Assembly for the production of a mold in disposable material for a turbomachine blade

Abstract

Assembly for producing a mold of a turbomachine blade from disposable material, comprising an injection mold for said disposable material, in which a first core element (22) and a second core element (21) are adapted to be mounted in a predetermined molding position, the first and second core elements (21, 22) extending along 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 along a second direction (Y) perpendicular to the first direction (Z), - retaining elements (P1a, P1f, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in position of the cores in the injection mold, characterized in that the first molding face (20) comprises at least one first retaining element (P1a, P1f, P2a, P2f, P3a,P3f) extending from the first molded face (20) along the second direction (Y), said first retaining 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 along the second direction (Y). Abstract figure: Figure 1,

Description

Title of the invention: Assembly for producing a mold of a turbomachine blade in disposable material technical field

[0001] The present disclosure relates to the field of turbomachine blades, in particular to blades obtained by casting a molten alloy in a mold using a disposable material casting technique, such as, for example, lost-wax casting. Prior art

[0002] Traditionally, the lost-wax casting technique begins by creating a model in wax, or any other easily removable material, of the part to be produced; this model includes an internal piece forming a ceramic core that represents the cavities to be created inside the blade. The wax model is then dipped several times 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 the manufacture of the metal part by casting. After checking the internal and external integrity of the shell mold, the next step consists of pouring molten metal, which fills the voids between the inner wall of the shell mold and the core, and then solidifying it. In the field of lost-wax casting, several solidification techniques and several casting techniques are currently distinguished, depending on the nature of the alloy and the expected properties of the resulting casting. These may include directional solidification with a columnar structure (DS), directional solidification with a single-crystal structure (SX), or equiaxed solidification (EX).

[0005] After the alloy is poured, the shell is broken by a shakeout operation. In a subsequent step, the ceramic core that remains trapped within the resulting blade is chemically removed. The resulting 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 patent applications FR2875425 and FR2874186 of the de- manderesse.

[0007] To form the wax model of the blade, 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 formation of more elaborate internal cavities for the circulation of the cooling fluid within these blades. These blades are characterized by having several 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 assembled and glued together. The individual cores are generally joined at their base and top. This allows for control of the thickness of the walls and partitions 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 necessary to position the different parts of the core very precisely relative to each other in the wax injection mold and to ensure 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 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 produce 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 a complex geometry, 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 comprising a conventional six-point isostatic positioning system.

[0012] One difficulty encountered is twofold, as it consists, on the one hand, of very precisely positioning the different parts of the core within 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 have their own conventional six-point isostatic positioning system relative to the mold, as this would double the number of supports to be integrated into the wax injection mold, which in terms The mold dimensions are not feasible. Furthermore, since the two core parts are interlocked at certain points, some isostatic points cannot be placed within the wax injection mold. Consequently, simply positioning the cores relative to the mold does not allow for complete alignment of the cores with each other.

[0013] It is therefore understood 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. Summary

[0015] To this end, the present 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 along 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, - core positioning devices in the injection mold, in which the first mold face includes at least one first holding device extending from the first mold face in the second direction (Y), said first holding device including a first support point on a first support surface of a core element, the first support surface extending against the core element, for holding said core element in position in the second direction.

[0016] Alternatively or additionally, the assembly may comprise the following features, taken alone or in combination: - the first molding face includes three initial retaining members for the first core element and three initial retaining members for the second core element; - each core element extending, along the first direction, between a foot and a head, in which, for each core element, along the first direction, one of the first three support organs is arranged further from the foot than from the head relative to the other two first support organs among the first three support organs; - each core element foot includes a free end, the free ends overlapping by complementary shape, at least partially; - the two other first support elements are arranged near the free end of the feet of the first and second core element; - the first mold face includes at least one second retaining member extending from the first face of the mold, said second retaining member including a second support point on a second support surface of a core element, the second support surface extending perpendicularly to the first direction, for holding said core element in position along the first direction; - the second retaining element of the first core element extends from the first molding face, along the second direction; - the second retaining element of the second core element extends from the first molding face, along the second direction; - the second retaining element of the second core element extends from the first molding face, along a third direction perpendicular to the first and second directions; - The assembly further comprises two additional retaining members, said additional retaining members being common to the first and second core elements, and wherein: - the first three retaining members of the first core element, the second retaining member of the first core element, and the two additional retaining members form a first positioning reference frame for the first core element in the injection mold, and - the first three retaining members of the second core element, the second retaining member of the second core element, and the two additional retaining members form a second positioning reference frame for the second core element in the injection mold.

