Homebrew PCBs

Hi Stefan

Reading my post again, I must have been in a real hurry typing it :)

>i think i described it not precise enough..
>(expected you know the bungard "barrel" exposure plotter).
>
>The idea is to put the film on a drum (before laminating).
>this drum rotates and a laser exposed one line a time.
>(this is what i THINK the bungard unit works - never seen one).

I see.. Well, again, I'm out of the experimenting stage for the
moment. My methods work so well for me that my motivation to change
things is really low. :)

>for use in laser plotter i did think of somehow mounting the film on the 
>photodrum
>and having it exposed by the laser. (tus no run through fuser etc.)
>- would require severe printer conversion thus a separate unit....
>
>main problems:
>a) mechanical - just some tinkering
>b) more important for me: optical
> do you know if the laser wavelength, power/area, and exposure time may 
>suit photoresist?
>i fear not. (sensitivity of photo-drum and film(at wavelength) would 
>require comparision)

Sorry - no idea. How about calling Bungard? I found that Mr. Bungard
is very helpfull and is having a heart for "Homebrewers". I got a
great deal of support with tips etc. back when I was building my
through plating machine. I'm very sure he's willing to give you
information.
>
>I understand there would be alignment problems with double sided - but the 
>alignment when exposing after lamination also needs care.

Of course, I'm also convinced that you might be able to get these
things under control. But - again - for me printing on a foil
(zweckform 2502 type) using an epson stylus c62 does a wonderfull job.

>if the laser in a simple and cheap laser printer would be suited to expose 
>dry film
>without needing to change exposure time (much work i guess) it would be 
>very interesting
>for me (you know i have a lot of problems with this plotter method)

Again, I can imagine that exposing the film this way would be cool but
I do se severe difficuties when it comes to laminate this onoto the
PCB in alignement with other layers. The problem is that you then
would have to manage to laminate it to a very precisely defined area
of the PCB and after some experinece with laminating those materials I
can tell you that I'm usually happy if I manage to laminate wihouth
bubbles or other odities. That said, in order to laminate aligned you
also would have to build a special laminator to achive this purpose
and I think you probably will end up building a device that exposes
(using the laser) and laminates just in one shot.

Just my 2¢ though.

Markus