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About the temperature principle of twin screw extruder

About the temperature principle of twin screw extruder

  • Categories:Industry News
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  • Time of issue:2020-07-17 15:30
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(Summary description)Next,Iwillgiveyouabriefintroductiontothetemperatureprincipleofthetwinscrewextruder: Extrudableplasticsarethermoplastics,whichmeltwhenheatedandsolidifyagainwhencooled.Therefore,heatisneededduringtheextrusionprocesstoensurethattheplasticcanreachthemeltingtemperature.Sowheredoestheheatofmeltingplasticcomefrom?Firstofall,theweighbridgefeedpreheatingandbarrel/moldheatermayworkandareveryimportantatstartup.Inaddition,themotorinputsenergy,thatis,thefrictionalheatgeneratedinthebarrelwhenthemotorovercomestheresistanceoftheviscousmelttorotatethescrew.Themostimportantheatsourceforallplastics,exceptofcourseforsmallsystems,low-speedscrews,highmelttemperatureplasticsandextrusioncoatingapplications. Inoperation,itisimportanttorealizethatthebarrelheaterisnotactuallythemainheatsource,anditseffectonextrusionmaybesmallerthanweexpected.Thetemperatureoftherearcylinderismoreimportantbecauseitaffectsthetoothingor

About the temperature principle of twin screw extruder

(Summary description)Next,Iwillgiveyouabriefintroductiontothetemperatureprincipleofthetwinscrewextruder: Extrudableplasticsarethermoplastics,whichmeltwhenheatedandsolidifyagainwhencooled.Therefore,heatisneededduringtheextrusionprocesstoensurethattheplasticcanreachthemeltingtemperature.Sowheredoestheheatofmeltingplasticcomefrom?Firstofall,theweighbridgefeedpreheatingandbarrel/moldheatermayworkandareveryimportantatstartup.Inaddition,themotorinputsenergy,thatis,thefrictionalheatgeneratedinthebarrelwhenthemotorovercomestheresistanceoftheviscousmelttorotatethescrew.Themostimportantheatsourceforallplastics,exceptofcourseforsmallsystems,low-speedscrews,highmelttemperatureplasticsandextrusioncoatingapplications. Inoperation,itisimportanttorealizethatthebarrelheaterisnotactuallythemainheatsource,anditseffectonextrusionmaybesmallerthanweexpected.Thetemperatureoftherearcylinderismoreimportantbecauseitaffectsthetoothingor

  • Categories:Industry News
  • Author:
  • Origin:
  • Time of issue:2020-07-17 15:30
  • Views:
Information
Next, I will give you a brief introduction to the temperature principle of the twin screw extruder:
 
Extrudable plastics are thermoplastics, which melt when heated and solidify again when cooled. Therefore, heat is needed during the extrusion process to ensure that the plastic can reach the melting temperature. So where does the heat of melting plastic come from? First of all, the weighbridge feed preheating and barrel/mold heater may work and are very important at startup. In addition, the motor inputs energy, that is, the frictional heat generated in the barrel when the motor overcomes the resistance of the viscous melt to rotate the screw. The most important heat source for all plastics, except of course for small systems, low-speed screws, high melt temperature plastics and extrusion coating applications.
 
In operation, it is important to realize that the barrel heater is not actually the main heat source, and its effect on extrusion may be smaller than we expected. The temperature of the rear cylinder is more important because it affects the toothing or

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About the structure process analysis of twin screw extruder

About the structure process analysis of twin screw extruder

Next,theeditorofJuliwillgiveyouabriefintroductionaboutthestructureandprocessanalysisofthetwin-screwextruder:  1.Plasticizingarea  Theplasticizingzoneistoheattheinjectedresintoformamoltenstate.Theconditionssuchastheheatingtemperatureandtimeinthisregionarenotparticularlylimitedaslongasthefluoropolymerhavingaspecificunstableterminalgroupisinamoltenstate.Inthelatterhalfoftheplasticizationzone,itispreferabletoprovidedevolatilizationholestoremoveatleastapartofvolatilecomponentsundernormalpressureorreducedpressure.Then,thepartialpressureofvolatilecomponentsinthestabilizationregiondescribedlatercanbereduced,andthestabilizationtreatmentcanbeeffectivelypromoted.  2.Stabilizationtreatmentarea  ThestabilizationzoneistomeltandkneadandconvertspecificunstableendgroupsintoaCF2H.Thestabilizationtreatmentareaispreferablyformedbyusingakneadingdiscwithoutpropulsion.Here,melt-kneadingiscarriedoutinthepresenceofwaterandoxygen.Itcandirectlyintroducepurewater,ionexchangewater,etc.orwatervapor;itcanalsobeaccompaniedbythefluoropolymertobetreated.Theamountofwateraddedisthesameasthenumberofunstableterminalgroups,butitisactuallypreferabletosupplyanexcessamount,forexample,atleast10timestheamount.Thepressureinthestabilizationzoneisgenerallycontrolledat0.2~10MPa,andthesettemperatureiscontrolledat280~430℃.Thetimetomaintainpressurizationisusuallylessthan10minutes.  Accordingtotheprincipleoftheextrudertoremoveunstableendgroups,themelt-kneadinginthestabilizationzoneispreferablycarriedoutinthepresenceofoxygeninadditiontothepresenceofwater.Airisusuallyusedintermsofeconomy.Inthepresenceofoxygen,thecarbongeneratedbythemoltenkneadedproductisalsoburned,whichcaninhibitthecoloringofthefluoropolymer.Oxygenisaninertgastotheunstableterminalgroupscarboxylandfluorinatedacylgroups.Duringtheprocessofmeltingandkneading,itcanimprovethedevolatilizationefficiencyofvolatilecomponents.  Three,devolatilizationarea  Thedevolatilizationzoneremoveshigh-temperaturevolatilecomponentsgeneratedbythedecompositionofspecificunstableterminalgroups.Theabsolutepressurevariesaccordingtothemoltenstateofthemoltenkneadedproductandtheoperatingconditionsofthescrewofthekneader.Generally,thepressureisreducedtothepointwherethemoltenkneadedproductdoesnotintrudeintotheexhaustnozzle.Itcanbe0.01to0.1MPa,andthetemperatureiscontrolledat25O~Claughataround.  Inthepresenceofacertainamountofwaterandoxygen,FEPextrudingthroughatwin-screwextrudercaneffectivelyremovetheunstableterminalgroupsofFEP.SimplifiestheprocessingprocessofFEPunstableendgroupsandsavesproductioncosts.Whentheobtainedstabilizedpolymerismelt-formed,nobubblesorvoidsaregeneratedinthefinishedproduct,anditisnotcolored. Formoreinformationabouttwinscrewextruders,pleasevisithttp://www.njjl.com/
发布时间 : 2020-07-30 点击 : 0

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