Method of making a fuel injector nozzle

A method of fabricating a fuel injector nozzle comprising a plurality of through-holes, said method comprising the steps of:

• forming a first microstructured pattern in a polymerizable material capable of undergoing a photon reaction by selectively reacting the polymerizable material using a photon process, where the photon process enables polymerization to be confined or limited to the focal region of a focused beam of light used to expose the polymerizable material, with the first microstructured pattern comprising a plurality of microstructures, and each microstructure being a negative replica of a fuel injector nozzle through-hole and comprising a top;
• replicating at least the microstructures of the first microstructured pattern in a metal material to make a replicated structure, with the replicated structure comprising a second microstructured pattern, the second microstructure pattern comprising a negative replica of the microstructures, and the top of each microstructure being either covered with the metal material or exposed;
• for each microstructure having its top covered with the metal material, removing metal material from the replicated structure to expose the top of each microstructure covered with the metal material;
• and
• removing at least the microstructures from the replicated structure, resulting in a nozzle having a plurality of through-holes.