Indian Journal of Textile Research

Vol. 4, June 1979, pp. 63-70

Detailed Analysis of Carding Quality and Its Influence on Processing and Yarn
Properties
S K NERURKAR-
The Bombay Textile Research Association, Bombay 400086
Received 17 June 1978; accepted 22 April 1979

Detailed analysis of card web/sliver and other post-card products has been done for obtaining improved understanding
about the changes in the characteristics of card web/sliver with carding quality and the impact of carding quality on the pro-
perties of yarn spun on different spinning systems. The analysis has shown that although the routine tests of carding quality
such as trash in sliver, neps in card web, cylinder load, etc. assist in grading carding quality, other card web characteristics such
as evenness in card web weight per unit area, short term variation in sliver thickness, fibre parallelization, fibre to fibre
separation are also important parameters of card web contributing to carding quality. Although bad carding gives better
parallelization, the rate of improvement in parallelization in the subsequent processes is better with good carding, probably due
to better fibre separation. Fibre separation seems to influence carding quality more than fibre parallelization. The size of trash
particles does not change much with carding condition. Open end spinning has been found to be more sensitive to carding
condition both for performance and yam quality than ring spinning. These findings suggest that by carding material under
adverse conditions many carding quality characteristics other than the routine ones get changed and the influence on spinning
performance and yarn quality depends on the spinning system used.

Although the influence of carding quality on post- discovery of hooks in card web by Morton and
carding processes and yarn quality is well accepted, the Summer", hook measurement and configuration of
term 'carding quality' has not been defined precisely. fibres in a sliver were studied by several workers.
This is due to incomplete understanding about the Simpson and Fiori8 found that both hooks and fibre
different measurements required to fully describe parallelization must be measured to characterize the
carding quality and also due to many non-measurable card sliver and processing performance. The concept of
characteristics of card web in a routine manner. The card loading was developed by Kaufmann", while
need to have a more detailed understanding for carding Krylov'? devised a simple method for measuring
quality is now felt due to the phenomenal increase in transfer efficiency. These different parameters of
production rate of card, when carding quality becomes carding quality did not seem to encompass all the
critical at such rate, and also due to the advent of many determinants of carding quality.
new spinning systems in recent years which may Although the routine tests of card web such as neps,
require different configurations of fibres in a sliver than trash particles and cleaning efficiency help to grade the
for ring spinning for better performance. Recently, carding quality to some extent, and the same were
Ashnin 1 developed a high speed method for assessing emphasized more in the past, not much information is
web quality, while Sundra and Swiech" tried to relate available as to how with the deterioration in carding
the purity of card web to yarn properties. Ul'man" tried quality evenness in card web weight per unit area, short
to evaluate card web quality by counting the number of and long term variation in sliver thickness, fibre
holes containing neps on the web deposited on the separation and fibre paralle1ization, etc. are affected at
plate. Barella and colleaguest-" developed an card stage and also at subsequent stages. In an attempt
electronic instrument for measuring the unevenness to get a better understanding of the subject of carding
and neps in card web, while Jackowski" measured fibre quality, card web and its post-card products obtained
distribution across the flat carding surface. After the under widely different carding conditions have been
examined in detail. The changes in different
characteristics of card web/sliver due to carding
-This work was carried out by the author at the Southern
conditions have also been examined and their influence
Regional Research Center of United States Department of
Agriculture at New Orleans, USA, while pursuing the fellowship on spinning and yarn quality has been studied. It is
sponsored by the World Association of Industrial & Technological envisaged that this approach may help in improving
Research Organisation, Vancouver, Canada. understanding of carding quality to some extent,

