Method for producing parts made of composite material having an organic matrix

Abstract

The invention relates to a method (100) for producing a part made of composite material having an organic matrix, the method comprising the following steps: - arranging (110) a fibrous preform of the part to be produced in a mould comprising an impregnation chamber by resting a first face of the fibrous preform on a support surface of the impregnation chamber, the impregnation chamber being closed by a flexible membrane placed facing a second face of the fibrous preform, the flexible membrane separating the impregnation chamber from a compaction chamber; - injecting (120) a compaction fluid into the compaction chamber so as to apply a compaction pressure (Pcompaction) to the flexible membrane; - injecting (130) a resin into the impregnation chamber from a lateral face to the first face of the fibrous preform in a direction parallel to the surface of the membrane, so that the resin impregnates the fibrous preform and polymerises to form an organic matrix within the fibrous preform, the compaction pressure being maintained on the flexible membrane before and during the injection and polymerisation of the resin.

Description

[0001] Description

[0002] Title of the invention: Method for manufacturing parts made of organic matrix composite material

[0003] Technical Field

[0004] The present invention relates to the general field of manufacturing parts made of organic matrix composite material, in particular fan casing parts.

[0005] Prior art

[0006] These parts are usually made from a fiber preform impregnated with a resin which, when polymerizing, forms an organic matrix within the fiber preform.

[0007] The organic matrix can be formed by an RTM (Resin Transfer Molding) process. The preform is placed in a tool, such as a closed mold, into which a resin is injected into the preform, through one or more injection ports located opposite a side face of the preform. During the polymerization of the resin, a compaction pressure is applied through the injection ports. However, this pressure is not applied uniformly over the entire preform, which results in pressure losses between the resin injection ports and the rest of the preform.

[0008] To limit pressure loss, the organic matrix can be formed using the C-RTM (Compression Resin Transfer Molding) process. The resin is injected over the preform and the compaction pressure is applied to the entire top of the preform during resin polymerization. However, this process is not applicable to axisymmetric parts, as it is impossible to create a concentric rigid circular tool to apply the compaction pressure.

[0009] To overcome these two problems, the organic matrix can still be formed by the Polyflex process described in particular in document US2016297153. The Polyflex process consists of applying compaction pressure to the top of the preform using a flexible membrane located on top of the preform. A compaction fluid present between the flexible membrane and the tooling makes it possible to press the membrane onto the preform and to apply this compaction pressure so that the resin penetrates throughout the preform. However, when the compaction fluid exceeds the resin penetration front, a filling defect is created within the preform because the circulation of the resin is blocked. The resulting parts are partially dry, non-compliant and therefore rejected.

[0010] It is therefore desirable to have a manufacturing process for parts made of organic matrix composite material that guarantees the filling of the preform with the resin and its quality as well as the good polymerization of the resin.

[0011] Statement of the invention

[0012] The invention relates to a method for manufacturing a part made of organic matrix composite material comprising the following steps:

[0013] - the arrangement of a fibrous preform of the part to be manufactured in a mold comprising an impregnation chamber by resting a first face of the fibrous preform on a support surface of the impregnation chamber, the impregnation chamber being closed by a flexible membrane placed opposite a second face of the fibrous preform, said flexible membrane separating the impregnation chamber from a compaction chamber,

[0014] - injecting a compaction fluid into the compaction chamber so as to apply a compaction pressure on the flexible membrane, and

[0015] - injecting a resin into the impregnation chamber from a side face to the first face of the fiber preform in a direction parallel to the surface of the membrane so that the resin impregnates the fiber preform and polymerizes to form an organic matrix within the fiber preform, the compaction pressure being maintained on the flexible membrane before and during the injection and polymerization of the resin.

[0016] By applying the compaction pressure before injecting resin onto the flexible membrane, this allows the membrane to adapt to the geometry of the fiber preform to apply uniform pressure to it. It is therefore possible to manufacture axisymmetric casing-type parts with the method of the invention.

