are analyzed. The results show that there is an increase in the distribution of fiber tension in symmetric spinning triangle. Fibers, depending on their position in the spinning triangle, have different tensions. In single fibers in the twist point, the tension of the fiber bundle is maximum, the fiber tension is less, and the compression force of the fiber bundle is greater. The spinning triangle shape is effective on the distribution of fiber tension.

Research on spun yarn qualities in a modified ring-spinning system using airflow-twisting device

In this paper, a kind of airflow-twisting devices which can produce the twist by the high vortex airflow is employed for improving the twist propagation process of ring-spinning system. Firstly, three different kinds of yarns Ne20, Ne40, and Ne60 are spun in this modified ring-spinning system with five different airflow pressures and two different swirling directions, including anticlockwise and clockwise, and the qualities of spun yarns, including hairiness, strength, evenness, and number of snarling characterizing the yarn residual torque, are measured. Secondly, the images of spinning triangles are captured by using a high speed camera system OLYMPUS i-speed3, and the mechanism of the effects of vortex airflow on yarn qualities is discussed by analyzing the fiber tension distributions in the spinning triangle. It is shown that for the ‘Z’ twist spun yarn, the spinning triangle decreases with the increasing of clockwise airflow pressures, whereas the triangle becomes more and more symmetrical with the increasing of anticlockwise airflow pressures. Meanwhile, the comprehensive qualities of spun yarn are improved with the increasing of both directions of airflow pressures to a certain extent. However, the hairiness and strength of spun yarn will be mainly improved with clockwise airflow, whereas yarn residual torque mainly reduced with anticlockwise airflow.

Theoretical study of spinning triangle with raised part

Spinning triangle is a critical region in the spinning process of staple yarn, the geometric and mechanical performances of which plays an important role in determining the physical performance of spun yarns. Taking appropriate measures to influence the spinning triangle geometry and improve the qualities of yarn has greatly attracted interest of many researchers recently. In these modified ring spinning systems, the raised parts at spinning triangle are often existed, i.e. the fibers in the spinning triangle are not on the same plane, but a part of fibers is squeezed into the middle part of spinning triangle by the heavy twist. Therefore, in this paper, a new theoretical model of fiber tension distribution in the spinning triangle is proposed by considering the raised parts at spinning triangle based on the principle of minimum potential energy. The relationships between the fiber tension and the spinning triangle shapes are presented. Then, a theoretical model of the residual torque within a yarn due to the fiber tension was given correspondingly. Finally, as an application of the proposed method, Ne32 cotton yarns were taken as an example for the simulation. The fiber tension distributions in the spinning triangle and corresponding residual torque within a yarn were numerically simulated and the results were compared with those by earlier models, in which the fibers in the spinning triangle were assumed to be located on the same plane.

Research on Sirospun yarn torque using airflow false twisting device

Yarn torque is one of the most important indexes of yarn quality, which is determined on the mechanical state of the constituent fibers and their configuration in the yarn. The fiber tension within a yarn was proposed to be the most influential factor governing the magnitude of yarn torque by Bennett and Postle. Therefore, the research on Sirospun yarn torque is investigated by analyzing the fiber tension at spinning triangle in this paper. Firstly, theoretical models of the fiber tension distributions at primary and final spinning triangles are presented, and corresponding residual torque within a yarn due to the fiber tension is given. The relationships between the yarn torque and the spinning triangle parameters are analyzed theoretically. Secondly, as an application of the proposed method, a modified Sirospun spinning system with an airflow false twisting device which can change spinning triangle parameters are investigated, and the properties of spun yarns produced by the modified system are evaluated and analyzed. It is shown that with the increasing airflow pressures, the Sirospun yarn shows a more and more uniform distribution of tensile and compressive stress within a yarn, and thus the yarn torque decreases correspondingly.

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.

Reducing Yarn Hairiness in a Modified Ring Spinning Yarn Path by Various Offsets

Spinning triangle is a critical region in the spinning process of yarn. Its geometry influences the distribution of fiber tension in the spinning triangle and the properties of spun yarns, such as the yarn breakage and hairiness. In this paper, the relationships between the spinning angle and yarn properties especially the yarn hairiness were investigated under various horizontal offsets. The properties of spun yarns produced by the modified system were evaluated and analyzed. Both left diagonal and right diagonal yarn arrangements were examined. The results indicate that the right diagonal yarn path leads to reduce yarn hairiness but the left diagonal yarn path leads to increase yarn hairiness; the breaking force of yarn changes little; yarn evenness deteriorates slightly with the changes of offset.