topic Re: Unwrap command create multiple extrusions on a flat surface in Inventor Forum

Unwrap command create multiple extrusions on a flat surface

R.nnie — Wed, 12 Oct 2022 11:58:15 GMT

As a new user I'd like to know if it is possible to create a sketch and extrude (hole in my example) on an unwrapped surface. I would like that feature to then translate directly to my main design (a rolled cylinder).
Is this option possible in Inventor?
I have attached an example pic.

For this design I have to make multiple holes in the rolled cylinder using angled planes, always at a different location depending on the model. If I could just wrap this sketch around the surface and using either extrude or hole command remove the material in the cylinder it would save me a good bit of time.
Thanks!

Re: Unwrap command create multiple extrusions on a flat surface

JDMather — Wed, 12 Oct 2022 12:05:27 GMT

Unwrap is not the correct technique for this - you should be using Sheet Metal Unfold/Refold for this (even if the material is not metal).

What version of Inventor are you using?

Re: Unwrap command create multiple extrusions on a flat surface

blandb — Wed, 12 Oct 2022 13:02:47 GMT

as @JDMather mentioned, utilizing the Unfold/refold will allow you to temporarily flatten a part to place features as needed. Please see attached video as an example.

Re: Unwrap command create multiple extrusions on a flat surface

R.nnie — Thu, 13 Oct 2022 08:36:56 GMT

Thanks! I've tried this way and it seems to work fine. However, my holes are not dimensionally accurate once the shell is refolded so I'm back to square one with the design.

Re: Unwrap command create multiple extrusions on a flat surface

JDMather — Thu, 13 Oct 2022 10:48:26 GMT

@R.nnie wrote:

However, my holes are not dimensionally accurate…

@R.nnie
What exactly do you mean by this? (I know what you mean - but I am trying to walk you through a thought experiment.)

In the real world shapes can be cut after bending or before bending.
Any shapes cut before bending will be distorted by the bending process.

So you have to define:

1. Will the cut be performed before bending or after bending.

2. What is the desired geometry AFTER bending?

With these two parameters known - the correct modeling technique can be given.

Attach the *.ipt of your closest attempt at achieving your true Design Intent here and end all doubt.

Re: Unwrap command create multiple extrusions on a flat surface

R.nnie — Fri, 14 Oct 2022 10:18:32 GMT

I am trying to automate the process of hole creation in a pressure vessel, the holes will be cut after the material is refolded.

I know that sheet metal might not be the best option here, but I can compute the parameters in 2D and link my excel spreadsheet to create the nozzle holes. Otherwise, I have to create a plane, point and a hole for each nozzle possibility, and this can amount to as much as 20 plane and hole combinations.
I am just trying to see if this could be a feasible alternative however now it looks like I have to correct for the hole dimension due to the refolding action.

Re: Unwrap command create multiple extrusions on a flat surface

JDMather — Sun, 16 Oct 2022 11:59:59 GMT

@R.nnie

What version of Inventor are you using (can you Attach an example file).

I think that I might have a technique for automating the process in a logical way.