U2 Z-Ribbing

[mikey 0]

Just having had a few non functional weeks with my U2 I started it back up again and noticed an artifact on the prints. It appears to be some sort of z ribbing but I am not sure. I regreased the z screw with the supplied grease but it didn't seem to fix the problem.

The vase is printed at 33mm/s with a temp of 190 and fans are on full after the first 5 layers. And was printed at .25mm layer height.

http://i.imgur.com/Jz5MMDD.jpg

http://i.imgur.com/LMZUr1a.jpg

The issue although less apparent on this bust is visible. This is at .1 mm layer height

http://i.imgur.com/R1fHvAD.jpg

http://i.imgur.com/XDiq9wt.jpg

Any ideas?

These were not sliced with Cura but with simplify3D I don't see how its layer calculation could be off for the U2 but its a thought that I had

 

[mikey 0]

http://imgur.com/wePz6VF

Another example. The printer is finally creating great prints except for the z issues.

[mikey 0]

I lowered the z axis move speed a little. It also might be because I had the setting with layers under x seconds on and it seemed to create a lot of layers of different lengths. It seems to be reduced but that doesn't seem to completely remove the artifact. I'd assume the lack of responses are because its not an obvious fix. I think it all boils down to cooling of PLA as it lays down. If I find anything else to help the situation I will post to help others with a similar issue

 

[mikey 0]

I am still plagued by this problem and I plan on posting more photos of new prints that show this artifact. I would like for some other things to look for as fix, but I have run out of ideas. Something I have noticed which might be completely irreverent but could be a problem is my ultimaker 2 isn't stable. In the sense that its base is skewed and needs a shim under the front left corner in order to not shake back and forth. I received the machine like that and thought nothing of it, but now that I am unable to resolve these issues, I am wondering if it has something to do with it. Any other ideas?

 

[mikey 0]

So here are some example photos from my recent prints. Both are on the latest 14.07 cura with the latest firmware installed. I am starting to become frustrated with this U2, I am going to send a support ticket out because I would really like to get this fixed. I have tried greasing the z screw.

 

[mikey 0]

Okay I am resurrecting this thread once again because I am still having issues. I think its time to open op the z assembly and take a look at the z nut, but I don't know the best way to deconstruct the axist. There were times where I would start a print and for what ever reason the machine would run the print bed into the bottom ignoring the z stop. This was with cura gcode and never simplify3d code and that has kinda pissed me off. It hasn't happened in a while but I am starting to feel like the z nut might be broken. I found this thread from the rep rap forums and it seems to explain my problem and a fix. And after looking at the Ulitamaker 2 files on github the z screw is trapezoidal. Any ideas? I am going to have to go through Ultimaker support but because I have one of the first few batches of machines I'm way out of warranty but I have been plagued by this problem since almost the day I owned the machine so hopefully they help me out.

The outer perimeter speed of this print was 15mm/s and the internal was 30mm/s so I do not know if that exemplified the problem but it is very apparent even with the same speed walls.

 

Is it possible that the z speed could be the cause of the issue? It should be between 35-45 mm/s and I will check after the print finishes

 

[nightwish 0]

Perhaps the travel speed causes a over shooting when hoping? How fast is this set to?

 

[mikey 0]

Perhaps the travel speed causes a over shooting when hoping? How fast is this set to?

 

I'm in the middle of running the u2 extrusion test and am not noticing any banding which might lead me to believe this might a big impact on the artifacts. I'm about to run a few hour long print and will post the results

 

[trevize1979 0]

I realise this is an old thread, but did you ever resolve this issue, mikey? I'm using Cura with a Prusa i3, but I believe I'm getting the same problem as you.

Specifically, the z-pattern is similar to the one in your photos, where the waves seem further apart where the model is narrower, that is, where less time is spent on each layer.