Homebrew PCBs

> > Hello!
> >
> > I am following this nice group for a while. This is my first post.
> >
> > I've got old X/Y coordinate table which used to be simple pick and 
> > place machine. There's no Z axis and mechanics is not strong enough 
> > for holding any machine with drill or mill tools. One crazy idea 
> > crossed my mind... what if I put one UV light source to 
> this machine 
> > and plot with UV light directly to photoresist coated FR4? 
> I can make 
> > small optical mask with (e.g.) 10 mils aperture, which 
> floats on thin 
> > air blowing beneath the mask. It could act as single 
> (fixed) aperture 
> > photoplotter for direct exposure of PCB photoresist.... Is 
> this kind of stupid idea?
> > Anyone had experience with that?  Would be UV LED enough? Exposure 
> > time is critical here, but I am talking about PCB prototyping.
> 
> The field of homebreweing PCBs is full of nutty ideas, some 
> of which work.
> I'd call this nutty, but definitely not stupid.  It's worth 
> some investigation to see if it's feasable.


It's already been done.  Works well actually, definitely not nutty.

There's a web page out there somewhere of one that was home made, but there
are commercial versions.  If I recall he attached the film to a cylinder
(which rotated) and the laser was moved across it.  Like a lathe works.

Years ago (like 1990) I worked for a company that did bar code stuff.  One
thing we did was film masters & bromides for bar codes.  These were sent to
the printers who used them to print the product packaging.

The machine was an X-Y plotter with a laser, drew the images on a piece of
film which you then developed.  Very nice sharp lines, very accurate too.

Downsides are it's a bit slow compared to a printer, and you need to have a
darkroom.

Controlled by a BBC micro, of all things!

Tony