Understanding Failure Mode & Effect Analysis (FMEA)
Failure Mode & Effect Analysis (FMEA) is a structured method to recognize, evaluate, and mitigate potential failures in product/process design, manufacturing, and problem-solving. It helps prioritize actions to reduce the risk of failures and improve quality and reliability. FMEA is utilized in various industries to address potential failure modes and their effects systematically.
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INCOSE Michigan May Dinner Meeting Failure Mode & Effect Analysis (FMEA) in Half the Time Howard C Cooper, MS, DFSS-BB May 13th, 2014
Introduction Failure Mode & Effects Analysis (FMEA) is an analytical tool and structured method to: Recognize and evaluate the potential failure of a product/process and its effects Identify and prioritize actions which could eliminate or reduce the chance of a potential failure Document the process Before they are baked into a product 2 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Common Types of FMEA Design FMEA Identify and mitigate potential design problems early in the design cycle Process / Manufacturing FMEA Improve quality and reliability, during set-up of initial manufacturing process Problem Solving / Six Sigma FMEA Understand failure modes and effects to identify and solve quality or reliability issues 3 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Where FMEA is Used Common FMEA Usage Mfg: Work Product Definition: Key product characterist ics, Design FMEA Process Failure Mode Analysis: Process FMEA Process Definition: Process Flow Diagram (PFD) Control Strategy: Control Plan, Error proofing Customer Reqmts: Vehicle Tech Specs Instructions & Process Monitoring Six Sigma FMEA 4 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Prioritize Failure Modes by Risk Priority Number Example Design FMEA SEV X OCC X DET = (RPN) (physical or chemical processes, design defects, quality defects, part misapplication , or other). DFMEA FM Problem Report # Prevention Design Controls J1739 Field Failure Detection Method 1629a DVP&R Detection J1739 Failure Cause Item Local Effect Mode Next Level Up Effect On Vehicle Mission Soldier(s) SEV OCC DET RPN (What Failed) locked up, or open output driver 1.No provisioning of power for vehicle start up MRF = 1 - Combat Mission Failure on 100% of combat missions. [System Abort (SA)] Severity HALT tests EMI CS-101 & MIL- STD-1275 Suseptability Testing MIL-STD-810g Environmental Life Test Relative Occurrence PLCM Trip Status Reporting PLCM Pass/ Fail Reprting 43v Transients Clamps on all power supply inputs. MIL-STD-1275 Compliant Relay drivers and other higher current loads have transient protectoin. 5 degree C Thermal Margin on PLCMs Root Cause SPR- 00004339 Load Controller 5 3 3 45 FM & Effects of each failure mode 1. Over Voltage, 2. Voltage Transients PLCM Fault indicated 2. No distribution of power to hull and turret systems (SA Example; Generator Controller Dead) MRF = 1 - Combat Mission Failure on 100% of combat missions. [System Abort (SA)] HALT tests EMI CS-101 & MIL- STD-1275 Suseptability Testing MIL-STD-810g Environmental Life Test PLCM Trip Status Reporting PLCM Pass/ Fail Reprting 43v Transients Clamps on all power supply inputs. MIL-STD-1275 Compliant Relay drivers and other higher current loads have transient protectoin. 5 degree C Thermal Margin on PLCMs Transients Clamps on all power supply inputs. MIL- STD-1275 Compliant Relay drivers and other higher current loads have transient protectoin. 5 degree C Thermal Margin on PLCMs Transients Clamps on all power supply inputs. MIL- STD-1275 Compliant Relay drivers and other higher current loads have transient protectoin. SPR- 00004339 Load Controller 5 3 3 45 1. Over Voltage 2. Voltage Transients PLCM Fault indicated 1.No provisioning of power to vehicle start up MRF = 1 - Combat Mission Failure on 100% of combat missions. [System Abort (SA)] HALT tests EMI CS-101 & MIL- STD-1275 Suseptability Testing MIL-STD-810g Environmental Life Test SPR- 00004200 PDCM Trip Status Reporting PDCM Pass/ Fail Reprting Items within the system being analyzed Load Controller 5 3 3 45 1. Over Voltage 2. Voltage Transients ePDCM Failure 2. No distribution of power to hull and turret systems MRF = 1 - Combat Mission Failure on 100% of combat missions. [System Abort (SA)] SPR- 00004200 HALT tests EMI CS-101 & MIL- STD-1275 Suseptability Testing 1. Over Voltage 2. Voltage Transients PDCM BIT Pass/ Fail Reporting Control Module 5 2 3 30 5 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Example Process FMEA Item Potential Effect(s) of Failure Potential Occur Detec RPN Sev Process Function Potential Failure Mode Cause(s)/Mechanism(s) of Failure 3 - Front Door L.H. 5 Manually inserted spray head not inserted far enough. Current Process Controls Detection Manual application of chromate conversion coatings on exposed aluminum substrate (to retard corrosion) Insufficient chromate coating over specified surface. Deteriorated life of part leading to: - Unsatisfactory appearance due to rust through paint over time. - Impaired function of hardware. 3 Visual check each hour - 1/shift for film thickness (depth meter) and coverage. 