Yarn Drawing Research Articles

High Efficiency Covering Technology for Covered Yarn Production: Controlling the Spandex Yarn Draw Ratio

This paper proposes a new covered yarn system in which the tension of spandex elastic yarn drawing is controlled. By analysing the relationship between the draw ratio and yarn tension, it was verified that the new tension controlled drawing system is feasible and results in yarns of superior quality and process stability.

The Impact of Machine and Construction Settings on Sliver and Yarn Quality in Ring Spinning Process

Ring spinning is the most important spinning system with its wide application area, high yarn quality and widespread usage in staple fiber spinning. Each parameter in the long process steps in the ring spinning system significantly influences the yarn quality. Within the scope of this study, the effects of the machine and construction settings on the sliver and yarn properties in each of the blowroom, carding, drawing, combing, roving and spinning processes are examined. In this context, the effect of many parameters such as carding parameters, sleeve type and size, combing type, yarn drawing and twisting settings on the quality characteristics of slivers and yarns have been observed. The effects of setting changes were investigated by examining the whole production process of cotton ring yarns with different yarn count and twisting properties. Breaking strength and elongation at break properties and hairiness, unevenness and imperfections of the materials were analyzed. The actual yarn manufacturing in the ring spinning mill was examined and the relations between production and quality were determined. It is thought that the results obtained will be useful for field studies and scientific researches related to ring yarn spinning

Stress transfer of single yarn drawing in soft fabric studied by micro Raman spectroscopy

The load transfer behavior of the Kevlar 49 soft fabric commonly used for bulletproof clothing in yarn drawing test was investigated by micro-Raman spectroscopy. The linear relationship between Raman shift and axial stress of single yarn was established. The axial stresses of warp yarn in soft fabric with and without preload condition were obtained by Raman measurement under tension, and they conform to the theoretical prediction using a yarn-drawing model with interface debonding. The experimental results show that the drawing load is transferred along the yarn from the beginning to the end. In the process of straightening the yarn, the interfacial friction shear stress caused by the yarn relative sliding remains almost constant, and the length of straightened yarn becomes longer as the external load increases. The preload plays a role in inhibiting the straightening of the yarn, which is helpful for the load transfer in the sliding friction section.

Structural Transitions During Orientational Drawing of Yarns. Review

Known data are generalized on the structural transitions and orientational strengthening of yarns made from different polymers, from the standpoint of the current state of the art. Their characteristic features as well as the similarities and differences for processes forming the structural and mechanical properties are demonstrated. Consideration of the process of orientational drawing of PET is emphasized, letting us show the characteristic features of structural transitions from the amorphous to the crystalline state. Material in this paper has combined basic scientific data on problems of orientational strengthening, which is quite important in the current stage of development of polymer technology for designing new processes.

Design, Manufacturing of A New Laboratory Type Filament Yarn Drawing Machine And Featured Yarn Development Studies

In the establishments where continuous filament yarn production is made, the production line covers a fairly large scale, the production continues non-stop all day long and this industrial type machines possess a large number of process parameters. Because of these reasons, during the production activities it is pretty demanding to R&D and P&D studies in industry. In the view of this disadvantageous case, this study was carried out and with this study it was aimed to do continuous and systematic researches towards filament yarns. Thus, this study has two stages. The first one is the study of design, improving and manufacturing a lab-type filament yarn production machinery based on melt spinning principle and the second one is the study of original product development done in the manufactured machinery. As a result, many scientific studies about production of filament yarns especially for application of technical textiles can be realized with this lab-type machine.

Multi-Million Fully Atomistic Molecular Dynamics Simulations of Yarn Formation from Carbon Nanotube Forests

ABSTRACTIn this work we present preliminary results from multi-million fully atomistic classical molecular dynamics simulations carried out to test different existing mechanisms that have been proposed in the literature to explain the drawing of yarns from carbon nanotube forests. Despite the fact that it has been almost ten years since yarns were first drawn, there are still controversies on the mechanisms and necessary conditions that can produce yarns and sheets drawn from carbon nanotube forests. Moreover, few works have tried to understand at atomistic level the details of yarn drawing mechanisms, and no fully atomistic simulations have been carried out so far on this particular subject. Our preliminary results suggest that only direct van der Waals interactions among large bundles seem not to be enough to explain the yarn drawing process. Bundle interconnectors (such as small bundles connecting large bundles) were observed to play a critical role in our simulations. Depending on the topology of these interconnectors it was possible to observe from the simulations fibers/yarn formation from proposed structural models. These models were built based on structural information inferred from scanning electron microscopy data.

