Is there a way to get Cura to skip infil altogether in areas that are too small?

[thanhtacles 1]

I'll often find tiny structures with little to no need for infill at all and I'd rather have them be hallow.

 

Is there a way I can set a type of Minimum Infill Area, but have it not filled in 100%? Have it be 0% instead? 

 

 

[GregValiant 1,413]

It depends on the model.  Sometimes support blockers work when you configure them for "Overlaps" and set the infill density to 0 for a particular area.  Other times setting the "Minimum Infill Area" to 2mm² (or some other low number) works.  If you have something like a tube and you don't want infill between the wall structures you can set "Fill Gaps Between Walls" to Nowhere.

[DaVinci2000 0]

Hi,

Resuming this topic, as I've got similar request. I'd like cura to NOT print infill in small areas, as it doesn't add any structural strength to the print but instead extends print time. It seems there's just 'Minimum Infill Area' that could do the trick, but it prints solid infill, or to be precise, skin. Attached my model with sliced with 0 and 40 mm2 value. Is there a way to keep that narrow spaces infill free?

 

[GregValiant 1,413]

You can do this with support blockers.  I don't think the Cylindrical Support plugin has been updated yet but it works in 4.13.  You can also design your own part and use it as a blocker.  It appears that a donut about 80mm diameter with a 15mm wall thickness would work for your part.

Bring it into Cura and select it.  Under the Per Model settings set it to modify overlaps.  Select the Infill Density setting and set it to 0.

 

Here we have a hockey puck and a donut.  The donut is configured as a modifier mesh with 0 infill density (and 0 walls, 0 top layers, 0 bottom layers).

 

After slicing you get this...

 

To speed up printing you can also set your Infill Layer Thickness and/or Support Infill Layer Thickness to a multiple of your Layer Height.  If your layer height was 0.2 and you set those infill thicknesses to 0.4 then they go down every other layer.  The "Flow Equalization Ratio" can come into play.  If it's set to 100% and you ask for double height infill layers then the print head will slow down so the extruder doesn't get taxed with the high flow rate of a double or triple height layer.

[DaVinci2000 0]

Hi Greg, thanks for prompt reply. I was considering Support Blocker, but that would be a lot of work to overlap all those tiny segments. With Cylindrical Support plugin it should be much quicker though, but not perfect. I'm still on 4.11, so I can I'll give it a try, and play with Infill Layer Thickness, as I've never used it before. 

It would be great that existing 'Minimum Infill Area' could be enhanced with option to indicate fill %.