Well I think replicator is a total misnomer. I am pretty sure that in this case the engineer involved drew up a 3D rendering of the part he wanted including any microstructure (he could have made it hollow if he wanted).
I mean it's not like this thing scanned in the broken pulley and made a replica based on the scan.
Now I know they can do this (someone mentioned a Godzirra) and I saw on Beyond 2000 (10 years ago) how this thing was used in surgery. A guy had his skull smashed to bits in an accident. They did an MRI and built a model of his skull including the broken bits. This enabled the surgeons to examine the fragments and figure the best way to put them back together (of course this was before they operated).
I thought that was a way cooler implementation and closer to a true replicator.