FR3046563A1 - TOOTH-HOLDING AND TRANSPORT TOOLS FOR A FIBROUS PREFORM AND METHOD FOR MANUFACTURING A COMPOSITE MATERIAL PART - Google Patents

Abstract

A holding and conveying tool (300) for a fibrous structure (200) comprising a first shell (310) comprising at its center a first cavity (311), the first cavity being surrounded by a first contact plane ( 312) and a second shell (320) comprising at its center a second cavity (321), the second cavity being surrounded by a second contact plane (322) intended to cooperate with the first contact plane (312). The first and second indentations (311, 321) together define an internal volume (301) having the shape of a part to be produced when the first and second shells (310, 320) are in a determined assembly position. The tooling further comprises locking means in position for holding the first and second shells (310, 320) in the assembly position determined so as to allow the handling and transport of said tooling without relative movement between the two assembled shells .

Description

BACKGROUND OF THE INVENTION The invention relates to turbomachine parts of composite material comprising a fiber reinforcement densified by a matrix, the matrix being obtained by injection of a liquid composition containing a precursor of the matrix in a fiber preform.

A targeted field is that of gas turbine blades for aircraft engines or industrial turbines.

The manufacture of a blade of composite material comprises the following steps: a) production of a fibrous structure by three-dimensional weaving or multilayer weaving, b) placement of the fibrous structure in compaction and forming tools, c) application of a compacting pressure on the fibrous structure present in the compaction and forming tool so as to obtain a fibrous preform of the blade to be produced, d) extraction of the fibrous preform from the compacting and forming tool, e) transporting the fiber preform to an injection tool, f) placing the fiber preform in the injection tool, g) closing the injection tool, h) injecting a liquid precursor composition, and a matrix material such as a resin in the fibrous preform, i) converting the liquid composition into a matrix so as to obtain a blade made of a composite material comprising a fibrous reinforcement densified by a matrix this. The extraction of the preform from the compacting and forming tooling as well as the transport of the preform to the tooling for performing die precursor injection into the preform are delicate operations that can lead to anomalies. in the manufacture of the composite material part. Indeed, the extraction of the preform of the compacting tool and its transport to an injection tooling are performed manually by an operator. These manual actions on the preform decreases the robustness of the manufacturing process of a composite material part. They can also cause deformations in the preform which lead to anomalies in the resulting structure that may affect the mechanical properties of the manufactured part.

Object and summary of the invention

The present invention therefore aims to provide a solution for handling and transporting a fiber preform under reliable and reproducible conditions to ensure good quality of manufacture of composite parts. For this purpose, the invention proposes in particular a tool for holding in shape and transport for a fibrous structure or preform comprising a first shell comprising in its center a first impression, the first impression being surrounded by a first contact plane and a second shell comprising in its center a second cavity, the second cavity being surrounded by a second contact plane intended to cooperate with the first contact plane, the first and second indentations together defining an internal volume having the shape of a final part to be performed when the first and second shells are in a determined assembly position, the tooling further comprising locking means in position to hold the first and second shells in the assembly position determined so as to allow handling and transporting said tooling without relative displacement between the two shells s assembled.

Thus, a fiber preform can be obtained directly in the tool for holding and transporting the invention which is then used for transporting the preform during the subsequent steps of manufacturing a piece of composite material. The preform can not undergo any deformation because it is protected inside the tooling of the invention.

According to a first aspect of the tool for keeping fit and transport of the invention, the first shell comprises at least one port in communication with the internal volume of the tool while the second shell comprises at least one port in communication with the internal volume of the tooling. In another aspect, ports in communication with the internal volume of the tool may be present on the first shell or on the second shell. In all these cases, the tooling is suitable for use with an injection tooling because the ports present on the tool for keeping fit and transport of the invention can be used to, on the one hand, inject into the fiber preform a precursor matrix liquid composition and, secondly, create a pressure gradient in the tool to force the liquid composition to impregnate the entire volume of the preform.

According to one embodiment of the tool for holding in shape and transport of the invention, it comprises a plurality of clamping devices distributed around the first and second shells.

According to another embodiment of the tool for holding and transporting the invention, it comprises a plurality of lever closure devices distributed around the first and second shells. The tooling preferably comprises four clamping or lever closure devices, a device being present on each lateral face of the tooling.

