topic Re: Fillet weld issue in Inventor Forum

Fillet weld issue

Stephen__Hall — Thu, 02 Apr 2026 08:06:29 GMT

I'd like to create a fillet weld around the outside of this tube, but the only result I get is around the inside, as the attached image shows.

However, if I manipulate the tube so that one side is flat, I get the desired result. therefore proving that it can be done. the question is how do I achieve this with the fully formed tube?

Re: Fillet weld issue

Ihor_Radikhovskyi — Thu, 02 Apr 2026 09:18:38 GMT

Hi,

The behavior you're seeing is due to how the Fillet Weld tool interprets the joint between curved surfaces.

In this case, the tube is fully round, so there is no clearly defined external corner. The algorithm detects the smallest angle between faces, which results in the weld being created on the inside rather than the outside.

That’s why modifying the tube to have a flat face works — it introduces a well-defined external edge, allowing the weld to be placed correctly.

Possible solutions:

- Use Weld Bead instead of Fillet Weld for better control over placement
- Split the contact area (Split Face) to create a clear edge for the weld
- Manually model the weld (e.g., Sweep along a path) if precise control is required

This is a limitation of fillet weld definition on curved geometry rather than a modeling error.

Re: Fillet weld issue

Stephen__Hall — Thu, 02 Apr 2026 09:21:59 GMT

Thank you, that's great information.