[0017] According to another aspect, a method is proposed for producing a mold of a turbomachine blade in disposable material, the method comprising: - provide a first kernel element and a second kernel element, said kernel elements extending along a first direction, - provide an injection mold for said disposable material; 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 the cores in the injection mold, among which at least one retaining device extends from the first mold face in the second direction to hold said core element in position in the second direction the process including the step: positioning the first core element and the second core element on the first molding face such that 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 element, for holding said core element in position along the second direction.

[0018] The process described above may further include the step: The mold is closed by positioning the second mold face onto the core elements. This second mold face includes at least one retaining element that complements the first retaining element of the first mold face. Brief description of the drawings

[0019] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which: Fig. 1

[0020] [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 disposable material. Fig. 2

[0021] [Fig.2] shows the view of [Fig.1], without the first and second core elements, the first face of the injection mold including retaining elements with support points for retaining the leading edge and trailing edge cores. Fig. 3

[0022] [Fig.3] shows a view of the leading edge core from its extrados face, on which support points are schematically shown. Fig. 4

[0023] [Fig.4] shows a view of the trailing edge core from its upper surface, on which are schematically represented as support points. Fig. 5

[0024] [Fig.5] is a cross-sectional view of [Fig.1] along axis AA. Fig. 6

[0025] [Fig.6] is a cross-sectional view of [Fig.1] along axis BB. Fig. 7

[0026] [Fig.7] is a cross-sectional view of [Fig.1] along axis BB, illustrating a first example of the construction of a support component. Fig. 8

[0027] [Fig.8] is a cross-sectional view of [Fig.1] along axis BB, illustrating a second example of the realization of a retaining element. Fig. 9

[0028] [Fig.9] is a top view of the example illustrated in [Fig.8]. Description of the implementation methods

[0029] The terms "upstream" and "downstream" are subsequently defined with respect to the direction of gas flow through a turbomachine, indicated by arrow F on [Fig.1].

[0030] Figure 1 illustrates the arrangement of the core elements in an injection mold, with only a 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.

[0031] The cores 21, 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 upper and lower surfaces 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). In [Fig. 1], only the lower surface of the leading edge core 23a and the lower surface of the trailing edge core 23f are visible. The upper surface of the leading edge core 24a and the upper surface of the trailing edge core 24f, visible for each core in Figures 3 and 4, are positioned with respect to the first molding face 20.The leading edge cores 22 and trailing edge cores 21 each comprise a head 25a, 25f 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 core 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 designed to form a blade trough bottom wall in the final blade. With reference to the longitudinal direction Z and [Fig. 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 [Fig. 4], the cutout 27f of the trailing edge core 21 is delimited by an upper cutout wall 27 If and by 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 upstream edge 28 of the trailing edge core and terminates with a longitudinal portion of the cutout 29 which extends longitudinally along the longitudinal direction Z into the core material, and therefore without crossing the core. The core extends to its downstream edge 30. The feet 26a, 26f further include a free end 31a, 3If, corresponding to a non-functional area of ​​the core. The free ends 31a, 3If may overlap, at least partially. For this purpose, the free end 3If of the trailing edge core may include a tab 33f. In addition, 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 fastened together, for example, by drilling through the overlapping portion of material and then inserting an aluminum rod.

[0032] The trailing edge core 21 further comprises a notch 32 on its downstream edge 30. The notch 32 is arranged in the head area 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.

[0033] Figure 2 illustrates the first mold face 20, without the cores 21, 22. The first mold face includes retaining elements Pla, Pif, P2a, P2f, P3a, P3f, P4, P5, P6a, P6f for holding the cores in position within the injection mold. Each retaining element holds the leading edge core 22 or the trailing edge core 21, or both cores 21 and 22, in position along one of the three directions X, Y, or Z. In particular, 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 is formed by the retaining elements Pla, P2a, P3a, P4, P5, and P6a. The second positioning reference frame is formed by the support elements Pif, P2f, P3f, P4, P5 and P6f (or alternatively 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.

