Laser Cutter

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We have a Buildlog 2.x 40W Laser on site at Hackerspace. It is capable of cutting, engraving, and marking a number of different materials quickly and accurately when driven from CAD software such as Inkscape.


Buildlog 2.x Laser

Inside the laser cutter there is a very powerful CO2 infrared laser that is bounced off of a few mirrors and is finally directed towards the material being cut or etched by a moving mirror and lens that focuses the coherent beam. These mirrors and lenses are gold coated to provide the best possible transmission of infrared energy.

There are two main variables that the laser uses to cut and etch: speed and power. When cutting, the laser power is increased and the speed is decreased so that the cutting beam spends a longer time hitting the material in order to cut though. While etching the speed is increased and/or the power reduced, this way the laser only removes a little material from the surface, leaving just the etching.


You must take the Laser Operation Class in order to have permission to use the laser cutter. The laser cutter is a very powerful, but also easy to break machine that requires some training to be able to use effectively and safely. Once you have taken the class, you will be added to the Knox Makers Laser Cutter Checkout List.

At this time, we do not plan to schedule the usage of the laser cutter. If usage is heavier than anticipated, we reserve the right to institute a scheduling system to be fair to other users.

When you arrive at the space, remember to sign in and sign out on the log sheet. Please note any damage or issues with the laser when you sign in.


There are a wide range of materials that the Laser Cutter can cut, etch or mark - but some simply don't work (eg metals) and some are extremely hazardous to either humans or the machine itself. It is therefore imperative that you check the list of Laser Cutter Materials before attempting to cut materials that you have not worked with before.

Laser Cutter Settings

There has been some preliminary testing with common materials to generate a set of recommended values for speed and laser power: Laser Cutter Settings. These values have been included as defaults into our laser cutter Inkscape plug-in. The values should be acceptable for the listed materials, and can serve as a starting point for testing for other materials. The laser settings are internally limited to prevent damaging the laser, so feel free to experiment.

Beyond changing speed and laser power, do not attempt to change the configuration of the laser cutter. These settings are calibrated regularly by our Laser Cutting SME and are not intended for users to change. Doing this messes up other people's work and it's NOT COOL. As with everything in the space, when you're done, leave things better than they were when you started. Changing settings could mean the laser is not right when the next person comes to use the machine.


Editor's Note: Do we have anything that goes in here?

Theory: How it Works

Inside the laser cutter there is a very powerful CO2 infrared laser that is bounced off of a few mirrors onto a moving head and is finally directed towards the material being cut or etched by a moving mirror and lens that focuses the coherent beam. These mirrors and lenses are gold coated to provide the best possible transmission of infrared energy.

The infrared (IR) light that the laser cutter produces would blind you instantly if you were to look directly at it - and it's so bright that even you were only looking at the light reflected off the material that's being cut, it could still blind you. The IR light is also totally invisible. Fortunately, IR light doesn't pass easily through the window of the cutter that is made of a Polycarbonate plastic (which strongly absorbs light in those wavelengths). For this reason, if the lid (and the front panel) of the laser are not properly shut, then the IR laser will turn off automatically. The intense white light that you sometimes see when the cutter is operating is actually visible light that's being emitted by the material that the laser is burning off (it's literally 'white hot'!).

For carbon-based (organic) materials (like wood, paper, cloth and leather), you see the material being burned away and there may be black residue left behind. For plastics like Acrylic, the material is chemically decomposed by the laser and you don't see that white hot trail as it cuts. However, when the laser hits the metal grid beneath the material, there will still be bright flashes of light from that.

IMPORTANT: Dirty optics

If the laser cutter is operating particularly poorly, then dirty optics is a likely cause. Smoke and debris can stick to the lens and mirror and build up slowly over time. Editor's note: We should maybe get some of these?

It's a good idea to inspect the laser optics before you start work. Use the mirror and lamp provided (both are supposed to be sitting on top of the laser cutter). Carefully place the mirror onto the vector table, underneath the cutting head and shine the lamp down onto it to illuminate the underside of the head:
When it's dirty, it looks dull and greyish-brown like this:
It should be a golden yellow color because the lens is coated with a thin layer of gold.

It's also possible that one or more of the three mirrors is dirty - but this is a rarer situation because they aren't in the direct stream of smoke that is kicked up when the laser is working.

  • Don't use the laser when the mirror and/or lens are dirty - especially not at high power settings - because doing so causes the dirt to get very hot and that can permanently ruin the gold coating or even crack the optics - which cost hundreds of dollars to replace and could result in the laser cutter being offline for weeks.
  • Don't touch or attempt to clean the lens/mirror unless you've been properly trained to do so. The procedure for cleaning these delicate parts is described in Cleaning the Laser Cutter, but this is a task that should not be undertaken without specific training because these parts are fragile (they're made of a surprisingly soft material) and it's easy to damage the thin gold coating by cleaning them even slightly incorrectly.

The correct procedure if you believe that the lens is dirty is:

  1. Enter your suspicions into the log book.
  2. eMail the issue to the mailing list.
  3. Do not operate the laser cutter or you could end up with...


Making drawings for the Laser Cutter

See Also: Using Inkscape with the Laser Cutter

The recommended software path is to design your drawing in Inkscape, use the KMLaser bundle to export your drawing into gcode, then import the gcode to LinuxCNC which drives our laser cutter.

However, these are only conventions. The only requirements is that your design ends in gcode that is understood by our configuration of LinuxCNC. Laser Cutter Settings is a good reference with explanations of the values you will need to set in your gcode.

External Links

Some helpful laser related links. Need to organize:

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