DFMEA全解（完整版）

1、1設計失效模式及效設計失效模式及效应应分析分析Design Failure Mode & Effect Analysis (DFMEA)2FMEA Definition / FMEA 定义An FMEA can be described as a systemized group of activities intended to: 失效模式及效应分析是一组有系统的行为, 其目的是:(a)Recognize and evaluate the potential failure of a product/process and its effects 辨别与评估产品及其工艺的潜在失效模式

2、, 以及由此产生的效应(b)Identify actions which could eliminate or reduce the chance of the potential failure occurring, and 找出行动方案来避免潜在失效的发生, 或降低其可能性(c)Document the process 将以上过程记录在案3FMEA Flow / FMEA 流程Boundary DiagramInterface MatrixP-DiagramFMEA (with Robustness Linkage)Robustness & Reliability Checklis

3、tDesign Validation Plan (DVP)Qualifies and clarifies the relationships between systemsIdentifies and quantifies the strength of system interactionsIdentifies noise and control factors and error statesSummarizes error states, noise factors, and associate design control4Magna Closures Required FMEA Re

4、lated Documents Boundary Diagram P-Diagram CC / SC / KC Product Characteristic Matrix FMEA Checklist Interface Matrix DFMEA Process Flow Diagram PFMEA DVP&R5A Boundary Diagram Example (U204 Liftgate Latching System)Liftgate Latch AssemblyAjar SwitchBrainplateLock ActuatorPlastic Security ShieldG

5、lass LatchO/S Handle Assembly w/ RodWire HarnessGEMAssembly PlantOwner/OperatorVehicle BodyInner Door TrimWater ShieldDoor Seal System (door effort)Striker AssemblyC-pillar sheet metal with paintFastenersWindow Glass clearanceSheet Metal OuterFCSD (Service)Fasteners6A P-Diagram Example (U204 Liftgat

6、e Latching System)U204 Liftgate Latching SystemSignal Factors1) Door Slam Engergy2) Handle release effort Liftgate3) Handle release travel Liftgate4) Handle release effort Glass5) Handle release travel Glass6) Outside release handle cyclingControl FactorsLatch material selections - Frameplate - Hous

7、ing - Ratchet & PawlRatchet & pawl heat treat: 36-42 HRCComponent finishSpring material selectionIdeal Function Response1) Latch releases2) Latch retains striker fullyError State Response1) Latch no function2) Striker not aligned with latch3) Striker not properly engaged4) Gap issues with tr

8、im5) High/low release effort6) High/low release travel7) Inside/outside release handle not functioningNoise FactorsPiece to piece:1) Handle effort 68.6 N Max2) Handle travel 20 29 mm3) Door panel hole tolerance4) Door dimensional variation5) Release rod6) 4-way locator bodyCustomer Usage:1) Handle c

9、ycle loads / Abuse2) Door slam speedSub-system interaction:1) Inner/outer sheet metal2) Latch assembly3) Outside release handle assy4) Linkage5) Electrical connectorAging / Wear Effect:1) Fatigue2) Creek3) Impact durability4) CorrosionEnvironment:1) Temperature2) Humidity3) Dust4) Vibration5) Ice7An

10、 Interface Matrix Example (Headlamp)InterfaceInterfaceMatrix:Matrix:Example ofHeadLamp-1 -2 -1 -12 -2-1 -2-1 -1 -1 -1-1 -1 -1 -122 -2 -1 -12HeadlampHeadlamp HousingHoodGrill Opening PanelBodyConnectorWiring/Electrical SystemScrew/FastenerScrew/FastenerWiring/Electrical SystemConnectorBodyGrill Openi

11、ng PanelHoodHeadlamp HousingHeadlampPEIMP: Physical touching E: Energy Exchange I: Information Exchange M: Material ExchangeNumbers in each corner represent the above interface types, with value denoting the following:+2: Interaction is necessary for function+1: Interaction is beneficial; but not ab

