【正文】 ey design elements that satisfy the customer requirements 針對客戶的每一個要求列出滿足該要求的關鍵設計要素 ? For each key design element list ways that the design element could vary, Potential Failure Modes 列出每一個關鍵設計要素的變化 ,潛在的失效模式 ? List Effects of each Failure mode on the customer requirement 列出每個失效模式的對客戶要求的影響 ? List Causes for each failure Mode 列出失效模式的原因 37 FMEA General Steps in the DFMEA/一般步驟 ? List current controls for each cause 列出每個原因的現(xiàn)有控制手段 ? Assign Severity, Occurrence, and Detection ratings to each cause 給每個原因的嚴重度 ,頻度 ,可探測度評分 ? Calculate RPNs 計算風險序數(shù) ? Remend actions to reduce high RPNs 提出降低風險序數(shù)的措施 ? Take appropriate action 採取適當?shù)拇胧? ? Recalculate RPNs 重新計算風險序數(shù) 38 FMEA ? A schematic representation, with 一種圖示法 , 其中 – Components (or features) shown as blocks, 用方塊表示各元件 (或特性 ) – Interactions between ponents shown as lines, 用直線表示各元件之間的關係 – At the appropriate level of detail 詳細到恰當?shù)某潭? Develop a Functional Block Diagram of The Product 繪制產(chǎn)品功能結構圖 39 FMEA Component 元件 Component 元件 Component 元件 Component 元件 Component 元件 Component 元件 Block Diagram 結構圖 Examples例如 40 FMEA ? Don39。 利用風險序數(shù) （ RPN） 給失效模式排序 – Should initiate corrective action where needed. 必要時提出糾正措施 8 FMEA Timing of an FMEA FMEA的時機 ? FMEA’s should be initiated when preliminary drawings of the design or process are available 當初步的設計圖紙和工藝被制定出來時應開始做FMEA ? Updated as identified issues are resolved 當被發(fā)現(xiàn)的問題解決後要更新 FMEA ? Can be used on existing products to improve quality 可用於現(xiàn)有的產(chǎn)品以提高質量 9 FMEA ? System系統(tǒng) – Wiring harness 線束 – Electronic module 電控模塊 – Assembly 總成 System FMEA treats system as a“functional schematic” 系統(tǒng) FMEA從 “ 功能關係圖 ” 入手來考慮 10 FMEA An analytical tool used to identify systemlevel failure modes, and identify corrective actions to be taken. 是一種分析工具用來識別系統(tǒng)失效模式 11 FMEA ? It is similar to a Design FMEA, but focuses on the circuit schematic instead of physical failure of ponents. 同 DFMEA相類 似 , 系統(tǒng) FMEA側重於回路設計而不是元件的物理失效 。t wait for the customer to plain if you can avoid it! FMEA是 預防性 的，不是反應性的。應當儘量避免失效，而不是等著顧客提出申訴！ 5 FMEA FMEA reduces the chance that a customer will see a failure FMEA通過以下措施減少顧客遇到失效的情況 : – By defining failure in terms of what the customer wants and expects. 針對顧客的要求和期望確定失效 – By showing where measures need to be taken to prevent failure. 指出爲了防止失效，需要在哪方面採取措施 6 FMEA Types of FMEAs 類型 ? Design – used to analyze product designs before they are released to production 設計 用於在產(chǎn)品投產(chǎn)前對設計的分析 ? Process – used to analyze manufacturing processes 過程 用於分析製程 ? System – used to analyze systems in the early concept and design stages 系統(tǒng) – 用於分析早期的概念和設計階段的系統(tǒng) 7 FMEA Summary 概要 – Identifies known and potential failure modes。 Take electrical systems as examples. 以電氣系統(tǒng)為例 。t fet auxiliary functions as well a primary functions 主要功能和輔助功能都要考慮 ? Often, ponents work together to perform a function 經(jīng)常是幾個零件共同實現(xiàn)一個功能 ? Hint: Use the Block Diagram! 提示 : 利用結構圖 List The Function(s) of Each Component 列出每個要素的功能 41 FMEA ? A defect, flaw, or other unsatisfactory condition in the product that is caused by a design weakness 由於設計缺陷造成的產(chǎn)品缺陷 ,瑕疵或其它令人不滿意的情況 ? Typical Failure Modes: 典型的失效模式 Breaks Cracks 破碎 裂紋 Corrodes Sticks 腐蝕 粘結 Deforms/melts 變形 /熔化 42 FMEA ? Start with the previous two steps: 從前両個步驟入手 : – Functions 功能 – Quality requirements 質量要求 43 FMEA ? In your own descriptive words, write down the following scenarios， 用自己的語言描述下列假設 ： Failure = No function， 失效 = 無功能 Failure = Not enough function， 失效 = 功能不足 Failure = Too much function， 失效 = 功能過強 ? Similarly,同樣 ： Failure = No quality requirement 失效 = 未達到質量要求 44 FMEA ? An effect can be ， 後果可能是 ： – Complete loss of function， 功能完全喪失 – Degradation of performance or quality 性能或質量下降 ? Many failure modes have more than one effect! 許多失效模式不止有一個後果 ！ ? Effects of failure often show up as a chain of events, from immediate effect to the ultimate effect on the customer 失效模式的後果經(jīng)常表現(xiàn)為對客戶的一連串的影響 ,包括直接的後果和最終的後果 45 FMEA Determine Potential Cause(s) of Each Failure Mode 確定每種失效模式的潛在原因 ? A cause of failure is a design weakness that leads to the failure mode 造成失效的原因是由於 設計缺陷 引起 – Inherent in the way the product was designed 是產(chǎn)品設計所固有的 – Relative to the usage of the product 與產(chǎn)品的使用方法有關 ? Many failure modes have multiple causes! 許多失效模式有多個起因 ！ 46 FMEA If the design asis were to go into production. 如果依據(jù)現(xiàn)有設計進行生產(chǎn)的話 ? Use historical data， 利用歷史資料 ? Take improvements into account， 參考已有的改進 ? Consider the lifespan of the product， 考慮產(chǎn)品的壽命 ? Use reliability models and parison with similar products， 利用可靠性模型並與類 似 產(chǎn)品比較 Assess The Likelihood of Occurrence of Each Cause 評估每種原因發(fā)生的可能性 47 FMEA ? There are three types of design controls: 設計控制有三種類型 ： (1) Those that prevent the cause of failure。t leave the space on the form blank. Write None 不要在表上留下空格不填。 覺察產(chǎn)生失效的原因 ； (3) Those that detect the failure mode(s) 檢測失效模式 48 FMEA Detection R