23 Oct
1999
23 Oct
'99
4:17 a.m.
<> 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