1-s2.0-s0169433213018552-main

1、AppliedSurfaceScience288(2014)208–214ContentslistsavailableatScienceDirectAppliedSurfaceSciencejournalhomepage:locateapsuscCrelationbetweencontactsurfacefrictionduringtheopticalglasspolishingN.Belkhir?T.AliouaneD.BouzidL

2、abatyofAppliedopticsInstituteofOpticsPrecisionMechanicsUniversityFerhatAbbasSetif1AlgeriaarticleinfoArticlehisty:Received22February2013Receivedinrevisedfm21September2013Accepted1October2013Availableonline11October2013Key

3、wds:OpticalglassPolishingPressuredistributionSurfacecontactFrictionabstractThisstudyaimstodetermihecrelationbetweenthecontactsurfacethepolishingpressurethefrictioncoefficientduringtheopticalglasspolishing.FthispurposeBK7

4、opticalglasssampleswerepolishedthementionedparametersweremeasuredtofindacrelationbetweenthem.SeveralmethodsofacterizationhavebeenusedthemechanicalprofilometertheAFMinadditionsetupsfmeasuringfcesthecontactsurfacehavebeend

5、evelopedadaptedtothepolishingmachine.Thefoundresultshaveshowntheexistenceofacloserelationshipbetweenthethreeparameterstheinfluenceofeachother.Thishaveallowedtodeducethatduringthepolishingprocessitisveryimptanttocontrolth

6、econtactpressurethepolisherfmaccdingtothepressuredistributionindertoguaranteeaveryhighqualityofthepolishedsurface.?2013ElsevierB.V.Allrightsreserved.1.IntroductionThereproducibilityofopticalsurfaceswithhighaccuracyisamaj

7、aimoftheopticalindustrydevelopment.Thefreeabrasivespolishingprocessconsistsofafrictionalcontactbetweenthesampletherotatingpolishingpad.Inpolishingslurryofabrasivegrainsizesbelow1?missuppliedonasoftpolishergenerallyusedin

8、thisoperation.Thefineabrasiveparticlesareretainedonthepadsurfaceresilientlyplasticallythewksurfacesarescratchedmicroscopically.Polishingactionsarebyfarsmallerifcomparedwithlappingcontributingtothesuccessfulapplicationsto

9、thebrittlematerials[1].Severalhypotheseswereproposedtodescribethematerialremovalinthepolishingprocess[1–5]butthemostusedisthecombinedhypothesisoftwoactionsamechanicalactiongeneratedbytheabrasivegrainsachemicaloneproduced

10、bythereactionbetweenthesuspensionliquidthepolishedmaterial.Duringthepolishingprocessmaterialremovalishighlyinfluencedbythelocalpressuretherelativespeedbetweenthetoolthewkpiece.Faconstanttoolpressuretheshapechangecanbeeas

11、ilyfound.Howeverthisisnotpossibleinseveralcasesbecauseofthetoolthewkpieceshapesthatarenotgenerallythesametheroughness(overlapbetweenthepolisherthe?Crespondingauth.Tel.:21336844653fax:21336844653.Emailaddresses:(N.Belkhir

12、).sampleasperities)thepresenceofthefcestheaccelerationssimultaneouslyactivatingonthesurfacetobepolished[6–11].ThematerialremovalmodelproposedbySavioetal.[2]showsasatisfactyestimationofthematerialremovalasafunctionofthepr

13、ocessparameters.Thepolishingprocesscanproducedhighlymirrsurface.Materialisremovedataverylowrate.Consequentlythegeometryofthesurfaceneedstobeveryclosetothecrectshapebefepolishing.Thepolishingpressureisappliedontheabrasive

14、throughthecomftablepolishingpad.Thisallowstheabrasivetofollowthecontoursofthewkpiecesurfacelimitstheperationofindividualgrainsintothesurface.Theuseoffineabrasivegrainsinvolvesamoderateabrasiveactionbetweenthegrainsthewkp

15、iece.Thepolishingoperationprincipalconsiststothecontactbetweenthesamplethepolishingpadwiththepresenceoftheabrasivegrains.Duringtheprocessthefrictionofthesamplesurfaceonthepolisherallowstheabrasivegrainstemovethehydratedl

16、ayerfmedonthesurfaceofthesamplebythechemicalreaction.Itwasreptedthattheeffectduetofrictionisproptionaltothecompressivefce[12].Thepolishingrateisassumedtobeproptionaltothefrictionbetweenthesubstratethepad[13].Inpolishingt

17、heremovalmaterialonthesurfaceiscloselyrelatedtothevariationofthefrictioncoefficient[14].BowdenTab[15]havestatedthatthetrueareaofcontactisaverysmallpercentageoftheapparentcontactarea.Thetruecontactareaisfmedbyasperities.W

18、henthenmalfceincreasesmeasperitiescomeintocontacttheaverageareaofeachasperitycontactgrows.Thefrictionalfceisdependenton01694332$–seefrontmatter?2013ElsevierB.V.Allrightsreserved.:dx.doi.g10.1016j.apsusc.2013.10.008210N.B

19、elkhiretal.AppliedSurfaceScience288(2014)208–214060120180240300360420480540600660720780840900960102010801140120051015202530354045Pressure[kPa]Polishingtime[s]Fig.2.Variationofthepressurevs.thepolishingtime.01020108011401

20、2009609008407807206606005404804203603002401801206023456789101112Surfacecontact[cm]Polishingtime[s]Fig.3.Variationofthecontactsurfacevs.polishingtimeoftheglasssample.profileduringthepolishingoperationwhichchangesfromaflat

21、surfacetoanyshapesurface(seeFig.8).3.2.ContactsurfaceFig.3showsthevariationofthecontactsurfaceaccdingtothepolishingtime.ResultsinFig.3showthatthevariationofthecontactsurfaceissimilartothepressureone(seeFig.2).Indeedtheco

22、ntactareaincreasesinthefirstminutestendstostabilizedattheendofthepolishingoperationalowdecreasingisobserved.Thismaybeduetothesurfacequalitythepolishingpressurethepolishingslurrydistributioninthewkingareawhichinfluencesth

23、enaturethepositioningbetweenthepolisherthesamplesurface.Infactatthebeginningoftheoperationtheroughsurfaceofthesampletheexistenceofahighvolumeofslurrywhichrepresentsthevolumeofslurryfeedatthebeginningoftheoperationcausean

24、increaseinthecontactsurface.Howeverthecontactsurfacedecreasesaftersomeminutesbecauseoftheincreasingofthesurfacequality.Table3Chemicalcompositionoftheceriumoxideabrasivegrains(%mass).ElementsSiO2CeO2Cs2OPFLa2O3MgO%mass2.3