FR3046564A1 - LIFTING AND TRANSPORT TOOLS FOR A FIBROUS PREFORM AND METHOD FOR MANUFACTURING A COMPOSITE MATERIAL PART - Google Patents

Abstract

A hoisting and conveying tool (300) for a structure (200) includes a frame (310) formed of at least two posts (311, 312) extending in a first direction and a cross member (313) holding the two spaced apart from each other. The amounts delimit between them an internal space (301) in which extends a plurality of substantially flat strips (320), each strap (320) being removably or removably mounted between the two uprights (311, 312).

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 composition comprising minus a precursor of a matrix material 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 mat rice. Extraction of the preform from the compacting and forming tooling as well as transporting the preform to the tooling enabling the injection of a precursor liquid composition of a matrix material such as a resin in 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 a lifting and transporting tool for a fibrous structure or preform comprising a frame formed of at least two uprights extending in a first direction and a crosspiece holding the two spaced apart amounts one of the other, said amounts defining between them an internal space in which extends a plurality of flat strips, each strap being removably or removably mounted between the two uprights.

Thus, the tool of the invention proposes a solution that allows to support, lift and transport flat a fibrous preform with balanced supports which are located below the preform. Extraction of the preform of a compacting and forming tool is thus greatly facilitated compared to manual extraction because the preform is difficult to access in the cavity of the compaction and forming tool. In addition, the tool of the invention avoids any manual manipulation directly on the preform and thus avoid the risk of deformation of the latter.

According to one aspect of the lifting and transporting tool of the invention, each strap has a thickness of between 0.1 mm and 0.5 mm.

According to another aspect of the lifting and transporting tool of the invention, each strap is made of a thermoplastic material such as polyethylene (LDPE) or silicone.

According to one embodiment of the lifting and transporting tool of the invention, the strips are fixed to the frame uprights by reversible retaining devices.

According to another embodiment of the lifting and transporting tool of the invention, the strips are slidably mounted on the uprights of the frame. The invention also proposes 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 compacting and forming tools c) applying a compaction pressure to the fibrous structure present in the compaction and forming tool so as to obtain a fibrous preform of the workpiece, d) extracting the fibrous preform from the compaction tooling and forming, 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 composition comprising at least one precursor of a matrix material in the fibrous preform, i) converting the liquid composition into a matrix so as to obtain a piece of composite material e comprising a fiber reinforcement densified by a matrix, characterized in that during the realization of step b), a lifting and transporting tool according to the invention is interposed between the fibrous structure and a lower portion of the tooling compacting and forming and in that the fiber preform obtained after step c) is based on said lifting and transporting tool during the realization of steps d) to f), the lifting and transporting tool being removed before the completion of step g). The extraction of the preform of a compacting and forming tool during step d) is thus greatly facilitated compared to a manual extraction because the preform is difficult to access in the cavity of the compaction and forming tooling. .

Steps b), d), e) and f) are performed without any manual intervention directly on the fiber preform, which avoids the risk of deformation of the fiber preform, and with a good repeatability of the steps.

The tool straps being mounted therein in a removable or retractable manner, they can be easily released from the preform after its placement in the injection molding tool without manual intervention on the preform.

The manufacturing range is not complicated by the use of the tooling of the invention.

The piece of composite material may in particular correspond to a turbine engine fan blade or aeronautical engine.

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 a schematic perspective view showing a lifting and carrying tool according to an embodiment of the invention and placing the fibrous structure of Fig. 2 thereon; Figure 4 is a schematic perspective view showing the placement of the lifting and transporting tool of Figure 3 in a compaction tool and forming; Figure 5 shows a compaction and forming operation with the tools of Figure 4; Figure 6 shows the extraction of a fibrous preform from the compaction and forming tool of Figures 4 and 5; Figure 7 is a schematic perspective view showing the placement of the fiber preform carried by the lifting and transporting tool of Figure 6 in an injection tool; Figures 8 and 9 show respectively the removal of the fibrous preform on the injection tool of Figure 7 and the removal of the straps of the lifting and transport tooling; Figure 10 shows a first embodiment of removable retaining means for the straps of the lifting and transporting tool of Figure 3; Figure 11 shows a second embodiment of removable retaining means for the straps of the lifting and transporting tool of Figure 3; Figure 12 shows the closure of the injection tooling of Figures 8 and 9; Fig. 13 shows an operation of injecting a liquid matrix precursor composition into a fibrous preform; Figure 14 is a schematic perspective view of a turbomachine blade of composite material obtained according to a manufacturing method of the invention; FIGS. 15 and 16 are diagrammatic perspective views of a lifting and transporting tool according to another embodiment of the invention, FIGS. 15 and 16 respectively showing the removal of the fibrous preform on the tooling, injection of Figure 7 and removal of the straps of the lifting and transport tooling.

