In a manufacturing facility, the only people who work off of blueprints are the manufacturing process engineer and the QC engineer.Nobody can build a rifle w/o following the blueprints. One might be lucky once but that's it.
We are not talking minor tolerances of 1 or 2 thousands nor precision type of rifle process but some basic things that, if not followed, lead to major problems that deliver unacceptable results.
The people on the floor doing the actual machining use process instructions given to them by engineers, not the blueprint. They only need to know about the features they're creating at their station and how to verify that their work meets the process instructions.
The process engineer's job is to provide the tools and processes to make product that meets blueprint specifications.
The QC engineer's job is to make sure the process engineer did his.
No out-of-spec stuff should ever get out the door.