Journal articles on the topic 'Twist insertion process][Yarn spinning'

Vortex spinning, which adopts high speed airflow to insert twist into the yarn, is one of the most promising technological innovations in the textile industry. In vortex spinning, the dynamic behavior of the fiber inside the nozzle, which involves fiber-airflow interaction and fiber-wall contact, plays an important role in the twist insertion process. This paper investigates the airflow characteristics and the fiber dynamic behavior inside the vortex spinning nozzle via a two-dimensional numerical model with the fiber-airflow interaction and fiber-wall contact included. The fiber is assumed to be isotropic, elastic material. The airflow inside the nozzle is assumed to be turbulent, viscous and incompressible. The numerical results show that two vortices with momentarily changed sizes are created upstream of the jet orifice outlets. The imbalance of the pressure around the fiber causes the fiber to move and deform. The trailing end of the fiber rotates with wave shape within the nozzle chamber for several periods to insert twist into the yarn. Based on the model, the effects of three nozzle structure parameters – the jet orifice angle, jet orifice diameter, distance between the nozzle inlet and the hollow spindle, on the dynamic behavior of the fiber, and in turn, the yarn structure and tensile property are investigated. The results show that the appropriate jet orifice angle for obtaining the best yarn tenacity is 70°. The optimal jet orifice diameter is 0.4 mm. The spun yarn has the highest tenacity when the distance between the nozzle inlet and the hollow spindle is 14 mm.

Based on the physical properties of Ni-Fe fiber, the orthogonal design was adopted to determine the parameters including roving twist, back zone drafting multiple and yarn twist, and the strength and wear resistance of the produced five kinds of yarns were tested and analyzed. The results show that to solve the problem of mixing uniformity of Ni-Fe Fibers, the suitable drawing numbers can be adopted. And the appropriate roving twist, spinning back zone drafting multiple and yarn twist are key factor of resultant yarn.

Twisting is an important process to form a continuous yarn from short fibers and to determine the structure and properties of the resultant yarn. This article reports on the effect of variation of false twist on process stability and resultant yarn quality in a modified ring spinning frame. Based on twist kinematics, three practical cases that cause twist variations in the spinning process are investigated, namely step function, rectangular function and periodic function changes in false twist. The simulation results are validated by experiments and a good agreement has been demonstrated. The resultant properties of yarn within 30% periodic change in false twist demonstrated insignificance compared with yarn without variation. With the developed model, essential system parameters are numerically examined and their quantitative relationships are studied. The practical implications are discussed.

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.

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.

A mathematical model is established for self-twist spinning process by applying laws of fluid mechanics (i.e. mass conservation and momentum conservation). The motion curve of the convergent point was determined and the convergence point was decided by densities and velocities of two fed-in strands and the resultant self-twist yarn, independent of their mechanical properties. The experimental verification proves that the motion trajectory of the convergence point reaches a better agreement with the theoretical trajectory. The results provide general way to study the self-twist yarn spinning process and optimize the process parameters.

Limited studies exist related to the siro-spun spinning of flax ( Linum usitatissimum L.) and cotton (Gossypium hirsutum) blends. The purpose of this study was to determine the influence of various siro-spun processing parameters, including twist factor, space between two rovings and specification of traveler, on yarn qualities, such as yarn hairiness, tenacity and evenness. Results show that both specification of traveler and space between two rovings significantly influenced yarn hairiness and evenness, and heavier traveler and greater space led to decreased hairiness, but bad evenness. Twist factor influenced yarn evenness highly significantly, and smaller twist factor led to worse yarn evenness. Results also indicate the optimum levels of siro-spun process parameters as follows: twist factor αm = 150, space between two rovings 8 mm, traveler Fo 5/0. In relation to the general ring-spinning yarn, the siro-spun spinning yarns had decreased hairiness, little increased tenacity and similar evenness.

Abstract Rotor speed and twist per metres (tpm) are two key parameters in open-end rotor spinning of cotton yarns. High spinning productivity can be obtained by keeping the rotor speed high and twist level as low as possible. However, too high rotor speed may result in yarn imperfections and too low twist level may result in lower tenacity yarns. This study aimed at optimising the multiple yarn characteristics in open-end rotor spinning using the Taguchi method and the grey relational analysis. Cotton yarn samples of 30 tex were produced on rotor spinning machine with different twist levels (i.e. 500, 550, 600 and 700 tpm) at different rotor speeds (i.e. 70,000, 80,000, 90,000 and 100,000 rpm) according to the Taguchi design of experiment. Optimal spinning process parameters were determined using the grey relational grade as the performance index. It was concluded that for the cotton fibres and yarn count used in this study, optimum properties of the yarns could be obtained at 90,000 rpm rotor speed and 700 tpm.

For the prediction of yarn quality, this paper presents method to predict the quality of the spinning by a support vector machine. The input parameters to support vector machines including density of coarse yarn, roving twist factor, yarn linear density, yarn twist factor , the output variable is the CV values of spinning, breaking strength, establishment prediction model of CV values, breaking strength SVM. The results showed that: 11 groups of training samples randomly selected from 13 groups samples, two groups as predict sample, forecast errors are below 5% with high accuracy. This research provides a new approach for the spinning process design and quality control.

In the ring spinning system, a dynamic twist-resistant device has been applied to improve yarn quality. In this paper, a mechanical model quantifies the relationship between twist blockage, yarn tension, and the parameters of the device and yarn when yarn passes through the dynamic twist-resistant device. During the modeling process, the force applied by the twist-resistant device was considered, and the twisting torque was precisely calculated by yarn tension rather than calculated by the assumption that yarn-twisting torque is linearly related to the yarn twist. Finally, twist blockage and yarn tension are given as a function of the normal force applied by the device, the radii of cylinders in the device, warp angle, deviation angle and radius of the yarn. The simulation results are presented and analyzed.

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.

Twisting is an important process used to form a continuous yarn from short staple fibers and to determine the structure and properties of the resultant yarn. This paper systematically examines the yarn twisting process in a modified ring spinning process based on a theoretical model proposed recently. To reduce the number of experiments, response surface methodology (RSM) involving a central composite design (CCD) in three factors—twist multiplier, speed ratio and wrap angle—was successfully employed for the study and analysis. The significant terms of the models were studied, and it was discovered that the speed ratio and wrap angle are statistically significant for the responses of twist efficiency, propagation coefficients of twist trapping, and congestion. More importantly, linear relationships were found among the three responses.

