FR3131702A1 - Assembly for making a molding in removable material of a turbine engine blade - Google Patents

Abstract

Assembly for producing a molding in removable material of a turbine engine blade comprising a mold for injecting said removable material in which a first core element (22) and a second core element (21) are capable of being mounted in a predetermined molding position, the first and second core elements (21, 22) extending in a first direction (Z), the mold comprising:- a first face (20) for molding an underside face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face in a second direction (Y) perpendicular to the first direction (Z), - holding members (P1a, P1f, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in position of the cores in the injection mould, characterized in that the first molding face (20) comprises at least one first holding member ( P1a, P1f, P2a, P2f, P3a, P3f) extending from the first molding face (20) in the second direction (Y), said first holding member (P1a, P1f, P2a, P2f, P3a, P3f) comprising a first bearing point on a first bearing surface of a core element (21, 22), the first bearing surface extending against the core element ( 21, 22), for holding said core element in position in the second direction (Y). Abstract Figure: Figure 1

Description

Set for producing a molding in removable material of a turbomachine blade

The present disclosure relates to the field of turbomachine blades, in particular blades obtained by casting a molten alloy in a mold using the casting technique in removable material, such as for example lost wax.

Classically, the lost wax casting technique consists first of all in making a model in wax, or in any other material that can subsequently be easily removed, of the part to be produced; this model includes an internal part forming a ceramic core which represents the cavities that we wish to see appear inside the blade. The wax model is then dipped several times in slips made of a suspension of ceramic particles to make, through operations called stuccoing and drying, a shell mold.

We then proceed to dewax the shell mold, which is an operation by which the wax or the material constituting the original model is removed from the shell. After this elimination, we obtain a ceramic mold whose cavity reproduces all the shapes of the blade and which still contains the ceramic core intended to generate the internal cavities thereof. The mold then undergoes a heat treatment at high temperature or “baking” which gives it the necessary mechanical properties.

The shell mold is then ready for manufacturing the metal part by casting. After checking the internal and external integrity of the shell mold, the next step consists of pouring a molten metal, which fills the voids between the interior wall of the shell mold and the core, then solidifying it. In the field of lost wax casting, there are currently several solidification techniques, and several casting techniques, depending on the nature of the alloy and the expected properties of the part resulting from casting. It can be directed solidification with columnar structure (DS), directed solidification with single crystal structure (SX) or equiaxed solidification (EX).

After casting the alloy, the shell is broken by a shaking operation. During another step, the ceramic core which remains enclosed in the blade obtained is chemically eliminated. The metal blade obtained then undergoes finishing operations which make it possible to obtain the finished part.

Examples of producing turbine blades using the lost wax casting technique are given in patent applications FR2875425 and FR2874186 of the applicant.

To form the wax model of the blade we use a tool, or wax injection mold, in which the core is placed and then the liquid wax is injected through a channel provided for this purpose.

The search for increased engine performance notably involves more efficient cooling of the turbine blades located immediately downstream of the combustion chamber. This requirement requires the formation inside these blades of more elaborate internal cooling fluid circulation cavities. These blades have the particularity of having several metal walls and therefore require the manufacture of increasingly complex ceramic cores.

Due to the complexity of the cooling cavities to be formed with their separation walls, and their arrangement, one solution consists of making the core in several parts which are assembled and glued. The elementary nuclei are generally linked together at the foot and top. It is in fact a question of controlling the thickness of the walls and partitions formed at the time of casting, without affecting the geometry of the future cavities. The assembly must allow the core to withstand the stresses experienced during the wax injection, dewaxing and then casting stages.

It is therefore necessary to place the different parts of the core very precisely relative to each other in the wax injection mold and to guarantee that the relative positions of the different parts of the core are maintained. Maintaining the different parts of the core as proposed in the current technique consists of fixedly connecting these parts or core elements to the ceramic shell.

As part of the design of a new blade with complex cavities, the solution chosen consists of making the core in two parts, in particular due to the complexity of the cavities forming the cooling circuit and the difficulties encountered in demoulding the core from its injection mold. But due to the too small dimensions of the core parts, and their complex geometry, it is impossible to make a connection between these core parts, for example by gluing, so as to then position the core with its assembled parts in a tool wax injection system comprising a classic isostatic positioning system with six support points.

