OK, you got your module mounted, it's all wired up and ready to go. Time for some testing!

Safety first! This is a good time to rock those laser shades! As I said before, always have them on when the laser module is connected to it's power supply cable - even when it's turned off! Cable in socket = glasses ON.

Turn your printer on, hook the USB cable to your computer and fire up Pronterface, or your preferred software that's capable of sending Gcode to your machine (like OctoPrint).

The laser turns on if there's 5V flowing to the part cooling fan. This means if you send a command that turns the fan on, the laser also will turn on! Neat, eh?

Before you turn the laser on, make sure of a couple things:

- Have your safety glasses on (again, I'll be repeating this over and over, because it's that important)

- Make sure that your PEI sheet is removed or covered by something (preferably something that's metallic, like a piece of sheet metal). PEI will get burned through instantly if the laser beam touches it. You wouldn't want to ruin your expensive PEI sheet, would you?

- Set the Z height to 50 mm either by holding down and then turning the knob on your LCD, or by sending this command: G0 Z50 .



- On your MK3 LCD, go to settings and turn off Fans check.

- Note that when you turn the laser on, the beam will hit whatever it's underneath it at a constant rate. This means that if you have something that the laser can burn - like paper, wood, leather etc. - it will burn through it or it even could catch on fire! Hence the recommendation to put something that's metallic underneath. These laser modules don't affect metal as much, so that's your safest bet.



OK, now that you know what's about to happen, turn on the laser by sending the command M106 . The laser should turn on and you should see a beam on the surface below it. To turn the laser off send command M107 .

In order to engrave neatly, we have to make sure the laser beam is focused properly at and near the surface. There's a focus ring at the bottom of the module and you can rotate it both ways to find the perfect focus spot.

Turn the laser on and grab a sticky note or a smaller piece of paper. Slide it under the beam and take note of the width of the dot and the mark it leaves while you move the paper around on the surface. While you move the paper with one hand, use the other to turn the focus ring until you see the traces turn to about the width of a hair.