外文翻译-- 注塑模具.doc

InjectionMoldsA.BasicmolddesignAninjectionmoldconsistsofatleasttwohalvesthatarefastenedtothetwoplatensoftheinjectionmoldingmachinesothattheycanbeopenedandclosed.Intheclosedposition,theproduct-formingsurfacesofthetwomoldhalvesdefinethemoldcavityintowhichtheplasticmeltisinjectedviatherunnersystemandthegate.Coolingprovisionsinthemoldprovideforcoolingandsolidificationofthemoldedproductsothatitcanbesubsequentlyejected.B.TypesofEjectionForproductejectiontooccur,themoldmustopen.Theshapesofthemoldedproductdetermineswhetheritcanbeejectedsimplybyopeningthetwomoldhalvesorwhetherundercutsmustbepresent.Thedesignofamoldisdictatedprimarilybytheshapeoftheproducttobemoldedandtheprovisionsnecessaryforproductejection.Injection-moldedproductscanbeclassifiedas:1Productswithoutundercuts(e.g.,plaques,strips,half-shells,cups).2Productswithexternalundercutsorlateralopenings(e.g.,spoolsandbobbins,beveragecrates,threadedbolts).3Productswithinternalundercuts(e.g.,threadedclosures,housings).4Productswithexternalandinternalundercuts(e.g.,bumperfascias,electricalandautomotiveinstrumenthousings,cameras,etc.).C.DesignRulesTherearemanyrulesfordesigningmolds.Theserulesandstandardpracticesarebasedonlogic,pastexperience,convenience,andeconomy.Fordesigning,moldmaking,andmolding,itisusuallyofadvantagetofollowtherules.Butoccasionally,itmayworkoutbetterifaruleisignoredandanalternativewayisselected.Inthistext,themostcommonrulesarenoted,butthedesignerwilllearnonlyfromexperiencewhichwaytogo.Thedesignermusteverbeopentomewideasandmethods,tonewmoldingandmoldmaterialsthatmayaffecttheserules.D.TheBasicMold1.MoldCavitySpaceThemoldcavityspaceisashapeinsidethemold,”excavated”(bymachiningthemoldmaterial)insuchamannerthatwhenthemoldingmaterial(inourcase,theplastic)isforcedintothisspaceitwilltakeontheshapeofthecavityspaceand,therefore,thedesiredproductTheprincipleofamoldisalmostasoldashumancivilization.Moldshavebeenusedtomaketools,weapons,bells,statues,andhouseholdarticles,bypouringliquidmetals(iron,bronze)intosandforms.suchmolds,whicharestillusedtodayinfoundries,canbeusedonlyoncebecausethemoldisdestroyedtoreleasetheproductafterithassolidified.Today,wearelookingforpermanentmoldsthatcanbeusedoverandover.Nowmoldsaremadefromstrong,durablematerials,suchassteel,orfromsofteraluminumormetalalloysandevenfromcertainplasticswherealongmoldlifeisnotrequiredbecausetheplannedproductionissmall.Ininjectionmoldingthe(hot)plasticisinjectedintothecavityspacewithhighpressure,sothemoldmustbestrongenoughtoresisttheinjectionpressurewithoutdeforming.2.NumberofCavitiesManymolds,particularlymoldsforlargerproducts,arebuiltforonly1cavityspace(asingle-cavitymold),butmanymolds,especiallylargeproductionmolds,arebuiltwithormorecavities.Thereasonforthisispurelyeconomical.Ittakesonlylittlemoretimetoinjectseveralcavitiesthantoinjectone.Forexample,a4-cavitymoldrequiresonly(approximately)one-fourthofthemachinetimeofasingle-cavitymold.Conversely,theproductionincreasesinproportiontothenumberofcavities.Amoldwithmorecavitiesismoreexpensivetobuildthanasingle-cavitymold,but(asinourexample)notnecessarily4timesasmuchasasingle-cavitymold.Butitmayalsorequirealargermachinewithlargerplatenareaandmoreclampingcapacity,andbecauseitwilluse(inthisexample)4timestheamountofplastic,itmayneedalargerinjectionunit,sothemachinehourcostwillbehigherthanforamachinelargerenoughforthesmallermold.Today,mostmulticavitymoldsarebuiltwithapreferrednumberofcavities:2,4,6,8,12,16