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EP-4735227-A1 - DEVICE FOR STAMPING ACOUSTIC STRUCTURES

EP4735227A1EP 4735227 A1EP4735227 A1EP 4735227A1EP-4735227-A1

Abstract

The invention relates to a stamping tool (500) for producing an acoustic component, the tool comprising a first part and a second part, the first part (100) having a moulding surface (130) including a plurality of cavities (150) and a punch housing suitable for accommodating the punch (240) of the second part; the second part (200) having a moulding surface (230) forming a plurality of projections, each projection further comprising, at the end thereof, a punch (240) complementary to the punch housing; the stamping tool being characterised in that the punch has a length (Lp) greater than or equal to the length of the projections (Lc), and in that the spacing (l1) between the punch and the punch housing is smaller than the spacing (l2) between the moulding surface of the first part and the moulding surface of the second part.

Inventors

  • LANFANT, Nicolas, Pierre
  • ALGLAVE, Hugues, Laurent
  • VERSAEVEL, Marc
  • MARDJONO, JACKY, NOVI

Assignees

  • Safran

Dates

Publication Date
20260506
Application Date
20240621

Claims (10)

  1. [Claim 1] Stamping tool (500) for manufacturing an acoustic component (1120) comprising a plurality of hollow complex acoustic elements (400) each having a shape gradually narrowing between a base (401) and a top (402), the hollow complex acoustic elements being connected to each other by one or more adjacent edges, the tool comprising a first part (100) and a second part (200) in relative movement with respect to each other between an open position of the tool in which it is possible to arrange a flat polymer film made of precursor material of the acoustic elements between the first and second parts, and a closed position of the tool, in which a plurality of molding cavities in the shape of the elements to be obtained are formed between the first and second parts, the first part (100) having a molding surface (130) forming a plurality of cavities (150) each having a shape corresponding to the external surface of the hollow complex acoustic elements of the acoustic component to be manufactured, the first part further forming, in the extension of each cavity, a punch housing (140); the second part (200) having a molding surface (230) forming a plurality of protuberances corresponding to the shape of the internal surface of the hollow complex acoustic elements of the acoustic component to be manufactured, each protuberance further comprising and at the end thereof a punch (240), complementary to the punch housing; the stamping tool being characterized in that the punch has a length (L p ) greater than or equal to the length of the protuberances (L c ), and in that the spacing (h) between the punch and the punch housing is smaller than the spacing (l 2 ) between the molding surface of the first part and the molding surface of the second part.
  2. [Claim 2] The stamping tool (500) of claim 1, wherein the shape of the mold cavity (150) comprises a first portion (130a) and a second portion (130b), the first portion having a greater taper than the second portion.
  3. [Claim 3] Stamping tool (500) according to claim 2, in which the second portion (230b) has a narrowing of between 1° and 5°, relative to the direction of extension of the acoustic component.
  4. [Claim 4] Stamping tool (500) according to any one of claims 1 to 3, wherein the first (100) and/or the second part (200) comprise means for heating and/or cooling at least their molding surfaces (130, 230).
  5. [Claim 5] A stamping tool (500) according to any one of claims 1 to 4, wherein, in the closed position, the spacing (l 2 ) between the molding surface of the first part (130) and the molding surface of the second part (230) is between 0.1 mm and 0.6 mm.
  6. [Claim 6] A stamping tool (500) according to any one of claims 1 to 5, wherein, in the closed position, the spacing (I) between the punch (240) and the punch housing (140) is less than or equal to 50 pm.
  7. [Claim 7] A stamping tool (500) according to any one of claims 1 to 6, wherein the punch (240) and/or the punch housing (140) comprise at least one air communication capable of being fluidically communicated with the exterior of the stamping tool.
  8. [Claim 8] A stamping tool (500) according to any one of claims 1 to 7, wherein the first portion (100) of the tool is formed of two pieces (1100, 1200), the first piece (1100) comprising the external surfaces defining the molding cavity (130a, 130b) and the second piece (1200) comprising the external surfaces defining the housing of the punch (140).
  9. [Claim 9] Stamping tool according to claim 8, in which communication channels are provided at the junction of the first part (1100) and the second part (1200) of the first part of the tool (100).
  10. [Claim 10] A method of stamping an acoustic component (1120) comprising a plurality of hollow complex acoustic elements (400) each having a shape gradually tapering between a base (401) and a top (402), the hollow complex acoustic elements being connected to each other by one or more adjacent edges, the method comprising: - positioning a preform made of thermoplastic material (610) between the first (200) and the second (100) part of a stamping tool (500) according to any one of claims 1 to 9, the tool being in the open position; - shaping the preform in thermoplastic material by closing the tool. [Claim 11] A method of manufacturing an acoustic attenuation structure (1000) comprising the following steps: - producing an acoustic component (1120) according to the method of claim 10; - the production of a hollow complex acoustic multi-element panel comprising the acoustic component and a plurality of partitions forming acoustic cavities, each complex acoustic element of the acoustic component being housed in an acoustic cavity so as to form an acoustic cell, - the assembly of one face of the complex acoustic multi-element panel with an assembly face of an acoustic skin (1110).