[0034] In particular, the retaining elements Pla, Pif, P2a, P2f, P3a, and P3f (or first retaining elements) 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. The retaining elements Pla, P2a, and P3a are designed to hold the leading edge core 22 in position along the transverse Y direction. The retaining elements Pif, P2f, and P3f are designed to hold the trailing edge core 21 in position along the transverse Y direction. Each of the retaining elements Pla, Pif, P2a, P2f, P3a, and P3f extends from the first molding 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.

[0035] In particular, the retaining elements Pla, P2a, P2f, and Pif are arranged in the foot zone 26a, 26f of the cores. These retaining elements Pla, P2a, P2f, and Pif are aligned along the axial direction X. The retaining elements Pla, P2a, P2f, and Pif are arranged near the free end 31a, 31f of the cores. In other words, the retaining elements Pla, P2a, P2f, and Pif are arranged outside the free end of the cores, but within the foot zone 26a, 26f of the cores. The retaining elements Pla, P2a, P2f, and Pif terminate in a bearing surface for the respective core, each of these bearing surfaces being substantially planar. Furthermore, each of these bearing surfaces is substantially perpendicular to the transverse direction Y. These surfaces are also located outside the functional zone.

[0036] The retaining elements P3a and P3f are arranged in the head zone 26a, 26f of the cores. The retaining element P3a and the retaining element P3f are offset along the longitudinal direction Z. In other words, the retaining elements P3a and P3f are not aligned along the axial direction X. The 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 contact zone. In other words, for optimal retention, the bearing surfaces of the retaining elements P3a and P3f conform to the shape of the surface of the core zone with which they are in contact.

[0037] Alternatively and in addition, the second molding face may include retaining members similar to the retaining members described above, so as to lock the cores in position along the transverse direction Y.

[0038] The first mold face 20 may further include retaining elements P6a and P6f (or a second retaining element). 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.The retaining member P6f is designed, for example, to hold 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.

[0039] Alternatively, a retaining member P6'f may be provided instead of the retaining member P6f. The retaining member P6'f is provided for holding in the following position the longitudinal direction Z of the trailing edge core 21. The retaining member P6'f extends from the first molding 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.

[0040] 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 direction Z. 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 expansion of the two cores during the alloy casting process.

[0041] Indeed, the retaining element P6 distributes the expansion of the trailing edge core 21 in the longitudinal direction Z, towards the tip 25f and towards the root 26f, preventing an excessive length difference with the leading edge core 22, particularly in cases of very different expansions 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 of 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, that is, 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 height of the wall be as small as possible, so as to minimize a significant difference in level between the parts of the tub bottom. Consequently, 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 obtaining two tub bottom parts that are essentially in the same plane perpendicular to the longitudinal direction Z.

[0042] The first molded face further includes the retaining members P4 and P5 (or additional retaining members). The retaining members P4 and P5 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 axial direction X. The retaining members P4 and P5 are common retaining members for both leading edge cores 22 and Trailing edge 21. The retaining elements P4 and P5 each comprise a first bearing point on the leading edge core and a second bearing point on the trailing edge core. The retaining elements P4 and P5 together prevent the rotation of the cores around the transverse Y axis. Each of the retaining elements P4 and P5 extends from the first molding face, along the transverse Y direction.

[0043] Figures 7 and 8 illustrate examples of embodiments of a retaining member in a cross-sectional view along the axial direction X. Figure 9 is a top view of the example in Figure 8. These embodiments can be applied, for example, 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 Figure 7, the head 31 is aligned with the axis of rotation R.Therefore, the rotation of the base 30, the retaining member, around the axis of rotation R does not cause any displacement of the head 31, i.e., no 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, in this example, has 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 to adjust their position in the mold, the leading edge core 22 and trailing edge core 21 cooperating with the retaining member, as detailed later in this text. .

