Rather than spend time printing springs for a project, I made this little mold to make them out of raw 3mm PLA filament. It measures 3/4" by 3" tall. Since there are no shear planes in this twisted filament, the springs it creates will be a lot tougher than anything printed.
I think this concept could be used to produce torsion springs as well as conical compression springs with different molds.
If you wrapped the filament around a dowel with the sides of the filament touching, you could make an extension spring instead of a compression spring.