International Journal of Textile and Fashion Technology (IJTFT) ISSN 2250-2378 Vol. 3, Issue 4, Oct 2013, 15-22 © TJPRC Pvt. Ltd.
QUALITY OF NEW KIND OF YARNS VERSUS RING SPUN YARNS – COMPARATIVE STUDY GABRIELA KRUPINCOVA Department of Textile Technology, Faculty of Textile Engineering, Technical University of Liberec, Studentská, Liberec, Czech Republic
ABSTRACT Ring spun yarn is still considered by most of producers as yarn with ideal structure and parameters. This preference is confirmed by end-textile-product manufactures because of overall balance of quality aspects, which still make them the yarns of choice for most applications. Development in yarn manufacturing is continuing and it is a challenge for most of scientific teams. The new spinning system was developed and its potential can be interesting from the pint of view of yarn quality and also economical cost. Main aim of this article is to show a part of results of verification tests, which was realized on cotton samples. The influence of spindle speed on selected yarn characteristics is discussed and statistically verified. The outputs of experiments indicate that the quality of the “New yarns” is comparable with conventionally produced ring yarn with lover economical cost.
KEYWORDS: ANOVA, New Spinning System, Spindle Speed, Quality of Yarn INTRODUCTION Yarns produced by classical ring spinning technology still constitute an important part of world production. Principle of ring spinning technology has been developed in the 19th century. Since that time, the principle of ring spinning system is not changed, only technologically and technically improved as remarked e.g. Klein W. (1987) and Lord P. L. (2003). The classical conventional ring spinning technology allows processing of a wide range of fiber materials and ring spun yarns are suitable for a wide segment of products. Due to strong competition in the market starting in 80s of 20s century, it was necessary to reduce the economic costs of yarns production. A number of scientific institutions upgraded conventional spinning system or developed new unconventional methods of yarns production such as rotor, friction, air jet or other spinning systems. Conventional and unconventional spinning systems are generally described e.g. by Chaudhuri A. (2003), Klein W. (1987) and Lord P. L. (2003). There were published numerous design solutions and patents, but only some of them were put into practice. On the other hand the unconventional technologies enabled an increase in yarn production, but always with some restrictions (limited range of processed fibers, different quality of yarn suitable only for a narrower segment of products, etc.). Current and future trends in yarn production, spinning capacity and economic aspects for various technologies discussed Oxenham (2002). A challenge of scientific team solved the project Textile Research Centre II was to find a way of yarn production which would enable spinning of yarn qualitatively similar with ring yarn at lower economic costs. The new solution is based on a similar principle without traveler. The new system is carried out on an operating unit which comprises a driven spindle and a balloon control ring which is concentric with the spindle, is driven in the same sense as the latter and has an inner operating surface. In order to achieve a high operating speed, the centrifuging process always first imparts the shape of a rotating open loop to the yarn which is entrained by the operating surface and runs in the direction towards the tube on the spindle. The yarn is then drawn off from the open loop and wound directly onto the tube. At the same time, this rotating
open loop can be radially delimited by a rotating or stationary delimiting ring. This principle is relatively new and the details can be found in patent WO 1997032065A1. Verification tests were realized by various machine settings. Various fiber materials were processed and various technological yarn parameters were used. Main aims were to find limitations of a new spinning system and compare quality of new yarns with the conventional ring spun yarns. Krupincová, G. (2012) shows a part of all verification tests. The influence of spindle speed on quality of experimentally spun yarns will be discussed in this article. The effect of spindle speed was studied by many authors for various materials and yarn technological parameters. The range of spindle speed in earlier experiments was selected in respect to spun yarns from the pint of view of yarn count, yarn twist and technological possibilities of spinning frames. For example, Choudhuri A. (2003) summarize the results about the influence of spindle speed on yarn quality of various authors for 100% cotton, 100% polyester, 100% acrylic yarn and blended yarn spun from polyester and acrylic and study the influence of wide range of spindle speed for relatively fine yarns with nominal count 18tex and 19tex. Lawal et al (2001) observe the effect of spindle speed on coarse blended flax and cotton yarn of 39tex and 59tex. Iftikhar et al. (2002) study the 100% cotton yarns of 33tex for four levels of spindle speed with various twist coefficients. The set of qualitative parameters in terms of yarn technological parameters (yarn count, yarn twist), yarn unevenness, yarn hairiness, number of faults and mechanical parameters (relative strength, elongation, work, modulus) was usually measured and evaluated for one component or for blended yarns. It was confirmed that the increase of spindle speed leads to smaller or higher changes in yarn quality. Most of scientists found out, that spindle speed causes increase of yarn unevenness, number of faults, hairiness and relative strength and also to decrease of yarn elongation. They also noted that there were the problems with compliance between nominal and real yarn technological parameters (yarn count, yarn twits) and increase of end breakage during yarn production.
