PROCESS FOR MANUFACTURING TURBOMACHINE BLADES

Abstract

A method (100) for manufacturing turbomachine blades, the manufacturing method (100) comprising the steps of: providing a tubular part (20) extending along a first axis (A1) between a first (22) end and a second end (24); machining the tubular part (20) to produce a plurality of blade blanks (10), each blade blank (10) comprising a core (16) extending along a longitudinal axis (X) between a first end portion (12; 14) and a second end portion (12; 14); machining the first end portion (12; 14) and / or the second end portion (12; 14) of each blade blank (10) to produce a reference element; separating the blade blanks (10) from each other. Abstract figure: Figure 4

Description

Title of the invention: METHOD FOR MANUFACTURING TURBOMACHINE BLADES Technical field

[0001] The present description relates to a method of manufacturing turbomachine blades. Prior art

[0002] To manufacture turbomachine blades, a blade blank 11 is generally first produced that approximates the final profile of the blade. As can be seen in [Fig. 1], the blade blank 10 of a turbomachine blade conventionally comprises a root 12, a heel 14 and a core 16 extending between the root 12 and the heel 14. It is known, to obtain such a blank 10, to machine from the mass a bar 11 of elongated cylindrical or conical shape. Such a bar 11 is shown in [Fig. 2]. Such an approach is particularly suitable for producing blades made of titanium aluminide (TiAl). Indeed, TiAl blades advantageously have good mechanical strength at high temperatures and a low density, but foundry processes do not allow the production of foundry blanks of TiAl parts with a complex geometry such as a blade.

[0003] However, a bar 11 contains a single blade blank 10 or, at most, two blade blanks 10 arranged in an interlocking manner in the mass of the bar 11. Therefore, the known method does not allow the operations for obtaining a blank to be pooled for a large number of parts.

[0004] Furthermore, the method of machining a bar 11 from the mass to obtain a blank is generally carried out by water jet cutting so as, on the one hand, to isolate each blade blank if the bar 11 is adapted to form two blade blanks 10 and, on the other hand, to make preliminary cuts over significant thicknesses to obtain the blank 10 as such. However, the blanks obtained by water jet cutting have faces, in particular at the heel 14 and the root 12, the surface condition, roughness and flatness of which are not suitable for positioning the blank in a machine tool, nor for taking a 6-point reference during the following operations necessary for manufacturing the blade.It is in fact necessary to carry out, independently for each blade blank 10, an intermediate reference taking and intermediate operations to recondition the faces of the blade blank 10 at the root 12 and the heel 14. Thus, such a method of manufacturing blade blanks 10 has the disadvantage of being long and expensive due to a large number of successive operations. Summary

[0005] A method of manufacturing turbomachine blades is provided, the manufacturing method comprising the steps: - providing a tubular part extending along a first axis between a first end and a second end, - machining the tubular part to produce a plurality of blade blanks, each blade blank comprising a core extending along a longitudinal axis between a first end portion and a second end portion, - machining the first end portion and / or the second end portion of each blade blank to produce a reference element, - separate the blade blanks from each other.

[0006] Such a method makes it possible to pool the operations for producing blade blanks for a large number of blades. Furthermore, the method allows the production of a unitary reference element for each blade blank. The reference element of each blade blank is adapted for isostatically positioning the blade blank in a machine tool and / or allows a 6-point reference point on the respective blade blank during subsequent operations to obtain the final profile of the blade to be manufactured. This guarantees the reproducibility of the blades manufactured from the blade blanks obtained by this method, in particular by avoiding additional operations for reconditioning the end parts of each blade blank. The time required to implement such a method for manufacturing turbomachine blades and the associated costs are consequently reduced.

[0007] The first end portion of each blade blank may form a root of the blade blank in question. The root of the blade blank may be machined so as to extend radially relative to the first axis. The second end portion of each blade blank may form a heel of the blade blank in question. The core of each blade blank is intended to form the blade of the corresponding blade after machining.

[0008] By "tubular part" is meant a part having a section normal to the first axis which is annular around the first axis. The plurality of blade blanks is machined in the thickness of the wall of the tubular part.

[0009] The production of a reference element on the first end portion and / or the second end portion of each blade blank may comprise the machining of at least one face of the end portion considered of each blade blank to produce a reference surface.

[0010] The production of a reference element on the first end portion and / or the second end portion of each blade blank may comprise a groove on the end portion considered of each blade blank.

[0011] The grooving on the first end portion and / or the second end portion of each blade blank may comprise producing a groove on the relevant end portion of each blade blank. Each groove may be machined on the relevant end portion of one of the blade blanks so as to extend annularly around the longitudinal axis of the corresponding blade blank to approximate the corresponding blade blank as closely as possible.

