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Crystal Ball Provides
Quality Insights to Six Sigma Consultant Andell Associates
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Jonathon Andell is President of Andell Associates,
an independent consulting firm specializing in the technical, organizational,
and interpersonal aspects of modern Quality Management. One of the
earliest certified Six Sigma Black Belts, Andell has written extensively
on statistical methodologies, quality management, and the business
ramifications of Six Sigma. For Andell Associates, Crystal Ball
is a significant weapon in their substantial arsenal against process
and product variation.
A Crystal Ball user since 1993, Andell related an
early application of the software. "I was working for an electronics
assembly house that used a robot to mount integrated circuit (IC)
devices onto printed wiring boards (PWBs). Each device lead had
to penetrate a mating hole in the PWB. Andell and his colleagues
were struggling to establish specification limits for component
geometries and for placement equipment. Up to that time, the complex
two-dimensional geometries made it difficult to predict how variation
would propagate. For example, placement machines had target X-axis
and Y-axis locations, along with rotational orientations (called
the 
axis)." Andell and his colleagues could model how a single combination
of X, Y, and
errors would impact whether a pin could penetrate its mating hole,
but they lacked the ability to know how distributions of X, Y, and
would
stack up.
Andell and his colleagues addressed this uncertainty
by developing an Excel spreadsheet model that computed the clearance
(the output, or "dependent variable") based on part dimensions,
pin diameters, and hole diameters, as well as placement errors in
two horizontal axes (X and Y) and one rotational one ().
Collectively these inputs were called the "independent variables."
The analysis consisted of using statistical Design of Experiments
(DoE) to dictate settings for the mean and standard deviation of
each independent variable.
Once the distributions of the independent variables
had been defined, the team used Crystal Ball to simulate 1,000 trials
for each experimental run, which in turn yielded the probability
of all leads penetrating their mating holes on the first attempt.
The higher the probability, the more closely they could approach
the "six sigma" objective. As a result of the simulation, they were
able to establish tolerances for component geometries and for placement
capabilities. "For the first time," Andell explained, "these tolerances
were based on objective data, rather than the educated guesses that
had preceded this approach. The upshot was that we could relax some
tolerances, resulting in cost savings. Other tolerances had to be
tightened, but we had hard evidence to drive home the need with
those vendors."
"Crystal Ball didn't actually solve any problems,"
Andell noted. "However, it gave us the knowledge to sharpen our
focus in crucial ways. Our resources were applied where we knew
there would be rewards. The bottom line: higher quality and lower
costs. This problem might have been solved without Crystal Ball,
but not nearly as fast!"
Andell Associates
is also a member of our online Consultants' Corner.
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