1、1設計失效模式及效設計失效模式及效應應分析分析Design Failure Mode & Effect Analysis (DFMEA)2FMEA Definition / FMEA 定義An FMEA can be described as a systemized group of activities intended to: 失效模式及效應分析是一組有系統的行為, 其目的是:(a)Recognize and evaluate the potential failure of a product/process and its effects 辨別與評估產品及其工藝的潛在失效模式

2、, 以及由此產生的效應(b)Identify actions which could eliminate or reduce the chance of the potential failure occurring, and 找出行動方案來避免潛在失效的發生, 或降低其可能性(c)Document the process 將以上過程記錄在案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設計失效模式及效應分析設計失效模式及效應分析Desi

13、gn Potential FMEA is: 設計潛在失效模式及效應分析是:an analytical technique used primarily by Design-Responsible Engineer/Team 由負責設計的工程師/小組采用的分析技術to identify potential failure modes用作辨別潛在失效模式to identify associated cause/mechanisms辨別相關原因/機理to support the design process in reducing the risk of failures支持設計過程, 減少失效風險

14、apply to system, subsystem, and component應用于系統、 子系統及部件9Customer of DFMEA顧客的定義顧客的定義Customer for a Design FMEA顧客的定義 End user 通常是指“最終使用者” Manufacturing/Process-responsible engineer 也可以是更高一層設計司，制造或裝配生產工程司10Team Effort 小組的努力小組的努力 Design 設計 Manufacturing 制造 Quality 品質 Material 材料 Reliability 可靠性 Sub-contr

15、actor 分供方11DFMEA 設計失效模式及效應分析設計失效模式及效應分析Design FMEA is LIVING document and should設計FMEA是一份動態的文件 be initiated before or at design concept finalization 在一個設計概念最終形成之時或之前開始 be continually updated在產品開發的各個階段, 發生更改或獲得更多的信息時, 持續予以更新 be fundamentally completed before production drawing release在產品加工圖樣完工之前全部完成1

16、2DFMEA 設計失效模式及效應分析設計失效模式及效應分析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不依靠過程控制來克服潛在的設計缺憾DFMEA considers technical limits of manufacturingDFMEA考慮制造的限制 Mold drafts 拔模斜度 Assembling spac

17、e 裝配空間 Tolerances / capability 公差 / 過程能力13Development of a Design FMEA 設計設計FMEA的開始的開始 First Step of DFMEA: IDENTIFY DESIGN INTEND第一步 : 確定設計意圖“Listing of what design is expected to do andwhat is expected not to do”“列出設計期望做什么和不期望做什么?14Development of a Design FMEA設計設計FMEA的開始的開始Source of information 資料來

18、源 QFD 質量功能展開 Product Requirement 產品要求 Manufacturing requirement 生產要求 “Design Intent” “設計意圖”15Block Diagram 框圖框圖DFMEA Recommended tool : Block DiagramDFMEA建議工具 : 框圖To understand 明白Housing燈罩input to the block 輸入Slip fitfunction of the block 功能Batteries電池plate彈簧Compressive fit壓緊裝接output form the block

19、輸出Snap fit 卡扣連接滑動配合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)_項目 潛在失效模式潛在失效的后果嚴重度數(S)級別潛在失效的起因 / 機理頻度數現行設計控制預防措施現行設計控制探測措施探測度數(D)風險順序數RPN建議措施責任和目標完成日期措施結果采取的措施嚴重度數頻度數探測度數R.P.N.1234567891011121314151616171819202122_ 系統_ 子系統POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS(Design FMEA)潛在失效模式及后果分析潛在失效模式及后果分析(設計設計FMEA)FMEA 編號_核心小組_ 功能18De

22、tails of DFMEADFMEA的詳細內容的詳細內容1)FMEA Number FMEA編號 2)System, Subsystem, or Component Name and Number 系統、子系統或零部件的名稱及編號Enter the FMEA document number, which may be used for tacking. 填入FMEA文件編號, 以便查詢。 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設計目標 :1.騎行至少3000小時無需保養,設計壽命為騎行10000小時。2.適于第99.5百分位成年男子騎用, 舒適便利。3.等等.功能功能:便于使用潛在失效模式潛在失效模式:方向把不好用腳踏板不好用功能功能:提供可靠的交

28、通運輸潛在失效模式潛在失效模式:鏈條經常斷開需要經常修理車胎功能功能:提供舒適的交通運輸潛在失效模式潛在失效模式:車座位置不舒服功能功能:為座位支撐提供穩定的附屬物潛在失效模式潛在失效模式:座位支撐的結構性失效座位支撐的過大變形功能功能:提供好看的外觀潛在失效模式潛在失效模式:外觀(光亮度)變壞漆皮開裂把手總成后輪總成鏈輪總成功能功能:提供結構性支撐潛在失效模式潛在失效模式:結構性失效過大變形功能功能:對正確的車架幾何外形提供尺寸控制潛在失效模式潛在失效模式:車架安裝點的長度過長車架安裝點的長度過短功能功能:為車架總成的生產方法(焊接)提供支持潛在失效模式潛在失效模式:自行車車架前輪總成車座總

