DIE CAST SYSTEM FOR FORMING A COMPONENT USABLE IN A GAS TURBINE ENGINE

Abstract

A die cast system having an inner liner insert that enables the configuration of a component produced by the system to be easily changed by changing the inner liner insert without having to rework the die housing is disclosed. Because the inner liner insert only need be removed and replaced to change the configuration of an outer surface of a component produced by the system, the cost savings is significant in contrast with conventional systems in which the die would have to be reworked.

Description

FIELD OF THE INVENTION

This invention is directed generally to die cast systems, and more particularly to manufacturing methods for turbine airfoils usable in turbine engines.

BACKGROUND

Turbine blade airfoils typically have internal cooling systems formed from a plurality of cooling channels, as shown in FIGS. 2 and 3. To form these cooling channels inside of a blade, a casting mold is often used and includes an internal ceramic core and external ceramic shell. The ceramic core, as shown in FIG. 1, is manufactured to include detail features on the core die surface in order to form efficient cooling devices inside the blade casting. The core dies typically used to form cores are most often formed from hard steel, which are expensive to manufacture. The core die surfaces are typically in direct contact with the ceramic core material during the high pressure injection process. The core die will wear out after sufficient injections and lead to non-conforming casting. To maintain accurate casting dimensions, the core die needs to be reworked or replaced when a core die becomes worn, which is an expensive endeavor. Even a small improvement on an internal surface requires that a completely new die be made. Thus, a need exists for a more robust, less expensive system.

SUMMARY OF THE INVENTION

A die cast system having an inner liner insert that enables the configuration of a component produced by the system to be easily changed by changing the inner liner insert without having to rework the die housing is disclosed. Because the inner liner insert only need be removed and replaced to change the configuration of an outer surface of a component produced by the system, the cost savings is significant in contrast with conventional systems in which the die would have to be reworked. The die cast system may also include an inner liner formed from first and second end sub-inner liners, whereby the first end sub-inner liner may be from a first material that is less compliant than a material forming the second end sub-inner liner enabling more intricate cooling systems to be created by the second end sub-inner liner that is formed from a more compliant material.

In at least one embodiment, the die cast system may include a die housing having one or more inner chambers forming an insert receiving chamber and one or more inner liners positioned within the insert receiving chamber of the inner chamber of the die housing. The inner liner may have an inner surface defining boundaries useful to form an inner surface of a turbine component, whereby the inner liner may be formed via a selective laser melting process. The inner liner may be formed from a first side sub-inner liner forming a first side of the turbine component and a second side sub-inner liner forming a second side of the turbine component. The first side sub-inner liner may form an outer wall of a suction side of an airfoil usable in a gas turbine engine and may include at least one cavity on an inner side of the outer wall that is configured to form at least a portion of an internal airfoil cooling system. The second side sub-inner liner may form an outer wall of a pressure side of an airfoil usable in a gas turbine engine and may include one or more cavities on an inner side of the outer wall that is configured to form at least a portion of an internal airfoil cooling system.

In at least one embodiment, the inner liner may be formed from a non-ceramic, flexible material. The inner liner may be formed from a different material than the die housing. The die housing may be formed from a first sub-die housing and a second sub-die housing having a mateable interface positioned therebetween such that the first and second sub-die housings are mateable at the mateable interface.

In another embodiment, the inner liner may be formed from a first end sub-inner liner forming a first end of the turbine component and a second end sub-inner liner forming a second end of the turbine component. The first end sub-inner liner may be formed from a first material that is less compliant than a material forming the second end sub-inner liner. The second end sub-inner liner being more compliant may be used to form intricate aspects to the internal cooling system. The first end sub-inner liner may be configured to form a leading edge of an airfoil usable in a turbine engine and second end sub-inner liner is configured to form a trailing edge of the airfoil usable in the turbine engine.

