Leistrize關(guān)于雙螺桿性能提高的一些細(xì)節(jié)5Elliott-TipsforOptimizingTSEPerformance

TipsforOptimizing

Twin-ScrewExtruderPerformanceThermalInsulatorGasketAfterFeedBarrel Minimizesheattransferfrombarrel#2tofeedbarrel Allowsfeedbarreltoruncooler Allowsbarrel#2torunhotterSetZones#1toHigherTemperaturestoDecreaseWearofPlasticatingScrewElements Useheattosupplymoreenergy,tolessenthemechanical workloadonthescrewelements Newton’s3rdlaw:Ifkneadersapplyforcetomeltthepellets, thepelletsapplyanequal/oppositeforcetothekneaders

Elevatingzone1&2tempswillusuallynotincreasetheTmSideStuffingofPowders Useback-venting Makedropheightasshortaspossibletoavoidfluidizing Choosefeederagitationtypetopreservepowderdensity Makesurestufferhopperisventedadequately Groundallhoppers/chutestodrainstaticelectricity Ifcakingpersistsusecompressedair“blaster”onatimerInsulateMeltPipesandDiesAdvantages: Eliminates“coldspots”duetounevenheatercoverage Stopszonefromcyclingupanddown Initialheat-upisfaster Saferforoperators,reducesburnincidentsDieLipBuildupWaysToMinimizeIt: Coatouterlipsurfaceswithmoldrelease Installvacuumboxtosuctionawayvapors Reducedie/melttemp. TryadditivessuchasstearatesChangetoaHighPressurePumpforMoreEfficientBarrelCooling Processismostlyexothermic(generatesheat) Constantzonetemperatureoverrides Highpressuredeliveryinducesturbulentflowinstead oflaminarflow Turbulentflowinhibitsfoulingfromscalebuild-up Pumpsareavailablewhichproduce120psi. (standard =30-60psi)SetBarrelCoolingWaterTemp.at120°FWhyWouldYouDoThis? Processisnotveryexothermic Heatzonestendtocycleupanddownallday CanresultinmuchsmoothertemperaturecontrolAcidFlushingofBarrelCoolingBores Preventsscalebuild-upinbarrels Improvesheattransfer Onlytakestwohoursaboutevery3-4months CirculatorunitisinexpensiveLaserBarrelAlignment Screwsorbarrelsarewearingatanunusuallyhighrate&/orwith anabnormalpattern Shaftskeepbreakingforunexplainedreasons Extrudervibratesmorethannormal ScrewsaredifficulttoslideinoroutofdrivecouplingsSwitchtoSyntheticGearOil

Syntheticoilis“slipperyer,”=lessfriction Gears,bearings,andsealslastlonger Gearboxrunscoolerandquieter Doesn’tloseviscosityfrommechanicalshearing Maintainshigherviscosityathightemperatures Improvesoverallefficiencyofgearbox MobilSHC600seriesisrecommendedtypeAnti-SeizeGettingscrewelementsofftheshaftsiseasierw/therightanti-seize:FuchsGleitmo820

It’sawhitegrease……veryslippery Ratedfor1150oc! Willnotsolidifylikecopper-basedanti-seize AvailablefromFuchsLubricantsintheU.S.PurgingTechniques

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Chemicalormechanicalabrasivepurge?Orboth?

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Testseveralcommercialpurgematerialsvs.home-brewed

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Purgeoften….…don’tallowmaterialtoget“bakedon”!

·Unboltdieandremovescreensifatallpossible

·Ifdieisleftinplace,increasediezonetempby30C

·Runoldmaterialcompletelyoutofmachineuntilempty

·Whilepurging,alternatescrewRPMfromverylowtohighfor1minuteatatime

Home-BrewedExtruder/DieCleanoutMethodsMix#1:50%Poly,50%DiatomaceousEarth Diatomaceousearthisfinely-milledfossilizedshellsoftiny seaorganismswhichgivesascouringeffect SometimesgetsridofdielinesMix#2:PolyWithKitchenCleanserandWater MixaslurryofwaterandthreeorfourcansofCometor Ajaxkitchencleanser,inabucket Feedpolyatnormalpurgerateand temperatures Slowlypourcleaningslurryintomainfeed WaterwillflashtosteamforadditionalcleaningactionEfficientcolor/productchangeovers·Knowhowcriticalcleanlinessistothenextproducttoberun·Ifpossible,planrunsinorderofdecreasingcleanlinessrequirements·Havewrittenpurgingorstrip-downprocedurestoruneachproduct

·Usetherightsizeextruderforthelotsize

·Helpoperatorsorganizenecessarytools,cleaningsupplies,screens,dieplatesoutneartheextruder

·Studyrawmaterial/endproductflowinandout.Trytoarrangeittominimizeoperatoreffort

Warmup/cooldowntoavoiddegradation

·Startheatinguponlyasfarinadvancetoallowadequatesoaktime

·Whenshuttingdown,fillextruder/dietomax.possiblewithinertpolymer(likeHDPE)to“seal”it

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Insteadofallowingextrudertocoolslowly,openallsolenoidvalvesand“crashcool”usingwater

Avoidingcross-contamination·

Dustcontroliscritical:airborne,floor,mezzanine,equipment

·Washdownfeedercomponentsbetweenruns

·Evaluateifpurgingisadequate.Ifnot,removedieandscrews

·Keepallmaterialcontactsurfacesfreeofgougesandcrevices

·Check“hidden”problemareas:ventinsert/stack,feedport,powderseals·Usemoldreleaseonexteriorofdieandventinsertparts

·Filterwaterusedincoolingbaths

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Haveextrabreakerplates,buckets,scoops,brassscrapers

·Clearlylabelallmaterials,possiblyusingcolorstoavoidmistakes·KeepawayfromtheareaanymaterialsnotbeingusedinthecurrentrunKeyProcessIndicatorsSpecificthruput:kg/hr÷RPM=kgperhourperrpm

-tellsyoudegreeoffillSpecificenergy:kw(applied)=kw(motorrating)x(%torque)x(rpmrunning)x