spun-yarns.pdf

SpunYarns

Copyright20082011NorthCarolinaStateUniversity.Allrightsreserved.

Slide1

SpunYarns

Thispresentationintroducestheprocessofmanufacturingspunyarns.Thecharacteristicsandclassificationsforspunyarns,howtheyarnsarenumbered,detailsconcerningeachstepinthemanufacturingprocess,thedifferentpropertiesperyarntype,theimportanceoftwistandtwisteffects,noveltyandspecialtyyarns,andyarntestingwillbediscussed.

SpunYarns


Slide2

CharacteristicsofSpunYarns Composedofshortstaplefibersandlongstaplefibers. Madefromcotton,flax,orwoolstaplefibers. Madefromnaturalormanmadefilaments,whicharecutintofilament

staple. Individualfiberlengthsmayvary. Hairyorfuzzyappearanceandfeel. Unevennumberoffibersthroughout. Canrangefromsoft,looseconstructiontohard,finetwistyarn. Inherentthickandthinareas. Fallsapartwhenuntwisted. Lowerlusterthanfilamentyarns. Naturaltexturalappearanceandfeel. Providesgoodcoveringpower Pillingdependsonfibercontent.

Spunyarnscanbecomposedoffibersthatarerelativelyshort,onefourthtotwoandonehalfinchesinlength,orfibersthataregreaterthantwoandonehalfinchesinlength,typicallynotexceedingeightinches.Theseyarnscanbemadefromnaturalandmanmadefibersthatfitthelengthrangesdescribed.Individualfiberlengthswithinagivenyarnmayvary.Spunyarnsexhibitahairyorfuzzyappearance.Alongthelengthoftheseyarns,therewillbeanunevennumberoffibersintheyarncrosssection.Dependingupontheamountoftwistinserted,spunyarnswillvaryfromacoarse,soft,andlooseconstruction,toafiner,harderconstruction.Spunyarnsinherentlycontainthickandthinareasalongtheyarnlength.Whenuntwistedtheyarnwillfallapartandtheshortorstaplefiberscanbepulledout.Theseyarnshavealowerlustercomparedtofilamentyarnsandhaveanaturaltexturalappearanceandfeel.Theinnateyarnhairinesshelpstoprovidegoodcoveringpowerinfabrics.Thetendencyforcertainyarnstogeneratelittleballsofentangledfiberscalledpillswillgenerallydependuponthefibercontent.

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Slide3

YarnClassifications

Spunyarnsaregenerallyclassifiedaseithershortstapleorlongstaple.Shortstapleyarnscontainfibers2.5inchesandshorterwhilelongstapleyarnscontainfibersgreaterthan2.5inchesinlength.Thegeneralyarntypesundereachclassificationcanbeseeninthisdiagram.Thefocusofthispresentationisuponshortstapleyarntechnology.Thisincludescardedversuscombedshortstapleyarn,singleversuspliedyarns,andacomparisonofthemethodsofspinningusedtoproducedifferenttypesofyarnsthatareshowninthediagram.Someshortstaplespunyarnsareclassifiedasnoveltyyarnswhichhavespecialeffectsbuiltintotheirstructure.

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Slide4

YarnNumber MeasureofthelineardensityofayarnandNOTthe

diameterorcrosssectionalsizeoftheyarn. Expressedasacertainlengthofyarnperastandardweight

orasacertainweightofyarnperastandardlength. YarnCountandYarnSizearesynonymouswithYarn

Number

Sinceyarnnumberisanexpressionofaratioithasnounits

Oneofthemostimportantcharacteristicsofanyyarnisthelineardensityoftheyarnreferredtoastheyarnnumber.Spunyarnsarenumberedsothatonecanchooseayarnofrelativethicknessthatmaybeneededforaparticularfabricapplication.Thisnumberisnotthediameteroftheyarnorcrosssectionalsizebutratherthelineardensitywhichisnormallyexpressedasaratioofagivenlengthofyarnperastandardweightorasacertainweightofyarnperastandardlength.

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Slide5

YarnNumberingSystems

Whenyarnsarenumberedusingtheindirectnumberingsystem,highernumbersdesignatefineryarnsandlowernumbersdesignatecoarseryarns.Whenyarnsarenumberedusingthedirectnumberingsystem,highernumbersdesignatecoarseryarnsandlowernumbersdesignatefineryarns.TheyarnsinthisphotographarenumberedontheEnglishcottoncountsystem.Thissystem,metriccount,worstedcount,andwoolenrunareallindirectnumberingsystems.Themostwidelyuseddirectnumberingsystemsaredenier,tex,anddecitex.

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Slide6

MajorIndirectNumberingSystemsEnglishCottonCount(Ne) yarnnumberrepresentsthenumberof840yardlengths(hanks)ofyarnthatweighonepoundExample:aNe24yarnnumbermeansthatittakes24hanksoftheyarntoweighonepound 24/1denotesasinglesyarn(24singles) 48/2denotesapliedyarn(48s2ply)Question:Whatdoes10/1mean?

WhenusingtheEnglishcottonsystemdesignatedbyNe,theyarnnumberrepresentsthenumberof840yardlengthsofyarnthatittakestoweighonepound.Sometimesthisstandard840yardlengthiscalledahank.Thus,ifittakes24hanksor24840yardlengthsofyarntoweighonepound,theyarnnumberwouldbe24.A48s2plyyarnisequivalenttoa24ssingleyarnandwouldrequire24hanksofthatyarntoweighonepoundaswell.Sowhatdoes10/1mean?Theanswerisonepoundofa10/1yarnwouldhaveayarnlengthof10hanksor8,400yards.

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MajorIndirectNumberingSystemsMetricCount(Nm) yarnnumberrepresentsthenumberofmeters(orkilometers)ofyarnthatweighonegram(orkilogram)

Example:aNm30yarnnumbermeansthatittakes30metersofyarntoweighonegramor30kilometersofyarntoweighonekilogram

Question:WhatdoesNm20mean?

Metriccount,designatedasNm,isusedfrequentlyinEuropeandAsiawiththeyarnnumberrepresentingthenumberofmetersofyarnthatweighsonegramorthenumberofkilometersofyarnweighingonekilogram.Forexample,a30Nm(metric)yarnweighingonekilogramwouldbe30,000metersinlength.Whatdoesa20smetricyarn(nm)mean?Theansweris20kilometersoftheyarnwouldweighexactlyonekilogram.

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Slide8

MajorIndirectNumberingSystemsWorstedCount(Nw) yarnnumberrepresentsthenumberof560yardlengthsofyarn(alsocalledhanks)thatittakestoweighonepound.Example:aNw 36yarnmeansittakes36560yardlengthsofyarntoweighonepound.Note:Worstedcountyarnsareusuallylongstapleyarnsandtypicallywoolorwoolblendsthatgointoworstedfabrics.

Theworstedsystem,designatedbyNw,usesastandardhankof560yardsratherthan840asusedintheEnglishcottoncountsystem.ThereforeaNw36worstedyarnweighingonepoundwouldbe36hanksinlength(36x560yards)or20160yards..Longstapleyarnscontainingfibersgreaterthan2.5inchesinlengthareusuallynumberedontheworstedsystemintheUnitedStatesandEnglandandareusedinthemanufacturingofworstedfabrics.

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Slide9

MajorDirectNumberingSystemsDenier yarnnumberrepresentstheweightingramsof9,000metersofthegivenyarnExample:a70denieryarnweighs70gramsperastandardlengthof9,000metersExample:a300denieryarnweighs300gramsper9,000metersQuestion:Whatdoes150deniermean?

ThedenieryarnnumberingsystemiscommonlyusedaroundtheworldandoriginatedinFrance.Thedenieryarnnumberrepresentstheweightingramsof9,000metersofagivenyarn.Thusa70denieryarnmeansthat9,000metersofthatyarnweighsexactly70grams.A300denieryarnwouldbemuchcoarserandthereforeweigh300gramsperastandardlengthof9,000meters.Whatdoes150deniermean?Theansweris9,000metersoftheyarnweighs150grams.

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Slide10

MajorDirectNumberingSystemsTex yarnnumberrepresentstheweightingramsof1,000metersofyarnExample:a20tex yarnweighs20gramsperastandardlengthof1,000meters

Decitex (dtex) yarnnumberrepresentstheweightingramsof10,000metersofyarnExample:a200decitex yarnweighs200gramsper10,000meters

Thetexyarnnumberisbasedupontheweightingramsofyarnperastandardlengthof1,000meters.Thus,a20texyarnweighs20gramsperstandardlengthof1,000meters.Decitexisbasedonastandardlengthof10,000metersandthusa200decitexyarnweighs200gramsper10,000meters.

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YarnNumberConversionsSome CommonConversions:Nm/1.69=Ne5314/Denier=Ne590.54/Tex=NeDenier/9=TexDecitex /10=TexNw /1.5=Ne

Alistofcommonyarnnumberingconversionsusedinthetextileindustryisgiveninthisslide.Individualsoftenconverttothesystemwithwhichtheyfeelmorecomfortable.WhatNeyarnnumberwouldbeequivalentto32Nm?Theconversionequationsasseeninthisslideindicatethattoconvertametricyarntoanenglishcottoncountyarn,dividethemetricyarnby1.69.Answer:321.69=19

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Slide12

ProcessingtheMajorYarnTypesRingSpunCardedYarnRingSpunCombedOpenEndCardedAirJetCardedVortexCombed

Themajorspinningprocessesusedtomanufactureshortstaplespunyarnsarelistedinthisslide.Yarnsproducedusingthesedifferenttypesofspinningmachinesvaryastoprocessingsteps,productivity,automation,physicalproperties,andenduses.

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Slide13

RingSpunCardedYarns

Thesequenceofprocessesforconvertingastaplefiberintoaringspuncardedyarnareshowninthisdiagram.Fibersarepluckedfrombalesanddeliveredtoopeningmachinerywhichseparatesthefibers,removesheaviertrashparticles,andprovidesblendingopportunities.Cardingconvertsfibersintoacontinuousstrandcalledsliver.Multiplecardsliversthenfeedintooneormoredrawingprocesseswhichimprovesliverquality.Drawingsliveristhenconvertedintorovingwhichisapencilsizedstrandoflightlytwistedfibers.Therovingisfedintoringspinningmachineswheretheyarnisformed,placedontosmallbobbins,andtransportedtowindingmachines.Atwinding,theyarniswoundontoconesortubestoformalargeyarnpackagetobeusedinweavingorknittingoffabrics.

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CombedRingSpunYarns

Tomanufacturecombedringspunyarn,anadditionaldrawingprocessisaddedaftercardingfollowedbyalapwindingprocess.Thenthecombingoperationfollowslapwinding.Adrawingprocessisneededaftercombinginordertoreducevariationintroducedbythecombingprocess.Itiseasytospeculatehowaddedprocesses,labor,andtimeraisesthecostofcombedyarnscomparedtocardedyarns.

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Slide15

OpenEndRotorYarns

Whenreviewingthediagraminthisslideitiseasytodeterminethattheopenendorrotorspinningsystemrequiresfewermanufacturingstepsthantheringspinningsystem.Whatprocessesareeliminatedwhenmanufacturingopenendcardedyarncomparedtoringspuncardedyarn?Manyoperationsonlyuseonedrawingstepinsteadoftwo.Someplantsutilizeadrawboxonthecardingmachineandeliminateaseparatedrawingoperationaltogether.Thewindingprocessisincludedinthespinningmachineanddoesnothavetobeaseparateoperationasinthemakingofringspunyarnandnorovingisneededinspinningopenendyarns.Productivityofanopenendspinningmachineis8to10timeshigherthanthatofaringspinningmachine.

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Slide16

AirJetSpunYarns

Typicallythreedrawingstepsareusedtomanufacturegoodqualityconventionalairjetyarn.Again,norovingisneeded,andwindingisincludedontheairjetspinningmachine.Theproductivityofanairjetspinningmachineis20to22timeshigherthanaringspinningmachine,andtwiceasfastasopenendspinningmachine.

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Slide17

VortexSpunYarns

ThelatestmethodofairjetspinningiscalledVortexSpinningwherelapwindingandcombing,alongwithdrawingbeforeandaftercombing,aretypicallyincludedintheprocessflow.Windingisalsoincludedonthevortexspinningmachine.

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Slide18

ProcessKnowledge Detailedinformationabouteachstepintheprocessingofthedifferenttypesofshortstaplespunyarnwillnowbeprovided.

Eachstepcanbethoughtofasasupplierforthenextstepwhocanbeconsideredthecustomer.Eachstepwillhaveuniqueobjectivesintheprocesschain.

Detailedinformationabouteachstepintheprocessingofthedifferenttypesofshortstaplespunyarnwillbediscussed.Eachstepcanbethoughtofasasupplierforthenextstepwhichcanbeconsideredthecustomer.Eachstepwillhaveuniqueobjectivesintheprocesschain.

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Slide19

Theopeningroomareaofashortstapleyarnmanufacturingfacilityhasthreecriticalobjectives:fiberopening,cleaning,andblending.Therawmaterialorfiberisdeliveredtotheopeningroomintheformofhighlycompressedbalesoffiberweighingfrom400to550pounds.Thebalesoffibermustbearrangedintoabalelaydown.Thebalelaydownisformulatedbaseduponfiberproperties.Whenfeasiblethebalesareproperlypreparedandconditionedforapproximately24hourspriortouse.Thestockmustbeprogressivelyopenedintosmallerandsmallertuftstopreventfiberdamage,topromotebettercleaning,andtoenhancetheblendofthestock.

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Slide20

BaleLaydownandTopFeeder

Eachspunyarnmanufacturingfacilitybeginswithalaydownoffiberbales.Mostbalelaydownscontainfrom30to80balesoffiber.Asseeninthisphotograph,arobotcalledatopfeedermovesconstantlybackandforthoverthebalelaydown,extractingathinlayeroffibertuftsfromeachbale.Thisistheinitialopeningofthefibersfromthehighlycompressedbales.Theextractedfiberisinturnfedintotheopening,cleaning,andblendingmachines.Eachlaydowntypicallylastfrom12to24hours.Generallytherewillbealaydownoffiberbalesforeachopeninglineinamanufacturingfacility.Somelaydownsmaycontainbalesofcottonorsomeothernaturalfiber,whileotherlaydownsmightcontainbalesofsyntheticfibers.

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Slide21

EFS

MostcottonlaydownsinmodernplantsarecomputergeneratedforEngineeredFiberSelection.OneofthemostcommontoolsusedtoselecttheappropriatebalesforalaydownistheEFSsystemdevelopedandpromotedbyCottonIncorporated.TheworkstationconsistsofaPC,modemorinternetconnection,labelprinter,andbarcodereader.Individualmillsselectthemostimportantfiberpropertiesthattheywanttocontrol.Eachbaleoffiberislabeledwithspecializedtagsdefiningitsfiberproperties.Balesarethenplacedinspecificplacesinthewarehouse.EFSsoftwaredesignsalaydownbasedonthemaximumnumberofbales,therequiredfiberqualities,andthecoefficientofvariationinthewarehouseinventory.Dependingonthenumberoflaydownsrequiredinthemill,multiplemixselectionscanbemadefromthesamebaleinventory.Normallytheaverageandcoefficientofvariation(CV%)for34fiberpropertiesarestrictlycontrolledfromlaydowntolaydown.

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Slide22

IdealLaydown Minirepresentationofoverallcottonbaleinventory

Thisallowsduplicationoflaydownsascloseaspossiblefromdaytoday,weektoweek,andmonthtomonth

Resultingyarncharacteristicswillbemoreconsistent.

Theideallaydowninayarnplantwillbeaminirepresentationoftheoverallcottonbaleinventory.Thus,iftherearemanybaleswithacertainmicronaire,representingcottonfiberthickness,thentherewillbeaproportionatenumberofbaleswiththatsamemicronaireinthelaydown.Whenthisprocedureisfollowed,aduplicationoflaydownsoccursleadingtoamoreconsistentyarnqualityandyarncharacteristicsovertime.

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Slide23

TopFeederOpeningRollersVideo

Thisvideohighlightstheopeningrollersonthetopfeeder.Wheninoperation,theheadlowersslightlyintothebalesurfacesandplucksathinlayeroffibersfromeachbale.Thussmall,partiallyopenedtuftsoffiberswillberemovedandfedtotheopeningline.

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TopFeederAnimation

Noticethatthetoothedopeningdisksrollersrotateinoppositedirectionstooneanother;onewillbeengagedandtheothernotinoperation,dependingonthedirectionofmovementofthetopfeeder.Thisarrangementpromotesmoregentleandprogressiveopeningoffibertufts.

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CoarseOpeningMachineAnimation

Anopeninglineofmachineryfollowsthebalelaydownandtopfeeder.Itiscomprisedofaseriesofmachinestoprogressivelyopen,clean,andblendthefiberswithoutseriouslydamagingthem.Thefirstmachineinanopeninglineisgenerallyacoarsecleanerdesignedtoremoveheavytrashparticlesfromcottonandothernaturalfibers.Whenworkingwithsyntheticfibers,thistypeofmachineisomittedsincethefibersarefreeofwastematerial.Thebeateronacoarsecleanerusuallyconsistsofmetalfingerswhichmovethefibersoveraseriesofgridbars.Gridbarsareeithermanuallyadjustedorcontrolledbyaservomotorsothattheamountofwastecanbecontrolledincombinationwiththespeedofthebeater.Asgridbarsaresetwider,morewasteisremovedandalsomoregoodfiberisremoved.Thesetypemachinesusemechanicalaction,air,andcentrifugalforcetoopenorseparatethefibers.Thisopeningpromotesbettercleaning,transporting,andseparationofthefibers.

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FineOpener/Cleaner

Incontrasttothecoarseopeningandcleaningmachineshownpreviously,thefineopenerandcleanerisdesignedtoopenfibersintoverysmalltuftsandremoveveryfinetrashparticles.Itisnormallylocatedattheendoftheopeninglinepriortothefibersbeingfedintothecardingmachines.

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Slide27

MulticellBlendingMachines

Afteropeningandcleaningoftextilefibers,thethirdobjectiveoftheopeninglineisblending.Whenblendingfibersofthesametype,thegoalistoreduceproductvariationsduetothevariabilityoffiberproperties.Whenblendingmultipletypesoftwoormorefibers,thegoalistoproduceamorehomogeneousblend.Goodblendingprinciplesandpracticesproducebetterqualityyarnandmoreuniformlydyedfabrics.Seeninthisdiagramisatypicalblendingmachinewithamultiplenumberofcellsorchambersoperatingonatimedelay.Fiberscomeintothemachinecellsinageneralflow,andaredistributedintodifferentcellswhichallowsthefiberstotravelatdifferentratesuponexitingthemachine.Thusthefibersexitthemachineasabettermixorblendcomparedtotheirinitialstatepriortoblending.

