Manufacturing an acoustic component with easy mold removal

Abstract

Manufacturing an Acoustic Component with Facilitated Mold Removal. The invention relates to a method for manufacturing an acoustic component comprising a plurality of hollow acoustic elements having a shape that gradually narrows between a base and a top, said method comprising: - positioning and shaping a blank (12) in a shaping tool (500) so as to obtain an acoustic component (120), - opening the shaping tool (500) so that a first face (120a) of the acoustic component (120) is free and a second face (120b) of the acoustic component (120) remains in contact with the shaping tool (500), - spraying a first fluid (601; 701) onto the second face (120a) of the acoustic component (120), - injecting a second fluid (801) onto the first face (120b) of the acoustic component (120) through channels (523) trained in shaping tooling (500).Figure for the abridged version: Fig. 5.

Description

Title of the invention: Manufacturing of an acoustic component with facilitated mold removal technical field

[0001] The present invention relates to the general field of acoustic attenuation panels. It relates more particularly to acoustic attenuation panels used to reduce noise produced in aircraft engines such as gas turbines or exhausts thereof. Previous technique

[0002] Acoustic attenuation panels typically consist of a plate or skin with an acoustic surface permeable to the acoustic waves to be attenuated and a solid reflective plate or skin, referred to as the "closing plate or skin," with at least one multicellular body disposed between these two skins. The multicellular body is generally made up of a set of partitions forming a rib network and delimiting a plurality of cells. As is well known, such panels form Helmholtz-type resonators that attenuate acoustic waves within a certain frequency range.

[0003] It is also well known to place hollow acoustic elements, for example open truncated cones, within the cells of the multicellular body. The set of hollow acoustic elements forms an acoustic component, which is assembled with the multicellular body and with the acoustic skin. These hollow acoustic elements make it possible to process low frequencies without resorting to an excessively thick multicellular body. Such acoustic attenuation panels are described, for example, in documents WO 2023089267 A1, WO 2023079233 A1, and WO 2023135381 A1

[0004] The acoustic component is conventionally produced by thermoforming in a forming tool. Because the acoustic component has a complex shape and very thin profiles, removing it from the forming tool is a delicate and time-consuming process. Furthermore, there is a significant risk of damaging the acoustic component during its removal from the forming tool. Description of the invention

[0005] In order to remedy the aforementioned drawbacks, the present invention proposes a method of removing the forming tooling that is quick and easy to implement, with a low risk of damage to the acoustic component.

[0006] To this end, the invention proposes a method for manufacturing an acoustic component comprising a plurality of hollow acoustic elements having a shape that gradually narrows between a base and a top, said method comprising:

[0007] - the positioning of a draft between a first part and a second part complementary to a shaping tool kit,

[0008] - the shaping of said draft into an acoustic component by means of a close approximation of the first and second parts of the shaping tooling,

[0009] - the spacing of the first and second parts of the forming tooling so that a first face of the acoustic component is at a distance from the first part of the shaping tooling and that a second face of the acoustic component opposite the first face remains in contact with the second part of the shaping tooling,

[0010] - the removal of the acoustic component from the shaping tooling,

[0011] the process being characterized in that it comprises, before the removal of the tooling formatting:

[0012] - the projection of a first fluid onto the first face of the acoustic component, the first fluid exhibiting a temperature lower than the temperature of the acoustic component,

[0013] - the injection of a second fluid onto the second face of the acoustic component to through channels formed in the second part of the shaping tooling, the injection of the second fluid begins during or after the start of the projection of the first fluid.

[0014] The injection of the first fluid produces a thermal shock on the first face of the acoustic component, thereby initiating its separation from the second part of the forming mold. Furthermore, the injection of the first fluid cools the acoustic component. The injection of the second fluid completes the separation initiated by the injection of the first fluid and allows the acoustic component to be ejected without damage.

