Part 2: Using FMEA, DFR, Test And Failure Analysis In Lean NPD
Part 2:Using FMEA, DFR, Test andFailure Analysis in Lean NPD
Overview Introduction and Definitions Part 1: Lean Product Development– Lean vs. Traditional Product Development– Key Elements of Lean NPD Customer Defines Value Front Loaded and Knowledge Based Eliminate Redesign Waste– Reliability Requirements Part 2: Reliability Elements of Lean NPD–––––Lean FMEA and DRBFMCritical CharacteristicsDFR and Physics of FailureAccelerated Testing to FailureFailure Analysis and Knowledge Capture
Lean FMEA Some teams attempt to lean FMEAprocess by creating product family FMEAsbut fail to update FMEA for newapplications or changes Instead Lean FMEA Should Focus on NewDesign Features and Changes to BaselineDesign to Assess Associated Risks
Tools to Focus Lean FMEA Diagramming Tools– Functional Block Diagram– Boundary Diagram– Parameter Diagram– Process Flow Diagram Highlight Changes to Product or Processon the Diagrams
Functional Block DiagramAnnotate Retained and Changed Items & Functions
Boundary Diagram ConstructionSubsystem 1Subsystem 3Subsystem 2Consider a Functional Block Diagram of the SystemWith Modules and InterfacesInterface-Physical Interface-Info Transfer-Data Transfer-External InputFMEA Boundary
Parameter Diagram ofProduct, Process, SystemNoiseFactorsSignal(Inputs) Controlled by Input Function Forces Beyond Control Cause Output Variation Environment FactorsProduct, Process,or System Static or Dynamic May be VariableControl FactorsResponse(Output, Function) Performance Mean, Std Dev Customer Requirement Functional Design Parameters Fixed or Adjustable Fundamental to Design of Function Reduce VariationElements of the P-Diagram
Process Flow DiagramAnnotate Retained and Changed Process Steps
Selecting Process Steps for Analysis On Process Flow Map:– Identify Steps Being Modified– Identify New Steps Required for New Product Drill Down to Identify Sub-Steps Within theTarget Steps Identified for Analysis Complete Lean PFMEA on SelectedProcess Steps Integrate with Previous PFMEA onStandard / Unchanged Process Steps
Key Characteristics Include:– Product Features– Manufacturing Processes– Assembly Characteristics That Significantly Affect:– Product Performance– Form, Fit, Function Lean NPD Focuses on the Critical FewCharacteristics the Customer Values
Key CharacteristicsRequirements Documents Customer Specification Regulatory Dimensions AppearanceOPotentialcCause(s)/cMechanism(s)uOf FailurerCurrentDesignControlsPrevent DetectDetecRPNAction ResultsResponse &Recommended TargetS O D RActionActionsCompleteE C E PTakenDateV C T NDFMEA &PFMEAPotential Critical and SignificantSpecial CharacteristicsMatrixDirection of ImprovementWeighted ImportanceHHY081817209Technical Requirements,Tools Identify SpecialProduct Characteristics1.090 TO 1.110 " FACE OF PRIMARY HOUSINGBUSHING TO FACE OF JACK SHAFT5SEALDOWEL PINS 0.260 TO 0.270 " TO3FACEJACK SHAFT SEAL AGAINST 9SHOULDERBEARING FLUSH TO SNAP RING FACE3SEAL COMPRESSION HEIGHT 9PRIMARY GASKET SEAL SURFACE9FINISHFFSERATION DAMAGE5Process StepsPrimary Drive Manufacturing Process StepsGFFFHGH HFHH0ClassGF 90000000Sev0PotentialEffect(s) ofFailureOp 100 Step 1PRE-LOAD DOWEL PINS TOFIXTUREOp 100 Step 2PRE-LOAD JACK SHAFTSEAL TO FIXTUREOp 100 Step 3PRE-LOAD PRIMARYHOUSING BUSHING TOFIXTUREOp 110Pre-load bearing to fixture #2Op 120Pre-load main shaft oil seal tomandrelOp 200Housing to fixture #1Op 210Operate pressOp 220Retaining ring to top grooveOp 230Reload fixture #1Op 300Housing to fixture #2Op 310Operate pressOp 320Retaining ring to top grooveOp 330Mandrel to main shaft bore I.D.OP 340Operate pressOp 350Re-load fixture #2 and mandrelOp 400Housing to tableOp 410ReservedOp 420Chain adj sub assy to housingOp 430Lubricate bushing & sealOp 445Move or stage for final assyOp 10O-ring to shifter tubeOp 500Shifter tube to housingOp 510Clamp to shifter tubeOp 20Assemble shifter leverOp 520Wave washer to shifter leverOp 530Shifter lever to shifter tubeOp 535Que for final assy lineFunctionPotentialFailureMode41Item /ProcessStepSeverityReceive MaterialMaterial handlingShipping DamageComponent ManufactureVehicle AssemblyRequirements DocumentDrawingsRobustness ToolsField History Functional Block Diagram Boundary Diagram P-Diagram Interface MatrixRelative ImportanceCharacteristics Matrix