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Slide28

BlendingMachineAnimation

Inthisanimationofablendingmachine,thedifferentcolorsoffiberscomefromdifferentbalesinthelaydown.Thefibersinthecellfurthesttotherighttakelongertotravelthroughthemachinewhencomparedtothefibersinothersuccessivecells.Thistimedelayprincipleaidsinbetterblendingoffibersandfiberproperties.Ideally,allthecellsshouldbeequallyfilledwithfibers.Thesemulticellblendersareverycommoninspunyarnplants.

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Slide29

IntimateBlending

Whenblendingdifferenttypesoffibers,itisnecessarytoinitiallycontroltheblendpercentageofeachfibertype,forexample65%polyesterand35%cotton.Whenprocessedintheopeningroom,itisreferredtoasanintimateblend.Acommonwayofproducingintimateblendsistousehoppersandweighpans.Fourhoppersareseeninthisdiagram.Threeofthesearebeingfedwithvirginfiberandoneisusedtofeedrecycledfibers.Eachhoppermaycontainadifferentfiberwhichisplacedintoaweighingpanwhichcontrolsthatfiberspercentageinanoverallblendwithotherfibers.Eachweighingpancanbeelectronicallysettodropacertainweightoffibersontoaconveyorbeltwhichmovesforwardaftersimultaneousdropsofthedifferentfibertypes.Asandwichblendisthusformedandthelayersoffibersthenenterabeaterwhichfurthermixesthemtogether.

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Slide30

OpeningMachineLatticeFeedAnimation

Intimateblendlinehopperscanbehandfedorautomaticallyfedthroughductwork.Mosthoppershaveahorizontalapronorconveyorsystemfortransportingfibertuftsforwardontoaverticalapron.Theverticalaproniscomposedofawoodenormetallatticecoveredwithwirepins.Thepinspenetratethefibertuftsandtransportthemupwardtoarotatingroller.Therollerkicksbackthelargertuftsoffibers,recyclingthemuntiltheyarethoroughlyopenedintosmallertufts.Thusthefibertuftsareopenedandprogressivelydiminishedinsize.Thistreatmentofthefiberspreventsoverworkingwhichcouldresultinfiberdamage.Thisactiondeliverswellopenedandsmalltuftsoffiberintothefrontareaofthehopperwhereweighpansarelocated.

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Slide31

OpeningMachineLatticeFeedVideo

Theactionsofaverticalaproninanopeningmachinecanbeseeninthisvideo.Noticethatthelargertuftsoffibersarerecycleduntiltheyaresmallenoughtopassthroughthemachine.

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Slide32

WeighPanOperationVideo

Thisvideoshowsaweighpaninoperation.Thisparticularblendlineonlyhastwoweighpans,whilemanyblendlineshave6to8.Theweighpanshownintheinitialpartofthevideoisopenforcontinuousoperation.Inthiscasethefibersarenotbeingweighedtoaccomplishapredeterminedblendratio.Whencontrollingthepercentageoffiberstobeblended,themachinewouldelectronicallyweighaprescribedamountoffiberandthendropthatweightoffiberontoaconveyorbelt.Theotherweighpanswouldbecollectingpredeterminedweightsofotherfibersanddroppingthemontothesameconveyor.Itisaslowprocessbecauseoftheintermittentstoppingandstartingwhilethefibersareweighed.However,whendyeinglightpastelshadesandothercriticalmultifiberdyeings,itisthepreferredmethodofblending.Lookingatthefeedsideofthemachine,asyntheticfibercanbeseenasitisbeingfedontoaverticallatticeapron.Thesefibersdidnothavetobecleanedbuthadtobeopenedpriortoarrivingattheintimateblendline.Theopeningorkickerrollinoperationcanbeseenthroughtheplexiglasswindow.Atthispointinthevideo,theweighpanisseeninaclosedpositionandthenopenedtodropasetweightoffiberontotheconveyorapron.Aseachweighpandropsadifferenttypeoffiber,asandwichoflayersoffibersisformed.Thedroppedfiberisthendirectedtoabeatersystemwhichmixesthedifferentfiberstogether.

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Slide33

Carding

Aftertextilefibersareopened,cleaned,andblendedtheyarefedtothenextprocesscalledcarding.Cardingutilizesmachinemechanismsthatallowforthetotalopeningofthefibers.Pointsofwirepenetrateamongindividualfibersgivingopportunitiesforanyfinetrashparticlesleftinthestocktoberemoved.Atthesametimethefibersarestraightenedtothepointtheyareparalleltoeachother.Fibersthathavebeenrolledintonepswillberemovedataveryhighrateofefficiency.Aropelikeassemblyoffiberscalledasliverisdeliveredfromthecardingmachinewithasetweightperunitlength.Thesliverwillbecoiledintoacylindricalcanreadyfortransporttothenextprocess.

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Slide34

MaterialFeedforCardingVideo

Thisvideoshowsathickmatoffibersbeingpulledveryslowlybyfeedrollsintothebackofthecardingmachine.Thematisformedinthecardchutewhichcollectsthefibersfromtheopeningline.Thematmustbeformeduniformlyandbefedinaconsistentmanner.

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Slide35

CardingDeliveryVideo

Thedeliveryofcardsliverfromacardingmachineisseeninthisvideo.Thedeliveredsliverisperiodicallytestedforproperweightandlevelofevennessaswellasfornepcountandshortfibercontent.Ithasbeensaidthatcardingisthemostimportantprocessinthemanufactureofspunyarn.Thesloganoftenusediswellcardedishalfspun.

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Slide36

CardingElements

Inacardingmachine,thefibersenterasamatorthickblanketandexitintheformofathinweb.Themachineiscomposedofrotatingcylinderscoveredwithdifferenttypesofwire.Thesurfacespeedofthewirecoveredcylindersincreasesfromtherearofthecardtothefront.Thisresultsinareductioninweightandthicknessfromthematstatetothewebstate.Inadditiontowirecoveredcylinders,thereisalsoaseriesofwirestripscalledflatsthatrotateontopofthecardingmachine.Themaincardingactiontakesplacebetweenthelargecylinderandthewireflats.Thefunctionsoftheflatsincludesremovingneps,andanytrashwhencardingnaturalfibers,andtoassistthecylinderinaligningthefibers.Fibersaretakenoffofthemaincylinderbythedoffer.Severalinchesoffiberonthemaincylinderareactuallycondensedintooneinchonthedoffer.Thedofferthendeliversacardwebthatiscondensedintoafibrousstrandcalledsliverwhichisweighedingrainsperyard.Itistheinteractionofthewiresurfaceswhichallowsthecardtoreachitsobjectivesoffiberalignment,nepreduction,finewasteremoval,andshortfiberextraction.

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Slide37

CardWebs

Cardwebsofapproximately40to44inchesinwidthareverythinassembliesofstaplefibersdeliveredfromcardingmachinesandcondensedintosliverform.Goodcardwebswillbeuniformindensityfromsidetosideandhavealowpercentageoffiberentanglementsknownasneps.Poorcardwebswillbelessuniformindensityandcontainahigherpercentageofneps.

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Slide38

YarnBoards

Thespunyarnsontheleftofthisphotographareuniformandcontainfewneps.Thewhitespecks,calledneps,shownintheyarnsontherightphotographaretheresultofpoorcardingpractices.

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Slide39

KnitFabricComparison

Thecorrelationbetweencardsliverqualityandfabricappearancecanbeseeninthisphotograph.Fabricknittedfromgoodqualitycardingwillalsobemoreuniformandcontainlessnepsasseeninthisfabriccomparison.

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Slide40

Nep ImpactonDyeing

Nepstypicallycontainimmaturecottonfiberswhichcontainlesscellulosecomparedtomorematurefibers.Theimmaturecottonfiberswilldyealightershadeduetothereducedamountofcellulosetoabsorbthedye.

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Slide41

ConceptofDraft Draftisaconceptusedincarding,drawing,combing,roving,and

yarnspinning. Draftcreatesadecreaseinweightperunitlengthofanassemblyof

fibersformingamat,sliver,roving,oryarn. Astheunitweightoftheproductisreducedduringdrafting,the

lengthofthedeliveredmaterialisincreased. Numbersusedtoindicatethedraftcanonlybemultipliedand

divided(notaddedandsubtracted)whilecalculatingthetotaldraftonagivenmachine.

Draftisaratio hasnounits.

Oneofthekeyconceptsusedinthemanufactureofspunyarnsisdraft.Thetermisapplicabletocarding,drawing,combing,roving,andyarnspinning.Draftingoccurswhentheinputproductisdeliveredwithadecreasedweightandanincreasedlength.Drafthasnounitsbutisdescribedasaratio.Oneratiocomparestheweightofthematerialfedintoaprocesstotheweightdeliveredfromthatprocess.Thesecondratiocomparestherateofdeliveryinaprocesstothefeedrateofthatprocess.Theresultingdraftnumberisalwaysgreaterthanone.Numbersusedtoindicatethedraftcanbeonlymultipliedordivided,notaddedandsubtracted,whilecalculatingthetotaldraftofagivenmachine.