[0015] The application of the first fluid and the injection of the second fluid work together to allow the removal of the acoustic component. Indeed, the application of the first fluid alone is insufficient for a smooth and satisfactory detachment of the acoustic component, and the injection of the second fluid without prior detachment could damage the acoustic component. Thus, the application of the first fluid and the injection of the second fluid combined allow for easy and rapid removal of the acoustic component without damaging it.

[0016] According to a particular aspect of the invention, the projection of the first fluid is completed before the injection of the second fluid.

[0017] Thus, it is ensured that the acoustic component is properly and uniformly detached before proceeding with the injection of the second fluid, which further limits the risk of damage.

[0018] According to another particular aspect of the invention, the projection of the first fluid is carried out at least partly simultaneously with the injection of the second fluid.

[0019] By injecting the second fluid before projecting the first fluid, it is possible to carry out the process more quickly.

[0020] According to a first embodiment of the invention, the projection of the first fluid is carried out by means of one or more fluid projection devices arranged between the first part and the second part of the shaping tooling and projecting the first fluid towards the second face of the acoustic component.

[0021] Thus, the fluid spraying device(s) can be positioned directly opposite the first face of the acoustic component, enabling very rapid cooling of a large portion of the first face. Consequently, a satisfactory thermal shock is quickly achieved across the entire first face. This method also has the advantage of allowing for very precise fluid spraying.

[0022] The fluid spraying device(s) are maintained at a non-zero distance from the first and second parts of the tooling. In particular, the fluid spraying device(s) do not pass through the first or second part of the tooling. In other words, the path of the first fluid is devoid of any portions passing through the first part of the forming tooling. The path of the first fluid within the fluid spraying device remains at a non-zero distance from the first part of the forming tooling. Thus, the fluid temperature is easier to control, as it is less affected by the temperature of the first and second parts.

[0023] In particular, at least one fluid spraying device disposed between the first and second parts of the forming tooling can be carried by a removable arm, for example, a robotic arm. This removable arm can also be used to remove the acoustic component from the forming tooling after the injection of the second fluid.

[0024] According to a second embodiment of the invention, the projection of the first fluid is carried out by means of one or more fluid projection devices arranged around the shaping tooling and projecting the first fluid into the space delimited between the first part and the second part of the shaping tooling so as to diffuse the first fluid into said space.

[0025] This method has the advantage of being very easy to implement at a low cost. Automating such a method is also particularly easy to implement.

[0026] According to a third embodiment of the invention, the projection of the first fluid is carried out by injecting the first fluid onto the first face of the component Acoustic fluid is transmitted through channels formed in the first part of the forming tool. However, this embodiment is not preferred. Indeed, it is preferable that the first fluid does not pass through either the first or second part of the forming tool, in order to better control its temperature.

[0027] According to a particular aspect of the invention, the first part of the forming tooling comprises a plurality of molding cavities and the second part of the forming tooling comprises a plurality of teeth.

[0028] According to another particular aspect of the invention, the first part of the shaping tooling comprises a plurality of teeth and the second part of the shaping tooling comprises a plurality of molding cavities.

[0029] Preferably, the second part of the tooling is positioned below the first part of the tooling, so that the weight of the acoustic component attracts said acoustic component towards the second part of the tooling. The risk of the acoustic component falling unintentionally is thus limited, and the repeatability of the process of the invention is improved.

[0030] According to a particular aspect of the invention, the first fluid and the second fluid are air.

[0031] Thus, the first and second fluids are easy to implement and inexpensive. Furthermore, there is no need to provide a specific system for fluid recovery or for limiting pollution.

[0032] According to a particular aspect of the invention, the blank is made of thermoplastic material, the shaping tooling having a temperature greater than or equal to the glass transition or melting temperature of the thermoplastic material of the blank when shaping said blank into an acoustic component.

[0033] The process is then a thermoforming or thermo-stamping process. Thus, the initial fluid can be injected at room temperature while still achieving a satisfactory thermal shock. Furthermore, injecting the initial fluid cools the acoustic component, bringing it closer to room temperature and thus facilitating its handling as it exits the forming mold.

