Page 432 - Design for Six Sigma a Roadmap for Product Development

396 Chapter Eleven

TABLE 11.3 Automotive Industry Action Group (AIAG) Detection Rating

Detection Likelihood of detection Rating
Almost certain Design control will almost certainly detect a potential 1
cause/mechanism and subsequent failure mode
Very high Very high chance design control will detect a potential 2
cause/mechanism and subsequent failure mode
High High chance design control will detect a potential 3
cause/mechanism and subsequent failure mode
Moderately high Moderately high chance design control will detect a 4
potential cause/mechanism and subsequent failure mode
Moderate Moderate chance design control will detect a potential 5
cause/mechanism and subsequent failure mode
Low Low chance design control will detect a potential cause/ 6
mechanism and subsequent failure mode
Very low Very low chance design control will detect a potential 7
cause/mechanism and subsequent failure mode
Remote Remote chance design control will detect a potential 8
cause/mechanism and subsequent failure mode
Very remote Very remote chance design control will detect a potential 9
cause/mechanism and subsequent failure mode
Absolute Design control will not and/or cannot detect a potential 10
uncertainty cause/mechanism and subsequent failure mode; or
there is no design control

RPN numbers are used to prioritize the potential failures. The severity,
occurrence, and detection ratings are industry-specific and black belts
should use their own company-adopted rating systems. Automotive
industry ratings are summarized in Tables 11.1 to 11.3 (compiled AIAG
ratings are shown in Table 11.4). The software FMEA is given in
Table 11.5, while service FMEA ratings are given in Table 11.6.
10. Actions recommended. The DFSS team should select and man-
age recommended subsequent actions. That is where the risk of poten-
tial failures is high; an immediate control plan should be crafted to
control the situation.
Over the course of the design project, the DFSS team should
observe, learn, and update the FMEA as a dynamic living document.
FMEA is not retrospective, but a rich source of information for corpo-
rate memory, including core design books. The DFSS team should doc-
ument the FMEA and store it in a widely acceptable format in the
company in both electronic and physical media.

11.3 Design FMEA (DFMEA)
The objective of DFMEA is to help the team design for Six Sigma by
designing the failure modes out of their project. Ultimately, this objective