ExtrudoWhy is my 3D print gaps or pillowing on top layers?
Gaps or pillowing on top layers is usually caused by not enough solid top layers or infill density to fully close off the top surface. The top surface has small holes, gaps, or a bumpy pillow-like texture instead of being smooth and solid
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Quick reference
| Defect | Most likely cause | First thing to try |
|---|---|---|
| Gaps or pillowing on top layers | Not enough solid top layers or infill density to fully close off the top surface | Increase top layer count |
What it looks like
The top surface has small holes, gaps, or a bumpy pillow-like texture instead of being smooth and solid
Most likely cause
Not enough solid top layers or infill density to fully close off the top surface
How do I fix gaps or pillowing on top layers? Step-by-step
- 1
Increase top layer count
Raise the number of top solid layers in your slicer (try 5-6 layers instead of 3).
Done when: Top surface has no visible gaps or thin spots
- 2
Increase infill density
Raise infill density by 10-15% so the top layers have a firmer base to print onto.
Done when: Infill pattern looks denser in the print preview
- 3
Slow down top layer speed
Reduce the print speed specifically for top solid layers so plastic has time to lay flat.
Done when: Top surface looks smoother and more even
Frequently asked
What causes gaps or pillowing on top layers in 3D prints?
Not enough solid top layers or infill density to fully close off the top surface
How do I fix gaps or pillowing on top layers on my printer?
Follow the step-by-step fix above, starting with "Increase top layer count". Each step includes a "done when" check so you know whether it worked before moving on.
Is this fix confirmed by other makers?
This entry is part of Extrudo's seeded defect library. Confirmation counts appear once real users report the fix worked.
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