[0012] The longitudinal axis of each blade blank may extend parallel to the first axis of the tubular part.

[0013] The machining of the plurality of blade blanks can be carried out by turning. The turning method for machining the plurality of blade blanks has the advantage of being more economical and more efficient than other conventional machining methods.

[0014] The machining limit of each blade blank can be defined by an excess thickness of between 0.5 mm and 3 mm relative to the final profile of the turbomachine blade to be manufactured. Each blade blank therefore has a profile approaching the final profile of the blade to be manufactured.

[0015] Turning operations can be carried out on a horizontal, vertical or combined (i.e. horizontal and vertical) lathe.

[0016] Several turning strategies can be used, including facing, turning, plunging, boring. Depending on the desired degree of finish, cutting speeds in turning can be between 20 m.min-1 and 1000 m.min-1. Depending on the desired degree of finish, feed rates in turning can be between 0.02 mm.rev-1 and 10 mm.rev-1.

[0017] The machining of a reference element on the first end portion and / or on the second end portion of each blade blank can be carried out by milling.

[0018] Milling operations can be carried out with mobile tools along 3, 4 or 5 axes.

[0019] Several milling strategies can be used, including end milling, roll milling, facing, grooving, contouring, drilling, sweeping. Depending on the desired degree of finish, milling cutting speeds can be between 10 m.min-1 and 500 m.min-1. Depending on the desired degree of finish, milling feed rates can be between 0.001 mm.rev-1 and 1 mm.rev-1.

[0020] Any type of conventional milling tooling may be used. The milling tooling may be selected from a face milling cutter, a cylindrical end mill, a toric end mill, a hemispherical end mill, a form milling cutter, and a drill.

[0021] Milling and / or turning cutting tools can be made of carbide, ceramic, polycrystalline diamond (PCD) or cubic boron nitride material. polycrystalline (CBN).

[0022] The milling and / or turning operations may include lubrication, in particular having as specificity one or more of the following characteristics: soluble oil cooling, neat oil cooling, high pressure cooling, micro-spraying, CO2 lubrication, supercritical CO2 lubrication, air blowing, refrigerated air blowing, nitrogen cryogenics.

[0023] The separation of the blade blanks can be carried out by water jet cutting.

[0024] Water jet cutting operations can be performed with a tool movable along 2 to 6 axes. Waterjet cutting operations can be carried out using several cutting nozzles operating simultaneously and / or independently of each other. Between 1 and 12 cutting nozzles can be provided. Alternatively, as many cutting nozzles as there are blade blanks machined in the tubular part can be provided.

[0025] The pressure of the water jet may be between 2000 bars and 8000 bars. The cutting speed for water jet cutting operations may be between 1 mm. min-1 and 1000 mm.min-1.

[0026] Alternatively, the separation of the blade blanks from each other can be achieved by sawing, cutting, wire cutting or milling.

[0027] Alternatively, the separation of the blade blanks from one another can be carried out by groups of blade blanks, each group of blade blanks comprising at least 2 blade blanks.

[0028] The machining of the plurality of blade blanks and the machining of a reference element on the first end portion and / or the second end portion of each blade blank can be carried out on a single machine tool. In addition, the separation of the blade blanks from the others can be carried out on the same machine tool as that used for the machining of the plurality of blade blanks and the machining of a reference element on the first end portion and / or the second end portion of each blade blank. This minimizes the number of operations for disassembling and positioning the tubular part. This reduces the manufacturing time and manufacturing costs.

[0029] The tubular part may be held during the machining of the plurality of blade blanks and / or during the machining of a reference element on the first end portion and / or on the second end portion of each blade blank. The tubular part may be held by any conventional clamping solutions. For example, the tubular part may be held on a plate, the first axis of the tubular part extending perpendicular to the plate. The plate may comprise a plurality of pairs of jaws adapted to be arranged circumferentially around the first axis of the tubular part. The jaws of each pair of jaws may slide radially relative to the first axis of the tubular part to grip the tubular part on each side in the radial direction relative to the first axis. The plate may comprise a pair of jaws gripping each blade blank.

[0030] The tubular part can be clamped in the direction of the first axis between two plates extending perpendicular to the first axis when separating the blade blanks from each other. Each blade blank is thus held after being separated from the other blade blanks. Each end face of the tubular part in the direction of the first axis can therefore be supported on a respective plate in the direction of the first axis.

[0031] The separation of the blade blanks may comprise the sectorization of the tubular part around the first axis by cuts along a cutting plane which passes circumferentially between two first end portions of two circumferentially consecutive blade blanks around the first axis and said two second end portions of said two consecutive blade blanks.

