July 2014 • The PCB Magazine 83
WHY REMOvING YOUR BOTTLENECK IS A BAD IDEA continues
line loading and balanced production). The re-
sult over the marginal case is huge! Why? Prod-
uct being able to pass slower moving product
is a good thing, not a bad thing! For example,
imagine what it would be like on a freeway
where once you entered you weren't allowed
to pass any cars! Imagine what would happen
if granny was driving on the road! Similarly,
if one machine is taking longer than another
to process, the next machine available can be
chosen. The question is how many machines
and extra capacity do you need? This is a so-
phisticated problem that involves tradeoffs and
diminishing returns. For example, the more ex-
pensive the machine then the more difficult it
is to justify adding more capacity.
What does this all mean for us in our shops?
A year ago, I wrote, What is the DAM Problem
with Scheduling (July, 2013). It blows up into an
NP Hard problem (an impossible to solve prob-
lem with today's computing technology) as you
increase the number of bottlenecks in the plant.
One possible way to not only improve your
plant's performance for throughput and cycle
time is to add extra capacity, which would create
a capacity buffer, and to do this in such a way
that you have a well-defined bottleneck in your
factory no matter the product mix. This might
be too expensive or too idealistic to achieve, but
it is well worth thinking about.
PCB
References
1. Factory Physics. Hopp, Wallace J., and
Spearman, Mark L. (3
rd
edition, 2008, McGraw
Hill: New York).
gray McQuarrie is president of
grayrock & associates, a team
of experts dedicated to build-
ing collaborative team environ-
ments that make companies
maximally effective. to read
past columns, or to contact
McQuarrie, click here.
ETI/NEA: Combining Expertise through Merger
by Real time with...IPC aPeX eXPo 2014
guest editor Kelly dack chats
with eti/nea President,
jon Pelletier, who explains
the companies' merger and
specializations within the
industry.
realtimewith.com
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