thepunch(Rp)anddie(Rd)weredifferentforeachprocess.Theinitialblank-holderforcewasdeterminedastheminimumforcethatcouldpreventthewrinklingoftheblanksandwaskeptconstantduringthetestforeachblank.Ellipticaldeepdrawingtestswereperformedatvariouscornerradiiinatmechanicalpress.ThecornerradiiofthepunchanddieinfirstdrawingwerethethreetypesmentionedinTable.Fig..Dimensionsofthetools(mm)usedinthefirstdrawingprocess.TableCornerradiusandclearance(t=.mm)ProcessCornerradius(mm)Clearance(mm)FirstdrawingRp=,Rd=(.t)RedrawingRp=,Rd=(.t)EllipticaldrawingRp=,Rd=Longside:.,shortside:.TableTestconditionsinfirstdrawingTypeRp(mm)Rd(mm)A.B.C.D.H.Parketal./JournalofMaterialsProcessingTechnology()—..BlankshapeandmeasurementThefinalproductisofanellipticalshapethatconsistsofacirculararcatthelongsideandastraightlineattheshortside.Theblankshapedesignedbytrial-and-errorwa种这些基本模式综合变形。
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