A study of preparatory cleaning on rotor-spun yarn propertiesnopr.niscair.res.in/bitstream/123456789/32591/1/IJFTR 15(1) 6-10.pdfA study of preparatory cleaning on rotor-spun yarn

Indian Journal of Fibre & Textile ResearchVol. 15, March 1990, pp. 6-10

A study of preparatory cleaning on rotor-spun yarn properties

S M IshtiaqueDepartment of Textile Technology, Indian Institute of Technology, New Delhi 110016, India

Received 17 July 1989; accepted 25 September 1989

Interrelationships between the degree of cleaning of cotton fibres and the properties of rotor yarns wereinvestigated. In the blow room machinery, different numbers of cleaning points were employed. The materialwas processed on single and tandem cards separately. Overall cleaning efficiency (blow room and card) wasnot affected significantly with the increase in the number of cleaning points. It is suggested that the blow roomcleaning should not be too intensive and a part of the cleaning load should be transferred to the card.

Keywords: Cleaning efficiency, Cleaning load, Cleaning points, Cotton fibre, Rotor-spun yam

1 IntroductionIn the early days of rotor spinning, yarn manufact-

urers were attracted by the potential of the process toreduce raw material costs by utilizing low-grade cot-ton and waste. Today, although it is accepted thatsuch raw material can be processed, it is also recogni-zed that greater attention has to be paid to the result-ant yarn quality and consequently, the cleanliness ofthe sliver.

The problem of dust and trash has beset the rotorspinning of cotton since its commercial application.In ring spinning, trash particles are thrown harmles-sly off the yarn as it balloons whereas in rotor spinn-ing, they tend to become embeded along with the dustparticles in the rotor groove 1- 3. The impurities anddust which accumulate in the rotor groove not onlyimpair the operating conditions of the machine andcause rapid wear of the rotor surface" but are alsoresponsible for the lower yarn quality and increasedyarn breakage rate>". Various methods have beenproposed all of which involve a vigorous cleaningaction using expensive ginning and blow room equip-ment. However, intensive opening actions may dam-age the fibres and thereby impair subsequent yarnproperties. Furthermore, faced with the prospect ofheavy capital outlay for rotor-spinning machines,mills may find the prospect even more daunting, iftheir expenditure has to extend to re-equipping theblow room to process their regular mixings.

In recent years, high prices have led to increasinguse of cotton with high trash content for spinning.Since, however, it is just the residual content of dirtand dustthat determines the quality of rotor yarns,cleaning efficiency must be raised to the necessary

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high level. It is still debatable whether blow roomcleaning should be as intensive as possible or part ofthe cleaning load should be transferred to the card.Therefore, proper cleaning at different preparatorystages is essential. For this reason, a study of fibrecleaning during the preparatory stages has been cons-idered to be of considerable importance. The presentstudy aims at ascertaining the effect of different clean-ing affinities of blow room and type of card on thequality of rotor-spun yarn.

2 Materials and MethodsThree cottons, viz. 1007, 197/3 and wagad, were

selected for the study. The specifications of these cott-ons are given in Table 1.

2.1 Sample PreparationAll the three cottons were processed on Platts blow

room machinery with the following sequence with 5Y2cleaning points.

(I) Bale breaker(2) Crighton opener-I

Table I-Specifications of cottons

Parameter Cotton

1007 197/3 Wagad

Trash. % 4.36 6.91 10.7Fineness, Me 4.2 4.8 5.6Effective length, mrn 28.5 26.5 22.5Mean length, mm 21.0 20.5 17.5Short fibre, % 24.0 21.0 18.0Maturity coefficient 0.70 0.76 0.66

ISHTIAQUE : ROTOR-SPUN YARN PROPERTIES

(3) Crighton opener-II(4) Porcupine opener(5) Three-bladed beater(6) Krishner beater

The trials on the three cottons were carried out inwhich the usual blow room equipment of three clean-ers was extended with I or 3 additional cleaning unitsgiving a maximwn of 5Y:z cleaning points. For 4% clea-ning points the Crighton opener-II and for 3% clean-ingpoints the Crighton opener-II and porcupine op-ener were bypassed. Each cotton and material delive-red by each of the cleaners (after every cleaning po-ints) as well as blow-room laps were analyzed fortrash content on the Shirley analyzer. The laps wereprocessed on single high production card and tandemcard. The trash percentage of each sliver was also

examined with the Shirley analyzer. All the samples ofsliver were processed on a high-speed draw frame andtwo passages were used. Finally, all the yarns werespun on a prototype Sussen rotor spinning machine.

