Hans Wedemeyer wrote:
> I make double side board all the time. I used to do it the way you
> mentioned, and even wrote a program for my CNC mill to compensate for
> alignment problems.
> I found a better way by printing on transparencies and then aligning
> them visually, then stapling them together. Then slide the board in
> between the transparencies and sandwich the whole lot between two plates
> of glass, and place the sandwich between two lamps
I make boards almost exactly the same way, also using Eagle. I print with a
Brother 5040 laser printer at 1200 dpi on overhead transparency slides.
I've made double sided boards down to 10 mil traces.
I decided to go with Eagle (even though I don't really like its user
interface because of) its stability, the extensive parts libraries, and the
very active support and user forums. Even if I don't find the exact part I
want in an Eagle library I can usually find something close that I can start
with - much easier than starting from scratch on a new part. And if I have a
question or problem I've always been able to get a quick answer on one of
the forums.
Regarding printing transparencies, one minor irritation I'd like to overcome
is that dark areas on the slides aren't as opaque as I'd like, and I've
needed to double up the top and bottom transparencies, for a stack of four,
which is a little tricky to align and keep aligned.
What media do other people print slides on?
Also, I read somewhere of someone who printed "transparencies" on normal
paper and then made them more transparent by spraying them with some
solution (maybe spray silicone?). These resulted in very opaque dark areas.
They needed somewhat longer than normal exposures, but produced excellent
boards. I now can't find where I read this, and would love to know the
details of the process. Are any of you familiar with this?
- Chris Graham