A novel method to reduce hairiness level of ring spun yarn

The quality of ring spun yarns is largely determined by its level of hairiness. The existence of hairiness inevitably affects the quality of ring spun yarns. This paper presents an innovative method on lowering the level of hairiness of ring spun yarns. This can be achieved by shooting compressed air to the yarn, through a swirl nozzle comprising a yarn duct and an airjet nozzle attached to a traditional ring spin frame. When compressed air is applied from the air-jet nozzle to the yarn duct, the swirling air flow tucks surface fibers of the ring spun yarns into its body. Four controllable variable parameters for the process, supplied pressure, nozzle position, twist factor and spindle speed, and their effects on the lowering of yarn hairiness will be clarified. Their impact on the quality of the yarn is statistically analyzed, and the optimum outcome of the combination of parameters for the process, will thus be determined.     

Reducing ring spun yarn hairiness via spinning with a contact surface

In this study, spinning with a contact surface was introduced as a simple and energy-saving method to reduce spun yarn hairiness. Theoretical analysis indicated that yarn hairiness could be reduced via a sufficient long contact surface applied in other part of yarn formation zone in addition to spinning triangle. Then, a simple contact apparatus was installed on ring frame to validate the theoretical analysis. Results proved that yarn hairiness was reduced via a contact surface in the yarn formation zone. However, unevenness was deteriorated for most yarns spun with contact apparatus during the spinning, which might be due to fiber mass concentration. Most of yarns spun with contact apparatus had a lower strength than the conventional yarns. This might be because evenness deterioration to decrease yarn strength overpowered hairiness reduction to increase yarn strength for most yarns spun with a contact surface.     

An experimental study of influence of filament and roving location on yarn properties during embeddable and locatable spinning

This study was focus on the influence of filament and roving location on yarn properties during embeddable and locatable spinning (ELS). ELS composite yarns were produced with various filament and roving locations on an experimental ring spinning frame. Besides yarn formation zone configurations, ELS yarn properties were compared including yarn hairiness, unevenness and tensile properties. Results showed that spinning triangles became larger; however, the reinforced composite spinning strand length kept constant. With a constant filament-roving spacing on each side of ELS, Filament spacing variations caused no significant changes of spun yarn hairiness, tenacities, imperfections and unevenness CV. For roving location variations with constant filament spacing, the reinforced strand length became longer as the roving spacing increased. Hairs exceeding 3 mm were lower for ELS yarn spun with 4 mm and 10 mm roving spacings than that spun with 6 mm, 8 mm and 12 mm roving spacings. Roving spacing variations had a trivial influence on ELS yarn unevenness; whereas, yarn tensile index variation coefficients fluctuated dramatically due to hairiness variations for different roving spacings.     

Effect of repeated winding on carded ring cotton yarn properties

In this study, ten carded ring spun cotton yarns were subjected to windings. Yarn hairiness, fineness, unevenness and tensile properties were then examined. Results showed that the majority of the increased yarn hairiness occurred at the beginning cycles of windings. Weight loss occurred for most yarns after repeated windings. Tensile properties deteriorated for nearly all the yarn samples after repeated windings. On the contrary, yarn unevenness was improved for most yarns after corresponding windings. To explain the better evenness of yarn after repeated windings, unevenness of yarn was divided into two parts, namely stem unevenness and surface hairiness unevenness; yarn imperfections were subdivided into two categories: the imperfections of yarn stem and the imperfections caused by yarn hairs. Specifically, a balanced opinion was given to discuss the gains and losses in quality and cost due to repeated windings.     

A study on siro-jet spinning system

Nowadays, there is ever increasing interests regarding with the nozzle usage in spinning systems and also winding process. In this study, an air nozzle was attached on to the sirospun spinning system and the system was called as siro-jet. Sirospun is a spinning system combining spinning and doubling in one operation and a yarn like a two fold is produced. The principle of the siro-jet system is based on the placement of the nozzle at the exit of drafting unit on sirospun spinning system and pressurized air was fed into the nozzle by the compressor during the spinning. In literature, air nozzle application in this manner is not common and hence the system is very less known. For that reason, siro-jet and siropun yarns were produced with different fibre types, material qualities and yarn counts, and the properties of the yarns were compared. At the end of the study, it was determined that siro-jet spinning system truly improves the yarn hairiness in comparison to sirospun spinning system. Even, the siro-jet yarns are less hairy after winding process. Interestingly, hairiness results of siro-jet and sirospun yarns produced with short, non-uniform fibres showed that siro-jet spinning system allows working with low cost raw materials while maintaining yarn quality. Therefore, siro-jet can be considered as an innovative spinning system regarding with less hairy yarn production opportunity.     