3 Results and DiscussionTable 2 shows that cotton with 4.36% trash gave

1.78% trash in the lap (i.e. 59.2% blow room cleaningefficiency) after 3% cleaning points, 1.61% trash inthe lap (i.e. 63.1 % blow room cleaning efficiency) af-ter 4 Y2 cleaning points, and 1.36% trash in the lap (i.e.68.8% blow room cleaning efficiency) after 5% clean-ing points. When the other two cottons, 197/3 andwagad, were processed in the same order, the blowroom cleaning efficiency of the order of 63.5%,69.03%,74.67% and 67.19%, 72.52%, 77.94% wereobserved respectively (Tables 3 and 4). This clearly

Table 2-Blow room cleaning efficiency of cotton 1007

No. of cleaning points

3'1. 4'1. 5'1.

Trash Reduc- Cleaning Trash Reduc- Cleaning Trash Reduc- Cleaningcontent tion efficiency content tion efficiency content tion efficiency

% % % % % % % % %

3.18 1.18 26.06 3.18 1.18 27.06 3.18 1.18 27.062.42 0.76 23.90

2.47 0.71 22.30 2.00 0.42 19.802.23 0.95 29.80 1.97 0.50 20.20 1.64 0.36 18.001.78 0.45 20.18 1.61 0.36 18,26 1.36 0.28 17.10

59.20 63.\0 68.80

3.90 9.60

Table 3-Blow room cleaning efficiency of cotton 197/3

No. of cleaning points

3'1. 4'1. 5'1.

Trash Reduc- Cleaning Trash Reduc- Cleaning Trash Reduc- Cleaningcontent tion efficiency content tion efficiency content tion efficiency

% % % 0/0 % % % % %4.77 2.14 30.97 4.77 2.14 30.97 4.77 2.14 30.97

3.48 1.29 27.043.48 1.29 27.04 2.68 0.80' 22.98

3.42 1.35 28.30 2.68 0.80 22.98 2.14 0.54 20.142.52 0.90 26.31 2.14 0.54 20.14 1.75 0.39 18.22

Sequence of blowroom machine

Crighton opener ICrighton opener IIPorcupine openerThree-bladed beaterKirshner beater

Blow room cleaningefficiency, %Improvement in cleaningefficiency, %

Sequence of blowroom machine

Crighton opener ICrighton opener IIPorcupine openerThree-bladed beaterKi rsh ner beater--------------------------------------------------------------------------------------_ ...._------------------ ....._------------------------------------------ ..-------Blow room cleaningefficiency, %Improvement in cleaningefficiency, %

63.53 69.03 74.67

5.50 11.14

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INDIAN J. FIBRE TEXT. RES., MARCH 1990

Table 4-Blow room cleaning efficiency of cotton (Wagad)

No. of cleaning points

3% 4% 5%

Trash Reduc- Cleaning Trash Reduc- Cleaning Trash Reduc- Cleaningcontent tion efficiency content tion efficiency content tion efficiency

% % % % % % % % %

7.06 3.64 34.02 7.06 3.64 34.02 7.06 3.64 34.024.97 2.09 29.83

4.94 2.12 30.03 3.71 1.26 25.354.91 2.15 30.45 3.74 1.20 24.29 2.91 0.80 21.56

3.51 1.40 28.51 2.94 0.80 21.39 2.36 0.55 18.90

Sequence of blowroom machine

Crighton opener ICrighton opener IIPorcupine openerThree-bladed beaterKirshner beater

Blow room cleaningefficiency, %Improvement in cleaningefficiency, %

67.19 72.52 77.94

5.33 10.75

Table 5-Overall cleaning efficiency (blow room + card) of cottons

No. of Single card Tandem cardcleaningpoints Trash Reduction Cleaning Improve- Overall Trash Reduction Cleaning Improve- Overall

content % efficiency ment cleaning content % efficiency ment cleaning% % % efficiency % % % efficiency

