ARRANGEMENT FOR PRODUCING A MOLDED BODY FROM REMOVABLE MATERIAL OF A TURBOMACH MACHINE SHELL

Description

Domaine technique

[0001] This disclosure relates to the field of turbomachine blades, in particular to blades obtained by casting a molten alloy into a mold using the casting technique in disposable material, such as lost wax. Technique antérieure

[0002] Traditionally, the lost-wax casting technique begins by creating a model of the part to be produced, either in wax or any other easily removable material. This model includes an internal ceramic core that represents the cavities to be created within the bore. The wax model is then repeatedly dipped in slips made from a suspension of ceramic particles to create, through processes known as stenciling and drying, a shell mold.

[0003] The next step involves dewaxing the shell mold, an operation by which the wax or material constituting the original model is removed from the shell. After this removal, a ceramic mold is obtained whose cavity reproduces all the shapes of the blade and which still contains the ceramic core intended to generate its internal cavities. The mold then undergoes a high-temperature heat treatment, or "firing," which gives it the necessary mechanical properties.

[0004] The shell mold is then ready for casting the metal part. After checking the internal and external integrity of the shell mold, the next step is to pour molten metal into the mold, filling the voids between the inner wall of the shell mold and the core, and then solidify it. In the field of lost-wax casting, several solidification and casting techniques are currently used, depending on the alloy and the desired properties of the resulting part. These include columnar directional solidification (DS), single-crystal directional solidification (SX), and equiaxed solidification (EX).

[0005] After the alloy is poured, the shell is broken off using a shakeout operation. In a subsequent step, the ceramic core remaining within the resulting blade is chemically removed. The metal blade then undergoes finishing operations to produce the finished part.

[0006] Examples of turbine blade production using the lost-wax casting technique are given in the applicant's patent applications FR2875425 and FR2874186, as well as in patent US4283835.

[0007] To form the wax model of the dawn, a tool, or wax injection mold, is used, in which the core is placed and then liquid wax is injected through a channel provided for this purpose.

[0008] The pursuit of increased engine performance notably involves more efficient cooling of the turbine blades located immediately downstream of the combustion chamber. This requirement necessitates the creation of more sophisticated internal cavities for cooling fluid circulation within these blades. These blades are characterized by having multiple metallic walls and therefore require the manufacture of increasingly complex ceramic cores.

[0009] Due to the complexity of the cooling cavities to be formed, including their partition walls and their arrangement, one solution is to create the core in several parts that are then assembled and glued together. These individual cores are generally joined at their base and top. This allows for precise control of the wall and partition thicknesses formed during the casting process, without affecting the geometry of the future cavities. The assembly must enable the core to withstand the stresses experienced during the wax injection, dewaxing, and casting stages.

[0010] It is therefore essential to position the various parts of the core very precisely relative to one another within the wax injection mold and to ensure that their relative positions are maintained. Maintaining the different parts of the core, as proposed in the current technique, involves permanently attaching these parts or core elements to the ceramic shell.

[0011] In the design of a new blade with complex cavities, the chosen solution is to manufacture the core in two parts, primarily due to the complexity of the cavities forming the cooling circuit and the difficulties encountered when demolding the core from its injection mold. However, because the core parts are too small and have complex geometries, it is impossible to create a bond between them, for example by gluing, in order to then position the core with its assembled parts in a wax injection mold equipped with a conventional six-point isostatic positioning system.

[0012] One difficulty encountered is twofold: firstly, precisely positioning the different parts of the core within the wax injection mold, and secondly, positioning these parts relative to each other. The two parts cannot each have their own conventional six-point isostatic positioning system relative to the mold, as this would double the number of supports required in the wax injection mold, which is impractical given the mold's dimensions. Furthermore, since the two core parts are partially interlocked, certain isostatic points cannot be placed within the wax injection mold. Consequently, simply positioning the cores relative to the mold is insufficient for complete positioning of the cores relative to each other.

[0013] It is therefore understandable that it is desirable to achieve a different fixing of the nuclei to each other in the wax injection mold.