In at least one embodiment, the first end sub-inner liner may be formed from a first end, first side sub-inner liner and a first end, second side sub-inner liner. The first end, first side sub-inner liner may form a suction side outer wall of an upstream portion of a suction side of an airfoil usable in a gas turbine engine and may include one or more cavities on an inner side of the suction side outer wall that is configured to form at least a portion of an internal airfoil cooling system. The first end, second side sub-inner liner may form a pressure side outer wall of a pressure side of the upstream portion of an airfoil usable in a gas turbine engine and may include one or more cavities on an inner side of the pressure side outer wall that is configured to form at least a portion of an internal airfoil cooling system.

The second end sub-inner liner may be formed from a second end, first side sub-inner liner and a second end, second side sub-inner liner. The second end, first side sub-inner liner may form a suction side outer wall of a downstream portion of a suction side of an airfoil usable in a gas turbine engine and may include one or more cavities on an inner side of the suction side outer wall that is configured to form at least a portion of an internal airfoil cooling system. The second end, second side sub-inner liner may form a pressure side outer wall of a pressure side of the downstream portion of an airfoil usable in a gas turbine engine and may include one or more cavities on an inner side of the pressure side outer wall that is configured to form at least a portion of an internal airfoil cooling system.

A method of forming a turbine component is disclosed. The method may include injecting a ceramic material into at least one inner cavity formed within a composite die cast system, wherein the die cast system may be formed from a die housing having one or more inner chambers forming an insert receiving chamber and one or more inner liners positioned within the insert receiving chamber of the inner chamber of the die housing. The inner liner may have an inner surface defining boundaries useful to form an inner surface of a turbine component. The inner liner may be formed via a selective laser melting process. The method may also include removing the die cast system thereby revealing a ceramic core.

The method may include firing the ceramic core, placing the ceramic core within an inner cavity formed by an inner surface of a wax die, and injecting wax into one or more openings formed between the ceramic core and the inner surface of the wax die. The method may also include removing the wax die to reveal a wax component, coating the wax component with a ceramic coating to form a ceramic shell with a ceramic core positioned therein and removing the wax component within the ceramic coating leaving one or more cavities within the ceramic coating. The method may also include filling the cavity within the ceramic coating with a molten metal and removing the ceramic shell and the ceramic core to form a cast component.

An advantage of the composite die cast system is that because the inner liner insert only need be removed and replaced to change the configuration of an inner surface of a component produced by the system, a significant cost savings is captured in contrast with conventional systems in which the die would have to be reworked.

Another advantage of the hybrid die cast system is that use of the hybrid die cast system will reduce time and effort required to create a core die in a conventional casting process.

Yet another advantage of the hybrid die cast system is that the inner liner may be formed from different portions formed from different materials, thereby enabling portions of the inner liner proximate to aspects of the core where intricate aspects of an internal cooling system are located, to be formed from more compliant material enabling those intricate aspects of the internal cooling system to be formed.

These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.

FIG. 1 is a perspective view of a conventionally formed core.

FIG. 2 is a cross-sectional view of two adjacent conventional turbine airfoils.

FIG. 3 is a cross-sectional view of a conventional turbine airfoil with an internal cooling system.

FIG. 4 is a cross-sectional view of an inner liner of the die cast system.

FIG. 5 is a cross-sectional view of an inner liner positioned within a die housing of the die cast system.

FIG. 6 is a cross-sectional view of a ceramic material injected within the inner liner positioned within a die housing of the die cast system.

FIG. 7 is a cross-sectional view of a ceramic core.

FIG. 8 is a cross-sectional view of a ceramic core after firing.

FIG. 9 is a cross-sectional view of a ceramic core after firing placed in a wax die and wax injected into the openings between the ceramic core and the wax die.

FIG. 10 is a cross-sectional view of a wax pattern with the ceramic core and with the wax die removed.

FIG. 11 is a cross-sectional view of the wax pattern with a ceramic shell formed around the wax pattern.

FIG. 12 is a cross-sectional view of the ceramic shell and ceramic core with the wax pattern removed.

