Cut Normal Changes Part Orientation

[Kennco]

Hello,

Does anyone know why this part changes orientation with respect to the origin when the cut is toggled on as normal?

I see no reason why it does so other than something screwy with having a curved surface being cut.  Hopefully the attachment works.

The part was made by doing a contour flange from a profile, to make something similar to a plow, then I was attempting to add a normal cut in order to have a matching right and left.  No matter how I add the normal cut, the part shifts with respect to the part planes.

[JDMather]

Examine the Flat Pattern in wireframe Visual Style with the Cut Normal unchecked and with it checked.

Do you see the difference?

An alternative would be to model the part as a trimmed surface extrusion and then Thicken.

[Kennco]

That doesn't address the basic issue of a cut normal changing the orientation of the part itself, both in the part and in any assemblies made with it. As far as I can tell this happens with any curved contour flange.  With a cut on a plane that is not perpendicular to the surface being cut.

[CCarreiras]

Hi!

Because you deleted solid where the center point was projected in previous operations, and somehow,the software need some anchor point, but it was removed by the cut, so the software create a new ucs. You are lucky, because lots of times Inventor asl you to create a new one 🙂 .

It's not normal, but sometimes it happens. It's kind of a bug.

I think also that this normal cuts use some kind of unfold/Refold operation, and sometimes this Unfold doest work so well and we have to do the refold manually, maybe that's it also. But that's ok, after all you create your part!!

Workaround: Change your UCS for the other side, the uncuted one.

Did you find this reply helpful ? If so, use the    Accept as Solution or Kudos - Thank you!

[Kennco]

Redefined part to have a workplane that is parallel to the XY plane on the opposite end of sketch 2, redefined contour flange to use this new plane. Normal cut on other end of the part still causes it to shift orientation.

I'll just have to have the cut be non-normal and then unfold and cut the excess off, and remember this for all the other variations of this part we have due for modeling.

Thanks for giving me something else to try, even if it still has the same result.

[rdyson]

Or create a new UCS based on the new orientation and use it in your iam and drawings
But I agree, it does not look right

[Kennco]

I don't care about it not looking right, the shift in orientation affects the fit in assembly, since my nice 33 degree cut is now 33.32, which changes all the lengths of every other part in my assembly, as well as causing it to go over shipping width.

[JDMather]

Will the attached file solve your problem?

Are you using Origin to constrain in the assembly or the geometry of the part?

[Kennco]

It's a work-around that's more complex and time consuming than doing an unfold and cutting the excess off while using a non-normal cut, but thanks for your time.

As I said in my original post: I wanted to know why this happens with normal cuts, because I thought I had done something wrong.

The upshot here is that the program actually changes the angle of the cut if you turn on cut normal, and it doesn't matter which plane you use for making the oblique cut. Which really makes creating parts that are going to be rolled more difficult. Still faster than the fabrication guys hand torching out a piece of pipe to make the oblique cut.

Oh well, another broken thing with cut normal.

[JDMather]

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@Kennco wrote:
It's a work-around that's more complex and time consuming than doing an unfold and cutting the excess off while using a non-normal cut,...

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...

Can you post solution using this simpler/faster technique?

[Kennco]

I have custom sheet metal templates created for different steel thicknesses, so switching to part and doing extra processes there, then switching back to sheet metal is a bit more time consuming.  Opinions will vary.

Plus this way I can directly make use of adaptivity in my assembly, should the angle needed change.

[mercerc]

You haven’t stated which version of Inventor you’re using but in listing the properties it was 2015.

I’ve edited your file as well as recreating the file from scratch and the coordinate system for the file didn’t change in any scenario I tested. It looks like this file was created in an assembly did the last cut remove any assembly constraints you may have previously applied? This would be the only answer I would have at this time.

Please check to see you have update2 for Inventor 2015 applied. I tested this in both update1 and update2.

[Kennco]

Constraints in the assembly were from the origin planes. No constraints removed.  Autodesk Application Manager showed all updates installed, but apparently Inventor service packs aren't tracked by the Application Manager.  Manually installed service pack 2 and recreated part from scratch and the same exact error occurs when cut normal is applied.  Created from scratch version of the file is attached.

My apologies for not stating which version of Inventor I had, forgot to do so.

[steve_lindley · Accepted solution]

To anyone still finding this thread in their searches,  (I have found this to be an issue still), but I see Autodesk listed this work around and thought it should be shared here....

https://knowledge.autodesk.com/support/inventor-products/troubleshooting/caas/sfdcarticles/sfdcartic...