Z axis grind/not moving

Well its time for my 2nd question in as many days…

Everything is up and running relatively ok but my z axis (Nema 23 motors w/ dewalt 611) has decided it doesn’t want to cooperate. I try to move the router up or down and it seems either that the motor doesnt have enough power or the screw is stuck/sticking.

I took the acme screw out and and it through 10ish times back a forth with a drill as well as putting a small amount of grease on the screw. It seemed to loosen the screw up a bit but at this point it seems to not want to budge. I tried both loosening and tightening the belt but neither worked. While hooked up and powered on i can turn the screw with a wrench with a small amount of force.

Any ideas?

You may have a bent threaded rod.. Inspect it for warping.

Did u adjust potentiometer. Replaced a bent rod was making some noise, after adjusting everything else it was the potentiometer.

I used tamiya molybdenum grease, there is a lighter one but for metal-plastic contact is what I have been using since like 5 years ago in my 3d printers.

Greatly removed the screaming sound the Z rod did when lowering the router

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I had a similar issue. Take the threaded rod off and roll it on a table, looking for run-out. That said, my issue ended up being an open connection between U1, pin 18 and J2 pin 4. This is the Z driver side on the G-shield and the Z wiring connector. I had also tightened the ACME rod Nyloc too tight causing run-out.

Look through my thread.

Here is a link to the G-shield schematics…Z axis driver is U1 on page 3.

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Unfortunately, I had a bent ACME rod as well. It does happen and it sounds like you have the same exact symptoms I did. Also, you’re going to want to remove that lubricant because it will attract material chips like no tomorrow and really clog up the travel on the threaded rod. I know from experience. The only thing I would use for lubricant is a dry graphite spray if anything at all.

Called support today and they walked me through increasing the power to the z axis stepper. It worked a lot better, i could move the z axis up and down freely now… Unit I got off the phone with them and tried to carve. With a .25 thick material and the single flute bit i was only able to get 3/8’’ away and the screw got stuck again. It could go up but not down. Gave them a call back and had another screw on the way within minutes.