An artificial neural network-based hairiness prediction model for worsted wool yarns

This study evaluated the performance of multilayer perceptron (MLP) and multivariate linear regression (MLR) models for predicting the hairiness of worsted-spun wool yarns from various top, yarn and processing parameters. The results indicated that the MLP model predicted yarn hairiness more accurately than the MLR model, and should have wide mill specific applications. On the basis of sensitivity analysis, the factors that affected yarn hairiness significantly included yarn twist, ring size, average fiber length (hauteur), fiber diameter and yarn count, with twist having the greatest impact on yarn hairiness.

The hairiness of worsted wool and cashmere yarns and the impact of fiber curvature on hairiness

In this study, a range of carefully selected wool and cashmere yarns as well as their blends were used to examine the effects of fiber curvature and blend ratio on yarn hairiness. The results indicate that yarns spun from wool fibers with a higher curvature have lower yarn hairiness than yarns spun from similar wool of a lower curvature. For blend yarns made from wool and cashmere of similar diameter, yarn hairiness increases with the increase in the cashmere content in the yarn. This is probably due to the presence of increased proportion of the shorter cashmere fibers in the surface regions of the yarn, leading to increased yarn hairiness. A modified hairiness composition model is used to explain these results and the likely origin of leading and trailing hairs. This model highlights the importance of yarn surface composition on yarn hairiness.

Characterization of conductive polyprrole coated wool yarns

Wool yarns were coated with conducting polypyrrole by chemical synthesis methods. Polymerization of pyrrole was carried out in the presence of wool yarn at various concentrations of the monomer and dopant anion. The changes in tensile, moisture absorption, and electrical properties of the yarn upon coating with conductive polypyrrole are presented. Coating the wool yarns with conductive polypyrrole resulted in higher tenacity, higher breaking strain, and lower initial modulus. The changes in tensile properties are attributed to the changes in surface morphology due to the coating and reinforcing effect of conductive polypyrrole. The thickness of the coating increased with the concentration of p-toluene sulfonic acid, which in turn caused a reduction in the moisture regain of the wool yarn. Reducing the synthesis temperature and replacing p-toluenesulfonic acid by anthraquinone sulfonic acid resulted in a large reduction in the resistance of the yarn.

Conductive wool yarns by continuous vapour phase polymerization of pyrrole

Conducting polypyrrole (PPy) coated wool yarns were prepared by a continuous vapour polymerization technique, using a speed of 1 m/min with different iron(III) chloride (FeCl₃) as the oxidant at different concentrations. The resistivities, tensile properties, longitudinal and cross-sectional views of PPy-coated wool yarns were investigated. Optimum specific electrical resistances of 2.96 Ω g/cm² at 80 g/L FeCl₃ and 1.69 Ω g/cm² at 70 g/L FeCl₃ were obtained for 500 and 400 twist per meter (TPM) yarns, respectively. PPy-coated wool yarns exhibited higher elongation than uncoated yarns. Longitudinal and cross-sectional views of the yarns indicate that PPy coating penetrated deep into the yarn cross-section and a uniform coating was obtained on the surface of the yarn surface.

Conducting nylon, cotton and wool yarns by continuous vapor polymerization of pyrrole

Conductive textile yarns were prepared by a continuous vapor polymerization method; the application of polypyrrole by the continuous vapor polymerization method used is designed for the easy adaptation into industrial procedures. The resultant conductive yarns were examined by longitudinal and cross-sectional views, clearly showing the varying levels of penetration of the polymer into the yarn structure. It was found that for wool the optimum specific resistance was achieved by using the 400 TPM yarn with a FeCl3 solution concentration of 80 g/L FeCl3 to produce 1.69 Ω g/cm2. For cotton yarn, the optimum specific resistance of 1.53 Ω g/cm2 was obtained with 80 g/L of a FeCl3 solution.

