OT: how big would it be? - PCBs at home

From: Allison J Parent <allisonp_at_world.std.com>
Date: Sat Oct 23 11:17:37 1999

<> Making PCBs at home is a rediculous waste of time. I have a vacuum lightb

No it's not. Right now I'm doing a design that requires two sided and
design rules down to 10mils. There are three flat packs <64 pins and
and daughter cards for more. The worst part was drilling the 2000 holes
and a 3axis NC machine (home grown is not that hard). Most shops cost a
fortune to drill and etch a 10x8 card with a quantity of 2. Wire wrap for
this design is out of the question.

<I've found that the typical 'cheap' hobbyist's setup (disk of FeCl(3),
<modelmaker's drill, rub-down transfers or a pen as the resist) is a total
<waste of time and energy. But the above stuff, which is easily possible
<to consider for serious home use (remember the sort of tools and test
<gear that I tend to own...) is certainly useable.

I've done boards that way too. Even hand drawn simple RF layouts on the
board with a SHARPIE pen (solvent based marker pens) for one ups.

<After a bit of practice, we could easily make striplines for ECL and/or
<RF stuff, SMD boards (no problem at all with SOICs, PQFPs, PLCCs, etc),
<and of course conventional pin-through hole. The ECL stuff clocked at
<200-300 MHz as well.

The real trick is fine line stuff.

<[As an aside, we found some PCB companies were remarkable _bad_ about
<things like getting track widths right (!), which really messed up some of
<the striplines. We even had boards come back with the layers in the wrong
<order. We _very_ quickly learnt to (a) check everything and (b) do the
<prototype ourselves if at all possible, to ensure the basic design was
<sound...]

There are plenty of things that can really mess up an otherwise good design
and bad etchs are hell to trace in when bring up for the first time.

Allison
Received on Sat Oct 23 1999 - 11:17:37 BST

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