5 75 Spray head clogged - Viscosity too high - Temperature too low - Pressure too low. 2 Visual check each hour - 1/shift for film thickness (depth meter) and coverage. 3 30 Spray head deformed due to impact. 2 Visual check each hour - 1/shift for film thickness (depth meter) and coverage. 2 20 Spray time insufficient. 1 Operator instructions and lot sampling (10 doors/shift) to check for coverage of critical areas. 2 10 Steps within the process being analyzed 6 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Typical FMEA Process 1. Assemble team of people with diverse knowledge of process & product 2. Bound the problem 3. Identify functions 4. Identify potential failure modes 5. Populate FMEA details 6. Prioritize failure modes based on RPN 7. Mitigate failure modes 7 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Mission to Improve FMEA Development Challenge Opportunity: Current FMEA problems: Time consuming Rapid (> 2x faster) High rate of missed critical failure modes Critical failure modes are given top-priority Ad hoc identification of failure modes Disjointed, undirected time- consuming discussion Process-driven identification of all failure modes Focused, efficient development effort Allows prioritization only after FMEA development Prioritization can happen before FMEA development 8 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Improved FMEA Process In 2012, GDLS developed process to prepare efficient and effective FMEA at greatly reduced time and cost Process involves four primary tools: Block / Process Diagram Decomposition Table p-Diagram FMEA Major innovation: Decomposition Table identifies and prioritizes Failure Modes (FMs) into FMEA. Focuses analysis on critical failure modes 9 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 1: Bound the System Boundary Diagram / Process Flow What Vehicle Structure Mount Exhaust Brake (valve) Seal / Flat Flange Engine Muffler Exhaust Pipe V- Flex Pipe V- Elbow 90 V- V- Exhaust Out Band Band Band Band Mount Insulation Vehicle Structure Identifies and verifies: 1. System functions: lines crossing the dotted boundary 2. Items within the dotted line system boundary 10 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 2: Characterize the Process What (From Boundary Diagram) P-Diagram Why Green blocks, identify functions of the system (or process) Yellow blocks ~ Noise Factors, Blue block, Control Factors, Pink blocks ~ Error States 11 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Outstanding Problem & Opportunity Boundary or Process Flow Diagram Identifies Items for the FMEA, but not the Failure Modes (FM) of those items P-Diagram Identifies system functions or requirements (even noise factors) but not the function or FMs of the items Opportunity Develop a table that will identify and link items to their functions, and to their functional FMs 12 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing P-Diagram 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Partially Restrict Exhaust Contain Exhaust Hardware Functions: Attenuate NVH Provide Flow Contain Heat Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow X Boundary / Process Diagram X X X X X X X X X X X X X X X X X X 13 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing P-Diagram 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Partially Restrict Exhaust Contain Exhaust Need to Identify Item / HW Functions Hardware Functions: Attenuate NVH Provide Flow Contain Heat Secure Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow X X Boundary / Process Diagram X X X X X X X X X X X X X X X X X X X X 14 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing P-Diagram 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Partially Restrict Exhaust Contain Exhaust Hardware Functions: Attenuate NVH Provide Flow Contain Heat Identify Functions Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow X Boundary / Process Diagram X X X X X X X X X X X X X X X X X X 15 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing P-Diagram 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Partially Restrict Exhaust Contain Exhaust Hardware Functions: Attenuate NVH Provide Flow Contain Heat Identify Functions Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow X Boundary / Process Diagram X X X X X X X X X X X X X X X X X X 16 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 3: Map Functions to Failure Modes Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing P-Diagram 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Partially Restrict Exhaust Contain Exhaust Hardware Functions: Attenuate NVH Provide Flow Contain Heat Identify Functions Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow X Boundary / Process Diagram X X X X X X X X X X X X X X X X X X 17 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Decomposition Table Structures FMEA Function to Hardware Decomposition Table System Functions "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH functions translate to FMs Partially Restrict Exhaust Contain Exhaust Hardware Functions: Attenuate NVH Provide Flow Contain Heat 3-4 FMs per Function Secure Hardware: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow From X B-Diagram or Pr-Flow Chart X X X X X X X X X X X indicates a Function (and 4 FMs in the FMEA) X X X X X X X X 18 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