FIG. 13 is a cross-sectional view of the ceramic shell and ceramic core with molten metal in the ceramic casting mold.

FIG. 14 is a casting of a component with the ceramic shell and ceramic core removed.

FIG. 15 is a flow chart of a method of forming a casting component, such as, but not limited to, an airfoil from cast metal.

FIG. 16 is a cross-sectional view of an alternative inner liner of the die cast system.

FIG. 17 is a cross-sectional view of the alternative inner liner of FIG. 16 positioned within a die housing of the die cast system.

FIG. 18 is a cross-sectional view of a ceramic material injected within the alternative inner liner of FIG. 16 positioned within a die housing of the die cast system.

FIG. 19 is a cross-sectional view of a ceramic core.

FIG. 20 is a cross-sectional view of a ceramic core after firing.

FIG. 21 is a cross-sectional view of a ceramic core after firing placed in a wax die and wax injected into the openings between the ceramic core and the wax die.

FIG. 22 is a cross-sectional view of a wax pattern with the ceramic core and with the wax die removed.

FIG. 23 is a cross-sectional view of the wax pattern with a ceramic shell formed around the wax pattern.

FIG. 24 is a cross-sectional view of the ceramic shell and ceramic core with the wax pattern removed.

FIG. 25 is a cross-sectional view of the ceramic shell and ceramic core with molten metal in the ceramic casting mold.

FIG. 26 is a casting of a component with the ceramic shell and ceramic core removed.

FIG. 27 is a perspective view of a turbine airfoil formed with the die cast system of FIGS. 4-14 and 16-26 and via the method of using the system shown in FIG. 15.

FIG. 28 is a cross-sectional view of the turbine airfoil taken along section line 28-28 in FIG. 27.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 4-28, a die cast system 10 having an inner liner insert 12 that enables the configuration of a component 14 produced by the system 10 to be easily changed by changing the inner liner insert 12 without having to rework the die housing 16 is disclosed. Because the inner liner insert 12 only need be removed and replaced to change the configuration of an inner surface 18 of a component 14 produced by the system 10, the cost savings is significant in contrast with conventional systems in which the die would have to be reworked. The die cast system 10 may also include an inner liner 12 formed from first and second end sub-inner liners 20, 22, whereby the first end sub-inner liner 20 may be from a first material that is less compliant than a material forming the second end sub-inner liner 22 enabling more intricate cooling systems to be created by the second end sub-inner liner 22, which is more compliant than the first end inner liner 20.

In at least one embodiment, the die cast system 10 may include a die housing 16 may have one or more inner chambers 23 forming an insert receiving chamber 24. The die cast system 10 may also include one or more inner liners 12 positioned within the insert receiving chamber 24 of the inner chamber 24 of the die housing 16. The inner liner 12 may have an inner surface 26 defining boundaries useful to form an inner surface 18 of a turbine component 14. In at least one embodiment, the inner surface 26 of the inner liner 12 may be configured to form an airfoil 138 usable in a gas turbine engine. The airfoil 138 may be formed from a generally elongated, hollow airfoil 140 having a leading edge 142 on an opposite side from a trailing edge 144 and separated by a concave pressure side 146 and a convex suction side 148. The generally elongated, hollow airfoil 60 may have one or more film cooling holes 150 at one or more of the leading edge 142 forming a showerhead, concave pressure side 146, the convex suction side 148 or the trailing edge 144, or any combination thereof.

In at least one embodiment, the inner liner 12 may be formed via a selective laser melting process, with a material such as, but not limited to, iron. The inner liner 12 may be formed from a first side sub-inner liner 30 forming a first side 32 of the turbine component 14 and a second side sub-inner liner 34 forming a second side 36 of the turbine component 14. In at least one embodiment, as shown in FIG. 4-6, the first side sub-inner liner 30 may be formed from an outer wall 38 of a suction side 40 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 46 of the outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The second side sub-inner liner 34 may form an outer wall 50 of a pressure side 52 of the airfoil shaped core 42 and may include one or more cavities 44 on an inner side 56 of the outer wall 50 that is configured to form at least a portion of an internal airfoil cooling system 48. In at least one embodiment, as shown in FIGS. 4-6, the first side sub-inner liner 30 and the second side sub-inner liner 34 may together form a plurality of inner cavities 44 forming the internal airfoil cooling system 48.

