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1、,1,設計失效模式及效应分析Design Failure Mode&Effect Analysis(DFMEA),2,FMEA 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: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,以及由此产生的效应Identify a
2、ctions 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Document the process 将以上过程记录在案,3,FMEA Flow/FMEA 流程,Boundary Diagram,Interface Matrix,P-Diagram,FMEA(with Robustness Linkage),Robustness&Reliability Checklist,Design Validation Plan(DVP),Q
3、ualifies and clarifies the relationships between systems,Identifies and quantifies the strength of system interactions,Identifies noise and control factors and error states,Summarizes error states,noise factors,and associate design control,4,Magna Closures Required FMEA Related Documents,Boundary Di
4、agramP-DiagramCC/SC/KCProduct Characteristic MatrixFMEA Checklist,Interface MatrixDFMEAProcess Flow DiagramPFMEADVP&R,5,A Boundary Diagram Example(U204 Liftgate Latching System),Liftgate Latch Assembly,Ajar Switch,Brainplate,Lock Actuator,Plastic Security Shield,Glass Latch,O/S Handle Assembly w/Rod
5、,Wire Harness,GEM,Assembly Plant,Owner/Operator,Vehicle Body,Inner Door Trim,Water Shield,Door Seal System(door effort),Striker Assembly,C-pillar sheet metal with paint,Fasteners,Window Glass clearance,Sheet Metal Outer,FCSD(Service),Fasteners,6,A P-Diagram Example(U204 Liftgate Latching System),U20
6、4 Liftgate Latching System,Signal Factors1)Door Slam Engergy2)Handle release effort Liftgate3)Handle release travel Liftgate4)Handle release effort Glass5)Handle release travel Glass6)Outside release handle cycling,Control FactorsLatch material selections-Frameplate-Housing-Ratchet&PawlRatchet&pawl
7、heat treat:36-42 HRCComponent finishSpring material selection,Ideal Function Response1)Latch releases2)Latch retains striker fully,Error State Response1)Latch no function2)Striker not aligned with latch3)Striker not properly engaged4)Gap issues with trim5)High/low release effort6)High/low release tr
8、avel7)Inside/outside release handle not functioning,Noise Factors,Piece 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 body,Customer Usage:1)Handle cycle loads/Abuse2)Door slam speed,Sub-system interactio
9、n:1)Inner/outer sheet metal2)Latch assembly3)Outside release handle assy4)Linkage5)Electrical connector,Aging/Wear Effect:1)Fatigue2)Creek3)Impact durability4)Corrosion,Environment:1)Temperature2)Humidity3)Dust4)Vibration5)Ice,7,An Interface Matrix Example(Headlamp),P:Physical touching E:Energy Exch
10、ange I:Information Exchange M:Material Exchange,Numbers 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 absolutely necessary for functionality 0:Interaction does not affect functionality
11、-1:Interaction causes negative effects but does not prevent functionality-2:Interaction must be prevented to achieve functionality,Negative values are analyzed for recommended functions.,8,DFMEA设计失效模式及效应分析,Design Potential FMEA is:设计潜在失效模式及效应分析是:an analytical technique used primarily by Design-Respo
12、nsible 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apply to system,subsystem,and component应用于系统、子系统及部件,9,Customer of DFMEA顾客的定义,Customer for a
13、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,10,Team Effort 小组的努力,Design 设计Manufacturing 制造Quality 品质Material 材料Reliability 可靠性Sub-contractor 分供方,11,DFMEA 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 o
14、r 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,12,DFMEA 设计失效模式及效应分析,Assumption:Design will be manufactured/assembled 假设:该设计将按此意图进行生产Potential failure modes during prod
15、uction“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 space 装配空间Tolerances/capability 公差/过程能力,13,Development of a Design FMEA 设
16、计FMEA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?,14,Development of a Design FMEA设计FMEA的开始,Source of information 资料来源QFD 质量功能展开Product Requirement 产品要求Manufacturing requirement 生产要求,“Design Intent”“
