Promising Effect of Processing Parameters on Yarn Properties in Rotor Spinning

Abstract

Fabric characteristics significantly depend on the physical properties of yarn and the qualities of rotor yarn greatly governed by processing parameters. The aim of this study is to observe the effect of processing parameters such as rotor diameter and speed on the physical properties of yarn in rotor spinning process. Mixing of spinning waste with the virgin cotton is a common phenomenon in rotor spinning. 0.11 sliver hank of 100% cotton fibre with 65% virgin cotton and 35% wastage was used to produce 12 Ne yarn. The favorable impact of processing parameters on the yarn characteristics were accessed by coefficient of variation (CVm %), imperfection index (IPI), hairiness, tenacity, count strength product (CSP) and force at break. The yarn qualities were improved with increasing of rotor speed and rotor diameter.

Full text

Manufacturing Science and Technology 4(1): 11-15, 2017 http://www.hrpub.org
DOI: 10.13189/mst.2017.040102
Promising Effect of Processing Parameters on Yarn
Properties in Rotor Spinning
Rajib Al Mamun1, Md. Reazuddin Repon1,*, M. Tauhidul Islam2, K.Z.M. Abdul Motaleb1
1Department of Textile Engineering, Khwaja Yunus Ali University, Bangladesh
2Institute of Radiation and Polymer Technology, Bangladesh Atomic Energy Commission, Bangladesh
Copyright©2017 by authors, all rights reserved. Authors agree that this article remains permanently open access under the
terms of the Creative Commons Attribution License 4.0 International License
Abstract Fabric characteristics significantly depend on
the physical properties of yarn and the qualities of rotor
yarn greatly governed by processing parameters. The aim of
this study is to observe the effect of processing parameters
such as rotor diameter and speed on the physical properties
of yarn in rotor spinning process. Mixing of spinning waste
with the virgin cotton is a common phenomenon in rotor
spinning. 0.11 sliver hank of 100% cotton fibre with 65%
virgin cotton and 35% wastage was used to produce 12 Ne
yarn. The favorable impact of processing parameters on the
yarn characteristics were accessed by co-efficient of
variation (CVm %), imperfection index (IPI), hairiness,
tenacity, count strength product (CSP) and force at break.
The yarn qualities were improved with increasing of rotor
speed and rotor diameter.
Keywords Rotor Spinning, Rotor Diameter, Rotor Speed,
Hairiness, Imperfection, Yarn Strength
1. Introduction
The process of converting fibers into yarn is complex
which requires many investigations and new technical &
technological solutions [1]. There are many spinning
systems are available such as ring spinning, air vortex
spinning, friction spinning, disc spinning, solo spun
spinning, Siro spinning, air jet spinning, wrap spinning and
rotor spinning [2]. The best process of producing better
quality yarn from very poor grade of cotton and even from
wastage is rotor spinning. Rotor spinning system is rising
due to the considerable reduction in space and personnel [2-
4]. The volume of production on rotor spinning has also
increased in recent years which are quite understandable
considering the present trend in the production and
consumption of textile products [5]. Rotor spinning gives a
new era to produce more uniform, fuller, aerated and
regular in strength cotton yarn [6]. Rotor spinning is a
recognized spinning system mainly for medium and course
counts. The yarn characteristics of rotor spun yarn are
affected by many factors mainly related to raw material,
machine and processing parameters.
Many researchers have already studied the effect of rotor
and carding parameters on yarn quality from different
outlooks [7-10]. The results of several investigations have
revealed that machine parameters significantly affect the
physical and mechanical properties of yarn [11-13]. Rotor
yarns are less irregular compared to the ring spun yarn
because of multiple doubling or back doubling of fibres in
the rotor groove. In addition, rotor spun yarns are not as
affected by roller drafting wave as ring yarns [4].
No work has so far been observed on the yarn properties
produced from 65% virgin cotton and 35% wastage of 12
Ne yarn.
Widely used natural fibre in the world around 35% of
total world fibres is cotton which provides the natural
comfort, soft hand, durability, visual appeal, good
absorbency and reasonable strength [14, 15] and these are
the main reasons for selecting cotton fabrics in this study.
The objective of this experiment was to disclose the
effect of rotor speed from 35,000 to 45, 000 rpm and rotor
diameter from 43 to 66 mm on yarn characteristics and
produce the quality cotton yarn by using rotor spinning
system that can be used for weaving and knitting fabrics.
Yarn quality basis on CVm%, IPI, Hairiness, Tenacity, CSP
and force at break properties were investigated
systematically.
2. Materials and Methods
2.1. Materials
The slivers of 0.11 hank with 65% virgin cotton and 35%
wastage (10% droppings 1, 10% droppings 2, 10% noil and
5% pneumafil) were collected from Akij Spinning Mills
Limited, manikganj, Bangladesh. Table 1 indicates the
cotton fibre properties used in this experiment those were
assessed by Uster- HVI instrument according to the

