Plasma Build

I built a MPCNC plasma cutter. It went together really well and if I did run into a problem the forums had a solution. I built it for a class in school for genius hour.

Here is a video of it running.

Thank you for designing the CNC.


Dude, High five!

You need to give us some details, super stoked to see this and I have been itching to build one myself.

Yes… I would like to know more about how your plasma cutter and how your triggering it.

I want to set up my MPCNC to run a 2D pattern from a sketch I would draw. Doll house parts. Can any one suggest a simple drawing program, a program to create the g code, and how to use repetier to run my MPCNC. How do I disconnect the temperature requirements for the extruded? How do I change the code to control the router off and
on? Do I reload this to the Arduino? Will the 3D aspects of the software make it difficult?
Any help would be appreciated.

@Rand, check out the vicious1 tutorials. If that’s​ not enough info, maybe make a topic of your own.

I used Estlcam
go to setup at the top
CNC Programs/Texts/Laser,plasma,water jet etc.
Start Cut
M106 (Close relay on D9)
g4 s0.7
End Cut
M107 Open relais on D9
I used 12V dc coil relay on D9 to switch torch.

Amazon link

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Why am I the only loser who cannot make it work?..

I really need to give it a try again… XD

what files did you use for the printed parts?

Old topic, I know.

Just tried to switch a relay (for Plasma torch) with these settings. According to ( M106, M107 and G04 are not even supported. So I have my doubts this worked for that guy. I’m using Ramps 1.4 with EstlCAM 10 (the last version that supports Ramps).

To me it looks you can’t switch anything at all with this config (Ramps + EstlCAM). There is not a single Output available with Ramps. Even if the guy above didn’t use a Ramps, the G-Code in question isn’t supported in EstlCAM anyway.

Can anyone verify this?

Estlcam to make the Gcode, not estlcam control software, the way most of us use it. Marlin supports those commands.

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Yeah thats really what just came to my mind, too. So easy. Thanks!

Just trying to get my head wrapped around using a plasma cutter as a tool.

I’ve had a Miller Spectrum 125C for a bunch of years and never really liked it as a tool. It was difficult to use because it’s such a low power unit. Although, a CNC machine could easily maintain the delicate speed balance needed to make a good cut.

When I look at some of the other DIY builds out there, this seems to be a popular component to maintain the control of the torch:

Is this something that could be incorporated into the MPCNC platform? Is it overkill? Or maybe I’m just not understanding several things… :slight_smile:



That unit is definitely on the low end. It’s a pilot arc start which is good, but it may run into issues overheating on long cuts. The duty cycle is only 35% at max output, which is rated for 1/8". Even if you did 14ga or thinner, it’s probably going to take all that that machine can offer and you will have to go slow. While it’s easy to try it out, I would recommend a 45A cutter at a minimum, to ensure that you can achieve 100% duty cycle while cutting thin sheets.

Yes, a THC is vital to controlling cut quality, especially on thin sheets. The material will warp as it heats up and be outside the ideal cutting distance ~0.060" for 14 ga and similar. The Proma THC is a popular solution for an external THC. It can be attached to anything because it handles the Z movement independent of the rest of the controller because it can generate its own step/dir commands.

This is the one that generates step/dir pulses which can be used with DRV8825 drivers.

Thanks Bryan, I appreciate the information, it’s helpful.

Every time I look at the 125C, I think about selling it, but now it can at least be a place to start and accomplish basic functionality on the CNC. The THC component you recommended seems like an easier implementation.

So are the DRV8825 drivers native to the Rambo & mini-Rambo? Is there a way to wire the THC directly into the board? Or will it require 1 extra driver? So take Rambo step/dir output to the THC, then THC step/dir to another DRV8825, then to the Z-axis motor?

Obviously, I’m not the best with electronics. I can follow instructions, but don’t understand much about the components themselves.
Many thanks

Great job. What type of pipe did you use? Black iron? What size did you make it