Impact of Carding Parameters and Draw Frame Doubling on the

Transcription

Impact of Carding Parameters and Draw Frame Doubling
on the Properties of Ring Spun Yarn
Abdul Jabbar, Tanveer Hussain, PhD, Abdul Moqeet
National Textile University, Faisalabad, Punjab PAKISTAN
Correspondence to:
Tanveer Hussain email: [email protected]
ABSTRACT
The impact of card cylinder speed, card production
rate and draw frame doubling on cotton yarn quality
parameters was investigated by using the BoxBehnken experimental design. It was found that yarn
tenacity, elongation and hairiness increase by
increasing the number of draw frame doubling up to a
certain level and then decrease by further increase in
doubling. Yarn unevenness increased by increasing
card production rate and total yarn imperfections
increased by decreasing card cylinder speed and
increasing card production rate.
and draw frame delivery speed, and that an increase
in card draft beyond a certain point leads to
deterioration in yarn quality [3]. The percentage of
leading and trailing fiber hooks in the roving fed to
the ring frame also affects the yarn quality. It has
been found that percentage of trailing, leading and
total fiber hooks decrease with the increase in card
coiler diameter, card draft, and draw frame delivery
speed [4-5].
The effect of lap hank, card draft, speed frame draft,
and ring draft on the physical and tensile properties
of yarns has also been investigated. It was found that
yarn spun at higher speed frame draft and
corresponding lower ring frame draft has better
tenacity, breaking elongation and evenness in
comparison to yarn spun at lower speed frame draft
and higher ring frame draft. It was also noted that
card draft followed by lap hank is a major
contributing factor influencing the changes in yarn
properties [6-7]. Increasing carding rate and total
spinning draft improves the yarn strength and
evenness, whereas lowering spindle speed results in a
stronger and more uniform yarn with fewer
imperfections [8].
Keywords: Spinning; carding; drawing; cotton yarn
INTRODUCTION
Ring spinning is one of the most commonly used
spun yarn manufacturing technologies for producing
high strength carded and combed cotton yarns in the
widest range of linear densities. Various processes
involved in the spinning of carded spun yarn include
cleaning and blending cotton in the blow room,
carding, breaker and finisher drawing, roving
formation on the simplex and yarn formation on the
ring frame. The effect of different parameters of these
processes on the resulting yarn quality, have been
studied by various researchers in the past.
The influence of spindle speed on yarn strength,
breaking elongation, imperfections and hairiness has
also been investigated. It has been reported that the
yarn tenacity improves whereas imperfections,
hairiness and breaking elongation deteriorate with the
increase in spindle speed [9]. The influence of fiber
friction, top arm pressure, and roller settings at
various drafting stages, namely, draw frame, roving
frame, and ring frame has also been studied [10], and
it has been found that top arm pressure and roller
settings at all three drafting stages affect the yarn
properties in a similar way, and that fiber-to-fiber
friction is a leading factor influencing the tensile
properties of ring spun yarn.
The effect of fiber opening in the blow room on the
yarn quality has been studied and it has been found
that increase in fiber opening in the blow room
results in improvement in yarn tenacity and yarn
imperfections (IPI) up to a certain level of opening,
beyond which these parameters deteriorate sharply
[1]. Similarly, fiber openness at carding also results
in improvement in yarn irregularity and tenacity only
up to a certain level and then these parameters
deteriorate on further increase in fiber openness [2].
Card draft, coiler diameter and draw frame delivery
speed are also found to have significant effect on
yarn properties. It has been reported that yarn
tenacity, breaking elongation, evenness and hairiness
are improved with increase in card coiler diameter
Journal of Engineered Fibers and Fabrics
Volume 8, Issue 2 – 2013
72
http://www.jeffjournal.org
The carding process has a vital role in the production
of staple spun yarn and has significant effect on the
properties of the resulting yarn. In addition, drawing
and doubling at the subsequent production stages also
play an important role in determining the consequent
yarn quality. It is evident from the literature review
that previous work does not reveal the impact of
preparatory process variables such as card cylinder
speed, production rate, and number of draw frame
doubling on the quality of ring spun yarn. This study
was carried out to fill this gap using the Box Behnken
statistical design of experiments.
