What are the limitations of constraints in inventor?

[aardvarkdw]

I was wondering if anyone knows if you can use constraints to limit the range of motion for a part? I want to be able to stop a part from moving past a certain point in an assembly but I still want it to be able to move. I am having trouble with things blowing up when I move them too far and was hoping I could prevent that.

 

[DesignerMike]

I think that using constraints for this function is difficult (I have never had much luck). I have had very limited results using forumulas in the parameter screen (if I remember right).
It is much easier to use contact solver on a few components that will hold everything together (like a cylinder or latch for example).

right click on the chosen parts, and "add to contact set", then before you drag anything (or drive a constraint), under "tools" "activate contact solver. With a cylinder you will need some clearance between the parts. It should stop motion at the end of the stroke.

 

[aardvarkdw]

Thanks, that's about what I had figured was the case. I didn't think that there was much else I could do with constraints.
I had never used contact solver or the drive constraint function before though, didn't know how they worked. They are pretty easy to figure out.

I found using the contact solver that it seemed to stop the movement well before contact, I may be wrong, or my parts may contact in a place I'm not seeing. I'll play around with it and see what I come up with.

Thanks for the help

 

[DesignerMike]

I haven't used contact solver that much, but every time I have it has been correct with interference. It would be nice if it highlighted the "contact spot", but that would be too cool!

Another option is using "animator" from Sean and Charles.

http://www.mcadforums.com/forums/viewtopic.php?t=1475

Or check out this neat add-in from Matt H

http://www.mcadforums.com/forums/viewtopic.php?t=3295

If you are running R10, you will have a bunch of other "animation" options built into Inventor Studio.

Contact solver works pretty well with driving constraints, and you can really start to see the actual movements.

 

[aardvarkdw]

I think I figured out what is wrong. I started at this company about 6 months ago and therefore I didn't do the original model for some of these parts. One of the parts is about 10 thousandths too big in one of the features which is enough that it isn't a problem for manufacturing but inventor has issues with it. The two parts touch just enough to cause a collision and stop the motion before it reaches where it should be.

Thank you for the advice and the links, now I need to see if I can fix the model without causing any other problems.

 

[DesignerMike]

If at all possible try to just edit dimensions and avoid deleting features. Nothing worse than a complicated assembly that blows apart when it looses a couple constraints!