Method for integrating a direct printing mold for

Abstract

A method of optimizing strength in an improved mold (100) for casting a component (55) is provided. The method may include the steps of: evaluating a defect (90) in an existing mold (88); adding an external reinforcement feature (120) to the design of the improved mold (100); manufacturing an improved mold (100) in an additive manufacturing process; and casting the cast part (55) in the improved mold (100).

Description

Technical Field

[0001] The present application and the resulting patent relate generally to casting components, such as cast parts, cast components, cast gas parts, etc., and more particularly to improved methods and systems for direct printing molds with integrated fixed reinforcements to produce castings of components in an efficient and accurate manner. Background Art

[0002] Gas turbine engines typically include a compressor for compressing ambient air and a plurality of burners for mixing an air flow with a fuel flow to produce hot combustion gases. The turbine receives the hot combustion gas flow and extracts energy from it to provide power to the compressor and produce output power for external loads such as generators. Hot gas path components of gas turbine engines, such as turbine airfoils, are traditionally manufactured using an investment casting process. In this method, a molten metal alloy is introduced into a mold cavity defined between a shell and a core and solidified to form a finished casting. Depending on the application, turbine components may need to withstand thermal stresses caused by high temperatures, centrifugal forces, and large temperature fluctuations. Therefore, turbine components may include internal cooling passages and other types of complex geometries.

[0003] Conventional molding techniques for manufacturing turbine components can be time consuming and / or can limit the resolution of the mold and / or core. In addition, the shell formed after slurry infusion can limit heat transfer. In contrast, additive manufacturing techniques and 3-D printing allow the first mold to be manufactured in a fast and efficient manner. However, the harshness of manufacturing highly complex shapes and / or multiple process steps between printing and casting can cause stress characteristics that lead to cracking or deformation of the additively manufactured mold. Previous attempts to strengthen such molds have focused on developing mold compositions and firing processes to slow the progress of burnout. Similarly, other attempts have used designs with internal recesses with different types of inserts. However, the use of such inserts increases the time and cost of the manufacturing process. Summary of the invention

[0004] The present application and the resulting patent provide a method for optimizing the strength of an improved mold for a cast component. The method may include the following steps: evaluating defects in an existing mold; adding external reinforcement features to the design of the improved mold; manufacturing the improved mold in an additive manufacturing process; and casting the cast component in the improved mold.

[0005] The present application and the resulting patent may also provide a mold for casting a component. The mold may include a component body of a ceramic material made by an additive manufacturing process and one or more external reinforcement features manufactured in the component body.

[0006] These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon reading the following detailed description, taken in conjunction with the several drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of a gas turbine engine including a compressor, a combustor, a turbine, and an external load.

[0008] Figure 2 A perspective view of a turbine blade.

[0009] Figure 3 is a perspective view of an exemplary turbine component firing mold having defects.

[0010] Figure 4 is a perspective view of an exemplary turbine component firing mold having external reinforcement features.

[0011] Figure 5 is a perspective view of a turbine component mold with additional external reinforcement features.

[0012] Figure 6 is a perspective view of a turbine component mold with additional external reinforcement features.

[0013] Figure 7 is a flow chart of exemplary process steps for producing a turbine component mold having external reinforcement features. DETAILED DESCRIPTION

[0014] Referring now to the drawings, in which like numerals refer to like elements throughout the several views, Figure 1 A schematic diagram of a gas turbine engine 10 as described herein is shown. The gas turbine engine 10 may contain a compressor 15. The compressor 15 compresses an incoming air flow 20. The compressor 15 delivers the compressed air flow 20 to a plurality of combustor cans 25. The combustor cans 25 mix the compressed air flow 20 with a pressurized fuel flow 30 and ignite the mixture, thereby producing a hot combustion gas flow 35. Although only a single combustor can 25 is shown, the gas turbine engine 10 may include any number of combustor cans 25 positioned in a circumferential array or the like. Alternatively, the combustor 25 may be an annular combustor. The combustion gas flow 35 is then delivered to a turbine 40. The combustion gas flow 35 drives the turbine 40 to produce mechanical work. The mechanical work produced in the turbine 40 drives the compressor 15 through a rotor shaft 45. The turbine 40 and the rotor shaft 45 may also drive an external load 50 such as a generator.

[0015] The gas turbine engine 10 can use natural gas, hydrogen, various types of synthetic gas, liquid fuels and / or other types of fuels and blends thereof. The gas turbine engine 10 can be any of a variety of different gas turbine engines provided by General Electric Company of Schenectady, New York, including but not limited to those of heavy-duty gas turbine engines such as the 7 series or 9 series. The gas turbine engine 10 can be part of a single cycle or combined cycle power generation system or other types of power generation systems. The gas turbine engine 10 can have different configurations and can use other types of components. Other types of gas turbine engines can also be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment can also be used together herein.

