> Information in this thread is misleading unfortunately. You don't need
> a gas laser to do this. They are big and heavy. There are up to 100W
> laser diodes at 808nm wavelength (IR). Interaction of wave with matter
> is divided into 3 parts which are ; reflection / absorbsition /
>
>=20
> As Bob stated earlier in this thread, fiber lasers are cool and they
> can have tunable frequency outputs. This tunability  will be between
> approximately 1200nm-1700nm in communication wavelength range.Even if
> you change the source of your fiber system (put a lower wavelength
> diode) this system will not work accurately. When you have smaller
> wavelength penetration depth will be lower thus reducing the quality
> of cutting process. Also fiber cable will melt if you put a really
> high power laser diode at source side. Tunable lasers are not for
> cutting and such, they are for communications.
>=20
> Go and buy a 1W 808nm laser diode, they will usually operate between
> 1.8V to 2.2V. Design a simple PWM driver circuit and interface to PC
> using USB or RS232 then you will have a simple laser cutting system ;
> BOM; 50-60$


Misleading is right, your $50-60 leaves out steppers, drivers and other
hardware.  I suppose you could always wave it about.

I'd also love to see that 1W laser cut anything but paper rather slowly.
Burning isn't cutting, edge quality matters.

While YAG (fibre, diode etc) is better than CO2 for various reasons, it
isn't practical, hence almost all industrial machines are gas CO2.  YAG is
very inefficient and uses an enormous amount of power, a 100W YAG needs
about 3000W input, and that's before you add cooling, as you may imagine to
need a lot of cooling.  Even then it'll only cut less than 0.5mm of
aluminium.

A 100W CO2 laser is pretty useless for aluminium (maybe 500W), but it'll be
much cheaper to buy & run.  It needs about 500W input (An RF CO2 would be
about 1000W).

CO2 for acrylic & organics, high power CO2 for metal, YAG for precision
metal or stuff CO2 can't do.

One nice thing about laser CNC is building a 200W machine is about the same
as a 20W one, you can just about swap tubes and carry on.  I had a 35W lase=
r
for a while and I'm contemplating building a 150-200W one.  I think I can d=
o
it for not much more than $3000, and that's mostly tube.  Why, of course, i=
s
why not.

Tony

--=20
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