已阅读5页,还剩5页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
1CharacteristicsofStampingandPropertiesofSheetMetalForming1overviewStampingisakindofplasticformingprocessinwhichapartisproducedbymeansoftheplasticformingthematerialundertheactionofadie.Stampingisusuallycarriedoutundercoldstate,soitisalsocalledstamping.Heatstampingisusedonlywhentheblankthicknessisgreaterthan8100mm.Theblankmaterialforstampingisusuallyintheformofsheetorstrip,andthereforeitisalsocalledsheetmetalforming.Somenon-metalsheets(suchasplywood,micasheet,asbestos,leather)canalsobeformedbystamping.Stampingiswidelyusedinvariousfieldsofthemetalworkingindustry,anditplaysacrucialroleintheindustriesformanufacturingautomobiles,instruments,militarypartsandhouseholdelectricalappliances,etc.Theprocess,equipmentanddiearethethreefoundationalproblemsthatneededtobestudiedinstamping.Thecharacteristicsofthesheetmetalformingareasfollows:(1)Highmaterialutilization(2)Capacitytoproducethin-walledpartsofcomplexshape.(3)Goodinterchangeabilitybetweenstampingpartsduetoprecisioninshapeanddimension.(4)Partswithlightweight,high-strengthandfinerigiditycanbeobtained.(5)Highproductivity,easytooperateandtorealizemechanizationandautomatization.Themanufactureofthestampingdieiscostly,andthereforeitonlyfitstomassproduction.Forthemanufactureofproductsinsmallbatchandrichvariety,thesimplestampingdieandthenewequipmentsuchasastampingmachiningcenter,areusuallyadoptedtomeetthemarketdemands.Thematerialsforsheetmetalstampingincludemildsteel,copper,aluminum,magnesiumalloyandhigh-plasticityalloy-steel,etc.Stampingequipmentincludesplateshearpunchingpress.Theformershearsplateinto2stripswithadefinitewidth,whichwouldbepressedlater.Thelatercanbeusedbothinshearingandforming.2CharacteristicsofstampingformingTherearevariousprocessesofstampingformingwithdifferentworkingpatternsandnames.Buttheseprocessesaresimilartoeachotherinplasticdeformation.Therearefollowingconspicuouscharacteristicsinstamping:(1)Theforceperunitareaperpendiculartotheblanksurfaceisnotlargebutisenoughtocausethematerialplasticdeformation.Itismuchlessthantheinnerstressesontheplateplanedirections.Inmostcasesstampingformingcanbetreatedapproximatelyasthatoftheplanestressstatetosimplifyvastlythetheoreticalanalysisandthecalculationoftheprocessparameters.(2)Duetothesmallrelativethickness,theanti-instabilitycapabilityoftheblankisweakundercompressivestress.Asaresult,thestampingprocessisdifficulttoproceedsuccessfullywithoutusingtheanti-instabilitydevice(suchasblankholder).Thereforethevarietiesofthestampingprocessesdominatedbytensilestressaremorethandominatedbycompressivestress.(3)Duringstampingforming,theinnerstressoftheblankisequaltoorsometimeslessthantheyieldstressofthematerial.Inthispoint,thestampingisdifferentfromthebulkforming.Duringstampingforming,theinfluenceofthehydrostaticpressureofthestressstateinthedeformationzonetotheforminglimitandthedeformationresistanceisnotsoimportantastothebulkforming.Insomecircumstances,suchinfluencemaybeneglected.Eveninthecasewhenthisinfluenceshouldbeconsidered,thetreatingmethodisalsodifferentfromthatofbulkforming.