中文      English
News


Contact us



Contact: Mr.Zhang
Tel:+86-0769-88058006
Mobile:+86-13580979070
E-mail: 13580979070@qq.com
Add.:Yingfeng building A, Taixin road Wanjiang district Dongguan city Guangdong
Production Add.:Zhoushan City Jintang Town West Industrial Zone
Products:Plastic mechanical screw, mixed color Tsui, material tube, spring shot Tsui

Industry news
Position:Home > News > Industry news >

All kinds of special screw selection

时间:12/09/2017View:
  Thebasictypeandmainparametersofthescrewoftheinjectionmoldingmachinearegenerallydividedintothreesections:thefeedingsection,thecompressionsectionandtheequalizationsection.(L1,h1),h1=(0.12-0.14)D,themainfunctionistotransporttherawmaterialtotherearsection.Compressionsection-bottomchanges,themainroleistocompact,meltmaterials,buildpressure.Parametercompressionratioε=h1/h3andL2.AccuratetobeadegreeofchangeA=(h1-h3)/L2.(L3,h3),h3=(0.05-0.07)D,thetemperatureoftheextrudedmaterialisfixedtothetipofthescrew.Forthewholescrew,theparameterL/DaspectratioL/Dprosandcons:L/Dandspeedn,isthescrewplasticizingabilityandtheeffectofanimportantfactor,L/DlargematerialinthebarrelstaytimeLong,isconducivetoplastic,whilepressureflow,leakagereduction,improvetheplasticizingcapacity,whilethetemperaturedistributionofthehigherrequirementsofthematerialfavorable,butafterthelarge,theuseofmanufacturingandassemblyonthenegativeimpact,thegeneralL/DFor(18~20),butthereisanincreasingtrend.OtherpitchS,spiralangleφ=πDtgφ,generalD=S,thenφ=17°40'.φontheplasticizingcapacityoftheimpact,ingeneral,someofthelargertransmissionspeedfaster,sothematerialshapeisdifferent,itsφalsochanges.Powdercanbetakenasφ=25°orso,thecylindermaterialφ=17°orso,theblockmaterialφ=15°orso,butthedifferentφ,theprocessingisalsomoredifficult,sogenerallytake17°40'.Widthe,theviscosityofsmallmaterials,etrytotakesomelarge,toosmalleasytoleak,buttoomuchwillincreasethepowerconsumption,easytooverheat,e=(0.08~0.12)D.Allinall,inthepresentcircumstances,duetothelackofnecessarytestmethods,thedesignofthescrewisnotacompletedesignmeans.
 
  Mostofthemshouldbebasedonthenatureofdifferentmaterials,withexperiencetodevelopparameterstomeetthedifferentneedsoftheplantaregenerallythesame.Hereareafewspecialscrewdesignwithitsmaterialcharacteristicsforabriefintroduction:
 
  one.PCmaterial(polycarbonate)
 
  Features:
 
  ①non-crystallineplastic,nosignificantmeltingpoint,glasstransitiontemperature140°~150℃,meltingtemperature215℃~225℃,moldingtemperature250℃~320℃.
 
  ②highviscosity,moresensitivetotemperature,inthenormalprocessingtemperaturerangeofthermalstabilityisgood,300℃longstayalmostnodecomposition,morethan340℃begantobreakdown,theviscosityoftheshearratelessaffected.
 
  ③strongwaterabsorptionparametersselected:
 
  a.L/Dforitsgoodthermalstability,viscositycharacteristics,inordertoimprovetheplasticizationeffectasfaraspossibletochoosealargeaspectratio,thefactorytake26.Becauseofitswidemeltingtemperaturerange,compressioncanbelonger,sotheuseofgradientscrew.L1=30%fulllength,L2=46%fulllength.
 
  b.Thecompressionratioεisdependentonthemeltingrate,butthecurrentmeltingratecannotbecalculated.AccordingtothePCcanbeprocessedfrom225℃to320℃betweentheprocessingcharacteristics,thegradualchangeinAvaluecanberelativelymoderatePartialvalue,inthecaseofL2larger,ordinarygradientscrewε=2~3,thefactorytake2.6.
 
  c.Becauseofitshighviscosity,strongwaterabsorption,sobeforethehomogenizationsection,thecompressionsectionafterthescrewonthemixingstructuretostrengthenthesolidbeddisintegration,atthesametime,whichcanbeentrainedwaterintogasescape.
 
  d.Otherparameterssuchase,s,φandthegapwiththebarrelcanbethesamewithotherordinaryscrew.
 
  two.PMMA(plexiglass)
 
  Features:
 
  ①glasstransitiontemperature105℃,meltingtemperatureisgreaterthan160℃,decompositiontemperatureof270℃,formingawidetemperaturerange.
 
