EP3980202B1 - Improved foundry mould for the formation of turbine blade ceramic cores - Google Patents

Improved foundry mould for the formation of turbine blade ceramic cores Download PDF

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Publication number
EP3980202B1
EP3980202B1 EP20740372.6A EP20740372A EP3980202B1 EP 3980202 B1 EP3980202 B1 EP 3980202B1 EP 20740372 A EP20740372 A EP 20740372A EP 3980202 B1 EP3980202 B1 EP 3980202B1
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EP
European Patent Office
Prior art keywords
mold
primary
arm
cavity
volume
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EP20740372.6A
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German (de)
French (fr)
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EP3980202A1 (en
Inventor
Luc ROUGIER
Mirna Bechelany
Virginie JAQUET
Ngadia Taha NIANE
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Safran SA
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Safran SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/06—Permanent moulds for shaped castings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
    • B22C7/06—Core boxes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C13/00—Moulding machines for making moulds or cores of particular shapes
    • B22C13/12—Moulding machines for making moulds or cores of particular shapes for cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/22—Moulds for peculiarly-shaped castings

Definitions

  • This presentation relates to the field of turbomachines, and relates more specifically to techniques for filling foundry core molds for the production of cores with a view to producing turbomachinery components.
  • Ceramic cores are commonly produced by medium or high pressure injection.
  • a paste comprising a ceramic filler incorporated in a polymer binder is injected into a mould, thus making it possible to produce a green body.
  • demoulding the latter is then fired, which makes it possible to carry out debinding and sintering steps, consisting respectively of the elimination of the binder and the consolidation of the core.
  • the wax forming the model of the metal part is injected around the core, the latter thus making it possible to delimit the internal cavity of the part.
  • the documents EP1854869 , FR3037830 And EN 3022811 present known examples of such methods.
  • the most recent core geometries include trailing edges including narrow and very fine teeth, for example up to 0.4 mm.
  • cracks leading to core breakage have been observed almost systematically, especially after core firing. They are often located in the teeth of the trailing edge, or in the immediate vicinity of the latter. It was assumed that one of the phenomena contributing to these cracks/breaks is the separation of the phases (binder and ceramic) during the injection of the paste during the filling of the cavity under pressure.
  • the Interrupted injections have shown the formation of free jets in these teeth, which can prove to be detrimental to the quality of the front junctions and to the homogeneity of the spatial distribution of binder/ceramic, once the material has passed through the teeth.
  • This presentation thus aims to respond at least partially to the problems mentioned above.
  • the ratio between the surface of contact of the primary arm with the body of the mold relative to the volume of the primary arm is equal to plus or minus 20% to the ratio between the surface of contact of the secondary arm with the body of the mold relative to the volume of the secondary arm.
  • the primary arm and the secondary arm are connected to a common injection orifice of the mould.
  • the primary arm and the secondary arm are then typically connected to a supply cavity, the supply cavity being connected to an injection orifice of the mould.
  • the segments comprise a plurality of segments each having a section having a dimension less than or equal to 1 mm 2 .
  • the primary arm and the secondary arm are made in a parting plane of the mould.
  • the primary arm and the secondary arm each have a reduced section portion at their connection with the primary cavity and the secondary cavity respectively.
  • a subsequent step of finishing the ceramic insert is carried out in which the ceramic material corresponding to the secondary arm (or to the volume of the secondary arm) is removed.
  • the figures show schematically a view of a mold 1, which is shown here according to a cutting plane of the mold 1.
  • the mold 1 can have the shape of a rectangular parallelepiped, it being understood that such a representation is not limiting, and that the mold can have any suitable shape, in particular depending on the geometry of the associated core.
  • the mold 1 comprises a body 10 having an internal recess 2 defining an imprint of a foundry core.
  • the figures show this recess 2 via the corresponding foundry core. It would indeed have been hard to read to represent a foundry mould, which is by nature closed.
  • the figures thus representing the foundry core associated with each mold 1, these cores being the volumes complementary to the internal recess 2 of the mold 1 considered.
  • the mold 1 is an injection mold, typically a mold used to inject ceramic pastes.
  • the recess 2 forms an indentation 20 defining the geometry of a core.
  • the cavity 20 comprises a primary volume 20A and a secondary volume 20B connected by a plurality of segments 20C ensuring a passage of fluid between the primary volume 20A and the secondary volume 20B.
  • the primary volume 20A typically defines the internal cavities for a turbine blade, while the secondary volume 20B typically makes it possible to define an internal volume for a bar formed with the turbine blade during the injection of material, the bar being a reservoir of material aimed at avoiding mishaps in the manner of a flyweight.
  • the primary volume 20A can thus be qualified as a functional part of the core, while the secondary volume 20B corresponds to an accessory volume, which will be removed during a machining operation to produce a finished part.
  • the primary volume 20A typically comprises several sub-volumes which can be separated or connected by segments having a reduced cross section with respect to the sub-volumes concerned.
  • the primary volume 20A and the secondary volume 20B have substantially equal internal volumes, typically more or less 15%.
  • Segments 20C are commonly referred to as the "teeth" of the nucleus, and are part of the functional volume of the nucleus. These segments 20C include a plurality of ducts connecting the primary volume 20A and the secondary volume 20B. These ducts each have small dimensions relative to the primary volume 20A and the secondary volume 20B. Each of the segments 20C thus typically has a section of less than 1 mm 2 .
  • the secondary volume 20B is surmounted by a tertiary volume 20D in the extension of the secondary volume 20B, the limit between the secondary volume 20B and the tertiary volume 20D substantially corresponding to the upper limit of the last segment 20C (or tooth) of the core.
  • the tertiary volume 20D generally corresponds to the parts of the core defining the tub and the dome of a blade made using the core.
  • the recess 2 makes it possible to define the geometry of a core typically made of ceramic with a view to producing a moving wheel or a distributor for a high-pressure turbine blade of a turbomachine by lost-wax casting. It is noted that the geometry of the recess 2 is not limiting, and that the present description can be applied to different core geometries.
  • the body 10 of the mold 1 comprises a primary arm 30A and a secondary arm 30B, opening respectively into the primary volume 20A and into the secondary volume 20B.