To clarify the formation mechanism of a source of yarn and to discuss the effects of supplied air pressure and exhaust air pressure on the fiber suction force and twist torque at the starting time of the spinning process in an air-jet spinning machine, we simulated, numerically, the three-dimensional airflow pattern without fibers in the spinning zone. Results obtained are as follows: High-speed air jetted through the starting nozzles into the yarn duct in the circumferential direction causes a swirl flow in the yarn duct and a negative pressure region near the center axis of the yarn duct. Hence, air and fibers at the fiber inlet are sucked through the processing duct into the yarn duct. A fiber bundle sucked into the yarn duct rotates, owing to the action of the swirl airflow, and twists the fiber bundle in the processing duct, hence generating a source of yarn. The fiber suction force takes a distribution with a peak against the supplied air pressure and is independent of the exhaust air pressure. The fiber twist torque increases monotonously with supplied air pressure.

Spinning kenaf fibers into yarns is challenging due to the stiffness and lack of cohesiveness of the fibers. Alkali treatment is known to remove hemicellulose, wax, and breaks down lignin, reducing stiffness of kenaf fiber and improving its spinnability. Kenaf fibers were treated at percentages of 4% and 6% and blended with cotton fibers at blend ratios of 40:60 and 50:50 prior to a ring spinning process to produce a double ply yarn of 70 tex. Yarn were twisted at three sets of twist. The responses were measured in terms of carding waste percentages and yarn strength. The results showed that the optimized yarn structural parameter is kenaf fiber treated at 6% and with a kenaf/cotton 40/60 blending ratio based on its tenacity and minimum carding waste. ANOVA shows that there is a good interaction effect between NaOH and kenaf/cotton ratio, and NaOH concentration and twist.

To improve the yarn quality, the pressure bar was installed in the break drafting zone of the INA-V spinning frame. The process parameters were optimized in the break drafting zone with pressure bar of the INA-V spinning frame, the drafting principle in the break drafting zone with pressure bar of INA-V spinning frame was analyzed, and the sliver configuration was observed in the break drafting zone with pressure bar. The result revealed that installed the pressure bar in break drafting zone after, when the roving twist factor was small, CV%, thinness, thickness and neps of the yarn spun decrease as the break drafting ratio increase; when the twist factor of roving was larger, the break draft ratio as 1.3 time was optimum drafting conditions. The yarn quality was improved as roving twist increased.

The coefficients of variation-length curves for yarn twist and linear density have been determined for polyester/cotton yarns spun by ring, rotor, and friction processes as a function of blend proportion, yarn twist, and yarn linear density. The influence of each of these parameters on twist and linear density irregularity is described according to the spinning process. The coefficients of variation length curves can be mathematically represented with sufficient accuracy by a polynomial expression including first-and second-order terms.

Siro yarns are spun from two separate roving of same type of materials. Similarly in textile arts,folding is a process used to create a strong and balance yarn by putting together two separate yarns. Hence,this research study was carried to analyse the quality of Siro-spun and two fold yarns under the influenceof twist factor with special reference to their tensile properties. The results disclosed better tensile propertiesof yarn made from Siro spinning technique as compared to two plied yarn. This indicates the supremacyof Siro-spun yarn over two fold yarn. These findings enhance the fact that Siro spinning technique producesbetter quality yarn as compared to conventional ring spinning technique.

Purpose The use and importance of mélange yarn in apparel sector is increasing day by day. With the gradual increase in market share, achieving the desired quality level of mélange yarn remains a challenge for yarn manufacturing industry. The purpose of this paper is to investigate the effect of raw material (dyed fiber percentage in the mixing), important spinning process variable (yarn twist multiplier) and productivity (spindle rpm of ring frame) on properties of cotton mélange spun yarn. Design/methodology/approach Box and Behnken Design of experiment has been used to investigate the important yarn quality parameters like evenness, imperfection, hairiness, breaking strength and breaking elongation of blow room blended cotton mélange yarn. The quadratic regression model is used to derive the statistical inferences about sensitivity of the yarn quality parameters to the different process variables. The response surfaces are constructed for depicting the geometric representation of yarn quality parameters plotted as a function of process variables. Findings The study shows that shade depth and spindle speed have significant effects on the mélange yarn unevenness and imperfections. Mélange yarn strength and hairiness are significantly affected by shade depth and yarn twist multiplier (TM). Yarn elongation at break is only influenced by the spindle speed. A darker shade is responsible for higher yarn unevenness, imperfection, hairiness and lower yarn strength. A higher spindle speed is also liable for deterioration of yarn quality. Practical implications Many spinning industries are planning to convert their existing spindles from normal gray yarn production to mélange yarn manufacturing. The outcome of this study will lead to achieve better mélange yarn quality and productivity by the industry. Originality/value Research on mélange yarn is itself scant. This study is exclusively conducted to analyze the individual and interactive effect of various process parameters on the mélange yarn quality.

This study reports a numerical analysis on embeddable and locatable spinning systems. The finite element method is used to quantify the relationship between the tension and twist of staple strands and the spinning parameters. The model was constructed using the three-dimensional beam element, which is capable of simulating the stretching, bending and torsion behavior of the filament and the staple strand. It was found that the staple strand shares far less load (around 13.8%) than the filament during the spinning process. The twist is mainly distributed on the composite yarns and less on other zones. The pretension of the filament, the filament–strand distance ratio, the twist of the composite yarn and the material fed-in velocity were investigated for their influence on the tension and twist of the staple strand. Numerical predictions showed that higher filament tension and filament–strand ratio lead to less load and more twist on the staple strand. This is beneficial in producing stronger and smoother yarns and avoiding end breakages. It was also determined that strand tension and twist increase with an increase in composite yarn twist and a decrease in material fed-in velocity.

Reducing yarn hairiness on a ring spinning machine generally involves an investment and ongoing process cost. Although conceptually successful, the cost factor associated with existing technologies has led to exploration for new ways of reducing hairiness. Offset spinning is an outcome of one such novel initiative in which the spinning triangle geometry is altered by diagonally offsetting the yarn path during spinning. This technique has been reported to reduce hairiness but a consensus on a specific direction of offset (left or right) remains pending as its underlying mechanism is still not completely understood. In this study, we developed an experimental setup to image a spinning triangle geometry in detail and observed the effect of offsetting its shape on fiber path. It was found that the direction of offset (left or right) in combination with a specific twist direction (S or Z) can result in a complete change of yarn twist configuration (Archimedean or Fermat's spiral), which ultimately controls hair generation tendency during spinning. On the basis of agreement between imaging observations and hairiness parameter results obtained from yarns spun with different offset conditions, a mechanism of hairiness reduction and preferred direction of offset is proposed.

Purpose Dref-3 friction spun core yarns produced using staple fibre yarn as the core, e.g. Jute core yarn wrapped with cotton fibre, have poorer mechanical properties compared to the core yarn itself. The purpose of this study was to understand the structure of such yarns, that will lead to the optimization of fibre, machine and process variables for production of better quality yarn from the Dref-3/3000 machines. Design/methodology/approach The Dref spinning trials were conducted following a full factorial design with six variables, all with two operative levels. The Dref-3 friction spun yarn, in which the core is a plied, twisted ring yarn composed of cotton singles and the sheath, formed from the same cotton fibres making the singles, has been examined. The structures have also been studied by using the tracer fibre technique. Findings It was observed that rather than depending on the plied core yarn, the tensile properties of the Dref-3 yarn are significantly determined by the parameters those affect the constituent single yarn tensile properties, i.e. the amount of twist and its twist direction, yarn linear density and the sheath fibre proportion used during the Dref spinning in making the final yarn. Further, when the twist direction of single yarn, double yarn and the Dref spinning false twisting are in the same direction, the produced core-sheath yarn exhibits better tensile properties. Practical implications The understanding of the yarn structure will lead to optimized production of all staple fibre core Dref spun yarns. Social implications The research work may lead to utilization of coarse and harsh untapped natural fibres to the production of value-added textile products. Originality/value Though an earlier research has reported the effects of sheath fibre fineness and length on the tensile and bending properties of Dref-3 friction yarn, the present study is the first documented attempt using the tracer fibre technique to understand Dref-3 yarn structure with plied staple fibrous core.

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.

Aiming at achieving online monitoring of the yarn formation process of vortex spinning, this paper presents a direct observation method that adopts a charge-coupled device camera fitted with an industrial endoscope that can reach into the nozzle chamber through a small hole drilled on the nozzle wall. Local pressure distortion in the vortex chamber due to the mounting of the observation apparatus was found experimentally. However, the yarn quality was not significantly affected, indicating that the proposed method has the potential to find industrial applications. Based on this method, the formation process of core-spun yarn containing a copper wire manufactured on a modified vortex spinning system is successfully observed. The results show that the core wire is covered by the main strand (core fibers), while the main strand is false-twisted during the yarn formation process. The level of false twist in the main strand fluctuates with time. The level of false twist in the main strand is higher in the upstream region, while it gradually decreases toward the downstream. Mostly, the trailing ends of some fibers are separated from the main strand and expand over the spindle tip to wrap around both the core fibers and core wire to form wrapper fibers in the yarn, while the leading ends of a smaller number of fibers are separated to form wrapper-wild fibers in the yarn. The proposed method can be extended to the study of fiber movement in confined spaces in other textile manufacturing processes.

Yarn’s surface to metal friction is an important consideration in the subsequent process of knitting and weaving as it influences mainly the ends down rate, fly generation, process efficiency, wear and tear of machine parts, and production rate of the process. These frictional properties are measured in terms of the coefficient of friction of yarn. The effect of cotton type, yarn twist, yarn linear density, process type, and finishing treatment was studied on the surface to the metal friction coefficient of cotton spun yarn using Taguchi experimental design. The experiments were conducted with Pakistani and Indian cotton using combed and carded ring spinning processes. Using Taguchi design of experiment, a total of 36 samples of cotton ring-spun yarns were produced. The coefficient of friction between the yarn’s surface and metal’s surface is measured in compliance with ASTM D3108. The outcome of the Taguchi model to predict the coefficient of friction of yarns with a predefined combination of constituting parameters was further confirmed with nine yarn samples. The frictional characteristics of yarns are found to be influenced by all factors. In addition to the application of wax, the longer fiber length, lower trash count, lower short fiber index, and the optimum level of twist are found advantageous to reduce the yarn coefficient of friction.

Through wetting pretreatment of the bamboo silver fiber, taking light ration, slow speed, large twist, and other feasible process configuration and technology measures, making the yarn quality reach a better level; optimizing spinning process, sizing formula, sizing process and weaving process to improve the weaving efficiency and improve the fabric style. It successfully developed the cotton-blended antibacterial functional fabrics of the bamboo pulp silver fiber.

In this study, the response surface methodology is used to predict the mechanical properties of yarn, their unevenness and hairiness by using the high-volume instrument (HVI) properties of raw cotton and the parameters of the spinning process. Therefore, five different blends of cotton are processed and spun into ring yarns (Nm13, Nm19, Nm 21, Nm31 and Nm37). Each count is spun at five twist levels (450, 500, 650, 750 and 850 trs/m). The models that are developed by using response surface regression with many iterations on a Minitab16 statistical software predict very well the different yarn properties since the R2 values obtained are very important. In addition, these models show that metric number and twist have the highest effect on the four studied parameters

The modeling and simulation of the staple fiber spinning process is still a challenging concept in yarn technology due to the complexity of the process and uncontrollable parameters. This work presents a staple fiber yarn formation model based on the ideal assumptions about the configuration of the fibers and the cross-section of the sliver. The model presented utilizes a novel designed computer algorithm that randomly arranges staple fibers of defined length to simulate the typical arrangement of the fibers in a roving in the form of a fiber strand, which is then simulated in ABAQUS software to undergo the yarn formation stages, and the details are analyzed. The simulation results show the entire process of the twisting of the sliver and calculation of the configurational changes of each fiber in the strands is extracted. According to the model, the stages of the twisting of the sliver into the yarn are captured and presented, and the process of how the sliver converts to the yarn is analyzed in detail. In the real twisting experiment of the sliver, the propagation of the twist and the configurational changes of the fibers in the simulation experiment were verified. The experimental and numerical data are in good agreement and the model presents a precise mechanism for yarn formation. The work can be utilized to classify and understand fiber behavior during yarn processing, which can result in optimizing the staple fiber spinning technology.

