WO2026009154A1 - Method and system for manufacturing a structural element in composite material - Google Patents

Method and system for manufacturing a structural element in composite material

Info

Publication number
WO2026009154A1
WO2026009154A1 PCT/IB2025/056685 IB2025056685W WO2026009154A1 WO 2026009154 A1 WO2026009154 A1 WO 2026009154A1 IB 2025056685 W IB2025056685 W IB 2025056685W WO 2026009154 A1 WO2026009154 A1 WO 2026009154A1
Authority
WO
WIPO (PCT)
Prior art keywords
composite material
layers
tool
cured composite
concave portion
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/IB2025/056685
Other languages
French (fr)
Inventor
Luca ANGELINO
Giovanni BARLETTA
Stefano Corvaglia
Nicola Gallo
Angelo SPORTELLI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leonardo SpA
Original Assignee
Leonardo SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leonardo SpA filed Critical Leonardo SpA
Publication of WO2026009154A1 publication Critical patent/WO2026009154A1/en
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D99/00—Subject matter not provided for in other groups of this subclass
    • B29D99/0003—Producing profiled members, e.g. beams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/12—Moulds or cores; Details thereof or accessories therefor with incorporated means for positioning inserts, e.g. labels
    • B29C33/14—Moulds or cores; Details thereof or accessories therefor with incorporated means for positioning inserts, e.g. labels against the mould wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
    • B64F5/00—Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
    • B64F5/10—Manufacturing or assembling aircraft, e.g. jigs therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C33/00—Moulds or cores; Details thereof or accessories therefor
    • B29C33/30—Mounting, exchanging or centering
    • B29C33/306—Exchangeable mould parts, e.g. cassette moulds, mould inserts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/40—Shaping or impregnating by compression not applied
    • B29C70/42—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles
    • B29C70/44—Shaping or impregnating by compression not applied for producing articles of definite length, i.e. discrete articles using isostatic pressure, e.g. pressure difference-moulding, vacuum bag-moulding, autoclave-moulding or expanding rubber-moulding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
    • B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
    • B29C70/28—Shaping operations therefor
    • B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
    • B29C70/541—Positioning reinforcements in a mould, e.g. using clamping means for the reinforcement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/30—Vehicles, e.g. ships or aircraft, or body parts thereof
    • B29L2031/3076—Aircrafts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
    • B64C2001/0054—Fuselage structures substantially made from particular materials
    • B64C2001/0072—Fuselage structures substantially made from particular materials from composite materials

Definitions

  • the present invention relates to a method for manufacturing a structural element , in particular to a method for manufacturing a structural element in composite material .
  • the present invention also relates to a forming system for manufacturing a structural element , in particular to a forming system of a structural element in composite material .
  • Structural components used in the aviation field are known, for example fuselages and parts thereof , manufactured in composite material .
  • the use of such material has been dictated by the need to reduce the overall weight of the aircrafts and to eliminate or minimi ze the problems of corrosion of the aeronautical structures .
  • the fuselage must guarantee adequate protection of the payload ( crew, passengers , goods , etc . ) , but at the same time it must not exceed the set weight limits .
  • the composite material used consists of fibre material , for example non-cured carbon fibre , which is generally pre-impregnated with fluid resin according to a well-known process . Therefore, the composite material is a material composed of two steps: the matrix and the fibre.
  • each layer of material normally consists of a matrix (in thermosetting resin, thermoplastic, etc.) reinforced by fibres of different nature such as carbon fibres, aramid fibres, glass fibres, etc .
  • the above-mentioned structural elements in composite material are made by laminating together a plurality of layers of said pre-impregnated composite material .
  • each of said layers is laminated on a forming tool.
  • the assembly of laminated layers thus formed is subsequently subjected to a known curing process by applying high pressure and temperature, so as to cure (i.e. cause the polymerization of) the composite material, thus compacting the aforesaid layers together.
  • the structural elements made according to the process described above often have particular shapes, for example comprising particularly angled or inclined portions.
  • the forming tool must necessarily comprise corresponding angled or inclined sections or portions.
