Optimizing Carding Speed Parameters and C-60 RSB Draft to Improve Sliver Quality

ABSTRACT

The optimization of settings of spinning machinery is one of the technically most urgent tasks when it comes to achieving the best possible raw material utilization for a high-quality yarn. Carding, as part of an integrated draw frame, is the very critical process in spinning preparation for open end rotor spun yarn manufacturing. The aim of the integrated draw frame process in a spinning line is to produce uniform slivers (with low deviation in mass per unit length) where the fibers are laid parallel and the sliver has relatively low neps, short fiber, trash and dust contents. This work examined the potential effects of a range of speed settings on the physical properties of sliver. Optimization results of the study showed that 3.5 CVm% and 2.8 U% of sliver achieved with 96.3% desirability with optimum predicted value of neps 252 cnt/g, short fiber content by number 25.8%, trash 29 cnt/g and dust 234 cnt/g satisfied at licker in speed of 1250 rpm, cylinder speed of 650 rpm, flat speed 0.29 m/min, and C 60 RSB total draft of 2.11 for processing the cotton variety of Deltapine 90 (DP-90).

摘要

优化纺纱机械的设置是实现高质量纱线的最佳原材料利用率的技术上最紧迫的任务之一. 梳棉作为整体牵伸机构的一部分，是开口转杯纱生产中纺纱准备的关键工序. 纺纱线上的整体并条机工艺的目的是生产均匀的条子（单位长度质量偏差小），其中纤维平行排列，条子的棉结、短纤维、杂质和灰尘含量相对较低. 这项工作考察了一系列速度设置对棉条物理性能的潜在影响. 优化研究结果表明，在转速为1250rpm、滚筒转速为650rpm、平速为0.29 m/min、C60RSB总牵伸为2.11的条件下，棉结252 cnt/g、短纤含量为25.8%、杂质29 cnt/g和粉尘234 cnt/g的最佳预测值，对德尔塔平90棉品种（DP-90）的加工效果分别达到3.5CVm%和2.8 U%，切条率达到96.3%.

KEYWORDS:

• Deltapine 90
• IDF sliver
• carding speed
• optimization
• RSB draft
• box-behnken design

关键词:

• Deltapine 90
• IDF条子
• 梳理速度
• 优化
• RSB草案
• 箱线图

Introduction

The aim of carding process in spinning line is to produce uniform fiber slivers (with low deviation in mass per unit length) where the fibers are laid parallel and the sliver has relatively low neps. In order to achieve higher fiber performance, there should be minimal fiber damage in the carding process i.e. the usable fiber length should be unaffected. While processing natural fibers, the trash content and dust removal also play a very significant role with regard to the yarn quality.

The production of more uniform yarn needs meaningful and reliable measurements of significant fiber properties now at the forefront of concerns for spinners, namely, short fiber content (SFC) which is important property of cotton (Tesema and Drieling 2019; Zeidman, Batra, and Sasser 1991) and neps (Davidonis, Landivar, and Fernandez 2003; van der Sluijs and Hunter 2017).

The second worldwide Bremen survey presented by the Fibre Institute of Bremen e.V. and the Bremen Cotton Exchange in 2020/21 reported that SFC was the top response of spinners for improvements needed in cotton quality demands to produce high-quality yarn (Drieling and Hagedorn 2021).

The machine operator on a card neither has the possibility to check the carding performance with regard to fiber damage, nor does he have the possibility to change the process parameters or even the stationary carding elements. Especially during the processing very small or crucial batches, which are accompanied by high raw material costs, there exists no possibility to verify the fiber length of the carded fibers using an offline process the process which most of the spinning mills are implemented. A lot of detailed research has been carried out in the field of interaction between the machine, the process and also the quality parameters. But these research works are carried out on the conventional card and draw frame machines. Nevertheless, the present research work is carried out using the modern integrated draw frame carding machine on Reiter Card C 60 with RSB modules (module (coiler) drafting system and autoleveller). This research work primarily designed to optimize the Licker-in speed (rpm), card cylinder speed (rpm), flat speed (m/min) and RSB draft so that to produce a quality carded sliver for rotor spun yarns. Optimizing raw material utilization and machine parameters, while at the same time increasing quality and productivity of yarn manufacturing, represents the top challenge for spinning mills that are participating in the global competition.