[0032] The production of each blade blank may include the following sub-steps: - hold the tubular part at the first end, the second end remaining free, - machining the second end of the tubular part so as to produce a plurality of circumferentially distinct second end portions, each corresponding to a blade blank, - machining the tubular part between the first end and the second end so as to produce an internal annular surface and an external annular surface, the core of each blade blank being arranged between the internal annular surface and the external annular surface.

[0033] The production of each blade blank may further comprise the sub-steps: - holding the tubular part at the second end, the first end having remained free - machining the first end of the tubular part so as to produce a plurality of circumferentially distinct first end portions, each being associated with a blade blank.

[0034] Such a method makes it possible to obtain the plurality of blade blanks from a tubular part having the minimum excess material relative to the quantity of material required to form the plurality of blade blanks. In other words, the tubular part can thus be optimized to have a shape as close as possible to the plurality of blade blanks to be manufactured. Milling is thus improved and the quantity of wasted material is reduced. The number of machining operations to obtain the plurality of blade blanks is also reduced. As a result, the costs associated with obtaining the plurality of blade blanks are reduced.

[0035] The first end portion of each blade blank may be located at a portion of the tubular member that includes the first end of the tubular member. The second end portion of each blade blank may be located at a portion of the tubular member that includes the second end of the tubular member.

[0036] The tubular part may be turned over before being held at the second end and an angular indexing appendage about the first axis may be made on the tubular part before the tubular part is turned over. Such an indexing appendage allows angular location of the tubular part about the first axis after being turned over. This allows reference to be taken on the tubular part for subsequent machining operations. The indexing appendage may be a hole made in an end face at the first end or the second end of the tubular part. The indexing appendage may be circumferentially about the first axis between two circumferentially consecutive blade blanks so as not to alter the geometry of one of the blade blanks.

[0037] The tubular part can be held by resting on a horizontal plate, i.e. normal to the gravitational field, with the first axis of the tubular part extending perpendicular to the horizontal plate. Thus the forces or moments induced by the weight of the tubular part are reduced.

[0038] When the tubular part is held at the first end, the end face at the second end of the tubular part may be machined to form a reference plane. The end face at the second end of the tubular part may thus be used as a laying plane when the tubular part is held at the second end. The end face at the second end of the tubular part may be normal to the first axis. The machining of the end face of the second end of the tubular part may be carried out by dressing, i.e. by a machining operation in which the end face of the tubular part is perpendicular to the axis of a machining spindle.

[0039] The tubular part may comprise a non-functional portion at the first end, the tubular part being held at the non-functional portion, the first end portion of each blade blank being arranged between the inner annular surface and the outer annular surface. Such a method makes it possible to completely machine each blade blank without having to change the holding area of ​​the tubular part. The number of operations to obtain the plurality of blade blanks is further reduced. As a result, the costs associated with obtaining the plurality of blade blanks are reduced.

[0040] The term "non-functional" used in reference to the non-functional part of the tubular part makes it possible to indicate that the part thus qualified is not intended to be machined for the production of all or part of a blade blank.

[0041] The tubular part may be held at the first end and after machining the second end portion of each blade blank, the second end portion of each blade blank is machined to produce the associated reference element, and / or wherein when the tubular part is held in position at the second end and after machining the first end portion of each blade blank, the first end portion of each blade blank is machined to produce the associated reference element.

[0042] The reference element machined on the second end portion of each blade blank can be used for isostatic positioning at the second end of the tubular part and for reference taking on the tubular part for machining the tubular part at the first end.

[0043] The functional part can be cut from the rest of the tubular part before separating the blade blanks from each other.

[0044] The tubular part may have a cylindrical shape of revolution around the first axis or a truncated cone shape of revolution around the first axis. The tubular part of conical shape of revolution around the first axis also makes it possible to reduce the quantity of excess material in the tubular part compared to the quantity of material necessary to form the plurality of blade blanks. The conical shape of revolution around the first axis therefore makes it possible to improve the milling and to reduce the quantity of wasted material. Furthermore, such a shape of the tubular part makes it possible to reduce the dimension of the tubular part in the radial direction relative to the first axis. Thus, the separation of the blade blanks from the others is easier and therefore faster.

[0045] The blade blanks can be arranged circumferentially one after the other around the first axis.

[0046] The plurality of blade blanks may be made in pairs of blade blanks, the pairs of blade blanks being arranged circumferentially one after the other around the first axis, the blade blanks of each pair being nested with each other. Such a feature makes it possible to increase the number of blade blanks contained in the tubular part. The blade blanks of each pair may be oriented in opposite directions along the first axis.

