A drawframe straightens and aligns fibers in sliver to improve quality. It drafts sliver by passing it through rollers with increasing surface speeds, reducing weight per unit length. An autoleveller maintains evenness by adjusting the draft based on fiber weight variations measured by scanning rollers. A drawframe improves sliver uniformity and strength for downstream processes like spinning.

1. Drawframe
Input:cardsliver
Output:Drawnsliver
##DifferencebetweencardsliverandDrawnsliver:
Cardsliver Drawnsliver
Fiberorientationinalldirection Fiberorientationintheparallel
directiontothesliveraxis
Manyfibersareprojectedoutfrom
sliver
Lessfibersareprojectedoutfrom
sliver
Hooks(leading&trailing)are
present
Lesshooks(leading&trailing)are
present
Irregularwt./unitlength Regularwt./unitlength
Cardsliverhaslessstrength Drawnsliverhasmorestrength
##Bothinputandoutputofadrawframeissliver.Thenwhywe
usedrawframe??
Answer: From apurelycommercialpointofview draw frameisoflittle
significance.Butitsinfluenceonqualityandevennessisgreater.The
cardedslivercontainsfiberswhichareorientedinvariousdirectionsand
theyarehooked.Theyentangledwithoneanotherandtheirweightperunit
lengthishigh.Theyareirregularandcontainsomeimpurities.Sotheyneed
aprocessforeliminatingtheseerrors.
Incottonspinninglinedrawframeisthedefinitivecompensationpointfor
eliminatingerrors.Thisdrawframe:-
 Straightenthefibersinsliver.
 Makethefibersmoreorlessparallel.
 Reducetheweightperunitlengthofsliver.
 Removedustfromsliver.
 Makeveryperfectblendingoffibers.

2. Workingprincipleofadrawframe:
1.Feedingofmaterial:Fourtoeightcardslivercan(feedcan)are
fedatbelowofcreelframe.Thesesliversarethecreeledandfedto
thedraftingarrangementthroughafeedrollerpairlocatedabove
eachfeedcantoenablethefeedinginacontrolledmanner.
2.Draftingofmaterial:Thesliversthenrunthroughthedrafting
arrangementwhererangeofdraftof4to12asrequiredisapplied.
Herestraightening,parallelization and attenuation operation take
place.
3.Sliverformation:afterleavingthedraftingarrangementapackage
offiberiscalleddraftedweb,lackingsignificantcohesionbetween
fibers is produced.In this condition the fibers do notform a
transportableintermediateproductinordertoavoiddisintegrationof
theweb.Theintermediatetransportableproductsliverisproduced
aftercondensingthedraftingwebpassingthroughthecondensing
tube(trumpet)justafterleavingthedraftingarrangement.
4.Deliveryofmaterial:Thissliveristhenguidedthroughatubeviaa
passageofthecoilertubegearintoadeliverycaninwhichitmustbe
laidincleancoilswithoptimalutilizationofthespaceinthecan.To
enablethecantotakeupasmuchmaterialaspossible,thesliveris

3. compressedbypassingitthroughcalendaringrollers.
5.Doffingofmaterial:Thefilledcanispreparedforthedoffing
operation.Thereiscantrackforfeed-inoftheemptycananddelivery
-outofthefilledcan.
Mainobjectivesofadrawframe:
1.Toremovemajorityofhookspresentincardsliver
2.Toincreaseuniformityofsliver
Objectsofdrawframe:
1.Tostraightenthehookedfibersinthecardslivers
2.Tomakethem lieinamannerparalleltotheirneighborsandtothe
sliveraxis.
3.Toimprovetheuniformityandevennessofthesliversbydoubling
4.Toproduceamoreuniformsliverofdefiniteweight/unitlength.
5.Toreduceweightperunitlengthofsliver
6.Toremovedustfromsliver
7.Tomakeperfectmixing/blendingofthesliver
Tasksofdrawframe:
1.Equalizing:oneofthemaintasksofthedraw frameisimproving
evennessovershort,medium andespeciallylongterm variation.
Equalizingisalwaysperformedduringdrawingbyafirstprocess
namelydoublingandcanoptionallyalsobeperformedbyasecond
processnamelyautolevelling.Thesliversfedtothedrawframefrom
thecardcontainsvariationsinthicknessthatistheyarenotregular.
Thedoublingprocessindrawframeimprovetheregularityofthefinal
sliverbyaveragingouttheweightvariationsexistinginsliversfedto
drawframe.
2.Parallelizingandstraightening:Toobtainoptimum strengthinyarn,
thefibersmustbearrangedparallelinthefibersstrand.Thedraw
framehasthetaskofcreatingthisparallelarrangement.Itfulfilsthis
taskbythewayofthedraftsinceeverydraftingstepleadsto

