Why are the first layers of my cubes shrinked on my UM2+?

[bastienb 12]

Hello everyone!

First post so I hope I won't get it wrong ^^. I made some researches but I had difficulties to find an answer to this issue... (better see it on the pics):

As you can see on the previous pics, the base of all the parts is shrinked.

Same problem on another part

For this one, the print goes back to normal as soon as the walls are printed... For the parameters I use this in Cura:

The bed is 60°C, PLA, 0.4mm for the nozzle, 210°C for the nozzle too. I built the Closed chamber ('green house') UM2 by Kris.

Thanks a lot for your help =))

Edited June 23, 2016 by Guest

[00D00B 58]

Hi,

Check that tutorial first to try if it correct the problem but if it's not, then you have a problem with your Zbearing and you'll probably have to change it

[bastienb 12]

Ok, thanks to the tutorial and your comment I have deducted I have two problems:

- Elephant's foot (common and needed for adhesion, not really a problem then)

- Lower wall cave in

This last one is interesting. The printer is brand new, my prints are with a bed temp of 60°C BUT, I know it had fallen from 50cm when I was away... I saw nothing bad (ran test prints) but it could be the Zbearing that took a hit... I will test the cooling thing and keep you updated (and if you have any other advice, do not hesitate!)

Thanks for your help btw

Edited June 23, 2016 by Guest

[00D00B 58]

Tiens nous au courant

[JohnFox 25]

Not seen anything like that before. Doesn't look like a Z artefact to me, looks like both the X and Y are printing too small. What does the object look like in Cura layers view?

[bastienb 12]

Tiens nous au courant

 

Au fait, j'ai acheté l'imprimante à La Flèche

[bastienb 12]

Not seen anything like that before. Doesn't look like a Z artefact to me, looks like both the X and Y are printing too small. What does the object look like in Cura layers view?

 

The heat explanation suits me but... should be smg else... here are the layers (is it good for you?)

[JohnFox 25]

Nothing obviously wrong there.

 

 

Not seen anything like that before. Doesn't look like a Z artefact to me, looks like both the X and Y are printing too small. What does the object look like in Cura layers view?

 

The heat explanation suits me but... should be smg else... here are the layers (is it good for you?)

 

[bastienb 12]

The problem is still there... I stopped making those kind of parts so...

Problem:

All the parts with the same structure (Xmm filled, then Ymm with walls) have the same problem: X first layers are shrinked, the Y next are OK.

Printer

Ultimaker 2+

Cura (latest version) layers:

Parameters

- Regular fan speed at height 0.27mm (layer 1)

Misc

- repRap PLA white, new spool

- 1000hours of printing

- very recently cleaned and lubricated

- door and top cover

- not the Z-bearing -> it depends of the heigth from which the "walls" start to be printed

Things tried

- Still a problem with this method

Ideas

For me, it's all about cooling the first layers more effectively. Somehow it would be nice to adapt the cooling flow to the density of material for each layer. It would mean more cooling for the first Xmm and less cooling for the last Ymm. Simply because the first X are harder to cool than the Y next (less stuff to print).

So the work would has to be done by the slicer... but I do not know how to tweak it!