Problem- Wet film + Laser plotter = PCB

[Jake-san]

Im thinking of developing some sort of solution of prototyping boards in a production where we allready use commercial laser plotter machine to make really accurate films for exposing 2 sided PCBs, but I was planning on making some sort of XY-milling machine mod to house a laser (UV) with enough accurate beam to expose the photo sensitive resist we use on the boards.

I was wonding if there is such things out there like Variable Focus lenses, so the fills could be made faster with wider laser beam.. How accurately the axes usually move? Im thinking that we could get away with something close to 5 mils resolution (=0.005" or even smaller), what do you think?

Sorry if this doesn't make sense, english is not my first language and its kind of hard to formulate this master plan to words :P

[MaxMill4D]

Look how it is done by LPKF company.

In reality there is two problems: Make a through holes and make a PCB layout.
So far I think everybody use two different lasers. Would be nice to learn details.

There is metal reflection problem, which I think could be overcome by using, for instance, a black paint. Most energy will be reflected from surface and perhaps would damage the final laser optic.

For drilling would possible to use an YAG laser, but need to find out a power settings for each materiel. LPKF claim it is 3w laser, which I do not believe.

Anybody has wide professional opinion? Please share.