Description

Description Title of the invention: Device for stamping acoustic structures Technical Domain [0001] The present invention relates to the general field of acoustic attenuation structures or panels. It relates more particularly to acoustic attenuation structures used to reduce noise produced in aircraft engines as well as in gas turbines or exhaust thereof. Previous technique [0002] Acoustic attenuation structures typically consist of an acoustic surface plate or skin permeable to the acoustic waves that are to be attenuated and a reflective solid plate or skin called a "closing plate", a cellular body, such as a honeycomb or a porous structure, being arranged between these two walls. In a well-known manner, such panels form Helmholtz-type resonators that make it possible to attenuate acoustic waves in a certain frequency range. Acoustic attenuation structures of this type are described in particular in documents US 5,912,442 and GB 2,314,526. [0003] These acoustic attenuation structures are limited to simple cell shapes such as those of the cells of a conventional NIDA® type structure. With this technology, the frequency processed is of the order of a quarter of the inverse of the cavity height. To process low frequencies, very high cavities are therefore required which, in the case of propulsion systems, considerably increase their drag. In addition, the acoustic performances obtained are limited to the absorption of a specific, but restricted, frequency. [0004] One solution to add other frequencies to the acoustic attenuation is to superimpose two cell bodies having different cell shapes and dimensions. This solution has the disadvantage of significantly increasing the bulk and drag of the acoustic attenuation structure. [0005] A known solution for lowering the attenuated frequency without increasing the size of the attenuation structure consists in placing open cone truncates in cells as described in documents EP 0 738 865 and FR 3 082 987. If this solution makes it possible to reduce the size of the acoustic attenuation structure, the The mass of the structure remains significant, however, and is therefore a disadvantage for use in aircraft where control of the overall mass is always sought. [0006] The increasing use of such acoustic attenuation structures makes any potential improvement in their manufacturing processes commercially interesting. Disclosure of the invention [0007] The invention aims precisely to propose an improvement in the manufacturing processes for acoustic attenuation structures. [0008] For this, it concerns, according to a first of its aspects, a stamping tool for manufacturing an acoustic component comprising a plurality of hollow complex acoustic elements each having a shape that gradually narrows between a base and a top, the hollow complex acoustic elements being connected to each other by one or more adjacent edges, the tool comprising a first part and a second part in relative movement with respect to each other between an open position of the tool in which it is possible to arrange a flat polymer film made of precursor material of the acoustic elements between the first and second parts, and a closed position of the tool in which a plurality of molding cavities in the shape of the elements to be obtained are formed between the first and second parts, the first part having a molding surface forming a plurality of cavities each having a shape corresponding to the external surface of the hollow complex acoustic elements of the acoustic component to be manufactured, the first part further forming, in the extension of each cavity, a punch housing; the second part having a molding surface forming a plurality of protuberances corresponding to the shape of the inner surface of the hollow complex acoustic elements of the acoustic component to be manufactured, each protuberance further comprising and at the end thereof a punch, complementary to the punch housing; the stamping tool being characterized in that the punch has a length greater than or equal to the length of the protuberances, and in that the spacing between the punch and the punch housing is smaller than the spacing between the molding surface of the first part and the molding surface of the second part. [0009] It is understood that the spacing between two surfaces is measured as the smallest distance between said surfaces. For example, between two surfaces parallel to each other, the spacing will be the distance measured between the two surfaces in the direction perpendicular to said surfaces. [0010] The length of the punch is understood here as its extension in the main direction of extension of the tool, for example in the vertical direction. [0011] In one embodiment, the main direction of extension of the tooling can be determined as the direction normal to the plane in which the polymeric film made of precursor material of the complex hollow acoustic elements is arranged. [0012] When a polymeric film is placed betwee