Protection system with gasket for ceramic core processing operation and related method

A protection system for preventing foreign material from lodging in a channel between and/or damage to adjacent ceramic core features during a core processing operation is disclosed. The system includes a gasket sized and shaped to self-lock within the channel and prevent foreign material from lodging within the channel during the core processing operation. A method may include determining a geometrical characteristic of the channel and adjacent ceramic core feature; fabricating a gasket to fit and self-lock within the channel; positioning the gasket within the channel; and performing the core processing operation. The gasket prevents the foreign material from lodging in the channel, reducing subsequent damage to the ceramic core compared to the channel without the gasket.

BACKGROUND OF THE INVENTION

The disclosure relates generally to investment casting, and more particularly, to a protection system for a ceramic core for core processing operations, and a related method.

Investment casting is used to manufacture a large variety of industrial parts such as turbomachine blades. Investment casting uses a casting article having a sacrificial material pattern to form a ceramic mold for the investment casting. Certain types of casting articles may include a ceramic core or insert within the sacrificial material pattern. The ceramic core is used to create a hollow structure in a final metal component, and may define an interior structure of the component. The ceramic core is a part of the ceramic mold used during the investment casting. Ceramic core(s) can include a large variety of intricate features that define an interior structure of the component, e.g., a number of cooling passages within a turbomachine blade. Ceramic cores can be cast, or additively manufactured to allow for rapid prototyping and manufacturing of the cores. The casting article is made by molding a sacrificial material fluid, such as hot wax or a polymer, about the ceramic core while it is positioned in a ceramic mold that defines the shape of the component surrounding the ceramic core. The hardened sacrificial material formed about the ceramic core defines the shape of the component for the investment casting. Each casting article, whether individually or in a collection of casting articles, can be dipped in a slurry and coated with a ceramic to form a ceramic mold for the investment casting. Once the sacrificial material is removed from the ceramic mold, the ceramic mold with the ceramic core therein can be used to investment cast the component using a molten metal, e.g., after pre-heating the ceramic mold. Once the molten metal has hardened, the ceramic mold can be removed, and the ceramic core can be removed using a leachant. The component can then be finished in a conventional fashion, e.g., heat treating and conventional finishing.

Investment casting is a time consuming and expensive process, especially where the component must be manufactured to precise dimensions. In particular, where precise dimensions are required, formation of the casting article must be very precise. Each mold used to form the casting article can be very costly, and can take an extensive amount of time to manufacture. Consequently, any changes or flaws in the ceramic core or the component can be very expensive and very time consuming to address.

Certain core processing operations present challenges during the overall investment casting process. One core processing operation that poses issues is referred to as ‘rework’ of the ceramic core after its formation, e.g., through casting or additive manufacturing. The rework may include removal of material or addition of material to the ceramic core. For example, supports used during the formation of the ceramic core may need to be removed, or ceramic core features must be built up by addition of ceramic to provide a desired shape. The rework of the ceramic core can be very challenging where the ceramic core includes open areas that must remain open despite rework processing that creates foreign material such as but not limited to: ceramic debris from removal processing, or excess ceramic slurry from additive processing. For example, a channel on an exterior surface of the ceramic core may be used to create a rib in a final metal component, and is one type of structure that is commonly located on an exterior surface of a ceramic core. In some instances, a channel may pass around a boss or other raised structure in its path. The boss may be provided to support an internal structure of the ceramic core. Due to the size and intricacy of the channel extending around the boss or other raised structure, it is oftentimes impossible to prevent foreign material from entering the channel during rework. In these instances, very delicate repair completed by a highly experienced technician may be necessary, or the core may have to be scrapped. Both results are ideally avoided because of their time consumption and expense.

Casting with ceramic cores that include intricate or delicate ceramic core features can also pose a challenge. For example, intricate ceramic cores, such as those for a serpentine cooling passage in a turbomachine airfoil, may include very small ceramic core features that may break or otherwise be deformed from their intended shape during formation or rework. In some instances, rework of these very small ceramic core features is extremely difficult or impossible. In these instances, a ceramic core may need to be scrapped, which adds expense to the process.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of the disclosure provides a protection system for preventing a foreign material from lodging in a channel between and/or damage to adjacent ceramic core features during a core processing operation, the protection system comprising: a gasket sized and shaped to self-lock within the channel between adjacent ceramic core features in a ceramic core and prevent foreign material from lodging within the channel during the core processing operation.

