1. FMEA

2. Failure Mode & Effects Analysis
Tool to identify & characterize potential failures
Can be used for product or process
Example: Self cleaning feature on Thermador oven

3. Step 1 Identify parts w.r.t. related function Example:
Screw – fasten part A to part B
Shaft – rotate part C

4. Step 2 Identify Potential Failure Modes Example Part Pot. Failure Mode
Screw
loose, stripped thread, damaged head, corroded
Shaft
bent, scored, fractured, seized, worn, excessive vibration

5. Step 2 Consider how function of part transforms/ transfers Look at:
Matter
Energy
Information
Look at:
Engineering specs
Functional decomposition
Detail/assembly drawings
Test results

6. Examples of Failure Modes
Mechanical
Fracture (break)
Buckle (local or general)
Bend / distort
Plastic deformation
Bind / seize
Vibrate / resonate
Delaminate
Wear / Galling / Fretting
Corrode
Electrical
Short circuit / low resistance
Open circuit / high resistance
Chemical
Thermal

7. Step 3
Identify the potential effect of the failure mode and rank it’s SEVERITY

8. Severity

9. Step 4 Determine possible / potential causes of each failure mode
Excessive Vibration
High unbalance
Low stiffness
Operation at resonance
Low damping
High damping
Excessive Wear
High speed
High load
Inappropriate material pair
Misalignment

10. Step 5
Estimate the likelihood / probability of OCCURRENCE

11. Probability

12. Step 6
Identify design activities / controls / testing procedures to validate the design or detect defects in design or manufacturing

13. Step 7
Estimate the likelihood that the control actions taken in Step 6 will DETECT each cause of failure

14. Detectability

15. Step 8
Calculate the Risk Priority Number for each failure mode
RPN = (S)(O)(D)

16. Step 9
Construct recommendations
Take actions

17. Step 10
After implementing changes, reassess the Severity, Occurrence, and Detectability.
Recalculate the RPN

18. Troubleshoot a High RPN
Severity is high
Product redesign is likely to be required
Probability is high
Focus on control actions
Defect rate is high
Implement better testing, or redesign to prevent / reduce defect occurring