pa01 friction spinning - a new spinning technology

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F riction Spinning ANew Spinning Technology *E.G. Smalley

The technical and economic limitations of conventional ring spinlng have been a subject of muchdiscussion and are proving to be an ever increasing burden for all spinners of staple fibres incotton, wool and man-made fibres. As a result, staple fibre spinners and textile machinerymanufacturers have been continuously engaged in research and development work to find newmethods of spinning which will overcome the limitations imposed by the conventional ringspinning system. This paper introduces a new concept of open-end spinning, developed anddesigned by platt Saco Lowell (UK) limited, for the short staple spinning industry.

1. IntroductionA s a background to this new technology it w ill b euseful to consider briefly the various spinningmethods which were developed in recent years as asub stitu te to rin g sp in nin g.

Rotor SpinningThe m ost successful and com mercially acceptedsystem is rotor spinning (Fig.1). T his system has now

Fig. 1 Rotor Spinning Systembeen commercially used for some 15 years andalthough the m arket penetration initially expectedwas not achieved, in terms of volume of yarnproduced, rotor spinning represents a slgnlflcantm ark et sh are.

Rotor Spinning showed the most early prom ise ofth e open-end system s and initially m ost m achines

were operating at speeds in the range of 30,000 to45,000 rpm rotor speed. In the 1970's considerableeffort w as devoted to developing. Rotor Spinningmachines able to operate at rotor speeds of 100,000rpm . This work highlighted that rotor spinning hadtwo fundamen ta l and-, u na vo id ab le d rawb ac ks whic him po sed sp eed lim itatio ns. T he first w as th e n ecessityto rotate a relatively large m etal rotor at high speed.This problem led many companies to investigatevarious types of bearings including "air" -and"m agnetic" bearings and individual motor drives.A lthough technically viable, m ost of these system swould be discounted due to high costs.The second drawback is more fundamental andrelates to the effect of increased rotor speed onspinning tension. The yarn is tw isted by a yarn crankw hich leads from the doffing tube to the rotor w all;any increase in rotational speed increases thecentrifugal forces in the crank and consequentlyincreases the spinning yarn tension. This can besom ewhat com pensated by a reduction in the size ofthe rotor but on the other hand there is a m inimum

diameter which is determ ined primarily by fibrelength. However with improvements in spinningtechnology and bearing design rotor spinningmachines are now being operated comm ercially atrotor speeds in the range of 60,000 to 80,000 rpm .It is our opinion that rotor spinning productionrates are gradually reaching a plateau and that it is -doubtful w hetl;te', ~ey w ill rise m uch above presentlev els d ue to th e p en alties im posed b y a com bin atio n

..Paper presented at the International Textile- engineering Symposium held from Nov. 28-30, 1984.Printed with the tJermission of the Symposium committee of JodiafTME Sodety,

22 8 M A N M A D E T E X T I L E S I N I N D IA , J U L Y , : . ; : 1 9 ;, , : ; ; 8 5 ; ; . . . ._


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of higher capital cost, significantly increased pow erc osts. h ig he r n oise le ve ls a nd sp in nin g lim its im po se dby an increase in spinning tension,3. Vortex Spinning

The objectives of vortex spinning were toovercome the first fundamental problem of rotorspinning in that the m etal rotor w as replaced by an airvortex (Fig, 2,) This system still requires a radial

Fig. 2 Air Vortex Spinning (Polish PF 1)

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portion of yarn in a crank to be rotated at high speed.with the obvious resu ltant high centrifugal forces.There are further draw backs w ith the system : Problems can be caused due to trash The fibres are less controlled than on rotor spinni ng

w hich invariably result in w eaker yarn There is a high level of fibre loss. The machine has a high power consumptionprim arily due to air usage.This system has found suitable applications forproduction of core yarns with a filam ent core.