63
 INDIAN J. TEXT. RES., VOL. 4, JUNE 1979

although it may not suggest any new definition of spindle hours for each count. As the hank of card sliver
carding quality. was different for the two carding conditions, the same
was adjusted to a common hank of 0.16 Ne in two post-
Experimental Procedure card drawing passages in steps.
Blowroom laps of 140z/yd made from two The part of the material after the second drawing
American cottons, Middling (clean) and Low Middling was spun on Toyoda OE spinning with 5.19 and
(dirty), were processed on Whitin metallic card with a 5.23 TM for 12/1 and 24/1 counts respectively, and at
Crosrol doffer take off and crush roll attachment under 34,000 rpm rotor speed and 6000 rpm opening roll
two different carding conditions. The fibre properties speed. End breakage study on OE spinning was
ofthe cottons are given in Tablel. The card particulars conducted on 20 rotors and for 80 spindle hours.
are given in Table 2. The card sliver was given two The fibre and yarn properties were determined by
passages of drawings, then processed on roving and methods recommended by the American Society for
two carded counts, i.e. 12/1 and 24/1, were spun on Testing and Materials 11. Sliver uniformity was tested
Robberts ring frame with 4.2 TM and at 9100 and on the Saco-Lowell sliver thickness tester converted to
12000 (rpm) spindle speed respectively, on 2.25 in electrical recordings 12. The 'between length' measure

diameter ring. The ringframe used was with 240 was 1 in and the 'within length' measure was 1 yd. The
spindles and end breakage study was conducted for 720 CV% of 20 one-yard samples was averaged for a test.
Sliver and roving evenness and yarn imperfections and
uniformity were measured on Uster II evenness tester
Table I-Fibre Properties at standard recommended speeds for the respective
materials.
Middling Low Middling Fibre hooks were measured by cutting ratio and
Length fibre parallelization by projected mean length on
Classer's, in 1-3/32 1-1/16 SRRL triple clamp instrument'". The sizes of dust
particles were measured using a Coulter counter. The
Digital jibrograph
2.5% span length, in 1.08 1.06 percentage card waste was calculated by processing
50% do 0.47 0.46 200 lb of lap cotton for each trial. Five readings of
Uniformity ratio 43 43 cylinder load, flat load and transfer efficiency, equally
Micronaire reading 4.60 4.60 spaced in the entire duration of trial, were taken for
each trial. Transfer efficiency and cylinder load were
Stelometer
Zero gauge, g/tex 40.3 41.8 measured by Krylov method 10, while flat load was
1/8 in gauge, g/tex 22.6 23.0 estimated by actual weighing of the flat strips from 15
Elongation, % 8.43 7.28 flats removed by flat comb during normal working.
The number of neps and trash particles was counted by
Shirley analyzer
Trash, % 0.82 2.87
template method. For each trial, 36 readings were
taken for nep and trash study. The variation in weight
of card web per unit area was calculated by weighing 40
Table 2-Card Processing 'Particulars for Good and Bad web pieces of 4 x 4 in size. This was done by
Carding Condition sandwiching the card web at the front of cros-rol of
card, between a pair of plastic sheets of appropriate
Carding condition
size.
Good Bad
Speed and production parti-
culars on card
Results and Discussion
Hank of blowroom lap fed to card 0.00136 0.00136 Card waste study-The results of card waste study
_Licker in, rpm 745 450 given in Table 3 show that under bad carding
Cylinder, rpm 300 185 condition less waste is removed than under good
DolTer, rpm 20.8 25.8
carding condition. This has resulted in poor cleaning at
Flats, in/min 5.5 0.875
Hank of card sliver 0.167 O.lll card under bad carding condition, as seen from the
Total mechanical draft at"card 122.4 81.6 lower cleaning efficiency.
Grains per yard of card sliver 50.0 75.0 N ep count and variation in weight of card web per unit
Production rate at card, lb/hr 30.0 56.0 area-The numbers of neps and trash particles in card
web and CV% in weight of card web per unit area are
Card settings
Flat to cylinder, 0.001 in 10 34
given in Table 4. Under bad carding condition, higher
All other settings Normal Normal numbers of neps and trash particles are obtained at
card stage with both the cottons. Variation in weight of

