Process Failure Modes and Effects Analysis (PFMEA) Training

1 Process Failure Modes and Effects Analysis (PFMEA) TrainingNovember 2003 PFMEA is a PFMEA?lA Process Failure Modes and Effects Analysis provides a structured, qualitative, analytical framework which taps the multi-disciplined experience of the team to brainstorm answers to such questions as:lHow can this Process , function, facility, or tooling fail?lWhat effect will Process , function, facility, or tooling failures have on the end product (or customer)?lHow can potential failures be eliminated or controlled?lBased on the success of Failure Modes and Effects Analysis (FMEA), the PFMEA concept was developed to incorporate a broader Analysis team to accomplish a thorough Analysis in a short timelA PFMEA can be used to assess any Process . The most common use of the PFMEA involves manufacturing processeslPFMEA smay be performed on new processes or to improve current processeslTo maximize its value, a PFMEA should be performed as early in the manufacturing development cycle as possiblePFMEA is a PFMEA?

2 (cont)lBecause most PFMEAs involve manufacturing area processes, the manufacturing engineer is usually the team leaderlThe effectiveness of the team depends upon the expertise of its members, and the quality of the team output depends on the willingness ofeach team member to give his or her best effortlTeams may include:lManufacturing EngineerlDesign EngineerlTooling EngineerlSystem Safety EngineerlIndustrial EngineerlHandling SpecialistlLine Foreman/OperatorslCustomerlMaterials & Process EngineerlOthers as requiredPFMEA to Conduct an Effective PFMEAlPrior to the first meeting, the team leader shouldlEstablish objectives and scopelChoose experts for the PFMEA teamlThe team leader is responsible for the effectiveness of the reviewlBrainstorming used to increase creativity and bring out a wide range of ideaslDiscussion allows team to look at things from different view pointslA visit(s) to the work area with an overview of the Process / test/ operation gives team members basic understanding of the processlLimit meetings to one hourPFMEA to Conduct an Effective PFMEA (cont)lSTEP 1lTeam leader organizes the team; defines the goals, methods, scope, responsibilities of each team member.

3 And establishes a tentative schedulelAfter reviewing engineering, drawings, and planning, team develops a flow chart showing the major functions or operations of the Process to help team members understand the processlSTEP 2lFor each Process function, team determines all credible Failure modeslTeam discusses and records the Failure Effects , Failure causes, and current controls for each potential Failure modelTeam rates occurrence, severity, and detection for each Failure causelIt is helpful to rate all Failure causes for occurrence first, next rate for severity, and then rate for detectionlThe Risk Priority Number (RPN) is the product of these ratingsPFMEA to Conduct an Effective PFMEA (cont)lSTEP 3lIdentify corrective action to improve the Process /testlFailure causes with the highest RPN should be analyzed firstlHigh occurrence number indicates the causes should be eliminatedor controlledlHigh detection number indicates a need for additional controlslHigh severity number indicates product or Process redesign may be neededlConduct additional brainstorming to develop effective and innovative ways to reduce failurelProposed changes identified as Resulting Action Taken and new occurrence, severity, detection, and RPN ratings are assignedPFMEA to Conduct an Effective PFMEA (cont)lSTEP 4lProposed changes for high/significant RPN ratings that have not been completed are listed on the PFMEA form as Open Work Preventive Action Report (PAR)

4 Required along with applicable name and organization lPFMEA team reaches agreement on items to keep open and carry forwardlAll Open Work PAR Required items will be included in the executive summary of the PFMEA TWRlIndividual members will be responsible for the implementation oftheir respective Open Work itemslPresenting the PFMEA results to management and releasing the final report completes the PFMEA effortPFMEA Team OrganizationlPFMEA team members are assigned to function as team leader, scribe, recorder, and facilitator lTeam Member uses personal knowledge, expertise, and perspective; participates in meetings helping the team reach full potentiallChecklistlBe preparedlBe innovative Ask questions, challenge assumptionslComplete and close all action items assignedPFMEA Team Organization (cont)lTeam Leader responsible for planning, organizing, staffing, and chairing; ensures a thorough and credible PFMEA Analysis is performedlChecklistlSelect 5-10 team members to represent engineering organizations and/or work operations involvedlSelect appropriate team members to function as scribe, recorder,and facilitatorlPrior to the first team meetinglDevelop scope for PFMEAlReview PFMEA guidelines and formslDevelop schedulelResolve any questions about performing the PFMEAlDistribute guidelines, objectives, scope, and schedule to each team memberlAfter each team meeting, review team s progresslEnsure any required changes in engineering, planning, etc.

