What's the best way to use 3d printed parts for injection molding?  Need many

What’s the best way to use 3d printed parts for injection molding? Need many multiples of Jansen style linkages and molding might be faster. Any and all ideas welcome!

Keep in mind there are other types of molding too, like casting. Printing halves, and then filling with silicone (oogoo) could be one thing to play with. You’ll definitely need a release agent though, and the finer you print, the better as any crevices made by the filament will be smaller.

You can design the mold and then use a resin that cures after the mix. Thermal molding is more difficult.