Add a Laser to Your CNC Machine Running LinuxCNC and Fusion 360

There are a lot of laser kits on the web but very little documentation on how to operate them or what to expect from them. How do I get started? Can I cut through steel with this...? This is not a highly technical document but simply a practical example of how I added a laser to my CNC machine in order to give you courage to try this yourself. You'll likely find it is easier than you think.

Supplies

Laser kit with mount, circuit board, wiring and safety glasses.

Step 1: How Big of a Laser Do I Need?

How big of a laser do I need? One of the problems with the lack of documentation is knowing just how big of a laser to purchase. My laser was stated to be 30 watts but that turns out to be the input power and the output is around 7 watts. With 7 watts I can etch very nicely even in very hard wood. It doesn't touch steel or aluminum. It will melt plastic. You can change the depth of cut by slowing down the speed of the CNC machine. I found 25 inches per minute cuts in very nicely for etching on signs.

Step 2: Mount Your Laser

Mount your laser close to the spindle/router on your CNC machine. I simply added a small bar to the side of my spindle mount. I purchased a kit that had a mount which made it simple to install and adjust the height. There is another instructable with instructions on printing an enclosure to keep it dust free. I simply remove my laser when I am using the spindle. My kit came with a small power supply but I already had 12 volts available which was needed for my breakout board. I ran Cat5 network cable from the breakout board to get the 12 volts and the pulse width modulation (PWM) signal to the small circuit board supplied with the kit.

Step 3: Post Processor

You'll need a post processor for LinuxCNC. The standard post processor in Fusion 360 will give you an error message when you try to post with it. With some searching I found this post processor that worked perfectly without any modification for me. https://forums.autodesk.com/t5/hsm-post-processor-forum/linuxcnc-plasma-laser-post-processor/td-p/8112836 Scroll down until you find the downloadable post processor called Linuxcncplasma_ganta.cps. Download this and add it to the Fusion 360 library of post processors.

Step 4: Testing Your Laser

Testing: These lasers have a parameter somewhere in their description about how high they should be from the piece you are engraving/cutting. My laser doesn't make much difference engraving on wood from between 1.5 to 3 inches. Make sure to use the safety glasses and do some research to make sure your safety glasses protect you from the wavelength of laser you purchase if they don't come in your kit. Smoke interferes with the laser cutting quality so we started by using a vacuum but a small fan works nicely. I plan to mount a 3 inch fan to my Z axis.