[0016] Figure 2 An example of a turbine component 55 that can be used with the turbine 40 is shown. In this example, the turbine component 55 can be a turbine blade 56. Generally speaking, the turbine blade 56 includes an airfoil 60, a shank portion 65, and a platform 70 disposed between the airfoil 60 and the shank portion 65. The airfoil 60 generally extends radially outward from the platform 70 and includes a leading edge 72 and a trailing edge 74. The airfoil 60 may also include a concave wall defining a pressure side 76 and a convex wall defining a suction side 78. The platform 70 may be substantially horizontal and planar. The platform 70 may be exposed to the flow of hot combustion gases 35. The shank portion 65 may include a shank cavity 80 therein. The shank portion 65 may also include one or more angel wings 82 and a root structure 84, such as a dovetail or the like. The root structure 84 may be configured to secure the turbine blade 56 to the rotor disk.

[0017] The turbine blade 56 may include one or more cooling circuits 86 extending therethrough to flow a cooling medium such as air from the compressor 15 or from another source. The cooling circuits 86 and the cooling medium may circulate at least through portions of the airfoil 60, the shank portion 65, and the platform 70 in any order, direction, or route to form a cooling medium flow path. Many different types of turbine components 55 may be used herein. The turbine blade 56 defined herein is for exemplary purposes only. Other components and other configurations may also be used herein.

[0018] Additive manufacturing techniques for producing turbine component castings generally include multiple process steps. These steps may include mold design via a CAD process, printing the mold via a ceramic slurry, preparing the mold via evacuation, cleaning, and firing the mold. However, these steps may create stress concentrations and other defects in the mold. This is especially true during the firing step, which can place a lot of stress on the ceramic component and can cause cracking and dimensional inconsistencies. For example, Figure 3 An existing airfoil firing mold 88 produced by an additive manufacturing process is shown. As shown, the airfoil mold 88 has collapsed during the firing step. This collapse is considered a defect 90 in the overall mold design. Another defect 96 is a crack formed in any wall of the mold 88.

[0019] Figure 4 A turbine component firing mold 100 is shown, which is made of a ceramic 110 from a slurry in an additive manufacturing process. The additive manufacturing process can utilize optimization of the external features of the mold, for example, to improve mold strength, or to impart microstructural progression in any position during the mold manufacturing process by adding external reinforcement features 120 to the component body 125. For example, the external reinforcement features 120 of the turbine component firing mold 100 may include external ribs 130 to the airfoil portion 140 of the turbine component mold 100. The external ribs 130 may extend in a vertical or horizontal direction or in any nearby direction. The external ribs 130 may be placed on the surface in any shape / form calculated by structural methods and verified by experience. Likewise, the size and shape of the external ribs 130 may vary depending on the application. Adding external ribs 130 to the turbine component mold 100 allows the turbine component mold 100 to maintain the desired dimensional consistency during the firing step, etc. External ribs 130 and other types of external reinforcement features 120 help to more evenly distribute stresses during 3D printing and post-printing processing to improve the overall stiffness and strength of the turbine component mold 100. Traditionally, the exterior surface of the mold has been largely neglected, namely due to multiple shell recesses and uniformly thick shells.

[0020] These external reinforcement features 120 can be designed into a CAD program for mold printing, for example, through methods and principles of topology optimization (TPO) used in various engineering disciplines and computational mechanics. TPO is a method for optimizing the distribution of materials within a given design space (e.g., 3D casting) to achieve specific performance goals (e.g., strengthening the shell exterior for ease of handling, minimizing internal cracks in fired microstructures, etc.).

[0021] Specifically, topology optimization is a mathematical method that optimizes the material layout within a given design space with the goal of maximizing the performance of the system for a given set of loads, boundary conditions, and constraints. Topology optimization differs from shape optimization and size optimization in that the design can achieve any shape within the design space rather than dealing with predefined configurations. Conventional topology optimization formulations use the finite element method (FEM) to evaluate the design performance. Many different TPO systems are currently available.

