Mates problem

I'd added a bolt, washer, spring washer, nut combination to an assembly.
The bolt was mated concentric with a hole (using cylindrical surfaces), and
the other fasteners were mated concentric to the bolt (plus some face to
face coincident mates to position them axially).

I then realised that the bolt was not concentric with the seed hole of a
feature pattern - I'd accidentally made it coincident with one of the
patterned holes.
So I edited the concentric mate to reposition the bolt.......and this gave a
load of mate errors.

SW seemed to think that the washers and nut ought still to be concentric
with the original hole, even though there was no mate giving this
relationship - if I tried moving the components, they spun on the axis of
the original hole.

I've ended up having to delete the existing concentric mates between
washers/nut and the bolt and then recreate the exact same mates in order for
it to solve.
WHY?????

Regards,
John Harland
SW2004sp5

 

Did the bolt move to the new hole. It may be possible that the direction
of the concentric made should have been flipped

 

No - when I first changed the concentric mate for the bolt to go through the
other hole, nothing moved. I had to delete this mate and recreate it, and
then the bolt moved (but nothing else).
The same thing happened with each of the other fasteners.

John Harland

 

Yeah...this type of thing reminds me of the errors I get sometimes on
coincident mates. "The surfaces are .07654 when they should be .000"

Duh! That's why I put a coincident mate there! Now do your job and
make the surfaces coincident!

Dave

 

I think then you should play some more with the values for "Alignment"
and/or "Flip" to solve it

 

Nope...this has happened with assemblies that have been around for a
while, and something else moves and the mate breaks. Sometimes a couple
of CTL-Q's will fix it, sometimes I have to suppress the mate and
manually move the part nearer to where it should be, and then unsuppress
the mate. Sometimes I need to delete the mate, and re-create it exactly
the same.

Basically, I am not getting into unsolvable mate situations, just SWX
sometimes forgets to actually perform the mate, and then complains about it.

 

Sounds like SWX has a rather fragile solver.
When the problem next happens, I'll try the suggestion of suppressing the
mate and moving the part closer to its intended position.

Regards,
John Harland