64
 NERURKAR: CARDING QUALITY & ITS INFLUENCE ON PROCESSING & YARN PROPERTIES

card stage due to carding condition got narrowed

Table 3-Percentage of Card Waste and Cleaning Efficiency down as the rate of improvement of parallelization in
of Card at Different Carding Conditions the subsequent process was higher with good carding,
possibly due to better fibre to fibre separation
Middling Low Middling (obtained with good carding) and lower degree of
(clean) (dirty)
parallelization obtained with good carding. However,
Carding condition Good Bad Good Bad
SlIVER
__ i':
Total visible w-aste, % 1.76 0.54 2.57 1.08
.s
C!J' -2 ~1l0RAWING
~ 75XI0
Break-up of waste, % ~ in KEY
(a) Licker-in droppings 0.33 0.19 1.10 0.62 a: ----CLEAN COTTON
1.43 0.35 1.47 0.46 CII --OIRTY COTTON
(b) Flat strips
a:
Cleaning efficiency of card, % 72.5 29.7 83.8 41.1 w
>
:::;
VI

~
Table 4-Nep and Trash Level in Card Web and Variation VI
w
a:
in Card Web Weight Per Unit Area m
ii: 2
1L60XU) -
o in
Middling LowMiddling •...
X
t!)
(clean) (dirty) Z
w
-'
z 0--------<>
Carding condition Good Bad Good Bad cl
ROVING
4.4
'"2 _--0
Neps/grain in card sliver 10.3 4.0 6.1 Q 0--
No. of trash particles/grain 2.2 3.3 3.0 3.7 •...
w
u
in card sliver '"6
Coefficient of variation (%) in 14.5 16.4 19.2 29.1 a:
0.. -2
card web weight of 4 x 4 in size
45i~IO LG;;;OOO:6:;;;:-----;B~AO~---::G:;::O""OO;::------::B:-I:~'::'D--::I75X 102
CARDING CONDITION In

web per unit area was found to be high under bad Fig. I-Effect of carding conditions on projected mean length of
carding condition for both the cottons. This difference fibres in card sliver, I and II drawing sliver and roving
in CV% of the weight of card web per unit area arising 0'10 9 r---:-A-::D~O:::T'--I~N~D-::IC:-:AT=:E:-::S:-::B7AD=-::CA~RD:-::I:-:NG::-:-WH=IL-::E:-----'
due to carding condition was more with dirty cotton 'NO DOT'INDICATES GOOD CARDING
than with clean cotton. The differences in CV% due to
carding conditions was significant only in dirty cotton. --CLEAN COTTON--- --DIRTY COTTON----

The finding of high CV% under bad carding condition ~I

was also supported by high short term variation in II
II
sliver thickness as measured on Saco-lowell tester, ~,
which is discussed later. However, since the card web is \
\ MAJORITY HOOK
folded to form a sliver, the differences in CV% of web
weight per unit area arising due to carding condition
diminish while measuring the variation in the thickness
V
1\
II
II
of card sliver at 1 in length (Tables 4 and 6). 1\
II
Measurement of hooks and fibre parallelization in II
card, drawing sliver and roving-The values
of I~
projected mean length and cutting ratio obtained for
card sliver and I and II drawing sliver and roving are
.~
hI
1\

plotted in Figs. 1 and 2. It is evident from Fig. 1that the " 1\

projected mean length of fibres in sliver and roving "II

II
which measures the degree ofparallelization of fibres in II
\I
sliver and roving was higher under bad carding I 'x.
I
conditions at all stages from card I drawing, II drawing X

and roving, as seen by higher values of PML with bad

carding. The values of PML with bad carding were
0·009 CARD
much higher than those with good carding at card
stage and subsequently as the sliver was processed Fig. 2-Effect of carding conditions on majority and minority hooks
through drawing and roving, this difference in PML at at card and I and II drawings