In at least one embodiment, the inner liner 12 may be formed from a non-ceramic material, such as, but not limited to, iron, or another appropriate material. The inner liner 12 may be formed from a different material than the die housing 16. The die housing 16 may be formed from a first sub-die housing 58 and a second sub-die housing 60 having a mateable interface 62 positioned therebetween such that the first and second sub-die housings 58, 60 are mateable at the mateable interface 62.

In at least one embodiment, as shown in FIGS. 16-18, the inner liner 12 may be formed from a first end sub-inner liner 20 forming a first end 64 of the turbine component 14 and a second end sub-inner liner 22 forming a second end 66 of the turbine component 14. The first end sub-inner liner 20 may be formed from a first material that is less compliant than a material forming the second end sub-inner liner 22. As such, that less compliant material may be used to form intricate aspects of the internal cooling system 48. In at least one embodiment, the second end sub-inner liner 22 form from the less compliant material may be formed by processes employed by Mikro Systems of Charlottesville, VA. The first end sub-inner liner 20 may be configured to form a leading edge 70 of an airfoil shaped core 42 usable in a turbine engine, and second end sub-inner liner 22 may be configured to form a trailing edge 72 of the airfoil shaped core 42 usable in the turbine engine.

In at least one embodiment, as shown in FIGS. 16-18, the first end sub-inner liner 20 may be formed from a first end, first side sub-inner liner 74 and a first end, second side sub-inner liner 76. The first end, first side sub-inner liner 74 may form a suction side outer wall 38 of an upstream portion 78 of a suction side 40 of an airfoil shaped core 42. The first end, first side sub-inner liner 74 may include one or more cavities 44 on an inner side 46 of the suction side outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The first end, second side sub-inner liner 76 may form a pressure side outer wall 50 of a pressure side 52 of the upstream portion 78 of an airfoil shaped core 42. The first end, second side sub-inner liner 76 may include one or more cavities 44 on an inner side 56 of the pressure side outer wall 50 that is configured to form at least a portion of the internal airfoil cooling system 48.

Similarly, the second end sub-inner liner 22 may be formed from a second end, first side sub-inner liner 80 and a second end, second side sub-inner liner 82. The second end, first side sub-inner liner 80 may form a suction side outer wall 38 of a downstream portion 84 of a suction side 40 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 46 of the suction side outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The second end, second side sub-inner liner 82 may form a pressure side outer wall 50 of a pressure side 52 of the downstream portion 84 of the airfoil shaped core 42 and may include one or more cavities 44 on an inner side 56 of the pressure side outer wall 50 that is configured to form at least a portion of the internal airfoil cooling system 48.

As shown in FIG. 15, a method 100 of forming a turbine component 14 may include forming a ceramic core die 90 at 101 and FIGS. 4 and 16 via a selective laser melting process. The die 90 may be positioned within a die housing 16 at 102 and FIGS. 5 and 17. The method 100 may also include injecting a ceramic material 98 at 103 and FIGS. 6 and 18 into one or more inner cavities 44 formed within a die cast system 10 in which the die cast system 10 may be formed from a die housing 16 having one or more inner chambers 23 forming an insert receiving chamber 24. The die cast system 10 may also include one or more inner liners 12 positioned within the insert receiving chamber 24 of the inner chamber 23 of the die housing 16. The inner liner 12 may have an inner surface 26 defining boundaries useful to form an inner surface 18 of a turbine component 14. The inner liner 12 may be formed via a selective laser melting process. The method may include removing the die cast system 10 at 104 and FIGS. 7 and 19 thereby revealing a ceramic core 90.

