Il citez pe colegul meu cu 40 de ani de experienta: "If you don't have time, do an FMEA!", referindu-se la deadline-urile presante din proiecte, cand trebuie sa alegi doar o metoda de safety analysis.
Notitele mele:
FMEA= Failure Mode and Effect Analysis
It is a systematic method for identifying and preventing product and process problems before they occur.
...defect prevention rather than defect detection.
The objective of FMEA is to look for all of the ways a process or product can fail. A product failure occurs when the product does not function as it should or when it malfunctions in some way.
Ways in which a product or process can fail are called failure modes. Each failure mode has a potential effect. Each potential effect has a relative risk. FMEA is a way to identify the failures, effects, and risks within a process or product, and then eliminate or reduce them.
The relative risk is determined by three factors: Severity, Occurence and Detection. They have a scale from 1 to 10, low to high.
By multiplying the rating for the three factors (S X O X D), a Risk Priority Number (RPN) is determined.
Failure modes with the highest RPNs should be attended to first, special attention should be given when the severity rating is high (9 or 10) regardless of the RPN.
Once corrective action has been taken, a new RPN is calculated, called the Resulting RPN.
Personal egos should not get in the way of FMEA.
Product/Design FMEA (dFMEA) has the objective to uncover problems with the product that will result in safety hazards, product malfunctions, or shortened product life.
Process FMEA (pFMEA) uncovers process problems related to the manufacture of the product.
The 10 steps of FMEAs:
Step 1: Review the FMEA process.
Step 2: Brainstorm protential failure modes.
Step 3: List potential effects of each failure mode.
Step 4: Assign a severity rating for each effect.
Step 5: Assign an occurence rating for each failure mode.
Step 6: Assign a detection rating for each failure mode and/or effect.
Step 7: Calculate the RPN for each effect.
Step 8: Prioritize the failure modes for action.
Step 9: Take action to eliminate or reduce the high-risk failure modes.
Step 10: Calculate the resulting RPN as the failure modes are reduced or eliminated.
FMEA template page 29.
For severity: because each failure may have several different effects, and each effect can have a different level of severity, it is the effect, not the failure, that is rated.
Break the product into manageable chunks (into key components).
The severity factor is the most difficult to reduce, usually the occurance is reduced through mistake-proofing techniques, or detection is improved.