LowRider 3 CNC - obligatory "It Lives!" video - having stepper issue - strange sound

Somewhat harsh grinding sound (mostly while going down) from a used stepper motor…

See this video:

Sound going upwards sounds more normal, but down is louder and harsh.

Any ideas? Bad motor? Or perhaps from the lead screw / nut assembly?

It’s hard to tell over a video, but that sounds just like a motor moving very fast to me. Do you know what speed it was moving?

At the very bottom, there was a crunch noise that sounded like a skipped step. But most of the tavel just sounded like a motor working hard to move quick.

What drivers do you have?

That test was done on all 4 newly installed motors on both left and right sides (both Y’s and both Z’s) and only that one Z motor makes that noise. The drivers being used are the TMC 2209s (X from my existing LR3 for Y, and Z from my existing LR3 for Z axis), and the speed was the same as for both the existing first LR3 and the other test of the other side.

The crunch at the bottom was where it bumped the end of the allowed range (hit the bottom of the slot).

Thanks for the reply! I’ll be swapping in another motor from the same batch I bought, to see if the same thing happens.

Another possibility is a broken wire. But i wouldn’t think it would go up at all in that case.

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So, I uninstalled the stepper motor and tested it with no load. Fine. I also tested another motor I was thinking to replace it with, also no load, and it seemed fine. On a whim, I reinstalled the same motor again, and now it travels up and down without that same sound. I’m baffled but planning to go ahead with it as is. Thanks for the helpful tips!

In the not good news category, while I had my case off my existing LR3, to use its board for testing these motors, one of the lead wires (to my TFT) snapped off. Now I gotta fix that. Ugh.

Is it okay if I change that first post since it was a loose wire, not a bad member?

I edited the first post —

I don’t think it was a bad wire, since the same wire I had on there is still on there. Not sure what it was.

The video I posted about a TFT wire having broken when I had my control board case open, is completely unrelated to the stepper motor issue.

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There is a very high chance it was a loose connection. When one wire is not plugged in well that is what happens.

The wires on your board would be a lot safer if you tucked them under the board. I am not sure how your case works, looks like you need some slack in the lines but if that is the case a sliding lid is not a good option, under the board also frees up some room for air to move more readily and keep the hot drivers cool and not melting wires. I made my new octopus case a snap on lid.

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Sounds as likely as anything. Remember it was just a temp connection for a test.

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My wires are all under the board except for the TFT wires. Have double fans. Remember this one connected from top was just a temporary test. I have plenty of slack. However the snap on lid sounds cool. Will check it out. I marked your note about loose wire as solution as although I don’t know that’s what it was, it’s the best idea I’ve heard.

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The one TFT wire that broke was a crimp on connection that was poorly crimped from day one, and it was a break just waiting to happen. My re-crimping job was much better than original was. I noticed its weakness when I first put the thing together. Kinda was watching for it, which is how I noticed it so quickly.

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Hey where is a link for this new case?

I haven’t released it yet. Just got in the new wifi chip so I want to ensure a good fit.

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