% %

Cotton 1007

3% 0.55 1.25 70.2 87.38 0.34 1.44 80.9 92.204% 0.50 1.11 68.9 0.05 88.50 0.33 1.28 79.5 0.01 92.435% 0.43 0.93 68.4 0.12 88.76 0.28 1.08 79.4 0.06 93.57

Cotton IfJ7/3

3% 0.67 1.85 73.41 90.30 0.44 2.06 81.74 93.634% 0.59 1.55 72.43 0.08 91.46 0.40 1.74 81.31 0.04 94.215% 0.49 1.26 72.00 0.18 92.91 0.34 1.41 80.57 0.10 95.08

Cotton (Wagad)

3% 0.84 2.67 76.07 92.15 0.51 3.09 85.47 95.234% 0.71 2.23 75.85 0.13 93.36 0.45 2.49 84.69 0.06 95.795% 0.59 1.77 75.00 0.25 94.48 0.38 1.98 83.89 0.13 96.44

shows that with the addition of cleaning points for allthe three cottons the blow room cleaning efficiencyincreases. It was noticed from our results that blowroom cleaning efficiency increases with the increase intrash percentage in cotton. The residual trash in thecard feed reduced from 1.78% to 1.36% for cotton1007, from 2.52% to 1.75% for cotton 197/3, andfrom 3.51% to 2.36% forwagad cotton on increasingthe cleaning points from 3% to 5%.

This seemed a convincing argument for using morecleaning units. If, however, the card sliver is also cons-idered, it takes on a different appearance for all the

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three cottons (Table 5). In the single card, the differe-nce between the cleaning efficiencies achieved with31;2and 5% cleaning points reduces to 1.8% from9.6%,1.41 % from 11.14% and 1.07% from 10.75%(or 0.12% from 0.42%, 0.18% from 0.77% and0.25% from 1.15% by mass) for 1007,197/3 and wa-gad cottons respectively in the card feed with the hig-her trash contents recorded in the card feed comingafter the fewest cleaning passages in the blow room. Itis interesting to note that the difference in the totalcleaning efficiency (blow room + card) is 1.38%,2.61% and 2.33% for 1007, 197/3 and wagad cottons

ISHTIAQUE : ROTOR-SPUN YARN PROPERTIES

Table 6-Fibre length and short fibre percentage after carding of cotton

No. of Single card Tandem cardcleaningpoints Effective Mean Short Effective Mean Short

fibre length fibre length fibre fibre length fibre length fibremm mm % mm mm %

Cotton 1007

3% 27.9 19.3 29 28.1 19.7 274% 27.6 18.9 32 27.8 19.4 305% 27.4 18.1 36 27.4 19.0 33

Cotton 197/3

3% 26.1 19.9 24 26.3 19.9 234% 26.0 18.5 28 26.0 19.1 265% 25.8 17.7 33 25.9 18.6 31

Cotton (Wagad)

3% 21.7 16.7 21 22.1 17.1 204% 21.1 16.0 25 21.9 16.4 235% 20.7 15.1 29 21.7 16.0 27

Table 7-Properties of yarns spun from different cottons

Type of No. of Yarn Single Strength Elongation Elongation Uster Imperfections/ IoOOrn Ends down/card cleaning count yarn CV at break CV evenness 1000 rotor

points Ne strength % % % U% Thin Thick Neps hoursg/tex places places +3

-50% +3

Cotton 1007

Single 3% 14.2 11.3 5.7 9.8 3.6 13.3 49 181 226 27card 4% 13.9 10.2 6.9 8.4 3.8 13.8 53 237 310 39

5% 14.3 9.7 7.6 8.1 4.3 14.0 77 256 359 47

Tandem 3% 13.8 13.8 5.1 11.2 3.4 12.4 38 147 191 19card 4% 14.0 12.7 5.9 10.6 3.7 13.1 47 162 245 24

5% 13.7 11.4 6.4 9.7 3.7 13.6 69 191 280 31

Cotton 197/3

Single 3% 10.2 8.0 6.7 10.1 4.9 12.7 39 152 208 57card 4% 9.9 7.4 8.4 9.2 4.8 13.1 48 191 261 75