[0047] The number of blade blanks machined in the tubular part can be between 10 and 100. The production of the plurality of blade blanks from a tubular part therefore makes it possible to pool the operations of obtaining a large number of blade blanks, unlike a bar of the state of the art from which only 2 blade blanks can be obtained.

[0048] The tubular part can be made of titanium aluminide. The blades thus fa bricks advantageously have good mechanical resistance at high temperature and a low density. Brief description of the drawings

[0049] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0050] [Fig-1] represents a blank of blade intended for the manufacture of a turbine blade- bomachine;

[0051] [Fig.2] represents a bar of the state of the art for manufacturing the blade blank of [Fig.l];

[0052] [Fig.3] is a functional diagram of a method of manufacturing turbomachine blades according to the present description;

[0053] [Fig.4] schematically represents in perspective different successive stages of the process of [Fig.3];

[0054] [Fig.5] is a functional diagram of a first embodiment of a sub-process implemented during a step of the method of [Fig.3];

[0055] [Fig.6] schematically represents in section different configurations of a tubular part for the sub-process of [Fig.5];

[0056] [Fig.7] schematically represents in section a series of steps of the sub-process of [Fig.5];

[0057] [Fig.8] schematically represents a first particular step of the sub-process of [Fig.5];

[0058] [Fig.9] schematically represents a second particular step of the sub-process of [Fig.5];

[0059] [Fig. 10] represents in perspective a tool for holding the tubular part of [Fig.4] in the process of [Fig.5];

[0060] [Fig. 11] is a functional diagram of a second embodiment of a sub-process implemented during a step of the method of [Fig.3];

[0061] [Fig. 12] schematically represents in section different configurations of a tubular part for the sub-process of [Fig. 11];

[0062] [Fig. 13] schematically represents in section a series of steps of the sub-process of [Fig. 11];

[0063] [Fig. 14] includes Fig. 14a and Fig. 14b which each schematically represent a configuration for positioning blade blanks in the tubular part of [Fig.4]. Description of the embodiments

[0064] Reference is now made to [Fig. 3] and [Fig. 4]. [Fig. 3] is a functional diagram of a method for manufacturing turbomachine blades.

[0065] The manufacturing method 100 comprises a first step 110 shown in sub-figure 4a. The first step 110 comprises the provision of a tubular part 20 extending along a first axis A1 between a first end 22 and a second end 24. The tubular part 20 has a section normal to the first axis A1 which is annular around the first axis A1. The tubular part 20 has an end face at each end which is here normal to the first axis A1. The tubular part 20 can be obtained from centrifugal casting. The tubular part 20 can be made of titanium aluminide (TiAl). The turbomachine blades obtained from the tubular part 20 can thus be made of TiAl so as to advantageously have good mechanical strength at high temperature and a low density.

[0066] The manufacturing method 100 comprises a second step 120, shown in sub-figure 4b. The second step 120 comprises the machining of a plurality of blade blanks 10 from the tubular part 20. Such machining makes it possible to pool the operations of producing blade blanks 10 for a large number of blades to be manufactured. Each blade blank 10 comprises a core 16 extending along a longitudinal axis X between a root 12 and a heel 14. The core 16 of each blade blank 10 is intended to form the blade of the corresponding blade after machining. The plurality of blade blanks 10 is machined in the thickness of the wall of the tubular part 20. The longitudinal axis X of each blade blank 10 extends here parallel to the first axis A1 of the tubular part 20.As can be seen in Figure 14b, the blade blanks 10 are arranged in the tubular part 20 circumferentially one after the other around the first axis AL. The tubular part 20 may have dimensions suitable for machining between 10 and 100 blade blanks 10.

[0067] Alternatively, as visible in Figure 14a, the blade blanks 10 can be produced in pairs 33 of blade blanks 10, the pairs 33 of blade blanks 10 being arranged circumferentially one after the other around the first axis AL. The blade blanks 10 of each pair 33 are nested with each other. The blade blanks 10 of each pair 33 are in particular oriented in opposite directions along the first axis AL. This makes it possible to further increase the number of blade blanks 10 contained in the tubular part 20. Also visible in [Fig. 14], each blade blank 10 can be arranged in the tubular part 20 so that the root 12 and the heel 14 extend generally in the circumferential direction around the first axis Al (figure 14b) or so that the root 12 and the heel 14 extend generally in a respective radial direction relative to the first axis Al (figure 14a).

