Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, John Johnson <johnatl@m...> wrote:
> I'm thinking about making a photo-plotter attachment for my router / 
> mill.
> Do any of you know of a small UV light source that would be suitable?
> I've found some violet LEDs, but I'm not sure they emit enough in the
> UV range.
> 
> I'll probably include a small stepper and aperture wheel, which I'll set
> up as the A axis in TurboCNC. I could set it up so that A1 would
> turn the wheel to aperture 1, A2 would turn to aperture 2, etc.
> 
> I suppose if it's an incandescent / fluorescent source, I'll also need 
> some sort of
> shutter affair too. I could probably spin the aperture wheel around to 
> a closed
> position.

There are UV LEDs. The question will be how long an exposure.

You'll naturally need to focus it down to a point, which will also
increase the density of light tremendously. A longer focal length will
mean it is less sensitive to changes in distance. But perhaps there's
a way to autofocus? It could only be active while the UV LED is on,
but perhaps the LED could be on only 10% or so all the time for
constant focusing.

Steve