In-situ study of the carbon nanotube yarn drawing process

Recognizing the main factors affecting the spinning of carbon nanotube (CNT) yarns from vertically aligned brush-like CNTs (BCNTs) persists as a difficult challenge. Here, using in-situ drawing of as few as 20 CNTs from as-grown BCNT and measuring the force required for their separation from BCNT, we demonstrate that samples with different spinnability levels exhibit different separation force behaviors. Moreover, the average separation force per CNT differs among samples. Results show that the separation force in spinnable samples depends on the drawing location: it can be as high as 15 nN/CNT at the top of a sample and as low as 3 nN/CNT in the middle of a sample. In contrast, this force is around 10 nN/CNT for un-spinnable samples and is nearly constant throughout such samples. Detailed drawing site observations can pave the way to elucidation of the mechanisms of dry drawing processes of BCNT, which are vital for enhancing the strength of carbon nanotube yarns.

소모연신사의 연신비가 니트의 역학적 성질에 미치는 영향

This paper surveys the effects of drawing conditions of the worsted staple yarns on the mechanical properties of the knitted fabrics for highly aesthetical fabrics. The drawn worsted yarns were made on the yarn drawing system with various draw ratios under the fixed conditions of setting time, reduction and oxidation. The knitted fabric specimens were prepared on the 16 gauge circular knitting machine using these drawn worsted staple yarns. The tensile, shear, bending, compression and surface properties of these knitted fabrics were measured by KES-FB-AUTO-A system and also discussed with the drawing conditions. The tensile linearity, shear stiffness and bending rigidity decreased with increasing draw ratio. Any changes were not shown on the compressional properties with drawing conditions. But the friction coefficient of the knitted fabric on the course direction increased with increasing draw ratio, while there was no change according to the draw ratio on the wale direction.

연신공정 조건이 소모연신사의 물성에 미치는 영향 (II)

This effects of drawing conditions on the physical properties of the drawn worsted yarns were investigated. The drawn worsted yarns were made on the yarn drawing system with various drawing conditions such as concentration of reducing agent, draw ratio, setting time of drawn yarn and concentration of oxidizing agent. The dry and wet shrinkage, irregularity(CV%), thin and thick part, hairiness and abrasion resistance of these various specimens were measured and discussed in terms of various drawing conditions.

연신공정 조건이 소모연신사의 물성에 미치는 영향 (I)

This effects of drawing conditions on the physical properties of the drawn worsted yarns were investigated. The drawn worsted yarns were made on the yarn drawing system with various drawing conditions such as concentration of reducing agent, draw ratio, setting time of drawn yarn and concentration of oxidizing agent. The dry and wet shrinkage, irregularity(CV%), thin and thick part, hairiness and abrasion resistance of these various specimens were measured and discussed in terms of various drawing conditions.

A new amorphous heat‐resistant aromatic polymide fiber prepared by wet‐spinning

AbstractA new amorphous heat‐resistant aromatic polyamide was prepared by solution polymer‐ization in N‐methylpyrrolidone, (NMP) from equimolar amounts of 4,4′‐methylenedianiline, p‐phenylenediamine, isophthaloyl chloride, and terephthaloyl chloride. After neutralization of the byproduct HCl, with calcium hydroxide, the as‐polymerized polymer solution (15.7% polyamide in NMP) was spun directly on a horizontal wet‐spinning device. Yarn drawing of as‐spun fibers, near the glass transition temperature of the polymer, was performed on a hot‐drawing equipment. To determine the optimal drawing conditions, the influence of the draw ratio on the tensile properties was studied in detail. On the basis of these results, a draw ratio of 1.7 was applied to prepare a larger quantity of drawn polyamide multifilament yarn (f330 and f500). Tensile properties of both fibers and filaments were determined by standard methods. The fibers are characterized by an excellent thermal stability as indicated by temperature‐dependent tensile measurements, long‐term heat resistance, boiling‐water shrinkage, hot‐air shrinkage, etc., of the fibers. Despite the amorphous character of the polyamide fiber, it offers an excellent resistance to common organic solvents (except to THF and DMF). Moreover, the fiber exhibits a good resistance toward diluted inorganic acids, salts, and bases. Depending on the specific properties of the polyamide fiber, the material may find applications in, e. g., hot‐air filter fabrics, protective clothing, electrical insulation paper, or advanced structural materials. © 1993 John Wiley & Sons, Inc.