[0068] The second step 120 of the manufacturing method 100 further comprises the machining of the root 12 and the heel 14 of each blade blank 10 to produce a blade element. reference element associated respectively with the root 12 and the heel 14 of each blade blank 10. The reference element at the root 12 and the heel 14 of each blade blank 10 is adapted for placing the blade blank 10 in isostatic position in a machine tool and / or allows a 6-point reference taking on the respective blade blank 10 during subsequent operations to obtain the final profile 19 of the blade to be manufactured. This guarantees the reproducibility of the blades manufactured from the blade blanks 10 obtained by the manufacturing method 100, in particular by avoiding additional operations of reconditioning the root 12 and the heel 14 of each blade blank 10.

[0069] [Fig.5] is a functional diagram of a first embodiment of a sub-process 200 implemented during the second step 120 of the manufacturing method 100. [Fig.7] schematically represents the sub-process 200 according to the first embodiment.

[0070] As shown in transparency in [Fig.6], in the first embodiment of the sub-process 200 which is implemented during the second step 120 of the manufacturing method 100, the tubular part 20 is such that the root 12 of each blade blank 10 is located at a portion of the tubular part 20 which comprises the first end 22 of the tubular part 20 and the heel 14 of each blade blank 10 is located at a portion of the tubular part 20 which comprises the second end 24 of the tubular part 20.

[0071] As visible in sub-figure 6a, the tubular part 20 may have a cylindrical shape of revolution around the first axis AL. Alternatively, as shown in sub-figure 6b, the tubular part 20 may have a frustoconical shape of revolution around the first axis AL. In the remainder of the description, the sub-process 200 according to the first embodiment is described with reference to figures 5 to 8 in which the tubular part 20 is shown having a cylindrical shape of revolution around the first axis AL.

[0072] The sub-method 200 according to the first embodiment comprises a first sub-step 210 shown in sub-figure 7a. The first sub-step 210 comprises holding the tubular part 20 at the first end 22 of the tubular part 20. Remarkably, the second end 24 of the tubular part 20 remains free.

[0073] The tubular part 20 can be held on a first plate 30 visible in [Fig. 10]. The tubular part 20 is arranged on the first plate 30 so that the first axis A1 of the tubular part 20 extends perpendicular to the first plate 30. The first plate 30 here comprises a plurality of pairs 33 of jaws 32 adapted to be arranged circumferentially around the first axis A1 of the tubular part 20. The jaws 32 of each pair 33 of jaws 32 can slide ra- dially relative to the first axis A1 of the tubular part 20 to grip the tubular part 20 on each side in the radial direction relative to the first axis A1. The first plate 30 may in particular comprise a pair 33 of jaws 32 gripping each blade blank 10. The tubular part 20 is here held by being supported on the first plate 30 with that being arranged horizontally, i.e. normal to the gravity field. Thus the forces or moments induced by the weight of the tubular part 20 are reduced.

[0074] The sub-process 200 according to the first embodiment comprises a second sub-step 220 shown in sub-figure 7b. The second sub-step 220 comprises the machining of the end face at the second end 24 of the tubular part 20 so as to form a reference plane. The reference plane is normal to the first axis AL. Furthermore, the machining of the end face at the second end 24 of the tubular part 20 makes it possible to produce an end face of the heel 14 of each blade blank 10. The machining of the end face at the second end 24 of the tubular part 20 is carried out by turning. In particular, the machining of the end face of the second end 24 of the tubular part 20 is carried out here by dressing, i.e. by a machining operation in which the end face of the tubular part 20 is perpendicular to the axis of a machining spindle.

[0075] The sub-process 200 according to the first embodiment comprises a third sub-step 230 shown in sub-figure 7c and in [Fig.8]. The third sub-step 230 firstly comprises machining the second end 24 of the tubular part 20 so as to produce a plurality of circumferentially distinct heels 14, each corresponding to a blade blank 10. The third sub-step 230 further comprises machining the tubular part 20 between the first end 22 and the second end 24 so as to produce an inner annular surface 26 and an outer annular surface 28, the core 16 of each blade blank 10 being arranged between the inner annular surface 26 and the outer annular surface 28.

[0076] The machining carried out during the third sub-step 230 is here carried out by turning. The turning method has the advantage of being more economical and more efficient than other conventional machining methods. The limit of the machining by turning is defined by an excess thickness of between 0.5 mm and 3 mm of each blade blank 10 relative to the final profile 19 of the corresponding turbomachine blade to be manufactured. In the example illustrated, the turning operations are carried out on a vertical lathe, i.e. the tubular part 20 is rotated about the first axis A1, the latter being aligned with the gravity field. Several turning strategies are used, in particular facing, turning, plunging, boring. Depending on the desired degree of finish, the cutting speeds in turning can be between 20 m.min 1 and 1000 m.min *. Depending on the desired degree of finish, the feed rates in turning can be between 0.02 mm.tr1 and 10 mm.tr1.

