Failure Effect Mode AnalysisGreat question; a confusion in estimationTacoma Bridge CollapseIntroduction to FMEABenefits of FMEASlide 6Do you know?ReliabilityFailures are not very well understoodDifferent types of FMEAThe Pre-workGuide to do FMEAFMEA WorksheetTerms and DefinitionsDef. Cont… Failure ModeDef. Cont… Failure EffectDef. Cont… Severity (SEV)Def. Cont… Failure CauseDef. Cont… Occurrence (O)Def. Cont… Current ControlsDef. Cont… Detection (D)Def. Cont… Risk Priority No (RPN)Pareto DiagramRecommended Actions and ResultsDevelopment TeamLink with continuous improvementFMEA TimingUses of FMEATQM PrinciplesSlide 30LimitationsFMEA ConclusionResourcesFailure Effect Mode AnalysisByRajeevKishoreUrosGreat question; a confusion in estimationHow a raw egg bounce?Tacoma Bridge CollapseGondola FMEAIntroduction to FMEA•To introduce new products or manufacturing processes successfully in a cost-effective manner, resources should be allocated up-front to prevent problems. •Fixing the problem after a product is manufactured is more expensive than it is to prevent them.Benefits of FMEA•Reduce the number of engineering changes•Reduce product development time•Lower start-up cost, and reduces warranty•Greater customer satisfaction•Increased cooperation and teamwork between various functions•A well-documented project history and information databaseDo you know? “Failure Modes...” is a misnomer — some sources now call FMEA by another name: “Fault Hazard Analysis.”Reliability•Failures are expensive•System flakiness is a major source of user frustration- 25% in survey have seen peers kicking their computers- 2% claim to have hit the person next to them in their frustrationFailures are not very well understoodNo Publicly available data on failures on real systemsWHY?Different types of FMEA•Design (DFMEA): technique used primarily by a Design Responsible Engineer/Team as a means to assure potential failure modes, causes and effects have been addressed for design related characteristics•Process (PFMEA): technique used primarily by a Manufacturing Engineer/Team as a means to assure potential failure modes, causes and effects have been addressed for process related characteristicsThe Pre-workProcess or Prepared By ____________Product Name _____ Page ________of ________Person Responsible __________________ FMEA Date (Orig.) _______ Revised _______Guide to do FMEAFMEA WorksheetFunctionFailure modeFailure effectS Failure CauseO Current ControlD RPNRec. ActionsS O D RPN1.2.Terms and Definitions•Fault•Failure•Function/Process•Examples – 1. Pencil Sharpener 2. Oil changing processDef. Cont… Failure Mode•The way failure occurs•Can cause a failure mode in another item•Identify and list possible failure modes•Examples –1. Frequently breaking the graphite2. Wrong type of oil or No oil addedDef. Cont… Failure Effect•Immediate consequence of a failure•Effects can range from very small to major disasters.•Examples –1. Improper writing2. Engine wear or Engine FailureDef. Cont… Severity (SEV)•Worst consequence of a failure•How is it determined?•Standard scale from 1 (no danger) to 10 (very severe)•Prioritize the failures modes and their effectsDef. Cont… Failure Cause•Design weakness - How the failure could occur?•Listed in technical terms and are documented•Examples – 1. Improper mixture of Graphite and Clay 2. Misread oil chart or HurryingDef. Cont… Occurrence (O)•Probability of the cause occurring•Look for similar products or processes•Probability number scale from 1 (not likely) to 10 (inevitable)•Detailed development section of FMEA ProcessDef. Cont… Current Controls•Current controls that prevent the failure cause (before causing effects)•Examples – 1. improve quality of graphite 2. No control or engine lightDef. Cont… Detection (D)•Assessment of the likelihood that the current controls will detect failure cause or failure, before it reaches the customer.•Different techniques are used by an engineer•Identify the detection number ‘D’, ranging from 1 (easily detectable) to 10 (cannot detect)Def. Cont… Risk Priority No (RPN)•RPN = S * O * D•Risk that has greatest concern can be identified •Failures are prioritized according to:- Severity- Occurrence - Detection•Requires additional planning or actionPareto DiagramRecommended Actions and Results•Address potential failures that have a high RPN•Are any further actions required?•Assign new value for S, O and D, and calculate new RPN value•Update the FMEA as the design or process changesDevelopment Team•Crucial step in FMEA •FMEA is a team function- Formulate cross functional team- Understand customer requirements – both internal and external inputs- All team members walk and observe the process- Make notes or observationsLink with continuous improvementFMEA Timing •FMEA should be updated whenever:- At the conceptual stage - Changes are made in the design - New regulations are instituted- Customer feedback indicates a problemUses of FMEA•Development of methods to design•Test systems to ensure that the failures are eliminated•Tracking and managing potential risks•Ensuring that failure will not injure customer or impact a system•Evaluation of customer reviews on the problems indicatedTQM Principles•Continuous Improvement Process•Continued building and prevention of failure on the process•Employee Involvement and Empowerment•Employees can feel empowered and involved if they correct an error in a process or part.•Leadership•There needs to be a team leader for every group, which is assigned to one part of the process.TQM Principles•Performance Measurement•RPN, lower the better•Supplier Partnership•If one supplier has bad parts, it directly affects your products, by creating failure in your company. •End Customer Satisfaction•Reliability meets customer requirementsLimitations•FMEA is limited by the team experience•FMEA may only identify and avoid major failure modes•Multiplication of rankings may result in rank reversalsFMEA Conclusion•Purpose of FMEA, is the process of identifying potential failure modes and their associated causes, assigning severity, Occurrence, and Detection ratings, and calculating RPN•RPNs should be used for continuous improvement
View Full Document
Unlocking...