  • the primary arm 30A and the secondary arm 30B are both connected to a supply cavity 40, which is connected to an injection orifice 50 via an injection duct 45, so as to allow the cavity of the mold 1 to be filled with material.
  • the primary arm 30A here fulfills a function for the material supply of the mold cavity 1 and also forms a functional part of the ceramic insert thus produced by defining a cavity in the cooling device of a blade formed using the ceramic insert.
  • the secondary arm 30B which is not a functional part of the core is removed after production of the ceramic insert and before positioning the ceramic insert in a wax injection mold, while the primary arm 30A is retained.
  • the distributor 40 is an intermediate volume, connecting the primary arm 30A and the secondary arm 30B to the injection conduit 45.
  • the supply cavity 40 is configured so as to distribute a suspension or a fluid which is injected via the injection conduit between the primary arm 30A and the secondary arm 30B.
  • the injection duct 45 is connected to the injection orifice 50, the latter being adapted to be connected to a supply source of a suspension or of a pressurized fluid.
  • the primary arm 30A makes it possible to fill the primary volume 20A with material, for example a ceramic suspension.
  • the secondary arm 30B makes it possible to fill the secondary volume 20B with material, for example a ceramic suspension, by preventing the latter from filling the impression exclusively by crossing the teeth, and by reducing the cooling of the injected material.
  • material for example a ceramic suspension
  • the primary arm 30A and the secondary arm 30B typically extend in a joint plane of the mold 1.
  • the injection duct 45 and the supply cavity 40 also typically extend in a joint plane of the mold 1, which facilitates the opening of the mold 1 after injection of material.
  • the secondary arm 30B is advantageously dimensioned so as to ensure a distribution of material between the primary volume 20A and the secondary volume 20B of the cavity 20. Indeed, insofar as the primary arm 30A is a functional part of the core, it cannot be dimensioned freely.
  • the primary volume 20A has a volume V1
  • the secondary volume has a volume V2
  • the primary arm 30A has a volume V3
  • the secondary arm 30B has a volume V4
  • these volumes are typically dimensioned so that the ratio V1/V2 is equal to the ratio V3/V4, typically to within 20%, or for example to within 15%, or for example substantially to within 15%, or for example to within 10%, or for example to 5% close.
  • the volumes V1 and V2 are equal or substantially equal, then the volumes V3 and V4 are typically equal or substantially equal.
  • the secondary arm 30B is also dimensioned so that the primary arm 30A and the secondary arm 30B have equal or substantially equal ratios between their contact surface with the body 10 of the mold 1 and their respective volumes.
  • a contact surface S3 and S4 respectively is defined which corresponds to the peripheral surface of each of the supply ducts.
  • This contact surface corresponds to the surface of the body 10 of the mold 1 which will be in contact with the material injected into the primary 30A or secondary 30B arm.
  • the secondary arm 30B is typically dimensioned so that the S3/V3 and S4/V4 ratios are equal or substantially equal, or typically equal to within 20%.
  • this ratio determines in particular the heat exchanges occurring between the material injected into the mold 1 and the body 10 of the mold 1.
  • keeping an identical or similar S/V ratio allows the injected material to reach the primary volume 20A and the secondary volume 20B of the cavity 20 in substantially identical states, which improves the junctions of material within the cavity 20.
  • the S/V ratio then depends only on the radius of the cylindrical section of revolution, which makes it possible to simplify the dimensioning of the primary arm 30A and of the secondary arm 30B.
  • the primary arm 30A typically has a reduced section portion at its junction with the primary volume 20A.
  • the secondary arm 30B typically has a portion of reduced section at its junction with the secondary volume 20B.
  • a test of the mold thus dimensioned is typically carried out by digital simulation, in particular in order to verify the proper balancing of the volumes of the different zones during the filling of the mold before making the mold.
  • THE figures 2, 3 And 4 illustrate different stages of filling such a mold for the production of a ceramic foundry insert for the production of a hollow turbine blade.
  • FIG. 2 represents the entry of the material into the primary volume 20A and into the secondary volume 20B of the cavity 20, which is thus filled along two distinct fronts.
  • FIG. 3 And 4 illustrate the junction between the two fronts of material M, as the cavity 20 of the mold 1 is filled.
  • junction between the two fronts of material takes place quickly after the entry of the material into the primary volume 20A and into the secondary volume 20B, typically at the level of the segments 20C.
  • the junction is thus carried out while the material has a relatively high temperature, which ensures good miscibility and avoids or limits the formation of discontinuities or other defects due to rapid changes in viscosity within the material.
  • the core thus produced then comprises a primary body, a secondary body and a tertiary body corresponding respectively to the primary volume 20A, to the secondary volume 20B and to the tertiary volume 20D, the primary body and the secondary body being connected by teeth corresponding to the volume of the segments 20C.
  • the primary arm and the secondary arm respectively define a primary leg and a secondary leg extending from the primary body and the secondary body respectively, the secondary leg extending from a distal end of the secondary body, opposite a proximal end of the secondary body from which the tertiary body extends.
  • the primary branch and the secondary branch meet at a tertiary branch corresponding to the volume defined by the supply cavity 40, and extending by a chimney corresponding to the volume of the injection duct 45.
  • the part of the insert corresponding to the volume of the secondary arm 30B is removed, for example by machining.
  • the mold structure as proposed has several advantages over a conventional mold for producing such a core which only comprises a single feed path.
  • the proposed mold makes it possible to limit the risks of mishap as well as the formation of segregated zones and free jets in the part, and also the risks of poor material joining.
  • the proposed mold makes it possible to limit the differential shrinkage leading to the deformation and rupture of the core.
  • the proposed mold makes it possible to limit the residual stresses as well as the pressure observed within the injected material, which thus makes it possible to obtain a foundry core having better properties, and which is therefore less likely to break during its use for the formation of a turbomachine turbine blade.
  • the pressure reduction during the injection allows in particular to reduce the wear of mold 1.
  • the reduction in shear rates makes it possible to reduce the risks of phase separation.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)

Description

Domaine TechniqueTechnical area

Le présent exposé concerne le domaine des turbomachines, et concerne plus précisément les techniques de remplissage de moule de noyaux de fonderie pour la réalisation de noyaux en vue de la réalisation de composants de turbomachines.This presentation relates to the field of turbomachines, and relates more specifically to techniques for filling foundry core molds for the production of cores with a view to producing turbomachinery components.