A difficulty encountered is twofold because it consists on the one hand of very precisely positioning the different parts of the core in the wax injection mold and on the other hand of positioning the different parts of the core relative to each other. . Indeed, the two parts cannot each include their own classic isostatic positioning system with six points of support relative to the mold, because this would double the number of supports to be integrated into the wax injection mold, which terms of mold dimension is not possible. In addition, the two parts of the core being occasionally entangled, certain isostatism points cannot be placed in the wax injection mold. Consequently, the simple positioning of the cores relative to the mold cannot allow complete positioning of the cores relative to each other.

We therefore understand that it is desirable to achieve a different fixing of the cores to each other in the wax injection mold.

The invention aims in particular to provide a simple, effective and economical solution to the problems of the prior art described above.

Summary

For this purpose, the present disclosure proposes an assembly for producing a molding in removable material of a turbomachine blade comprising an injection mold of said removable material in which a first core element and a second core element are capable of come to mount in a predetermined molding position, the first and second core elements extending in a first direction, the mold comprising:
- a first face for molding an intrados face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face in a second direction perpendicular to the first direction,
- members for holding the cores in position in the injection mold,
in which the first molding face comprises at least one first holding member extending from the first molding face in the second direction (Y), said first holding member comprising a first point of support on a first surface of support of a core element, the first support surface extending against the core element, for maintaining said core element in position in the second direction.

Alternatively or additionally, the assembly may include the following characteristics, taken alone or in combination:
- the first molding face comprises three first holding members for the first core element and three first holding members for the second core element;
- each core element extending, in the first direction, between a foot and a head, in which, for each core element, in the first direction, one among the first three holding members is arranged further from the foot than of the head relative to the other two first holding members among the first three holding members;
- each core element foot comprises a free end, the free ends overlapping by complementarity of shape, at least partially;
- the two other first holding members are arranged near the free end of the feet of the first and second core element;
- the first molding face comprises at least a second holding member extending from the first face of the mold, said second holding member comprising a second support point on a second support surface of a core element, the second support surface extending parallel to the first direction, for maintaining said core element in position in the first direction;
- the second member for holding the first core element extends from the first molding face, in the second direction;
- the second member for holding the second core element extends from the first molding face, in the second direction;
- the second member for holding the second core element extends from the first molding face, in a third direction perpendicular to the first and the second direction;
- the assembly further comprises two additional holding members, said additional holding members being common to the first and second core element, and in which: - the first three holding members of the first core element, the second holding member of the first core element and the two additional holding members form a first reference frame for positioning the first core element in the injection mold, and - the first three holding members of the second core element, the second holding member of the second core element and the two additional holding members form a second reference frame for positioning the second core element in the injection mold.

According to another aspect, a method is proposed for producing a molding in removable material of a turbomachine blade, the method comprising:
- provide a first core element and a second core element, said core elements extending in a first direction,
- provide an injection mold for said removable material;
the mold comprising:
- a first face for molding an intrados face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face in a second direction perpendicular to the first direction,
- members for holding the cores in position in the injection mold, among which at least one first holding member extends from the first molding face in the second direction for holding said core element in position along the second direction
the method comprising the step: positioning the first core element and the second core element on the first molding face so that the first holding member has a first support point on a first support surface of a core element, the first support surface extending the first support surface extending against the core element, for maintaining said core element in position in the second direction.

The method described above may also comprise the step:
close the mold by positioning the second molding face on the core elements, the second molding face comprising at least one holding member complementary to the first holding member of the first molding face.

Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

Fig. 1

shows a perspective view of a first and a second core element placed on a first face of an injection mold of a removable material.

Fig. 2

shows the view of the , without the first and the second core element, the first face of the injection mold comprising holding members with support points for holding the leading edge and trailing edge cores.

Fig. 3

shows a view of the leading edge core from its upper surface, on which support points are schematically shown.

Fig. 4

shows a view of the trailing edge core from its extrados face, on which support points are schematized.

Fig. 5

is a sectional view of the along axis AA.

Fig. 6

is a sectional view of the along axis BB.

Fig. 7

is a sectional view of the along the axis BB, illustrating a first example of production of a holding member.