Optimizing the machine parameters has also a significant role to control the quality and productivity of intermediate and final products by correcting any deviation that can be identified quickly and allowing the swift implementation of process control steps designed to counteract the quality problem.

Up to the early decades, almost all yarns made from staple fibers were produced on the ring-spinning system, but this versatile process now appears to have reached its practical limits with regard to productivity and quality. Hence, research has been carried out in the last few decades with a view to developing newer methods that could offer higher productivity in all count ranges. Several new ideas have been put forward, and today the rotor spinning system has shown promise as offering alternatives to the conventional ring spinning system in the coarse count range. The rotor spinning system has already established its potential, and today it accounts for more than 30% by weight of the staple fiber yarns produced in the world. Environmental protection and wastes recycling have become also the most important tasks for the current sustainable development goal of the United Nations. Textile industry, in particular, cotton spinning, confronts this kind of problems. In spite of the technical evolution for different Blowroom machines, generated wastes contain a great rate of fiber (Leifeld 1996; Specklin 1994). On the other hand, raw material cost, prices, energy and labor costs are rising since the crises of Ukraine war. Therefore, the spinner is forced to improve exploitation of the raw material. The first solution is to provide a high cleaning efficiency during the Blowroom and Cards. The second solution is in recovery of fibers from wastes (Leifeld 1996).

Now a days, rotor spinning is becoming the most widely used technology because of its features, including it requires fewer laborers, lower maintenance costs, fewer spare parts, less floor space, and less energy consumption and it can process waste raw materials recycled from the machines. Besides, less machinery is involved in the yarn manufacturing process by eliminating the speed frame and cone winding process (Karthik and Murugan 2016).

Furthermore, rotor spinning produces approximately 2.5% less waste than ring spinning for all yarn counts (Arain et al. 2012).

Even though open-end rotor spinning has eliminated several yarn processing stages; however, still carding is very essential process for rotor spinning. The carding process significantly influences the sliver quality and the resulting yarn characteristics. The change in the carding process parameters directly influences the yarn quality and performance in the fabric forming process (Chaudhari, Kolte, and Chaudhari 2017). Therefore, it is essential to determine the optimum carding process parameters integrated with draw frame.

Materials and methods

The materials used in this research work were lint cotton fibers of DP-90 variety brought from northern Ethiopia. From this cotton, sliver was produced using the integrated draw frame machine of model Card C 60-RSB. The count of the sliver produced was 0.11Ne.

The fiber property of the lint cotton was measured using the high volume bundle fibers testing instrument of model USTER^Ⓡ HVI 1000, and card sliver properties were measured using single fiber testing instrument of type USTER^Ⓡ AFIS PRO 2. Martindale MT 5 high precision evenness tester was used to assess the coefficient of variation of mass (CVm %) and unevenness (U %) of carded sliver.

This research work was designed to study the effect of carding machine process parameter and draft settings of drawing module on the 100% cotton carded slivers that was used as an input for rotor spun yarns. As it is mentioned above, the sliver was produced by the integrated drawing machine with a count of 0.11Ne. After testing the quality of input cotton quality parameter, the fiber tufts engaged to pass through the carding and drawing machine by varying machine settings of licker in speed, flat speed, cylinder speed, and RSB draft. The production of sliver was done at Bahir Dar Textile Share Company on Card C 60- RSB drawing machines. Coefficient of variation of mass (CVm %) testing was also carried out in BDTSC spinning laboratory based on standard methods. The lint cotton and sliver samples were conditioned with standard atmospheric conditions for laboratory testing at 20 ± 2°C temperatures, and 65% ± 2 relative humidity for 24 h before testing (Standard 2005).

Cotton samples used for the study were collected from the bales of Bahir Dar Textile Share Company in the bale store according to ASTM D 1441 - 00, a standard for sampling cotton fibers for testing. A representative sample of ten bales was sampled for each lot, and two-lot tests were carried out. Hundred gram of cotton subsamples were taken from each side of the bale (Figure 1). Then, the two subsamples were combined to prepare for instrumental testing. About 2 kg of lint cotton were taken in different polythene bags for testing preparation. The collected samples were conditioned for about 24 h under standard atmospheric conditions at a relative humidity (RH) of 65% ± 2 and a temperature of 20°C ±2°C according to ISO 139 (Standard 2005).

Figure 1. Between bale variability sampling (Gourlot J.-P. And Driling A., 2012, ISBN: 978-2 -87,614-686-0. EAN:9782876146860).

