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1

Yarn Damage Evaluation in the Flat Knitting Process

Iqbal Waqar, Jiang Yaming, Qi Ye-xiong, Xu Lei

Autex Research Journal

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2021

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Vol. 21, no. 3

272--283

EN

Textile yarns are subjected to numerous types of forces during knitting, usually leading to yarn damages, such as decrease in tensile, bending, shearing, and surface properties, which are closely related to different yarn properties, knitted structures/actions, and machine settings. This article comprehensively evaluated yarn damages in the computerized flat knitting process. Five different commercially available and commonly used yarns including cotton, wool, polyester, acrylic, and viscose were selected as raw materials, and the tensile, bending, shear, and frictional properties were investigated and compared before knitting and after being unraveled from plain- and rib-knitted fabrics, respectively. The results show that knitting actions/structures exhibit different damage extents for all different raw materials. It has been observed that the modulus is declined by 3–30% for bending, 2–10% for tensile, and 8–80% for shearing due to flat knitting action, respectively. The frictional coefficient of yarns also increased from 6 to 23%. As compared to yarn before knitting, the yarns unroved from plain and rib structures have been damaged to a great extent as a result of the loss of mechanical properties. The results are completely in agreement with the statistical analysis that clearly represents the significant loss in yarn properties during the knitting process. The microscopic analysis of the yarns clearly illustrates the effect of knitting action on yarn surface and mechanical properties. For yarn’s cross-sectional shearing properties testing, this article self-designed an innovative “Yarn Shear Testing Device.” The methodology and results are of great importance for improving the quality of knitted products, evaluating knitting yarns’ knittability, and in the development of high-performance technical textiles.

2

Analysing the Effect of Decatising on the Frictional Properties of Wool Fabrics

Eryuruk S. H., Kalaoğlu F., Bahadir S K, Jevšnik S.

Fibres & Textiles in Eastern Europe

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2014

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Vol. 22, no. 3 (105)

79--83

EN

The properties of wool fabrics desired can only be achieved if appropriate finishing processes are carried out. Decatising is a part of wool finishing processes increasing the fabric surface properties of fabrics. In this study, high pressure decatising process was applied to semi-decatised woven wool fabrics. Surface properties (coefficient of friction, mean deviation in the frictional force, geometric roughness) of the fabrics were measured by KESFB4, and the friction coefficient of the fabrics by means of a Frictorq test machine before and after application of the high pressure decatising process. The effect of high pressure decatising on the fabric surface properties of wool and wool blend fabrics was analysed. It was concluded that high pressure decatising process had a healing effect on the fabric surface properties, and also the coefficient of friction and surface roughness values decreased.

PL

Pożądane właściwości tkanin wełnianych mogą być osiągnięte tylko przy zastosowaniu odpowiednich procesów wykańczających. Dekatyzacja jest jednym z procesów wykańczających tkaniny wełniane polepszającym właściwości powierzchniowe. W przedstawionej pracy stosowano dekatyzację wysokociśnieniową jako uzupełnienie wstępnej dekatyzacji. Badano właściwości powierzchniowe (współczynnik tarcia, średni rozrzut sił tarcia i szorstkość powierzchni) za pomocą przyrządu KES-FB4 oraz współczynnik tarcia za pomocą przyrządu Frictorq przed i po zastosowaniu wysokociśnieniowej dekatyzacji. Analizowano wpływ wysokociśnieniowej dekatyzacji na właściwości powierzchniowe przędz wełnianych i mieszankowych. Stwierdzono, że dekatyzacja miała korzystny wpływ na właściwości powierzchniowe i stwierdzono zmniejszenie współczynnika tarcia.

3

Frictional Coefficient Change of Groove Surface in Compact Spinning with a Suction Groove

Ma H. C., Lu S., Cheng L. D., Hua Z.

Fibres & Textiles in Eastern Europe

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2013

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Vol. 21, no. 5 (101)

40--42

EN

Compared with conventional ring spinning, compact spinning with a suction groove can reduce hairiness and improve yarn quality, and it has certain advantages to long staple fibre. In this article, we analyse the changing rule of rotational speed and study the change curve of the frictional coefficient in the gathering zone. The results show that the fibre bundles’ rotational speed at each point along the surrounding arc gradually decreases from the maximum to zero in the gathering area, but the rotating speed of the fibre bundles is constant in the suction hole. The angle between the parallel component speed and that at each point is near to a linear change in the no suction hole, with there being no change in the suction hole. The parallel component of the frictional coefficient for each point is a variable in the no suction hole, being constant in the suction hole.

PL

Porównując konwencjonalne przędzenie obrączkowe i przędzenie kompaktowe z zastosowaniem rowka ssącego można stwierdzić, że uzyskuje się polepszenie włochatości przy stosowaniu przędzenia z rowkiem. Analizowano charakterystykę zmiany prędkości i krzywe współczynnika tarcia w strefie zbiorczej. Stwierdzono, że prędkość wirowania wiązek włókien zmniejsza się w każdym punkcie łuku toru przędzy, ale prędkość wirowania wiązek włókien jest stała w rowku ssącym. W artykule poddano szczegółowej analizie prędkości i zachowanie przędzy w poszczególnych punktach toru przędzenia.

4

Tool technology to reduce cutting heat generation and its influences

Soe Y. H., Tanabe I., Iyama T., Hoang T. B.

Journal of Machine Engineering

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2010

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Vol. 10, No. 3

5--16

EN

Recently, the use of hard materials has increased for product quality and safety reasons. Consequently, the cutting conditions for these materials become severe resulting in shorter tool life due to higher cutting temperature. In this paper, tool technology to reduce heat generation and its influences during cutting is investigated and evaluated experimentally. The approach for reducing cutting heat generation is considered by changing the tool geometry and reducing the frictiona coefficient between tool and chip. The approach for reducing influence of the generated heat is application of a therma insulator (coating) on the tool material having high thermal conductivity and heat-resistance. The turning process is used in the experiments. The thermal influences are made clear by each experimental parameter and then, the optimum tool parameters were considered from experimental results. It is concluded that; (1) When rake angle was 15 degree, temperature rise on the tool was smallest. (2) Temperature rise on the tools coated with TiAlN or DLC (Diamond Like Carbon) were reduced from 20 % to 30 %. (3) Several tool materials were quantitatively evaluated by consideration of the thermal conductivity, as well as thermal dependency of their hardness.