12、solutely necessary for functionality 0: Interaction does not affect functionality-1: Interaction causes negative effects but does not prevent functionality-2: Interaction must be prevented to achieve functionalityNegative values are analyzed for recommended functions.8DFMEA设计失效模式及效应分析设计失效模式及效应分析Desi

13、gn Potential FMEA is: 设计潜在失效模式及效应分析是:an analytical technique used primarily by Design-Responsible Engineer/Team 由负责设计的工程师/小组采用的分析技术to identify potential failure modes用作辨别潜在失效模式to identify associated cause/mechanisms辨别相关原因/机理to support the design process in reducing the risk of failures支持设计过程, 减少失效风险

14、apply to system, subsystem, and component应用于系统、 子系统及部件9Customer of DFMEA顾客的定义顾客的定义Customer for a Design FMEA顾客的定义 End user 通常是指“最终使用者” Manufacturing/Process-responsible engineer 也可以是更高一层设计司，制造或装配生产工程司10Team Effort 小组的努力小组的努力 Design 设计 Manufacturing 制造 Quality 品质 Material 材料 Reliability 可靠性 Sub-contr

15、actor 分供方11DFMEA 设计失效模式及效应分析设计失效模式及效应分析Design FMEA is LIVING document and should设计FMEA是一份动态的文件 be initiated before or at design concept finalization 在一个设计概念最终形成之时或之前开始 be continually updated在产品开发的各个阶段, 发生更改或获得更多的信息时, 持续予以更新 be fundamentally completed before production drawing release在产品加工图样完工之前全部完成1

16、2DFMEA 设计失效模式及效应分析设计失效模式及效应分析Potential failure modes during production “Need Not” but “May Be” included制造的失效模式“不需”但“也可能”包括DFMEA not rely on process controls to overcome design weaknessDFMEA不依靠过程控制来克服潜在的设计缺憾DFMEA considers technical limits of manufacturingDFMEA考虑制造的限制 Mold drafts 拔模斜度 Assembling spac

17、e 装配空间 Tolerances / capability 公差 / 过程能力13Development of a Design FMEA 设计设计FMEA的开始的开始 First Step of DFMEA: IDENTIFY DESIGN INTEND第一步 : 确定设计意图“Listing of what design is expected to do andwhat is expected not to do”“列出设计期望做什么和不期望做什么?14Development of a Design FMEA设计设计FMEA的开始的开始Source of information 资料来

18、源 QFD 质量功能展开 Product Requirement 产品要求 Manufacturing requirement 生产要求 “Design Intent” “设计意图”15Block Diagram 框图框图DFMEA Recommended tool : Block DiagramDFMEA建议工具 : 框图To understand 明白Housing灯罩input to the block 输入Slip fitfunction of the block 功能Batteries电池plate弹簧Compressive fit压紧装接output form the block

19、输出Snap fit 卡扣连接滑动配合16Page_o f_Component_Design Responsibility_Prepared by_Mode Year(s)/Vehicle(s)_Key Date _FMEA Date (Orig.) _(Rev.)_ItemFunction Potential Failure ModePotential Effect(S) of Failure SevClassPotential Cause(s) Mechanism(s) of FailureOccurCurrentDesign ControlsPreventionCurrentDesign

20、 ControlsDetectionDetecRP.N.Recommen-ded Action(S)Responsibility & Target Completion DateAction ResultsActions TakenSeVOccDetR. P.N.1234567891011121314151616171819202122_ System_ SubsystemPOTENTIAL FAILURE MODE AND EFFECTS ANALYSIS(Design FMEA) FMEA Number_ Core Team_17共_頁, 第_頁_部件 _設計責任_編制人_車型年

