TECHNICAL AREA
The present invention relates to a method for producing by additive fabrication of a blade of an aircraft turbine engine, which may be part of a nozzle sector or aircraft turbomachine stator.
STATE OF THE ART
L'état de l'art comprend notamment les documents FR-A1 - 2 991 613, FR-A1 -3 030 323, WO-A1 -2012/001324 US-A1 -2004/031780 and FR-A1 -3 002 1 67.
A turbomachine nozzle sector comprises two circumferential walls, respectively upper and lower, between which extend the blades each having a leading edge and a trailing edge extending between the walls. The blades leading edges are located on the first circumferential edges of the side walls and may be at least partly screw-à-vis removing the circumferential edges. Similarly, the blades of the trailing edges are located on the side of second circumferential edges of the walls and may be at least partly screw-à-vis removing the circumferential edges.

In the case where such a nozzle sector would be realized by additive manufacture by powder beds laser fusion, the distributor would be realized on a support plate so that either the first circumferential edges or the second circumferential edges are manufactured first directly the support plate. In such a case, due to the aforesaid withdrawal, a play exists between all or part of the leading edge or trailing of each blade and the support plate. To avoid such a game, which may result in a collapse of the in-process material, it would be possible to use temporary support bodies of the blades. These bodies would be carried out simultaneously with the first or

second edges, at the level of the blades, and extend between the support plate and the leading edges or trailing the blades.

However, these support bodies should be removed after manufacture. This raises the question of their removal, by the simplest possible technique, without risk of damaging the blades and distributor sector. A solution consisting in using a clip to hold each support member, the detaching of the corresponding blade by performing movements back and forth, then remove it by means of the clamp, could be envisaged. However, the operator's gesture would not be precise due to the géométie of the organ and its low rigidity, it could become deformed under the force applied by the clamp, making it diffcult removal.

The invention provides a simple, efficient and economical to at least some of these problems.

DISCLOSURE OF INVENTION

The invention provides a method for producing by additive manufacture of at least one vane (that is to say of any element airfoil) of aircraft turbine engine, the blade comprising two circumferential walls, respectively upper and lower between which extend at least one blade each having a leading edge and a trailing edge extending between said walls and at least partly screw-à-vis removing first and second edges respectively of said circumferential walls, the method comprising:

- an additive manufacturing step by melting laser on beds of powder of said vane, manufacture being carried on a support plate so that said first or second circumferential edges are manufactured first directly on said support plate, at least one supporting member provisional being performed simultaneously to said first or second edges at said or each blade, and extending between said support plate and said leading edges or trailing of the blade, and

- a step of removing said at least one support member supporting bodies by breaking its connection with the leading edge or trailing associated, characterized in that the removal is carried out by means of a tool which at least one end engaged in at least one recess of the or each support member and which is pivotally moved in a plane substantially perpendicular to the leading edge or trailing associated.

The invention can be applied to a single blade, that is to say, isolated, or else a series of vanes forming a monobloc assembly called sector. The area can be a rectifier sector (for a compressor), or dispenser (for a turbine).

The invention solves the above problem. It makes it possible to stiffen the support member but also to make its removal easier operation, faster and also less burdensome for the operator. One of the problems was the lack of rigidity, the walls of the organ at risk of collapsing under the action of the clip. The presence and conformation of the recess can simplify the shape of the organ, which is thus stiffened.

The method according to the invention may comprise one or more features or steps below, each taken separately other or in combination with each other:

- said tool is a screwdriver, preferably at end or head plate,

- each member comprises a three or more recesses. The number of recesses depends for example on the contact surface between the support and the blade member,

- each member may comprise a main recess and two side recesses disposed on two opposite sides of the main recess,

- said main recess is delimited by thicker than those defining the second recesses walls; This allows the body to have sufficient strength when a withdrawal force is exerted, - the method is applied to a series of blades belonging to the same nozzle sector or rectifier.

The present invention also relates to a turbomachine blade aircraft produced by the method as described above, said blade having two circumferential walls, respectively upper and lower, between which extend at least one blade each having a board leading and a trailing edge extending between said walls and at least partly in facing relation withdrawal respectively of first and second circumferential edges of said walls, at least a temporary support member being located at the leading edge or leakage of said or each blade, and extending between a plane passing through said first or second edges and said leading edge or trailing of said or each blade,characterized in that said or each support member comprises at least one recess configured to receive at least an end of a tool, for the removal by pivoting of said member.