[0014] The invention aims in particular to provide a simple, effective and economical solution to the problems of the prior art described above. Résumé

[0015] To this end, this disclosure proposes an assembly for producing a mold of a turbomachine blade in disposable material, comprising an injection mold for said disposable material in which a first core element and a second core element are suitable for mounting in a predetermined molding position, the first and second core elements extending in a first direction, the mold comprising: a first face for molding the intrados face of the blade and a second face for molding the extrados face of the blade arranged opposite the first face along a second direction perpendicular to the first direction, retaining devices for positioning the cores in the injection mold, at least one first retaining member extending from the first face of the mold in the second direction and passing at least partially through the first and second core elements, the first retaining member comprising a first support point on the first core element and a second support point on the second core element.

[0016] Alternatively or additionally, the set may include the following features, taken alone or in combination: the first core element and the second core element are shaped so that the first support point of the first retaining member ensures a locking of the first core element in a first direction of a third direction perpendicular to the first and second directions and the second support point of the first retaining member ensures a locking of the second core element in a second direction of the third direction, opposite to the first direction; a second retaining member extends from the first molding face in the second direction, the second retaining member comprising a first support point on the first core element and a second support point on the second core element, said first support point and second support point of the second retaining member being distinct from the first support point and second support point of the first retaining member;the first core element and the second core element are shaped so that the first support point of the second retaining member ensures a locking of the first core element in the first direction of a third direction perpendicular to the first and second directions and the second support point of the second retaining member ensures a locking of the second core element in a second direction of the third direction, opposite to the first direction; the second retaining member includes a spacing means between the first support point of the second retaining member and the second support point of the second retaining member, the spacing means ensuring, during the making of the molding in disposable material, a spacing of a constant distance between said support points in the third direction;The first retaining member comprises a spacing means between the first support point of the first retaining member and the second support point of the first retaining member, the spacing means ensuring, during the molding process in disposable material, a constant spacing between said support points in at least one of the following directions: the first, the second, or the third; the first retaining member and / or the second retaining member is movable between a holding position for at least one core element and a retracted position, the retaining member comprising a retraction mechanism for positioning the retaining member in the holding position or in the retracted position; the first retaining member and / or the second retaining member comprises a rotation axis and an eccentric head relative to the rotation axis and cooperating with the first core element and the second core element.

[0017] In another aspect, a process is proposed for producing a mold of a turbomachine blade from a disposable material, the process comprising: providing a first core element and a second core element, said core elements extending in a first direction, providing an injection mold for said disposable 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, retaining elements for holding the cores in position in the injection mold, among which at least one first retaining element extends from the first molding face in 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 retaining element passes at least partially through the first and second core elements and includes a first support point on the first core element and a second support point on the second core element.

[0018] The process may further include: the step: positioning the first core element and the second core element on the first molding face so that the second retaining member includes a first support point on the first core element and a second support point on the second core element, the mold further including a second retaining member extending from the first molding face in the second direction. Brève description des dessins

[0019] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which: Fig. 1 [ Fig. 1 ] shows a perspective view of a first and second core element placed on a first face of an injection mold of a disposable material. Fig. 2 [ Fig. 2 ] shows the view of the figure 1 , without the first and second core elements, the first face of the injection mold includes retaining elements with support points for retaining the leading edge and trailing edge cores. Fig. 3 [ Fig. 3 ] shows a view of the leading edge core from its upper surface, on which support points are schematically represented. Fig. 4 [ Fig. 4 ] shows a view of the trailing edge core from its upper surface, on which support points are schematically represented. Fig. 5 [ Fig. 5 ] is a cross-sectional view of the figure 1 along axis AA. Fig. 6 [ Fig. 6 ] is a cross-sectional view of the figure 1 along the BB axis. Fig. 7 [ Fig. 7 ] is a cross-sectional view of the figure 1 along axis BB, illustrating a first example of the realization of a retaining element. Fig. 8 [ Fig. 8 ] is a cross-sectional view of the figure 1 along axis BB, illustrating a second example of the realization of a retaining element. Fig. 9 [ Fig. 9 ] is a top view of the example shown in the figure 8 . Description des modes de réalisation

[0020] The terms "upstream" and "downstream" are subsequently defined in relation to the direction of gas flow through a turbomachine, indicated by arrow F on the figure 1 .

[0021] There figure 1 illustrates the arrangement of core elements in an injection mold, with only the first mold face 20 shown. figure 1 illustrates that the core consists 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.

