DFMEA-失效模式與后果分析

1、DFMEA-失效模式與后果分析(Design Failure Mode &Effect Analysis)Marian(Shenzhen)Co.,Ltd編制 ： 曹喜元 Formation By： Jack Cao 日期： Date： 1-Feb-2013主要內(nèi)容容Main content1.DFMEA介紹4.DFMEA關(guān)鍵參數(shù)數(shù)DFMEAPresentationDFMEA KeyParameter2.DFMEA職責5.DFMEA表單填寫寫說明DFMEAResponsibilityDFMEAFormFilling Explanation3.DFMEA制作流程程6.DFMEA案例DFMEAMak

2、e ProcessDFMEAExample一、DFMEA的介紹DFMEAPresentationDFMEA是FMEA中的一種種，F(xiàn)MEA分為：DFMEA和PFMEADFMEAisintheFMEAone type, FMEAContain:DFMEA&PFMEADFMEA是由負責責設計的的工程師師或小組組，在產(chǎn)產(chǎn)品設計計階段盡盡可能的的范圍內(nèi)內(nèi)預估產(chǎn)產(chǎn)品在設設計上可可能發(fā)生生的缺點點.DFMEAisEngineeror group to responsiblescheme,Asfaraspossiblewithin thescopeoftheestimatedproductdesignonth

3、e possiblefaultsintheproductdesignstage.PFMEA是由負責責制造裝裝配的工工程師或或小組，預估產(chǎn)產(chǎn)品在生生產(chǎn)過程程階段或或之前可可能會發(fā)發(fā)生的缺缺點.PFMEAisPEorgrouptoresponsiblescheme, As faraspossiblethe estimatedproductpossiblefaultsinthe productiveprocessorbefore.本章節(jié)重重點講述述DFMEAThis chapterfocusesonDFMEA.DFMEA的形成DFMEAFormationDFMEA是由負責責設計的的工程師師或小組組，

4、在盡盡可能的的范圍內(nèi)內(nèi)預估產(chǎn)產(chǎn)品在設設計上可可能發(fā)生生的缺點點，衡量量該項缺缺點或可可能造成成的影響響，并擬擬定為防防止或檢檢測該缺缺點應改改善的設設計控制制，并推推動其標標準化作作業(yè)，且且必須配配合設計計發(fā)展之之程序反反復執(zhí)行行.DFMEAisEngineeror group to responsiblescheme, As faraspossiblewithinthe scope oftheestimated productdesign on thepossiblefaultsinthe productdesignstage,Measurethefaults or cancauseinfl

5、uence, andplan to preventortestingthedefect shouldbeimproveddesigncontrol,and promotethe standardizedoperation, andmust fitinwith thedevelopmentofdesignprogramandimplementation.最終成品品及其所所有相關(guān)關(guān)的系統(tǒng)統(tǒng)、子系系統(tǒng)都應應納入評評估.DFMEA是設計小小組，即即公司工工程，運運用設計計，工程程經(jīng)驗或或分析方方法等而而形成的的.Thefinaland allrelated system,subsystem shoul

6、dbeincludedinassessment.DFMEAisthedesign team, namelythecompanyproject,theuse of design,engineeringexperienceoranalysismethods andform.DFMEA必備條件件DFMEAEssentialCondition確認已知知及潛在在的失效效模式；Confirm theknownandthe potentialfailuremode.確認每一一個失效效模式的的效應和和原因；Confirm eachfailuremode effectandreasons.風險優(yōu)先先評估（嚴重性

7、性、發(fā)生生頻率、難檢度度）；Risk priority evaluation(severity,occurrencefrequencyanddifficult tocheckdegree)提供問題題的數(shù)據(jù)據(jù)及改善善行動；Provide problemofdataandimprovementaction.DFMEA的動態(tài)鏈鏈DFMEATrendsCatenationDFMEA是個循環(huán)環(huán)過程，在設計計方案最最終形成成之時或或之前開開始.DFMEAisa cyclicprocess,thedesign schemeoffinalform or beforethestart.在產(chǎn)品開開發(fā)各階階段中，當

