NOTE: Lasers are no toys! With such devices you can seriously damage your or others eyes!
DISCLAIMER: This design is published to show the capabilities of an UMO in cooperation with a laser. I´m not responsible for any harms occuring because somebody copied/used this design.

- drill the center of the alu extrusion to accept the 12mm aixiz module
- print all the parts required for mounting the laser bekow the print head (1x fan coupler, 2x head coupler - decide if you like the long version or the short one) and assemble the laser head
- solder the laser driver electronics according to the schematics ; take care that the resistors and the IC get their heatsink
- solder a cable to the UMO board at EXP3, Pin GND and PIN13. Those pins are located behind the Z-MAX endstop plug. Connect this cable to the relais
- connect the other side of the relais to the power line between the laser driver electonics and the laser diode

For operation, load the startup g-code and use the Z-mod bracket (lenght is 165mm) as spacer between the ply Z-trigger on the left back side of the printer table and the Z Endstop to set the correct z height. Then just clip the head below your printhead (between alu mount and ply part), connect the cables to the electronics, plug in the power supply. Next, clip on the laser beam shield.
For generating the g-code use a suitable software (e.g. cut2d). The laser is addressed via a M42 P13 Sxxx command - S0 for off, S255 for on.

Important note: I learned that in some cases the c-code will not work proper, but I have no idea why. So I have to use an M400 everytime before an M42... 

More infos can be found here:
https://ultimaker.com/en/community/view/9028-hacking-um-to-cut-stuff