topic Re: Turning/Mill - Unwrap Cyclic geometry in Machining Discussions Forum

Turning/Mill - Unwrap Cyclic geometry

CCarreiras — Wed, 04 Feb 2026 16:39:56 GMT

Hi!

It's possible to machine this curved groove in a turning/mill setup?

I'm not a pro on CAM but...
I tried to use 2D contour, but there's a cyclic geometry error...

Part attached if you want to give it a try.

Thank you!

Re: Turning/Mill - Unwrap Cyclic geometry

kacper.suchomski — Mon, 09 Feb 2026 16:33:07 GMT

Hi Carlos

This is a very old and annoying limitation.

Unlike Fusion, Inventor CAM doesn't support "boundless" wrapped pockets.

In Inventor, a pocket must have an end (the start can be open).

If we assume that the part is symmetrical, we can blind the fragments and use the symmetrical pattern in path programming.

We can use an additional model state for this purpose.

For a non-symmetrical part, you'll need two additional model states (or two solids or surfaces, depending on the geometry range).

Either way, preparing the solid for toolpath creation requires additional modeling.

Once you have your model ready, a wrapped 2D pocket should do the trick.

(view in My Videos)

Re: Turning/Mill - Unwrap Cyclic geometry

CCarreiras — Tue, 10 Feb 2026 10:30:18 GMT

Hi @kacper.suchomski , nice Workaround!

In Fusion is possible to do that part without the workaround?

Re: Turning/Mill - Unwrap Cyclic geometry

kacper.suchomski — Tue, 10 Feb 2026 10:58:51 GMT

@CCarreiras wrote:

In Fusion is possible to do that part without the workaround?

Yes, but I don't have access to these tools.

https://help.autodesk.com/view/fusion360/ENU/?guid=MFG-MULTI-AXIS-ROTARY-CONTOUR-READ

https://help.autodesk.com/view/fusion360/ENU/?guid=MFG-MULTI-AXIS-ROTARY-POCKET-READ

Re: Turning/Mill - Unwrap Cyclic geometry

kacper.suchomski — Tue, 10 Feb 2026 18:20:07 GMT

In Inventor, you don't have to interfere with the geometry itself, but it still involves additional work.

If you calculate the geometry correctly, the second operation can skip the tool insertion using the helix to avoid wasting machining time and start with a full depth.

(view in My Videos)