NX 7.5 Sheet metal issues

[pamakela]

Hi,

we are using NX 7.5 and it's Sheet Metal module gets heavy use during the current project. As the project has gone onwards, some weird behaviour (bugs?) has come up. Particularly Contour Flanges and Three Bend Corner features tend to cause problems. Sometimes when you do a Contour Flange, it stops working properly even after many features have been created later on after it. I start getting the 'Unable to create body' error - which did not appear the first time you created the feature. Also sometimes the Contour Flange creates overlapping geometry (ie. it won't miter some edges properly) which will not flatten.

We do have newer version of NX available, so if this behaviour is a known bug in 7.5 I can simply request an update. If not - are there certain workarounds or ways of working to avoid these error situations?

 

[deedub777]

Hi pamakela,

There have been updates to the sheet metal application right through NX8.0, 8.5 and NX9 had a major update for three bend corner. If you post some examples of overlapping geometry...
It is always advisable to get the latest release of NX. NX9 is already on 9.0.2 release and considered stable.

 

[pamakela]

I have been using newer versions of NX during other projects and I didn't encounter these issues back then. So maybe it'd be best if I went straight to NX9.

Here is a screenshot of the overlapping flanges:

The overlap is highlighted by the red ellipse. The green ellipse shows proper mitering. The other green ellipse shows proper mitering and proper three corner closure. This overlap did not occur when this part was first made. Then afterwards when work continued, this overlap appeared and now this part won't flatten.

 

[deedub777]

If you can reproduce the error and show it is repeatable, then try it on NX9 - if it still fails submit a fault to GTAC, it will get looked at.
One thing you could try is (just to test), run convert to sheet metal on the part and see if it cleans it up.

 

[deedub777]

by the way, what type of three bend corner are you using? Open, Closed, Circle??, Something else?

 

[pamakela]

Since this product makes use of industrial design - area which I'm also responsible of - I want pristine sheet metal quality on the parts that are visible. Thus I'm using Closed. I could go with Open and have the holes covered afterwards. Or use Open and leave things that way if the customer is happy with this..

Also the way of working might of interest here. I make all of the sheet metal features and parts (=solids) in one single file. That means there can be hundreds of features so there's some degree of complexity involved but nothing NX couldn't handle. Then later on I create separate part files, under the main part file, and Wave Link every single sheet metal part this way into their respective part files. I work this way so that I can ensure that for example parting lines and other visual details are perfectly aligned in the final product. And parametrically stay that way if the visual design changes somehow.

 

[pamakela]

Ok - updated to NX 9 (9.0.0.19). The original model loads into NX 9 Ok, but some of the flanges and three bend corners appear as they appeared on NX 7.5. Also now when I try to create a Three Bend Corner, I keep getting 'Flange clearance must be less than the width of the flattened central bend.' error/alert. If I reduce the clearance, I will get 'Unable to create body' error. I get the clearance nag even if I try to do a Closed corner where I can't even input any clearance value. Some three bend corners get done properly without while others don't.

I'm getting the feeling that one shouldn't use Three Bend Corner on flanges that were created by Contour Flange. Note that I must use Move Face from synchronous modeling to make Countour Flange acceptable for Three Bend Corner to begin with. Maybe this approach is not recommended?

 

[deedub777]

Since this product makes use of industrial design - area which I'm also responsible of - I want pristine sheet metal quality on the parts that are visible. Thus I'm using Closed.

What settings are you using for closed corner? Miter, Blend Miter values for example? You do know you can close the corners within the contour flange command?

It might be worth trying sb flanges with 3 bend corner and see how you get on however, one thing to note though, 3 bend corner has difficulty with 90deg flanges that's not fixed yet on NX9. Try changing the angle of the flanges from 90deg to say 89.9deg and see if that works.

Ok - updated to NX 9 (9.0.0.19).

You know that 9.0.2 is available?

Did you try using convert to sheet metal?

 

[JohnRBaker]

Actually, NX 9.0.2 is not yet available, but it's VERY close. That being said, NX 9.0.1 has been available for some time now.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[pamakela]

What settings are you using for closed corner? Miter, Blend Miter values for example? You do know you can close the corners within the contour flange command?

At the moment I can continue working by using Circular Cutout with 2.54mm diameter (sheet is 1mm thick). I can then instruct in the manufacturing drawings to fill in and polish the cutout to achieve the surface finish I'm after.

I've noticed that you can close corners in Contour flange but sometimes I just doesn't do anything. I think it won't close corners that involve a bend? But if you have a flat plate, where you don't have bends, and Contour flange it's edges, the close corner will work.

I have tried using convert to sheet metal and I think it is unnecessary in my case - it won't change anything. But in general I think that in NX 9 I've gotten rid of some issues that I think were bugs. I don't get unpredictable behavior that I got in 7.5. So things are stable now and I believe I can finish this project in time.

 

[deedub777]

Actually, NX 9.0.2 is not yet available, but it's VERY close.

Oops, my mistake