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CHAPTER V
YARN QUALITY PARAMETERS OF IMPROVEDCHARKHA
Yarn Quality plays an important part in determining the working
of the loom, appearance of the cloth woven and ultimately the price of
cloth. Better the yarn quality more is the yarn demand for the yarn
and higher will be the market price for good quality yarns. SITRA has
evolved quality standards or Norms for the cotton yarns spun. The
yarns that are produced on the different charkhas have been
ultimately compared for quality against SITRA Norms to see we ,ther
they meet the quality requirements. The quality particulars have been
evaluated for each count that is spun on the charkha
5.1 Yarn Quality Parameters To Be Tested andEvaluated
Yarn samples were spun on all the 3 types of spinning
machines namely 8 Spindle Hand Operated Charkha, 8 Spindle
Motor Operated Charkha and 16 Spindle Improved Charkha. The
roving bobbin of 0.90 hank was taken to Spin 10s' and 33s Nm and
1.20 hank roving was used to spin 64s and 72s Nm. The Spindle
speeds were kept at 5500 rpm and 6500 rpm. Only when the speed
exceed 6500 rpm and above the yarn quality deteriorated due to
excessive end breakages and it was not practical to run the
machine at speeds exceeding 6500 rpm as the stoppage time of the
machine to repair broken threads has become very high. A total of
139
\
20 readings for each count was taken to get the average yarn
quality characteristics like CV% of TPI, U%, Thin place/km, Thick
place/km, Neps/km, Rkm values, % of Elongation and Hairiness
Index. The quality particulars of the yarn have been tested and the
results have been analyzed. It can be seen from the test results that
there is vast improvement in yarn quality, obtained with yarn
produced on improved charkha and the quality levels are
comparable with SITRA* norms for mill made yarn of similar counts.
There is also appreciable improvement in yarn quality when shifts
are made from Hand-Operated Charkha to Motorized charkha and
16 Spindle Improved Charkha for all counts. This is because of the
uniform twist flow to the yarn during charkha spinning as the
spindles are driven by motor; this ensures constant speed of
rotation of the machine parts. This stabilization of TPI has yielded
better yarn quality.
5.2.0 Yarn Quality Characteristics
5.2.1 Yarn Quality Characteristics Of 10s Nm spun on charkhas
(5500 rpm and 6500 rpm)
10s Nm** count was spun on the selected charkhas with 5500
rpm and 6500 rpm of spindle speeds .The quality particulars of 10s
Nm count are obtained from 8 Spindle Hand Operated Charkha, 8
Spindle Motor Operated Charkha and 16 Spindle Improved Charkha
are compared with SITRA norms.
* SITRA - South India Textile Research Association, Coimbatore
140
The TPI (Twist Per Inch) 10.0 is given to the yarn, which is kept
constant for all the charkhas.
The trial was taken on 8 Spindle Hand Operated Charkha, 8
Spindle Motor Operated Charkha, 16 Spindle Improved Charkha on
10s Nm at a constant speed of 5500 rpm and 6500 rpm. The yarn
was tested for various parameters like CV% of TPI, U%, Thin
places/km, Thick places/km, Neps/km, Rkm values, Percentage of
Elongation and Hairiness Index. Average of 20 readings for each
quality particulars is given in the Table- 5.1 and 5.2.
5.2.2 CV% of TPI
CV % of TPI affect the working of the yarn in looms. Lower
CV% of TPI is preferable. From the Table -5.1 it is evident that the
CV% of TPI are higher in the yarns made out of 8 Spindle Hand
Operated Charkha, this is because of irregular rotation of handle of
the machine. But the 8 Spindle Motorised Charkha shows 22.4
percentage improvement when compared to 8 Spindle Hand
Operated Charkha. Similarly the CV% of TPI shows 64.2 percentage
improvement in 16 Spindle Improved Charkha when compared with
Hand Operated Charkha and 53.9 percentage improvement when
compared with 8 Spindle Motor Operated Charkha. Even when the
speeds of the charkha were increased to 6500 rpm in Table - 5.2, it
is observed that there is a 30 percentage improvement in CV% of TPI
in the 16 Spindle Improved Charkha.
