Using the SOLIDWORKS Save Bodies command without creating multiple copies
The SOLIDWORKS Save Bodies command can be used on any multibody part which allows you to create an assembly at the part level and then save it out as an assembly if that is the fastest way to model your parts. It can be very useful with Molds as they are easily modeled at the part level, but an assembly drawing may be the simplest way to annotate the resulting bodies. Multiple instances of ejector pins or identical cores can also needlessly clutter the design folder.
Source- Javelin Blog