模具專業(yè)英語Unit1(1)課件

Unit1InjectionMolding陳顯冰

Overview1.1Theinjectionmolding

Injectionmoldingisamethodofproducingplasticparts.Thisisdonewithaninjectionmoldingmachine.Theshapeoftheparttobeinjectionmoldediscontrolledbythegeometryoftheinjectionmold.Theinjectionmoldingmachinehastwobasicparts;theinjectionunit,whichmeltstheplasticandtheninjectsormovesitintothemold,andtheclampingunit,whichholdstheinjectionmold.注射成型是生產(chǎn)塑料部件的方法。他由注塑機(jī)來完成。注塑成型的部件形狀受到注塑模具的幾何形狀控制。注塑機(jī)有兩個(gè)基本部分；注入裝置，它可融化塑料，然后把塑料注入或移動(dòng)至模具中，鎖模裝置，它可夾住注塑模具。

Injectionmoldingisprincipallyusedfortheproductionofthethermoplasticparts,althoughsomeprogresshasbeenmadeindevelopingamethodforinjectionmoldingsomethermosettingmaterials.Theproblemofinjectingameltedplasticintoamoldcavityfromareservoirofmeltedmaterialhasbeenextremelydifficulttosolveforthermosettingplasticswhichcureandhardenundersuchconditionswithinafewminutes.Theprincipleofinjectionmoldingisquitesimilartothatofdie-casting.Theprocessconsistsoffeedingaplasticcompoundinpowderedorgranularformfromahopperthroughmeteringandmeltingstagesandtheninjectingitintoamold.Afterabriefcoolingperiod,themoldisopenedandthesolidifiedpartejected.Injection-moldingmachinescanbearrangedformanualoperation,automaticsingle-cycleoperation,andfullautomaticoperation.Theadvantageofinjectionmoldingare:Ahighmoldingspeedadaptedformassproductionispossible;Thereisawidechoiceofthermoplasticmaterialsprovidingavarietyofusefulproperties;Itispossibletomoldthreads,undercuts,sideholes,andlargethinsections.

盡管成型某些熱固性材料的方法取得了一定進(jìn)步，但注塑模主要還是用來生產(chǎn)熱塑性塑件。這主要是因?yàn)闊峁绦运芰先垠w在很短的時(shí)間內(nèi)就會(huì)固化和硬化，在從料斗向模具型腔注入熱固性塑料熔體的過程中，也會(huì)出現(xiàn)這種情況，這個(gè)問題一直非常難解決。注塑成型原理和鑄造十分相似。注塑成型的工藝過程包括：首先把料斗中的粉狀或粒狀的塑料混合物依次輸送到計(jì)量區(qū)和熔化區(qū)，然后再注射到模具型腔中，經(jīng)過短時(shí)冷卻后，開模，推出成型塑件。注塑機(jī)分為手動(dòng)、半自動(dòng)及全自動(dòng)操作。注塑模具有以下優(yōu)點(diǎn)：較高的成型速度使大批量生產(chǎn)成為可能；為成型具有不同使用性能的熱塑性材料提供了較寬的選擇；可以成型帶有螺紋的塑件、側(cè)向凹陷的塑件、帶有側(cè)孔的塑件以及較大的薄壁件。1.2Theinjection-moldingstructure

Theinjectionmouldisanassemblyofpartscontainingwithinitan“impression”intowhichplasticmaterialisinjectedandcooled.Itistheimpressionwhichgivesthemouldingitsform.Theimpressionmay,therefore,bedefinedasthatpartofthemouldwhichimpartsshapetothemoulding.注塑模具是由幾部分組合在一起形成成型腔，塑料熔體注入成型腔，并在成型腔內(nèi)冷卻成型。是成型腔形成了塑件的形狀。因此，成型腔被定義為模具的成型部件。Theimpressionisformedbytwomouldmembers:thecavity,whichisthefemaleportionofthemould,givesthemouldingitsexternalform.Thecore,whichisthemaleportionofthemould,formstheinternalshapeofthemoulding.成型腔由兩部分組成：型腔，即模具的母模部分，形成塑件的外部形狀。型芯，即模具的公模部分，形成塑件的內(nèi)部形狀。1)Cavityandcoreplates