[0077] The sub-process 200 according to the first embodiment comprises a fourth sub-step 240 shown in sub-figure 7d. The fourth sub-step 240 is carried out when the tubular part 20 is held at the first end 22 and after having machined at least the heel 14 of each blade blank 10. The fourth sub-step 240 comprises the machining of the heel 14 of each blade blank 10 to produce the associated reference element.

[0078] The production of a reference element on the heel 14 of each blade blank 10 here comprises the machining of each of the faces 15 of the heel 14 of each blade blank 10 to produce reference surfaces on the heel 14 of each blade blank 10.

[0079] The machining carried out during the fourth sub-step 240 is here carried out by milling. Several milling strategies are used here, in particular surfacing and contouring. Depending on the desired degree of finish, the milling cutting speeds can be between 10 m.min 1 and 500 m.min *. Depending on the desired degree of finish, the milling feed rates can be between 0.001 mm.tr 1 and 1 mm.tr 1.

[0080] The turning operations and the milling operations are here carried out on the same machine tool.

[0081] The sub-method 200 according to the first embodiment comprises a fifth sub-step 250 shown in sub-figure 7e. The fifth sub-step 250 comprises the production of an angular indexing appendage 25 around the first axis A1 is produced on the tubular part 20. The indexing appendage 25 is produced in the form of a hole in the end face at the level of the second end 24 of the tubular part 20. The hole 25 is produced circumferentially around the first axis A1 between two circumferentially consecutive blade blanks 10 so as not to alter the geometry of one of the blade blanks 10. Such an indexing appendage 25 allows angular location of the tubular part 20 around the first axis A1 after having been turned over.

[0082] The sub-process 200 according to the first embodiment comprises a sixth sub-step 260 shown in sub-figure 6f. The sixth sub-step 260 comprises turning the tubular part 20 over and holding the tubular part 20 at the second end 24 on the first plate 30. Remarkably, the first end 22 of the tubular part 20 remains free. The indexing appendage 25 allows a reference to be taken on the tubular part 20 to carry out the following sub-steps. Also, the end face at the second end 24 of the tubular part 20, previously machined during the second sub-step 220, can be used as a laying plane when the tubular part 20 is held at the second end 24. Alternatively or in addition, the reference element machined on the heel 14 of each blade blank 10 can be used for isostatic positioning at the second end 24 of the tubular part 20 and for taking reference on the tubular part 20 for machining the tubular part 20 at the first end 22.

[0083] The sub-process 200 according to the first embodiment comprises a seventh sub-step 270 shown in sub-figure 7g. The seventh sub-step 270 comprises the machining of the end face at the first end 22 of the tubular part 20. This makes it possible to produce an end face of the root 12 of each blade blank 10. The machining of the end face of the second end 24 of the tubular part 20 is here carried out by turning, in particular by dressing.

[0084] The sub-process 200 according to the first embodiment comprises an eighth sub-step 280 shown in sub-figure 7h. The eighth sub-step 280 comprises machining the first end 22 of the tubular part 20 so as to produce a plurality of circumferentially distinct heels 14, each corresponding to a blade blank 10. The machining carried out during the eighth sub-step 280 is here carried out by turning according to characteristics identical to those described with reference to the third sub-step 230.

[0085] The sub-process 200 according to the first embodiment comprises a ninth sub-step 290 shown in sub-figure 7i. The ninth sub-step 290 is carried out when the tubular part 20 is held at the second end 24 and after having machined the root 12 of each blade blank 10. The ninth sub-step 290 comprises the machining of the root 12 of each blade blank 10 to produce the associated reference element.

[0086] The production of a reference element on the root 12 of each blade blank 10 here comprises the machining of each of the faces 13 of the root 12 of each blade blank 10 to produce reference surfaces on the root 12 of each blade blank 10. The machining carried out during the ninth sub-step 290 is here carried out by milling according to characteristics identical to those described with reference to the fourth sub-step 240.

[0087] In [Fig. 7], the first axis A1 of the tubular part 20 and one of the pairs 33 of jaws 32 of the first plate 30 are shown in sub-figure 7a and sub-figure 7f. These elements must be considered as present in the same way in sub-figures 7b to 7e and 7g to 7i although they have not been shown. Sub-figure 7j shows the tubular part 20 as obtained during the implementation of the sub-process 200 according to the first embodiment, i.e. as obtained after implementation of the second step 120 of the manufacturing method 100 of the present description.