Technique antérieurePrior technique

La réalisation de noyaux céramique pour la formation de composants de turbomachine, et plus précisément pour la formation d'aubes de turbine haute pression et de distributeurs haute pression de turbomachine pose une problématique liée notamment à la géométrie spécifique de telles pièces.The production of ceramic cores for the formation of turbomachine components, and more specifically for the formation of high-pressure turbine blades and high-pressure turbomachine distributors poses a problem related in particular to the specific geometry of such parts.

Les noyaux en céramique sont communément produits par injection en moyenne ou haute pression. Une pâte comprenant une charge céramique incorporée dans un liant polymère est injectée dans un moule, permettant ainsi de produire un corps cru. Après démoulage, ce dernier est ensuite cuit, ce qui permet de réaliser des étapes de déliantage et frittage, consistant respectivement en l'élimination du liant et la consolidation du noyau. À l'issue de ces étapes, la cire formant le modèle de la pièce métallique est injectée autour du noyau, ce dernier permettant ainsi de délimiter la cavité interne à la pièce. Les document EP1854869 , FR3037830 et FR 3022811 présentent des exemples connus de tels procédés.Ceramic cores are commonly produced by medium or high pressure injection. A paste comprising a ceramic filler incorporated in a polymer binder is injected into a mould, thus making it possible to produce a green body. After demoulding, the latter is then fired, which makes it possible to carry out debinding and sintering steps, consisting respectively of the elimination of the binder and the consolidation of the core. At the end of these steps, the wax forming the model of the metal part is injected around the core, the latter thus making it possible to delimit the internal cavity of the part. The documents EP1854869 , FR3037830 And EN 3022811 present known examples of such methods.

Les géométries de noyaux les plus récentes comprennent des bords de fuite incluant des dents étroites et très fines, par exemple jusqu'à 0,4 mm. Sur ce type de géométries, des fissures menant à la casse des noyaux ont été observées d'une manière quasi-systématique, notamment après la cuisson du noyau. Elles sont souvent localisées dans les dents du bord de fuite, ou à proximité immédiate de ces dernières. Il a été supposé que l'un des phénomènes contribuant à ces fissurations/casses est la séparation des phases (liant et céramique) au cours de l'injection de la pâte durant le remplissage de la cavité sous pression. Des injections interrompues ont montré la formation de jets libres dans ces dents, ce qui peut s'avérer être préjudiciable à la qualité des jonctions de fronts et à l'homogénéité de la distribution spatiale de liant/céramique, une fois que la matière a traversé les dents. Il a également été supposé que cela soit lié à la géométrie locale, qui est caractérisée par des passages où la surface d'échange avec le moule rapportée au volume augmente rapidement, ce qui entraîne un refroidissement rapide de la pâte, et donc, potentiellement, la formation de jonctions fragiles, ainsi que par une forme pouvant localement favoriser les écoulements convergents, ces derniers venant augmenter le risque d'une augmentation mal contrôlée de la vitesse d'écoulement de la pâte. D'autre part, le refroidissement local, potentiellement rapide, peut être atténué en augmentant la vitesse de passage de la pâte, mais ceci vient alors accentuer le problème de ségrégation.The most recent core geometries include trailing edges including narrow and very fine teeth, for example up to 0.4 mm. On this type of geometries, cracks leading to core breakage have been observed almost systematically, especially after core firing. They are often located in the teeth of the trailing edge, or in the immediate vicinity of the latter. It was assumed that one of the phenomena contributing to these cracks/breaks is the separation of the phases (binder and ceramic) during the injection of the paste during the filling of the cavity under pressure. Of the Interrupted injections have shown the formation of free jets in these teeth, which can prove to be detrimental to the quality of the front junctions and to the homogeneity of the spatial distribution of binder/ceramic, once the material has passed through the teeth. It has also been assumed that this is linked to the local geometry, which is characterized by passages where the exchange surface with the mold in relation to the volume increases rapidly, which leads to rapid cooling of the dough, and therefore, potentially, the formation of fragile junctions, as well as by a shape that can locally favor convergent flows, the latter increasing the risk of a poorly controlled increase in the flow rate of the dough. On the other hand, the potentially rapid local cooling can be reduced by increasing the speed of passage of the paste, but this then accentuates the problem of segregation.

Exposé de l'inventionDisclosure of Invention

Le présent exposé vise ainsi à répondre au moins partiellement aux problématiques mentionnées précédemment.This presentation thus aims to respond at least partially to the problems mentioned above.

Le présent exposé concerne ainsi un moule pour la réalisation d'un noyau céramique par injection d'une composition céramique,

  • le moule comprenant un corps dans lequel est formée une empreinte de noyau de fonderie, ladite empreinte comprenant une cavité primaire et une cavité secondaire reliées par une pluralité de segments permettant un passage de fluide entre la cavité primaire et la cavité secondaire, la cavité primaire définissant des évidements d'une aube de turbomachine,
  • ledit moule étant caractérisé en ce qu'il comprend un bras primaire configuré de manière à permettre une injection de composition céramique dans la cavité primaire, et un bras secondaire configuré de manière à permettre une injection de composition céramique dans la cavité secondaire, et en ce que le rapport entre le volume de la cavité primaire et le volume de la cavité secondaire est égal à plus ou moins 15% au rapport entre le volume du bras primaire et le volume du bras secondaire.
The present presentation thus relates to a mold for producing a ceramic core by injection of a ceramic composition,
  • the mold comprising a body in which is formed a foundry core cavity, said cavity comprising a primary cavity and a secondary cavity connected by a plurality of segments allowing a passage of fluid between the primary cavity and the secondary cavity, the primary cavity defining recesses of a turbomachine blade,
  • said mold being characterized in that it comprises a primary arm configured so as to allow injection of ceramic composition into the primary cavity, and a secondary arm configured so as to allow injection of ceramic composition into the secondary cavity, and in that the ratio between the volume of the primary cavity and the volume of the secondary cavity is equal to plus or minus 15% of the ratio between the volume of the primary arm and the volume of the secondary arm.

Selon un exemple, le rapport entre la surface de contact du bras primaire avec le corps du moule par rapport au volume du bras primaire est égal à plus ou moins 20% au rapport entre la surface de contact du bras secondaire avec le corps du moule par rapport au volume du bras secondaire.According to one example, the ratio between the surface of contact of the primary arm with the body of the mold relative to the volume of the primary arm is equal to plus or minus 20% to the ratio between the surface of contact of the secondary arm with the body of the mold relative to the volume of the secondary arm.

