Current Control
Design and Process controls are grouped according to their Design and Process controls are grouped according to their purpose.
purpose.
Type (1):
Type (1): These controls prevenThese controls prevent the Cause or Failure t the Cause or Failure Mode from occurring, orMode from occurring, or reduce their rate of occurrence.
reduce their rate of occurrence.
Type Type (2):
(2):
These controls detect the Cause of the Failure Mode and lead to These controls detect the Cause of the Failure Mode and lead to corrective action.
These Controls detect the Failure Mode before the product reaches the These Controls detect the Failure Mode before the product reaches the customer. The customer could be the next operation, subsequent
customer. The customer could be the next operation, subsequent operations, or the end user.
operations, or the end user.
The distinction between controls that
The distinction between controls that prevent prevent failure (Type 1) and controls thatfailure (Type 1) and controls that detect detect failure (Types 2 and 3) is important. Type 1 controls reduce the likelihood that a Cause or failure (Types 2 and 3) is important. Type 1 controls reduce the likelihood that a Cause or Failure Mode will occur, and therefore affect Occurrence ratings. Type 2 and Type 3
Failure Mode will occur, and therefore affect Occurrence ratings. Type 2 and Type 3 Controls detect Causes and Failure Modes respectively, and therefore affect
Controls detect Causes and Failure Modes respectively, and therefore affect DetectionDetection ratings.
ratings.
Detection values are associated with Current Controls. Detection is a measurement of the Detection values are associated with Current Controls. Detection is a measurement of the ability of
ability of Type (2)Type (2) Controls to detect Causes or mechanisms of failure, or the ability of Controls to detect Causes or mechanisms of failure, or the ability of Type (3)
Type (3) Controls to detect subsequent Failure Modes. One Controls to detect subsequent Failure Modes. One Detection value is Detection value is assigned toassigned to the system of Current Controls, which represents a collective ability to detect Causes or the system of Current Controls, which represents a collective ability to detect Causes or Failure Modes. Controls can be grouped and treated as a system when they operate Failure Modes. Controls can be grouped and treated as a system when they operate independently, as
independently, as each each individindividual Control ual Control increases overall increases overall detection capabilitiedetection capabilities. s. TheThe design and process ranking systems presented in
design and process ranking systems presented in Table 5Table 5 andand Table 6Table 6 are based on AIAGare based on AIAG standards.
standards.
Notes of Interest:
Notes of Interest:
••High values indicate a lack of High values indicate a lack of detection ability.detection ability.
••The tables are not The tables are not quantitative; relative terms are used.quantitative; relative terms are used.
••The adjectives used to describe the likelihood of Detection indicate a generally linearThe adjectives used to describe the likelihood of Detection indicate a generally linear relationship.
relationship.
•• A Detection value of 1 A Detection value of 1 does not imply 100% detection.does not imply 100% detection.
Note:
Note: These tables differ These tables differ slightly from those published by slightly from those published by the AIAG. Specific references the AIAG. Specific references toto motor vehicles have been removed. The tables are similar to AIAG tables in that they are motor vehicles have been removed. The tables are similar to AIAG tables in that they are
D
Design Control does not detect a
Design Control does not detect a potential Cause of failure or subsequentpotential Cause of failure or subsequent Failure Mode; or there is no
Failure Mode; or there is no Design ControlDesign Control 1010 Very
Very Remote Remote
Very remote chance the Design
Very remote chance the Design Control will detect a potential Cause of Control will detect a potential Cause of failure or subsequent Failure Mode
failure or subsequent Failure Mode 99
Remote
Remote Remote chance the Design Control will Remote chance the Design Control will detect a potential Cause of failuredetect a potential Cause of failure or subsequent Failure Mode
or subsequent Failure Mode 88
Very Low
Very Low Very low chance the Design Very low chance the Design Control will detect a potential Cause of failureControl will detect a potential Cause of failure or subsequent Failure Mode
or subsequent Failure Mode 77
Low
Low Low chance the Design Low chance the Design Control will detect a potential Cause of failure orControl will detect a potential Cause of failure or subsequent Failure Mode
subsequent Failure Mode 66
Moderate
Moderate Moderate chance the Design Control will detect Moderate chance the Design Control will detect a potential Cause of a potential Cause of failure or subsequent Failure Mode
failure or subsequent Failure Mode 55
Moderatel Moderatel y High y High
Moderately high chance the Design Control
Moderately high chance the Design Control will detect a potential Cause of will detect a potential Cause of failure or subsequent Failure Mode
failure or subsequent Failure Mode 44
High
High High chance the Design High chance the Design Control will detect a potential Cause of failure orControl will detect a potential Cause of failure or subsequent Failure Mode
subsequent Failure Mode 33
Very High
Very High Very high chance the Very high chance the Design Control will detect a pDesign Control will detect a potential Cause of otential Cause of failure or subsequent Failure Mode
failure or subsequent Failure Mode 22
Almost Almost Certain Certain
Design Control will almost certainly detect a potential
Design Control will almost certainly detect a potential Cause of failure orCause of failure or subsequent Failure Mode
subsequent Failure Mode 11
Table 5.
Table 5. Suggested evaluation criteria and ranking system for the Detection of a Cause of Suggested evaluation criteria and ranking system for the Detection of a Cause of failure orfailure or Failure Mode in a
Failure Mode in a design FMEA.design FMEA.
D
Very Remote Very remote likelihood current Controls with detect Failure Mode or Very remote likelihood current Controls with detect Failure Mode or Cause
Moderately high likelihood current Controls with detect Failure Mode or Moderately high likelihood current Controls with detect Failure Mode or Cause
Current Controls almost certain to Failure Mode or Cause. Reliable Current Controls almost certain to Failure Mode or Cause. Reliable detection controls are known with similar processes.
detection controls are known with similar processes. 11 Table 6.
Table 6. Suggested evaluation criteria and ranking system for the DSuggested evaluation criteria and ranking system for the Detection of aetection of a Cause of failure or Failure Mode in a process FMEA
Cause of failure or Failure Mode in a process FMEA