According to a particular characteristic of the tool for holding in shape and transport of the invention, at least one of the two shells is provided with a carrying handle. This facilitates the handling and transport of the tooling, particularly when a fibrous preform is present inside. The subject of the invention is also a process for manufacturing a composite material part comprising the following steps: a) production of a fibrous structure by three-dimensional weaving or multilayer weaving, b) placement of the fibrous structure in a compacting tool and of forming, c) application of compaction pressure on the fibrous structure present in the compaction and forming tool so as to obtain a fibrous preform of the workpiece, d) transport of the fibrous preform to a injection tooling, e) placing the fiber preform in the injection tool, f) closing the injection tool, g) injecting a liquid composition comprising at least one precursor of a matrix material in the fiber preform, h) converting the liquid composition into a matrix so as to obtain a composite material part comprising a matrix-densified fiber reinforcement, characterized in that that, before step b), the fibrous structure is placed in a tool for keeping fit and transport according to the invention and in that the fibrous preform obtained after step c) is maintained in said holding tool in form and transport when performing steps d) to h).

The composite material part may in particular correspond to an aeronautical engine fan blade.

BRIEF DESCRIPTION OF THE DRAWINGS Other features and advantages of the invention will emerge from the following description of particular embodiments of the invention, given by way of non-limiting example, with reference to the appended drawings, in which: FIG. 1 very schematically illustrates a three-dimensional woven fiber blank for producing a fibrous structure according to an embodiment of the invention; Figure 2 is a schematic view of a fibrous structure obtained from the fibrous blank of Figure 1; Fig. 3 is an exploded schematic perspective view showing a shaped holding and conveying tool according to an embodiment of the invention and placing the fibrous structure of Fig. 2 therein; Figure 4 is a schematic perspective view of the tool of Figure 3 once mounted; Figure 5 is a schematic perspective view showing the placement of the shaped holding and transport tooling of Figure 4 in a compaction tool and forming; Figure 6 shows a compaction and forming operation with the tools of Figure 5; Figure 7 is a schematic perspective view showing the placement of the shaped holding and transport tool of Figure 6 in an injection tool; Figure 8 shows an operation of injecting a liquid matrix precursor composition into a fiber preform with the tools of Figure 7; Figure 9 is a partial schematic perspective view showing the locking means in position of the shells of the shaped holding tool and transport according to one embodiment; FIG. 10 is a partial schematic perspective view showing locking means in position of the shells of the shaped holding and transport tool according to another embodiment; FIG. 11 is a partial schematic perspective view showing means for locking the shells of the shaped and transport holding tool in accordance with yet another embodiment; Fig. 12 is a partial schematic perspective view showing a shaped holding and carrying tool equipped with carrying handles according to one embodiment; Figure 13 is a schematic perspective view of a turbomachine blade made of composite material obtained according to a manufacturing method of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS The invention is generally applicable to the production of composite material parts, the parts being made from a fiber preform in which a precursor liquid composition of a matrix material is injected then transformed so as to obtain a part comprising a fiber reinforcement densified by a matrix.

In the remainder of the description, the present invention is described in application of the manufacture of a blade made of a gas turbine composite material, such as an aeronautical engine blade.

The method of manufacturing a blade of composite material according to the invention begins with the production of a fibrous blank obtained by three-dimensional weaving or by multilayer weaving.

By "three-dimensional weaving" or "3D weaving" is meant here a weaving mode whereby at least some of the warp son bind weft son on several weft layers such as "interlock weaving". By "interlock weaving" is meant here a 3D weave armor each chain layer links several layers of frames with all the son of the same chain column having the same movement in the plane of the armor.

By "multilayer weaving" is meant here a 3D weave with several weft layers whose basic armor of each layer is equivalent to a conventional 2D fabric weave, such as a linen, satin or twill type armor, but with some points of the weave that bind the weft layers between them.

The production of the fibrous structure by 3D or multilayer weaving makes it possible to obtain a bond between the layers, and thus to have good mechanical strength of the fibrous structure and of the composite material part obtained, in a single textile operation.