29、成鏈條總成上部車架下前車管下后車管鏈輪管系統等級系統等級子系統等級子系統等級部件等級部件等級21Details of DFMEA3)Design Responsibility設計責任4)Prepared By編制者5)Model Year(s) /Program(s)車型年/項目Enter the OEM, department, and group. Also include the supplier name, if applicable.填入整車廠、部門和小組。 如適用, 還包括供方的名稱。Enter the name, telephone number, and company of

30、the engineer responsible for preparing the FMEA.填入負責編制FMEA的工程師的姓名、 電話和所在公司的名稱。Enter the intended model year(s)/program(s) that will use and/or be affected by the design being analyzed (if know).填入所分析的設計將要應用和 / 或影響的車型年 / 項目(如已知的話。22Details of DFMEADFMEA的詳細內容的詳細內容6)Key Date關鍵日期7)FMEA DateFMEA日期8)Core

31、Team核心小組9)Item/Function 項目 / 功能Enter the initial FMEA due date, which should not exceed the schedule production design release date填入初次FMEA應完成的時間, 該日期不應超過計劃的生產設計發布日期。Enter the date the original FMEA was compiled and the latest revision date.填入編制FMEA原始稿的日期及最新修訂的日期。List the names of the responsible in

32、dividuals and departments that have the authority to identify and/or perform tasks.列出有權確定和 / 或執行任務的責任部門的名稱和個人的姓名。Enter the name and other pertinent information of the item being analyzed.填入被分析項目的名稱和其它相關信息。23Details of DFMEADFMEA的詳細內容的詳細內容10) Potential Failure Mode 潛在失效模式Potential failure mode is def

33、ined as the meaner in which a component fail to meet the intended function.所謂潛在失效模式是指部件、子系統或系統有可能會未達到或不能實現項目 / 功能文件中所描述的預期功能的情況。Potential Failure = Failure could occur but may not necessarily occur潛在失效模式 = 這種失效可能發生, 但不一定發生。24Details of DFMEADFMEA的詳細內容的詳細內容11) Potential Effect(s) of Failure 潛在失效的后果 T

34、he effect of the failure mode on the function, as perceived by the “CUSTOMER”潛在失效的后果定義為顧客感受到的失效模式對功能的影響。 Describe in terms of what customer might notice or experience 要根據顧客可能發現或經歷的情況來描述失效的后果。 State Clearly if has impact on safety or non-compliance to regulation如果失效模式可能影響安全性或對法規的符合性, 要清楚地予以說明。25Detai

35、ls of DFMEADFMEA的詳細內容的詳細內容Noise噪音Intermittent Operation 不穩定Leaks泄漏Regulatory Non-compliance 不符合法規Inoperative不起作用26Details of DFMEADFMEA的詳細內容的詳細內容12) Suggested Evaluation Criteria Severity (s)嚴重度The team should agree on the evaluation criteria and ranking system。小組應對評定準則和分級規則達成一致意見。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. 如果一個失效模式產生若干個具有不同嚴重度的潛在失效后果, 則應采用其中最大的嚴重度。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推薦的 DFMEA 嚴重度評價準則后果后果評定準則評定準則 : 后果的嚴重度后果的嚴重度嚴重度嚴重度無警告的嚴重危害這是一種非常嚴重的失效形式,它是在沒有任何失效預兆的情況下影響到行車安全或不符合政府的法規。10有警告的嚴重危害這

41、是一種非常嚴重的失效形式, 是在俱有失效預兆的前提下所發生的, 影響到行車安全和 / 或不符合政府的法規。9很高車輛 / 項目不能運行(喪失基本的功能)8高車輛 / 項目可運行, 但性能下降, 顧客非常不滿意。7中等車輛 / 項目可運行, 但舒適性 / 方便性項目不能運行, 顧客不滿意。6低車輛 / 項目可運行, 但舒適性 / 方便性項目的性能下降, 顧客有些不滿意。5很低配合和外觀 / 尖響和卡嗒響等項目不舒服。 大多數顧客(75%以上)能感覺到有缺憾。4輕微配合和外觀/ 尖響和卡嗒響等項目不舒服。 50%的顧客能感覺到有缺憾。3很輕微配合和外觀 / 尖響和卡嗒響等項目不舒服。 有辨識能力的

42、顧客(25%以下)能感覺到有缺憾。2無無可辨別的后果。129Details of DFMEA13) Classification級別14) Potential Cause(s) / Mechanism(s) of Failure失效的潛在起因/機理Classify any special product characteristics本檔目可用于對那些可能需要附加的設計的產品特殊特性的分級Indication of design weakness, the consequence of which is the failure mode 所謂失效的潛在起因是指設計薄弱部分的跡象, 其結果就是失

