Tools for local repair or remanufacturing of a composite material part

Abstract

Tool for local repair or remanufacturing of a composite material part The invention relates to a local repair tool (300) for a composite material part (400), the tool (300) comprising a flexible fixing base (310) configured to be held on a part of the composite material part comprising a damaged area (401) to be repaired, the fixing base comprising a central part (312) intended to cover the area to be repaired (401), at least one injection channel (320) opening onto an internal surface (313) of the central part (312) of the flexible fixing base (310), a heating element (360) configured to heat at least the area over which said central part (312) of the flexible fixing base (310) extends. Figure for abstract: Fig.4

Description

Title of the invention: Tool for local repair or remanufacturing of a part made of composite material Technical field

[0001] The present invention relates to the field of repair with or without disassembly and the resumption of manufacture of parts made of composite material and more particularly those of propeller blades or vanes made of composite material to be produced under the wing or in a repair factory. Prior art

[0002] The usual methods for repairing composite material parts consist of depositing a resin in the damaged area, removing the excess resin and polymerizing the assembly in a vacuum oven. These methods are carried out manually and on a non-industrial scale.

[0003] The resin is generally deposited by flow, which makes it difficult to control the amount of resin applied to the damaged area. Other techniques propose applying the resin to the damaged area using a brush. While this solution improves control of the amount of resin applied, it significantly lengthens the repair time. In addition, air bubbles can become trapped in the resin when it is applied, creating porosities in the damaged area.

[0004] Regardless of the solution used, it is also necessary to remove excess resin. Therefore, sanding or polishing the repaired part is generally carried out. This step can be tricky to implement because it risks damaging the underlying substrates of the part.

[0005] The polymerization of the part can be done under vacuum in an oven or an autoclave. The vacuum is generally achieved using a vacuum cover, seals and silicone. This polymerization technique has the disadvantage of requiring heating of the entire part, which can cause damage to the undamaged parts of it. This is the case, for example, when the part is coated with paint. In addition, the need to heat the entire part increases the cost of repair from an energy and economic point of view.

[0006] Other methods propose an arrangement of pre-impregnated patches on the damaged parts of the part.

[0007] The methods of the prior art have the disadvantage of not being able to be implemented under a wing, that is to say when the part such as a blade or a vane of propeller are in service on the aircraft. In fact, the part to be repaired is generally dismantled and sent to a repair plant.

[0008] Thus, there is a real need to carry out a repair or a resumption of manufacturing of parts made of composite material under the wing, in a repair factory or in a production factory, and this, without the drawbacks inherent in the aforementioned known methods. Presentation of the invention

[0009] According to a first aspect, the invention proposes a local repair tool for a composite material part, characterized in that it comprises a flexible fixing base configured to be held on a part of the composite material part comprising a damaged area to be repaired, the flexible fixing base comprising a central part intended to cover the damaged area to be repaired, at least one injection channel opening onto an internal surface of the central part of the flexible fixing base, a heating element configured to heat at least the area over which said central part of the flexible fixing base extends.

[0010] Such a tool allows a composite material part to be repaired directly under the wing or in a repair factory, simply and quickly. This is possible thanks to the configuration of the tool and its small size. Indeed, the tool can be fixed to the area to be repaired without needing to dismantle the part to carry out the repair. The flexibility of the flexible fixing base allows the tool to fit the shape of the part of the part comprising the damaged area to be repaired. For example, when the part is a blade or a propeller blade, the tool can be used for repairs on both the extrados side and the intrados side of the blade or propeller blade.

[0011] Such tooling also makes it possible to carry out a repair more economically and more quickly than with the solutions of the prior art. Indeed, the injection of the resin and the heat treatment take place locally on the damaged part. The process is less time-consuming because it makes it possible to avoid interventions on the part such as applying the resin to the damaged part with a brush, placing the entire composite material part under vacuum, or heating the entire composite material part.

[0012] According to another particular characteristic, the tooling may further comprise at least one first vacuum draw port opening onto the internal surface of the central part of the flexible fixing base.

[0013] Such a configuration makes it easier to inject the resin through the injection channel. In addition, this configuration makes it possible to optimize the filling of the damaged area with the resin.

[0014] Furthermore, such a configuration makes it possible to improve the insulation of the area in damaged, which is covered by the central part of the flexible fixing base, relative to the room environment.