5% 10.0 6.5 8.9 8.6 6.4 13.3 57 222 367 95

Tandem 3% 9.8 9.3 5.7 11.4 3.8 11.3 25 119 141 37card 4% 9.9 8.6 7.8 10.7 4.2 11.9 34 160 189 58

5% 10.1 7.5 8·.0 9.3 4.9 12.6 42 187 258 76

Cotton (Wagad)

Single 3, 6.1 8.4 6.1 9.1 5.2 1l..4 32 124 140 93card 4% 5.8 7.8 6.7 8.6 5.7 11.6 48 160 203 114

5% 5.8 7.0 7.1 7.4 6.1 11.9 55 198 230 150

Tandem 3% 6.0 9.2 5.9 9.7 4.3 10.7 20 85 110 60card 4% 6.2 8.6 6.2 9.2 4.9 11.2 31 III 172 81

5% 5.9 7.2 6.9 8.1 5.0 11.6 38 147 204 94

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INDIAN J. FIBRE TEXT. RES., MARCH 1990

respectively. In the case of tandem card the differencebetween the cleaning efficiencies achieved with 3%and 5112 cleaning points reduces to 1.5% from 9.6%,1.17% from 11.4% and 1.58% from 10.75% (or0.06% from 0.42%,0.1% from 0.77% and 0.13%from.1.15% by mass) forl007, 197/3 and wagadcott-ons respectively in card feed and the difference in thetotal cleaning efficiency is 1.37%, 1.45% and 1.21%respectively.

The study of mean fibre length and short fibre perc-entage was carried out in all cases. It is observedfromTable 6 that with the increase in cleaning points themean fibre length reduces and short fibre percentageincreases significantly. But the mean fibre length isgreater and the percentage of short fibre is less for thetandem card in comparison to the single card.

These results show that after the blow room treat-ment the material is not adequately cleaned and open-ed. More cleaning points give better cleaning efficien-cy in the blow room but after better carding the overallcleaning efficiency is almost same with different num-bers of cleaning points for all the cottons. From this, itcan be concluded that blow room cleaning should notbe too intensive and part of the cleaning load shouldbe transferred to the card.

A comparison of the results of tandem and singlecards shows that the performance of tandem card isbetter in terms of cleaning efficiency. The differencebetween the overall cleaning efficiency (blow roomand card) achieved with 3% and 5112 cleaning pointsand the trash content in carded sliver are also less inthe case of tandem card. The better cleaning efficiencyof the tandem card can also be supported as follows.

The finisher card receives from the breaker card afine web of fibres in which the cotton tufts have alre-ady been substantially separated and which havebeen passed through a web purifier crush roll. Thefinisher card, therefore, has ideal conditions for com-pleting the process offibre separation and removal oftrash or microdust. At the same time, the breaker cardhas relatively coarse settings and card clothing wher-eas there are very fine settings and close point popula-tion on the finisher card. This facilitates a relatively

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gentle and progressive carding action so that fibrebreakage is lower on the tandem cards than on thesingle cards.

If the yarn properties in Table 7 are examined, theresults of these cleaning efforts appear very disappoi-nting indeed. All qualifying data for all the three cott-ons with 5% cleaning points in the blow room areinferior to those obtained with 3112 cleaning points inthe blow room. This is equally true for yarn tenacity,Uster value, imperfections and last but not least, theend breakage rate. But when we compare the singleand tandem cards the tandem card is found to be supe-rior to the single card in all respects. This can be expla-ined on the basis that due to the progressive cardingaction at the breaker and finisher, the tandem cardgives better orientation of the fibres in sliver and ulti-mately in yarn.

4 Conclusions4.1 Blow room cleaning efficiency increases with theincrease in the number of cleaning points.4.2 Overall cleaning efficiency (blow room + card) IS

not affected significantly with the increase in the num-ber of cleaning points.4.3 Mean fibre length reduces and short fibre percent-age increases with the increase in blow room cleaningpoints.4.4 Yarn properties deteriorate with the increase incleaning points.4.5 Tandem card is better in all respects than singlecard.4.6 Blow room cleaning should not be much intensiveand a part of the cleaning load should be transferredto card.

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1 (1978) 29.