EDM drilling of low angle holes
AssigneeUnited Technologies Corporation
InventorRobert J. Kildea
Life of this patent
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Abstract
Low angle air directing slots in the tip of an airfoil are produced by forming an elongated electrode by forming notches on opposite sides of the electrode and performing electric discharge machine with the electrode. During machining the electrode is oriented and fed at an acute angle with respect to the surface of the airfoil tip to form an opening, and then rotating the electrode to a position increasingly perpendicular to the surface of the airfoil tip.
Claims4
A method of producing low angle air directing slots in the tip of an airfoil in fluid communication with an internal pocket which is not axially aligned with the axis of said slots comprising:
- forming an elongated electrode having a penetrating inboard end, an outboard end, and two substantially parallel edges comprising an outside edge and an inside edge;
- forming a first notch in said outside edge;
- forming a second notch in said inside edge at a location on the inboard side of first notch;
- orienting said electrode at the desired low angle to the surface of the airfoil tip;
- electrically energizing said electrode for electric discharge machining;
- forming an air directing opening by axially advancing said electrode;
- and
- thereafter rotating said electrode to a position increasingly perpendicular to the surface of said tip with said first notch located at the tip surface, said second notch located at the surface of said air directing opening formed by the inside edge of said electrode, with the inboard end of said electrode penetrating into said pocket.
Dependencies are inferred from the claim text.