Thin Places Research Articles

Investigation on the properties of blended rotor-spun cotton/polyester yarn using a hybrid model

In this study, the interaction between blended rotor-spun yarns of cotton and polyester fibers has been investigated using the hybrid model. Various blends of PET/CO were produced and tensile and evenness properties of yarns were examined. The migration index of yarns has been calculated to study how migration affects the yarn properties. The difference between the experimental values and predicted values has been studied statistically using the rule of mixtures. The results of the tenacity of yarns have been compared with Hamburger's model. The results show that elongated and thin places have no significant difference in the rule of mixtures model. Tenacity, work of rupture, and hairiness are decreased in blended yarns while the uniformity, thick places, and neps are increased. The tenacity of the yarns does not follow the Hamburger's model. The migration index shows that cotton fibers tend to migrate inwards and the migration index of this fiber is minimum at 75:25 and maximum at 50:50 PET/CO blended yarns.

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.

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.

Analysis of spinning process using the Taguchi method. Part V: Effect of spinning processvariables on physical properties of ring, rotor and air-jet yarns

Effect of lap hank and drafts, of various spinning sequence of machines, was studied on physical properties of different yarns using Taguchi method and analysis of variance. The ring yarn is highly even and has the least number of thin places and neps but thick places are the least in rotor yarn. The air-jet yarn is the least even and has the highest number of thin places, thick places and neps. The total hairiness is the least on rotor yarn and number of hairs =3 mm (S3) the least in ring yarn. In air-jet yarn the total hairiness and S3 are the highest. The finer lap hank and higher card draft in preparatory process produces even ring and rotor yarns with lower hairiness. However, the higher speed frame draft improves the evenness of yarn produced from coarser lap hank and lower card draft. Lower ring frame, rotor and high air-jet draft improves the properties of the respective yarns. Increase in ring/air-jet draft increases S3.

Measuring the influence of fibre-to-fabric properties on the pilling of wool fabrics

This study ranks the contribution of various fibre, yarn and fabric attributes to the pilling of wool knitwear. On the basis of an artificial neural network modelling, a combination of sensitivity analysis, forwards/backwards search and genetic algorithms was used to identify the importance of various fibre/yarn/fabric input parameters. The three different techniques show broad similarities in their assessment of which input parameters are important or are not important in affecting fabric pilling. The ranking shows that fabric cover factor has the most effect on pilling, followed by yarn count and thin places, fibre length, yarn twist, etc. It is further illustrated that the directional trend of the predicted pilling outputs for a selection of inputs was in line with the expected behaviour. To verify the findings of input feature selection, input factors deemed to have a small effect on the predicted pilling output, such as fibre length and diameter variations and curvature, were removed and the subsequent performance statistically compared to the original multi-layer perceptron. Differences between the outputs predicted by the original and pruned models are found not to be statistically significant at the 5% significance level. Results from this study may help manufacturers and knitwear designers in choosing the most appropriate materials and structures to reduce the pilling propensity of wool knitwear.

Listening in Thin Places

Healthcare professionals may see prolonging life and use of scarce resources as futile if the quality of life of persons with Alzheimer's disease is deemed to be poor. Thus, nurses and other healthcare providers need to question traditional assumptions of quality of life. This article presents a phenomenological study of ethical concerns related to quality of life as described by persons with Alzheimer's disease, family caregivers, and professional caregivers. The theme of "Creating a Quality of Life Through Connected Lives" calls forth an ethics of respect for the individual experience and its connecting relationships.

Mill specific prediction of worsted yarn performance

Different spinning mills use different raw materials, processing methodologies, and equipment, all of which influence the quality of the yarns produced. Because of many variables, there is a difficulty in developing a universal empirical/theoretical model. This work presents a multilayer perceptron algorithm (MLP) model for the purpose of building a mill specific worsted spinning performance prediction tool. Sixteen inputs are used to predict key yarn properties and spinning performance, including number of fibers in cross-section, unevenness (U%), thin places, neps, yarn tenacity, elongation at break, thick places, and spinning ends-down. Validation of the model on mill specific commercial data set shows that the general fit to the target values is good. Importantly, the performance of the MLP shows a certain degree of stability to different, random selections of independent test data. Subsequent comparison against the predicted outputs of Sirolan Yarnspec™ confirms the overall performance of the artificial neural network (ANN) method to be more accuratefor mill specific predictions.

Quantitative Grading of Spun Yarns for Appearance

The general appearance of a yarn is one of the primary qualities affecting its commercial value. The method of grading spun yarns by subjective visual examination has long been recognized as a practical quality assessment tool in yarn manufacturing and fabric forming industries.In this paper, we want to report an objective and quantitative method for grading spun yarn appearance derived from optical yarn diameter measurements. Our study found that quantitative yarn characteristics derived from the optical yarn diameter measurement are determining factors for a human vision system to differentiate a good yarn from a bad one in terms of appearance. These characteristics are the optical yarn diameter, the yarn diameter CV%, thick place size, thin place size, nep size and yarn diameter distribution. We obtained a robust numerical metric (objective discriminatory appearance index) for yarn appearance grade, which is a linear combination of the numerical characteristics derived from the optical yarn diameter data of the USDA graded Ne 20 (29.5 Tex) Grade A, B, C and D yarns described in ASTM D2255-90.

