31 Jul
2006
31 Jul
'06
2:11 p.m.
Roger Merchberger wrote:
Sure! But, if you aren't prepared to take up MAKING BOARDS AS
A HOBBY (i.e. if you're just going to try it once or twice),
you'll probably be dissatisfied with the results.
And, if you take THAT up as a hobby, you may end up being
discouraged with how it forces you to approach projects
(e.g., having to avoid using certain packaging technologies).
I know that when a client "forces" ("strongly encourages"?)
me to use only certain technologies (e.g., for a board that
will have to be repaired in the field by folks who may
not be particularly skilled with a soldering iron :> ),
it has a noticeable impact on the quality of the design
that I can produce. Certain parts just aren't available
in thruhole technologies. Certain other parts require
(very) expensive sockets (e.g., don't even try to do a BGA
design!). Board size increases (this can also have mechanical
implications -- e.g., a tiny board rarely needs a stiffener
or other support). Etc.
As I said, if you are making a HiFi amplifier or something
with reasonably low density parts (e.g., 1 DIP per sq in)
it's "doable". But, if you are using this as a *tool* so
that you can make things that you want to *use* (i.e. the
"hobby" is the design and/or USE of the item and not it's
FABRICATION), then it just seems like a big timesink for
very little return.
It's not even that... it just doesn't make sense to build
things like these (commodity parts) unless someone GIVES
you a small sh*tload of *chips* that you could otherwise
not use. I went this route building 4MB memory "modules"
for an old Compaq 386 I had 15 years ago (compaq was charging
$150/MB). It just wasn't worth the effort in the long run :<
The etch tank was for prototypes. For production, it didn't
make sense to do boards in house (the chemicals involved are
really nasty!). But, we found that the time required to
make even small lots of prototype boards didn't justify the
hassle. If you left the board in the etch tank too long,
you ended up with gaps in traces. If you didn't leave it
in long enough, you ended up with solder bridges between them.
We even tried using metallic *tape* for some designs (a 2KV, 2KW
switcher) and found it didn't save you anything.
Nowadays, with 3 day boards (order *one*... they'll probably
make 3 - 6 and GIVE you the others! :> ) it's easier to get
the design out of the way early and spend those few days
getting together the components you'll need, etc.
Rumor has it that Don Y may have mentioned these
words:
Top to bottom.
Registration becomes the issue.
Are you speaking of registering 2-sided boards, or of problems that can
come from non-linearity of media for even single-sided boards? In my
experience, it's just not
worth it, nowadays, unless you're making a HiFi amplifier or
something equally "non-dense". Saving a couple of dollars on
a bare board just doesn't justify the cost (in time)
1) experience of doing it yourself?
2) bragging rights?
3) need quick turnaround?
4) 1-off prototypes?
Granted, depending on the application, none of these may apply... and
the costs of a hobby (time & $$) are *never* justifiable, unless
"Because I wanted to" is a valid justification. ;-) E.g., why not
make your own memory SIMM/DIMMs too? :>
Someone was trying to make their own, but the board thickness might not
be a standard thickness for what's available in the hobbyist market,
IIRC... not to mention cutting the boards with the little notches &
whatnot may not be very easy in a hobbyist setting. Lasers good, Dremels
bad... ;-) Years ago we
had our own etch tank, wave, etc. and *still* ended
up pushing board fab to outside vendors (messy process).
Yes, but was that for 1-off prototype stuff, or for a run of boards?
Prototype boards are a lot more expensive compared to a run of 1000, or
even 100. But what do I know - I'm just the Village Idiot
when it comes to board
manufacture... ;-) [[ Done a lot of reading on it, have a couple of kit
systems, but never taken the time to do enough with it to get used to
it... ]]
If you want to do it to say you've *done* it, by all means, try it!
Just don't think of it as a way to save any real time/money.
Better to spend your time finding others that want a similar
design and go in together on a "lot".
--don