Re: Laser Engraving

Hi Graham,

> Date: Tue, 08 Nov 2005 17:39:26 -0000
> From: "Graham Stabler" <eexgs@...>
> Subject: Re: Laser Engraving
>
> > Sealed CO2 tubes have a shelflife of about 3 to 4 years, even if
> > in use or still in the box. After that, their power output decreases
> > (basically).
>
> synrads which are a sealed CO2 laser have a running life of 45,000
> hours+ but turned off last much longer, my 50w kicks out 80W and is
> from 91 and I am told has not been refilled. Degredation is caused by
> CO build up which is caused by the lasing action. These lasers
> contain an exotic set of chemicals and sometimes catalysts to keep the
> gas going even longer.

In respect to laser engravers, I had extensively questioned the life of the
tube because the warranty on the tube itself was much shorter than on the
rest of the machine and their pushing of an extended warranty. (spidey sense
kicking in =)

> > CO2 lasers can NOT mark/etch/cut metals. The wavelength is wrong.
> > You'll need a YaG laser for true metal work.
>
> Low power CO2 lasers are not good for metal and no CO2 lasers are good
> for aluminium and copper. But CO2 lasers are the most commanly used
> laser for cutting steel.

Laser engravers are usually under the 250 Watt level and dont require
bringing in 400 Amp service panel which is what I suspected he was interested
in initially.

Just curious, what wattage is used to cut sheetmetal and 1" thick steel?

> > The power levels (like depth) is controlled by pulsing the laser
> (plus > something else I can't recall at the moment).
>
> PWM is normally used.

That's it... speed (IPM) and frequency (PWM).
The mind is a terrible thing to waste. LOL



Something I forgot to mention...

When using a laser the gases from the material being cut MUST be exhausted!
This is a critcal thing. You can NOT use PVC, Vinyl Sign Lettering, or any
material that has "chlor" in it's name (even with venting). It will release
toxic gases and will damage the optics.

And even with the exhaust, it still stinks WORSE than a skunk!
I don't care, I still would love to have one, or two, or... =)

Some have what's called "air-assist" which can be as simple as a air-brush
compressor or an inert gas. This stream of air is used to help prevent
flare-ups (like wood catching on fire) and to get a cleaner finish when
cutting (not marking/etching) plastics.

Now this is very cool...
The CO2 laser engravers can't do metal, but they CAN etch stone - marble,
glass, clay brick, ceramic tile, etc. The results are stunning!

Oh I did a boo boo... It's not GPC, but GCC.

Here are some samples of what can be done with a laser engraver:
http://www.gccworld.com/app_laser_engraver.html
http://www.gccworld.com/app_laser_marking.html

Jim...





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