It may be advantageous to promote obtaining, after densification, a surface condition free of major irregularities, that is to say, a good state of completion to avoid or limit finishing operations by machining or to avoid the formation of resin clumps in the case of resin matrix composites. For this purpose, in the case of a fibrous structure having an inner part, or core, and an outer part, or skin adjacent to an outer surface of the fibrous structure, the skin is preferably made by weaving with a type of armor canvas, satin or twill to limit surface irregularities, a satin-like weave providing a smooth surface appearance.

It is also possible to vary the three-dimensional weave armor in the heart part, for example by combining different interlock weaves, or interlock weave and multilayer weave weave, or different multilayer weave weaves. It is also possible to vary the weave of skin weave along the outer surface.

An exemplary embodiment of a fibrous structure according to the invention is now described. In this example, the weaving is performed on a Jacquard type loom.

FIG. 1 shows very schematically the weaving of a fibrous blank 100 from which a fibrous structure 200 can be extracted (FIG. 2) making it possible, after compacting and shaping, to obtain a fibrous reinforcement preform of a blade aeronautical engine. The fibrous blank 100 is obtained by three-dimensional weaving, or 3D weaving, or by multi-layer weaving made in a known manner by means of a Jacquard weaving loom on which a bundle of strand or strand wires 101 has been arranged. plurality of layers, the warp son being bonded by weft layers 102 also arranged in a plurality of layers, some frame layers including braids as hereinafter explained in detail. A detailed example of embodiment of a fiber preform intended to form the fibrous reinforcement of an aeronautical engine blade from a 3D woven fiber blank is described in detail in documents US 7 101 154, US 7 241 112 and US Pat. WO 2010/061140. The fibrous blank 100 is woven in the form of a strip extending generally in a direction X corresponding to the longitudinal direction of the blade to be produced. In the fibrous blank 100, the fibrous structure 200 has a variable thickness determined according to the longitudinal thickness and the profile of the blade of the blade to be produced. In its part intended to form a foot preform, the fibrous structure 200 has a portion of extra thickness 203 determined according to the thickness of the root of the blade to be produced. The fibrous structure 200 is extended by a portion of decreasing thickness 204 for forming Léchasse dawn and then a portion 205 for forming the blade of the blade. The portion 205 has in a direction perpendicular to the X direction a variable thickness profile between its edge 205a for forming the leading edge of the blade and its edge 205b intended to form the trailing edge of the blade to be realized .

The fibrous structure 200 is woven in one piece and must have, after cutting the nonwoven son of the blank 100, the shape and the almost final dimensions of the blade ("net shape"). For this purpose, in the thickness variation portions of the fibrous structure, as in the decreasing thickness portion 204, the decrease in thickness of the preform is achieved by progressively removing weft layers during weaving.

Once the weave of the fibrous structure 200 in the finished blank 100 is cut, the nonwoven son are cut. The fibrous structure 200 illustrated in FIG. 2 is then obtained and woven in one piece. The next step is to compact and shape the fibrous structure 200 to form a fiber preform ready to be densified. For this purpose, the fibrous structure is placed in a compacting and forming tool 400 (FIG. 5).

In accordance with the present invention, the fibrous structure 200 is placed in a shaped holding and conveying tool 300. As illustrated in FIG. 3, the tool 300 comprises a first shell 310 comprising at its center a first cavity 311 corresponding to part of the shape and dimensions of the blade to be produced, the cavity 311 being surrounded by a first contact plane 312. The first shell 310 further comprises an injection port 313 intended to allow the injection of a matrix precursor liquid composition in a fibrous preform. The tool 300 also comprises a second shell 320 comprising in its center a second cavity 321 corresponding in part to the shape and dimensions of the blade to be produced, the second cavity 321 being surrounded by a second contact plane 322 intended to cooperate with the first contact plane 312 of the first shell 310. The second shell further comprises a discharge port for cooperating with a pumping system.

The first and second shells may in particular be made of metal material such as aluminum for example.