** Nm - Metric System Of Yarn Numbering
141
5.2.3 U%
U % means uniformity index of the yarn tested is lister
evenness tester (Evenness of yarn). The lower U% means better
quality. The U% rating of 8 Spindle Hand Operated Charkha yam
shows higher values than other two charka yarns. The.re is a 15.3
percentage improvement of U% in the 16 Spindle Improved Charkha
when compared with 8 Spindle Hand Operated Charkha in Table-
5.1. However the SITRA norms give lower values. Among the three
charkhas, 16 spindle motor operated charkha yielded better yarn with
16.56 U% for 10s Nm at 5500 rpm.
5.2.4 THIN PLACES/Km
Table - 5.1 indicates the performance of 10s Nm yarn in terms
of thin places (Yarn imperfections). There is a 82.2 percentage
improvement in the yarn imperfections for 10s Nm count at 5500 rpm
of spindle speeds, between hand operated 8 spindle yarn and 16
Spindle Charkha. The 16 Spindle Charkha has given better quality
than SITRA norms. The 8 Spindle Hand Operated Charkha shows
higher values because of the irregular motion of charkha and jerky
rotation of fluted rollers. But, the 16 Spindle Improved Charkha shows
4 percentage improvement when compared with 8 Spindle Motor
Operated Charkha and 82.2 percentage improvement when
compared with Hand Operated Charkha, because of smooth rotation
of drafting rollers and no vibration in improved machine. This has
confirmed that 16 spindle improved charkha has yielded better results
among the charkhas selected for the study. Even at higher speeds of
144
6500 rpm in Table - 5.2, there continues to be reduction of thin
places in yarn spun on improved charkha.
5.2.5 THICK PLACES/Km
Table - 5.1 indicates the performance of thick places at 5500
rpm {Yarn imperfections). There is a 48.6 percentage improvement in
the yarn imperfections for 10s Nm count between 8 spindle hand
operated and 8 spindle motor operated. The 16 Spindle Charkha has
given better quality than SITRA norms and the 16 spindle charkha
has yielded better yarn showing an improvement of 53 percentage
over hand operated charkha yarn and 3.5 percentage improvement
over 8 spindle motor operated charkha yarns. Even at 6500 rpm the
thick places have come down in 16 Spindle Improved Charkha in
Table - 5.2. This was because of smooth rotation of drafting rollers
and no vibration in 16 spindle-improved charkhas.
5.2.6 IMEPS/Km
Neps are defined as entanglement of immature fibers into small
ball the size of a pinhead. The neps undesirable both in the yarn and
the fabric as theyappear as fabric defect. These neps do not qbserii'
the dye applied on to the fabric uniformly, because they consist of
immature fibers. Therefore steps are taken to reduce the nep
generation in the spinning process. It is the blow room and the
carding departments that contribute to nep generation. The neps of
16 Spindle improved Charkha shows 3.48 percentage improvement
in yarn imperfections when compared with 8 Spindle Hand Operated
145
Charkha however the SITRA norms are better probably because
better collons are used in the mills and latest spinning machinery are
available in the mills. Neps generation has been attributed to mainly
the beater speeds, settings in blow room and carding settings
between feed plate and taker in.
5.2.7 TOTAL IMPERFECTIONS/Km
The total imperfections are the sum of thin place, thick place
and neps/Km of yarn. It goes to show the total yarn defects in a
Kilometer of yarn length. Total imperfections influences loom
performance and over all fabric appearance. Less number of
imperfections in yarn is preferred for better yarn quality. The Table-
5.1 indicates that the total imperfections of 10s Nm count shows 57.1
percentage improvement when compared between 8 spindle hand
operated and 16 spindle improved charkhas and 3.6 percentage
improvement in the 16 Spindle Improved Charkha when compared
with 8 Spindle Motor Operated Charkhas. At speeds of 6500 rpm in
Table - 5.2, it is noticed that the total imperfections in 16 Spindle
Charkha is comparable to SITRA quality standards.
5.2.8 RKM VALUES
Stronger the yarn, higher will be the RKM value. Stronger yarns
produce stronger cloth and spin better without end breakage. The
RKM value of 16 Spindle Improved Charkha shows 31.8 percentage
and 4.8 percentage improvement when compared with 8 Spindle
Hand Operated Charkha and 8 Spindle Motor operated Charkha
146
respectively at 5500 rpm of spindle speed for 10s Nm. From this
table, the 16 Spindle Improved Charkha values are higher than 8
Spindle Motor Operated Charkha, because of uniform motor speed
and also less vibration of machine. Here the RKM values of different
Charkhas are equal to SITRA norm values. So the higher RKM
means stronger yarns. Hence, it can be inferred that 16 Spindle
Improved Charkha is giving better yarn strength than ring spun yarns.
