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1、Wiredrawing,VermeulenDirk,R#KLPAA/06/197,Basicprinciple,Toreducethediameterofthewire:!thevolume(mass)ofthewireremainsthelengthincreasesthediameterisreduced,V0=V1,V0,V1,d0,d1,L0,L1,Flowofthematerial,how,Thedeformationisdoneinadie,Herethereisthedeformationbutalsofriction,power,Force,Deformation,Inhomo
2、geneousdeformation,shearloss,redundantwork2,Frictionlosscontactlength,Homogenousdeformationreduction,Deformation,Inhomogeneousdeformation,shearloss,redundantwork2,Drawingforcegraph,.PDFboekjeRVdraadtrekken.pdfmore,power,TohavesufficientforcetodrawthewirethroughthedieweneedPOWERPower:comesfromelectri
3、cmotorHowmuchpower?Dependson:Amountofdeformation(=reductionorelongation)5.5to4.75versus5.5to5.00mmStrengthofthewireHICA(0.80%C)versusLOCA(0.05%C)Speed1m/secversus20m/secFrictioninthedie(lubricant,coatingdieangle.),examples,wirerod5.5mmdrawnto4.75mm2m/secLOCA(0.10%C)needs:8.5kWHICA(0.80%C)needs:22.5k
4、WWire2.00mmdrawnto1.8020m/secLOCA(0.10%C)needs:16.7kWHICA(0.50%C)needs:31.9kW,power,9kW?=,power,32kW=,power,Drawing2mmLOCAfrom6.5mm15m/sec(=54km/hor34Miles/hourneeds:175kWnetor235Horsepower,Masteringthedrawingprocess,Ismasteringthewiretemperaturesinceatoohighwiretemperaturedestroysthelubricantfilman
5、dthewireproperties,Wiretemperature,2.Deformationtemperature(homogeneous+redundant)-%reduction-dieangle-%Carbonandtensile3.frictiontemperature-Contactlength(dieanglebearinglength)-lubricant,coating-speed,Temperatureofthewirebeforethedie=coolingofthewireonthepreviouspass,Thetemperatureofthewireafterth
6、edieisthesumof,1.Coolingonthecapstan,Temptop:80C(176F),Tempbottom160C(320F),diebox,5%ofthewireheatGoestothediecooling,60to70%ofthewireheatGoesthecapstancooling,10to15%ofthewireheatGoestotheair,10%ofthewireheatGoeswiththewiretothenextpass,1.Coolingonthecapstan,Coolingcapacityofthecapstan,Dependson-wa
7、terflowthroughthecapstan:litres/sec-temperaturedifferencewaterin/out:deltaTisrelatedtotheheattransmissionofthecapstan(narrowgap,onlysprayers.)-capstansize:morecooling-surface-temperatureofthecoolingwater:15Ccomparedto25C-theamountofwireonthecapstan=timethatthewirespendsonthecapstan-aircooling-airflo
8、waroundthewire:opencapstanforcedaircooling-temperatureoftheairaroundthecapstan(closedcovers!),Example,Capstan620mm,waterflow1.1l/secwatertemperaturein25.4Ctempout29.3Powertocoolingwater:formula:waterflowl/secdeltaTxspecificheatwater1.1(29.3-25.4)4.19=18kWThisis60to70%ofthepowerthatcanbeusedonthiscap
9、stan:18/60%(70%)x100%=25.7-30kWmaxExample:intermediatepass3.40to3mm(.65%C)420m/minneeds26kW-samewireonsmallcapstan:0.7l/sec.=only19kWcoolingpossibleproblem:wiretempwillbetoohigh,Practicalexamples:totalmachine,Capstans400mm,Capstans550-450mm,WiretemperaturesonKochmachine,Higherspeed=morepower;cooling
10、capacityremainsthesame;hencehighertemperatures,Resultsofpowerandcoolingmeasurements,Resultsofmeasurements:comparisonFrigerio-Beng-measuredpower-inaverage5.9kWtocooling=resultsin%Remark:nodifferencewasmadeforthecapstansizehere,Powernotgooddistributed:toomuchpoweronthesmallcapstans,Wiretemperatures:in
11、fluenceofdustextraction,6.5LOCAto1.05mm1650m/min,Frigerio:8pass560others460Jupiter:10pass550others450,Heatisaccumulatedinthewire,Wiretemperatures:nodustextraction,Temperatureshigherifdustextractionisswitchedof,Influenceofforcedaircooling,Influenceofaircoolingonmech.properties,Conclusionsaboutcapstan
12、cooling,IfusedpowerishigherthencoolingcapacitytheheatisaccumulatedintothewireHencedrawingproblems+poormechanicalpropertiesThereforedieseriesshouldbecalculatedtakenintoaccountthecoolingcapacityofthecapstans.SmallercapstanshavelesscoolingcapacityDamagedwatersealsinthenarrowgapsystem,incrustationsetc.r
13、educethecoolingcapacityItsimportanttomaintainthecoolinginagoodcondition,Commentsoncooling,Installedelectricalmotorpowerhastobeinaccordancetocoolingcapacityofthecapstan:a61kWmotorona620mmcapstanmakesnosense.Motorwillbeusedintheworstconditions=morelosses.Coolingcapacitycanbeincreasedbyextraaircoolingu
14、pto15%MeasuringthewiretemperatureonthecapstanswithanIRmeterisafastandcheapcontrol,whichshouldbedoneonaregularbaseandalwaysincaseofdrawingproblems.,2.Masterthedeformationtemperature,Reductions:30%forLOCA15to25%forHICATaperedreductions=equalpowerperpassCorrectdieangles,-25%reductionwith6-or10%reductio
15、nwith20givesexcessive(waste)power(=heat),example,2.00mmfrom6.5mmrodLOCA0.10%C15m/sec,3.Heatbyfriction,ThewireistouchingthediesurfaceHencefriction=heatToreducethisfriction:alubricantisusedPurposeistoseparatethetwosurfaces,Masterthefriction=lubrication,Forwiredrawingmin1g/kglubricantfilmisneededtohave
16、agoodseparation,lubrication:thisforwidiadiese.g.4.75mmneedsmin9.3g/m1.00mmneedsmin2g/mAsaruleofthumb:necessaryg/m=2wirefordiamonddies0.5g/kgissufficientThislubricantfilmhastobecomposedof50%FAand50%ofhardcomponentsItsalsonecessarytohaveagoodadhesiontothewiresurface,Compositionofthelubricantfilm,HardcomponentsCanbethecoating:lime,borax,Zn-phosphate(=agoodadhere
