The present invention relates to a method for repairing a turbomachine propeller blade, in particular a fan of this turbomachine.

​Technical background

​The prior art comprises, in particular, documents EP-A1-3045260, DE-A1-102010006384 and FR-A1-3046557.

​An aircraft turbomachine has one or more propeller (s) that can be shrouded or unshrouded. The present invention applies in particular to the blades of a fan, ie to the blades of a ducted propeller but also to other types of propellers, such as the unshrouded propellers of the turboprop, for example.

​A turbomachine propeller is traversed by an air flow and its blades can be subjected to Damage by wear or impact, for example of the FOD type (acronym of the Flying Object Damage) caused by the impact of a bird, for example on the blades.

​The present invention relates to the repair of a propeller blade having a damaged area, and more particularly to a propeller blade comprising an organic matrix composite blade (CMO) and a metal shield adhered to a leading edge of the blade.

​In a known manner, the CMO blade may include a woven preform embedded in a polymeric matrix. The preform is obtained by weaving three-dimensional carbon fibers.

​The boucl, as described in the application FR-A1-3 046 557, comprises two side wings respectively extending on a pressure side and a suction side of the blade, and a nose connecting the two wings. In particular, these two side wings and nose are highly exposed to the flow of gas that passes through the ice and are particularly subject to risks of wear by abrasion, impact or erosion.​In particular, the nose, which is oriented towards the upstream of the turbomachine and forms the leading edge of the gas flow which passes through the ice in operation, is most exposed to the risks of damage. The present invention proposes a simple, efficient and effective solution for repairing this type.

​SUMMARY OF THE INVENTION

​The present invention proposes a method for repairing a turbine engine blade of a turbomachine, in particular a turbomachine fan blade, said blade comprising a morgan matrix composite blade and a metal pellet bonded to a leading edge of the blade, the metal shield having a damaged area, the method comprising a step of recharging the damaged area, by supplying a metal material to this damaged area and laser melting the material​, and a step of adjusting the metalic area by machining the molten material. The invention thus proposes to repair the blade of the blade in situ, that is to say without takeoff and removal of the boucl from the blade of the blade. This is particularly advantageous because this simpl ifies and accelerates the repair of this type of blade and avoids the rebus of a blade when the shield is damaged but remains repaired.

​According to the invention, before said recharging and trimming steps, the method comprises a step of resetting the leading edge of the blade and a step of making the blade integral with the blade integral.

​The addition of a step of resetting the leading edge upstream of the step of recharging the damaged area makes it possible to accurately measure the actual profile (or geometry) of the damaged leading edge. Indeed, the blades after use in a turbomachine can be deformed (blade d with a real profile) and therefore do not correspond to the imports of the new blades and just just before the production (blade d) with a theoretical profile).​Thus, the method according to the invention makes it possible to specifically repair the damaged area of the blade as a function of the actual profile of its leading edge (which has been able to change with respect to its theoretical profile). In addition, this resetting step makes it possible to accurately identify the damaged area (s) on the leading edge of the blade. This allows the recharging step to deposit the strictly necessary amount of material and millimeter near the damaged area to be repaired.

​The addition of a cooling step of the blade before the recharging step makes it possible to control the temperature of the leading edge of the blade near the glue joint or the interface between the two materials (ie the metal shield of the leading edge and the organic matrix composite blade).​In fact, it is the total of the volume of the blade that is required, so as to provide the blade with a maximum acceptable temperature (which may be 1-20° c) for the glue joint during the step of depositing and melting the material on the damaged area of the blade. Thus, in general, the recharging parameters to obtain laser melting of the material are optimized, while avoiding local overheating and degradation of the blade.

