Ray said:
I was more interested in the process involved. Telling me to buy
a ready made box is I suppose not a bad idea, but it doesn't
teach me anything new. Assume I can absorb the cost and all the
rest of it, what tools do I need for the design, what experience
do I need for the design, what knowledge do I need for the
design, what materials are available, if plastic - what sort of
materials, what sort of colors, transparant/non transparent,
patterns and textures. Certain plastics are softer than others.
How do the design packages/software change when I choose
different materials.
So, you want to learn all the stuff a company knows about
enclosure design, to get "the pro look"? I concur, some
(paper) drafting texts and/or CAD practice ought to do you a
lot of good for the final design stage. But before that, you
also need to consider some other things like:
Heat management (will the case temp damage any cosmetic
plastics, do you provide ventilation, active or passive, how
much, do you need to add a fan, how do you wire it in, will
you need a bigger fuse, [which gets recursive because you
have to modify the power supply], is heatsinking components
to the case OK, are insulators needed, what kind and so on)
Mechanical issues (how to mount the circuitry bits to the
box, is it OK if screwheads show, how to stabilize/isolate
anything vibrating inside, is it gonna sit on anything else
so will it need antislip feet, if so how large and how
"nonslippery", will anything sit on it so how strong does it
need to be, is servicing an issue so how difficult should it
be to get to replaceable parts like fuses)
"Real estate" competition on the floor/desktop it'll
occupy (is a particular shape dictated by styling or is it
dictated by components)
and so on.
That's the main reason prebuilt boxes are so often
recommended for DIYers; a lot of that work is done for you.
Granted they're sorta generic, but you can dress them up any
way you want.
That's just some of the engineering details. As for
plastic/metal, the Big Boys often start with styling;
Marketing cobbles up a shape, texture, and color scheme,
then Engineering has to contort the hardware to fit. For a
DIY, it's largely a matter of taste once you get the other
issues settled (or you can do it like the Big Boys do if you
don't mind the recursive headaches). Selecting materials to
satisfy your esthetics then depends on your confidence in
your abilities to work a given material. I don't know why
you ask about this re: software; in the Corporate CAD world,
a solid is a solid in most packages and AFAIK nobody cares
until the actual toolmaker has to specify drills, punches,
dies, and so on because as you mention, some are softer,
brittler, etc. and need special (read expensive) handling.
As this info comes back to Accounting, they may sign on to
changes which Marketing has to approve, and so on. Besides,
if you're gonna do this yourself, why learn something you
won't need (like expensive software)?
So look at some commercial "pro look" stuff and think
about the manufacturer's priorities; was form more important
than function, the other way around, or did they strike a
balance? What would you do differently, and why? Is what
you'd do feasible and/or cost effective?
Sorry to be so boaring (probably), but I have absolutely no
knowledge on the subject and I need a sort of overview of
the process.
Many of us have held jobs in all the fields involved
(and/or overheard skull sessions in other departments), so
that's how we got our overview. Nothing teaches like
experience, but you can try plowing through texts on all
these subjects and learning at home.
OTOH depending on your age, lots of companies hold open
house days where students can tour various departments to
see how the Big Boys do things. Hell, sometimes they even
let adults in...
Oh, and as Bob Masta says, the package may end up costing
more than the contents. OTOH if all you're investing is your
time, and you reap all that knowledge, it may be worth it.
Accounting departments like OJT, too. ;>)
Mark L. Fergerson