  • the Applicant has therefore observed how the lamination of the layers of composite material on such angled or inclined portions is , in some cases , particularly complicated, problematic and prone to inaccuracies .
  • the obj ect of the present invention is to meet the needs set forth above in an optimi zed and cost-ef fective manner .
  • the obj ect of the present invention is to provide a method for manufacturing a structural element in composite material , which has high reliability and limited cost , and allows overcoming the drawback speci fied above and connected to the methods for manufacturing structural elements of known type .
  • this obj ect is achieved by a method for manufacturing a structural element in composite material extending along a longitudinal direction and having at least one concave surface along said direction as claimed in claim 1 .
  • a further obj ect of the present invention is to make a system for manufacturing a structural element in composite material , which has high reliability and limited cost , and allows overcoming the drawback speci fied above and connected to the devices for manufacturing structural elements of known type .
  • this obj ect is achieved by a forming system for manufacturing a structural element in composite material extending along a longitudinal direction and having at least one concave surface along said direction as claimed in claim 11 .
  • Figures 1 to 5 schematically illustrate a side view of following steps of the method for manufacturing according to the present invention.
  • Figure 6 shows a schematic perspective view of a structural element obtained by means of the method according to the present invention and of a forming tool used in the method according to the present invention .
  • the present invention concerns a method for manufacturing a structural element 1 in composite material extending along a longitudinal direction D and having at least one concave surface 2 along the direction D .
  • the longitudinal direction D refers to an ideal line that follows the main development of an obj ect , representing the trend thereof along its extension; therefore , the longitudinal direction D can be , in a non-limiting or constraining manner, rectilinear or curvilinear .
  • the method for manufacturing according to the present invention comprises the initial step of placing a forming tool 3 having a longitudinal forming surface 4 provided with a concave portion 5 .
  • an intermediate tool 6 is arranged on the forming tool 3 in such a way that the intermediate tool 6 engages the concave portion 5 .
  • the intermediate tool 6 comprises a first surface 8 and a second surface 9 opposite to the first surface 8 .
  • the first surface 8 of the intermediate tool 6 is arranged against the concave portion 5 .
  • the intermediate tool 6 has a substantially convex portion complementary to the concave portion 5 , wherein such a substantially convex portion has a radius of curvature for example in a range between 10 and 25 mm, for example 20 mm .
  • the intermediate tool 6 when the intermediate tool 6 engages the concave portion 5 , the intermediate tool 6 completely fills the concave portion in such a way that the concavity of the forming tool 3 is substantially flattened; in greater detail , once the intermediate tool 6 is arranged against the concave portion 5 , the concavity substantially disappears .
  • the concavity when the intermediate tool 6 engages the concave portion 5 , the concavity is substantially indistinguishable with respect to the remaining part of the forming surface 4 of the forming tool 3 ; in even greater detail , the curvature initially defined by the concavity " softens" by ef fect of the insertion of the intermediate tool 6 .
  • the intermediate tool 6 comprises a filler material made by a three-dimensional moulding technique , even more preferably the intermediate tool 6 is made of polylactic acid ( PLA) .
  • PLA polylactic acid
  • the layers of non-cured composite material 7 are laminated onto the intermediate tool 6 and onto the forming tool 3 , in such a way that the layers of non-cured composite material 7 are arranged at least partially on the forming tool 3 and partially on the intermediate tool 6 , thereby obtaining an intermediate shape of the structural element 1 ( illustrated in Figure 3 ) .
  • the lamination of the layers of non-cured composite material 7 is performed by arranging the layers of non-cured composite material 7 partially on the forming tool 3 , in particular on the forming surface 4 , and on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6 .
  • the lamination of the layers of non-cured composite material 7 is performed by means of an automated movement , for example by means of a programmable robot so as to be controlled in an automated manner .
  • the robot is programmed to take a layer of non-cured composite material 7 from a feeding system, for example a conveyor belt , and arrange such layer partially on the forming tool 3 and partially on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6 .
  • a feeding system for example a conveyor belt
  • the robot is configured to arrange , in an automated manner, each layer of non-cured composite material 7 having a predetermined orientation .
