Z-Axis Stuttering when going down

Vertex 3D Printer Vertex - Issues while printing
1

Hi everyone, i have a strange Problem since some time everytime i move my z-Axis down for example at the end of a print it stutters quite heavily after a couple of cms.

Could the z-axis Stage is noch aligned correctly so that something is pressing against the bearings on the 2 Z-Axis Rods ?

At the moment i using a standard flexible z-coupling. before that i had a more stiff coupling with a nema motor dampener installed where the stuttering wasnt that much but still there.

Does anyone have an idea what could be the problem ?

im Running out of ideas.

I also have a z-axis stabilizer installed but i do not thinks that it causes the problem because the stabilizer has been there sind over a year but this stutter began about 3-4 months ago.

Would really apreciate an Idea what to look for.

Best regards

Markus

2

Have you checked the screws that hold the coupler to the motor.

Mine came loose and did something like that.

3

Hmm i will look into that when im back home, i just installed the flexible coupling today and removed the nema dampener, could be that the screws in the coupling arent that good anymore.

thx i will definetly look into that.

Did someone ever have a broken linear Bearing ? im not sure but i was also thinking that maybe the lm10uu on the z-axis might be broken ?

4

That is always possible.
Personally I always start with the simple things first.

5

[quote=“MavRaven”]Did someone ever have a broken linear Bearing ? im not sure but i was also thinking that maybe the lm10uu on the z-axis might be broken ?[/quote]I had one : some of the the balls came loose.

6

Yes, one of those bearings was bad from day one, extremely stuttering when moving the bed by hand without the wire-rod…

Kind Regards
JeAfKe

7

I had a failure during a long print a couple of weeks ago, after 18 months in service. The z-axis stopped moving altogether http://forum.velleman.eu/viewtopic.php?f=62&t=17448#p81115 - a real mess.
It seemed to be the linear bearings had jammed. When I disconnected the coupler I found the movement was very bad - rough and sticking. I put it down to not oiling frequently enough. I didn’t notice any new sounds up to the crash though. I bought a full set of bearings and it seems good now.On the dealer’s web page there was a comment to oil the bearings before installing - maybe that should be mentioned in the K8400 instructions.

I’m still not sure what’s the best lubricant for the z-axis. I use a light machine oil as recommended but on dismantling I found that the fittings at the bottom and the z motor were also soaked as the oil runs down the rods.

John

8

Thanks for the Info everyone, i disassembled the Z-Axis this morning and was kinda shocked.

After disconnecting the z-axis rod from the coupling the z-stage just stood there and didnt move down even though there was nothing holding it up beside the bearings itself.

i moved it a little by hand but noticed that it was extremly hard to move and heard some kind of scraping noise.

After disassemblind the first bearings and looking into it the balls fell out of the bearing, and looking inside the line from the bearrings was weakened somehow and some sparts were stuck and other
parts were falling out of it.

Because i wont get any LM10UU before tomorrow of Saturday im replacing the LM10UU with Drylin igus RJ4JP-01-10 and see if that will do the trick.

At first i will only replace one of the bearrings and maybe if it works good i will replace all 4 later on.

thanks for the help guys i will post a picture/video after im done and its printing good again.

9

I’d be interested to know how you get on with the LM10UU.
I ordered a set based on the comments here http://forum.velleman.eu/viewtopic.php?f=62&t=16339&p=78013&hilit=LM10UU#p78013 but they didn’t work for me.
Following my z-axis blockage I decided to try again.

The LM10UU by themselves moved very smoothly, but when I added the circlips the movement was already less smooth. By the time I had mounted the bed support & z-stage they hardly moved at all …maybe I misunderstood something.

10

Hey Markus,
I had forgotten to mention on Twitter, that my bearing have been changed after a few days. They did not move smoothly.
So I got replacement from Velleman

best
Frank

11

[quote=“pinthenet”]I’d be interested to know how you get on with the LM10UU.
I ordered a set based on the comments here http://forum.velleman.eu/viewtopic.php?f=62&t=16339&p=78013&hilit=LM10UU#p78013 but they didn’t work for me.
Following my z-axis blockage I decided to try again.

The LM10UU by themselves moved very smoothly, but when I added the circlips the movement was already less smooth. By the time I had mounted the bed support & z-stage they hardly moved at all …maybe I misunderstood something.[/quote]

Yeah thats was basicly the same experience i had with the LM10UU replacement vom drylin Iglus, i ordered them also as a recommendation from the mentioned thread and installed all 4 only to finde the z-axis not moving at all of getting stuck in the middle of the z-stage.

In Retrospective i think the Problem was the flexible coupling that Comes normaly with the vertex. Because the drylin are a Little tighter then the lm10uu they seem to Need a bit more force which should be fine for the nema17 but the flexible coupling basicly flexes to much IMO.

At this Point i only replaced the broken LM10UU with one drylin and left the other LM10UU in place because they are still working more or less good and i have a big print order of 150 keychains to complete, but i will look into replacing all 4 after im done with my Project.

Also i replaced the Flexible coupling with a more “stiff” flexible coupling and can only say great Things about this coupling:

ebay.de/itm/221672893797?_tr … EBIDX%3AIT

It has a flexible plastic part in the middle but is more riggid then the original flexible coupling so it works more linear in forms of power Transition IMO.

I can really recommend the coupling, its working perfectly now for about 4 Months.

[quote=“frank.von.thienen”]Hey Markus,
I had forgotten to mention on Twitter, that my bearing have been changed after a few days. They did not move smoothly.
So I got replacement from Velleman

best
Frank[/quote]

Thanks, that was exactly my Problem only that my bearings worked for almos 1 1/2 years without a Problem. But now they are replaced and working like a charm for now :slight_smile:

12

[quote=“pinthenet”]I’d be interested to know how you get on with the LM10UU.
I ordered a set based on the comments here http://forum.velleman.eu/viewtopic.php?f=62&t=16339&p=78013&hilit=LM10UU#p78013 but they didn’t work for me.
Following my z-axis blockage I decided to try again.

The LM10UU by themselves moved very smoothly, but when I added the circlips the movement was already less smooth. By the time I had mounted the bed support & z-stage they hardly moved at all …maybe I misunderstood something.[/quote]

I replaced them again since I had the same issue as the topic starter. Now I have a good set of LM10UU’s which moves a lot better then my first set.

Dylan