Hi, the laser I used was a secondhand one that I bought from a private
seller, who removed it from some old scrapped medical equipment. I paid a
couple of thousand Australian dollars. This was a one-off, but you may be
able to find someone on the net who is selling second hand lasers. If you
want a new one, maybe try http://www.synrad.com /
Does anyone else know suppliers of second-hand or new lasers?
Hi Hoss, thanks for your kind comment. I'm definitely want to put up more
technical details on the web page. Since this is a hobby project, I'm
somewhat time limited, so it may take a while. I just thought that
initially I would put up as many photos as possible, showing most of the
details of construction. I haven't successfully cut metal yet. Doesn't
seem to cut aluminium or galvanised steel, but does cut acrylic/perspex and
Can you cut aluminum?
I think it would be cool to set up
the machine online. Allow people
to pay you with paypal, then they
send you CAD drawings, the computer
and cutter make the part, and you
mail it to them.
I set up a system like this for making
PCB's and the community college
electronics class used my machine
to manufacture some of their projects.
Guys like Bruce Filener, at filener.com, and Jim Frye at Lynxmotion
already offer these kinds of services. Not sure how successful the
venture has been. I know in my experience (I run a CNC rig myself, as I
believe you do) most people misunderstand the technical requirements of
the CAD drawing. The 0,0 coordinate origin is wrong, they use layers in
some strange way, they include the dimensions as part of the drawing,
they produce the drawing using some odd scale, or the drawing is out of
order, and the wrong things cut first. (This is more of a problem for
mechanical routers than laser cutters, but it can still affect the
accuracy of a laser cut.)
In one picture on Tony's site the Class IV label clearly shows the power
output is max 100W, though this may or may not be what this particular
head can do, as the label looks like it might be generic. That should be
enough for cut aluminum, though I wouldn't blame him if he didn't want
I like the water bucket for the beam stop. Seems perfectly suited for a
10 um beam.
Hi Gordon, thanks alot for your post. You are right that the laser sign
that I put up was just a generic 100W one. My laser power is only about
Is it possible to cut or engrave aluminium with a 20W CO2 laser? I tried,
but most of the laser power seems to be reflected from the surface of the
aluminium. I'm still learning what can be done with the CO2 laser, through
experimentation, research on the web, and advice from others.
What are the main issues or problems with cutting aluminium?
Thanks for your comment about my "beam stopper bucket":)
Firstly: good job :) I have been thinking of doing the same thing for a
while and have accumulated some good parts including a 15W and a 45W CO2
laser (ebay, about AU$1000 for the lot). Could take a while until I get
around to building the X/Y table though.
I would recommend not having the laser mounted vertically, as any junk (eg
bits of electrode) will fall to the lower mirror and damage it. Use a gold
front surface mirror (ebay) or a polished aluminium/copper plate to turn the
I seriously doubt you will be able to cut even thin aluminium with that
laser. Almost all the light will be reflected. I think you may be able to do
laser marking though, but you will have to coat the aluminium first.
On the Synrad site they have a "laser calculator" program that may be
useful. You select material to cut, thickness, and laser power, and it will
tell you the expected cutting speed.
As Daniel mentioned, a 20 watt CO2 laser is not sufficient to cut metal.
At best you'd be able to "etch" it only lightly. So, this rig is pretty
much for plastics and thin wood.
You have to be careful with metals anyway, especially aluminum, because
as you noted the beam will reflect back into the laser, or against the
lens or laser head. Damage to the laser can result. Some shops wigh
higher wattage lasers will accept these jobs in order to get the work,
but a lot of them refuse.
The ony thing about the water beam stop I wanted to mention is that
there will be some specular reflection, even though the water will
absorb a lot of the beam. Maybe work up a dark plastic chimney or pipe
above the bucket to trap any light that is accidentally reflected off
the water surface.
Metal is really reflexive to the 10um wavelenght of the CO2 laser at
normal temperatures. At high temperatures this changes and the metal can
be cut. So, with a 20W laser you probably won't be able to do anything
with metal. Steel is easier to cut than aluminium, and copper is very
hard. If your optics aren't specified to work with metal (it must behave
like an optical diode), you can even destroy the laser head. With 200W
I've been able to cut thin sheets of metal (steel, can't remember the
exact thickness). Organic materials are very responsive to the CO2
laser. Don't try to cut PVC also. It cuts really well, but the exaust
gases contains Cl, and that bad for you, the optics and many other things.
Hi Rich, thanks. I haven't been able to successfully cut aluminium. I am
getting a reflection of the beam. A similar result with galvanised steel.
Thanks for the online machine suggestion.
Hi TMT, I'm going to put up more technical details on the website. Since
this is a hobby project, I'm somewhat time limited, so it may take a while.
I just thought that initially I would put up as many photos as possible,
showing most of the details. I constructed the drive electronics for the
stepper motors using bipolar transistors and a CPLD board for the step &
direction decoding. I'm using Danplot software, which outputs signals to
the parallel port. To turn the laser on and off, I currently have a
microswitch attached to a stepper motor, which is the Z-axis motor. I will
be changing this to a pulse width modulated or delta-sigma signal to the
laser, for variable power.
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