In the Component Properties dialog box, you can assign a different value for Component Reference for each instance of a component in an assembly.
For example, you can use Component Reference to store the reference designators for an electrical harness or printed circuit board assembly. When different instances of the same component have different values for Component Reference, you can show the instances as separate line items in a BOM. In drawings, you can also link the value of a component reference to the text of a balloon.
In assemblies, right-click a component, click Component Properties 
, and set a value for Component Reference. The value appears in braces { } at the end of the component name string in the FeatureManager design tree.
In SolidWorks Routing, you can assign values automatically when importing a P&ID document.
In assemblies or drawings, when inserting a column in a BOM, select COMPONENT REFERENCE for Column type.
In drawings, when inserting balloons, select
Component Reference for
Balloon text.
To link balloons to component reference values, the drawing must contain a BOM with a COMPONENT REFERENCE column.
