常用热塑性塑料的成型性能doc.docx

常用热塑性塑料的成型性能doc.docx

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常用热塑性塑料的成型性能doc

常用热塑性塑料的成型性能

Thecommonlyusedthermoplasticplasticformingpropertiesof.Txt48smile,isagreeninspring,isunderthesunhungryashade,autumnisacoolbreeze,awintercampfire.Smileandfaceit,youwillfeelthatlifeissowarm.Thisarticleiscontributedbyrrogin

DOCdocumentsmayexperiencepoorbrowsingontheWAPside.ItisrecommendedthatyoufirstselectTXT,ordownloadthesourcefiletothelocalview.

1:

HDPEPE

1:

crystallineplastics,hygroscopic;2:

goodfluidity,flashgapofabout0.02mm,liquiditypressuresensitive;3:

maymeltfracture,contactwithorganicsolventcrackingcanoccur:

4:

longheatingtimeiseasytodecompose,burn;5:

slowcoolingratemustbefullycooled,moldcoolingsystemshouldbeestablished6:

;shrinkage,shrinkageoflargefluctuation,easyorientation,easilydeformed,effectofcoolingconditionsonthecrystallinityandthemoldshrinkagerateishigh,shouldcontrolthemoldtemperature,ensureproductcoolinguniformity,stability.7:

issuitableforhighpressureinjection,thematerialtemperatureshouldbeuniform,fillingspeedshouldbefast,thepressureshouldbefully8.Notbythegate,orgateneartheresidualstressoflarge,easilyleadtowarpage,deformation.9:

shouldpayattentiontothechoiceofgatelocation,topreventdeformationofshrinkage,areadvisedtosetupcoldmaterial.10:

softeasydemouldingproductswithshallowconcaveside,canbeadoptedForceddemouldingmethod

Two:

polyvinylchloride（rigidPVC）

1:

noncrystallineplastics,absorbingtemperatureofsmall,butinordertoimprovetheliquidityandpreventthegenerationofbubbles,itisadvisabletocarryoutdrying.2:

poormobility,strongthermalsensitivity,easydecomposition,especiallyinthehightemperaturesteelandcoppermetalcontactshouldbe`decomposition,thedecompositiontemperatureof200DEGC,thedecompositionofproducecorrosionandirritantgases.（minimallytoxic）3:

formingasmalltemperaturerange,thetemperaturemustbecontrolledstrictly.4:

issuitableforscrewinjectionmoldingmachineandthroughthenozzle,thenozzlediametershouldbelarge,theneedtopreventthecornerlagmaterial,mustbepromptlyremoved.5:

channelshouldbethickandshort,thegatesectionshouldbelarge,theinjectionsystemthereshallbenodeadends,topreventstagnationofmaterial,6:

cavitysurfacewithchromeplated,thereshouldbeamoldcoolingsystem,moldtemperaturecontrolshouldbesensitiveandaccurate.

Three:

Polypropylene

1:

crystallineplastics,lowerhygroscopicity,possiblemeltfracture,long-termcontactwiththehotmetalwaseasilydecomposed.2:

goodfluidity,overflowthegapbetween0.003mm.3:

coolingspeed,coolingspeedshouldbereasonablecontrolofthegatingsystemandthemold.4:

shrinkage,shrinkagewaverangeeasyorientation.Pronetoshrinkageanddeformation.Theattentionofthe5:

airdepressioncontrolformingtemperature,thetemperaturelowanisotropysignificantly,especiallyatlowtemperatureandhighpressureismorestrong,themoldtemperatureislowerthan50DEGC,mattesurfaceproducts,andpronetoreceivingthebadandflowmarks,temperaturehigherthan90DEGC,easytowarp6:

.Productsofuniformthickness,avoidgapangle,topreventstressconcentration.The7:

orientationability,shouldnotusethegate,orgatenearthehighresidualstress,easytocausethewarpage.

Four:

polystyrene（PS）

1:

fornoncrystallineplastics,goodhygroscopicity,noteasytodecompose,butbrittle,thermalexpansioncoefficient,toproduceresidualstress.2:

goodfluidity,flashgapofabout0.03mm.3:

thicknessshouldbeuniform,notwithinserts,missingangle,angle,thesurfaceshouldbesmoothovereventhen,theremustbesuchasinsert,

Toinsertpreheating.4:

canusescreworplungertypeinjectionnozzlecanbeusedstraightmachine,alsocanuseself-locking.5:

shouldadoptmodestlyhighermoldtemperatures,andlowerinjectionpressure,prolongthetimeofinjectioncanreducetheresidualstresstopreventshrinkageanddeformation（especiallyforthick.Wallproductsmoreeffective）,butthetemperatureistoohighproductspronetocrazing,andthetemperatureistoolowortoomuchamountofreleaseagent,transparentproductstransparencybecomesworse.6:

canbeusedinavarietyofgatesshouldbesmoothtransitionbetweenthegatingsystemandthemoldcavity,topreventdamagetothegatingsystemexceptproductssuspectedofmaterial,draftshouldbemorethan2*,thetopoutputshouldbeevenlydistributed,inordertoavoidtheoccurrenceofproductdeformationorcrackingduetoadverserelease.

