Part instance and part configuration is a functionality under configuration management which can be used to do configuration management of Serialized components and BOM.
For example:
Camera (Serialized product)
|_ BODY (Serialized part)
|_Lens (Serialized part)
|_ Sensor (NON - Serialized part)
Where you can have a Configuration of Each item i.e. Camera, BODY, LENS, SENSOR
and Each Item can have instances such as:
CAMERA - CAM-SR1000, CAM-SR1001,CAM-SR1001,
BODY - SR1000, SR1001, SR1002
LENS - 70-200mm, 18-200mm, 10-140mm
and Every instance may have End OF Life or Maintenance life in the configuration.
and once you have all information created you can allocate manage configuration/instances or BOM of a product which has assembled serialized components
hope this helps ?
Rahul