The fibrous structure 200 is first positioned in the cavity 311 of the first shell 310, the second shell 320 is then placed on the first shell 310 to close the holding and transporting tool 300. Once the tool 300 closed as illustrated in Figure 4, the first and second shells are in a position called "assembly position", that is to say a position in which the first and second impressions 310, 320 are placed facing one another while the first and second contact planes 312 and 322 are also facing each other. In this configuration, the first and second cavities 310, 320 together define an internal volume 301 having the shape of the blade to be produced and in which the fibrous structure 200 is placed. In the example described here, the impression 311 is intended to forming the intrados side of the fibrous blade preform while the impression 321 is intended to form the extrados side of the blade preform.

In FIG. 5, the shaped holding and conveying tool 300 with the fibrous structure 200 inside thereof is placed in a compacting and forming tool 400. The tool 400 comprises a lower portion 410 on which rests the first shell 310 of the tool 300 and an upper portion 420 placed on the second shell 320 of the tool 300.

As shown in FIG. 6, the compacting and forming tooling 400 is subjected to the application of a compacting pressure PC applied for example by placing the tool 400 in a press (not shown in FIG. 6). The application of the pressure PC causes the first and second shells 310 and 320 to be brought together until the first and second contact planes 312 and 322 meet, which makes it possible both to compact the fibrous structure 200 according to a compaction rate determined to obtain a fiber rate also determined and shape the fibrous structure according to the profile of the blade to be manufactured. This gives a preform 500 having the shape of the blade to be produced.

The preform 500 thus protected in the shaped holding and transport tooling 300 can be transported without risk of deformation to an injection tool, for example a transfer molding tool (RTM). In Figures 7 and 8, the tool 300 is placed between a lower portion 610 and an upper portion 620 of an injection tool 600 (Figure 7). The lower part 610 and the upper part 620 of the tooling 600 are equipped with heating means (not shown in FIGS. 7 and 8).

Once the tooling 600 is closed, the blade is then molded by impregnating the preform 500 with a thermosetting resin which is polymerized by heat treatment (FIG. 8). For this purpose is used the well known method of injection molding or transfer called RTM ("Resin Transfer Molding"). According to the RTM method, a resin 530, for example a thermosetting resin, is injected via the injection port 313 of the first shell 310 into the internal space 301 defined between the two cavities 311 and 321 and occupied by the preform 500. The port 323 of the second shell 320 is connected to a discharge duct maintained under pressure (not shown in Figure 8). This configuration allows the establishment of a pressure gradient between the lower part of the preform 500 where the resin is injected and the upper part of the preform located near the port 323. In this way, the resin 530 injected at substantially the lower part of the preform will progressively impregnate all of the preform circulating therein to the discharge port 323 through which the surplus is discharged. Of course, the first and second shells 310 and 320 of the tool 300 may respectively comprise a plurality of injection ports and a plurality of discharge ports.

The resin used may be, for example, a temperature class epoxy resin 180 ° C (maximum temperature supported without loss of characteristics). Suitable resins for RTM methods are well known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of the temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the piece must be subjected. Once the resin is injected into the entire reinforcement, it is polymerized by heat treatment in accordance with the RTM method.

After the injection and the polymerization, the dawn is demolded. It can possibly undergo a post-baking cycle to improve its thermomechanical characteristics (increase of the glass transition temperature). In the end, the dawn is cut away to remove the excess resin and the chamfers are machined. No other machining is necessary since, the part being molded, it respects the required dimensions.

As illustrated in FIG. 13, a blade 700 formed of a fiber reinforcement densified by a matrix is obtained. The tool for holding and transporting 300 further comprises locking means in position able to maintain the first and second shells 310 and 320 according to their assembly position determined so as to allow the handling and transport of said tooling without relative displacement between the two assembled shells. These locking means in position are put in place or adjusted after the step of compacting and forming the fibrous structure. FIG. 9 illustrates a first example of locking means which corresponds to a clamping connection device 800 comprising two lugs 810 and 820 respectively fixed respectively to the first and second shells 310 and 320 of the tooling 300, the lugs 810 and 820. respectively comprising a light 811 and an orifice 821 in which is engaged a screw 840 cooperating with a nut 850 and thus making a clamping connection between the two tabs 810 and 820. The number of clamping device 800 present on the tooling 300 depends mainly on the size of the tooling. At least four clamping devices are preferably used, with a device placed on each side face of the tooling 300.