Five:

stupidethylenedieneacrylonitrilecopolymer（ABS）

1:

noncrystallineplastics,manyvarieties,mechanicalpropertiesandformabilityofdifferentvarietiesaredifferent,bydeterminingthemoldingmethodandmoldingprocessconditionsaccordingtovarieties.2:

ishygroscopicandmoldingbeforefullydry,requirelessthan0.3%moisturecontentofthesurfacegloss,highrequirement,needlongtimepreheating,drying3:

flow,overflowgapofabout40.04mm;moldingdifficultpolystyrene,shouldadoptthemodestlyhighermoldtemperatures（forheatresistant,highimpactandantiimpacttype,shouldbewithintheallowablerangeofthemaximumtemperature）5:

materialtemperaturehasgreatinfluenceontheproductsthematerial,ifthematerialtemperatureistoohigh,easytomeltdecomposition（decompositiontemperatureof250DEGC）ifthe6:

productsrequirehighprecision,moldtemperatureshouldbe50~60*C,iftheproductrequiressurfaceglossorforheatresistantvariety,moldtemperatureshouldbe60~80degrees.7:

injectionpressureshouldbehigherthanPolystyreneMoldingWhenwashigh,thepluginjectionmachine,thetemperatureshouldbe180~230DEGC,injectionpressuredesirable100~140MPa,usingscrewinjectionmoldingmachine,thetemperatureof160~220DEGCinjectionpressureisdesirable,desirable70~100MPa8:

designshouldpayattentiontothemold,theflowresistanceofthegatingsystemshouldbeassmallaspossible,theformandpositionofgateshouldbereasonableandcantopreventorreducetheweldmarkweldlinenumber,inaddition,thedraftshouldbe2*abovethetopoutputshouldnotbetoolarge,otherwise,moldingormoldingaftermachiningofproducts,productsurfaceiseasytoplay,"white"fortheproductstothephenomenonofwhitehotwaterheating,toeliminatethephenomenonofwhite.

Six:

styreneacrylonitrilecopolymer（SAN）

1;noncrystallineplastics,hygroscopicity,goodthermalstability,noteasytobreakdown.2;liquidityisbetterthanABS,butnotpronetooverflow.3:

productsarepronetocracking（especiallyongate）itisnoteasywithsharpcornersandgaps,molddesign,draftshouldbegreaterandthetopoutputshouldbeevenlydistributed.

Seven:

Polycarbonate

1:

noncrystallineplasticsmolding,goodthermalstability,widetemperaturerange,thetemperatureabove330DEGCtoseriousdecomposition,gasproducedinthedecompositionofnon-toxic,noncorrosive.2:

smallmoistureabsorption,butthewatersensitivityisstrong,mustcarryoutdryingpretreatmentbeforemolding,thewatercontentshallnotexceed0.2%,otherwisetherewillbeacrazetheproblem,bubblesandproductstrengthdecreasedsignificantly.3:

poormobility,sensitivetotemperaturechanges,shrinkageflashgapofabout0.06mm.4:

ifreasonablemoldingconditions,productscanbecontrolledinasmallscalecalledthetolerancerange,andthereforeobtainproductswithhighprecision.

Mayoccurintheformingprocessof5:

meltfracture,andispronetogreaterstress,soweshouldstrictlycontrolthemoldingcondition,aftermoldingshouldadopttheannealingtreatmentontheproducts,inordertoeliminatetheresidualstress.6:

withhighmeltingtemperature,highdegreeofproduct,forthefollowing200gramsshouldadoptthescrewtypeinjectionmachine.Thenozzleshouldadopttheopenextensionnozzle,becausewith7:

degree,liquidityisnotverysensitivetoshearrate,andcoolingspeed,sothepassagetrytodesignthethickandshort,andtrytochoosethedirectgatearea,ringgateorfangate,butshouldavoidexcessivestressandfloworientationlarge,especiallylargeresidualstressnearthegate,whennecessaryby8:

gtabgatethicknessshouldnotbetoolarge,andthewallthicknessshouldbeuniform,avoidsharpcorners,withanotchorinsert,inordertopreventstressconcentrationcausedbycrack,ifitmustbewithThemetalinsertmoldingbeforetheinsertpreheating.9:

barreltemperatureisoneofthemainfactorstocontrolthequalityofproducts,thebarreltemperaturelowtemperatureislow,sotheproductwillbelackofmaterial,surfacecrazingandmattedefects,barreltemperaturehightemperatureishigh,itwillcauseoverflowthephenomenon,andmaketheproductappearcraze,darkspots.Andbubblesandotherdefects.10:

injectionpressureshouldnotbelow,althoughtheplasticcoolingspeed,butifthemoldisprovidedwithaheatingdevice,alsoshouldensurethatproductswithappropriatecoolingtime,11:

molddesign,thedraftshouldbelarger,topoutputdistributionuniform,andpayattentiontosetthecoldmaterialintheproperposition,topreventtheemergenceofwelddefects,lackofstrength,themoldcavityshouldadoptwear-resistingsteel,andquenched.12:

moldshouldgenerallybeheated,moldtemperatureis70~120DEGC,effectofmoldtemperatureontheproductqualitygreatly,Accordingtothewallthicknessoftheconcretevalueofthin-walled80~100C,thickwalledpiecesfrom80~120DEGC,themoldtemperatureistoohighwhentheshrinkagevalue,productelongation,impactresistance,buttheflexuraltensilestreng