[0017] In addition, by maintaining a compaction pressure during injection and polymerization of the resin into the fiber preform, it is possible to ensure homogeneous filling of the preform without the circulation of the resin being blocked by the membrane and the compaction fluid while maintaining a uniform pressure over the entire fiber preform.

[0018] Thus, thanks to the process of the invention, the material health of the manufactured parts is improved.

[0019] According to a particular characteristic of the invention, the compaction pressure is variable during the injection and / or polymerization of the resin. The compaction pressure can vary between 1 bar and 30 bars.

[0020] For example, the compaction pressure can be increased during resin polymerization. This improves material health, particularly at the resin level, by reducing the risk of chemical porosities appearing.

[0021] According to another particular characteristic of the invention, the compaction fluid is an oil.

[0022] According to another particular characteristic of the invention, the method also comprises the demolding of the fiber preform after the polymerization of the resin.

[0023] According to another particular characteristic of the invention, the resin is a thermosetting epoxy resin.

[0024] According to another particular characteristic of the invention, the flexible membrane has a coefficient of thermal expansion of between 150 pm / m-°C and 300 pm / m-°C and a Shore A hardness of between 50 and 80. This allows the membrane to adapt to the geometry of the preform without deforming when the compaction pressure is applied.

[0025] According to another particular characteristic of the invention, the fiber preform is produced by three-dimensional weaving of fibers.

[0026] Thus, as the fiber preform is intended to form the fiber reinforcement of the part to be manufactured, the final part will have very good mechanical properties and a low risk of delamination.

[0027] Brief description of the drawings

[0028] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not limiting in nature.

[0029] [Fig. 1] Figure 1 schematically represents a manufacturing method according to one embodiment of the invention.

[0030] [Fig. 2A] Figure 2A shows, schematically and partially, an example mold allowing the manufacturing method of the invention to be implemented.

[0031] [Fig. 2B] Figure 2B shows, schematically and partially, the mold of Figure 2A during the injection of the resin into the impregnation chamber.

[0032] Description of the embodiments

[0033] The invention is described with reference to Figures 1, 2A and 2B, Figure 1 schematically representing a method 100 for manufacturing a part made of organic matrix composite material according to one embodiment of the invention and Figures 2A and 2B representing a mold making it possible to implement the method 100.

[0034] The method 100 first comprises the arrangement 110 of a fiber preform 210 of the part to be manufactured in a mold 200. The mold 200 comprises an impregnation chamber 240 and a compaction chamber 230 separated by a flexible membrane 220. The fiber preform 210 is intended to form the fiber reinforcement of the composite material part to be manufactured. It is considered here as the fiber structure of the composite material part to be manufactured, obtained by any technique or combination of textile constitution, arrangement and deformation techniques to arrange it in the mold 200.

[0035] The preform 210 can thus be produced at least in part by stacking layers or plies obtained by two-dimensional (2D) weaving. It can also be produced directly in a single piece by three-dimensional weaving. By "two-dimensional weaving" is meant here a conventional weaving method by which each weft thread passes from one side to the other of threads of a single warp layer or vice versa. By "three-dimensional weaving" is meant here a weaving by which warp threads pass through several layers of weft threads, or weft threads pass through several layers of warp threads.

[0036] The preform 210 can also be made at least in part by sheets of unidirectional (UD) fibers, which can be obtained by laying ribbons or by automatic fiber placement (AFP for “Automated Fiber Placement”), or by filament winding.

[0037] The preform 210 may be made from ceramic fibers or carbon fibers, or from a mixture of both. In particular, the preform 210 may be made from fibers made of the following materials: alumina, mullite, silica, an aluminosilicate, a borosilicate, silicon carbide, carbon, or a mixture of several of these materials. The preform 210 may comprise any type of glass fibers.