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Slide42

SliverWeight Sliveristhedeliveredproductatcarding,drawing,and

combing.

Sliverweightistypicallydescribedassomanygrainsofweightperyardofsliver.However,sliverismanytimesweighedin3yard,10yardand100yardsamples.

Mostsliverswillweighbetween50and80grainsperyard. Onepound=7,000grains Oneounce=437.5grains(7000/16)

Sliverweightsareoftenusedindraftcalculations.Sliveristhedeliveredproductatcarding,drawing,andcombing.Itisnormallydescribedastheweightperyardofsliver,expressedingrains,eventhoughthesliverismanytimesweighedin3,10,and100yardsamplesfortesting.Mostsliversweighbetween50and80grainsperyard.Thereare7,000grainsinonepoundandoneounceisequivalentto437.5grains.

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Slide43

DraftatCarding Typicallyintherangeof80to140 Ifacardingdraftis100,thatmeansthatthesliverisdeliveredfromthemachine100timesfasterthanthecardmatisfed.

MaterialDraftistheratioofmaterialweightsfedanddelivered.

MachineDraftistheratioofmachinespeedsatdeliveryandfeed.

Thedraftatcardingistypicallyintherangeof80to140.Acardingdraftof100meansthatthesliverisdeliveredfromthemachine100timesfasterthanthecardmatisfedtothemachine.Therearetwotypesofcardingdraft:material,sometimescalledactualdraftandmachinedraft.Materialdraftistheratioofthesliverweightfedtothesliverweightdelivered.Machinedraftistheratioofmachinespeedatthedeliveryendtothemachinespeedatthefeedend.

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Slide44

CardingDraftExampleAcardingmachineisdeliveringan80grains/yardsliverwhilefeedingacardmatweighing18oz.peryard.WhatistheMaterialDraft?Solution:

MaterialDraft=WeightFed/WeightDeliveredMaterialDraft=18oz/ydx437.5grains/oz

80grains/ydMaterialDraft=98.4

Inthiscalculation,437.5grains/oz.istheconversionfactortoconvert18oz/ydintograinsperyard.Noticethedraftiswithintheexpectedrange.Ifyouweretoobservethecardingmachine,youwouldnotetheslivercomingoutofthecardingmachineatamuchfasterratethanthecardmatisenteringthemachine.Whenthecorrectdraftissetuponacardingmachine,thenthedesiredsliverweightisdeliveredtothenextprocess.

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Slide45

QualityToolsforCarding Millprocessedsamplescan

betestedforneps,length,shortfibercontent,seedcoatneps andmaturity

AFISinformationisinstrumentalinmachinerymaintenanceandoptimization

AFIS AdvancedFiberInformationSystem

OneofthekeyqualitytoolsusedforevaluatingcardsliverqualityistheUsterAFISTester.Itisagreattoolforassessingneplevels,fiberlengthdamage,shortfibercontent,seedcoatnepsandfibermaturity.Itisadevicethatisusedtomonitormachinemaintenanceandtooptimizethecardingprocess.

SpunYarns


Slide46

Drawing

Drawingistheprocessfollowingcarding.Severalcardsliversarefedintothedrawingprocessforthepurposeofimprovingfiberalignmentwiththeaidofrollerdraftingandweightuniformitythroughblendingofmultipleslivers.Thegoalistodeliversliverofproperweightandqualitytotherovingorspinningoperations.

SpunYarns


Slide47

DrawingOverviewVideo

Thedrawingprocessisshowninthisvideo.Indrawing,multiplesliversarefedintoadrawingmachine.Thesesliversarecalledendsandtypically68endsarefed.Themultipleendsofsliverpassthroughasetofdraftingrollers.Thisdraftingreducesthemass,inthiscase,of6sliversintojustonedeliveredsliverweighingapproximatelythesameaseachindividualsliverfed.Inotherwords,ifsixsliverseachweighing60grainsperyardwerefedintothedrawingmachineandthemachinedraftwas6theweightofthesingledrawnsliverwouldbe60grainsperyard.Thus,thedeliveredsliverisablendofthe6sliversthatwerefed.Occasionallyfeedsliverswillbedifferentfibercontentandtheresultwillbewhatiscalledadrawblend.Forexample,if3silversofcotton,each60grains,and3sliversofpolyestereach60grains,werefedtodrawingwithadraftof6,theresultwouldbea50/50polyester/cottonblendsliverwith60grainsperyard.Thedrawblendwillnotbeashomogeneousastheintimateblenddiscussedearlier.However,thedrawblendismoreeconomical.Thetypeoffinishedproductanddyeingofthefinishedfabricfrequentlydictatetheuseofanintimateblendversusadrawblend.

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Slide48

FinisherAutoleveller Video

Inamanufacturingplantwheremultipledrawingprocessesareutilized,thefirstdrawingstageiscalledbreakerdrawingandthelastdrawingstageiscalledfinisherdrawing.Anautolevelleristypicallyusedonlyonfinisherdrawingmachinesandisplacedbetweenthecreelandthedraftingrollers.Itsensesweightvariationsinthefeedsliversandadjuststhemachinespeedstoproduceasinglesliverwithlessvariation.Allthecreeledsliversjointogetherandpassthroughtheautolevellerwhichisatongueingroovemeasuringunit.Thisunitiscomposedofsensororscanningrolls.Thesmallersensorrollmoveseversoslightlyaccordingtothickandthinplacesintheslivermassandasignalissenttothedraftingrollstomakethenecessarychangesindraftinordertomaintainconsistentsliverweightandevenness.

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Slide49

DraftingRollersAnimation

Thisanimationillustratestheprogressiveincreaseinthespeedofthedraftingrollersassliversmovefromthebackrollerontheleft,throughthemiddleroller,andfinallythroughthefrontrollerontheright.Thesmallarrowsonthedifferentrollersshowthatthefrontrollersarerotatingfasterthanthemiddleandbackrollers.Thisincrementalincreaseinrollerspeedscausessliverstoslidebyoneanother,resultinginareductioninmassofsixsliversintoamassofonesliver.Thesliverdeliveredistypicallyreducedinmassbyafactorof4to8times.Thusthesingleoutputsliverisdelivered48timesfasterthanthe6inputsliversbeingfedthroughthebackdraftingroller.

SpunYarns


Slide50

DrawingRollersVideo

Thisvideofollowssixendsofsliverastheyarepulledfromslivercans.Sliveriscoiledinthecanssoremovalwillbegentleandtensiononthesliverwillbeminimal.Thecreelareamustbekeptfreeoftagsorcollectionsofsheddingfibers.Thesliversmoveunderliftingrollerswhichdetectwhenaslivermaybemissingandinitiateamachinestop.Thefactthatanautolevellerisabsentfromthismachineindicatesthatitismostlikelyabreakerdrawframe.Thesixsliversthenmovethrougha3over3rollerdraftingsystem.Thetopthreerollersarerubbercovered,andthebottomthreearesteelandtypicallyfluted.Themetalexittubeinfrontofthedraftingrollerscontainsthesingledeliveredsliver.Closeobservationshowsthedifferenceinthespeedsoftherollers.Thespacebetweenthebackrollerandmiddlerolleriscalledthebreakdraftzone.Thespacebetweenthemiddlerollerandfrontrolleriscalledthemaindraftzone.Theendoftheexittubedeliversthedraftedslivertoasmallfunnelshapeddevicecalledthetrumpetwhichcondensesthesliver,creatingmorefibertofibercohesionandhigherstrength.Atthispointthereisnotwistinthesliver.Sliverisdeliveredintoacylindricalcan.Whenthecaniscompletelyfull,itwillbeautomaticallydoffedorremovedfromthemachineandbereplacedbyanewemptycan.

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Slide51

IntimateBlendandDrawBlend

Thebasictypesofblendedsliversareevidentinthisphotograph.Noticethebarberpoleeffectofthesingleprocessdrawingsliver.Thetwoandthreeprocessdrawingsliversarebetterblendedbutstillshowtracesofbothredandwhitefibers.Thistypeofblendingwouldberecommendedfornoncriticalapplicationswheredyeinginvolvesdarkershades.Thisdegreeofblendingwouldalsobefavorableforheathertypesofyarn.Themostuniformappearanceseenintheintimateblendisrecommendedforlightpastelshadeswherematchingshadeismorecritical.

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Slide52

FiberMovementOverviewAnimation

Thisanimationshowshowthestaplefibersaresubjectedtoashearingaction,slidingbyoneanotherastheymovefromonedraftingzoneintothenextzone.Thisshearingactiontendstostraightenthefibersandremovehooksatthefiberends.Thefibersarenotelongatedastheypassthroughthedraftingrollersunlessafiberissolongthatitisheldsimultaneouslybetweentwosetsofdraftingrollers.

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Slide53

Doubling

Feedingmultipleendsofsliverintoadrawingmachineisreferredtoasdoubling.Doublingprovidestheopportunitytoreduceweightvariationinindividualsliverswhich,inturn,reducestheoverall%CVorcoefficientofvariationorweightvariationinthesinglesliverdeliveredfromtheprocess.Thisgraphicshowsoneheavysliverof90grainsperyarddoubledwithfive60grainsperyardsliversthatareontargetforweight.Theprincipleofdoublingreducesthe50%variationintheheavyslivertoadeliveredsliverofonly8.3%variation.Thedoublingeffectassumesthickplaceswilloffsetthinplacesinthesliverwhilethinplacesinsomewilloffsetthickplacesinotherslivers.

