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Assembly Constraints Solver

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stephlouv

Mechanical
Sep 10, 2013
125
Hi all,

I have a large assembly, 494 objects, 500 assembly constraints (AC), but a lot are pattern.
I am grouping the AC according to status.
Error (0)
Warning (0)
Info (0)
OK (500)

In this assembly, I have a flange cover (pastel orange), place with two constraints (orange):
- concentric
- align to stop the rotation.
(hole in the cover aligned with bolt placed on a bolt circle diameter)

On this cover, I am now editing the position of this hole.
The two BCD won't match and I should have the align in error.

But then, I get 18 errors !
Like if the constraints solver looking for a solution to this and listing all the constraint that could fix it.

I am the creator of this assembly, I know how it's made.
But now, if someone have to work with and have this to sort out.
He can spend a half day trying to fix all constraints ... but fixing a single one would have solved all !

It there a settings for this ?
Is there a way to show the root source of those errors ?
Is this a normal NX behavior ?

Thank you for reading.

Stéphane

"My english is bad ? That's why i'am french."
 
 http://files.engineering.com/getfile.aspx?folder=f523b7e4-93be-42b4-b4f0-097221a6bd6c&file=ac_errors.jpg
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BTW, this assembly is under TeamCenter and it takes now ages to modify a component when the all assembly is loaded.
Editing a basic chamfer can take 90s of "Updating objects ..."
Really not productive.
Tips & tricks are welcome.

"My english is bad ? That's why i'am french."
 
To start with, what version of NX are you using?

As for the update issue, try going to...

Menu -> Tools -> Update -> Interpart Update

...and toggle ON both the 'Delay Assembly Constraints Update' and 'Delay Geometry, Expressions and PMI Update'. If you leave these toggled ON then you can control when updates are performed by simply going back to the same location and selecting the 'Update All' item. This will force an update but it will leave the Update option toggles ON so that you can continue to work without any updates until you're ready for another general update, which you have complete control over.

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

To an Engineer, the glass is twice as big as it needs to be.
 
Under NX 9.0.1.3 and TeamCenter 9

"My english is bad ? That's why i'am french."
 
Is there somewhere a "dependencies graph" of the assembly constraints ?

"My english is bad ? That's why i'am french."
 
I'm not sure a dependency graph would show you a lot since there is no true hierarchy. Assembly Constraints are not a normal parent-child relationship but rather peer-to-peer.

Now if you open the Constraint Navigator and list the constraints using the 'Group by Constraint' option and expanding the constraint nodes will show you the Components that they apply to.

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

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