65
 INDIAN J. TEXT. RES., VOL. 4, JUNE 1979

Another effect of increased relative speed of dofTer

- - - CLEAN COTTON was reduction in majority hooks and increase in
-- DIRTY COTTON minority hooks at card stage with bad carding'?
0----0 GOOD CARDING
(Fig. 2). It is seen from Fig. 2 that majority hooks are
~ BAD CARDING
more under good carding than under bad carding con-
dition, at card stage and this trend continues up to I
~ drawing and II drawing in most ofthe cases. Similarly,
II
/I minority hooks are more under bad carding than with
1/ good carding condition, at card stage; this trend
II
continues up to I drawing and II drawing. So the
o II
.., II peculiar pattern of hooks observed at card stage due to
, 1/ carding condition continues up to II drawing stage.
R\ /I This indicates that the rate of unhooking the hooked

.'\J.:
\ , 1/
, ,II fibre during drafting, at drawing, remains same
\' ,\
irrespective of the carding conditions under which
hooks are formed.
,\
Cylinder and flat load, and transfer efficiency-The
values of cylinder load, flat load and transfer efficiency
of card given in Table 5 show that for any given cotton,
bad carding condition reduces transfer efficiency and
1 11 I 11
consequently increases the cylinder load. However, the
1 DRAWING TOTAL DRAWING TOTAL
CLEAN COTTON DIRTY COTTON increase in flat load due to bad carding conditions is
much less than the corresponding increase in cylinder
Fig. 3- EIT~t of carding conditions on the rate of improvement in
parallelization of fibres at I and II drawing process
load.
Sliver evenness at card, drawing and roving-The
it is worth noting from Fig. 1 that this difference in values of evenness of card sliver, I and II drawing sliver
PML never vanishes completely even up to roving. The and roving are given in Table 6. It is evident that at
rate of improvement of parallelization at passage I and card stage, short term variation in sliver thickness as
II of drawing and the total rate of improvement of the measured by Saco-Lowell tester is higher under bad
parallelization for the two drawings together are given carding condition than under good carding condition.
in Fig. 3 which shows higher rate of improvement in This short term variation in sliver thickness increases
parallelization when the sliver was obtained from good from card to II drawing continuously and hence at II
carding. drawing also, bad carding has shown more unevenness
The better parallelization of fibres under bad than that obtained under good carding condition. In
carding condition at card stage can be explained as other words, the variation in thickness in sliver
follows. observed at card due to carding condition increases
For bad carding condition, cylinder speed was continuously up to II drawing. For a given cotton, the
reduced from 300 to 185 rpm, while dofTer speed was difference in CV% in sliver thickness at every 1 in
increased from 20.8 to 25.8 rpm. These two length arising due to carding condition was found to be
simultaneous changes in cylinder and dofTer speed statistically significant at card, I drawing and II
have increased the relative speed of dofTerwith respect drawing stages for both the cottons, except for clean
to cylinder at the cylinder-dofTer transfer point which cotton at I drawing stage.
might have resulted in improved parallelization of In case ofJong term variation, as measured on Saco-
fibres during its transfer to dofTer. Lowell thickness tester, no specific trend was found

Table 5-Cylinder Load, Flat Load and Transfer Efficiency of Card at Good and Bad Carding Conditions

Good Carding Bad Carding

Type of cotton Cylinder Flat load of Transfer Cylinder Flat load of Transfer
used load 15 Oats efficiency load 15 Oats efficiency
gr gr % gr gr %
Clean cotton 114.6 139.2 10.2 384.7 331.8 9.2
Dirty cotton 115.7 168.7 10.1 443.7 419.6 7.9