​The method may include one or more of the following features and/or steps, taken alone or in combination with one another:

​-the resetting step is revised before or simultaneously in the cooling step,

​-the resetting step is revised by means of a movable feeler,

​-the blade is cooled to a temperature of between +20 and -20° C, preferably between 0 and -20° C,

​-the metal shield comprises two side wings respectively extending on a pressure side and a suction side of the blade, and a nose connecting the two wings, the damaged area being located on the nose,

​-a temperature threshold is predetermined, this temperature threshold corresponding to a maximum allowable temperature by the glue and/or the blade, the laser melting being revised by means of a Mach whose parameters are adjusted to prevent the glue and/or the blade reaching this threshold,

​-the seu is 1 -20° C,

​-the filler material is identical to the material of the slurry,

​-the filler material is TA6V,

​the filler material is a TiC titanium carbide,

​-in the recharging step at least, the blade is held on a frame such that the area is oriented upwards,

​-the zone is cooled in the recharging step,

​-The step is regenerated by conduction, by neutral gas at room temperature, by neutral gas cools, by spraying elements of the actinides or soil, etc.

​-The step is carried out by cryogenically or by Peltier effect,

​-the laser melting is revised by means of a movable laser head,

​the steps of resetting and recharging are revised by means of an apparatus comprising, respectively, the feeler and the laser head, and in which the apparatus is able to pivot, on the one hand, to bring the feeler into contact on the leading edge of the blade during the resetting step, and on the other hand, to bring the laser head opposite the leading edge of the blade during the recharging step, and

​The laser melting is revised by LM D (acronym of the Metal Deposition Laser) or laser.

​BRIEF DESCRIPTION OF THE FIGURES

​Other features and advantages of the invention will become apparent during the reading of the detailed description of the invention for the understanding of which reference is made to the accompanying drawings in which:

[F ig .1 ] La figure 1 est une vue schématique en perspective d’une aube d’hél ice de turbomachine, et en particul ier de soufflante de turbomachine,

​FIG. 2 is a schematic cross-sectional view of a blade of a blade such as that shown in FIG. 1, [FIG. 3] FIG. 3 is a partial schematic perspective view of an installation for implementing the method according to the invention,

[Fig . 4] La figure 4 est une vue schématique partielle en perspective de l’installation de la figure 3 et dans laquelle une étape de recalage est mise en œuvre,

[Fig . 5] La figure 5 est une vue schématique partielle en perspective de l’installation de la figure 3 et dans laquelle une étape de rechargement est m ise en œuvre.

​DETAILED Description OF THE INVENTION

La figure 1 montre une aube 1 0 d’hél ice et en particul ier de soufflante d’une turbomach ine d’aéronef. Cette aube 10 comprend une pale 12 en composite à matrice organique et un boucl ier métall ique 14 collé sur un bord d’attaque.

La pale 1 2 comporte en outre un bord de fuite 16, opposé au bord d’attaque, et un intrados et un extrados s’étendant entre les bords d’attaque et de fuite de la pale.

L’aube présente un axe d’allongement noté A. Une extrémité long itudinale de la pale 1 2 est libre et l’extrémité long itud inale opposée est reliée à un pied 1 8 pour la fixation de l’aube à un rotor de la turbomachine.

Comme cela est visible à la figure 2, le boucl ier 14 comporte deux ailes latérales 14a s’étendant respectivement sur l’intrados et l’extrados de la pale 12, et un nez 14b reliant les deux ailes 14a. Les ailes 14a, 14b définissent entre elles une cavité de réception du bord d’attaque de la pale 1 2, ainsi que de colle de sol idarisation du bouclier à la pale.

L’ensemble du bouclier métall ique 14 est susceptible d’être endommagé et de présenter dès lors une zone endommagée 20. Le boucl ier 14 doit alors être soumis à un procédé de réparation . En particul ier, le nez 14c est susceptible d’être endommagé comme illustré sur la figure 2. Toutefois ceci n’est qu’un exemple et la présente invention peut s’appl iquer sans d ifférenciation sur toute partie du bouclier métall ique 14.

​Advantageously, the damaged area 20, which comprises impacts or wear, is located from the top (or head) of the blade 10 to at least two thirds of the total length of the blade. The length of the blade 10 is measured with respect to its axis A of elongation. More specifically, the area 20 extends from the top of the blade 10 to the part of the shield 14 of the blade 1 0.​This med part may correspond to the curved portion of the airfoil of the leading edge of the blade 10. The nose 14c is likely to be damaged and can then be welded to a repair process.

