Imperfect walls - Small shifting layers

[Nicko_Airbus 2]

I'm having small shifted layers along my straight walls and I don't understand why... I Printed multiple parts on a same print, a cylindric part is almost perfect, but the straight walls definitively have a problem, can anyone help me ? Look at the pictures. I printed with Ultimaker PLA at 0.15mm layer hieght with 0.4 AA at 30mm/s

[SandervG 1,521]

Hi @Nicko_Airbus, thank you for your post. Perhaps you could try to increase the number of walls or print outer walls before inner walls, it's a setting in Cura. You could also clean your threaded Z axle if it appears on the same level throughout your entire print, but since you say it is only on flat areas I doubt dirt is the issue. Hope this helps!

[geert_2 557]

It looks like the effect is mainly on heights where there is a sudden big difference in surface area? Is that correct?

 

In the past I noticed that when the surface area per layer changes abruptly, this causes visible horizontal lines, a bit similar to yours. But mainly in *small models* (I don't do much big models). So in my case it is most likely due to changes in cooling time per layer, I guess.

 

Do you have the same printing speeds for all (inner and outer walls and infill)? If not, a sudden change of speed may cause fluctuations in nozzle temp and pressure, and that may be visible in the print too.

 

I am not saying that this is the cause, but it might be worth examining.

 

Notice the change in appearance here, when the printing of the outer edge is completed, and only the central stem remains. Huge difference in printing area, and cooling time per layer.

 

 

[Nicko_Airbus 2]

@geert_2 and @SandervG thanks a lot for your comments, I will try to modify these settings in cura.