A second aspect of the disclosure provides a method of preventing a foreign material from lodging in a channel between and/or damage to adjacent ceramic core features during a core processing operation, the method comprising: determining a geometrical characteristic of the channel and adjacent ceramic core feature; fabricating a gasket to fit and self-lock within the channel; positioning the gasket within the channel; and performing the core processing operation, wherein the gasket prevents the foreign material from lodging in the channel and damage to adjacent core features, reducing subsequent damage to the ceramic core compared to the channel without the gasket.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the disclosure provides a protection system for preventing foreign material from lodging in a channel between and/or damage to adjacent ceramic core features during a core processing operation. The protection system includes a gasket sized and shaped to self-lock within the channel between adjacent ceramic core features in a ceramic core and prevent foreign material from lodging within the channel during the core processing operation. A method may include determining a geometrical characteristic of the channel and adjacent ceramic core feature; fabricating a gasket to fit and self-lock within the channel; positioning the gasket within the channel; and performing the core processing operation. The gasket prevents the foreign material from lodging in the channel, reducing subsequent damage to the ceramic core compared to the channel without the gasket. The ceramic core processing may include rework, e.g., removal or addition of ceramic from the core, but also may include the actual casting of the component using the ceramic core as part of a casting article with the gasket in-place.

Referring toFIG. 1, an illustrative ceramic core10is shown. As understood in the field, ceramic cores can be used to form a large variety of final metal components during investment casting. Embodiments of the disclosure are described herein using multiwall airfoils of a turbomachine blade as example components.FIG. 2shows a cross-sectional view of a multiwall airfoil22formed using ceramic core10. Ceramic core10is used during the casting process of multiwall airfoil22(FIG. 2) in a conventional fashion, e.g., to form a casting article with a sacrificial material before exterior ceramic slurry formation for the ceramic mold, and in the ceramic mold during the actual molten metal investment casting. Ceramic core10can be made using any now known or later developed processes, e.g., casting, additive manufacturing, etc. As depicted in detail inFIG. 1, ceramic core10includes one or more center plenum sections24, which are configured to form center plenums124(FIG. 2) of multiwall airfoil22, and a plurality of outer passage sections26, which are configured to form outer cooling passages126(FIG. 2) of multiwall airfoil22. Ceramic core10has an exterior surface28that is at least partially defined by exterior surfaces30of outer cooling passages26.

For purposes of description, one illustrative ceramic core feature to which embodiments of a protection system may be employed is a boss in ceramic core10. More particularly, each center plenum section24includes a center section32, and at least one boss34,36. Boss(es)34,36extend outwardly from center section32of center plenum section24to, but not beyond, exterior surface28of ceramic core10. Each boss34may be located on a “pressure” or concave side of ceramic core10, corresponding to the pressure side of a multiwall airfoil22(FIG. 2) formed using ceramic core10. Similarly, each boss36may be located on the “suction” or convex side of ceramic core10, corresponding to a suction side of a multiwall airfoil22(FIG. 2) formed using ceramic core10. Bosses34,36may be configured to control the position, and prevent the movement of, center plenum sections24during firing during molding of ceramic core10, e.g., when in setter blocks of a shaping mold, or during use of ceramic core10. As shown inFIGS. 1 and 3, each boss34,36may extend outwardly from a respective center plenum section24between a pair of outer passage sections26.

