挤压模具英文课件.ppt

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1、Lecture15ExtrusiondiedesignCourseHour:2Basicrequirements:Graspingtheprinciplesofdiedesign,acquaintingwithdiematerialsEmphasis:DiedesignprinciplesDifficulties:DiedesignprinciplesHotExtrusion—DieDesignDifficultandrequiresalotofexperienceSquaredies(dieangle=90o)giverisetodeadmetalzonesaroundthedieDea

2、dmetalzonesgivebrightfinishestoaluminumalloys(nosurfaceexposedtoair)SpiderdiesproducehollowshapesHowisthecrosssectioncompleted?Extrusion-DieConfigurationsTypicalextrusion-dieconfigurations:(a)diefornonferrousmetals;(b)dieforferrousmetals;(c)dieforT-shapedextrusion,madeofhot-workdiesteelandusedwith

3、moltenglassasalubricantTUBEDIEDESIGNTUBEDIEDESIGNComponentsforExtrudingHollowShapes(a)Anextruded6063-T6aluminumladderlockforaluminumextensionladders.Thispartis8mm(5/16in.)thickandissawedfromtheextrusion(seeFig.15.2).(b)-(d)Componentsofvariousdiesforextrudingintricatehollowshapes.Cross-Sectionstobe

4、ExtrudedPoorandgoodexamplesofcross-sectionstobeextruded.NotetheimportanceofeliminatingsharpcornersandofkeepingsectionthicknessesuniformLecture16ColdextrusionCourseHour:2Basicrequirements:Acquaintingwithcoldextrusionpractice;GraspingdifferenttypesofextrusiondefectsandtheircausesandpreventionEmphasi

5、s:ExtrusiondefectsDifficulties:FormationextrusiondefectsColdExtrusionMorerecentdevelopment(1940's)IncludessomeoperationssimilartoforgingAdvantages–Improvedmechanicalproperties–Workhardening–Goodcontroloftolerances–Improvedsurfacefinish–Eliminationofheatingcosts–HighproductionratesDisadvantages–Hig

6、herstressesrequiremoreexpensivetoolinganddiematerial–Difficultdiedesignessentialtosuccess–LubricationcriticalColdExtrusionTwoexamplesofcoldextrusion.Thinarrowsindicatethedirectionofmetalflowduringextrusion.FurtherExamplesofColdExtrusionProductionstepsforacoldextrudedsparkplug.Across-sectionoftheme

7、talpartshowingthegrainflowpattern.ProductQualityIssuesSurfacecracking(tearing,fir-treecracking,speedcracking,bamboodefects)–Causedby•hightemperature•highspeed•highfriction•Surfaceappearance–Oxides,scratches,disco