<p>I re-printed the model using Curas overlay settings and some stretched cubes to apply different settings to some of the fan blades:
<a href="https://i.sstatic.net/BDVFF.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/BDVFF.png" alt="enter image description here" /></a>
And once printed, the blade seen here at the very bottom looks like it was the best:
<a href="https://i.sstatic.net/g2Htt.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/g2Htt.jpg" alt="enter image description here" /></a>
The changes on that blade were just 4 bottom layers, 0 top layers and 7 walls (effectively making everything after the bottom 4 layers 100% density with just walls).</p>
<p>I'm not sure why exactly the gap between the top layers and the walls was showing up, but regardless, this seems to be the fix.</p>

CC BY-SA 4.0
2023-12-28T17:02:25.503Z
2023-12-28T17:02:25.503Z
J H
<p>I'm working on printing the <a href="https://cults3d.com/en/3d-model/various/3d-printable-jet-engine-minimal-printing-supports" rel="nofollow noreferrer">3D Printable Jet Engine w/ Minimal Printing Supports</a> and I'm having a surprising amount of difficulty printing the fan. The fan seems to print fine, right up until the last 20 or so layers, where it starts to gap and blob-like I've never seen before.</p>
<p>I have quite a few photos <a href="https://imgur.com/a/9Cgmu9F" rel="nofollow noreferrer">available to view</a>, but I'm including a few below:</p>
<p><a href="https://i.sstatic.net/2xGC2.jpg" rel="nofollow noreferrer" title="Photo of jet engine fan model with gaps and blobs"><img src="https://i.sstatic.net/2xGC2.jpg" alt="Photo of jet engine fan model with gaps and blobs" title="Photo of jet engine fan model with gaps and blobs" /></a></p>
<p><a href="https://i.sstatic.net/v5SuC.jpg" rel="nofollow noreferrer" title="Upclose photo of the same fan model"><img src="https://i.sstatic.net/v5SuC.jpg" alt="Upclose photo of the same fan model" title="Upclose photo of the same fan model" /></a></p>
<p>Settings/components:</p>
<ul>
<li>Ender 3 S1 Pro (running Klipper)</li>
<li>Filaments tried: <a href="https://rads.stackoverflow.com/amzn/click/com/B0B5Z221QB" rel="nofollow noreferrer" rel="nofollow noreferrer">SUNLU 3D Printer Silk PLA Filament 1.75 mm</a> and <a href="https://rads.stackoverflow.com/amzn/click/com/B0C69HXGWW" rel="nofollow noreferrer" rel="nofollow noreferrer">AMOLEN Shiny Silk Black PLA Filament 1.75 mm</a></li>
<li>Nozzle size: .4 mm</li>
<li>Layer heights: 0.16 mm, 0.2 mm</li>
<li>Speeds: 100 mm/s, 75 mm/s</li>
<li>Temperature: 205 °C, 210 °C, 215 °C</li>
<li>Retraction: Yes, tuned with with retraction towers</li>
<li>Slicer: Cura</li>
</ul>
<p>What I have tried:</p>
<ul>
<li>Initially, I thought that maybe it was because I had the infill set to ~40 %, and a lot of top layers, so maybe the print geometry and the infill/top layers combo caused it, but they showed up when I put the infill to 100 %, as well as if I just put the walls to 20 (thus making it 100 %).</li>
<li>I've tried printing with .20 mm and .16 mm layer height, as well as .16 mm + adaptive layers (which made a lot of it .12 mm)</li>
<li>Tried switching to a different filament, and encountered the same results.</li>
<li>Printed some tuning towers to verify that the temperature and retraction are set up okay.</li>
<li>Tried lowering the speed down to 75 mm/s (usually around 100 mm/s)</li>
</ul>
<p>If it was something like a clogged nozzle, then I would assume that that same pattern would be seen everywhere on the print. That goes for the temperature and retraction as well.</p>

<ultimaker-cura><slicing><filament-quality><layer-shifting>
Encountering some weird layer gaps on the last few lines of a particular print
J H
# Encountering some weird layer gaps on the last few lines of a particular print

(Asked by: username_0 on 2023-12-25)

I'm working on printing the [3D Printable Jet Engine w/ Minimal Printing Supports](https://cults3d.com/en/3d-model/various/3d-printable-jet-engine-minimal-printing-supports) and I'm having a surprising amount of difficulty printing the fan. The fan seems to print fine, right up until the last 20 or so layers, where it starts to gap and blob-like I've never seen before.

I have quite a few photos [available to view](https://imgur.com/a/9Cgmu9F), but I'm including a few below:

[![Photo of jet engine fan model with gaps and blobs](https://i.sstatic.net/2xGC2.jpg "Photo of jet engine fan model with gaps and blobs")](https://i.sstatic.net/2xGC2.jpg "Photo of jet engine fan model with gaps and blobs")

[![Upclose photo of the same fan model](https://i.sstatic.net/v5SuC.jpg "Upclose photo of the same fan model")](https://i.sstatic.net/v5SuC.jpg "Upclose photo of the same fan model")

Settings/components:

* Ender 3 S1 Pro (running Klipper)
* Filaments tried: [SUNLU 3D Printer Silk PLA Filament 1.75 mm](https://rads.stackoverflow.com/amzn/click/com/B0B5Z221QB) and [AMOLEN Shiny Silk Black PLA Filament 1.75 mm](https://rads.stackoverflow.com/amzn/click/com/B0C69HXGWW)
* Nozzle size: .4 mm
* Layer heights: 0.16 mm, 0.2 mm
* Speeds: 100 mm/s, 75 mm/s
* Temperature: 205 °C, 210 °C, 215 °C
* Retraction: Yes, tuned with with retraction towers
* Slicer: Cura

What I have tried:

* Initially, I thought that maybe it was because I had the infill set to ~40 %, and a lot of top layers, so maybe the print geometry and the infill/top layers combo caused it, but they showed up when I put the infill to 100 %, as well as if I just put the walls to 20 (thus making it 100 %).
* I've tried printing with .20 mm and .16 mm layer height, as well as .16 mm + adaptive layers (which made a lot of it .12 mm)
* Tried switching to a different filament, and encountered the same results.
* Printed some tuning towers to verify that the temperature and retraction are set up okay.
* Tried lowering the speed down to 75 mm/s (usually around 100 mm/s)

If it was something like a clogged nozzle, then I would assume that that same pattern would be seen everywhere on the print. That goes for the temperature and retraction as well.

**Tags:** ultimaker-cura, slicing, filament-quality, layer-shifting

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## 1 answers

### Answer by username_0 on 2023-12-28. Score: 1 | Accepted answer

I re-printed the model using Curas overlay settings and some stretched cubes to apply different settings to some of the fan blades:
[![enter image description here](https://i.sstatic.net/BDVFF.png)](https://i.sstatic.net/BDVFF.png)
And once printed, the blade seen here at the very bottom looks like it was the best:
[![enter image description here](https://i.sstatic.net/g2Htt.jpg)](https://i.sstatic.net/g2Htt.jpg)
The changes on that blade were just 4 bottom layers, 0 top layers and 7 walls (effectively making everything after the bottom 4 layers 100% density with just walls).

I'm not sure why exactly the gap between the top layers and the walls was showing up, but regardless, this seems to be the fix.


---

