On 23/06/2011 09:32, Roy Hopkins wrote:
> Could a 1w laser diode be used on a CNC mill to make printed circuit boar=
ds?

No. copper is one of the worst things.
An engraving tool works best in my experience for FR4. Fine end mills=20
wear out and break too easily. I think they are best for precision=20
microwave milling on teflon or other non-fibreglass PCB.

I've wondered about an UV LED (needs lens/collimator etc, or fibre?) on=20
a plotter with photo-resist instead of printing a mask. Likely better=20
edge definition than mask + light box. Or even replacing drum on old=20
laser printer with linear feed for photo-sensitised PCB and then you=20
have higher speed raster instead of slow vector. I don't know what=20
wavelength the laser is in a printer, or if it will activate the=20
photo-resist.

Laser printer actually is a mechanical TV, the "line scan" is a high=20
speed "polygon" mirror (often a 4mm thick perfectly square aluminium=20
plate with polished sides) and the "frame scan" is the rotation of the=20
photo sensitive drum. A fully mechanical Laser projection TV uses a 2nd=20
cylindrical drumlike polygon mirror for frame scan and 3 lasers with=20
prismatic combiner. It has the interesting property that no focus is=20
required. The beam divergence is  designed to be equal to space needed=20
to be filled at the scanning resolution. Thus at ANY distance the scan=20
lines "just" touch. With no focusing. Of course "Zoom" is not possible=20
as the image size vs distance is set by polygon mirrors number of faces,=20
sizea and distances from laser(s) head.





--=20
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