Another example of locking means in position is illustrated in FIG. 10 and corresponds to a lever-type lever closure device 900 comprising a lever 910 fixed to the shell 310 and provided with an articulated loop 911 and a tab hook 920 fixed on the shell 320 and intended to cooperate with the loop 911. The number of lever closure devices 900 present on the tool 300 depends mainly on the size of the tool. At least four lever closure devices are preferably used, with a device placed on each lateral face of the tooling 300.

Another example of locking means in position is illustrated in Figure 11 and corresponds to a clamping device 1000 comprising a screw 1010, the shell 320 having a bore 1030 for the passage of the screw 1010 which is tightened in a thread 1020 formed in the shell 310. The number of clamping device 100 present on the tool 300 depends mainly on the size of the tool. At least four clamping devices are preferably used, with a device present at each face of the tooling 300.

Any other locking means allowing a combination and locking in position of the first and second shells 310 and 320 in a direction normal to the plane of the shells so as not to deform the preform when closing the tool 300 can be used. Furthermore, in order to facilitate the transport of the tooling 300, the first and second shells 310 and 320 can be respectively equipped with a handle 314 and a handle 324 as shown in FIG. 12. In the example described here each shell includes a handle, which also makes it easy to transport the shells individually. However, the tool 300 may comprise only one handle disposed on one or the other of the shells 310 and 320. The invention finds application in the manufacture of turbomachine blades, in particular blades of fan of the aeronautical field. (

Claims (10)

1. A tool for holding and transporting (300) for a fibrous structure (200) or fibrous preform (500) comprising a first shell (310) comprising at its center a first cavity (311), the first cavity being surrounded by a first contact plane (312) and a second shell (320) comprising at its center a second cavity (321), the second cavity being surrounded by a second contact plane (322) intended to cooperate with the first plane of contact (312), the first and second indentations (311, 321) together defining an internal volume (301) having the shape of a part to be produced when the first and second shells (310, 320) are in an assembly position determined, the tooling further comprising locking means in position for holding the first and second shells (310, 320) in the assembly position determined so as to allow the handling and transport of said out illage without relative displacement between the two assembled shells. 2. Tooling according to claim 1, characterized in that the first shell (310) comprises at least one port (313) in communication with the internal volume (301) of the tool and in that the second shell (320) comprises at least one port (323) in communication with the internal volume (301) of the tool. 3. Tooling according to claim 1, characterized in that the first shell (310) comprises a plurality of ports in communication with the internal volume of the tool or in that the second shell (320) comprises a plurality of ports in communication with the internal volume of the tooling. 4. Tooling according to any one of claims 1 to 3, characterized in that it comprises a plurality of clamping connection devices (800; 1000). 5. Tooling according to claim 4, characterized in that it comprises at least four clamping connection devices (800; 1000), a clamping connection device being present on each lateral face of the tooling. 6. Tooling according to any one of claims 1 to 3, characterized in that it comprises a plurality of lever closure devices (900). 7. Tooling according to claim 6, characterized in that it comprises at least four lever closure devices (900), a lever closure device being present on each side face of the tooling. 8. Tooling according to any one of claims 1 to 7, characterized in that at least one of the two shells (310) is provided with a carrying handle (314). 9. A method of manufacturing a composite material part comprising the following steps: a) production of a fibrous structure (200) by three-dimensional or multilayer weaving, b) placement of the fibrous structure (200) in a compaction tool and forming (400), c) applying a compaction pressure (PC) to the fibrous structure (200) present in the compacting and forming tool (400) so as to obtain a fibrous preform (500) of the workpiece, d) transporting the fibrous preform (500) to an injection tool (600), e) placing the fibrous preform (500) in the injection tool (600), f) closing injection tooling (600), g) injecting a liquid composition (530) comprising at least one precursor of a matrix material in the fibrous preform (500), h) converting the liquid composition into a matrix in order to obtain a composite material part (700) comprising a reinforcement f characterized in that, prior to step b), the fibrous structure (200) is placed in a shaped holding and transporting tool (300) according to any one of claims 2 to 6 and in that the fiber preform (500) obtained after step c) is held in said holding and transporting tool (300) when performing steps d) to h). 10. The method of claim 9, characterized in that the composite material part corresponds to an aeronautical engine fan blade.