Fig. 8

is a sectional view of the along the axis BB, illustrating a second embodiment of a holding member.

Fig. 9

is a top view of the example illustrated in .

The terms “upstream” and “downstream” are subsequently defined in relation to the direction of flow of gases through a turbomachine, indicated by the arrow F on the .

There illustrates the arrangement of core elements in an injection mold, only a first molding face 20 being illustrated. There illustrates that the core is in the form of a first core element and a second core element, hereinafter referred to as the leading edge core 22 and the trailing edge core 21.

The cores 21, 22 extend in three perpendicular directions in pairs, a first direction Z, hereinafter designated longitudinal direction Z corresponding on the final blade to the longitudinal direction connecting the root to the top of the blade, a second direction Y, hereinafter called transverse direction Y, crossing the intrados and extrados faces of the blade, and a third direction X, hereinafter axial direction X corresponding on the final blade to the upstream/downstream direction (arrow F). On the , only the intrados face of the leading edge core 23a and the intrados face of the trailing edge core 23f is visible. The extrados face of the leading edge core 24a and the extrados face of the trailing edge core 24f, visible for each core in Figures 3 and 4, is arranged facing the first molding face 20. The leading edge 22 and trailing edge 21 cores each comprise a head respectively 25a, 25f and a foot respectively 26a, 26f, the head 25a, 25f being arranged at the opposite end of the foot 26a, 26f, according to the longitudinal direction Z. In the head zone, each of the cores comprises a cutout 27a, 27f, that is to say a portion without material, which extends at least partly perpendicular to the longitudinal direction Z, in the axial direction X. These cutouts also extend from the intrados faces 23a, 23f towards the extrados faces 24a, 24f. These cutouts are intended to form a bottom wall of the blade bath in the final blade. With reference to the longitudinal direction Z and the , the cutout 27a of the leading edge core 22 is delimited by an upper cutout wall 271a and by a lower cutout wall 272a. The cutout 27a of the leading edge core also extends over the entire width of the core, in the axial direction , the cutout 27f of the trailing edge core 21 is delimited by an upper cutout wall 271f and by a lower cutout wall 272f. The cutout of the trailing edge core 27f extends over only part of the width of the core, in the axial direction X. In particular, the cutout of the trailing edge core 27f extends from the edge upstream 28 of the trailing edge core and ends with a longitudinal cutting portion 29 which extends longitudinally in the longitudinal direction Z in the material of the core, and therefore without crossing the core to its downstream edge 30. The feet 26a, 26f further comprise a free end 31a, 31f, corresponding to a non-functional zone of the core. The free ends 31a, 31f can overlap, at least partially. For this purpose, the free end 31f of the trailing edge core may include a tongue 33f. In addition, the free end 31a of the leading edge core may include an indentation 33a. The cavity 33a is designed to receive the tongue 33f. There is thus a complementarity of shape between the imprint 33a and the tongue 33f. This overlap can make it possible to staple the two cores together in order to secure the cores together, for example by drilling the overlapping portion of material then inserting an aluminum rod.

The trailing edge core 21 further comprises a notch 32 on its downstream edge 30. The notch 32 is arranged in the head zone 25a. The notch 32 is substantially U-shaped, oriented so that the opening of the concavity of the U is oriented in the axial direction X.

There illustrates the first molding face 20, devoid of the cores 21, 22. The first molding face comprises holding members P1a, P1f, P2a, P2f, P3a, P3f, P4, P5, P6a, P6f for maintaining the position of the cores into the injection mold. Each holding member maintains in position, in one of the three directions X, Y or Z, the leading edge core 22 or the trailing edge core 21, or the two cores 21,22. In particular, and as detailed below, the leading edge core 22 is placed in the injection mold by a first positioning reference, and the trailing edge core 21 is placed in the mold injection by a second positioning frame of reference. The first positioning reference frame is formed by the holding members P1a, P2a, P3a, P4, P5 and P6a. The second positioning frame of reference is formed by the holding members P1f, P2f, P3f, P4, P5 and P6f (or alternatively a point P6f'). Consequently, the injection mold comprises two different frames of reference, each intended for a different core, the holding members P4 and P5 being holding members common to the two cores.