Thebasicmouldinthiscaseconsistsoftwoplates.Oneplateissunkintothecavitywhichshapestheoutsideformofthemouldingandisthereforeknownasthecavityplate.Similarly,thecorewhichprojectsfromthecoreplateformstheinsideshapeofthemouldingisclosed,thetwoplatescometogetherformingaspacebetweenthecavityandcorewhichistheimpression.最簡單的模具包括兩塊模板。一塊模板下陷形成型腔，用于形成塑件的外部形狀，這塊模板被稱為型腔板。同理，型芯板上凸起的型芯加工塑件的內(nèi)部形狀。這兩塊板拼合起來，在型腔和型芯之間形成的空間就是成型腔。2)Spruebush

Duringtheinjectionprocessplasticmaterialisdeliveredtothenozzleofthemachineasamelt;itisthentransferredtotheimpressionthroughapassage.Thematerialinthispassageistermedthesprue,andthebushiscalledaspruebush.注塑過程中，塑料以熔融狀態(tài)從注塑機(jī)噴嘴射出，然后流過一通路進(jìn)入模具成型腔。熔體流過的通路稱作主流道，其襯套被稱作澆口套。3)Runnerandgatesystems

Thematerialmaybedirectlyinjectedintotheimpressionthroughthespruebushorformouldscontainingseveralimpressionsitmaypassfromthespruebushholethrougharunnerandgatesystembeforeenteringtheimpression.塑料熔體可能經(jīng)過澆口套直接進(jìn)入模具一個(gè)或幾個(gè)型腔，或者熔體從澆口套流出，經(jīng)過分流道和澆口系統(tǒng)再進(jìn)入型腔。4)RegisterringIfthematerialistopasswithouthindranceintothemould,thenozzleandspruemustbecorrectlyaligned.Toensurethatthisisso,themouldmustbecentraltothemachineandthiscanbeachievedbyincludingaregisterring.如果想讓熔體沒有任何阻礙地進(jìn)入模具，注塑機(jī)的噴嘴和模具主流道必須位于同一軸線上。為確保正確安裝，模具必須安裝在注塑機(jī)的中心部位，（我們可以）通過使用定位圈達(dá)到這一目的。5)Guidepillarsandbushes

Tomouldaneven-walledarticle,itisnecessarytoensurethatthecavityandcorearekeptinalignmemt.Thisisdonebyincorporatingguidepillarsononemouldplatewhichthenentercorrespondingguidebushesintheothermouldplateasthemouldcloses.若加工具有均勻壁厚的塑件，必須確保型腔和型芯在同一軸線上，這可以依靠導(dǎo)柱和導(dǎo)套實(shí)現(xiàn)。導(dǎo)柱安裝在一塊模板上，合模時(shí)進(jìn)入安裝在另一塊模板上對應(yīng)的導(dǎo)套里。6)Fixedhalfandmovinghalf

Thevariousmouldpartsfallnaturallyintotwosectionsorhalves.Hence,thathalfattachedtothestationaryplatenofthemachine(indicatedbythechaindottedline)istermedthefixedhalf.Theotherhalfofthemouldattachedtothemovingplatenofthemachineisknownsimplyasthemovinghalf.Nowithastobedecidedinwhichofthetwohalvesthecavityorcoreistobesituated.Generallythecoreissituatedinthemovinghalfandtheoverridingreasonwhythisisso,isasfollows:各種模具結(jié)構(gòu)（雖然不同，但均）可以劃分為兩個(gè)部分或部件。因此，固定在注塑機(jī)固定板的部分稱為定模部分，同理，固定在注塑機(jī)移動(dòng)板的部分即為動(dòng)模部分。這樣，模具被安裝在注塑機(jī)上。通常型芯安裝在動(dòng)模部分，其原理如下：

Themoulding,asitcools,willshrinkontothecoreandremainwithitasthemouldopens.Thiswilloccurirrespectiveofwhetherthecoreisinthefixedhalforthemovinghalf.However,thisshrinkageontothecoremeansthatsomeformofejectorsystemisalmostcertainlynecessary.

