Using the Mp3DP for a laser

Hello all,

I was thinking about using a 3d printer frame for laser engraving. Considering the laser sits a a fixed point on the Z axis do you think its feasible to omit the Z axis motors? I’m thinking that you could adjust the focal length manually with threaded rods and hold it in position with a nut on either side of the carriage. Any thoughts?

Sure could. You could use 3/16" threaded rod to save a few dollars. You’d need something to replace the bearings in those blocks.

The advantage of having a cnc Z is that you can use a script to try different heights to find the best distance. If you have a different material thickness, you can also just adjust it up perfectly.

You’ll still need to get a level bed, though not as precisely. So being able to drop the Z down to the bed will help with that.

So how much will you really save vs. the advantages of having a Z?

Also, you should consider using a grbl controller. the laser engraving is still better than marlin, afaik.

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Well part of this is driven by the challenge of building this out of the spare parts box. I have a cheap laser and the focal length is 58 mm so I was thinking I could just adjust the Z by hand and lock it in.

As far as the GRBL part goes, I know what it is but i have almost no idea how it works. Do you have a preferred website that you could share?

FWIW, Marlin will work fine. The grbl github has the manual, I think. But it’s simpler than Marlin, so probably any guide will get you there. I can’t remember what I read when I tried it the first time.

So here is the update. I am reusing the printed parts from a DOLLY clone for the frame. I learned (enough) about GRBL and loaded it on to an UNO with a CNC shield. I was on a roll with the build and didn’t want to stop and wait for parts so I 3d printed LM8 bearings, toothed pulleys, mock NEMA17 motors for the Z axis, and a GT2 belt extender. I also used some 5/16 dowel rod in place of the 8mm steel rods. I’ll(probably) replace all these with the REAL parts when they arrive. I also need to design and print a bracket for the laser( or maybe the twisted up wire will hold up).

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Whoa! Use those dowels until they fail, I need to know how long they last, that is too cool!

Those parts remind me of something…



I am surprised how well the dowel rods are working. I sanded them down with some 120 grit and then put on a coat of beeswax. By no means are they as effortless to push than “normal” rods, but they do slide very well.

I am using LaserGRBL for the Gcode streamer( . I have never used GRBL before but I am impressed at how well this is working. I also flashed the hex file from 3dpburner onto the arduino in place of the latest GRBL from github. It worked with the github but the jog command was sluggish. It may have been a setting I overlooked but a big part of this project was to learn new things.

Wow, never went that far yet. I remember one YT video trying to build the cheapest Prusa clone.

I was always thinking of using cheap rods from the hardware store and print the bearings, together with the usual 8mm rods that would reduce the costs already significantly.

In the video, he uses hose-clamps and a bit of hose as a coupling, and pretty sure it is fine. I printed some for the MPCNC, after crushing with the aluminum ones into the base plate. You can kiss them Goodby after that. The printed one do just fine, actually because of that, I found out that the stepper motors have quite a bit play in the axis as well.




I have never got that to work correctly for my engraver.
If you go back to GRBL you can run any of the laser engraving programs.
LaserGrbl is (in my opinion) the best free program around.
If you get into it go with LightBurn.
Your dowel setup is fantastic!
I am down with the “use what you have”!
This one is made out of driveshafts from an RC truck and some printed parts.
Yes another lunchtime project.


Answering the question, “What is better than a robot with a laser?”

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:robot: :shark: “… with frickken’ lasers on their heads!”

That’s hard to beat!

The answer is, “A robot with two lasers”


Well, duh! But I couldn’t let a setup like that just sit there, now could I? :clown_face: