Re: Laser positioning? Gantry or lenses?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "vrsculptor"
<vrsculptor@h...> wrote:

>
> > A rather charming lady friend of mine has been asking about a

machine

> to
> > "cut out all kinds of fabrics from computer designs", since she

does

> > professional costuming, it's going to mean everything from silks

to

> > latex sheet (a nasty one to cut with mechanical tools), so I was
> > thinking inert-gas/20W laser.
>
> Abby,
> I would suggest you look into a 20 watt diode laser. They are

small

> enough to mount directly on the axis. A lot easier and safer than

a co2

> laser and mirrors. I'm no expert but was checking one out a while

back

> for 3d lithography laser sintering. A year or so back I was

getting

> quotes of less than 3K for the diode. May be worth a look.
>
> Roger
>

RF excited CO2 lasers are MUCH MUCH safer than diode lasers. Diode
lasers emit in the near IR (probably around 800-900nm for the 20
watt model you are talking about. Unfortunately, normal clear
materials such as glass, plastic, and the front of your eye pass
almost all of that radiation. It will focus quite nicely into a
very high power density spot on your retina...which your eye does
not really appreciate.

CO2 on the other hand is long IR..10,400nm. It is almost 100%
absorbed by glass, plastic, and the cornea of your eye, meaning
regular $2 plastic safety goggles will provide good protection, and
a stray beam is not going to get focused onto your retina (although
you should really avoid having stray beams).

Just my $.02

Rick