Definition
A failure mode is the specific way in which a component or function fails to meet its required performance: a bearing seizes, a valve fails to close, a seal leaks. It describes the observable manner of failure, the building block FMEA uses to systematically list every way a function could fail before assessing causes and effects.
Key facts
- Describes the observable manner of failure (seizes, leaks, fails to close), not the underlying cause or the resulting consequence.
- The core unit FMEA enumerates: for each function, every plausible way it could fail to perform.
- One failure cause or mechanism can produce different failure modes depending on component and context.
- Distinct from functional failure, which is the broader state of not meeting a required function: failure mode is the specific manner in which that state occurs.
What does Failure mode reveal about failures?
A failure mode describes the specific, observable way a component or function stops performing as required (for example, a valve failing to open, a bearing seizing, or a seal beginning to leak) the concrete manner of failure that FMEA lists systematically for each function under review.
How do teams use Failure mode in failure analysis?
Functional failure is the broader state: the function is no longer met, regardless of manner. Failure mode is the specific way that state manifests. Failure cause explains why it happened at all: a failure mode ("seizes") can result from different causes (contamination, misalignment, lack of lubrication) depending on the situation.
FAQ
Frequently asked questions
In what way does a function actually fail?
The failure mode describes the specific, observable manner in which a function stops meeting its requirement (such as seizing, leaking, or failing to close) the unit FMEA lists systematically for each function analyzed.
Last reviewed: