針織學(xué)全套課件

KnittingTechnology

Chapter1TheDefinitionofknitting1.1TheFabricFormingMethodThereare3kindsoffabricformingmethod,theweaving,theknittingandthenon-woven.*

TheweavingByinterlacingtwosetsofyarnsatrightanglesintofabricAconventionalwovenfabricisatextilestructureformedonaloomwhentwosetsofyarnsareinterlacedatrightangles.Thelongitudinalyarnsareknownasthewarpandthewidthwiseastheweft.*TheKnittingByintermeshingtheloopsofyarnintofabricNormally,theknittedstructureconsistsofonesetofyarn,weftorwarp,andisdividedintoweftknittedfabricandwarpknittedfabric.*TheNon-wovenBybondingfibers,filaments,yarnsorcombinationsoftheseintofabric*1.2knittingclassificationknittingmaybedividedintotwotypesaccordingtotheformationmethodWarpknittingandweftknittingWarpknittingweftknitting*1.2.1

WeftknittingTheyarnisfeedintotheneedlealongtheweftdirectionandknittedintofabric.

*1.2.2

WarpknittingTheyarnisfeedintotheneedlealongthewarpdirectionandknittedintofabric.

*

1.3KnittedstructureKnittedstructureareprogressivelybuiltupbyconvertingnewlyfedyarnintonewloopsintheneedlehooks,theneedlesthendrawthesenewloopthroughtheoldloop.

*1.3.1Knittedloopstructure(1)

Loop:Thesimplestunitofknittedstructure.Itconsistsofneedleloopandsinkerloop.Theneedleloopincludeaheadandtwosidelimbs.

*(2)

KnittedStitch

Thebasicunitofintermeshingandusuallyconsistsofthreeormoreintermeshedloops,thecenterloophavingbeendrawnthroughtheheadofthelowerloopthathadinturnbeenintermeshedthroughitsheadbytheloopwhichappearsaboveit.*(3)

FaceloopstitchThesideofthestitchshowsthenewloopcomingthroughtowardstheviewerasitpassesoverandcoverstheheadoftheoldloop.Facelooptendtoshowthesidelimbsoftheloopsasaseriesofintermeshing‘V’s.*(4)

ReverseloopstitchThisistheoppositesideofthestitchtothefaceloopsideandshowsthesinkerloopsinweftknittingandtheunderlapsinwarpknitting.*(5)

CourseAcourseisapredominantlyhorizontalrowofloopsproducedbyadjacentneedlesduringthesameknittingcycle.Inweftknittedfabricsacourseiscomposedofyarnfromasinglesupply.

*(6)

WaleAwaleisapredominantlyverticalcolumnofneedleloopsproducedbythesameneedleknittingatsuccessiveknittingcyclesandthusintermeshingeachnewloopthroughthepreviousloop.Inwarpknittingawalecanbeproducedfromthesameyarn.*(7)

Stitchdensity(a)

WaledensityThewalesinacentimeteror5centimetersorinaninchalongthecourse.(b)

CoursedensityThecourseinacentimeteror5centimetersorinaninchalongthecourse.

*(8)

StitchlengthTheyarnlengththatformaloop.*1.3.2KnittedFabric(1)

SinglefacedfabricSinglefacedfabricisproducedinwarpandweftknittingbytheneedlesoperatingasasingleset.Itshowsthefaceloopsinonesideandthe

reverseloopsinanotherside.(2)

Double-facedfabric:

Double-facedfabricisproducedinwarpandweftknittingwhentwosetsofindependentlycontrolledneedlesareemployed.Itshowsthefaceloopsorthe

reverseloopsinbothside.*(3)

Piece-goodsThefabricinacontinuousuninterruptedlengthofconstantwidth;Thefabrichereneedbemadeupintoapparelthroughcuttingandsewing.*(4)

Garment

thefabricinacertainlengthandwidthwhichfittothebody-sizeandSometimeswithacertainshapeorfullyfashion;TheGarmentherecanbemadeupintoasweaterthroughsewingbutthecuttingisnotnecessaryoronlyalittlecuttingisnecessary.

*(5)

SelvedgedFabricAselvedgedfabricisonehavinga‘self-edge’toitandcanonlybeproducedonmachineswhoseyarnreciprocatebackwardsandforwardsacrosstheneedlebedsothataselvedgeisformedastheyarnrisesuptothenextcourseattheedgeofthefabric.(6)

TubularFabricProducedmainlyindouble–facedformorsingle-facedstructureoncircularmachines.*(7)

CutEdgeFabricByslittingopenatubeoffabricproducedonacircularmachine.Aslittubeoffabricfroma30-inch(76cm)diametermachinewillhaveanopenwidthof94inches(2.38m)atknittingbeforerelaxation.*

1.4KnittingMachineclassification1.4.1WeftKnittingMachine(1)

Circularweftknittingmachine(a)Beardedneedlemachinesinkerwheelknittingmachineloopwheelknittingmachine*(b)Latchneedlemachine:circularsinglejerseymachineribmachine

interlockmachineterrymachine3-threadfleecymachine

jacquardweftknittingmachinehosierymachine

*(2)

Flatknittingmachine(latchneedle)handflatmachinecomputerizedflatmachineglovemachine*(3)

Straightbarframe(beardedneedle)

(Cottonmachine)

*1.4.2WarpKnittingMachine(1)

Raschelwarpknittingmachine*(2)

Tricotwarpknittingmachine

*1.5MachineGauge(1)

The“machinegauge”isdeterminedasthenumberofneedlesinoneinchofneedlebedi.e.2.54cm.(2)

Machinegaugeinfluenceschoiceofyarnandcount,andaffectsfabricpropertiessuchasappearanceandweight.

*1.6Needle1.6.1BeardedneedleTherearesixmainpartsofthebeardedneedle:1-stem2-head3-beard4-eyeorgroove5-shank6-tip

*1.6.2LatchneedleThelatchneedlehasfivemainfeatures:1-stem2-hook3-latch4-rivet5-butt

*1.6.3Compoundneedleitincludetwoseparatelyparts:

1-theneedle2-thetongue(closemember)*1.7TheBasicknittingAction*

1.7.1KnittingActionoftheBeardedNeedle(1)Clearing：Theoldloopisclearedfromthehooktothestembelowthetipofthebeard.(2)Feeding:Anewpieceofyarnisfedontothestemandbringedintohookbythesinkerwheel.(3)

Closing:Thepresserpressesthebeardandthetipofbeardentertheeyecutinstem.Thenewyarnthereforeisenclosedbybeard.*(4)

Landing:Theoldloopmovesupwardsandislocatedontheoutsideofthebeardassoonasthebeardisclosed.(5)

Knocking-overandlooplengthformation:Astheoldloopcontinuesupwardstheoldloopslideofftheneedleandtheyarnisdrawnthroughitforminganewloop.*1.7.2KnittingActionoftheLatchNeedle*sinkertopcircularlatchneedlemachine*(1)ClearingAstheneedlemoveupwardsalongtheclearingcam,theoldloopslideinsidethehookandisclearedfromthehookandlatchspoonontothestem.Atthispointthefeederguideplateactsasaguardtopreventthelatchfromclosingtheemptyhook.*(2)YarnfeedingandlatchclosingTheneedlestartstodescentthestitchcamsothatitslatchisbelowthevergewiththeoldloopmovingunderit.Atthistimethenewyarnisfedthroughaholeinthefeederguidetothedescendingneedlehook.Theoldloopcontactstheundersideofthelatchcausingittocloseontothehook.*(3)

Closingandlanding:Astheneedlecontinuesdownwardsthelatchisforcedtocloseundertheinfluenceoftheoldloop.Theoldloopislocatedontheoutsideoftheclosedlatch.*(4)

Knocking-overandlooplengthformationAstheheadoftheneedledescendsbelowthetopofthetricktheoldloopslidesofftheneedleheaddrawsthelooplength,whichisapproximatelytwicethedistancetheheadoftheneedledescendsbelowthesurfaceofthesinkerortrick-platesupportingthesinkerloop.

