Patent Grant
10421119
The present disclosure relates generally to forming components via casting and, more specifically, to an assembly and method for casting perforations directly into a component.
At least some metallic components are formed at least partially by casting. Some casting methods facilitate the production of near net shaped components where the component is substantially formed in one step during the casting process and finish machined to complete the component. For example, but not by way of limitation, some components, such as hot gas path components of gas turbines, are subjected to high temperatures. At least some such components have intricate shapes and contours such as, but not limited to, surface features for promoting cooling and structures to promote mixing of fluid streams.
At least some such known components are formed in a mold having a cavity that defines the external shape of the component. A molten metal alloy is introduced to the cavity of the mold and, in some methods, around a ceramic core, and cooled to form the component. However, an ability to produce an intricate near net component depends on an ability to precisely define the pattern used to create the mold. At least some known patterns are fragile, resulting in patterns and/or cores that are difficult and expensive to produce and handle without damage during the mold creation and casting process.
Alternatively or additionally, at least some known components are formed by drilling and/or otherwise machining the component to obtain the final shape, such as, but not limited to, using an electrochemical machining process. However, at least some such machining processes are relatively time-consuming and expensive. Moreover, at least some such machining processes cannot produce an outer wall having the features, shape, and/or contours required for certain component designs.
In one aspect, a method of forming a component is provided. The method includes coupling an array of receptacles to a mold core. Each receptacle in the array contains an amount of uncured mold material. The method further includes forming a layer of fugitive material on the mold core such that the array of receptacles is encapsulated within the layer of fugitive material, and forming a layer of uncured mold material on the layer of fugitive material, thereby forming an uncured mold assembly. The uncured mold assembly is heated to a temperature that solidifies the uncured mold material within each receptacle and of the layer, thereby forming an array of pins and a layer of solidified mold material, and heated to the temperature that removes the layer of fugitive material from between the mold core and the layer of solidified mold material such that a mold cavity including the array of pins is defined therebetween.
In another aspect, a mold assembly is provided. The mold assembly includes a mold core, an array of receptacles coupled to the mold core. Each receptacle in the array contains an amount of uncured mold material. A layer of fugitive material is formed on the mold core such that the array of receptacles is encapsulated within the layer of fugitive material, and a layer of uncured mold material is formed on the layer of fugitive material.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
Embodiments of the present disclosure relate to an assembly and method for casting perforations directly into a component. More specifically, the assembly includes an array of receptacles, where each receptacle in the array receives uncured mold material therein. The array is coupled to a ceramic mold core, encapsulated in a layer of fugitive material, and a layer of uncured mold material is formed over the layer of fugitive material. When heated, the fugitive material and the material used to form the array of receptacles are removed from between the ceramic mold core and the layer of uncured mold material. In addition, the uncured mold material solidifies such that a mold cavity for receiving component material in a fluid state is defined between the ceramic mold core and the layer of now solidified mold material. The uncured mold material in the receptacles likewise solidifies such that an array of pins is formed between the ceramic mold core and the layer of solidified mold material. As such, when the component material is introduced into the mold cavity, the array of pins facilitates forming perforations in the cast component. As such, the perforations are formed in the cast component in a quick, efficient, and cost effective manner.
In operation, air entering turbine engine 10 through intake 24 is channeled through fan assembly 12 towards booster compressor assembly 14. Compressed air is discharged from booster compressor assembly 14 towards high-pressure compressor assembly 16. Highly compressed air is channeled from high-pressure compressor assembly 16 towards combustor assembly 18, mixed with fuel, and the mixture is combusted within combustor assembly 18. High temperature combustion gas generated by combustor assembly 18 is channeled towards turbine assemblies 20 and 22. Combustion gas is subsequently discharged from turbine engine 10 via exhaust 26.
In one embodiment, mold core 102 and the uncured mold material are formed from the same material, which is any material that enables mold assembly 100 to function as described herein. An exemplary material used to form mold core 102 and the uncured mold material includes, but is not limited to, a ceramic material. As such, as will be explained in more detail below, mold core 102 and the uncured mold material are combined when heated 116 to a predetermined curing temperature, thereby forming a solidified mold assembly 118.
In addition, the fugitive material is any material that enables mold assembly 100 to function as described herein. An exemplary fugitive material includes, but is not limited to, a wax material. In the exemplary embodiment, the wax material has a vaporization temperature lower than the predetermined curing temperature of the ceramic material used to form mold core 102 and the uncured mold material. As such, as will be explained in more detail below, layer 108 of fugitive material is removed from between mold core 102 and layer 110 of uncured mold material when mold assembly 100 is heated to the predetermined curing temperature, thereby defining a mold cavity 112 within solidified mold assembly 118.