[0034] The invention further relates to a method for manufacturing a sound-attenuating panel comprising:

[0035] - the manufacture of an acoustic component according to the process described above,

[0036] - the assembly of the acoustic component with a multicellular body so that the hollow acoustic elements are arranged in the cells of the multicellular body,

[0037] - the assembly of the acoustic component with an acoustic skin such that the Acoustic skin covers the bases of hollow acoustic elements. Brief description of the drawings

[0038] [Fig.1] Fig.1 is a schematic exploded perspective view of an acoustic panel.

[0039] [Fig.2] Fig.2 is a schematic cross-sectional view of the acoustic panel of the [Fig.l].

[0040] [Fig.3] Fig.3 is a schematic cross-sectional view of a shaping tool in an open position in which a draft is positioned.

[0041] [Fig.4] Fig.4 is a schematic cross-sectional view of the shaping tooling of the [Fig.3] in the closed position having formed an acoustic component.

[0042] [Fig. 5] Fig. 5 is a schematic cross-sectional view of the shaping tooling figures 3 and 4 in open position to allow the projection of a first fluid according to a first embodiment of the invention.

[0043] [Fig.6] Fig.6 is a schematic cross-sectional view of the shaping tooling figures 3 and 4 in open position to allow the projection of a first fluid according to a second embodiment of the invention.

[0044] [Fig.7] Fig.7 is a schematic partial cross-sectional view of the tooling in the shape of figures 3 and 4 during the injection of a second fluid. Description of the implementation methods

[0045] Figures 1 and 2 illustrate an example of an acoustic panel 100 comprising in order an opening acoustic skin 110, an acoustic component 120 comprising a plurality of hollow acoustic elements 121, a multicellular body 130 and a closing skin 140.

[0046] The acoustic skin with opening 110 has the function of allowing the sound waves to be attenuated to pass through the acoustic panel 100. For this purpose, the acoustic skin with opening 110 comprises a plurality of perforations 111, as illustrated in Figures 1 and 2. At least one perforation 111 of the acoustic skin 110 corresponds to each cell of the multicellular body 130 and to each hollow acoustic element 121 of the acoustic component 120. The acoustic skin with opening 110 can have a thickness of between 1 mm and 5 mm, for example 1.5 mm.

[0047] The acoustic skin with an aperture of 110 can be produced in a well-known manner by stamping, by automated fiber placement (AFP), or by automated tape laying (ATL). Other processes can also be used to manufacture the acoustic skin with an aperture of 110, such as manual lay-up. The acoustic skin with an aperture of 110 can be made of a thermoplastic material, for example, a thermoplastic matrix composite material comprising fibers. The fibers can be carbon, glass, or aramid. The matrix thermoplastic can be made for example from polyaryletherketone (PAEK), polyetherketoneketone (PEKK), polyetherimide (PEI), polyphenylene sulfide (PPS), polyethersulfone (PESU), polyphenylsulfone (PPSU) or polycarbonate (PC).

[0048] The closing skin 140 corresponds to a solid surface designed to reflect sound waves entering the acoustic panel 100. The closing skin 140 may be a constituent element of the acoustic panel, as in the example described here, or correspond to a structure of an object, for example, an aircraft engine. In the latter case, the acoustic panel 100 does not have a closing skin and is mounted directly onto the structure of the object.

[0049] The closure skin 140 can be produced in a well-known manner by stamping, by automated fiber placement (AFP), or by automated tape laying (ATL). Other processes can also be used to manufacture the closure skin 140.

[0050] The closing skin 140 may be made of a composite material comprising fibers, for example, a composite material based on carbon fibers impregnated with a thermoplastic or thermosetting resin. The closing skin 140 may not comprise fibers. The closing skin 140 may comprise all the types of fibers and all the types of matrix described previously for the acoustic opening skin 110. The acoustic skin 140 may also comprise other types of fibers and other types of matrix than those described previously.

