Hello everyone.
Having UM2 Extended for about a week already, and generally it’s fine… Except ABS clogging and one more trouble getting me every few prints. When I leave printer unattended, almost every time at the random layer, platform jumps a good 3 cm down ruining the print. Anyone had this issue? I searched and found only hardware-related issues. but mine seems fine when lowering/raising platform.
Also I’m using cura and sometimes S3D when I need supports. Problem persists on both.
Any ideas?
Thanks in advance!
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MB3D
2
Does the motor try to lower the bed by 3 cm or does it look like as if the need is to heavy / the motor too weak and because of that gravity pulls the platform down? Does this happen at a random height during the print or always after X cm of printing height? By saying “when lowering / raising the platform” do you mean, that you operate the printer via S3D for example, or do you move the bed down by hand? Can you put something heavy (500g of weight are enough) on the plate and does that change it’s stability? How does the motor perform when controlled via PC and with weights on the platform? Did you check the steps per millimeters / scaling of your axis’ in the latest software? This is a value that tells the software for how much it needs to turn the motor in order to lower the platform by X distance. How often did this issue appear and does it happen with big and small prints / ABS and PLA /… is there any regularity guessable, like it only happens on big prints or only when the heated bed is set to a high temperature for ABS,…
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1. Unfortunately I didn’t have a chance to catch exact moment of fall. I’m thinking about mounting a phone to record it.
2. Yes, completely random, but it the first ~5cm always. By the way, was printing a test vase yesterday, and it printed 10 cm without any issues.
3. It seems that not at all. But I can hear some “crunch” sounds when i’m lowering it by software, but not raising, this is weird.
4. Motors don’t respond at all when I try to control them with S3D, and as for cura, I haven’t found control panel, sorry.
5. No… But prints were fine until some moment. and even now, it’s printing completely failless until some point, or even whole print, like vase.
6. Now it happens every single print, excepting that vase where I used spiralized contour. Small prints usually fine I guess… It happens with big ones. Any material, ABS\PLA, doesn’t matter.
No guesses at all… I even tried to reflash firmware, lubricating Z-Axis, cleaning nozzle completely with changing material. No results…
Thanks for your response
I hope we’ll find this out
I have several UM2’s and I’ve had this happen as well. A quick fix is to go into the advanced settings and reduce the current to the Z axis stepper motor.
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Oh, thank you! Will try now. And reduce for how much approximately?
try 900 mAh.
Like I said, quick fix. Problem is with stepper motor driver heating up and dropping out during a print. If this is your problem, you may need a new board. Ultimaker sent me a new board, but I did continue to print at 900 mAh for several months until I swapped boards.
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Seems that you’re right. Because fast high prints go perfect, but when it’s 2+ hours it makes those falls. I will contact UM for this trouble and thank you very much for your answer.
I lowered just to 1250 and all prints are fine, even big ones. thank you so much!
Just keep an eye on it. 1250 still seems a little high. (that’s what my first couple of UM2’s shipped at). I thought I was out of the woods when I went from 1250 to 1100. Printed fine for a few days, then it happened again. I continued to lower the current until I found a stable current at 900 mAh. This was back when it took 3 weeks to get a spare part 
Upon examination of the board while replacing it, I noticed brown radiating heat marks around the stepper drivers. Easy to spot becasue the board is white. Just food for thought.
If it will lower again, I’ll go with 50 steps. 7 hours print at night went fine. Thank you for the information, will know.
had the same problem, did the same things, no results, i then changed the card, and now it works fine, i got the card from Ali express 100€ and a month delivery (instead of ultimaker 300€ that didnt last more than a year and a half)
