There would be no produced items if tool and die makers did not exist. That's because no one would be able to create the moulds that shape the plastic, or the tools that build other tools, or the dies used to stamp out parts. 

Tool and die manufacturers determine the best technique to form a piece of metal to an engineer's blueprint specifications. They use a variety of machinery to cut, bore, mill, grind, and polish the finished object with an accuracy 40 times that of a human hair. 

A single worker typically develops a single device from start to finish. This necessitates the ability to operate independently. It also necessitates a deeper understanding of mathematics and metals than most machinists have. 

It is also becoming increasingly important to be skilled with 'computer-aided design' software and the 'computer numerically controlled' devices that automate numerous procedures. But whether they're using a state-of-the-art computer or a fifty-year-old metal lathe, tool and die makers have the satisfaction of creating something that would never exist were it not for their skills. And those abilities will always be in high demand.