[0022] The cores 21 and 22 extend along three directions perpendicular to each other: a first direction Z, hereinafter referred to as the longitudinal direction Z, corresponding on the final blade to the longitudinal direction connecting the root to the tip of the blade; a second direction Y, hereinafter referred to as the transverse direction Y, crossing the intrados and extrados faces of the blade; and a third direction X, hereinafter referred to as the axial direction X, corresponding on the final blade to the upstream / downstream direction (arrow F). On the figure 1 Only the lower surface face of the leading edge core 23a and the lower surface face of the trailing edge core 23f are visible. The upper surface face of the leading edge core 24a and the upper surface face of the trailing edge core 24f are visible for each core on the figures 3 And 4, is arranged with respect to the first molding face 20. The leading edge cores 22 and trailing edge cores 21 each comprise a head 25a, 25f respectively and a foot 26a, 26f respectively, the head 25a, 25f being arranged at the opposite end of the foot 26a, 26f, along the longitudinal direction Z. In the head area, each of the cores includes a cutout 27a, 27f, i.e., a portion without material, which extends at least partially perpendicular to the longitudinal direction Z, in the axial direction X. These cutouts also extend from the lower surfaces 23a, 23f to the upper surfaces 24a, 24f. These cutouts are intended to form a blade trough bottom wall in the final blade. With reference to the longitudinal direction Z and the figure 3 The cutout 27a of the leading edge core 22 is delimited by an upper cutout wall 271a and a lower cutout wall 272a. The cutout 27a of the leading edge core also extends across the entire width of the core, along the axial direction X. With reference to the longitudinal direction Z and the figure 4 The cutout 27f of the trailing edge core 21 is delimited by an upper cutout wall 271f and a lower cutout wall 272f. The cutout of the trailing edge core 27f extends over only a portion of the core's width, along the axial direction X. In particular, the cutout of the trailing edge core 27f extends from the leading edge 28 of the trailing edge core and terminates with a longitudinal portion of the cutout 29 that extends longitudinally along the longitudinal direction Z within the core material, and thus without traversing the core to its trailing edge 30. The feet 26a, 26f further include a free end 31a, 31f, corresponding to a non-functional area of ​​the core. The free ends 31a, 31f may overlap, at least partially. For this purpose, the free end 31f of the trailing edge core may include a tab 33f.Furthermore, the free end 31a of the leading edge core may include a recess 33a. The recess 33a is designed to receive the tab 33f. There is thus a complementary shape between the recess 33a and the tab 33f. This overlap allows the two cores to be clipped together to achieve a core fixation, for example by drilling through the overlapping portion of material and then inserting an aluminum rod.

[0023] The trailing edge core 21 further includes a notch 32 on its downstream edge 30. The notch 32 is arranged in the head area 25f. 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.

[0024] There figure 2 Figure 20 illustrates the first mold face, which lacks the cores 21 and 22. The first mold face includes retaining elements P1a, P1f, P2a, P2f, P3a, P3f, P4, P5, P6a, and P6f for holding the cores in position within the injection mold. Each retaining element holds the leading edge core 22, the trailing edge core 21, or both cores 21 and 22 in position along one of three directions (X, Y, or Z). Specifically, and as detailed below, the leading edge core 22 is positioned in the injection mold by a first positioning reference frame, and the trailing edge core 21 is positioned in the injection mold by a second positioning reference frame. The first positioning reference frame consists of the retaining elements P1a, P2a, P3a, P4, P5, and P6a. The second positioning reference frame is formed by the support elements P1f, P2f, P3f, P4, P5 and P6f (or alternatively by a point P6f').Therefore, the injection mold comprises two different reference frames, each intended for a different core, with the retaining elements P4 and P5 being common retaining elements for both cores.

[0025] In particular, the retaining elements P1a, P1f, P2a, P2f, P3a, and P3f allow the leading edge core 22 or the trailing edge core 21, or both cores 21 and 22, to be held in position along the transverse Y direction. Retaining elements P1a, P2a, and P3a are designed to hold the leading edge core 22 in position along the transverse Y direction. Retaining elements P1f, P2f, and P3f are designed to hold the trailing edge core 21 in position along the transverse Y direction. Each of the retaining elements P1a, P1f, P2a, P2f, P3a, and P3f extends from the first molded face 20 along the transverse Y direction. Each of these elements bears against one of the two cores, which prevents movement of the cores along the transverse Y direction.