8、設計計有變化化或得到到其他信信息時，應及時時，不斷斷地修改改，最終終在產(chǎn)品品加工圖圖樣完成成之前全全部結(jié)束束。Ineverystageofproduct development,when thedesignchange or getotherinformation,should be prompt,constantlymodified,finally,inproductprocessing patternuntilall over.二、DFEMA職責DFMEAResponsibility工程經(jīng)理理：DFMEA總體負責責人，負負責組建建DFMEA團體，提提出DFMEA實施計劃劃，并組組織召開開D

9、FMEA會議，分分配團隊隊人員任任務組織DFMEA評審，DFMEA審核.Project manager: generalmanager,responsiblefor DFMEA,thispaperputs forwardaDFMEAgroupDFMEAimplementationplan,andorganizea DFMEA meeting,distributionteam personneltaskOrganizationDFMEAreview, DFMEA audit.工程師：負責主主導DFMEA文件編寫寫、修改改和升級級.Engineer:responsiblefor leadingDF

10、MEAdocumentpreparation,modificationandupgrade.二、DFEMA職責DFMEAResponsibility工程助理理：負責責客戶投投訴問題題，研發(fā)發(fā)、試產(chǎn)產(chǎn)、量產(chǎn)產(chǎn)中問題題 的收收集，及及時反饋到到DFMEA團體負責責人處，并參與與O,S,D參數(shù)評估估，提供供量產(chǎn)CPK數(shù)據(jù).Project assistant:responsiblefor customer complaintproblem,researchandtrialproduction,thequantityofcollection,andrenderWhenthefeedbacktoDFMEA

11、groupplace,and participate in O,S,Dparameterevaluation,Supplyvolume productionCPKdata.試樣工程程師：負負責研發(fā)發(fā)產(chǎn)品測測試過程程 中所所出現(xiàn)問問題點的的收集并并及時反饋到DFMEA負責人處處，參與與O,S,D參數(shù)評估估.Sampleengineer: responsible forresearchanddevelopmentintheprocessofproduct testingproblemspointcollectionandtimelyfeedbacktotheDFMEAchiefplace, par

12、ticipate in O, S, Dparameter evaluation.二、DFEMA職責DFMEAResponsibilityCQE：負責客客戶需求求信息歸歸納整理理，DFMEA建議措施施監(jiān)督實實施、追追蹤，實施施效果反反饋，根根據(jù)DFMEA和客戶需需求等信信息制定定控制計計劃，并參與O,S,D參數(shù)評估估.CQE:Beresponsibleforthe customer demandinformationsummary,DFMEAsuggestedmeasuressupervisionand implementation,trackingandeffectfeedback, acco

13、rdingtotheDFMEAandrequirementsfor informationsuch as controlplan,and participate inO, S, Dparameterevaluation.三、DFMEA制作流程程DFMEAMake process注：團隊隊制定目目標，使使團隊清清楚新產(chǎn)產(chǎn)品或以以改善為為目標，并并需要了了解客戶戶需求。Note:Theteam setgoals,maketheteamclearnewproductsortoimprove as thegoal,andneed to understandcustomerneeds.使用方法法；Met

14、hodofapplication.客戶要求求的設計計/工程SPEC；Customerrequestedproject&EngineeringSPEC.產(chǎn)品信賴賴；ProductTrust.制程、生生產(chǎn)、裝裝配要要求；Process,ProductionAssembleofRequirement.品質(zhì)目標標. QualityDestination.組成DFMEA團隊Constitute DFMEA Team確定目標標Confirm Destination三、DFMEA制作流程程DFMEAMake process產(chǎn)品設計計及類似似產(chǎn)品設設計的問問題及原原因；Productdesignand sim

15、ilarproductdesignproblemsand reasons制造工藝藝及類似似產(chǎn)品制制程中常常及的不不良原因因；Manufacturingprocess andsimilarproductsinprocess andbadreason.類似產(chǎn)品品的制程程能力及及原因；Similar products of processcapabilityandthereason.類似產(chǎn)品品的客訴訴及原因因；Similarproductsofcustomercomplaintand thereason.類似產(chǎn)品品的依賴賴性失效效及原因因；Similarproductsthedependenceof