It can be observed in all the counts spun on the 16 Spindle Charkha,
Rkm values are good and comparable to SITRA quality standards.
5.2.9 PERCENTAGE OF ELONGATION
From the table - 5.1 for 10s Nm Count, it is clear that the
percentage of elongation of 8 Spindle Motor Operated Charkha value
shows 2.6 percentage improvement when compared with Hand
Operated Charkha. There is 4.8 percentage deterioration in
elongation of yarn when compared with 8 Spindle and 16 Spindle
Motor Operated Charkhas. The SITRA norms shows a higher
elongation at break probably because of better raw material used in
spinning mills and also better technology in the blow room and
carding departments.
5.2.10 HAIRINESS INDEX
There is not much improvement in hairiness index in all the
machines when compared with SITRA Norms. The factors
contributing to hairiness in yarn are type of cotton used, processing
parameters, speed of machines, ring and traveller combination etc. If
147
these items are taken care of we can reduce hairiness in the
improved 16 Spindle Charkha yarns.
5.3 Yarn Quality Characteristics of 33s Nm spun on
Charkhas (5500 rpm and 6500 rpm)
5.3.1 33s Nm count was spun on the charkhas using 5500 rpm
and 6500 rpm of spindle speeds. The quality particulars of 33s Nm
count are obtained at 5500 rpm spindle speed by using 8 Spindle
Hand Operated Charkha, 8 Spindle Motor Operated Charkha and 16
Spindle Improved Charkha are compared with SITRA norms in Table
- 5.3. Similarly the charkha speeds were kept at 6500 rpm and 8
Spindle Motor Operated and 16 Spindle Improved Charkha were
compared for quality particulars with SITRA norms. The TPI given to
yarn was 18.0. It was kept constant for all the machines. . .
The yarn was tested for various parameters like CV% of TPI,
U%, Thin places/km, Thick places/km, Neps/km, Rkm values,
Percentage of Elongation and Hairiness Index. Average of 20
readings for each quality particulars is given in the Table- 5.3 and 5.4.
5.3.2 CV% of TPI
From the above table - 5.3, it is evident that the CV% of TPI
are higher in 8 Spindle Hand operated Charkha; this is because of
irregular rotation of handle of the machine. But the 16 spindle
improved charkha shows 37.2 percentage improvement when
compared to 8 Spindle Motor Operated Charkha.
148
There is also a 57.6 percentage improvement in CV% of TPI when
compared with Hand Operated Charkha. This is because there is a
uniform twist flow between the nip of the front roller and traveller
because of motorization of charkha. When the speeds are raised to
6500 rpm in Table-5.4, there is a 43.5 percentage improvement in the
CV% of TPI when compared with 8 Spindle Motor Operated Charkha.
5.3.3 U%
U % means uniformity ratio (evenness of yarn). The lower U%
means better quality. The U% of 8 Spindle Hand Operated Charkha
shows higher values than other two charkhas. There is a ,28.07
percentage improvement in U% in the 16 Spindle Improved Charkha
when compared with 8 Spindle Hand Operated Charkha in Table -
5.3. The achievement of U% results in the 16 Spindle Charkha is
better than SITRA Norms. At 6500 rpm of spindle speed, the 33s Nm
colint has shown a 9.6 percentage improvement in U% over 8
Spindle Motorised Charkha.
5.3.4 THIN PLACES/Km
Table 5.3 indicates the performance of thin places (Yarn
imperfections). There is a 82.7 percentage improvement in the yarn
imperfections (thin places) for 33s Count in the 16 Spindle Charkha
when compared with the results of 8 Spindle Hand Operated
Charkha. The 16 Spindle Charkha values comparable to SITRA\
norms. The 8 Spindle Hand Operated Charkha shows higher values
because of the irregular motion of charkha and jerky rotation of fluted
151
rollers. But, the 16 Spindle Improved Charkha shows 20.9 percentage
improvement when compared with 8 Spindle Motor Operated
Charkha, because of smooth rotation of drafting rollers and no
vibration in the improved machine. At 6500 spindle speed for 33s Nm
count, there is 16.6 percentage improvement over 8 Spindle Motor
Operated Charkha in Table-5.4.
