,IndianJournalofFibre& TextileResearchVol.19, December1994, pp,239-246

Optimization of ring frame parameters for coarser preparatory

S M Ishtiaque& Atal VijayDepartmentof TextileTechnology,Indian Instituteof Technology,NewDelhi 1\0 016, India

Received27 April 1993; revisedreceivedII April 1994; accepted23 May 1994

The intluenceof lap hank and card draft on cleaningefficiency,neps/g and fibredisorder in sliverhas beenstudied. The possibility of using coarser preparatory to produce good quality yarn by optimizing the speedframe and ring frame parameters has also been studied. The proportion ofcurved fibreends and coefficientofrelativefibreparallelization in sliverdecreasewith the increasein lap weightand decreasein card draft. Yarnsmade from coarse hanks at preparatory stages using optimum spinning parameters are comparable to millyarn and meet the ATIRA norms.

Keywords: Back roller setting, Break draft, Fibre disorder, Spacer size, Spinning, Top roller pressure

I IntroductionDuring the last twenty five years, marked

improvements have been made in the spinningtechniques, technology and machines. The intro-duction of multiple blender and improved scutcherhopper resultedin improvement in lap regularity.The greatest production increase has been obtainedin short-staple carding as compared to the traditionalmethods. It is in this process that most importantfundamental developments have taken placerecently, particularly in card feeding, webcondensing and fibre orientation at card whichformed the basis of new developments in comber-lappreparation and general carding practice. A betterunderstanding of the multiple sliver draftingrequirement resulted in lowering the number ofdrawframe passages.

It is known that the current state of quality andproduction technology in the preparation of rovingbobbins and their effect on ring spinning per-formance. have reached a high degree of development,and a significant increase in production rate will beachieved only by the use of much heavier strands. Thisis because higher roving frame speeds are restrictedprimarily by the mechanical limitation of flyer designand by technological limitations which aredominated by package building problems. Afterconsidering these limitations, the solution can beachieved only by using much heavier strands. But thiswiII depend on ring frame drafting developmentsrather than on improvements in the roving process.

Earlier, low drafts were employed at ring framesbut the significant developments in ring framedrafting system have introduced high draft at ring

frame. Now the question arises whether we are fullyexploiting the above-mentioned developments intopractice or not? The answer is, definitely not. Becauseif we look at the draft range on ring frame, it is stilltowards the lower side in comparison to that usedabroad. The use of low draft at ring frame meansrequirement of more preparatory machines, andhence more capital cost. To keep this particularproblem in mind, an attempt has been made in thepresent work to study the effect of coarse prepara toryon yarn quality by using higher draft at ring frame.

2 Materials and Methods2.1 Materials

Cotton mixing having F-414 and 1-34 cottons inthe ratio 80:20 and the following specifications wasused:

Fineness, 3.9 MicronaireBundle strength (at 1/8 in gauge length). 21 g/texMean fibre length, 26.30 mmEffective fibre length. 30.32 mmTrash, 3.4%

2.2 Sample PreparationThe laps of three different hanks were produced in

blow room from the above mixing and then processedon the same card under identical conditions. In eachcase, trash percentage and neps were measured. Tosee the effect of feed of heavier lap on card. theheaviest lap was considered for further experimentalwork. The lap was processed on the same card, andthree different drafts were used at the card to producedifferent sliver hanks. The carded slivers were drawntwice on draw frame. Quality tests on all produced

240 INDIAN 1. FIBRE TEXT. RES., DECEMBER 1994

slivers were conducted. Three levels of twistmultiplier were considered to prepare the ravings.Finally, the yarns were spun on ring frame by varyingthe break draft, spacer size, top front roller pressure,and back roller setting.

2.3 Measurement of Fibre DisorderThe fibre disorder in sliver was determined using

Lindsley's technique'. The proportion of curved fibreends (p) and the coefficient of relative fibreparalle1ization (k) were calculated from theequations suggested by Leont'eva- and the projectedmean length was calculated from the equationsuggested by Simpson and Paturean '.

