Help! Stepper Motors are not Stepping!

Hi everyone,

I feel like this forum is my new home.

So, I'm built, I have power running, firmware has been uploaded and I'm ready to calibrate, but I'm having and issue with the motors. Using PrintRun, I'm testing the device. The bed and hot end heat up just fine, but when I try and move any of the motors, they just jutter in place.

I've attempted to adjust the current to the motors via the stepper drivers and get the same result. The motors do move freely if I lightly push them on my own.

Here's a video of what's going on: [youtu.be]

Please help! Thank you!

When I build my i3, i had a similar problem.

Don't remember how I exactly solved it, but I recall that it had something to do with the endstops and homing.
Before correctly homing and hitting the endstop, the software assumed all axis were already at 0 position, firmware did want to go before home, so went back and forth from assumed home. As said, dont recall how I solved it (took me a few evenings of trial and error, uploading different fw configs), but I suggest to check proper endstop configuration and then us pronterface to do a real homing sequence...

Hope this helps

Check the speed too, if it's too fast the steppers can't step fast enough.

i had jittering when the motors where not wired correctly.

I'd double check the order of the wires, different manufacturers have different notations, some use A and B, some use 1 and 2, some use + and -

its easy to get it completely wrong.

Hi everyone,

So mostly working now...

@rodgerclark -- turns out it was the wiring. Apparently, I had decided to wire it however I wanted too... low and behold, that doesn't work -- so I wired it properly, and viola! Motors are running properly.

@Erick64124 & chngylan -- I'll definitely be doing the homing exercise and speed checks here once I get everything up and running.

Back to the mostly working part:

So Extruder works, X Axis works, Y Axis works, but my Z Axis is doing the same thing as before (it's wired correctly).

One thing I noticed when I was putting this thing together was that it was very difficult to rotate the Z Axis rods into place. I'm wondering if these motors just don't have enough torque to move the rods?

Any suggestions would be appreciated.

Thanks everyone!

Z motors should not be hard to turn, so it sounds like a mechanical fault.

Are the threaded rods hard to turn if they are disconneted from the couplers, or disconnect the coupler from the motor?

BTW. I you have 2 Z motors wired in parallel (normal reprap type configuration for printers with 2 Z motors), if you leave them both plugged in and try to turn one by hand, it will actually generate electricity which will turn the other motor, hence it will seem stiffer than it really is.

So if you want to check the motor + coupler + threaded rod + carriage, disconnect the cable from the motor to get a true indication.


BTW. If the problem is not the mechanics, you could try increasing the current on the stepper driver - but check for mechanical resistance first

To wrap this post up:

My problem with the Z Axis was twofold:

1. The motors we're not putting out enough torque
2. because there was a mechanical issue

@rogerclark -- you were right (again!)

Apparently, one of the nuts had an issue... not sure exactly what the problem was, but it was just very difficult to thread the rod.

After a quick trip to Orchard Supply, new M5 Hex Nuts and I've got all my axis working.

Thanks again for all your feedback. I'm excited to calibrate and start printing!

Polymathiae
Twitter: @polymathiae