Selon un exemple, le bras primaire et le bras secondaire sont reliés à un orifice d'injection commun du moule.According to one example, the primary arm and the secondary arm are connected to a common injection orifice of the mould.

Le bras primaire et le bras secondaire sont alors typiquement reliés à une cavité d'alimentation, la cavité d'alimentation étant reliée à un orifice d'injection du moule.The primary arm and the secondary arm are then typically connected to a supply cavity, the supply cavity being connected to an injection orifice of the mould.

Selon un exemple, les segments comprennent une pluralité de segments présentant chacun une section ayant une dimension inférieure ou égale à 1mm2.According to one example, the segments comprise a plurality of segments each having a section having a dimension less than or equal to 1 mm 2 .

Selon un exemple, le bras primaire et le bras secondaire sont réalisés dans un plan de joint du moule.According to one example, the primary arm and the secondary arm are made in a parting plane of the mould.

Selon un exemple, le bras primaire et le bras secondaire présentent chacun une portion de section réduite au niveau de leur liaison avec la cavité primaire et la cavité secondaire respectivement.According to one example, the primary arm and the secondary arm each have a reduced section portion at their connection with the primary cavity and the secondary cavity respectively.

Le présent exposé concerne également un procédé de réalisation d'un insert céramique de fonderie pour la réalisation d'une aube de turbine, dans lequel

  • on fournit un moule tel que défini précédemment,
  • on injecte une composition céramique dans le moule de manière à remplir la cavité primaire et la cavité secondaire via le bras primaire et le bras secondaire respectivement.
This presentation also relates to a process for producing a ceramic foundry insert for producing a turbine blade, in which
  • a mold is provided as defined above,
  • a ceramic composition is injected into the mold so as to fill the primary cavity and the secondary cavity via the primary arm and the secondary arm respectively.

Selon un exemple, on réalise une étape ultérieure de finition de l'insert céramique dans laquelle le matériau céramique correspondant au bras secondaire (ou au volume du bras secondaire) est supprimé.According to one example, a subsequent step of finishing the ceramic insert is carried out in which the ceramic material corresponding to the secondary arm (or to the volume of the secondary arm) is removed.

Le présent exposé concerne également un noyau céramique comprenant

  • un corps primaire et un corps secondaire reliés par une pluralité de dents,
  • un corps tertiaire s'étendant depuis une extrémité proximale du corps secondaire,
  • une branche primaire s'étendant depuis le volume primaire,
  • une branche secondaire s'étendant depuis une extrémité distale du corps secondaire, opposée à l'extrémité proximale,
  • une branche tertiaire, reliée à la branche primaire et à la branche secondaire, et
  • une cheminée, s'étendant dans le prolongement de la branche tertiaire,
dans lequel le rapport entre le volume du corps primaire et le volume du corps secondaire est égal à 15% près au rapport entre le volume de la branche primaire et le volume de la branche secondaire.This disclosure also relates to a ceramic core comprising
  • a primary body and a secondary body connected by a plurality of teeth,
  • a tertiary body extending from a proximal end of the secondary body,
  • a primary branch extending from the primary volume,
  • a secondary branch extending from a distal end of the secondary body, opposite the proximal end,
  • a tertiary branch, connected to the primary branch and to the secondary branch, and
  • a chimney, extending in the extension of the tertiary branch,
in which the ratio between the volume of the primary body and the volume of the secondary body is equal to within 15% of the ratio between the volume of the primary branch and the volume of the secondary branch.

Brève description des dessinsBrief description of the drawings

L'invention et ses avantages seront mieux compris à la lecture de la description détaillée faite ci-après de différents modes de réalisation de l'invention donnés à titre d'exemples non limitatifs.

  • [Fig. 1] La figure 1 présente un exemple de noyau de fonderie réalisé au moyen d'un moule et d'un procédé selon un aspect de l'invention.
  • [Fig. 2] La figure 2 illustre une étape de remplissage du moule selon un aspect de l'invention.
  • [Fig. 3] La figure 3 illustre une étape de remplissage du moule selon un aspect de l'invention.
  • [Fig. 4] La figure 4 illustre une étape de remplissage du moule selon un aspect de l'invention.
The invention and its advantages will be better understood on reading the detailed description given below of various embodiments of the invention given by way of non-limiting examples.
  • [ Fig. 1 ] There figure 1 presents an example of a foundry core produced using a mold and a method according to one aspect of the invention.
  • [ Fig. 2 ] There figure 2 illustrates a mold filling step according to one aspect of the invention.
  • [ Fig. 3 ] There picture 3 illustrates a mold filling step according to one aspect of the invention.
  • [ Fig. 4 ] There figure 4 illustrates a mold filling step according to one aspect of the invention.

Sur l'ensemble des figures, les éléments en commun sont repérés par des références numériques identiques.In all of the figures, the elements in common are identified by identical reference numerals.

Description des modes de réalisationDescription of embodiments

On représente schématiquement sur les figures une vue d'un moule 1, qui est ici représenté selon un plan de coupe du moule 1. Le moule 1 peut avoir une forme de parallélépipède rectangle, étant entendu qu'une telle représentation n'est pas limitative, et que le moule peut présenter toute forme adaptée notamment en fonction de la géométrie du noyau associé.The figures show schematically a view of a mold 1, which is shown here according to a cutting plane of the mold 1. The mold 1 can have the shape of a rectangular parallelepiped, it being understood that such a representation is not limiting, and that the mold can have any suitable shape, in particular depending on the geometry of the associated core.

Le moule 1 comprend un corps 10 présentant un évidement 2 interne définissant une empreinte d'un noyau de fonderie. Les figures représentent cet évidement 2 via le noyau de fonderie correspondant. Il aurait en effet été peu lisible de représenter un moule de fonderie, qui est par nature fermé. Les figures représentant ainsi le noyau de fonderie associé à chaque moule 1, ces noyaux étant les volumes complémentaires à l'évidement 2 interne du moule 1 considéré. Le moule 1 est un moule d'injection, typiquement un moule utilisé pour injecter des pâtes céramiques.The mold 1 comprises a body 10 having an internal recess 2 defining an imprint of a foundry core. The figures show this recess 2 via the corresponding foundry core. It would indeed have been hard to read to represent a foundry mould, which is by nature closed. The figures thus representing the foundry core associated with each mold 1, these cores being the volumes complementary to the internal recess 2 of the mold 1 considered. The mold 1 is an injection mold, typically a mold used to inject ceramic pastes.

