Sheet Metal Corner Round does not flatten properly

[chrisw01a]

Does anyone know why on a rolled sheet metal part, the corner round feature does not flatten out properly?

In the past we have used the old "delete face & thicken" trick, but this has to be done manually if you have a pattern that changes dynamically like we do.

I am trying to get away from delete face since it requires more time and manual intervention.

Attached is the part in question and example images.

The reason this is a problem is because when this flat pattern is used by other programs, it creates issues.

Anyone have any ideas how to fix this?

Thank you for your help!

[chrisw01a]

If you go to the flat pattern and zoom in tight to the corner, you can see that there are 2 "arcs" where there should only be 1.

[bob_holland]

@chrisw01a

I see what you mean.

It is kind of like there is a draft angle

It is even worse with a Chamfer.

Thank you for bringing this to our attention.

I will be sending this to our development staff.

Bob Holland

[bob_holland · Accepted solution]

@chrisw01a

Thank you for bringing this to my attention and we are sorry for your inconvenience.
I have sent this to our development staff for them to resolve..

I have created a web page and the investigation have been documented in the article published here:

http://knowledge.autodesk.com/article/Sheet-Metal-Corner-Round-does-not-flatten-properly

We will keep the article updated with the findings from the investigation, as they become available. You may look up the article by searching the Autodesk Knowledge Network using the Incident Id: 167616 for the status of the investigation any time.

The above webpage should be live by Monday morning PST.

Thank you for your patience and I look forward to hearing from you soon.

[chrisw01a]

Bob,

I am very pleased to know that you have documented this.

I have uncovered some "bugs" with the "cut normal" option in the sheet metal "cut" feature that I would really appreciate some help with.

There are a couple of particular parts that have been a thorn in my side for 14 years and the cut normal feature would save me hours upon hours of extra time each year IF it worked properly.

Please let me know how I can contact you to get you the information.  If you would like, I can send you a link to a post with examples...

Here is what the part should look like... 

And here is is after the "cut normal" is applied

 

There are other issues on this but this was just a quick example.

Once again, thank you.

Chris

[WHolzwarth]

Hmm. IMO, corner rounds and corner chamfers can only work right by theory on plain surfaces, not cylindrical ones. If a corner round on a cylindrical surface is needed, then an Unfold-Refold should be done, and the corner round or chamfer be applied on the flattened sheet.

I've placed a sample (2017) in Chris's file with the red corner round. As can be seen, to three other rounds axes can be set. That's nice, but not ok in theory.

On the other hand, no axis can be set at the red round.

Perhaps sometimes that's no good, but the benefit of these rounds is the perfect Flatpattern.

Walter

Another issue: These corner round axes are more like a fake. They should be meeting in a single point of the center axis, but they don't.

[chrisw01a]

I see what you mean.  Will experiment...

[IgorMir]

Thank you, Walter.

That in turn might lead us to re-think the modeling practice a bit. So, if Unfold is used - then in there all the filleting/chamfering should be introduced prior to Refold. That way the final Flat Pattern will be free from unwanted extra lines in corners.

Cheers,

Igor.

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@WHolzwarth wrote:

Hmm. IMO, corner rounds and corner chamfers can only work right by theory on plain surfaces, not cylindrical ones. If a corner round on a cylindrical surface is needed, then an Unfold-Refold should be done, and the corner round or chamfer be applied on the flattened sheet.

I've placed a sample (2017) in Chris's file with the red corner round. As can be seen, to three other rounds axes can be set. That's nice, but not ok in theory.

On the other hand, no axis can be set at the red round.

Perhaps sometimes that's no good, but the benefit of these rounds is the perfect Flatpattern.

Walter

Another issue: These corner round axes are more like a fake. They should be meeting in a single point of the center axis, but they don't.

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