Ep=--x100

E+N

k= (1- C ) x 100C+M+E

(Wr+ Wr)Projected mean length = T x t

Degree of relative fibre parallelization

Degree of straightening of curved fibre ends

:Ep)= Pi- Pi-I x 100Pi-I

whereT = (Cr+ Nr+ Er) + (Cr+ Mr+ Er) + M

E = Weight of fibre ends projecting over the line of cutafter combing

N = Weight of sliver proportion under the cuttingplate after combing

C = Weight of combed out fibreM = Weight of sliver proportion under middle plateW = Weight of combed clamped portion after re-

moving fibres not held by the clamps in forwarddirection (Wr) and reverse direction (W,)

t = Width of the platei = Ordinal number of operation.

3 Results and DiscussionThe results of two sets of experiment are given in

Table 1. In the first set, laps of three different hanks(0.00 I, 0.0015 and 0.0018) were processed on cardunder identical conditions. In the second set, the lapof 0.00 I hank was proeessed on card using differentdrafts.

Table 1 shows that there is no change in the blowroom cleaning efficiency as the trash percentage issame for all the lap hanks. Span length and uniformityratio do not show any change with lap hank. The nepsalso do not show any significant change. Therefore, itmay be concluded that the change in lap hank at blowroom has no significant effect on the quality of lap.

When these laps are processed on the same cardunder identical conditions (card draft, 96) asignificant reduction in the trash percentage (from0.3175 to 0.1363) and in neps/g (from 86 to 24) and tosome extent in span length is observed as the sliverhank changes from 0.106 to 0.185. This clearlyindicates the advantage of processing lighter lap atcard.

Table I-Trash percentage, fibre span length and neps in lap and sliver

Lap Card Sliver Trash Fibrograph Uniformity Nepsjghank draft hank % ratio (UR)

Ne 2.5% span 50% span 0/0

length lengthmm mm

0.0010 1.6 25.2 13.8 52 570.0015 1.6 24.8 13.1 53 570.0018 1.5 25.0 13.3 53 510.0010 96 0.106 0.317 24.1 Il.l 46 860.0015 96 0.160 0.170 24.7 .. 11.2 45 260.0018 96 0.185 0.136 24.7 11.6 48 240.0010 70 0.071 0.575 24.6 10.8 44 1680.0010 90 0.093 0.387 24.2 11.7 48 860.0010 110 0.113 0.216 25.7 11.8 46 53

ISHTIAQUE & VIJAY: OPTIMIZATION OF RING FRAME PARAMETERS

In the second set of experiment. a lap of 0.001 hankwas processed on the same card using card drafts of70.90 and 110 to produce sliver hanks of 0.071. 0.093and 0.113. The results (Table I) show a significantreduction in trash percentage and neps/g and increasein span length in sliver with change in card draft from70 to 110.

3.1 Fibre Disorder in SliverIt is observed that fibre disorder is influenced by the

change in lap hank and draft at card. The nature ofchange in the configuration of fibre in sliver(Tables 2-4) shows that the increase in sliver weight,either through lap hank or card draft, decreases theproportion of curved fibre ends, relative fibreparallelization and projected mean length. This canbe explained on the basis of deposition of operationallayers over cylinder. As we feed coarse lap or reducecard draft the operational layers on cylinder increasewhich result in increase in the carding force due tointer-fibre friction. This ultimately increases the fibrestraightening and decreases the proportion ofcurved fibre ends.

As the sliver hank becomes finer, either bychang: ng the lap hank or card draft, the coefficient ofrelative fibre parallelization and projected meanlength increase. This may be due to better opening of

241

fibres when lighter material is fed or higher draft isused.

Tables 2-4 further show that the proportion ofcurved fibre ends decreases and the value of relativefibre parallelization and the projected mean lengthincrease as the number of draw frame passageincreases. It is interesting to note that the decrease inthe value of p and the increase in the values of k andprojected mean length are more up to the first drawframe passage as compared to the second draw framepassage for both the cases and this is in agreementwith the findings of Simpson et at.5. But when we lookat the values of degree of straightening of curved fibreends (Ep and Ek), it is observed that the value of Ep ismore between the first and second draw framepassages (Table 4). This may be due to the feedingmajority of trailing hooks as trailing to the draftingsystem of second draw frame, which straightens outthe trailing hooks during drafting, and this is inagreement with the findings of Garde et at. 6. But thedegree of fibre parallelization is more between cardand first draw frame passage. This shows that themaximum fibre parallelization takes place up to thefirst draw frame passage.