  • the robot arranges , in use , on the forming tool 3 , in particular on the forming surface 4 :
  • the feeding system for example a conveyor belt
  • the robot is configured to handle such layers of composite material 7 , in particular to take the layers of non-cured composite material 7 from the feeding system and arrange them partially on the forming tool 3 and partially on the intermediate tool 6 , thereby obtaining said intermediate shape of the structural element 1 .
  • the arrangement of the layers of non-cured composite material 7 could be performed manually by an operator and not by the robot .
  • the intermediate tool 6 is removed from the concave portion 5 of the forming tool 3 and the layers of non-cured composite material 7 are heated to a predetermined temperature , for example by means of infrared heating techniques , resistance heating or heating with a convection oven .
  • the layers of non-cured composite material 7 are adhered against the concave portion 5 , so as to obtain a final shape of the structural element 1 ( illustrated in Figure 6 ) .
  • the layers of non-cured composite material 7 after being heated, preferably uni formly, are adhered by means of the application of an external pressure .
  • such external pressure is exerted by a compaction tool (not illustrated) .
  • the compaction tool comprises an upper compaction portion adapted to apply such external pressure on the assembly defined by the forming tool 3 and by the layers of composite material 7 , in particular on such layers 7 .
  • the upper compaction portion has a smooth surface and can assume di f ferent shapes , for example square , round, spherical , etc .
  • such surface has a dimension such to exert the external pressure on at least one portion of a layer of non-cured composite material 7 .
  • the compaction tool preferably comprises an actuation mechanism, which may be programmable and automated or manual .
  • the actuation mechanism comprises a lever adapted to , following a movement imparted by the operator, actuate the movement of the upper compaction portion .
  • the actuation mechanism is programmable and the upper compaction portion moves on the basis of the programming set on the compaction tool , for example by an operator .
  • the compaction tool comprises a lower hal f-mould si zed complementarily to a lower surface of the forming tool 3 , and an upper hal f-mould si zed complementarily to the forming surface 4 and to the concave portion 5 .
  • heating the layers of non-cured composite material 7 prior to adhering them to the forming surface 4 allows making the layers of non-cured composite material 7 more malleable and faci litating the reduction of potential risks such as cracks or deformations during the compaction .
  • preheating the layers of non-cured composite material 7 allows making the adherence thereof on the forming surface 4 easy .
  • the compaction tool comprises a vacuum bag .
  • the layers of non-cured composite material 7 are heated to a predetermined temperature and the assembly defined by the forming tool 3 and the heated layers of composite material 7 is arranged inside a vacuum bag ( or a membrane ) 10 . Thereafter, the vacuum is applied inside the vacuum bag 10 in such a way that the layers of non-cured composite material 7 adhere to the concave portion 5 of the forming tool 3 , thereby obtaining the final shape of the structural element 1 .
  • the vacuum bag 10 exerts a pressure on the layers of non-cured composite material 7 .
  • the method for manufacturing according to the present invention further comprises the step of applying predetermined temperature and pressure to the structural element 1 formed in the final shape so as to cure the composite material .
  • the present invention also relates to a forming system for manufacturing a structural element 1 in composite material extending along a longitudinal direction D and having at least one concave surface 2 along said direction D .
  • the system according to the present invention comprises the forming tool 3 having the longitudinal forming surface 4 provided with a concave portion 5 , the intermediate tool 6 having the first surface 8 and the second surface 9 opposite to the f irst surface 8 and configured to be arranged on the forming tool 3 in such a way that the first surface 8 is arranged against the concave portion 5 and so as to engage the concave portion 5 .
  • the intermediate tool 6 when the intermediate tool 6 engages the concave portion 5 , the intermediate tool 6 completely fills the concave portion in such a way that the concavity of the forming tool 3 is substantially flattened; in greater detail , once the intermediate tool 6 is arranged against the concave portion 5 , the concavity substantially disappears .
  • the concavity when the intermediate tool 6 engages the concave portion 5 , the concavity is substantially indistinguishable with respect to the remaining part of the forming surface 4 of the forming tool 3 ; in even greater detail , the curvature initially defined by the concavity " softens" by ef fect of the insertion of the intermediate tool 6 .