21、/ 車輛類型_關鍵日期 _FMEA 日期 (編制) _(修訂)_项目 潜在失效模式潜在失效的后果严重度数(S)级别潜在失效的起因 / 机理频度数现行设计控制预防措施现行设计控制探测措施探测度数(D)风险顺序数RPN建议措施责任和目标完成日期措施结果采取的措施严重度数频度数探测度数R.P.N.1234567891011121314151616171819202122_ 系统_ 子系统POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS(Design FMEA)潜在失效模式及后果分析潜在失效模式及后果分析(设计设计FMEA)FMEA 编号_核心小组_ 功能18De

22、tails of DFMEADFMEA的詳細內容的詳細內容1)FMEA Number FMEA编号 2)System, Subsystem, or Component Name and Number 系统、子系统或零部件的名称及编号Enter the FMEA document number, which may be used for tacking. 填入FMEA文件编号, 以便查询。 Indicate the appropriate level of analysis and enter the name and number of the system, subsystem, or c

23、omponent being analyzed.注明適當的分析級別並填入被分析的系統、子系統或部件的名稱及編號。19Design Objectives:1. Minimum 3000 hours of riding without need for maintenance and 10,000 hours of riding for design life.2. Accommodates maleadults comfortably to the 99.5th percentile3. ectFunction: Ease of usePotential Failure Mode(s):Diff

24、icult to steerDifficult to pedalFunction: Provide reliable transportationPotential Failure Mode(s) :Chain breaks frequentlyTires require frequent maintenanceFunction : Provide comfortable transportationPotential Failure Mode(s)Seating position is not comfortableFunction:Provides stable attachment fo

25、r seat supportPotential Failure Mode(s)Structural failure seat support Excessive deflection of seat supportFunction:Provides pleasing appearancePotential Failure Modes(s)Finish (shine)deterioratesPaint chipsHandle Bar AssemblyRear Wheel Assemble Sprocket AssembleFunction:Provides structural supportP

26、otential Failure Mode(s):Structural failureExcessive deflectionFunction:Provides dimensional control for correct finished frame geometry Potential Failure Mode(s):Length of frame mounting points to longLength frame mounting points too shortFunction:Support frame assembly production methods (welding)

27、Potential Failure Mode(s):Bicycle FrameFront Wheel Assemble Seat AssembleChain AssembleUpper FrameLower front Tube Lower Rear TubeSprocket TubeSystem LevelSubsystem LevelComponent Level20设计目标 :1.骑行至少3000小时无需保养,设计寿命为骑行10000小时。2.适于第99.5百分位成年男子骑用, 舒适便利。3.等等.功能功能:便于使用潜在失效模式潜在失效模式:方向把不好用脚踏板不好用功能功能:提供可靠的交

28、通运输潜在失效模式潜在失效模式:链条经常断开需要经常修理车胎功能功能:提供舒适的交通运输潜在失效模式潜在失效模式:车座位置不舒服功能功能:为座位支撑提供稳定的附属物潜在失效模式潜在失效模式:座位支撑的结构性失效座位支撑的过大变形功能功能:提供好看的外观潜在失效模式潜在失效模式:外观(光亮度)变坏漆皮开裂把手总成后轮总成链轮总成功能功能:提供结构性支撑潜在失效模式潜在失效模式:结构性失效过大变形功能功能:对正确的车架几何外形提供尺寸控制潜在失效模式潜在失效模式:车架安装点的长度过长车架安装点的长度过短功能功能:为车架总成的生产方法(焊接)提供支持潜在失效模式潜在失效模式:自行车车架前轮总成车座总

29、成链条总成上部车架下前车管下后车管链轮管系统等级系统等级子系统等级子系统等级部件等级部件等级21Details of DFMEA3)Design Responsibility设计责任4)Prepared By编制者5)Model Year(s) /Program(s)车型年/项目Enter the OEM, department, and group. Also include the supplier name, if applicable.填入整车厂、部门和小组。 如适用, 还包括供方的名称。Enter the name, telephone number, and company of