5 Are included in team s recommendationslPrepare final report and report all open action itemsPFMEA Team Organization (cont)lScribe record team members comments on white board or flip chart as the team brainstormslRecorder record team s thoughts as listed on board/chartlChecklistlRecord points outlined on white board or flip chartlExpand, summarize, and/or edit the ideas as they are recordedlProvide notes to the team leader or draft team minutes accordingto the team leader s directionlHelp complete PFMEA work sheetslChecklistlDocument comments on white board/flip chartlGet team concurrence with what was documentedlClarify comments as necessaryPFMEA Team Organization (cont)lFacilitator the system safety/reliability engineer is generally the PFMEA facilitator. The facilitator supports the team by enhancing Process consistencylChecklistlProvide copies of PFMEA instructions and other materials to the team leaderlAssist team leader in evaluating team performance as requestedlFunction as a consultant throughout the PFMEA analysislAssist team leader and team in effectively utilizing PFMEA analysisPFMEA Form and DocumentationlThe PFMEA form provides the structured format for meetings, Analysis , and documentation of findingslTwo variations of the form are available.

6 Use depends on the complexity of the Process and/or potential need for reviewlLong form includes follow-up documentation for evaluation of initial recommendations:lFirst time Process reviewlNew processes lMajor Process enhancements or changeslShort form used for:lRepeat evaluated lSimple processesPFMEA Training12 Process Failure Modes and Effects Analysis (PFMEA) Long FormPROCESS:DATE: Process FunctionPotential Failure ModePotential Effects of FailurePotentialCause of FailureCurrent ControlsRecommended ActionsRPNR esponsible Activity and StatusSEVOCCDETRPNSEVOCCDETL egend:OCC = occurrenceDET = detectionSEV = severityRPN = Risk Priority Number PFMEA Training13 Process Failure Modes and Effects Analysis (PFMEA) Short FormPROCESS: Process FunctionPotential Failure ModePotential Effects of FailurePotentialCause of FailureCurrent ControlsRecommended ActionsRPNSEVOCCDETL egend:OCC = occurrenceDET = detectionSEV = severityRPN = Risk Priority Number DATE:PFMEA Form and Documentation (cont)lPotential Failure Modes list all credible Failure Modes or ways the Process /test can fail before addressing Failure Effects and Failure causesl What can possibly go wrong with this Process /test?

7 L How can the part (component, assembly, or product) fail to meet the engineering criteria or specification? lIn each instance, the assumption is made that the Failure could occur, but will not necessarily occurlEach Failure mode should be crediblelDo not list acts of God or freak accidentslExamples of Failure Modes includeBentCrackedContaminatedLoosenedLe akageDamagedDeformedGougedMisalignedCorr odedBroken ToolingWrong ToolingWrinkledScratchedHumidity Handling DamagePFMEA Form and Documentation (cont)lPotential Effects of Failure assuming the Failure mode has occurred, list all potential Failure Effects of the Process failurelWorst case Effects such as leakage past an O-ring seal should be considered firstlLess serious Failure Effects such as rework schedule impact may then be notedlIn each case, understand that a Process Failure can affect the immediate Process , the subsequent processes, the end item, end item users, or the customerlPotential Failure Causes Failure cause of each potential Failure mode should be thoroughly discussed and listed by the teaml What conditions can bring about this Failure mode?

8 PFMEA Form and Documentation (cont)lCurrent Controls usually verification techniques; list all controls intended to detect or eliminate the Failure causes thus preventing the Failure mode from occurringl If a defect or Process Failure occurs, will it be detected or prevented by the current controls ?lIf current controls are adequate, no corrective action is neededlIf current controls are not adequate, corrective action should recommend additional or enhanced controlslQuantitative vs Qualitative Evaluation evaluating failures for occurrence, severity, and detection may be accomplished using quantitative or qualitative techniques the two methods should not be combinedlQuantitative approach relies on numerical datalQualitative approach relies on team members experience, judgment, involvement, and participationPFMEA RatinglWhen estimating the occurrence rating, consider the probability that the potential Failure causewill occur and thus result in the indicated potential Failure modelDisregard detection at this point in the processOccurrence Rating Criteria1 Low probability of occurrence.

9 Relatively few failures have probability of occurrence. Occasional Failure , but notin major proportions High probability of occurrence. Process has experienced higher than normal Failure rate 7-8 Very high probability of occurrence. Process Failure is almost probability of occurrence. The team is not aware of thisfailure having ever RatinglSeverity is the factor that represents the seriousness or impactof the Failure to the customer or to a subsequent processlSeverity of Failure relates to Process Failure Effects and is independent of occurrence and detectionlSeverity of a Failure effect is therefore the same for all Failure causeslSeverity should be considered as though no controls are in placeSeverity Rating Criteria1 Low severity rating. Failures have minor effect on further processing or product severity rating. A Failure that causes customer concern or program impact, but will not cause a Criticality 1 Failure of the end item or anequivalent Process severity rating.

10 Failure causes severe impact to componentor Process and may contribute to a Criticality 1 Failure of the end item or an equivalent Process high severity rating. Failure contributes to a known or highly probable Criticality 1 Failure of the end item or an equivalent Process Failure involving loss of life or a major loss of manufacturing facilities10 Failure would have very little effect on further processing or product RatinglEstimate probability of detecting a Process or product defect (caused by the Failure identified) before the part/component/assembly leaves the manufacturing locationlConsider only the controls contained within the Process planningDetection Rating Criteria1 Low probability of product leaving the manufacturing area containing the defect. The defect is easily probability of product leaving the manufacturing area containing the defect. The defect is somewhat more difficult to detect.