Dans l'exemple représenté sur la figure 1, l'évidement 2 forme une empreinte 20 définissant la géométrie d'un noyau. Dans l'exemple illustré sur les figures, l'empreinte 20 comprend un volume primaire 20A et un volume secondaire 20B reliés par une pluralité de segments 20C assurant un passage de fluide entre le volume primaire 20A et le volume secondaire 20B.In the example shown in the figure 1 , the recess 2 forms an indentation 20 defining the geometry of a core. In the example illustrated in the figures, the cavity 20 comprises a primary volume 20A and a secondary volume 20B connected by a plurality of segments 20C ensuring a passage of fluid between the primary volume 20A and the secondary volume 20B.

Le volume primaire 20A définit typiquement les cavités internes pour une aube de turbine, tandis que le volume secondaire 20B permet typiquement de définir un volume interne à une barrette formée avec l'aube de turbine lors de l'injection de matière, la barrette étant un réservoir de matière visant à éviter les malvenues à la manière d'une masselotte. Le volume primaire 20A peut ainsi être qualifié de partie fonctionnelle du noyau, tandis que le volume secondaire 20B correspond à un volume accessoire, qui sera retiré lors d'une opération d'usinage pour réaliser une pièce finie.The primary volume 20A typically defines the internal cavities for a turbine blade, while the secondary volume 20B typically makes it possible to define an internal volume for a bar formed with the turbine blade during the injection of material, the bar being a reservoir of material aimed at avoiding mishaps in the manner of a flyweight. The primary volume 20A can thus be qualified as a functional part of the core, while the secondary volume 20B corresponds to an accessory volume, which will be removed during a machining operation to produce a finished part.

Le volume primaire 20A comprend typiquement plusieurs sous-volumes pouvant être disjoints ou reliés par des segments ayant une section réduite par rapport aux sous-volumes concernés.The primary volume 20A typically comprises several sub-volumes which can be separated or connected by segments having a reduced cross section with respect to the sub-volumes concerned.

Le volume primaire 20A et le volume secondaire 20B présentent des volumes internes sensiblement égaux, typiquement à plus ou moins 15%.The primary volume 20A and the secondary volume 20B have substantially equal internal volumes, typically more or less 15%.

Les segments 20C sont communément désignés comme étant les « dents » du noyau, et font partie du volume fonctionnel du noyau. Ces segments 20C comprennent une pluralité de conduits reliant le volume primaire 20A et le volume secondaire 20B. Ces conduits présentent chacun des dimensions faibles par rapport au volume primaire 20A et au volume secondaire 20B. Chacun des segments 20C présente ainsi typiquement une section inférieure à 1mm2.Segments 20C are commonly referred to as the "teeth" of the nucleus, and are part of the functional volume of the nucleus. These segments 20C include a plurality of ducts connecting the primary volume 20A and the secondary volume 20B. These ducts each have small dimensions relative to the primary volume 20A and the secondary volume 20B. Each of the segments 20C thus typically has a section of less than 1 mm 2 .

Le volume secondaire 20B est surmonté d'un volume tertiaire 20D dans le prolongement du volume secondaire 20B, la limite entre le volume secondaire 20B et le volume tertiaire 20D correspondant sensiblement à la limite supérieure du dernier segment 20C (ou dent) du noyau. Le volume tertiaire 20D correspond généralement les parties du noyau définissant la baignoire et le dôme d'une aube réalisée à l'aide du noyau.The secondary volume 20B is surmounted by a tertiary volume 20D in the extension of the secondary volume 20B, the limit between the secondary volume 20B and the tertiary volume 20D substantially corresponding to the upper limit of the last segment 20C (or tooth) of the core. The tertiary volume 20D generally corresponds to the parts of the core defining the tub and the dome of a blade made using the core.

Dans l'exemple représenté, l'évidement 2 permet de définir la géométrie d'un noyau typiquement réalisé en céramique en vue de la réalisation d'une roue mobile ou d'un distributeur d'une aube de turbine haute pression d'une turbomachine par voie de fonderie à cire perdue. On note que la géométrie de l'évidement 2 n'est pas limitative, et que le présent exposé peut être appliqué à différentes géométries de noyaux.In the example shown, the recess 2 makes it possible to define the geometry of a core typically made of ceramic with a view to producing a moving wheel or a distributor for a high-pressure turbine blade of a turbomachine by lost-wax casting. It is noted that the geometry of the recess 2 is not limiting, and that the present description can be applied to different core geometries.

Le corps 10 du moule 1 comprend un bras primaire 30A et un bras secondaire 30B, débouchant respectivement dans le volume primaire 20A et dans le volume secondaire 20B.The body 10 of the mold 1 comprises a primary arm 30A and a secondary arm 30B, opening respectively into the primary volume 20A and into the secondary volume 20B.

Dans l'exemple illustré, le bras primaire 30A et le bras secondaire 30B sont tous deux reliés à une cavité d'alimentation 40, qui est reliée à un orifice d'injection 50 via un conduit d'injection 45, de manière à permettre de remplir l'empreinte du moule 1 de matière. On note que contrairement au bras secondaire 30B qui ne remplit qu'une fonction de canal d'alimentation en matière, le bras primaire 30A remplit ici une fonction pour l'alimentation en matière de l'empreinte du moule 1 et forme également une partie fonctionnelle de l'insert céramique ainsi réalisé en définissant une cavité dans le dispositif de refroidissement d'une aube formée à l'aide de l'insert céramique. Ainsi, le bras secondaire 30B qui n'est pas une partie fonctionnelle du noyau est supprimée après réalisation de l'insert céramique et avant positionnement de l'insert céramique dans un moule d'injection cire, tandis que le bras primaire 30A est conservé.In the example illustrated, the primary arm 30A and the secondary arm 30B are both connected to a supply cavity 40, which is connected to an injection orifice 50 via an injection duct 45, so as to allow the cavity of the mold 1 to be filled with material. It is noted that unlike the secondary arm 30B which only fulfills a material supply channel function, the primary arm 30A here fulfills a function for the material supply of the mold cavity 1 and also forms a functional part of the ceramic insert thus produced by defining a cavity in the cooling device of a blade formed using the ceramic insert. Thus, the secondary arm 30B which is not a functional part of the core is removed after production of the ceramic insert and before positioning the ceramic insert in a wax injection mold, while the primary arm 30A is retained.