A comparison of fibre orientation in sliver madefrom 0.0018 and 0.001 lap hanks at 110 card draftshows good resemblance. Therefore, it may be

Table 2-Proportion of curved fibre ends

Lap Card Sliver Carded sliver Breaker sliver Finisher sliverhank draft hank

Ne Forward Reverse Total Forward Reverse Total Forward Reverse Totaldirection direction direction direction direction direction

0.0010 96 0.\06 3.37 8.08 11.45 4.84 3.67 8.51 3.02 3.26 6.280.0015 96 0.160 3.40 8.55 11.95 6.76 3.83 10.59 3.04 4.12 7.160.00 18 96 0.185 3.78 8.57 12.35 7.22 4.21 11.43 3.18 4.65 7.830.00 IO 70 0.071 2.74 7.75 10.49 4.08 3.38 7.46 2.20 3.07 5.270.0010 90 0.093 3.16 8.57 11.73 4.33 3.90 8.23 2.64 3.11 5.75O.OOIO 110 0.113 3.58 8.79 12.37 5.35 4.64 9.99 3.21 3.42 6.63

Table 3--Coefficient of relative fibre parallelization

La~ Caru Sliver Carded sliver Breaker sliver Finisher sliverhank draft hank

Ne Forward Reverse Total Forward Reverse Total Forward Reverse Totaldirection direction direction direction direction direction

0.00 I0 96 0.\06 28.30 31.39 59.69 49.91 46.61 9652 49.30 49.50 98.800.0015 96 0.160 29.98 33.47 63.45 51.39 47.67 99.06 52.23 54.17 106.400.0018 9(, 0.185 31.42 35.35 66.77 51.44 49.37 101.31 51.94 56.30 106.240.0010 70 0.071 30.69 32.36 63.05 42.16 43.99 86.15 44.48 44.54 89.020.0010 90 0.093 31.33 31.78 65.11 49.93 48.53 97.96 49.56 49.20 98.790.0010 110 0.113 31.26 35.01 66.27 49.92 48.69 98.61 49.44 50.43 ')9.92

242 INDIAN J. FIBRE TEXT. RES., DECEMBER 1994

Table 4-Projected mean length and degree of fibre straightening and parallelization

Lap Card Sliver Projected mean length, in Degree of straightening Degree of fibrehank draft hank of curved fibre ends parallelization

NeCarded Breaker Finisher Card to 1st 1st drawing Card to 1st 1st drawingsliver sliver sliver drawing to 2nd drawing drawing to 2nd drawing

0.0010 96 0.106 0.30 0.51 0.56 25.67 26.23 38.15 2.310.0015 96 0.160 0.34 0.55 0.61 11.38 32.39 35.94 6.890.0018 96 0.185 0.36 0.58 0.61 7.45 31.49 34.09 6.40U.OOIO 7U 0.071 0.35 0.43 0.49 28.88 29.35 36.64 3.330.0010 90 0.093 0.40 0.52 0.56 29.84 30.13 30.54 0.820.0010 110 0.113 0.46 0.58 0.60 19.24 33.63 48.80 1.33

Table 5-Effect of break draft on yam properties[Top roller pressure, 15 kg; Spacer size, 3.5 mm; and Back roller setting, 51 mm]

Break Roving Count Lea Corrected CV % Tenacity Elonga- U% Imperfections/IOO mdraft TM Ne strength CSP g/tex tion

Ib Count Strength % Thin Thick Nepsplaces places

(-50%) (+3) (+3)

Roving hank, 1.011.15 1.45 37.0 54.7 2024 2.5 7.0 12.5 4.3 20.2 100 220 1431.30 1.45 36.8 55.7 2046 2.6 7.2 13.6 4.6 19.9 88 192 1471.46 1.45 37.2 54.8 2042 3.5 6.1 12.9 4.4 20.4 79 179 1281.15 1.60 36.5 59.6 2166 2.3 4.4 13.3 4.4 18.7 40 171 1001.30 1.60 36.3 57.3 2067 2.6 5.5 13.9 4.8 19.5 105 196 1371.46 1.60 36.3 57.2 2064 2.3 5.0 13.9 4.5 20.1 94 215 1411.1.5 1.75 37.1 54.3 2016 2.3 7.8 13.1 4.6 18.5 33 168 921.30 1.75 36.9 55.6 2050 2.9 8.2 13.1 4.3 20.7 Hl5 215 1671.46 1.75 37.2 54.9 2046 2.9 6.7 12.5 4.2 20.8 85 195 123