All yarn samples were prepared by using Reiter C 60
Card, Reiter SB-2 Breaker Draw Frame, Reiter RSB35 Finisher Draw Frame, FA 458ASpeed Frame, and
FA 1520 Ring Frame. The linear densities of the
prepared card sliver, finished sliver, and roving were
6.38 ktex, 5.95 ktex, and 0.738 ktex respectively. The
yarn samples of 24tex were prepared from these
rovings at a spindle speed of 18500 rpm with a twist
multiplier of 4.54.
Before testing, all the prepared yarn samples were
conditioned in the laboratory under standard
atmospheric conditions of 21±1°C and a relative
humidity of 65±2 for 24 h. A Zweigle G 566
hairiness tester was used to measure distribution of
hairs per unit length on the yarn surface according to
ASTM D5647-01. Only the hairiness parameter ‘S3’
(number of hairs greater than 3mm) was considered,
which is known to significantly affect the appearance
and performance of yarns.
MATERIALS AND METHOD
Three process variables, card cylinder speed (rpm),
card production rate (kg/hr), and number of
doublings at breaker drawing, were selected for
experimentation. Coded levels and actual values of
these variables are given in Table I.
TABLE I. Experimental factors and their levels.
Yarn unevenness and imperfections were determined
by using Uster Tester-4 according to ASTM D 142596. Total yarn imperfections (IPI) were calculated by
adding -50% thin, +50% thick and +200% neps. A
Uster Tensojet-4 was used determine the breaking
elongation and tenacity of yarn samples according to
ASTM D-76.
RESULTS AND DISCUSSIONS
The complete Box-Behnken experimental design and
the yarn test results are given in Table II. The
experimental design and statistical analyses were
performed using the Minitab16® statistical software
package. The regression coefficients and p-values of
all the terms are given in Table III. The terms with pvalues less than 0.05 are considered statistically
significant with 95% confidence. The regression
equations, considering the actual values of input
variables, are given in Table IV for all the response
variables. The R2 values give the percentage of
variation in the response variables that can be
explained by the factors/terms included in the
regression equations. The impact of all the factors on
each response variable is separately discussed in the
following sections.
Yarn samples were prepared according to the
combinations of different factor levels as determined
by Box-Behnken factorial experimental design. BoxBehnken is one of the most advanced response
surface methodology (RSM) experimental designs
employed to understand the quantitative relationships
between multiple input variables and response
variables.
Pakistani Cotton with upper half mean length of
27.18 mm, strength of 31.5 g/tex, elongation of 5.8 %
,and micronaire of 4.6 µg/inch respectively, was used
to prepare the yarn samples of 24 tex linear density.
73
TABLE II. Box-Behnken experimental design and yarn test results.
S. No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Factors/Input
x1
x2
x3
-1
-1
0
1
-1
0
-1
1
0
1
1
0
-1
0
-1
1
0
-1
-1
0
1
1
0
1
0
-1
-1
0
1
-1
0
-1
1
0
1
1
0
0
0
0
0
0
0
0
0
Hairiness (S3)
1081.1
1324.7
1222.91
1224.3
331.4
733.9
485.2
815.4
1204.5
377.5
1491.6
466.1
1643
1579
1480
Um (%)
11.5
11.42
12.16
12.02
11.93
11.95
11.91
11.73
11.66
12.27
11.45
11.95
11.76
11.39
11.77
Responses/Output variables
IPI
Elongation (%)
426
4.26
277
4.42
565
4.42
475
4.28
491
3.67
382.5
3.63
536
3.69
368
3.78
332
3.96
612.5
3.62
332
4.42
538.5
3.68
451
4.4
340
4.29
391
4.35
Tenacity (RKM)
18.29
17.97
17.12
17.46
17.29
16.35
16.77
16.11
16.59
17.1
15.64
16.54
17.81
17.68
18.11
TABLE III. Regression coefficients for different response variables using coded values of the input variables.
Term
x1
x2
x3
x12
x22
x32
x1x2
x1x3
x2x3
Hairiness (S3)
Coeff.
P-Value
122.21
0.322
-226.39
0.097
76.38
0.523
-323.77
0.105
-30.32
0.860
-652.09
0.010*
-60.55
0.716
-18.08
0.913
-49.63
0.765
Coeff.
-0.0475
0.2962
-0.0962
0.0913
0.0437
0.1487
-0.0150
-0.0500
-0.0275
Um%
P-Value
0.402
0.002*
0.123
0.286
0.591
0.109
0.846
0.526
0.723
IPI
Coeff.