In particular, the holding members P1a, P1f, P2a, P2f, P3a and P3f (or first holding members) allow the leading edge core 22 or the leading edge core 22 to be maintained in position in the transverse direction Y. leak 21, or two cores 21,22. The holding members P1a, P2a, and P3a are provided for holding in position along the transverse direction Y of the leading edge core 22. The holding members P1f, P2f, and P3f are provided for holding in position following the transverse direction Y of the trailing edge core 21. Each of the holding members P1a, P1f, P2a, P2f, P3a and P3f extends from the first molding face 20, in the transverse direction Y. Each of these members is in support against one of the two cores, which prevents the movement of the cores in the transverse direction Y.

In particular, the holding members P1a, P2a, P2f and P1f are arranged in the foot zone 26a, 26f of the cores. These holding members P1a, P2a, P2f and P1f are aligned in the axial direction X. The holding members P1a, P2a, P2f and P1f are arranged near the free end 31a, 31f of the cores. In other words the holding members P1a, P2a, P2f and P1f are arranged outside the free end of the cores, but in the foot zone 26a, 26f of the cores. The holding members P1a, P2a, P2f and P1f end in a support surface for the respective core, each of these support surfaces being substantially flat. In addition, each of these support surfaces is substantially perpendicular to the transverse direction Y. These surfaces are also located outside the functional zone.

The holding members P3a and P3f are arranged in the head zone 26a, 26f of the cores. The holding member P3a and the holding member P3f are offset in the longitudinal direction Z. In other words the holding members P3a and P3f are not aligned in the axial direction X. The holding members P3a and P3f end with a support surface for the respective core, each of these support surfaces following the shape of the contact zone of the core. In other words, for optimal support, the bearing surfaces of the holding members P3a and P3f match the shape of the surface of the core zone with which they are in contact.

Alternatively and in addition, the second molding face may comprise holding members similar to the holding members described above, so as to lock the cores in position in the transverse direction Y.

The first molding face 20 may further comprise the holding members P6a and P6f (or second holding member). The holding members P6a and P6f allow the leading edge core 22 or the trailing edge core 21 to be maintained in position in the longitudinal direction Z, for example. Each of these members bears against the edge core d respectively. attack 22, and the trailing edge core 21, which prevents the movement of the cores in the longitudinal direction Z. The holding member P6a is provided for example for maintaining position in the longitudinal direction Z of the edge core attack member 22. The holding member P6a extends from the first molding face, in the transverse direction Y. The holding member P6a bears against the lower wall of the cutout 272a of the edge core. attack 22. The holding member P6f is provided for example for maintaining in position along the longitudinal direction Z of the trailing edge core 21. The holding member P6f extends from the first molding face, following the direction axial X, in the direction from downstream to upstream. The holding member P6f rests in the notch 32 of the downstream edge 30 of the trailing edge core 21.

Alternatively, we can provide a holding member P6'f instead of the holding member P6f. The holding member P6'f is provided for maintaining the trailing edge core 21 in position along the longitudinal direction Z. The holding member P6'f extends from the first molding face 20, following the direction transverse Y. The holding member P6'f bears against the lower cutout wall 272f of the trailing edge core 21. In addition, the holding members P6a and P6'f are arranged so that the cutouts of the two cores are substantially aligned in the axial direction

Only one of the two holding members P6f and P6'f is used to produce the wax molding, to position the trailing edge core 21 in the longitudinal direction Z. Depending on the holding member used P6f or P6'f, the The unused holding member is removed from the molding surface so as not to create a hyperstatic system. The choice of using one point or the other depends on the distribution of the expansion of the two cores sought during the casting of the alloy.