[0051] The multicellular body 130 comprises a plurality of septa 131 which form a network of ribs, thus delimiting cells 132. Each septum 131 extends between a superior edge 131a and a inferior edge 131b. The superior edges 131a of the septa 131 define a superior assembly face 130a of the multicellular body 130. The inferior edges 131b of the septa 131 define a inferior assembly face 130b of the multicellular body 130. Thus, the cells 132 extend from the superior assembly face 130a to the inferior assembly face 130b of the multicellular body 130.

[0052] The heights Hnodes cells 132 of the multicellular body 130 are chosen so as to obtain treatment of the frequencies of interest according to the use which will be made of the acoustic panel 100.

[0053] In the example illustrated in Figures 1 and 2, the cells 132 of the multicellular body 130 have a square cross-section. Of course, it does not depart from the scope of the invention if the cells 132 of the multicellular body 130 have a hexagonal, rectangular, round, or other cross-section.

[0054] The multicellular body 130 can be made of polymer, composite, or metallic material, by additive manufacturing or by conventional means. The multicellular body 130 can also be made in a well-known manner from thermoplastic material by injection molding, bending, or tube assembly. The thermoplastic material can be reinforced with short or long fibers. The multicellular body 130 may be unreinforced.

[0055] The acoustic component 120 comprises a plurality of hollow acoustic elements 121, each having a shape that gradually narrows between a base 121a and a top 121b. The hollow acoustic elements 121 are connected to each other by one or more connecting edges 122. The connecting edges 122 comprise an upper face 122a, located on the same plane as the bases 121a of the hollow acoustic elements 121, and a lower face 122b opposite the upper face 122a. The bases 121a of the hollow acoustic elements 121 and the upper faces 122a of the edges 122 define an upper assembly face 120a of the acoustic component 120. The upper assembly face 120a of the acoustic component 120 is intended to be assembled in contact with the acoustic skin 110. The lower faces 122b of the edges 122 define a lower assembly face 120b of the acoustic component 120.The lower assembly face 120b of the acoustic component 120 is intended to be assembled in contact with the multicellular body 130. More specifically, the lower assembly face 120b of the acoustic component 120 is intended to be assembled in contact with the upper assembly face 130a of the multicellular body 130.

[0056] In the example shown in Figures 1 and 2, the hollow acoustic elements 121 have a pyramidal shape. However, it does not depart from the scope of the invention if the hollow acoustic elements have, for example, a conical, spiral, or funnel shape. In the example shown in Figures 1 and 2, the hollow acoustic elements 121 exhibit symmetry. However, it does not depart from the scope of the invention if the hollow acoustic elements are asymmetrical.

[0057] The hollow acoustic elements 121 may have a wall thickness of between 0.25 mm and 2 mm. Preferably, the hollow acoustic elements 121 have a thickness of less than 1 mm, for example, between 0.3 mm and 0.5 mm. Preferably, the base 121a of the hollow acoustic elements 121 is contained within a circle with a diameter of between 5 mm and 50 mm. For example, the base 121a of the hollow acoustic elements 121 is contained within a circle with a diameter of 20 mm.

[0058] Preferably, the height H^o of the hollow acoustic elements 121 is between 5 mm and 100 mm. For example, the height H^o of the hollow acoustic elements 121 is 20 mm. The height Hi20 of the hollow acoustic elements 121 is less than the height Hi30 of the cells 132 of the multicellular body 130.

[0059] In the example illustrated in Figures 1 and 2, the acoustic panel 100 comprises only a single multicellular body and a single acoustic component. It is, of course, still within the scope of the invention if the acoustic panel comprises several superimposed multicellular bodies. It is also still within the scope of the invention if the acoustic panel comprises several acoustic components. The acoustic panel may also include intermediate acoustic skins delimiting different layers of said acoustic panel.