66
 NE~URKAR: CARDING QUALITY & ITS INFLUENCE ON PROCESSING & YARN PROPERTIES

Table 6-Evenness of Card and Drawing Sliver and Roving

Description Uster Saco-Lowell Uster Saco-Lowell Uster Saco- Lowell Uster

of material evenness tester evenness tester evenness tester evenness
tested tester tester tester tester
U% Short term Long term U% Short term Long term U% Short term Long term U%
variation* variationt variation variation variation variation
Clean cotton
good carding 4.39 2.57 3.06 3.91 4.28 0.64 4.08 4.41 0.96 6.86
condition

Clean cotton
bad carding 3.22 2.91 2.64 3.10 4.39 0.96 3.95 5.23 1.16 7.81
condition

Dirty cotton
good carding 4.40 2.45 2.54 3.34 4.28 0.60 4.23 4.51S 0.91 7.12
condition
Dirty cotton
bad carding 7.31 2.92 4.77 3.21 4.67 0.87 4.18 5.07 1.11 8.03
condition
*Coefficient of variation (%)of sliver thickness at every 1 in length, scanned for 20 yards. As the hank of card sliver for good and bad carding
is different the C.Vs. are corrected and standardized to SO gjyd sliver weight for short and long term length.
tCoeff.'Cient of variation (%) of sliver thickness between every I yard length of sliver.

between good and bad carding at card stage and Saco-Lowell tester is influenced by variation between
whatever differences were there at card stage are 7 in length of blow room lap fed to card and also by
levelled up, up to II drawing stage due to the number of carding condition under which it is processed, and
doublings the sliver undergoes in the drawing process. hence no specific trend of carding condition alone
It is worth noting here that although for short length of could be seen in it. The data in Table 6 also show that
sliver (1 in), Saco-Lowell tester has shown some roving from good carding was more even than that
specific trends reflecting upon the carding condition with bad carding.
under which the lap was processed, no such trend was Analysis of size of trash particles collected in rotor in
seen in the results obtained from Uster It evenness open end (0 E) spinning- The trash collected from the
tester. This is because the speed of sliver while testing rotor in OE spinning was analyzed for its average
on Uster evenness tester was 25 yd/min and every particle size and number of trash particles of each size
reading was taken at 5 min intervals and hence one using the Coulter counter. The weighted average size of
reading corresponds to 125 yards of sliver. Taking into trash particles was around 4~25-4.44Jl and the volume
account the draft at card of about 100 or so, it will be of trash particle was around 13-16 Jl3.
seen that the reading at Uster evenness tester is influ- Effect of carding condition on amount of trash
enced both by yard to yard variation in blow room released on rotor ofOE spinning-To study the effect of
lap fed to card and also by the card condition at which carding condition on the quantity of trash released in
it is processed. Hence, no clear-cut trends relating the rotor of OE spinning, the actual trash released in
carding condition alone to Uster evenness reading the rotor was collected, weighed and expressed as mg/
could be seen. On the other hand, thickness variation kg yarn spun under good and bad carding conditions.
for short length (1 in) as measured by Saco-Lowell The results are given in Table 7. It is seen that with
sliver tester, measures only the thickness of sliver once both clean and dirty cottons, the quantity of trash in
in every inch of sliver and thus a 36 in length of sliver is the input sliver increases under bad carding condition.
scanned. In case of long term variation as measured by And when the quantity of trash in the input sliver
Saco-Lowell tester, the thickness of sliver is averaged increases, that of trash released in the rotor also
over 36 in length of sliver and then 20 yards length of increases. This increased quantity of trash in the rotor
sliver is scanned and CV% is calculated for short and leads to higher breakage rate and at times even makes
long term variations. So, short-term CV% in sliver spinning difficult unless the machine is stopped and the
thickness as measured by Saco-Lowell tester is not rotors are cleaned. This shows that for satisfactory
much affected by variation in blowroom lap, while the performance at OE spinning, the level of trash in the
long term CV% in sliver thickness as measured by input sliver should be kept to the minimum. From