Identifying Key rencePotential Critical CharacteristicPotential Key CharacteristicPossible Annoyance Zone
Weighted ImportanceMMMMHCharacteristics from Requirements and DFMEAHHHLOp 445Move or stage for final assyOp 430Lubricate bushing & sealOp 420Chain adj sub assy to housingOp 410ReservedOp 350Re-load fixture #2 and mandrelOp 400Housing to tableOP 340Operate pressOp 330Mandrel to main shaft bore I.D.Op 320Retaining ring to top grooveOp 310Operate pressOp 300Housing to fixture #2Op 230Reload fixture #1Op 220Retaining ring to top grooveOp 210Operate pressOp 200Housing to fixture #1Op 120Pre-load main shaft oil seal tomandrelPre-load bearing to fixture #2Op 110HOUSING BUSHING TOFIXTUREOp 100 Step 3PRE-LOAD PRIMARYOp 100 Step 1PRE-LOAD DOWEL PINS TOFIXTUREOp 100 Step 2PRE-LOAD JACK SHAFTSEAL TO FIXTUREVehicle AssemblyComponent ManufactureShipping DamageMaterial handlingReceive Material00000Que for final assy lineOp 520Wave washer to shifter leverOp 530Shifter lever to shifter tubeOp 535Op 20Assemble shifter leverClamp to shifter tubeOp 510Op 500Shifter tube to housingH0Direction of Improvement01.090 TO 1.110 " FACE OF PRIMARY HOUSINGOp 10O-ring to shifter tubeL9M9H45M27M0L0MH0HM0HM35L819SERATION DAMAGEM54PRIMARY GASKET SEAL SURFACE FINISHM09M3SEAL COMPRESSION HEIGHTL261327BEARING FLUSH TO SNAP RING FACE549050SEAL41SHOULDER39FACE0JACK SHAFT SEAL AGAINST72DOWEL PINS 0.260 TO 0.270 " TO81BUSHING TO FACE OF JACK SHAFTSeveritySpecial CharacteristicsMatrix810Potential Critical and SignificantSpecial Characteristics MatrixProcess Steps from Flow ChartProcess StepsPrimary Drive Manufacturing Process StepsCustomerAssessmentRelative ImportanceEffect of Step onCharacteristics
Developing the Control Plan Prioritize Process Risks Identified in thePFMEA and the Special CharacteristicsMatrix Process Flow Diagram Lessons Learned from Similar Processes Process Control Data from RelatedProcesses Measurements Required for Process Control SPC Control Limits Complete the Items in Control Plan Template
Control Plan ItemsMachine, Device, Jig,Tools for Mfg.For each operation that is described, identify the processing equipment machine, device,jig, or other tools for manufacturing, as appropriate.No.Enter a cross reference number from all applicable documents such as, but not limited to,process flow diagram, numbered blue print, FMEAs, and sketches.ProductFeatures or properties of a part, component or assembly that are described on drawingsor other primary engineering info. Compilation of important product characteristics.ProcessProcess variables that have a cause and effect relationship with the identified productcharacteristic. Identify those process characteristics for which variation must becontrolled to minimize product variation. There may be more than one processcharacteristic for each product anceSpecifications/tolerance may be obtained from various engineering documents, such as, butnot limited to, drawings, design reviews, material standard, computer aided design data,manufacturing, and/or assembly ify the measurement system being used, including, gages, fixtures, tools, and/or testequipment required to measure the part/process/manufacturing equipment.SampleWhen sampling is required list the corresponding size and frequency.Control MethodBrief description of how the operation will be controlled, including procedure numberswhere applicable. Operations may be controlled by SPC, inspection, attribute data,mistake proofing, sampling plans, and other. If elaborate control procedures are used,reference document by ID name/number.Reaction PlanSpecify the corrective actions necessary to avoid producing nonconforming productsor operating out of control. May also refer to a specific reaction plan number and identifythe person responsible for the action.