4. Air Jet SpinningThe prim ary patent on air jet spinning was filed asfar back as 1961 by D u pont. Subsequently an acrylicrotofil yarn was marketed by them under the tradenam e 'N andel'. Average fibre length was of theorder of 100 mm with a specially selected very widefibre length distribution to provide the fascinatedstructure. Further patents were filed by Toray andMu ra ta in th e e arly 1 97 0's in tro du cin g impro veme ntsw hich allow the system to operate m ore successfullyon short staple fibres. B oth patents refer to featurespositioned between the front drafting roller and thetw isting jet. T he T oray system (F ig. 3) has a speciallyconstructed apron arrangem ent. The aprons preventthe edge fibres from being rotated by the air jet andtherefore as the yarn passes through the jet these edgefibres are caused to wrap around the main body ofthe yarn. The M urata air jet system em ploys a contra

M AN M AD E TE XTIL ES IN IN DIA, JU LY 1985

rotating air jet, called an opening nozzle which, it isclaimed, creates a partial open end and thus allowsshort staple fibres to be processed.

ORIGINAL 011 PQNT BOTOFIL SYStEM

TO~'" A lA JE T SPINNING SUTEII

I lI 1I tAU. A1AJC T Sl 'IHNING "STEI l

Fig. 3 Air Jet Spinning Systems.

The jet spinning principle produces a unlque yarnw hich does not contain true tw ist, and therefore tw istcannot be selected according to the requirem ents ofthe end product. O n the other hand, it has thep ossi b le a dv an ta ge th at y arn s a re le ss tw is t- liv ely th antru e tw ist y arn s. T he m ac hin e is a sliv er to y arn sp in ne rusing a 3~ line double apron drafting system . D rafts ofthe order of 50 -2 50 a re available at an operating speedup to 180 m etres/m inutes. A t present the m achinesdo not process 100% cotton yarns.5. Friction Type Open-End Systems

For quite som etim e w e at Platt Saco low ell (U K ) ltdhave appreciated that the preferred open-endarrangement is one in which the yarn tail remainsstraight, and is tw isted about its ow n axis by contactw ith a m oving surface. This avoids high centrifugalforces and high rotational speeds because each turn2 2 9


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of twist is inserted by one rotation of a yarn with adiam eter of approxim ately 0.15 to 0.30 mm, w hereason rotor spinning it requires one revolution of therotor with a diameter of at least 38 mm to insert oneturn of twist. This represents a surface speedapproximately 125 to 250 times less than rotorsp inning for th e sam e tw ist insertion and is generallyachieved by utilising the principle of frictionspinning.

A number of systems of this type were patentedaround the late 60s by Platt Saco L owell and TheShirley Inst itute.

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At the outset it was appreciated that to achieve acom mercial yarn, the fibres m ust lie basically alongthe yarn axis and be twisted together whilst in thisstate.

C onsiderable progress has been m ade lnachlevlngthese objectives. The first area to be discussed is fibrealignment. In ring spinning fibre alignment isachieved in the preparatory processes, carding,d rawin g, ro vin g, c ombin g if employed , and dra ftingat the ring fram e itself. In open-end system s the fibresare at some stage in free flight in an air stream andhence are not under proper control. The depositionof the fibres from the air stream into the yarnstructure is therefore of paramount importance toobtain as parallel a structure as possible. In rotorspinning this is achieved by the acceleration of theleading end of each fibre as it encounters the rotorw all thus stretching the fibre out along the w all. In thefriction spinning system there is no high speedm oving part to achieve this function and therefore itmust be achieved as the fibres m ove in the air streamtow ard the yarn form ation area. V arious system s havebeen tried to align the fibres parallel to the yarn axisincluding electrostatic forces and rotating fans.

P latt Saco L owell (U K) L td have, however,developed a system employing an entirely newprinc iple . In this system (F ig.7) th e fib re tran sfer d uctleading from the opening roller to the yarn form ationarea includes an additional suction duct close to theyarn formation zone which is balanced w ith thesuction passing through the perforated roller.Therefore the fibres as they m ove along the transferduct, turn tow ards the additional duct to lie parallel tothe yarn, and then m ove in this orientation towardsthe yarn, The fibre transfer duct opens into a nozzle atthe additional duct to give room for this turningm ovem ent. T his effect is enhanced by the fact that thefibre transfer duct is directed at a carefully selectedangle to the yarn itself in a direction opposite to thew i thd r awa l d ir ec ti on .H aving first dev elop ed a system th at c ause th e fibresto lie sub stan tially alo ng the yarn a xis, it is essential toassemble the fibres in a way which optim ises thetextile properties of the final yarn. The system (F ig.Z )developed by Platt Saco L owell (U K) L td uses oneperforated roller which turns tow ards the throat andincludes a suction slot within the roller, and one non-perforated m etal roller turning aw ay from the throat.The, fibre feed duct extends close to the yarnform ation area and is biassed tow ards the perforatedroller so that fibres attach to the yarn by rollingbetween the yarn and the perforated roller rotatingtow ards the th roat.