Indeed, the holding member P6 makes it possible to distribute the expansion of the trailing edge core 21 in the longitudinal direction Z, towards the head 25f and towards the foot 26f, avoiding having too great a difference in length with the leading edge core 22, particularly in the event of very different expansions between the two cores. On the other hand, the holding member P6'f is advantageously used so as to control the dimensions of a so-called bathtub bottom wall present in the final blade. The bottom wall of the bathtub is materialized by the cutouts 27a, 27f of the cores, which form a portion filled with material in the final blade. The bottom of the bathtub is substantially planar, and extends in the transverse direction Y and the axial direction one from the other, a portion of material, called the bathtub bottom wall, separates the bathtub bottom into two parts, arranged at different levels in the longitudinal direction Z. The wall 26 extends in the longitudinal direction Z, from the bottom of the bathtub 24. The height of the wall, the longitudinal direction Z, is a characteristic which must be controlled in order to meet the aerodynamic performance of the blade. It is indeed desirable that the height of the wall is as small as possible, so as to avoid as much as possible a too significant difference in level between the parts of the bathtub base. Consequently, the holding member P6'f, associated with the holding member P6a, places the cutouts 27a and 27f of the cores in the same plane, which makes it possible to obtain two bathtub bottom parts substantially in the same plane. plane perpendicular to the longitudinal direction Z.

The first molding face further comprises the holding members P4 and P5 (or additional holding members). The holding members P4 and P5 allow the leading edge core 22 or the trailing edge core 21, or the two cores 21,22, to be held in position in the axial direction X. The holding members P4 and P5 are holding members common to the two leading edge 22 and trailing edge 21 cores. The holding members P4 and P5 each comprise for this purpose a first point of support on the core leading edge and a second support point on the trailing edge core. The holding members P4 and P5 together block the rotation of the cores around the transverse axis Y. Each of the holding members P4 and P5 extends from the first molding face, in the transverse direction Y.

Figures 7, 8 illustrate examples of production of a holding member, in a sectional view in the axial direction is a top view of the example of the . These exemplary embodiments can apply for example to one or the other of the holding members P4, P5 or to the two holding members P4 and P5. In these examples, the holding member comprises a base 30 and a head 31. The base 30 is cylindrical. The base 30 is also arranged in the mold, and can pivot around its axis of rotation R, coincident with its axis of revolution. The head 31 is a rod which extends in the transverse direction Y, from the base 30. In the example illustrated in , the head 31 is aligned with the axis of rotation R. Consequently, the rotation of the base 30 the holding member around the axis of rotation R does not cause offset of the head 31, it is that is to say translational movement in the plane defined by the transverse Y and longitudinal Z directions. In the example illustrated in Figures 8 and 9, the head 31 is eccentric with respect to the base 30. In other words, the head 31 is not aligned with the axis of rotation R of the base 30. Consequently, the head 31 has, in this example, an eccentric function: the head 31 moves in a plane defined by the directions transverse Y and longitudinal Z. This example advantageously makes it possible to move the leading edge core 22 and the trailing edge core 21, for adjusting their position in the mold, the leading edge cores 22 and the leading edge cores leak 21 cooperating with the holding member, as detailed later in the presentation.

The holding member P4 can be arranged in the head zone 25a, 25f. The holding member P5 can be arranged in the foot zone 26a, 26f, at the junction with the free end 31a, 31f. The holding members P4 and P5 can also be aligned in the longitudinal direction Z. The holding members P4 and P5 are also arranged in a non-functional zone, that is to say outside the room.

The holding member P4 is visible at the , corresponding to a sectional view along axis AA of the . It can be seen that the holding member P4 comprises a first support point on the leading edge core P4a, and a second support point on the trailing edge core P4f. The first support point P4a ensures blocking of the leading edge core 22 in a direction F1 going from upstream to downstream. Also, the second support point P4f ensures blocking of the trailing edge core in a direction F2 going from downstream to upstream, that is to say a direction opposite to the direction of blocking of the edge core attack. The holding member P4 can also be through. By crossing, we understand that the holding member P4 extends from the first molding face 20 to the intrados face of the trailing edge core 23f, respectively crossing the extrados face of the edge core leading edge 24a, the intrados face of the leading edge core 23a and the extrados face of the trailing edge core 24f.

The holding member P5 is visible at the , corresponding to a sectional view along the axis BB of the . It can be seen that the holding member P5 comprises a first support point on the leading edge core P5a, and a second support point on the trailing edge core P5f. The first support point of the holding member P5a ensures blocking of the leading edge core 22 in a direction F1 going from upstream to downstream. Also, the second point of support of the holding member P5f ensures blocking of the trailing edge core 21 in a direction F2 going from downstream to upstream, that is to say a direction opposite to the blocking direction F1 of the leading edge core. The holding member P5 can also be through. By crossing, we understand that the holding member P5 extends from the first molding face 20 towards the intrados face 23a, 23f of the trailing edge and leading edge cores, and beyond , in the transverse direction Y, of the extrados face 24a, 24f of the cores. However, as visible in the , the holding member P5 crosses, in the transverse direction Y, only an alignment defined by the extrados faces 24a, 24f of the two cores, without crossing the cores. In other words, the holding member P5 is arranged between the two cores, and extends beyond their extrados face 24a, 24f, without however extending beyond their intrados face 23a, 23f. Alternatively, the holding member P5 can extend beyond their intrados face 23a, 23f.