（塑件）冷卻后開模，由于熔體的收縮作用使塑件緊緊地包在型芯上，這與型芯是安裝在定模部分還是安裝在動(dòng)模部分無關(guān)。然而，塑件包緊在型芯上意味著必需使用某種形式的推出系統(tǒng)。如果型芯安裝在動(dòng)模部分，推出系統(tǒng)運(yùn)動(dòng)的動(dòng)力很容易獲得，此外，單型腔模具中，熔體直接進(jìn)入模具內(nèi)部，型腔必須固定在定模部分，型芯必須安裝在動(dòng)模部分。1.3Injection-moldingmachine

Severalmethodsareusedtoforceorinjectthemeltedplasticintothemold.Themostcommonlyusedsysteminthelargermachines(asshowninFigure1.1)isthein-linereciprocatingscrew,asshowninFigure1.2.Thescrewactsasacombinationinjectionandplasticizingunit.Astheplasticisfedtotherotatingscrew,itpassesthroughthreezonesasshown:feed,compression,andmetering.Afterthefeedzone,thescrew-flightdepthisgraduallyreduced,forcingtheplastictocompress.Theworkisconvertedtoheatbyshearingtheplastic,makingitasemifluidmass.Inthemeteringzone,additionalheatisappliedbyconductionfromthebarrelsurface.Asthechamberinfrontofthescrewbecomesfilled,itforcesthescrewback,trippingalimitswitchthatactivatesahydrauliccylinderthatforcesthescrewforwardandinjectsthefluidplasticintotheclosedmold.Anantiflowbackvalvepreventsplasticunderpressurefromescapingbackintothescrewflights.熔融塑料注入模具中通常有幾種方式。在大型注塑機(jī)(如圖1.1所示)上常采用往復(fù)式螺旋注塑的注入方式，如圖1.2所示。螺桿同時(shí)具有注射和塑化的功能。樹脂原料進(jìn)入旋轉(zhuǎn)的螺桿時(shí)，要經(jīng)過圖示的三個(gè)區(qū)域：喂入?yún)^(qū)、壓實(shí)區(qū)和計(jì)量區(qū)。經(jīng)過喂入?yún)^(qū)后，為壓實(shí)樹脂原料，螺桿螺旋部分的深度逐漸降低，同時(shí)傳遞樹脂原料間因剪切作用而產(chǎn)生的熱量，使原料呈半流動(dòng)狀態(tài)。在計(jì)量區(qū)，螺缸表面的加熱裝置對熔體進(jìn)一步加熱。當(dāng)熔體充滿螺桿前部區(qū)域時(shí)，螺桿在熔體壓力的作用下后退，觸動(dòng)限位開關(guān)使液壓缸工作，在液壓力的作用下推動(dòng)螺桿向前運(yùn)動(dòng)，將熔融塑料注射到閉合的模具型腔中。防倒流閥能夠阻止受壓熔體倒流進(jìn)螺桿的螺旋區(qū)。Theclampingforcethatamachineiscapableofexertingispartofthesizedesignationandismeasuredintons.Arule-of-thumbcanbeusedtodeterminethetonnagerequiredforaparticularjob.Itisbasedontwotonsofclampforcepersquareinchofprojectedarea.Iftheflowpatternisdifficultandthepartsarethin,thismayhavetogotothreeorfourtons.注塑機(jī)的鎖模系統(tǒng)所提供的鎖模力由（塑件在分型面的投影）尺寸決定，鎖模力以噸為單位。通?？拷?jīng)驗(yàn)來決定塑件所需要的鎖模力總噸數(shù)，一般在塑件投影面積上每平方英寸需要作用兩噸鎖模力。如果熔體流動(dòng)困難或塑件較薄，鎖模力應(yīng)提高到三到四噸。Manyreciprocating-screwmachinesarecapableofhandingthermosettingplasticmaterials.Previouslythesematerialswerehandledbycompressionortransfermolding.Thermosettingmaterialscureorpolymerizeinthemoldandareejectedhotintherangeof375℃～410℃.Thermoplasticpartsmustbeallowedtocoolinthemoldinordertoremovethemwithoutdistortion.Thusthermosettingcyclescanbefaster.Ofcoursethemoldmustbeheatedratherthanchilled,aswiththermoplastics.許多往復(fù)螺桿式注塑機(jī)能生產(chǎn)熱固性塑料。以前，熱固性塑料由擠出模具或傳遞模具生產(chǎn)。熱固性塑料熔體在模具內(nèi)固化或發(fā)生聚合反應(yīng)，并在溫度為375℃～410℃范圍內(nèi)推出。熱塑性塑料熔體必須在模具內(nèi)冷卻成型，以保證推出時(shí)不發(fā)生變形。這種熱固性循環(huán)速度很快。當(dāng)然，生產(chǎn)熱塑性塑件時(shí)，模具必須被加熱，而不是冷卻。Injection-moldingmachinescanbearrangedformanualoperation,automaticsingle-cycleoperation,andfullautomaticoperation.Theadvantageofinjectionmoldingare:1)ahighmoldingspeedadaptedformassproductionispossible;2)thereisawidechoiceofthermoplasticmaterialsprovidingavarietyofusefulproperties;3)itispossibletomoldthreads,undercuts,sideholes,andlargethinsections注塑機(jī)分為手動(dòng)、半自動(dòng)及全自動(dòng)操作。注塑模具有以下優(yōu)點(diǎn)：較高的成型速度使大批量生產(chǎn)成為可能；為成型具有不同使用性能的熱塑性材料提供了較寬的選擇；可以成型帶有螺紋的塑件、側(cè)向凹陷的塑件、帶有側(cè)孔的塑件以及較大的薄壁件。EXERCISEQuestions1．Whatarethecomponentsofinjection-molding?2．Howdoesthereciprocating-screwinjectionsystemwork?3.Whataretheadvantageofinjectionmolding?ReadingMaterial：BasicsofInjectionMolding