The method may also include firing the ceramic core 90 at 106 and FIGS. 8 and 20 and placing the ceramic core 90 at 108 within an inner cavity 92 formed by an inner surface 94 of a wax die 96. The method may also include injecting wax 88 at 110 and FIGS. 9 and 21 into at least opening 92 formed between the ceramic core 90 and the inner surface 94 of the wax die 96. The method may include removing the wax die 96 at 112 and FIGS. 10 and 22 to reveal a wax component 86 and coating the wax component 86 at 114 and FIGS. 11 and 23 with a ceramic coating 116 to form a ceramic shell 118 with a ceramic core 90 positioned therein. The method may include removing the wax component 86 at 120 and FIGS. 12 and 24 within the ceramic coating 116 leaving one or more cavities 122 within the ceramic coating 116. The method may include filling the cavity 122 at 124 and FIGS. 13 and 25 within the ceramic coating 116 with a molten metal and removing the ceramic shell 118 and the ceramic core 90 at 126 and FIGS. 14 and 26 to form a cast component 14.

The step of injection a ceramic material at 102 may include injecting a ceramic material into at least one inner cavity 122 formed within the composite die cast system 10, wherein the inner liner 12 is formed from a first side sub-inner liner 30 forming a first side 32 of the turbine component 14 and a second side sub-inner liner 34 forming a second side 36 of the turbine component 14. The step of injection a ceramic material at 102 may include injecting a ceramic material into at least one inner cavity 122 formed within the composite die cast system 10, wherein the first side sub-inner liner 30 may form an outer wall 38 of a suction side 40 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 46 of the outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The second side sub-inner liner 34 may form an outer wall 50 of a pressure side 52 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 56 of the outer wall 50 that is configured to form at least a portion of an internal airfoil cooling system 48.

The step of injection a ceramic material at 102 may include injecting a ceramic material into at least one inner cavity 122 formed within the composite die cast system 10, wherein the inner liner 12 may be formed from a first end sub-inner liner 20 forming a first end 64 of the turbine component 14 and a second end sub-inner liner 22 forming a second end 66 of the turbine component 14, wherein the first end sub-inner liner 20 may be formed from a first material having a less compliant than a material forming the second end sub-inner liner 22.

The step of injection a ceramic material at 102 may include injecting a ceramic material into at least one inner cavity 122 formed within the composite die cast system 10, wherein the first end sub-inner liner 20 may be formed from a first end, first side sub-inner liner 74 and a first end, second side sub-inner liner 76, and wherein the first end, first side sub-inner liner 74 may form a suction side outer wall 38 of an upstream portion 78 of a suction side 40 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 46 of the suction side outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The first end, second side sub-inner liner 76 may form a pressure side outer wall 50 of a pressure side 52 of the upstream portion 78 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 56 of the pressure side outer wall 50 that is configured to form at least a portion of an internal airfoil cooling system 48.

The step of injection a ceramic material at 102 may include injecting a ceramic material into at least one inner cavity 122 formed within the composite die cast system 10, wherein the second end sub-inner liner 22 may be formed from a second end, first side sub-inner liner 80 and a second end, second side sub-inner liner 82, and wherein the second end, first side sub-inner liner 80 may form a suction side outer wall 38 of a downstream portion 84 of a suction side 40 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 46 of the suction side outer wall 38 that is configured to form at least a portion of an internal airfoil cooling system 48. The second end, second side sub-inner liner 82 may form a pressure side outer wall 50 of a pressure side 52 of the downstream portion 84 of an airfoil shaped core 42 and may include one or more cavities 44 on an inner side 56 of the pressure side outer wall 50 that is configured to form at least a portion of an internal airfoil cooling system 48.

The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.

Claims

1-13. (canceled)

14. A core die cast system comprising:

a die housing having an insert receiving chamber; at least one inner liner formed via selective laser melting and positioned within the insert receiving chamber of the die housing, wherein the at least one inner liner has an inner surface corresponding to an inner surface of a turbine component.

