公差与互换性国际标准07Chapter 4 roughness.docx

公差与互换性国际标准07Chapter 4 roughness.docx

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公差与互换性国际标准07Chapter4roughness

Chapter4

Roughness

4.1Generaltermsanddefinitions

•surfaceprofile:

Profilethatresultsfromtheintersectionoftherealsurfacebyaspecifiedplane.

•samplinglengthlr:

LengthinthedirectionoftheX-axisusedforidentifyingtheirregularitiescharacterizingtheprofileunderevaluation.

•evaluationlengthln：

LengthinthedirectionoftheX-axisusedforassessingtheprofileunderevaluation.Ingeneral,evaluationlengthequalfivesamplinglength.

•profilepeak：

Anoutwardlydirected（frommaterialtosurroundingmedium）portionoftheassessedprofileconnectingtwoadjacentpointsoftheintersectionoftheprofilewiththeX-axis.

•profilevalley:

Aninwardlydirected（fromsurroundingmediumtomaterial）portionoftheassessedprofileconnectingtwoadjacentpointsoftheintersectionoftheprofilewiththeX-axis.

•ordinatevalueZ（x）:

Heightoftheassessedprofileatanypositionx.

•profilepeakheightZp:

DistancebetweentheX-axisandthehighestpointoftheprofilepeak.RpisthelargestprofilepeakheightZpwithinasamplinglength.

•profilevalleydepthZv:

DistancebetweentheX-axisandthelowestpointoftheprofilevalley.RvisthelargestprofilevalleydepthZvwithinasamplinglength.

•profileelementwidthXs:

LengthoftheX-axissegmentintersectingwiththeprofileelement.

4.2Evaluationparameter

Amplitudeparameters

•ArithmeticalmeandeviationoftheassessedprofileRa:

ArithmeticmeanoftheabsoluteordinatevaluesZ（x）withinsamplinglength.

•MaximumheightofprofileRz:

SumofheightofthelargestprofilepeakheightZpandthelargestprofilevalleydepthZvwithinasamplinglength.

Spacingparameters

•MeanwidthoftheprofileelementsRSm:

MeanvalueoftheprofileelementwidthsXswithinasamplinglength.

4.3Graphicalsymbolsfortheindicationofsurfacetexture

Basicgraphicalsymbol

Thebasicgraphicalsymbolshallconsistoftwostraightlinesofunequallengthinclinedatapproximately60°tothelinerepresentingtheconsideredsurface,asshowninFigure4-1.ThebasicgraphicalsymbolinFigure4-1shouldnotbeusedalone（withoutcomplementaryinformation）.

Expandedgraphicalsymbols

•Removalofmaterialrequired:

Ifremovalofmaterial—forexample,bymachining—isrequiredforobtainingthespecifiedsurface,abarshallbeaddedtothebasicgraphicalsymbol,asshowninFigure4-2.TheexpandedgraphicalsymbolinFigure4-2shouldnotbeusedalone（withoutcomplementaryinformation）.

•Removalofmaterialnotpermitted:

Ifremovalofmaterialisnotpermittedforobtainingthespecifiedsurface,acircleshallbeaddedtothebasicgraphicalsymbol,asshowninFigure4-3.

Completegraphicalsymbol

•Whencomplementaryrequirementsforsurfacetexturecharacteristicshavetobeindicated,alineshallbeaddedtothelongerarmofanyofthegraphicalsymbolsillustratedinFigures4-1to4-3,asshowninFigure4-4.

•Foruseinthewrittentextof—forexample,reportsorcontracts—thetextualindicationforFigure4-4,a）isAPA1）,forb）itisMRR2）andforc）NMR3）.

Marks:

✧Anyprocessallowed.

✧Materialremovalrequired.

✧Nomaterialremoved.

4.4Compositionofcompletegraphicalsymbolforsurfacetexture

General

Inordertoensurethatasurfacetexturerequirementisunambiguous,itmaybenecessary,inadditiontotheindicationofbothasurfacetextureparameteranditsnumericalvalue,tospecifyadditionalrequirements（e.g.transmissionbandorsamplinglength,manufacturingprocess,surfacelayanditsorientationandpossiblemachiningallowances）.Itmaybenecessarytosetuprequirementsforseveraldifferentsurfacetextureparametersinorderthatthesurfacerequirementsensureunambiguousfunctionalpropertiesofthesurface.

Rulesforcomparisonofthemeasuredvalueswiththetolerancelimits

•Thesurfacetextureoftheworkpieceunderinspectioncanappearhomogeneousorbequitedifferentovervariousareas.

•Thiscanbeseenbyvisualexaminationofthesurface.

•Incaseswherethesurfacetextureappearshomogeneous,parametervaluesdeterminedovertheentiresurfaceshallbeusedforcomparisonwiththerequirementsspecifiedonthedrawingsorinthetechnicalproductdocumentation.

•Ifthereareseparateareaswithobviouslydifferentsurfacetexture,theparametervalueswhicharedeterminedoneachareashallbeusedseparatelyforcomparisonwiththerequirementsspecifiedonthedrawingsorinthetechnicalproductdocumentation.

•Forrequirementsspecifiedbytheupperlimitoftheparameter,thoseseparateareasofthesurfaceshallbeusedwhichappeartohavethemaximumparametervalue.

