Effect of two separate fibre feed systems in rotor spinning on yarn properties

Opening of the fibres in all industrial rotor spinning units is being done by an opening roller, which intakes the fibres from one feed point. Increasing number of feed rollers from one to two may improve fibre opening on the opening roller by gradual loading of the opening roller, which may improve fibre orientation in the final yarn and yarn properties. In this research a modified SE-8 rotor spinning unit of Suessen was used in which two separate fibre feed systems were employed. Raw material used was 38 mm, 1.7 den viscose fibre, to spin a 40 tex yarn. Yarn properties produced with this unit, were compared with that of the original yarn. Yarn properties tested were tenacity, extension, work of rupture, mass irregularity and imperfections, abrasion resistance and hairiness, which were measured on Shirley (SDL) and keisokki yarn testing machines. Test results were analyzed by ANOVA for any difference between the means, and Tukey and Duncan for classification and ranking of the yarn properties. Test results showed that, tenacity, extension and work of rupture of the modified yarn increased in comparison to the original yarn. Its mass irregularity, number of thin places and neps, and hairiness decreased. Number of thick places and yarn abrasion didn’t change. According to the test results, it was concluded that increasing the number of feed rollers on the opening roller from one to two has improved yarn properties.     

Effect of braid structure on yarn cross-sectional shape

The effect of braid construction parameters on yarn cross-sectional shape is presented in this paper. The location of the yarn within the braid unit cell is quantified by a compaction factor. A range of braided fabrics were produced and optically measured for actual yarn cross-sectional shape. A comparison of the theoretical and experimental values shows good correlation. Design curves can be produced with the developed model to allow selection of appropriate braid process parameter to create yarns with desired cross-sectional geometries.     

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.     

Effects of spinning processes on HVI fiber characteristics and spun yarn properties

The effects of opening, carding, and repeated drawings on single fiber and bundle cotton characteristics were studied by employing Mantis®, AFIS® and HVI Testers. Some of the significant changes in single fiber properties were found to be due to process parameters as well as the changes in the fiber crimps, parallelness of fibers within HVI beards, and the actual changes in the tensile properties of the fibers. The study showed that the HVI test data taken just prior to spinning had the highest correlation with the yarn tensile properties. Based on the study results, we point out the potential of HVI for future quality and process control in spinning by recommending a set of expanded HVI output that is more scientific and comprehensive for the future control needs.     

Properties of wool/spandex core-spun yarn produced on modified woolen spinning frame

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yarn. However it’s difficult to produce wool/spandex core-spun yarn on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yarn produced in this way has good appearance and quality by comparing with normal yarn. A series of experiments were carried out to study the influence of spandex drafting ratio and yarn twist factor on tensile properties and elasticity of core-spun yarns. The results indicate that core-spun yarn with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.     

Design of traverse cam for yarn winding on twisting machine

A twisting machine is to twist yarns for improving yarn strength. After twisting yarns, the twisting machine winds yarns into a bobbin. The traverse mechanism is very important part of winding mechanism. Because it performs uniform winding onto the bobbin. the traverse cam is the main part of the traverse mechanism. This paper proposes design method of the traverse cam using the relative velocity method [4,5]. The relative velocity method is used to calculate the relative velocity of the follower versus the cam at the center of roller, and then to determine the contact point using the geometric relationship and kinematical constraints. Finally, we present examples verifying the accuracy of the proposed methods.     

Studies on reduction of yarn hairiness by nozzles in ring spinning and winding by airflow simulation

Reduction of yarn hairiness by nozzles in ring spinning and winding is a new approach. Simulation of the airflow pattern inside the nozzles provides useful information about actual mechanism of hairiness reduction. The swirling air current inside the nozzles is capable of wrapping the protruding hairs around the yarn body, thereby reducing yarn hairiness. Since production rate of winding is very high and the process itself increases yarn hairiness any method to reduce the hairiness of yarns at this stage is a novel approach. A CFD (computational fluid dynamics) model has been developed to simulate the airflow pattern inside the nozzles using Fluent 6.1 software. In this study, both S- and Z-type nozzles having an axial angle of 50° and diameter of 2.2 mm were used for simulation studies. To create a swirling effect, four air holes of 0.4 mm diameter are made tangential to the inner walls of the nozzles. S- and Z-twisted yarns of 30 tex were spun with and without nozzles and were tested for hairiness, tensile and evenness properties. The total number of hairs equal to or exceeding 3 mm (i.e. the S3 values) for yarn spun with nozzle is nearly 49–51 % less than that of ring yarns in case of nozzle-ring spinning, and 15 % less in case of nozzle-winding, while both the yarn types show little difference in evenness and tensile properties. Upward airflow gives best results in terms of hairiness reduction for nozzle-ring and nozzle wound yarns compared to ring yarns. Yarn passing through the centre of the nozzle shows maximum reduction in S3 values.     

纺纱方式对长绒棉高支纱性能的影响

为明确不同长绒棉纤维适纺性能及不同纺纱方式下的成纱质量,以新疆5个长绒棉品种(系)(新海35号、新海53号、新海57号、丰海8号、丰海7号)的纤维为原料,采用普通环锭纺和紧密纺2种纺纱方式,纺100S纯长绒棉纱,并对成纱性能进行测试.结果:与环锭纺相比,紧密纺大大提高了成纱的强伸性能,降低了3 mm毛羽指数,改善了条干...     

Prediction of cotton yarn properties using support vector machine

This paper presents a support vector machine (SVM) regression approach to forecast the properties of cotton yarns produced on ring and rotor spinning technologies from the fibre properties measured by HVI and AFIS. Prediction performance of SVM models have been compared against those of the artificial neural network (ANN) models. A k-fold cross validation technique is applied to assess the expected generalization accuracies of both SVM and ANN models. The investigation indicates that the yarn properties can be predicted with a very high degree of accuracy using SVM models and the prediction performance of SVM models are better than that of ANN models.     

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.     

Effect of chemical softening of coconut fibres on structure and properties of its blended yarn with jute

Coconut fibres were subjected to chemical treatment to obtain softer and finer fibres, suitable to blend with other finer fibre like jute. The chemical softening recipe was optimized using Box-Behnken design of experiments as 40 % Na₂S, 10 % NaOH and 6 % Na₂CO₃, which notably reduced the fineness (33 %) and flexural rigidity (74 %) and improved tensile property of coconut fibre. Effect of softening of coconut fibre on its process performance was studied in high speed mechanized spinning system at different blend ratios with jute. Blending with jute assists in spinning of coconut fibre to produce yarn of 520 tex at production rate of 5-6 kg/h, as compared to 15 kg/day for hand spun 5300 tex raw coconut fibre yarn in manual system. Analysis of blended yarn structure in terms of packing density, radial distribution of fiber components (SEM) and mass irregularity were investigated. SEM shows yarns made from softened coconut fibre -jute blends are more compact than raw coconut fibre -jute blend yarns. Coconut fibres were preferentially migrated to core of the yarn. Major yarn properties viz., tensile strength, and flexural rigidity of raw and chemically softened blended yarns were compared against their finest possible 100 % coconut fibre yarn properties. Yarn made up to 50:50 chemically softened coconut fibre-jute blend showed much better spinning performance, and having superior property in terms of reduced diameter, higher compactness, strength, initial modulus and less flexural rigidity than 100 % raw, 100 % chemically softened coconut fibre rope, and raw coconut fibre-jute blend yarns.     

Wicking properties of polyamide 66 twisted nanofiber yarn by tracing the color alteration in yarn structure

In view of the interest in wicking properties of these flexible structures, analysis of the wicking phenomena in nylon 6.6 nanofiber yarns is carried out by considering the twist rate effects. A novel method is used based on adding a pH-sensitive dye to yarn interstructure and the analysis of color alteration of nanofiber yarn structure, resulting from a shift in pH, during the capillary rise of distilled water. The results show that the addition of pH- sensitive dye has no influence on the average nanofiber diameter and the wicking behavior of yarns. This study shows that in short durations, the kinetic of the capillary rise follows the Lucas-Washburn equation. The Lambertw, a mathematical function, has been incorporated, which helps measure an equivalent structural factor of nanofiber yarns and vertical wicking height at any given time considering the gravitational effects. The statistical results show that the average of equilibrium wicking height and capillary rise rate coefficient tend to decrease with increasing the nanofiber yarn twist, due to the reduction of continuity and size of capillaries.     

