Relating part expressions (within an assembly) to arrangements in NX5
Relating part expressions (within an assembly) to arrangements in NX5
(OP)
Is it possible to link changes to constants contained in a part expression to specific arrangements within an assembly?
For example, I can modify the relative position of 2 parts rotating about the same center by making the angular dimension 'arrangement specific'
So, I should be able to link a constant (loaded in the expressions) within a part to specific arrangements so if the part is flexible (like a spring) the result would be an assembly which can drive the part via the arrangements. Or should I be doing this another way??
Any advice greatly appreciated...
For example, I can modify the relative position of 2 parts rotating about the same center by making the angular dimension 'arrangement specific'
So, I should be able to link a constant (loaded in the expressions) within a part to specific arrangements so if the part is flexible (like a spring) the result would be an assembly which can drive the part via the arrangements. Or should I be doing this another way??
Any advice greatly appreciated...





RE: Relating part expressions (within an assembly) to arrangements in NX5
However, since you're using Arrangements, there is an alternative approach which might in the end prove easier to implement. You could create your spring with several different lengths in the same part file but using a different reference set for each length. Then when you create your assembly and you define your arrangements, you can suppress a component and replace it with the same part file, just using a different Reference Set, with each arrangement defined. This way as you swap arrangements the 'length' of the spring can be changed as needed. And this won't interfere with things like Parts Lists, since as far as the system is concerned, no matter which arrangement you end up using, all of the components are exactly the same since the Reference Set does not change which component the assembly thinks is loaded, just which 'version' of it is, which in the case of a spring is only to accommodate a different length.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
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To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
Regards
R.
RE: Relating part expressions (within an assembly) to arrangements in NX5
File -> Import...
...a copy of the same part file back into itself. When you do you will get a complete, fully parametric copy of your original model with a complete set of duplicate expressions and features. Just edit the second set of expressions (you will recognize them since we 'hash' them so as to reuse the original expression names) to your desired alternative values. Then just create two Reference Sets, selecting one Solid Body for each.
Note that this can be repeated as often as needed, but once you get past 3 or 4, perhaps a Deformable Component might be better.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
That said upon reading your question about the arrangements in question I might add something about interpart expressions at least in terms of developing the method a little further. Many times you will find that in an arrangement a compression spring in particular is sandwiched between two other moving parts. I varying the length of the spring all you really wish to do is measure the distance between those two and use that to drive the spring length.
You can do that with a measurement expression and then use that as the parameter that drives your deformable spring. You could also use linked interpart expressions which is I think what you were guessing at in the original post, but they are only any good to you if there is only a single instance of the spring in your assembly. Possibly the best thing with deformable parts is that if you have the same spring in two locations then you can set each to a different length.
You would also avoid multiple instances of the same component in your assembly to support your arrangements, which could just become confusing and a little bit difficult to manage.
Best Regards
Hudson
www.jamb.com.au
Nil Desperandum illegitimi non carborundum
RE: Relating part expressions (within an assembly) to arrangements in NX5
There doesn't seem to be a positive display/feedback of what is 'on' and what features are 'off'.
Also in the reference sets I have, I only seem to be able to modify one condition (the wound state) Others eg. unwound, don't seem to be selectable. How can I define reference sets for both the wound & unwound state...?
I can use the deformable state function very well within part. I set up the no. of turns expression to be the selectable variable for adjustment no problem. I apply this to the helix & the associated tube. However, if I try and modify the selectable variable within assembly (right click > deformable part) I get the box to change the variable and the spring helix changes but not the associated features. (but the whole spring updates fine in part mode...)
I tried to select all of the other features in the history but then I don't get any result either in part or assembly. I guess I'm not selecting the right features within the deformable part process. Not sure what though!! - NB my spring is a single united solid body...
I get a variety of error messages:
1. Multiple bodies exist in the definition of the deformed part. (stange as I only have on solid body??)
2. Cannot copy feature.
Seems like I'm close to getting it but not quite doing something right...
3. You have not specified all required references This can cause unexpected results or failure. (doesn't really specify in the help what I should be doing though!..)
I've attached my attempt at deforming the spring. Another thing I can't seem to do is edit the features of the user defined deform after its initial creation. Which is annoying...
RE: Relating part expressions (within an assembly) to arrangements in NX5
As for discovering the contents of a Reference Set, while in the master part, go to...
Format -> Reference Sets...
...and select the 'Model' Reference Set. If you look at the screen all the highlighted objects are already part of that Reference Set. To 'add' and 'remove' items to the Reference Set, just select the '+' or '-' buttons on the right side of the dialog and follow the steps outlined.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
1. The error message (see PDF attached)
2. The spring is added to the assembly OK. But the feature on the spring 'extrude 11' doesn't appear. (something to do with 'Missing string??)
3. If I look at the part navigator tree I see that the deforamble feature has a red cross icon on it.
4. If I double click on the spring in the assembly this Number of turns dialog appears. The deformable part works It changes the bend angle of the spring OK.
5. To move the spring right click > move doesn't appear - there is a different smaller menu with no move option... why is this?
I have to say this deformable part command has to be one of the least user friendly / intuitive I have ever seen in a CAD system.
Furthermore, from your last post, there seems to be a exclusion on using the default datum CSYS within the deform command, which is daft because the CSYS is there by default. There is no mention of its incompatability with the deform help files either.
Maybe I'm missing something here...
RE: Relating part expressions (within an assembly) to arrangements in NX5
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
Thanks for getting back, I can't seem to open that file (rev D of the spring) my NX5 won't open it. Seems that the NX you're using is newer than mine. (Though the other previous files of the spring that you sent me opened fine)
Regards
Rob.
RE: Relating part expressions (within an assembly) to arrangements in NX5
OK, try this one, which is an NX 5 part file.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
Sadly any subsequent attempts to deform are met with the same missing string error; my skills in NX5 are not good enough to work this one out.
I did have several goes at running the tools > deform command but the explanations of exactly what to include in terms of 'features' and then 'references' are thin on the ground.
What is the difference between the two?? As the reference step actually asks to 'add geometry'!? Haven't I already done that in the features step...
Appreciate your support (& patience..)
RE: Relating part expressions (within an assembly) to arrangements in NX5
As for the reference step, anything NOT included in the geometry step will show up as a needed item in the reference step. For example, let's say were modeling something like a piece of hose. You would create a spline and add a tube feature. When defining the deformable part you only include the tube feature when selecting the geometry so therefore you will need to supply the spline when adding it to the assembly.
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.
RE: Relating part expressions (within an assembly) to arrangements in NX5
There is no special fancy way of bringing in deformable parts is there? I just added component in the usual way...
My NX5 is NX 5.0.4.1. Maybe I need to be upgraded..
RE: Relating part expressions (within an assembly) to arrangements in NX5
John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Cypress, CA
http://www.siemens.com/plm
http://www.plmworld.org/museum/
To an Engineer, the glass is twice as big as it needs to be.