MATERIALS AND METHODS Experimental Materials Main aim of this experiment was to verify the production limits of new technology mainly in spindle speed and to compare quality of “New yarn” N with classical ring yarns R. The experiment was realized on set of 18 yarns produced under comparable conditions from 100% cotton fibers. N yarns were produced in three levels of nominal yarn count in given level of Phrix twist coefficients and five-steps of spindle speed to actual limit of the prototype spinning system. To achieve a constant rate of twist coefficient was always with the increase of spindle speed constant speed ratio and towing speed. R yarns made from the same material in the same nominal yarn count and level of Phrix twist coefficients were used as comparative yarns. Spindle speed and towing speed in case of R yarn, were in line with the normal type of ring spinning machines. Details of yarn production (spindle speed o, towing speed v, draft P) and yarn technological parameters (yarn count Tn, Phrix twist coefficients a, yarn count T, yarn twist Z) are shown in Table 1. Yarns 7.4tex and 12tex were spun from combed cotton MII 4.4mic and yarns 29.5tex were spun from carded cotton AI 4.39mic. Table 1a: Yarn Samples – Tn = 7,4tex, a = 48ktex2/3m-1, P = 32,4 Yarn Type o [min-1] v [mmin-1] T [tex] Z
N 44000 35,2 7,33 (7,26; 7,39) 1317 (1303; 1332)
N 46000 36,8 7,20 (7,10; 7,29) 1288 (1270; 1306)
N 48000 38,4 7,34 (7,31; 7,37) 1293 (1275; 1310)
N 50000 40 7,21 (7,15; 7,26) 1319 (1302; 1336)
N R 52000 12550 41,6 10 7,33 7,29 (7,29; 7,37) (7,28; 7,31) 1292 1368 (1275; 1310) (1345; 1390 )
Quality of New Kind of Yarns versus Ring Spun Yarns – Comparative Study
Table 1b: Yarn Samples – Tn = 12tex, a = 49ktex2/3m-1, P = 33,3 Yarn Type o [Min-1] v [Mmin-1] T [Tex] Z [M-1]
N N N N N R 40000 42000 44000 46000 48000 12550 42,7 44,9 47,1 49,2 51,4 13,4 12,11 12,26 12,18 12,10 12,07 12,20 (11,99; 12,23) (12,23; 12,29) (12,09; 12,28) (12,03; 12,16) (11,94; 12,19) (12,04; 12,36) 1094 1076 1048 1027 1035 1039 (1079; 1109) (1064; 1087) (1032; 1063) (1010; 1044) (1023; 1046) (1014; 1064) Table 1c: Yarn Samples – Tn = 29,5tex, a = 67ktex2/3m-1, P = 23,7
Yarn Type o [min-1] v [mmin-1] T [tex] Z [m-1]
N N N N N R 34000 36000 38000 40000 42000 13450 47,9 50,7 53,5 56,3 59,2 18,9 29,92 29,87 29,52 29,57 29,42 29,37 (29,65; 30,20) (29,70; 30,03) (29,52; 29,74) (29,26; 29,89) (29,19; 29,64) (29,37; 29,50) 762 753 749 734 744 751 (754; 770) (744; 761) (741; 757) (762; 742) (737; 751) (743; 760)
Testing Methods Yarn analysis included the verification of technological parameters (yarn count and yarn twist) together with the analysis of yarn unevenness, yarn hairiness, number of faults and yarn mechanical parameters. The analysis of yarn crosssections was applied to obtain also the information about the internal structure of yarn. The specific methodology was used and therefore is briefly described below. Compliance of nominal yarn count Tn and experimental yarn count T (testing length 1000m, repeating 10) and Phrix twist coefficient and yarn twist Z (testing length 500mm, pretension selected in respect to yarn count, repeating 50) is verified according to international standards. The analysis of yarn unevenness CV, number of faults (Thin-40%, Thin-50%, Thick+35%, Thick+50%, Neps +200%, Neps +280%), cumulative hairiness index H and its standard deviation sh is evaluated on 1 km yarn length by the speed 400 mmin-1 5 times by Uster Tester 4. The internal structure of compared yarns was evaluated by specific internal standard, which is based on preparation of yarn cross-section and their analysis. Yarn cross-sections are prepared by special methodology described in IN 46-108-01/01. Their evaluation was realized in respect to IN 22-103-01/01. Křemenáková D. et al. (2004) describe all details of testing principals. Image Analysis – Nis Elements enables to scan image of yarn cross-section. The coordinates of the centre of gravity of all fibers are detected interactively. Yarn axis is determined as a median of these coordinates. Equivalent diameter of fiber de is estimated thanks to parameters of fibers - fiber fineness t and fiber mass density as follows:
de 4T /
Individual fiber cross-sections are reconstructed. At first it is consider ideal fibers with circular cross-section parallel to yarn axis. Than the area of fibers cross-section form is adapted regarding to the yarn twist and to the distance between yarn axis and fiber centre of gravity. The next step is applying the set of radial rings with yarn axis in the centre and with the constant width h (0,01mm). The ratio between the total fiber area in radial rings Sk and the area of individual radial rings Sck represents the packing density in k-th radial ring in i-th yarn cross-section mk. The dependence of radial packing density mk on yarn radius r can be represented by a histogram. Effective yarn diameter Def corresponds to the value of radial packing density at level 0, 15. This can be estimated for example by interpolation from the measured values of
packing density mk. Effective packing density mef is the ratio between the effective fiber area Sef and the area of the circle Scef of effective diameter Def as follows:
mef = Sef Scef
The statistical characteristics (mean value, standard deviation, variation coefficient and confidence interval) of fiber number in the yarn cross-section n, yarn diameter Def, effective packing density mef from the values of the individual images of yarn cross-section (typically 50 for one sample of yarn) is estimated. The mechanical parameters like the relative yarn strength F and yarn elongation e are measured by Instron tester under standard conditions (testing length 500 mm, pretension 0, 0825 mNtex-1, testing time 20s Âą 3s, repeating 50).
