Method for manufacturing a part made of composite material, in particular for an aircraft turbine engine, and associated device

Abstract

The invention relates to a method for manufacturing a part (2) made of composite material, in particular a part for an aircraft turbine engine, comprising the following steps: (a) manufacturing a fibrous blank (30) intended to form said part (2) made of composite material, (b) pre-heating a polymerisable mixture (7) containing a resin and a hardener, in order to dissolve the hardener in the resin, (c) injecting the polymerisable mixture (7) into at least one mould (6) containing the fibrous blank (30), (d) heating and densifying the fibrous blank (30) in order to polymerise the polymerisable mixture (7) and to impregnate the fibrous blank (30), and (e) demoulding the part made of composite material obtained in this way, wherein step (b) comprises a sub-step (b2) of dissolving the hardener in the resin using microwaves.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing composite material components, particularly for aircraft turbine engines, and an apparatus for carrying out this method. Background Technology

[0002] Prior art includes, in particular, the document US-A1-2004 / 0089975.

[0003] The use of composite materials is particularly advantageous in the aerospace industry because these materials offer interesting mechanical properties at a relatively low mass.

[0004] The method for manufacturing components made of composite materials, particularly for the aerospace industry, is the LCM (Liquid Composite Molding) method, which is well known to those skilled in the art. The manufacturing method of LCM can be resin transfer molding (RTM) or flexible injection molding (Polyflex).

[0005] This is a method for manufacturing components made from composite materials based on fibers impregnated with a so-called polymerizable resin-based mixture. This method is used, for example, to manufacture aerospace components, particularly those for aircraft turbine engines. Such components made from composite materials can be turbine engine impeller rings, housings, or gaskets.

[0006] LCM methods, which can be of the RTM or Polyflex type, consist of multiple consecutive steps.

[0007] First, the fibers are woven together to create a three-dimensional fiber preform, which is then cut into an approximate shape of the final part to be manufactured. The fiber preform is then placed in a closed mold. A liquid resin-based mixture is then injected, maintaining pressure on the injected mixture while the entire assembly polymerizes through heating.

[0008] The resulting part is removed from the mold and can be subjected to potential machining and / or joining operations.

[0009] Current injection lines include: - Injection cylinder, in which, after the vacuum degassing stage, the resin-based mixture is heated to a temperature between 80°C and 120°C; - A heater in which the solid hardener in the resin mixture is dissolved and the mixture reaches the optimal injection temperature (between 155°C and 170°C for PR520N type resin), i.e., the temperature at which the viscosity is minimum (less than 100 centipoise (cP)). - Press mold (or self-heating mold or oven), when the resin-based mixture has filled the cavity and the fiber preform placed in the mold is fully impregnated, heat the assembly to the curing temperature (between 170°C and 200°C for PR520N type resin); or in a variant called co-injection cycle, the resin-based mixture (especially in the case of AF191 type resin) can be injected into a so-called cooler mold containing the fiber preform (typically at a temperature between 80°C and 120°C). - A vacuum system is used to prevent air from remaining inside the mold cavity and forming pores and / or dry areas. Vacuum also helps to inject resin into the fibers that make up the reinforcement.

[0010] Prior to the injection molding step, the resin-based mixture is preheated in a known manner to make it as non-sticky as possible. Heating the mixture before injecting it into the mold is crucial. It is important that one of the components of the mixture (especially the hardener) is completely dissolved in the mixture (e.g., at a dissolution rate exceeding 85%) before it comes into contact with the fiber preform, as there is a risk that this component may be filtered into the fiber preform, and the mechanical properties of the resin will not be maintained during curing.

[0011] In the prior art, the resin-based mixture is preheated in a heater to dissolve the hardener, wherein the resin is heated to between approximately 90°C and 170°C throughout the heater.

[0012] There are different types of heaters.

[0013] For example, a thin-film heater could be used. The resin flows between two heated walls in a thin layer (approximately 0.2 mm). Heat exchange is optimized by exposing the thin resin layer to the heat flow. However, the flow rate of the resin that can be heated is limited, which restricts the maximum size of the part to be injected. For example, for resin PR520N, the resin injection time can be limited to approximately 30 minutes.

[0014] The heater can also consist of a series of stacked hot plates, with at least one serpentine channel hollowed out. The number of plates and the size of one or more channels determine the volume processed. The duration of resin residence in the heater is directly related to the flow rate and its volume. Controlling the temperature and residence time of the resin in the heater can be difficult to manage and may result in incomplete dissolution of the hardener or premature crosslinking (or in other words, polymerization) of the resin, which can lead to pipe blockage.

[0015] Alternatively, it can be a heat exchanger with a heat transfer fluid. This solution requires a secondary system for pumping and heating the heat transfer fluid. Therefore, this system may be more time-consuming, expensive, and difficult to install than previous solutions because it requires high-performance thermal seals.

[0016] Therefore, these well-known heaters are dynamic heat exchange systems with many parameters that must be kept under control: plate temperature, resin inlet temperature, residence time within the system, resin flow rate, and the resin's advance state at the system inlet (which can significantly affect its viscosity), etc. The risk of error can be significant, especially when the temperature and duration setpoints deviate from their nominal values ​​due to unforeseen reasons (such as injection piston failure, hose leaks, etc.). Consequently, controlling the dissolution of the hardener remains challenging. For example, in the case of co-injection cycles, the hardener may be difficult to dissolve in the so-called colder mold, particularly at temperatures between 80°C and 120°C. Therefore, it may be necessary to check whether the hardener has dissolved properly.

[0017] Additionally, the design of any type of heater can limit certain parameters, such as the injection flow rate. If the injection flow rate of the resin mixture is limited by the heater capacity, the resin injection time may be longer.

[0018] Additionally, depending on the type of heater, a certain amount of resin-containing mixture may be lost at the end of the injection process. This loss is typically taken into account during the manufacturing process.

[0019] In these different contexts, it is of interest to propose a solution for optimizing and simplifying the manufacture of composite material components, particularly those for aircraft turbine engines. Summary of the Invention

[0020] This invention provides a simple, effective and economical solution to at least some of the above-mentioned problems.

[0021] Therefore, the present invention relates to a method for manufacturing components made of composite materials, particularly components for aircraft turbine engines, the method comprising the following steps: (a) Manufacturing a fiber preform intended to form the component made of a composite material. (b) Preheating the polymerizable mixture containing resin and hardener to dissolve the hardener in the resin. (c) Injecting the polymerizable mixture into at least one mold containing a fiber preform. (d) Heating and densifying the fiber preform to polymerize the polymerizable mixture and impregnate the fiber preform, and (e) Demolding the part made from the composite material obtained in this way.

[0022] According to the present invention, step (b) includes sub-step (b2): dissolving the hardener in the resin by using microwaves.

[0023] Therefore, this solution enables the achievement of the aforementioned objectives. Generally, the method of this invention simplifies and optimizes the manufacture of parts made of composite materials, particularly through liquid casting (e.g., RTM or Polyflex). To achieve this, microwaves are used to dissolve the hardener.

[0024] It has been observed that microwaves provide the specific energy required to dissolve the solid particles of the hardener contained in a polymerizable mixture. Indeed, the typical polarization of polymerizable mixtures (particularly epoxy resins) is advantageous in this invention because microwaves can exert pressure on the molecular structure, and the resulting molecular vibrations generate heat, allowing the hardener (particularly the solid particles constituting the hardener) to dissolve in the polymerizable mixture. The energy provided by the microwaves is consumed in the phase transition of the hardener (e.g., from solid to liquid phase), but is insufficient to initiate a crosslinking (or in other words, polymerization) reaction in the resin.

[0025] The method of the present invention simplifies the manufacture of components and the systems that use them. The heater described above, which restricts the flow rate of the mixture and thus limits the size of the composite component to be manufactured, is no longer required.

[0026] The method of the present invention also minimizes the amount of resin lost at the end of the process for manufacturing the part. This allows for an increase in injection rate, thereby enabling the manufacture of large parts.

[0027] According to the invention, step (b) further includes a sub-step (b3) of cooling the polymerizable mixture, for example, to room temperature, and / or a sub-step (b4) of stabilizing the temperature of the polymerizable mixture. The cooling sub-step (b3) may occur after the sub-step (b2) of dissolving the hardener, and the sub-step (b4) may occur after either sub-step (b2) or sub-step (b3). This allows any polymerization reaction of the resin to be stopped (or even not initiated) before the polymerizable mixture is injected into a mold and / or any other encapsulation container.