End Breaks in the Spinning and Weaving of Weavable Singles Yarns

An end break will occur in spinning when the tension in the balloon exceeds the strength at the weakest point in the yarn, which is at the point of twist insertion and before the fibers are fully twisted together. Other than gross faults such as slubs, the cause of an end break is generally a very thin place, the incidence of which can be estimated from the mean linear density of the yarn and its variance. A good correlation was found between the end breakage rate and the irregularity (CV%) of the yarn, which appears to be independent of yarn count. The tenacity of the yarn at a break was estimated to be only about 1.85 g/tex. For wool yarns which are woven in the warp as singles, end breaks in spinning effectively remove those thin places which are likely to break in warp ends during weaving. It is recommended that such yarns be spun at high speed to remove those short, very thin places which might not be detected in clearing, but which may fail in weaving.

End Breaks in the Spinning and Weaving of Weavable Singles Yarns

The eight weavable singles yarns studied in Part 1 of this paper were all woven plain weave and the end breaks identified by cause and recorded. End breaks were found to be due to failed splices, abrasion failure and thin places. The incidence of thin-place breaks was found to increase with increasing irregularity (CV%) of the yarn, and as the linear density of the yarn decreased. It is primarily the thin-place end breakage rate which determines the yarn count limit for acceptable weavability, and this is shown to depend on the evenness of the yarn. It is shown how to predict the thin-place end breakage rate from the yarn, fabric and loom parameters.

Predicting Yarn Processing Performance from the Noncellulosic Content of Raw Cottons

Noncellulosic materials on raw cottons can influence spinning performance. Chemical and physical tests are conducted on a series of nonsticky single-season upland cottons originating from three U.S. growing areas. Relationships are determined between yarn production performance and efficiency and fiber frictional and physical properties as well as nonfibrous material content for three different spinning systems. Fiber micronaire significantly influences results. Increases in yarn strength correlate with increasing levels of total fiber alcohol surface extractables, wax, and potassium content. Processing ends down increases in ring and open-end spinning and decreases in vortex spinning as fiber alcohol surface extractables, wax, and light metal content increase. Ends down decrease in ring an open-end spinning and increase in vortex spinning as the HVI trash measurement increases. Uster yarn evenness neps and thick and thin places decrease in ring and open-end and increase in vortex yarns as alcohol surface extractables increase. Fiber yellowness and grayness increase as concentrations of the metals potassium, magnesium, and iron increase.

A Qualitative Approach to Estimating Cotton Spinnability Limits

Cotton spinnability, or spinning potential, is traditionally determined based on the number of ends-down occurring under controlled spinning conditions. No yarn quality considerations are included in this spinning potential concept, which is representative only of the performance of a given fiber during spinning. Using measurements of thin places in ring spun yarns as the surrogate variable representing yarn quality, a new "quality potential" component is added to the traditional spinnability notion. Spinnability limits are o determined on the basis of yarn quality, and a new spinning potential definition that captures both critical aspects of spinning performance and yarn quality is advanced.

THE INFLUENCE OF COTTON NONCELLULOSIC NATURALLY OCCURRING MATERIALS ON YARN PROCESSING PROPERTIES

Cotton fibers contain naturally occurring noncellulosic materials such as sugars, wax, metals, and other organicspecies that may significantly affect textile yarn manufacturing efficiency, processing performance, and quality. Chemicaland physical tests were conducted on raw cottons from different U.S. growing areas to determine the effect of different concentrationsof these materials and fiber frictional properties on rotor and ring spinning performance and yarn properties. Yarnbreak factors and single yarn strengths were found to increase, and evenness thick and thin places were found to decrease,as levels of ethyl alcohol extractions, the metals potassium and magnesium, and RotorRing friction increased. Yarn strengthsdecreased and thick and thin places increased in ring spinning as levels of the metal calcium increased. Ring yarn neps increasedand rotor yarn neps decreased as alcohol extractions, wax levels, potassium and magnesium content, and fiber tometal friction increased.

