模具 外文翻译 外文文献 英文文献 注塑模

《模具 外文翻译 外文文献 英文文献 注塑模》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、TheInjectionMolding1、TheinjectionmoldingInjectionmoldingisprincipallyusedfortheproductionofthethermoplasticparts,althoughsomeprogresshasbeenmadeindevelopingamethodforinjectionmoldingsomethermosettingmaterials.Theproblemofinjectionamethodplasticintoamoldcavityfromareservoirofmeltedmat

2、erialhasbeenextremelydifficulttosolveforthermosettingplasticwhichcureandhardenundersuchconditionswithinafewminutes.Theprincipleofinjectionmoldingisquitesimilartothatofdie-casting.Theprocessconsistsoffeedingaplasticcompoundinpoweredorgranularformfromahopperthroughmeteringandmeltingsta

3、gesandtheninjectingitintoamold.Afterabriefcoolingperiod,themoldisopenedandthesolidifiedpartejected.Injection-moldingmachineoperation.Theadvantageofinjectionmoldingare：（ⅰ）ahighmoldingspeedadapterformassproductionispossible；（ⅱ）thereisawidechoiceofthermoplasticmaterialsprovidingavariety

4、ofusefulproperties；（ⅲ）itispossibletomoldthreads,undercuts,sideholes,andlargethinsection.2、Theinjection-moldingmachineSeveralmethodsareusedtoforceorinjectthemeltedplasticintothemold.Themostcommonlyusedsysteminthelargermachinesisthein-linereciprocatingscrew,asshowninFigure2-1.Thescrewa

5、ctsasacombinationinjectionandplasticizingunit.Astheplasticisfedtotherotatingscrew,itpassesthroughthreezonesasshown：feed,compression,andmetering.Afterthefeedzone,thescrew-flightdepthisgraduallyreduced,forcetheplastictocompress.Theworkisconvertedtoheatbyconductionfromthebarrelsurface.A

6、sthechamberinfrontofthescrewbecomesfilled,itforcesthescrewback,trippingalimitswitchthatactivatesahydrauliccylinderthatforcesthescrewforwardandinjectsthefluidplasticintotheclosedmold.Anantiflowbackvalvepresentsplasticunderpressurefromescapingbackintothescrewflight.Theclampingforcethat

7、amachineiscapableofexertingispartofthesizedesignationandismeasuredintons.Arule-of-thumbcanbeusedtodeterminethetonnagerequired17foraparticularjob.Itisbasedontwotonsofclampforcepersquareinchofprojectedarea.Iftheflowpatternisdifficultandthepartsarethin,thismayhavetogotothreeorfourtons.M

8、anyreciproca