Mate failure in sub-assembly

Inserted some parts into a top level assembly and mated them to a
bracket. Then created a sub-assembly and moved the parts into the sub-
assembly. The bracket was left at the top level.

The bracket needed to be modified (hole spacing change), which caused
the top level mates between the bracket and the parts in the sub-
assembly to fail.

The only solutions I've found are to dissolve the sub-assembly and re-
create it, or enable the flexible sub-assembly option. Making the sub-
assembly flexible resolves the mate errors, but does not display the
parts in their correct positions when creating a detailed drawing of
the sub-assembly by itself.

Any recommendations?

 

If you need to produce a drawing of the sub-assy with all its components in
defined positions relative to one another, and these positions are identical
when the sub-assy is used in a parent assy, then you shouldn't be making it
flexible.

You only need (usually) 3 mates to fully constrain the sub-assy in the
parent assy, and this should preferably be done using its front/top/right
planes or origin. It sounds like when you initially added the components to
the top level and mated them, that you may have created more than 3 mates
between these parts and the parent assy. When you moved them down a level,
these "excess" mates caused an over-constrained situation, because the
sub-assy is treated as a single rigid body.

It may be that you got away with it at first, because there were no
conflicts and so SWX allowed the over-constrained condition, but once you
changed the geometry a conflict occurred.

It seems like you need to delete some of the constraints between the
sub-assy and the parent assy - possibly all of them and start again, if
necessary. You might also find you need to add some more constraints in the
sub-assy to fully constrain all of its components.

John H