Le distributeur 40 est un volume intermédiaire, reliant le bras primaire 30A et le bras secondaire 30B au conduit d'injection 45. La cavité d'alimentation 40 est configurée de manière à répartir une suspension ou un fluide qui est injecté via le conduit d'injection entre le bras primaire 30A et le bras secondaire 30B.The distributor 40 is an intermediate volume, connecting the primary arm 30A and the secondary arm 30B to the injection conduit 45. The supply cavity 40 is configured so as to distribute a suspension or a fluid which is injected via the injection conduit between the primary arm 30A and the secondary arm 30B.

Le conduit d'injection 45 est relié à l'orifice d'injection 50, ce dernier étant adapté pour être relié à une source d'alimentation d'une suspension ou d'un fluide sous pression.The injection duct 45 is connected to the injection orifice 50, the latter being adapted to be connected to a supply source of a suspension or of a pressurized fluid.

Le bras primaire 30A permet de remplir le volume primaire 20A de matière, par exemple une suspension céramique.The primary arm 30A makes it possible to fill the primary volume 20A with material, for example a ceramic suspension.

Le bras secondaire 30B permet de remplir le volume secondaire 20B de matière, par exemple une suspension céramique, en évitant que cette dernière ne remplisse l'empreinte exclusivement en traversant les dents, et en réduisant le refroidissement de la matière injectée.The secondary arm 30B makes it possible to fill the secondary volume 20B with material, for example a ceramic suspension, by preventing the latter from filling the impression exclusively by crossing the teeth, and by reducing the cooling of the injected material.

Le bras primaire 30A et le bras secondaire 30B s'étendent typiquement dans un plan de joint du moule 1. Le conduit d'injection 45 et la cavité d'alimentation 40 s'étendent également typiquement dans un plan de joint du moule 1, ce qui permet de faciliter l'ouverture du moule 1 après injection de matière.The primary arm 30A and the secondary arm 30B typically extend in a joint plane of the mold 1. The injection duct 45 and the supply cavity 40 also typically extend in a joint plane of the mold 1, which facilitates the opening of the mold 1 after injection of material.

Afin d'assurer un bon remplissage de l'empreinte 20, on dimensionne avantageusement le bras secondaire 30B de manière à assurer une distribution de matière entre le volume primaire 20A et le volume secondaire 20B de l'empreinte 20. En effet, dans la mesure où le bras primaire 30A est une partie fonctionnelle du noyau, elle ne peut pas être dimensionnée librement.In order to ensure good filling of the cavity 20, the secondary arm 30B is advantageously dimensioned so as to ensure a distribution of material between the primary volume 20A and the secondary volume 20B of the cavity 20. Indeed, insofar as the primary arm 30A is a functional part of the core, it cannot be dimensioned freely.

Ainsi, en considérant que le volume primaire 20A présente un volume V1, le volume secondaire présente un volume V2, le bras primaire 30A présente un volume V3 et le bras secondaire 30B présente un volume V4, ces volumes sont typiquement dimensionnés de sorte que le ratio V1/V2 soit égal au ratio V3/V4, typiquement à 20% près, ou par exemple à 15% près, ou par exemple sensiblement à 15% près, ou par exemple à 10% près, ou par exemple à 5% près.Thus, considering that the primary volume 20A has a volume V1, the secondary volume has a volume V2, the primary arm 30A has a volume V3 and the secondary arm 30B has a volume V4, these volumes are typically dimensioned so that the ratio V1/V2 is equal to the ratio V3/V4, typically to within 20%, or for example to within 15%, or for example substantially to within 15%, or for example to within 10%, or for example to 5% close.

Dans le cas où les volumes V1 et V2 sont égaux ou sensiblement égaux, alors les volumes V3 et V4 sont typiquement égaux ou sensiblement égaux.If the volumes V1 and V2 are equal or substantially equal, then the volumes V3 and V4 are typically equal or substantially equal.

De manière avantageuse on dimensionne également le bras secondaire 30B de manière à ce que le bras primaire 30A et le bras secondaire 30B présentent des rapports égaux ou sensiblement égaux entre leur surface de contact avec le corps 10 du moule 1 et leurs volumes respectifs.Advantageously, the secondary arm 30B is also dimensioned so that the primary arm 30A and the secondary arm 30B have equal or substantially equal ratios between their contact surface with the body 10 of the mold 1 and their respective volumes.

Plus précisément, on définit pour le bras primaire 30A et pour le bras secondaire 30B une surface de contact respectivement S3 et S4 qui correspond à la surface périphérique de chacun des conduits d'alimentation. Cette surface de contact correspond à la surface du corps 10 du moule 1 qui sera au contact de la matière injectée dans le bras primaire 30A ou secondaire 30B.More precisely, for the primary arm 30A and for the secondary arm 30B, a contact surface S3 and S4 respectively is defined which corresponds to the peripheral surface of each of the supply ducts. This contact surface corresponds to the surface of the body 10 of the mold 1 which will be in contact with the material injected into the primary 30A or secondary 30B arm.

Ainsi, on dimensionne typiquement le bras secondaire 30B de sorte que les rapports S3/V3 et S4/V4 soient égaux ou sensiblement égaux, ou typiquement égaux à 20% près.Thus, the secondary arm 30B is typically dimensioned so that the S3/V3 and S4/V4 ratios are equal or substantially equal, or typically equal to within 20%.

En effet, ce rapport détermine notamment les échanges thermiques se produisant entre la matière injectée dans le moule 1 et le corps 10 du moule 1. Ainsi, conserver un rapport S/V identique ou similaire permet que la matière injectée atteigne le volume primaire 20A et le volume secondaire 20B de l'empreinte 20 dans des états sensiblement identiques, ce qui améliore les jonctions de matière au sein de l'empreinte 20.Indeed, this ratio determines in particular the heat exchanges occurring between the material injected into the mold 1 and the body 10 of the mold 1. Thus, keeping an identical or similar S/V ratio allows the injected material to reach the primary volume 20A and the secondary volume 20B of the cavity 20 in substantially identical states, which improves the junctions of material within the cavity 20.