Using the Control Plan For Critical Characteristics, Use ControlPlan to Identify:– Measurements: How, When, How Often– Controls to Keep Characteristic in Tolerance– Actions if Characteristic Out of Tolerance Containment Corrective Actions Robust Design Controlled Processes Reliable Products
DRBFM and DRBTRDesign Review Based on Failure Modes & Test ResultsKey Elements of Mizenboushi(Reliability Problem Prevention)GD3 (Good Design, Good Discussion,Good Dissection)Toyota’s “Creative FMEA” Method
Problem Prevention – GD3 Good Design Robust Design– Design for Reliability (DFR)– Design for Six Sigma (DFSS) Good Discussion Eliminate Risk– Apply Design Review Based on FailureModes (DRBFM) to identify problems anddevelop countermeasures or corrections Good Dissection Effective Validation– Apply Design Review Based on Test Results(DRBTR) to Evaluate Effectiveness. Test toFailure & Analysis of Test Failures is Critical
GD3 Problem ResolutionTotal Problems to be SolvedGood Design(Robust DesignTo PreventProblems)Good DiscussionGood ver& ResolveAll ProblemsBefore Pre-ProductionValidation
DRBFM Approach Elements from FMEA, FTA, and DesignReview– These tools previously used for managementand control of projects– Toyota developed “creative FMEA” approach– Shift focus to improve perceptiveness andproblem solving Focus is on finding and preventingproblems – not completing forms andchecklists (which de-motivate participants)
DRBFM Application
DRBFM is a Forum for ThinkingTeamwork and ParticipationWhat has changed?* What did you change? Why?* What surrounding conditions have changedoutside your control?Concerns about the changes?*Your Concerns? What other concerns?* Draw on expertise and knowledge of past problemsWhen will concerns appear? *Could concerns become causes of failuresor incidents? Visualize concerns & causesWhat effects will there be?*How will causes effect the customer?* Consider effects on the OEM and end userWhat preventive measures*What has been done to assure concerns willhave been & should be taken?not actually appear?*Consider other measures that can be implementedSource: Bill Haughey, DRBFM, Applied Reliability Symposium, June 2007, March 2008
How is DRBFM Done? Preparation for the Design ReviewConducting the DRBFMCapturing the InputsAssigning and Tracking Actions toCompletion
Pre-Work for the DRBFM Design Engineer or Core Team:–––––Functional Diagram, Operating EnvironmentChanges from Previous Baseline DesignDrawings and AnalysisFailed and Sectioned PartsDraft DRBFM with Components / Changes, Concernswith Causes and Factors, Effect on Customer, Designto Eliminate Concerns Participants (Functional Experts):– Perceptive mindset, interest in improving product– Past experience and knowledge on similar items
Capturing the Data
Typical DRBFM SessionSource: A Guide to GD3 Activities and DRBFM Technique to Prevent Trouble, Kano & Shimizu, Toyota 2001
Changes and Results DocumentedSource: Carl Hanser Verlag, QZ, Munich, 4-2005
Linking DRBFM with FMEA DRBFM captures the information neededfor FMEA except scoring Scoring columns can be added to fill needfor FMEA if required by customer orstandards
DRBFM to FMEA (1)DRBFM Form:CItemItemFunctionFMEA FormPotentialOCause(s) /cDPotentialS lFailureEffect(s) ofe aMechanism(s)cDesigntModeFailurev sof FailureuControlsePotentialsCurrentrAdd ScoresecRPN.