As shown inFIG. 3, each boss34,36may have a substantially elliptical cross-sectional configuration. Each boss34,36may thus have a first vertex46and a second vertex48(axes and co-vertices not labeled). A channel42,44diverges around first vertex46of a respective boss34,36and converges at second vertex48of respective boss34,36. To limit turbulence and pressure loss of coolant flowing through outer cooling passages126in multiwall airfoil22(FIG. 2) corresponding to outer passage sections26(FIG. 1) of ceramic core10on either side of boss(es)34,36, boss(es)34,36may have a length (L on major axis) to width (W on minor axis) ratio of about 3:1 to about 10:1. In a particular embodiment, a length to width ratio of about 7:1 may be used. Although described as elliptical, boss(es)34,36may have any other suitable cross-sectional configuration such as but not limited to: diamond (see e.g.,FIG. 9), polygonal (square, rectangular), circular or oval. Any number of boss(es)34,36may be employed. Channel42,44is elliptical about boss(es)34,36and linear as they extend between boss(es)34,36, and as they extend away from boss(es)34,36.

Embodiments of the disclosure provide a protection system200for preventing a foreign material from lodging in channel42,44between, or otherwise causing damage to, adjacent ceramic core features, e.g., a boss34,36and outer passage sections26, during a core processing operation. “Ceramic core features” can be any ceramic element of the ceramic core (e.g., bosses34,36), which as will be apparent from the embodiments described herein, can vary widely. “Foreign material” can include any matter that can enter a channel as described herein, and change the shape of that channel either temporarily or permanently including but not limited to: blended core material, core fill material, ceramic or other debris or dust, and ceramic slurry. In accordance with embodiments of the disclosure, a protection system200may include, among other things, a gasket202sized and shaped to self-lock within channel42,44and prevent foreign material from lodging within the channel during the core processing operation. As used herein, “channel” can mean any open area between ceramic core features regardless of shape or size. Typically, the channel is an open area intended to be filled by molten metal during the casting process. As will be apparent from the description, the channel can have practically any shape including elliptical, linear and/or curvilinear. Further, “core processing operation” can include any operation relating to the core including but not limited to: rework in which material is added or removed from the core, and/or casting of the final metal component. As noted, rework of ceramic core10to remove or reduce the size of or add material to a ceramic core feature thereof can be challenging, especially in terms of preventing foreign material from lodging in channels42,44, or otherwise preventing damage to ceramic core features. Where exterior surface28includes complicated structure, rework may be impossible without protection system200.

In one embodiment, shown inFIGS. 4-10, gasket202may having an open center body204, i.e., having an open center206, configured to surround at least a portion of at least one ceramic core feature, e.g., a boss34,36, in exterior surface28of ceramic core10.FIGS. 4 and 5show perspective views of embodiments of gaskets202in place in ceramic core10, andFIGS. 6 and 7show perspective views of gaskets202shown inFIGS. 4 and 5, respectively.

Gasket202may have any shape necessary to mate with and self-lock in channel42,44, i.e., prevent it from falling out of the channel on its own. In the example shown inFIGS. 4 and 6, gasket202may have any shape configured to sealingly mate with boss34,36in respective channel42,44so as to prevent foreign material from lodging therein. Here, a respective channel42,44in exterior surface28of ceramic core10surrounds boss34,26, and gasket202fills the channel about the boss. InFIGS. 4 and 6, gasket202has an elliptical shape so as to conform to elliptical bosses34,36, i.e., boss34,36has an elliptical cross-section positioned within the channel. In another example shown inFIGS. 5, 7 and 8, gasket202further includes a first elongate member212extending from open center body204, and a second elongate member214extending from open center body204. Elongate members212,214are configured to fill a portion of channel42,44extending away from a respective boss34,36. First elongate member212may have a first length and second elongate member214may have a second length different than the first length. However, they may have the same length, if desired. As shown inFIGS. 5 and 8, open center body204, first elongate member212and second elongate member214fit within channel42,44in exterior surface28of ceramic core10. Here, open center body204includes an elliptical body218having open center206for self-locking in an elliptical channel portion220of channel42,44about elliptical boss34,36. Further, as shown inFIG. 5, first elongate member212extends from a first vertex222of elliptical body218for self-locking in a first elongate channel portion224of channel42,44, and second elongate member214extends from a second vertex226of elliptical body218for self-locking in a second elongate channel portion228of channel42,44. Elliptical body218prevents foreign material from lodging in channel42,44about, or other damage to, a respective boss34,36, and elongate members212,214prevent foreign material from lodging in, or other damage to, channel42,44as it extends away from a respective boss34,36.

