Laser Cutter Air Assist

Turn it on, turn it off, automagically…

My laser cutter has an air assist, which is really just a small air pump that runs when I am cutting or etching with the laser. The nice thing about LightBurn is that it adds the commands M106 and M107 to the start and end of each job so it will automatically trigger a pin on the Cohesion3D control board so that it can turn on and turn off the air assist.

Disclaimer: I’ve done a lot of projects using AC power controlled by relays using an Arduino or Raspberry Pi, and I’m comfortable working with 110VAC, but if you are not, I’d recommend you just get an Enclosed AC Relay System for Air Assist/ Exhaust Fans. It’s basically a power strip that can be controlled with two low voltage wires. Quick, easy, and safe.

Onto the project! Above you’ll see two parts loaded into LightBurn ready to cut. I tend to design my own enclosures rather than use any of the online generators, because I’m weird like that, and I enjoy it. You’ll notice the small part is only one piece, so I cut four of them, and they go on the sides. The top piece (to hold the outlet) I just cut another one, without the red parts getting cut, and I’ve got the bottom.

Hey look! All the parts cut from 3mm Baltic birch. Besides the holes for the AC socket I didn’t bother to add any other holes for wires, etc… I’ll just knock those out a with drill and/or file.

But first, we gotta glue things up… and to hold things together, why bother with clamps if I can just tape it up. (Rubber bands would also work. This is small, thin, lightweight wood.)

Basically, add glue… let that glue dry, add more glue. It’s just got to hold together when it’s all done…

Jam the electronics in there. The socket gets held in like a socket does, thanks to the holes on the top. For the relay board I typically use #4 screws to screw it down, though 3mm is a little thin, so I just glued a piece of scrap 3mm in place so I could screw into it and into the top piece a bit if needed… Oh look, I did add some corner supports.

You’ll also notice the wires leading into the enclosure. I probably just drilled holes and ran a round file across them until the wires seemed to fit so I could put the bottom piece on. Quick… and… Dirty!

Boom. Don’t even bother with screws or magnets or other fasteners for this thing… just add some black gaff tape to hold the bottom in place and we’re good.

Wires? Yeah, there’s a bunch of Dupont connectors going to the relay board. We need 5V, GND, and Signal. Simple. That’s all you need to trigger the relay. No microcontroller needed. The Dupont connectors plug into another set of Dupont connectors to change the gender (because I couldn’t find the right kind) and then into some Wago connectors. (Those things are nice!) From there I think I cut up and old 4 wire phone cable. Snip goes the RJ11 connectors!

Here’s the top, it looks not completely terrible, and prevents me from shocking myself with 110VAC, so that’s good.

Hey look, it works! You’ll see a weird switch on the top that the air assist pump plugs into. It’s just an illuminated on/off socket switch I had in the shop and used to confirm that the thing worked properly. I’ve probably removed it by now and put it on my workbench where it’s buried under three other unfinished projects.

Also worth noting: Laser cutting things for your laser cutter is akin to 3D printing things for your 3D printer.