[0060] According to the invention, the acoustic component 120 is produced by shaping in a shaping tool.

[0061] Figures 3 to 7 illustrate an example of forming tooling 500 for shaping the acoustic component 120.

[0062] The forming tool 500 comprises a first part 510 and a second part 520 arranged opposite each other. The first part 510 and the second part 520 may be made of metal. The first part 510 and the second part 520 are movable relative to each other along a direction of movement D. The forming tool 500 may further comprise side clamps 530 for holding the blank 12 of the acoustic component 120 between the first part 510 and the second part 520 of the forming tool 500.

[0063] In the example illustrated in Figures 3 to 7, the first part 510 of the forming tool 500 comprises a plurality of teeth 511. The teeth 511 are connected to each other. In the example illustrated in Figures 3 to 7, the second part 520 of the forming tool 500 comprises a plurality of molding cavities 521. The molding cavities 521 are intended to cooperate with the teeth 511 of the first part 510 of the forming tool 500. The molding cavities 521 and the teeth 511 have a shape corresponding to the shape of the hollow acoustic elements 121 of the acoustic component 120 to be produced. Thus, in the example illustrated in figures 3 to 7, the first part 510 of the forming tool 500 is a male part and the second part 520 of the forming tool 500 is a female part.However, we do not depart from the scope of the invention if the first part of the shaping tooling is the female part and the second part of the shaping tooling is the male part.

[0064] The teeth 511 of the male part 510 of the forming tool 500 are separated from each other by a network of hollows 512. The molding cavities 521 of the female part 520 of the forming tool 500 are separated from each other by a network of protrusions 522. Thus, the network of hollows 512 of the male part 510 is intended to cooperate with the network of protrusions 522 of the female part 520. The The network of hollows 512 of the male part 510 and the network of prominences 522 of the female part 520 have a shape corresponding to the shape of the connecting edges 122 of the acoustic component 120 to be produced.

[0065] The temperature of the first part 510 and the second part 520 of the forming tool 500 is controllable in a well-known manner. The temperature of the first and second parts 510, 520 of the forming tool 500 can be controlled by means of an induction system, heat transfer fluid channels, or a forced-air system. The forming tool 500 may also include auxiliary heating means for heating the blank 12 even when it is not in contact with the first and second parts 510, 520 of the forming tool 500.

[0066] As illustrated in [Fig. 3], a blank 12 is first placed in the forming tool 500 in the open position. The blank 12 is thus positioned between the first part 510 and the second part 520. Said blank 12 can be held by means of side clamps 530.

[0067] The blank 12 is preferably made of thermoplastic material. The thermoplastic material may be, in particular but not exclusively, selected from the following materials: polyaryletherketones (PAEKs) such as polyetheretherketone (PEEK) and polyetherketoneketone (PEKK), polyetherimides (PEIs), polycarbonate (PC), polyphenylene sulfide (PPS), polyethersulfone (PESU), polyphenylsulfone (PPSU), and polysulfones (PSUs). The thermoplastic material may be filled with particles and / or fibers, or be unfilled with particles and / or fibers.

[0068] As illustrated in [Fig. 4], the first part 510 and the second part 520 are brought together so as to place the shaping tool 500 in the closed position. The first part 510 and the second part 520 are then brought into contact with the blank 12 so as to deform it into an acoustic component 120.

[0069] When the forming tool 500 is closed, the acoustic component 120 thus comprises a first face 120c in contact with the first part 510 of the forming tool 500 and a second face 120d in contact with the second part 520 of the forming tool 500. The first face 120c is opposite the second face 120d of the acoustic component 120.

[0070] In the example illustrated in Figures 3 to 7, the first face 120c of the acoustic component 120 corresponds to the upper assembly face 120a of the acoustic component 120 described previously, and the second face 120d of the acoustic component 120 corresponds to the lower assembly face 120b of the acoustic component 120 described previously. However, if the first part of the forming tool is the female part of the forming tool and the second part of the forming tooling is the male part of the forming tooling, the first face 120c of the acoustic component 120 then corresponds to the lower assembly face 120b of the acoustic component 120 described previously and the second face 120d of the acoustic component 120 then corresponds to the upper assembly face 120a of the acoustic component 120 described previously.