-64.438
103.000
103.000
16.188
25.563
34.188
14.750
-14.875
-18.500
P-Value
0.011*
0.001*
0.751
0.528
0.333
0.212
0.549
0.545
0.457
Elongation (%)
Coeff.
P-Value
0.00875
0.899
-0.13250
0.100
0.08625
0.246
-0.11458
0.289
0.11292
0.296
-0.53958
0.003*
-0.07500
0.456
0.03250
0.741
-0.10000
0.331
Tenacity (RKM)
Coeff.
P-Value
-0.1975
0.381
-0.0337
0.876
-0.2838
0.226
0.0029
0.993
-0.1596
0.620
-1.2396
0.009*
0.1650
0.595
0.0700
0.819
0.0975
0.751
*Statistically significant terms
TABLE IV. Regression equations for different response variables using actual values of the input variables.
No.
Yarn properties
Regression equation
R2 (%)
1
Hairiness
83.25
2
Um%
3
IPI
4
Elongation (%)
5
Tenacity (RKM)
-48469.3 +57.13x1 +42.94x2 +8294.22x3 -0.032x12 -0.076x22
-652.09x32 -0.03x1x2 -0.18x1x3 -2.48x2x3
19.58 -0.011x1 +0.007x2 -1.34x3 +9.12x12*10-6 +0.0001x22 + 0.148x32
-7.5x1x2*10-6 -5x1x3*10-4 -0.0013x2x3
2653.94 -3.08x1 -7.98x2 -204.19x3 +0.002x12 +0.064x22 +34.18x32
+0.007x1x2 -0.149x1x3 -0.93x2x3
-23.95 +0.02x1 -0.003x2 +6.80x3 -1.14x12*10-5+0.0003x22 -0.54x32
-3.75x1x2*10-5 +0.00032x1x3 -0.005x2x3
-14.22 -0.0149x1 -0.0171x2 +13.54x3 +2.91x12 -3.99x22 -1.24x32
+8.25x1x2*10-5 +0.0007x1x3 +0.005x2x3
Yarn Hairiness
Surface plots depicting the effect of card production
rate, card cylinder speed, and draw-frame doubling
on yarn hairiness are given in Figure 1(a, b, c). It is
clear from the Figure 1(b, c) that yarn hairiness
increases with the increase in draw frame doubling
up to a certain point and then decreases with any
89.49
92.41
89.40
80.24
further increase in this parameter. Hairiness is low
when the draw frame doubling is 5 or 7, while it is
higher when the draw frame doubling is 6. If we look
at Table II, the hairiness values vary from 331.4 to
1643 at different combinations of input variables,
with draw frame doubling (x3) being the main
74
The trend in the results may be explained by a
decrease in inter-fiber cohesion with the increase in
doubling from 5 to 6, due to fibers straightening up to
a doubling level of 6. Less inter-fiber cohesion allows
the fibers to easily come out from the fiber strand
leading to increase in yarn hairiness. Beyond the
doubling level of 6, fiber parallelization decreases
with an increase in sliver weight resulting in increase
in inter-fiber cohesion. The effect of card production
rate and cylinder speed on yarn hairiness was not
found to be statistically significant with 95%
confidence level (p-value > 0.05, Table III).
influencing factor. The average hairiness for
experiments with 5 doublings is 661, for
experiments with 6 doublings it is 1365 and for
7 doublings it is 814. This difference is not just
statistically significant but also practically
significant. The yarns with high hairiness may result
in a greater amount of fabric pilling and surface
fuzziness as compared to the yarns with lower
hairiness.
FIGURE 1. Effect of card cylinder speed, card production rate and draw frame doubling on yarn hairiness.
