Method of forming small-diameter channel within an object

#1. Field of the Invention

#This invention relates to a process for forming small-diameter channels in an object, and especially to a process for forming manifolds and small-diameter, surface-connected ducts in the face plate of a propellant injector for a rocket engine.

#2. Description of the Prior Art

#FIGS. 1A-D are cutaway isometric views of the different steps in the process of the present invention.

#FIG. 2 is a partial isometric view of face plate utilizing pyramidal prominences showing how the grooves may be arranged in accordance with the present invention.

#The invention will be described with relation to a plurality of sets of two ducts each, the ducts 10 being angled so that the liquids forced through the orifices 12 of any set of ducts intersect at a common point, the impingement point 14. It is to be understood that the invention encompasses the use of other numbers of ducts per set, different flange configurations and numbers, different orientation angles, and different orifice patterns. Although the invention is described specifically in relation to an injector face plate for a rocket engine, it is obvious that it may be used to fabricate other types of fluid injectors.

#If the object to be formed is a face plate of an injector, for example, a circular base plate 16 of stainless steel is commonly employed. The base plate 16 is machined to provide an annular flange 18 whose inwardly sloping sides 11 and 13 (from its base) are oriented at the angles at which the ducts are desired to be oriented. Circular grooves 20 and 22 for fuel and oxidizer manifolds are then machined into the base plate 16 at the two intersection lines of the flange 18 with the surface of the base plate 16. Grooves 10 for orifice ducts 34 to be formed later are now etched in sets of two along the sides of the flange 18 from the manifold grooves 20 and 22 to the top 24 of the flange 18. Any other suitable methods for forming the grooves 20,22 and 10 may be employed.

#The manifold grooves 20,22 and the orifice grooves 10 are filled with a subsequently removable filler material such as wax 23 (FIG. 1B). The filler material should be easily removable by melting, or dissolving, or any other suitable means. A layer 26 of a metal, such as Ni, for example, is formed by any suitable process, such as electrodeposition, over the wax-filled surface of the plate 16 (FIG. 1C). The upper surface 28 of the deposited metal layer 26 is then removed, e.g., by milling, to uncover the orifice ducts 10, the openings thereof in the machined surface 30 being known as orifices 12 (FIG. 1D). The wax 23 in the ducts 34 and manifolds 36,38 is now removed by any suitable process, such as melting by heat or dissolving by a solvent.