​The invention proposes a method for repairing a damaged area 20 of a slurry 14 of a blade 10 of an ice, said method comprising:

​(a) a step of resetting the leading edge of the blade 1 2,

​(b) a step of cutting the entirety of the blade 12,

​(c) a step of recharging the zone 20, by supplying a metal material to this zone 20 and laser melting the material

​(base and most preferred), and

​(d) a step of adjusting the area 20 by machining the molten material.

​The cooling step (b) may occur after or during the resetting step (a).

​FIG. 3 shows an example of installation 22 for implementing the method according to the invention.

​This installation 22 comprises a frame 24 for fixing and positioning the blade 10. The blade 1 0 can be fixed in a fixed manner in the installation 22 by supports 23 for holding the blade 1 0. In the example, several supports 23 hold the foot 18, the trailing edge 16 and the top of the blade 10. The blade 1 0 is positioned so that its axis A is substantially horizontal.​The frame 24 May be configured so that the blade 10 is mounted so as to be movable about the axis A and may be positioned so that the shield 14, and in particular the damaged area 20, is oriented upwards as in the example shown (preferably perpendicular to the laser head 26).

​With reference to FIG. 4, the installation 22 comprises a feeler 27 able to exam by touching the leading edge of the blade 10, in particular for local to the area 20. The feeler 27 can come into contact with the edge or the top of the nose 14c of the boucl 14 and/or the pressure-side and suction surfaces of the wings 14a, 14b of the shield 14. The non-LIM shield, several points 27'to palper are illustrated in FIG. 3

​The installation 22 comprises a cooling system 30, preferably by conduction. In the example and in a non-Lim manner, the blade 10 is at least partially surrounded by the system 30. More specifically, the system 30 is installed to specifically cool the leading edge of the blade.

​With reference to FIG. 5, the plant 22 also includes a laser head 26 capable of generating a laser beam intended to be focused on the area 20. The head 26 is preferably provided with a system 28 for supplying recharging material to the area 20. The laser head 26 and the feeler 27 are movable. Advantageously, the laser head 26 and the feeler 27 are arranged on the same arm 25 of the installation 22 (visible in FIG. 4).​The arm 25 is a mobile device capable of pivoting, preferably between 90 and 180°, in order to reveal either the laser head 26 or the feeler 27 with respect to the blade 10.

​The filler material is preferably the same as the material of the slurry 14 and is, for example, TA6V. Advantageously, the filler material is a TiC titanium carbide.

Le matériau est fondu par laser et plus particulièrement par une méthode LMD ou m icro laser. Le LMD met en œuvre un faisceau laser continu alors que le m icro laser met en œuvre un faisceau par impulsions. Pour le laser continu, un laser vient chauffer le matériau de base et celu i d’apport en permanence. Par conséquent, la chaleur s’accumule dans une même zone et se propage dans la matière de base.Pour le laser pulsé, le laser“tire” en pointillé et est moins invasif, ce qu i permet de maîtriser la zone de diffusion de la chaleur.

Pour garantir la santé de l’aube 1 0, il peut être important de maîtriser avec précision la température du boucl ier 14, car plus le boucl ier est chaud et plus la chaleur peut se propager par conduction dans la colle et le matériau de la pale, et les détériorer. Un risque de fusion de la colle et de désol idarisation du boucl ier de la pale, est par exemple possible.

En pratique, un seuil de température est de préférence prédéterm iné, ce seu il de température correspondant à une température maximale admissible par la colle et/ou la pale. Les paramètres de la tête laser 26 et du système de refroid issement 30 sont de préférence réglés pour éviter que la colle et/ou la pale atteigne ce seu il . Ce seuil est par exemple de 1 20°C.

