According to the Kinds of Operation

Flexible manufacturing system might be distinguished based upon the kinds of operation they perform:

Processing Operation:

Such operation transforms a work material from one state to another moving towards the last desired part or product. This adds value by changing the geometry, properties or appearance of the preliminary materials.

Assembly Operation:

This involves joining of two or more component to build a new entity that is called an assembly/subassembly. Permanent joining processes include, brazing, welding, soldering, adhesive bonding, press fitting, rivets and expansion fits.