Trouble with Adjustable Assy V19

[KENAT]

Having trouble and wonder if anyone can suggest anything.

I have some bearing slides, the assy of which are set up so that travel along them in unconstrained.

At the next level - X-Y drive - I have 2 of these slides set as adjustable assemblies and all is good. At this level I've again left them free to travel by suppressing the relationship in the relevant direction.

Next level assy, I can't get them to adjust. I make the X-Y drive assy adjustable in the feature tree. Put a constraint in to control their travel but it defaults to a floating relationship. If I switch it to one I can put a dimension in, I can enter a new dimension, the new dimension shows, but the parts don't move.

I tried importing just the X-Y drive to a new assy (in case I'd got conflicting assy constraints somewhere) and couldn't get it to work. The parts attached to the XY drive that should be showing 'unconstrained' when I make it adjustable mostly don't - while a couple it shouldn't effect have the red lightning bolt showing they failed.

The X-Y drive is the first part in the assy so is grounded.

The relationship I'm trying to put in is between components of the XY drive (between limit switch and stop) - is this the issue? Does the relationship need to be to something not in the adjustable assy?

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[beachcomber]

Hi Kenat,

"At the next level - X-Y drive" is where the adjustment has to be defined.
I don't think you can define the adjusment from the NEXT level up.
In other words adjustment has to be defined in the assembly in which the adjustables are inserted.

bc.
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[KENAT]

Beach, sorry, not sure what you're saying. I've set the slides to be adjustable in the next level assy - the X-Y Drive. It's the next level after that I'm having issues. I did finally get them moving on Friday but not as intended.

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[KENAT]

Ah, I think maybe I've worked out what you were saying.

Were you trying to tell me I need to define the slides as adjustable at the next level up, as well as setting the overall X-Y drive as adjustable?

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[beachcomber]

I'll try and clarify:

Say assembly 'A' is the one that has to be adjusted.
This is inserted into another assembly 'B' as an adjustable assembly.
Its in 'B' that the constraints to adjust 'A' have to be defined.
Now insert 'B' into assembly 'C' and in the assembly tree 'A' has to be flagged as adjustable.
I think 'B' might have be flagged as adjustable also.
I don't think you can put constraints in 'C' to position the adjustable parts in 'A'.

bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.

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[KENAT]

Well, the bit about having to make assy 'A' adjustable in assy 'C' is correct.

However, it appears that assy 'A' has to be left with the direction of travel unconstrained in assy 'B' and that the constraint does have to be placed in assy 'C'.

That or something screwy is going on. I appear to have it working.

Thanks for the help.

Ken

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[HDS]

Be careful about what gets attached to your adjustable assembly in C. If there is a pattern in the assembly on the parts that get moved the pattern may not move.

 

[KENAT]

I remembered that yesterday and spent a bunch of time dropping patterns, thanks.

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[beachcomber]

Its a difficult to explain how adjustable assemblies work, but basically you are moving the positioning constraints UP one level in the assembly tree.

bc.
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[KENAT]

Yeah, part of the issue was that although I'd set the slides adjustable at the next assy level I hadn't set the drive screw assy's adjustable so that's why some of the stuff wouldn't' move or moved strangely. It's all working now but it is a bit of a pain having to leave the direction of travel unconstrained at a bunch of levels till I get to my top level system assy - especially as it's the next level down that will probably be shared by other projects.

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[beachcomber]

I've said before that once a sub-assembly is defined as adjustable in a parent assembly that should be end of story.
No way should you have to keep wading through the assembly tree at higher levels and once again define it as adjustable.
As for leaving the parts under-constrained I don't really see an alternative, unless you had a special setting for a constraint that has a nominal value, but can be adjusted.
A sort of fixed but floating setting. I'm sure that must be possible - if the developers had time to do really useful stuff instead of redesigning the interface and fixing stuff that wasn't broken in previous releases!
I have created configurations before for an assembly of a hydraulic cylinder. I had one config at max, one at min and one under-constrained to allow it to be adjustable.
I even had an adjustable part for the rubber bellows.
The number of corrugations stayed the same when the bellows was extended. Looked really good in the drawings, but a PITA to do.

bc.
2.4GHz Core2 Quad, 4GB RAM,
Quadro FX4600.

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[KENAT]

Yeah, they tend to be a pain, I just hadn't done one for a while and I'm not sure anyone here has done one quite this complex/as many layers.

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