EXPRESSIONS 2

[BGM88]

Hey,

I was wondering if its possible to use exppressions to change parts in an assymbly?

Like if i had a part family made of differt lengths of pipe and i wanted to be able to choose the nesecary part from the family to bridge a gap from A to B?

THANKS
1st year grad ME.

 

[JohnRBaker]

What version of NX are you running?

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.

 

[BGM88]

NX 7.5

 

[BGM88]

& team center if that helps

 

[JohnRBaker]

OK, extract the files in the attached zip file and open the 'Sample_Assembly.prt' and note the name of the 'Pipe_Spacer'.

Now go to...

Tools -> Expression...

...and edit the value of the 'Distance' Expression (enter any value between 10 and 200 millimeters in 10 millimeter increments, as in 10 or 20 or 30 or 40...). After the Assembly updates, go to...

Assemblies -> Components -> Part Family Update

...and note that the Assembly updates and that the Pipe_Spacer has been replaced with different Part Family member, which is the proper length to span the gap between 'A' and 'B'. If you look at the Pipe_Spacer component you will see that we've create a 'criteria' for selecting the proper Part Family member using the Distance Expression to determine which Pipe_Spacer length to key on.

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.

 

[vrishraj]

Hi John,

One question in this, I could not see how the system knows the link between the "distance" expression in the assembly part and the part family "length" to determine which Pipe_Spacer length to select. Please explain a bit and thanks in advance.

Raj
NX 7.5

 

[JohnRBaker]

The link was established when I first added the 'Pipe_Spacer-XX' component, using the Part Family dialog, to the Assembly. In the Part Family dialog there's an option to create a 'Criteria' which in this case used the value of the 'Distance' expression in the Assembly to select the appropriate Part Family Member based on matching that value to a 'Length' value found in the Family Table of the 'Pipe_Spacer.prt' master template part.

To find out if there are any 'Criteria' defined with an active Assembly, go to...

Information -> Assemblies -> Family Report

And for more information about where and how to use 'Criteria' when adding a Part Family member to your assembly, simply go to the NX Help files and search on 'Part Family Criteria'.

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.

 

[vrishraj]

Hi John,
Once again thanks for your detailed explanation, I understood the process now.
One more question, is it possible to re-edit the criteria after adding the part family member to some other existing expression in the assembly?

Raj
NX 7.5

 

[JohnRBaker]

Not that I'm aware of. What I've had to do in the past was remove the Component of interest and then reinsert it using the original master template which would once again offer me the full Part Family dialog where I could then replicate and/or add to the set of 'Criteria' controlling the selection of the Part Family member.

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.

 

[vrishraj]

Hi John,
Thanks for the information.

Raj
NX 7.5

 

[swale74]

Hi John, Any chance I could get a NX version 6.0.5.3 version of this file? Sounds interesting.

NX 6.0.5.3 in Windows 7
Mechanical designer

 

[JohnRBaker]

OK, attached is an NX 5.0 version of the files (just in case someone needs to go back even further ;-) which will behave exactly as I described in my 16 Dec 12 0:54 posting above.

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.

 

[RareEarth]

Hi John,

This is awesome!

Just one more thing, can we attach part family update command with expression updated by any mean?

Means when user will change only in expression and the Assemblies -> Components -> Part Family gets updated automatically.

 

[JohnRBaker]

I don't think this can be triggered automatically. The only way that I've ever seen it work is by using the explicit 'Part Family Update' option.

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.