Assembly Sequencing - violate assembly constraints? 1

[fighterpilot]

I'm creating an assembly sequence and when I go to create a motion sequence for a part that was constrained using assembly constraints, it seems I cannot violate those constraints. Parts that I have assembled w/o constraints can be moved fine.

Any ideas?

NX5.0.3.2

Thanks..

--
Fighter Pilot
Manufacturing Engineer

 

[JohnRBaker]

There is a way to override (ignore) the Constraints from within Sequencing, but it's an 'all-or-nothing' thing so you need to think about this first.

If your desire is to move a certain part, such as something which is part of a mechanism and your wish the other parts to move like they would in the physical world, and example might be something like a 4-bar link, then you can't use this override option since you actually want SOME of the Assembly Constraints to be honored, however you will need to design your assembly so that there is at least enough degrees-of-freedom (unconstrained components) so that items can actually move. In many cases, like the 4-bar link, you really should allow all of the shaft/bearing relationship to rotate freely thereby allowing linkages to move yet still drive the adjoining parts. This way when you apply a motion to the first link, say causing it to rotate about its axis, the other parts move as they are expected due the series of underconstrained relationships at each and every one of the 'joints' of the mechanism

Now if on the other hand your desire is to use Sequencing to perform a disassembly/assembly sequence then you DO NOT want the constraints to be in effect since the parts are being arbitrarily, and probably as individuals, moved. In this case after you've create a sequence, but before you add your first motion, open the 'Sequence Navigator' on the Resource Bar and expand the 'Details' panel at the bottom. Now select the item at the top showing the name of the sequence and you will notice a bunch of stuff showing up in the 'Details' panel. The last item listed should read:

Mating Constraints On

Just double click the 'On' item and it will turn to 'Off'. Now you can move the component wherever and however you wish and the Assembly Constraints will be ignored.

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

 

[fighterpilot]

John,

I'm interested in only doing assembly simulations now so the second paragraph applies to my situation. I tried your recommendations this morning and was able to move in the directions needed.

Thanks...

--
Fighter Pilot
Manufacturing Engineer