The type of plastic used to fabricate this pelton wheel will determine the size/scale/power of the turbine. However, the most likely approach will be to print this object in plastic (such as PLA), and create a mold, from which the wheel can be cast in stronger materials such as metal or resin. Overhangs may require support material, depending on the type of printer used. Hand finishing may be required to smooth some of the profiles, depending on the resolution of your printer.
Object can be scaled according to power requirement of pelton wheel, flow rate and pressure of water jet.
This design is based on the work by Tobias Schneider