[0071] Preferably, the blank 12 is shaped by thermoforming or thermostamping. Thus, before the shaping step, the blank 12 is preferably exposed to a temperature below the glass transition temperature, if it is an amorphous material, or the melting temperature, if it is a semi-crystalline material. When the shaping tool 500 is closed, the temperature of the shaping tool 500 is then greater than or equal to the glass transition temperature, if it is an amorphous material, or the melting temperature, if it is a semi-crystalline material. The 500 forming tooling can be held in the closed position and maintained at a temperature greater than or equal to the glass transition temperature, if it is an amorphous material, or the melting temperature, if it is a semi-crystalline material, for a specified period of time.Thus, the first and second parts 510 and 520 of the forming tool 500 have a temperature below the glass transition or melting temperature of the thermoplastic material when the blank 12 is positioned in said tool 500, then the temperature of the first and second parts 510 and 520 of the forming tool 500 is increased until at least the glass transition or melting temperature is reached, the forming tool 500 being closed for shaping the blank 12 when the glass transition or melting temperature is reached.

[0072] After shaping the acoustic component 120, the shaping tool 500 is opened by separating the first part 510 from the second part 520 as illustrated in figures 5 to 7.

[0073] The second face 120d of the acoustic component 120 remains in contact with the second part 520 of the forming tool 500. The first face 120c of the acoustic component 120 is then at a non-zero distance d6, d7 from the first part 510 of the forming tool 500.

[0074] In order to be able to remove the acoustic component 120 from the shaping tool 500 quickly and without damage, it is necessary to peel the acoustic component 120 from the second part 520 of the shaping tool 500.

[0075] For this purpose, a first fluid 601, 701 is projected onto the first face 120a of the acoustic component 120 and a second fluid 801 is injected onto the second face 120b.

[0076] Preferably, the first fluid 601, 701 is projected directly after the opening of the shaping mold 500.

[0077] The injection of the first fluid 601, 701 begins before the injection of the second fluid 801. The injection of the second fluid 801 can begin when the injection of the first fluid 601, 701 is complete. Conversely, the injection of the second fluid 801 can begin before the injection of the first fluid 601, 701 is complete.

[0078] The first fluid and the second fluid may have the same composition. Conversely, the composition of the first fluid may be different from the composition of the second fluid. Using different fluids may allow for better thermal control of the separation.

[0079] The first fluid can be air. The second fluid can be air or carbon dioxide (CO2).

[0080] We will now describe in relation to figures 5 and 6 how the projection of the first fluid 601, 701 is carried out.

[0081] The first fluid 601, 701 is projected onto the first surface 120c of the acoustic component 120 so as to cause a thermal shock at said first surface 120c. The first fluid 601, 701 is projected onto the first surface 120c of the acoustic component 120 so as to obtain a partial detachment of the acoustic component 120 from the second part 520 of the forming tool 500.

[0082] The temperature of the first fluid 601, 701 is lower than the temperature of the acoustic component 120. The temperature of the first fluid 601, 701 must not be too high so as not to degrade the acoustic component 120. If the acoustic component 120 has been heated during its shaping, and consequently has a high temperature, the first fluid 601, 701 can be at ambient temperature.

[0083] According to a first embodiment illustrated in [Fig. 5], the projection of the first fluid 601 is carried out by means of one or more fluid projection devices 600 arranged between the first part 510 and the second part 520 of the forming tool 500. In particular, the fluid projection device(s) 600 are arranged between the first part 510 of the forming tool 500 and the first face 120c of the acoustic component 120. The fluid projection device(s) 600 project the first fluid 601 towards the first face 120c of the acoustic component 120.