[0028] The manufacturing method according to the invention may include one or more of the following features, either independently or in combination: - In sub-step (b2), microwaves are emitted by at least one fixed or movable source; - In sub-step (b2), the polymerizable mixture is contained in a vessel that is fixed or movable relative to the microwaves, for example, rotating; - Prior to step (b), the resin is in a liquid state and the hardener is in a solid state; --The hardener is dispersed in a liquid resin, especially pre-dispersed in a liquid resin; - The polymerizable mixture is either stationary or movable relative to the container; - The polymerizable mixture can move relative to a stationary container; - The method further includes a step (i) of adjusting the polymerizable mixture, which is performed before or simultaneously with step (c); - The vessel is at least one delivery pipe for conveying the polymerizable mixture obtained at the end of step (b) to the at least one mold and / or at least one encapsulation container; --The method further includes a step (ii) of heating the polymerizable mixture before step (i) and / or before step (c); --For example, in step (ii), the polymerizable mixture obtained in sub-step (b2) is heated with a temperature gradient; this increases the viscosity of the polymerizable mixture to be injected in step (c); --The polymerizable mixture obtained in sub-step (b2) is heated by a heat source, preferably a heat source that is far from and different from the microwave source used in sub-step (b2); -- Apply microwaves directly to the at least one delivery pipe; --Sub-step (b4) is carried out by separating the polymerizable mixture obtained in sub-step (b2) or sub-step (b3) for example via an insulated (or remote) hose. - Microwaves generate power between 100 watts and 3000 watts, preferably between 100 watts and 1500 watts; - The maximum duration of microwave application is approximately 5 minutes, which is, for example, between 1 second and 90 seconds, preferably approximately 30 seconds; - Step (b) includes a sub-step (b1): preheating the resin of the polymerizable mixture to a preheating temperature; this sub-step (b1) is performed before the sub-step (b2) of dissolving the hardener; --The polymerizable mixture obtained in sub-step (b2) is placed in a cooling zone, for example via a delivery pipe or any other element, and is configured to maintain the temperature without triggering or accelerating the polymerization of the resin in the polymerizable mixture; --At the end of sub-step (b2), the polymerizable mixture is cooled to at least 1°C below the predetermined outlet temperature of the polymerizable mixture; --The hardener is completely or partially dissolved; - "Complete dissolution" means that the dissolution rate of the hardener can exceed 80% or 85%; --The complete dissolution rate of the hardener is between 85% and 100%; - Partial dissolution of the hardener includes a dissolution rate between 50% and 85%; -- Sub-step (b2) has a dissolution rate greater than 80% or 85%; -In particular, in step (b1), the preheating temperature of the resin is between 80°C and 120°C; --In particular, in step (d), the heating temperature in the mold is between 80°C and 200°C, preferably between 160°C and 200°C, especially when the polymerizable mixture contains a polyepoxy resin (such as PR520N resin). --The resin that can polymerize the mixture is a thermosetting material; --The polymerizable resins do not contain thermoplastic materials; --Resins include polyepoxides (or epoxides), polyimides, or polybismaleimides; --Polymerizable blends include PR520N resin sold by Solvay, 2896 resin sold by 3M, or RTM250ST resin sold by Hexcel. - Polyepoxy resins based on bisphenol F diglycidyl ether (abbreviated as DGEBF), especially when the polymerizable mixture contains PR520N resin, or based on bisphenol A diglycidyl ether (abbreviated as DGEBA), especially when the polymerizable mixture contains 2896 resin; --The hardener in the polymerizable mixture is a crosslinking agent, which triggers the polymerizable and irreversible hardening of the resin under the action of heat; --The hardener is selected from 9,9-bis(4-amino-3-chlorophenyl)fluorene (abbreviated as CAF), 1,12-dodecanoic acid (abbreviated as DDA), 4,4'-diamino-diphenyl sulfone (abbreviated as DDS) and hexamethylenediamine (abbreviated as HDMA). --Components made of composite materials are aerospace composite material components, such as turbine engine blade components (e.g., fan rotor blades, or turbine engine stator blades), housings (e.g., fan housings), or gaskets (e.g., fan gaskets).

[0029] The present invention also relates to an apparatus for carrying out a method for manufacturing a component made of a composite material according to one of the features of the invention, the apparatus comprising: - The area used to manufacture the fiber preform for step (a). - A pretreatment zone for pretreating the polymerizable mixture, the pretreatment zone being configured to dissolve the hardener in the resin in step (b), and -The at least one mold is used to receive the fiber preform and inject the polymerizable mixture for steps (c) and (d).

[0030] According to the invention, the pretreatment region includes at least one microwave source configured to perform a sub-step (b2) of dissolving a hardener in a resin.

[0031] According to the invention, the pretreatment zone includes a cooling zone for performing a sub-step (b3) of cooling the polymerizable mixture.

[0032] The device according to the invention may include one or more of the following features employed in isolation from or in combination with each other: - The microwave source is a microwave oven; - The pretreatment area includes a preheating device, such as an oven or autoclave, which is configured to perform a sub-step (b1) of preheating the resin of the polymerizable mixture. - The cooling area includes cooling devices selected from water baths, cooling chambers, air cooling tunnels, heat exchangers, annealing furnaces, and liquid nitrogen systems; --The delivery pipes or any other components of the polymerizable mixture obtained in sub-step (b2) are arranged in a cooling zone and configured to maintain the temperature without triggering or accelerating the polymerization of the resin in the polymerizable mixture; --The device includes a conditioning region for conditioning the polymerizable mixture, the conditioning region being configured to store the polymerizable mixture obtained at the end of step (b) for subsequent use, for example, for injection into the at least one mold and / or the at least one encapsulation container; --The conditioning area includes at least one encapsulation container, such as a tube or syringe.