After mixing formulation carried out, the bales of cotton were laid down in the blow room and conditioned for 12 h in an open state. Picking and opening of lint cotton bales was accomplished by an automatic bale opener (i.e., UNfloc 11). The blended material was processed with Reiter blow room machines and then to the integrated draw frame toward the open-end line.

The effect of licker in speed, flat speed, cylinder speed and RSB draft on the quality of the sliver required to open end rotor spun yarn production was studied. From the sliver 20 Ne, open-end rotor spun yarn was produced and its properties studied.

The HVI fiber properties of the mix along with statistical parameters of commercial cotton variety Deltapine (DP-90) are shown in Table 1.

Table 1. Average HVI test results of the LoT 1 and LoT 2 Mix.

	HVI Parameters
	No. of	Mst	Mic	Mat	UHML	UI	SFI,	Str	Elg	TrID,	CGrd	SCI
LOT	Bales	%			mm	%	%	cN/tex	%	Tr-Grd	Upland
LOT 1	51	6.4	4.36	0.87	29.0	81.2	10.2	20.0	5.1	4	31–1	97
LOT 2	67 Average	6.5 6.4	4.0 4.2	0.85 0.86	28.0 28.5	81.0 81.1	10.0 10.1	22.0 21.0	5.5 5.3	3 4	31–1 31.1	98 97.5
	Total No. of Bales used in the mix = 118

Average AFIS results of LOT 1 and LOT 2 and the mean result of the mix is presented in Table 2.

Table 2. Average AFIS test results of the Mix.

	AFIS parameters
	No. of	Neps	SFC (N)	Trash	Dust
LOT	Bales	cnt/g	%	cnt/g	cnt/g
LOT 1	51	182	21.7	110	1175
LOT 2	67	220	26.6	88	576
	Average	201	24.15	99	876

Results and discussion

Optimizing licker-in and cylinder speeds interaction effects

As it was mentioned in the materials and methods section, this research work was designed to study the effect of carding machine process parameter and draft settings of drawing module on the 100% cotton carded slivers that were used as an input for rotor spun yarns.

The incidence of thin and thick places increases with increasing coefficient of variation of mass (CVm %). The good association of thin, thick places with CVm % implies that the factors which influence CVm % are also likely to influence the thick and thin places. Extensive mill studies have also shown that short fiber percentage in the mixing, the type and condition of drafting system, drafting parameters, the quality of carding and combing are the major factors influencing CVm % as well as thin and thick places. In this study, increasing the speed of licker – in from 1250 to 1350 rpm and cylinder speed from 650 to 700 rpm results in increasing the coefficient of variation of mass (CVm %) Figure 2 (right). The produced carded sliver samples were also tested for their uniformity using a Martindale MT-5 evenness tester and its is demonstrated by 3D surface plot Figure 2 (left). The conversion factor CV = 1.25 U (USTER statistics 2007), which can be used for mass variation with normal distribution is also proved by the found result.

Figure 2. Licker-in and cylinder speeds 3D surface plots – Their interaction effects on the U% (left) and CVm% (right).

Similar trend is observed that increasing flat speeds (keeping the cylinder speed at 650 rpm) results in deceasing the CVm % and U % of carded sliver. This is because the increase of flat speed reduces the neps and SFC. Therefore, the degree of parallelization of fibers becomes higher because of better carding action. As a result, the increase of flat speed (keeping the cylinder speed at 650 rpm) reduces the irregularity of carded sliver. Nevertheless, increasing the cylinder speed beyond 650 rpm resulted in the increase of the carded sliver irregularity.

Based on this study, there is a relationship between total draft and CVm % (U %) of RSB draft. Increase in total draft of the C 60 RSB draw frame causes a decrease in CVm % (U %) of the sliver. This is because of that coefficient of relative fiber parallelization at the sliver increases as the total draft increases which minimizes the draft irregularity of the sliver by making it more uniform. But higher draft in the C 60 RSB draw frame (>2.11) was resulted by reduced sliver uniformity (Figure 3).

Figure 3. RSB draft and cylinder speeds 3D surface plots – Their interaction effects on the U% (left) and CVm% (right).

The interaction effect between the Licker-in and main cylinder was presented in Figure 4. As we can see in this figure, increasing the Licker-in speed from 1250 to 1350 leads to the improvement of quality of carded sliver by removing more amount of neps. When the Liker-in speed is increased from 1250 rpm to 1350 rpm, the amount of neps in the sliver was reduced from 260 cnt/g to 231 cnt/g. This improved of the quality of the carded sliver, but at higher Licker – in speed the fiber damage was observed by increasing more amount of SFCs. This is also reflected in the analysis of variance study (Table 3). In this analysis, liker-in speed was demonstrated high level of significance to the amount of SFC by number (% SFCn).

Figure 4. Licker-in and cylinder speeds model contour graph plot (left) and 3D surface plots (right) - Their interaction effects on the level of Neps (cnt/g).

Table 3. ANOVA for linear model: Response SFC.

Source	Sum of Squares	df	Mean Square	F-value	p-value
Model	78.74	2	39.37	81.27	<0.0001	significant
A-Licker-in Speed	6.03	1	6.03	12.44	0.0016
B-Cylinder Speed	0.7081	1	0.7081	1.46	0.2375
Residual	12.60	26	0.4844
Lack of Fit	0.8640	1	0.8640	1.84	0.1869	not significant
Pure Error	11.73	25	0.4692
Cor Total	91.33	28

In excessively Licker-in high speed (>1350 rpm) difficulties in transferring the fibers to the cylinder was also observed which resulted in more neps generation. This poor transfer of fibers to cylinder was also resulted in the loss of good fibers as Licker-in waste. Increasing the cylinder speed from 650 rpm to 710 rpm reduced the amount neps from 260 to 231 and improved the quality of the carded sliver. However, increasing the cylinder speed beyond 710 rpm was resulted with more generation of short fibers and reduced the quality of the produced sliver. The optimum predicted value of the level of neps for processing DP-90 cotton variety is 252 cnt/g and the Licker-in and cylinder speed is 1250 rpm and 650 rpm, respectively (Figure 4).

Licker-in speed leads to better cleaning and carding but causes more waste generation and fiber damage by increasing more amount of SFC.

Therefore, the optimum predicted value of the SFC by number for processing DP-90 cotton variety is 25.8% and the Licker-in and cylinder speed is 1250 and 650 rpm, respectively.

In the ANOVA table (Table 3), the model F-value of 81.27 implies that the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise. P-value 0.0016 indicate that Licker-in speed significantly affect the percentage of SFC on the strand. This is explained by the fact that increasing Licker-in speed leads to better cleaning and carding but causes more waste generation and fiber damage by increasing more amount of SFC. Increasing the Licker-in speed more than the optimum value was also observed to be resulted in difficulties to transferring the fibers to the main cylinder. For adequate transfer of fibers, the draft between the cylinder and licker-in, it was observed to be around 1.5–1.7 for the studied DP-90 cotton variety. Poor transfer of fibers to the main cylinder was also caused by unopened fiber tufts passed on the cylinder in an erratic manner, as well as leading to the loss of good fibers as Licker-in waste.

The lack of fit F-value of 1.84 implies that the lack of fit is not significant relative to the pure error. There is a 18.69% chance that a lack of fit F-value this large could occur due to noise.

Optimizing cylinder and flats speeds interaction effects

In the Reiter Card C 60 with RSB modules, flats work with close partnership with the cylinder in carrying out carding actions. Because of the carding action between the cylinder and the flat, fibers are distributed on both surfaces.

The substantial speed difference between the two elements cylinder speed 1327 m/min (650 rpm) and flat speed 0.29 m/min (Figure 5) leads to very fast loading of fibers onto flats, causing the flats to lose their opening capacity. Flats must therefore be removed from the carding zone for cleaning, with loaded flats replaced by fresh ones. Although fiber loading occurs very quickly as the flat enters the carding zone, the flat then continues to absorb dust, neps and trash particles thrown by the cylinder throughout the rest of the process. Since the average production rate of this modern carding machine is 80 kg/h, it is imperative to use a higher flat speed of 0.29 m/min in order to effectively clean the stock by removing more trash in absolute terms. That is way as the speed of the flat increase more trash was removed from the stock which in turn improves the quality of the produced sliver.

Figure 5. Cylinder and flats speeds model contour graph plot (left) and 3D surface plots (right) - Their interaction effects on the level of trash (cnt/g).