[0084] The pressure at the outlet of the fluid projection device(s) 600 can, for example, be between 2 bars and 7 bars.

[0085] Thus, in the first embodiment, the distance d6 between the first part 510 and the second part 520 of the shaping tooling 500 must be relatively large, to allow the presence of the fluid projection device(s) 600.

[0086] It is preferable that the fluid spraying device(s) 600 spray the first fluid 601 onto the largest possible portion of the first face 120c of the acoustic component 120. Preferably, the entire first surface 120a of the acoustic component 120 is exposed to the first fluid 601. At least part of the fluid spraying device(s) 600 can move during the spraying step of the first fluid 601 so as to spray the first fluid 600 onto the entire first surface 120c of the acoustic component 120.

[0087] The fluid projection device(s) 600 may take the form of a gun comprising a nozzle projecting the first fluid 601. Said gun may be operated manually or by means of a robot or machine.

[0088] The fluid spraying device(s) 600 may also take the form of a support carrying a plurality of nozzles spraying the first fluid 601. The support may completely cover the acoustic component 120 when said support is positioned between the first part 510 and the second part 520 of the mold. This support may be handled manually. However, preferably, such a support is handled by a robot or a machine.

[0089] The fluid spraying device(s) 600 may also take the form of a removable hand, for example, a robotic removable hand. This removable hand includes one or more nozzles configured to spray the first fluid. The removable hand may also further include gripping means configured to grasp the acoustic component. Thus, the removable hand can be used to remove the acoustic component from the forming tooling after the injection of the second fluid.

[0090] A combination of several fluid projection devices of different nature is possible.

[0091] Preferably, the distance between the fluid projection device(s) and the first face 120c of the acoustic component 120 is between 1 cm and 10 cm.

[0092] According to a second embodiment illustrated in [Fig. 6], the projection of the first fluid 701 is carried out by means of one or more fluid projection devices 700 arranged around the forming tool 500. The fluid projection device(s) 700 diffuse the first fluid 701 into the space delimited between the first part 510 and the second part 520 of the forming mold 500. Thus, the first fluid 701 diffused into said space comes into contact with the first face 120c of the acoustic component 120.

[0093] The outlet pressure of the fluid projection device(s) 700 can, for example, be between 2 bar and 7 bar, or for example between 5 bar and 7 bar. The projection velocity of the first fluid can, for example, be between 50 m / s and 70 m / s.

[0094] Thus, in the second embodiment, the distance d7 between the first part 510 and the second part 520 of the forming tool 500 must be relatively small, in order to limit the size of the space in which the first fluid 701 is diffused. This improves the contact between the first face 120c of the acoustic component 120 and the first fluid 701.

[0095] The fluid projection device(s) 700 may take the form of a nozzle projecting the first fluid 701.

[0096] Thus, in the second embodiment, the distance d7 between the first part 510 and the second part 520 of the shaping tooling 500 must be relatively small, in order to limit the volume of the space to be filled with the first fluid 701 and to maximize the percentage of first fluid 701 coming into contact with the first face 102c of the acoustic component 120.

[0097] According to a third non-preferred embodiment, the projection of the first fluid is carried out by injecting the first fluid onto the first face of the acoustic component through channels formed in the first part of the shaping tooling.

[0098] We will now describe in relation to [Fig.7] how the injection of the second fluid 801 is carried out.

[0099] The second fluid 801 is injected onto the second surface 120d of the acoustic component 120 so as to detach the acoustic component 120 from the second part 520 of the shaping mold 500.

[0100] The second part 520 of the forming tool 500 comprises a plurality of channels 523 opening onto the surface of the second part 520 opposite the first part 510 of the forming tool 500. The channels 523 are configured to convey the second fluid 801 to the contact of the acoustic component 120, in particular to the contact of the second face 120d of the acoustic component 120.

[0101] The channels 523 can, for example, open onto the prominences 522 of the female part 520. The channels 523 can, for example, open into the molding cavities 521 of the female part 520. The channels 523 can open both onto the prominences 522 and into the molding cavities 521 of the female part 520.