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 (21^S), 18.2 tex (32^S) and 14.6 tex (40^S), 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.     

Study on characteristics of compact yarns under dynamic state

The dynamic testing conditions simulate actual manufacturing conditions more closely than static testing. In most cases, as results from dynamic tests differ significantly from static tests, dynamic tests are more relevant from the point of view of processing of yarn. The yarns are in motion when they are running on different machines during the production process viz. weaving; knitting etc. Compact ring spun yarns have created a fundamental change how the industry views the ring spinning. The new technology compact yarns such as EliTe® yarns need to be compared with the normal doubled yarns in a dynamic way. This study involves dynamic testing of the EliTe® compact yarns and normal ring spun doubled yarns using CTT (Constant Tension Transport) machine, a versatile test instrument to measure the yarn properties such as dynamic breaking strength, elongation, abrasion, lint, yarn faults (thick, thin places, neps), hairiness etc. EliTe® compact yarns showed higher breaking strength, more elongation, with lesser yarn faults and hairiness, less abrasiveness and less lint generating tendencies during the dynamic testing as compared to the normal ring spun doubled yarns.     

Study on the static and dynamic strengths and weavability of spun yarns

This study reports on the analysis of tenacity and breaking elongation of ring-, rotor- and air-jet-polyester/viscose spun yarns measured using static- and dynamic tensile testers. The weavability, a measure of performance of these yarns in post spinning operations is quantified. The yarn diameters and helix angles of fibres in these yarns are measured in order to analyze the effect of types of spun yarn and blend proportion on yarn elongations. The dynamic tenacity is highly correlated with the weavability than the average static tenacity measured at 500 mm gauge length. The minimum static tenacity obtained from 100 tests has high correlation with the dynamic tenacity. The present study indicates that it is appropriate to evaluate the performance of spun yarns in winding, warping and weaving based on the dynamic yarn tenacity measured while running a 200 m length of yarn in a constant tension transport tester or the minimum static yarn tenacity obtained using any conventional constant rate extension (CRE) tensile testers corresponding to a total test length of 50 m.     

Yarn setting and hairiness reduction with a steam jet during winding

This paper examines the use of pressurized steam for wrapping and setting the yarn hairs concurrently via a new steam-jet process during winding. Yarn torque can also be stabilized as an added advantage. The results obtained with two batches of pure wool yarns suggest that there is potential to achieve yarn hairiness reduction of up to 60 % with minimum deterioration in hairiness even after subsequent rewinding.     

用喷气-环锭和喷气-络筒技术减少麻纱线毛羽的研究

喷气-环锭和喷气-络筒是一种简单、低成本的减少纱线毛羽的新方法。我们对其进行理论和实验研究。采用数值模拟的方法，对毛羽在喷嘴内的运动进行模拟，说明了利用喷嘴减少毛羽的机理。根据数值模拟的结果，我们预测了喷嘴参数对减少毛羽的影响，并以麻纱为对象，用实验的方法研究了喷气-环锭和喷气-络筒技术对减少纱线毛羽的效果以及参数影响，实验与理论研究的结果相符。     

An experimental investigation of yarn tension in simulated ring spinning

Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed rig, which can rotate a yarn at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yarn rotating speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions, a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns.     

