A method for producing a component of a separation element for separating aaseous or vaporous mixture into fractions, which element is composed of a plurality of separating nozzle structures presenting passages defining mixture supply channels, separating chambers and fraction discharge channels, which method includes: forming a negative mold of the component by: providing a plate of a selected material whose ability to be removed from the plate is influenced by application of selected radiation; irradiating portions of the plate with such radiation in a pattern corresponding to the passages presented by the nozzle structure and to an extent such that material outside of the regions delimiting the passages is removable more easily than material within those regions; and removing the more easily removable material from the plate to create the negative mold of the component and forming the component by: filling the openings in the negative mold with a second material to create a solid plate-shaped member; and removing the negative mold from the plate-shaped member.