16、thefailureandthereason.類似產(chǎn)品品的管理理性問題題；Similarproductsofmanagerialproblems.資料收集集Data Collection三、DFMEA制作流程程DFMEAMake process使用維修修；UseMaintain.環(huán)境.Environment.表格格式式TableFormat.分層層次次DelaminationAdministrative levels.失效定義義FailureDefinition.成果整合合AchievementIntegration.時機Opportunity.資料收集集Data Collection制訂執(zhí)行

17、行方案Formulateimplement Plan三、DFMEA制作流程程DFMEAMake process分析制程程特性AnalysisProcess Character定義制造造流程Definition productionProcess分析產(chǎn)品品特性AnalysisProduct Character分析失效效原因AnalysisFailure Cause分析現(xiàn)行行控制方方法AnalysisControl Method分析失效效效應AnalysisFailure Effect分析發(fā)生生率AnalysisOccurrence Rate分析難檢檢度AnalysisDetection分析嚴重重

18、度AnalysisSeverity計算風險險優(yōu)先數(shù)數(shù)Calculated RiskPriorityNumber分析制程程特性AnalysisProcess Character三、DFMEA制作流程程DFMEAMake process決定優(yōu)先先改善的的失效模模式DecideAmeliorativeFailure Mode建議改善善措施RecommendationImprovementMeasures改善實施施ImprovementImplement結(jié)果確認認有效ResultNotarizeEffective四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度、發(fā)生率率、難檢檢度、風風

19、險優(yōu)生生數(shù)Severity,Occurrence,Detection,RPN嚴重度Severity-S發(fā)生率Occurrence-O難檢度Detection-D風險優(yōu)生生數(shù)Risk Priority Number-RPNRPN=S*O*D四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度Severity衡量失效的的影響程程度.Assessment failureincidence失效影響響產(chǎn)品或或制程，某一失失效會對對產(chǎn)品外外觀、結(jié)結(jié)構(gòu)、功功能、性能穩(wěn)定定性、可可靠性的的影響；或?qū)ο孪乱粋€制制程，使使用者和和設備的影響響；或?qū)ψ罱K客客戶，政政府法規(guī)規(guī)、安全全、環(huán)保保等的違違及.

20、Failure affectproduct or process, afailuretoproduct appearance, structure,function, performance stabilityandreliabilityofthe influence;Ortothe nextprocess,the userand theinfluenceofthe equipment;Ortoend customers,governmentregulations,safety,andenvironmentalprotection,andadefault.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKe

21、yParameter嚴重度Severity嚴重度的的劃分標標準-主觀判定定SeverityClassificationStandard-Subjectivity Decide其大小由由失效模模式的影影響程度度而定，以1至10表示等級級.Itssize of thefailure modeofthe influencedegreetodecide,be1 to 10showlevel.1級最輕微微，10級最嚴重重.1Levelbestslight, 10 Levelbestgrave.1級-幾乎不會會有什么么影響.1Level-Almosthasnoinfluence.10級-違反安全全和法規(guī)規(guī)

22、.10Level-Violationofsafetyandregulations.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度分分類SeverityClassify耐火性、自然性性、UL、RHoS&HFFire Resistance, Naturalness,UL,RHoS&HF一、危危險特性性Catastrophic工業(yè)標準準(無法滿足足而不能能銷售）IndustryStandardIncapableCon notMarket.客戶要求求CustomerRequest內(nèi)部工程程需要由由Critical測量項目目InternalENG needfor critical me

23、asureproject四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度分分類SeverityClassify客戶及供供應商共共同制定定特性；CustomerandSuppliertogetherformulate features.二、 重大大特性Significant或客戶指指定特性性，如導導電或絕絕緣；(滿足而不不能銷售售給指定定客戶)Orcustomerappoint features,ForinstanceEC&Insulation.Content ConnotMarket設計工程程指定的的特性；DesignationCustomerDEappoint feature