[0015] According to a particular characteristic, the tooling may further comprise a support plate configured to apply a mechanical force to the central part of the flexible fixing base directed towards the part made of composite material. The support plate forms a plate, for example a disc, having a flat surface intended to be opposite the flexible fixing base.

[0016] Such a support plate facilitates the immobilization of the resin within the damaged area and this before and / or during the heat treatment of polymerization of the resin.

[0017] According to a particular characteristic of the tooling, the flexible fixing base may comprise an annular groove present on an internal surface of the flexible fixing base and extending around the central part of the flexible fixing base, the tooling may further comprise a second vacuum draw port opening into the annular groove.

[0018] Such a configuration makes it possible to optimize the fixing of the flexible fixing base of the tooling. Indeed, when fixing the flexible fixing base, the air present in the annular groove can be evacuated through the second vacuum draw port. Thus, it is possible to improve the adhesion of the tooling to the composite material part.

[0019] According to a particular characteristic, the tooling may further comprise a cover secured to the flexible fixing base covering the heating element.

[0020] Such a cover facilitates the fixing of the injection channel and the first draw port on the tool. In addition, such a cover facilitates the thermal insulation of the heating element of the tool. Indeed, the cover limits as much as possible the dissipation of heat from the heating element to the outside of the tool.

[0021] According to a particular characteristic of the tool, the cover can integrate a clamping device cooperating with the support plate.

[0022] Such a configuration facilitates the control of the application of the mechanical force on the support plate. Indeed, when handling the clamping device it is possible to control the direction of the force as well as its magnitude.

[0023] According to another particular characteristic of the tool, the cover may further comprise an inflatable bladder cooperating with the support plate.

[0024] Such a configuration facilitates the application of the force in a controlled and progressive manner. Indeed, the inflatable bladder can accommodate the air progressively so as to apply a progressive force on the support plate.

[0025] According to a particular characteristic, the tooling may further comprise a tear-off fabric present on the internal surface of the central part of the flexible fixing base.

[0026] Such a tear-off fabric facilitates the removal of the tooling after repairing the damaged area. In addition, the tear-off fabric helps minimize splashing of the resin on the tooling. Indeed, such a tear-off fabric absorbs splashes and excess resin from the repair. The tear-off fabric can be interchangeable as needed.

[0027] According to another aspect, the invention proposes a method for locally repairing or remanufacturing a part made of composite material, characterized in that it comprises the use of local repair tools according to the invention and in that it further comprises: - a step of fixing a flexible fixing base of the local repair tool on a part of the part comprising a damaged area to be repaired, a central part of the flexible fixing base covering the damaged area to be repaired, - a step of injecting a resin through at least one injection channel of the local repair tool into the damaged area to be repaired, - a heat treatment step for polymerization of the resin by a heating element of the local repair tool.

[0028] According to a particular characteristic, during the step of injecting the resin through at least one injection channel, the air present in said damaged area to be repaired can be extracted through a first vacuum draw port of the local repair tool.

[0029] According to another particular characteristic, the method may further comprise the application of a mechanical force by a support plate on the central part of the flexible fixing base during the heat treatment of polymerization of the resin.

[0030] Such a step makes it easier to immobilize the resin within the damaged area during the repair process.

[0031] According to a particular characteristic, the method may further comprise a step of extracting the air present in an annular groove present on an internal surface of the flexible fixing base.

[0032] Such a step makes it possible to increase the adhesion of the flexible fixing base to the composite material part. Brief description of the drawings

[0033] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting character.

[0034] [Fig.l] [Fig.l] schematically represents a blade with a damaged area,

[0035] [Fig.2] [Fig.2] is a partial sectional view of the blade of [Fig.l] according to the direction II-II,

[0036] [Fig.3a] [Fig.3a] schematically represents a tool fixed on the part of the blade comprising the damaged area according to one embodiment,

[0037] [Fig.3b] [Fig.3b] represents a zoom of the tooling of [Fig.3a],

[0038] [Fig.4] [Fig.4] is a partial sectional view of the tooling of [Fig.3b] along direction IV-IV. Description of the embodiments

[0039] The invention applies generally to the local repair or remanufacturing of a part made of composite material and, more particularly but not exclusively, to the repair or remanufacturing of a blade or propeller blade made of composite material. It uses specific tooling 300 which will be described here in relation to the repair of a blade made of composite material.