DETAILED DESCRIPTION OF EMBODIMENTS The invention generally applies to the production of parts made of composite material for a turbomachine, the part being made from a fiber preform in which a precursor liquid composition of a matrix 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 compaction and forming tool 400 (FIG. 4).

In accordance with the present invention, structure 200 is placed on a lifting and transporting tool 300. As illustrated in FIG. 3, the lifting and transporting tool 300 comprises a frame 310 formed of at least two uprights 311 and 312 extending in a first direction Da corresponding to the longitudinal direction in which the fibrous structure 200 extends and a cross member 313 maintaining the two amounts 311 and 312 spaced apart from each other. The amounts 311 and 312 define between them an internal space 301 in which extends a plurality of flat strips 320 in a second direction perpendicular to the first direction Da. Each strap 320 is removably or slidably mounted between the two uprights as will be described hereinafter in detail. Strips 320 are preferably made of a flexible thermoplastic material, translucent and resistant such as polyethylene (LDPE) or silicone. They preferably have a thickness of between 0.1 mm and 0.5 mm.

In FIG. 4, the compacting and forming tooling 400 comprises a lower portion 410 comprising at its center an impression 411 corresponding in part to the shape and the dimensions of the fibrous preform of blade to be produced, the impression 411 being surrounded by a contact plane 412 and an upper portion 420 having in its center an imprint 421 corresponding in part to the shape and dimensions of the fibrous preform of blade to be produced, the imprint 421 being surrounded by a plane of contact 422 intended to cooperate with the contact plane 412 of the lower part 410. In the example described here, the impression 411 is intended to form the intrados side of the fibrous blade preform while the impression 421 is intended to form the extrados side of the dawn preform.

As illustrated in FIG. 4, the lifting and transporting tool 300 is interposed between the lower part 410 of the compaction and forming tool 400 and the fibrous structure 200 so that the structure 200 rests on the straps 320. the frame 310 of the tool 300 being positioned on the contact plane 412 of the lower part 410. In order to allow the closure of the tooling 400 and the forming and compacting of the fibrous structure in the tooling 400, the upper part 420 comprises a groove 423 for housing the frame 310 in the tool 400 without hindering its closure and the approach of the contact plane 412 and 422 during compaction.

Once closed, as shown in FIG. 5, 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. Figure 5). The application of the PC pressure makes it possible both to compact the fibrous structure 200 according to a determined compaction ratio in order to obtain a fiber content that is also determined and to shape the fibrous structure according to the profile of the blade to be manufactured. . The preform is also dried in tooling 400.

As illustrated in FIG. 6, a preform 500 having the shape of the blade to be produced is then obtained. The preform 500 is extracted from the lower portion 410 of the compacting and forming tool 400 by vertical lifting thereof by means of the lifting and transporting tooling 300. Thanks to the flexible strips 320 and their distribution on the entire axial length of the preform 500, it is possible to lift the latter from its housing in the lower part 410 without deforming it.

The preform 500 can thus be transported without risk of deformation to an injection molding tool (RTM). In FIGS. 7 and 8, the preform 500 is deposited with the lifting and conveying tooling 300 in a lower mold 610 of an injection tooling 600, for example a tooling of the injection molding type (FIG. 10). The lower mold 610 has in its center an impression 611 corresponding in part to the shape and dimensions of the blade to be produced, the cavity 611 being surrounded by a sealing plane 612. The lower mold 610 further comprises a port 613 for the injection of a resin.

Once the preform 500 positioned in the footprint 611 of the lower mold 610, the straps 320 are removed to release the preform of the lifting and transporting tool 300. In the example described here, the straps 320 are removed in sliding the latter outside the tool 300 as shown in Figure 9. For this purpose, the amount 312 of the tool 300 comprises slots 3120 in which are engaged first ends 320a of the strips 320, each slot 3120 comprising a device (not shown in Figure 9) for alternately sounding (for example by pinching) and release the ends 320a of the strips 320. In addition, the amount 311 of the tool 300 comprises through slots 3121 each comprising a device (Not shown in Figure 9) alternately to sound (for example by pinching) and release the second 320b ends of the strips 320. The slots 3121 through Throughout the amount 311, it is possible to pull on the ends 320b of the strips 320 to extract them from the internal space 301 of the tool 300 and to release the preform 500 which then rests directly on the impression 611. of the lower mold 610.

