3D Printing Forum

Is as hard as assembling that part. You need to do the z bed calibration (screwing one at the time, pull up/down, screw, up/down 5 times, etcetc). Google Ultimaker 2 assembly manual and read page 34

I was more wondering about how much of the rest of the printer I have to disassemble first - everything that is assembled from page 20 to page 34 in the assembly manual?

Not at all. Just remove the z shafts, that can be tricky since I think UM push that part with a hammer. Apart from the z shafts, the rest should stay there afaik

I could not get the z-shafts out on my machine and then it is quite a lot of work, nothing I would do for fun at least.

Unfortunately I think I replaced my bearings with non-Misumi ones, at least they did not come in such nice boxes and the new ones also appeared to have slight sticking issues.

I just uploaded a video for you who want to check the bearings on your machines.
It is quite easy, just remove the Z-motor and move the bed up and down by hand like this:

UM2 shafts indeed ain't easy to remove as umo/umo+. But it could be as easy as drilling with a 12mm bit and printing some caps.

Anyhow that Z bearings look awful.

Also i would not recommend to test them like that. I would do a printrun usb connection and move it on 0.01 intervals to see if it jumps/stays stuck.

Anyhow if your bearings move like Anders video, toss them to the darkest pit.

I found it difficult to diagnose the bearings by printing on this machine, surprisingly.
Somehow it appears that all the shaking when printing makes the bearings less likely to stick, I think that 90% of the prints still came out fine with those bearings in the video (!).

Yea, use printrun/pronterface and connect by usb, do home, move Z near head, and then move z on 0.01 intervals waiting each time a sec. that's the best way to be sure that they work and won't destroy a print.

Anders Olsson wrote:I just uploaded a video for you who want to check the bearings on your machines.
It is quite easy, just remove the Z-motor and move the bed up and down by hand like this:

Yup, that's the same behavior I have. Move it up and release and it will stop after approx. 10 mm.

Yeap that looks no good at all

@Neotko: I'm really looking forward the weekend to print your files for Gudo's Z holder on the UMO Been sourcing all the parts needed this week I hope that'll help me fix Z quality

Tomorrow I upload all. I want to change a detail so is easier to install it without removing the z shafts (is doable at the moment but requires a steady hand). Is a easy change so it should be fast.

Well, Nilrog, you have a fun weekend project to work on!

On the UM2Go it was a pain to disassemble the parts, everything is so tiny in there, to get the electronics board out you need short and tiny equipment because no screwdriver fits underneath the print bed. And I've done this about 10 times, first trying to clean the bearings several times and testing until the final replacement. The new z-nut and bearings Trideus sent me were the same (crap) quality as the old ones, so that didn't work, and finally ordered myself the Misumi bearings and new a z-nut. I can now disassemble the bed with my eyes closed..
From day1 after I bought it the issue was there, look at around 1 minute in the video, the bed stays at the same height, the crappy bearings don't slide, until the play from the z-nut forces it to continue:

In this case the bed of the UM2Go has not enough weight to push itself down and starts printing double layers on the same height.

The other issue that shows is when the bearings are hanging the bed until they find a spot were they do slide and it drops because of the play in the z-nut, resulting in a sparse layer.

Wouldn't this be resolved with an anti-backlash nut ?

I guess so, I think all the issues are related to the z-nut: if there is no play in your z, the bearings have to come along, good or bad.
If your bearings are good, the z-nut has less influence. When both are bad: you're in trouble...

Hi all !
Hi PeggyB, just my 2 cents
Before disassemble too much things,the tip for a quick check of the good sliding of the bed is to unplug the Z motor wire from the electronic cart then remove it by handly turning the Z screw from the printer, so the bed is free and its sliding could be verified easier, if it slides smoothly all the way you will sure that is not linear bearings probem, as the Zmotor is out of the machine it also easy to check the Znut with the trapezoidal threaded shaft, if it's satisfactory, that will mean that the problem would be elsewhere,