17、设计意图”,15,Block Diagram 框图,DFMEA Recommended tool:Block DiagramDFMEA建议工具:框图,Snap fit 卡扣连接,滑动配合,16,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,16,17,18,19,20,21,22,_ System_ Subsystem,POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS(Design FMEA),FMEA Number_,Core Team_,17,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,
18、16,17,18,19,20,21,22,_ 系统_ 子系统,POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS(Design FMEA)潜在失效模式及后果分析(设计FMEA),FMEA 编号_,核心小组_,功能,18,Details of DFMEADFMEA的詳細內容,19,Design Objectives:Minimum 3000 hours of riding without need for maintenance and 10,000 hours of riding for design life.Accommodates maleadults
19、 comfortably to the 99.5th percentileectFunction:Ease of usePotential Failure Mode(s):Difficult to steerDifficult to pedalFunction:Provide reliable transportationPotential Failure Mode(s):Chain breaks frequentlyTires require frequent maintenanceFunction:Provide comfortable transportationPotential Fa
20、ilure Mode(s)Seating position is not comfortable,Function:Provides stable attachment for seat supportPotential Failure Mode(s)Structural failure seat support Excessive deflection of seat supportFunction:Provides pleasing appearancePotential Failure Modes(s)Finish(shine)deterioratesPaint chips,Handle
21、 Bar Assembly,Rear Wheel Assemble,Sprocket Assemble,Function:Provides structural supportPotential 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 fr
22、ame mounting points too shortFunction:Support frame assembly production methods(welding)Potential Failure Mode(s):,Bicycle,Frame,Front Wheel Assemble,Seat Assemble,Chain Assemble,Upper Frame,Lower front Tube,Lower Rear Tube,Sprocket Tube,System Level,Subsystem Level,Component Level,20,设计目标:骑行至少3000小
23、时无需保养,设计寿命为骑行10000小时。适于第99.5百分位成年男子骑用,舒适便利。3.等等.功能:便于使用潜在失效模式:方向把不好用脚踏板不好用功能:提供可靠的交通运输潜在失效模式:链条经常断开需要经常修理车胎功能:提供舒适的交通运输潜在失效模式:车座位置不舒服,功能:为座位支撑提供稳定的附属物潜在失效模式:座位支撑的结构性失效座位支撑的过大变形功能:提供好看的外观潜在失效模式: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:提供结构性支撑潜在失效模式:结构性失效过大变形功能:对正确的车架几何外形提供尺寸控制潜在失效模式:车架安装点的长度过长车架安装点的长度过短功能:为车架
24、总成的生产方法(焊接)提供支持潜在失效模式:,自行车,车架,前轮总成,车座总成,链条总成,上部车架,下前车管,下后车管,链轮管,系统等级,子系统等级,部件等级,21,Details of DFMEA,22,Details of DFMEADFMEA的详细内容,23,Details of DFMEADFMEA的详细内容,24,Details of DFMEADFMEA的详细内容,25,Details of DFMEADFMEA的详细内容,26,Details of DFMEADFMEA的详细内容,27,28,29,Details of DFMEA,30,Details of DFMEADFMEA
25、的详细内容,31,Details of DFMEADFMEA的详细内容,32,Details of DFMEADFMEA的详细内容,33,Details of DFMEA,34,35,Details of DFMEADFMEA的详细内容,36,Detail of DFMEADFMEA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：failure OR the failure mode fromoccurring,or reduce
26、 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。,37,Detail of DFMEADFMEA的详细内容,Detection:Detect the cause/mechanism of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，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。,38,Detail of DFMEADFMEA的详
27、细内容,39,40,41,Detail of DFMEADFMEA的详细内容,42,Detail of DFMEADFMEA的详细内容,OBJECTIBVE主要目的“Reduce risks and increase customer satisfaction by improving the design”建议措施的主要目的是通过改进设计,降低风险,提高顾客满意度。,43,Detail of DFMEADFMEA的详细内容,Typical recommended action应考虑但不限于以下措施：Revised design geometry/tolerance 修改设计几何尺寸和/或公差
28、Revised Material Specification 修改材料规范Design of Experiments(particularly when multiple or interactive causes are present)or other problem-solving techniques,and DOE 试验设计(尤其是存在多重或相互作用的起因时或其它解决问题的技术)，和Revised test plan 修改试验计划,44,Impacts of actions on(S),(O)&(D)(S),(O)&(D)的减低措施,45,Detail of DFMEADFMEA的详
29、细内容,46,Detail of DFMEADFMEA的详细内容,47,Follow-up Actions跟踪措施,The design-responsible engineer is responsible for ensuring that all actions recommended have been implemented or adequately addressed.负责设计的工程师应负保证所有的建议措施已被实施或已妥善落实。The FMEA is a LIVING document and should always reflect the latest design level as well as the latest relevant actions,including those occurring after start of production.FMEA是一个动态文件,它不仅应体现最新的设计水平,而且还应体现最新相关施,包括开始生产所发生的措施。,
