Part of a factory (8,4)
I believe the answer is:
assembly line
'part of a factory' is the definition.
('assembly line' is part of 'factory')
This is all the clue.
(Other definitions for assembly line that I've seen before include "Series of machines in factory" , "Manufacturing set-up" , "Factory fabrication process" , "Eg, car plant set-up" , "Mechanical system for mass production" .)