30、the engineer responsible for preparing the FMEA.填入负责编制FMEA的工程师的姓名、 电话和所在公司的名称。Enter the intended model year(s)/program(s) that will use and/or be affected by the design being analyzed (if know).填入所分析的设计将要应用和 / 或影响的车型年 / 项目(如已知的话。22Details of DFMEADFMEA的详细内容的详细内容6)Key Date关键日期7)FMEA DateFMEA日期8)Core

31、Team核心小组9)Item/Function 项目 / 功能Enter the initial FMEA due date, which should not exceed the schedule production design release date填入初次FMEA应完成的时间, 该日期不应超过计划的生产设计发布日期。Enter the date the original FMEA was compiled and the latest revision date.填入编制FMEA原始稿的日期及最新修订的日期。List the names of the responsible in

32、dividuals and departments that have the authority to identify and/or perform tasks.列出有权确定和 / 或执行任务的责任部门的名称和个人的姓名。Enter the name and other pertinent information of the item being analyzed.填入被分析项目的名称和其它相关信息。23Details of DFMEADFMEA的详细内容的详细内容10) Potential Failure Mode 潜在失效模式Potential failure mode is def

33、ined as the meaner in which a component fail to meet the intended function.所谓潜在失效模式是指部件、子系统或系统有可能会未达到或不能实现项目 / 功能文件中所描述的预期功能的情况。Potential Failure = Failure could occur but may not necessarily occur潜在失效模式 = 这种失效可能发生, 但不一定发生。24Details of DFMEADFMEA的详细内容的详细内容11) Potential Effect(s) of Failure 潜在失效的后果 T

34、he effect of the failure mode on the function, as perceived by the “CUSTOMER”潜在失效的后果定义为顾客感受到的失效模式对功能的影响。 Describe in terms of what customer might notice or experience 要根据顾客可能发现或经历的情况来描述失效的后果。 State Clearly if has impact on safety or non-compliance to regulation如果失效模式可能影响安全性或对法规的符合性, 要清楚地予以说明。25Detai

35、ls of DFMEADFMEA的详细内容的详细内容Noise噪音Intermittent Operation 不稳定Leaks泄漏Regulatory Non-compliance 不符合法规Inoperative不起作用26Details of DFMEADFMEA的详细内容的详细内容12) Suggested Evaluation Criteria Severity (s)严重度The team should agree on the evaluation criteria and ranking system。小组应对评定准则和分级规则达成一致意见。If a failure mode

36、has more than one effects and each has a different severity, then the highest severity should be used for the failure mode. 如果一个失效模式产生若干个具有不同严重度的潜在失效后果, 则应采用其中最大的严重度。27Suggested DFMEA Severity Evaluation CriteriaEffectCriteria: Severity of Effect RankingHazardous without warningVery high severity ra

37、nking when a potential failure mode affects safe vehicle operation and/or involves noncompliance with government regulation without warning.10Hazardous with warningVery high severity ranking when a potential failure mode affects safe vehicle operation and/or involves noncompliance with government re

38、gulation with warning.9Very High Vehicle/item inoperable (loss primary function).8High Vehicle/item operable but at reduced level of performance. Customer very dissatisfied.7ModerateVehicle/item operable, but Comfort/Convenience item(s) inoperable. Customer dissatisfied.6Low Vehicle/item operable, b

39、ut Comfort/Convenience item(s) operable at a reduced level of performance. Customer somewhat dissatisfied5Very LowFit & Finish/Squeak & Rattle item does not conform. Defect noticed by most customers (greater that 75%)4MinorFit & Finish/Squeak & Rattle item does not Conform. Defect no

40、ticed by 50% of customer.3Very Minor Fit & Finish/Squeak & Rattle item does not conform. Defect noticed by discriminating customers (less that 25%)2NoneNo discernible effect.128推荐的 DFMEA 严重度评价准则后果后果评定准则评定准则 : 后果的严重度后果的严重度严重度严重度无警告的严重危害这是一种非常严重的失效形式,它是在没有任何失效预兆的情况下影响到行车安全或不符合政府的法规。10有警告的严重危害这