5.3.5 THICK PLACES/Km
Table - 5.3 indicates the performance of thick places (Yarn
imperfections). There is a 71.2 percentage improvement in the yarn
imperfections (thick place) if we compare the performance of 16
Spindle Improved Charkha with 8 Spindle Hand Operated Charkha.
There is also a 12 percentage improvement in 8 Spindle Power
Operated Charkha when compared with 8 Spindle Hand Operated
Charkha. The 16 Spindle Charkha has given better quality than
SITRA norms. The 8 Spindle Hand Operated Charkha shows higher
values because of the irregular motion of charkha and jerky rotation
of fluted rollers. Table - 5.4 indicates the speeds at 6500 rpm for 33s
Count. There is a 26.6 percentage improvement in thick places when
compared to 8 Spindle Motor Operated Charkha.
5.3.6 NEPS/Km
The neps of 16 Spindle Improved Charkha shows 3.3
percentage improvement in yarn imperfections when compared with 8
Spindle Hand Operated Charkha at 5500 rpm in Table-5.3, however
the SITRA norms are better probably because of better cottons are
152
used in the mills and latest spinning machinery are available in the
mills.
5.3.7 TOTAL IMPERFECTIONS/KM
The total imperfections are the sum total of thin place, thick
place and neps/Km of yarn. It goes to show the yarn defects in a
Kilometer of yarn length. From the table 5.3, the total imperfections of
33s Nm count shows 63.5 and 9.5 percentage improvement in 16
Spindle Improved Charkha when compared with 8 Spindle Hand
Operated and 8 Spindle Motor Operated Charkha respectively. The 8
Spindle Hand Operated Charkha shows higher values, because of
jerky rotation of fluted rollers and spindles and uneven twist of yarns.
However the SITRA norms are comparable with the results of 16
Spindle Improved Charkha. At the spindle speed of 6500 rpm, Table-
5.4 indicates 13.3 percentage improvement in 16 Spindle charkha
when compared with 8 spindle charkha.\
5.3.8 RKM VALUES
The RKM value of 16 Spindle Improved Charkha shows 26.4
percentage and 4.3 percentage improvement when compared with 8
Spindle Hand Operated Charkha and 8 Spindle Motor operated
Charkha respectively (Table-5.3). The RKM strength of yarn obtained
on 16 Spindle machines is equal to SITRA norms. There is a
marginal improvement at 6500 rpm also.
5.3.9 PERCENTAGE OF ELOMGATIONFrom the Table- 5.3, it is clear that the percentage of elongation
153
in 16 Spindle Improved Charkha shows 22.4 percentage decrease in
elongation when compared with 8 Spindie Hand Operated Charkha
and a decrease of 6 percentage improvement when compared with 8
Spindle Motor Operated Charkha. This marginal decrease in
elongation in the Table- 5.3 and 5.4 is due to use of poor cottons in
the handloom sector.
5.3.10 HAIRINESS INDEX
There is not much improvement in hairiness index in all the
machines when compared SITRA norms. The factors contributing to
hairiness in yarn are type of cotton used, processing parameters,
speed of machines; ring and traveller combination etc. if these items
are taken care of we can reduce hairiness.
5.4 Yarn Quality Characteristics Of 64sNm spun on
Charkha (5500 rpm and 6500 rpm)
5.4.1 64s Nm count were spun on the charkhas using 5500 rpm
and 6500 rpm of spindle speeds. The quality particulars of 64s Nm
count are obtained from 8 Spindle Hand Operated Charkha, 8
Spindle Motor Operated Charkha and 16 Spindle Improved Charkha
are compared with SITRA Norms.
The trial was taken on 8 Spindle Hand Operated Charkha,
8 Spindle Motor Operated Charkha, 16 Spindle Improved Charkha on
64s Nm at a constant speed of 5500 rpm (Table-5.5) and 6500 rpm
(Table-5.6). The yarn was tested for various parameters like CV% of
154
TPI, U%, Thin places/km, Thick places/km, Neps/km, Rkm values, %
of Elongation and Hairiness Index. Average of 20 readings for each
quality particulars is given in the table 5.5 and 5.6. The TPI given to
yarn was 26.0. It was kept constant for all the machines.