Le système de refroid issement 30 peut être conçu pour refroid ir la pale 12 ou l’aube 1 0 par cryogén ie (par exemple par projection de C02 l iquide ou de carboglace ou d’un gaz neutre refroidit en amont du circuit de projection) ou par effet Peltier. La température de

refroidissement est par exemple comprise entre +20 et -20°C, de préférence entre 0 et 20°C.

​The invention has several advantages:

​• repair of the blades more quickly in order to deliver them as soon as possible;

​• repairing by adapting to the actual airfoil profile of the service return vanes;

• ne pas avoir à retirer le boucl ier et à le nettoyer afin de retirer les résidus de colle ;

• éviter le retrait du boucl ier pour éviter les problématiques d’appairage ;

• réparer une pièce comportant un bi-matériau (matériau composite - matériau métall ique) sans util iser de moyens spécifiques du type étuve, salle blanche, mach ine à vide, etc.

• recharger le boucl ier métall ique sans altération du matériau composite (ou de la colle permettant l’assemblage bi- matériau) grâce notamment au peu d’énergie mise en œuvre en soudage laser et au système de refroidissement ;

• l im iter la déformation du bouclier indu it par le rechargement ;

• rallonger la durée de vie des aubes (susceptibles d’être déformées) pour une nouvelle m ise en service dans un turbomach ine ;

• l im iter la mise au rebut des aubes de retour de service.

WE CLAIMS

1. A method of repairing a turbine engine propeller blade (10), in particular a turbomachine fan, this blade comprising a blade (12) made of organic matrix composite and a metal shield (14) bonded to one edge blade attack, the metallic shield (14) having a damaged area (20), the method comprises a step of recharging the damaged area (20), by adding a metallic material to this damaged area (20) and laser melting of the material, and a step of adjusting the damaged area (20) by machining the molten material, characterized in that before the said resurfacing and adjusting steps, the method comprises a step of resetting of the leading edge of the blade (12) and a step of cooling the entire said blade (12).

2. Method according to sells ication 1, in which the resetting step is carried out before or simultaneously with the cooling step.

3. Method according to sells ication 1 or 2, in which the resetting step is carried out by means of a mobile feeler (27).

4. Method according to one of the preceding claims, wherein the blade (1 2) is cooled, ie to a temperature between

+20 and -20 ° C, preferably between 0 and -20 ° C.

5. Method according to one of the preceding claims, wherein the cooling is provided by cryogenization or by the Peltier effect.

6. Method according to one of the preceding claims, wherein the metal shield (14) comprises two side wings (14a, 14b) extending respectively over an intrados and an extrados of the blade, and a nose (14c) connecting the two wings, the damaged area (20) being located on the nose (14c).

7. Method according to any one of claims 1 to 6, in which a temperature threshold is predetermined, this temperature threshold corresponding to a maximum temperature admissible by the adhesive and / or the blade, the laser melting being carried out. by means of a machine whose parameters are set to prevent the glue and / or the blade from reaching this threshold.

8. The method of sells ication 7, wherein the threshold is 120 ° C.

9. Method according to one of the preceding claims, wherein the filler material is identical to the material of the shield.

10. The method of sells ication 9, wherein the filler material is TA6V.

1 1. Method according to one of sells ication 1 to 8, in which the filler material is titanium carbide (TiC).

12. Method according to one of the preceding claims, wherein, during the reloading step at least, the blade (10) is maintained on a frame (24) so ​​that the area (20) is oriented. to the top.

13. Method according to one of claims 1 to 1 2, wherein the laser fusion is carried out by means of a laser head (26) movable.

14. The method of sells ication 1 3, in which the steps of resetting and reloading are carried out by means of an apparatus (25) unic comprising, respectively, the feeler (27) and the laser head (26), and in which the apparatus (25) is adapted by pivoting, on the one hand, to bring the probe (27) into contact with the leading edge of the blade (1 2) during the resetting step, and on the other hand, in placing the laser head (26) facing the leading edge of the blade (12) during the reloading step.

15. Method according to one of the preceding claims, wherein the laser fusion is real ized by LM D or mΐqebt.