In order to obtain the optimal collocation of two important technological parameters in the spinning process, the multi-response surface method was used to optimise the experimental results. Through the orthogonal design of the two factors and four levels of factor encoding, 16 groups of orthogonal experiments were designed; the experimental results were fit using the curve fitting toolbox of Matlab; a regression equation of yarn quality indicators, and in addition to a three-dimensional surface chart, an optimal scheme of the roving twist factor and spinning drafting for a roving twist factor of 110 were established; a spinning back draft of 1.5 was obtained based on experimental results of the response surface analysis and variance regression analysis. Experiments on the optimal scheme were carried out to verify the practicability of the results obtained by this method. The results show that application of the multiple response surface method to the optimisation of process parameters is of practical significance. This method can be applied for the optimisation of other process parameters.

The fabrication procedure of tri-component elastic-conductive composite yarns (t-ECCYs) with distinctive architecture, which employs elastane filament as a core and stainless steel filament combining with rayon assemblies as a helical winding around the extensible core, was demonstrated. Then, a single factorial-analysis technique was applied to investigate the effects of processing variables, i.e., strand spacing, twist level and spindle speed, on some physical characteristics and spinning geometries of the resultant yarns, in terms of breaking tenacity, extension at break, elasticity, hairiness, unevenness, and visual features. Then, the electrical behavior was conducted. It is well established that the preparatory process variables play a significant role in deciding the physical characteristics of the final yarns. The Relationship between spinning geometries and yarn properties were highlighted. Experimental results revealed that the optimized physical performances of t-ECCYs were obtained at 10.5 mm strand spacing, 700 T/m twist, and 7000 rpm spindle speed. The resultant t-ECCYs could be a high-valuable proposition for special purposes in electrical textiles. The yarn itself is available as a base sensor element with substantial stretch and high conductivity, and such yarns could be easily processed into fabrics by conventional textile means offering fabrics with good shape preservation based on superior elasticity, even electromagnetic shielding effectiveness with metal monofilament inside, and can thus be applied as lightweight miniature electronics in the future.

The paper presents a method, which applied to the ring of the ring spinning machine will improve its productivity. Through the system vibration is applied on the ring-traveller, which has effects on the centrifugal force of the traveller and helps the traveller to rotate around ring with intermittent contact. The effect of vibration on yarn tension as well as friction between the ring and the traveler and the corresponding raise in temperature of the ring during spinning are measured. An external facility is designed and incorporated in a miniature ring spinning frame to generate and apply vibration to the ring. The miniature ring spinning frame has the facility to vary twist and count of yarn and is modified to vary the spindle speed. Study shows that the ringtraveller friction is affected by the application of vibration. Results obtained with and without the applications of vibration are compared. It is found that yarn tension and friction between the ring and the traveller reduce significantly depending on the type of vibration. Therefore it can be concluded that application of vibration may be a way to reduce friction between the ring and the traveler and thus the mechanical process of twisting and winding can be done at higher speed for higher productivity which is a limiting factor of ring spinning system. Bangladesh J. Sci. Ind. Res. 47(4), 421-426, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14072

The effects that spinning technology and spinning parameters have on the color strength (K/S), strength, and breaking elongation of post dyed and mercerized yarns are investigated in this study. The emphasis of the study is on the selection of long stable Egyptian cotton varieties, namely Giza 80, Giza 86, and extra long stable Giza 92. The cotton samples are spun by using compact, ring, and open end spinning technologies. For the purpose of this study, different yarn counts and twist multipliers are used. The mechanical properties, such as the tensile strength and breaking elongation of the produced yarn are investigated and compared before and after the mercerization treatment (slack and tension), followed by a reactive dyeing process. All of the samples are prepared for dyeing after mercerization. The dyeing performance in terms of the K/S is studied. When the results are examined, it is found that the samples that have undergone (bleaching + slack mercerization + reactive dyeing) generally have higher K/S values than samples that have undergone (bleaching + tension mercerization + reactive dyeing) and (bleaching + non-mercerization + reactive dyeing) respectively. Open-end spun yarns have a higher K/S compared to the compact and ring spun yarns with the lowest count yarn and twist level. The strength percentages are higher for compact, then ring and finally open-end spun yarns respectively with tension mercerization. There is no noticeable difference in the elongation% for all of the treatment processes. The authors have used quality engineering reproducibility and repeatability (R&R) tools to guarantee the repeatability and reproducibility of the results in this research paper.

Warp sizing is the precondition of weaving for most textile material. A key fact discussed in this paper is capillary effect, by means of a series of experiments known as observation of suction lift of various types of yarn under non-wetting and wetting condition, a longitudinal and cross section of warp under microscope, tensile breaking strength of sized warp compared between non-wetting sized warp and pre-wetting sized warp, desizing time, etc, it is concluded that the capillary effect is affected by textile material construction such as linear density of warp, spinning process, yarn twist, absorbency .etc, is inherent driving force for size glue penetrating into warp so as to make weaving possible, pre-wetting process will be greatly helpful for penetrating in warp slashing, resulted from capillary effect being enhanced

The end breakage rate (EBR), which is one of the most important quality variables used to determine the yield of a spinning process, depends on various process conditions and fiber/yarn properties. In the current study, historical data consisting of more than 10,000 runs from 55 ring spinning machines recorded under normal operation in YUNSA Worsted and Woolen Company in Turkey were analyzed using exploratory and predictive statistical techniques. Principal Component Analysis (PCA) was used to determine subsets of quantitative variables, which vary collectively, forming clusters for different machine types. Correspondence Analysis (CA) was found to be particularly beneficial to determine the association between machines and nominal variables, which make a significant contribution to product quality in textile industries. The current spinning process requires accurate discrimination between acceptable and faulty yarns, determined via a threshold on the EBR, so logistic regression was utilized for the prediction of faulty yarns. The Receiver Operating Characteristic curves showed that the discriminative capacity of the logistic models was at an acceptable level, almost on a par with that of Artificial Neural Network (ANN) models. For different types of machines, while yarn count, roving count, lot size, twist level and composition were commonly present in logistic models, the magnitude of their partial effects varied significantly. In conclusion, PCA, CA and logistic regression are suggested, along with ANN models, to be used for textile industries in online monitoring, detecting faulty machines, choosing optimum machines for specific operational conditions and determining the range of process variables for which controlled experiments may be required.