24、s.行業(yè)標準準.Industrial standard.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度分分類SeverityClassify可靠性測測試，如如拉拔力力測試；.ReliabilityTesting,Forexampledrawingforcetest .三、 主要要特性Major產(chǎn)品制程程不良率率及分析析Product processreject ratio andanalysis.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度等等級標準準SeverityRank Standard等級/評分Rank劃分標準Divide Standard1幾乎無

25、影響Almost no influence2產(chǎn)品在客戶使用組裝過程中，組裝性差，客戶一般難已發(fā)現(xiàn)，關(guān)注的問題.Products in the customers to use assembly process, assembly sex difference, the customer general difficult has found, pay attention to the problem.3產(chǎn)品之中主要應用的功能稍有瑕疵，如絕緣等，非專業(yè)人員無法識別，EMC II級要求.The product is mainly used in the function of the slight

26、ly defects, such as insulation, laypeople cant identify, EMC level II requirements.4在高于產(chǎn)品承諾的環(huán)境中使用失效，但此環(huán)境低于公司內(nèi)部控制標準或者已達到行業(yè)協(xié)會標準要求，EMC I級要求.不符合標準化的定義.In the above product promised environment with failure, but the environment is lower than the internal control standards or has reached industry associat

27、ion standard requirements, EMC I level requirement. Do not conform to the standard definition.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度等等級標準準SeverityRank Standard等級/評分Rank劃分標準Divide Standard5存在的問題使產(chǎn)品長期運行的可靠性能降低，如產(chǎn)品粘力、導電產(chǎn)品的導電性能等，產(chǎn)品結(jié)構(gòu)復雜，甚至需要培訓才能完成或當前的技術(shù)無法解決的功能性問題 .Problems make the product long-term operation

28、of the lower reliability, such as product viscous force, conductive products of conductive performance and so on, the product structure is complex, even need training to complete or current technology cannot solve the problem of functional.6產(chǎn)品維護復雜，裝配、生產(chǎn)非常困難；設計的產(chǎn)品公司工藝無法完成；客戶獨特配件的兼容性問題 ；不能95以%以上機率復現(xiàn)的問

29、題；計算機監(jiān)測功能失效或誤差大.Product maintenance, assembly, production is very difficult; Design products company process was unable to complete; Customer unique accessories compatibility problem; Cant 95 to % above probability reproduction; Computer monitoring function failure or big error.7客戶關(guān)注的重點功能性問題或者是產(chǎn)品主推場

30、所應用的兼容性問題；產(chǎn)品量化參數(shù)不達標.Customer focus of concern functional problems or is the product of the main place the application compatibility problem; Product quantitative parameters not standard.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter嚴重度等等級標準準SeverityRank Standard等級/評分Rank劃分標準Divide Standard8基本功能失效，失效影響計算機數(shù)據(jù)處理功能.The b

31、asic function failure and influence the computer data processing function.9影響產(chǎn)品安全運行或者包含不符合法律、法規(guī)；產(chǎn)品執(zhí)行標準影響人身安全；產(chǎn)品失效時有警告.Influence the safe operation of the product or contain does not comply with the laws, rules and regulations. Product standards affect personal safety; Product failure is warning.10影響

32、產(chǎn)品安全運行或者包含不符合法律、法規(guī)；產(chǎn)品執(zhí)行標準影響人身安全；產(chǎn)品失效時無警告.Influence the safe operation of the product or contain does not comply with the laws, rules and regulations. Product standards affect personal safety; Product failure isnt warning.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter發(fā)生率Occurrence某一原因因而導致致失效發(fā)發(fā)生的幾幾率.A reasontotheoddso

33、ffailure.劃分標準準：依據(jù)據(jù)不良品品出現(xiàn)的的機率來來定，以以1至10表示等級級.Thedivisionstandard: accordingtotheprobabilityofbad productappearedtodecide, be1 to 10showlevel.1級最輕微微，10級最嚴重重.1Levelbestslight, 10 Levelbestgrave.1級-幾乎不會會發(fā)生.1Level- Almostwonthappen.10級-肯定會發(fā)發(fā)生.10Level-Will happen四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter發(fā)生率Occurrence劃

