--- In
Homebrew_PCBs@yahoogroups.com, Mark Lerman <mlerman@...> wrote:
>
>
> I don't know a whole lot about lasers, so forgive my ignorance. Is
> there another type of laser than CO2 that will work for this purpose?
> These CO2 lasers seem mostly to be for engraving whereas just cutting
> through a very thin layer of paint wouldn't seem to require so much
> power, especially since the time isn't critical. I have a cnc mill
> that I'd like to mount a laser on, but I'd really prefer a small
> solid state laser if possible.
>
> Mark
>
Mark, this may not be a direct answer to your question but just to
illustrate how much power is available from a DVD burner's laser diode
(spoiler: not much), I've done some write up and a video on cutting 2mm
(3mm if black only) craft foam with a 200mW 650nm (visible red) laser
diode mounted on a CNC router here
http://elabz.com/laser-cutting-diy/ <
http://elabz.com/laser-cutting-diy/%20>
Given that you'll have to evaporate some surface area as opposed to
cutting a very thin line, I'd say the process will probably be
reminiscent of watching a paint dry. It's hard to tell the resolution of
(the hottest cutting part of) the beam because these things are
notoriously difficult to focus right, even those working in the visible
part of the spectrum. In my case I think it's no better than 25mil but
could be improved if better focusing technique is found.
I'm getting a 1000mW IR laser diode for this machine and focusing the
invisible IR beam will probably be the biggest challenge in the upgrade.
But if I'm successful, I should be able to report on what can be done
with more power (and, hopefully, better heat transfer afforded by longer
wavelength).
So, basically, a takeaway would be that the resist material has to be in
a ∗very∗ thin layer and it has to be opaque black for better heat
absorption and it has to have the lowest evaporation temperature
possible. Personally, I'm not yet sure what material would have to be
used and I'm probably going to have to wait for the 1000mW upgrade in
order to test something anyways.
EOT
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