A controlled experiment on yarn hairiness and fabric pilling

This study focused on the hairiness of worsted wool yarns and how it affects the pilling propensity of knitted wool fabrics. Conventional worsted ring spun yarns were compared with comparable SolospunTM yarns and yarns modified with a hairiness reducing air nozzle in the winding process (JetWind). Measurements of yarn hairiness (S3) on the Zweigle G565 hairiness meter showed a reduction in the S3 value of approximately 46% was achieved using SolospunTM ring spinning attachment and a 33% reduction was achieved using the JetWind process. Interestingly, subsequent evaluation of the pilling performance of fabrics made from the SolospunTM spun yarn and JetWind modified yarn showed a half grade and full grade improvement, respectively over a similar fabric made from conventional ring spun yarns. This result suggested that a relatively large reduction in yarn hairiness was needed to achieve a moderate improvement in fabric pilling, and that the nature of yarn hairiness was also a key factor in influencing fabric pilling propensity. It is postulated that the wrapping of surface hairs by the air vortex in the JetWind process may limit the ability of those surface fibers to form fuzz and reach the critical height required for pill formation.

The new solo-siro spun process for worsted yarns

The aim of this paper was to explore whether the properties of worsted yarns, especially hairiness, can be improved by combining the Solospun and Sirospun processes into a single Solo-Siro spun process. Wool fibres of 19 and 21 μm in average diameter were spun into 40 tex yarns at different twist levels, using the conventional ring, Sirospun and Solo-Siro spun systems, respectively. These yarns were then tested for a range of properties, including hairiness, tenacity, elongation and evenness, for comparison purposes. The statistical analysis results indicate that the hairiness (S3 value) of Solo-Siro spun yarns was significantly less than that of both Sirospun and normal ring spun yarns. In addition, the tenacity of the Solo-Siro spun yarns was higher than that of the normal ring spun yarns, while changes in yarn breaking elongation were not statistically significant. For the 21 μm wool, it was found that the evenness of Solo-Siro spun yarns deteriorated slightly in comparison with that of Sirospun and conventional ring spun yarns.

Investigation of yarn hairiness

Yarn hairiness affects not only the quality of products, but also the productivity in spinning and weaving. Too much yarn hairiness is undesirable for many end uses as well as the spinning and post spinning processes. The main aims of this project are to examine the hairiness features of various yarns and to reduce yarn hairiness. The thesis covers five related areas – hairiness assessment, factors affecting yarn hairiness, the hairiness of newly developed yarns, yarn hairiness reduction, and effect of yarn hairiness on the energy consumption in ring spinning. The worsted cashmere, pure wool and wool/cashmere blend yarns were employed to investigate the effect of some fibre parameters on the yarn hairiness. A single exponential distribution of the hair-length was confirmed first, using the data from the Zweigle G565 Hairiness Meter. A linear relationship was observed between the blend ratio and the hairiness indexes. In particular, the effect of fibre crimp or curvature on yarn hairiness is examined. The theory of yarn hairiness composition was also developed further. The effect of draft ratio and spindle speed on the hairiness of worsted wool yarn was examined next with a factorial experiment design. Several new hairiness indexes, namely the relative hairiness indexes, have been used to explain the results obtained. In the investigation of the hairiness of newly developed yarns, the hairiness of the Compact Spun and Roller-Jet-Spun yarns was examined first. The composition of the yarn hairiness, the hair-length distribution, and the effect of test speed on yarn hairiness were then studied. An important finding is that for both yarns, the predominant hairiness feature is the looped hairs. A comparison of the hairiness of Solospun yarns and the equivalent ring spun wool yarns was undertaken. The hair-length distribution of the Solospun yarn was examined first. The Solospun yarns used had fewer hairs in most hair-length groups and lower variations in hairiness. In addition, the effect of twist level and spindle speed on the hairiness of Solospun and conventional ring spun yarns has also been discussed. A novel approach of reducing yarn hairiness – spinning with a ‘Diagonal’ yarn path was examined next. Both ‘Left Diagonal’ and ‘Right Diagonal’ yarn arrangements were studied. A new finding is that the ‘Right Diagonal’ yarn path leads to reduced hairiness for the Z-twist yarn, while yarn evenness and tenacity are not as sensitive to the modified yarn path. The mechanism of hairiness reduction with the ‘Diagonal’ yarn path has been discussed. The spinning performance of “Right Diagonal” yarn arrangement has also been evaluated. Finally, the effect of yarn hairiness on the energy consumption in ring spinning has been investigated theoretically and experimentally. A theoretical model has been developed, which represents the first attempt at theoretically investigating the influence of yarn hairiness on energy consumption during the winding stage of ring spinning. The experimental results have generally confirmed predictions of this model. Recommendations for further research in this area have also been made in the concluding chapter of this thesis.

