Homebuilt CO2 laser cutter

Tony,

May I suggest that you also provide a source for the surplus laser?

Perhaps plans as to how to build one?

TMT

Hi TMT, thanks for your suggestions.

As I mention on the site, we got the laser from a private seller - it was a
one-off purchase.  At the moment I don't know a source other than Ebay.
Some people have contacted me to say they have also bought exactly the same
Lumex laser head on Ebay.

I would like to offer detailed plans in the future.  At the moment it's
really just a $1 e-picture-book.  It is my intention that the pictures show
most of the ideas for people who want to build something similar.
Hopefully I'll be able to offer more later.

Cheers, Tony

This is an awesome project!

I have a question, just to get an idea about laser wattage:

What kind of energy would I need to cut simple paper? 3mm Acrylic? 1mm
Aluminum?

And how does one catch the laser beam after it went through the material?


Curious,


Matthias

You can get an idea of the wattage requirements by doing a Google search
on "desktop laser engraver" (with or without the quotes).

Most folks don't like to cut aluminum with a CO2 laser even if they have
the wattage available because it shortens the life of the optics.
Non-reflective material is the best.

-- Gordon


Matthias Melcher wrote:

Yes, I know it is hard to convince the "laser guy" to get my aluminium
robot parts done. That's why I am dreaming of upgrading my CNC system
and do them myself. Looks like it'll remain a dream unless I go plastic.

Thanks for the info.

  Matthias

-----
Commercial link showing some of the parts I let cut from 1mm aluminium
(in German only - sorry):
http://robowerk.com/de/robots/scorpius/aluminum.html

I remember a comment from a Scientific American Amateur Scientist column
on constructing your own CO2 gas laser years ago, something like

   "put a 2 by 4 in the path of the beam and watch the
   pattern within the beam char itself into the wood."

Perhaps that would do for your purposes of catching the beam.

Hi Matthias, thanks for your kind comment.

The Blake is my first laser, so I'm learning as I go along.  Certainly there
is alot of generous help in this newsgroup from experienced and respected
people like Gordon McComb.  I can only speak from my limited experience.

The Blake Laser is 20W or less.  It can cut 3mm acrylic sheet (see the
picture on the website).  When it cuts, the laser beam vaporises the acrylic
to make the cut.  It doesn't really cut paper - it just burns through it,
leaving a charred edge or just setting the paper on fire.  Similar result
with wood.  It does not cut aluminium - aluminium just reflects the laser
beam, only leaving a very small & almost invisible mark on the aluminium.

To catch the laser beam on the other side there is a "beam stopper bucket".
You can see it in Pic 1 on the website.  There is a hole in the table that
the laser beam goes through.  The beam then hits the water in the bucket.  I
believe that most of the laser energy is then absorbed by the water
resulting in a mild heating of the water.

Cheers, Tony

http:///www.theblakelaser.com
A home-built computer controlled C02 laser for cutting and engraving
One-dollar downloadable e-picture book

Just checked EBay - and yes, there's even a 40W one out there... . I'd
love to retrofit my CNC, but I have crazy respect for invisible light
that can cut my arm off.

Did you ever get burned?


The charred edges would be OK since I need this only to test the design
of my aluminium parts, but I was to tired yesterday to figure that it
would ignite the paper of course. Doh!

Thanks,

  Matthias

Your arm's safe, but it's not a pleasant feeling to be burned by a
laser. It's happened to me a couple of times (10W argon). The burn mark
eventually goes away, but you feel it instantly. Sort of like a bee
sting.

The dangerous thing is the "invisible" light part, and with CO2,
specular reflections that you don't know are there. They aren't
generally strong enough to burn you, but they can bounce back into your
eyes. Days or weeks later you notice little "floaters" in your eyes.
Sometimes they heal and go away, sometimes...

I recall from seeing Tony's pictures before that he included a number of
safety precautions, including a water pail beam stop. I'd probably also
wear goggles with a 1500nm cut, just to be safe.

-- Gordon