The novel hollow spindle with spiral guide grooves is introduced into the manufacture of Murata vortex spun yarn for the sake of enhancing the vortex yarn’s strength. By means of numerical simulation, the airflow characteristics in the conventional twisting chamber and novel twisting chamber of Murata vortex spinning are obtained and compared in order to explain yarn formation for adoption of the novel hollow spindle. The airflow distribution near the spiral guide grooves is analyzed, and the influence of airflow changes caused by the groove structure on the movement of the free end fibers and the yarn strength is analyzed. The results show that the spiral guide grooves will influence the pressure and velocity distribution in the twisting chamber, especially near the areas of the guide grooves. The guide grooves can guide the swirling airflow moving down the conical cavity of the twisting chamber, resulting in increases of the tangential, axial, and radial velocities of airflow in the conical cavity. And it is expected to produce fiber migration in the yarn cross-section and the self-twist effect of wrapped fibers. These phenomena will strengthen the wrapping and twisting effect of the free end fibers and inter-fiber cohesive force of vortex spun yarn in the process of yarn formation, and finally improve the strength of vortex spun yarn due to adopting the novel hollow spindle.

Rotor spinning is an open-end spinning method that uses air as the medium to transform the fibers into yarn. Nowadays, the properties of its final product—yarn—such as yarn strength and yarn twist, are not satisfied due to the fiber morphology, which greatly depends on the distribution of the massive fibers in the rotor spinning unit (RSU). In this paper, theoretical analysis is given to describe the trajectory of fiber on the slide wall. A numerical study is performed with the massive fibers being simplified into granules to study their distribution characteristics in the RSU. According to our numerical results, the forming process of the fibrous ring is discussed and the effects of two variables, the rotor speed and the angle of the slide wall, on the distribution of fiber granules were also studied. The simulation results indicate that the fiber granules are not evenly distributed during their transport in the fiber transport channel (FTC) and they tend to accumulate on the upper and lower edge of the FTC. The distribution of fiber granules in the groove (fibrous rings) is closely related to the rotor speed. The higher the rotor speed, the longer and thinner the fibrous ring. The distribution of fiber granules on the slide wall is related to the angle of the slide wall such that a smaller angle leads to a scattered distribution on the slide wall, while a larger angle tends to bring a concentrated one. The simulation results show good agreements with our experimental results.

Abstract This article reports the results of investigations carried out to produce yarns consisting of staple carbon fiber (CF) obtained from process waste for the manufacturing of composites suitable especially for thermoset applications. For this purpose, a comparative analysis is done on processability between 100% staple CF and 60 weight% staple CF mixed with 40 weight% PVA fibers in carding, drawing and spinning process. The hybrid yarns are produced by varying twist level. The PVA fibers of the hybrid yarn are then dissolved using hot water treatment. The mechanical properties of yarns consisting of 100% staple CF and hybrid yarns consisting of staple CF and PVA before and after hot water treatment are investigated. Furthermore, test specimen is also prepared by impregnating 100% staple CF yarn and the hybrid yarns (after the dissolving of PVA) with epoxy resin. The results of the tensile test of the yarns in consolidated state reveals that the hybrid yarn produced with 80 T/m after hot water treatment exhibits approximately 75% of the tensile strength of virgin filament tow, and it is expected that the hybrid yarns can be applied for the manufacturing of thermoset based composites for load bearing structures.

The denim, having a large customer base irrelevant of age, gender and social status limitation, has been one of the most important products for thegarment sector. Denim fabric demand has diversified with the changing consumer’s sense of life day by day. The denim manufacturers develop alternative production techniques and materials by turning towards new researches in order to adapt to consumer demands. One of the alternative materials, which are used in denim fabric structure, is the dual-core yarns. The dual-core yarn is manufactured through the modified ring-spinning machine in order to benefit at the same time from the properties of two core components. In this study the influence of some production parameters such as twist level, wool draft and elastane draft on the properties of dual-core yarns containing wool/elastane is investigated.The results indicated that the twist level is significantly effective parameter for the unevenness, hairiness, tenacity and elongation values of dual-core yarns. In addition, wool draft is significantly effective parameter for hairiness and breaking elongation values. It was also observed that variation of elastane draft level affects tenacity and elongation values of dual-core yarns.

This study aims to design a compact three-strand spinning approach as inspired by the twist and compact spinning. In the design process, auxiliary parts of twist and pneumatic compact spinning technologies were modified. First, a three-strand funnel and three-groove delivery cylinder were designed to feed three-strand into the drafting zone and control strand space. Then, air-suction guides and suction inserts with different structures of air-inlet slots were designed to create a separate condensing zone for each of the strands. Different structures of the air-suction guide and suction insert were used for modeling the compacting zone and four different systems were introduced. The effectiveness of compacting zones was discussed according to the numerical flow-field simulation studied with SolidWorks Flow Simulation software. Numerical simulation results showed that creating separate condensing zones for three-strand yarns was achieved with all of the new designs. However, the air-guide with longer air-inlet slot channels provided better flow-velocity components and static pressure values. It was also seen that using the same guide with narrowed slots suction insert results in greater flow-velocity components. In the experimental part, the guide with longer air-inlet slots and narrowed slots of suction insert was produced with a 3D printer and used for compact three-strand production. Properties of the compact three-strand yarns were compared with ring three-strand yarns to investigate compacting effects, and it was seen that better yarn properties were obtained with the compact three-strand spinning.

Purpose 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. Design/methodology/approach 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. Findings 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. Originality/value 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.