[0038] The preform 210 comprises a first face 211 and a second face 212 opposite the first face 211. The preform 210 is placed in the mold 200 by resting its first face 211 on a support surface 201 of the impregnation chamber 240. The flexible membrane 220 is opposite the second face 212 of the preform 210, and in the impregnation chamber 240, it is opposite the support surface 201 of the impregnation chamber 240. Then, a compaction fluid 260 is injected into the compaction chamber 230 so as to apply a compaction pressure P CO compaction on the flexible membrane 220 (step 120 of FIG. 1). The injection of the compaction fluid 260 can be done through an inlet port 231 of the mold 200 located opposite the flexible membrane 220 and opening into the compaction chamber 230. The compaction pressure Pcompaction thus applied makes it possible to deform the membrane 220 so that it comes to be pressed against the fiber preform 210.

[0039] Next, a resin 250 is injected into the compaction chamber 240 (step 130) from a lateral face 213 to the first face 211 of the fiber preform 210 in a direction X parallel to the surface of the membrane 220 so that the resin 250 impregnates the fiber preform 210 and polymerizes to form an organic matrix. The injection 130 of the resin 250 can be done via an inlet port 241 located opposite the lateral face 213 of the preform 210. During this step 130 of injection and polymerization of the resin 250, the compaction pressure Pcompaction is maintained on the flexible membrane 220.

[0040] Finally, the method 100 may comprise the demolding 140 of the fiber preform 210 after the polymerization of the resin 220.

[0041] The compaction pressure Pcompaction can be variable during the injection and polymerization of the resin 220. It varies for example between 1 bar and 30 bars.

[0042] The compaction fluid 260 is for example an oil.

[0043] Resin 220 is for example a thermosetting epoxy resin.

[0044] The flexible membrane 220 has a coefficient of thermal expansion of between 150 pm / m-°C and 300 pm / m-°C and a Shore A hardness of between 50 and 80. It is for example made of silicone, or an elastomer-type material. It can be reinforced with glass or polyester fibers. These examples of characteristics allow the flexible membrane 220 to be sufficiently flexible to adapt to the geometry of the preform 210 while remaining a minimum rigidity to withstand the compaction pressure Pcompaction applied by the compaction fluid 260. The expression “between ... and ...” must be understood as including the limits.

Claims

Claims

1. Method (100) for manufacturing a part made of organic matrix composite material comprising the following steps: - the arrangement (110) of a fibrous preform (210) of the part to be manufactured in a mold (200) comprising an impregnation chamber (240) by resting a first face (211) of the fibrous preform on a support surface (201) of the impregnation chamber, the impregnation chamber being closed by a flexible membrane (220) placed opposite a second face (212) of the fibrous preform, said flexible membrane separating the impregnation chamber from a compaction chamber (230), - injecting (120) a compaction fluid (260) into the compaction chamber so as to apply a compaction pressure (P CO impaction) on the flexible membrane, - injecting (130) a resin (250) into the impregnation chamber from a lateral face (213) to the first face of the fiber preform in a direction (X) parallel to the surface of the membrane so that the resin impregnates the fiber preform and polymerizes to form an organic matrix within the fiber preform, the compaction pressure being maintained on the flexible membrane before and during the injection, wherein the compaction pressure is further increased during the polymerization of the resin.

2. A manufacturing method according to claim 1, wherein the compaction pressure (P CO impaction) is variable during injection and polymerization of the resin.

3. A manufacturing method according to any one of claims 1 or 2, wherein the compaction fluid (260) is an oil.

4. A manufacturing method according to any one of claims 1 to 3, also comprising demolding (140) the fiber preform after polymerization of the resin.

5. A manufacturing method according to any one of claims 1 to 4, wherein the resin (250) is a thermosetting epoxy resin.

6. A manufacturing method according to any one of claims 1 to 5, wherein the flexible membrane (220) has a coefficient of thermal expansion of between 150 pm / m-°C and 300 pm / m-°C and a Shore A hardness of between 50 and 80.

7. A manufacturing method according to any one of claims 1 to 6, wherein the fibrous preform (210) is made by three-dimensional weaving of fibers.

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