34、分標準準-CPK、主觀判判定、統(tǒng)統(tǒng)計資料料DivideStandard-CPK, Subjectivejudge, statisticalinformation劃分標準 Divide Standard等級/評分Rank描述Describe發(fā)生率OccurrenceCPK1(Remote)幾乎不可能發(fā)生Almost wont happen.1/1500K1.672(Very Low)有輕度發(fā)生的可能With mild possible1/150K1.503(Low)有可能發(fā)生possible1/15K1.334(Moderate)偶爾發(fā)生，但不占有大的比例Occasionally occur,

35、but dont have great proportion1/2K1.175(Moderate)1/400PCS1.006(Moderate)1/80PCS0.83四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter發(fā)生率Occurrence劃分標準準-CPK、主觀判判定、統(tǒng)統(tǒng)計資料料DivideStandard-CPK, Subjectivejudge, statisticalinformation劃分標準 Divide Standard等級/評分Rank描述Describe發(fā)生率OccurrenceCPK7(High)經(jīng)常發(fā)生Often occur1/20PCS0.678(High

36、)1/8PCS0.519(Very high)幾乎不可避勉Almost do not avoid layer1/3PCS0.3310(Very high)1/2PCS0.33四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter難檢度Detection在現(xiàn)行的的控制措措施下，偵測失失效發(fā)生生的能力力.Inthecurrentcontrol measures,theabilitytodetectfailurehappened.劃分標準準：依據(jù)據(jù)失效模模式檢驗驗的難易易程度來來定，以以1至10表示等級級.Thedivisionstandard: Accordingtothefailuremod

37、e of thetestdifficultytoset,be1 to 10showlevel.1級最容易易，10級為幾乎乎不可能能發(fā)現(xiàn).1Levelbesteasy,10LevelforAlmostimpossibilityfind.1級-用有效的的手段完完全可以以檢測出出來1Level-Witheffectivemeanscompletelycanbedetected.10級-無任何手手段可以以檢測出出來.10Level-Nomeanscan be detected.四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter難檢度Detection劃分標準準-主觀判定定、統(tǒng)計計資料Divid

38、eStandard-Subjectivejudge,statisticalinformation劃分標準 Divide Standard等級/評分Rank描述Describe可偵度Detection12幾乎可以肯定地檢測出來Almost certainly detected99.99%35有良好的手段可以檢測出來Have good means can be detected99.80%68可能能檢測出來Might be able to test out98.00%9有可能檢測不出May cannot be detected90.00%10很有可能檢測不出來Very likely test do

39、es not come out90.00%四、DFMEA關(guān)鍵參數(shù)數(shù)DFMEAKeyParameter風險系數(shù)數(shù)Risk Priority NumberRPN=S*O*D風險系數(shù)數(shù)RPN排出次序序后，RPN越大越優(yōu)優(yōu)先解決決.RPN在100以上必須須解決；50RPN100應盡可能能解決，不能解解決必須須加嚴控控制；RPN50可不加控制.當嚴重度度(S)很高或發(fā)發(fā)生率(O)很高時，不管RPN大小如何何，都必必制定相應應改善或或控制措措施，并并指定責責任人和和改善完完成日期期.Risk coefficient RPNdischargeorder, thebiggerthe RPNpriority.R

40、PN in morethan100mustbesolved;50RPN100should as faraspossibletosolve,cantsolvemustbetightenedcontrol;RPN 50dontaddcontrol.Whentheseverity(S) or highincidence (O)isvery high, no matterhowRPN sizewillbeformulatethe correspondingimprovementorcontrolmeasures,and appointresponsiblepersonsandimprovethecom

41、pletiondate.如何制定定改善措措施Howtomaketheimprovementmeasures針對預防防/糾正措施，以降低低評價等等級的內(nèi)內(nèi)容順序序為：嚴嚴重度、發(fā)生率率及偵測度度；Aimingatpreventing/corrective measures,inordertoreducethe contentofthe evaluationgradeorder:(S), (O),(D).通過設計計變更來來消除或或控制一一個或多多個失效效模式的的起因機機理，能能降低嚴嚴重度等級級；Throughthedesign changetoeliminateorcontroloneormor