Ring is one of the major textile spinning machine consumable part, it has an important influence on yarn quality and cost. Ring of domestic cotton spinning enterprises generally has poor hardness, bad accuracy, not durable and difficult to guarantee the quality of the yarn, foreign ring has excellent performance, but it is too expensive, so it is difficult to widely used in China[1]. Vacuum arc ion plating technology has a wide range of applications in the aerospace, automobile, mold, tool, electronics and other fields [2-3]. TiN film which is prepared by arc ion plating technology has been widely used because of the TiN film has poor oxidation resistance and wear resistance at high temperatures, so the ternary films are developed on TiN film, such as TiAlN [4], TiCN etc. Traveller circle in the ring on the slide to produce large amounts of heat, it makes the ring surface temperature reach 400°C. When higher than 400°C, the TiCN film failure, therefore, ring should not be plated on the TiCN films. While TiAlN film oxidation temperature reaches 800°C. In HSS twist drill, depositing of TiAlN film can improve the service life more than four times [5]. Studies [6-8] have found that using pulsed laser deposition and chemical vapor deposition technique to prepare TiAlCN film, its wear resistance, high temperature stability is better. Pulsed laser deposition is mainly used in laboratory research. It is difficult to deposit a large area uniform film. Chemical vapor deposition of deposition rate is less than the arc ion plating, and produces lots of waste gas, leading to the environment is polluted. Arc ion plating technology can deposit the uniform films of large area with high deposition rate and deposition with no environmental pollution, therefore, this study, by means of vacuum arc ion plating technology to prepare high-precision, long-life and low-cost domestic cotton spinning ring. In order to obtain the best film process parameters, the performance of film is investigated at different bias and arc current.

