Machine is actively zig-zagging up and down

I was doing a typical cut on my machine when it started moving up and down in 7-10mm waves all of a sudden. I paused the machine and it continued doing the motion. Only putting it to sleep solved the issue.
When I woke it up, the issue was gone.
It wasn’t a calibration or getting stuck issue- the motors were moving the sled up and down.
I create my drawings using Vectorworks to DXF and G-Code with F-360. This is a new issue for me as I have done hundreds of successful and calibrated cuts…
I will be seeing if there is a new software interface for the Maslow to download… Barring that I am stumped.
One of the x/y motors was giving me a grinding noise in one direction only, is that a typical indicator of it becoming NFG?
Thank you for any help that is offered.
Best
James

zig-zagging up and down while paused indicates that the PID loop is out of
control, it could be that something is wrong with the encoder on the Z axis

if a motor is giving a grinding sound, it does sound like it’s about to fail.
you can open up the gearbox, clean it out and re-grease it. That would make it
last longer than just continuing to use it as-is.

David Lang

Thanks David
How do I address the x axis issue do you think?
Cheers
J

What board do you have and was the board hot when it started oscillating?

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I did not check if it was hot- din not think to.
I will do next time.
I have a DUE Shield V2.1
Or perhaps you are asking about the other one Arduino with a ± and a Atmel arm chip
Cheers and thanks
J

you said it was moving up and down, I assumed that was the router moving up and down on the sled, but then you ask about the X axis (side to side) which is a very different thing

can you get a short video of the motion you are describing?

My pardons I meant x,y up and down.
I have a photo of what it was doing, I’ll share that.
Best
J

You can also see on the lower cut a less active zig-zag… but it is there
Cheers
Sorry I did not up load the image earlier.
Best
J

ok, that tends to be that the sled is sticking, the chains get slack, and then it jumps (usually doesn’t happen at the top, but it could)

check that the edges of the sled are rounded so they don’t catch and that the bottom of the sled is smooth (sanded and waxed works well)

the question that was asked about the controller is about the board that plugs in to the arduino.

Hi David

It is not sticking
Please re-read my original post.
It literally was moving up and down after I paused the process.
Though I do appreciate your thoughts.
Best
J

My due board did that when it got too hot. That was why I stopped using it. Kind of a weird experience watching it bounce along the top of the workspace.

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Indeed- it was weird, that sounds like a promising solve.
Should I assume you replaced the board?
Which unit did you replace it with please?
Cheers
J

The photo shows that the oscillations are not exactly “up and down” but more tilted to one side. This is consistent with the PID loop controlling one motor is misbehaving. If it were me, once I made sure the sled was moving smoothly (like others have suggested), I’d replace the noisy motor. (And then maybe take it apart once the stakes are lower.) P.S. My recommendation assumes the tilt of the oscillations is “pointing to” the noisy motor. P.P.S. Swap motors, and see it the tilt of the oscillations changes.

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If one of the driver chips is thermally protecting itself that can happen too. Basically one driver chip shuts off to cool down and that makes one motor act strangely.

Thanks to all
After the comment about the duo, I ordered the new board and a new motor- I’ll let you all know how it proceeds.
You are :100: correct- the cuts are angled towards the grumpy motor.
The support is much appreciated!
Best
James

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I have a gen-one board with a shared z and left motor chip ,(2 heat sink board). When it is hot out and the system runs for some amount of time, it does this. It did it 2 times on me. I paused the cut and let it cool, opened the doors so the wind could cool the board and it resumed fine. I went back to using the mega with a custom shield rather than the due.

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