5.4.2 CV% of TPI
From the above table 5.5, it is evident that the CV% of TPI are
much higher in 8 Spindle Hand Operated Charkha, this is because of
irregular rotation of handle of the machine. But the 16 Spindle
Improved Charkha shows 36.4 percentage improvement when
compared to 8 Spindle Motor Operated Charkha at 5500 rpm. There
is also a 78.6 percentage improvement in CV% of TPI when
compared with Hand Operated Charkha.This is because there is a
uniform twist flow between the nip of the front roller and traveller
because of motorisation of charkha. At 6500 spindle speeds (Table -
5.6), there is 21.3 percentage improvement in the 16 spindle charkha
when compared with 8 Spindle Motorized Charkha. . .
5.4,3 U%
The U% of 8 Spindle Hand Operated Charkha shows higher
values than other two charkhas. There is a 27.5 percentage
improvement in U% in the 16 Spindle Improved Charkha when
compared with 8 Spindle Hand Operated Charkha in Table-5.5. The
achievement of U% results in the 16 Spindle Charkha are better than
the SITRA Norms at both the spindle speeds.
155
5.4.4 THIN PLACES/Km
This table 5.5 and 5.6 indicates the performance of thin places
(Yarn imperfections). There is a 80.5 percentage improvement in the
yarn imperfections in 16 Spindle Charkha when compared with the
results of 8 Spindle Hand Operated Charkha for 64s count. The 16
Spindle Charkha values comparable to SITRA norms. The 8 Spindle
Hand Operated Charkha shows higher values because of the
irregular motion of charkha and jerky rotation of fluted rollers. But the
16 Spindle Improved Charkha shows 8.2 percentage improvement
when compared with 8 Spindle Motor Operated Charkha. This is
because of smooth rotation of drafting rollers and no vibration in the
improved machine.
5.4.5 THICK PLACES/Km
This Table 5.5 and 5.6 indicates the performance of thick
places (Yarn imperfections) at speeds of 5500 rpm and 6500 rpm
respectively. There is a 50.0 percentage improvement in the yarn
imperfections (thick place) if we compare the performance of 16
Spindle Improved Charkha with 8 Spindle Hand Operated Charkha.
There is also a 8.0 percentage improvement in power operated 8
Spindle Charkha when compared with 8 Spindle Hand Operated
Charkha. The 16 Spindle Charkha has given equivalent better quality
than SITRA norms. At 6500 spindle speeds, there is 9.2 percentage
improvement in thick places in 16 Spindle Improved Charkha when
compared with 8 Spindle Motorised Charkha.
158
5.4.6 NEPS/Km
The neps in the do not have any significant contribution in
charkha spinning. As neps are contributed at the carding stage. The
neps per km of charkha yarn compare well with the SITRA norms.
5.4.7 TOTAL IMPERFECTIONS/Km
The table 5.5 and 5.6 indicates that the total imperfections of
64s count shows 49.3 percentage and 4.4 percentage improvement in
16 Spindle Improved Charkha when compared with 8 Spindle Hand
Operated and 8 Spindle Motor Operated Charkha respectively at
5500 rpm. At 6500 rpm the 16 Spindle Improved Charkha shows 7.8
percentage improvement in Total imperfections. The results of the 16
Spindle Improved Charkha compare well with SITRA norms.
5.4.8 RKM VALUES
Referring to Table - 5.5 and 5.6, the RKM value of 16 Spindle
Improved Charkha shows 68.9 percentage improvement when
compared with 8 Spindle Hand Operated Charkha and 9.2
percentage improvement at 5500 rpm and 4.3 percentage
improvement in 6500 rpm in yarn strength when compared with 8
Spindle Motor Operated Charkha. The RKM strength of yarn obtained
on 16 spindle machines is equal to SITRA norms.
5.4.9 PERCENTAGE OF ELONGATION
From the Tables -5.5 and 5.6, it is clear that the percentage of
elongation in 16 Spindle Improved Charkha shows 15.5 percentage
decrease when compared with 8 Spindle Hand Operated Charkha
and a decrease of 7.2 and 4.3 percentage when compared with 8
Spindle Motor Operated Charkhas in Table -5.5 and 5.6.