Yarn Unevenness
Figure 2(a, b, c) depicts the effect of card cylinder
speed, card production rate, and draw frame doubling
on yarn unevenness. It is clear from Figure 2(a, c)
that yarn unevenness increases with an increase in the
card production rate. As the card production rate is
increased from 80 to 120 kg/hr, there is a steady
increase in the yarn unevenness (Um%) from an
average value of 11.5 at 80 kg/hr production rate to
12.1 at 120 kg/hr production rate. It is evident from
the trend that the yarn unevenness is directly
proportional to the card production speed and the
spinner should increase the card production rate with
caution. The trend in the results can be explained as
follows: the higher production rate results in poor
carding, higher cylinder-loading and more leading
fiber-hooks in the carded sliver. Ultimately, roving
with higher leading fiber-hooks is forwarded to the
ring frame contributing to an increase in yarn
unevenness. The effect of card cylinder speed and the
draw frame doubling was not found to be statistically
significant (p-value > 0.05, Table III). According to
the existing theoretical models published on the
effect of doubling on mass irregularity, the yarn
unevenness decreases by increasing the number of
doublings [11]. This decreasing trend can be seen in
Figure 2b at 900 rpm. However, the effect was not
found to be statistically significant in the present
study when the number of doubling is increased from
5 to 7. One reason for a little deviation from the
theoretical models may be that the theoretical models
assume the card production rate and cylinder speed to
be same for different number of doublings while in
the present study, those factors were also taken as the
input variables.
75
FIGURE 2. Effect of card cylinder speed, card production rate and draw frame doubling on yarn unevenness.
Total Yarn Imperfections
Surface plots expressing the effect of card production
rate, card cylinder speed, and draw frame doubling
are shown in Figure 3(a, b, c). It is evident from
Figure 3 (a, b, c) that total yarn imperfections (IPI)
increase as the card production rate increases from 80
kg/hr to 120 kg/hr, and also as the card cylinder
speed decreases from 900 rpm to 700 rpm. An
increase in card production rate results in a heavier
operational fiber layer on the card cylinder surface,
higher cylinder loading, and more nep generation due
to poor carding action. Hence, the poor carding
action at higher production rate results in higher total
yarn imperfections. The decrease in total
imperfections with the increase in card cylinder speed
can be explained by good carding and nep removal at
the carding stage. At higher carding-cylinder speeds,
better carding action results in a decrease in total yarn
imperfections. A variation in total imperfections from
277 to 612 (see Table II) with different combinations
of input variables is not just statistically significant
but also practically significant. A yarn with higher
number of yarn imperfections will ultimately result in
poor fabric appearance. The average value of IPI is
504 with experiments having 700 rpm card
cylinder speed, and 375 with experiments having
900 rpm cylinder speed. Such a difference is
both statistically and practically significant.
Similarly, average value of IPI is 341 with
experiments having 80kg/hr production rate, and
547 with experiments having 120 kg/hr
production. Again, such a difference is both
statistically and practically significant. Draw
frame doubling was not found to have a statistically
significant effect on total yarn imperfections (p-value
> 0.05, Table III).
FIGURE 3. Effect of card cylinder speed, card production rate and draw frame doubling on yarn imperfections (IPI).
lower when the doubling is 5 or 7. This behavior can
be explained by the improvement in fiber
parallelization due to increase in draft up to 6
doublings. After that when the doubling is further
increased to 7, fiber parallelization decreases due to
too large an increase in sliver weight. Increase in
fiber parallelization in sliver improves the yarn
breaking elongation. The results at different
combinations of input variables show a variation in
Yarn Breaking Elongation
Figure 4(a, b, c) depicts the effect of card cylinder
speed, card production rate and draw frame doubling
on breaking elongation of the yarn. It is clear from
Figure 4(b, c) that as the draw frame doubling
increases, breaking elongation of yarn increases upto
a certain point and then decreases with a further
increase in doubling. Yarn breaking elongation is
higher when the draw frame doubling is 6, while it is
76
elongation from 3.62% to 4.42%. This difference is
not just statistically significant but also practically
significant. The higher the yarn elongation%, the
better it will be able to withstand stresses during
weaving, resulting in less yarn breakages on the loom
and higher weaving efficiency. The effect of cylinder
speed and production rate on yarn breaking
elongation was not found to be statistically
significant (p-value > 0.5, Table III).
FIGURE 4. Effect of card cylinder speed, card production rate and draw frame doubling on yarn breaking elongation.
Yarn Tenacity
Surface plots in Figure 5(a, b, c) show the effect of
card cylinder speed, card production rate, and draw
frame doubling on the yarn tenacity. It can be seen
from Figure 5(b, c) that the yarn tenacity increases
with an increase in draw frame doubling up to a
certain level and then decreases with a further
increase in doubling. Yarn tenacity is higher when
the draw frame doubling is 6, while it is lower when
the doubling is 5 or 7. Sliver doubling improves fiber
straightening and parallelization by the increase in
draft up to a certain level and beyond that level, fiber
parallelization decreases with an increase in
sliver weight due to the increase in sliver doubling.
