Additionally: If you want to _mass_ mass produce these things, an injection molding setup is going to be your goal. You can sort of hack one together for plastic molding using a pneumatic/hydraulic cylinder and some mold plates that are either cast metal (lost-PLA, lost-wax), cured plaster, or CNC'd. The stuff that will give you five million units a day costs as much as a house, but there is a middle ground that is competitive with FDM on quality but significantly faster for more like $300-$3000.

The limitation with injection molding is typically the cost and complexity of having mold plates made when you don't have a demand for all that many units.