Sheet Metal Design

[NK_CAD]

I am tring to unbend with swept blend, does anyone know where is the problem?

[tbraxton]

Hard to tell from the picture but I suspect that the geometry of your swept blend is not a developable surface and therefore Creo will not flatten it in sheet metal. You can check this by looking at the Gaussian curvature analysis of the surface in question.

A developable surface is a smooth surface with zero Gaussian curvature. That is, it is a surface that can be flattened onto a plane without distortion.

[NK_CAD]

Thanks for the reply, but this shape of Swept blend (even that seems easy doesn't follow) the unbend (half of the shape unbended) the other not, even that i tried with sketched rip still the problem is there.

[StephenW]

I agree with tbraxton. You can use surface flatten for just a surface instead of sheetmetal for more complicated parts.

Sheetmetal isn't doing anything special other than applying a bend allowance based on machinery handbook calculation.

The K-factor (or y-factor) is a variable that if you haven't changed is .5 or bend centerline. During forming operations, this value is likely not correct.

The value you use would be based on the forming operation and material used to bend the parts. Usually your manufacturing or vendor can help you with that value.

[NK_CAD]

Thanks, but doesn't work even that 😞

[tbraxton]

Use the Gaussian curvature analysis tool in Creo and post a screen shot of the surfaces in question with the Gaussian curvature displayed. It most likely will show you why you are not able to flatten this.

[StephenW]

You can also zip the file and post it here. Please include what version of creo you are using.

It really is impossible to diagnose based on the picture.

Based on what I see is there is a "twist" in the surface, but again, it's difficult to tell from just a picture.

My exagerrated image is below.

The curvature analysis tool that @tbraxton mentioned is under the analysis tab curvature.

[NK_CAD]

Thanks, for directions, but not so comfortable to work with curvation, i have attached the file, so maybe you have a quickly idea for unbend it...really appreciate in any case 🙂

[StephenW]

@NK_CAD 

It's definitely the "twist" you have in the part.

I do sheet metal sometimes and as this is, this is not something that can be done from the standpoint of how the sheet metal module works.

With respect to how surface flatten works, maybe someone else can help. I don't know how to do that on your part. Maybe @tbraxton 

It may be helpful if you show what you are trying to accomplish with the part and someone can guide you in a better direction.

[NK_CAD]

I understand, seems that not so easy to implement thats why i did it diferently with flat and extrude cut, means that i change the design from swept to simply flat with angle , as you can see in the screen shot, but thanks for the time and efforts.