In the exemplary embodiment, array 104 includes a plurality of receptacles 106, and a plurality of spacing members 114 extending between receptacles 106 in array 104 such that receptacles 106 are interconnected. Moreover, the plurality of spacing members 114 are oriented in one or more dimensions for arranging receptacles 106 in a predetermined layout on mold core 102. For example, in one embodiment, mold core 102 is a contoured object, and array 104 of receptacles 106 is extended about mold core 102 in more than one dimension. As such, array 104 is quickly and easily positionable on mold core 102 when forming mold assembly 100. Alternatively, spacing members 114 are omitted from array 104, and receptacles 106 are individually positionable on mold core 102 when forming mold assembly 100.
Array 104, including receptacles 106 and spacing members 114, is fabricated from any material and in any manufacturing process that enables mold assembly 100 to function as described herein. In one embodiment, array 104 is at least partially fabricated in an additive manufacturing process. Exemplary materials used to fabricate array 104 include, but are not limited to, metallic material, polymeric material, and a combination thereof. The metallic material has a vaporization temperature greater than the predetermined curing temperature of the ceramic material used to form mold core 102 and the uncured mold material. As such, as will be explained in more detail below, array 104 remains positioned within mold cavity 112 as the uncured mold material contained therein is heated and solidifies, and the metallic material is configured for absorption into a metallic component material when introduced into mold cavity 112 of solidified mold assembly 118.
In addition, the polymeric material has a vaporization temperature lower than the predetermined curing temperature of the ceramic material. As such, as will be explained in more detail below, array 104 is removed from mold cavity 112 concurrently as the uncured mold material contained therein is heated and solidifies. When formed from the combination of metallic material and polymeric material, receptacles 106 are formed from polymeric material, an interior (not shown) of receptacles 106 are coated with metallic material. For example, in some embodiments, receptacles 106 are coated in an electroplating or electro-less plating process. As such, the shape of the uncured mold material within receptacles 106 is maintained by the metallic material as the polymeric material is removed from mold cavity 112.
As described above, mold assembly 100 is heated 116 to facilitate solidifying the uncured mold material contained within receptacles 106 and of layer 110 of uncured mold material, thereby forming solidified mold assembly 118. In addition, heating 116 mold assembly 100 facilitates vaporizing layer 108 of fugitive material for removal from solidified mold assembly 118. As such, solidified mold assembly 118 is formed from a unitary structure including mold core 102, a layer 120 of solidified mold material, and an array of pins 122 extending therebetween. In one embodiment, receptacles 106 in array 104 are shaped for extending linearly between mold core and layer 120 of solidified mold material, such that perforations having a linear orientation are formed in the component being formed (i.e., turbine blade 30). Moreover, in the exemplary embodiment, receptacles 106 in array 104 have an open top such that the uncured mold material in receptacles 106 and of layer 110 are combined when heated 116.
Moreover, removing layer 108 of fugitive material from solidified mold assembly 118 facilitates defining mold cavity 112 between mold core 102 and layer 120 of solidified mold material. A metallic component material 124 in a fluid state is then introduced 126 into mold cavity 112 of solidified mold assembly 118. The metallic component material 124 is allowed to cool and solidify within solidified mold assembly 118, thereby forming a cast component such as turbine blade 30. As such, in the context of turbine blade 30, mold core 102 corresponds to internal flow passage 40 (shown in
The assemblies and methods described herein facilitate the formation of metallic cast components or objects having an array of perforations or cooling holes defined therein. Rather than casting the object and subsequently forming cooling holes therein, the mold assemblies described herein include an array of pins within a mold cavity of the assemblies. More specifically, the array of pins is formed by curing ceramic material in an array of receptacles in situ. A component material is then introduced into the mold cavity, and cooling holes are formed in the cast component in positions voided by the array of pins. As such, components having perforations or cooling holes defined therein are manufactured in a quick, efficient, and cost effective manner.
An exemplary technical effect of the assemblies and methods described herein includes at least one of: (a) forming a mold assembly that facilitates forming components having cast in perforations or cooling holes; (b) forming perforations or cooling holes having complex geometries within cast components; and (c) reducing the time and effort of forming perforations or cooling holes in a cast component.
Exemplary embodiments of investment casting assemblies and methods are provided herein. The assemblies and methods are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the configuration of components described herein may also be used in combination with other processes, and is not limited to practice with only manufacturing turbine components, as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many applications where forming cast components having perforations or cooling holes is desired.
Although specific features of various embodiments of the present disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of embodiments of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the embodiments of the present disclosure, including the best mode, and also to enable any person skilled in the art to practice embodiments of the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
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| Number | Date | Country | |
|---|---|---|---|
| 20180185913 A1 | Jul 2018 | US |