[0040] [Fig.l] illustrates a blade 400 which has a portion comprising a damaged area 401 resulting for example from an impact with an object ingested by the engine fan, for example a bird, debris, ice, etc.

[0041] In [Fig.2] and in the example described here, the blade 400 comprises an organic matrix composite material 100 defining the general shape of the blade and in particular its volume.

[0042] [Fig.3a] illustrates a tool 300 fixed on a part of the blade comprising the damaged zone 401. The tool 300 is intended to locally repair the blade 400 comprising the damaged zone 401.

[0043] As illustrated in [Fig. 3b], the tooling comprises a flexible attachment base 310, an injection channel 320, a first vacuum draw port 330 and a heating element 360. The flexible attachment base 310 of the tooling 300 of [Fig. 3a] has a circular shape. However, the flexible attachment base 310 may have other shapes. For example, the flexible attachment base 310 may have a rectangular shape, a square shape, an elliptical shape, etc. By "flexible attachment base" is meant that the attachment base is elastically deformable. The flexible attachment base 310 is chemically inert with respect to the resin and resists the polymerization temperature of the resin. The flexible attachment base 310 may be made of a material selected from silicone and neoprene.

[0044] The flexible attachment base 310 is configured to be held on the part of the blade 400 comprising a damaged area 401 to be repaired. Indeed, the flexible attachment base 310 is capable of matching the surface of the part of the blade 400 comprising the damaged area 401. The flexible attachment base 310 can be attached both to an intrados side of the blade 400 and to an extrados side of the blade 400. The flexible attachment base 310 comprises a peripheral part 311 and a central part 312. The central part 312 of the flexible attachment base 310 comprises an internal surface 313. The central part 312 of the flexible attachment base 310 covers the part of the blade 400 including the damaged area 401 to be repaired, as illustrated in [Fig.4].

[0045] The flexible attachment base 310 may include features facilitating attachment of the tooling 300 to the blade 400. For example, the flexible attachment base 310 may include an annular groove 341 that is present on the inner surface 313 of the central portion 312 of the flexible attachment base 310, as illustrated in [Fig. 4]. The annular groove 341 extends around the central portion 312 of the attachment base 310. The annular groove 341 is part of the peripheral portion 311 of the flexible attachment base 310 ([Fig. 4]). The tooling 300 further includes a second vacuum draw port 340 that opens into the annular groove 341. The annular groove 341 may be connected to a vacuum pump (not illustrated). When the flexible attachment base 310 is attached, the air present in the groove 341 is extracted through the second vacuum draw port 340, thus creating a suction effect which reinforces the adhesion of the flexible attachment base 310 on the blade 400.

[0046] According to another embodiment which is not that illustrated, the annular groove 341 may comprise a sealing gasket resistant to the polymerization temperature.

[0047] Such a configuration makes it possible to optimize the insulation of the part of the part comprising the damaged area to be repaired (covered by the central area of the tool) relative to the environment of the part.

[0048] Indeed, when fixing the flexible fixing base 310, the sealing gasket is compressed between the part and the tooling 300.

[0049] When the annular groove 341 includes the seal, it is not necessarily necessary to have a second vacuum draw port.

[0050] According to another embodiment, the tooling 300 may comprise an adhesive strip present on an internal surface 313 of the flexible fixing base 310 and extending around the central portion 312 of the flexible fixing base 310. The adhesive strip may be changed at the end of each use of the tooling 300.

[0051] Such a configuration makes it possible to optimize the fixing of the flexible fixing base of the tool. Indeed, when fixing the flexible fixing base 310, the adhesive strip is stuck to the wall of the blade or the composite material part. Thus, it is possible to improve the adhesion of the tool to the composite material part.

[0052] The adhesive strip can be used in addition to the annular groove 341 and the annular groove in this case being placed between the adhesive strip and the central part 312.

[0053] The injection channel 320 of the tooling 300 opens onto the inner surface 313 of the central portion 312 of the flexible fixing base 310, as illustrated in [Fig. 4]. A resin can be introduced through the injection channel 320. The number of injection channels 320 and the number of first vacuum draw ports 330 are not limiting. Thus, in one embodiment, the tooling 300 may comprise a plurality of injection channels 320 and a plurality of first vacuum draw ports 330 opening onto the inner surface 313 of the central portion 312 of the flexible fixing base 310. Such an arrangement facilitates a homogeneous distribution of the resin in the damaged area 401 to be repaired. In an embodiment which is not that illustrated, the tooling 300 may comprise a syringe or any other device for injecting a resin.