41、是一种非常严重的失效形式, 是在俱有失效预兆的前提下所发生的, 影响到行车安全和 / 或不符合政府的法规。9很高车辆 / 项目不能运行(丧失基本的功能)8高车辆 / 项目可运行, 但性能下降, 顾客非常不满意。7中等车辆 / 项目可运行, 但舒适性 / 方便性项目不能运行, 顾客不满意。6低车辆 / 项目可运行, 但舒适性 / 方便性项目的性能下降, 顾客有些不满意。5很低配合和外观 / 尖响和卡嗒响等项目不舒服。 大多数顾客(75%以上)能感觉到有缺憾。4轻微配合和外观/ 尖响和卡嗒响等项目不舒服。 50%的顾客能感觉到有缺憾。3很轻微配合和外观 / 尖响和卡嗒响等项目不舒服。 有辨识能力的

42、顾客(25%以下)能感觉到有缺憾。2无无可辨别的后果。129Details of DFMEA13) Classification级别14) Potential Cause(s) / Mechanism(s) of Failure失效的潜在起因/机理Classify any special product characteristics本档目可用于对那些可能需要附加的设计的产品特殊特性的分级Indication of design weakness, the consequence of which is the failure mode 所谓失效的潜在起因是指设计薄弱部分的迹象, 其结果就是失

43、效模式 30Details of DFMEADFMEA的详细内容的详细内容典型的失效起因可包括但不限于Incorrect Material Specified规定的材料不正确Inadequate Design Life Assumption设计寿命设想不足Insufficient Lubrication Capability润滑能力不足Inadequate Maintenance Instructions维护说明书不分Excessive Heat过热Improper Tolerance Specified 规定的公差不当31Details of DFMEADFMEA的详细内容的详细内容典型的失

44、效机理包括但不限于 Wear磨损 Corrosion 腐蚀 Chemical Oxidation化学氧化32Details of DFMEADFMEA的详细内容的详细内容15. Occurrence频度Likelihood that a specific cause/mechanism will occur during design life ranking from 1 to 10.潜在失效起因 / 机理出现频度的评估分为1到10级。In determine the ranking, questions to be considered :在确定此值时在确定此值时, 需考虑以下问题需考虑以

45、下问题 :What is the service History ? 维修史 / 现场经验如何?Is the component completely new? 部件是否是全新的?Environmental changed? 环境有何变化?Application changed? 用途是否有所变化?Have preventive controls been put in place? 是否采取了预防性控制措施?33Details of DFMEASuggest Evaluation CriteriaOccurrence (O) for DFMEAThe team should agree on

46、 the evaluation criteria and ranking system.Suggested DFMEA Occurrence Evaluation CriteriaProbability of FailurePossible Failure RatesRankingVery High: Persistent failures 100 per thousand vehicles/items 1050 per thousand vehicles/items 9High: Frequent failures20 per thousand vehicles/items810 per t

47、housand vehicles/items7Moderate: Occasional failures5 per thousand vehicles/items62 per thousand vehicles/items51 per thousand vehicles/items4Low: Relatively few failure0.5 per thousand vehicles/items30.1 per thousand vehicles/items2Remote:Failure is unlikely=100个 每1000辆车/项目1050个 每1000辆车/项目920个 每100

48、0辆车/项目810个 每1000辆车/项目75个 每1000辆车/项目62个 每1000辆车/项目51个 每1000辆车/项目40.5个 每1000辆车/项目30.1个 每1000辆车/项目2极低：失效不太可能发生=0.01个 每1000辆车/项目1很高：持续性失效高：经常性失效中等：偶然性失效低：相对很少发生失效35Details of DFMEADFMEA的详细内容的详细内容16) Current Design Control 现行设计控制List the prevention, design validation/ verification activities (DV)列出预防措施,

