Managing
technical uncertainties
Statistics,
RAMS
& Quality Management
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Common
Issues with FMEA
- The
more persons involved in a FMEA session, and
- the more degrees of
freedom allowed during the FMEA process,
the more
difficult the FMEA is
to handle, and the longer it takes until the FMEA team begins to take
momentum.
My experience
suggests the following:
Piece
Part FMEA
The most important factor is the FMEA experience of the hardware
developer. It takes typically between one hour and one day until the
developer feels comfortable to conduct piece part FMEAs on his own.
Undesired effects on system level are either a no-brainer, foreseeable,
can be derived from requirements specifications., or are just given by
the customer. Therefore there is a good chance that the developer
will be able to complete the FMEA without
forgetting substantial topics.
Additionally,
the hardware developer
is typically the only person with
thorough technical knowledge. In particular for electronic
systems, the ability of reading schematics limits the potential
participants for piece part FMEAs to a small number.
However, it
may be advantageous to
have more participants in the FMEA
process, especially if they have different insight, for
example a service technician, a customer engineer, or the senior of the
developer.
Independent
from the FMEA experience
of the developer, it is almost always a good idea to have an FMEA
moderator in the team.
If the developer is unexperienced, it is the moderator's job to teach
the developer until he feels comfortable with the FMEA process.
But a moderator can add value to the FMEA process even for experienced
developers by easing
the workload: The moderator can take all the paperwork and therefore
ensure FMEA consistency.
With a moderator participating
in a piece part FMEA, the developer can
settle back and concentrate on transforming his detailed knowledge into
FMEA content.
(Practical
experience shows that FMEA
paperwork (especially maintaining consistency) can sometimes be even
more work-intensive than
the work of the developer).
Taking into account FMEA preparation, conduction, evaluation and
reporting, circa 80% of the whole workload attribute to the FMEA
moderator, while only 20% attribute to the developer. The developer's
workload is basically the time spent during the FMEA
session.
The FMEA
moderator must fulfil the
following prerequisites in order to
make a good job:
- Understand the item on a general technical level.
- This enables the moderator to ask valid questions and to direct
the developer through the FMEA session.
- If not an electrical engineer, the moderator's education should
be
in some proximity to electrical engineering.
- Reading and understanding electrical schematics is a MUST
- With developers often being silent and introverted, the moderator
must encourage them to utter their thoughts.
- So called soft skills may help here, but this should not be
overstated. Experience shows that
understanding electrical schematics in conjunction with general
technical knowledge is by far the most important trait of the
moderator.
FMEAs
with many participants
In contrast to
piece part FMEAs, most
FMEAs are more general, with
participants coming from different departments.
Practical
experience suggests that
the maximum group size of the FMEA
team should not exceed 8. However, with disciplined and experienced
team members, groups of even 12 may be successful.
In some cases,
when companies ask for
FMEA consulting service,
participants not only come from different departments, but for some of
them it's even the first time being in the same meeting with their
fellows. This scenario
is the most difficult one a moderator could face. Some group members
may have difficulties in accepting alternative viewpoints, whereas
other members must learn that their knowledge is welcome and that they
are required to utter their thoughts. Therefore the FMEA moderator must
not
only combine different viewpoints and interests, he must also help the
group in becoming an efficient FMEA team.
Depending on
the company culture it
can be advantageous or
disadvantageous when staff members and their bosses share the same FMEA
meeting.
Typical groups
performing a general
FMEA look like this:
- 2 developers
- 2 production operators
- 1 service engineer
- 1 buyer
- 1 project manager
- 1 quality representative
Such FMEAs are
often not limited to a
single session. These so called FMEA processes are quite common in
automotive industry.
During product
development life
cycle, FMEA sessions will be repeated
at specific time points, and the FMEA worksheet will be used as a
tracking tool for improvement and mitigation actions. This is a so
called live FMEA process with a life FMEA worksheet.
Unfortunately
there are some issues
related with these FMEAs.
With
increasing FMEA team size,
increasing time intervals between FMEA
sessions, changing team members and increasing degrees of freedom of
the FMEA process, the following problems will almost certain appear:
- Inconsistency
- Inconsistent FMEA methodology
- Causes identified in the latest FMEA session may be conceived
as failure modes in the current session, and in the next session the
same
things may appear as effects, or vice versa. While this can be correct
from a technical viewpoint, it is strongly recommended to keep topics
on the same level throughout the FMEA process. If not, FMEA evaluation
(e.g. FMEA summary) could become difficult or even impossible, and if
the worst comes to the worst, contradictory FMEA content could
occur.
- Inconsistent wording
- Different wordings for similar or even identical topics, or
identical wording for different topics. It is strongly recommended to
fill the FMEA with standardized text modules, at least for some data
field types. It takes some time to realize for which data fields text
modules make sense and for which not, and it takes at least 2 or 3
FMEAs to establish a reasonable set of text modules.
- FMEA Process peters out, falls asleep
- FMEA sessions tend to be time consuming. Furthermore it is
difficult to have all necessary team members available at the same
time. As a consequence, companies tend to postpone necessary FMEA
sessions until an interested party (customer) explicitly requests an
FMEA. Then however, it could be too late because improvement actions
potentially identified in the FMEA take much time.
While the
first problem
(inconsistency) suggests the use of dedicated
FMEA software instead of a spread sheet, the second problem is a
perfect justification for having an FMEA moderator being responsible
for the FMEA process. FMEA moderators are usually located in the
quality management department.
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