Estimating the diameter of yarns with irregular constituent fibres

Yarn diameter and packing density are difficult to measure directly. Existing models on fibre packing density in a yarn assume that all fibres are uniform and have an identical diameter. Yet real staple yarns, such as wool yarns, consist of fibres of varying diameters. This paper proposes an effective and simple yarn model for calculating the average diameter of yarns, in which fibres have circular cross-section and the close packing in the yarn cross-section. The concept of “area equivalent diameter” is introduced to transform fibres of varying diameters to identical fibres with one equivalent diameter to simplify the calculations of the average yarn diameter for a range of yarns.

The influence of yarn parameters on the ultraviolet protection of yarns

 Improving ultraviolet (UV) protection of textiles is essential to protect wearers against UV radiation induced risks. In addition to fabric parameters, yarn parameters are important factors affecting UV protection of textiles. This work is to examine the influence of yarn parameters on UV protection in order to set up a statistical model for predicting the UV protection of yarns. Wool yarns with different variables were used to test the ultraviolet protection factor (UPF) values for data analysis and the model verification. The model provides the optimized parameters for the UV protective fabric design. This work is helpful as a pre-cursor to the development of a more advanced optical model, which will look at understanding the penetration of UV light through fibres, yarns and fabrics.

The effect of yarn hairiness on air drag in ring spinning

Air drag on yarn and package surfaces affects yarn tension, which in turn affects energy consumption and ends-down in ring spinning. This study investigated the effects of yarn hairiness on air drag in ring spinning. Theoretical models of skin friction coefficient on the surface of rotating yarn packages were developed. The predicted results were verified with experimental data obtained from cotton and wool yarns. The results show that hairiness increases the air drag by about one-quarter and one-third for the rotating cotton and wool yarn packages, respectively. In addition, yarn hairiness increases the air drag by about one-tenth on a ballooning cotton yarn.

Simulation and experimental validation of a ring spinning process

Ring spinning is the most important system of making high quality yarns in the textile industry. Yarn tension affects yarn breakage, which in turn affects yarn productivity in ring spinning. Accurate information about how various spinning parameters affect yarn tension is essential for the optimisation of the ring spinning process. In this paper, a program to simulate the ring spinning process was developed using MATLAB, which can predict yarn tension under given spinning conditions. The simulation results were verified with experimental results obtained from ring spinning cotton and wool yarns.

Recent studies on yarn tension and energy consumption in ring spinning

High energy consumption remains a key challenge for the widely used ring spinning system. Tackling this challenge requires a full understanding of the various factors that contribute to yarn tension and energy consumption during ring spinning. In this paper, we report our recent experimental and theoretical research on air drag, yarn tension and energy consumption in ring spinning. A specially constructed rig was used to simulate the ring spinning process; and yarn tension at the guide-eye was measured for different yarns under different conditions. The effect of yarn hairiness on the air drag acting on a rotating yarn package and on a ballooning yarn was examined. Models of the power requirements for overcoming the air drag, increasing the kinetic energy of the yarn package (bobbin and wound yarn) and overcoming the yarn wind-on tension were developed. The ratio of energy-consumption to yarn-production over a full yarn package was discussed. A program to simulate yarn winding in ring spinning was implemented, which can generate the balloon shape and predict yarn tension under a given spinning condition. The simulation results were verified with experimental results obtained from spinning cotton and wool yarns.