[0026] In particular, the retaining elements P1a, P2a, P2f, and P1f are arranged in the base area 26a, 26f of the cores. These retaining elements P1a, P2a, P2f, and P1f are aligned along the axial direction X. The retaining elements P1a, P2a, P2f, and P1f are arranged near the free end 31a, 31f of the cores. In other words, the retaining elements P1a, P2a, P2f, and P1f are arranged outside the free end of the cores, but within the base area 26a, 26f of the cores. The retaining elements P1a, P2a, P2f, and P1f terminate in a bearing surface for the respective core, each of these bearing surfaces being substantially flat. Furthermore, each of these support surfaces is substantially perpendicular to the transverse direction Y. These surfaces are also located outside the functional zone.

[0027] The retaining elements P3a and P3f are arranged in the head zone 26a, 26f of the cores. Retaining elements P3a and P3f are offset along the longitudinal Z direction. In other words, retaining elements P3a and P3f are not aligned along the axial X direction. Retaining elements P3a and P3f terminate with a bearing surface for the respective core, each of these bearing surfaces conforming to the shape of the core's contact zone. In other words, for optimal retention, the bearing surfaces of retaining elements P3a and P3f follow the shape of the core zone with which they are in contact.

[0028] Alternatively and in addition, the second molding face may include retaining elements similar to the retaining elements described above, so as to lock the cores in position along the transverse Y direction.

[0029] The first mold face 20 may further include retaining elements P6a and P6f. Retaining elements P6a and P6f allow the leading edge core 22 or the trailing edge core 21 to be held in position along the longitudinal direction Z, for example. Each of these elements bears against the leading edge core 22 and the trailing edge core 21, respectively, which prevents movement of the cores along the longitudinal direction Z. Retaining element P6a is provided, for example, for holding the leading edge core 22 in position along the longitudinal direction Z. Retaining element P6a extends from the first mold face along the transverse direction Y. Retaining element P6a bears against the lower wall of the cutout 272a of the leading edge core 22. Retaining element P6f is provided, for example, for holding the trailing edge core 21 in position along the longitudinal direction Z.The retaining member P6f extends from the first molding face, along the axial direction X, from downstream to upstream. The retaining member P6f bears against the notch 32 of the downstream edge 30 of the trailing edge core 21.

[0030] Alternatively, a retaining member P6'f may be provided instead of the retaining member P6f. The retaining member P6'f is designed to hold the trailing edge core 21 in position along the longitudinal direction Z. The retaining member P6'f extends from the first mold face 20, along the transverse direction Y. The retaining member P6'f bears against the lower cutout wall 272f of the trailing edge core 21. Furthermore, the retaining members P6a and P6'f are arranged so that the cutouts of the two cores are substantially aligned along the axial direction X.

[0031] Only one of the two holding elements, P6f and P6'f, is used for the wax casting to position the trailing edge core 21 along the longitudinal Z direction. Depending on which holding element is used (P6f or P6'f), the unused holding element is removed from the casting surface to avoid creating a statically indeterminate system. The choice of which point to use depends on the desired distribution of thermal expansion between the two cores during the alloy casting process.

[0032] Indeed, the retaining element P6 distributes the expansion of the trailing edge core 21 in the longitudinal direction Z, towards the tip 25f and the root 26f, preventing an excessive length difference with the leading edge core 22, particularly in cases of very different expansion rates between the two cores. Furthermore, the retaining element P6'f is advantageously used to control the dimensions of a so-called "bathtub bottom" wall present in the final blade. The bathtub bottom wall is formed by the cutouts 27a, 27f in the cores, which constitute a material-filled portion in the final blade. The bathtub bottom is substantially flat and extends along the transverse direction Y and the axial direction X.Because the cores do not touch, meaning they are not in contact with each other, a portion of material, called the tub bottom wall, separates the tub bottom into two parts, arranged at different levels along the longitudinal direction Z. The wall 26 extends along the longitudinal direction Z from the tub bottom 24. The height of the wall, along the longitudinal direction Z, is a characteristic that must be controlled to meet the aerodynamic performance requirements of the blade. It is desirable that the wall height be as small as possible to minimize any significant difference in level between the tub bottom sections. Therefore, the retaining element P6'f, in conjunction with the retaining element P6a, positions the cutouts 27a and 27f of the cores on the same plane, thus creating two tub bottom sections that are essentially in the same plane perpendicular to the longitudinal direction Z.

