FMEA stands for Failure Mode Effects and Analysis.
You will find many people using this term and everyone gets impressed. Some of us may not immediately understand. But don’t worry this is very simple concept.
Lets take example : we have called some guests in the evening for dinner. Wife started cooking food and as always I was trying to help her out with whatever possible work. Being from manufacturing I was trying to show my expertise. Wife asked me if you are so expert can you ensure that food is really nice and no mistake is done.
Following is my analysis and implementation for ensuring nicely cooked food.
Very first step make a Process Flow Diagram. For every product, there will be separate PFD. Lets take example of rice.
Process Flow Diagram for Rice.
1. Take correct quantity of rice.
2. Clean it.
3. Rinse it.
4. Put it in a proper container and add sufficient water.
5. Put it in a Pressure cooker.
6. After 3 whistles put the gas on seam.
7. Wait for 10 minutes and shut it off.
8. Open pressure cooker after some time and rice is ready for serving.
Now next step if to make PFMEA, as it is Process FMEA, we call it PFMEA if done for Design it is called as DFMEA.
PFMEA: Now again going back to my wife’s question, can you assure everything will be ok? Now how to ensure this.
1. First read above PFD step by step and analyse following three factors.
A. What can go wrong?
B. How bad is the impact of this something going wrong?
C. Is there any present interlock to detect if something is going wrong?
Lets take example of our first step of PFD ie Take correct quantity of rice.
A. What can go wrong?
1. Correct quantity is not taken. : Preventive action for eliminating this mistake, I’ve counted the number of guests and with assumption of 50gms for each guest, took 500 gms of rice.
B. How bad is the impact?
1. Quantity is more, may go waste or you can enjoy in next days breakfast: Medium risk
2. Quantity is less: Some guests may not get rice in dinner. : High Risk.
C. Is there any existing interlock to prevent this: Yes we have a utensil marked with grams and can prevent less or more quantity. : This interlock is mitigating the risk involved.
Now these A, B and C factors needs to be ranked on scale of 1-10 (steps of 1-3-6-9). Then multiply to derive a number which is called as RPN (Risk Priority Number).
Then arrange these RPN’s in descending order and attack only top 20% or so items. With this your process will become robust.
Now you can see for details an image downloaded from google for formats etc.
See how simple is FMEA…