4. straighteningofthefibers.
3.Blending:Thoughablendingcanbeachievedinmodernblowroom
process,furtherblendingaftercardimprovesthecompositionof
fibersinthesliver.Thepracticeoffeedingseveralslivers(doubling)
sidebysidethroughthedraw frameandrecombiningthem atthe
frontgivesaverygoodblendingoffibersintheindividualsliverand
thismakesthefinalslivermoreuniform thancardsliverinfiber
composition.
4.Dustremoval:Thedraw frameisagooddustremovingmachine
becausetherearehighlevelsoffibertofiberandfibertometal
frictionduringdrafting.Onhighperformancedrawframesequipped
withappropriatesuctionorremovalsystem morethan80% ofthe
incomingdustisextracted.
Q.whatistheinfluenceofdoublingonsliverquality?
Q.whatistheinfluenceofdraftingonsliverquality?
Definitionofdifferentterms:
1.Drawing:Aprocessinshortstaplespinninginwhichthesliversare
blended,doubled,levelledanddraftedbypassingthesliversthrough
aseriesofpairsofrollerseachpairmovingfasterthantheprevious
one.
2.Doubling:Theprocessofcombingtwoormoreslivers,rovingsor
yarnsintooneiscalleddoubling.
3.Drafting:Theactionofreducingtheweight/unitlengthofthefeed
materialbydrawingisknownasdrafting.
4.Creelinganddoffing:Theoperationofreplacingthecansoffeed
materialatthebackofthemachineandjoiningthenewcanfullof
slivertotheoldisknownascreelingandthatofremovingthefull
deliverycansfromthefrontofthemachineisknownasdoffing.
Featuresofmoderndrawframe:
1.Eliminationofmechanicalcausesofirregularity.Provideselectrical
controlautolevellingwhichgivesandmaintainshigherdegreeof
regularityindrawnsliver.
2.Highspeedrunning

5. 3.Pneumaticsuctiondevicesfordustremoval
4.Stopmotionsatstrategicpointstostopthemachinewhenneeded
5.Automaticcanchangers
6.Moremachinesperoperativeandlittleattentionneeded.Soreduces
laborcost
7.Improvedtoparmweightingsystem
Elementsofdraftingarrangement:
Bottom roller:Bottom rollersaremadeofsteelandaremountedinroller
strandsorinframesbymeansofneedleorballbearings.Theyare
positivelydrivenfrommaingeartransmission.
Onordertoimprovetheirabilitytocarrythefibersalong,theyareformed
withflutesofoneofthefollowingtypes.
a) Axialflutes
b) Spiralflutes
c)Knurledflutes
Toproller:Thetoprollersarenotpositivelydriven;theyaremountedbythe
meansofballbearings.Thesetoprollersaremadeofsteelandtheyare
coveredwiththickcoatingofsyntheticrubber.Animportantmatteravoid
thiscoatingisitshardness.Softrubberscoatingcangripthefiberstrand
moreperfectlythanthatofhardone,butsoftcoatingofrubberwearout