EFFECTS OF RAW COTTON NONCELLULOSIC CONTENT AND FIBER ROTORRING FRICTION ON YARN RING SPINNING PERFORMANCE

In the manufacturing of cotton textile goods, especially with modern high speed processing machinery, fibernoncellulosic surface related materials and naturally occurring metals may have significant effects on yarn spinningefficiency and product quality. Chemical and physical tests were conducted on cottons originating from five domestic growingareas to determine reducing sugars, wax, total noncellulosic extractable contents, individual residual metal contents, andfrictional measurements to determine possible correlations between these properties and ring yarn spinning productionperformance. Adjusted skein-break factor, single yarn strength, and long thin place measurements were found to be highlyrelated to fiber ethyl alcohol surface extractable materials and the total light metal content. Yarn yellowness (+b) was highlyrelated to metal content. Process carding wastes correlated with increased raw fiber ash residues, potassium content, and thefiber-to-fiber friction measurement.

Weavability limit of yarns with thickness variation in shuttleless weaving

Theoretical weavability limit relationships of fabrics from regular warp yarns and fancy filling yarns with thickness variation in shuttleless weaving are reviewed. The relationships correlate maximum warp and filling cover factors, warp and filling yarn characteristics, the distribution of thick and thin places of filling yarn over the fabric surface, and the warp and filling weave factor. The research considers single filling feeder and multiple feeders cases. Additionally, comparisons between the weavability limit of regular yarns and fancy yarns in shuttle and shuttleless weaving are given.

Modifying Dew-Retted Flax Fibers and Yarns with a Secondary Enzymatic Treatment

Preliminary studies by atomization test the application of various kinds of enzymes as a means of tailoring dew-retted flax fibers in a low moisture atmosphere. A series of chemical and physical tests determines the effect of enzymes on fibers and blended yarns (50:50 flax : cotton). GLC analysis of post-treatment fiber washes shows that lipase and cellulase release the most sugars, likely due to structural disorganization of the fiber matrix. Glucose is the sugar most released by enzyme treatment. Mid-infrared spectros copy of fibers indicates the loss of carbohydrates and the presence of absorbed proteins following all enzyme treatments. All treatments reduce fiber strength and elongation compared to untreated fibers, with cellulase reducing fiber strength the most at 56% of the untreated control. Treatments reduce the occurrence of thick and thin places but reduce yarn strength as well. In general, lipase and arabinanase treatments influence yarn properties the most by increasing strength over the buffer-only treatment, increasing elongation over untreated and buffer-treated yams, and reducing neps and thick/thin places. These preliminary results suggest strategies to optimize enzyme treatments for improved textile properties.

Ethics: The Ethics of Diversity: A Call for Intimate Listening in Thin Places

Ethics: The Ethics of Diversity: A Call for Intimate Listening in Thin Places

The Effect of Fixed Flats on Yarn Quality

An investigation is reported in which the effect of fixed flats fitted to a cotton card on fibre orientation, revolving-flat load, and strip was studied. A modified Krylov method was used to assess the effects of production speed and of fixed flats on the cylinder load, the fibre-transfer coefficient, and the fibre orientation. Two fibre types, cotton and polyester fibre, were used. The use of fixed flats was found to be beneficial in reducing sliver nep content. However, the rear fixed flats were found to have no effect on the yarn's Uster-evenness value, whereas the use of front fixed flats was found to reduce thin and thick places significantly.

Going Home—: The Road to Paint Lick

Going Home— The Road to Paint Lick The huge white steer at the fence Stares at me like a flabby Buddha His rump and thigh muscles Bulging and I have A sudden urge to stroke The thick flap of his Adam's apple What would his flesh be like Against my skin? And in the next field Three stallions gallop They take off their sleek bodies Brown and glistening in the sun A yellow brown haze rises And I wonder what it would be like If I pressed my second finger down Against the thin place Between their eyes? Would they wince? Or nuzzle against my skin? The road winds toward home And feathery almond green leaves Shimmer in the wind Like thin shards of glass A knot tightens in my throat I ask for words I know There once were words In the hollows of my heart On my lips I often spoke them In the quiet open spaces where My flesh touched the world —Jan Zlotnik Schmidt 14 ...

Effects of Feed Sliver Moisture Content on Rotor Spinning Performance and Rotor Spun Yarn Properties

The aim of this study is to determine if high feed sliver moisture content will improve spinnability in rotor spinning without deteriorating yarn properties. Yarns are produced at a high rotor speed and low twist level. Two different count rotor spun yarns (18's and 24's) are spun from 100% cotton sliver at two different feed sliver moisture contents and two different opening roller speeds. Results indicate that high moisture content reduces the number of ends down, but increases yarn unevenness and the frequency of thin places, thick places, and neps. In addition, yarn elongation and work-to-break results are worse at high moisture content during spinning. In the case of fine yarn, a high opening roller speed tends to improve spinnability by reducing the number of ends down. Yarn evenness and thin and thick place results are also better. Overall, the results suggest that feed slivers with high moisture content can provide better spinning performance in rotor spinning. In other words, high moisture content can increase the production rate of open-end rotors, thus reducing the production cost of rotor spun yarns. However, a high moisture content also tends to deteriorate yarn evenness, increase the frequency of imperfections, and decrease yarn elongation.