[0033] The device may include any element capable of performing the steps of the methods described above. Attached Figure Description

[0034] Other features and advantages will become apparent from the following description of non-limiting embodiments of the invention with reference to the accompanying drawings, in which: Figure 1 This is a block diagram illustrating the steps in a method for manufacturing a component made of composite materials according to the present invention; Figure 2 It is used for implementation Figure 1 A very schematic diagram of a first example of a manufacturing method according to the apparatus of the present invention, wherein a polymerizable mixture is injected into a mold; Figure 3 It shows Figure 2 A very schematic diagram of a portion of the device shown; Figure 4 schematically shown Figure 2 or Figure 3 An example of the arrangement of microwave sources in a device; Figure 5 It shows Figure 2 Another example of the arrangement of microwave sources in the device shown; Figure 6 Is to implement Figure 1 A very schematic diagram of a second example of an apparatus for a manufacturing method, wherein a polymerizable mixture is conveyed into one or more encapsulation containers; Figure 7 yes Figure 6 A schematic diagram of a variation of the device shown; Figure 8 Is to implement Figure 1 A very schematic diagram of a third example of an apparatus for a manufacturing method, wherein a polymerizable mixture is injected into a mold and also conveyed to a packaging container.

[0035] Elements that have the same function in different embodiments have the same reference numerals in the drawings. Detailed Implementation

[0036] This invention relates to a method for manufacturing a component 2 (particularly for an aircraft turbine engine) made of composite materials, the method comprising a plurality of sequential steps: (a) Manufacturing a fiber preform 30 intended to form component 2, (b) The polymerizable mixture 7 containing resin (preferably liquid) and hardener (preferably solid) is preheated to dissolve the hardener in the resin. (c) Injecting the polymerizable mixture 7 into at least one mold 6 containing the fiber preform 30, (d) Heating and densifying the fiber preform 30 to polymerize the polymerizable mixture 7 and impregnate the fiber preform 30, and (e) Demold the part 2 made of the composite material obtained in this way.

[0037] The method may further include step (i): adjusting the polymerizable mixture 7. This step (i) may be performed before or simultaneously with step (c). The polymerizable mixture 7 encapsulated in step (i) may form a semi-finished product.

[0038] Figure 1 The steps in the method for manufacturing part 2 are outlined, wherein optional steps are shown in dashed lines.

[0039] exist Figures 2 to 8 A non-limiting example of device 1 that allows this method to be implemented is shown in the figure.

[0040] Component 2 made of composite materials can be an aerospace composite component, such as a turbine engine blade component (e.g., a rotor blade of a fan, or a stator blade of a turbine engine rectifier), a turbine engine housing (e.g., a fan housing), a turbine engine gasket (e.g., a fan gasket that holds the fan blade in place when the turbine engine is stationary), or any other component of a turbine engine or aircraft.

[0041] Component 2, made of composite material, may include a polymer matrix (or resin) and a fiber preform 30 (or fiber reinforcement) embedded in the matrix and densified to form a fiber preform. In other words, the fiber preform may be embedded in the resin. "Fiber preform" refers to an intermediate component, particularly an intermediate component between the fiber preform 30 and the final component 2.

[0042] Composite materials can be organic matrix materials (OMMs). OMMs are used to replace components made of metallic materials, particularly in certain parts of turbine engines (such as the aforementioned blades and casings). Furthermore, the use of OMMs often helps optimize the performance of turbine engines and aircraft, especially by significantly reducing harmful emissions (CO, CO2, NO) through improved turbine engine efficiency and reduced overall turbine engine weight. x wait).

[0043] In step (a), the fiber preform 30 can be manufactured by three-dimensionally braiding fibers or by stacking multiple fiber layers or layups. For example, three-dimensional fiber braiding can be interlocking braiding. "Interlocking" braiding refers to a braid in which each layer of weft connects multiple layers of warp to all the threads of a single weft column that have the same movement in the braiding plane.

[0044] Step (a) may also include, for example, cutting the fiber blank 30 using pressurized water jet to obtain the final geometry of the part 2 to be obtained.

[0045] The fiber blank 30 obtained in step (a) can be placed in the cavity of the mold 6.

[0046] The fiber preform 30 can be made of carbon, glass, aramid, ceramic, or Kevlar. ® It is made of fibers, a mixture of at least two of these fibers, or any other fibers.

[0047] Prior to step (b), a polymerizable mixture 7 can be provided by mixing the resin (preferably liquid) and the hardener (preferably solid).

[0048] Preferably, prior to step (b), the hardener can be dispersed in a liquid resin.

[0049] The resin (or matrix, once the resin has been densified) of polymerizable mixture 7 can be a thermosetting material. Preferably, the resin can include polyepoxide (or epoxide), polyimide, or polybismaleimide.

[0050] The resin of polymerizable mixture 7 may not contain thermoplastic materials.

[0051] The polymerizable mixture 7 may include PR520N resin sold by Solvay, 2896 resin sold by 3M, or RTM250ST resin sold by Hexcel.

[0052] Advantageously, the resin can be a polyepoxy resin, such as PR520N resin sold by Solvay, which can be based on bisphenol F diglycidyl ether (abbreviated as DGEBF), or 2896 resin sold by 3M, which can be based on bisphenol A diglycidyl ether (abbreviated as DGEBA).

[0053] The hardener in polymerizable mixture 7 can be a crosslinking agent, which triggers the polymerization and hardening of the resin under heat, especially irreversible hardening.

[0054] Preferably, the hardener may be selected from 9,9-bis(4-amino-3-chlorophenyl)fluorene (abbreviated as CAF), 1,12-dodecanoic acid (abbreviated as DDA), 4,4'-diamino-diphenyl sulfone (abbreviated as DDS) and hexamethylenediamine (abbreviated as HDMA).

[0055] The polymerizable blend 7 may also contain at least one or more other components, such as at least one additional filler. Preferably, the filler may comprise less than 30% by weight of the polymer blend, or at most 10% by weight for an elastomeric filler. The purpose is to improve certain physicochemical and / or mechanical properties of component 2. For example, the additional filler in the polymerizable blend 7 may be, but is not limited to, an elastomer, mineral, ceramic, or metal.

[0056] To achieve optimal results, especially in terms of the mechanical properties of the cured resin, the hardener must be dissolved in the resin before being injected into mold 6.

[0057] Therefore, one of the features of the present invention is that the step (b) of preheating the polymerizable mixture 7 includes a sub-step (b2): dissolving the hardener in the resin using microwaves. This optimizes and simplifies the dissolution of the hardener without inducing crosslinking of the resin, while avoiding the use of complex, expensive, and time-consuming heater systems.

[0058] The hardener can be completely or partially dissolved in the resin. Complete dissolution of the hardener may involve a dissolution rate exceeding 80% or 85%. Preferably, the complete dissolution rate of the hardener is between 85% and 100%. Partial dissolution of the hardener may include a dissolution rate between 50% and 85%.

[0059] The method may also include a step (ii) of heating the polymerizable mixture 7, which is performed before step (i) and / or before step (c). This allows the polymerizable mixture to be encapsulated and stored or injected at a temperature suitable for step (i) or step (c).

[0060] For example, in step (ii), the polymerizable mixture 7 obtained in sub-step (b2) can be heated with a temperature gradient. This increases the viscosity of the polymerizable mixture 7 to be injected in step (c). Heating the polymerizable mixture 7 after sub-step (b2) can be carried out by a heat source, preferably located away from and different from the microwave source used in sub-step (b2).

[0061] Another feature of the invention is that the method further includes a sub-step (b3) for cooling the polymerizable mixture 7 and / or a sub-step (b4) for stabilizing the temperature of the polymerizable mixture 7. The cooling sub-step (b3) may be performed after the hardener has dissolved, and sub-steps (b2) and (b4) may be performed after sub-step (b2) or sub-step (b3).

[0062] Cooling the polymerizable mixture and / or maintaining a stable temperature of the polymerizable mixture allows the resin to avoid polymerization or stop polymerization, while keeping the hardener dissolved in the polymerizable mixture. In particular, temperature stabilization can be an alternative method for gradually cooling or maintaining the temperature of the polymerizable mixture at the outlet of sub-step (b2).

[0063] Sub-step (b4) can be carried out, for example, by separating the polymerizable mixture 7 obtained in sub-step (b2) or sub-step (b3) via an adiabatic (or remote) tube.

[0064] Then, according to step (c), the polymerizable mixture 7 obtained at the end of step (b) (preferably at the end of sub-step (b2)) can be directly injected into one or more molds 6, in particular without passing through any other preheating element, such as the heater described in the background art above.

[0065] Alternatively, the polymerizable mixture 7 obtained at the end of step (b) can be directly adjusted (or pre-adjusted) according to step (i), preferably at the end of sub-step (b2). This can be done in at least one encapsulation container 72. One or more containers 72 can be a cylinder 720 and / or a syringe 722. The adjusted polymerizable mixture 7 can be reused at a later date, for example, by injection into one or more molds 6.

[0066] According to another variation, the polymerizable mixture 7 obtained at the end of step (b) (preferably at the end of sub-step (b2)) can be injected into one or more molds 6 and also encapsulated in one or more encapsulation containers 72. This can be done simultaneously or not simultaneously.

[0067] Microwaves can be generated and applied by at least one source 44 (or otherwise referred to as a generator), such as a microwave oven, a magnetron, or any other device for generating and applying / emitting microwaves.

[0068] The microwave source 44 can be fixed or movable, especially relative to the device 1 and / or the polymerizable mixture 7.

[0069] Depending on the type of microwave source 44, the microwaves can generate power between 100 watts and 3000 watts. For example, the microwaves can generate power between 100 watts and 1500 watts. Preferably, the power is approximately 800 watts.

[0070] Microwaves can be applied for up to 5 minutes. For example, microwaves can be applied for a duration of 1 second to 90 seconds; preferably, the duration is about 30 seconds.