[0044] The retaining member P4 can be arranged in the head area 25a, 25f. The retaining member P5 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 also arranged in a non-functional area, i.e., outside the part.

[0045] The retaining member P4 is visible in [Fig. 5], corresponding to a cross-sectional view along axis AA of [Fig. 1]. It can be seen that the retaining 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 that the leading edge core 22 is locked in a direction Fl from upstream to downstream. Similarly, the second support point P4f ensures that the trailing edge core is locked in a direction F2 from downstream to upstream, that is to say, in the opposite direction to the locking direction of the leading edge core. The retaining member 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.

[0046] The retaining member P5 is visible in [Fig. 6], corresponding to a cross-sectional view along axis BB of [Fig. 1]. It can be seen that the retaining member 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 member P5a ensures that the leading edge core 22 is held in place in a direction Fl from upstream to downstream. Similarly, the second bearing point of the retaining member P5f ensures that the trailing edge core 21 is held in place in a direction F2 from downstream to upstream, that is to say, in the opposite direction to the direction Fl of the leading edge core being held. The retaining member 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, the extrados face 24a, 24f of the cores. However, as shown in [Fig. 6], the retaining element P5 traverses, along the transverse direction Y, only an alignment defined by the extrados faces 24a, 24f of the two cores, without passing through the cores themselves. In other words, the retaining element P5 is positioned between the two cores and extends beyond their extrados face 24a, 24f, but not beyond their intrados face 23a, 23f. Alternatively, the P5 retaining organ can extend beyond their intrados face 23a, 23f.

[0047] Furthermore, the retaining member P4 and / or the retaining member P5 can be mobile between a holding position and a retracted position. In the holding position, visible in [Fig. 4] and 5, which can also be called the deployed position, the retaining member is in contact with at least one of the cores. In the retracted position, the retaining member is set back from the cores, its length being less than its length in the holding position. The mobility of the retaining member(s) allows for easy demolding of the resulting part. Indeed, when the retaining member, in its deployed position, is arranged along an axis different from the demolding axis, its retracted position allows the retaining member not to impede demolding. The retaining member also includes a retraction mechanism, ensuring mobility between the retracted position and the holding position.

[0048] Alternatively, the retaining member P4 and / or the retaining member P5 may further comprise a spacing means D4, D5 between their first and second support points. The spacing means ensures a spacing (or separation) of a constant 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 maintains the two cores apart, 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 Z direction or the transverse Y direction. A spacing means is, for example, represented by the diameter of the retaining element. The retaining element may, for example, have a constant diameter along its entire length. As another example, the retaining element may have a smaller diameter at its free end and a larger diameter at its base (i.e., on the side of the first molded face).

[0049] 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 about the transverse direction Y to offset the two cores in the plane formed by the transverse and axial directions.

[0050] In another alternative, the first mold face 20 may further include counter-supports, as illustrated in [Fig. 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 retaining the cores in the mold, as well as to the contact of the cores with the support points. For example, as shown in [Fig. 4], the first counter-support 41a of the leading edge core 22 presses the leading edge core against the retaining member P4. In addition, 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 [Fig.[5] The second counter-support 42a of the leading edge core 22 presses the leading edge core against the retaining member P5. In addition, 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 in Figures 4 and 5, the first counter-supports 41a, 41f and respectively the second counter-supports 42a, 42f extend along the axial direction X. Furthermore, 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.

[0051] A method for producing a mold of a turbomachine blade from a disposable material is now described, the method 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 molded face 20. In this position, the first retaining member presents a first point of support 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 penetrate at least partially through the leading edge core(s) 22 and trailing edge core(s) 21.

[0052] Alternatively, the method may include: closing the mold by positioning the second molding face on the core elements, with at least one additional retaining member.