[0022] Figure 5 and Figure 6Another example of a turbine component firing mold 100 is shown. In these examples, a turbine blade mold 150. The turbine blade mold 150 can be a combined core and shell 155, etc. Figure 5 In the example of FIG. 1 , only the shank portion 160 of the turbine blade mold 100 has the external ribs 130. Figure 6 In the example of , both the shank portion 160 and the airfoil portion 140 have external ribs 130. In addition, the shank portion 160 and / or the base portion 170 (inverted cup region) may also include a plurality of gussets 180 formed therein. The use of the external ribs 130 can greatly strengthen the airfoil portion 140 of the turbine blade mold 150, thereby strictly controlling deformation therein. Likewise, the use of the gussets 180 increases the rigidity of the shank portion 160 and the base portion 170 for optimal upright positioning of the turbine component mold 100 during firing and other process steps.

[0023] Other areas of topology optimization may include enhanced corners and edges 190. Such corners and edges 190 may typically be high stress areas in the turbine component mold 100. Topology optimization may enhance these areas by adding material to enhance resistance to deformation and cracking. Topology optimization may also eliminate stress concentration points in the overall geometry of the turbine component mold 100. By redistributing the ceramic slurry material 110, the turbine component mold 100 may become more resilient and less prone to failure in critical areas.

[0024] Similarly, the topology optimization process can identify the load-bearing areas 200 that are subject to the greatest stresses during the casting process (based on the casting geometry and melt characteristics). These load-bearing areas 200 can be strengthened and optimized to withstand higher pressures and maintain shape integrity by reducing creep during the casting process. Likewise, fillets 210 (i.e., rounded corners or edges) can be used to smooth transitions between different surfaces in the turbine component mold 100. Topology optimization can optimize the size and shape of the fillets 210 to minimize stress concentrations and enhance overall mold strength.

[0025] Other issues may include the total material thickness 220. Topology optimization can help identify areas where the material thickness 220 can be increased or decreased. These changes enable the turbine component mold 100 to be more efficient in terms of material usage while maintaining or even improving the overall structural integrity. Similarly, the optimization process can be used to customize the external structure of the turbine component mold 100 to provide anisotropic properties, i.e., different mechanical properties along different directions. Such properties may be beneficial for applications where directional strength is critical. The specific features and designs resulting from topology optimization will vary based on the intended application, load conditions, and manufacturing constraints. The optimization process takes these factors into account to achieve the most appropriate and effective design for the external reinforcement features 120 and the turbine component mold 100.

[0026] Therefore, the use of external reinforcement features 120 on the turbine component mold 100 speeds up and improves the entire casting process. The process steps of CAD design, printing, firing, casting and finishing are all simplified and more efficient. The combination of additive manufacturing and local optimization provides the required stiffness of those areas of the turbine component mold 100 that may be prone to cracking or deformation. Likewise, the external reinforcement features 120 allow the turbine component mold 100 to stand stably in any firing orientation. In addition, the overall design of the turbine component mold 100 can be quickly changed to take into account specific applications and / or customizable designs.

[0027] Figure 7 2 is a flow chart showing exemplary steps in a method of maximizing the design of a turbine component mold 100 to minimize production defects. In step 230, a portion of the turbine component mold 100 having a defect 90 is determined. For example, a crack in the airfoil portion 140. In step 240, the nature of the defect 90 is determined. For example, a crack. In step 250, a topology optimization process can be applied to generate an external enhancement feature 120 to address the defect 90. For example, the external enhancement feature 120 can be an external rib 130 or other structure to reduce stress concentration and accommodate changes in load-bearing area and material thickness. In step 260, a design of a modified or improved turbine component mold 100 can be generated in a CAD process or the like. In step 270, the improved turbine component mold 100 can be generated in an additive manufacturing process. In step 280, the turbine component mold 100 can be fired. In step 290, the turbine component mold 100 can be used for casting. Other and different process steps can be used here.

[0028] It will be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the appended claims and their equivalents.

[0029] Further aspects of the invention are provided by the subject matter of the following clauses:

[0030] 1. A method of optimizing strength in an improved mold for a cast component, the method comprising: evaluating defects in an existing mold; adding external reinforcement features to the design of the improved mold; manufacturing the improved mold in an additive manufacturing process; and casting the cast component in the improved mold.

[0031] 2. A method according to any preceding clause, wherein the step of adding external reinforcing features to the design of the modified mould comprises adding external ribs to sections of the modified mould.

[0032] 3. A method according to any preceding clause, wherein the cast component is a turbine component and the step of adding external reinforcement features to the design of the modified mould comprises adding external ribs to at least one of the airfoil portion and the shank portion of the modified mould.

[0033] 4. A method according to any preceding clause, wherein the step of adding external reinforcing features to the design of the modified mould comprises adding gussets to a base portion and / or a handle portion of the modified mould.

[0034] 5. A method according to any preceding clause, wherein the cast component is a turbine component and the step of adding external reinforcement features to the design of the modified mould comprises adding fillets around an airfoil portion of the modified mould.