[0071] Microwaves can be emitted in sub-step (b2) by the at least one fixed or movable source 44. For example, microwaves can be emitted by a fixed or movable microwave source 44, particularly in device 1 (as described above).

[0072] "Modible" refers to microwaves in dynamic motion (such as rotational, linear, or helical motion).

[0073] The polymerizable mixture 7 may be contained in a vessel 70, which is fixed or movable (e.g., rotating) relative to the microwaves in sub-step (b2).

[0074] The vessel 70 can be a glass jar or any other container suitable for microwave heating. Preferably, the vessel 70 can be at least one delivery pipe located in, for example, the piping system 5 (described below) of device 1. Thus, microwaves can be applied directly to this delivery pipe, which in particular enables the polymerizable mixture 7 containing the dissolved hardener to be continuously delivered to the mold 6 and / or container 72.

[0075] The polymerizable mixture 7 can be stationary or movable relative to the vessel. For example, the vessel 70 can be placed on a support that allows the polymerizable mixture to move.

[0076] Advantageously, the polymerizable mixture 7 can be movable, while the container 70 is fixed. Figures 3 to 5 Therefore, the polymerizable mixture 7 can move around in the vessel 70, for example, in the form of a conveyor line. The movement of the polymerizable mixture can be controlled by adjusting the flow rate and / or pressure within the vessel.

[0077] This application will now describe examples of the operational modes of sub-step (b2) of the method of the present invention in a non-limiting manner.

[0078] First, a sample of a polymerizable mixture containing PR520N resin and weighing approximately 20 grams (g) is placed in a glass jar.

[0079] Next, place the sample and glass jar in a commercial microwave oven to dissolve the hardener contained in the sample. For this, apply 800 watts of power for approximately 30 seconds. At the end of this dissolution (or heating) cycle, allow the dissolved sample to cool to room temperature (e.g., approximately 25°C).

[0080] At the end of sub-step (b2), the physical state of the dissolved sample is characterized by measuring the glass transition temperature and enthalpy (or heat capacity by mass) to characterize the dissolution of the hardener. To achieve this, DSC (Differential Scanning Calorimetry) tests are performed on the cooled dissolved sample.

[0081] Therefore, the glass transition temperature (Tg) of the dissolved sample (i.e., after microwave treatment) is higher than that of the undissolved sample (i.e., in its initial state, completely undissolved and uncrosslinked). The glass transition temperature of the initially undissolved sample is approximately -23°C, while that of the dissolved sample is approximately +11°C.

[0082] In addition, in quantities less than 5 J.g -1 The residual enthalpy of dissolution of the dissolved sample was measured at a value of (joules / unit mass (grams)), while the enthalpy of the crosslinking reaction of the sample was between 280 J / g. -1 Up to 300 J.g -1 The initial standard values ​​are between. Because the enthalpy of the dissolved sample is lower than the enthalpy of the crosslinking reaction, the sample is dissolved after passing through microwaves without initiating crosslinking of the resin.

[0083] This allows for the determination of the dissolution rate of the sample after microwave treatment (which is greater than 80%), while preventing the resin crosslinking reaction from starting.

[0084] The dissolution rate can be measured and obtained by calorimetry, such as modulated differential scanning calorimetry (mDSC). For this purpose, the energy required to dissolve the hardener in the initially undissolved, unheated resin is compared with the energy required to dissolve the hardener in the microwave-heated resin of the dissolved sample.

[0085] The step (b) of preheating the polymerizable mixture may include a sub-step (b1): preheating the resin of the polymerizable mixture 7 to a preheating temperature. This sub-step (b1) is performed prior to the sub-step (b2) involving the dissolution of the hardener.

[0086] The preheating temperature of the resin can be between 80°C and 120°C.

[0087] As described above, step (b) may include sub-step (b3): ​​cooling the polymerizable mixture 7, for example, to room temperature (e.g., between 18°C ​​and 25°C). The cooling sub-step (b3) is performed after sub-step (b2) for dissolving the hardener. Sub-step (b3) may be performed before step (c) and / or step (i) and / or sub-step (b4).

[0088] Then, according to step (c), the polymerizable mixture 7 obtained at the end of sub-step (b3) can be directly injected into one or more molds 6, as in Figure 3 As shown in a non-restrictive manner.

[0089] Alternatively, the polymerizable mixture 7 obtained at the end of sub-step (b3) can be directly adjusted (or pre-adjusted) according to step (i), as in Figure 6 and Figure 7 This is shown in a non-limiting manner. This can be done in one or more encapsulation containers 72, as described above in a non-limiting manner.

[0090] The adjusted polymerizable mixture 7 can be reused at a later date, for example, by injection into one or more molds 6. In this case, the polymerizable mixture 7 containing the dissolved hardener can be injected directly into one or more molds 6 without having to dissolve the hardener again for each mold 6 (i.e., step (b)).