The blade of the invention may comprise one or more features or steps below, each taken separately other or in combination with each other:

- each member comprises a three recesses or more,

- the or each recess is bounded by transverse walls reinforcing,

- each member has a thickness which varies between one end located on the side of the bottom wall, and an opposite side end of the top wall,

- each member comprises at least one lightening cavity; this type of cavity can further reduce the melting time and the consumption of powder at the additive manufacturing,

- each relief cavity is delimited by side walls of the organ which comprise lightening recesses,

- said relief grooves each have a generally V-shaped; this configuration may allow to facilitate the evacuation of the powder of the cavities at a dépoudrage operation at the end of the additive manufacturing operation; it can also reduce the melting time and the powder consumption.

DESCRIPTION OF FIGURES

The invention will be better understood and other details, features and advantages of the invention will become apparent from reading the following description given by way of example and with reference to the accompanying drawings in which:

- Figure 1 is a highly diagrammatic view of an installation for manufacturing the additive of a compressor stator sector,

- Figure 2 is a schematic perspective view of a stator sector realized by additive fabrication, the rectifier being in accordance with the invention,

- Figure 3 is an enlarged view of part of the rectifier area of ​​Figure 2,

- Figures 4a-4d are schematic perspective views of a stator sector and illustrate a manual step of removing the support bodies of the rectifier, and

- Figure 5 is a view corresponding to Figure 3 and showing an alternative embodiment of the invention.

DETAILED DESCRIPTION

Figure 1 shows an installation for making a additive manufacturing by rectifier sector, and particularly by selective melting of powder beds via a high energy beam such as a laser beam.

The machine comprises a tray feed 170 containing powder of a material such as a metal alloy, a roller 130 for transferring the powder from the tray 170 and apply a first Layer 1 10 of the powder on a tray support structure 180.

The machine also comprises a recycling bin 140 to recover the used powder (in particular unmelted or unsintered), and the excess powder (mostly), after spreading the layer of powder on the support plate 180. Thus, the most of the powder of the recycling bin is made up of new powder. Also, this recycle bin 140 is commonly referred to by the industry tray overflow or ashtray.

This machine also includes a generator 190 of energy beam (e.g. laser) 195, and a control system 150 adapted to direct the beam 195 on any region of the support plate 180 so as to scan any region of a layer of powder. Shaping the energy beam (laser) and the variation of its diameter on the focal plane are respectively by means of a beam expander 152 and a focusing system 154, all constituting the optical system.

This machine for applying the method assimilable to a direct deposition method of metal or DMD (acronym for Direct Metal Deposition) on a powder may be used any high-energy beam instead of the laser beam 195, as this beam energy is sufficient to melt in the first case or in the other form of collars or bridges between the powder particles and part of the material on which the particles are based.

The roller 130 may be replaced by other suitable application system, such as a reel (or hopper) associated with a scraper blade, a knife or a brush capable of transferring and spreading the powder layer.

The control system 150 comprises for example at least one rotatable mirror 155 on which the laser beam 195 is reflected before reaching a powder layer in which each point of the surface is always located at the same height relative to the lens focusing, contained in the focusing system 154, the angular position of the mirror 155 is driven by a galvanometric head so that the laser beam scans at least a region of the first powder layer, and thus follows a piece pre-established profile .

This machine works as follows. Is deposited with the roller 130 a first Layer 1 10 of a powder material on the support plate 180, this powder being decanted from a supply tray 170 during a forward movement of the roller 130 and then is scraped and optionally slightly compacted at one (or more) movement (s) of the return roller 130. the excess powder is recovered from the recycling bin 140. a region is brought from this first diaper 1 10 powder, by scanning with the laser beam 195, at a temperature above the melting temperature of this powder (liquidus temperature). The galvo head is controlled by the information in the database of IT tool used to design and computer-aided manufacturing of the part to be manufactured. Thus, the particles of ground 1 60 of the first region of the diaper 1 10 are melted and form a first cable 1 15 in one piece, integral with the support plate 180. At this stage, we can also scan the beam laser multiple independent regions of said first layer to form, after melting and solidification of the material, a plurality of first cords 15 January disjoint from each other. Lowering the support plate 180 by a height corresponding to the thickness already defined in the first layer (between 20 and 100 μηπ and generally 30 to 50 μηπ). The thickness of the powder layer to fuse or consolidate remains a variable value from one layer to the other because it is highly dependent on the porosity of the powder bed and its flatness while moving preprogrammed the support plate 180 is an invariable value within the clearance. then depositing a second layer 120 of powder on the first Layer 1 10 on the first cable 1 15 is then heated by exposure to the laser beam 195 a second region layer 120 which is located partially or fully above this first cable 1 15 so that the powder particles of the second layer region 120 are melted, with at least a portion of the first cord 1 15 and form a second bead integrally consolidated or 125, the all these two cords 1 15 and 125 forming a block integrally. For this purpose, the second cord 125 is advantageously already fully bound upon that a portion of the second cord 125 binds to the first member 1 15. It is understood that depending on the profile of the piece to be constructed, and in particular in the case of surface against undercut, it is possible that said region of the first layer January 10 is not, even partially, below said region of the second layer 120, so that in this case the first codon 1 15 and the second cord 125 does not then form a one piece block. Then continues on the part building process layer by layer by adding additional powder layer on the whole already formed. The scanning with the beam 195 used to build each layer by giving it a form consistent with the geometry of the part to be produced, for example the aforementioned lattice structures.

