<p>I don't know how to explain how the problem is occurring with the STL post-processing tools you are using.  </p>

<p>Try loading the STL directly into a slicer and view the result, then slice and view the toolpath.  It is always helpful to eliminate steps in an attempt to narrow down where the problem is generated.</p>

<p>Were I to try to patch the OpenSCAD model, I would create a hub component that overlays where the crack is found.  This would be small cylinder with a hole that overlays the hub.</p>

<p>I have had success adding elements and holes to existing OpenSCAD models and imported STL files using OpenSCAD.</p>

CC BY-SA 4.0
2019-07-16T14:41:19.997Z
2019-07-16T14:41:19.997Z
cmm
<p>Goal : create a pair of bevel gears for 90 degrees angle axles.</p>

<p>Context : the gears are designed with an OpenSCAD library (<a href="https://www.thingiverse.com/thing:1604369" rel="nofollow noreferrer">https://www.thingiverse.com/thing:1604369</a>, function 'pfeilkegelradpaar'), then I try to modify them using TinkerCAD.</p>

<p>The problem : When printing the STL exported from OpenSCAD, everything seems fine. But when I import the STL in TinkerCAD, there is a separation where the angle changes, and I cannot seem to find a configuration that works.</p>

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

<p>Also, when previewing with Cura (tried with the older v14 as well as the latest v4), I get the same behavior : the exported STL creates a solid object, while the STL from TinkerCAD (even if not modified, just imported and exported) has a 'gap' of about 8 layers.</p>

<p><a href="https://i.sstatic.net/S5ioP.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/S5ioP.png" alt="enter image description here"></a></p>

<p>And, of course, everything fails afterwards.</p>

<p>Any help is appreciated. Thanks in advance.</p>

CC BY-SA 4.0
2019-07-15T19:04:00.640Z
Are you using herringbone gears?  I'm trying to see why the angle changes.
cmm
CC BY-SA 4.0
2019-07-16T14:03:33.773Z
Yes, there is a 20-degree angle; it's one of the parameters of the OpenSCAD library.
But even with no angles, the problem persists; probably because the library creates the gear in two parts.
stefanu
<ultimaker-cura><3d-design><slicing>
Bevel gears 3D model
stefanu
# Bevel gears 3D model

(Asked by: username_0 on 2019-07-15)

Goal : create a pair of bevel gears for 90 degrees angle axles.

Context : the gears are designed with an OpenSCAD library (<https://www.thingiverse.com/thing:1604369>, function 'pfeilkegelradpaar'), then I try to modify them using TinkerCAD.

The problem : When printing the STL exported from OpenSCAD, everything seems fine. But when I import the STL in TinkerCAD, there is a separation where the angle changes, and I cannot seem to find a configuration that works.

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

Also, when previewing with Cura (tried with the older v14 as well as the latest v4), I get the same behavior : the exported STL creates a solid object, while the STL from TinkerCAD (even if not modified, just imported and exported) has a 'gap' of about 8 layers.

[![enter image description here](https://i.sstatic.net/S5ioP.png)](https://i.sstatic.net/S5ioP.png)

And, of course, everything fails afterwards.

Any help is appreciated. Thanks in advance.

**Tags:** ultimaker-cura, 3d-design, slicing
> **Comments:**
> **username_1**: Are you using herringbone gears?  I'm trying to see why the angle changes.  
> **username_0**: Yes, there is a 20-degree angle; it's one of the parameters of the OpenSCAD library. But even with no angles, the problem persists; probably because the library creates the gear in two parts.  

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## 1 answers

### Answer by username_1 on 2019-07-16. Score: 1 | Accepted answer

I don't know how to explain how the problem is occurring with the STL post-processing tools you are using.

Try loading the STL directly into a slicer and view the result, then slice and view the toolpath. It is always helpful to eliminate steps in an attempt to narrow down where the problem is generated.

Were I to try to patch the OpenSCAD model, I would create a hub component that overlays where the crack is found. This would be small cylinder with a hole that overlays the hub.

I have had success adding elements and holes to existing OpenSCAD models and imported STL files using OpenSCAD.


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