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I've recently purchased an Ender 3 and have had great success with some Cura settings found on a YouTube Tutorial at 0.2 mm resolution.

So then I noticed that there were default settings in Cura for the Ender 3. Except printing at 0.2 mm it selects a 20 % infill, and when choosing 0.1 mm it changed the infill to 10 %.

I changed infill to 20 % and attempted to print this but there were gaps in the bottom layer and it won't stick to the bed. Is there anything else I need to change in the process?

The shape is essentially a cube with a circular hole in the middle, sliced in half.

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  • $\begingroup$ If your first layer is too thin you can run into problems getting the layer to stick, is your first layer also smaller with the 0.1 profile? $\endgroup$
    – 0scar
    Nov 29 '18 at 19:20
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    $\begingroup$ Do you have a link to the YouTube video? $\endgroup$
    – Greenonline
    Nov 30 '18 at 5:15
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The more infill, the more material. The more material, the more stress is inside the part while it cools down from printing temperature to ambient temperature. Parts with higher infill density tend to warp more (the edges curl up).

But 20 % should be fine, you shouldn't have any issue at that percentage (unless you're printing with ABS/ASA).

I think it's a first layer issue, the 0.2 mm first layer gets more 'squished' onto the bed, thats why you get better adhesion. I'm using PrusaSlicer, every default print profile in PrusaSlicer uses a 0.2 mm first layer, maybe there is something like that in Cura too?

For example the 0.1 mm PrusaSlicer profile will squish a 0.2 mm first layer onto the bed and changes to 0.1 mm layers for the rest of the print.

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  • $\begingroup$ Squished amount depends on nozzle to bed initial distance (paper thickness) and overextruded first layer, not on the slicer initial layer setting. It does depend on z offset that is available in some slicers. $\endgroup$
    – 0scar
    Dec 17 '20 at 10:11
  • $\begingroup$ That's correct, but overall it's easier to use the same first layer height/settings on every print profile so you don't have to fiddle around with different z offsets, especially for a beginner. A 0.2 mm first layer is more forgiving than a 0.1 mm first layer. $\endgroup$
    – Maaarsl
    Dec 17 '20 at 10:35
  • $\begingroup$ Yes 0.2 mm first layer is more forgiving, I'm totally with you, e.g. the default initial layer in Cura is also larger than the rest of the layers. This makes it usually much more easy to stick, I'm only falling over the reasoning about the squishing. :-) Welcome to 3DPrinting.SE! $\endgroup$
    – 0scar
    Dec 17 '20 at 12:30
  • $\begingroup$ Thank you :) I'm not a native english speaker and may have chosen the wrong words to describe what i meant. While reading Calvins question I assumed that he is a beginner to 3D printing and he just switched the print profile to 0.1 mm without setting a proper/precise z offset which leads to a first layer, which is not squished enough. I just realized this question is 2 years old. When I joined this community yesterday the question was on the 'Active Top Questions' section. Now I'm a little bit confused :S $\endgroup$
    – Maaarsl
    Dec 17 '20 at 23:55
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Basically you have 2 issues, first, an adhesion in combination with layer thickness problem, second, an infill problem.

Starting with the infill issue, when you lower the layer height, without increasing the amount of layers for the "Top/Bottom Thickness", you get a very thin shell (unless the top bottom thickness is expressed in mm). A lower layer height should, because of the lesser amount of filament being extruded over the infill, should be accompanied with a higher infill value, but that is necessary for the top layers, your issue is with the bottom layer and adhesion. As said, a lower layer height also implies lower filament flow, for the first layer this lower flow causes an inconsistent flow to adhere the filament to the bed (probably caused by the gap between the nozzle and bed from leveling with a piece of paper). Most slicers will add some extra features to increase the change to get the filament to stick to the bed; one of those is an increased first layer height (e.g. in Ultimaker Cura, the first default layer height for Ultimaker 3 printers is laarger than the rest of the layers), others include modifying the flow by e.g. over-extruding for the first layer.

You could try to increase your first layer height to the value you create successful prints with, specify the thickness of the bottom and top (or increase the amount of layers for printing these) and increase the infill percentage.

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