Gasket202may have any cross-sectional shape desired, but in most cases is configured to mate with a shape of, and self-lock in, channel42,44. In the examples shown, gasket202has a polygonal cross-section, e.g., square or rectangular, but it could be, for example, elliptical, oval, circular, etc. Typically, gasket202(e.g., open center body204(elliptical body218) and, if provided, first elongate member212and second elongate member214) each have a polygonal cross-section configured to self-lock in a cross-section of channel42,44in exterior surface28of ceramic core10.

FIGS. 9 and 10show another embodiment, similar to that ofFIGS. 4-8, but having a differently shaped inner ceramic core feature34,36in the form of a boss34,36that is diamond shaped. Here, gasket202has an open center body204that his diamond shape.

FIG. 11shows another example of a different form of a channel240between ceramic core features in the form of elements234,236, and a post242. More particularly, ceramic core features include two elements234,236separated by channel240, and post242extending between elements234,236. InFIG. 11, gasket202prevents foreign material from lodging within channel240near post242by having gasket202self-lock in channel240by engaging about post242. Gasket202may have a split tubular configuration so to allow expansion about post242for positioning.

FIGS. 12-14show another embodiment of gasket202. Here, ceramic core features are the same as they are inFIGS. 4-5, e.g., an elliptical boss34,36within channel42,44(FIG. 4). However, in this embodiment, gasket202includes a cover250configured to cover a portion of a ceramic core feature, e.g., elliptical boss34,36, adjacent channel42,44(FIG. 14), and a channel engaging portion252(FIG. 13) extending from cover250(and optionally first and second elongate members212,214) to self-lock in at least a portion of channel42,44. In this example, gasket202further includes first elongate member212extending from cover250, and a second elongate member214extending from cover250. Elongate members212,214are configured to fill a portion of channel42,44extending away from a respective boss34,36. First elongate member212may have a first length and second elongate member214may have a second length different than the first length. However, they may have the same length, if desired. However, elongate members212,214are optional. As shown inFIG. 14, cover250covers boss34,36, and channel engaging portion252(with first elongate member212and second elongate member214, if provided) fit within channel42,44in exterior surface28of ceramic core10. Here, channel engaging portion252includes an elliptical body254for self-locking in an elliptical channel portion220of channel42,44about elliptical boss34,36. Further, first elongate member212extends from a first vertex222of cover250for self-locking in first elongate channel portion224of channel42,44, and second elongate member214extends from a second vertex226of cover250for self-locking in a second elongate channel portion228of channel42,44. Here, gasket202prevents foreign material from lodging in channel42,44and prevents foreign material from lodging on a respective boss34,36, and elongate members212,214prevent foreign material from lodging in channel42,44as they extend away from a respective boss34,36. Gasket202also prevents other damage, e.g., from hits with hard surfaces, etc.

FIG. 15shows a plan view of another illustrative ceramic core310having different ceramic core features compared to that of previous embodiments. Ceramic core310may be used for casting, for example, a cooling circuit geometry for a turbomachine tip shroud cooling geometry, such as described in U.S. Pat. No. 7,686,581, which is hereby incorporated by reference. In this example, ceramic core310includes ceramic, curvilinear core features312,314,316,318and320that may each form part of the cooling circuit. Ceramic core310has an exterior surface328made up, at least in part, by ceramic core features312,314,316,318,320. Channel340has a complex, oblong, curvilinear shape with portions that are linear, e.g., portion340A.FIG. 15also shows a defect322on ceramic core feature312, which requires rework that may cause foreign material to enter channel340or damage to adjacent core features316,318during the rework operation.FIGS. 16 and 17show plan views of gaskets302and402that may be used to prevent foreign material from lodging in channel340(FIG. 15), and/or to prevent other damage.FIG. 16shows an embodiment in which gasket302includes an open center body304(with open center306) configured to surround at least one ceramic core feature, e.g.,312, in an exterior surface328of ceramic core310. Open center body304may have any size and shape configured to mate and self-lock in channel340(FIG. 15).FIG. 17shows gasket402with a cover450configured to cover a portion of a ceramic core feature, e.g.,312, adjacent channel340, and a channel engaging portion452extending from cover450to self-lock in at least a portion of channel340(FIG. 15).FIG. 18shows a cross-sectional view along line18-18inFIG. 17showing cover450and channel engaging portion452. Channel engaging portion452may have any size and shape configured to mate and self-lock in channel340(FIG. 15). While cover450is shown to have a similar shape to that of channel340(FIG. 15), that is not necessary in all instances, e.g., it may cover at least portions of other ceramic core features than just feature312(FIG. 15).

