Creating a Sharp Fold

[sinus19]

Hello,

I am trying to fold a sheet into an "L" shape (using the the Fold command) but i would like to have the inside of the bend to be sharp and not a radius like on the outside. Is there any way that i can achieve this?

[jletcher]

The only thing is .001 radius...

[sathersc23]

The inner bend radius and outer bend radius are tied together like they would be in real life. You can try setting yoru bend radius to nearly zero (I've never tried) and see what that does for you. Most things in life though that are folded have a bend radius of something to it. If you're forming a piece using a different process, you probably want to try a different modeling method.

[sathersc23]

To pre-empt the next common question (that I asked once myself), there are no "standard radiuses" to fold to or design with, it depends entirely on your tooling and material. If you're doing thin sheet over a break, try 1/16 or 1/32 radius, if you're doing 1.25" steel try 2-3 inches.

Furthermore the k-factor is the ratio of the neutral axis of the bend (grab a mechanics book for that one) from the bend surface across the part thickness.

[sinus19]

Oh I see... Well at the shop we have a hydraulic break that uses sharped end dies and when it bends a sheet it leaves a sharp crest on the inside but a round bend on the outside. Where/how can i change the setting for the radius?

[sinus19]

oh wait i got it! never mind. Thanks guys for the tips.

[JDMather · Accepted solution]

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@sinus19 wrote:
.... Well at the shop we have a hydraulic break that uses sharped end dies and when it bends a sheet it leaves a sharp crest on the inside but a round bend on the outside.

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No matter how sharp it is - there is still an inside radius.
Check the resulting part on an optical comparitor or under microscope.

[blair]

We had really sharp dies on our hydraulic press in the shop, the damage that can occur when someone wants a sharp inside radius will "cut/score" the material. I have never found this to be a good thing.

[jeanchile]

As another comment/side note on this issue, if this is a structural part made from steel the AISC publishes a minimum inside radius for cold bending. Any smaller than this and the part is prone to cracking and yielding. Have no idea if this is what you are doing, just thought I would add my two cents along the lines of what blair was mentioning in hopes that you (or someone else later) doesn't overlook something. Good luck!