Turn an edge in sheet metal part

[Anonymous]

Is there a way to get a true flat pattern of part that has flange on radiused or curved edge? See the attached part file... it's a radiused rectangular elbow cheek with a 0.25" turned edge along the heel and throat to allow for a pittsburgh lock. I made the part using the Contour Roll command which doesn't make anything close to a correct flat pattern.

From what I've seen Inventor doesn't know how to flatten a "deformed" part, but I thought I'd ask anyway to see if someone has found a work around. I know that the actual part/material will stretch; however, it's a common practice in light-gauge sheet metal (specifically ductwork) to add around a 0.25" to the extents of the radiused/curved portion of the flat pattern and use a turning machine to form the flange.

[CCarreiras]

Hi!!

No, it's not possible Inventor calculate this Flat Pattern.

This is a Plastic Deformation, not bending.

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[Anonymous]

Thanks. I know this isn't straight forward bending/rolling, but it is a fundamental sheet metal feature. If I were to make the heel or throat of this elbow and place 0.25" flanges along the curved sides (instead of forming the pittsburgh lock), I would be able to create a flat pattern. And I know from experience that with small flanges (depending on metal thickness), I can roll the heel/throat with minimal distortion in the flanges. It just doesn't seem right that Inventor assumes how to unfold a contour roll in one instance that is correct, but absolutely failes in another instance.

In any event, I'm just looking to find out if anyone has a work around to not only model the part correctly, but also get a correct flat pattern. Possibly by having certain features suppressed or something?