Thin part: sheet metal or not sheet metal

[akelly]

We have an existing part made from sheet metal.  I'm stumped whether or not it's a Creo "sheet metal" part.  I've watched some tutorials and none of them seem to be close to this use case.  I'd rather not have to make punches and dies.

Also, as a sheet metal part, I can't figure out how to model to the finished dimensions without creating dummy waste material with dummy dimensions that you have to get rid of at the end of the model.  Seems like poor Creo practice.

As a solid part, you could brute-force this as a single revolve feature.  It's bordering on poor practice having that many segments in the sketch.  Ideally there's a "better" way?

If you try to use a thin feature instead of a solid feature, the dimensioning scheme doesn't work.  Some dimensions are to the inside surface while others are to the outside surface. 

Also, I hate flexible modeling.  You should be able to do this in either as a solid part or sheet metal part on their own.

Sorry for the bad sketch.  It's a round part - I sketched a half section.

[KenFarley]

Judging from the sketch I'd say it was likely punched in a progressive die of some sort, Looks like the bottom of a pressurized can, like shaving cream or something like that.  If it was purely a part made from spinning sheet metal or some process like that I'd expect radii at the shorter side of the "U" at the top.

Can't you just ask the person who is making these what the method is? That would settle a lot of things.

Seems like a model of the part is always going to be a bit of an idealization, since you probably won't model any "draw" or thinning of the material due to extruding or deformations, etc.

As for section complexity, I don't understand what you're talking about. 9 entities in a sketch is hardly any. I would model this as a single revolve. It's not "brute-force", it's just straightforward modeling. 

[anursingh]

Hi @akelly,

I wanted to see if you got the help you needed.

If so, please mark the appropriate reply as the Accepted Solution. It will help other members who may have the same question.
Of course, if you have more to share on your issue, please pursue the conversation. 

Thanks,
Anurag 
 

[ByDesign · Accepted solution]

I understand the hiccups of both inside and outside dimensions on thin parts. I often use lines of equal length (even if they are construction geometry) so you don't have to have extra dimensions.

I agree with @KenFarley that this won't be a true model because there is no way to "form" it from sheet without some thinning or material movement - especially near the "square" corners. I doubt they can be square corners in practice. Anyway, you can show it certainly as an approximation. And, you can use the primary surface for creating your dies.

As for Sheetmetal, you won't get a good sheetmetal model from Creo, because it can't do compound surfaces. That is a forming operation, which Creo usually fails at - especially since the outer wall is a revolve that is parallel to the axis.

Just make a revolve like @KenFarley said. Thin it if you know how much in what areas to better represent.

Good luck with your project.

[bbrejcha]

If it's a sheet metal part Its always best to do it in the Sheet metal module. Of course we can model anything, it's fabricating it that's often the challenge.  Controlling the geometry w/ the dimensions you want is often relative to how the part is used in assembly.  I tried to think thru the model and understand what your looking for dimensionally using an offset sketch turned construction.  To do this in sketcher you hold shift and right click thru to offset.

I hope I read properly.

Bart Brejcha designengine.com

bart@designengine.com

[akelly]

Even though the real part is made from sheet metal (stamping?  drawing? rolling?), the consensus is that's too hard in Creo.  Everyone suggested a Creo solid part, which matches your screen shots.

[bbrejcha]

Makes sense I suppose if you don't car to flatten the geometry.  I doubt my part would flatten and it's in Sheetmetal

bart brejcha bart@designengine.com