creating parts that are interchangeable in manufacturing terms is key to the line

Assembly line.

Explanation:

The interchangeable parts was a game-changing concept for the manufacturing industry during the Industrial Revolution.

It was first introduced by Eli Whitney, also the inventor of the Cotton Gin, and later was perfected by Henry Ford, who was the first to create a continuous moving assembly line. The Interchangeable parts are identical pieces created from a master model and are so similar to each other, that they can fit into any line of production of the same kind.

Thanks to these advances, the manufacturing process across all industries could be now faster, more cost-efficient, and profitable.

this seems to be in the wrong category. but i'll take some free points my dude

posting this in wrong category will result in people seeing it who won't know the answer.