The 150mw or even higher power UV lasers are available on Ebay, they are used in BlueRay DVD players. An LED would work but it will take a very long time to expose a board. You need lots of joules/sq mm to activate the resist. The exposure spot area is going to be around .05mm to get good pattern definition and its just not going to be possible to mask and focus and LED to that level with any kind of power. Most higher power LED's have multiple junctions which means they are not point sources and such will not focus to a point.
The laser Volkan was using was in the $30 range from Ebay, its best to use one with a glass lenses for better focus and less loss.
The laser module with heat sink was mounted into an ink jet printer shuttle, the board moved in the Y direction on a custom built bed below the laser. The bed was driven by a stepper motor driving a lead screw. He built custom electronics to provide the laser video modulation it was was timed by the plastic head reader strip inside the ink jet printer. As the head moved across the carriage the laser was turned on and off. Once the head scanned across the board the bed was moved for the next pass. He only wrote in one direction because of technical issues with reading the plastic sensing strip.
Even with the carriage moving at full speed in both directions it took about 15 to 20 minutes to write a 150mm x 75mm board, but the image was spectacular.
Craig
--- In Homebrew_PCBs@yahoogroups.com, Slavko Kocjancic <eslavko@...> wrote:
>
> I found that posts but there are 150mW laser involved. And this thing
> isn't cheap. In other side the UV power led is cheap. And I think that
> 3W UV led should compare to 150mW laser. (20x more power)
>
> And my intention is to make that beam aprox paralel to with size let's
> say 1mm squared. And then to use aperture whell wit round holes from
> 8mil up to 40mil, and used gerber stile data to work as old day
> photoploter. Ie not raster scan but vectors...
>
> Just don't know if LED is good enought...
> Slavko
>
>
> On 09/14/2013 09:05 PM, designer_craig wrote:
> > If you are interested in direct imaging a photo sensitized board search back
> > through the posts around Nov of 09 for Volkan. He built a UV laser diode direct
> > writer that did spectacular images. The 400 nm blue-ray lasers are available on
> > ebay. He has some images posted under the Files secton of the forum. These UV
> > lasers are very strong >> 100mW.
> >
> > I took him a board I had coated in AQ3000 (water based photo resist) to try an
> > image. Once we got the exposure set the image was amazing crisp.
> >
> > Volkan also built a drum photo plotter.
> >
> > Both these project on my list of cool things to build.
> >
> > Craig
> >
> >
>