Hence, at an appropriate level of doubling of 6, the
fiber parallelization is optimal, resulting in high yarn
tenacity. Although the improvement in yarn tenacity
at 6 doublings does not in itself look much as
compared to 5 or 7 doublings, when combined with
the simultaneous improvement in yarn elongation as
discussed in the previous section, it plays a
significant role in reducing the yarn breakages on the
loom, thus increasing weaving efficiency. According
to the analysis of variance, the effect of card
production rate and card cylinder speed was not
found to be statistically significant on the yarn
tenacity (p-value > 0.5, Table III).
FIGURE 5. Effect of card cylinder speed, card production rate and draw frame doubling on yarn tenacity.
CONCLUSIONS
Increase in card cylinder speed significantly
decreases the yarn IPI, without significantly affecting
any other yarn parameter. An increase in card
production rate results in a significant increase in
yarn IPI as well as yarn unevenness. The number of
draw frame doublings not only significantly affecst
the yarn tenacity and elongation, but also yarn
hairiness. However, the effect of draw frame
doubling is not linear. By increasing the number of
doubling up to a certain level, the yarn tenacity,
77
[10] Das, A.; Ishtiaque, S. M.; and Niyogi, R.;
“Optimization of fiber friction, top arm
pressure and roller setting at various drafting
stages”Textile Research Journal, 76, 2006,
913-921.
[11] Martindale, J.G.; “A new method of measuring
the irregularity of yarns with some
observations on the origin of irregularities in
worsted slivers and yarns”, Journal of the
Textile Institute, 36, 1945, T35-47.
elongation and hairiness increase, but on a further
increase in number of doubling, the trend is reversed.
ACKNOWLEDGEMENT
The authors would like to thank Mr. Shahzad
Hashmi, General Manager Best Exports (Pvt) Ltd
Faisalabad for providing opportunity and support to
prepare yarn samples for this study and Mr. Asif
Javed General Manager Nishat Mills Ltd unit #1
Faisalabad for providing the facility of testing yarn
samples.
AUTHORS’ ADDRESSES
Abdul Jabbar
Tanveer Hussain, PhD
Abdul Moqeet
National Textile University
Sheikhupura Road
Faisalabad, Punjab 37610
PAKISTAN
REFERENCES
[1] Ishtiaque, S. M.; Chaudhuri, S.; and Das, A.;
“Influence of fiber openness on processibility
of cotton and yarn quality. Part I: Effect of
blow room parameters” Indian Journal of
Fibre & Textile Research, 28, 2003, 399-404.
[2] Ishtiaque, S. M.; Chaudhuri, S.; and Das, A.;
“Influence of fiber openness on processibility
of cotton and yarn quality. Part II: Effect of
carding parameters” Indian Journal of Fibre &
Textile Research, 28, 2003, 405-410.
[3] Ishtiaque, S. M.; Mukhopadhyay, A.; and
Kumar, A.; “Influence of drawframe speed and
its preparatory on ring yarn properties”Journal
of the Textile Institute, 99, 2008, 533-538.
[4] Garde, A. R.; Wakankar, V. A.; and Bhaduri, S.
N.; “Fiber configuration in sliver and roving
and its effect on yarn quality” Textile Research
Journal, 31, 1961, 1026-1036.
[5] Ishtiaque, S. M.; Mukhopadhyay, A.; and
Kumar, A.; “Impact of carding parameters and
drawframe speed on fiber axial distribution in
ring spun yarn” Indian Journal of Fibre &
Textile Research, 34, 2009, 231-238.
[6] Kumar, A.; Ishtiaque, S. M.; and Salhotra, K. R.;
“Analysis of spinning process using the
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rotor and air-jet yarns” Journal of the Textile
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[7] Kumar, A.; Ishtiaque, S. M.; and Salhotra, K. R.;
“Analysis of spinning process using the
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ring, rotor and air-jet yarns” Journal of the
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[8] Lee, J. R.; and Ruppenicker, G. F.; “Effect of
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[9] Lawal, A. S.; Nkeonye, P. O,; and Anandjiwala,
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Impact of Carding Parameters and Draw Frame Doubling on the

Transcription

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