Sheet metal - rip and flatten a 30 deg elbow

[piotrekdoro94]

Hi, I'm trying to rip and flatten a 30 deg elbow so that it can be then cut out of a metal sheet. I could swear I've done this before in the exact same way I'm trying to do it now, but it doesn't work. Could someone help me correct my workflow, because I'm out of ideas. I use Inventor 2016 so I can't create a surface body and use unwrap to flatten it.

I've adjusted sheet metal definition to match the details thickness. I've tried to create an albow with sweep, loft, thicken a surface. I've also tried to create a rip manually or to draw only half and elbow and then flatten it.

I use inventor 2016 so I can't create a surface body and unwrap it because it was introduced in Inventor 2020.

EDIT: I've also tried contour roll. I've managed to create an elbow but the flat pattern doesn't work properly and just gives me a rectangle

[CCarreiras · Accepted solution]

Hi!

You can't achieve a flat pattern from this model.

This model needs a plastic deformation to produce and Inventor does not compute that kind of deformation, Inventor only support bending or calendering.

The Rectangle you get with the contour role is somehow correct, like i said, to produce that part you will need to roll first (the rectangle) and then apply some plastic deformation to get the final form.

[piotrekdoro94]

Thank you, how do I apply plastic deformation to a model? I have a bunch of these kind of parts to draw.

Countour rolled elbow attached.

[kacper.suchomski · Accepted solution]

Hi

The sheet metal module is used to design linear bending, and this model is deformed nonlinearly.

You will have to manually model the interrupts and then use the Unwrap tool. In the meantime, it is best to strip the surface by half its thickness.

Ps. If you are using the 2016 version, there is no help for you.

[piotrekdoro94 · Accepted solution]

All right, I guess It's not worth the hassle to model it. Instead I'm going to just calculate lengths of an inner and outer arch, mark where they are on a piece of 90 deg elbow, tie a piece of string around it and draw the resulting contour around the entire elbow.

[kacper.suchomski]

Make sure you understand the geometry of the flat pattern.

This is not always intuitive for inexperienced people.