Formed plastic consumer goods are so incredibly common that it probably doesn't even occur to you to think about where they come from. But it seems like it should be pretty simple, right? Just melt the plastic, pour it into a mold, and let it cool.
In theory, yes. But as Bill Hammack from the University of Illinois explains below, it took a great deal of tinkering to get that simple idea to actually work reliably in practice. From getting the plastic to melt evenly to breaking the finished product out of the mold, the plastic injection molding process requires a ton of superb engineering. Check it out.