To reduce the contamination of the room, for example, dissolved oxygen, oxide (s) or another pollutant during fabrication layer by layer as described above, this manufacture shall be carried in an enclosure degree of controlled humidity and adapted to torque method / material, filled with an inert gas (unreactive) vis-à-vis of the material such as nitrogen (N2), argon (Ar) or helium (He ) with or without addition of a small amount of hydrogen (H2) known for its reducing power. A mixture of at least two of these gases may also be considered. To prevent contamination, including oxygen from the surrounding environment, it is common to this chamber pressure.

Thus, the selective melting or selective laser sintering allows to build with good dimensional accuracy weakly polluted rooms of which the three-dimensional geometry can be complex.

Selective melting or selective laser sintering uses further preferably spherical morphology of powders, clean (that is to say not contaminated with residual bodies from the synthesis), very thin (the dimension of each particle is between 1 and 100 μηπ and preferably between 45 and 90 μηπ), which provides an excellent surface finish of the finished part.

Selective melting or selective laser sintering also enables a reduction in manufacturing time, cost and fixed cost, compared to a molded, injected or machined in the mass.

The invention uses additive manufacturing by laser melting of powder beds to achieve a rectifier sector 10 of turbomachine. 2 shows an embodiment of the invention. This rectifier sector 10 has two circumferential walls, respectively upper 12 and lower 14, which extend between the blades January 6 each having a leading edge 18 and a trailing edge 20 extending between the walls 12, 14 and at least partially set back vis-à-vis first and respectively second circumferential edges 22, 24 of these walls. Organs 26 of temporary support are located at the leading edges 18 or trailing 20 of the blades 1 6, and extend between a plane passing through the first or second edges 22, 24 and the leading edges 18 or trailing 20 blades.

In the embodiment of Figures 2 to 4d, the unit 26 comprises a recess 28, but it could comprise several, such as three in the embodiment of Figure 5.

Each member 26 has an elongated shape and extends longitudinally between the walls 12, 14. In the example shown, its cross-sectional thickness, on the side of the upper wall 12, is wider than its lower end, located on the side of the bottom wall 14.

Each member 26 comprises a bottom wall 26a of elongate shape and extending in a plane substantially parallel to the edges 22, 24, and connected to the peripheral walls 26b, 26c, 26d substantially perpendicular to the bottom wall 26a. The upper wall 26b is situated on the side of the upper wall 12, the bottom wall 26d is located on the side of the bottom wall 14, and side walls 26c extend away from each other, between the walls 12 and 14.

The recess 28 is located substantially in the middle of the body 26 and is delimited by the side walls 26c on the one hand, and by two transverse walls 26e reinforcing the other. Each recess 28 has an elongated shape along the axis of elongation of the member, and is shaped to receive the tip of the tool 30. Between the recess 28 and the walls 26b, 26d, the body comprises between walls 26c, cavities relief 32. the walls 26c include, at the cavities 32, the relief notches 34. these notches have here the general shape of V.

The portions 26c of walls defining the recesses 28 are thickened relative to the remainder of these walls. Moreover, these portions 26c of walls comprise transverse notches 33 configured to facilitate the dépoudrage, that is to say, the evacuation of the powder located in the recess 28 at the end of additive manufacturing operation. The walls 26e are further thickened in particular compared with the rest of aforesaid walls 26c.