Dans le cas où le bras primaire 30A et le bras secondaire 30B sont cylindriques de révolution, le rapport S/V dépend alors uniquement du rayon de la section cylindrique de révolution, ce qui permet de simplifier le dimensionnement du bras primaire 30A et du bras secondaire 30B.In the case where the primary arm 30A and the secondary arm 30B are cylindrical of revolution, the S/V ratio then depends only on the radius of the cylindrical section of revolution, which makes it possible to simplify the dimensioning of the primary arm 30A and of the secondary arm 30B.

Le bras primaire 30A présente typiquement une portion de section réduite au niveau de sa jonction avec le volume primaire 20A. De même, le bras secondaire 30B présente typiquement une portion de section réduite au niveau de sa jonction avec le volume secondaire 20B.The primary arm 30A typically has a reduced section portion at its junction with the primary volume 20A. Similarly, the secondary arm 30B typically has a portion of reduced section at its junction with the secondary volume 20B.

Former ainsi un rétrécissement du secondaire à son extrémité permet de concentrer les contraintes thermomécaniques dans ce dernier, ce qui peut faciliter la séparation du secondaire par rapport à la pièce injectée, et donc la finition du noyau, tout en réduisant les risques d'endommagement de la partie fonctionnelle du noyau. Toutefois, ce rétrécissement est typiquement assez peu marqué afin d'éviter la ségrégation et/ou la formation de jets au niveau de la jonction entre le volume secondaire 20B et le bras secondaire 30B.Forming a narrowing of the secondary in this way at its end makes it possible to concentrate the thermomechanical stresses in the latter, which can facilitate the separation of the secondary from the injected part, and therefore the finishing of the core, while reducing the risk of damage to the functional part of the core. However, this narrowing is typically not very marked in order to avoid segregation and/or the formation of jets at the junction between the secondary volume 20B and the secondary arm 30B.

Une fois le bras secondaire 30B dimensionné, on réalise typiquement un test du moule ainsi dimensionné par simulation numérique, notamment afin de vérifier le bon équilibrage des volumes des différentes zones lors du remplissage du moule avant de réaliser le moule.Once the secondary arm 30B has been dimensioned, a test of the mold thus dimensioned is typically carried out by digital simulation, in particular in order to verify the proper balancing of the volumes of the different zones during the filling of the mold before making the mold.

Les figures 2, 3 et 4 illustrent différentes étapes du remplissage d'un tel moule pour la réalisation d'un insert céramique de fonderie en vue de la réalisation d'une aube creuse de turbine.THE figures 2, 3 And 4 illustrate different stages of filling such a mold for the production of a ceramic foundry insert for the production of a hollow turbine blade.

La figure 2 représente l'entrée de la matière dans le volume primaire 20A et dans le volume secondaire 20B de l'empreinte 20, qui est ainsi remplie selon deux fronts distincts.There figure 2 represents the entry of the material into the primary volume 20A and into the secondary volume 20B of the cavity 20, which is thus filled along two distinct fronts.

Les figures 3 et 4 illustrent la jonction entre les deux fronts de matière M, au fur et à mesure du remplissage de l'empreinte 20 du moule 1.THE figure 3 And 4 illustrate the junction between the two fronts of material M, as the cavity 20 of the mold 1 is filled.

On voit sur ces figures que les différentes régions d'épaisseur moindre, notamment les segments 20C et le cas échéant des portions d'épaisseur moindre au sein du volume primaire 20A sont remplies de matière directement après que la matière pénètre dans le volume primaire 20A ou dans le volume secondaire 20B. Une telle configuration réduit fortement ou annule les risques de malvenue et de ségrégation et/ou formation de jets libres, notamment en évitant que la matière en provenance d'un même bras doive passer par deux restrictions du moule 1.It can be seen in these figures that the various regions of less thickness, in particular the segments 20C and, where appropriate, portions of less thickness within the primary volume 20A are filled with material directly after the material enters the primary volume 20A or the secondary volume 20B. Such a configuration greatly reduces or eliminates the risks of mishap and of segregation and/or formation of free jets, in particular by preventing the material coming from the same arm from having to pass through two restrictions of the mold 1.

De plus, on voit que la jonction entre les deux fronts de matière se réalise rapidement après l'entrée de la matière dans le volume primaire 20A et dans le volume secondaire 20B, typiquement au niveau des segments 20C.Moreover, it can be seen that the junction between the two fronts of material takes place quickly after the entry of the material into the primary volume 20A and into the secondary volume 20B, typically at the level of the segments 20C.

La jonction se réalise ainsi alors que la matière présente une température relativement élevée ce qui assure une bonne miscibilité et évite ou limite la formation de discontinuités ou autres défauts dus à des variations rapides de viscosité au sein de la matière.The junction is thus carried out while the material has a relatively high temperature, which ensures good miscibility and avoids or limits the formation of discontinuities or other defects due to rapid changes in viscosity within the material.

Le noyau ainsi réalisé comprend alors un corps primaire, un corps secondaire et un corps tertiaire correspondant respectivement au volume primaire 20A, au volume secondaire 20B et au volume tertiaire 20D, le corps primaire et le corps secondaire étant reliés par des dents correspondant au volume des segments 20C. Le bras primaire et le bras secondaire définissent respectivement une branche primaire et une branche secondaire s'étendant depuis le corps primaire et le corps secondaire respectivement, la branche secondaire s'étendant depuis une extrémité distale du corps secondaire, opposée à une extrémité proximale du corps secondaire depuis laquelle s'étend le corps tertiaire. La branche primaire et la branche secondaire se rejoignent au niveau d'une branche tertiaire correspondant au volume défini par la cavité d'alimentation 40, et se prolongeant par une cheminée correspondant au volume du conduit d'injection 45.The core thus produced then comprises a primary body, a secondary body and a tertiary body corresponding respectively to the primary volume 20A, to the secondary volume 20B and to the tertiary volume 20D, the primary body and the secondary body being connected by teeth corresponding to the volume of the segments 20C. The primary arm and the secondary arm respectively define a primary leg and a secondary leg extending from the primary body and the secondary body respectively, the secondary leg extending from a distal end of the secondary body, opposite a proximal end of the secondary body from which the tertiary body extends. The primary branch and the secondary branch meet at a tertiary branch corresponding to the volume defined by the supply cavity 40, and extending by a chimney corresponding to the volume of the injection duct 45.