  ②viscosity,poormobility,thermalstabilityisbetter.
 
  ③strongwaterabsorption.Parameterselection
 
  a.L/Dtoselectthelengthtodiameterratioof20to22ofthetaperedscrew,dependingontheaccuracyofitsproductsgenerallyrequireL1=40%,L2=40%.
 
  b.Compressionratioε,thegeneralselectionof2.3to2.6.
 
  c.Foritsacertaindegreeofhydrophilicity,sothefrontendofthescrewkneadingringstructure.
 
  d.Otherparameterscangenerallybedesignedaccordingtouniversalscrew,andthecylinderclearancecannotbetoosmall.
 
  three.PA(nylon)
 
  characteristic:
 
  ①crystallineplastic,moretypes,differenttypes,themeltingpointisnotthesame,andthemeltingpointrangeisnarrow,generallyusedPA66meltingpointof260℃~265℃.
 
  ②lowviscosity,goodfluidity,therearemoreobviousmeltingpoint,poorthermalstability.
 
  ③waterabsorptioningeneral.Parameterselection
 
  a.L/DSelectthemutantscrewwithanaspectratioof18to20.
 
  b.Compressionratio,thegeneralselectionof3to3.5,whichpreventoverheatingdecompositionh3=0.07~0.08D.
 
  c.Becauseofitslowviscosity,soonlythereverseringandthebarrelclearanceshouldbeassmallaspossible,about0.05,screwandbarrelclearanceofabout0.08,ifnecessary,dependingonthematerial,thefrontcanbeequippedwithanti-Shouldbeself-locking.
 
  d.Otherparameterscanbedesignedaccordingtouniversalscrew.
 
  four.PET(polyester)
 
  characteristic:
 
  ①meltingpointof250℃~260℃,blowmoldinggradePETmoldingtemperatureisbroader,about255℃~290℃.
 
  ②blowngradePETviscosityishigher,thetemperatureontheviscosityoflarge,poorthermalstability.
 
  Parameterselection
 
  ①L/Dgenerallytake20,threedistributionL1=50%-55%,L2=20%.
 
  ②usinglowshear,lowcompressionratioofthescrew,compressionratioε,generallytake1.8to2,whiletheshearoverheatingleadtodiscolorationoropacityh3=0.09D.③screwfrontendwithoutmixingring,topreventoverheating,possessionofmaterials.
 
  ④becauseofthismaterialismoresensitivetothetemperature,andthegeneraluseofrecycledmaterials,inordertoimproveproduction,Iplantisalowshearscrew,itcanbeappropriatetoimprovethemotorspeedtoachievethepurpose.Atthesametimeintheuseofrecycledmaterials(mostofthefilm),thefactoryaccordingtotheactualsituation,inordertoincreasethefeedingcapacityofthefeedingsection,butalsotoincreasetheblankingcaliberinthebarrelslot,etc.,madeabetterEffect.
 
  Fives.PVC(polyvinylchloride)
 
  Thermosensitivematerials,generallydividedintohardandsoft,thedifferenceisthattheamountofplasticizeraddedtotherawmaterials,lessthan10%ofthehard,morethan30%ofthesoft.Features:
 
  ①nosignificantmeltingpoint,60℃softening,100℃~150℃viscousstate,meltingat140℃,whiledecomposition,170℃decompositionquickly,softeningpointclosetothedecompositionpoint,points
------分隔线----------------------------
Home
Products
Screw series
Nozzle series
Barrel series
Flange
screw nozzle head
About us
About us
Honor
Support
Support
Equipment
News
Company news
Industry news
Contact us
Feedback
Contact us
Copyright © 2017 Dongguan City BenSu Injection machine Co. Ltd. Tech:JunMa