[0033] The first mold face also includes retaining elements P4 and P5. Retaining elements P4 and P5 hold the leading edge core 22 or the trailing edge core 21, or both cores 21 and 22, in position along the axial direction X. Retaining elements P4 and P5 are common retaining elements for both the leading edge core 22 and the trailing edge core 21. Each retaining element P4 and P5 includes, for this purpose, a first bearing point on the leading edge core and a second bearing point on the trailing edge core. Retaining elements P4 and P5 together prevent the rotation of the cores about the transverse axis Y. Each retaining element P4 and P5 extends from the first mold face along the transverse direction Y.

[0034] THE figures 7, 8 illustrate examples of the implementation of a retaining device, in a cross-sectional view along the axial direction X. The figure 9 is a top view of the example of the figure 8 These embodiment examples can be applied, for instance, to one or the other of the retaining members P4, P5, or to both retaining members P4 and P5. In these examples, the retaining member comprises a base 30 and a head 31. The base 30 is cylindrical. The base 30 is further arranged in the mold and can pivot about its axis of rotation R, which coincides with its axis of revolution. The head 31 is a rod extending along the transverse direction Y from the base 30. In the example illustrated in the figure 7 The head 31 is aligned with the axis of rotation R. Consequently, the rotation of the base 30, the retaining element, around the axis of rotation R does not cause any displacement of the head 31, that is, no translational movement in the plane defined by the transverse Y and longitudinal Z directions. In the example illustrated in figures 8 et 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 transverse Y and longitudinal Z directions. This example advantageously allows the leading edge core 22 and the trailing edge core 21 to be moved for adjusting their position in the mold, the leading edge core 22 and trailing edge core 21 cooperating with the holding member, as detailed later in the exposition.

[0035] The retaining member P4 (or first retaining member) can be arranged in the head area 25a, 25f. The retaining member P5 (or second retaining member) can be arranged in the foot area 26a, 26f, at the junction with the free end 31a, 31f. The retaining members P4 and P5 can also be aligned along the longitudinal direction Z. The retaining members P4 and P5 are otherwise arranged in a non-functional area, i.e., outside the part.

[0036] The P4 retaining organ is visible at the figure 5 , corresponding to a cross-sectional view along axis AA of the figure 1 It can be seen that the retaining element 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 secures the leading edge core 22 in a direction F1 from upstream to downstream. Similarly, the second support point P4f secures the trailing edge core in a direction F2 from downstream to upstream, that is, in the opposite direction to the leading edge core's locking. The retaining element P4 can also be through-bolted. By passing through, we understand that the retaining member P4 extends from the first molding face 20 to the intrados face of the trailing edge core 23f, passing respectively through the extrados face of the leading edge core 24a, the intrados face of the leading edge core 23a and the extrados face of the trailing edge core 24f.

[0037] The P5 retaining organ is visible at the figure 6 , corresponding to a cross-sectional view along the BB axis of the figure 1 It can be seen that the retaining element P5 comprises a first bearing point on the leading edge core P5a, and a second bearing point on the trailing edge core P5f. The first bearing point of the retaining element P5a secures the leading edge core 22 in a direction F1 from upstream to downstream. Similarly, the second bearing point of the retaining element P5f secures the trailing edge core 21 in a direction F2 from downstream to upstream, that is, in the opposite direction to the locking direction F1 of the leading edge core. The retaining element P5 may also be through-bolted. By "through," we understand that the retaining element P5 extends from the first molded face 20 towards the intrados face 23a, 23f of the trailing and leading edge cores, and beyond, along the transverse direction Y, to the extrados face 24a, 24f of the cores. However, as visible at the figure 6 The retaining element P5, along the transverse direction Y, traverses only an alignment defined by the extrados faces 24a, 24f of the two nuclei, without passing through the nuclei themselves. In other words, the retaining element P5 is positioned between the two nuclei and extends beyond their extrados faces 24a, 24f, but not beyond their intrados faces 23a, 23f. Alternatively, the retaining element P5 may extend beyond their intrados faces 23a, 23f.