The effect of spinning parameters on mechanical and physical properties of core-spun yarns produced by the three-strand modified method (TSMM)

The effect of spinning parameters on core-spun yarns properties manufactured using three-strand modified method (TSMM) was analyzed. Of the various spinning parameters, strand spacing, yarn linear density and yarn twist have a crucial effect on core-spun yarn properties. To achieve the objectives of this research, general physical properties of core-spun yarns together with existing standards were thoroughly studied. First of all, the strand spacing and yarn linear density were optimized. Afterwards, the effects of variation of yarn twist and sheath roving linear density on core-spun yarns properties were investigated. Finally, the physical and mechanical properties of TSMM yarns were compared with those of siro and conventional ring core-spun yarns counterparts. It was found that, the best strand spacing and yarn linear density to produce core-spun yarns are 8 mm and 45 tex, respectively. Results showed that, tenacity of TSMM yarns increases up to a certain twist level beyond which it reduces. The result confirmed that 45 tex yarns produced by three rovings of the same count are superior with regards to tenacity and hairiness. The optimized yarns produced by three-strand modified method enjoy superior physical and mechanical properties in comparison to the ring and siro core-spun yarns.     

利用喷嘴减少苎麻纱毛羽的探讨

本文从喷嘴在纺纱中的几个实例出发，根据它们产品毛羽少的共性，在苎麻纺纱实验中采用了喷嘴与环锭纺的方法，以期减少苎麻环锭纱的毛羽。     

Structural analysis of finer cotton yarns produced by conventional and modified ring spinning system

Yarn structure plays an important role in determining the properties of spun yarns. Recently, a modified spinning technique has been developed for producing a low torque and soft handle singles yarn by modifying the fiber arrangement in a yarn. Comparative studies revealed that the finer modified yarns possess significantly higher strength and lower hairiness over the conventional yarns of the same twist level, implying a different structure of finer modified yarn. Thus this paper aims to quantitatively study the structures of the finer conventional and modified cotton yarn (80 Ne) produced at the same twist level. Various measuring techniques, namely the Scanning Electron Microscope (SEM), cross section technique and tracer fiber technique, are adopted to analyze their structural characteristics, including fiber configuration, fiber spatial orientation angle, fiber packing density, yarn surface appearance, and fiber migration behavior. Results showed that finer modified yarns exhibit a smoother surface and much more compact structure with less hairiness. The fibers in the finer modified yarn have a complicated fiber path with relatively lower fiber radial position, larger migration frequency and magnitudes. In addition, it was noted that 73% of fibers in the finer conventional yarn follow concentric conical helix, which is contrary to those in the coarser conventional yarn. The analyses conducted in this paper provide deep insights into the mechanism of modified spinning technique and evidential explanations on the difference of properties between the finer conventional and modified yarns.     

Influence of the core-sheath weight ratio and twist on the tensile strength of the ring core yarns with high tenacity filaments

Core spun yarns are applied for various purposes that especially require the multi-functional performance. This research reports on the core spinning effect on the yarn strength. We prepared various core yarns by combining different kinds of high tenacity filaments in core with cotton staples in sheath with various twist levels in the ring spin system. And the tensile strength was tested to investigate the contribution of the core-sheath structure to the core yarn strength. The influence of the twist level was also checked up on the relationship between the core-sheath structure and the yarn strength. Results turned out that the core-sheath weight ratio had influence on the tensile properties of the ring core-spun yarns in different ways according to the core filaments used for the yarn. Increasing the twists yielded a monotone decreasing strength for the aramid and the basalt core yarns, while the PET core yarns showed almost unchanged strength, which could be ascribed to the extensional property of the filaments.     

Performance of cotton single yarns and knitted fabrics produced by a 2-step spinning method

A low torque spinning method has been recently developed by integrating the ring spinning process with false twisting techniques. As a result of false twist and true twist, a novel single yarn of low torque and soft handle is generated. Based on the similar spinning principle, this paper proposed a 2-step spinning method, which is composed of twisting-anduntwisting operation and can be considered as a variant of the low torque spinning method. The proposed spinning method separates the false twisting process into twisting and untwisting processes which are combined in one step in the low torque spinning method. In this paper, physical properties of yarns produced by the proposed spinning method were evaluated and compared with the conventional yarns. Influences of various spinning parameters on the properties of 2-step yarns were also examined. Furthermore, a systematic study of the physical properties of the 2-step yarns and resultant fabrics with respect to the conventional and low torque ones was carried out. The experimental results showed that the 2-step yarns exhibit slightly higher tenacity, lower wet snarl and much less hairiness than the conventional yarns, which, however, are inferior to the low torque yarns, particularly the evenness. The fabrics made by the 2-step yarns show the softest handle feeling, best airpermeability and moderate spirality angle with acceptable pilling resistance.     

