FAILURE MODE and EFFECTS ANALYSIS 失 效 模 式 及 其 影 响 分 析,Philips CFT Asia Pacific Innovation ,SxOxD,RPN125,SODDescription Action? 1011Failure unlikely to reach user 1101Frequent Minor, detectable failure 1110Minor defect reaches user infrequently 10101Serious and frequent failure 11010Frequent minor defect reaches user 10110Serious defect reaches user 101010IN TROUBLE!,Step 5 - Establish Actions and Responsibilities,1. What has to be improved : - change of design - life test - contact with supplier - control point build in, in production process etc. 2. Who is responsible 3. When is it finished,RPN acceptable?,Corrective actions,DO,New RPN1,Acceptable?,End,Yes,No,No,Yes,RPN acceptable?,Corrective actions,DO,New RPNn,Acceptable?,End,Yes,No,No,Yes,Choice of Corrective Actions,Unlikely to be effectivePreferred choices *Increase inspection *Poka-yoke (fool-proofing) *Additional test*Process change *Additional check*design change *Re-train operators*Automation *Re-write SOP*Computerisation * Robotics,Corrective Action Preference Hierarchy,The intent of any recommended corrective action is to improve the RPN rating by reducing Severity, Occurrence, Detection or all 3 together. Emphasis should be on prevention, i.e. reducing Occurrence. Should prevention be impossible, the following Hierarchy of preference should be used: 1. Prevention, or potential cause elimination 2. Detection, as early in the product life cycle as possible: best at the design stage next best prior to mass production then prior to shipment and, as last resort in the field, prior to catastrophic failure 3. Impact reduction, i.e. reduce Severity Generally, to reduce any of the three rating - O, D, S - process and/or design changes/modification are required,FMEA,is is not * structured* a show-piece * systematic* a number game * rigorous* a guessing game * comprehensive* a documentation exercise * scientific* a self-consolation exercise * a discipline. * preventive. * customer-focused. * a team effort. * a cross-functional exercise. * a living document. * a continuous process* a one-off exercise,Real Life FMEA Exercise,3PRODUCT D-FMEA,Process FMEA vs Product D-FMEA,*P-FMEA does not rely on product design changes to overcome process weaknesses, but it does take into consideration a products design characteristics *D-FMEA does not rely on process controls to overcome design weaknesses, but it does take the technical/physical limitations of the manufacturing process (i.e. the process capability) into consideration.,Process step,Purpose,Piece-part or sub-assy,Function,Process FMEA,Product FMEA,Process FMEA vs Product D-FMEA,*Hence causes such as “operator not inserting resistor properly” noisy; jerky; cannot what the customer would observerun at high speed and/or experience Next higher level effectseffects on the engineover-heated; vibration Local effectseffects on the valve itselfdeterioration,MATERIAL,USE,DESIGN,COMPONENT,SPECIFICATION,ENVIRONMENT,PRODUCT,Product Cause - Effect Investigation,Product Functions,Product Functions,Product Functions,Severity (D-FMEA),RatingDegreeEffects 1Minor* no perceptible effect on product performance * user will probably not notice the failure 3 low* customer notices slight deterioration in performance * causes slight customer annoyance 5 Moderate* causes some customer dissatisfaction * customer notices reduced product performance * gradual performance deterioration 7High* high degree of customer dissatisfaction * loss of sub-system function, eg. engine fail 10 Very high* safety-related * non-compliance with government regulations,Occurrence (D-FMEA),RatingDescriptionProbability of failureDesign life failure rate 1RemoteFailure unlikely 1 ppm 3Low Relatively low failure rate 200 ppm 1000 ppm 5ModerateOccasional failures2500 ppm 1 in 80 (1.25%) 7HighRepeated failures 1 in 40 (2.5%0 1 in 20 (5.0%) 10Very highFailure almost inevitable 1 in 8 (12.5%) 1 in 2 (50.0%),Detection,ApproachDescription Application Time-tableHow early in product life cycle D-FMEA from design start to Field failure ? Fixed-gateWhats the probability of detection D-FMEA at any point (gate) in the cycle ?,Detection (D-FMEA),Time-table approach Rating Probability of detection 1 Will be detected prior to Production Release 3 Very likely to be detected prior to Final Release 4 Detectable after release but before Mass Production 5 Detectable prior to Shipment 7 Will be detected before occurrence in the field 10 Undetectable until failure occurs in the field,Detection (D-FMEA),Fixed Gate approach Rating Probability of detection 1 Will be detected in design evaluations 3 High chance of detection in design evaluations 5 Moderate chance of detection in design evaluations 7 Low chance of detection during design evaluations 10 Undetectable until failure occurs in the field,4ORGANIZATIONAL ASPECTS OFFMEA,Organisational Aspects of FMEA,General Points Participants Preparations Reporting,FMEA is a team effort covering all rel