  • the forming system comprises a lamination device configured to laminate layers of non-cured composite material 7 onto the assembly formed by the forming tool 3 and the intermediate tool 6 so that the layers of non-cured composite material 7 are arranged at least partially on the second surface 9 of the intermediate tool 6 , thereby obtaining an intermediate shape of the structural element 1 .
  • the lamination device comprises a robot programmable so as to be controlled in an automated manner .
  • the robot is programmed to take a layer of noncured composite material 7 from a feeding system, for example from a conveyor belt , and arrange such layer partially on the forming tool 3 , in particular on the forming surface 4 , and partially on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6.
  • the robot is configured to arrange , in an automated manner, each layer of non-cured composite material 7 having a predetermined orientation .
  • the robot arranges , in use , on the forming tool 3 , in particular on the forming surface 4 :
  • the forming system comprises a removal device configured to remove the intermediate tool 6 from the concave portion 5 of the forming tool 3 .
  • the removal device comprises an extractor robot equipped with a robotic arm provided with a gripping system comprising, for example , a gripper structure for grasping and extracting the intermediate tool 6.
  • the extractor robot comprises a control unit configured to control the gripping system on the basis of a command received for example from an external operator .
  • the robot is programmed to laminate the layers of non-cured composite material 7 onto the assembly formed by the forming tool 3 and the intermediate tool 6 so that the layers of non-cured composite material 7 are arranged partially on the forming tool 3 , in particular on the forming surface 4 , and partially on the intermediate tool 6 , in particular on the second surface 9 .
  • the forming system further comprises an adhering device configured to adhere the layers of non-cured composite material 7 against the concave portion 5 , so as to obtain a final shape of the structural element 1 .
  • the adhering device comprises a heating tool for heating the layers of non-cured composite material to a predetermined temperature and a compaction tool adapted to apply a pressure on such heated layers of non-cured composite material 7 .
  • the heating tool comprises an infrared source or a convection oven .
  • the compaction tool is a vacuum bag in which the assembly defined by the forming tool 3 and the preheated layers of non-cured composite material 7 is arranged .
  • the vacuum is applied inside the vacuum bag 10 in such a way that the layers of non-cured composite material 7 adhere to the concave portion 5 of the forming tool 3 , thereby obtaining said final shape of the structural element 1 .
  • the compaction tool (not illustrated) comprises an upper compaction portion adapted to apply such external pressure on the assembly defined by the forming tool 3 and by the layers of composite material 7 , in particular on such layers 7 .
  • the upper compaction portion has a smooth surface and can assume di f ferent shapes , for example square , round, spherical , etc .
  • such surface has a dimension such to exert the external pressure on at least one portion of a layer of non-cured composite material 7 .
  • the compaction tool comprises an actuation mechanism, which may be programmable and automated or manual .
  • the actuation mechanism comprises a lever adapted to , following a movement imparted by the operator, actuate the movement of the upper compaction portion .
  • the compaction tool comprises a lower hal f-mould si zed complementarily to a lower surface of the forming tool 3 , and an upper hal f-mould si zed complementarily to the forming surface 4 and to the concave portion 5 .
  • the intermediate tool 6 is made by three- dimensional moulding, thus it is possible to make intermediate tools 6 having di f ferent shapes or consisting of di f ferent material , in such a way that they adapt to the speci fic angled or inclined portion to be laminated .

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

The present invention concerns a method for manufacturing a structural element (1) in composite material extending along a longitudinal direction (D) and having at least one concave surface (2) along said direction (D). The method comprises the steps of placing a forming tool (3); arranging an intermediate tool (6) on the forming tool (3) in such a way that the intermediate tool (6) engages the concave portion (5); laminating layers of non-cured composite material (7) on the assembly thereby obtained, thereby obtaining an intermediate shape of the structural element ( 1 ); removing the intermediate tool (6) from the concave portion (5) of the forming tool (3); and adhering said layers of non-cured composite material (7) against the concave portion (5), so as to obtain a final shape of the structural element (1). The step of adhering said layers of composite material comprises the further steps of : applying a predetermined temperature to the layers of non-cured composite material (7) and pressing the layers of non-cured composite material (7) against the concave portion (5).