*1.8KnittingNotationsAknittingnotationisasimple,easilyunderstoodsymbolicrepresentationofaknittingrepeatsequenceanditsresultantfabricstructurewhicheliminatestheneedfortimeconsumingandpossiblyconfusingsketchesandwrittendescriptions.*1.8.1Sketchesofstitch*1.8.2PatterngridInasquaredpaper,eachsquarerepresentsaneedleorastitchandthedifferentsymbolinasquarerepresentsadifferenttypestitch.Forexample,an‘X’symbolinasquarecanrepresentafaceloop,an‘O’isabackloop.Themeansofasymbolcanbedefinedbyyouselfaccordingtothestitchwhatisknitted.The‘X’canalsoisatucklooporaloopknittedwithacertaincoloryarnetc.*1.8.2Weftknittingthreadpathnotation*1.8.3WarpKnittingLappingDiagram*Chapter2

TheFourPrimaryBaseStructureofWeftKnittedFabric

*Therearefourprimarybasestructures:plain,rib,interlockandpurl,fromwhichallweft-knittedfabricsarederived.Eachiscomposedofadifferentcombinationoffaceandreversemeshedstitchesknittedonaparticulararrangementofneedlebeds.Eachprimarystructuremayexistalone,inamodifiedform,withstitchesotherthannormalclearedloops,orincombinationwithanotherprimarystructureinagarmentlengthsequence.

*2.1PlainFabric(singlejersey)2.1.1TheStructure

Plainisproducedbytheneedlesknittingasasingleset,drawingtheloopsawayfromthetechnicalbackandtowardsthetechnicalfacesideofthefabric.Itisthebasestructureofladies’hosiery,fullyfashionedknitwearandsinglejerseyfabrics.Plainiscomposedentirelyoffaceloops(orentirelyofbackloops).Itsbasicstructureunitisonlyonefaceloop(oronebackloop).

*2.1.2Thecharacteristics(1)

Theappearanceofthefaceandbackdiffer

Thetechnicalfaceissmooth,withthesidelimbsoftheneedleloopshavingtheappearanceofcolumnsofVsInthewales.Thetechnicalbackhasanappearanceofcolumnsofsemi-circlesformedbytheheadsoftheneedleloopsandthebasesofthesinkerloops.

*(2)

Extensibilitywidthwiseisapproximatelytwicethatofthelengthdirection.itnormallyhasapotentialrecoveryof40percentinwidthafterstretching.*(3)

Theedgesofthefabrictendtocurlorroll*(4)

Arun(collapseofawale)willoccurifacutorexposedloopisstressed.Thedirectionofcollapsecanbeeitherfromtoptobottomorviceversa(5)

Thefabriccanbeunraveled,coursebycoursefromthecourseknittedlastorfromthecourseknittedfirst

*(6)

Thefabricthicknessisapproximately2timesthediameteroftheyarnused.(7)Plainisthesimplestandmosteconomicalweftknittedstructuretoproduceandhasthemaximumcoveringpower.

*2.1.3Theknitting(1)

Producingbyloopwheelorsinkerwheelbeardedneedleknittingmachine(2)

Producingbysinkertop(oropentop)circularlatchneedlemachine(3)

Producedbyflatknittingmachine(4)

Producedbystraightbarframe(Cottonmachine)*2.2RibFabric2.2.1TheStructure(1)Ribrequirestwosetsofneedlesoperatinginbetweeneachothersothatwalesoffacestitchesandwalesofreversestitchesareknittedoneachsideofthefabric.Thesimplestribfabricis1×1rib.Itconsistsofalternatefaceandbackwales,whereafacewaleiscomposedentirelyoffaceloopsandabackwaleiscomposedentirelyofbackloops.

*(2)Thereisarangeofribset-outsapartfrom1×1rib,thefistfigureinthedesignationindicatesthenumberofadjacentplainwalesandthesecondfigure,thenumberofadjacentribwales.Singleorsimpleribshavemorethanoneplainwalebutonlyoneribwale,suchas2×1,3×1,etc.Broadribhasanumberofadjacentribaswellasplainwales,suchas6×3DerbyRib.