FIG. 19shows a plan view of another embodiment of a gasket502, andFIG. 20shows a cross-sectional view along line20-20inFIG. 19. Here, gasket502is similar to gasket302, shown inFIG. 16. For example, gasket502includes a cover550configured to cover a portion of a ceramic core feature, e.g.,312, adjacent channel340(FIG. 15), and a channel engaging portion552extending from cover550to self-lock in at least a portion of channel340(FIG. 15). Channel engaging portion552may have any size and shape configured to mate and self-lock in channel340(FIG. 15). While cover550is shown to have a similar shape to that of channel340(FIG. 15), that is not necessary in all instances, e.g., it may cover at least portions of other ceramic core features than just feature312(FIG. 15). In contrast toFIG. 17, gasket502includes an opening560in cover550to allow access to a portion562of ceramic core feature, e.g.,312, exposed by the opening. For example, opening560may be sized and positioned to allow access to defect322(FIG. 15). Opening560may be provided to allow material to be removed, e.g., by grinding, but without allowing the material to move outside of opening560, and/or it may be provided to control addition of material, e.g., by way of a blended core material, core fill material and/or ceramic slurry. Opening560may have a size and shape to expose any desired amount and shape of the relevant ceramic core feature, e.g.,312. As shown best inFIG. 20, gasket502may optionally include a dam element564about at least a portion of opening560to prevent material exiting from opening560from entering channel340(FIG. 15), e.g., ceramic slurry used to add ceramic to ceramic core feature312. Dam element564may surround all or just a portion of opening560.

FIG. 21shows a plan view of another embodiment of a gasket602, andFIG. 22a cross-sectional view along line22-22inFIG. 21. Here, gasket602is similar to gasket502, shown inFIGS. 19 and 20.FIG. 20also shows a cross-section along line20-20inFIG. 21. With reference toFIGS. 20 and 21, gasket602includes a cover650configured to cover a portion of a ceramic core feature, e.g.,312, adjacent channel340(FIG. 15), and a channel engaging portion652extending from cover650to self-lock in at least a portion of channel340(FIG. 15). Channel engaging portion652may have any size and shape configured to mate and self-lock in channel340(FIG. 15). While cover650is shown to have a similar shape to that of channel340(FIG. 15), that is not necessary in all instances, e.g., it may cover at least portions of other ceramic core features than just feature312(FIG. 15). Gasket602also includes an opening660in cover650to allow access to a portion662of ceramic core feature, e.g.,312, exposed by the opening. Opening660may be provided to allow material to be removed, e.g., by grinding, but without allowing the material to move outside of opening660, or it may be provided to control addition of ceramic, e.g., by way of a ceramic slurry. Opening660may have a size and shape to expose any desired amount and shape of the relevant ceramic core feature, e.g.,312. As shown best inFIGS. 20 and 21, gasket602may also optionally include a dam element664about at least a portion of opening660to prevent material exiting the opening660from entering channel340(FIG. 15), e.g., ceramic slurry used to add ceramic to ceramic core feature312. Dam element664may surround all or just a portion of opening660. In contrast toFIGS. 19 and 20, gasket602may also include a supplemental cover670that covers another ceramic core feature, e.g.,316(FIG. 15). Supplemental cover670may be integral with cover650, and may include a supplemental channel engaging portion672extending from supplemental cover670to self-lock in at least a portion of channel340(FIG. 15) about ceramic core feature316(FIG. 15). Supplemental cover670prevents material from entering channel340and further prevents damage to adjacent core feature316during various core processing operations such as grinding, blending or filling. In contrast toFIG. 19, supplemental channel engaging portion672may extend only about a portion of supplemental cover670(see open end674inFIGS. 20, 21) to allow a portion of ceramic core feature316to extend therethrough.

