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INTERNATIONALJOURNALOFMACHINETOOLSRECEIVEDINREVISEDFORM10SEPTEMBER2002ACCEPTED1OCTOBER2002ABSTRACTINPRECISIONHARDTURNING,AREMAININGPROBLEMISTOMINIMISETOOLWEARTOMAINTAINTHEACCURACYOFGEOMETRYANDSURFACEFINISHTOOLWEARNOTONLYDIRECTLYREDUCESTHEPARTGEOMETRYACCURACYBUTALSOINCREASESCUTTINGFORCESDRASTICALLYTHECHANGEINTHECUTTINGFORCESALSOCAUSESINSTABILITYINTHETOOLMOTION,WHICHRESULTSINMOREINACCURACYPCBNCUTTINGTOOLSAREOFTENUSEDINHARDTURNINGHOWEVER,THEYARESTILLRELATIVELYEXPENSIVECOMPAREDTOORDINARYCARBIDECUTTINGTOOLSINORDERTOATTAINSUFFICIENTLYHIGHPRODUCTIONRATESATMINIMUMCOST,INCREASEOFKNOWLEDGEONCUTTINGTOOLGEOMETRYISNECESSARYTHISARTICLEPRESENTSASTUDYOFTHEEFFECTOFCHAMFERANGLEONTOOLWEAROFPCBNCUTTINGTOOLINTHESUPERFINISHINGHARDTURNINGTHECORRELATIONBETWEENCUTTINGFORCE,TOOLWEARANDTOOLLIFEWEREINVESTIGATEDTHEOPTIMISEDCHAMFERANGLEFORPCBNCUTTINGTOOLISSUGGESTEDFINALLY,THEDISTRIBUTIONOFSTRESSESANDMAXIMUMPRINCIPALSTRESSWORKINGONTHETOOLEDGEWERECALCULATEDWITHTHEUSEOFFINITEELEMENTMETHOD2002ELSEVIERSCIENCELTDALLRIGHTSRESERVEDKEYWORDSHARDTURNINGWEARTOOLLIFEPCBNCUT1INTRODUCTIONTHEDEVELOPMENTOFNEWTOOLMATERIALSINPASTTENYEARS,SUCHASPOLYCRYSTALLINECUBICBORONNITRIDEPCBN,MAKESPRECISIONHARDTURNINGPOSSIBLE,INWHICHTHEHARDNESSOFWORKPIECEISUPTO5862HRCCOMPAREDTOGRINDINGOPERATIONS,PRECISIONHARDTURNINGENABLESRELATIVELYHIGHMATERIALREMOVALRATEANDFLEXIBILITY,WHICHMAKESITMOREANDMOREATTRACTIVETOINDUSTRY,ESPECIALLYTOAUTOMOTIVE,BEARINGANDHYDRAULICINDUSTRIES1INPRECISIONHARDTURNING,ANIMPORTANTCONSIDERATIONISTOMINIMISETOOLWEARTOMAINTAINTHEACCURACYOFGEOMETRYANDSURFACEFINISHTOOLWEARNOTONLYDIRECTLYREDUCESTHEPARTGEOMETRYACCURACYBUTALSOINCREASESCUTTINGFORCESDRASTICALLYTHECHANGEINTHECUTTINGFORCESALSOCAUSESINSTABILITYINTHETOOLMOTIONAND,INRETURN,MOREINACCURACYCURRENTLY,PCBNCUTTINGTOOLSARESTILLRELATIVELYEXPENSIVECOMPAREDTOORDINARYCARBIDECUTTINGTOOLSINORDERTOATTAINSUFFICIENTLYHIGHPRODUCTIONRATESATMINIMUMCOST,OPTIMISATIONOFCUTTINGCORRESPONDINGAUTHORTEL46462228601FAX46462224529EMAILADDRESSJINMINGZHOUMTOVLTHSEJMZHOU08906955/03/SEEFRONTMATTER2002ELSEVIERSCIENCELTDALLRIGHTSRESERVEDDOI101016/S0890695502002146TOOLGEOMETRYISNECESSARYINHARDTURNING,OFTENCHAMFEREDCUTTINGTOOLSAREUSEDDUETOTHEIRHIGHWEDGESTRENGTHANDCHIPPINGRESISTANCECUTTINGTESTSSUGGESTTHATTHECHAMFERANGLEPLAYSANIMPORTROLEINTOOLLIFESINCETHECUTTINGACTIONONLYTAKESPLACESONTHECHAMFERAREAINSUPERFINISHINGHARDTURNINGSEEFIG1,INWHICHVERYSMALLCUTTINGDEPTHANDFEEDRATEAREEMPLOYEDINMOSTCASESCHAMFEREDPCBNCUTTINGTOOLSRESULTINHIGHERFORCESANDSMALLERFLANKWEARTHANPOSITIVEORZERORAKEANGLESONTHEOTHERHAND,LARGECHAMFERANGLESWILLALSORESULTINMOREPLOUGHINGACTIONINSTEADOFCUTTING,ANDTHUSDEGRADESURFACEFINISHANDPRODUCEHIGHERFRICTIONANDWEAR,WHICHRESULTSINSHORTTOOLLIFE2,3,4PREVIOUSRESEARCHINHARDTURNINGHASBEENMOSTLYCONCERNEDWITHCHIPFORMATION,TOOLWEAR,ANDSURFACEINTEGRITYLITTLECONCERNEDWITHEFFECTOFTHETOOLGEOMETRYONTHEPROCESSANDWORKPIECEINTEGRITYEARLYINVESTIGATIONSONTOOLGEOMETRYMAINLYFOCUSEDONTOOLEDGEGEOMETRYANDTHETOOLRAKEGEOMETRY,SUCHASRESTRICTEDCONTACTLENGTHTOOLS5THECUTTINGTOOLWITHNEGATIVECHAMFERANGLEANDPOSITIVEMAINRAKEFACEWASFIRSTPROPOSEDBYHOSHI6,ANDHEFOUNDTHATTHECHAMFERTRAPSTHEWORKMATERIALOVERTHECHAMFEREDEDGE,ANDTHEFORMEDDEADMETALACTSLIKEACUTTINGEDGE,WHICHINCREASESTHETOOLEDGESTRENGTHANDREDUCESTOOLWEAR302JMZHOUETAL/INTERNATIONALJOURNALOFMACHINETOOLSCHAMFERWIDTHWLWAS01MMHONINGEDGERADIUSWAS001MMFLANKANGLESWERE7FIVEVALUESOFCHAMFERANGLE0,10,15,20AND30WEREUSEDFORTHECUTTINGTESTSTHETESTINSERTSCONTAINEDFIG2TOOLGEOMETRYPARAMETERSUSEDINTHECUTTINGTESTS303JMZHOUETAL/INTERNATIONALJOURNALOFMACHINETOOLSMANUFACTURE432003301305LOWCBNCONTENTANDCOMPOSEDOFPCBNTIPSBRAZEDTOAWCSUBSTRATETHEINSERTSWEREDIAGONALANDCORRESPONDEDTOANSICLASSIFICATIONDCMW11T308SWITH08MMNOMINALNOSERADIUSTHESEINSERTSWEREUSEDWITHATOOLHOLDERWITHRAKEANGLEZERODEG,FLANKANGLE7DEGAND0DEGLEADANGLESDJCL1616H1122WORKPIECEMATERIALSTHEWORKPIECEMATERIALUSEDWASBEARINGSTEEL100CR6WITHHARDNESSOF6062HRCTHEWORKPIECEWASMADEASATUBEWITHNOMINALOUTDIAMETER140MMANDINNERDIAMETER100MMTOGUARANTEEUNIFORMHARDNESSTHESTRUCTUREOFMATERIALWASMARTENSITIC23CUTTINGCONDITIONS,TOOLWEARANDCUTTINGFORCEMEASUREMENTCUTTINGTESTSWERECARRIEDOUTONASMT500CNCTURNINGCENTREONEOBJECTIVEOFTHESUPERFINISHINGCUTISTOREPLACEGRINDINGTHEREFORE,FINECUTTINGCONDITIONSWEREUSEDWITHFEEDRATESANDDEPTHOFCUTACHOSENAS005MM/REVAND005MMRESPECTIVELYCUTTINGSPEEDVWASSELECTEDAS160M/MINTOOLLIFEWASDETERMINEDBYMEASURINGMAXIMUMFLANKWEARWIDTHOFTHETOOL,VBTHEFLANKWEARWASMEASUREDUNDERATOOLMICROSCOPETHECUTTINGWASCONTINUEDUNTILTHETOOLFLANKWEARREACHED02MMTHETOOLWEARMEASUREMENTWASTAKENAFTEREVERY10MINCUTTINGCUTTINGFORCESWEREMEASUREDBYAKISTLERFORCEDYNAMOMETER9212ANDSAMPLEDBYAINSTRUNET100DATAACQUISITIONSYSTEMCUTTINGFORCESWEREMEASUREDDURINGTHEWHOLECUTTINGPROCESSBUTONLYTHEMEANVALUESOFSTATIONARYFORCESWEREEMPLOYEDINTHEANALYSISTHREECOMPONENTSOFCUTTINGFORCEWEREMEASUREDTHROUGHOUTTHECUT3RESULTSANDDISCUSSIONCOMPAREDTOCONVENTIONALCUTTING,INSUPERFINISHINGHARDTURNINGTHEDEPTHOFCUTANDFEEDRATEAREVERYSMALLANDTHEWHOLECUTTINGAREAISCONCENTRATEDONARELATIVELYSMALLAREAINTHEFRONTTIPOFTHECUTTINGEDGE,ORINTHEAREAOFCHAMFERZONE,SEEFIG3THECHAMFERZONEFIG3CUTTINGFORCESUNDERDIFFERENTCHAMFERANGLESFIG4TOOLLIFEFORPCBNINSERTSWITHDIFFERENTCHAMFERANGLESFORCESINCREASEWITHTHEINCREASEOFCHAMFERANGLESSINCEALLCUTTINGCONDITIONSAREIDENTICALEXCEPTTHEIRCHAMFERANGLE,THEINCREASEINTHECUTTINGFORCESISMAINLYDUETOFORCESCONTRIBUTEDBYCHAMFERZONETHECHAMFERFORCESINTHEPASSIVEDIRECTIONAREHIGHERANDINCREASEMORERAPIDLYWITHANINCREASEINCHAMFERANGLETHANTHEFORCESINCUTTINGDIRECTIONANDFEEDDIRECTIONINSUPERFINISHINGHARDTURNING,TOGUARANTEETHESURFACEQUALITY,TOOLWEARISUSUALLYLIMITEDTOAVERYSMALLRANGEINTHISINVESTIGATION,TOOLLIFEWASMEASUREDBASEDONA02MMFLANKWEARCRITERIONINORDERTOAVOIDEXCESSIVEWHITELAYERINDUCEDONTHEWORKPIECESURFACEDUETOTHEHIGHERTEMPERATUREUNDERTHELARGEFLANKWEARTOOLLIFERESULTSFORTHECHAMFEREDTOOLEDGEARESHOWNINFIG4CRATERWEARWASALSOOBSERVEDINTHETESTBUTITWASNOTMEASUREDFIG5SHOWSATYPICALFLANKWEARANDCRATERWEARPROFILEONACBNTOOLTHERESULTSOFTOOLFLANKWEARFORDIFFERENTCHAMFEREDEDGESUNDERTHESAMECUTTINGTIMEANDTHETOOLLIFETIMEFORTHESAMEWEARCRITERIAVB02MMAREPRESENTEDINFIG6ASCHAMFERANGLESINCREASETHETOOLLIFEINCREASESTOAMAXIMUMVALUEFORCUTTINGEDGEWITH15CHAMFERANGLEFROMZEROCHAMFERANGLETHETOOLLIFEDIFFERENCEBETWEENTHECUTTINGTOOLWITH15AND30OFCHAMFERANGLEIS53THERESULTSSUGGESTTHATTHEREISANOPTIMISEDCHAMFERANGLE,WHERETHETOOLWILLHAVETHELONGESTTOOLLIFEONONEHAND,TOOLSTRENGTHINCREASESWITHANINCREASEINCHAMFERANGLE,ONTHEOTHERHAND,ANINCREASEDCHAMFERANGLEWILLRESULTINARISEOFTHECUTTINGFORCEFIG5OBSERVEDFLANKWEARANDCRATERWEARPROFILEINHARDTURNING304JMZHOUETAL/INTERNATIONALJOURNALOFMACHINETOOLSMANUFACTURE432003301305FIG6FLANKWEARANDTOOLLIFEOFPCBNINSERTSWITHDIFFERENTCHAMFERANGLES4FEMCALCULATIONTHESTRESSDISTRIBUTIONINTHETOOLDURINGTHECUTTINGWASANALYSEDBYTHEFINITEELEMENTMETHODINTHEANALYSIS,ACROSSSECTIONOFTHETOOLMODELWASDIVIDEDINTOQUADRILATERALELEMENTSTHENUMBEROFELEMENTSANDNODESUSEDWERE2483MEASUREDVALUESOFTHEELASTICMODULUSANDPOISSONSRATIOFORTHESINTEREDBODYOFTHEPCBNTOOLWEREUSEDINTHECALCULATIONSTHEOTHERINPUTDATAFORTHECALCULATIONSARETHEMEASUREDSTRESSESDEVELOPEDINTHETOOLRAKEFACEWHENTHETOOLWORKPIECECONTACTISCOMPLETEDDURINGPRACTICALCUTTINGTHESTRESSESONTHECHAMFERAREAFLANKFACEARERESOLVEDINTONORMALSTRESSANDSHEARINGSTRESSESTHELOADCONDITIONINTHEAREAOFCUTTINGEDGEISILLUSTRATEDINFIG7THECONTACTNORMALANDSHEARSTRESSESARECALCULATEDBASEDONTHEMODELPRESENTEDBYZHOU9THECONTACTSTRESSMODELSAREILLUSTRATEDINFIG8THEDISTRIBUTIONOFTHESTRESSESINTHECUTTINGTOOLCLOSETOTHECUTTINGEDGEWASPRESENTEDINFIG9,WHICHSHOWSTHEMAXIMUMSTRESSESWASINDUCEDJUSTONTHECUTTINGEDGEDURINGTHECUTTINGTHECORRELATIONBETWEENTHESTRESSESANDCHAMFERANGLESISPLOTTEDINTHEFIG10ANDITEXHIBITSTHESAMECORRELATIONPATTERNWITHTOOLWEARANDCHAMFERANGLESFIG7NORMALFORCESANDFRICTIONFORCESINCHAMFERAREAFIG8DISTRIBUTIONOFNORMALSTRESSESANDSHEARINGSTRESSESONTOOLTIPFIG9DISTRIBUTIONOFTHESTRESSESINTHECUTTINGEDGE5CONCLUSIONSCUTTINGEXPERIMENTSANDFECALCULATIONSHAVEBEENCARRIEDOUTINTHISSTUDYINORDERTOINVESTIGATETHEEFFECTSOFCHAMFERANGLEONTHEWEAROFPCBNCUTTINGTOOLSINSUPERFINISHINGHARDTURNINGTHECHAMFERANGLEHASAGREATINFLUENCEONTHECUTTINGFORCEANDTOOLLIFEALLTHREEFORCESCOMPONENTSINCREASEWITHANINCREASEOFTHECHAMFERANGLES,ESPECIALLYINTHELEVELOFPASSIVEFORCEALTHOUGHANINCREASEOFCHAMFERANGLEWILLINCREASETHEWEDGESTRENGTHOFTHEPCBNTOOL,TOOLLIFE,HOWEVER,ITDOESNOTFOLLOWTHESAMETRENDTOOLLIFE,WITHMEASUREDFLANKWEAR02MMASTHECRITERION,REACHESMAXIMUM305JMZHOUETAL/INTERNATIONALJOURNALOFMACHINETOOLSMANUFACTURE432003301305FIG10CORRELATIONOFMAXIMUMPRINCIPALSTRESSESANDCHAMFERANGLESVALUEFORTHETOOLWITH15CHAMFERANGLEANDMINIMUMVALUEFOR30CHAMFERANGLETHEDIFFERENCEINTHELIFETIMEISUPTO53THERESULTSFROMFECALCULATIONINDICATETHATTHEPRINCIPALSTRESSESACTINGONTHECUTTINGEDGEWITH15CHAMFERANGLEHASTHESMALLESTVALUECOMPAREDTOOTHERCUTTINGTOOLS,WHICHSUGGESTSTHATTHEREISANOPTIMALCHAMFERANGLEAROUND15WHERETHECUTTINGTOOLHASMAXIMUMTOOLLIFEACKNOWLEDGEMENTSCOOPERATIONFROMALLPARTNERSINTHEMICROHARDPROJECTISGRATEFULLYACKNOWLEDGEDTHEAUTHORSWOULDALSOLIKETOTHANKEUROPEANCOMMUNITYFORSUPPORTINGTHISPROJECTREFERENCES1DJEFFREY,NMSHREYES,EFFECTOFCUTTINGEDGEGEOMETRYANDWORKPIECEHARDNESSONSURFACERESID