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Slide54

CalculatingDraft

Totaldraftisdeterminedbymultiplyingtheindividualdraftsinthenumberofdraftzones.Forthisexamplethisincludesthebreakdraft,(betweenthebackrollandmiddleroll)multipliedbythemaindraft(betweenthemiddlerollandfrontroll).Anotherwaytocalculatedraftistodividethesurfacespeedofthefrontrollbythesurfacespeedofthebackroll.SurfacespeediscalculatedasRPMoftherollsmultipledbyrolldiametermultipliedbypi.Bothofthesemethodsofcalculatingdraftaresometimesreferredtoasmachineormechanicaldraft.Whentheweightperunitlengthofthesliversfedisdividedbytheweightperunitlengthofthesliverdelivered,thisiscalledthematerialoractualdraft.

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Slide55

CalculatingMaterialDraftExample:Eightsliversweighing72grainsperyardarefedintoadrawingmachine.Thedeliveredsliverweighs68grainsperyard.Whatisthematerialdraft?Solution:MaterialDraft=WeightFed/WeightDel.MaterialDraft=(8x72)/68MaterialDraft=8.47

Inthisexample,eightsliverseachweighing72grainsperyardarefedintoadrawingmachine.Thedeliveredsliverweighs68grainsperyard.Thereforetheinputweightis8times72,which,whendividedbythedeliveredsliverweightof68grainsperyardyieldsamaterialdraftof8.47,ortheinputsliverweightisreducedbyafactorof8.47.

SpunYarns


Slide56

CalculatingMachineDraftExample:Thedeliveryroll(frontroll)ofadrawframe hasasurfacespeedof2,000metersperminuteandthebackroll(feedroll)hasasurfacespeedof277.8metersperminute.Whatisthemachinedraft?

Solution:MachineDraft=SurfaceSpeedofDeliveryRoll/SurfaceSpeedofBackRollMachineDraft=2,000/277.8MachineDraft=7.2

Thisisanexampleforcalculatingmachinedraft.Whendividingthedeliveryrollspeedof2,000metersperminutebythefeedrollspeedof277.8metersperminute,themachinedraftis7.2.

SpunYarns


Slide57

LapWinder

Thereisasizablemarketforcombedcottonyarns.Theseyarnstendtobefinerandarepopularinpremiumproducts.Whenmanufacturingacombedcottonyarnproduct,lapwindingfollowsadrawingprocess,referredtoaspredrawing.Lapwindingissimplythebringingtogetherofamultiplenumberofcottonsliverstobewoundontoalargespoolwhichiscalledacomberlap.Thisphotographshows12sliverscomingfromtherightsideofthelapwinderbeingjoinedwith12othersliversbeingfedfromtheleftsideofthelapwinder.All24willinturnbewoundontoalargespoolwhichiscalledacomberlap.Comberlapsarethentransportedtothecombingmachineandarethematerialsupplyforthecomber.

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Slide58

LapWinderVideo

Thevideoofthislapwindershowstwosetsofslivercansinitscreel.Eachsetcontains12cansofsliver.Thesliversareliftedfromthecansasinthedrawingprocess.Thetwosetsof12sliverswillbejoinedtogetheranddirectedontoalargespoolthatcanbeseenbeingformedbehindthePlexiglaswindow.Acomberlapwhichisalmostfilledandreadytobedoffedcanalsobeseen.Afterdoffing,thelapwillbeplacedontopofthecombingmachineandslowlyunwoundasthefibersgothroughthecombingaction.

SpunYarns


Slide59

ComberOverviewVideo

Thisvideoisofan8positioncombingmachinewithacomberlapateachposition.Eachpositionproducesacombedsliverbutnotthefinishedproduct.Lookingatthissinglepositiononthecomberrevealsthatthecombedfibersareveryparallelandclean.Aftercombing,thefibersgothroughatrumpetwhichcondensesthemintoasliver.The8combedsliversjoinoneanotherandformabandorribbonoffiberswhichgothroughasetofdraftingrollers.Exitingthedraftingrollerswillbeasinglesliverwhichrepresentsthefinishedproductacombedsliver.Thecombedsliveristhencoiledintoaslivercan.Afterdoffingofthecan,thenextprocessistypicallyanotherdrawingoperationwhichhelpsreducethevariationputinthesliverbythecombingaction.

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Slide60

ComberRunningVideo

Ascanbeobservedinthisvideo,acottoncomberisarelativelyslowprocess.Feedrollsonthecomberdeliverashortbeardoffiberstoahalflaprollwhichispartiallycomposedofrowsofsawtoothtypewire.Therowsofwireprogressfrombeingcoarseindensitytobeingfinerindensitymorepointspersquareinch.Asthiscomberisslowed,therowsofwireonthehalflaprollcanbeseenastheycombthroughashortbeardoffiber.Trash,shortfibers,neps,andseedcoatfragmentscollectingonthehalflaprollcanalsobeseen.Thiswastewillbebrushedoffandvacuumedawayasawasteproductcalledcombernoils.Thecombernoilsarereclaimedandspunintootheryarntypes,typicallyopenendcoarsercountyarns.Aftereachbeardoffiberiscombed,itisthenseparatedandanewbeardisintroducedtothehalflaproll.Theshortbeardofcombedfibersispiecedupwithpreviousbeardsoffiberwhichhavebeencombed.Noticetheexcellentparallelizationofthefibersaftercombing.Alsonoticethedegreeoftrashinthefibersbeforeandaftercombing.Inadditiontoremovingshortfibers,parallelingthefibers,andcleaningthem,anothervalueaddedbenefittocombingisblending.Sinceeachoftheeightpositionsfeeds24slivers,thedeliveredsliverwillbeablendof192slivers.Thusoneofthekeybenefitsofcombingisblending.

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Slide61

YarnComparisonTable

Combingisavalueaddedprocess.Combedfibersarenormallyreservedforcombedringspunyarn.Rarelydoesopenendyarnproductionusecombedfibers.However,combingcanbeusedwithvortexyarnproductionwhichwillbediscussedlater.Theadvantageslistedinthistabledohaveanassociatedcost.Combedyarnstypicallycostanywherefrom10to25centsmoreperpoundthancardedyarns.Alsowithcombedyarns,theyarnsizeorcountcanbefiner.Yarnsover40sEnglishcottoncountandfinermustbespunfromcombedfiberswhilecoarsercombedyarnsmaybedesiredtoimprovefabricaestheticsandquality.Combedyarnscontainlongerfiberswhichallowtheyarntohavethesamerelativestrengthwithlesstwistinserted.Thelesstwistallowstheyarntobesofterandhavemoreluster.Lesstwistalsoincreasesproductivityofanyprocess.Thestraighteningofthefibersalsopromoteslusteroftheyarn.

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Slide62

Roving

Followingcombing,thereistypicallyoneadditionaldrawingsteptoimprovethevariabilitycreatedbythecombingandpiecingactions.Thesliverisfedtothenextprocesscalledroving.Theinputmaterialtorovingmaybecarded,onceortwicedrawnsliverorcombedanddrawnsliver.Rovingdraftsthesliverintoapencilsizedstrandoffiberswhichisheldtogetherwithaslightamounttwist.Therovingisthenwoundontoalargerovingbobbinandtransportedtoringspinning.Inotherspinningsystemssuchasopenend,airjet,andvortex,rovingisnotnecessary.

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Slide63

RovingFrameSchematic

Inthediagramshownasinglesliverisfedintoeachpositionontherovingframe.Draftingrollersdraftthesliversintoasetweightperunitlength.Therovingisthentwistedandwoundontoarovingbobbin.Betweenthedraftingrollers,thereisabreakdraftandamaindraftasobservedinthedrawingprocess.Anapron,orminiatureconveyorbelt,controlsfiberflowinthemaindraftzone,sincetherearefewerfiberspercrosssectioninastrandofroving.

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Slide64

DraftingRollersVideo

Thisvideoofarovingmachinehighlightsthedraftingactionatroving.Athreerolldraftingsystemtakesinputsliveranddraftsitintoastrandofroving.Thesliverinputspeedisslowerthantherovingoutputspeed.Adraftintherangeof6to10iscommoninroving.Theslighttwistintherovingrunsuptothefrontdraftingrollerandformsavshapedtriangle.Thedraftingsystemhasrubbertoprollersandsteelbottomrollersaswasseenonthedrawframes.

SpunYarns


Slide65

RovingBobbinsVideo

Rovingiswoundontoabobbinasseeninthisvideo.TherovingisthreadedthroughaninvertedUshapedtubulardevicecalledaflyer.Astheflyerrotates,twistisinsertedintotherovingandassistsinwindingtherovingontothebobbin.Sinceonemoredraftingstepoccursatringspinning,thetwistmustbekeptatalowlevel.Inaddition,theinsertionoftwistalwayslowersproductivity.Noticehowthebobbinmovesupanddowntoformtherovingpackagewhichisfedtothenextprocess,ringspinning.Therovingbobbinseenatthistimeshowsthepackageintegrityincludingcoilsorwrapsperinch,theslighttwistinthepackageandsomesmalltrashthatwillberemovedbythespinningoperation.