In any of the embodiments described heretofore, the gasket may include a flexible material such as but not limited to a thermoplastic polyurethane such as those available from NinjaFlex®. In other embodiments, the gasket may include multiple materials having different rigidities, e.g., materials of different flexibility and/or different hardness, to address positioning and self-locking of the gasket and required stiffness or hardness to protect ceramic core features. For example, in theFIGS. 17, 19 and 21embodiments, covers350,450,550may have a more rigid material, while channel engaging portions352,452,552may include more pliable or flexible material. Additionally, gaskets302,402,502and602may be sized and shape to partially surround core feature312. For example, gaskets302,402,502and602may extend around approximately 50% of core feature312.

While particular embodiments of a ceramic core feature have been illustrated as a boss or a curvilinear cooling circuit geometry, it is understood that ceramic core features may include both types of structure (e.g., with a boss in a channel that is curvilinear), and that the teachings of the disclosure are applicable to a wide variety of alternative core features. That is, the channel can be an elliptical, linear and/or curvilinear in shape.

FIGS. 23-25show another embodiment of a gasket702(FIGS. 23, 24). Gasket702may be used during casting, i.e., with the gasket in-place on an illustrative ceramic core during casting.FIG. 23shows a plan view of gasket702,FIG. 24shows a side view of illustrative ceramic core710with gasket702in-place thereon, andFIG. 25shows a side view of ceramic core710with a broken ceramic core feature774. In this example, ceramic core710may be for forming cooling passage(s) of turbomachine airfoil having a bottom portion776, a serpentine portion778and a top portion780. In addition, between serpentine portion778and each of bottom portion776and top portion780, ceramic core710includes a number of ceramic core features in the form of pins782. It is understood that pins782provide structural integrity to ceramic core710, but also form cooling passages coupling cooling passages of serpentine portion778and each of top and bottom portions776,780(detail not shown for clarity) in the final airfoil. In ceramic core710, a channel740is formed between pins782and portions776,778and780. Here, one broken ceramic core feature774, e.g., broken pin782B (FIG. 25), may be insufficient to cause a user to scrap the ceramic core. (In contrast, where too many pins782are broken, the structural integrity of ceramic core710may be lost, requiring it to be scrapped.) Broken pin782B may also be impossible to repair because, for example, it may be too close to other structure, or so small in dimension that repair is impossible. Pins782may break during formation, rework or during casting, e.g., in terms of casting, pins may break during the firing stages of the investment casting process. Breaking of pins782cannot always be controlled.

As shown best inFIG. 23, gasket702may include a length of material770having at least one protrusion772extending therefrom. Protrusion(s)772is/are configured to self-lock in channel740, e.g., about pins782or other ceramic core features774. Gasket702may have a length made to fit around either two pins782, or the entire region of pins782, e.g., between portions776,778or778,780. Protrusions772may be size to self-lock between pins782, i.e., they have same spacing as between pins782in channel740. Gasket702may also be made to the size of channel740, height-wise as shown inFIG. 24. In one embodiment, heat may be applied to gasket702to melt it around pins782and to ceramic core710. This step may would add extra support to ceramic core710and pins782during casting, but may not be necessary in all cases. Gasket702may remain in place on ceramic core710during casting. While only theFIGS. 23-25embodiment has been described relative to using the gasket in place during casting of the final metal component, it is emphasized that any of the gaskets described herein may be used in this manner. Where the gasket is used in place during casting, the gasket may be formed of a material capable of disintegrating during the casting, e.g., dissolving, evaporating or melting, such that is does not impact the formation of the casting article. Possible materials may include but are not limited to: Ninjaflex material from Ninjatek, Mandheim, Pa., or Irogran (thermoplastic polyurethane) available from Filastruder, Snellville, Ga.

