Bottom Layer Bulge - Adjust Top and Bottom Flow Independently?

[ssashton 2]

Hi,

 

I find that all of the bottom solid layers in my models have a bit of a bulge. This is not helped by the setting 'Initial Layer Horizontal Expansion' because it is all of the solid bottom layers, not only the first.

If I reduce Top/Bottom flow it helps, but go too far and the top layer gets gaps in it while the bottom layers are still over-extruded.

 

I do not believe my 1st layer is over-extruded, picture attached.

Any idea how I can correct this, or can I request allowing flow for top and bottom to be adjusted independently?

 

[ssashton 2]

The above picture doesn't seem to have full details, so here it is again:  

 

Image Here

Edited December 6, 2022 by ssashton

[MariMakes 199]

Hey @ssashton,

 

I think you are experiencing Elephants foot. 
There are a number of ways to resolve this. 

Settings that I would consider changing to improve this are: 
- Buildplate Adhesion
- Buildplate temperature
- Initial Layer Outer Wall Flow
- Bottom Pattern Initial Layer - to Concentric
- Initial layer linewidth 
- Number of slow layers

I hope these help. Else it helps if you start searching for Elephants Foot. It might differ per material and printer. 

Good luck 💪

[ssashton 2]

Thanks for your answer. Unfortunately these settings do not resolve the issue.

I find that although the first layer is good, the 2-4 solid layers are over-extruded / too much flow.

 

I would like to make a feature request to have independent bottom and top flow.

 

Here you can see the infill of solid bottom layers. If I adjust Top/Bottom flow down in Cura so the bottom layers are good, then the top is under-extruded. This is not resolved by adjusting the 1st layer.

 

 

 

 

Edited December 21, 2022 by ssashton

[MariMakes 199]

Hey @ssashton,

For me it looks like your nozzle seems to be too close to the bed!
I'm seeing some "snail tracks" that indicate that the material is oozing out from the sides. 

 

That would also explain your elephants foot!
Because it usually corrects itself the higher your printjob goes.

Can you try leveling your bed again? Or trying a different leveling procedure than you are used to for your 3D printer?