The highest cylinder speed of 1327 m/min (650 rpm) was played a significant role in the transfer of fibers onto the doffer and improved cleaning efficiency by ejecting trashes in the form of fiber clusters onto the flat surfaces. It was observed that at the cylinder speed of 1327 m/min (650 rpm) and flats speed 0.29 m/min (Figure 3) there was a good interaction effect between the two elements which resulted by improving the quality of the produced sliver by rejecting more amount of trashes. However, increasing the cylinder and flat speeds beyond 1327 m/min (650 rpm) and 0.29 m/min, respectively, was resulted in the generation of more amount of short fibers. Therefore, when processing the DP-90 variety of cotton care has to be taken not to run the cylinder and flats at higher speed more than the attainable cleaning limits.

Increasing the cylinder speed from 650 rpm to 710 rpm and flats speed from 0.29 to 0.32 reduced the amount trash from 30 to 20 and improved the quality of the carded sliver with regard to the level of trash. However, increasing the cylinder speed beyond 650 rpm and flats speed beyond 0.29 m/min was resulted with the generation of more amount of shorter fibers and reduced CVm% and U% of the produced sliver.

The opening action of cylinder and flats depends upon both on the speed and the setting of the cylinder to the flat. There is an optimum setting for each type of varieties, depending on its fineness, dust level and tenacity. Over the entire cylinder-flat zone, the setting is gradually reduced in the direction of the material flow in order to gradually increase the opening intensity.

Narrower setting between the cylinder teeth and flats wire points resulted in intensive opening of fiber clusters with liberation of more amount of dust, but the neps and SFC was observed to increase. This could be due to the high level of stress acting on the fibers. On the other hand, a wide setting caused insufficient opening and neps disentanglement. This in turn caused an increase the neps level of carded sliver which could possibly lead to the short thick areas in the yarn.

The neps level should therefore determine the optimum cylinder-flat zone setting when processing the DP-90 variety. The optimum setting between the cylinder teeth and flats wire points was found to be 0.32 mm at the feed, 0.28 mm at the top and 0.18 mm at the delivery. This clearance setting with the cylinder and flat speed of 1327 m/min and 0.29 m/min, respectively, was found to be the predicted optimum level of dust (234 cnt/g) in the carded sliver (Figure 6).

Figure 6. Cylinder and flats speeds model contour graph plot (left) and 3D surface plots (right) - Their interaction effects on the level of dust (cnt/g).

The open-end rotor system is the only real alternative to ring spinning for producing coarser yarn counts with the successful processing of fiber at significantly higher speeds (Kaplan and Koç, 2010).

Yarn imperfection (neps, thin and thick places) are faults considered as parameters of yarn quality. Yarn imperfection of rotor spun yarn affects fabric quality significantly. The process of carding drastically changes the fiber orientation in sliver. Carding machine improves the fiber individualization and neps removing efficiency.

In the present study, the level of neps in the ginned cotton was much higher (507 cnt/g) than the level of neps of carded sliver (341 cnt/g). The level of neps in the RSB sliver was 235 cnt/g (Table 4).

Table 4. Average total number of neps, trash content and fiber length distribution.

	AFIS parameters
	Neps	Trash	L(n)	L(w)
Material	cnt/g	cnt/g	mm	mm
Ginned cotton	507	99	19.4	23.4
Card sliver	341	29	19.1	23.2
RSB sliver	235	20	19.3	23.3

Today, with the advent of higher production weaving and knitting machines, the yarn manufacturers are continually being challenged to provide high quality yarns. These yarns must be able to withstand the high stress levels induced by increased production rates. This demand for stronger yarns translates to a need for better understanding of the raw materials and their effects on yarn quality. In this research work, a sample rotor yarn of 20 Ne was produced by mixing two LOT 1 and LOT 2 bales taken from the same cotton variety DP-90. The properties of produced 20 Ne rotor yarn is presented in Table 5. The tensile, coefficient of variation of mass (CVm%) and imperfection and other properties of the produced yarn was compared with USTER statistics 95% quality level (Table 5).

Table 5. Count 20 Ne rotor yarn properties compared with USTER 95% quality level.

		Yarn parameters as tested by Tester compared with USTER statistics 95% percentile level
	Count	CVm	T	E	TiP	ThP	Neps	Hairiness
Product	(Ne)	%	cN/tex	%	−50%[/k]	+50[/k]	+280%[/k]
Yarn	20	13.3	9.86	7.12	10	72	29.13	4.8
USPL, 95%	20	14.75	10.66	10.09	17	87	13	5.5

From the test result, it can be deduced that the mechanical (both tensile and elongation) properties of the yarn and the total number of neps were relatively inferior when compared with USTER statistics 95% quality level.

