Failure Modes and Effects Analysis (FMEA). Description. Failure modes and effects analysis (FMEA) is a step-by-step approach for identifying all possible failures in a design, a manufacturing or assembly process, or a product or service.
for identifying all possible failures in a design, a manufacturing or
assembly process, or a product or service.
fail. Failures are any errors or defects, especially ones that affect the
customer, and can be potential or actual.
by the US Armed Forces.
in small sample sizes of costly rocket technology.
automotive industry for safety and regulatory consideration after the
Pintoaffair. They also used it to improve production and design.
about the Design, process, product or service and customer needs.
product/process should be developed. This diagram shows major
components or process steps as blocks connected together by lines that
indicate how the components or steps are related.
components, list them in a logical manner under their subsystem/assembly based on
the block diagram.
component, subsystem, system, process, etc. could potentially fail to meet the design
intent. Examples of potential failure modes include:
related systems, process, related processes, product, service,
customer or regulations.
Severity is usually rated on a scale from 1 to 10, where 1 is insignificant
and 10 is catastrophic. Examples of failure effects include:
possible causes for each failure mode on the FMEA form.
estimates the probability of failure occurring for that reason during the
lifetime of your scope. Occurrence is usually rated on a scale from 1 to 10.
procedures or mechanisms that you now have in place to keep failures
from reaching the customer.
likelihood that the Current Controls (design and process) will detect the
Cause of the Failure Mode or the Failure Mode itself, thus preventing it
from reaching the Customer.
mathematical product of the numerical Severity, Probability, and
RPN = (Severity) x (Probability) x (Detection)
changes to lower severity or occurrence. They may be additional
controls to improve detection. Also note who is responsible for the
actions and target completion dates.
changes or new information becomes known.
Design-FMEA or process
DFMEA- Procedure or process
1: Review the Design
Reasons for the review:
2. Brainstorm Potential Failure Modes or process
Consider potential failure modes for each component and interface.
Prepare for the brainstorming activity.
3. List Potential Effects of Failure or process
4. Assign Severity Rankings
5. Assign Occurrence Rankings or process
6. Assign Detection Rankings
design controls to prevent or detect the mechanism of failure.
7. Calculate the RPN or process
8. Develop the Action Plan
There are many tools to aid the DFMEA team in reducing the relative risk of those failure modes requiring action
Mistake-Proofing (Poka Yoke)
9. Take Action
10. Recalculate the Resulting RPN (DFA/DFM)