feedingconditions.pdf

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Textile Research Journal

http://trj.sagepub.com/content/43/1/1The online version of this article can be found at:

DOI: 10.1177/004051757304300101

1973 43: 1Textile Research JournalN. Balasubramanian and G.K. Trivedi

Effect of Feeding ConditiQns at the Ringframe Upon Yarn Quality and Spinning Performance

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Effect of Feeding ConditiQns at the Ringframe Upon Yarn Qualityand Spinning Performance

N. BALASUBRAMANIAN AND G. K. TRIVEDI

The Bombay Textile Research Association, Lal Babadus Shastri Marg, Ghatkopar (West), Bombay-86, India

ABSTRACT

The paper deals with studies elucidating the effects of hank of the ingoing material and of doubling at the ringframe upon yarn quality and spinning performance under different spinning conditions obtained by varying the spindle speed andcount spun. The results show that with coarse and medium mixings, the hank of the roving fed could be varied overa wide range without affecting yarn properties. The use of finer hank, however, led to a reduction in end-breakage ratein such mixings. With fine mixings, finer input hank and low ringframe drafts led to poorer yam quality and comparableor poorer spinning performance.

Doubling at the ringframe improved the strength and regularity of yarns significantly in the case of coarse and mediummixings but only marginally in the case of fine mixings. The improved yarn quality thus obtained did nbt lead to betterringframe performance and the relative merits of single and double feeds in this regard were dependent upon mixingcharacteristics and spinning conditions. With coarse mixing, double feed invariably led to inferior spinning performanceand the effect became highly pronounced when overspinning or at higher spindle speeds. With fine mixings, the twofeeds were comparable at lower counts and spindle speeds but the deterioration in performance with increase of countor spindle speed was more rapid with double feed. In double feed spinning, end breakage rate was found to be loweron those spindles where the rovings were kept together by means of a cross-over of the strands in the break draft zone.The application of a condenser to keep the strands together was helpful in overcoming the deterioration in spinning per-formance in double feed. The Minimum twist spinning test showed a better correspondence with end breakage rateunder adverse conditions of spinning than under normal conditions.

KEYWORDSIndian cotton; American (Elpaso) cotton; Egyptian (Giza 45) cotton. Yarns. Cotton fiber properties; mixing fibers.

Hank input; ringframe single feed; ringframe double feed; ringframe draft ; lea CSP; roving U%; spindle speed; condenser.Strength; elongation; Uster %; Fielden Walker PMD; micronaire; end breaks; minimum twist; ends down; count spun;end-breakage rate. Spinning performance; yarn quality; Feeding conditions; ringframe.

Introduction

..~ low level of end breakages in spinning is one of therherished goals consistently sought by every spinnerfor minimizing the cost of yarn manufacture. Attemptsto improve the ringframe production through higherdelivery rates are unlikely to succeed unless preceded bymeasures designed to bring down the end breakages.An analysis of the contribution from the differentsources towards spinning performance is, therefore, asubject matter investigated in detail by many researchworkers.The performance of a ringframe is ctosety linked with

t he quality of yarn, as majority of end breaks are causedby the inability of the yarn to withstand the spinningtension. All other factors remaining the same, spinningorganization may be expected to have a considerablcin8uence over the quality of yarn spun. Working onWhitin long-draft ringframes equipped with casablancaapron cradles, Simpson ~6, 7, 8~ el al. found that spin-ning draft has more effect upon yarn strength anduniformity than other process. The optimum draftwas found to vary with count spun and characteristics

of the cotton. H;arlier work p one of the presentauthors [1~ has, however, indicated that the hank of theinput roving and ringframe draft can be varied over a

wide range in top arm drafting without affecting yrnquality in coarse and medium varieties of cotton.

I)oubling at the ringframe is one of the means sug-gl-sted for getting improved yarn quality. Althoughthis matter has been investigated earlier by manyauthors, no uniform conclusions have been obtained sofar in this regard probably because of the varyingdrafting conditions under which the difterent expertments have been performed. Sampson E9] et al. foun4that on Whitin casablanca drafting system the benefitsof doubling depend upon the count spun as wel as theringframe draft. Based on a study covering fourdrafting systems, Ratnam ES] concluded that there islittle difference between the quality of yarn betweensingle and double feeds in counts 40&dquo; and above. Inthe only count 30&dquo; reported in his work, improvementsin lea strength and Uster evenness were observed with.double roving.