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 fiber friction, yarn twist, and splicing air pressure on yarn splicing performance

The impact of fiber friction, yarn twist, and splicing air pressure on mechanical and structural properties of spliced portion have been reported in the present paper. The mechanical properties include the tensile and bending related properties and, in the structural properties, the diameter and packing density of the splices are studied. A three variable three level factorial design approach proposed by Box and Behnken has been used to design the experiment. The results indicate that there is a strong correlation between retained spliced strength (RSS) and retained splice elongation (RSE) with all the experimental variables. It has been observed that RSS increases with the increase in splice air pressure and after certain level it drops, whereas it consistently increases with the increase in yarn twist. The RSE increases with the increase in both fiber friction and yarn twist. It has also been observed that the yarn twist and splicing air pressure have significant influence on splice diameter, percent increase in diameter and retained packing coefficient, but the fiber friction has negligible influence on these parameters. Yarn twist and splicing air pressure has a strong correlation with splice flexural rigidity, where as poor correlation with retained flexural rigidity.     

Effect of bio-friendly conditioning agents on jute fibre spinning

From early times, jute fibre has been generally conditioned for easy spinning by adding oil and water in the form of an emulsion. The commonly used oil consists of C₁₂–C₃₁ fractions of mineral oil that sometimes impart different intensities of oily (kerosene) or fishy smell to the end product. In the present work, efforts have been made to find a suitable sustainable substitute of mineral oil based conditioning agent for spinning of jute yarn and for this, three types of vegetable oil (rice bran oil, palmolein oil and castor oil), a silicone emulsion, a mixed enzyme system and glycerine have been used separately or in combinations as conditioning agents for jute fibre before its mechanical processing for making yarn in jute spinning machines. Considering comparable mechanical process performance for spinning of jute fibre (viz., fibre loss as droppings during processing, moisture retention prior to spinning stage and spinning end breakage rate), tensile properties of yarn, and lower yarn hairiness, it may be suggested to use 2.5% castor oil alone, or 2% castor oil in combination with 0.1–0.5% glycerine in the form of oil-in-water emulsion as the most suitable alternatives to conventional mineral oil-based jute conditioning agent to spin ordinary jute yarn.     

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.     

Effect of polystyrene mixing on mechanical properties and structural changes in melt spinning

To increase the spinning speed of poly(trimethylene terephthalate) (PTT) fibers, polystyrene (PS) was selected as an additive polymer in the PTT matrix. Mixing of the immiscible PS with PTT led to an increase in spinning speed up to 5,500 m/min. PS was employed to improve the extensibility of the matrix PTT in the spinning process as it can prevent PTT molecular orientation. Experimental results show that the mixing of PS achieved this. The elongation at break of spun fibers increased with the amount of PS. PS addition prevented fiber orientation, especially amorphous orientation, and improved drawability, and as such, increased spinning speed up to 5,500 m/min.     

Impact of yarn extension on packing density of ring spun yarn

The present paper deals with a detailed study on the effect of progressive yarn extension on diameter, overall packing fraction, radial packing fraction at different radial positions and partial packing fraction at different segments along the length of a fibre. An image processing based system to characterize and visualize the configuration of fibers in yarn in extended mode has been adopted. It has been observed that with the increase of yarn extension at different intervals, yarn diameter continuously decreases but at different yarn extension intervals, the percentage decrease value in the yarn diameter is different. But the packing density of yarn does not follow the exact trend of yarn diameter with the extension of yarn at different intervals. The yarn packing density initially increases at very high rate, then at very low rate and finally the packing density of yarn rather slightly decreases with the increase in yarn extension. The radial packing density of the yarn is not uniform across the cross-section of the yarn and it is not maximum near the yarn axis, rather it is maximum at some distance from the yarn axis. The location of maximum radial packing densities of yarn changes with the yarn extension. The partial packing density along the length of yarn is not uniform and the results are equally applicable for all level of yarn extension.     

名优茶鲜叶原料分级机研究

名优茶鲜叶原料分级机研究表明,采用本研究自制的名优茶鲜叶原料分级机,可对机采茶叶进行有效分级,经分级的原料,较好地实现了以芽叶大小分级归类,从中可获得较为整齐一致一芽二叶为主的名优茶生产原料。不同展叶状态的芽叶其个体大小差异大,以个体大小作为分级方式,所获的同一等级原料中会出现不同展叶状态的芽叶。     

振动理条对针形名茶品质的影响

近年来，随着国内外茶叶市场的不断发展变化，机制针形名茶以其外形紧直，滋味醇爽等品质优势深受广大饮茶爱好者欢迎。在加工过程中，振动理条技术直接关系到机制针形名茶的外形品质，同时，它也是提高茶叶产品内质的重要工序。但在生产上，由于一些生产者使用振动理条机时间不长，加工方法把握不当，导致生产出来的茶叶很难达到名茶的品质要求。本试验以鸡鸣卵叶茶为试验……