In addition, the holding member P4 and/or the holding member P5 can be movable between a holding position and a retracted position. In the holding position, visible at and 5, which can also be called the deployed position, the holding member is in contact with at least one of the cores. In the retracted position, the holding member is set back relative to the cores, its length being less than its length in the holding position. The mobility of the holding member(s) makes it easy to unmold the part obtained. Indeed, when the holding member, in its deployed position, is arranged along an axis different from the demolding axis, its retracted position allows the holding member not to oppose demolding. The holding member further comprises a retraction mechanism, ensuring mobility between the retracted position and the holding position.

Alternatively, the holding member P4 and/or the holding member P5 may further comprise a spacing means D4, D5 between their first and second support points. The spacing means guarantees a spacing (or spacing) of a constant spacing distance between the first and second support points, the spacing distance being measured for example in the axial direction spacing D4, D5 keeps the two cores spaced apart from each other, without them being in contact, that is to say without the cores touching each other. Given that the cores extend in the three directions of space, the spacing distance can be measured in the longitudinal direction Z or the transverse direction Y. A spacing means is for example materialized by the diameter of the maintaining organ. The holding member can for example have a constant diameter over its entire length. According to another example, the holding member can have a smaller diameter towards its free end, and a larger diameter towards its base (that is to say on the side of the first molding face).

Alternatively, the holding member P4 and/or the holding member P5 may further comprise means for adjusting the position of the cores in the first molding face. For example, the adjustment means is an eccentric, which can be rotated around the transverse direction Y to shift the two cores in the plane formed by the transverse and axial directions.

In another alternative, the first molding face 20 may further comprise counter-supports, as illustrated in . It can thus be seen that the first molding face 20 comprises, for the leading edge core 22, a first counter-support 41a, and a second counter-support 42a. For the trailing edge core 21, the first molding face 20 also includes a first counter-support 41f, and a second counter-support 42f. The counter-supports help maintain the cores in the mold, as well as the contact of the cores with the support points. For example, as visible in , the first counter-support 41a of the leading edge core 22 presses the leading edge core against the holding member P4. In addition, the first counter-support 41f of the trailing edge core 21 presses the trailing edge core 21 against the holding member P4. Also, as visible in the , the second counter-support 42a of the leading edge core 22 presses the leading edge core against the holding member P5. Furthermore, the first counter-support 41f of the trailing edge core 21 presses the trailing edge core 21 against the holding member P5. As also visible in Figures 4 and 5, the first counter-supports 41a, 41f and respectively the second counter-supports 42a, 42f extend in the axial direction X. In addition, the first counter-supports 41a, 41f and respectively the second counter-supports 42a, 42f can be aligned in the axial direction X with the respective holding members P4 and P5.

We now describe a process for producing a molding of a turbomachine blade in removable material, the process comprising:
- provide the leading edge core 22 and the trailing edge core 21;
- provide the injection mold for the removable material;
- position the leading edge core 22 and the trailing edge core 21 on the first molding face 20. In this position, the first holding member has a first support point on a first support surface d a core element, the first bearing surface extending against the core, for maintaining said core element in position in the second direction. Furthermore, in this position, the holding member(s) P4, P5 at least partially crosses the cores of the leading edge 22 and the trailing edge 21.

Alternatively, the method may comprise: closing the mold by positioning the second molding face on the core elements, with at least one complementary holding member.