In the case where the first edges 22, such that the downstream edges (with reference to the gas flow in the turbine engine) would be made first when making the additive, it is understood that the downstream face of the rectifier would be the lower face which would be in contact with the support plate 180 of Figure 1. blades trailing edges are oriented support plate 180.

In this case, support members 26 are made simultaneously to the edges 22, for additive manufacturing, and provide support for the blades 1 June to prevent their collapse. They are thus intended to extend between the plate 180 and the blades of the trailing edges in the example shown. Here they are supported by the walls 26b, 26c, 26d on the support plate 180, and connected by material continuity to the blades 1 6, with their walls 26a.

According to the invention, the removal of each support member 26 is achieved by means of the tool 30 at least one end is engaged in the recess of each of the support members 26 and is pivotally moved in a plane substantially perpendicular to the leading edge (or trailing) associated.

Figures 4a to 4d illustrate removal steps of a last rectifier element 26 of a sector 10, other members having already been removed. The tool tip 30 is inserted into the recess 28 of the unit 26 (Figure 4a), then the tool 30 is pivotally moved in said plane until a rupture of the material between the edge of leakage of the blade and the member 26 (figures 4b and 4c). The member is rotated and raised by means of the tool so as to move it away from the blade and remove it from the space extending between the walls 12, 14 of the rectifier sector.

With the invention, the risk of deformation of the member 26 is limited. In addition, the removal operation is facilitated because it is fast and repeatable due to a precise position put in the organ tool.

In the particular case of the variant of Figure 5, the unit 26 comprises three recesses 28 aligned in a same plane parallel to the axis of elongation of the member, and such member removal tool may comprise three ends or points to be inserted

respectively in the recesses of the member. This spreads efforts to remove the body on the length of the latter.

While the invention has been illustrated by reference to a rectifier sector, it applies to a distributor sector. In the example shown, the sector includes several blades. Alternatively, it could comprise only one, this single blade forming a blade with the walls 12 and 14. In other words, the invention is applicable to a blade or sector, that is to say at any piece assembly having walls 12, 14 between which extend (ent) one or more blades June 1.

CLAIMS

1. Method for producing by additive manufacturing at least a blade of an aircraft turbine engine, said blade having two circumferential walls, respectively upper (12) and lower (14) between which extend at least one blade (1 6) having each a leading edge (18) and a trailing edge (20) extending between said walls and at least partly in facing relation withdrawal respectively of first and second circumferential edges of said walls, the method comprising: - an additive manufacturing step by laser melting of powder bed of said vane, manufacture being carried on a support plate (180) so that said first or second circumferential edges are manufactured directly on said first support plate,

- a step of removing said at least one support member by breaking its connection with the leading edge or trailing associated,

characterized in that the removal is carried out by means of a tool (30) having at least one end is engaged in at least one recess (28) of said or each support member and which is pivotally moved in a plane substantially perpendicular to the leading edge or trailing partner.

2. Method according to the preceding claim, wherein it is applied to a series of blades belonging to the same sector (10) dispenser or rectifier.

3. A method according to one of the preceding claims, wherein said tool (30) is a screw, preferably at end or flat head. 4. Aube aircraft turbine engine made by the method according to one of the preceding claims, said blade comprising two walls

circumferential, respectively upper (12) and lower (14) between which extend at least one blade (1 6) each having a leading edge (18) and a trailing edge (20) extending between said walls and at least partly in facing relation withdrawal respectively of first and second circumferential edges of said walls, at least one member (26) of temporary support being located at the leading edge or trailing of said or each blade and extending between a plane passing through said first or second edges and said leading edge or trailing of said or each blade, characterized in that said or each support member comprises at least one recess (28) configured to receive at least an end of a tool (30), for the removal by pivoting of said member.

5. A blade according to the preceding claim, wherein the or each recess (28) is delimited by transverse walls reinforcement (26e). 6. A blade according to claim 4 or 5, wherein each member (26) has a thickness which varies between a located side end of the bottom wall (14) and an opposite side end of the top wall (12) .

7. A blade according to one of Claims 4 to 6, wherein each member (26) comprises at least one relief recess (32).

8. A blade according to the preceding claim, wherein each cavity of relief (32) is delimited by side walls (26c) of the body which include relief notches (34).

9. A blade according to the preceding claim, wherein said relief grooves (34) each have a general shape of a V.

10. Sector (10) dispenser or rectifier comprising a series of blades according to one of claims 4 to 9, said sector forming a monobloc assembly.