5.4.10 HAIRINESS INDEX
There is not much improvement in hairiness index in all the
machines when compared with SITRA Norms. The factors
contributing to hairiness in yarn are type of cotton used, processing
parameters, speed of machines; ring and traveller combination etc. if
these items are taken care of we can reduce hairiness.
5.5 Yarn Quality Characteristics Of 72s Nm spun on
Charkhas (5500 rpm and 6500 rpm)
5.6.1 72s Nm count was spun on the charkhas using 5500 rpm
and 6500 rpm of spindle speeds .The quality particulars of 72s Nm
count are obtained from 8 Spindle Hand Operated Charkha, 8
Spindle Motor Operated Charkha, and 16 Spindle Improved Charkha
are compared with SITRA norms. The TPI given to yarn was 28.0. It
was kept constant for all the machines.
The yarn was tested for various parameters like CV% of TPI, U%,
Thin places/km, Thick places/km, Neps/km, Total imperfections/Km,
Rkm values, Percentage of Elongation, and Hairiness Index. Average
of 20 readings are given for each quality particulars in the Tables -
5.7 and 5.8. •
160
5.5.2 CV % OF TPS
The Tables - 5.7 and 5.8, shows that the CV% of TPI are
much higher in 8 Spindle Hand Operated Charkha.This is because of
irregular rotation of handle of the machine. But the 16 Spindle
Improved Charkha shows 10 percentage improvement when
compared to 8 Spindle Motor Operated Charkha at 5500 rpm and 14
percentage improvement when the speed is increased to 6500 rpm
for 72s Nm count. There is also a 63.4 percentage improvement in
CV% of TPI when compared with Hand operated Charkha. This is
because there is a uniform twist flow between the nip of the front
roller and traveller because of motorization of charkha.
5.5.3 U %
The U% of 8 Spindle Hand Operated Charkha shows higher
values than other two charkhas. There is a 21.8 percentage
improvement in U% in the 16 Spindle Improved Charkha when
compared with 8 Spindle Hand Operated charkha at 5500 rpm and
5.6 percentage improvement at 6500 rpm for 72s count when
compared with 8 Spindle Motorised Charkha. The achievement of
U% results in the 16 Spindle Charkha are better than the SITRA
norms at both the speeds.
5.5.4 THIN PLACES/Km
The tables 5.7 and 5.8 indicate the performance of thin places
(Yarn imperfections). There is a 81,7 percentage improvement in the
163
yam imperfections (thin places) in the 16 Spindle Charkha when
compared with the results of 8 Spindle Hand Operated charkha. The
16 Spindle Charkha values comparable to SITRA norms. The 8
Spindle Hand Operated Charkha shows higher values because of the
irregular motion of charkha and jerky rotation of fluted rollers. But, the
16 Spindle Improved Charkha shows 16.3 percentage improvement
when compared with 8 Spindle Motor Operated Charkha, because of
smooth rotation of drafting rollers and no vibration in the improved
machine. When the speed is increased to 6500 rpm and compare the
yarn quality (thin places), it is found that there is 17.2 percentage
improvement in the new charkha.
5.5.5 THICK PLACES/Km
The tables - 5.7 and 5.8 indicate the performance of thick
places (Yarn imperfections). There is a 53 percentage improvement
in the yarn imperfections (thick place) when compared with the
performance of 16 Spindle Improved Charkha to 8 Spindle Hand
Operated Charkha (Table - 5.7). There is also a 48.3 percentage
improvement in power operated 8 Spindle Charkha when compared
with 8 Spindle Hand Operated Charkha. There is a slight deteoriation
in 16 Spindle Improved Charkha when compared to SITRA norms. At
6500 spindle speed the thick places show a reduction of 16.5
percentage in thick places in 16 Spindle Charkha.
5.5.6 NEPS/Km
The neps do not have any significant contribution in charkha
164
spinning. As neps are contributed at the carding stage. The neps per
km of charkha yarn compare well with the SITRA norms.
5,5.7 TOTAL IMPERFECTIONS/Km
From the Table - 5.7, the total imperfections of 72s Nm count
shows 53.4 percentage and 11.5 percentage improvement in 16
Spindle Improved Charkha when compared with 8 Spindle Hand
Operated and 8 Spindle motor Operated Charkha respectively. The
results of the 16 spindle improved charkha compare well with SITRA
norms. In the Table - 5.8 at 6500 rpm of spindle speed there is a
reduction of 14.1 percentage in the total imperfections in the yarn that
is spun on the 16 Spindle Charkha. Even at such high speeds the
total yarn imperfections obtained on the new charkha are comparable
with SITRA norms.
5.5.8 RKM VALUES
The RKM value of 16 Spindle Improved Charkha shows 19
percentage improvement when compared with 8 Spindle Hand
Operated Charkha and 2 percentage improvement in yarn strength
when compared with 8 Spindle Motor Operated Charkha (Table-5.7).
The RKM strength of yarn obtained on 16 Spindle machine is equal to
SITRA norms. At higher speeds of 6500 rpm (Table - 5.8), the RKM
strength obtained on the 16 Spindle Charkha is comparable to SITRA
norms This proves the hypothesis that better yarn quality can be
produced on 16 Spindle Improved Charkha.
5,5.9 PERCENTAGE OF ELONGATION.
From the Tables - 5.7 and 5.8, it is clear that the percentage of
elongation in 16 Spindle Improved Charkha shows 32.1 percentage
decrease in elongation when compared with 8 Spindle Hand
Operated Charkha and a decrease of 3.6 percentage when compared
with 8 Spindle Motor Operated Charkha at 5500 rpm. Similarly there
is a 18.5 percentage decrease in elongation in the 16 Spindle
Charkha at 6500 rpm when compared with 8 Spindle Motorised
Charkha.\
5.5.10 HAIRINESS INDEX
There is not much improvement in hairiness index in all the
machines when compared with SITRA norms. The factors
contributing to hariness in yarn are type of cotton used, processing
parameters, speed of machines; ring and traveller combination etc if
these items are taken care of we can reduce hairiness.
5.10 Ratings For Yarn Appearance Using ASTM Boards
Count SITRA Norms Actual Ratings
Achieved
20's to 100’s Carded D D
Counts
Yams samples taken from 16 Spindle Charkha wrapped on
ASTM Boards and compared with SITRA norms. The findings are
comparable to the mill yarns in both appearance and quality.
166
This proves the hypothesis that the yarn quality and yarn
appearance of yarns produced on the 16 Spindle Improved Charkha
is comparable to the yarns that are produced in the textile mills the
counts being similar. The new charkha that has been developed
produce yarns in all counts ranges with comparable yarn quality. With
spindle speeds beyond 6500 rpm it was found that the thread
breakage was higher resulting in lot of time waste in repairing the
broken threads. This resulted in loss of machine efficiency. The
reason for excessive thread breaks was due to poor quality roving
used. More trials with better quality roving and at higher spindle
speeds could be tried out. Generally higher spindle speeds, gives
higher productivity and even better wage earnings.
SUMMARY
The applicability and use of any yarn will be determined by the
quality of it. General yarn quality parameters that any buyer will look
for will be count, TPI, CV% of TPI, U%, Thin places/Km, Thick
places/Km, Neps/Km, Total imperfections/Km, Rkm values (Gms/
tex), Elongation percentage and Hairiness index etc. The above
parameters were evaluated with the yarns produced in three
charkhas namely 8 Spindle Hand Operated Charkha, 8 Spindle Motor
Operated Charkha and 16 Spindle Improved Charkha for different
counts ie 10s Nm, 33s Nm, 64s Nm, 72s Nm. In all the above counts of
yarn, it has been observed that improvements in the quality
parameters were established and some of the parameters were on
par with SITRA norms for yam quality. The yarn appearance ASTM
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standard has been complied by the yarn produced in the improved
design charkha. The SITRA Norms are for the yarns made in the mill
spinning. But in the present work, 8 Spindle Motor Operated Charkha,
16" Spindle Improved Charkha has yielded improved quality yarns
proving way for its adoption and commercial sales.
Thus the hypothesis stating that by incorporating the improved
design of the charkha, the quality parameters of the output yarn has
been improved in terms of CV% of TPI, U%, Thin places/Km, Thick
Places/Km, Total imperfections, Rkm Values, Percentage of
Elongation and Hairiness index has also been proved.
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