<p>Fillets in X-Y plane (i.e. between two vertical surfaces) work great for 3D prints and increase the strength a lot. They usually also improve the print quality, because the print head can keep a constant speed in the curve instead of slowing down to a sharp corner.</p>

<p>However fillets that extend in Z direction (i.e. between a vertical and a horizontal surface) suffer from layer artifacts. Sometimes they can look worse than a sharp corner would. While they do still increase the strength significantly, they are not as strong as similarly sized fillets in X-Y plane are.</p>

CC BY-SA 4.0
2019-06-16T16:13:44.630Z
So the nozzle can keep it's speed around corners better, and X-Y fillets are better than Z fillets. Kewlio.
user77232
CC BY-SA 4.0
2019-06-16T11:16:43.170Z
2019-06-16T11:16:43.170Z
jpa
<p>If your part needs structural support, then the word is: <strong>absolutely</strong>. Fillets provide the added support when you need it. If your part has a meeting line which is sharp - 90° (or perpendicular), there is a natural <a href="https://mechanics.stackexchange.com/q/18183/4152">stress riser</a> in your design. This is a weak spot where a crack can form. If strength is needed and the fillet won't interfere with the design, it's definitely something you should include with your part. </p>

CC BY-SA 4.0
2019-06-16T18:46:48.400Z
Chamfers (flat corner cuts) are a better option for printability, unless the corner is in the XY plane.
Trish
CC BY-SA 4.0
2019-06-18T10:40:15.303Z
@Trish - chamfers are not really any more printable than a fillet In my (admittedly limited) experiance, and they still leave two stress points.
SiHa
CC BY-SA 4.0
2019-06-18T11:38:22.477Z
Please check out [Makers Muse on fillets & chamfers](https://www.youtube.com/watch?v=XTvBOGgx48I).
Trish
CC BY-SA 4.0
2019-11-15T08:03:00.743Z
@SiHa Fillets are less printable than chamfers (depending on the printing plane), please read [this answer](/a/10278).
0scar
CC BY-SA 4.0
2019-06-15T21:15:25.947Z
2019-06-15T21:15:25.947Z
Pᴀᴜʟsᴛᴇʀ2
<p>A fillet is like a rounded corner but on the inside of the corner.</p>

<p><a href="https://i.sstatic.net/XDTnd.png" rel="noreferrer"><img src="https://i.sstatic.net/XDTnd.png" alt="enter image description here"></a></p>

<p>Does it make a difference (structurally) to use fillets on a 3d printed part?</p>

<3d-models>
Should I include fillets on my 3d printed parts?
user77232
# Should I include fillets on my 3d printed parts?

(Asked by: username_0 on 2019-06-15)

A fillet is like a rounded corner but on the inside of the corner.

[![enter image description here](https://i.sstatic.net/XDTnd.png)](https://i.sstatic.net/XDTnd.png)

Does it make a difference (structurally) to use fillets on a 3d printed part?

**Tags:** 3d-models

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## 2 answers

### Answer by username_2 on 2019-06-15. Score: 12 | Accepted answer

If your part needs structural support, then the word is: **absolutely**. Fillets provide the added support when you need it. If your part has a meeting line which is sharp - 90° (or perpendicular), there is a natural [stress riser](https://mechanics.stackexchange.com/q/18183/4152) in your design. This is a weak spot where a crack can form. If strength is needed and the fillet won't interfere with the design, it's definitely something you should include with your part.

> **Comments:**
> **username_3**: Chamfers (flat corner cuts) are a better option for printability, unless the corner is in the XY plane.  
> **username_4**: @Trish - chamfers are not really any more printable than a fillet In my (admittedly limited) experiance, and they still leave two stress points.  
> **username_3**: Please check out [Makers Muse on fillets & chamfers](https://www.youtube.com/watch?v=XTvBOGgx48I).  
> **username_5**: @SiHa Fillets are less printable than chamfers (depending on the printing plane), please read [this answer](/a/10278).  

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### Answer by username_1 on 2019-06-16. Score: 11

Fillets in X-Y plane (i.e. between two vertical surfaces) work great for 3D prints and increase the strength a lot. They usually also improve the print quality, because the print head can keep a constant speed in the curve instead of slowing down to a sharp corner.

However fillets that extend in Z direction (i.e. between a vertical and a horizontal surface) suffer from layer artifacts. Sometimes they can look worse than a sharp corner would. While they do still increase the strength significantly, they are not as strong as similarly sized fillets in X-Y plane are.

> **Comments:**
> **username_0**: So the nozzle can keep it's speed around corners better, and X-Y fillets are better than Z fillets. Kewlio.  

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