6. morequickly.
Hardnessofrubbercoatingontoprollersisspecifiedintermsofdegree
shore.
Softcoating->60-70degreeshore
Mediumcoating->70-90degreeshore
Hardcoating->Above90degreeshore
Toprollerpressure:Toclampthefibers,thetoprollersmustbeforcedout
athigh pressure towards the bottom rollers.This pressure can be
generatedby:
1.Loadingbymeansofdeadweight(nowobsolete)
2.Springweighting(themostusualform)
3.Hydraulicsystems(hardlyused)
4.Pneumaticweighting(theRietercompany)
5.Magneticweighting
Typesofdraftingarrangement:Earlydrawframeshadalmostexclusively4
over4rollerdraftingsystems.The3over4rollersystem wasdeveloped
outofthisearlierversionandthereafteramultitudeofnewformsemerged.
The drafting system maybe classified based on the form ofroller
arrangementcanbedescribedbelow:
1.Conventional4over4rollerdraftingsystem
2.3over4rollerdraftingarrangement
3.3over3rollerdrafting
4.4over3rollerdrafting
5.5over4rollerdrafting
4over3rollerdraftingarrangement:Thisisthemostwidelyuseddrafting
arrangementfordraw frames.Strictlyspeaking,thisisalsoa3roller
pressurebardraftingarrangementbutafourthrollerwithsomewhatlower
loadingisaddedtothedeliveryrollertoactasaguide.Thisleadstheweb
incurveroundthegroovedrollerdirectlyintothedeliverytrumpet,thereby

7. facilitatingtheformationofthesliver.Thetoprollersareuniform in
diameterandarelargeinordertokeepthestrainimposedinthemlow.
Draftcalculation:let,backrollerrpm=500&diameter=30mm
Middlerollerrpm=900&diameter=30mm
Frontrollerrpm=3000&diameter=40mm
Weknow,draft=
surfacespeedoffrontroller
surfacespeedofbackroller
= (surfacespeed=πdn)
3.1416×40×3000
3.1416×30×500
=8
Backdraft=
surfacespeedofmiddleroller
surfacespeedofbackroller
=
3.1416×30×900
3.1416×30×500
=1.8
Frontdraft=
surfacespeedoffrontroller
surfacespeedofmiddleroller
=
3.1416×40×3000
3.1416×30×900
=4.44
Totaldraft=backdraft×frontdraft
=1.8×4.44
=8

8. Requirementsofdraftingarrangement:
1.Simple,uncomplicatedconstruction
2.Stabledesignwithsmoothrunningoftheroller
3.A modeofoperationgivingahighqualityproductevenathigh
runningspeed
4.Highdegreeofflexibility(suitabilityforallrawmaterial,fiberlength,
sliverwt.)
5.Rapidandsimpleadjustabilityofrollerspacing
6.Rapidandsimpleadjustabilityofdraftlevel
7.Easeofmaintenanceandcleaning
Q.whatdoyoumeanbyrollersetting/rollerspacing/rollergauge?What
istheimportanceofrollersettingondraftingarrangement?
Answer:Inadrawframeitisnecessarytospacetherollersacertain
distanceapart.Thedistancefrom thecentreofonerollertothecentre
ofanotherisknownastherollersetting/rollerspacing/rollergauge.
Rollersettingmainlydependsonthestaplelengthoffiber.Iffiberstaple
lengthishighthenrollersettingmustbewide.Ontheotherhandiffiber
staplelengthislowthenrollersettingmustbeclose.
Factorsdependinguponthedraftingarrangement:
1.Diameteroftherollers
2.Hardnessoftoprollers
3.Pressureexertedbythetoprollers
4.Surfacecharacteristicsoftoprollers
5.Rollersetting/rollerspacing/rollergauge
6.Levelofdraft
7.Distributionofdraftbetweenvariousdraftingstages
Q.1. Adraw frameisrunningwith4-over-4draftingsystem.Please
distributethedraftbetweenvariousdraftingstages.(Sufficientdatawill

9. begiven)
2.A draw frameisrunningwith4-over-3draftingsystem.Please
distributethedraftbetweenvariousdraftingstages.(Sufficientdatawill
begiven)
Necessitiesofautostopmotion:
1.Thesliverrunoutfromthecreeledcan
2.Sliverbreaksinthecreel
3.Lappingupondraftingrollers
4.Ifsliverislappingbetweentrumpetandcalendarroller
5.Ifdeliverycanisfilledwithsliver
Ifautostopmotionisabsent:
1.Considerabledamagemaycausetomachine
2.Theoutputslivermaybethickorthin
3.Lappingupofdraftingorcalendarroller
4.Irregulardrafting
5.Excessoffullcan
6.Toomuchwasteproduce
7.Theyarnstrengthorrovingstrengthmayvaryfromplacetoplace
8.Anyoperatormusthavetoattendthemachinefulltimetostopitat
anyfault
Autolevelling:Autolevellingisanadditionaldevicewhichismeantfor
correctingthelineardensityvariationsinthedeliveredsliverbychanging
eitherthemaindraftorbackdraftofthedraftingsystem,accordingto
thefeedvariation.
Therearetwotypesofautolevellingsystems:
1.Openloopsystem
2.Closedloopsystem
Openloopautolevelling:Inopenloopautolevelerssensingisdoneat
thefeedingendandthecorrectionisdonebychangingeitheraback