Injectionmoldingisamanufacturingtechniqueformakingpartsfromboththermoplasticandthermosettingplasticmaterialsinproduction.Moltenplasticisinjectedathighpressureintoamold,whichistheinverseoftheproduct'sshape.Afteraproductisdesigned,usuallybyanindustrialdesigneroranengineer,moldsaremadebyamoldmaker(ortoolmaker)frommetal,usuallyeithersteeloraluminium,andprecision-machinedtoformthefeaturesofthedesiredpart.Injectionmoldingiswidelyusedformanufacturingavarietyofparts,fromthesmallestcomponenttoentirebodypanelsofcars.Injectionmoldingisthemostcommonmethodofproduction,withsomecommonlymadeitemsincludingbottlecapsandoutdoorfurniture.注塑成型是一種制造技術(shù)，在生產(chǎn)中用于制造由熱塑性和熱固性塑料材料組成的零部件。熔化的塑料以高壓被注入到了模具中，此過程是形成了產(chǎn)品的相反形狀。通常情況下，在由工業(yè)設(shè)計(jì)師或工程師設(shè)計(jì)完成產(chǎn)品后，由模具制造商（或工具商）制造由金屬（通常是鋼或鋁）組成的模具，然后經(jīng)過精密加工塑造所期望部件的特征。注塑成型廣泛用于制造各種零部件，從最小的零部件到整個(gè)汽車的車身壁板。注塑成型是最常見的生產(chǎn)方法，還通常用于制造某些物品包括瓶蓋和室外家具。1)EjectorStopperAblockthatstopsanejectorplatefromgoingforward[stoppin]1.頂出板制動(dòng)裝置它是阻止頂出板向前運(yùn)動(dòng)的障礙物。2)EjectorPlateEjectorPlateisalsocalledapushplate.Aplatesupportsanedgeofanejectorpinorapushbackpintoejectapartfromamold.Itisejectedbyanejectordeviceofamoldingmachine,andreturnedtotheoriginalpositionwhentheedgeofapushbackpincollideswithacavityplateduringmoldclamping.2.頂出板頂出板也被稱為推出板。此板支撐推頂桿的邊緣或回推銷使零部件從模具中推出。3)StopPinAstopperinstalledtokeepanejectorplatehorizontalorpreventtheejectorplatefromretreatingtoofaranddamagingacoreadaptorplate.3.止動(dòng)銷已安裝的制動(dòng)裝置使頂出板保持水平或防止推出器模板退離過遠(yuǎn)并破壞型芯安裝板。4)PushRodsAshaftlinkedtotheforce(hydraulicormechanical)ofthemoldingmachineinordertogettheejectorplatetowork.4.推桿連接在注塑機(jī)上的軸可產(chǎn)生力使頂出板工作。5)EjectorGuidePins/EjectorGuideBushAnejectorguidepinisalsocalledapushplateguidepinandfunctionsasaguideforslidingofanejectorplate.Becauseanejectorguidebushslides,ahardmaterialisused.Anejectorguidebushisalsocalledapushplateguidebush.Itisacylindricalpartusedtodeterminethepositionbymatchingtheejectorguidepin.5.