[0054] The heating element 360 is configured to heat the area over which the central portion 312 of the attachment base 310 extends, as illustrated in [Fig. 4]. Indeed, the heating element 360 heats the central portion 312 of the flexible attachment base 310. The central portion 312 transmits the heat to the portion of the blade 400 comprising the damaged area 401 to be repaired. The heating element 360 has a circular shape as illustrated in FIGS. 3b and 4. Such a shape facilitates uniform heating of the entire central portion 312 of the flexible attachment base 310. Other shapes can also be envisaged for the heating element 360.

[0055] The tool 300 may further comprise a cover 350 which is integral with the fixing base 310. The cover 350 covers the heating element 360. The cover 350 makes it possible to limit the dissipation of heat from the heating element 360 to the outside of the tool 300. In addition, the cover 350 comprises a first orifice 351 and a second orifice 352. The first orifice 351 forms a passage making it possible to connect the injection channel 320 to the flexible fixing base 310. The second orifice 352 forms a passage making it possible to connect the first vacuum draw port 330 to the flexible fixing base 310. Such a configuration makes it possible to reinforce the rigidity of the tool 300. The number of orifices is not limiting. Indeed, when the tool 300 is provided with several injection channels 320 and several first vacuum draw ports 330, the cover 350 can comprise an equivalent number of orifices.

[0056] The tooling 300 may further comprise a support plate 370, as illustrated in FIGS. 3b and 4. Such a support plate 370 is configured to apply a mechanical force to the central portion 312 of the flexible fixing base 310. In the example illustrated in [Fig. 4], the support plate 370 forms a disc and has a flat surface 371 which faces the flexible fixing base 310. The support plate 370 may have other shapes. For example, the support plate 370 may have a rectangular, square, etc. shape.

[0057] As illustrated in [Fig. 4], the cover 350 of the tool 300 may incorporate a clamping device 372, such as a clamping screw. The clamping device 372 extends lengthwise in a Y direction orthogonal to the flexible fixing base. 310. The clamping device 372 cooperates with the support plate 370. The clamping device 372 applies a mechanical force to the flat surface 371 of the support plate 370 and the latter in turn applies a mechanical force to the central portion 312 of the flexible fixing base 310. When the tooling 300 comprises such a clamping device 372, the cover 350 may comprise a third orifice 353, as illustrated in FIGS. 3b and 4. The third orifice 353 forms a passage for the clamping device 372. When a mechanical force is applied, the clamping device 372 moves in a direction Y orthogonal to the flexible fixing base 310 and this, through the third orifice 353. The clamping device 372 may comprise a sensor measuring the magnitude of the mechanical force applied to the central portion 312 of the 310 flexible mounting base.

[0058] In a variant, the clamping device may comprise, instead of the screw, a spring fitted onto a rod. The rod and the spring extend between the cover 350 and the support plate 370 in a direction Y orthogonal to the flexible fixing base 310. The spring applies a mechanical force to the flat surface 371 of the support plate 370 and the latter in turn applies a mechanical force to the central portion 312 of the flexible fixing base 310. Such a configuration makes it possible to increase the mechanical force that can be applied to the flat surface 371 of the support plate 370.

[0059] In another embodiment which is not the one illustrated, the cover 350 may comprise an inflatable bladder in place of the clamping device 372. In this case, the inflatable bladder cooperates with the plate 370 to apply the mechanical force. In this case, the inflatable bladder applies a mechanical force to the support plate and the latter in turn applies a mechanical force to the central portion of the flexible fixing base. The inflatable bladder may comprise a sensor measuring the magnitude of the mechanical force applied to the central portion 312 of the flexible fixing base 310.

[0060] The tooling may further comprise a tear-off fabric 380. The tear-off fabric 380 is present on the inner surface 313 of the central portion 312 of the flexible fixing base 310. The tear-off fabric 380 is chemically inert with respect to the resin used for the repair. The tear-off fabric 380 also has good resistance to the temperature of the polymerization heat treatment. Such a tear-off fabric 380 may be made of a material chosen from polyamides, polyesters, glass fibers or a mixture thereof.

[0061] The tear fabric 380 may be made of Polyhexamethylene adipamide more commonly known as Nylon.

[0062] An example of the method for local repair of a composite material blade is now described. The method is implemented using the tooling described above.