Description

"METHOD AND SYSTEM FOR MANUFACTURING A STRUCTURAL ELEMENT IN
COMPOSITE MATERIAL"
Cross-Reference to Related Applications
This Patent Application claims priority from Italian Patent Application No . 102024000015241 filed on July 2 , 2024 , the entire disclosure of which is incorporated herein by reference .
Technical Field
The present invention relates to a method for manufacturing a structural element , in particular to a method for manufacturing a structural element in composite material .
The present invention also relates to a forming system for manufacturing a structural element , in particular to a forming system of a structural element in composite material .
State of the Prior Art
Structural components used in the aviation field are known, for example fuselages and parts thereof , manufactured in composite material . The use of such material has been dictated by the need to reduce the overall weight of the aircrafts and to eliminate or minimi ze the problems of corrosion of the aeronautical structures .
In the state of the art , there are aeronautical structural elements which are produced in light alloy and, therefore , in metal material , for example the frames of the windows , or small windows , which then have to be applied to the fuselage .
The use of such metal elements and the mounting thereof in contact with the structures in composite material cause problems of galvanic coupling with related risks of corrosion of the metal and need to increase the inspection levels . This involves an increase in the total costs for the producers of such components and, therefore , for the airline companies .
Furthermore , as is known, the fuselage must guarantee adequate protection of the payload ( crew, passengers , goods , etc . ) , but at the same time it must not exceed the set weight limits .
In addition, the use of metal components , while of fering greater strength, involves an increase in total costs .
Therefore , the need arises to make such structural elements in composite material , in order to reduce the overall weight of the aircrafts and to reduce or eliminate the risks of galvanic coupling mentioned above .
In the most common solutions , the composite material used consists of fibre material , for example non-cured carbon fibre , which is generally pre-impregnated with fluid resin according to a well-known process . Therefore, the composite material is a material composed of two steps: the matrix and the fibre. In particular, in the case of pre-impregnated materials, each layer of material normally consists of a matrix (in thermosetting resin, thermoplastic, etc.) reinforced by fibres of different nature such as carbon fibres, aramid fibres, glass fibres, etc .
Typically, the above-mentioned structural elements in composite material are made by laminating together a plurality of layers of said pre-impregnated composite material .
In greater detail, each of said layers is laminated on a forming tool.
The assembly of laminated layers thus formed is subsequently subjected to a known curing process by applying high pressure and temperature, so as to cure (i.e. cause the polymerization of) the composite material, thus compacting the aforesaid layers together.
Lamination processes of this type are known in documents US 2024/0076060 Al and US 2022/0024159 Al.
The structural elements made according to the process described above often have particular shapes, for example comprising particularly angled or inclined portions.
Consequently, the forming tool must necessarily comprise corresponding angled or inclined sections or portions. The Applicant has therefore observed how the lamination of the layers of composite material on such angled or inclined portions is , in some cases , particularly complicated, problematic and prone to inaccuracies .
The need is therefore felt in the sector to improve the manufacturing process of structural components having particular shapes , for example particularly angled or inclined portions .
The obj ect of the present invention is to meet the needs set forth above in an optimi zed and cost-ef fective manner .
Summary of the Invention
The obj ect of the present invention is to provide a method for manufacturing a structural element in composite material , which has high reliability and limited cost , and allows overcoming the drawback speci fied above and connected to the methods for manufacturing structural elements of known type .
According to the invention, this obj ect is achieved by a method for manufacturing a structural element in composite material extending along a longitudinal direction and having at least one concave surface along said direction as claimed in claim 1 .
A further obj ect of the present invention is to make a system for manufacturing a structural element in composite material , which has high reliability and limited cost , and allows overcoming the drawback speci fied above and connected to the devices for manufacturing structural elements of known type .
According to the invention, this obj ect is achieved by a forming system for manufacturing a structural element in composite material extending along a longitudinal direction and having at least one concave surface along said direction as claimed in claim 11 .
Brief Description of the Drawings
For a better understanding of the present invention, a preferred embodiment is described in the following, by way of non-limiting example and with reference to the accompanying drawings , wherein :
• Figures 1 to 5 schematically illustrate a side view of following steps of the method for manufacturing according to the present invention; and
• Figure 6 shows a schematic perspective view of a structural element obtained by means of the method according to the present invention and of a forming tool used in the method according to the present invention .