DRBFM to FMEA (2)DRBFM Actions& ction ResultsFMEA Form:Add ScoresAdd Scores
DRBFM System IntegrationSource: SAE Paper 2003-01-2877, Shimizu, Imagawa, Noguchi, Reliability Problem Prevention for Automotive Components
Applying DRBFM in Lean NPD Use “Missing Knowledge” Decision Flowfrom Lean QFD as starting point These unknowns and known changesfrom current technology or design are thegreatest risks Focus DRBFM on these unknown andchanged areas during concept andprototype team reviews & IntegrationPoints
Integrating Product & ProcessDesign DFMA – Design for Manufacturing andAssembly Integrated Product and Process FMEA /DRBFM Concurrent Engineering Team Visual Management – Decision Flow andValue Stream Map to Manage Tasks
Impact of Lean Focused FMEA Allocation of Resources Targeted toReduce Highest Risks and Unknowns Impact Product and Process Design Drive Test Planning and Analysis toResolve Issues and UnderstandUnknowns Verify Corrective Action Effectiveness Critical Characteristics and ProcessMeasurement / Control
Lean FMEA Summary Focus FMEA on Changes in Design orProcess Use Supporting Tools to Narrow Focus:– Parameter & Boundary Diagrams– Process Flow Charts– DRBFM Techniques– Characteristics Matrix Use Lean NPD Tools to IdentifyUnknowns, Apply Resources, AssignTasks
Design for Reliability andRobustness
How do we Design-in Reliability? Stress Analysis and Test– Find Product Limits & Understand User Needs– Products fail due to variation or in limit environmentswhere stress exceeds strength– Stress and strength distributions:
DFR Strategies
Stress-Strength vs. Age
Reducing Stress / StrengthInterference Increase strength of the part––––Understand operating environment stressesSelect more robust parts or materialsIncrease design marginSupplement deterministic design with probabilistictools Reduce part strength variability– Understand sources of part variation and deterioration– Controlled production process (SPC)– Protect vulnerable components ROBUST DESIGN CONTROLLEDPROCESSES RELIABLE PRODUCT
Robust Design ToolsDFSS and DFR Tools: Differences and Commonality
Probabilistic DesignApplied Reliability Engineering, Rousch and Webb, Center for Reliability Engineering, University of Maryland, College Park, MD. Jan 2006
Reliability Based DesignOptimization
Elements of Probabilistic Design Understand physics of failure and stressesthat precipitate failure Use predictive modeling and acceleratedtest to failure to estimate probability offailure Consider variability of applied stressesand variability of product strength Eliminate stress-strength interference
Physics of Failure Approach Robust Design Considerations FMEA or DRBFM Methods– Design Review Based on Failure ModesIntegrates FMEA and Design Review Test to Failure and Understand CauseMechanisms Failure Analysis Methods
Understand Physics of Failure What physical phenomenon in the part is causedby the stresses applied? If we understand the root cause, we can improvestrength or reduce variability to prevent ormitigate the failure. Most hardware failures can be traced to fourphysical categories / mechanisms:––––WearCorrosion / ContaminationMechanical Failure (fatigue, vibration resonance, etc.)Overstress (electrical or mechanical, transients)
Physics of Failure Tools Tools Used in Physics of Failure Analysis– Principal Physics Model– CAD Drawings / Solid Modeling– Finite Element Analysis Dynamic Simulation (Transients)Fatigue Analysis (Cumulative Damage)Thermal AnalysisAccelerated TestingSimulation
Design of Experiments (DOE) Tool to Evaluate Design Alternatives Determine Factors and Response May need Two Phased DOE Approach– Fractional Design to Find Main Factors– Full Factorial Design to Evaluate Effects andInteractions on Reduced Set of Factors– Consider Time and Cost Analysis of Results and Optimization ofSolution
Iterative DOE ProcessLarry Gonzales, Raytheon, Experiment Design for Engineers & Scientists, Applied Reliability Symposium, 2009.
Use Trade-Off Curves to CaptureKnowledge Point Data from Analysis and Experiments Relationship Between Key Parameters Apply to Support Design Decisions
Trade-Off CurvesCapture Knowledge from Point Solutions
Trade Off Curve Example
Key is Understanding Methods Build Knowledge of Alternatives– Physics of Failure– Design of Experiments– Design for Robustness and Reliability Enable Better Design DecisionsEliminate or Reduce Redesign Waste
Reliability Testing and DataAnalysis
Phased Robustness Testing Prototype Phase– Accelerated Test to Failure (Well beyond Spec –HALT, Step Stress, Specific Stresses and FailureModes) Design Verification Phase– Quantitative Accelerated Life Test– Selected Qualification Tests Production Validation– Demonstrate Corrective Action is Effective– Validate Final Product Made on Production Tools
Robustness Indicator FigureRequirement orSpecificationIf RequirementExceeds TestResult or hasSmall Margin,Design is NotRobustMargin orRobustness ofDesign FactorFactors(Temperature, Vibration,Humidity etc)(Can be Created in Excel using Radar Chart)Analysis & Test Results forEach Factor on current ornew product
General Approach to AcceleratedLife Test (ALT)Understand Failure mechanismsUnderstand Operating and Design LimitsClarify Use Level Stress ApplicationConduct Qualitative tests like HALT or stepstress tests to define product limits and failuremodes Conduct Quantitative ALT to extrapolate life atuse level conditions– Times to Failure at Accelerated Stress Levels– Use life-stress relationships and distributions
ALT Plan Stresses to be ConsideredLife-Stress Relationship for Each StressApplication Use Level for Each StressUse Level Failure Criteria / ThresholdTest Duration and Resources AvailableConsider Use of DOE to help estimate:––––Stress Factors with Most EffectProbability of Failure at Specified Use LevelProbability of Failure at Maximum StressInteractions to Help Define Life-Stress Relationship
Highly Accelerated Life Test(HALT) – Qualitative ALT1. Improve Reliability by FindingWeaknesses and CorrectingThem Early.2. Establish Upper and LowerOperating and Destruct Limits ofEnvironmental Stressors3. Typically done in Temperature &Vibration Chamber forElectronics & ElectromechanicalProducts4. Concept can be Applied to OtherStressors (Voltage, Current,Mechanical Loads, etc.)