Claims

Demands

1. An assembly for producing a mold of a turbomachine blade from disposable material, comprising an injection mold for said disposable material in which a first core element (22) and a second core element (21) are adapted to be mounted in a predetermined molding position, the first and second core elements (21, 22) extending along 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 along a second direction (Y) perpendicular to the first direction (Z), - retaining elements (Pla, Pif, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in position of the cores in the injection mold, the first molding face (20) comprising at least one first retaining element maintenance (Pla, Pif, P2a, P2f, P3a,P3f) extending from the first molding face (20) along the second direction (Y), said first retaining member (Pla, Pif, P2a, P2f, P3a, P3f) comprising a first support 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 along the second direction (Y) characterized in that the first molding face (20) comprises three first retaining members (Pla, P2a, P3a) for the first core element (22) and three first retaining members (Pif, P2f, P3f) for the second core element (21).

2. Assembly according to claim 1, each core element (21, 22) extending, along the first direction (Z), between a foot (26f, 26a) and a head (25f, 25a), wherein, for each core element (21, 22), along the first direction (Z), one of the first three retaining members (P3f, P3a) is arranged further from the foot (26f, 26a) than from the head (25f, 25a) relative to the other two first retaining members (Pif, Pla, P2f, P2a) of the first three retaining members (Pla, Pif, P2a, P2f, P3a, P3f).

3. Assembly according to claim 2, wherein each foot (26a, 26f) of core element (22, 21) comprises a free end (31a, 31f), the free ends (31a, 31f) overlapping by complementarity of form, at least partially.

4. Assembly according to claim 3, wherein the two other first retaining members (Pif, P1a, P2f, P2a) are arranged near the free end (31a, 3If) of the feet (26a, 26f) of the first and second core element (22, 21).

5. Assembly according to any one of the preceding claims, wherein the first mold face (20) comprises at least one second retaining member (P6a, P6f, P6'f) extending from the first mold face (20), said second retaining member (P6a, P6f, P6'f) comprising a second bearing point on a second bearing surface of a core element (22, 21), the second bearing surface extending perpendicularly to the first direction, for holding said core element (22, 21) in position along the first direction (Z).

6. Assembly according to claim 5, wherein the second retaining member of the first core element (P6a) extends from the first molding face (20), along the second direction (Y).

7. Assembly according to claim 5 or 6, wherein the second retaining member of the second core element (P6'f) extends from the first molding face (20), along the second direction (Y).

8. Assembly according to claim 5 or 6, wherein the second retaining member of the second core element (P6f) extends from the first molding face (20), along a third direction (X) perpendicular to the first (Z) and the second direction (Y).

9. Assembly according to any one of claims 5 to 8, further comprising two additional retaining members (P4, P5), said additional retaining members (P4, P5) being common to the first and second core element (22, 21), and wherein: - the first three retaining members (Pla, P2a, P3a) of the first core element (22), the second retaining member of the first core element (P6a) and the two additional retaining members (P4, P5) form a first positioning reference frame of the first core element (22) in the injection mold, and - the first three retaining members (Pif, P2f, P3f) of the second core element (21), the second retaining member of the second core element (P6f, P6f') and the two additional retaining members (P4, P5) form a second positioning reference frame of the second core element (21) in the injection mold.

10. A method for producing a mold of a turbomachine blade from disposable material, the method comprising: - providing a first core element (22) and a second core element (21), said core elements extending along a first direction (Z), - providing an injection mold for said disposable material; the mold comprising: - a first face for molding (20) of an intrados face of the blade and a second face for molding an extrados face of the blade arranged opposite the first face along a second direction (Y) perpendicular to the first direction (Z), - retaining members (Pla, Pif, P2a, P2f, P3a, P3f, P6a, P6f, P6'f) in position of the cores in the injection mold, among which at least one first retaining member (Pla, Pif, P2a, P2f, P3a, P3f) extends from the first molding face (20) along the second direction (Y) for retaining said core element in position along the second direction (Y), - positioning the first core element (22) and the second core element (21) on the first molding face (20) such that the first retaining member (Pla, Pif, P2a, P2f, P3a, P3f) has a first point of contact on a first bearing surface of a core element (22, 21), the first bearing surface extending against the core element (21, 22), for holding said core element (22, 21) in position along the second direction (Y), the method being characterized in that it comprises the step: closing the mold by positioning the second molding face on the core elements (21, 22), the second molding face comprising at least one retaining member complementary to the first retaining member (Pla, Pif, P2a, P2f, P3a, P3f, P6a, P6f) of the first face molding (20).

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