[0091] The polymerizable mixture 7 packaged according to step (i) can be stored at a predetermined temperature (e.g., ambient temperature) that allows the hardener dissolved in the resin to be stored after the polymerization reaction has stopped. The ambient temperature can be between 18°C ​​and 25°C.

[0092] The polymerizable mixture 7 obtained in sub-step (b2) can be placed in the cooling zone 8 of the apparatus 1 (described below) and configured to maintain the temperature without triggering or accelerating the polymerization of the resin in the polymerizable mixture 7. For example, the polymerizable mixture 7 can be arranged via a delivery pipe or any other element capable of maintaining the temperature of the polymerizable mixture.

[0093] Advantageously, the polymerizable mixture 7 can be cooled to at least 1°C below the predetermined outlet temperature of the polymerizable mixture at the end of sub-step (b2). This can be done at room temperature.

[0094] According to another variation, the polymerizable mixture 7 obtained at the end of sub-step (b3) can be injected into one or more molds 6 and also encapsulated in one or more encapsulation containers 72, as in Figure 8 As shown in the example. This can be done simultaneously or not simultaneously.

[0095] In step (d), the heating temperature in mold 6 can be between 80°C and 200°C. Preferably, the heating temperature can be between 160°C and 200°C, especially when the polymerizable mixture contains PR520N resin.

[0096] Advantageously, steps (b), (c) and / or (d) of the method can be performed under vacuum, for example by a vacuum system (not shown in the figure).

[0097] This application will now describe an apparatus 1 for implementing the method described above.

[0098] refer to Figure 2 Device 1 includes: -A region (3) for manufacturing the fiber preform 30, for performing step (a) for manufacturing the fiber preform 30. - A pretreatment zone 4 for the polymerizable mixture, configured to perform step (b) of dissolving the hardener in the resin, and - The at least one mold 6, which is used to receive the fiber preform 30 and inject a polymerizable mixture to carry out the steps (c) of injecting the polymerizable mixture (particularly containing a hardener that is completely or partially dissolved in the resin) into the mold 6 and the steps (d) of heating and densifying the fiber preform 30.

[0099] The apparatus 1 may include a piping system 5 for conveying the polymerizable mixture 7 from one part of the apparatus 1 to another part. For example, the piping system 5 may include at least one conveying conduit for conveying the polymerizable mixture 7 containing a hardener wholly or partially dissolved in the resin from the pretreatment zone 4 (particularly from the source 44) to one or more molds 6 and / or one or more encapsulation containers 72.

[0100] As described above, the polymerizable mixture 7 can be contained in a vessel 70, specifically for carrying out step (b). This vessel 70 can be a so-called delivery conduit of the piping system 5, such as... Figures 6 to 8 As shown.

[0101] One feature of the present invention is that the pretreatment region 4 includes at least one microwave source 44 configured to perform sub-step (b2): dissolving a hardener (e.g., completely or partially) in the resin. For example, the microwave source 44 may be a commercial microwave oven. Figures 6 to 8 As shown, microwave source 44 can be directly applied to a delivery pipe containing polymerizable mixture 7.

[0102] exist Figure 3 In the example shown, the pretreatment area 4 may include an injection device 40 (or otherwise referred to as an injection device) designed to contain and inject (e.g., via a piston) a polymerizable mixture 7.

[0103] As shown by the example, in Figures 3 to 8 In this process, the polymerizable mixture 7 can be injected from the injection device 40 into a vessel 70 (such as a delivery tube or pipe) to dissolve the hardener by microwave. Therefore, the polymerizable mixture 7 is movable, particularly within the stationary vessel 70, and flows in the direction indicated by the dashed arrow. The polymerizable mixture 7 containing the hardener that has been completely dissolved by microwave can then be supplied via one or more pipes of the piping system 5 to one or more molds 6 and / or one or more encapsulation containers 72.

[0104] refer to Figure 3 , Figure 4 and Figures 6 to 8 Source 44 may extend around the vessel 70 containing the polymerizable mixture 7. For example, the polymerizable mixture 7 may be contained in the vessel 70 at a rate between 20 cubic centimeters per minute (cm³ / min). 3 Flow rates range from 1000 cubic centimeters per minute to 2000 cubic centimeters per minute.

[0105] In another variation, source 44 can be directly connected to vessel 70 to dissolve the hardening agent, see reference. Figure 5 .

[0106] The pretreatment zone 4 may include a preheating device 42 configured to perform sub-step (b1): preheating the resin of the polymerizable mixture. For example, the preheating device 42 may be an oven or an autoclave.

[0107] The pretreatment zone 4 may include a cooling zone 46 for performing sub-step (b3): ​​cooling the polymerizable mixture.

[0108] Cooling zone 4 may include cooling devices selected from water baths, cooling chambers, air cooling tunnels, heat exchangers, annealing furnaces, and liquid nitrogen systems.

[0109] The delivery pipes or any other components of the polymerizable mixture 7, which includes sub-step (b2), may be arranged in the cooling zone 4 and configured to maintain the temperature without triggering or accelerating the polymerization of the resin in the polymerizable mixture 7.