Quantitative ALT Test to Failure at Multiple AcceleratedStress Levels Use Analysis to Extrapolate Reliability orLife at Application Use Level Stress Can be Used to Demonstrate Ability toMeet Reliability Requirements
Cautions on Acceleration Understanding product limits helps prevent acceleratingto unrepresentative stresses and failure modes Time– Consider Heat Buildup– Effects of Cycling Temperature– Material Phase transitions– Non-linear response– High temperature or thermal cycling? Power– Protective and limit devices– Transients Vibration– Mechanical limits or resonances What failure mechanism are we accelerating?
Data Collected Test Parameters Measured– Temperature, Power Density, Cycle Rate, Vibration,Humidity, Voltage, etc. applied– Product Response or Function (monitor during test) Time to Failure or Run Time (Suspended)– At least 3 Different Stress Levels– Fit Data Points to Appropriate Distribution Product Limits from Step Stress Test Failure Mode Observations
Data Analysis Analyze Data and Extrapolate Life at Use LevelStress Life-Stress Relationships (predictive models)––––Arrhenius – TemperatureEyring – Temperature or humidityInverse Power Law – Voltage, Power, MechanicalMultiple Life-Stress Models Temperature / HumidityTemperature / Non-Thermal: Temp / Voltage or PowerGeneral Log Linear: multiple accelerating stressesProportional Hazards: multiple covariatesCumulative Damage – Time varying stress profiles page
controlled to minimize product variation. There may be more than one process characteristic for each product characteristic. Product/Process Specifications/ Tolerance Specifications/tolerance may be obtained from various engineering documents, such as, but not limited to, drawings, design reviews, material standard, computer aided design data,
About Values Mapped from an FMEA Template to Asset Strategy Template 39 Save an FMEA Analysis as a Template 39 Access a Template 39. iii. Modify an FMEA Analysis14. Copy and Paste Nodes in an Analysis or Template14. Promote an FMEA Analysis to Strategy15. Export an FMEA Analysis16. Use State Controls in FMEA Analyses17. Delete an FMEA Analysis18
5.2 Advantages of the new Form VDA '96 31 6 Organisational sequences of a System FMEA 32 6.1 Drawing-up of System FMEA by Teamwork 32 6.2 Time sequence for the System FMEA 34 6.3 Co-operation during Execution 34 6.3.1 Design potential FMEA/Process potential FMEA 34 6.3.2 Design FMEA/Process
boundary diagram. The diagram is used at the start of each DFMEA in the AIAG approach. See an example of a block diagram below 5T’s FMEA Team Who needs to be on the team? FMEA Timing when is this due? FMEA Intent why are we here? FMEA Task what work need to be done? FMEA
FMEA Block Diagram, FMEA Interface Matrix, Parameter Diagram, and Process Flow Diagram. (3) Assemble the right team To have an FMEA success, people are the key. Research shows that some FMEA teams fail because of inadequate team composition. The FMEA facilitator needs to consider questions like: What kinds of experts should be on the team?
Make FMEA official part of the Phase-Gate Business Process Provide enough time to the Engineers for the FMEA sessions FMEA Team to Present Top 5 Risks to Management External training on FMEA and resulting Control Plans Limit Scope, separate X-FMEA where X U, D, P, . Be prepared and discuss details, it's not a brainstorm Make it result in a
If we use a substantive (e.g. FMEA), the software provides: (1) the modifiers, or the adjectives or the substantives acting as adjectives (e.g. Design FMEA, Economic-Based FMEA), (2) the nouns and verbs modified by the keyword (e.g. FMEA template), (3) verbs using the keyword used as
1993 Ford, Chrysler, and General Motor established the 1st edition FMEA reference manual 1995 The 2nd edition of FMEA reference manual was revised by AIAG 2001 The 3rd edition FMEA reference manual was revised by AIAG 2008 The 4th edition FMEA reference manual was revised by AIAG 2008-now FMEA is considered as an important examining item and .
the common mistakes that fail FMEA in define phase is to do an FMEA on an undocumented process. FMEA works on a single why for each failure mode and does not dig deeper. A better method would be to use 5 Why's and generate a Cause-Effect tree structure. b. Measure & Analyze: FMEA fails to identify the correct risk level because of the below .