49、设计确认 / 验证Examples 例子Design review 设计评审Fail/safe design (pressure relief valve) 失效与安全设计(减压阀)Feasibility review可行性评审Prototype test 样件试验Mathematical studies数学研究36Detail of DFMEADFMEA的详细內容的详细內容Shall consider two types of design controls要考虑两种类型的设计控制：Prevention:Prevent the cause/mechanism of 预防：预防： failur

50、e OR the failure mode fromoccurring, or reduce their rate ofoccurrence. 防止失效的起因/机理或失效模式出现，或者降低其出现的几率。37Detail of DFMEADFMEA的详细内容的详细内容Detection:Detect the cause/mechanism of探测：探测： failure OR the failure mode, either byanalytical or physical methods, before the item is released to production. 在项目投产之前，

51、通过分析方法或物理方法，探测出失效的起因/机理或者失效模式。38Detail of DFMEADFMEA的详细内容的详细内容17. Detection (D)探测度 Suggested Evaluation Criteria-Detection(D)推荐的评价准则Detection is the rank associated with the “detection” control 探测度是与设计控制中所列的探测控制相关联的定级数。The team should agree on the evaluation criteria and ranking system.小组应对相互一致的评定准则

52、和定级方法达成一致意见。39Suggested DFMEA Detection Evaluation CriteriaDetectionCriteria: Likelihood of Detection by Design ControlRankingAbsolute UncertaintyDesign Control will not an/or can not detect a potential cause/mechanism and subsequent failure mode; or there is no Design Control10Very RemoteVery remot

53、e chance the Design Control will detect a potential cause/mechanism and subsequent failure mode9RemoteRemote change the Design Control will detect a potential cause/mechanism and subsequent failure mode.8Very LowVery low chance the Design Control will detect a potential cause/mechanism and subsequen

54、t failure mode.7LowLow change the Design Control will detect a potential cause/mechanism and subsequent failure mode.6Moderate Moderate chance the Design Control will detect a potential cause/mechanism and subsequent failure mode5Moderately HighModerately high chance the Design Control will detect a

55、 potential cause/mechanism and subsequent failure mode.4HighHigh change the Design Control will detect a potential cause/mechanism and subsequent failure mode.3Very HighVery high change the Design Control will detect a potential cause/mechanism and subsequent failure mode.2Almost CertainDesign Contr

56、ol will almost certainly detect a potential cause/mechanism and subsequent failure mode.140探测度评定准则：设计控制可能探测出来的可能性探测度定级绝对不肯定设计控制将不能和/或不可能找出潜在的起因/机理及后续的失效模式，或根本没有设计控制10很极少设计控制只有很极少机会能找出潜在的起因/机理及后续的失效模式9极少设计控制只有极少机会能找出潜在的起因/机理及后续的失效模式8很少设计控制有很少机会能找出潜在的起因/机理及后续的失效模式7少设计控制有较少机会能找出潜在的起因/机理及后续的失效模式6中等设计控制有

57、中等机会能找出潜在的起因/机理及后续的失效模式5中上设计控制有中上多机会能找出潜在的起因/机理及后续的失效模式4多设计控制有较多机会能找出潜在的起因/机理及后续的失效模式3很多设计控制有很多机会能找出潜在的起因/机理及后续的失效模式2几乎肯定设计控制几乎肯定能找出潜在的起因/机理及后续的失效模式141Detail of DFMEADFMEA的详细内容的详细内容18. Risk Priority Number (RPN)风险顺序数(RPN)Risk priority number is the product of (S), (O)&(D) ranking.风险顺序数是严重度(S)、频度(O)和探测度(D)的乘积。RPN = (S) x (O) x (D)风险顺序数(RPN) = 严重度 X 发生频度 X检测度Special attention on : 应特别留意1.Ranks 9 or 10 in (S); then 严重度为9或10的情况2. High RPN value 高风险顺序数的情况42Detail of DFMEADFMEA的详细内容的详细内容19.Recommended Action 建议的措施Engineering assessment for preventive/corrective action for “High S