MeasurementSystemsAnalysis.ppt

MeasurementSystemsAnalysis测量系统分析,WarmupExercise热身练习,Task:Youhave60secondstocountthenumberoftimesthe6thletterofthealphabetappearsattherightparagraph.Areyouready?Go!给你60秒的时间数出右边段落中第六个字母的出现次数.,WarmupExercise,DocumentyouransweronascrapnoteAswereadtheanswers,typethemintoaMinitabdatasheet.RunahistogramontheresultsWhatareyourobservations?,ObservedVariation,Whichprocessisbest?,MeasurementVariation,Whichprocessisbest?,PartVariation,Whichprocessisbest?,+,=,PartVariability(Actualvariability),ProcessA,ProcessB,TotalVariability(Observedvariability),MeasurementVariability,LSL,USL,GoodPartsRejected?,MeasurementUncertainty,WhatIsAnMSA?,Scientificandobjectivemethodofanalyzingthevalidityofameasurementsystem一种科学客观的方法，用于有效的分析测量系统A“tool”whichquantifies:一种工具，它量化：EquipmentVariation设备波动Appraiser(Operator)Variation评估者波动TheTotalVariationofaMeasurementSystem测量系统总的波动MSAisNOTjustCalibration测量系统分析不仅仅是校准,MeasurementSystemAnalysisisoftena“projectwithinaproject”测量系统分析经常是”项目中的项目”,MainSourcesOfVariation,Materials材料Methods方法Machines机器People人员Environment环境Measures测量,Measurementsystemsarethemostneglected测量系统经常被忽视,测量系统：是用来对被测特性定量测量或定性评价的仪器或量具、标准、操作、方法、夹具、软件、人员、环境和假设的集合；用来获得测量结果的整个过程。(MSA手册第三版定义),MeasurementSystemAsAProcess,ComponentsOfMeasurementError,Resolution/Discrimination分辨率Accuracy(biaseffects)准确度（偏离）Linearity线性Stability(consistency)稳定性（一致性）Repeatability(Precision)重复性（精度）Reproducibility(Precision)再现性（精度）,Eachcomponentofmeasurementerrorcancontributetovariation,causingwrongdecisionstobemade测量误差的每一项都可能对变差造成影响而使我们做出错误的决策,CategoriesOfMeasurementErrorWhichAffectLocation影响位置的测量误差,CategoriesOfMeasurementErrorWhichAffectSpread影响分布的测量误差,Repeatability,Reproducibility,Resolution/Discrimination分辨率,ResolutionDefinitions分辨率定义,Resolution/Discrimination分辨率Capabilitytodetectthesmallesttolerablechanges可以侦测最小变化的能力InadequateMeasurementUnits不充分的度量单位Measurementunitstoolargetodetectvariationpresent度量单位过大而不能侦测到变化Guideline:“10BucketRule”1/10原则Incrementsinthemeasurementsystemshouldbeone-tenththeproductspecificationorprocessvariation测量系统必须精确到产品范围或过程变差的1/10,Sameprocessoutputbeingmeasured,Resolution/Discrimination分辨率,Resolution分辨率,OnHoldcomplaintsperhour每小时的投诉ComplaintNumberTransfers50Disputes210Information143Other12Total415,Whatisthecustomersbiggestcomplaint?,OnHoldcomplaintsperhourComplaintNumberTransfers50SetuporMaintenanceDisputes70ServiceReceivedDisputes60BillingAmountDisputes80UpdateAccountInformation115RequestInformation28Other12Total415,Whatisthecustomersbiggestcomplaint?,Resolution,Accuracy/Bias准确性/偏离,Differencebetweentheobservedaveragevalueofmeasurementsandthemastervalue测量平均值与基准值之间的差异,Mastervalueisanaccepted,traceablereferencestandard基准值是公认的标准值,Accuracy/Bias准确性/偏离,x,x,x,x,x,x,x,x,x,Lessaccurate,Moreaccurate,Accuracy/Bias准确性/偏离,Linearity线性,Linearity,FullRangeofGage,ReferenceValue,NoBias,ObservedAverageValue,Bias,Linearity-AttributeExample,Surveyscoring:_SuperOutstanding!10_Outstanding!9_Incredible8_Excellent7_Great6_VeryGood5_Good4_OK3_Fair2_Poor1,Isthisafairscale?,Stability稳定性,Stability稳定性,Measurementsremainconstantandpredictableovertime测量系统随时间保持一致性与可预见性Forbothmeanandstandarddeviation含均值与标准偏差Evaluatedusingcontrolcharts可用控制图来检查,Precision精确性,Precision精确性,2total=2product/process+2repeatability+2reproducibility,AlsoknownasGageR&R,Repeatability重复性,VariationthatoccurswhenrepeatedmeasurementsaremadeofthesameitemunderabsolutelyidenticalconditionsSame:OperatorSet-upUnitsEnvironmentalconditions重复性：同一个人使用同样的设备、同样的仪器在同样的条件下测量同一个样品的差异,Repeatability重复性,Reproducibility再现性,VariationthatoccurswhendifferentoperatorsmakethemeasurementsunderabsolutelyidenticalconditionsSame:Set-upsTestunitsEnvironmentalconditionsLocationsCompanies再现性：不同的人使用同样的仪器，在同样的条件下测量同一个样本之间的差异,Reproducibility再现性,R&R重复性与再现性,TheBigPicture:LinkingThemAllTogether2Total=2R&R+2Processoutput2Total=2Repeat+2Reproducibility+2Processoutput2Total=2Repeat+2Oper+2OperProcessoutput+2Processoutput,MeasurementErrorMatchingExercise,Matchthemeasurementelementtothepicturethatbestdescribesit,Type1GageStudy类型1量具分析,PurposeOfType1GageStudy,Todeterminehowmuchofyourobservedprocessvariationisduetomeasurementsystemvariation.确定观测到的过程变异有多少是由于测量系统本身的变异Tocombinedeffectsofbiasandrepeatabilitybasedonmultiplemeasurementsfromasinglepart.通过对单个产品的多次测量来计算偏倚和重复性的影响Type1GageStudyshouldbedonepriortoconductingothergagerepeatabilityandreproducibilitystudies.Todetermineifcalibrationisneed量具的分析应该在做重复性和再现性之前做,来确定是否量具需要校准。,SampleRule,Onemastersample(knownreferencevalue)取一个已知标准值的标准样品Referencevaluescanbedeterminedinmanyways,dependingonindustrystandardsandcompanyandcustomerexpectations.Someofthebasesforreferencevaluesare:标准值可以通过多种方法获得，根据行业和公司标准及客户的期望。1)averageofrepeatedmeasurementsfrommoreaccuratemeasuringequipment用更准确的测量设备测量多次取平均值2)valuesendorsedbyaprofessionalgroup专业机构认可的值3)valuesagreeduponbytheaffectedparties客户认可的值4)valuesdefinedbylaw法律规定的值Tomeasurethemastersample25timesinsameconditionatleast,recordthemeasurements.在相同条件下重复测量标准样品至少25次，记录每次测量数据,StudyMethod,在此处输入测量数据,在此处输入标准值,在此处输入测量值的公差规格,ExampleofType1GageStudy,1OpentheworksheetSHAFT.MTW.2ChooseStatQualityToolsGageStudyType1GageStudy.3InMeasurementdata,enterDiameter.4InReference,type12.305.5UnderTolerance,chooseUpperspec-lowerspecandtype0.05.ClickOK.,ExampleofType1GageStudy,1）分析结果显示偏倚量是-0.00231，P值等于0说明测量系统的偏倚是统计显著的同样从图上可以看出大部分的测量数据都低于标准值。2）Cg是公差和测量变异进行比较，CgK是公差和测量变异及偏倚量两者进行比较Cg和CgK越大，表示测量系统的变异相对公差来说越小。通常Cg和CgK要求大于1.333）%Var(repeatability)由于Cg来确定，%Var(repeatabilityandbias)由Cgk来确定.%Var值小表示测量值变异相对公差而言小.能力指标1.33相当于%Var15%.,AttributeMeasurementSystemStudies离散型数据测量系统研究,PurposeOfAttributeMSA,Assessstandardsagainstcustomersrequirements对顾客要求的标准进行评定Determineifallappraisersusethesamecriteria确定所有的检验者使用相同的标准Quantifyrepeatabilityandreproducibilityofoperators量化操作者的重复性与再现性Identifyhowwellmeasurementsystemconformstoa“knownmaster”确定测量系统对已知标准的符合程度Discoverareaswhere:发现一些领域：Trainingisneeded需要培训Proceduresarelacking缺少规程Standardsarenotdefined标准定义不清晰,SampleRule,30samplesatleast,3appraisersandtwicetests需要3个测量者，最少30个样本与每个样本2次测试40%45%forpasssamples40%45%的好样本40%45%forfailsamples40%45%的坏样本10%forequivocalsamples(ifpossible)10%的边缘样本Thecriteriaforsamplesshouldbedeterminedinadvance.样本的好坏标准需提前确定下来Makesuretherandomizationforthetest保证样本测试的随机性,AttributeMSA-ExcelMethod,AllowsforR&Ranalysiswithinandbetweenappraisers可以分析评估者之间的R&RTestforeffectivenessagainststandard对标准判断的有效性Limitedtonominaldataattwolevels只能用于两个水平的名义性数据,AttributeMSAExample,OpenfileMSA-Attribute.xls,ScoringExample,100%istargetforallscoresDataStackStackBlocksofColumns(StackallProcessOutputs,Operators,andResponsessothattheyareinonecolumnonly),Note:c8,c9,c10arethecolumnsinwhichtherespectivedataarefoundINOUREXAMPLE.YoumusthaveALLdataSTACKEDinthesecolumns,StackedAndReadyForAnalysis,AnalysisinMinitab,ANOVAmethodispreferredGivesmoreinformation,EnterGageInfoandOptions,USL-LSL=0.50,USL=1.0,LSL=0.6,USL=1.0,LSL=0.5,AddingTolerance(Optional),UpperSpecificationLimit(USL)MinusLowerSpecificationLimit(LSL),Forthisexample:,Two-WayANOVATableWithInteractionSourceDFSSMSFPPart92.058710.22874539.71780.00000Operato