Detailed Description of the Invention
The present invention concerns a method for manufacturing a structural element 1 in composite material extending along a longitudinal direction D and having at least one concave surface 2 along the direction D . It is understood that in the present description, the longitudinal direction D refers to an ideal line that follows the main development of an obj ect , representing the trend thereof along its extension; therefore , the longitudinal direction D can be , in a non-limiting or constraining manner, rectilinear or curvilinear .
As is illustrated in Figure 1 , the method for manufacturing according to the present invention comprises the initial step of placing a forming tool 3 having a longitudinal forming surface 4 provided with a concave portion 5 .
Subsequently, as is illustrated in Figure 2 , an intermediate tool 6 is arranged on the forming tool 3 in such a way that the intermediate tool 6 engages the concave portion 5 .
In particular, the intermediate tool 6 comprises a first surface 8 and a second surface 9 opposite to the first surface 8 .
In particular, the first surface 8 of the intermediate tool 6 is arranged against the concave portion 5 .
In detail , the intermediate tool 6 has a substantially convex portion complementary to the concave portion 5 , wherein such a substantially convex portion has a radius of curvature for example in a range between 10 and 25 mm, for example 20 mm . Preferably, when the intermediate tool 6 engages the concave portion 5 , the intermediate tool 6 completely fills the concave portion in such a way that the concavity of the forming tool 3 is substantially flattened; in greater detail , once the intermediate tool 6 is arranged against the concave portion 5 , the concavity substantially disappears .
In other words , when the intermediate tool 6 engages the concave portion 5 , the concavity is substantially indistinguishable with respect to the remaining part of the forming surface 4 of the forming tool 3 ; in even greater detail , the curvature initially defined by the concavity " softens" by ef fect of the insertion of the intermediate tool 6 .
Preferably, the intermediate tool 6 comprises a filler material made by a three-dimensional moulding technique , even more preferably the intermediate tool 6 is made of polylactic acid ( PLA) .
Thereafter, as is illustrated in Figure 3 , the layers of non-cured composite material 7 are laminated onto the intermediate tool 6 and onto the forming tool 3 , in such a way that the layers of non-cured composite material 7 are arranged at least partially on the forming tool 3 and partially on the intermediate tool 6 , thereby obtaining an intermediate shape of the structural element 1 ( illustrated in Figure 3 ) . In particular, the lamination of the layers of non-cured composite material 7 is performed by arranging the layers of non-cured composite material 7 partially on the forming tool 3 , in particular on the forming surface 4 , and on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6 .
Conveniently, the lamination of the layers of non-cured composite material 7 is performed by means of an automated movement , for example by means of a programmable robot so as to be controlled in an automated manner .
In particular, the robot is programmed to take a layer of non-cured composite material 7 from a feeding system, for example a conveyor belt , and arrange such layer partially on the forming tool 3 and partially on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6 .
In particular, the robot is configured to arrange , in an automated manner, each layer of non-cured composite material 7 having a predetermined orientation . By way of example , the robot arranges , in use , on the forming tool 3 , in particular on the forming surface 4 :
- a first plurality of layers of non-cured composite material 7 according to a 0 ° orientation along the longitudinal direction D, namely an orientation parallel to the longitudinal direction D; - a second plurality of layers of non-cured composite material 7 according to a 45 ° orientation with respect to the longitudinal direction D;
- a third plurality of layers of non-cured composite material 7 according to a -45 ° orientation with respect to the longitudinal direction D, namely according to an orientation perpendicular to that of the second plurality of layers ; and
- a fourth plurality of layers of non-cured composite material 7 according to a 90 ° orientation with respect to the longitudinal direction D .
In particular, the feeding system, for example a conveyor belt , is configured to feed layers of non-cured composite material 7 to the robot , which is configured to handle such layers of composite material 7 , in particular to take the layers of non-cured composite material 7 from the feeding system and arrange them partially on the forming tool 3 and partially on the intermediate tool 6 , thereby obtaining said intermediate shape of the structural element 1 .