(4)Instampingforming,therestrainactionofthedietotheblankisnotseversasinthecaseofthebulkforming(suchasdieforging).Inbulkforming,theconstraintformingisproceededbythediewithexactlythesameshapeofthepart.Whereasinstamping,inmostcases,theblankhasacertaindegreeoffreedom,onlyonesurfaceoftheblankcontactswiththedie.Insomeextracases,suchastheformingoftheblankonthe3deformingzonecontactwiththedie.Thedeformationintheseregionsarecausedandcontrolledbythedieapplyinganexternalforcetoitsadjacentarea.Duetothecharacteristicsofstampingdeformationandmechanicsmentionedabove,thestampingtechniqueisdifferentformthebulkmetalforming:(1)Theimportanceorthestrengthandrigidityofthedieinstampingformingislessthanthatinbulkformingbecausetheblankcanbeformedwithoutapplyinglargepressureperunitareaonitssurface.Instead,thetechniquesofthesimpledieandthepneumaticandhydraulicformingaredeveloped.(2)Duetotheplanestressorsimplestrainstateincomparisonwithbulkforming,moreresearchondeformationorforceandpowerparametershasbeendone.Stampingformingcanbeperformedbymorereasonablescientificmethods.Basedontherealtimemeasurementandanalysisonthesheetmetalpropertiesandstampingparameters,bymeansofcomputerandsomemoderntestingapparatus,researchontheintellectualizedcontrolofstampingprocessisalsoinproceeding.(3)Itisshownthatthereisacloserelationshipbetweenstampingformingandrawmaterial.Theresearchonthepropertiesofthestampingforming,thatis,formingabilityandshapestability,hasbecomeakeypointinstampingtechnologydevelopment,butalsoenhancesthemanufacturingtechniqueofironandsteelindustry,andprovidesareliablefoundationforincreasingsheetmetalquality.3CategoriesofstampingformingManydeformationprocessescanbedonebystamping,thebasicprocessesofthestampingcanbedividedintotwokinds:cuttingandforming.Cuttingisashearingprocessthatonepartoftheblankiscutfromtheother.Itmainlyincludesblanking,punching,trimming,partingandshaving,wherepunchingandblankingarethemostwidelyused.Formingisaprocessthatonepartoftheblankhassomedisplacementfromtheother.Itmainlyincludesdeepdrawing,bending,localforming,bulging,flanging,necking,sizingandspinning.Insubstance,stampingformingissuchthattheplasticdeformationoccursinthe4deformationzoneofthestampingblankcausedbytheexternalforce.Thestressstateanddeformationcharacteristicofthedeformationzonearethebasicfactorstodecidethepropertiesofthestampingforming.Basedonthestressstateanddeformationcharacteristicsofthedeformationzone,theformingmethodscanbedividedintoseveralcategorieswiththesameformingpropertiesandbestudiedsystematically.Thedeformationzoneinalmostalltypesofstampingformingisintheplanestressstate.Usuallythereisnoforceoronlysmallforceappliedontheblanksurface.Whenisassumedthatthestressperpendiculartotheblanksurfaceequalstozero,twoprincipalstressesperpendiculartoeachotherandactontheblanksurfaceproducetheplasticdeformationofthematerial.Duetothesmallthicknessoftheblank,itisassumedapproximatelythetwoprincipalstressesdistributeuniformlyalongthethicknessdirection.Basedonthisanalysis,thestressstateandthedeformationcharacteristicsofthedeformationzoneinallkindsofstampingformingcanbedenotedbythepointsinthecoordinatesoftheplaneprincipalstressesandthecoordinatesofthecorrespondingplaneprincipalstrains.4RawmaterialsforstampingformingTherearealotofrawmaterialsusedinstampingforming,andthepropertiesofthesematerialsmayhavelargedifference.Thestampingformingcanbesucceededo
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 2022年唐山市农业科学研究院选聘工作人员考试试卷及答案解析
- 2022年南阳内乡县招聘事业单位工作人员考试试卷及答案解析
- 2022年吉林大学第一医院工作人员招聘考试试卷及答案解析
- 2022年汉中市公安局南郑分局交通警察大队考试试卷及答案解析
- 2022年防城港市市本级城镇公益性岗位开发计划考试试卷及答案解析
- 2023年福建海峡银行福建福州仓山支行社会招聘考试真题及答案
- 残疾人家属支持-箱庭疗法04
- 学校领导接待群众来访实施方案范文
- 酶生物合成的基本理论
- 良性前列腺增生诊断治疗
- 信达资产管理公司最全资料
- 光固化有机硅材料
- 解决问题的策略-转化
- ATS子系统设备调试(其他功能试验)课件
- 上海中心大厦BIM应用案例
- 部编人教版小学语文三年级下册阅读理解选择题专项训练试题及答案(全套)
- 工程施工火灾危险源辨识与风险评价
- 互联网+大学生创新创业大赛项目策划书--共享乡村振兴项目创业计划书
- CRH2型动车组牵引电动机概述
- dsa技师试题1全国大型医用设备工程技术人员上岗资质考核试卷DSA
评论
0/150
提交评论