15. The core die cast system of claim 14, characterized in that the at least one inner liner comprises a first side sub-inner liner having a body shape corresponding to a first side of the turbine component and a second side sub-inner liner having a body shape corresponding to a second side of the turbine component.

16. The core die cast system of claim 15, characterized in that the first side sub-inner liner comprises a body shape corresponding to an outer wall of a suction side of an airfoil in a gas turbine engine, and wherein the second side sub-inner liner comprises a body shape corresponding to an outer wall of a pressure side of an airfoil in a gas turbine engine.

17. The core die cast system of claim 14, characterized in that the at least one inner liner comprises a non-ceramic material.

18. The core die cast system of claim 14, characterized in that the at least one inner liner comprises a different material than the die housing.

19. The core die cast system of claim 14, characterized in that the die housing comprises a first sub-die housing and a second sub-die housing having a mateable interface positioned therebetween such that the first and second sub-die housings are mateable at the mateable interface.

20. The core die cast system of claim 14, characterized in that the inner liner comprises a first end sub-inner liner having a body shape corresponding to a first end of the turbine component and a second end sub-inner liner having a body shape corresponding to a second end of the turbine component.

21. The core die cast system of claim 20, characterized in that the first end sub-inner liner comprises a first material less compliant than a material of the second end sub-inner liner.

22. The core die cast system of claim 20, characterized in that the first end sub-inner liner comprises a body shape corresponding to a leading edge of an airfoil in a turbine engine and second end sub-inner liner comprises a body shape corresponding to a trailing edge of the airfoil in the turbine engine.

23. The core die cast system of claim 20, characterized in that the first end sub-inner liner comprises a first end, first side sub-inner liner and a first end, second side sub-inner liner.

24. The core die cast system of claim 23, characterized in that the first end, first side sub-inner liner comprises a body shape corresponding to a suction side outer wall of an upstream portion of a suction side of an airfoil in a gas turbine engine and includes at least one cavity defined by the first end, first side sub-inner liner, and wherein the first end, second side sub-inner liner comprises a body shape corresponding to a pressure side outer wall of a pressure side of an upstream portion of an airfoil in a gas turbine engine and includes at least one cavity defined by the first end, second side sub-inner liner.

25. The core die cast system of claim 20, characterized in that the second end sub-inner liner comprises a second end, first side sub-inner liner and a second end, second side sub-inner liner.

26. The core die cast system of claim 25, characterized in that the second end, first side sub-inner liner comprises a body shape corresponding to a suction side outer wall of a downstream portion of a suction side of an airfoil usable in a gas turbine engine and includes at least one cavity defined by the second end, first side sub-inner liner, and wherein the second end, second side sub-inner liner comprises a body shape corresponding to a pressure side outer wall of a pressure side of the downstream portion of an airfoil in a gas turbine engine and includes at least one cavity defined by the the second end, second side sub-inner liner.

27. A method of forming a turbine component comprising:

injecting a ceramic material into at least one inner cavity formed within a core die cast system, wherein the core die cast system comprises: a die housing having an insert receiving chamber; at least one inner liner formed via selective laser melting and positioned within the insert receiving chamber of the die housing, wherein the at least one inner liner has an inner surface corresponding to an inner surface of the turbine component;

removing the die cast system to reveal one or more ceramic cores;

firing the one or more ceramic cores;

placing the one or more ceramic cores within an inner cavity formed by an inner surface of a wax die; and

injecting wax into one or more openings formed between the one or more ceramic cores and the inner surface of the wax die;

removing the wax die to reveal a wax component;

coating the wax component with a ceramic coating to form a ceramic shell with a ceramic core positioned therein;

removing the wax component within the ceramic coating leaving one or more cavities within the ceramic coating;

filling the one or more cavities within the ceramic coating with a molten metal; and

removing the ceramic shell and the one or more ceramic cores to form the turbine component with the inner surface.