In an alternative embodiment , the arrangement of the layers of non-cured composite material 7 could be performed manually by an operator and not by the robot .
At this point , as is illustrated in Figure 4 , the intermediate tool 6 is removed from the concave portion 5 of the forming tool 3 and the layers of non-cured composite material 7 are heated to a predetermined temperature , for example by means of infrared heating techniques , resistance heating or heating with a convection oven .
Thereafter, the layers of non-cured composite material 7 are adhered against the concave portion 5 , so as to obtain a final shape of the structural element 1 ( illustrated in Figure 6 ) .
In particular, the layers of non-cured composite material 7 , after being heated, preferably uni formly, are adhered by means of the application of an external pressure .
Preferably, such external pressure is exerted by a compaction tool (not illustrated) .
Preferably, the compaction tool comprises an upper compaction portion adapted to apply such external pressure on the assembly defined by the forming tool 3 and by the layers of composite material 7 , in particular on such layers 7 .
By way of example , the upper compaction portion has a smooth surface and can assume di f ferent shapes , for example square , round, spherical , etc . In particular, such surface has a dimension such to exert the external pressure on at least one portion of a layer of non-cured composite material 7 . The compaction tool preferably comprises an actuation mechanism, which may be programmable and automated or manual . For example , the actuation mechanism comprises a lever adapted to , following a movement imparted by the operator, actuate the movement of the upper compaction portion .
Alternatively, the actuation mechanism is programmable and the upper compaction portion moves on the basis of the programming set on the compaction tool , for example by an operator .
According to a possible embodiment , the compaction tool comprises a lower hal f-mould si zed complementarily to a lower surface of the forming tool 3 , and an upper hal f-mould si zed complementarily to the forming surface 4 and to the concave portion 5 .
Advantageously, heating the layers of non-cured composite material 7 prior to adhering them to the forming surface 4 , allows making the layers of non-cured composite material 7 more malleable and faci litating the reduction of potential risks such as cracks or deformations during the compaction .
Furthermore , preheating the layers of non-cured composite material 7 allows making the adherence thereof on the forming surface 4 easy .
According to a possible embodiment , the compaction tool comprises a vacuum bag . In particular, to adhere the layers of non-cured composite material 7 against the concave portion 5 of the forming tool 3 , the layers of non-cured composite material 7 are heated to a predetermined temperature and the assembly defined by the forming tool 3 and the heated layers of composite material 7 is arranged inside a vacuum bag ( or a membrane ) 10 . Thereafter, the vacuum is applied inside the vacuum bag 10 in such a way that the layers of non-cured composite material 7 adhere to the concave portion 5 of the forming tool 3 , thereby obtaining the final shape of the structural element 1 .
In particular, by applying the vacuum inside the vacuum bag 10 ( or membrane ) , the vacuum bag 10 exerts a pressure on the layers of non-cured composite material 7 .
Preferably, the method for manufacturing according to the present invention further comprises the step of applying predetermined temperature and pressure to the structural element 1 formed in the final shape so as to cure the composite material .
The present invention also relates to a forming system for manufacturing a structural element 1 in composite material extending along a longitudinal direction D and having at least one concave surface 2 along said direction D .
The system according to the present invention comprises the forming tool 3 having the longitudinal forming surface 4 provided with a concave portion 5 , the intermediate tool 6 having the first surface 8 and the second surface 9 opposite to the f irst surface 8 and configured to be arranged on the forming tool 3 in such a way that the first surface 8 is arranged against the concave portion 5 and so as to engage the concave portion 5 .
Preferably, when the intermediate tool 6 engages the concave portion 5 , the intermediate tool 6 completely fills the concave portion in such a way that the concavity of the forming tool 3 is substantially flattened; in greater detail , once the intermediate tool 6 is arranged against the concave portion 5 , the concavity substantially disappears .
In other words , when the intermediate tool 6 engages the concave portion 5 , the concavity is substantially indistinguishable with respect to the remaining part of the forming surface 4 of the forming tool 3 ; in even greater detail , the curvature initially defined by the concavity " softens" by ef fect of the insertion of the intermediate tool 6 .