,24,32,48,64,96,128.Thesenumbersareselectedbecausethecavitiescanbeeasilyarrangedinarectangularpattern,whichiseasierfordesigninganddimensioning,ormanufacturing,andforsymmetryaroundthecenterofthemachine,whichishighlydesirabletoensureequalclampingforceforeachcavity.Asmallernumberofcavitiescanalsobelaidoutinacircularpattern,evenwithoddnumbersofcavities,suchas3,5,7,9.Itisalsopossibletomakecavitylayoutsforanynumberofcavities,providedsuchrulesassymmetryoftheprojectedareasaroundthemachinecenterlineareobserved.3.CavityShapeandShrinkageTheshapeofthecavityisessentiallythe”negative”oftheshapeofthedesiredproduct,withdimensionalallowancesaddedtoallowforshrinkingoftheplastic.Theshapeofthecavityisusuallycreatedwithchip-removingmachinetolls,orwithelectricdischargemachining(EDM),withchemicaletching,orbyanynewmethodthatmaybeavailabletoremovemetalorbuilditup,suchasgalvanicprocesses.Itmayalsobecreatedbycasting(andthenmachining)certainmetals(usuallycopperorzincalloys)inplastermoldscreatedfrommodelsoftheproducttobemade,orbycasting(andthenmachining)somesuitablehardplastics(e.g.,epoxyresins).Thecavityshapecanbeeithercutdirectlyintothemoldplatesorformedbyputtinginsertsintotheplates.E.CavityandCoreByconvention,thehollow(concave)portionofthecavityspaceiscalledthecavity.Thematching,oftenraised(orconvex)portionofthecavityspaceiscalledthecore.Mostplasticproductsarecup-shaped.Thisdoesnotmeanthattheylooklikeacup,buttheydohaveaninsideandanoutside.Theoutsideoftheproductisformedbythecavity,theinsidebythecore.Thealternativetothecupshapeistheflatshape.Inthiscase,thereisnospecificconvexportion,andsometimes,thecorelookslikeamirrorimageofthecavity.Typicalexamplesforthisareplasticknives,gamechips,orrounddiskssuchasrecords.Whiletheseitemsaresimpleinappearance,theyoftenpresentseriousmoldingproblemsforejectionoftheproduct.Usually,thecavitiesareplacedinthemoldhalfthatismountedontheinjectionside,whilethecoresareplacedinthemovinghalfofthemold.Thereasonforthisisthatallinjectionmoldingmachinesprovideanejectionmechanismonthemovingplatenandtheproductstendtoshrinkontoandclingtothecore,fromwheretheyarethenejected.Mostinjectionmoldingmachinesdonotprovideejectionmechanismsontheinjection(“hot”)side.注：该文选自张晓黎李海梅主编。塑料加工和模具专业英语化学工业出版社，2004注塑模具A基本模具设计一个注塑模具至少包括两半，这些固定在两个盘的注塑机，以便他们能够开启和关闭。在关闭位置，产品形成表面两个半确定模具型腔将其注入塑料熔体通过热流道系统和门。冷却规定提供模具冷却和凝固的成型产品，以便能够随后顺利流出.B注塑的类型产品注射发生时，模具必须打开。制品的形状决定了它是能够被直接开模取出还是必须考虑凹孔的影响。模具的设计是决定模具的形状主要是由该产品将成型的规定和必要的产品注射。注塑产品可分为：1Products不削弱（如斑块，带，半弹，杯）。2Products与外部削弱或侧开口的（例如，线轴和筒子，饮料箱，螺纹螺栓）。3Products内部破坏（例如，线程关闭，外壳）。4Products与外部和内部破坏（例如，保险杠fascias，电器和汽车仪表外壳，照相机等）。C.设计规则设计模具有许多规则。这些规则和标准的做法是根据逻辑，过去的经验，方便，经济的角度考虑的.对于设计，模具制造，成型，按照这些规则通常是有优势的.但是有些时候，它可能更好的工作如果忽视了这种方法而选择可另一种设计原则.在这段文章中，最常见的规则被选择，但设计者将会根据经验去确定应该选择的规则，同时设计者必须想出新的方法和建议去设计新的模具和模具材料，这些可能会影响到这些规则。D.基本模具1.模具型腔空间在模具型腔形状空间内的模具，“挖掘”（由机械加工的模具材料）以这种方式，当成型材料（在目前情况下，塑料）是被迫进入这一领域将采取的形状腔的空间，因此，得到理想的产品.模具的这一原理几乎和人类文明有一样漫长的历史.模具已被用来制造工具，武器，钟声，雕像，和家居用品，通过浇注液态金属（铁，铜）到沙形式。这种模具，这是沿用至今的铸造厂，但是只能使用一次，因为为了在产品固化后将其取出而不得不将其毁坏.今天，我们正在寻找永久铸模，可重复使用。现在的模具都是用坚固的，可回收利用的材料做成的，比如钢铁，软铝或金属合金。某些塑料模具在长期的生活并不需要，因为计划生产量本来就少。在注塑成型的（热）塑料注入腔空间用高压，因此，模具必须强大到足以抵制注射压力不变形。2.型腔的数目许多模具，特别是较大的模具产品，是专为只有1腔空间（单腔模具），但许多铸模，尤其是大型的生产模具，建有或更多的型腔，这个原因完全是从经济的角度考虑的。It这样就只需要投入稍微多一点的时间去注入几个型腔而不是仅仅的一个。例如，一个4腔模具只需要（约）的四分之一的时间注入一个单腔模具。总之，产量的增加完全可以根据型腔数目的增加而增加。当然也个拥有多个型腔的模具要远比只有一个型腔的模具昂贵的多，但（因为在我们的例子）不一定就比单腔模具有四倍的产量。而且可能需要有更大机板面积的机器，更好的钳位能力，因为它会使用（在这个例子中）4倍的塑料，它可能需要更大的注射单元，使机器的成本比小的模具的成本更高。今天，大部分多模腔模具都用一定的首选号码标注