I purchased the 1 watt S3 Arctic Spyder laser from wickedlasers.com and created an adapter in Sketchup to mount it on the Thing-O-Matic MK6 filament stand and wrote a gMax Maxscript to generate cutting paths.
The laser is powerful enough to cut through lightweight materials such as paper or thin vinyl, dark materials work much better than light materials. It can engrave a fair number of materials also. I've found that "self-stick" vinyl sticker blanks are great for creating stickers or stencils (tattoos!).
A 12 volt solenoid is used to block/unblock the laser light that hits the target surface. The solenoid is connected to the Thing-O-Matic's Automated Build Platform output pins. Using a solenoid to block the laser light is necessary because there is no way to programmatically turn on or off the laser that I'm using. You need to block the light between shapes or you'll have burn marks between the shapes.
Unfortunately you are on your own for hooking up your own laser light blocker solution. My solenoid solution is pretty hacked together but is functional enough to get the job done. It's simply a piece of duct tape attached to a wire connected to the solenoid plunger.
Laser cutting in action: http://www.youtube.com/watch?v=u-Gb6AApnGM
Explaining how to use Gmax to create cutting paths: http://www.youtube.com/watch?v=zv2o-0cIW0s
You can download gmax from here (free): http://www.turbosquid.com/gmax
The 1 watt S3 Artic Spyder laser from wickedlasers.com ($300 USD): http://www.wickedlasers.com/arctic This laser is blue UV laser and is not a toy, it will blind you faster than you can say, "Hey, will this thing blind me?"
Print out the adapter plate model to hold the laser
Insert laser into adapter. Itâ€™s a tight fit so sand the edges down.
Remove hot end from Thing-O-Matic MK6 filament stand
Put laser adapter into filament stand where hot end once was
Save â€œgmax laser cutting script.msâ€ to computer
To generate a cutting path from gmax using attached script (see video: http://www.youtube.com/watch?v=zv2o-0cIW0s)
Download, register, install, and start gmax
b. Itâ€™s free, but Windows only.
Configure unit settings in gmax to make it easier to work with
a. Customize -> Unit Setup. Choose "Metric" and "millimeters" from the drop down menu
b. Customize -> Preferences. Change System Unit Scale to "1 unit = 1mm"
c. Customize ->Gird and Snap Settings. Choose Home Grid and set Grid Spacing to 1mm
Open the â€œgmax laser cutting script.msâ€ file that you saved to your computer (MaxScript -> Open Script)
Show the MaxScript Listener window
a. MAXScript -> MaxScript Listener
Enable the MaxScript macro recorder
a. MAXScript -> MacroRecorder
Switch to Spline editing mode
a. Create tab > Shapes sub tab
Click the Text button
a. Set size to 30mm for starters
Type some text and align it in the center of the grid in the top viewport
Convert the text to an Editable Mesh
a. Right click on object and choose â€œConvert to Editable Meshâ€
Switch to vertex mode
a. Press â€˜1â€™ or in the â€œSelectionâ€ window choose â€œVertexâ€
For each letter select vertices and look at the MaxScript Listener window to obtain selected vertex start and end indices
a. Write down each pair grouping. The laser cuts that path, and then between groups it closes the visor and moves to the next grouping
b. For letters that have inner shapes, like O, P, D, Q, etc.. you must select the outer vertices as a separate group and the inner vertices as a separate group. This is necessary so that the laser visor is closed when it moves to cut out the inner shape. Use CTRL key to add more vertices and ALT to subtract vertices.
Update the vertexSubElements array variable in the â€œgmax laser cutting script.msâ€ file with the pairs of start and end vertices your wrote down
Update the G1_SPEED variable in script depending on material being cut/etched.
Get out of vertex mode and select the object because the script works against the selected object
Evaluate the â€œgmax laser cutting scriptâ€ script to generate gcode
a. In the MaxScript editor window choose File -> Evaluate All
Copy the generated gcode from the MAXScript Listener window into a file that will be opened in ReplicatorG
Open the gcode file that you saved in the previous steps
Manually move laser to center of build platform
Open Control Panel and click the â€œMake current position zeroâ€ button
Place cutting material on build platform
PUT ON SAFETY GLASSES!!!
Turn on laser
In Control Panel click the â€œBuild Platform beltâ€ checkbox to open visor
Manually adjust Z height to optimal laser focus distance
Uncheck â€œBuild platform beltâ€ checkbox in Control Panel
Close control panel
Click Build button
Marvel at your Thing-O-Matic laser cutter / engraver