42、eofthecauseofthe failuremodemechanism, canreducethe severity level;透過設計計變更，去除或或管制某某一或多多個影響響失效模模式的原原因或設設備，只只能降低發(fā)發(fā)生率的的等級.Throughthechange of thedesign, removeorcontrol oneormore of thecauseofthefailuremode effectorequipment, canreducethe incidenceofgrade.增加設計計驗證，修改測測試計劃劃，修改改原物料料規(guī)格，只可降降低難檢檢度.Toincrease

43、thedesign verification,modifying thetest plan, modifytheoriginalmaterialspecifications, canonly reducethedifficult degreeoftest.五、DFMEA表單填寫寫說明1DFMEANotesoncompleting theform(1)DFMEA編號：填填入DFMEA文件的編編號，以以便要詢詢；DFMEANumbers:fill in theDFMEAfile Numbers, so thattoinformation;項目：填填入所分分析的系系統(tǒng)、子子系統(tǒng)或或零件的的過程名名稱

44、，編編號；Project:fill in theanalysisofthesystem,subsystemorpartsofthe processname,Numbers;設計責任任：部門門、小組組還應包包括供方方的名稱稱；Designresponsibility: department, theteam alsoshould includethe nameofthesupplier;填入負責責DFMEA工作的工工程師姓姓名、電電話及所所在公司司名稱；Fill in theresponsibleoftheengineers DFMEA name, phone numberandthename

45、of thecompany;填入將使使用或正正被分析析的設計計過程影影響的預預期的機機型和料料號；Fill in willuse or arebeinganalyzedtheinfluence of thedesignprocessoftheexpectedtypeandmaterialnumber;關(guān)鍵日期期：填入入DFMEA初次預定定完成日日期，該該日期不不應超過過計劃開開始設計計生產(chǎn)發(fā)發(fā)布日期期.Thekey date: fillinthe DFMEA first targetcompletion date, thisdateshallnotexceed thedesignplantob

46、eginproduction releasedate.五、DFMEA表單填寫寫說明2DFMEANotesoncompleting theform(2)DFMEA日期：填填入編制制DFMEA原始稿的的日期及及最新修修訂日期期；DFMEAdate:fillinthedrawupDFMEAdate andlatestrevisiondate.核心小組：列出有有權(quán)確定定和執(zhí)行行任務的的責任部部門和個個人姓名名，如果果對某一一特定原原因無建建議措施施，那么么就在該欄欄中寫“N/A”.Thecoreteam:list shall havethe right to determineandimplement

47、 theresponsibilityofthedepartmentandindividualtask name, if forA particularreason no suggestedmeasures,thenwriteinthecolumnofN/A.項目/功能：填填入被分分析項目目的名稱稱和編號號，若該該項目有有多種功功能，且且有不同同的失效效模式，應把所所有功都單獨列列出.Project/function: fillinthe nameofthe projectare analyzed andNumbers,iftheprojecthasavarietyoffunctions, an

48、dhave differentfailure mode, we shouldputall functionsarelisted separately.潛在失效效模式：對一個個特定項項目及其其功能，應用規(guī)規(guī)范化，專業(yè)性性的術(shù)語語來列出出每一個個潛在的的失效模模式前提是這這種失效效可能發(fā)發(fā)生，但但不一定定發(fā)生.Potentialfailuremode:foraspecificproject anditsfunction, theapplicationofstandardized,professionaltermstolist eachpotential failuremodeprovidedtha

49、t failuremay occur,butdoesnotnecessarilyoccur.五、DFMEA表單填寫寫說明3DFMEANotesoncompleting theform(3)潛在失效效后果，就是失失效模式式對系統(tǒng)統(tǒng)功能的的影響，一般是是客戶在在使用時時看到的的狀況；Potentialfailure consequences,isthe failuremodeoftheinfluence of thesystemfunction, it is toseethecustomers in theuseofthesituation.嚴重度(S)Severity分級（重重要程序序）用于于對零件件、系統(tǒng)統(tǒng)、子系系統(tǒng)的產(chǎn)產(chǎn)品特性性分級：關(guān)鍵、主要、重要、輕微等等.Cla