67
 INDIAN J. TEXT. RES., VOL. 4, JUNE 1979

Table 7, it is also seen that when the count gets finer, on ring and open end spinning frame for two counts 12/
with identical carding condition and cotton, the 1 and 24/1 given in Table 8 show that the end breakage
quantity of trash released in the rotor increases rate increased under bad carding condition for both
markedly. This indicates that for spinning finer counts the counts and for both the spinning systems. However,
emphasis on cleaned cotton sliver at card should be with any given spinning system, the increase in
more than that for spinning relatively coarser count on breakage rate due to bad carding condition was more
OE spinning. with fine count. Between the two spinning systems, for
Performance of yarn at ring and open end spinning any given count, the increase in end breakage rate was
frame-- The results of end breakage studies conducted more with OE spinning than with ring spinning. The

Table 7-Quantity of Trash Collected in Rotor of OE Spinning System for Different Carding Conditions

Type of Carding Count Duration of Total wt Trash in the Wt of trash Wt of trash

cotton condition spun spinning of yarn input sliver collected collected
used hr produced mgJkg of in rotor in rotor
kg sliver mg mg/kg of
yarn spun
Clean Good 12/1 4.00 11.200 720 12.1 1.08
Clean Good 24/1 3.17 3.176 720 16.7 4.44
Clean Bad 12/1 4.00 11.200 1792 2690.8 240.25
Clean Bad 24/1 4.00 4.012 1792 1098.0 273.68
Dirty Good 12/1 4.00 11.200 1057 91.9 8.21
Dirty Good 24/1 4.00 4.012 1057 70.5 17.57
Dirty Bad 12/1 4.00 11.200 4916 12934.8 1154.89
Dirty Bad 24/1 1.75 1.760 4916 2083.4 1186.95

Table 8-End Breakage Rate and Physical Properties of Ring Spun and Open End Yarn
Ring Yarn Open End Yarn

Clean cotton Dirty cotton Clean cotton Dirty cotton

Good Bad Good Bad Good Bad Good Bad

carding carding carding carding carding carding carding carding
(Count 12/1)

End breakage rate

Breaks per 1000 spindle hours 41.7 66.2· 29.7 79.8* 12.5 87.5 12.5 212.5
Lea tests
Count strength (lb) product 2391 2300 2327 2287 2036 1623 2015 1455
Single thread tests
Single thread strength, g 763.5 771.0 768.0 756.0 599.3 490.5 622.5 471.0
Elongation, % 9.8 9.75 8.50 8.60 9.30 8.60 8.45 7.40
Uster evenness, U% 13.37 15.14 13.59 15.35 11.74 15,08 12.15 16.42
Thin places per 1000 yd ( - 50%) 1 8 2 13 0 39 5 186
Thick places per 1000 yd ( + 3) 84 294 89 352 20 121 31 239
Neps per 1000 yd ( + 3) 18 151 21 212 28 377 49 332

(Count 24/1)
End breakage rate
Breaks per 1000 spindle hours 43.1 94.6· 46.0 190.6* 15.8t 287.5 75.0 8oo.0t
Lea tests
Count strength (lb) product 2138 2103 2155 2086 1694 1394 1669 1337
Single thread tests
Single thread strength, g 340.8 319.2 340.8 320.4 255.0 232.8 259.2 211.2
Elongation, % 8.2 7.7 7.15 6.95 8.2 7.6 7.3 6.4
Uster evenness, U% 17.7 20.46 17.7 20.27 13.43 16.42 13.39 16.58
Thin places per 1000 yd ( - 50"1.) 104 253 106 236 14 127 23 186
Thick places per 1000 yd ( + 3) 653 1573 599 1416 50 283 86 369
Neps per 1000 yd (+3) 116 956 121 843 123 977 198 881
*740 spindle hour test. t63.3 spindle hours test. tJ5.0 spindle hour test.