Continuous twisted nanofiber yarns fabricated by double conjugate electrospinning

In order to fabricate continuously twisted nanofiber yarns, double conjugate electrospinning had been developed using two pairs of oppositely charged electrospinning nozzles. The principle and process of this novel yarn spinning method were analyzed, and the effect of applied voltage, nozzle distance between positive and negative, solution flow rate and funnel rotating speed on the diameters, twist level and mechanical properties of resultant PAN nanofiber yarns were investigated in this paper. The results indicated that electrospun nanofibers aggregated stably and bundled continuously at the applied voltage of 18 kV, the nozzle distance of 17.5 cm between positive and negative, the overall flow rate of 3.2 ml/h and the flow ratio of 5/3 for positive and negative nozzles. The resultant nanofiber yarns had favorable orientation and uniform twist distribution, and the twist level of nanofiber yarns increased with the increase of the ratio of funnel rotating speed and winding speed. The diameters and mechanical properties of nanofiber yarns depended on their twist level. The diameters of prepared PAN nanofiber yarns ranged from 50 µm to 200 µm, and the strength and elongation of PAN nanofiber yarns at break were 55.70 MPa and 41.31%, respectively, at the twist angle of 41.8 °. This method can be also used to produce multifunctional composite yarns with two or more components.     

Effects of bleaching and dyeing on the quality of alpaca tops and yarns

This paper reports the effects of bleaching of alpaca tops and dyeing of bleached alpaca tops/yarns on the quality of tops and yarns. A dark brown alpaca top was bleached with hydrogen peroxide. Two bleaching methods were tried for effectiveness of color removal. A portion of each bleached top was dyed after bleaching. Color parameters were examined for unbleached, bleached and bleached/dyed tops, these tops were then converted into yarns of different twist levels and counts using a worsted spinning system. Some of the bleached yarn from each bleaching method was dyed in a package dye vat to compare the difference of top dyeing versus yarn package dyeing on yarn quality. Fiber diameter, yarn strength, yarn evenness, yarn hairiness and fiber degradation were tested to examine the effects of bleaching and dyeing on these properties at top and yarn stages. A processing route for bleaching and dyeing alpaca fiber was recommended.     

Effect of vortex tube structure on yarn quality in vortex spinning machine

In order to study the effect of the structure of vortex tube on the yarn performance in jet vortex spinning, 8 groups of vortex tube structure were designed, and the corresponding 3D computational fluid dynamic models were established to numerically simulate the airflow in the nozzle. Through analysis of the characteristics of air flow inside the different nozzles, such as pressure distribution and velocity vectors, the motion of drafted fibers and performances of yarns were discussed. Simulation results show that when the structure of vortex tube has a transition region between the cylindrical and conical cavity (CCT) and the outlet of jet orifice is located at the junction of cylindrical and transition cavity, the airflow state within the nozzle has a large negative pressure with appropriate axial and tangential velocity, which is conducive to the formation of the open-ends of fibers and twisting, and the yarn quality turns out to be better. Spinning experiment results prove that the yarn strength reaches the maximum value, while the unevenness of breaking strength meets the minimum, and the other yarn properties are superior, which shows a good agreement with the simulation results. Thus, the numerical simulation can provide the theoretical as well as quantitative reference for the vortex tube design in the coming future.     

Application of TOPSIS approach on parameters selection problem for rotor spinning machine

Classical statistical analysis has been generally used in obtaining optimum condition such as problems for rotor spinning machine. In these methods the preferences of the producer about yarn characteristics to achieve the desired end product properties have not been taken into consideration. However, machine parameters selection from possible alternatives with different performance levels about yarn quality is difficult task and is inherently a multi-criteria decision making problem. In the present study, valuable assistance in reaching acceptable solutions in order to select the appropriate doffing tube and its adjustment for 30 Ne rotor yarn spun to raise efficiency of weft knitting machine will be provided by technique for order preference by similarity ideal solution (TOPSIS) approach. In experimental part 30 Ne rotor yarn samples were spun by considering one quantitative variable, i.e., two different distances between the nozzle and rotor, and also two qualitative variables, i.e., nozzles in 4 different shapes and a draw-off tube with and without a torque stop. Then quality parameters of the yarns were analyzed with TOPSIS.