頂出導(dǎo)銷/頂出導(dǎo)套頂出導(dǎo)銷也被稱為推板導(dǎo)銷，起到頂出板的導(dǎo)軌槽作用。因?yàn)轫敵鰧?dǎo)套滑動(dòng)，所以使用較硬的材料。頂出導(dǎo)套也被稱為推板導(dǎo)套。它是一個(gè)確定與頂出導(dǎo)銷匹配位置的圓柱形部件。6)GasSpring/GasSpringHolderAgasspringforciblypushesbackanejectorplate.Thestrengthofthespringisadjustedbyadjustingthefillingpressure.Whenusingagasspring,makesuretoavoidhightemperature(heatmayexpandgas,deterioratingtheoriginalfunctionsofagasspring).CalculatingFillingPressureTofigureoutfillingpressure(P)fromearlyload(Wo):P=100*Wo/C(C:constant)Tofigureoutcorrespondingspringconstant(K)fromfillingpressure(P)andgasspringconstant(G):K=G*P/100Tofigureoutforcebydisplacement(x)fromthetopofthepistonrod(W):W=P(Gx+C)Seethecatalogofeachmanufacturerforconstant(C)andgasspringconstant(G).6.氣壓彈簧/氣壓彈簧支架氣壓彈簧可用力推回頂出板。彈簧的強(qiáng)度可通過充氣壓力調(diào)節(jié)。當(dāng)使用氣壓彈簧時(shí)，一定要避免高溫。計(jì)算充氣壓力由最初負(fù)荷計(jì)算充氣壓力：P=100*Wo/G由充氣壓力和氣壓彈簧常數(shù)計(jì)算相應(yīng)的彈簧常數(shù)：K=G*P/100由距離活塞桿頂部的位移計(jì)算力：W=P(Gx+C)7)GasSpringHolderAgasspringholderisablockusedtofixagasspringtoanejectorplate.Counterboreprocessforaboltinstallationhole,foritalsofunctionsasapushrod.7.氣壓彈簧支架氣壓彈簧支架是用于把氣壓彈簧固定到頂出板的部件。因?yàn)樗财鹬茥U作用，所以具有用于螺栓連接的沉孔工藝。8)SprueLockPinsApinhastheedgeofwhichisundercuttopullapartinmoldopeningandremoveaspruefromaspruebush.Aftermoldopening,thispinwillfunctionasanejectorpinandejectsthespruefromaapruebush.Alsoitreleasesgascontainedinmoltenplastic.8.澆口鎖銷澆口鎖銷有一個(gè)側(cè)向分型的邊，這樣在模具打開時(shí)可拉出零部件，并可從澆口套中除去一個(gè)澆口。模具打開后，鎖銷將起到頂出銷的作用并從澆口套中推出澆口。同時(shí)也釋放了已熔化塑料中的氣體。ForReference:GlanceattheStructureoftheDie1.Adjustpin(Knock-outbar):Apinorbartypicallyattachedtotheupperportionofthediesetthatforcesthefinishedpieceout.2.Punchholder:Anothertermusedfortheupperdieshoe.3.Backingplate：Aplateusedtosupportthehardwareforthecavityusedinplasticsinjectionmolding.4.Punchplate:Ametalplateontowhichthevario