This graphic is only about the tooling cost - it assumes that you already have the necessary process equipment installed and operational. So if you already own the $10,000 3-D printer, you really don't need to spend anything on tooling to print your prototype cell phone cases. But if you already own the $300,000 injection molding machine, you need to buy the mold before you can start cranking out thousands of parts per hour. But molds are going to be way more than $30,000 for steel, (try a factor of at least 3). And that assumes you get the mold designed correctly the first time. You may have to go back and remachine it, taking out a little bit more metal here and there to get the flow to fill the mold properly so that you don't end up with
- excessive shrinkage
- excessive warpage
- sink marks
- flow lines
But the graphic does get the big picture across - options exist to make "cheap plastic" products on a variety of scales. But to cheaply make something from cheap plastics requires some deep pockets. As the old joke goes, "How do you make a small fortune in the plastics industry? Start with a large fortune!"