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Slide66

RingSpinning

Inringspinningtherovingbobbinishungmanuallyorautomaticallyabovetheringspinningdraftingsystem.Therovingispulledintothedraftingrollerstobedraftedorreducedtoaspecificlineardensityorcount.Thedraftedyarnisthenthreadedthroughapigtailguide,thenthroughacshapeddevicecalledatravelerandfinallyontotherotatingbobbin.Thetravelerrotatesonaflangedmetalringwhichislocatedonaringrail.Theringrailmovesupanddowninshortincrementsasthebobbinisbeingformed.

SpunYarns


Slide67

RingSpinningOverviewVideo

Theringspinningsystemtransformsstrandsofrovingintobobbinsofyarn.Theyarnhasitsfinalcountorlineardensityanditsfinalleveloftwistdeterminedattheringspinningframe.Thepathoftherovingisdownwardandentersthebreakdraftzonewherefibersaresubjectedtoalowdraft.Asthefibersenterthemaindraftzone,ahigherdraftwilltakeplace.Adraftingapronassistsincontrollingthefibersastheyapproachthefrontdraftingroller.Thishelpscontrolthemovementofshortfiberswhichcausethickandthinplacescalleddraftingwaves.Theyarnexitsthefrontrollerwhereavacuumtubeislocated.Thetubeusessuctiontoremovethefibersthatflowfromthefrontrollwhenayarnhasbrokenonitswaytotheringbobbin,thisisreferredtoasanenddown.Aftergoingthroughapigtailguide,theyarngoesthroughaballooncontrolring,throughthetravelerlocatedonthering,andfinallyontotheringspinningbobbin.

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Slide68

TravelerShapesandSizes

Travelersareakeypartofringspinning.Therearedifferenttravelersbaseduponthefibertypebeingrunandtheyarncountspun.Travelersmustbechangedastherawmaterialischangedandastheyarncountbeingproducedchanges.Normaltravelerwearlifeisapproximately10daysto20days.

SpunYarns


Slide69

TravelerWindOnVideo

Thisisanexcellentvideoofhowtheyarniswoundontotheringbobbinwiththeaidoftherotatingtraveler.Thisrotationcreatesaballooningoftheyarnwhichiscontrolledbythemetalballooncontrolring.TheclockwiserotationofthetravelerindicatesZtwistisbeinginserted.Theringrailmovesupanddowninshortincrementsasthebobbinisbeingformed.Thismakesunwindingofthebobbinatthewindingoperationeasierandmoreefficient.

SpunYarns


Slide70

RingSpunYarn

Ringyarnhasconsistentfiberorientation.Allthefiberslooktobeorientedtothesameangle.Thus,basicallyallofthefibershelpcontributetotheyarnstrengthalongwithsomesurfacefiberswhichcontributetoyarnhairiness.

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Slide71

CompactSpinning

Amodificationoftraditionalringspinningiscalledcompactspinning.Inconventionalringspinning,thetwistflowsfromthebobbinupwardtothefrontrollofthedraftingsystem.Atthispointavshapedortriangularprofileexistscausingsomefiberendstomigratetotheyarnsurfacecreatingamorehairylikeyarn.Incompactspinning,thetriangledisappearsandtheyarnismorecompactandlesshairy.Thisismadepossiblebyplacinganextrasetofrollersinfrontofthefrontrollerontheringspinningframe.Theextrabottomrollerisperforatedwherethereissuction.Thepressurefromtheextratoprollerandthevacuumsuctioncreatesthecompactionoftheyarnsurface.Thepurportedlowerhairiness,betteruniformity,higherluster,andhigherstrengthofthecompactyarnaidsdownstreamprocessing.

SpunYarns


Slide72

CompactSpinningVideo

Seeninthisvideoisanextraattachmenttothefrontofthedraftingsystemonaringspinningmachine.Asdiscussedinthepreviousslide,theattachmentincludesanadditionaltoprollerandaperforatedbottomrollerwithvacuumsuction.Analternativetotheperforatedrollerisastationarytubewithanarrowslitforvacuumsuction.Aswiththeperforatedroller,thevacuumsuctionfromthenarrowslitinthestationarytubeaidsinbringingthefiberstogetheratthedeliveryofthefrontroll.Thisresultsinastraightlineconfigurationratherthaninatriangularconfigurationasinconventionalringspinning.Thekeytoimprovingtheyarnqualitypropertiesistheeliminationofthetwisttriangleprevalentinconventionalringspinning.

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Slide73

WinderOverview

Afterthesmallringspunbobbinsofyarnaredoffed,theyaremanuallyorautomaticallytransportedtothewindingoperationwheremanyringbobbinsarecombinedontoalargeryarnpackagetobeusedinknittingorweaving.Atwinding,aqualitycontrolcheckcanbeintroducedthroughtheuseofyarnclearerdeviceswhichdetectyarnfaultsandremovethemautomatically.Thewinderthenpiecesthebrokenyarnsusingairormechanicalmeans.Inthisphotographtheyarnbobbinsarelocatedatthebottomofthewindingunitsandthewoundyarnpackageslocatedatthetopofthemachine.

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Slide74

WinderAirSpicer

Airsplicersarecommononbobbinwinders.Anotheroptionistoincorporateanautomaticknotter.Splicingqualityisofutmostimportanceandmustbecheckedonaregularbasis.Splicesaretypically85%ofthenormalyarnstrength.

SpunYarns


Slide75

OpenEndYarn

Openendspinningisanalternativetoringspinningandhassomelimitationsandadvantageswhencomparedtoringspinning.Noticethatcansofsliverarefedtotheopenendframeandnotrovingbobbins.Noseparatewindingisneededsincewindingoccursaspartoftheopenendmachine.Thetancoloreddeviceisapiecerwhichmovesaroundthemachine,lookingforyarnendbreaks.Whenabreakoccurs,theautomaticpiecercomestotheappropriatepositionandmakesthenecessaryrepair.Openendmachinestypicallyhavedevicesthatalsoautomaticallydoffthefullyarnpackages.Throughoutmanypartsoftheworldthesemachinesarefullyautomatedtoamuchhigherdegreethanringspinningmachines.

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Slide76

OpenEndSpinningVideo

Thismodernopenendspinningmachineisrunningatafullproductionspeed.Ateachposition,aninputsliverispulledintothespinboxbytheactionofthefeedroll.Thesliverisfedmuchslowerthantheyarnisdeliveredduetothedraftofthefiberstakingplace.Insidethespinbox,thefiberscollectintherevolvingrotorandaretwistedintoayarn.Atthispointtheyarnexitsthespinboxandgoesthroughayarnclearerwhichdetectsanyundesirableimperfectionsintheyarn.Wheneveranendbreaks,thepiecingunitstopsattheappropriatepositionandreconnectstheyarnbyfeedingthebrokenendbackintotherotorwherepiecingoccurs.Theyarnoscillatesbackandforthasitpassesunderadeliveryrollertopreventexcessivewearorgroovingofthedeliveryrollersurface.Atthispoint,theyarnhastheoptionofpassingoverawaxingunitwhichisnormallyappliedtoknittingyarns.Thebowshapedarmabovethewaxingdiskprovidesconsistentyarntensionastheyarniswoundfromthesidesofthepackagetothemiddleofthepackage.Awindingdrumunderthepackageassistsinpackagerotationandareciprocatingguideevenlydistributestheyarnoverthelengthofthepackage.Thelastsectionofthevideoshowsthepiecerstoppingtohelprepairabrokenyarn.Therotorisautomaticallyopenedandcleaned.Theyarnfromthepackageisfedbackintotherotorwheretheyarnispieced.

SpunYarns


Slide77

OpenEndSchematic

Ateachpositionofopenendspinning,thesliverentersafeedrollandisfedslowlytoasawtoothedcomberroll.Therollcombsoutindividualfibersthatinturntravelthroughataperedchanneluptotherotor.Onceintherotorthefiberscollectintherotorgrooveandaretwistedtogetherastherotorspinsataveryhighspeed.Thetwistedyarnthenexitstherotorthroughadofftubeandiswoundontoalargepackage.Thenavelcreatessomefalsetwistwhichfeedsbackintotherotorandhelpstodecreaseendbreaks.Therearedifferenttypesofnavels,eachtypehavingadifferentsurfacethattheyarncomesincontactwith.Navelswitharoughsurfacecreatedbygroovesorotherspecialcutoutshapestendtoroughuptheyarn,makingitmorehairy,softer,andbulkier.Smoothersurfacednavelsmaketheyarntighter,stronger,lesshairy,lessbulky,andnotassoft.Thetermopenendcomesfromthefactthattheyarncomestoanendinsidetherotorascanbeseeninthisdiagram.

SpunYarns


Slide78

OpenEndAnimation

Thisanimationshowstheinputslivergoingunderthefeedrollwhichdeterminestherateoffiberflowandultimateyarncountdelivered.Thefibersareseparatedfromthesliverbythewireteethonthecomberroll,andduringthisseparation,anysmalltrashparticlesstillremaininginthesliverareremoved.Thefibersleavethecomberrollandaredepositedintotherotorwheretheyarnisformed.

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Slide79

OpenEndSpinningAnimation

Thisanimatedviewofyarnformingintherotorrevealsthecontinuousflowoffibersintotherotorandyarncontinuallydeliveredfromtherotor.Theeverpresentopenendofyarninsidetherotorisclearlyseenasasmalltail.Theyarnisactuallypulledfromtherotorgroovebyadeliveryrollsystem.Thedeliveryrollspeeddeterminestheamountoftwistinsertedintotheyarn.Therotorspeedremainsconstant.

SpunYarns


Slide80

OpenEndSpunYarn

Unlikethefiberorientationseeninringspunyarns,thefiberorientationinanopenendyarnisveryrandomandinconsistent.Duringeveryrotationofaspinningrotor,thepointwheretheyarnisbeingpeeledawayfromtherotorgroovealignswiththepointwherefibersarefeedingintotherotorfromthetransportchannel.Atthispointafibermaybewrappedprematurelyaroundtheyarnandendupperpendiculartotheyarnaxis.Thesesocalledwrapperfibersdonotcontributesignificantlytotheyarnstrengthbutdocontributetotheyarnhavingaharsherhandorfeel.Thuswrapperfibersareinherenttotheopenendspinningprocess.Thesmallertherotordiameter,thehigherthefrequencyoftheoccurrenceofwrapperfibers.

SpunYarns


Slide81

AirJetSpinning

Athirdtechnologyusedtoproduceshortstapleyarnsisairjetspinning.Airjetyarnscurrentlyrepresentasmallpercentageofthespunyarnmarket.Fibersarefedintoairnozzleswherehighvelocityrotatingairwrapsaribbonoffibersaroundacoreofmostlyparallelfibers.Thedegreeoftightnessoftheribbonfibers,andthefibertofibercohesionoftheofthecorefibersinfluenceyarnstrength.Tighterwrappingofribbonfibersproducesastifferyarnwithaharsherhandorfeel.However,anadvantageisthatthistypeofspunyarncreatesalowertendencyfortheyarntogeneratepillinginfabrics.Conventionalairjetspinningismosteffectivewhenprocessing100%manmadefibers.Blendsofmanmadefibersandcottonfibersarepossibleonlywhenthemanmadefibercomponentisahighpercentageoftheblend.Thevariablestaplelengthofcottonfibersandthepresenceofshortfiberscause100%cottonyarnstobetooweakformostapplications.

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Slide82

AirJetSpinningAnimation

Thisanimatedversionofconventionalairjetspinningillustrateshowthesliverentersintoarollerdraftingsystemmuchlikeseeninthemanufactureofringspunyarn.Attheexitsideofthefrontdraftingroller,anarrowbandorribbonoffibersisseparatedfromthemaincoreofthefibers.Thisribbonoffibersistwistedaroundthecorefibers,bytheactionofthefirstairnozzle.Theairinthefirstnozzlerotatesclockwise.Asecondairnozzle,withairrotatingcounterclockwise,createsfalsetwistintheyarnstrand.Theresultisthatthetwistbeforethesecondairnozzleisintheoppositedirectionfromthetwistafterthesecondairnozzle.Therefore,theoutgoingtwist(ortheresultingtwistafterthesecondairnozzle)tightenstheribbonofwrapperfibersandprovidestheyarnwithitsrequiredstrength.Controllingtheairpressureoftheairnozzlesandthethroughputspeedofthefiberdeterminesthelevelofyarnstrength.Theyarnformedconsistsofacoreofstaplefiberswithlittleornotwistandsurfacefiberswrappedaroundthecorebundle.Specialcareisrequiredinsubsequentprocessingsoasnottodamageorabradethewrappingfibers,whichwouldleadtoyarnweaknessandeventualbreakage.

SpunYarns


Slide83

AirJetSpinningVideo

Thisvideoshowsadrawingsliverenteringthedraftingrollersofanairjetspinningmachine.Thedraftingrollersdeterminetheyarnsize,orcount.Oncethefibersexitthefrontrollofthedraftingsystem,theyentertheairnozzleassembliespreviouslydescribed.Aftertheyarnisspun,itentersayarnclearingdevice,passesoverawaxingunitandtheniswoundontoalargeyarnpackage.Themachinghasarobotforautomaticpiecingofyarnbreaksandautomaticdoffingoffullyarnpackages.

SpunYarns


Slide84

VortexSpinning

Vortexyarnisformedasfibersenterasmalltornadolikevortexofair.Thefibersflarebeforeenteringatubularstructurewheretheflaredfiberstwistaroundtheyarnbundle.Asseeninthisphotograph,theresultingyarnshowsnoevidenceofwrapperfibersorofanyribbonofwrapperfibers.Infact,thisyarnstructureissimilartothatofringspunyarn.However,theproductionrateis2022timestheproductionrateforringspinning.Vortexspinningcanproduce100%cottonyarnswithadequatestrengthaswellasmanmadestaplefiberyarns.Vortexspinningisanevolvingtechnologyfoundinonlyafewspunyarnmanufacturingplants.

SpunYarns


Slide85

VortexSpinningAnimation

Similartoconventionalairjetspinning,vortexspinningsuppliessliverastheinputmaterialandusesrollerdraftingtoreducethefibermasstothedesiredyarnsize.Thevortexedyarnpassesthroughayarnclearer,awaxingdevicewhenneeded,andiswoundontoayarnpackagewhichisautomaticallydoffedwhenfull.Vortexspinningutilizesfourairnozzlesincloseproximitytooneanotherwhichcreatesaveryhighvelocityofrotatingairtotwistfibersintoayarn.Asseenintheanimation,fibersflareoutwhentheyareintroducedtothevortexofair.Astheyarnflowsforward,theseflaredfibersarebroughttogetherandaretwistedtoformtheyarnbundle.Apercentageofshortfiberswillbevacuumedawayattheflaringpoint,creatingfiberwastethatisnotafactorinringspinning,openendspinning,andconventionalairjetspinning.Theamountofwastefiberscanbereducedbycombingthefiberspriortospinning,whichmanycompanieschoosetodo,althoughthisaddsanadditionalcosttothefinalproduct.Theorientationofthefiberscloselyresemblestheorientationoffibersinaringspunyarn.Therearenowrapperfibersnoranyribbonofwrappingfibersinvortexyarns.

SpunYarns


Slide86

SpunYarnCharacteristics

Thischarthighlightstheadvantagesanddisadvantagesofeachtypeofyarnthathasbeenpreviouslydescribed.Thetoppartofthechartrepresentsthepositivecharacteristicsforeachtypeofyarnandthebottomsectionofthechartshowsthemorenegativecharacteristics.Basedonthedatainthechart,answerthefollowingquestions:1.Whichtypeyarnhasthefinestcounts?2.Whichtypesofyarntendtohavemoretorque?3.Whichtypeofyarnhaslesstendencytopill?4.Whichtypeofyarnisthesoftest?5.Whichtypeofyarntendstobemoreabrasive?6.Whichisthemostunevenyarn?7.Whichyarnwouldtendtohavelowerelongation?8.Whichyarndyesdarker?9.Whichyarnisproducedthefastest?10.WhichyarncanbetwistedineithertheSorZdirections?

SpunYarns


Slide87

SpunYarns

Thesemicroscopicviewsofthedifferenttypesofspunyarnspreviouslydiscussedrevealhowdifferenttheyarnsareinstructure.Thereisnoproblemidentifyingthewrapperfibersintheopenendyarn.Itiseasytoidentifytheribbonofwrappingfibersintheairjetyarn.Theringspunyarnandthevortexspunyarnhavesimilarfiberorientation.Usingamicroscopeisthesimplestandmostaccuratewaytoidentifythedifferentyarntypes.

SpunYarns


Slide88

ZTwistYarn

MostCommontwistdirectionReferredtoasrighthandtwistTwistmechanismrotatesclockwiseCanbeusedwithOEandringspunyarns

Forspunyarns,yarntwistisanimportantvariableaffectingbothyarnpropertiesandfabricproperties.Therearetwodirectionsinwhichayarncanbetwisted.Whenayarnistwistedinaclockwisedirection,thefibersformahelicalangleattheyarnsurface.ThisangleconformstothemiddlepartoftheletterZand,therefore,isreferredtoasZtwist.Thisisthemostcommontwistdirectionandsometimesreferredtoasrighthandtwist.OpenendandringspunyarncanbeproducedwithZtwist.

SpunYarns


Slide89

STwistYarn

MaybecalledlefthandorreversetwistTwistmechanismrotatescounterclockwiseCannotexistinopenendyarn

Whentheassociatedtwistmechanismrotatesinacounterclockwisedirection,theresultanthelicalangleconformstothemiddlepartoftheletterSandtheyarnissaidtohaveStwist.Thisisalsoreferredtoaslefthandorreversetwist.Stwistdoesnotexistinopenendyarn,butcanbethetwistofchoiceinaringspunyarn.Airjetandvortexyarnsdonothaveaconventionaltwiststructure;however,theirsurfacefiberscantakeonwhatappearstobeaSorZconfiguration.

SpunYarns


Slide90

InfluenceofTwistDirection Visibilityofdiagonallinesintwillweaves:

Ztwistedyarnsmakethetwilllinemoreraisedinlefthandtwills.

Stwistedyarnsmakethetwilllinemoreraisedinrighthandtwills.

Forreducedfabrictorqueincircularknits: Clockwisemachinerotation useStwist Counterclockwisemachinerotation useZtwist

Forlowertorqueinpliedyarns plytwistisintheoppositedirectionfromthesinglesyarntwist

Twistdirectioninfluencestheprominenceofthetwilllineinfabricconstructedwithatwillweave.Forexample,Ztwistedyarncausesthetwilllineinalefthandtwillfabrictobemoreprominentwhilethesameyarnputinarighthandtwillfabricwillcreateaflattertwillline.Whenthetwistdirectionintheyarnisoppositeofthetwilldirectioninthefabric,thefabrictwilllinewillbemorevisible.Thisscenarioalsotendstoproduceasofterfabricaswell.Circularknittingmachinescanalsohavedifferentdirectionsofrotationandtheyarntwistdirectioncaninfluencefabrictorque.Mostpliedyarnsareplytwistedintheoppositedirectiontothedirectionofeachsinglesyarnwhichreducesyarntorqueandanyresultingfabrictorqueissues.

SpunYarns


Slide91

TwistEffectsonYarnPropertiesDegreeofYarnTwistAffectstheYarn's:1.Diameter2.Contraction3.Softnessorhardness(hand)4.Torqueorliveliness5.Bendingbehavior6.Absorbency7.Coveringpower8.Permeability9.Tensilestrength10.Elasticperformance/extensionandrecovery11.Resistancetocreasesandabrasion12.Pillingbehavior13.Luster

Whatmightoccurifayarnsupplierpurchasedalowergradeofcottonwhichcontainedmanyshortfibers?Inspinning,theyarnwouldexperienceanincreaseinendbreaksresultinginlowerspinningefficiency.Tonegatethisproblem,thespinnermightincreasetheyarntwisttoreduceendbreaksandraisethespinningefficiency.Usingthelistinthistable,howwilleachofthesefactorsbeaffectedbyanincreaseinyarntwist?Respondwithsuchwordsasmoreorless,higherorlowerwhenappropriate.Thecorrectresponsesareonthenextslide.

SpunYarns


Slide92

TwistEffectsonYarnPropertiesDegreeofYarnTwistAffectstheYarn's:1.Less Diameter2.More Contraction3.HarderHandSoftnessorhardness(hand)4.More Torqueorliveliness5.Stiffer Bendingbehavior6.Less Absorbency7.Less Coveringpower8.Less Permeability9.More(toapoint)Tensilestrength10.More(toapoint)Elasticperformance/extensionandrecovery11.More Resistancetocreasesandabrasion12.Less Pillingbehavior13.Less Luster

Thereisnonarrationforthispage.

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Slide93

TwistEffectsonFabricPropertiesDegreeofYarnTwistAffectstheFabric's:1.Texture2.Hand3.PerformanceExpectations4.Serviceability5.Appearance6.Durability

Manyoftheeffectsofaddingtwisttoayarninfluencefabricpropertiesaswell.Thepropertieslistedinthisslidewillalsobeinfluencedbytheleveloftwistintheyarns.Fabricsmadefromyarnshavingahighleveloftwisttendtofeelharshertothehand,butdemonstratebetterwear,durability,andpillingperformance.

SpunYarns


Slide94

NotationsforDegreeofYarnTwist

1.TurnsPerInch(TPI)2.TwistMultiple(TM)CommonCalculationPerYarnNumber:TPI=TMxSquareRootofYarnNumberCommonTwistMultiples: KnitYarns2.2 3.9 FillingYarnsforWeaving 3.7 4.1 WarpYarnsforWeaving 4.1 4.6 VoileandWovenCrepe 4.8 5.5

Theamountoftwistinaspunyarnisdescribedasturnsoftwistperinchofyarnorturnsoftwistpermeterofyarn.Thehelicalangleoftwist,aspreviouslydescribed,changesasmoreyarntwistisadded.Thisangleisrelatedtowhatiscommonlycalledthetwistmultiple.Twistmultipleisafunctionofthetangentofthehelicalangleformed.Asmoretwistisadded,thetwistmultipleorTMisincreased.Twistmultiplevaluesforyarnsvaryaccordingtotheirenduse.Sincewarpyarnsareundermuchtensionduringweaving,theseyarnsneedahigherTMforaddedstrength.Converselyknittingyarnsarenotunderasmuchtensionduringtheknittingprocessand,therefore,donotneedasmuchtwistandwillhavelowertwistmultiple.Problem:Usingthecalculationseenonthisslide,determinehowmuchtwistisinsertedina16/1knittingyarnwithaTMof3.5.Answer:TPI=3.5xSquareRootof16=3.5x4=14twistsperinch

SpunYarns


Slide95

SpunYarnModifications

PliedYarns Slub andMulticountYarns ElasticCoreYarns

Therearewaystomodifyyarnstoenhancefabricappearanceand/orperformance.Thefollowingslideshighlightsomeofthemorecommonyarnmodifications.

SpunYarns


Slide96

SingleandPliedYarnTwist

Mostpliedyarnshavetheplytwistdirectionoppositetothatusedinthecomponentyarnsforlessyarntorque

Singlesyarnscanbetwistedtoformpliedyarnsandpliedyarnscanbetwistedtoformcordsorcabledyarns.Whenworkingwithapliedyarnsuchas2ply,3plyoranynumberofplies,thepliedyarnisconsideredtobeoneyarnirrespectiveofthenumberofplies.

SpunYarns


Slide97

PliedYarnsYarnisPliedto: Introducedifferentfiberyarns. Combinespunandfilamentyarns. Addtoorincreasethestrengthofsinglestrandyarns. Utilizemultistrandsoffineyarnstoproduceathickstrand. Reducetorqueintheyarn Produceasmootheryarn. Produceayarnwithuniformdiameter. Introducetexturedornoveltyyarns. Addcolorinterest.

Therearevariousreasonstoplyyarns.Onepurposemightbetocombinedifferentyarntypes,suchasspunandfilament,inordertomeetspecificperformancecriteria.Manynoveltyorfancyyarnsareproducedusingtheplyingtechnique.Interestingcolorcanbedevelopedbyplyingdifferentcolorsofyarn.Ingeneral,pliedyarnsaremoreexpensivethansingleyarnsduetotheadditionalprocessofplying.

SpunYarns


Slide98

PliedYarnExample

TheStwistdirectionintheplytwistingofthis2plyyarncanbeseeneasilyinthisenlargedphotograph.TheindividualyarnswereZtwisted.

SpunYarns


Slide99

CabledYarnExample

Acabledyarnsampleisshownatthistimetoemphasizethecoarsenessandbulkinessofcableyarns.

SpunYarns


Slide100

TwoforOneTwister

Oneofthemostcommonmethodsforplyingyarnsiswithatwoforonetwister.Twopackagesofyarnareplacedontopofoneanotherandthetwoyarnsarepliedtogether.Twoturnsoftwistareinsertedintotheyarnsforeachrevolutionofthetwistingdevicewhichincreasesthespeedoftheplyingprocess.Manytimestwoyarnsarelaidinparallelontoapackageonwhatiscalledanassemblywinder.Thepackagesarethenplytwistedonthetwoforonetwister.

SpunYarns


Slide101

CoreSpinningVideo

Thisvideoshowshowcorespunyarnisproducedonaringspinningmachine.Aspandexfilamentyarnisfedfromtheyarnpackage,throughaspecialguide,andthenplacedbehindthefrontrolleronthespinningmachine.Staplefibers,suppliedbytheincomingrovingstrand,arespunaroundthespandexcore.

SpunYarns


Slide102

BoucleYarnExample

Thispopularnoveltyyarniscalledaboucle.Acoreyarnformsthebaseofthestructureandasecondyarnisoverfedontothecoreyarnformingloopsoftheeffectyarnonthesurfaceoftheyarn.Athird,veryfine,bindingyarnissuppliedinordertofirmlyattachtheeffectyarntothecoreyarn.

SpunYarns


Slide103

Amsler FabricExample

Amslerisoneoftheleadingsuppliersofequipmentusedinthemanufactureofengineeredyarnscontainingvariousdimensionsofslubsandyarnsofmultiplecount.ThisisanexampleofAmsleryarnbeingusedinaknitfabric.Variationsinyarnthicknesscanbeengineeredinaveryrandompattern.Slubsintheyarncanbeformedinvariablelengthsasevidencedinthisactualfabricsample.Thistechnologycreatesafabrictextureandgivesthefabricdesigneranadditionaltooltoworkwithincreatingdesigneffectsthatmightbedesirableinagivenfabric.

SpunYarns


Slide104

TwistedSlub YarnExample

Specialeffectsinyarnsareoftenproducedbyplyingdissimilarsingleyarns.Inthisphotographanunevenyarnwaspliedwithafiner,morehighlytwistedyarntoproducethespecialeffectshown.

SpunYarns


Slide105

YarnTesting YarnStrength(SingleEnd/Skein) YarnElongation(%) YarnEvenness(%CoefficientofVariation) YarnHairiness YarnCountandCountCV TwistAmountandDirection YarnFriction(KnitYarnsMostly) ImperfectionCount

Therearethevariousimportantphysicalpropertiestobetestedinspunyarns.Testingcanbedoneasaninternalqualitycontrolprogramintheyarnmanufacturingplantorbythecustomertoverifyincomingyarnquality.Specificationsareusuallyagreeduponbythesupplierandcustomer.Whenspecificationsarenotmet,thecustomerhasreasontorejectayarnshipmentortoreceiveadiscount.

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