Re: Laser specs ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Bob Muse" <mtebob1@...> wrote:

>
> Hi Dave
>
> I know that the glass-epoxy board material can be cut with a CO2

laser, having done it myself. Using a small CO2 laser, ~15 watts
pulsed running at ~25%, it was a slow and smokey process. After
trying this once, I set up a slitting saw on the horizontal mill for
the rest of the cuts. A more powerful laser would probably help a lot.

>
> As far as cutting the copper goes, copper is a very good reflector

of IR, especially at CO2 laser wavelength. Perhaps if the copper were
coated with something or the surface was chemically altered--but then
you might as well just etch the board. An excimer laser emitting UV
with very high pulse energies would probably have no problem with the
copper. A YAG laser might be another possibility. If you look at the
absorbtion spectra of the material in question, that will tell you
what wavelengths are absorbed and thus what wavelengths would be good
for cutting.

>
> Bob

I should have been more clear......

I am more interested in finding out what the different frequencies of
light will do.

One of my needs is to cut black foam rubber gaskets from 1/8 to 1/4"
thick sheets. I'm thinking it might be a little hard to use a CD
laser. : )

I have seen some 1 watt lasers that will light paper on fire. kind of
a neat parlor trick , but not all the useful.

I was only mentioning copper and glass as I seem to remember someone
saying that glass is cut industrially with lasers, and I remember a
trade rag talking about cutting copper with one laser that would not
effect the substrate, but.... another laser would not effect the
copper, but would cut the substrate. the pairing of those two in one
machine allows for holes to be drilled thru the fiberglass, all the
way down to the far-side copper. The holes would be plated and a
blind plated via would be the result. neat application.

Maybe another would be putting two balloons, one inside the other,
then popping the inner balloon ?

I am thinking of cutting the foam, maybe labeling PCB's with a line,
instead of silkscreen, probably not strong enough to bar-code metal
tools....

Dave

Dave