According to a first embodiment illustrated in FIG. 10, the strips 320 are retained between the uprights 311 and 312 by tongs 330 and 331, respectively disposed on the outside of the uprights 311 and 312. During the withdrawal of the strips 320, the tongs 330 and 331 are removed so as to release the strips 320 and allow their extraction from the internal space 301 as shown in FIG. 9.

According to a second embodiment illustrated in FIG. 11, the straps 320 are retained on the side of the upright 312 by abutments 340 and by clamps 331 on the side of the upright 311. During removal of the straps 320, the tongs 331 are removed in such a way that release the strips 320 and allow their extraction from the internal space 301 by pulling on the stops 340.

As illustrated in FIG. 12, the frame 310 of the lifting and transporting tool 300 is in turn removed from the lower mold 610. The injection molding tool 600 is then closed with an upper mold 620 which includes in its center a cavity 621 corresponding in part to the shape and dimensions of the blade to be produced, the cavity 621 being surrounded by a sealing plane 622 which cooperates with the sealing plane 612 of the lower mold 610. The mold upper 620 further comprises a port 623 for pressurizing the injected resin.

Once the tooling 600 is closed, the blade is then molded by impregnating the preform 500 with a thermosetting resin that is polymerized by heat treatment (FIG. 13). 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 613 into the internal space defined between the two cavities 611 and 621 and occupied by the preform 500. The port 623 is connected to a discharge duct maintained under pressure (not shown in Figure 13). 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 623. In this way, the resin 10 injected at substantially the lower part of the preform will gradually impregnate all of the preform circulating therein to the discharge port 623 through which the surplus is discharged. Of course, the injection molding tool may 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. 14, a blade 700 formed of a fiber reinforcement densified by a matrix is obtained.

Figures 15 and 16 illustrate an alternative embodiment of the lifting and transporting tool according to the invention. In FIG. 15, a hoisting and conveying tool 800 differs from the tool 300 in that the frame 810 comprises uprights 811 and 812 longer than the uprights 311 and 312 of the tooling 300, on the one hand, and in that, on the other hand, the uprights 811 and 812 respectively comprise rails 8120 and 8110 in which sliders 820 similar to the straps 320 already described can slide. Thus, during its transportation and its handling, the fiber preform 500 rests on the strips 820 which are arranged in a lower part of the tooling 800 as illustrated in FIG. 15. Once the preform 500 has been positioned in the impression 611 610, the strips 820 are slidably moved in the rails 8120 and 8110 to an upper portion of the tool 800 near the cross member 813 to release the preform 500 of the tool 800 as shown in Figure 16. The invention finds application in the manufacture of turbomachine blades, in particular fan blades of the aeronautical field.

Claims (7)

A lifting and transporting tool (300) for a structure (200) or fibrous preform (500) comprising a frame (310) formed of at least two posts (311, 312) extending in a first direction and a crosspiece (313) maintaining the two amounts spaced apart from each other, said amounts delimiting between them an internal space (301) in which extends a plurality of substantially planar strips (320), each strap (320) being mounted removably or removably between the two uprights (311, 312). 2. Tooling according to claim 1, characterized in that each strap (320) has a thickness of between 0.1 mm and 0.5 mm. 3. Tooling according to claim 1 or 2, characterized in that each strap (320) is made of a thermoplastic material. 4. Tooling according to any one of claims 1 to 3, characterized in that each strap (320) is fixed to the uprights (311, 312) of the frame (310) by reversible retaining devices. 5. Tooling according to any one of claims 1 to 3, characterized in that each strap (320) is slidably mounted on the uprights (311, 312) of the frame (310). 6. 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 compacting tool and forming (400), c) applying a compacting pressure (PC) to the fibrous structure (200) present in the compacting and forming tool (300) so as to obtain a fibrous preform (500) of the workpiece, d) extracting the fibrous preform (500) from the compaction and forming tool (400), e) transporting the fibrous preform (500) to an injection tool (600), f ) placing the fiber preform (500) in the injection tooling (600), g) closing the injection tool (600), h) injecting a liquid composition (530) comprising at least one precursor of a matrix material in the fibrous preform (500), i) converting the liquid composition into matrix so as to obtain a composite material part (700) comprising a matrix-densified fiber reinforcement, characterized in that during the realization of step b), a lifting and transporting tool (300) according to the any one of claims 1 to 5 is interposed between the fibrous structure (200) and a lower portion (410) of the compacting and forming tool (400) and in that the fibrous preform (500) obtained after the step c) rests on said lifting and transporting tool (300) when performing steps d) to f), the lifting and transporting tool being removed before performing step g). 7. Method according to claim 6, characterized in that the composite material part corresponds to an aeronautical engine fan blade.