机械制造类专业英语 教案 Module four Die ＆ Mold Tech

EnglishforDieandMoldPAGE7PAGE职业素质拓展课程重庆工业职业技术学院LearningsituationIIIDieDesignSessionOneTransferMoldingTransfermoldingrepresentsafurtherdevelopmentofcompressionmolding.Theuncuredthermosettingmaterialisplacedinaheatedtransferpotorchamber.Afterthematerialisheated,itisinjectedintoheatedclosedmolds.Surveyyourworkplace,canyoudescribethesequenceofoperationsintransfermoldingforthermosettingplastics.Lookthroughthefollowingschematicallyillustration,pleasetrytofillintheblanksaboutwhichstageofeachpicturedescribes?（a） （b） （c）sequenceofoperationsintransfermoldingforthermosettingplastics（a）opentoclose（b）moldclosedandcavitiesfiled（c）moldopenandmoldedpartsejectedSessionTwoPiercingandpunchingdiedesignThepunchforcebuildsuprapidlyduringshearingbecausetheentirethicknessisshearedatsametime.Pleasewritedownthetermsofthefollowingexamplesofthepiercingprocesses.（a）（b）（c）（d）（a）Shearangleblankthicknesspunchdie（b）punchdiebevelshear（c）double-bevelshear（d）convexshearFillintheblankofthepicture.Typicalsingle-stationdieforpiercingholeSessionThreeInjectionMoldingDiscusswithyourteam-matesaboutinjectionmolding.Truefalse1.Injectionmoldingisprincipallyusedfortheproductionofthethermoplasticparts,althoughsomeprogresshasbeenmadeindevelopingamethodforinjectionmoldingsomethermosettingmaterials.TFORMCHECKBOX FORMCHECKBOX2.TheproblemofinjectingameltedplasticintoamoldcavityfromareservoirofmeltedmaterialhasbeenextremelydifficulttosolveforthermosettingplasticswhichcureandhardenundersuchconditionswithinafewminutesTFORMCHECKBOX FORMCHECKBOX3.Theprincipleofinjectionmoldingisquitesimilartothatofdie-castingTFORMCHECKBOX FORMCHECKBOX4.Theprocessconsistsoffeedingaplasticcompoundinpowderedorgranularformfromahopperthroughmeteringandmeltingstagesandtheninjectingitintoamold.TFORMCHECKBOX FORMCHECKBOX5.Afterabriefcoolingperiod,themoldisopenedandthesolidifiedpartejected6.Severalmethodsareusedtoforceorinjectthemeltedplasticintothemold.Themostcommonlyusedsysteminthelargermachinesisthein-linereciprocatingscrew7.Thescrewactsasacombinationinjectionandplasticizingunit.Astheplasticisfedtotherotatingscrew,itpassesthroughthreezonesasshown:feed,compression,andmetering8.Afterthefeedzone,thescrew-flightdepthisgraduallyreduced,forcingtheplastictocompress9.Theworkisconvertedtoheatbyshearingtheplastic,makingitasemifluidmass.Inthemeteringzone,additionalheatisappliedbyconductionfromthebarrelsurfaceTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXSessionFourBendingDieDesignListenandfillintheblank.Minimumbendradiivaryfordifferentmetals;generally,differentannealedmetalscanbebenttoaradiusequaltothethicknessofhemetalwithoutcrackingorweakening.AsR/Tdecreases(theratioofthebendradiustothethicknessbecomessmaller),thetensilestrainattheouterfiberincrease,andthematerialeventuallycracks.Anapproximateformulaforthebendallowance,LbisgivenbyLb=α（R+kT）Fillintheblankwiththecorrespondingsignintheaboveformula.（Lb）－bendallowance,in(mm)（α）－thebendangle(inradians),deg（T）－thesheetthickness,in(mm)（R）－theinsideradiusofbend,in(mm)（k）－0.33whenRislessthan2Tandis0.50whenRismorethan2TLookatthefiguresbelow,pointoutthebendingmethodstheyused.Vdie wipingdieSurveyyourworkplaceandtrytofindoutmorebendingmethods.Lookatthefollowingfigures;pleasedoesyourbestunderstandingthemeaningoftheterms,thendictateforeachother,thengiveeachofthefollowingfigureatopic.V-bendingdieZ-bendingdieThecalculationofbendingforceisasfollows.P=KLST2/WFillintheblankwiththecorrespondingsymbolintheaboveformula.（P）－bendingforce,tons(formetricusage,multiplynumberoftonsby8.896toobtainkilonewtons)（K）－dieopeningfactor:1.20foradieopening16timesmetalthickness,1.33foranopeningofeighttimesmetalthickness（L）－lengthofpart,in（S）－ultimatetensilestrength,tonspersquarein（W）－widthofVorUdie,in（T）－metalthickness,in.SessionFiveExtrusionDiscusswithyourteam-matesaboutextrusion.Truefalse1.Coldextrusion,orheatedtoatemperaturewhichgivesoptimumresultsfortheconditionsapplyingandtheproductrequirements,i.e.hotorwarmextrusion.TFORMCHECKBOX FORMCHECKBOX2.Inmostcases,themetalisintheformofasolidorhollowcylinderandismovedinacontainingtoolinthedirectioninwhichtheproductemergesfromthedieapertureTFORMCHECKBOX FORMCHECKBOX3.Mostmetalscanbeextrudedinonewayoranother,butobviouslysomemoreeasilythanothers.TFORMCHECKBOX