FMEASMTWord下载.docx

FMEASMTWord下载.docx

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N

RPN

Screenprintsolderpaste

Solderbridge

Visualinspectionreject

5

Stencilapertureopeningtoobig

3

Visualforsolderbridging

3

45

Reductionontheapertureopening.

RefertolatestDGdesign.

Buyoffstencilbeforeuse.

Metalmasktensionloose

Visualforsoldersmearing

Developmeasuringmethod&

frequencytoensurestencilisingoodcondition

Squeegeebladewornout

Visualforsoldersmearing

Changesqueegeebladeafter10,000prints

Squeegeedownstopandpressuretominimumsetting–justenoughtohaveacleansweep

Cont.

Nosolder

ICTtestdetectedfailed

Stencilopeningclogged

6

Visualformissingprint

90

Re-softensolderpasteonstencileveryhourly.

Timesetting:

1minutes

Useautomaticsolder

pastesoftenermachine

InsufficientSolderpasteonthestencil

Maintainsatleast10mm“hotdog”rollingeffect

Insufficientsolder

8

Squeegeepressuretoohigh

LSMthicknessmeasurement

144

Chipshooting

Misalignment>

25%

VisualInspection

SkippedPCBfiducial

3XVisualinspectionformisalignment

SMTEngineeringtoensureplacementprogrammedwithPCBfiducialmarkson.

IndividualX-Yteaching

SMTEngineeringtouseoriginalCADdataforNCprogram.Individualteachingisnotallowed.

Onlypatternoffsetisallowed.

Missingcomponent

Visual

Vacuumsensordirty

Visualinspection

Weeklymaintenance

fornozzle#1

ICPlacement

25%QFP

Skippedlocalfiducial

3XVisualinspection

75

SMTEngineeringtoensureall20milQFPplacementsprogrammedwithlocalfiducialmarks.

QFPSolderbridge

Pressedtoohardwhenplacing

3XVisualinspection

5

Alterplacementheightuntilnodepression.

Setprevacuumcheckto1

Hotairreflow

Component

thermalshock

ICT/FTtestdetectedfailed

8

Causedbyhighpre-heatramprate

Defectivecomponent

72

Maintainspre-heatrampratebelow3º

C/sec

Mid-chipsolderballs

Causedbyhighpre-heatramprate

Visualinspectionforsolderballs

Maintains60secminimumfor100º

Cto150º

C

PoorWetting

ICT/FTtestdetectedfailed

Causedbyinsufficientheatappliedtothejoints

Opencircuit

Thermalprofilingshalltagtothecoolestpointoftheboard/component

Maxpeaktemp235º

C

at215º

C>

15sec

3.0Severity（R）

Severityisanassessmentoftheseriousnessoftheeffectofthepotentialfailuremodetothecustomer.Severityappliestotheeffectonly.Ifthecustomeraffectedbyafailuremodeistheassemblyplantortheproductuser,assessingtheseveritymaylieoutsidetheimmediateprocessengineer’steamfieldofexperienceorknowledge.Inthesecases,thedesignFMEAdesignengineer,andorsubsequentmanufacturingorassemblyplantprocessengineershouldbeconsulted.Severityshouldbeona“1”to“10”scale.

Effect

Criteria:

SeverityofEffect

Ranking

Remarks

Hazardouswithoutwarning

Mayendangermachineorassemblyoperator.Failurewilloccurwithoutwarning

10

Hazardouswithwarning

Mayendangermachineorassemblyoperator.Failurewilloccurwithwarning

9

Veryhigh

Majordisruptiontoproductionline.100%oftheproductmayhavetobescrapped.

High

Minordisruptiontoproductionline.Productmayhavetobesortedandaportion（lessthan100%）

7

Moderate

Minordisruptiontoproductionline.Aportion（lessthan100%）oftheproductmayhavetobescrapped（nosorting）.

Low

Minordisruptiontoproductionline.100%ofproductmayhavetobereworked.Customerexperiencesomedissatisfaction

VeryLow

Minordisruptiontoproductionline.Theproductmayhavetobesortedandaportion（lessthan100%）reworked.Fit&

finish/squeakrattleitemdoesnotconform.Defectnoticedbymostcustomers.

