FMEA失效模式及其影响分析.ppt

文档介绍：FMEA失效模式及其影响分析
由NordriDesign提供

NASA used FMEA to identify Single Point Failures on Apollo prore listed under current controls.
Detection The effectiveness of each current control method is rated on a
provided scale from 1 to 10. A 10 implies the control will not detect
the presence of a failure; a 1 suggests detection is nearly certain.
Process Failure Mode
The potential failure mode is the manner in which the process could fail to perform its intended function.
The failure mode for a particular operation could be a cause in a subsequent (downstream) operation or an effect associated with a potential failure in a previous (upstream) operation.
FAILURE
MODE
EFFECT
PREVIOUS
OPERATION
CAUSE
NEXT
OPERATION
Process Causes
Process FMEA considers process variability due to:
OPERATOR
SET-UP
MACHINE
METHOD
ENVIRONMENT
MEASUREMENT
Current Controls
Assessment of the ability of the control to detect the failure before the item leaves the manufacturing area and ships to the customer.
Capability of all controls in the process to prevent escapes
SPC
Process Capability
Gage R&R
Sampling
Testing
DOE
Types of Measures
SEVERITY
As it applies to the effects on the local system, next level, and end user
OCCURRENCE
Likelihood that a specific cause will occur and result in a specific failure mode
DETECTION
Ability of the current / proposed control mechanism to detect and identify the failure mode
Typically, three items are scored:
Risk Priority Number
RPN = O x S x D
Occurrence x
Severity x
Detection
O
S
D
x
x
= RPN
Shortcomings of RPN
A 8 4 3 96
B 4 8 3 96
SAME RESULT
Failure Mode
Severity
Occurrence
Effectiveness
RPN
Severity
Occurance
Detection
It is conducted on a timely basis
and

It is applied by a product team
and
Its results are documented