[0038] Furthermore, the retaining element P4 and / or the retaining element P5 can be mobile between a retaining position and a retracted position. In the retaining position, visible to the figure 4 And 5In the extended position, also known as the deployed position, the retaining element is in contact with at least one of the cores. In the retracted position, the retaining element is set back from the cores, its length being shorter than its length in the extended position. The mobility of the retaining element(s) allows for easy demolding of the resulting part. Indeed, when the retaining element, in its extended position, is aligned along an axis different from the demolding axis, its retracted position allows the retaining element to move freely without hindering demolding. The retaining element also includes a retraction mechanism, ensuring mobility between the retracted and extended positions.

[0039] Alternatively, the retaining member P4 and / or the retaining member P5 may further include a spacing means D4, D5 between their first and second support points. The spacing means ensures a constant spacing distance between the first and second support points, the spacing distance being measured, for example, along the axial direction X. More precisely, the spacing means D4, D5 keeps the two cores separated from each other without them being in contact, i.e., without the cores touching. Since the cores extend along the three spatial directions, the spacing distance can be measured along the longitudinal direction Z or the transverse direction Y. A spacing means is, for example, represented by the diameter of the retaining member. The retaining member may, for example, have a constant diameter along its entire length.According to another example, the retaining member may have a smaller diameter towards its free end, and a larger diameter towards its base (i.e. on the side of the first molding face).

[0040] Alternatively, the retaining member P4 and / or the retaining member P5 may further include a means for adjusting the position of the cores in the first molded face. For example, the adjustment means is an eccentric, which can be rotated around the transverse Y direction to offset the two cores in the plane formed by the transverse and axial directions.

[0041] In another alternative, the first molding face 20 may further include counter-supports, as illustrated in the figure 2 It can thus be seen that the first mold face 20 includes, 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 mold face 20 also includes a first counter-support 41f and a second counter-support 42f. The counter-supports contribute to holding the cores in the mold, as well as to the contact of the cores with the support points. For example, as visible in the figure 4 The first counter-support 41a of the leading edge core 22 presses the leading edge core against the retaining member P4. Furthermore, the first counter-support 41f of the trailing edge core 21 presses the trailing edge core 21 against the retaining member P4. Also, as can be seen in the figure 5 The second counter-support 42a of the leading edge core 22 presses the leading edge core against the retaining member P5. Furthermore, the first counter-support 41f of the trailing edge core 21 presses the trailing edge core 21 against the retaining member P5. As also visible on the figures 4 And 5 , the first counter-supports 41a, 41f and respectively the second counter-supports 42a, 42f extend along the axial direction X. In addition, the first counter-supports 41a, 41f and respectively the second counter-supports 42a, 42f can be aligned along the axial direction X with the respective retaining members P4 and P5.

[0042] Alternatively, although not illustrated, the elements described above for the support member P4 can be applied to the support member P5, and conversely, the elements described above for the support member P5 can be applied to the support member P4. For this purpose, the first support member can be the support member P5 and the second support member can be the support member P4. Thus, the first and second support points of the first support member P5 can be points P5a and P5f, respectively, and the first and second support points of the second support member P4 can be points P4a and P4f, respectively.

[0043] We now describe a process for producing a mold of a turbomachine blade from a disposable material, the process comprising: Provide the leading edge core 22 and the trailing edge core 21; provide the injection mold for the disposable material; position the leading edge core 22 and the trailing edge core 21 on the first mold face 20. In this position, the first retaining member has a first bearing point on a first bearing surface of a core element, the first bearing surface extending against the core, for holding said core element in position along the second direction. Furthermore, in this position, the retaining member(s) P4, P5 pass at least partially through the leading edge core 22 and the trailing edge core 21.

[0044] Alternatively, the process may include: closing the mold by positioning the second molding face on the core elements, with at least one additional retaining element.

Claims

1. Assembly for producing a molding, made of removable material, of a turbomachine blade, comprising an injection mold for 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 (22, 21) extending in a first direction (Z), the mold comprising: - a first molding face (20) for molding a pressure-side face of the blade and a second molding face for molding a suction-side face of the blade and arranged facing the first face in a second direction (Y) perpendicular to the first direction (Z), - retaining members (P4, P5) for holding the cores (22, 21) in position in the injection mold, characterized in that at least a first retaining member (P4) extends from the first face of the mold in the second direction and extends at least partially through the first and second core elements (22, 21), the first retaining member (P4) comprising a first support point (P4a) at which it bears against the first core element (22) and a second support point (P4f) at which it bears against the second core element (21).