RESULTS AND DISCUSSIONS The obtained experimental data was statistically processed. Homogeneity, normality and independence were verified. The typical statistical parameters were calculated (mean, standard deviation, variation coefficient, confidence intervals). The influence of spinning system and spindle speed was assessed. n 1 ,6 e
1 ,4 1 ,2 1
0 ,8 0 ,6 0 ,4 H
Neps +2 80 %
T hin -4 0%
Nep s +2 00 %
T h in -50 %
T hick +5 0% 7, 4tex N2
T hick +35 %
7,4 tex N3
7 ,4 tex N4
7 ,4tex N5
7, 4 tex R
Figure 1a: Comparison of Yarn Properties - 7,4tex n 3,5 e
2 1,5 1 0,5
Nep s +28 0%
T hin -4 0%
Nep s +2 00 %
T hin -5 0% T hick +5 0%
12 tex N1
1 2tex N2
T h ick +3 5% 1 2tex N3
12 tex N4
12 tex N5
1 2tex R
Figure 1b: Comparison of Yarn Properties - 12tex
Quality of New Kind of Yarns versus Ring Spun Yarns â€“ Comparative Study
n 2,5 e
Def 2 1,5
1 0,5 H
Nep s +28 0%
T hin -4 0%
Nep s +2 00 %
T hin -5 0% T hick +5 0%
29 ,5 t ex N1 29 ,5 t ex N5
29 ,5 t ex N2 29 ,5 t ex R
T h ick +3 5% 29 ,5tex N3
29 ,5tex N4
Figure 1c: Comparison of Yarn Properties - 29,5tex Figures 1a, b, c are basic comparison of N and R yarn, where the R yarn is comparable standard. It means in other words, that level of each characteristics of N yarn is compared with level of the same characteristics of R yarn. Yarns 7,4tex N have in comparison with R yarn similar n, slightly less Def, slightly high mef, nearly same CV, less number of Thin-40%, Thin-50%, Thick+35%, and Thick+50%, higher number of Neps +200%, Neps +280%, H, less F and e. Only one yarn N3 shows higher F than R yarn. In case of yarns 12tex, it is evident that n, Def, mef are for N yarns and R yarn very similar, number of Thin-40%, Thick+35%, Thick+50%, Neps +200% and Neps +280% are distinctly higher, H is also higher, F and e are nearly similar. Small difference between 29,5tex N yarns and R yarn is clearly seen in n, Def, mef, H and F. The quality of 29,5tex N yarns is better than R yarn in terms of number of Thin-50%, Neps +200% and Neps +280% and it is worse than R yarn in terms of number of faults mainly Thin-40%, Thick+35%, Thick+50%. It is obvious that n, Def, mef should be similar because of same nominal technological parameters Tn and a. The differences between CV, H, F and e of N and R yarns are not so great, only number of faults of N and R yarn differs markedly. The variability of number of faults is usually high and therefore also the appropriate confidence interval is wide. On the other hand the most of differences are hidden in confidence bound.