[0110] The device 1 may include a conditioning region 8 for the polymerizable mixture 7, which is configured to store the polymerizable mixture 7 obtained at the end of step (b) for subsequent use, such as for injection into one or more molds 6 and / or one or more encapsulation containers 72.

[0111] Adjustment area 8 may include one or more encapsulation containers 72, such as handle 720 or syringe 722. Figures 6 to 8 ).

[0112] Device 1 may include or be connected to remote control and command devices, such as computerized devices.

[0113] The device 1 may include a vacuum system for generating a vacuum in the device 1, particularly in the area of ​​the component requiring a vacuum.

Claims

1. A method for manufacturing a component (2) made of composite materials, particularly for a component used in an aircraft turbine engine, the method comprising the following steps: (a) Manufacturing a fiber preform (30) intended to form the component (2) made of composite material. (b) The polymerizable mixture (7) containing resin and hardener is preheated to dissolve the hardener in the resin. (c) Injecting the polymerizable mixture (7) into at least one mold (6) containing the fiber preform (30), (d) Heating and densifying the fiber preform (30) to polymerize the polymerizable mixture (7) and impregnate the fiber preform (30), and (e) Demolding the part made from the composite material obtained in this manner. Characterized by the fact that step (b) comprises a sub-step (b2): dissolving the hardener in the resin using microwaves, and wherein, Step (b) further includes a sub-step (b3) of cooling the polymerizable mixture (7) for example to room temperature, and / or a sub-step (b4) of stabilizing the temperature of the polymerizable mixture (7), wherein the cooling sub-step (b3) is performed after the sub-step (b2) of dissolving the hardener, and the sub-step (b4) is performed after either sub-step (b2) or sub-step (b3).

2. The manufacturing method according to claim 1, characterized in that, In sub-step (b2), the microwaves are emitted by at least one fixed or movable source.

3. The manufacturing method according to claim 1 or 2, characterized in that, Prior to step (b), the resin is in a liquid state and the hardener is in a solid state.

4. The manufacturing method according to any one of claims 1 to 3, characterized in that, In sub-step (b2), the polymerizable mixture (7) is contained in a vessel (70) which is fixed or movable relative to the microwave, for example, rotating.

5. The manufacturing method according to the preceding claim, characterized in that, The polymerizable mixture (7) is movable relative to the fixed container (70).

6. The manufacturing method according to any one of the preceding claims, characterized in that, The method further includes step (i) of adjusting the polymerizable mixture (7), which is performed before or simultaneously with step (c).

7. The manufacturing method according to claims 5 and 6, characterized in that, The vessel (70) is a delivery conduit for conveying the polymerizable mixture (7) obtained at the end of step (b) to at least one mold (6) and / or packaging container (72).

8. The manufacturing method according to any one of claims 5 to 7, characterized in that, The method further includes a step (ii) of heating the polymerizable mixture (7) before step (i) and / or before step (c).

9. The manufacturing method according to any one of the preceding claims, characterized in that, The microwave generates power between 100 watts and 3000 watts, preferably between 100 watts and 1500 watts.

10. The manufacturing method according to any one of the preceding claims, characterized in that, The maximum duration of the applied microwave is about 5 minutes, which is, for example, between 1 second and 90 seconds, preferably about 30 seconds.

11. The manufacturing method according to any one of the preceding claims, characterized in that, Step (b) includes a sub-step (b1): preheating the resin of the polymerizable mixture (7) to a preheating temperature; this sub-step (b1) is performed before the sub-step (b2) of dissolving the hardener.

12. The manufacturing method according to claim 11, characterized in that, Specifically, in step (b1), the preheating temperature of the resin is between 80°C and 120°C.

13. The manufacturing method according to any one of the preceding claims, characterized in that, The dissolution in sub-step (b2) is partial dissolution, with a dissolution rate between 50% and 85%.

14. An apparatus (1) for carrying out a method for manufacturing a component (2) made of composite material according to any one of the preceding claims, the apparatus (1) comprising: -Area (3) for manufacturing fiber preforms (30) to perform step (a). - A pretreatment zone (4) for pretreating the polymerizable mixture (7), the pretreatment zone being configured to dissolve the hardener in the resin in step (b), and - The at least one mold (6) is used to receive the fiber preform (30) and inject the polymerizable mixture (7) for steps (c) and (d). The pretreatment region (4) is characterized in that it includes at least one microwave source (44) configured to perform a sub-step (b2) of dissolving the hardener in the resin, and wherein, The pretreatment zone (4) includes a cooling zone (46) for performing a sub-step (b3) of cooling the polymerizable mixture.

15. The device according to the preceding claim in conjunction with claim 10, characterized in that, The pretreatment zone (4) includes a preheating device (42), such as an oven or autoclave, which is configured to perform a sub-step (b1) of preheating the resin of the polymerizable mixture.

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