UM2 Z Screw clicking

[solid-print-3d 30]

Z screw is clicking during prints, sometimes jumping 10 layers down.

It's clciking is similar to when the feeder motor cant push filament and returns to its last good configuration...a click.... one mississippi, ....two mississippi, CLICK! Over and over again.

When I put my fingers on the Z screw, you can feel it try to make a 2 deg turn or so, then back to the original spot, which is what is making the clicking.

I've uninstalled Cura, reinstalled and tried slicing new gcode. I used to think it was for one part, now I find that it's doing it on a different part. I've reset to factory default on the printer (at least I think I did). I've used different SD cards (again, I'm pretty sure I did)

I say, "at least I think I did" becasue this has been going on for a couple of weeks now, and it comes and goes. At first it was just an annoyance, now, I'm wasting lots of filament and money becasue of this.

Has anyone had this issue with a "possessed" Z screw?

 

[twistx 0]

Haven't had this happen myself but have you applied some of the grease that came with your machine to the screw? When the z motor let's go after a print my bed will sit at its last position but if I give it a just a little downward pressure it will slide down to its home position on its own. There should be very little friction.

Also could it be some bits of PLA are stuck in the threads?

It sounds like a mechanical issue more than a software one to me.

[solid-print-3d 30]

@twistx, thanks, but no...The screws are greased just fine.

Picture this - You've got a large part printing...probably takes 5 minutes just to do 1 layer. You're about 2 minutes into a layer, where the z screw should not be moving at all, and it starts to take on a mind of its own. It starts click every 2 seconds or so.

Now, the screw is nice and greased. It slides up and down smooth. It homes good, it prints good (otherwise).

From what I gather, the stepper motor always has current? Maybe there's an interruption in the current flow?

 

[twistx 0]

Oh, I imagined it was happening during a z move.

I did have a stepper problem on my original and found it had a small slice in one of the wires leading to the controller. It was barely visible but it was causing intermittent problems.

 

[solid-print-3d 30]

Since none of the big dogs have chimed in on this, I'm going to assume it's not one of those quick fixes. I just ruined my 6th 7 HR print becasue the Z stepper decided to jump down 20 layers instead of .2mm.

Opening a ticket...let you know how it goes.

 

[solid-print-3d 30]

Update:

I've lowered the Z axis mAh to 1000mAh in the motion control menu on the UM2. So far so good. This is most likely just a band aid approach though.

My logic is that there may be some problem with the motor controller or motor so the reduced current may help some. It's about 6 hours into a 7 hour print and doing fine.

 

[twistx 0]

Can you swap the controllers around? Move your Z controller to the X axis and visa versa. Should help to narrow down the issue.

 

[solid-print-3d 30]

I'm talking to Simon (illuminarti) about this. I've got it working now at 1000mAh, so I'm inclined to think somethings getting hot and failing at 1250 to 1300 mAh.

Hopefully the ultimaker guys have seen this before and know what it may be.

 

[twistx 0]

Odd. I have my printer sitting on some packing foam to reduce vibration noise. The Z stepper is in direct contact with it too but I haven't had any issues, and I haven't checked the temp of it either. I can never seem to find a definitive answer about heat and how it affects the steppers.

Are there no trim pots on the stepper controllers on the UM2? (I should take my control board off and look but I'm lazy I had no idea you could do this through software until I started sorting out issues with mine. I turned my ultimaker original pots down until the motors ran cool and quiet.

 

[solid-print-3d 30]

Don't know, I'm so swamped all I had time to do was take the cover off and inspect the board for a loose connection or damaged wires. I did notice some brown circles forming on the white portion of the board, directly under the stepper controllers, but this may be normal? The motor itself runs warm, but not hot to the touch...I can keep my hand on it fine.

In any event, the guys at fbrc8 are going to send another board to see if that fixes the problem. My money is on that it will fix it. The motor is doing everything it's being told to do, it seems. Only thing left is some sort of electrical glitch on the board somewhere. Who knows...

Interesting that I'm running it at 900 mAh right now and it seems to be doing fine. I wonder if there's a reason the z is supposed to run at 1250 mAh default?

If I do get a replacement and it works, I will be adding some sort of cooling solution to the undercarriage, as I run these machines 24 hours a day every day, so I need them to perform at all times... a little cooling never hurt anybody. Might add a couple of decibels, but I guess that's the trade-off. I've also seen posts where people are adding aftermarket heat sinks to the stepper controllers. Might do that too since the board will be off anyways.

 

[twistx 0]

Brown circles? That is odd. I just took mine apart and I don't see anything like that. Can you tell if your heatsinks are still attached? I had to reattach one of mine with some thermal adhesive.

The original UM had a fan for the electronics below but I didn't see any under the UM2 which was surprising so maybe it'll help.

 

[garaha2012 2]

Hi Solidprint,

have you solved your issue? I have the very same thing and not solved at all.

I have upgraded my Ultimaker with the official new heated bed upgrade. Everything goes well - only the z axes goes crazy. 10mm drop, sometime once, sometimes twice and then this terrible clicking noise and the rhythm in the screw.

Now, after I read your statements I remember that my cooling fan came off and I run the main board without forced cooling. Could this be the cause?

I would be grateful if you have a solution or if we find one combining our knowledge.

Kind regards

Gunther

 

[solid-print-3d 30]

For a quick fix, I went into the settings on the menu of the UM2, and lowered the Z steeper motor current to 900 mAh. This has been working for me for a month now. Simon was awesome enough to send a new board, which I'm confident will permanently solve the issue, but I'm waiting on some micro heat sinks I ordered to install on the motor controllers before I reinstall the replacement board.

 

[garaha2012 2]

That gave me the hint to solving my problem: For testing I used an extra household fan to blow against the electronic board and that solved the problem. The z-axis controller must have overheated. Probably I damaged the board cooling fan when converting my Ultimaker. Have now ordered a new fan and will see then. Maybe I try to reduce the current when I find out how. Thanks for giving me the right clue.

 

[garaha2012 2]

Another update from my side:

I have replaced the fan for the electronic board. Now the fault free print duration increased from 30 seconds to 30 minutes. Maybe after many more attempts there is a tendency this becomes worse (shorter) again.

It is definitely an overheating problem of the z-axis controller.

I have written to Ultimaker support many times. As my ticket is still not drawn to be answered my question to the experts:

What could I do?

Thanks anyway.

 

[solid-print-3d 30]

did you try lowering the z stepper current? Mine prints just fine at 900MaH, opposed to the 1300MaH that is set from the factory.

 

[garaha2012 2]

I do not know how to reduce the z-stpper current on the UM original. Must be in the firmware. But I do not know how to open or view the uploaded firmware.

Meanwhile I got a response from Ultimaker support and hope for a helpful outcome of the ongoing discussion.