*2.2.2Thecharacteristicsof1×1rib(1)

Theappearanceofthefaceandbackareidentical(1×1rib,2×2rib)(2)

Theextensibilityofthefabricwidthwiseisapproximatelytwicethatofsinglejersey.Thelengthwiseextensibilityisessentiallythesameasinsinglejersey.(3)

Thefabricdoesnotcurlattheedges.*2.2.2Thecharacteristicsof1×1rib(4)

Arunwilldevelopinthefabricifanexposedloopiscut,asisthecaseforsingleknits,exceptthatthedirectionofcollapsewillbefromtoptobottomonly.(5)

Thefabriccanbeunraveledcoursebycoursebutonlyfromtheendlastknitted.

*2.2.2Thecharacteristicsof1×1rib(6)

Therelaxedfabricistheoreticallytwiceasthickandhalfthewidthofanequivalentsinglejerseyfabric.(7)

Particularlysuitablefortheextremitiesofarticlessuchastopsofsocks,thecuffsofsleeves,ribbordersforgarments,andstrappingforcardigans.*2.2.3Knitting(1)Producingbybody-sizecircularribmachine(2)

Producingbydoublejacquardweftknittingmachine(5)

ProducedbyV-bedflatknittingmachine(6)

Producedbydoublecylinderhosierymachine

*2.2.4Knittingaction(1)

Clearing.Thecylinderanddialneedlesmoveouttocleartheplainandribloopsformedinthepreviouscycle.*(2)

YarnFeeding.Theneedlearewithdrawnintotheirtrickssothattheoldloopsarecoveredbytheopenlatchesandthenewyarnisfedintotheopenhooks.*(3)

Knocking-over.Theneedlesarewithdrawnintotheirtrickssothattheoldloopsarecastoffandthenewloopsaredrawnthroughthem.*Ribknittingaction*2.2.4NeedleTimingNeedletimingistherelationshipbetweentheloop-formingpositionsofthedialandcylinderneedlesmeasuredasadistanceinneedlesbetweenthetwostitchcamknock-overpoints.Therearethreekindoftiming:(1)Synchronizedtiming(2)Delayed,rib,orinterlocktiming(3)Advancedtiming

*2.3InterlockFabric2.3.1thestructureInterlockiscomposedoftwo1×1ribfabricslockedtogether.Ithasthetechnicalfaceofplainfabriconbothsidesbutitssmoothsurfacecannotbestretchedouttorevealthereverseloopwales.

*2.3.2thecharacteristics(1)

theappearanceofthefaceandbackisthesame(2)

Extensibilitywidthwiseandlengthwiseareapproximatelythesameassinglejersey(3)

Thefabricdoesnotcurlatedges(4)

Arunwilldevelopinthefabricthedirectionofwhichwillbefromtheendlastknitted.Aninterlockfabricwillrunlessfreelythansinglejerseyorribstructure(5)

Thefabriccanbeunraveledfromtheendlastknitted.Twoyarnsmustberemovedtounravelacompleteknittedcourse(6)

Thethicknessofthefabricisapproximatelytwicethatofsinglejersey(7)

Interlockrelaxesbyabout30-40percent*2.3.2Knitting(1)

Interlockgating.Theneedlesintwobedsmustbeexactlyoppositetoeachothersoonlyoneofthetwocanknitatanyfeeder(2)

Twoseparatecamsystemsineachbed,eachcontrollinghalftheneedlesinanalternatesequence,onecamsystemcontrolsknittingatonefeederandtheotheratthenextfeeder(3)

Theneedlesaresetoutalternately;onecontrolledfromonecamsystemthenextfromtheother,diagonalandnotoppositeneedlesineachbedknittogether(4)

Thetheconventionalinterlockmachinehasneedlesoftwodifferentlengths,longneedlesknitinonecam-trackandshortneedlesknitinatracknearertotheneedleheads.*2.4PurlFabric2.4.1theStructurePurlstructureshaveoneormorewaleswhichcontainbothfaceandreverseloops.Thesemi-circlesoftheneedleandsinkerloopsproducedbythereverseloopintermeshingtendtobeprominentonbothsidesofthestructure.

*2.4.2theCharacteristicsof1×1Purlfabric(1)

Sameappearance,faceandback(similartothebackofsinglejersey).(2)

Highlyextensibleinalldirections.Approximatelytwiceasextensibleassinglejerseyinthelengthdirection.(3)

Thefabricdoesnotcurlattheedges.(4)

Thefabricwillruninthewaledirectionstartingfromeitherend.(5)

Thefabricmaybeunraveledcoursebycoursestartingfromeitherend.(6)

Thefabrictendstobetwoorthreetimesthickerthansinglejersey.*2.4.3theknitting(1)

Withdoubleendedlatchneedlesinsomedoublecylindergarmentlengthcircularmachineorhalf-hosemachineorplatpurlmachine(2)

ByriblooptransferinV-bedflatmachine

*Chapter3FancyStitchinWeftKnitting3.1theFloatStitch3.1.1theStructure

Afloatstitchiscomposedofaheldloop,oneormorefloatloopsandknittedloop.Thefloatorweltstitchshowsthemissedyarnfloatingfreelyonthereversesideoftheheldloopwhichisthetechnicalbackofsinglejerseystructures,butistheinsideofribandinterlockstructure.*Missingisusefulforhidinganunwantedcoloredyarnbehindthefaceloopofayarnofaselectedcolorwhenproducingjacquarddesignsinfaceloopsofdifferedcolors.

FloatJacquardFabricRibJacquardFabric*3.1.2theCharacteristicsofFloatStitch(1)

Structuresincorporatingfloatstitchestendtoexhibitfainthorizontallines;(2)

Theyarenarrowerbecausethewalesaredrawnclosertogether;(3)

Thewidth-wiseelasticityisreduced(4)

Thestabilityofthefabrictendtobebetter;

*3.1.3Knitting(1)

TheKnittingActionAfloatloopisproducediftheneedleneitherclearsnorisfedanewyarn,i.e.,theneedleremainsattherunposition.Thuswhileadjacentneedlesformanewloop,theneedlemakingthefloatloopmerelyretainstheheldloop.

*(2)

TheknittingMachine(a)

Mini-jacquardcircularknittingmachine(mechanicalselecting)(b)

ElectronicJacquardcircularknittingmachine(c)

Computerizedflatknittingmachine(d)

Jacquardhosierymachine*3.2TheTuckstitch3.2.1theStructureAtuckstitchiscomposedofaheldloop;oneormoretuckloopsandknittedloops.ItssidelimbsarenotrestrictedattheirfeetbytheheadofanoldloopandassumeaninvertedVorU-shapedconfiguration.*3.2.2theCharacteristicsofTuckStitch(1)

Tuckloopsreducefabriclengthandlength-wiseelasticitybecausethehigheryarntensiononthetuckandheldloopscausesthemtorobyarnfromadjacentknittedloopsmakingthemsmaller(2)

Providinggreaterstabilityandsharpretention(3)

Thefabricwidthisincreasedbecausethetuckloopspulltheheldloopsdownwardscausingthemtospreadoutwardsandmakingextrayarnavailableforwidth-wiseelasticity*(4)

Fabricdistortionandthree-dimensionalreliefiscausedbytuckstitchaccumulation(5)

Tuckstitchesareemployedinaccordionfabricstotieinthelongfloatsproducedonthebackofsingle-jerseyknit-missjacquard(6)

Producingopenworkeffects,improvingthesurfacetexture(7)

Joiningthetwopieceofplainstructurestogethertoproduceadouble-facefabrics*3.2.3Knitting(1)

Inlatchneedlemachine,whenaneedleholdingitsloopalsoreceivesthenewloop(2)

Inbeardedneedlemachine,whenitsbeardismiss-pressedsothattheoldloopisnotcast-offandremainsasaheldloopinsidethebeardwiththenewlyfedtuckloop

*(3)

Themachinethatcanknittuckstitch(a)

Loopwheelorsinkerwheelframe(b)

Fourormorethan4tracksingleordoublecircularknittingmachinewithlatchneedle(c)

Thejacquardcircularknittingmachinewith3-wayselectingtechnique(d)

Flatknittingmachine(e)

Somehosierymachine

*3.3PlatingFabric3.3.1thestructureAplatedstructurecontainsloopscomposedoftwo(ormore)yarns,oftenwithdifferingphysicalproperties,eachhavingbeenseparatelysuppliedthroughitsownguideorguideholetotheneedlehookinordertoinfluenceitsrespectivepositionrelativetothesurface(technicalface)ofthefabric.Platingcanbeall-overeffectoronselectedstitchesandmaybeusedtoproducesurfaceinterest,coloredpattern,openworklaceortomodifythewearingpropertiesofthestructure.*3.3.2theKnittingPrinciple(1)

Theperfectplatingsothattheunderneathyarndosenotshowor‘flash’ontothesurfaceisdifficult.Themainlycontrollingpointsare:theyarntension,angleoffeedandthealready-formedloops(2)

Theyarnpositionednearesttotheneedleheadshowsonthereversesideoftheneedleloopandthereforeshowsonthesurfaceofreversestitches*3.4theFleecy(laying-in)Fabric3.4.1theStructureandCharacteristicsAin-layyarnisbindtothebackofplainjerseyorplatingfabricusingtuckstitchessothatthisyarnneverknits.Thisisachievedusingacombinationoffloatingandtucking.

*Platingfleecyisnamedasthree-threadfleecyastherearethreeendsofyarnisneeded.

Sincethelaid-inyarnneverknits,itispossibletouseawidevarietyofyarnsforthispurpose,particularlyverythicksoftandrelativelyweekyarns.Aninlayyarnmayhavecountwhichis6-8timesheavierthantheoptimumcountforthatmachinetypeandgaugeundernormalknittingconditions.Thein-laidyarncanbenappedintoapileinthefinishingprocessandthefabriccanbeenusedtomakesportswearandsweatshirts.

*3.4.2theKnittingMachine(1)

producingbythreethreadfleecyknittingmachine(latchneedle)(2)

producingbythemulti-trackcircularknittingmachine(latchneedle)(3)

producingbytheloopwheelorsinkerwheelframe(beardedneedle)*3.5thePlushfabric3.5.1theStructureTheplushstructureconsistsoftheplainloopandelongatedplushsinkerloopswhichshowasapilebetweenthewalesonthetechnicalbackasaresultofhavingbeenformedoveradifferentsurfacetothatofthenormallengthgroundsinkerloopswithwhichtheyareplated.Henkelplushorvelourisachievedduringfinishingbycroppingorshearingtheloopsinbothdirections,toleavetheindividualfibersexposedasasoftvelvetysurfacewhilstthegroundloopsremainintact.*3.5.2Knitting(1)

Insinkertoplatchneedlemachine,thegroundyarnisfedintothesinkerthroatandtheplushyarnfedathigherlevelisdrawnoverthesinkernib.(2)

Insinkerwheelmachine,sinkerswithtwothroatsareemployed,theshallowthroatdrawsalongsinkerloopwiththeplushyarnwhilstthedeeplycutthroatdrawsanormallengthsinkerloopwiththegroundyarn*3.6SliverorHigh-PilefabricSliverorhigh-pilefabricisconsistsofgroundyarnandsliver.Thegroundyarnformsanormalloopandthesliverformsonlyapartlyloop.Theendsofsliverstandoutthesurfaceofthefabricgivingahighpileeffect.Thehigh-pilemachineisaspecialsingle-jerseycircularmachinewhichhassliverfeedswherethesliversaredrawnfromcansandfedtotheneedlethroughthewiresofthedofferroller.Theend-useofthisfabricisman-madefurs,linings,gloves,cushions,industrialpolishersandpaintroller.*3.7looptransferstitch3.7.1Needlelooptransfer(1)

Plainlooptransferstitchesproducedbytransferencefromoneneedletoanotherinthesamebed.(2)

Riblooptransferstitchproducedbytransferencealoopfromoneneedlebedtotheother.(3)Needlelooptransfercanbeproducedbyhandinhandflatknittingmachineorwiththetransferneedleincomputerizedflatmachineautomatically.

