Homebrew PCBs

"Eugene Michael" <eugenemic@...> writes:
> Thanks, Stefan, that's great to have the picture to refer to for this; 
> looks like I'm within the ballpark.  

For an additional picture, see http://www.delorie.com/pcb/first.html

The IC on the right is 7.87mil traces on 7.87mil spaces (0.4mm pitch)
and the 01005 cap is over a 6 mil gap.  So, I'm getting about 2 mil of
variability along the edges.

> BTW, is 300 DPI a good enough resolution to use?

Keep in mind that your "pixels" are 3.33 mil across, so lines below
about 7 mil risk being rendered with only one pixel.  You'll have to
try and see, but I'd think 10mil would be a reasonable limit for
300dpi printers (~3 pixels across).

Note that PCB, the software I use, has a "bloat" setting that can
systematically shrink or expand the copper to try to compensate for
the way your printing/etching system works.  If you're going to push
the limits, you might want to make sure your eda software can make
such adjustments.

I have a test board I use to "calibrate" my etching, which tries
different pitch/bloat settings: http://www.delorie.com/pcb/bloat.png
There's a bloat.gbr and bloat.pdf too, if you want to try it.  The
"bloat" setting on that board is 0.01 mil units.