In an earlier study in 13TRA [2], yarns in the countrange 16&dquo; to 40 were spun on top arm drafting from


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same rovings as single and double feeds from a mediumstaple Indian cotton. The irregularity of the productfrom double feed was significantly lower than that fromsingle teed over the entire count range, the Irregularity-count lines for the two feeds being roughly parallel toeach other. The&dquo; improved regularity from doublingarose because of the slow rate of increase of irregularitywith draft in top arm drafting and the independentdrafting of thc two strands. Experimental evidence to

the latter effect was provided in another work ~i~. Itis, however, more useful to compare double feed withsingle feed at the same draft and for this a detailedknowledge about the influence-of ingoing hank and ring-frame draft is required.From the foregoing, it is evident that, by optimizing

the input hank and by recourse to doubling at theringframe, upgrading of yarn quality would be feasibleunder certain specified conditions. The end breakagein spinning is, however, not entirety determined by thequality of yam spun but is also affected by the condi-tions of spinning. More than the strength of the fullvspun yarn, the strength of ,the material close to thefront roller_ nip has a critical influence over the endbreakage rate, as the yarn is only partiallv twisted inthis zone. The strand width at the nip has a critical

. bearing wd the run of twist, spinning from a widerstrand leading to poorer flow of twist to the nip.Coarse input hank and double feed enhance the strandwidth. Thus in addition .to their influence over yarnquality, feeding conditions at the ringframe may alsobe expected to have an effect over spinning performance.The present work inve$tigates this matter in detail fora range of mixings spun under varying spinning -condi-tions. With the present trend -towards nigh-speedspinhing, studies in this direction are considered useful

< in evolving guidelines for optimizing yarn quality andspinning performance.

.

- co

Effect df Roving Size and Doubling..

~ on Yarn Properties,

. <

-

,

To assess more precisely the effects of hank of theingoing material and doubling,, five cottons representinga wide range in fiber properties (cottons numbered 1 to 5in Table I) were spun into counts to which they arenormally spun, using-the different feeding arrangementson a ringframe,equipped with top arm drafting. ThreeIndian cottons (one coarse and two medium), oneAmerican (Elpaso) cotton, and one Egyptian (Giza 45)

., cotton were used in this work. Two roving hanks, onetwice as fine as the other, were prepared from each

cotton from the same finisher drawing sliver by adjust-ing the, drafts at the two zone can fed speed frame.Three spinnings were done from each cotton, two assingle feed from the coarse an4 fine hanks and the thirdas double feed from the fine hank. The hanks were sochosen that the ringframe draft is about 25-30 whilespinning from the coarse hank, .as this is the commonly

-.-- TABLE I. Fiber properties of the cottons.- -- .---. -

used draft in the industry in top arm drafting. WSI,UT3 drafting was used in spinning the Indian cottons,

while SKF drafting was used in spinning the Americanand Egyptian cottons. rhe break drafts, roller settingsand the apron spacings were kept the same for the differ-ent feeding conditions to obtain identical drafting condi-tions. The yarns were tested for lea strength and Lsterevenness and the results are given in rable II. In theUster test a material speed of 25 m ~min for yarns and8 m/min for rovings were used.Two features stand out prominently in the results

presented in Table H. Firstly the hank of the naterialfed (or the ringframe draft) has little effect either onstrength pr the regularity of the yarn in the coarse andmedium varieties of cottons, i.e., Katyan, I)igvijty,-, andCOz. But with long staple cottons, i.e., Elpaso andGiza 45, the quality of yarn deteriorates with tine inputhanks and low ringframe drafts. The deteriorationcannot be ascribed to any difference in thc~ quality ofthe rovings themselves, since the difference i regularityof the rovings does not appear to be higher than couldbe accounted by the difference in hank. It appears,therefore, that with long staple cottons, the quality ofdrafting at the ringframe suffers with the use of tineinput hanks and low ringframe drafts.The second important feat ur~ i~) that doub~e-feeci

spinning from fine-hank leads to improvements instrength and* evenness of yarns when compared withsingle-feed spinning of the same hank for all the cottonsexcept Giza 45 where imprqvements in evenness are not

seen. If double feed is compared with single feed ofcoarse hank, which is of more practical interest, theimprovements in strength and evenness are still promi-nent with coarse and medium vpttons but are onlymarginal with long staple cottons. Thus, doubling atthe ringframe,,offers a convenient means of &dquo;upgradingthe lea strength and evenness of yarns spun from coarseand medium varieties of cottons.


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In the foregoing studies, roving hanks in the extremeends of the scale alone have been investigated and nonein the intermediate rang; has been includecl. Further,higher speedframe draft had been used in the prepara-tion of finer rovings which mi~ht have affected thequality of the roving, Further studies were, therefore,to make gooti these limft7ttions. Two Indian cottons(I)igvijay and (()2) and one Egyptian cotton (Menouti)were used for these studies. ((ottons arenumbered 6to 8 in Table 1.) Although the Indian cottons bear thesame name as those used in carlicr work, they belonged

to different lots and differed in fiber propertics as will beseen in rable I. Three roving hanks were preparedby alteration of the speedframe draft. Single-feedspinnings were done from each of the hanks whiledouble-feed spinning was done from the medium andtine hanks. A limited quantity of finer-hank materialwas also prepared without alteration of the speedframedraft. For this purpose, the doubling at the finisheidraframe was cut, down from six to three so that thehank of the sliver fed to the speedframe was made twiceas fine. The material thus prepared was compared w ith

TAMLE II. Effect of hank of the ingoing material and doubting upon physical properties of yam..

TARLH Ill. Ktleft of hank4 the ingoing material and douhtinK upon physical properties of yam ~

Prepared without alteration of the speedframe draft by making the finisher drawing sliver finer.I.M.U. = Per cent Mean Deviation

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