Metal plated additively manufactured plastic rotors and their method of manufacturing

A method of forming a rotor for a turbomachine, the method comprising:

• forming, by an additive manufacturing process, a plastic substrate comprising a matrix material and having an outer surface;
• embedding, by the additive manufacturing process, the matrix material of the plastic substrate with fibers having a first coefficient of thermal expansion;
• and
• applying a metal plating to at least a portion of the outer surface of the plastic substrate, the metal plating having a second coefficient of thermal expansion;
• wherein the fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating;
• wherein the plastic substrate and the metal plating together form the rotor having a hub centered on a central axis and having a disk portion and a shaft portion and a blade extending outward from the hub;
• wherein the step of embedding comprises selectively printing fibers to vary a fiber density in the plastic substrate and to form a region of increased fiber density adjacent to the portion of the outer surface of the plastic substrate to which the metal plating is applied.