Improve quality of layer other than top layer?

[Jpileggi 0]

In the attached pic, the layer that I want to look great is not the top layer. It is the large flat layer. Is there a way to maximize the quality of that layer in Cura? Am I correct in assuming that a skin layer would be added to the very top (in this case non-critical) layer?

 

Thank you.

[GregValiant 985]

It depends on what it is printing over.  If it's sparse infill then adding another top layer should fix it.  From what I can see of that image there looks to be a checkerboard pattern.  That can be indicative of the infill still affecting the layers above.

[Jpileggi 0]

I'm printing 100% infill.

 

[GregValiant 985]

How do layers 2, 3, 4 look?  If they are OK and if you are printing 100% infill anyway then maybe changing to 50 top/bottom layers would be better than 100% infill on that piece.

It's possible a flow adjustment might be in order.  What size nozzle and what is your line width?

[Jpileggi 0]

I'm using a 0.4 mm nozzle with the same line width.  I was able to improve by reducing the flow rate.

 

But this is exactly my question. Changing the top layer infill would not affect the flat surface since it's not the top layer, correct? Is there a way to change parameters on that layer since it is not the top layer?

[GregValiant 985]

If I understand correctly - what you want is the other way around.

If you set "top layers" to a number > 0 then the "Top Surface Skin Layers" setting is enabled.  When that is > 0 then "Top Surface Skin Flow" is available.

So your general settings would be to get the intermediate layers correct, and then have separate flow setting for the number of "top skins" you set.

If your printer allows for it - have you calibrated the E-steps?  When Cura tells the printer to push 100mm of filament then exactly 100mm's of filament should be fed through the extruder.

 

[Jpileggi 0]

Thanks for your willingness to help me here.

 

Yes, I have calibrated E-steps.

 

So this print has 26 layers. Layer 8 is the top layer of the flat surface that I want to optimize. Are you saying that I would need to set the number of top layers and skin layers to 19 in order to optimize layer 8?

[GregValiant 985]

A "top layer" would include that layer also.  It isn't the top of the part but rather the top skin of any area.

Usually, if there is over/under extrusion it is everywhere.  There really shouldn't be any need to have different settings for the lower skins than for the top skin.

Have you tried ironing?  That leaves a pretty nice surface.  Like everything else, it will need tweaking.  The default flow in the ironing settings is 10% but I found that to be too much for my printer and the nozzle pushed ridges around.  At 7% flow for ironing the surface looks very good.  Leave the "Iron only highest layer" box un-checked and I would suggest you turn on "Monotonic ironing order".