MAN MAD E T EX TilE S IN IN DIA , J UL Y 1985

Flg.7 Friction Spinner,

The quality of the yarn is determ ined by : The correct choice of surface characteristic of boththe perforated and non-perforated rollers. The size and spacing of the holes in the perforatedroller. The setting and w idth of the suction slot within thep erf ora te d ro lle r.o The tw ist which is inserted into the yarn and isdeterm ined by the speed of the friction rollers{Fig .8 )

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The structure of most of the yarns mentioned in thispaper have been examined using stereoscanphotographs (Fig. 9) : The combed ring spun yarn has a ribbon likeappearance w ith w ell aligned fibres. O n the rotor yarn most of the fibres are alignedalong the yarn axis except for the wrapper fibres. The air je t y arn h as fa sc in ate d stru ctu re ,o O n the Platt Saco L ow ell (U K ) L td friction spun yarnthe fibre orienta tioin along th e yarn ax is is e vid ent,

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C OM BE D R IN GS PU N Y A R N

R OT OR Y AR N

A IR JE T Y A R N

D R E FWOOLLENY A R N

FRIC TIONSP U N Y A R NFig. 9 Siereoscans of Yarns Spun on Dif ferent Systems

there is no evidence of wrapper fibres; and sincethese pictu res were taken further progress has beenmade in elim inating the loose fibres evident on thesurface of the yarn.The technical characteristics of this new friction

spinning system , can therefore be summarised asfollows:., A[[ fi bres of 40 mm and less can be processed on the

machine. These include 100% cotton yarns, 100%synthetics and blends.., It is not necessary to have a special sliver prepara-tion system , a conventional plant suitable for O .E .spinning is perfectly adequate.

., The system normaly produces a cleaner yarn thaneither ring or rotor spun when there is cotton in thefeedstock, due to trash removal at the beater, andalso the removal of micro-dust through the per-fo rate d ro lle r.

o The spinning tension is low irrespective ofthroughput speed, and therefore does not createend breaks.

., The yarn is normally less neppy than either the onespun on the ring or the rotor spinning systems.Fig. 10 shows examples of both knitted and woven

fabrics from friction and ring spun yarns. It illustrates23 2

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R IN G S P U N Y A R N

K NIT TE D F AB RIC S: : W OV E N F A B R IC S

F RIC TIO N S PU N Y AR NFig. 10 Appearance of Knitted and Woven FabriCs from

Ring Spun and Friction Spun Yarns,

the clean, regular appearance of the fabrics madefrom friction spun yarn .., The productivity per position is 2 - 3 times greater

than the latest rotor spinning machines and this isachieved without having any component operatingat high rotational speeds; in fact the beater is thefastest m oving part.The machine was first publicly shown at the ITMA

Exhibition at M ilan in O ctober 1983. Then we exhi-bited tw o 10 spindle spintesters operating respectivelyon :

Ne30s (Nm50) cotton with a delivery speed of 210metres/mi nute

Ne24s (Nm40) 100% acrylic with a delivery speed of250 me tr es lminu te

The full length machine which is now in productionis a double sided machine of :

144 spinning positionsMachine gauge 224 mmDraft range 60 - 240Take-up package (cheese) 290 x 150 mmTake-up package weight 4.2 kgSliver can size (dia x height) 400 x 900 mmY arn delivery speed upto 300 mlmin

The machine can be delivered with cheese take-upor w ith cones up to 4020', W axing attachments can befitted for knitting applicatioins. The machine isprepared for measured length packages and forautom atic peicing and doffing.

M AN M ADE TEX TIL ES IN IND IA, J UL Y 1985

pa01 friction spinning - a new spinning technology

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