4

Minor

Minordisruptiontoproductionline.Aportion（lessthan100%oftheproductmayhavetobereworkedonlinebutoutofstation.

Veryminor

Minordisruptiontoproduction.Aportion（lessthan100%）oftheproductmayhavetobereworkedonlinebutinstation.

2

None

Noeffect

1

4.0Occurrence（O）

ProbabilityofFailure

Possiblefailurerates

Veryhigh:

Failureisalmostinevitable

1in2

1in3

High:

generallyassociatedwithprocessessimilartopreviousprocesseswhichhaveexperiencedoccasionalfailuresbutnotinmajorproportions

1in8

1in20

Moderate:

Generallyassociatedwithprocessessimilartopreviousprocesseswhichhaveexperiencedoccasionalfailures,butnotinmajorproportions.

1in80

1in400

1in2,000

Low:

Onlyisolatedfailuresassociatedwithalmostidenticalprocesses

1in15,000

VeryLow:

Onlyisolatedfailuresassociatedalmostidenticalprocesses

1in150,000

Remote:

Failureisunlikely.Nofailureseverassociatedwithalmostidenticalprocesses

Lessthan1in1,500,000

5.0Detection（D）

Likelihoodtheexistenceofadefectwillbedetectedbyprocesscontrolbeforeornextsubsequentprocess,orbeforepartofcomponentleavesthemanufacturingorassemblylocation

Almostimpossible

Noknowncontrol（s）availabletodetectfailuremode

Veryremote

Veryremotelikelihoodcurrentcontrol（s）willdetectfailuremode

Remote

Remotelikelihoodcurrentcontrolswilldetectfailuremode

Verylowlikelihoodcurrentcontrolswilldetectfailuremode

Lowlikelihoodcurrentcontrolswilldetectfailuremode

Moderatelikelihoodcurrentcontrolswilldetectfailuremode

Moderatelyhigh

Moderatelyhighlikelihoodcurrentcontrolswilldetectfailuremode

Highlikelihoodcurrentcontrolswilldetectfailuremode

Veryhighlikelihoodcurrentcontrolswilldetectfailuremode

Almostcertain

Currentcontrolsalmostcertaintodetectthefailuremode.Reliabledetectioncontrolsareknownwithsimilarprocesses

Failuremodeandeffectanalysis

1.Introduction

Productsandprocessthatfailtoperformforcustomersareobviouslynotgoingtobeconsideredhighquality.Proactivequalitystrategiesfocusonfailureprevention–virtualeliminationofthepossibilityofprematurefailure–andmistake-proofing,asfaraspossible.Manytoolsexistfortheanalysisofperformancefailure,consequence,andrisk.Thesetoolsareusedinbothproactiveandreactivemodes.Oneofthemostversatiletools,FMEAfocusesonfailuremodes,mechanismsandeffects.Intheproactiveapplication,FMEAcanbeadaptedtofocusonfailureprevention.

FMEAseekstoidentifypossiblefailuremodesandmechanisms,theeffectsorconsequencesthatfailuremodesmayhaveonperformance,methodsofdetectingtheidentifiedfailuremodes,andpossiblemeansforprevention.

ThenetresultsfromeffectiveFMEAworkareproductandprocessactionplansforelimination,oratleastmitigation,ofthefailuremodes.

2.FMEAisabsolutelyessentialinsounddesignpractice,formproductandprocessdefinition,startinginqualityplanningandqualityfunctiondeploymentandcontinuingthroughthedevelopmentstages.FMEAencouragesasystematiccradle-to-graveviewofaproductorprocess.Itiswidelyusedinmaintainability,safety,andsurvivabilityanalysis;

itsbroadbasemakesiteffectiveinbothproductandprocessperformanceimprovement.

Fromasystemdevelopmentperspective,FMEAencourages

a.Thesystematicevaluationofaproductorprocessatspecifiedlevelofsystemcomplexity[thesystem,subsystemandcomponentlevel]

b.Thepostula