It is difficult to introduce highly versatile automation using robots to handling deformable objects such as thread, cloth, wire, long beams, and thin plates in plant production processes, compared to the handling of rigid objects. Office equipment handles deformable objects such as paper and plastic. Problems unique to these objects is caused by speeding up such equipment and demand for upgrading its accuracy. In agriculture and medical care, automatic, intelligent handling of deformable objects such as fruit and animals has long been desired and practical systems sought. Deformable objects whose handling should be versatiley and accurately automated are classified into two groups based on handling: (A) Flexible, mostly thin, fine objects capable of elastic deformation (B) Soft objects easily crushed, such as soft fruits or animals The problem in handling the first group is controlling object deformation of an infinite degree of freedom with a finite number of manipulated variables. In contrast, a significant problem in handling the second group is often how to handle them without exerting excessive stress and how to handle them safely and reliably. The handling of these two groups differ greatly in mechanics and control theory, and this special issue focuses on the first group — flexible objects — mechanical collection and transport studies, control, and software. Recent studies on their handling are classified into four groups for convenience based on handled objects and types of handling task: (a) Control of deformation, internal force, and vibration or path planning of flexible objects (mainly thin plates and beams) using single or multiple manipulators. (b) Task understanding in insertion of elastic into rigid parts and vice versa, and the study of human skills to help robots accomplish these task. (c) Approaches on improved accuracy, intelligent control, and vibration damping in handling and transfer of sheets and strings with low flexural rigidity, represented by paper or wire. (d) Strategies for grasping and unfolding sheets such as cloth whose flexural rigidity is almost nil. For (a), studies are active on deformation control by two robot hands attempting to grasp cloth. 1-3) In the automobile industry, so-called flexible fixtureless assembly systems are advancing in which two robots process or assemble parts in mid-air without a fixed table to reduce lead time and cost. These systems are mostly developed assuming handled parts are rigid. Nguyen et al. work assuming parts such as sheet metal whose deformation must be taken into consideration.1) Nakagaki et al. propose form estimation that considers even plastic deformation in wire handling by robots, in connection with the development of robots for electric wire installation.4) Many studies cover flexible wire as elastic beams,3-9) but comparatively few focus on bending deformation of thin plates. This special edition includes a paper by Kosuge et al. on thin-plate deformation control. Vibration control of grasped objects becomes important as speed increases. Matsuno kindly contributed his paper on optimum path planning in elastic plate handling. In controlling the deformation of elastic bodies, the mechanics of objects handled is often unknown. This special issue features a paper by Kojima et al. on an approach to this problem by adaptive feed-forward control. For (b), we consider three cases: (1) A cylindrical rigid body inserted into a hole on an elastic plate. (2) An elastic bar inserted into a hole on a rigid body. (3) A tubular elastic body put on a cylindrical rigid body. This special issue carries papers on these problems by Brata et al., Matsuno et al., and Hirai. For (2), a paper by Nakagaki et al.10) covers electric wire installation. For (3), the paper by Shima et al.11) covers insertion of a rigid axis into an elastic hose. Robot skill acquisition is an important issue in robotics in general, and the above papers should prove highly interesting and information because they treat studies by comparing robot and human skills in accomplishing work and acquiring concrete skills knowledge. For (c), attempts are made to theoretically analyze sheet handling mechanisms and control developed based on trial and error, and to structure design theory based on such analysis. These attempts are related to the increased accuracy and speed and enhanced intelligence of sheet-handling office automation equipment such as printers, facsimile machines, copiers, and automated teller machines. Yoshida et al. conducted a series of studies on the effects of guides forming paper feed paths and of inertia force of paper by approximating sheets with a chain of discrete masses and springs.12-14) This special edition also features a study on sheet sticking and jamming. Okuna et al. handles a system of similar nature, mechanical studying the form of paper guides.15) Introducing mechanisms to control the positioning of sheets is effective in raising sheet transfer accuracy. Feedback control that regulates feed roller skew angle as a manipulated variable is proposed.16) Increased reliability in separating single sheets from stacked effectively reduces the malfunction rate in sheet-handling equipment. Ways of optimizing the form of sheet-separation rollers17) and estimating frictional force between separation gates and sheets 18) are also proposed. This special issue contains a proposal by Nakazawa et al. of a mechanism that uses reactive sheet buckling force, made in connection with development of a newspaper page turner for the disabled as technology for separating single sheets. Dry frictional force is most widely used for transporting sheets, but is not stable and may even act as an obstacle to improving accuracy. Niino et al. propose a sheet transfer mechanism that uses electrostatic force.19) For improving the accuracy of flexible wire transmission, this special issue carries a study on transporting flexible thin wire through tension control at multiple points, from a study by Morimitsu et al. on optical fiber installation. The thickness of wire used in equipment is becoming increasingly slim and flexible, along with the equipment it is used in. Tension control in the production process is an important factor in the manufacture of such thin wire. Production efficiency constantly calls for increased transfer speed. It has thus become important to estimate air resistance and inertia and to measure and control the tension of running wire. Studies20,21) by Batra, Fraser, et al. which deal the motion of string in the spinning process provide good examples for learning analytical techniques for air drag and inertia. In string vibration where inertia dominates, attempts are made to control vibration by boundary shaking22,23) and feed-forward/back control.24) For (d), highly versatile robots for handling cloth are being developed, and the software technology for automatic cloth selection and unfolding by robot hands is a popular topic.25-27) Ono et al. comment on the nature of problems in developing intelligent systems for handling cloth and similar objects whose bending rigidity is low and which readily fold and overlap—a paper that will prove a good reference in basic approaches in this field. Mechanical analyses are indispensable to studies on (a) through (c). In contrast, information technology such as characteristic variable measurement, image processing, and discrimination, rather than mechanical analyses, play an important roles in studies on (d). This special issue features a study by Hamashima, Uraya et al. on cloth unfolding as an example of such studies. Studies up to now largely assumed that properties of grasped objects did not change environmental influences such as temperature and humidity. Such influence is often, however, a major factor in handling fiber thread and cloth. This special issue has a paper contributed by Taylor, who studies handling method to prevent influence by such environmental factors. The objective of this special issue will have been achieved if it aids those studying the handling of flexible objects by providing approaches and methodologies of researchers whose target objects differ and if it aids those planning to take up study in this field by providing a general view of this field. References: 1) Nguyen, W. and Mills, J., ""Multi-Robot Control For Plexible Fixtureless Assembly of Flexible Sheet Metal Auto Body Parts,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2340-2345, (1996). 2) Sun, D. and Shi, X. and Liu, Y., ""Modeling and Cooperation of Two-Arm Robotic System Manipulating a Deformable Object,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2346-2351, (1996). 3) Kosuge, K., Sakaki, M., Kanitani, K., Yoshida, H. and Fukuda, T., ""Manipulation of a Flexible Object by Dual Manipulators,"" IEEE International Conference on Robotics and Automation, 318-323, (1995). 4) Nakagaki, H., Kitagaki, K., Ogasawara, T. and Tukune H., ""Handling of a Flexible Wire -Detecting a Deformed Shape of the Wire by Vision and a Force Sensor,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'96), 207-210, (1996). 5) Wakamatsu, H., Hirai, S. and Iwata, K., ""Static Analysis of Deformable Object Grasping Based on Bounded Force Closure,"" Trans. of JSML, 84-618 (C), 508-515, (1998). 6) Katoh, R. and Fujmoto, T., ""Study on Deformation of Elastic Object By Manipulator -Path Planning of End -Effector-,"" J. of the Robotics Society of Japan, 13-1, 157-160, (1995). 7) Yukawa, T., Uohiyama, M. and Inooka, M., ""Stability of Control System in Handling a Flexible Object by Rigid Arm Robots,"" JSME Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 169-172, (1995). 8) Yukawa, T., Uohiyama, M. and Cbinata, G., ""Handling of a Vibrating Flexible Structure by a Robot,"" Trans. JSME, 61-583, 938-943, (1995). 9) Sun, D. and Liu, Y., ""Modeling and Impedance Control of a Two-Manipulator System Handling a Flexible Beam,"" Trans. of the ASME, 119, 736-742, (1997). 10) Nakagaki, H., Kitagaki, K. and Tukune, H., ""Contact Motion in Inserting a Flexible Wire into a Hole,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 175-178, (1995). 11) Shimaji, S., Brata, A. and Hattori, H., ""Robot Skill in Assembling a Cylinder into an Elastic Hose,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 752-755, (1995). 12) Yoshida, K. and Kawauchi, M., ""The Analysis of Deformation and Behavior of Flexible Materials (1st Reprt, Study of Spring-Mass Beam Model of the Sheet,"" Trans. of JSME, 58-552, 1474-1480, (1992). 13) Yoshida, K., ""Analysis of Deformation and Behavior of Flexible Materials (2nd Report, Static Analysis for Deformation of the Sheet in the Space Formed by Guide Plates),"" Trans. JSME, 60-570, 501-507, (1994). 14) Yoshida, K., ""Dynamic Analysis of Sheet Defofmation Using Spring-Mass-Beam Model,"" Trans. JSME, 63-615, 3926-3932 (1997). 15) Okuna, K., Nishigaito, T. and Shina, Y., ""Analysis of Paper Deformation Considering Guide Friction (Improvement of Paper Path for Paper-Feeding Mechanism),"" Trans. JSME, 60-575, 2279-2284, (1994). 16) Fujimura, H. and Ono, K., ""Analysis of Paper Motion Driven by Skew-Roll Paper Feeding System,"" Trans. JSME, 62-596, 1354-1360, (1996). 17) Shima, Y., Hattori, S., Kobayashi, Y. and Ukai, M., ""Optimum of Gate-Roller Shape in Paper Isolating Methods,"" Conference of Information, Intelligence and Precision Equipment (IIP'96), 61-62, (1996). 18) Suzuki, Y, Hattori, S., Shima, Y. and Ukai, M., ""Contact Analysis of Paper in Gate-Roller Handling Method"", Conference on Information, Intelligence and Precision Equipment (IIP'95), 19-20, (1995). 19) Niino, T., Egawa, S. and Higuchi, T., ""An Electrostatic Paper Feeder,"" J. of the Japan Society for Precision Engineering, 60-12,1761-1765, (1994). 20) Batra, S., Ghosh, T. and Zeidman, M., ""An Integrated Approach to Dynamic Analysis of the Ring Spinning Process , PartII: With Air Drag,"" Textile Research Journal, 59, 416-424, (1989). 21) Fraser, W., Ghosh, T. and Batra, S., ""On Unwinding Yarn from a Cylindrical Package,"" Proceedings of Royal Society of London, A, 436, 479-438, (1992). 22) Jacob, S., ""Control of Vibrating String Using Impedance Matching,"" Proceedings of the American Control Conference (San Francisco),468-472, (1993). 23) Lee, S. and Mote, C., ""Vibration Control of an Axially Moving String by Boundary Control,"" Trans. of the ASME, J. of Dynamic Systems, Measurement, and Control, 118, 66-74, (1996). 24) Ying, S. and Tan, C., ""Active Vibration Control of the Axially Moving String Using Space Feedforward and Feedback Controllers,"" Trans. ASME, J. of Vibration and Acoustics, 118, 306-312, (1996). 25) Ono, E., Ichijo, H. and Aisaka, N., ""Flexible Robotic Hand for Handling Fabric Pieces in Garment Manufacture,"" International Journal of Clothing Science and Technology, 4-5,18-23, (1992). 26) Paraschidis, K., Fahantidis, N, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G, ""A Robotic System for Handling Textile and Non Rigid Flat Materials,"" Computers in Industry, 26, 303-313, (1995). 27) Fahantidis, N., Paraschidis, K, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G., ""Robot Handling of Flat Textile Materials,"" IEEE Robotics & Automation Magazine, 4-1, 34-41, (1997).