43、效模式 30Details of DFMEADFMEA的詳細內容的詳細內容典型的失效起因可包括但不限于Incorrect Material Specified規定的材料不正確Inadequate Design Life Assumption設計壽命設想不足Insufficient Lubrication Capability潤滑能力不足Inadequate Maintenance Instructions維護說明書不分Excessive Heat過熱Improper Tolerance Specified 規定的公差不當31Details of DFMEADFMEA的詳細內容的詳細內容典型的失

44、效機理包括但不限于 Wear磨損 Corrosion 腐蝕 Chemical Oxidation化學氧化32Details of DFMEADFMEA的詳細內容的詳細內容15. Occurrence頻度Likelihood that a specific cause/mechanism will occur during design life ranking from 1 to 10.潛在失效起因 / 機理出現頻度的評估分為1到10級。In determine the ranking, questions to be considered :在確定此值時在確定此值時, 需考慮以下問題需考慮以

45、下問題 :What is the service History ? 維修史 / 現場經驗如何?Is the component completely new? 部件是否是全新的?Environmental changed? 環境有何變化?Application changed? 用途是否有所變化?Have preventive controls been put in place? 是否采取了預防性控制措施?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個 每1000輛車/項目1050個 每1000輛車/項目920個 每100

48、0輛車/項目810個 每1000輛車/項目75個 每1000輛車/項目62個 每1000輛車/項目51個 每1000輛車/項目40.5個 每1000輛車/項目30.1個 每1000輛車/項目2極低：失效不太可能發生=0.01個 每1000輛車/項目1很高：持續性失效高：經常性失效中等：偶然性失效低：相對很少發生失效35Details of DFMEADFMEA的詳細內容的詳細內容16) Current Design Control 現行設計控制List the prevention, design validation/ verification activities (DV)列出預防措施,

49、設計確認 / 驗證Examples 例子Design review 設計評審Fail/safe design (pressure relief valve) 失效與安全設計(減壓閥)Feasibility review可行性評審Prototype test 樣件試驗Mathematical studies數學研究36Detail of DFMEADFMEA的詳細內容的詳細內容Shall consider two types of design controls要考慮兩種類型的設計控制：Prevention:Prevent the cause/mechanism of 預防：預防： failur

50、e OR the failure mode fromoccurring, or reduce their rate ofoccurrence. 防止失效的起因/機理或失效模式出現，或者降低其出現的幾率。37Detail of DFMEADFMEA的詳細內容的詳細內容Detection:Detect the cause/mechanism of探測：探測： failure OR the failure mode, either byanalytical or physical methods, before the item is released to production. 在項目投產之前，

51、通過分析方法或物理方法，探測出失效的起因/機理或者失效模式。38Detail of DFMEADFMEA的詳細內容的詳細內容17. Detection (D)探測度 Suggested Evaluation Criteria-Detection(D)推薦的評價準則Detection is the rank associated with the “detection” control 探測度是與設計控制中所列的探測控制相關聯的定級數。The team should agree on the evaluation criteria and ranking system.小組應對相互一致的評定準則

52、和定級方法達成一致意見。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探測度評定準則：設計控制可能探測出來的可能性探測度定級絕對不肯定設計控制將不能和/或不可能找出潛在的起因/機理及后續的失效模式，或根本沒有設計控制10很極少設計控制只有很極少機會能找出潛在的起因/機理及后續的失效模式9極少設計控制只有極少機會能找出潛在的起因/機理及后續的失效模式8很少設計控制有很少機會能找出潛在的起因/機理及后續的失效模式7少設計控制有較少機會能找出潛在的起因/機理及后續的失效模式6中等設計控制有

57、中等機會能找出潛在的起因/機理及后續的失效模式5中上設計控制有中上多機會能找出潛在的起因/機理及后續的失效模式4多設計控制有較多機會能找出潛在的起因/機理及后續的失效模式3很多設計控制有很多機會能找出潛在的起因/機理及后續的失效模式2幾乎肯定設計控制幾乎肯定能找出潛在的起因/機理及后續的失效模式141Detail of DFMEADFMEA的詳細內容的詳細內容18. Risk Priority Number (RPN)風險順序數(RPN)Risk priority number is the product of (S), (O)&(D) ranking.風險順序數是嚴重度(S)、頻度(O)和探測度(D)的乘積。RPN = (S) x (O) x (D)風險順序數(RPN) = 嚴重度 X 發生頻度 X檢測度Special attention on : 應特別留意1.Ranks 9 or 10 in (S); then 嚴重度為9或10的情況2. High RPN value 高風險順序數的情況42Detail of DFMEADFMEA的詳細內容的詳細內容19.Recommended Action 建議的措施Engineering assessment for preventive/corrective action for “High S