Roving hank, 0.861.15 1.45 36.5 53.9 1961 2.3 6.3 14.3 5.1 19.6 149 235 2701.30 1.45 37.2 54.4 2027 2.6 6.8 13.8 4.8 19.3 88 168 2071.46 1.45 37.0 50.7 1'876 2.3 6.5 14.0 5.0 19.7 132 202 2621.15 1.60 38.2 50.2 1938 2.9 6.5 13.6 5.0 19.8 108 220 2101.30 1.60 38.0 54.6 2095 2.7 6.8 13.9 5.1 19.7 102 198 2121.46 1.60 39.0 50.0 1986 3.6 7.3 13.4 5.0 20.2 105 210 249115 1.75 36.5 51.9 1885 3.4 8.9 13.3 4.5 20.4 132 227 2341.30 I. 75 36.7 53.8 1970 2.6 6.5 13.0 4.3 19.9 119 21.9 2601.46 1.75 36.0 52.3 1865 2.4 8.6 12.8 4.3 21.0 150 277 304

coocluded that a good quality of sliver can beproduced from a heavy lap by using high draft at card.T?is indi.cates the possibilities of better yarn qualityWith optimum spinning parameters which are.dealtbelow.

frame and rovings of O.70,0.86 and 1.0Ihanks wereproduced by using 1.45, 1.60 and I.75 twistmultiplier. Break draft, top roller pressure, spacersize and back roller setting were considered as ringframe variables to produce 37s Ne. It was founddifficult to produce 37 Ne count from 0.70 rovinghank. Therefore, roving hanks of 0.86 and 1.0Iwereconsidered for the present study.

3.2 Effect of Speed Frame and Ring Frame Variables on YarnProperties

The slivers of 0.071, 0.093 and 0.113 hanks,obtained from 0.001 lap hank, were fed into speed

3.2.1 Effect of Roving Twist MultiplierThree levels ofTM (1.45, 1.60 ana 1.75) were used

ISHTIAQUE & VIJAY: OPTIMIZATION OF RING FRAME PARAMETERS 243

to produce rovings of different hanks. These rovingswere processed on ring frame at different levels ofbreak draft, back roller setting and top rollerpressure. The results of roving of 1.01 hank show thatyarn CSP and yarn tenacity increase to a maximumvalue and then decrease as the roving TM increases.Similar results were obtained by Audivert andVidiella 7. The trend is same for all the four variablesof ring frame considered for the study.

The yarn uniformity first increases and thendecreases with increase in roving TM in majority ofthe cases. The imperfections in the yarn do not showany regular trend. In general, for 1.01 roving hank,1.60 TM gives the best results.

But when we compare the results of 0.86 rovinghank, it is observed that the results of 1.45 TM and1.60 TM are comparable but further increase in TMdeteriorates the yarn quality drastically. This can beexplained on the basis that the increase in roving TMincreases the inter-fibre friction due to more contactarea which' creates problem during drafting andultimately deteriorates the yarn quality.

3.2.2 Effect Vf Break DraftThree levels of break draft (1.15, 1.30 and 1.46)

were considered, keeping the other variablesconstant. Table 5 shows that yarn CSP 'and yarntenacity increase to a maximum value and thendecrease as the break draft increases. This is inagreement with the results of Audivert and Vidiella 7•

A consistent relationship exists between yarnevenness and break draft; the relationship shows adeterioration in yarn evenness with an increase inbreak draft. But imperfections do not show any trendwith the break draft. Hasan" suggested low breakdraft with a wide craddle opening for better spinningperformance. The results of 0.86 and 1.01 rovinghanks show that yarns made from 0.86 roving hankhave more imperfections but less strength anduniformity.