[0088] The second step 120 of the manufacturing method 100 thus makes it possible to obtain the plurality of blade blanks 10 from a tubular part 20 having the minimum excess material relative to the quantity of material required to form the plurality of blade blanks 10. In other words, the tubular part 20 can thus be optimized to have a shape as close as possible to the plurality of blade blanks 10 to be manufactured. Milling is thus improved and the quantity of wasted material is reduced. The number of machining operations to obtain the plurality of blade blanks 10 is also reduced. As a result, the costs associated with obtaining the plurality of blade blanks 10 are reduced.

[0089] The manufacturing method 100 comprises a third step 130, shown in sub-figure 5c and in [Fig.9], which comprises separating the blade blanks 10 from each other. The separation of the blade blanks 10 comprises sectorizing the tubular part 20 around the first axis A1 by cuts along a cutting plane which passes circumferentially between two roots 12 of two circumferentially consecutive blade blanks 10 around the first axis A1 and the two heels 14 of the consecutive blade blanks 10 considered. Here, the blade blanks 10 are separated individually.

[0090] The separation of the blade blanks 10 is here carried out by water jet cutting. The water jet cutting operations can be carried out with a tool, in particular a cutting nozzle 36, movable along 2 to 6 axes. Here, the nozzle 36 is at least movable along an axis parallel to the first axis A1 of the tubular part 20. The pressure of the water jet can be between 2000 bars and 8000 bars. The cutting speed for the water jet cutting operations can be between 1 mm.min-1 and 1000 mm.min-1.

[0091] Remarkably, in [Fig.9], the tubular part 20 is clamped in the direction of the first axis A1 between two second plates 34 extending perpendicularly to the first axis A1 during the separation of the blade blanks 10 from each other. Each blade blank 10 is thus held after having been separated from the other blade blanks 10. In particular, each end face of the tubular part 20 in the direction of the first axis A1 bears on one of the second plates 34 in the direction of the first axis A1.

[0092] The third step 130 can furthermore be carried out on the same machine tool as that used for the second step 120. In particular, one of the two second plates 34 can coincide with the first plate 30. This minimizes the number of disassembly and positioning operations of the tubular part 20. This reduces the manufacturing time and manufacturing costs.

[0093] Reference is now made to Figures 11 to 13. [Fig. 11] is a functional diagram of a second embodiment of a sub-process 200' implemented during the second step 120 of the manufacturing method 100. [Fig. 13] represents sche automatically the sub-process 200' according to the second embodiment.

[0094] As shown in transparency in [Fig. 12], the second embodiment of the sub-process 200' implemented during the second step 120 of the manufacturing method 100 differs from the first embodiment in that the tubular part 20 comprises a non-functional part 29 at the second end 24. The term "non-functional" used in reference to the non-functional part 29 of the tubular part 20 makes it possible to indicate that the part thus qualified is not intended to be machined for the production of all or part of a blade blank 10.

[0095] The sub-process 200' according to the second embodiment comprises a first sub-step 210' shown in sub-figure 13a. The first sub-step 210' comprises holding the tubular part 20 at the second end 24 of the tubular part 20, i.e. at the non-functional part 29 of the tubular part 20. Remarkably, the remaining part of the tubular part 20 from which the blade blank 10 will be obtained remains free.

[0096] The sub-process 200' according to the second embodiment comprises a second sub-step 220' shown in sub-figure 13b. The second sub-step 220' firstly comprises the machining of the first end 22 of the tubular part 20 so as to produce a plurality of circumferentially distinct roots 12, each corresponding to a blade blank 10. The second sub-step 220' further comprises the machining of the tubular part 20 between the first end 22 and the second end 24 so as to produce an internal annular surface 26 and an external annular surface 28, the core 16 and the root 12 of each blade blank 10 being arranged between the internal annular surface 26 and the external annular surface 28.

[0097] The sub-process 200' according to the second embodiment comprises a third sub-step 230' shown in sub-figure 13c. The third sub-step 230' is carried out when the tubular part 20 is held at the non-functional part 29 and after having machined each blade blank 10. The third sub-step 230' comprises the machining of the heel 14 and the root 12 of each blade blank 10 to produce the associated reference element.

[0098] The production of a reference element on the root 12 and the heel 14 of each blade blank 10 here comprises the machining of each of the faces 13, 15 respectively of the root 12 and the heel 14 of each blade blank 10 to produce reference surfaces on the root 12 and the heel 14 of each blade blank 10.

[0099] The sub-process 200' according to the second embodiment comprises a fourth sub-step 240' shown in sub-figure 13d. The fourth sub-step 240' comprises cutting the functional part 29 from the rest of the tubular part 20 before separating the blade blanks 10 from each other.

