Flexible Assemblies 2

It does work better using constraints than mating conditions, and when the cylinders are defined as cylinder assemblies. John gave an excellent example a while back but I can't seem to get the search facility to work as expected. If somebody can find that thread I think it explains everything.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

I was considering making a post with a few questions regarding features/abilities and if they are possible in NX. This was one of them (does NX have a feature similar to SW's Flexible SubAssemblies).

The simplest explanation I can offer without referring to another system that I'm not familiar with is that if by flexibility you mean freedom of repositioning then everything in NX is free to move unless and until you constrain it. Once you do then constraining components to be coaxial leaves them free to slide along the axis or to rotate. As you add constraints things become more confined, but those you leave off allow most simple mechanisms to be simulated within the NX environment.

I hope that answers your question.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

Attached is an assembly ('assy_main.prt') containing two hydraulic cylinder assemblies (actually it's the same cylinder assembly simply added to the top level assembly twice). The 'cylinder' on the right has already had the position of the piston sub-assembly overridden which means that you can independently control its position by just selecting any aspect of it, such as the rod-end, and dragging it up or down using the Move Component function.

Note that the cylinder on the left has NOT been modified so if you attempt to move its piston sub-assembly you will see that it's not selectable as a movable object at this level of the assembly.

Now to show you how easy it is to override the positioning of this piston sub-assembly, for the cylinder on the left, expand that assembly in the Part Navigator so that you can see the piston sub-assembly (you do not need to expand it). Now select the 'piston_assy' component, press MB3 and select the 'Override Position' item from the list of options, which you will find in the second group of items with a Green UP Arrow as it's icon. Once the system returns control to you, you will find that you can now use the Move Component function to move the piston sub-assembly in the cylinder on the left just like you were able to do with the piston in the cylinder on the right.

Now to remove the override, just reselect the piston sub-assembly, press MB3 and select the item which is now labeled 'Remove Position Override' and you will be back to where you started.

Note that you can perform this operation at the top-level assembly without actually needing 'write' access to the cylinder or piston assembly files since all the changes are made in the top-level assembly file.

Also note that the attached cylinder assembly can be opened and manipulated as described in NX 5.0 and as well as later releases.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

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

Hudson, your description of the behavior of un- or under-constrained components is only true if all of the components are in the top-level of the current assembly. If however, we are dealing with a sub-assembly which could have it's on sub-assemblies (as is the case with my hydraulic cylinder assembly example above) then you need to use the override option to move any of these sub-components relative to the top-level assembly without moving them in their own assembly, which I think was what 'thom9446' and 'HercalloY' was looking for.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

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

John,

Thanks for posting the example I'm pretty sure it is the same one that helped me to learn about this when you posted it once before. Searching the forum for some reason is only giving me results starting at 2007. I wish I could have saved you the trouble of typing out the explanation all over again. I knew there was something more to it that I hesitated to explain because frankly although the method is really great unless you're a big user of cylinders you tend to come back to it only sporadically.

Best Regards

Hudson

www.jamb.com.au

Nil Desperandum illegitimi non carborundum

And what about flexible components (springs, hoses, etc...)?

eex23

Deformable spring attached. Add it to an assembly and use the slider to determine a length.

Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)


Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

deformable gas spring.

Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)


Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

deformable hinge. All been posted before but against other threads.

Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)


Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

John,

Thanks for your response. I was a little suprised that no one had asked this question before. I guess I'm not the only one having issues with searching the forum.

This has been asked before, but as Hudson mentioned, he was not able to find the entries from the last time this was posted.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

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

When you search the forum, try using the 'Google' search box and add the term "UG/NX" to whatever it is you are searching for. This will (mostly) limit results to the NX forum and should return all results (I just tried it out with the search term "UG/NX assembly" and got over 30 pages of results dating at least as far back as 2003).

Thanks for the samples and explanation John. That pretty much answers one of my "does NX have this feature" questions! Something tells me it'd be a hell of a lot more stable then "the other" implementation to!

to JCBCad:
heh, try to make sequence with an assembly, which has deformable spring...
o simulate the same assembly.

Not impossible,using a combination of interpart expressions, deformable parts and WAVE linking, however if you might me better using the motion scenario tool for advanced simulation l ike that. I have done some pretty neat assemblies with hoses and harnesss without using the additional routing licenses where the hose end fittings and hose material are fully associative although (as with most things) there are limitations.


Best regards

Simon NX4.0.4.2 MP10 - TCEng 9.1.3.6.c - (NX6.0.3.6 MP2 native)


Life shouldn't be measured by the number of breaths you take, but by the number of times when it's taken away...

may be you have a simple example for the spring, which deforms during assembly sequence?

What version of NX are you running?

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

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

For John R. Baker:
we working with nx4 and testing nx6.