Homebrew PCBs

On Mon, 17 Oct 2005, cristian wrote:

> > > What's the power requirement to expose a photosensitive board?
> > >
> > > Remember a 5000 millicandela LED will focused down to a 0.0254 mm point.
> >It seems to me someone
>
> It was me, Stevens. Here you are the calculations:
>
> My calculation is  like this:
> For a board of 10x16 cm=160 cm2.
>
> If all need exposured (maximum, no traces at all), it need 16000 mJ.
>
> A 100 mW  beam (laser, or whatever) it needs 160 seconds exposure to get
> 16000 mJ.
> that is 2.6 minutes, a 25 mW laser will take about 10 minutes.

Are you saying that it takes 2.6 minutes to expose a single dot or 2.6
minutes to scan over an entire board?


-- 
David Griffith
dgriffi@...