[0100] The second embodiment of the sub-process 200' implemented during the second step 120 of the manufacturing method 100 makes it possible to completely machine each blade blank 10 while avoiding changing the holding area of ​​the tubular part 20. The number of operations to obtain the plurality of blade blanks 10 is further reduced. As a result, the costs associated with obtaining the plurality of blade blanks 10 are reduced.

[0101] The invention is not limited to the examples described above and is susceptible to numerous variants.

[0102] According to a variant which is also shown in [Fig.8], the production of a reference element on the root 12 and the heel 14 of each blade blank 10 may comprise a groove respectively on the root 12 and the heel 14 of each blade blank 10.

[0103] The grooving on the root 12 and the heel 14 of each blade blank 10 may comprise the production of a groove 17 on the root 12, respectively the heel 14. In the example shown in the figure, each groove 17 extends on only one side of the heel 14 of the corresponding blade blank 10. Each groove may be machined so as to extend annularly around the longitudinal axis X of the corresponding blade blank 10.

Claims

Claims

1. A method of manufacturing (100) turbomachine blades, the manufacturing method (100) comprising the steps of: - providing a tubular part (20) extending along a first axis (Al) between a first (22) end and a second end (24), - machining the tubular part (20) to produce a plurality of blade blanks (10), each blade blank (10) comprising a core (16) extending along a longitudinal axis (X) between a first end portion (12; 14) and a second end portion (12; 14), - machining the first end portion (12; 14) and / or the second end portion (12; 14) of each blade blank (10) to produce a reference element, - separating the blade blanks (10) from each other.

2. A manufacturing method (100) according to claim 1, wherein producing a reference element on the first end portion (12; 14) and / or the second end portion (12; 14) of each blade blank (10) comprises machining at least one face (13; 15) of the end portion (12; 14) considered of each blade blank (10) to produce a reference surface.

3. A manufacturing method (100) according to any one of the preceding claims, wherein the production of a reference element on the first end portion (12; 14) and / or the second end portion (12; 14) of each blade blank (10) comprises grooving on the end portion (12; 14) considered of each blade blank (10).

4. Manufacturing method (100) according to any one of the preceding claims, wherein the longitudinal axis (X) of each blade blank (10) extends parallel to the first axis (Al) of the tubular part (20).

5. A manufacturing method (100) according to any preceding claim, wherein the tubular part (20) is clamped in the direction of the first axis (Al) between two plates (34) extending perpendicular to the first axis (Al) when separating the blade blanks (10) from each other.

6. Manufacturing method (100) according to any one of the preceding claims, wherein the production of each blade blank (10) comprises the sub-steps: - holding the tubular part (20) at the first end (12; 14), the second end (12; 14) having remained free, - machining the second end (12; 14) of the tubular part (20) so as to produce a plurality of circumferentially distinct second end portions (12; 14), each corresponding to a blade blank (10), - machining the tubular part (20) between the first end (12; 14) and the second end (12; 14) so ​​as to produce an internal annular surface (26) and an external annular surface (28), the core (16) of each blade blank (10) being arranged between the internal annular surface (26) and the external annular surface (28).

7. Manufacturing method (100) according to the preceding claim, wherein the production of each blade blank (10) further comprises the sub-steps: - holding the tubular part (20) at the second end (12; 14), the first end (12; 14) having remained free - machining the first end (12; 14) of the tubular part (20) so as to produce a plurality of circumferentially distinct first end portions (12; 14), each being associated with a blade blank (10).

8. Manufacturing method (100) according to the preceding claim, wherein the tubular part (20) is turned over before being held at the second end (12; 14) and wherein an angular indexing appendage (25) around the first axis is produced on the tubular part (20) before the tubular part (20) is turned over.

9. A manufacturing method (100) according to any one of claims 6 to 8, wherein the tubular part (20) comprises a non-functional portion (29) at the first end (12; 14), the tubular part (20) being held at the non-functional portion (29), the first end portion (12; 14) of each blade blank (20) being arranged between the inner annular surface (26) and the outer annular surface (28).

10. A manufacturing method (100) according to any one of claims 6 to 9, wherein when the tubular part (20) is held at the first end (12; 14) and after having machined the second end portion (12; 14) of each blade blank (10), the second end portion (12; 14) of each blade blank (10) is machined to produce the associated reference element, and / or wherein when the tubular part (20) is held in position at the level of the second end (12; 14) and after having machined the first end portion (12; 14) of each blade blank (10), the first end portion (12; 14) of each blade blank (10) is machined to produce the associated reference element.

Images