3.2.3 Effect of Top Roller PressureThree levels of top roller pressure (12, 15and 17kg)

were used. Table 6 shows that the yarn CSP and singleyarn strength increase to a maximum value and thendecrease as the top roller pressure increases. It is

Table 6---Effect of top roller pressure on yarn properties[Break draft, 1.30; Spacer size, 3.5 nun; and Back roller setting, 5 I mm]

Top Roving Count Lea Corrected CV% Tenacity Elonga- U% Imperfections/ 100mroller TM Ne strength CSP g/tex tionpressure Ib Count Strength % Thin Thick Nepskg places places

(-50%) (+ 3) ( +3)

Roving hank, 1.01

12 1.45 36.5 53.2 1933 2.5 6.4 13.0 4.2 21.2 118 244 15915 1.45 36.8 55.7 2046 2.6 7.2 13.6 4.6 19.9 88 192 14717 1.45 36.8 50.6 1862 1.9 6.1 12.1 3.7 19.2 72 187 10812 1.60 37.1 53.8 1998 2.8 6.7 13.5 4.8 20.8 116 233 14615 1.60 36.3 57.3 2067 2.6 5.5 13.9 4.8 19.5 67 190 13717 1.60 36.2 57.6 2051 2.6 4.0 13.5 4.7 19.7 68 187 12212 1.75 36.8 53.7 1973 2.8 5.5 12.5 4.2 21.6 156 249 18715 1.75 36.9 55.6 2050 2.9 8.2 13.1 4.3 20.7 105 215 16717 1.75 36.6 56.7 2008 2.0 5.7 13.0 4.2 19.7 78 222 128

Roving hank, 0.8612 1.45 37.1 51.8 1925 3.9 8.9 13.0 4.8 19.4 90 175 22815 1.45 37.2 54.4 2027 2.6 6.8 13.8 4.8 19.3 88 168 20717 1.45 36.9 52.0 1917 2.5 6.4 13.5 4.2 18.4 84 158 20312 1.60 37.2 49.3 1836 4.0 10.2 13.6 4.7 20.3 115 187 23315 1.60 38.0 54.6 2095 2.7 6.8 13.9 5.1 19.7 102 178 21217 1.60 36.3 52.3 1886 2.4 5.3 13.9 5.1 19.7 94 166 20312 1.75 '35.7 53.5 1887 2.9 8.1 13.7 4.8 20.2 110 208 24715 1.75 36.7 53.8 1970 2.6 6.5 13.0 4.3 19.9 119 219 26017 1.75 37.4 50.0 1877 1.6 5.3 12.8 4.6 19.9 108 200 240

244 INDIAN J. FmRE TEXT. RES., DECEMBER 1994

interesting to note that there is a regular improvementin yarn uniformity and reduction in imperfections asthe top roller pressure increases. The trend is same forboth the roving hanks. This can be explained on thebasis of better gripping of fibres at roller nip whichavoids fibre slippage during roller drafting andimproves the yarn quality. Yarns made from 0.86 and1.01 roving hanks are almost comparable.

3.2.4 Effect of Spacer SizeThree levels of spacer (3.0, 3.5 and 4.0 mm) were

considered to observe its influence on yarn pro-perties. Table 7 shows that for yarns made from 1.01roving hank, the yarn CSP and single yarn strengthincrease to a maximum value and then decrease as thespacer size increases. The yarn uniformity firstimproves and then deteriorates with the increase inspacer size. This is in agreement with the findings ofBalasubramanian".

The results of yarns made from 0.86 roving hankshow that the yarn CSP and single yarn strengthdecrease invariably as the spacer size increases. Yarnuniformity deteriorates and the total number ofimperfections does not show any trend with theincrease in spacer size.

3.2.5 Effect of Back Roller SettingThe influence of back roller setting (49, 51 and

53 mm) on yarn properties (Table 8) shows that theyarn CSP and' single yarn strength increase to amaximum value and then decrease with increase inback roller setting. Yarn uniformity first improvesand then deteriorates with the increase in back rollersetting, and the total imperfections first decrease andthen increase with the increase in back roller setting.Back roller setting of 51 mm gives the best reuslts forboth the roving hanks.

On the basis of above discussion, it may beconcluded that each variable at ring frame has anoptimum value which gives overall good quality ofyarn. For 1.01 roving hank, the best results areobtained at 1.6 roving TM, 1.15 break draft, 51 mmback ro\1er setting, 3.5 mm spacer size and IS kg fronttop roller pressure. But from 0.86 roving hank,overall good quality yarn is obtained at 1.45 rovingTM, 51 mm back roller setting, 3 mm spacer size, IS kgfront top roller pressure and 1.3 break draft.