[0035] 6. A method according to any preceding clause, wherein the step of adding external reinforcement features to the design of the modified mould comprises adding external reinforcement features to a load-bearing area of ​​the modified mould.

[0036] 7. A method according to any preceding clause, wherein the step of adding external reinforcement features to the design of the improved mould comprises a topology optimisation process.

[0037] 8. A method according to any preceding clause, wherein the topology optimization process reduces stress concentrations in the improved mold compared to existing molds.

[0038] 9. A method according to any preceding clause, wherein the step of manufacturing the improved mould in an additive manufacturing process comprises using a ceramic material.

[0039] 10. A method according to any preceding clause, wherein the topology optimization process comprises redistributing ceramic material in the modified mold.

[0040] 11. A method according to any preceding clause, wherein the topology optimization process comprises varying the thickness of the ceramic material in the modified mold.

[0041] 12. A method according to any preceding clause, further comprising firing the modified mould.

[0042] 13. A method according to any preceding clause, wherein the step of adding external reinforcement features to the design of the modified mould comprises a computer aided design process.

[0043] 14. A method according to any preceding clause, wherein the improved mould comprises a combined core and shell.

[0044] 15. A mold for casting a component, the mold comprising: a component body; wherein the component body comprises a ceramic material made by an additive manufacturing process; and one or more external reinforcement features manufactured in the component body.

[0045] 16. A mould for a cast component according to any preceding clause, wherein the one or more external reinforcement features comprise external ribs.

[0046] 17. A mould for a cast component according to any preceding clause, wherein the cast component is a turbine component and the component body comprises at least one of an airfoil portion and a shank portion and the one or more external reinforcement features comprise external ribs.

[0047] 18. A mould for a cast component according to any preceding clause, wherein the one or more external reinforcement features comprise gussets.

[0048] 19. A mould for a cast component according to any preceding clause, wherein the one or more external reinforcement features comprise fillets.

[0049] 20. A mould for casting a component according to any preceding clause, wherein the one or more external reinforcement features comprise external ribs, gussets and / or fillets.

Claims

1. A method of optimizing strength in an improved mold (100) for casting a component (55), the method comprising: evaluating defects (90) in existing molds (88); adding external reinforcement features (120) to the design of the improved mold (100); manufacturing the improved mold (100) in an additive manufacturing process; as well as The cast component (55) is cast in the improved mold (100).

2. The method of claim 1, wherein the step of adding external reinforcement features (120) to the design of the modified mold (100) comprises adding external ribs (130) to a section (140) of the modified mold (100).

3. The method of claim 1, wherein the cast component is a turbine component (55), and the step of adding external reinforcement features (120) to the design of the modified mold (100) includes adding external ribs (130) to at least one of an airfoil portion (140) and a shank portion (160) of the modified mold (100).

4. The method of claim 1, wherein the step of adding an external reinforcement feature (120) to the design of the modified mold (100) comprises adding a gusset (180) to a base portion (170) and / or a handle portion (160) of the modified mold (100).

5. The method of claim 1, wherein the cast component is a turbine component (55), and the step of adding external reinforcement features (120) to the design of the modified mold (100) includes adding an inner fillet (210) around an airfoil portion (140) of the modified mold (100).

6. The method of claim 1, wherein the step of adding external reinforcement features (120) to the design of the modified mold (100) comprises adding external reinforcement features (120) to a load-bearing area (200) of the modified mold (100).

7. The method of claim 1, wherein the step of adding external reinforcement features (120) to the design of the improved mold (100) comprises a topology optimization process.

8. The method of claim 7, wherein the topology optimization process reduces stress concentrations in the improved mold (100) compared to an existing mold (88).

9. The method of claim 7, wherein the step of manufacturing the improved mold (100) in an additive manufacturing process comprises using a ceramic material (110).

10. The method of claim 9, wherein the topology optimization process includes redistributing the ceramic material (110) in the modified mold (100).

11. The method of claim 10, wherein the topology optimization process comprises varying the thickness of the ceramic material (110) in the modified mold (100).

12. The method of claim 1, further comprising firing the improved mold (100).

13. The method of claim 1, wherein the improved mold (100) comprises a combined core and shell (155).

14. A mold (100) for casting a component (55), the mold comprising: Component body (125); wherein the component body (125) comprises a ceramic material (110) made by an additive manufacturing process; and One or more external reinforcement features (120) fabricated in the component body (125).

15. The mold for casting a component according to claim 14, wherein the one or more external reinforcement features include external ribs (130), gussets (180), and / or fillets (210).

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