The twisting process of the sliver is an important part of the yarn spinning process, but this process has not been fully characterized on the fiber scale. Herein, based on the assumption that fibers are randomly distributed in the sliver, we analyzed the simulation twisting process of the sliver model on the fiber scale. The mathematical model of the twisting process of the sliver is set up and the non-free-end twisting process is simulated using the finite element software ABAQUS®. The simulation process clearly shows the configuration changes of the sliver caused with the increase of the twist. We also divided the twisting process into 11 stages and obtained a three-dimensional model of staple yarn. Then, the relationship curve between the ring-spun yarn fineness and the number of fibers in the cross-section of the ring-spun yarn was established by spinning the yarns of different counts of 20, 25, 30, 35, 40, 45, 50, 55, 60 and 65 Ne, and the fineness of the simulated yarn was calculated. The accuracy of the simulated yarn was verified by comparing the weight of the simulated yarn and the ring-spun yarn. The model established can be used to predict yarn properties for different purposes and can also be further utilized to study other phenomena in ring-spinning technology.

The spinning triangle is an important area in the spinning process, and the shape of the spinning triangle influences the yarn qualities. This paper aims to theoretically study the effects of the spinning parameters on the shape of the spinning triangle. In this paper, a model of the spinning triangle considering force equilibrium and torque equilibrium was built. The initial strain of fibers in the spinning triangle was determined by the profile of the spinning triangle. The initial height of the spinning triangle was obtained by the width of the spinning triangle and the twist angle. Based on the initial condition and boundary condition in the model, the displacements of the twisting point were obtained. With the displacements of the twisting point, the height of the spinning triangle and the deviation angle of the center fiber in the final spinning triangle, which represent the shape of the spinning triangle, were calculated. In the analysis, the spinning tension, yarn twist, and yarn radius were chosen as the independent parameters to analyze the geometric change of the spinning triangle.

Abstract Lateral compact spinning with pneumatic groove is a spinning process to gather fibers by common actions of airflow and mechanical forces. Compared with ring spinning, it can more effectively reduce yarn hairiness and enhance yarn strength. However, fiber motion in the agglomeration area is complex. And, it is important to establish a new fiber model to accurately describing the fiber motion. The objectives of this research were to create a new fiber model to simulate the agglomeration process, to analyze yarn properties of the lateral compact spinning with pneumatic groove, and to compare with other spinning yarns through a series of tests. The new fiber model was based on the finite element method implemented in MATLAB and was to show the fiber motion during the agglomeration area. The simulation generated results were close to the real motion of fibers in spinning. In the lateral compact spinning with pneumatic groove, fiber bundle through the agglomeration area can be gathered, and the output of the fiber bundle was nearly to cylinder before yarn twisted. The experiments demonstrated that the lateral compact spinning with pneumatic groove can improve the yarn properties: increase the yarn twist, enhance the yarn strength, and reduce the yarn hairiness.

At present, there have been a significant number of studies of segment colored yarn, and the majority of these studies have made considerable progress, which has made the types and styles of segment colored yarn more abundant. However, the problem that exists in the segment colored yarn is its relatively few kinds of color, which greatly limits its flexibility and diversity in commercial applications. To address the above problems, a multi-channel computer numerical control (CNC) ring-spinning machine was developed, and a digital spinning mechanism with online regulation of the forming linear density and blending ratio was constructed through the developed three-channel drafting mechanism and its driving and controlling system; the spinning mechanism of segment colored yarn using the time-varying three-channel drafting ratio to the spinning time-varying three-colored fiber blending ratio was established by implementing a coupling algorithm for co-drafting of multi-channel roving; the forming process and algorithm of segment colored yarn, which is used to solve the blending ratio of three colored fibers and the drafting ratio of three-channel roving based on segment color, was constructed through the digital color mixing model and the design of segment color of yarn. According to the above mechanism, three rovings with two color combinations of cyan, magenta, yellow and cyan, magenta, black were used to design and spin segment colored yarns with three, five and seven colors, respectively. By testing and analyzing the linear density, twist, unevenness, surface hairiness and tensile properties of the segment colored yarn, it is proved that the timing control of the three-channel drafting ratio based on CNC ring spinning can achieve the timing control of the blending ratio of the three colored fibers, which is beneficial to the spinning of segment colored yarn with color segment distribution.

Hairiness is a prominent property of staple yarns, but the existing evaluation parameters mainly describe the fiber ends already protruding out of yarn bodies. The potential fiber ends in yarns also play a crucial role in the performance of yarns in the subsequent processes and the resultant fabric quality. In our previous studies, maximum hairiness and its theoretical model have been proposed, which indicate the maximum fiber ends of a staple yarn having the potential to protrude out of yarn bodies and become hairy. On this basis, the relative hairiness index (RHI) is developed in this study to evaluate the fiber end tucking and securities of yarns. This index is treated as a ratio of the measured hairiness of sample yarns and the maximum hairiness of ring yarns in the same twist level and yarn count. A lower RHI indicates more fiber ends being tucked into yarn bodies, and a slower increment of the RHI with the increasing winding times represents more stable securities of fiber ends in yarns. The experimental results demonstrate that the RHI can directly reveal the effectiveness of different spinning parameters and methods in tucking and securing fiber ends; also, the changes of the RHI with increasing winding times visually present the stableness of fiber ends in various yarns experiencing abrasion, as well as predict the possibility of the potential fiber ends being pulled out to form hairiness during successive processes. The proposed RHI, therefore, provides a significant reference for the spinning process design and yarn quality control.