Figure 2: Yarn Unevenness
Figure 4: Yarn Strength
Figure 3: Yarn Hairiness
Figure 5: Yarn Elongation
Figures 2 to 5 show dependence of evaluated yarn parameters (CV, H, F and e) on spindle speed for N and R yarns. The quality of N yarns and R yarn seems to be comparable. From the point of view of spindle speed influence, it can be concluded: Yarn unevenness of N yarns increases slowly when spindle speed increases mainly for yarn of 29,5tex yarn count. Increase given by using higher spindle speed is visible also in case of yarn hairiness index mainly for yarn of 29,5tex yarn count. There is no affect given by change of spindle speed on relative yarn strength of N yarn. Only one N yarn produced by o=38000min-1 shows considerably higher relative yarn strength that other N yarns. In contrast, elongation of N yarns with increasing of spindle speed decreases. Trends are visible, but in all cases except previously mentioned yarns and N3 (relative strength F) the confidence intervals of evaluated characteristics are overlapped. The influence of yarn type and spindle speed on selected characteristics of N and R yarns was verified by ANOVA analysis together with Scheffe’s pair-wise comparisons. The hypothesis about equality of means among different factor levels is tested in two steps. Firstly the influence of spindle speed (factor 1) was verified and than the comparison of N and R yarns was realized (factor 2). The theoretical value appropriate for factor 1 is 3, 48 and for factor 2 is 4, 49. The calculated critical value and relevant p-value for all yarn characteristics are for both factors shown in Table 2. ANOVA analysis verified that the influence of spindle speed on all characteristics of N yarns is not statistically significant. It can be also concluded, that the quality of N yarns is statistically comparable with appropriate R yarn standard. Scheffe’s pair-wise comparisons confirmed these results in all cases. Table 2: Results of ANOVA Analysis Characteristics / Calculated Critical Value p-Value Factor 1/ Statistical Results Factor 1/ Factor 2 Factor 2 CV [-] 0,087 / 2,732 0,985 / 0,118 Thin-40% [km-1] 0,107 / 0,033 0,977 / 0,893 Thin-50% [km-1] 0,058 / 0,080 0,993 / 0,780 Thick+35% [km-1] 0,060 / 6,874 0,992 / 0,018 Thick+50% [km-1] 0,010 / 2,251 0,999 / 0,153 Neps +200% [km-1] 0,022 / 1,448 0,999 / 0,246 Neps +280%) [km-1] 0,133 / 0,160 0,967 / 0,694 H [-] 0,038 / 0,485 0,997 / 0,496 F [Ntex-1] 0,625 / 0,165 0,655 / 0,690 e [%] 0,060 / 0,466 0,992 / 0,504
CONCLUSIONS A part of verification tests on prototype spinning system was presented in this article. The influence of spindle speed was evaluated. The quality of “New yarns” was compared whit conventional ring spun yarns. Usually in case of R yarn, spindle speed causes increase of yarn unevenness, number of faults, hairiness and relative strength and also to decrease of yarn elongation. The trends of presented experimental data of N yarns are in a good accordance with privies outputs of other scientists. The statistical analysis confirmed that the influence of spindle speed is not significant. ANOVA analysis and Scheffe’s pair-wise comparisons verified that the quality of N and R yarn are comparable in all analyzed characteristics. The new system of yarn production has a big potential because of economical benefits in comparison with the conventional ring spinning technology. More pronounced savings were reported in case of very fine and worse yarns at level of 22% of total cost. Smaller reduction of economical const was detected in middle range of yarn count and the savings were only on level 10% of total cost.
Quality of New Kind of Yarns versus Ring Spun Yarns – Comparative Study
ACKNOWLEDGEMENTS This work was supported by Czech Ministry of Education - the research project No 1M0553, Textile Research Centre II.
Chaudhuri A. (2003) Effect of Spindle Speed on the Properties of Ring Spun Acrylic Yarn. IE (I) Journal, 84 (4), pp. 10 - 13.
Iftikhar A., Nisar A. J. And Nadeem H. (2002) Influence of some mechanical Factors of Ring Spinning Machine on Cotton Yarn Quality. Pakistan Journal of Applied Sciences, 2 (4), pp. 453 – 456.
Klein W. (1987) A Practical Guide to Ring Spinning. Textile Progress, 4. The Textile Institute.
Křemenáková D. et al. (2004) Internal Standards. Textile Research Centre Textile, Faculty of Textile Engineering, Technical University of Liberec.
Krupincová G. (2012) Yarn Hairiness. Doctoral dissertation. Faculty of Textile Engineering, Technical University of Liberec. (only in czech)
Lawal A. S., Nkeonye P. O. and Anandjiwala R. D. (2011) Influence of Spindle Speed on Yarn Quality of Flax/Cotton Blend. The Open Textile Journal, 4, pp. 7 - 12.
Lord P. L. (2003) Handbook of Yarn Production: Technology, Science and Economics. Woodhead Publishing.
Oxenham W. (2002) Current and Furute Trends in Yarn Production. Journal of Textile and Apparel, Technology and Management. 2 (2).
Patent WO 1997032065A1 Spindle spinning or spindle twisting method and operating unit for carrying out this method.
Ring spun yarn is still considered by most of producers as yarn with ideal structure and parameters. This preference is confirmed by end-tex...