Unfold a part to make it flat

dennis_schulz992

Hello!
I would like to ask how I could unfold this part to make it lay flat while manufacturing it?
How would you do that?

nick_papageorge073

I'd probably model it both ways, and have a configuration to switch between "straight" and "bent". You'd have to take educated guesses how much stretch there might be at the hinge. I'd probably use the hinge's neutral plane and keep its length the same in both straight and bent configurations, as a starting point.

Sheetmetal parts can be folded and unfolded. What you have there seems to be a living hinge for a plastic part, so it's not applicable.

dennis_schulz992

Thank you for your response!
So far the only way I see is to really model it twice in both orientations.

You are right is is a plastic part. My problem with doing it twice is that I have to add more features to it and all of this I have to do and maintain twice in this case. That’s not optimal in my opinion.

I already played with that sheet metal folding function but thats not what I need here.

What I would really need is a way to define an axis, define static parts and then tell Onshape to bend that stuff along the axis.

nick_papageorge073

dennis_schulz992 said:

...snip...

What I would really need is a way to define an axis, define static parts and then tell Onshape to bend that stuff along the axis.

I don't believe any CAD system does this that I'm aware of. I came from 20 years of Creo, which is PTC's high end offering, and it did not do that. I don't think even the FEA packages can model this, because it's plastic deformation. (plastic means non-linear in this sentence usage).

Just take your best guess, and make a prototype, then refine your guess based on the prototype. And obviously the prototype part has to be the same material and manufacturing process as the final part, or the living hinge won't react the same way.

martin_kopplow

I'd consider a sheet metal part that emulates the bend and the two tangent faces as helper geometry, add two slabs, then use booleans with "keep tools" to create the complete part. That should do all the math for you.

https://cad.onshape.com/documents/b14b6dbf019046ca7e267a0d/w/213fd3fb58ddbc086e844ba1/e/38b0bef7c400a353df2ea860?renderMode=0&rightPanel=sheetMetalPanel&uiState=6591a708f362903964d2ef2e