.BoardStressAnalysisxxxxxxECTS.O.Number:TodayECTCustomer:Date:PassPass/FailECTCriteria:OverviewAboardstressanalysiswasperformedontheaboveEverettCharlesTechnologiesshopordernumber.TheboardstressanalysisrepresentsastaticsnapshotofthebasePCBunderfullloadinginthein-circuittestfixture.Actualresultswillvarybecauseoftheeffectsofcomponentstiffening,PCBlayermakeup,customervacuumpressureaswellastheassociateddynamicsthatoccurduringtest.Inputs&OutputTheboardstressanalysisutilizestheoutputsdirectlyfromtheECTCAFsoftware.Topandbottomsideprobeforcesareassumedtobeat2/3travelvalues.PCBAfixturerestraintssuchastopandbottomsidezero-flexmilling,push-fingerandUUTsupportlocationsaswellasanyallowableback-upblocksareallconsidered.Airpressureresultingfromvacuumisassumedtobe12.7poundspersquareinch.Onceallvalueshavebeeninput,astaticanalysisisperformed.Theaccompanyingplotillustratestheresultingdeflection.Alldimensionsareininches.Areasofgreatestupwarddeflection(awayfromtheprobefield)occurinred.Reddoesnotgenerallyindicateaproblemhowever.Thecolorssimplyrepresentareasofvaryingdeflection.InordertopassECTcriteriathemaximumvalueasdisplayedinthetopofthelegendshouldbe0.010inchorless.ConclusionTheoverallmaximumdeflectionpredictedis0.008inch.ThisvalueiswithinECT'sacceptablelimitof0.010inch.Figure1:ResultantPCBFlexFigure2:ECT-CAFLoading&DeviceMapNote–Akeywillgoinheredefiningthesymbolsusedforpushfingersandsupports.FYI–bluearepushfingers,greenaresupports***ECTBoardStressAnalysis***TheBoardStressAnalysis(BSA)provided(asafreefeature)isamathematicalmodelthatpredictsdeflectionsthePCBAwillincurduringTest.EverettCharlesTechnologies(ECT)hasvalidateditsBSAsoftwareusingdirectmeasurementtechniques.ManycriticalfixtureparametersareusedintheBSA,somenotableonesincludeprobeplacement,probeforceandfinger/supportlocations.ThemapofdeflectionprovidedisnotaguaranteethatthePCBAorcomponentsonthePCBAwon’tbedamagedduringTest.Themaprathershowstherelativedeflectionsbaseduponhowthefixturewasoriginally