The16%-rule

•Forrequirementsspecifiedbytheupperlimitofaparameter,thesurfaceisconsideredacceptableifnotmorethan16%ofallthemeasuredvaluesoftheselectedparameter,baseduponanevaluationlength,exceedthevaluespecifiedonthedrawingsorinthetechnicalproductdocumentation.

•Forrequirementsspecifiedbythelowerlimitofasurfaceparameter,thesurfaceisconsideredacceptableifnotmorethan16%ofallthemeasuredvaluesoftheselectedparameter,baseduponanevaluationlength,arelessthanthevaluespecifiedonthedrawingsorinthetechnicalproductdocumentation.

•Todesignatetheupperandthelowerlimitsoftheparameter,thesymboloftheparametershallbeusedwithoutthe“max.”index.

Themax.-rule

•Forrequirementsspecifiedbythemaximumvalueoftheparameterduringinspection,noneofthemeasuredvaluesoftheparameterovertheentiresurfaceunderinspectionshallexceedthevaluespecifiedonthedrawingsorinthetechnicalproductdocumentation.

•Todesignatethemaximumpermissiblevalueoftheparameter,the“max.”indexhastobeaddedtothesymboloftheparameter（forexampleRz1max.）.

Positionofcomplementarysurfacetexturerequirements

•ThemandatorypositionsofthevarioussurfacetexturerequirementsinthecompletegraphicalsymbolareshowninFigure4-5.

•Thecomplementarysurfacetexturerequirementsintheformof

—surfacetextureparameters,

—numericalvalues,and

—transmissionband/samplinglength,

shallbelocatedatthespecificpositionsinthecompletegraphicalsymbolinaccordancewiththefollowing.

a）Positiona—Singlesurfacetexturerequirement

Indicatethesurfacetextureparameterdesignation,thenumericallimitvalueandthetransmissionband/samplinglength.Toavoidmisinterpretation,adoublespace（doubleblank）shallbeinsertedbetweentheparameterdesignationandthelimitvalue.

Generally,thetransmissionbandorsamplinglengthshallbeindicatedfollowedbyanobliquestroke（/）,followedbythesurfacetextureparameterdesignation,followedbyitsnumericalvalueusingonetextstring.

Example1

0.0025-0.8/Rz6.8（examplewithtransmissionbandindicated）

Example2

-0.8/Rz6.8（examplewithonlysamplinglengthindicated）

Especiallyforthemotifmethod,thetransmissionbandshallbeindicated,followedbyanobliquestroke（/）,followedbythevalueoftheevaluationlength,followedbyanotherobliquestroke,followedbythesurfacetextureparameterdesignation,followedbyitsnumericalvalue.

b）Positionaandb—Twoormoresurfacetexturerequirements

Indicatethefirstsurfacetexturerequirementatposition“a”asina）.Indicatethesecondsurfacetexturerequirementatposition“b”.Ifathirdrequirementormoreistobeindicated,thegraphicalsymbolistobeenlargedaccordinglyintheverticaldirection,tomakeroomformorelines.Theposition“a”and“b”aretobemovedupwardswhenthesymbolisenlarged.

c）Positionc—Manufacturingmethod

Indicatethemanufacturingmethod,treatment,coatingsorotherrequirementsforthemanufacturingprocessetc.Toproducethesurface,forexample,turned,ground,plated.

Thesurfacetextureparametervalueofanactualsurfaceisstronglyinfluencedbythedetailedformoftheprofilecurve.Aparameterdesignation,parametervalueandtransmissionband—indicatedsolelyasasurfacetexturerequirement—donotthereforenecessarilyresultinanunambiguousfunctionofthesurface.Itisconsequentlynecessaryinalmostallcasestostatethemanufacturingprocess,asthisprocesstosomeextentresultsinaparticulardetailedformoftheprofilecurve.

Theremayalsobeotherreasonsforfindingitappropriatetoindicatetheprocess.

ThemanufacturingprocessofthespecifiedsurfacecanbepresentedastextandaddedtothecompletesymbolasshowninFigures4-6and4-7.

✧Positiond—Surfacelayandorientation

Indicatethesymboloftherequiredsurfacelayandtheorientation,ifany,ofthesurfacelay,forexample,“=”,“X”,“M”.

Thesurfacelayanddirectionofthelayemanatingfromthemanufacturingprocess（e.g.tracesleftbytools）maybeindicatedinthecompletesymbolbyusingthesymbolsshowninTable4-1andillustratedbytheexampleinFigure4-8.Theindicationofsurfacelaybythedefinedsymbols（e.g.theperpendicularitysymbolinFigure4-8）isnotapplicabletotextualindications.

Thedirectionoflayisthedirectionoftheprevailingsurfacepattern,whichisusuallydeterminedbythemanufacturingprocessused.

ThesymbolsinTable4.1indicatethelayanddirectionoflayinrelationtothedrawingplanecontainingthesurfacetexturerequirement.

Table4.1Indicationofsurfacelay

Graphical

symbol

Interpretationandexample

Paralleltoplaneofprojectionofviewinwhichsymbolisused

Perpendiculartoplaneofprojectionofviewinwhichsymbolisused

X

Crossedintwoobliquedirectionsrelativetoplaneofprojectionofviewinwhichs