In any of the embodiments described herein, the gaskets may be made using any now known or later developed process such as but not limited to: additive manufacturing, molding in place, stamping, or molding via conventional processes. In any event, the gaskets can be custom made to fit any desired structure where foreign material may lodge in the channel. The gaskets may have a size to create self-locking, tight fit with the channel(s) into which it is placed, i.e., the gasket as a whole may self-lock or just select channel engaging portions thereof. For example, a channel may have a width of approximately 1.27 millimeters (mm) (0.05 inches) to 12.7 mm (0.5 inches), and gasket and/or channel engaging portion (whichever is appropriate) may have a width that is 0.025 mm (0.001 inches) to 0.127 mm (0.005 inches) wider than the channel. In this fashion, an interference fit to self-lock can be created.

Embodiments of the disclosure may also include a method of use of the gaskets. In a first step, a geometrical characteristic of the channel and adjacent ceramic core feature may be determined. This step may include performing any now known or later developed process to identify geometrical characteristics, e.g., manual sketching, obtaining directly from a computer aided design (CAD) model, scanning with a light source such as Blue Light or laser scanning, 3D imaging, coordinated measurement machine (CMM) or other manual or automated measurement, computer aided graphics (CAD) evaluation of ceramic core design, etc. The gasket can then be fabricated to fit and self-lock within the channel, as described herein. More specifically, the gasket can be additive manufactured, molded in place, stamped, or molded via conventional processes. In any event, the gaskets can be custom made to fit any desired structure where foreign material may lodge in the channel, and may take any form within the scope of this disclosure. As noted, the gaskets may have a size to create self-locking, tight fit with the channel(s) into which it is placed, i.e., the gasket as a whole or just channel engaging portions or sub-portions (for example, gasket may have some sections designed for tight fit and other sections with loose fit). The gasket can then be positioned within the channel. For example, as shown inFIG. 10relative to theFIG. 9embodiment, because gasket202is made of flexible material, a force F may be applied to flex it to mate in a self-locking fashion in channel42,44, e.g., about a boss34,36. InFIG. 9, boss34,36is diamond in cross-section. As shown inFIGS. 4 and 5, where boss34,36is elliptical, open center body204is positioned in elliptical channel portion220of channel42,44about a respective elliptical boss34,36. Where provided, first elongate member212extending from a first vertex222of open center body204is positioned in first elongate channel portion224of channel42,44, and second elongate member214extending from second vertex226of elliptical body218is positioned in second elongate channel portion228of channel42,44. A similar process may be carried out for the diamond shaped embodiment ofFIG. 9, or any of the other embodiments described herein. Each of the positioning steps can happen in any order desired, e.g., one elongate member, then elongate body, then the latter elongate member. Each gasket described herein can be self-locked into a respective channel in a similar fashion.

The method may also include performing the core processing operation. This step may include, for example, any process to modify the ceramic core, e.g., rework to add or remove material. In one embodiment, as shown in an example inFIG. 26, the gasket may be removed before proceeding with the rest of the investment casting process. The gasket may be removed using any now known or later developed technique, using a tool like a pick223to start to pull it out of the channel, and then pulling the rest out by hand. In an alternative embodiment, as described relative to theFIGS. 23-25embodiment, but applicable to all embodiments, casting the final metal component may occur with ceramic core10(FIG. 1) with the gasket in place. That is, the gasket is not removed. In this case, the gasket may be formed of a material capable of disintegrating during the casting, e.g., dissolving, evaporating or melting, such that is does not impact the formation of the casting article. The material may include any of the aforementioned materials. Here, the gasket prevents foreign material from lodging in the channel, but also may provide additional support to the ceramic core.

Embodiments of the disclosure provide a system200with a gasket that can be customized to fit where foreign material is not wanted during core processing operations, reducing subsequent damage to the ceramic core compared to the channel without the gasket. Optionally, the gasket can stay in place during casting of the final metal component.

The foregoing drawings show some of the processing associated according to several embodiments of this disclosure. In this regard, each drawing represents a process associated with embodiments of the method described. It should also be noted that in some alternative implementations, the acts noted in the drawings may occur out of the order noted in the figure or, for example, may in fact be executed substantially concurrently or in the reverse order, depending upon the act involved. Also, one of ordinary skill in the art will recognize that other well-known steps of the investment casting process have not been shown, for clarity.