• Textile Coloration and Finishing
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• 제23권1호
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• pp.35-42
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• 2011

For high quality DTP products, it is important to optimize the parameters of media, pre- and after-treatment, ink, printer, etc. This study investigated the effect of types of fabrics(media) as a DTP parameters. Especially, the effects of media properties such as yarn twist and knitted fabric structure, on printability and color difference were examined. Two types of cotton yarn twist(830 and 1630 twist/meter) and five knitted structures of media were prepared with a single circular knitting machine. The K/S values of hard-twist samples were higher than those of normal-twist samples in every media structures. It is more effective to use the knitted fabrics of a hard-twist yarn to obtain dark color in the printing above input level value 60 where the printability improvement was most pronounced in case of plain structure. Among the five media structures a plain structure was the highest and that of corduroy was the lowest in terms of K/S values. Also ${\Delta}E$ values and lightness of the hard-twist yarn samples were smaller than that of normal-twist yarn samples when ${\Delta}E$ values were tested by using a standard of a normal twist yarn sample with a plain structure, which was increased in the case of corduroy structure.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1091-1091
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• 2001

Previous reports have shown that Near Infrared Spectroscopy (NIRS) can be used to assess physical and chemical properties of flax fibre and fabric quality. Currently, spinners assess yarn quality mainly based on strength and regularity measurements. There two key characteristics are influenced by quality of raw fibres used, especially the degree of rotting and strength. The aim of this investigation was to evaluate the use of NIRS for assessing quality of weft grade yarn available on the commercial market. In order to develop the NIR calibrations, a range of samples representing poor, medium and good quality weft yarn samples was included in the calibration and validation sample sets. The samples were analysed for physical and chemical parameters including caustic weight loss, fibre fractions, lipid, ash and minerals. A detailed protocol for assessing yarn quality has been developed to maximize the accuracy of the reflectance spectra. The development of partial least squares regression models and validation of the calibration equations using blind samples will be presented and discussed.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제57권11호
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• pp.2054-2060
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• 2008

This paper aims at the performance enhancement of tension controller for the yarn manufacturing process. The tension controller is required to keep the tension constant while the yarn is manufactured by a draw and twist machine, which is essential and critical for good quality production of yarn, steel, paper, etc. This paper proposes a linear model of tension control plant to develop a precise tension control system, which is derived by the close observation of the conventional mathematical model of motor driving and tension control systems. It is shown by experiments that the proposed control system precisely maintains the tension constant within the error bound of 0.05% while the conventional PI controller has about 0.2% error. The control performance of the system has been compared to that of conventional PI control not only for constant speed control but also for transient speed control experiments.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 한국감성과학회 2002년도 춘계학술대회 논문집
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• pp.16-19
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• 2002

Random and/or periodic defects occur in all spun yarns. These irregularities can often lead to defects in finished fabric. Yarn evenness tests are used to obtain statistical data about yarn properties, such as CV%, which is useful in comparing several sets of similar data that differ in mean value but may have some commonality in relative variation. Although this statistical data is helpful in determining relative yarn Quality, accurate predictions of how the yarn will appear in fabric form are still difficult to obtain. As an promising alterative, wavelet analysis has been employed to localize yam defect so as to predict the visual qualifies of the fabrics.

• Textile Coloration and Finishing
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• 제12권2호
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• pp.89-95
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• 2000

Effect of twist-setting time, temperature and cylinder layer for the physical properties of the twist yarn were investigated by separated 9 layer from yarn cylinder. Obtained results were as follow. Shrinkage of the yarn in middle layer shows high value with heat-permeation and in inner's shows low value because of cylinder hardness. And then yarn thermal shrinkage in outer layers shows more or less high value because twist yarn in the outer layer sets more faster. Concerning to the difference on the yam physical properties among cylinder layers, the changes on physical properties shows significant differences from the 7th layer to the last one. Linear density, T.P.M and initial modulus decreases but snarl index increases.

• Science of Emotion and Sensibility
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• 제5권3호
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• pp.35-38
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• 2002

Random and/or periodic defects occur in all spun yarns. These irregularities can often lead to defects in finished fabric. Yarn evenness tests are used to obtain statistical data about yarn properties, such as CV%, which is useful in comparing several sets of similar data that differ in mean value but may have some commonality in relative variation. Although this statistical data is helpful in determining relative yam quality, accurate predictions of how the yarn will appear in fabric form are still difficult to obtain. As an promising alterative, wavelet analysis has been employed to localize yarn defect so as to predict the visual qualities of the fabrics.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.67-70
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• 2010

Spandex yarn requires a twisting process during winding and unwinding processes at the textile industry. The air-twist nozzle is widely used as part of the winding and unwinding. This paper describes computational approach to design the geometry of the air-twist nozzle. The nozzle has circular yarn-channel and the air-inlet which is perpendicularly connected to the yarn-channel with yarn-loading slit. The air-inlet of the nozzle is designed while measurements of the yarn-channel are fixed. The airflow inside the air-twist nozzle is simulated by using Computational Fluid Dynamic model. The Ansys CFX was used to perform steady simulations of the airflow for the air-twisting process. The vortical structure and the airflow pattern such as velocity streamline, vorticity, velocity of the air-twist nozzle are discussed. Computational results are compared with experimental results in this paper.

• Proceedings of the Korean Society For Composite Materials Conference
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.95-98
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• 2003

In woven or knitted preforms for composites, the yams are often twisted for avoiding damage due to the contact with the textile machine elements. When the preforms of twisted yams are used in carbon/carbon composites, the thermal conductivity of the composites varies depending upon the degree of the yarn twist. This paper presents a thermal conductivity model of spun yarn composites. The thermal-electrical analogy and the averaging technique have been adopted in this analysis. The model prediction has been correlated with experimental results in order to confirm the model predictability. Parametric study has also been conducted to examine the effect of the yam twist on the thermal conductivity of spun yarn composites.

• Fibers and Polymers
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• 제7권2호
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• pp.213-216
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• 2006

The effect of cashmere yarn twist, knitted fabric density, and cashmere properties on pilling rates of cashmere knitted fabric is investigated in this paper. The experimental results show that yarn twist and fabric density have little influence on pilling rates of cashmere knitted fabric for yarn 38.4 tex/2 when yarn twist varies from 234 T/m to 272 T/m, and the fabric density is 9.7, 10.7, and 11.2 yarns/inch, respectively. The length of cashmere fiber, in particular less than 7.5 mm, is responsible for the pilling rates of cashmere knitted fabric based on optimal scaling regression analysis.

• Fibers and Polymers
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• 제4권3호
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• pp.119-123
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• 2003

Fluff (lint, fiber fly) generation, especially related to yarn structure, was investigated. Research centered on the fiber length related to fluff generation during the knitting process. Short fiber length composing yarn structure was a main source of the fluff shedding. High quality spun yarn with longer length of fiber was recommended to the high speed knitting industry in order to reduce process troubles such as yarn breakage, etc. but the cost is doubtable to the manufacturers. A trial to reduce the fluff trouble by using chemicals to hold the short fiber on the surface of the yam was suggested and the research showed a positive effect to the problem. However, another factors including a by-product of chemical residue and searching more feasible material need to be concerned for the future research.