inconsistent Z movement

Phaedrux

Are you using those new motors on the Z axis as well?

Is this a new problem after those recent changes?

You can try bumping the motor current on the Z axis a bit. Try 1300ma.

How heavy is the gantry?

Have you squared up the gantry so that it's even on both sides? If you have a spare driver you could put each Z motor on it's own driver. (just add the second driver number to the M584 Z mapping, nothing else needs to change)

kmart

@Phaedrux said in inconsistent Z movement:

Are you using those new motors on the Z axis as well?

Is this a new problem after those recent changes?

You can try bumping the motor current on the Z axis a bit. Try 1300ma.

How heavy is the gantry?

Have you squared up the gantry so that it's even on both sides? If you have a spare driver you could put each Z motor on it's own driver. (just add the second driver number to the M584 Z mapping, nothing else needs to change)

Thanks for your reply.

Yes i used those motors on the Z and this is only a problem after my changes. Prior to this everything was working reliably, i didn't have failed prints.

I will play with the motor current and see if that makes any difference.
I never weighed the gantry, previously it was a printed carriage with E3D hot end (bowden) on 2 smooth rods.

After the change it's a piece of 2020 extrusion w/ linear rail, still printed carriage but direct drive. So it's definitely heavier... Just not sure how heavy.

Everything is square, i guess the last attempt will be to run each motor on its own stepper. But i did run the same configuration prior to the changes so I don't know if that's really the problem or not... But I'm not an expert.

Thanks again

kmart

No progress really. I bumped up the current as much as i could while keeping the motors from getting hot (1375mA) but i still get the inconsistent Z movement.

Next step will be to try independent steppers for each Z motor. Time is limited to work on this but hopefully i can try and get that setup in the next 1-2 days

kmart

@Phaedrux said in inconsistent Z movement:

M584

So i setup this up

M584 X0 Y1 Z2:4 E3

But now i get this

G28
Warning: motor phase A may be disconnected reported by driver(s) 2 4
Warning: motor phase B may be disconnected reported by driver(s) 2 4

Is this because now one motor from Z is disconnected? How do i fix that?

Phaedrux

What is connected to drivers 2 and 4?
Do you have the jumpers installed in the second Z port?

kmart

@Phaedrux said in inconsistent Z movement:

What is connected to drivers 2 and 4?

Originally Each Z motor was connected to Z1/Z2 (driver 2), i moved one to E1 (Driver 4) for each to be on their own driver as you suggested

@Phaedrux said in inconsistent Z movement:

Do you have the jumpers installed in the second Z port?

I didn't realize in the wiring diagram that there was option A and option B. After seeing that i installed the jumpers and now both motors are moving.

So now new issue. Home x and Home Y lift Z by a few mm. I can see one Z motor is spinning faster than the other because one coupler expands... I doubt this is config related, what could potentially cause this, bad wiring?

Edit, I just realized they're spinning in opposite directions
Edit 2: Fixed that with M569 for driver 4. Will continue to test

Phaedrux

; Drives
M569 P0 S1 ; X goes forwards
M569 P1 S1 ; Y goes forwards
M569 P2 S0 ; Z goes backwards
M569 P3 S0 ; E0 goes backwards

Add driver 4 to the list and set the direction

kmart

@Phaedrux

Yeah i had caught that just after posting. Fixed it and all is good.

Preliminary testing using a feeler gauge is that the height movement is consistent, or at least more than it was before.

But I've been wondering. Prior to all my changes i ran 12V, with the original Anet A8 stepper motors, with the dual Z connected to Z1 and Z2 and never had this problem.

Is there something wrong with the new motors i bought? Should i be looking at just replacing the Z motors with something more suitable?

Thanks,

dc42

The specifications of those motors look OK to me. Check that they move freely.

kmart

@dc42

As far as I can tell they do, and I've quadruple checked the linear rail alignment that the gantry moves freely up and down without binding.

The only other thing i can think of is that i also added anti-backlash lead screw nuts... They were generic off of amazon, maybe they're causing some kind of additional resistance.

I may end up disassembling/reassembling the whole thing and verifying all wiring as well because this is the first time I've been really stumped.

But after a few tests this morning the consistency seems more reliable with independent Z drives so I'm going to move onto the next problem.

Thanks,

Phaedrux

@kmart said in inconsistent Z movement:

maybe they're causing some kind of additional resistance.

That's typically what they do. Sometimes to the point of binding if the motor isn't powerful enough. Backlash is typically not a problem on Z. So I'd try removing them.