[0102] If the second part of the forming tool is the male part, the channels may, for example, open onto the teeth of the male part. If the second part of the forming tool is the male part, the channels may, for example, open into the recesses of the male part. The channels may open both onto the teeth and into the recesses of the male part.

[0103] The channels 523 are preferably distributed over the entire surface of the second part 520 of the shaping mold 500.

[0104] The expression "between ... and ..." should be understood as including the bounds.

Claims

Demands

1. A method for manufacturing an acoustic component comprising a plurality of hollow acoustic elements having a shape that gradually narrows between a base and a vertex, said method comprising: - positioning a blank (12) between a first part (510) and a second part (520) complementary to a forming tool (500), - shaping said blank (12) into an acoustic component (120) by bringing the first part (510) and the second part (520) of the forming tool (500) together, - separating the first (510) and second (520) parts of the forming tool (500) so that a first face (120c) of the acoustic component (120) is at a distance from the first part (510) of the forming tool (500) and a second face (120d) of the acoustic component (120) opposite the first face (120c) remains in contact with the second part (520) of the shaping tooling (500),- the removal of the acoustic component (120) from the shaping tool (500), the method being characterized in that it comprises, before the removal of the shaping tool (500): - the projection of a first fluid (601; 701) onto the first face (120c) of the acoustic component (120), the first fluid (601; 701) having a temperature lower than the temperature of the acoustic component (120), - the injection of a second fluid (801) onto the second face (120d) of the acoustic component (120) through channels (523) formed in the second part (520) of the shaping tool (500), the injection of the second fluid (801) beginning during or after the start of the projection of the first fluid (601; 701).

2. A manufacturing method according to claim 1, wherein the projection of the first fluid (601; 701) is completed before the injection of the second fluid (801).

3. A manufacturing method according to claim 1, wherein the projection of the first fluid (601; 701) is carried out at least partly simultaneously with the injection of the second fluid (801).

4. A manufacturing method according to any one of claims 1 to 3, wherein the projection of the first fluid (601) is carried out by means of one or more fluid projection devices (600) disposed between the first part (510) and the second part (520) of the forming tooling (500) and projecting the first fluid (601) towards the second face (120a) of the acoustic component (120).

5. A manufacturing method according to any one of claims 1 to 3, wherein the projection of the first fluid (701) is carried out by means of one or more fluid projection devices (700) arranged around the forming tool (500) and projecting the first fluid (701) into the space delimited between the first part (510) and the second part (520) of the forming tool (500) so as to diffuse the first fluid (701) into said space.

6. A manufacturing method according to any one of claims 1 to 5, wherein the first part of the forming tooling comprises a plurality of molding cavities and the second part of the forming tooling comprises a plurality of teeth.

7. A manufacturing method according to any one of claims 1 to 5, wherein the first part (510) of the forming tooling (500) comprises a plurality of teeth (511) and the second part (520) of the forming tooling (500) comprises a plurality of molding cavities (521).

8. A manufacturing method according to any one of claims 1 to 7, wherein the first fluid (601; 701) and the second fluid (801) are air.

9. A manufacturing method according to any one of claims 1 to 8, wherein the blank (12) is made of thermoplastic material, the shaping tooling (500) having a temperature greater than or equal to the glass transition or melting temperature of the thermoplastic material of the blank (12) when shaping said blank (12) into an acoustic component (120).

10. A method for manufacturing an acoustic attenuation panel (100) comprising: - manufacturing an acoustic component (120) according to any one of claims 1 to 9, - assembling the acoustic component (120) with a multicellular body (130) such that the hollow acoustic elements (121) are arranged in the cells (132) of the multicellular body (130), - the assembly of the acoustic component (120) with an acoustic skin (110) so that the acoustic skin (110) covers the bases (121a) of the hollow acoustic elements (121).

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