3 Purposes of the Decomposition Table Ensures all items are captured into the FMEA Ensures multiple function items and their potential failure modes are identified into the FMEA Provides opportunity to identify and prioritize by criticality of hardware or process functions before populating failure modes into the FMEA 19 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Decomposition Table Prioritizes Functions Function to Hardware Decomposition Table (with Maximum Criticality Scored) System "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Likelyhood of Failure: 1 - 5 Contain Exhaust Restrict Exhaust Attenuate NVH Provide Flow Contain Heat Hardware Functions: Secure Hardware: Severity: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow 3 15 5 3 3 3 3 5 2 2 2 4 1 3 2 2 1 10 6 Criticality # rather than X 6 10 20 12 12 3 9 3 9 10 10 5 6 6 3 6 20 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Preparation Flow into Decomp Table Function to Hardware Decomposition Table (with Maximum Criticality Scored) "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) System 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Likelyhood of Failure: 1 - 5 Contain Exhaust Restrict Exhaust Attenuate NVH Provide Flow Contain Heat Hardware Functions: Secure 1. P-Diagram Ideal Functions to Design Functions in F-H Decomp. Hardware: Severity: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow 3 15 5 3 3 3 3 5 2 2 2 4 1 3 2 2 1 10 6 6 10 20 Vehicle Structure 12 12 3 9 3 Mount 9 10 10 5 6 6 3 6 Exhaust Brake (valve) Seal / Flat Flange Engine Muffler Exhaust Pipe V- Flex Pipe V- Elbow 90 V- V- Exhaust Out Band Band Band Band Mount Insulation 3. Identify all Item Functions needed to accomplish each System Function Vehicle Structure 2. B-Diagram or Process Flow inner blocks go to Decomp. Table 4. Mark with an X or with a Criticality # 21 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Step 4: Use Decomp Table to Fill FMEA Function to Hardware Decomposition Table (with Maximum Criticality Scored) 1 "Design" Functions: (Ideal Functions from P- Diagram / Functions (lines crossing boundary of B-Diagram "Design".) System 3. Limited thermal transfer to vehicle 5. Exhaust Brake Engine Slowing 1. Transfer Exaust from Engine out of the Vehicle 2. Attenuate NVH Likelyhood of Failure: 1 - 5 1 Contain Exhaust Restrict Exhaust Attenuate NVH 3 3 Provide Flow Contain Heat Hardware Functions: 1 Secure Hardware: Severity: V-Band Clamps Exaust Pipe Flat Flange Seals Muffler Insulation Isolation Mounts Exaust Brake Flex Pipe Elbow 3 15 5 3 3 3 3 4 2 2 5 2 2 2 4 1 3 2 2 1 10 6 6 10 20 12 12 3 9 3 9 10 10 5 6 6 3 6 1 Function 4 Local Effect Next Level Up Effect 2 3 (measurable output, design requirement) Item Potential Failure Mode Exhaust leak Loss of 1. Transfering Exhaust from Engine to out-side the Vehicle 1. Transfer Exaust from Engine out of the Vehicle V-Band Clamps Loss of Securing Partial Securing Intermittent Securing FMEA filled in from F-H Decomp Table 22 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Benefits of Improved FMEA Development Pareto Chart (80/20 Rule) Four Step FMEA Process: Organizes and speeds FMEA failure mode identification Ensures all hardware-functions and FMs are identified Prioritizes critical hardware-functions for FMEA analysis Provides power of 80/20 Rule on FMs for best Reliability Growth Focuses attention and time on mitigation of significant few (the most critical failure modes (FMs) F-H Decomp Table now being used on multiple GDLS Contracts: for DFR, to facilitate earlier diagnostics planning, to meet Weight and Testability Requirements Addressing most critical FMs yields greatest reliability growth. 23 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Cost Savings Attributed to New Process Before vs, After Facilitator Cost Savings Calculation Previous Programs doing DFMEA without 'F-H Decomp' Start SFR End PDR FCS 01-Mar-06 15-Dec-09 Stryker-SMOD 01-Jan-10 15-Dec-10 Average: (savings to GDLS) Weeks 185 50 117.5 Rel-Heads Hrs/Week Total Hrs. $Rate/Hr. 3 35 4 35 3.5 Total $ $1,495,725 $539,000 $1,017,363 19,425 7,000 $77 $77 Average: Savings on Facilitator Cost 2013 Programs using 'F-H Docomp Tool/Method' for DFMEA Start SFR End PDR Weeks Stryker+Tr 16-Oct-12 15-Mar-13 Stryker-ECP 01-Oct-12 27-Sep-13 Abrams ECP1 04-Feb-13 14-Aug-13 Average: 32.43 Rel-Heads Hrs/Week Total Hrs. $Rate/Hr. 1 35 0.65 35 1 35 0.88 Total $ $53,900 $87,588 $73,574 $71,687 20 50 27.3 700 1,138 956 931 $77 $77 $77 $77 Facilitator Savings X 3 for FMEA Team, X 3 Programs in 2013 = Total Savings Savings $1,424,038 Savings over FCS - DFMEA Facilitator $467,313 Savings over SMOD - DFMEA Facilitator $945,676 Savings over FCS & SMOD Average, for DFMEA Facilitator X3 Facilitator labor Savings over SMOD baseline, for DFMEA Team (3-8) $1,401,939 Average 2013 FH-Decomp Program Savings over SMOD baseline - DFMEA Cost X3 Three 2013 Programs: Stryker+Tr, Stryker-ECP and Abrams ECP1 $4,205,817 Total 2013 Savings from using FH-Decomp to prepare DFMEA 24 Approved for Public Release, Distribution Unlimited, LogNo. 2014-07, 26 FEB 14
Questions? Presenters: Howard C Cooper, MS, DFSS-BB DFR Reliability Engineer cooperh@gdls.com Mark Petrotta, MS, DFSS-MBB Engineering Process Excellence petrotta@gdls.com 25