These problems can only be compensated for by high initial fiber strength and optimum fiber fineness (Lawrence, C.A. 2010). To compute with the international market with reference to USTER quality levels, the spinners have to mix DP-90 local cotton variety with a variety that have greater fiber tensile property with optimum fiber fineness and profound maturity.

Conclusions

Many times, today’s competitive markets force spinning factories to find ways to raise their production rates. Sometimes these decisions are taken without a systematic approach. The optimization of speed settings of spinning machinery is one of the technically most urgent tasks when it comes to achieving the best possible raw material utilization for a high quality yarn (reflecting minimum level of defects) with increased productivity. The results of this research work showed that as the speed of the liker in increased from 1250 rpm to 1350 rpm, the coefficient of variation of mass (CVm%) of sliver increased from 3.6% to 5.62% and unevenness (U%) increased from 2.69% to 4.5%. When the Liker-in speed was increased from 1250 rpm to 1350 rpm, the amount of neps in the sliver was reduced from 260 cnt/g to 231 cnt/g. In excessively Licker-in high speed (>1350 rpm) difficulties in transferring the fibers to the cylinder was also observed which resulted in more neps generation. Increasing the cylinder speed from 650 rpm to 710 rpm reduced the amount neps from 260 to 231 and improved the quality of the carded sliver. However, increasing the cylinder speed beyond 710 rpm was resulted with more generation of short fibers and reduced the quality of the produced sliver. The optimum predicted value for processing DP-90 cotton variety, which is the main variety currently used as a raw material in many textile factories in Ethiopia, is CVm = 3.5%, U = 2.8%, level of Neps = 252 cnt/g, SFC (by number) = 25.8, Trash = 29 cnt/g and Dust = 234 cnt/g.

Research highlights

Process optimization of the carding machine C 60 RSB to produce quality sliver designed for rotor spun yarn from 100% DP-90 upland cotton was studied. Research highlights are presented hereunder:

(i) The average HVI fiber property of the cotton was: Moisture content (6.4%), Micronaire (4.2), Maturity coefficient (0.86), Upper half mean length (28.5 mm), Uniformity index (81.1), Short fiber index (10.1%), Strength 21cN/tex, Elongation (5.3%), Trash Grade (4), Colour grade (31–1) & Spinning consistency index (97.5). The number of bales participated in the mix was 118.

(ii) The study is conducted to produce 0.11Ne sliver designed for rotor spun yarn. The predicted optimum process parameters were: coefficient of variation of mass (3.5%), unevenness (2.8%), level of neps (252 cnt/g), SFC by number (25.8%), count of trash (29 cnt/g) and count of dust (234 cnt/g). This predicted optimum process parameters allows the spinner to produce quality sliver with the following USTER^Ⓡ Statistics 2023 level: 25% in SFC, 65% in level of neps, 95% in level of dust and 95% in level of trash.

(iii) The optimum machine parameters for achieving this sliver quality level was: licker in speed 1250 rpm, cylinder speed 650 rpm, flat speed 0.29 m/min, and C 60 RSB total draft 2.11.

(iv) The finding can help the spinner to estimate process parameters of C 60 RSB carding machine when processing upland cotton genotypes (varieties) with similar HVI fiber properties.

(v) The results of the study can also help the cotton breeder to breed high quality cultivars which can satisfy optimum speed requirements of modern high speed C 60 RSB carding machine.

Disclaimer

Research findings presented in this research work are the author’s contribution. The machines trade name used in this study are properly mentioned by keeping the format of standard scholarly article writing.

Ethical approval and consent

This study was part of M.Sc. thesis which was received ethical approval from Ethiopian Institute of Textile and Fashion Technology, Bahir Dar University (identification number BDU1302320).

This publishing agreement has been approved by and entered into between:

Addisu Temesgen Alamirew (M.Sc.), Department of Textile Engineering; Dire Dawa University, Dire Dawa, Ethiopia and Getnet Belay Tesema (Dr.-Ing.), Ethiopian Institute of Textile and Fashion Technology, Faculty of Textile; Bahir Dar University, Bahir Dar, Ethiopia.

Acknowledgments

Authors are thankful to the Bahir Dar Textile Share Company for their valuable cooperation during the sampling and spinning of the genotype used in this research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).