A comparison of experimental yarn with the millyarn and ATIRA norms (Table 9) shows that theexperimental yarns are identical in terms ofCSP and

Table 7-Effect of spacer size on yarn properties[Top roller pressure, 15 kg; and Back roller setting, 51 mm)

Roving Count Lea Corrected CY % Tenacity Elonga- U %TM Ne strength CSP g/tex tion

Ib Count Strength %

SpacerSILt:

mm

Imperfections/100 m

Thinplaces

(-50%)

Thickplaces(+3)

Neps

(+ 3)

Roving hank, 1.013.0 1.45 37.9 47.8 1828 2.2 9.1 11.1 3.7 21.0 215 278 3143.5 1.45 36.8 55.7 2046 2.6 7.2 13.6 4.6 19.9 88 192 1474.0 1.45 37.6 48.7 1842 2.5 7.7 12.5 3.8 20.6 132 224 2223.0 1.60 36.2 55.5 1995 2.2 6.2 13.9 4.5 21.1 142 245 2663.5 1.60 36.3 57.3 2067 2.6 5.5 13.8 4.8 19.5 67 196 1374.0 1.60 35.7 54.9 1937 2.3 8.1 13.0 4.5 20.9 139 242 2383.0 1.75 38.2 50.4 1947 2.4 5.5 12.5 4.4 20.1 140 243 2643.5 1.75 36.9 55.6 2050 2.9 8.2 13.6 4.4 19.7 105 215 1674.0 1.75 37.0 53.3 1972 1.5 4.6 13.5 4.7 20.7 131 250 240

Roving hank, 0.863.0 1.45 37.0 55.8 2065 2~ 5.4 14.0 5.1 18.8 62 146 1693.5 1.45 37.2 54.4 2027 2.6 6.8 13.8 4.8 19.3 88 168 2074.0 1.45 37.0 53.0 1961 2.1 5.9 13.6 4.9 19.8 105 188 2583.0 1.60 39.1 52.2 2077 3.6 8.5 14.7 5.0 19.5 105 205 2293.5 1.60 38.0 54.6 2095 2.7 6.8 13.9 5.1 19.7 102 198 2124.0 1.60 39.8 47.8 1954 3.6 7.5 13.7 5.2 19.8 131 202 2513.0 1.75 36.7 53.9 1973 2.0 7.0 12.9 4.2 19.7 115 214 262

. 3.5 1.75 36.7 51.1 1870 2.6 6.5 12.6 4.0 19.9 119 219 2604.0 1.75 37.2 50.2 1871 2.4 8.6 12.6 4.4 21.0 115 222 239

ISHTIAQUE & VIJAY: OPTIMIZATION OF RING FRAME PARAMETERS 245

Table 8-Effect of back roller setting on yarn properties[Break draft. 1.3; Top roller pressure. 15 kg; and Spacer size. 3.5 mm]

Back Roving Count Lea Corrected CY % Tenacity Elonga- U% ImperfectionsjlOO mroller TM Ne strength CSP g.tex tionsetting Ib Count Strength % Thin Thick Nepsmm places places

(-50%) (+3) (+3)

Roving hank, 1.0149 1.45 36.0 53.4 1964 2.4 7.8 12.4 4.2 20.6 118 230 14351 1.45 36.8 55.7 2046 2.6 7.2 13.6 4.6 19.9 88 192 14753 1.45 36.5 52.5 1907 2.1 5.7 12.5 4.5 21.5 161 252 15749 1.60 36.1 54.8 1962 1.9 5.8 12.5 4.3 20.0 88 241 171