Une fois le moule rempli et l'insert céramique formé, la partie de l'insert correspondant au volume du bras secondaire 30B est supprimé, par exemple par usinage.Once the mold has been filled and the ceramic insert formed, the part of the insert corresponding to the volume of the secondary arm 30B is removed, for example by machining.

La structure de moule telle que proposée présente plusieurs avantages par rapport à un moule conventionnel pour la réalisation d'un tel noyau qui ne comprend qu'un unique chemin d'alimentation.The mold structure as proposed has several advantages over a conventional mold for producing such a core which only comprises a single feed path.

Comme indiqué précédemment, le moule proposé permet de limiter les risques de malvenue ainsi que la formation de zones ségrégées et jets libres dans la pièce, et également les risques de mauvaise jonction de matière. En limitant la formation de zones ségrégées, le moule proposé permet de limiter le retrait différentiel entraînant la déformation et la rupture du noyau. Par ailleurs, le moule proposé permet de limiter les contraintes résiduelles ainsi que la pression observées au sein de la matière injectée, ce qui permet ainsi d'obtenir un noyau de fonderie ayant de meilleures propriétés, et qui est donc moins susceptible de se rompre lors de son utilisation en vue de la formation d'une aube de turbine de turbomachine. La réduction de la pression lors de l'injection permet notamment de réduire l'usure du moule 1. De même, la réduction des taux de cisaillement permet de réduire les risques de séparation de phases.As indicated previously, the proposed mold makes it possible to limit the risks of mishap as well as the formation of segregated zones and free jets in the part, and also the risks of poor material joining. By limiting the formation of segregated zones, the proposed mold makes it possible to limit the differential shrinkage leading to the deformation and rupture of the core. Furthermore, the proposed mold makes it possible to limit the residual stresses as well as the pressure observed within the injected material, which thus makes it possible to obtain a foundry core having better properties, and which is therefore less likely to break during its use for the formation of a turbomachine turbine blade. The pressure reduction during the injection allows in particular to reduce the wear of mold 1. Similarly, the reduction in shear rates makes it possible to reduce the risks of phase separation.

L'emploi d'une telle structure de moule 1 n'a jamais été proposée pour la réalisation de noyaux céramiques en vue de la réalisation d'aubes de turbines de turbomachine.The use of such a mold structure 1 has never been proposed for the production of ceramic cores for the production of turbomachine turbine blades.

Bien que la présente invention ait été décrite en se référant à des exemples de réalisation spécifiques, il est évident que des modifications et des changements peuvent être effectués sur ces exemples sans sortir de la portée générale de l'invention telle que définie par les revendications. En particulier, des caractéristiques individuelles des différents modes de réalisation illustrés/mentionnés peuvent être combinées dans des modes de réalisation additionnels. Par conséquent, la description et les dessins doivent être considérés dans un sens illustratif plutôt que restrictif.Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the different illustrated/mentioned embodiments can be combined in additional embodiments. Accordingly, the description and the drawings should be considered in an illustrative rather than restrictive sense.

II est également évident que toutes les caractéristiques décrites en référence à un procédé sont transposables, seules ou en combinaison, à un dispositif, et inversement, toutes les caractéristiques décrites en référence à un dispositif sont transposables, seules ou en combinaison, à un procédé.It is also obvious that all the characteristics described with reference to a method can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device can be transposed, alone or in combination, to a method.

Claims (9)

  1. A mold (1) for producing a ceramic core by injecting a ceramic composition,
    the mold (1) comprising a body (10) in which a casting core cavity (20) is formed, said cavity (20) comprising a primary cavity (20A) and a secondary cavity (20B) connected by a plurality of segments (20C) allowing the passing of fluid between the primary cavity (20A) and the secondary cavity (20B), the primary cavity (20A) defining recesses of a turbomachine blade,
    said mold (1) being characterized in that it comprises a primary arm (30A) configured in such a way as to allow an injection of ceramic composition into the primary cavity (20A), and a secondary arm (30B) configured in such a way as to allow an injection of ceramic composition into the secondary cavity (20B), and in that the ratio of the volume of the primary cavity (20A) to the volume of the secondary cavity (20B) is equal, plus or minus 15%, to the ratio of the volume of the primary arm (30A) to the volume of the secondary arm (30B).
  2. The mold (1) as claimed in claim 1, wherein the ratio of the contact surface of the primary arm (30A) with the body (10) of the mold (1) with respect to the volume of the primary arm (30A) is equal, plus or minus 20%, to the ratio of the contact surface of the secondary arm (30B) with the body (10) of the mold (1) with respect to the volume of the secondary arm (30B).
  3. The mold (1) as claimed in claim 1, wherein the primary arm (30A) and the secondary arm (30B) are connected to a common injection orifice (50) of the mold (1).
  4. The mold (1) as claimed in claim 3, wherein the primary arm (30A) and the secondary arm (30B) are connected to a feed cavity (40), the feed cavity (40) being connected to an injection orifice (50) of the mold (1).
  5. The mold (1) as claimed in one of claims 1 to 4, wherein the segments (20C) comprise a plurality of segments each having a section having a dimension less than or equal to 1 mm2.
  6. The mold (1) as claimed in one of claims 1 to 5, wherein the primary arm (30A) and the secondary arm (30B) are embodied in a joint plane of the mold (1).
  7. The mold (1) as claimed in one of claims 1 to 6, wherein the primary arm (30A) and the secondary arm (30B) each have a portion of reduced section at the level of their connection with the primary cavity (20A) and the secondary cavity (20B) respectively.
  8. A method for producing a ceramic casting insert for producing a turbine blade, wherein
    - a mold (1) as claimed in one of claims 1 to 7 is supplied,
    - a ceramic composition is injected into the mold (1) in such a way as to fill the primary cavity (20A) and the secondary cavity (20B) via the primary arm (30A) and the secondary arm (30B) respectively.
  9. The method as claimed in claim 8, wherein a subsequent step is performed of finishing the ceramic insert wherein the ceramic material corresponding to the secondary arm (30B) is removed.
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FR1906003A FR3096911B1 (en) 2019-06-06 2019-06-06 Improved foundry mold for forming ceramic cores of turbine blades
PCT/FR2020/050941 WO2020245538A1 (en) 2019-06-06 2020-06-03 Improved foundry mould for the formation of turbine blade ceramic cores

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FR3096911B1 (en) 2021-05-14
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