FORMCHECKBOX4.Thecommonmetalsthatcanbeextrudedatambienttemperaturesarelead,aluminium,copper,lowcarbonsteelsandafewalloysofthesemetals.Thesoftersemi-preciousmetalscanalsobeextrudedcoldifrequired.TFORMCHECKBOX FORMCHECKBOX5.Traditionally,inhotextrusionabilletofmetalisforcedthroughashapedholeatoneendofacontainerbytheactionofarampressingfromtheotherend.Thecontainerboreisofuniformcross-sectionandtheratioofitsareatothatoftheproductisknownastheextrusionratio.Inthiscasetheextrudateleavesthediethroughthehollowram.AlthoughthecontainerboreisnormallyrounditmayalsoberectangulartopermitextrusionofverywideproductsThemaintoolingcomponentsforthehotextrusionprocessatthereforethecontainer,thedieassembly,thedummyblockandthemandrelInforwardrodandtubeextrusionthepunchdoesnotsuffermuchfromwearbutthecompressivestressesaresimilartocanextrusionpunchesTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTFORMCHECKBOX FORMCHECKBOXTherearefourbasicextrusionoperations,discusswithyourgroupmembersandwritethemdownfollowingtheschematicillustration.（a）（b）（c）（d）forwardtube-extrusionbackwardcan-extrusioncompoundextrusiontube-extrusionPleaseworkwithyourteam-matestryingtotranslatethefollowingsentencesintoEnglish.Extrusionistheprocessinwhichmaterialisforcedbycompressiontoflowthroughasuitablyshapedapertureinadie,usuallytogiveaproductofasmallerbutuniformcross-sectionalarea挤压是在压力作用下将金属坯料从凹模上相应形状的孔口中挤压，（使金属产生塑性变形）获得制品的工艺过程。挤压件的尺寸较小，具有相同的横截面。Incanextrusionthepunchishighlystressedbycompressiveandbendingloading,andthesametimesubjectstoheavywearandincreasesintemperatureatthepunchnose在空心件挤压中，凸模在压力和弯曲载荷的作用下产生很高的应力，且磨损严重，凸模前面温度也会（迅速）升高。Normallydieshavetohaveatleastonesupportringastheinternalpressuresarehighenoughtocausetransversecrackingduetotangentialortriaxialstressesrespectively由于切向或轴向压力分别作用使内部压力升高，引发横向破裂时，凹模（外侧）必须至少有一个预紧套圈。Surveyyourworkplaceanddoyourbesttoobservethedifferentkindsofpunchinextrusion,andthengiveoutthedifferenttermsoftheschematicillustration.Punchandpunch/mandrelconfigurationsSessionSixThermoplastic&ThermosettingMoldDesignSurveyyourworkplacewithyourclassmatescarefullyandfindmoreinmold.Lookatthefollowingfigurecarefullyandthentrytowritedowntheterminologyusedinthefigureswithyourteam-mates.Thetypicalstructureoftwo-platemoldSessionSevenDrawingDieDesignPleasetickouttheitemifitcanbemadebydrawingdie.Paperclip（X）filecabinet（X）flanges（X）seams（X）corrugations（√）cylindrical（√）box（√）cup（√）pots（√）pans（√）containers（√）kitchensinks（√）automotivefueltanksWritedownthetermsaboutthefollowingfigure.Drawingprocessonasheet-metalblankFirstdrawingdiewithelasticblankholderListenandfillintheblank.Deepdrawsmaybemadeonsingle-actiondies,wherethepressureontheblankholderismoreevenlycontrolledbyadiecushionorpadattachedtothebedofthepress.Thefollowingisatypicalconstructionofsuchadie.SessionEightCompressionMoldingWhichofthefollowingaremadebycompressionmolding?Pleasetickit.√FORMCHECKBOXdishes√FORMCHECKBOXhandles√FORMCHECKBOXcontainercaps√FORMCHECKBOXfittings√FORMCHECKBOXelectricalandelectroniccomponents√FORMCHECKBOXwashing-machineagitators√FORMCHECKBOXhousing√FORMCHECKBOXfiber-reinforcedpartswithlongchoppedfibersTherearethreetypesofcompressionmoldsinworkplace.Pleasegivealinebetweentherelevantitems.semipositiveforqualityproductionpositiveforhighdensityflash-typeforshalloworflatparts Watchingthefollowingfigurescarefully,thentrytogiveeachofthefollowingfiguresatopic.（a）positive（b）semipositive（c）flash（d）diedesignformakingacompression-moldedpartwithundercutsSessionNineBlankingDieDesignWritedownthepartnameofthefollowingfigure.Asimpleblankingdie1.guidepost2.guidebushing3.stockstock4.uppershow5.lowershoeAinvertedblankingdieSessionTenCompoundDieDesignCompoundDieDesign Severaloperationsonthesamestripmaybeperformedinonestrokeatstationwithacompounddie.Suchcombinedoperationsareusuallylimitedtorelativelysimpleshapes,becauseheyaresomewhatslowandbecausethedies(withincreasingcomplexity)rapidlybecomemuchmoreexpensivethanthoseforindividualshearingoperations. Atypicalexampleismadeinfollowingschematicillustrations:(a)beforeand(b)afterblankingacommonwasherinacompounddie.Notetheseparatemovementsofthedie(forblanking)andthepunch(forpunchingtheholeinthewasher).(c)Schematicillustrationofmakingawasherinaprogressivedie.（c）schematicillustrationofacompounddie Groupactivity.Workwithyourgroup