Claims (12)

Assembly for producing a molding in removable material of a turbomachine blade comprising an injection mold of said removable material in which a first core element (22) and a second core element (21) are able to be mounted in a predetermined molding position, the first and second core elements (21, 22) extending in a first direction (Z), the mold comprising:
- a first face (20) for molding an intrados face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face in a second direction (Y) perpendicular to the first direction (Z),
- holding members (P1a, P1f, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in the position of the cores in the injection mold,
characterized in that the first molding face (20) comprises at least one first holding member (P1a, P1f, P2a, P2f, P3a, P3f) extending from the first molding face (20) in the second direction ( Y), said first holding member (P1a, P1f, P2a, P2f, P3a, P3f) comprising a first support point on a first support surface of a core element (21, 22), the first surface support extending against the core element (21, 22), for maintaining said core element in position in the second direction (Y). Assembly according to claim 1, in which the first molding face (20) comprises three first holding members (P1a, P2a, P3a) for the first core element (22) and three first holding members (P1f, P2f, P3f ) for the second core element (21). Assembly according to claim 2, each core element (21, 22) extending, in the first direction (Z), between a foot (26f, 26a) and a head (25f, 25a), in which, for each element of core (21, 22), in the first direction (Z), one among the first three holding members (P3f, P3a) is arranged further from the foot (26f, 26a) than from the head (25f, 25a) by relative to the other two first maintaining members (P1f, P1a, P2f, P2a) among the first three maintaining members (P1a, P1f, P2a, P2f, P3a, P3f). Assembly according to claim 3, in which each foot (26a, 26f) of core element (22, 21) comprises a free end (31a, 31f), the free ends (31a, 31f) overlapping by complementarity of shape, at least partially. Assembly according to claim 4, in which the two other first holding members (P1f, P1a, P2f, P2a) are arranged near the free end (31a, 31f) of the feet (26a, 26f) of the first and second element core (22, 21). Assembly according to any one of the preceding claims, in which the first molding face (20) comprises at least one second holding member (P6a, P6f, P6'f) extending from the first face of the mold (20), said second holding member (P6a, P6f, P6'f) comprising a second support point on a second support surface of a core element (22, 21), the second support surface extending parallel in the first direction, for maintaining the position of said core element (22, 21) in the first direction (Z). Assembly according to claim 6, in which the second member for holding the first core element (P6a) extends from the first molding face (20), in the second direction (Y). Assembly according to claim 6 or 7, in which the second member for holding the second core element (P6'f) extends from the first molding face (20), in the second direction (Y). Assembly according to claim 6 or 7, in which the second member for holding the second core element (P6f) extends from the first molding face (20), in a third direction (X) perpendicular to the first (Z) and to the second direction (Y). Assembly according to any one of claims 6 to 9, further comprising two additional holding members (P4, P5), said additional holding members (P4, P5) being common to the first and second core elements (22, 21). , and in which:
- the first three holding members (P1a, P2a, P3a) of the first core element (22), the second holding member of the first core element (P6a) and the two additional holding members (P4, P5) form a first reference frame for positioning the first core element (22) in the injection mold, and
- the first three holding members (P1f, P2f, P3f) of the second core element (21), the second holding member of the second core element (P6f, P6f') and the two additional holding members (P4, P5 ) form a second reference frame for positioning the second core element (21) in the injection mold. Process for producing a molding of a turbomachine blade in removable material, the process comprising:
- providing a first core element (22) and a second core element (21), said core elements extending in a first direction (Z),
- provide an injection mold for said removable material;
the mold comprising:
- a first face for molding (20) an intrados face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face in a second direction (Y) perpendicular to the first direction (Z),
- holding members (P1a, P1f, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in the position of the cores in the injection mold, among which at least one first holding member (P1a, P1f , P2a, P2f, P3a, P3f) extends from the first molding face (20) in the second direction (Y) for maintaining said core element in position in the second direction (Y)
the method being characterized in that it comprises the step: positioning the first core element (22) and the second core element (21) on the first molding face (20) so that the first holding member ( P1a, P1f, P2a, P2f, P3a, P3f) has a first support point on a first support surface of a core element (22, 21), the first support surface extending against the core element (21, 22), for maintaining said core element (22, 21) in position in the second direction (Y). A method according to claim 11, further comprising the step:
close the mold by positioning the second molding face on the core elements (21, 22), the second molding face comprising at least one holding member complementary to the first holding member (P1a, P1f, P2a, P2f, P3a, P3f, P6a, P6f) of the first molding face (20).