Hello Sage,
I have done some tryntific tests by exposing a photopositive PCB with the common 405nm laser diodes from HD-DVD and Blueray players.
Here are the results:
http://www.flickr.com/photos/98835706@N00/5234166236/in/set-72157625407033197As you can see the results seem hopeful but still need to do some experiments, but I need a good test setup where you can vary laser scanning rate and power.
My first idea was to use a polygon mirror assembly from a laser printer or copier, change the laser to a 405nm one with collimating lens and scan the whole PCB via that method. The idea seems workable as seen on this youtube movie:
http://www.youtube.com/watch?v=G9h9tzfpaY8I intend to do something similar later. My first plan is recycle a inkjet printer carriage and scan with a optical pickup unit from a blue-ray burner (much more powerful laser, around 80mw) instead of the ink cart. I have a set of those pickups ready for reuse.
At a later stage I am going to replace the carriage with the polygon assembly. This will require a lot more work but will increase the scanning speed.
Greetings,
Bart
--- In Homebrew_PCBs@yahoogroups.com, "drsage2007" <davesage12@...> wrote:
>
> Perhaps you all can comment on whether you think this flash from the past will work.
>
> Back in the day I used to plot PCB's using an old flat bed plotter with water proof ink in the pen. Getting the pens to work reliably and cleaning them was always a headache.
>
> All this talk about UV resist got me thinking - what if I were to mount a UV LED (laser diode?)with a lens or whatver it takes to focus a small dot on a board on the table and put it in the plotters pen hoder. I then coat the board with UV resist and let the plotter expose it. I might even be able to use the pre-sensitized boards.
>
> It plots really fast so I'm not sure how much time is required to expose the resist. But some of the LEDS from CD burners can apparently burn paper so given that the exposure is an intensity vs. time sort of thing it might work.
> The pen-down signal could easily be used to activate the LED and not much modification would be necessary to the plotter.
>
> I have an old Roland DXY800 plotter which for some strange reason is still supported by Eagle 5.xx so it creates files ready to go to the plotter.
>
> Any comments on if this would work?
>
> Sage
>