FMEA
Description:
Failure
Mode and Effects Analysis (FMEA) is a model used to prioritize
potential defects based on their severity, expected frequency, and
likelihood of detection.
When to Use:
- An FMEA can be used on a design or a process, and is used to prompt actions to improve design or process robustness.
-
The FMEA highlights weaknesses in the current design or process in
terms of the customer, and is an excellent vehicle to prioritize and
organize continuous improvement efforts on areas which offer the
greatest return.
Construction :
1- The process is very straightforward, and begins by identifying all of the probable failure modes.
2- This analysis is based on experience, review, and brainstorming, and should use actual data if possible.
3-
New designs or processes may not have actual historical data to draw
from, but "proxy" data may be available from similar designs or
processes.
4- The next step is to assign a value on a 1-10 scale
for the severity, probability of occurrence, and probability of
detection for each of the potential failure modes.
5- After
assigning a value, the three numbers for each failure mode are
multiplied together to yield a Risk Priority Number (RPN). The RPN
becomes a priority value to rank the failure modes, with the highest
number demanding the most urgent improvement activity.
6- Error-proofing, or poka-yoke actions are often an effective response to high RPN's.
Following is an example of a simplified FMEA for a seat belt installation process at an automobile assembly plant. 
As you can see, three potential failure modes have been identified.
Failure mode number two has an RPN of 144, and is therefore the highest priority for process improvement.
FMEA's are often completed as part of a new product launch process.
RPN minimum targets may be established to ensure a given level of process capability before shipping product to customers.
In
that event, it is wise to establish guidelines for assessing the values
for Severity, Occurrence, and Detection to make the RPN as objective as