10. draftormaindraftofthedraftingsystem.Mostofthedrawframeauto
levellersareopenloopautolevellers.
Closedloopautolevelling:Inclosedloopsystem,sensingisatthe
deliverysideandcorrectionisdonebychangingeitherabackdraftor
maindraftofthedraftingsystem.Mostoftheearliercardautolevellers
areclosedloopautolevellers.Butthelatestcardshavesensingatthe
feedrollersandaswellasatthedeliverycalendarrollers.Wecansay,
bothclosedloopandopenloopsystemsarebeingusedinsuchauto
levellers.
Letusdiscussaboutanautolevellersystem whichisbeingusedin
mostsuccessfuldrawframeslikeRSB-951,RSB-D-30etc.
Thissystem isanelectroniclevellingsystem.Themajorcomponentsin
thesystem arescanningroller,signalconverter,levellingCPU,servo
motor,Differentialgearbox.Function ofthe scanning rolleris to
measurethevariation inthefeedmaterial.Allsliversfedtothemachine
passthroughapairofscanningrollers.Oneofthescanningrollersis
moveableandanotherisfixed.
Thevariationsin slivermassoftheincoming sliversdisplacethe
scanningroller.Thedistancemovedbythescanningisproportionalto
the sliver mass fed. This displacement of scanning rollers is
transformedintovoltagebyasignalconverterandisfedtoanElectronic
Levelling processor.Itis the Electronic Levelling processorwhich
furnishesthecorrecttargetvaluetotheservomotor.

11. Deliveryspeedofthemachineandelectricsignalvaluesarrivedatby
theslivers fedarethetwoimportantsignalsforthecorrection.Servo
drivetakestheinformationandisconvertedinsuchawaythatservomotor
RPM and direction is decided forappropriate correction.Differential
gearingwithitscontrolledoutputspeeddrivesthemiddleandbackroller.
i.e.Sliverentryofthedraftingsystem.BecausetheservomotorRPM and
direction variesaccording to thefeed variation and theservo motor
generatesacontrolspeedofthedifferentialgearing,therequiredchangein
maindraftisaccomplished,compensatingfortheweightvariationofthe
sliverfed.
 Ifthesliversfedaretooheavy,theentryspeed(backandmiddle
rollerspeed)isreducedi.e.draftincreased
 Ifthesliversfedaretoolight,theentryspeedisincreasedi.e.draft
reduced
Deliveryspeed(thefrontrollerspeed)remainsconstantandhencethe
productionremainsconstant.
Mathematicalproblem:
1.Findoutthedraftofadrawframeifcardsliverwt.is70gr/yd,drawn
sliverwt.is75gr/yd,doublingratiois6:1.
2.Iffrontrollerrpmis5000anddiameteris40mmthenwhatwillbethe
deliveryspeedofthisdrawframe?
3.Findouttheproduction/hrinkgofadrawframeiffrontrollersurface
speed650m/min,drawnsliverwt.75gr/yd,efficiency90%.
4.Ina4over3draftingsystem,speedofbackrolleris500,diameterof
backrolleris35mm andtotaldraft8.45.Ifdrawnsliverwt.is75
gr/ydthenwhatwillbetheproductioninkg/hr.letefficiency90%.
5.Let,countofinputsliver72gr/yd,doubling,totaldraftandfrontroller
surfacespeedwereset8,8.7and700m/minrespectively.Findout
theproduction/dayofthisdrawframe.(efficiency88%).
6.Let,countofinputsliver70gr/yd,doublingratio8:1,backdraft1.8,
frontdraft4.4,backrollerrpm 500,diameterofbackroller30mm.
findouttheproduction/dayofthisdraw frame.Assumeefficiency
92%.