Homebrew PCBs

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).

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)


I understand there would be alignment problems with double sided - but the 
alignment when exposing after lamination also needs care.

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)



stefan




On Mon, 29 Sep 2003 18:06:28 +0200, Markus Zingg <m.zingg@...> wrote:

>> hi markus...
>>
>> i see, for hole covering it is a good method (maybe the only).
>> i did know that but somehow didn't think of it....
>> but you all expose the film after laminating?
>
> Well - all - I don't know, but for me this is a must. Otherwise it
> will not work.
>
>> maybe it can be exposed by putting it into a laser printer assembly 
>> before lamination?
>
> Well, never tried something like this and I highly doubht if the
> laminage I use would survive the temperatures that the fixing unit of
> a laser imposes. Apart of this - nice idea indeed. But then again, I
> don't think that this would work out reasonably well when it comes to
> double sided or multilayers because of the difficulties with
> laminating this precisely enough. Laminating is a bit tricky -
> especially if the envireonemental temperature goes above 30 degrees C
> (86 degrees farenheit) as it happened often this summer.
>
>> i think you know the bungard "barrel" exposure unit?
>> what do you think?
>
> No, not really. I use a home built exposure unit adn havne't looked
> much around in this area. I also must say that I'm menawhile really
> fully doing this the "chemical" way and so far I'm very happy. Once
> you start to through hole plate, you need that many chemicals that
> developing, exposing and makeing films etc. does not really  matter
> that much anymore. Of course I do agree that other ways could be
> combined etc...
>
> Markus
>
>
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