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08-10-21

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Whythinwallcupmouldsoexpensive?


Whythinwallcupmouldpriceissohigh?Generalspeaking,thinwallcupmouldareusingbettersteel,hotrunner,bettercooling,betterventingandbetterdemoldingeffectiveness.


Thethinwallcupmouldrunsonhighspeedmachinewhichneedswithstandhighpressureduringcupmolding,sothemouldmovingplateandfixedplatethicknessarethickerthancommonmould.Thereneedmanyinterlocksinsidethethinwallmouldtoensureaccuracyandpillarsupporttoavoiddeformandeccentric.Theplasticairlinecupmouldneedusehighhardnesssteel,high-wearandhigh-erosionwithHRC55orabove.Thismeansthinwallmouldsteelcostishigher.


Thehotrunnerdesignislargerthanthecommonplasticmoulds,andatthesametime,needlimitthemeltresidencetometopreventtheresindegradation.Whenthemouldismult-cavities,thegatingbalanceismuchhigherthanthatofcommonmolds.Whichmeansthinwallcupmouldhotrunnercostishigher.


Thin-walledproductsdonotwithstandthelargeresidualstressesduetoheattransferirregularitiesliketraditionalwallthicknessparts.Inordertoensurethedimensionalstabilityoftheproduct,andtocontroltheshrinkageandwarpagewithinanacceptablerange,itisnecessarytostrengthenthecoolingofthemoldtoensurethecoolingbalance.Whichmeansneedbettercoolingdesigntoenhancethecoolingeffect,addinghighconductivitymetalinsertswherenecessarytoaccelerateheattransfer,likeBeCuberylliumcopper.Thecoolingcostishigherthancommonmoulds.


Duetotheshortfillingtimeandhighinjectionspeed,itisveryimportanttofullyexhaustthemold,especiallytheexhaustintheflowfrontgatheringarea,topreventairtrap.Theairisusuallydischargedthroughmouldcores,rams,ribs,studs,andpartingsurfaces.


Theairlinecupwallsandribsareverythin,theyareveryeasytodamage,andtheshrinkageinthethicknessdirectionissmall,theribsandothersmallstructuresarehardtoseparate,toavoidsticking,thereneedusemoreejectorpinswhenthinwallinjectionmolding.


Inaword,thinwallmouldstructureismorecomplicatedthancommonmoulds.That’swhythethinwallcupmouldissoexpensive.


Cutlerymouldexhaustproblem


Intheprocessofproducingcutlerymould,sometimeswillhaveunfilledparts,airbubblesetc,thisiscausedbyairexhaust.


1.Thesourceofairintheinjectioncutlerymold.


(1)Theaircontainedinthegatingsystemandthemouldcavity.(2)Somerawmaterialscontainmoisturethatisnotremovedbydrying,andtheyarevaporizedintowatervaporatahightemperature.(3)Airgeneratedbydecompositionofsomeunstableplasticsduetoexcessivetemperatureduringinjectionmolding.(4)Airformedbyvolatilizationorchemicalreactionofcertainadditivesinplasticrawmaterials.


Poorexhaustoftheknifeandforkmoldwillbringaseriesofhazardstothequalityoftheplasticparts.Themainperformanceisasfollows:


(1)Intheinjectionmoldingprocess,themeltwillreplacetheairinthecavity.Iftheairisnotdischargedintime,themeltfillingwillbedifficult,resultingininsufficientinjectionvolumetofillthecavity.


(2)Excludingtheunsatisfactoryairwillformahighpressureinthecavityandpenetrateintotheplasticinsideunderacertaindegreeofcompression,resultinginqualitydefectssuchaspores,voids,tissuesparseness,andsilverstreaks.


(3)Duetothehighcompressionoftheair,thetemperatureinthecavityrisessharply,whichcausesdecompositionandburningofthesurroundingmelt,causinglocalcarbonizationandcharringoftheplasticpart.Itmainlyoccursatthejunctionofthetwomeltsatthegateflange.


(4)Theairisnotwellremoved,sothatthemeltvelocityenteringeachcavityisdifferent,soflowmarksandfusionmarksareeasilyformed,andthemechanicalpropertiesoftheplasticpartsarelowered.


(5)Duetotheobstructionofairinthecavity,thefillingspeedwillbereduced,themoldingcyclewillbeaffected,andthetaxationefficiencywillbereduced.


Distributionofbubblesinplasticparts


(1)Thebubblesgeneratedbytheaccumulationofairinthemouldcavityofthecutleryspoonareoftendistributedontheoppositepartofthegate.


(2)Bubblesgeneratedbydecompositionorchemicalreactionintheplasticrawmaterialaredistributedalongthethicknessoftheplasticpart.


(3)Thebubblesgeneratedbythevaporizationofresidualwaterintheplasticrawmaterialareirregularlydistributedontheentireplasticpart.