[0063] In a first step, the flexible fixing base 310 of the tool 300 is placed on the part of the blade 400 comprising a damaged area 401 to be repaired, as illustrated in [Fig. 3a]. The central part 312 of the flexible fixing base 310 of the tool 300 covers the damaged area 401 to be repaired. When the flexible fixing base 310 comprises an annular groove 341, the method comprises a step of extracting the air present in the annular groove 341, which makes it possible to increase the adhesion of the flexible fixing base 310 to the wall of the blade 400.

[0064] Next, a step of injecting a resin into the damaged area 401 to be repaired is carried out. During this step, the resin is injected through the injection channel 320. The injection of the resin can be carried out using a syringe or any other resin injection device. When the tooling comprises a first vacuum draw port 330, the air present in the damaged area 401 to be repaired is extracted through the first vacuum draw port 330 during the injection of the resin.

[0065] Examples of resins that may be used are polyester resins, epoxy resins and phenolic resins.

[0066] Once the resin has been injected, a heat treatment step is carried out to polymerize the resin, implemented by the heating element described above. The polymerization process is carried out at a temperature between 23 and 400°C.

[0067] The method then comprises a demolding step during which the tooling 300 is removed from the blade 400.

[0068] The method may further comprise applying a mechanical force by the support plate 370 to the central portion 312 of the flexible fixing base 310 during the polymerization heat treatment. Such application of the mechanical force may also be carried out after the injection of the resin and before the polymerization heat treatment. The mechanical force may for example be applied by means of a clamping device 372 or an inflatable bladder as described previously.

Claims

Claims

1. Tool (300) for local repair or remanufacturing of a composite material part, characterized in that it comprises a flexible fixing base (310) configured to be held on a part of the composite material part comprising a damaged area (401) to be repaired, the fixing base comprising a central part (312) intended to cover the damaged area (401) to be repaired, at least one injection channel (320) opening onto an internal surface (313) of the central part (312) of the flexible fixing base (310), a heating element (360) configured to heat at least the area over which said central part (312) of the flexible fixing base (310) extends.

2. Tooling according to claim 1, further comprising a first vacuum draw port (330) opening onto the internal surface (313) of the central portion (312) of the flexible fixing base (310).

3. Tooling according to claim 1 or 2, further comprising a support plate (370) configured to apply a mechanical force on the central part (312) of the flexible fixing base (310) directed towards the composite material part.

4. Tooling according to any one of claims 1 to 3, wherein the flexible fixing base (310) comprises an annular groove (341) present on an inner surface (313) of the flexible fixing base (310) and extending around the central portion (312) of the flexible fixing base (310), the tooling (300) further comprising a second vacuum draw port (340) opening into the annular groove (341).

5. Tooling according to any one of claims 1 to 4, further comprising a cover (350) integral with the flexible fixing base (310) covering the heating element (360).

6. Tooling according to claim 5, in which the cover (350) incorporates a clamping device (372) cooperating with the support plate (370).

7. Tooling according to claim 5, wherein the cover (350) further comprises an inflatable bladder cooperating with the support plate (370).

8. Tooling according to one of claims 1 to 7, further comprising a tear-off fabric (380) present on the internal surface (313) of the central part (312) of the flexible fixing base (310).

9. Method for locally repairing or remanufacturing a part (400) made of composite material, characterized in that it comprises the use of a local repair tool (300) according to any one of claims 1 to 8 and in that it further comprises: - a step of fixing a flexible fixing base (310) of the local repair tool (300) on a part of the part (400) comprising a damaged area (401) to be repaired, a central part (312) of the flexible fixing base (310) covering the damaged area (401) to be repaired, - a step of injecting a resin through at least one injection channel (320) of the local repair tool into the damaged area (401) to be repaired, - a step of heat treatment for polymerization of the resin by a heating element (360) of the local repair tool (300).

10. Method according to claim 9, wherein during the step of injecting a resin through said at least one injection channel (320), the air present in said damaged area to be repaired is extracted through a first vacuum draw port (330) of the local repair tool.

11. Method according to claim 9 or 10, further comprising the application of a mechanical force by a support plate (370) on the central part (312) of the flexible fixing base (310) during the heat treatment of polymerization of the resin.

12. A method according to any one of claims 9 to 11, further comprising a step of extracting air present in an annular groove (341) present on an inner surface (313) of the flexible fixing base (310).

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