2. Assembly according to claim 1, wherein the first core element (22) and the second core element (21) are shaped so that the first support point (P4a) of the first retaining member (P4) blocks movement of the first core element (22) in a first directional orientation (F1) along a third direction (X) perpendicular to the first (Z) and second (Y) directions and the second support point (P4f) of the first retaining member (P4) blocks movement of the second core element (21) in a second directional orientation (F2) that is opposite to the first directional orientation (F1) along the third direction (X).

3. Assembly according to claim 1 or 2, wherein a second retaining member (P5) extends from the first molding face (20) in the second direction (Y), the second retaining member (P5) comprising a first support point (P5a) at which it bears against the first core element (22) and a second support point (P5f) at which it bears against the second core element (21), said first support point (P5a) and second point of support (P5f) of the second retaining member (P5) being different from the first support point (P4a) and the second support point (P4f) of the first retaining member (P4).

4. Assembly according to claim 3, wherein the first core element (22) and the second core element (21) are shaped so that the first support point (P5a) of the second retaining member (P5) blocks movement of the first core element (22) in the first directional orientation (F1) along a third direction (X) perpendicular to the first (Z) and second (Y) directions and the second support point (P5f) of the second retaining member (P5) blocks movement of the second core element (21) in a second directional orientation (F2) that is opposite to the first directional orientation (F1) along the third direction (X).

5. Assembly according to claim 4, wherein the second retaining member (P5) comprises a spacing means (D5) between the first support point (P5a) of the second retaining member (P5) and the second support point (P5f) of the second retaining member (P5), the spacing means ensuring, during production of the molding made of removable material, a spacing of a constant distance between said support points (P5a, P5f) along the third direction (X).

6. Assembly according to any one of the preceding claims, wherein the first retaining member (P4) comprises a spacing means (D4) between the first support point (P4a) of the first retaining member (P4) and the second support point (P4f) of the first retaining member (P4), the spacing means (D4) ensuring, during production of the molding made of removable material, a spacing of constant distance between said support points (P4a, P4f) along at least one among the first direction (Z), the second direction (Y), or the third direction (X).

7. Assembly according to any one of the preceding claims, wherein the first retaining member (P4) and / or the second retaining member (P5) is movable between a retaining position for holding at least one core element (22, 21) and a retracted position, the retaining member (P4, P5) comprising a retraction mechanism for positioning the retaining member in the retaining position or in the retracted position.

8. Assembly according to any one of the preceding claims, wherein the first retaining member (P4) and / or the second retaining member (P5) comprises an axis of rotation (R) and a head (31) that is eccentric relative to the axis of rotation (R) and that cooperates with the first core element (22) and the second core element (21).

9. Method for producing a molding, made of removable material, of a turbomachine blade, the method comprising: - providing a first core element (22) and a second core element (21), said core elements (22, 21) extending in a first direction (Z), - providing an injection mold for said removable material; the mold comprising: - a first molding face (20) for molding a pressure-side face of the blade and a second molding face for molding a suction-side face of the blade and arranged facing the first face (20) in a second direction (Y) perpendicular to the first direction (Z), - retaining members (P4, P5) for holding the cores in position in the injection mold, among which at least a first retaining member (P4) extends from the first molding face (20) in the second direction (Y), the method being characterized in that it comprises the step of: positioning the first core element (22) and the second core element (21) on the first molding face (20) such that the first retaining member (P4) extends at least partially through the first and second core elements (22, 21) and comprises a first support point (P4a) at which it bears against the first core element (22) and a second support point (P4f) at which it bears against the second core element (21).

10. Method according to claim 9, the mold further comprising a second retaining member (P5) extending from the first molding face (20) in the second direction (Y), the method comprising the step of: positioning the first core element (22) and the second core element (21) on the first molding face (20) such that the second retaining member (P5) comprises a first support point (P5a) at which it bears against the first core element (22) and a second support point (P5f) at which it bears against the second core element (21).