Well as you can see in the title, this is how to do plastic injection molding. It's like magic! Let’s get more of an idea of how such a thing works, and why it is so good at what it does.
We think the way things are made with plastic injection molding is really cool. It begins as tiny plastic pellets that are melted into liquid. Then the liquid is forced into a mold, in a manner analogous to filling an ice cube tray with water. Once the plastic is cool and hard, you remove the part, and there you have it! So there you have it - you have a nice all-new plastic thing.