Object with a small orifice and method of making the same

摘要

An object with a small orifice has a highly precise orifice diameter which is produced prior to the firing of the object. A ferrule having an orifice is placed inside of a bore in a casing, preferably a ceramic casing. The casing is then shrunk around the ferrule, preferably by sintering, with the cross-sectional areas of both the ferrule and its orifice remaining constant during the shrinking step. Consequently, the ferrule is securely fixed within the casing without any gaps between the two. In an alternative method, the ferrule is pre-shrunk and placed inside the bore, where it expands to fill the bore.