Injectionmoldingisaprocessinwhichamoltenplasticisinjectedintoaclosedmoldhavingarelativelylowtemperaturethroughanozzleunderhighpressure.Boththermoplasticsandthermosetscanbeinjectionmolded.Itcanbeusedtomakevariousbox-typepackagingbucketsandpails,suchasvariouspailsboxesandsmallboxesmould.Forbox-typepackagingcontainers,Chinabucketmoldmanufacturerswillconsiderthefollowingaspectsinbucketmouldstructuraldesign.


1.Thewallthicknessofthebucketmould


Thedesignofthewallthicknessmainlyconsidersthreeaspects:oneisthickness;theotherisuniformity;thethirdisgentletransition.


1Thickness:Thewallthicknessofthebucketismainlydeterminedbyitsuse,plastictype,structureandsoon.Forthermoplastics,generallynotlessthan0.6mm,oftenchoose2~4mm;forthermosettingplastics,becauseofitspoorfluidity,thethicknessislarger,thesmallpiecesare1.6~2.5ram,thelargepiecesare3.2~8mm,themaximumisnomorethan10mm.


2Uniformity:Theuniformityofwallthicknesshasagreatinfluenceonthequalityofthebucket.Ifthethicknessdifferenceofabucketistoolarge,theshrinkagewillbeuneven,causingdefectssuchasdeformationandcrack.Therefore,thestructureshouldbedesignedwithanequalthicknessstructure.


3Smoothtransition:Insomebuckets,somepartsmusthavedifferentthicknessesduetostructuralrequirements,suchasthebucketturningpoint.Atthistime,agentletransitionshouldbeadoptedtoavoidthesuddenchangeofthesection.


2.Improvestiffnessofthebucket


Theplasticisrelativelyflexible,thebucketismadeofpoorrigidity,andtheturnoverboxtypecontainersometimeshasalargeloadcapacity,sovariousmeasuresforimprovingtherigidityshouldbeadoptedinthestructure.


1Addreinforcement:Reinforcementcanenhancethestrengthandrigidityofthecontainer.Thebasicrequirementsfortheribsare:thenumbershouldbemore,thewallthicknessshouldbethin,theheightshouldbeshort,andtheslopeshouldbesufficient.Thebottomoftheribshouldbeacirculararctransition.Thedirectionoftheribshouldbeconsistentwiththeflowdirectiontoimprovetheplastic.toughness;


2Improvetheshape:thebox-shapedbucketismostlyrectangularthin-walledparts,whichareeasytobedeformed.Variousreinforcementmeasuresshouldbetakentoslightlyextendthefoursidewallsofthebuckettoimprovetherigidity;itisastripshapeonthesidewalltopreventdistortion.Enhancement;edgereinforcementattheedgeofthebuckettopreventdeformationofthemouth;bottomreinforcementatthebottomofthebucketdesignedinacorrugated,archedshape.


3Reasonablesupport:Thebottomareaofthebox-shapedbucketislarge,butitisunreasonabletousethewholebottomsurfaceasthesupport.Becausethebottomisslightlycurved,itisnotflat.Therefore,thesurfacesupportshouldbechangedintoalinesupportorapointsupport,andtheconvexsidesupport(ie,theline)Support);raisedfootsupport(iepointsupport);theheightoftheprotrusionisgenerally0.3~0.5mm.


4Corner:Thecorneristheintersectionoftwofacesorthreefaces.Regardlessoftheshapeofthebucket,theintersectionofthefacesmustberounded,whichcangreatlyimprovetherigidityofthebucketandimprovetheplasticfillingmodel.Sex,andcandispersestressandreducedeformation.


3.Demouldingslope


Inordertofacilitatethedemoldingofthemoldedpart,asuitabledraftanglemustbeconsideredwhendesigningthebucket.Thedraftistoosmall,thedemouldingisdifficult,andthesurfaceofthebucketisdamaged;ifitistoolarge,thedimensionalaccuracyisaffected.


Thedraftanglevariesdependingontheshapeoftheplasticpart,thetypeofplastic,themoldstructure,thesurfaceroughness,themoldingmethod,andthelike.Generallyspeaking,thecommonlyusedslopeoftheplasticpartalongthedemoldingdirectionis1o~1.5o,andtheminimumisnotlessthan0.5o.

Householdmoldsareaformoffungus.Therearemanydifferenttypes,andtheycanoccurbothindoorsandoutdoors.


Moldsproducespores,whichspreadbyfloatingaroundintheair.Moldsporesarepresentinallindoorenvironments.Thereisnowaytopreventspores,andtheycanpersistinconditionswheremolditselfcannotgrow.


Moldsporesthriveinenvironmentsthataremoistandwarm,sowhentheylandonadampspot,theybegintogrow.


Moldscangrowonavarietyofdifferentsurfaces,includingfabric,paper,wood,glass,andplastic.Astheygrow,theymaydigestthematerialtheyaregrowingon.






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