My attempt at a MPCNC Primo Plasma cutter

I am part way through building my mpcnc plasma. If I have to much trouble with EMI I will switch it over to a router. I started making a youtube channel that covers the build with hopes of helping other new people like myself. I probably would not of done this but I broke my back 5 months ago and I was going stir crazy, and a cnc plasma might be fun if I ever keep going on my 55 Chevy build. So far I have only gotten as far as assembling the machine on the table and loading marlin on the arduino.


Nice build, keep posting video’s, subscribed :wink:

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Thank you. I started tinkering with fusion360 and the guffy post processor yesterday and started wiring the Ramps 1.4 to do a little reading and testing on my relay 5 volt pin for triggering the plasma cutter. Should have more videos soon

It looks nice. Can’t wait to see more. And I’ll check out your Youtube videos when I get off work!

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Thank you for the support

Working on figuring out my wiring. Gets confusing when you have more than one color wires going on. Hopefully I get to test it today.

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Well we have movement! Good first start. I need to tram the table , that is one thing I have not done, I ran into some trouble drawing on the machine. I will level it out and tighten the legs up next.

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So it was really easy to change to pin 44 for a plasma cutter/laser once I figured out where the files were. I just searched for pins_Ramps.h and it came up.

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I recognize that shelving! Nicely welded!

I’m also contemplating a Plasma cutter build for sheet metal . Since I bought my Everlast, my old plasma is just sitting around.


I got a whole pickup load of those shelves for free. A local bank closed and they just throw everything away.
I cant wait to see how much the metal warps, I might need a torch height controller or a sliding z axis with more travel.
I’m building the electronics enclosure now.

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I did watch a video the other day of a guy demonstrating the warpage before/after the water bath. Significant difference but he still went with a THC. Surprisingly he got less warp when the work piece ‘welded’ itself to the metal slats as the torch crossed over them.

Keep posting. I’m just behind you.


Well I tested it out. Minimal success but it tries.


Nice work. I was hoping the whole time. I think you’ll probably get there. From the limited amount I have read on the forums, some plasmas are fine and some are just very noisy.

I may be getting there. I have testing a bunch of different shielding, with limited success. I almost thought it worked once, but could not reproduce the results. I am waiting on a relay to arrive to help isolate the wire that turns on the plasma cutter. I will need to try it to see if it even does anything.
Now I have to remember my feed rate used to program my test parts.

Might seem like limited success to you but it looks pretty good from where I’m sitting. A few minor kinks to work out but I feel like you’re almost there.

What’s the duty cycle on that plasma cutter? I’m kind of wondering whether mine will thermal out on longer programs. I have two actually, an old one just good for sheet metal, and then one that’s part of my multi-process TIG. Was hoping to relegate the old one (“Thermal Dynamics” somethingorother) to just CNC use.

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Thanks for the pep talk.
The Eastwood Versa-Cut 40 I am using is listed as 60% duty cycle. I suppose you could always pause the program part way through to let your machine cool down if there was problems.
Most likely your Thermal Dynamics machine is way better than the one I am trying to use. I got a new video out, basically it shows what I didn’t get to work. I tried some other shielding ideas not in this video that I will have to describe later.
It is taxing to have a 2 year old, edit videos, research the subject, and try to capture everything on film.

No need to wait for the relay, you can just hook up the original switch of the torch and manually switch on and off the plasma cutter to see if entirely separating it from the rest of the circuit helps.
How did you ground stuff exactly?

That is why I have a relay on the way. I tested it with the other trigger I had and I ran a whole part.

ah ok, sorry I haven’t had time to watch the whole video since it’s too late here and I’m about to go to bed, only watched the end.
I don’t know if you have watched my old thread already, but I got through the same hassle before so maybe there could be a few tips for you :

If firing the torch by hand seems to solve the problem, then you’re on the right tracks, don’t bother giving any more tries before receiving the relay or you might very well fry your motherboard.
Good luck, I think you’re about to succeed. Your table looks really sweet by the way :slight_smile:

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