*3.7.2Sinkerlooptransferstitch

(PelerineorEyelet)Theaperturesofeyeletareformedatcourseswhereadjacentplainwalesmoveoutwards,asaresultoftheabsenceofconnectingsinkerloops.*Chapter4PatternandSelectionDevicesForproducingafancyfabric,normallythepatternandselectiondevicesmustbeemployed.Thereareseveraltypesofthesedevices:differentlengthsofbuttdifferentbuttpositionpatternwheelmulti-stepselectbuttandelectronicselectetc.*4.1thedifferentbuttpositionInsingleordouble-jerseymulti-cam-track(raceway)machinesneedlebuttsmaybepositionedinoneofbetweentwoandfivetrackswhichateveryfeedpositionhavefixedbutexchangeableknitting,tuckingormissingcams.Insomemachinesacommontopbuttiscontrolledbyastitchcam-track.*4.2multi-stepbuttset-outs*4.3ThePatternwheelThepatternwheelisacheap,simpledeviceoccupyinglittlespaceandisuniqueinemployingseparateraisingcamsintheformofpatternbitstoselectandmoveindividualelements,ifnecessarytothreedifferentpositionsintheirtricks.*4.4ElectronicneedleselectionElectro-magneticneedleselectionhasnowbeenintroducedontoanumberoftypesofknittingmachines.Theelectronicimpulsewhichenergizesanelectro-magnetisusuallyassistedbythefieldofapermanentmagnetandtheminuteselectionmovementisthenmagnifiedbymechanicalmovements.*Chapter5WeftKnittingFabricProductionTherateoffabricproductionisusuallycalculatedintermsoflinearyards(ormeters)perunittime.Fabricproduction=(Coursesperunittime/Coursedensity)×ηCoursedensityisafabricparameterandismeasuredinthecoursesperinch(cpi)orcoursepercentimeter(cpcm).Thenumberofcoursesproducedperunittimeisafunctionofthefabricstructure,thenumberoffeedersonmachineandthemachinespeedintermsofrevolutionsperminute(rpm)ortraversesperminute(tpm).Theefficiency(η)iscalculatedbyobtainingdataconcerningmachinerunningtimeanddowntime.*Example:Asinglejerseyfabricisproducedona28cpimachinehaving32feedersandarotationalspeedof20rpm.Calculatingtheproduction(yards)overa4-hourperiodifthemachineisusuallystationaryfor3minuteseachhour.Solution:Courses/revolution=Feederspermachinerevolution/Feederperknittedcourse

=32/1=32courses/revolutionCourses/4hours=Courses/rev.×rpm×min/hr×4hr=32×20×60×4=153,600courses/4hoursEfficiency(η)=57/60=0.95Production=153,600×0.95/28=5,211.4inches/4hours=144.76Yards/4hours*Chapter5

BasicWarpKnittingPrinciples*5.1TheWarpknittingmachineClassification*

5.1.1TricotmachineAtricotmachineisawarpknittingmachinewhichusesasinglesetofbeardedorcompoundneedles.Thefabricisremovedfromtheneedlesatapproximately90degrees.Thetricotmachinetendstohavefinegauge(28-32npi)andfewerguidebars(2,3or4),producesimpleandfinestructure.*5.1.2RaschelmachineARaschelmachineisawarpknittingmachinewhichusesasinglesetofverticallymountedlatchorcompoundneedles.Thefabricisremovedfromtheneedlesatapproximately150degrees.TheRaschelmachinetendstohavecoarsegauge(16-18npi)andmoreguidebars(6,8,12-48),producenormallycoarseandcomplexstructure.*5.13TwoneedlebarRaschelmachineThetwoneedlebarsRaschelmachineisawarpknittingmachineequippedwithtwosetsofverticallymountedlatchneedles.Thefabricisremovedfromtheneedlesverticallydownwardsbetweenthetwoneedlebars.*5.2TheWarpknittingmachineelements5.2.1WarpBeamsYarnissuppliedtotheneedlesintheformofwarpsheets.Eachindividualwarpsheetisusuallys