Some typical reasons a part cannot be successfully scaled.
#1. The part contains a rebuild error. Ctrl+Q the part with 'Verification on rebuild' enabled. If a feature failure is presented, this could well be the cause of the scale failure.
#2. The part fails a geometry check. If the part can be regenerated with 'Verification on rebuild' enabled and no failures are presented, Goto a Tools > Check dialog. This will show you any geometric faults, ( bad geometry). If this is the case, the part should investigate the features that create those bad geometries.
3. Some edges or faces of the model may become to small in a scale down. As a part's size is changed during a scale operation, the size of some geometry may fall outside of acceptable limits when a part is scaled down. Short edges can be detected using Tools > Check.
Bob McGaughey, CSWE
CATI Tech Staff