INTEGRATED CASTING CORE-SHELL STRUCTURE FOR MAKING CAST COMPONENT WITH NON-LINEAR HOLES
The present disclosure generally relates to integrated core-shell investment casting molds that provide filament structures corresponding to cooling hole patterns in the surface of the turbine blade or stator vane, which provide a leaching pathway for the core portion after metal casting. These filament structures may be linear or non-linear. The invention also relates to core filaments that can be used to supplement the leaching pathway, for example in a core tip portion of the mold.
1 . A method for fabricating a ceramic mold, comprising:
(a) contacting a cured portion of a workpiece with a liquid ceramic photopolymer;
(b) irradiating a portion of the liquid ceramic photopolymer adjacent to the cured portion through a window contacting the liquid ceramic photopolymer;
(c) removing the workpiece from the uncured liquid ceramic photopolymer; and
(d) repeating steps (a)-(c) until a ceramic mold is formed, the ceramic mold comprising:
(1) a core portion and a shell portion with at least one cavity between the core portion and the shell portion, the cavity adapted to define the shape of a cast component upon casting and removal of the ceramic mold, and
(2) a plurality of filaments joining the core portion and the shell portion where each filament spans between the core and shell and defines a hole in the cast component upon removal of the mold, wherein at least one filament includes at least a portion having a non-linear geometry and a cross sectional area ranging from 0.01 to 2 mm 2 .
2 . The method of claim 1 , wherein the process comprises, after step (d), a step (e) comprising pouring a liquid metal into a casting mold and solidifying the liquid metal to form the cast component.
3 . The method of claim 2 , wherein the process comprises, after step (e), a step (f) comprising removing the mold from the cast component.
4 . The method of claim 3 , wherein removing the mold from the cast component comprises a combination of mechanical force and chemical leaching.
5 . The method of claim 1 , wherein the non-linear geometry forms an “S” shaped hole upon removal of the mold.
6 . The method of claim 1 , wherein the hole exits the surface at an angle of less than 20°.
7 . The method of claim 1 , wherein the hole exits the surface at an angle in the range of 5° to 15°.
8 . A method of preparing a cast component comprising:
(a) pouring a liquid metal into a ceramic casting mold and solidifying the liquid metal to form the cast component, the ceramic casting mold comprising:
(1) a core portion and a shell portion with at least one cavity between the core portion and the shell portion, the cavity adapted to define the shape of a cast component upon casting and removal of the ceramic mold, and
(2) a plurality of filaments joining the core portion and the shell portion where each filament spans between the core and shell and defines a hole in the cast component, wherein at least one filament includes at least a portion having a non-linear geometry and a cross sectional area ranging from 0.01 to 2 mm 2 ;
(b) removing the ceramic casting mold from the cast component by leaching at least a portion of the ceramic core through the holes in the cast component.
9 . The method of claim 8 , wherein removing the ceramic casting mold from the cast component comprises a combination of mechanical force and chemical leaching.
10 . The method of claim 8 , wherein the non-linear geometry forms an “S” shaped hole upon removal of the mold.
11 . The method of claim 8 , wherein the hole exits the surface at an angle in the range of less than 20°.
12 . A ceramic casting mold comprising:
a core portion and a shell portion with at least one cavity between the core portion and the shell portion, the cavity adapted to define the shape of a cast component upon casting and removal of the ceramic mold, and
a plurality of filaments joining the core portion and the shell portion where each filament spans between the core and shell and defines a hole in the cast component, wherein at least one filament includes at least a portion having a non-linear geometry and a cross sectional area ranging from 0.01 to 2 mm 2 .
13 . The method of claim 12 , wherein the non-linear geometry forms an “S” shaped hole upon removal of the mold.
14 . The method of claim 12 , wherein the hole exits the surface at an angle of less than 20°.
15 . The method of claim 12 , wherein the hole exits the surface at an angle in the range of 5° to 15°.
16 . A single crystal metal turbine blade or stator having an inner cavity and an outer surface, a plurality of cooling holes providing fluid communication between the inner cavity and outer surface, the plurality of cooling holes having at least a portion having a non-linear geometry and a cross sectional area ranging from 0.01 to 2 mm 2 .
17 . The single crystal metal turbine blade or stator of claim 16 , wherein the non-linear geometry forms an “S” shaped hole upon removal of the mold.
18 . The single crystal metal turbine blade or stator of claim 16 , wherein the hole exits the surface at an angle of less than 20°.
19 . The single crystal metal turbine blade or stator of claim 16 , wherein the hole exits the surface at an angle in the range of 5° to 15°.
20 . The single crystal metal turbine blade or stator of claim 16 , where the single crystal metal is a superalloy.