FMEA Failure Mode Effect Analysis
This past week during our Extreme Plant Makeover assignment the organization was presented with a huge potential opportunity to expand their business. Tons of meetings and discussions have been held to determine capability and viability of the accepting the challenge ... But the President was getting tired that the meetings were not resulting in any traction. Plus the customer needed confirmation that the transition could be done seamlessly since the project would include the transfer of some critical equipment.
As I mentioned to the team that we needed to complete a FEMA exercise ... I just got a bunch of dumb looks. FEMA is a powerful tool and should be employed whenever a significant new project or process is being introduced.
The FMEA is not a new tool. The aerospace industry used the FMEA during the Apollo missions in the 1960s. Later in 1974 the US Navy developed MIL-STD-1629 which discussed the proper use of the tool. And around this time the automotive folks latched onto the tool and never let go. Today, the FMEA is universally used by many different industries.
Types of FMEA
There are three main types of FMEA in use today.
System FMEA: Used to analyze complete systems and/or sub-systems during the concept of design stage.
Design FMEA: Used the analyze a product design before it is released to manufacturing. Process | Project FMEA: Used to analyze manufacturing and/or assembly process.
The Process FMEA is probably the most commonly used and is also the least complex, in most cases.
10 steps to creating a FMEA
List the key process steps in the first column. These may come from the highest ranked items of your C&E matrix.
List the potential failure mode for each process step. In other words, figure out how this process step or input could go wrong.
List the effects of this failure mode. If the failure mode occurs what does this mean to us and our customer… in short what is the effect?
Rate how severe this effect is with 1 being not severe at all and 10 being extremely severe. Ensure the team understands and agrees to the scale before you start. Also, make this ranking system “your own” and don’t bother trying to copy it out of a book.
Identify the causes of the failure mode/effect and rank it as you did the effects in the occurence column. This time, as the name implies, we are scoring how likely this cause will occur. So, 1 means it is highly unlikely to ever occur and 10 means we expect it to happen all the time.
Identify the controls in place to detect the issue and rank its effectiveness in the detection column. Here a score of 1 would mean we have excellent controls and 10 would mean we have no controls or extremely weak controls. If a SOP is noted here (a weak control in my opinion) you should note the SOP number.
Multiply the severity, occurrence, and detection numbers and store this value in the RPN (risk priority number) column. This is the key number that will be used to identify where the team should focus first. If, for example, we had a severity of 10 (very severe), occurrence of 10 (happens all the time), and detection of 10 (cannot detect it) our RPN is 1000. This means all hands on deck… we have a serious issue!
Sort by RPN number and identify most critical issues. The team must decide where to focus first.
Assign specific actions with responsible persons. Also, be sure to include the date for when this action is expected to be complete.
Once actions have been completed, re-score the occurrence and detection. In most cases we will not change the severity score unless the customer decides this is not an important issue.
The single biggest failure people make with FMEAs is to spend time completing the document and then storing it in a file cabinet somewhere. The FMEA is the ultimate dynamic document meaning it lives as long as the process or product it is associated with does. Please use them!