MPCNC: will you make it work? (pretty please!)

Hi Tom,

I enjoyed your MPCNC build! I think I’m not the only one who would love to see a follow-up (I’m planning to build one). People over at V1 seem to think the culprit could be your spindle - but I’m sure you have your own diagnosis.

Pretty please??

Thank you for your great work :slight_smile:

Cheers
Till

I too loved the series, but I took from it that the design might be difficult to tame as far as vibrations go. I’m starting to look at the LowRider-2. I have even done a SketchUp drawing (3D Warehouse, search for “Lowrider 2”) to get a feel of it…

Hi Guys,

I have built a MPCNC and used it for over 6 months. It is absolutely fine for wood (I haven’t tried aluminum or plastic). The recommendations from the V1 site would have had Tom do smaller DOC (3mm or less), about 15mm/sec, and a single flute upcut endmill. My spindle is the recommended DeWalt.

My first project cut through American red oak with no splinters or vibrations, using both a 1/8 and 1/16 inch endmill.

Tom, check out this. His YouTube video shows how the double belt reduces the amount of belt flexing, I think he is on to something.

There is a fair amount of feedback on that last video now.

Did you tighten _____?
Spindle mounts need to be spread further apart.
Z axis reaches too low.
Z axis tube flexes. (I think this would be due to the last 2 or 3.
When chatter happens, slow down the feed rate till it clears up and repeat on this next pass. Failure to slow down on chatter spots will amplify it more and more for each pass.
Do not use the full width of the bit.
Re-enforce this part.
Try a different tool path generator.

That is a loose summary of most of it.

Due to the licensing thing our school has decided to do one from “scratch” using 2020 extrusion. Guess I will post progress here if its ok. It will be open source so if anyone has any ideas how to share designs I/we are all ears. We design in Inventor as the school teaches that so - sorry everything that comes from us is in IPT. I might even resurrect my youtube channel for this if there is a request for that. Currently it operates on a request only as there are less than 100 subscribers (way less) and I/we use it to pass info on to other teams on request like the Volumetric E thing and how to design involute helical gears in inventor

what a shame, I was going to build it. But damn…

Really, when I saw the whole zip tie thing for attaching belts, I was thinking that was nuts and that the belts (I do not know why I said zip ties before) should go through the holes where the zip ties were or that the whole thing was stupid. A clamp down method for holding a belt is what I am used to. Zip ties seems kind of nuts.

10mm zip ties stretch less than he belts. It works just fine.

Since Stefan posted, I reread what I posted and noticed that I said zip ties when I meant belts in one of the spots. Ugh. I keep messing up my wording here and there.

Hi, I am still working on my MPCNC and I have a problem with my X motors. I build this MPCNC with the same components as Tom (Duet2 Ethernet), but I use a 24V powering for the Duet2 and the motors. I connected the motor in the same way as Tom, so I have the Y motors running on the Z connectors and the Z Motor on the Y connector. The X motors I tried to connect in the same way as Tom in his video, but they are moving in a strange way. One is only shaking, the other is moving very rough.
I have no Idea what the problem is. Is it the 24V instead the 12V? Do I have to connect the in serie? If so, could someone give me a picture how the series cableing looks like?
Thank you!
Best regards.
loby

I have these motors:
Nema 17 Bipolar 59Ncm (84oz.in) 2A 42x48mm 4 Wires w/ 1m Cable & Connector

Could it be a problem with the current? I configured the same values as Tom in the video, 1500 for the two motors.
Z and Y are running smooth and correct…
Thank you
Gerd

Make sure your wiring is right for the motor and that both coils are connected. Make sure the little potentiometer on the stepper motor driver module is set correctly. If you have the potentiometer set wrong, it will just vibrate. If one of your coils is not connected (it just takes 1 wire having a loose connection) then you will have movement that is not consistent and easily losing steps.

Hi Nathan_Stenzel,
ok, thank you. I found the M584 command to set up one of the additional drivers on the board for the secound X Motor. That works. I read that this ist better than contct the motors in series or parallel. So I tried an now both motors are running on X.
I am wondering why Tom didn’t use this option too because he uses also a Duet2 board? Is there a reason for it?
Best regards,
Gerd

1 Like

I wanted to build this at first but I saw a lot of videos of different people building this and they all had the same problem. It is weak and the design is flawed for anything more than soft woods. I was still going to build it until the guy who designed turned out to be not such a nice Human. I think if you used stiffer pipe and a better carriage it might help but I doubt it.

I cut oak with my MPCNC with no problems. Ryan is actually a great guy and helps everyone he can on the V1 Engineering site.

-Stefan