Bend non-planar geometry

[Zestje]

Hello,

I would like to bend a part which is not planar. The basic shape has a straight section and a circular section (blue shape in the picture with the yellow contour (centerline)). This state represents the assembled state on an 'oversize' other part. When manufacturing the part it will look a little different. In particular the circular section has a smaller radius. My model is that of the deformed (assembled) state. I also have the contour of the non-deformed (manufactured) state: a sketched curve in side view, the red contour in the picture (unfortunately I cannot post a picture now). Is there a way to convert / bend / transform the deformed state (source geometry) into the non-deformed state by using the known non-deformed contour?

This will not work with spinal bend, because the source shape is not planar. Maybe I could somehow 'unwind' the source geometry to be planar and 'rewind' it on the new contour? I have tried many things, but nothing comes even close to what I want. Any help is appreciated!

 

[dross]

Looks like a sweep will work for you.

 

[srieger]

Best bet is to do it as a sweep, Make and instance that removes the bends at the tangent. Use a curve through the center and create an analysis feature to calculate the length of the bent components. Add the stretch for all bends. Then make a straight attached to the end with the length derived from the previous value.

 

[Zestje]

Best bet is to do it as a sweep, Make and instance that removes the bends at the tangent. Use a curve through the center and create an analysis feature to calculate the length of the bent components. Add the stretch for all bends. Then make a straight attached to the end with the length derived from the previous value.

For the basis shape I think a sweep would work, but the real geometry actually is complex, with several cutouts different wall thicknesses and other features.
But what do you mean by 'Add the stretch for all bends'?

 

[srieger]

But what do you mean by 'Add the stretch for all bends'?

You cannot unbend accurately a non planar feature because it's not linear.

Materials don't bend like a piece of string. There is a neutral line in which the material is linear but this is rarely if ever at the center of the feature. So, this being the case, the material will stretch during a bend due to the inner radius having to compress (which it doesn't like to do). So, you end up with too much material after the bend.

You can figure this out by trial and error if you do the manufacturing. For tubing there tends to be a linear stretch per degree and a non-linear stretch. It gets a bit complicated but it's pretty consistent with a particular material, size, wall thickness and tooling set.

With that you subtract the stretch from the overall linear blank length to get a blank size that will be right for the finished part.

 

[Zestje]

You cannot unbend accurately a non planar feature because it's not linear.

Materials don't bend like a piece of string. There is a neutral line in which the material is linear but this is rarely if ever at the center of the feature. So, this being the case, the material will stretch during a bend due to the inner radius having to compress (which it doesn't like to do). So, you end up with too much material after the bend.

You can figure this out by trial and error if you do the manufacturing. For tubing there tends to be a linear stretch per degree and a non-linear stretch. It gets a bit complicated but it's pretty consistent with a particular material, size, wall thickness and tooling set.

With that you subtract the stretch from the overall linear blank length to get a blank size that will be right for the finished part.

Thanks for the elaboration. I'm familiar with the concept of 'neutral line' when bending a part, I just didn't understand that was what you meant.
For (simple) sheet metal parts fortunately there are useful formula and bend tables, but for (complex) plastic parts unfortunately there often is trial and error involved or simulations are required...