51 1.60 36.3 57.3 2067 2.6 5.5 13.9 4.8 19.5 67 196 137

53 1.60 35.8 54.0 1906 2.6 6.5 12.9 4.6 20.6 201 273 179

49 1.75 36.7 50.6 1855 2.4 6.5 12.3 4.1 20.8 93 214 179

51 1.75 36.9 55.6 2050 2.9 8.2 13.1 4.3 20.7 105 215 167

53 1.75 36.3 53.4 1926 1.9 6.2 12.8 4.1 21.0 100 212 132

Roving hank, 0.8649 1.45 37.8 51.1 1946 2.5 7.6 13.5 4.7 20.0 170 207 26251 1045 37.2 54.4 2027 2.6 6.8 13.8 4.8 19.3 88 168 20753 1.45 37.4 50.6 1900 2.1 5.6 12.0 4.7 20.0 118 173 21449 1.60 37.5 53.0 1997 1.9 7.9 12.4 4.5 19.5 111 189 23651 1.60 38.0 54.6 2095 2.7 6.8 13.9 5.1 19.4 102 198 21253 1.60 36.7 52.1 1907 2.6 5.5 13.2 4.8 20.2 123 189 23349 1.75 36.9 52.8 1947 2.7 '9.0 13.4 5.1 19.8 70 201 24551 1.75 36.7 53.8 1970 2.6 4.3 19.9 6.5 13.0 119 219 26053 1.75 35.5 55.2 1940 3.2 6.5 14.0 5.2 20.0 114 176 215

Table 9--Comparison of experimental yarn. mill yarn and ATIRA norms

Count Corrected U% Imperfectionsjl 00 mNe CSP

Thin Thick Nepsplaces places

(-50%) (+3) (+3)

ATIRA norms 37 1800 18.5 40 95 85Mill yarn 37 2100 18.0 30 98 97Experimental yarn (1.01 roving hank) 37 2166 18.7 40 171 100Experimental yarn (U.~6 roving hank) 37 2065 18.8 62 146 169

yarn evenness but have higher imperfection level incomparison to mill yarn. Also, the imperfection levelin experimental yarn further increases as the rovinghank becomes coarser.

A comparative study of preparatory particulars ofexperimental yarn and mill yarn (Table 10)shows thatthere is a direct gain in production at all the stages byusing coarser hank in the preparatory process. Thisultimately results in savings in capital, labour, power,and space costs. It is, therefore, recommended thatfor a particular end use where imperfections can be

Table lO--Gain in production at various stages of spinning

Mill yarnparti-culars

Experi-mental

yarn parti-culars

Gain inproduc-

tion0/0

Lap hank, NeCard sliver hank. NeDrawing sliver hank. NeRoving hank. NeDraft at ring frame

0.001540.160.1661.6

23.12

0.00\0.1130.1171.00

37

35.0629.3729.5237.50

246 INDIAN J. FmRE TEXT. RES., DECEMBER 1994

tolerated up to certain extent, such an exercise will behighly economical.

4 Conclusions4.1 Production of heavy lap at blow room does notshow any significant effect of blow room cleaningefficiency and neps/g.4.2 Trash percentage in sliver and neps/g increasewith the decrease in card draft.4.3 The proportion of curved fibre ends and thecoefficient of relative fibre parallelization in sliverdecrease with the increase in lap weight and decreasein card draft.4.4 Projected mean length decreases with increase insliver weight, either through change in lap hank orcard draft.

4.5 The degree of fibre parallelization is morebetween carded and first drawn sliver but the degreeof straightening of curved fibre ends is more betweenfirst and second drawn slivers.

4.6 For 1.01 roving hank, the best results are obtainedat 1.6 roving TM, 1.15 break draft, 51 mm back rollersetting, 3.5 mm spacer size and 15 kg front top rollerpressure. But from 0.86 roving hank, overall goodquality yarn is obtained at 1.45 roving TM, 51 mmback roller setting, 3 mm spacer size, 15 kg front toproller pressure and 1.3 break draft.4.7 Yarns made from coarse hanks at preparatorystages using optimum spinning parameters arecomparable to mill yarn and ATIRA norms.

ReferencesI Lindsley C H, Texl Res J. 21 (1951) 39.2 Leont'eva I S, Technol t-«. USSR, 2 (1964) 58.3 Simpson J & Paturean M A, Texl Res J, 40 (1970) 956.4 Sengupta A K, Vijayaraghavan M& Singh A, Indian J Text Res,

8 (1983) 611.5 Simpson J. Sand J E & Fiorie LA. Text Res J, 40 (1970) 42.6 GardeA R, WakankarV A& Bhaduri S M, Text ResJ, 31 (1961)

1026.7 Audivert R & Vidiella J E, Text Res J, 32 (1962) 652.8 Hasan M El-behery, Text Res J, 41 (1971) 379.9 Balasubramanian N, Text Res J, 41 (1969) 155.