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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

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

And, of course, everything fails afterwards.

Any help is appreciated. Thanks in advance.

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  • $\begingroup$ Are you using herringbone gears? I'm trying to see why the angle changes. $\endgroup$ – cmm Jul 15 '19 at 19:04
  • $\begingroup$ 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. $\endgroup$ – stefanu Jul 16 '19 at 14:03
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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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  • $\begingroup$ Thank you for your response. I'm going to accept the answer because it solves the problem, even if I still cannot pinpoint the cause of the problem. $\endgroup$ – stefanu Jul 25 '19 at 12:00

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