In The Trenches
Starting with calendar year
2004, we are archiving a years’
worth of issues on a CD that
can be searched, printed, and
easily stored.
testing is important information for
the client.
New production/test machines or
special training might also be needed
for production. This is where you
define exactly what is needed and
where to get it.
For example, if the customer
needs an oscilloscope for testing,
you should specify the important
specifications of the oscilloscope
(bandwidth, etc.) and provide any
manufacturers and models that may
be suitable.
It should be noted that, with
faster and faster time-to-market development cycles, Steps 4 and 5 are
sometimes skipped. Instead of building a prototype and letting the customer examine it, the cycle jumps
directly to building a production prototype. This is faster, but carries some
risks. A production prototype
requires more resources and may
include financial commitments
that are not needed for an ordinary
prototype.
You’ll be able to purchase said
disk from us for your own
personal use and dispose of
your old paper copies that are
collecting dust in the garage.
(Your spouse will love you for
it!)
Build Production
Prototypes
We will also be archiving earlier
years as well, so stay tuned for
their availability.
The expected shipping date is
May 15th.
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NUTS & VOLTS
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With the information from the
client in the Product Design Review
and performance data from the prototype, a small number of production
prototypes are build. The number
depends upon the size and complexity of the product. Typically, it’s three
to six units.
This step has two main purposes. The first is to show that the product can be built in quantity with consistent performance. With a handful
of units, you can compare performance and see the variations between
them. If the design or approach is
poor, it simply may not be possible to
produce units with repeatable performance. Talk to any production
manager. He’ll have plenty of stories
to tell.
The second purpose is to create
some “production” units without
actually having to set up a full-blown
production run. These prototypes are
virtually identical to the final product
in every way.
By necessity, there are very slight
differences from the actual production units. This is because of the
small quantity of the prototypes
produced.
For example, parts may be soldered by hand instead of using a
wave-solder machine, or the front
panel cut-outs may be drilled at the
machine shop rather than with a
punch-press machine. The performance, form factor, look, and feel will
be identical to the full production
units, though.
There is one very important additional difference. These units generally don’t pass any quality control tests.
They are handcrafted and tested for
functionality, but their solder connections are not inspected, nor are the
crimp connections, etc. Quite often,
engineers themselves will replace
parts and, while most engineers can
solder adequately, few would pass
quality standards.
This means that the prototypes
are not suitable for selling. It is important to stress this to the client. Never
sell a prototype! It’s bad business.
Besides, some time in the future,
someone will need a unit for something (an upgrade, revision tracing,
or testing). Use the prototypes for
that.
The drawing package (
documentation) is also assembled at
this stage. Note that I say “
assembled” rather than “generated.” This
is because documentation should
always be an ongoing effort.
Creating everything at the end takes
longer, is less accurate, and is rarely
complete.
The documentation (for a typical electronic product) should
include the items on the following
list. Note that the list is not exhaustive and is really more of a minimum guideline. Think of what documentation you would like in order to
manufacture the product and then
include it.
88
1. A complete schematic diagram.
It should be annotated by the design-
APRIL 2005