68
 NERURKAR: CARDING QUALITY & ITS INFLUENCE ON PROCESSING s. YARN PROPERTIES

high end breakage rate in OE spinning with bad still the performance at spinning with both the
carding may be due to the high level of trash in the spinning systems and also the yarn quality in terms of
input sliver and so in the rotor (Table 7), and also due strength, evenness, thin places and thick places was
to insufficient separation of fibres due to bad carding. better with good carding. This indicates that fibre to
Physical properties of yarn- The physical properties fibre separation (which is better with good carding)
of yarns spun on ring and open end spinning frames are contributes more towards the yarn quality and ring
given in Table 8. It is evident that the count-strength frame performance than fibre parallelization (which
product (obtained from lea strength) decreases slightly was better with bad carding). This suggests that while
under bad carding condition, in-ring spun yarn, but assessing carding quality along with the routine card
drops markedly in open end yarn, for both the counts sliver characteristics other card web/sliver parameters
spun. The bad carding condition has not led to high like variation in weight of card web per unit area,
count variation (data not given in Table 8) at yarn variation in sliver thickness (1 in length), fibre
stage with both spinning. systems, although the short parallelization can be incorporated for getting a better
term variation in sliver thickness (Saco-Lowell) was understanding of carding quality over and above the
affected by carding conditions, as seen earlier, at card present determinants of card web.
and drawing stage. As regards single thread strength,
there is no consistent drop in strength with bad Conclusions
carding. The same can be said about yarn elongation. (1) Bad carding condition gives lower card waste,
The yarn evenness as measured by Uster II evenness poor cleaning efficiency at card, higher neps in card
tester (U%) was markedly poor under bad carding sliver, higher weight variation in web (weight of card
condition with both the spinning systems. But web per unit area) and higher short term CV% in sliver
deterioration in evenness (U%) due to bad carding was thickness measured at every 1 in length (as measured
more in OE yarn than in ring spun yarn for 'any given by Saco-Lowell thickness tester),
cotton. The same trend was seen only in the number of (2) The increased doffer speed under bad carding
thin places per 1000 yards with 12s/1 count. The condition causes reduction in the majority hooks and
number of neps increased under bad carding condition increase in the minority hooks. This peculiar pattern of
in both the spinning systems. hooks observed at card stage continued up to II
dra wing in most of the cases as the rate of unhooking of
Discussion hooked fibres during drafting was not affected by
This study has brought out that the carding carding condition at which hooks are formed.
condition affects not only the routine and known (3) Bad carding condition gives longer projected
characteristics of web/sliver such as neps, trash, hook mean length (PML) for card sliver, which indicates
pattern at card, but also weight variation in card web, better fibre parallelization under bad carding
% improvement in fibre parallelization obtained in condition. This is explained as being due to the higher
subsequent drafting after carding, variation in sliver relative speed of doffer with respect to cylinder, at
thickness between 1 in length of sliver and also fibre to cylinder-doffer transfer point. However, the rate of
fibre separation and fibre parallelization. The higher improvement in fibre parallelization in subsequent
variation in the weight of card web per unit area drawings was higher with good carding and hence the
observed with bad carding was measured directly and differences in PML at card stage due to carding
was also supported by high short-term variation in the condition were reduced when the sliver was processed
thickness-at card, I and II drawing sliver as measured at through drawing and roving. This high rate of
every inch, on Saco-Lowell thickness tester. the higher improvement in fibre parallelization in drawing and
rate of improvement in fibre parallelization with good roving can be possibly due to the better fibre to fibre
carding was confirmed by the improvement in the separation obtained under good carding condition and
percentage increase in the projected mean length at also due to the initial lower degree of parallelization
different stages of drawing and also at roving. obtained under good carding condition.
Although the better fibre to fibre separation with good (4) Under good carding condition, cylinder and flat
carding could not be measured directly, the same can load were lower, while the transfer efficiency was higher
be inferred from the better evenness obtained at roving. than that under bad carding condition.
It is also interesting to note that at card stage, fibre- (5) The thickness variation of sliver (Saco-Lowell) of
parallelization was poor with goo_d carding and short term nature (1 in) was found to be higher under
although it improved rapidly in subsequent drawing, bad carding condition; this trend continued up to II
probably due to the better fibre separation obtained drawing stage. The variation of long-term nature
with good carding, it was not better than that at bad (between 1 yard specimens) did not show any clearcut
carding even up to the II drawing and roving stage. But trends relating to carding conditions. -

