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.