12 Promising Effect of Processing Parameters on Yarn Properties in Rotor Spinning
standard testing condition [16].
Tab le 1. Properties of cotton fibre
Quality parameters Value
Spinning Consistency Index 138
Micronaire (µg/inch) 3.00
Maturity Index 0.87
Length(mm) 28.00
Uniformity Index (%) 80.0
Short fibre index (%) 8.2
Strength (g/tex) 30.4
Elongation (%) 6.0
Moisture (% ) 7.1
Reflectance (%) 75.6
Yellowness (degree) 9.3
2.2. Methods
2.2.1. Sampling
Different samples are identified as mentioned table 2.
Table 2. Sample Identification
Sample types Identification
Yarn from 43 mm rotor diameter and rotor speed
35,000 rpm
A
Yarn from 43 mm rotor diameter and rotor speed
40,000 rpm
B
Yarn from 43 mm rotor diameter and rotor speed
45,000 rpm
C
Yarn from 54 mm rotor diameter and rotor speed
35,000 rpm
D
Yarn from 66 mm rotor diameter and rotor speed
35,000 rpm
E
Figure 1. Basic principle of rotor spinning process
2.2.2. Spinning Process
Rotor spinning machine (BD 200RN, Elitex, Czech
Republic) was used. Firstly, drawn slivers were feed
through a sliver guide via a feed roller and feed plate to
rapidly rotating opening roller. The rotating teeth of the
opening roller comb out the separate fibers from the sliver
clamped between feed plate and feed roller. Then the fibers
were feed to inside wall of the rotor after completing action
in transport channel. The fibres moved forward to the rotor
groove from the conical rotor wall by centrifugal forces in
the rapidly rotating rotor. Finally, the yarn formed in the
rotor is continuously taken off by the delivery shaft and the
pressure roller through the nozzle and the draw off tube and
wound onto a cross wound package.
Figure 2. Ideal fibre assemblies with perfect evenness
2.2.3. Testing of samples
Uster Tester-5 was used to determine the unevenness and
imperfection (IPI) of the yarn at a speed of 450 m/ min. The
observed parameters were Um%, CVm%, thin places (-
50%), thick places (+50%), neps (+280%) and hairiness.
The imperfection (IPI) is the sum of no. of mass increase
(thick places), mass reductions (thin places), and short mass
increases (neps).Tensile properties viz., yarn tenacity and
force to break were measured at Uster Tensojet-4 at a speed
of 200 m/min. Average of ten tests was taken for final
result at each trial. All experiments were performed at
temperature 20 ± 2°C and relative humidity 65 ± 2%.
Yarn count was determined through the digital auto
sorter-5 linked with compute system, which gives direct
reading. Lea strength tester was used to find the lea strength
in pounds according to the ASTM (1997) method. Count
strength product (CSP) was calculated by multiplying the
yarn count with Lea strength according to the British
Standard (1985) [56]. Equation 1 was used to measure CSP.
CSP = Yarn count × Lea strength (1)
Figure 3: Principle of Uster evenness tester
3. Results and Discussion
3.1. Yarn Unevenness
3.1.1. Irregularity CVm%

Manufacturing Science and Technology 4(1): 11-15, 2017 13
The figure 4 is representing the positive impact of rotor
speed and rotor diameter on CVm% of the yarn. CVm%
were decreased with the increment of rotor speed and rotor
diameter. Concerning CVm%, the order of samples were
found as A>B>C for rotor speed and A>D>E for rotor
diameter. For rotor diameter 43 mm, the CVm% were
decreased 8.14% and 16.21% respectively for the samples
B and C as compared to A. It has been also found that at
35,000 rpm rotor speed, the CVm% were decreased 0.84%
and 6.61% respectively for the samples D and E compared
to the sample A.
Figure 4. Effect of rotor speed and diameter on yarn CVm%
3.1.2. Imperfection
Figure 5 shows the effect of rotor speed and diameter on
yarn imperfections properties. The yarn imperfection values
were decreased with the increment of rotor speed. No
chronological impacts were noticed due to increase of rotor
diameter. At higher rotor speed, the velocity of fibers inside
the transport channel increases and fibers may be
transported to the rotor groove in a substantially more
uniform way of smaller size tufts. The vice-versa relations
of imperfection and rotor speed are due to better affidavit of
individualized fibers at higher suction of air pressure [17].
Regarding imperfections, the order of samples were found
as A>B>C for rotor speed variation and D>A>E for rotor
diameter variation respectively. The imperfections were
decreased 45.51%, 51.40% and 46.26% for the samples B,
C and E respectively as compared to A. Oppositely, the
values was increased 79.91% for D.
Figure 5. Effect of rotor speed and diameter on yarn imperfection
3.1.3. Hairiness
Figure 6 illustrates the effect of rotor speed and rotor
diameter on yarn hairiness. Yarn hairiness is a complex
concept, which generally occurs because some fibre ends
protrude from the yarn body, some looped fibres arch out
from the yarn core and some wild fibres in the yarn. The
yarn hairiness H, is one of the most important parameters
influences the performance of subsequent processes like
weaving, knitting or dyeing as well as the appearance and
end use of the final fabric or garment. Rotor speed and rotor
diameter has positive and negative impact on yarn hairiness.
Regarding hairiness, the order of samples were found
C>A>B for variation of rotor speed and E>A>D for
variation of rotor diameter. The hairiness was decreased
7.80% for the sample B and 1.69% increased for the sample
C at constant rotor diameter of 43 mm. It was also found
that the hairiness was 11.18% decreased for the sample D
and 2.34% increased for the sample E at constant rotor
speed 35,000 rpm.
The higher values of rotor speed and diameter are liable
for adverse impact on hairiness. The hairiness is greatly
relies on the fiber transports to rotor and fiber collection in
the rotor groove. Centrifugal forces and a vacuum in the
rotor housing causes the fibers to disengage at a certain
point from the opening roller and to move via the fiber
channel to the inside wall of the rotor. Therefore, increased
rotor diameter boost the disengagement which result in
adverse yarn hairiness properties. Oppositely, the
centrifugal forces in the rapidly rotating rotor cause the
fibers to move from the conical rotor wall toward the rotor
groove and be collected there to form a fiber ring. So,
extremely higher rotation of rotor also enhances the
disentanglements of fibers which lead hairiness properties
as well [18].
Figure 6. Effect of rotor speed and diameter on yarn hairiness
3.2. Yarn Strength
3.2.1. Tenacity
Yarn tenacity, is one of the most important parameter
influencing the yarn’s use in terms of quality. The most
important forces acting on the yarn inside the rotor is the
centrifugal force [19]. However, higher centrifugal force
will be resulted at higher rotor speed that performs better

14 Promising Effect of Processing Parameters on Yarn Properties in Rotor Spinning
consolidation of fibers which in turn will lead to higher
yarn strength. The higher rotor speed improves the yarn
strength by ensuring better binding of fibers. From figure- 7,
it is clearly seen that yarn tenacity has been increased with
the increase of rotor speed and rotor diameter. The order of
samples were found as A<B<C in terms of tenacity due to
rotor speed variation and A<D<E was found for rotor
diameter variation. The tenacity of B and C were increased
by 32.53% and 54.62% respectively with respect to A.
Equally, the tenacity 18.61% increased for D and 31.21%
increased E compared to the sample A at constant rotor
speed.
Figure 7. Effect of rotor speed and diameter on yarn tenacity
3.2.2. Count Strength Product
Rotor speed and rotor diameter have significant effect on
the yarn count strength product (CSP). From figure 8, it is
clearly evident that, the CSP increase with the increment of
rotor speed and rotor diameter. The order of samples were
found as A<B<C in terms of CSP due to rotor speed
variation A<D<E was found for rotor diameter variation..
The CSP values of B and C were increased by 17.57% and
27.41% respectively with respect to A. Conversely, the CSP
value 18.69% increased for 54 mm diameter and 28.88%
increased for 66 mm diameter compared to the sample
produced from 43mm diameter at constant rotor speed of
35,000rpm.
Figure 8. Effect of rotor speed and diameter on yarn CSP
3.2.3. Force to Break
Figure 9 demonstrates the effect of rotor speed and rotor
diameter on yarn force to break. The value of force to break
was increased with the increasing values of rotor speed and
rotor diameter. The force to break was 34.87% and 50.76%
higher for the samples B and C respectively with respect to
sample A, at constant diameter of 43mm. In case of rotor
diameter, at constant rotor speed of 35,000 rpm, the force to
break of yarn 17.83% increased for the sample D and
40.79% increased for the sample E contrasted to the sample
A.
Figure 9. Effect of rotor speed and diameter on yarn force to break
4. Conclusions
Significant effect of processing parameters such as rotor
speed and rotor diameter on the yarn properties in rotor
spinning was studied. The unevenness such as CVm%, total
imperfection index (IPI) and hairiness were improved with
augmentation of rotor speed from 35,000 to 45,000 rpm at
constant rotor diameter 43 mm. Conversely, reverse
scenario observed due to increment of rotor diameter from
43 to 66 mm at constant rotor speed of 35,000 rpm. It
appears that the yarn strength i.e. tenacity, CSP and force at
break were increased with the increase rotor diameter and
running speed. On the basis of imperfections and hairiness
the yarn quality tends to deteriorate when the rotor diameter
increases from 43 to 54mm and rotor speed increases from
40,000 to 45,000 rpm respectively. Further work could be
done on producing quality yarn of various counts from
other natural, synthetic and blends fibres to justify this
analysis.
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