69
 INDIAN J. TEXT. RES., VOL. 4, JUNE 1979

(6) Evenness of roving as measured by Uster area, vanation in sliver thickness and fibre
evenness tester was found to be better for the roving parallelization can be taken into account while
obtained from good carding. detailing the quality of carding.
(7) The average size of trash particles collected in
rotor of 0E spinning did not show much change in size Acknowledgement
with carding conditions. However, as the type of trash The author is thankful to the staff of the Cotton
varies widely with the area and picking methods, etc. Textile Processing Division of SRRC of USDA, New
further work will be required to confirm this finding. Orleans, USA, for helpful consultations and excellent
(8) Bad carding condition released more quantity of cooperation extended in the course of work in their
trash in rotor of OE spinning and this affected the end laboratory and to Dr N Balasubramanian for useful
breakage rate markedly in OE spinning. With a given discussion in interpreting some of the data and to Shri
back material, the quantity of trash released in the T V Ananthan, Director, BTRA, for permission to
rotor increased with the fineness of count. publish this work.
(9) The end breakage rate was higher under bad
carding condition on the two spinning systems tried, References
but the difference in end breakage rate due to carding 1 Ashnin N M, Technol Text lnd, USSR, No.4 (1972) 37-41.
condition was more with OE spinning system than that 2 Sundra A & Swiech T, Tech Wlok, 21(5) (1972) 136-42.
with ring spinning. This indicates that the OE spinning 3 Ul'man Z V, Te/<stProm, 22(5) (1962) 39-41.
system was more sensitive to carding condition. 4 Barella A et al., Text Res J, 32 (1962) 428-30.
5 Barella A et al., Text Res J, 33 (1963) 411-16.
(10)The count variation did not show any trend with 6 Jackowski T & Pyziak T, Przegl wlok, 26(4/5) (1972) 237-40.
carding condition; however, the yarn evenness (U%) 7 Morton W E & Summer R J, J Text Inst, 40 (1949) 106-16.
was poor with bad carding on both the spinning 8 Simpson J & Fiori L A, Premier Symposium International de la
systems. The influence of carding condition on yarn Recherche Textile Cotonnie're, Paris (Institut Textile De
evenness was more pronounced in OE spinning system France, Aboidances, 92 Boulogne SISeine, Paris) 1969,229-
48.
than in ring spinning system. The same trend of results 9 Kaufmann D, Text Prax, 12(11) (1957) 1077-82.
was also observed only in thin places with 12s/1 count. 10 Krylov V V, Technol Text lnd, USSR, No.2 (1962) 46-53.
(11) The level of neps in yarn increased under bad 11 ASTM Designation: D 2255-64, D 1440-65, D 1446-66T, D 1425-
carding conditions in both the spinning systems. 67, D 1445-67, D 144,7-67,D1578-67, D 1769-67, D 1448-68,D
(12) Detailed analysis of card web and sliver made 2256-69, D 1442-70 and D 2812-70 (American Society for
Testing and Materials, Committee D-13, Philadelphia,
here showed that apart from routine measurements Pennsylvania, 1970, 24 and 25.
such as trash in sliver, neps in card web, cylinder 12 Rusca B A, Text Res J, 20 (1950) 780-86.
loading, transfer efficiency, other card web/sliver 13 Simpson J & Patureau M A, Text Res J, 40 (1970) 956-57.
parameters like variation in weight of card web per unit 14 Simpson J, Deluca L B & Fiori L A, Text ResJ, 37 (1967) 504-9.

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