The forming system comprises a lamination device configured to laminate layers of non-cured composite material 7 onto the assembly formed by the forming tool 3 and the intermediate tool 6 so that the layers of non-cured composite material 7 are arranged at least partially on the second surface 9 of the intermediate tool 6 , thereby obtaining an intermediate shape of the structural element 1 .
In particular, the lamination device comprises a robot programmable so as to be controlled in an automated manner . In detail , the robot is programmed to take a layer of noncured composite material 7 from a feeding system, for example from a conveyor belt , and arrange such layer partially on the forming tool 3 , in particular on the forming surface 4 , and partially on the intermediate tool 6 , in particular on the second surface 9 of the intermediate tool 6.
In particular, the robot is configured to arrange , in an automated manner, each layer of non-cured composite material 7 having a predetermined orientation . By way of example , the robot arranges , in use , on the forming tool 3 , in particular on the forming surface 4 :
- a first plurality of layers of non-cured composite material 7 according to a 0 ° orientation along the longitudinal direction D, namely an orientation parallel to the longitudinal direction D;
- a second plurality of layers of non-cured composite material 7 according to a 45 ° orientation with respect to the longitudinal direction D;
- a third plurality of layers of non-cured composite material 7 according to a -45 ° orientation with respect to the longitudinal direction D, namely according to an orientation perpendicular to that of the second plurality of layers ; and - a fourth plurality of layers of non-cured composite material 7 according to a 90 ° orientation with respect to the longitudinal direction D .
The forming system comprises a removal device configured to remove the intermediate tool 6 from the concave portion 5 of the forming tool 3 .
Preferably, the removal device comprises an extractor robot equipped with a robotic arm provided with a gripping system comprising, for example , a gripper structure for grasping and extracting the intermediate tool 6.
In particular, the extractor robot comprises a control unit configured to control the gripping system on the basis of a command received for example from an external operator .
In particular, the robot is programmed to laminate the layers of non-cured composite material 7 onto the assembly formed by the forming tool 3 and the intermediate tool 6 so that the layers of non-cured composite material 7 are arranged partially on the forming tool 3 , in particular on the forming surface 4 , and partially on the intermediate tool 6 , in particular on the second surface 9 .
The forming system further comprises an adhering device configured to adhere the layers of non-cured composite material 7 against the concave portion 5 , so as to obtain a final shape of the structural element 1 . Preferably, the adhering device comprises a heating tool for heating the layers of non-cured composite material to a predetermined temperature and a compaction tool adapted to apply a pressure on such heated layers of non-cured composite material 7 .
Preferably, the heating tool comprises an infrared source or a convection oven .
Preferably, the compaction tool is a vacuum bag in which the assembly defined by the forming tool 3 and the preheated layers of non-cured composite material 7 is arranged .
Thereafter, the vacuum is applied inside the vacuum bag 10 in such a way that the layers of non-cured composite material 7 adhere to the concave portion 5 of the forming tool 3 , thereby obtaining said final shape of the structural element 1 .
The compaction tool can be automated or used manually by an operator .
Alternatively, the compaction tool (not illustrated) comprises an upper compaction portion adapted to apply such external pressure on the assembly defined by the forming tool 3 and by the layers of composite material 7 , in particular on such layers 7 .
By way of example , the upper compaction portion has a smooth surface and can assume di f ferent shapes , for example square , round, spherical , etc . In particular, such surface has a dimension such to exert the external pressure on at least one portion of a layer of non-cured composite material 7 .
The compaction tool comprises an actuation mechanism, which may be programmable and automated or manual . For example , the actuation mechanism comprises a lever adapted to , following a movement imparted by the operator, actuate the movement of the upper compaction portion .
Alternatively, the actuation mechanism is automated and the upper compaction portion moves on the basis of the programming set on the compaction tool .
According to a possible embodiment , the compaction tool comprises a lower hal f-mould si zed complementarily to a lower surface of the forming tool 3 , and an upper hal f-mould si zed complementarily to the forming surface 4 and to the concave portion 5 .
By examining the characteristics of the method and the forming system for manufacturing a structural element 1 made according to the present invention, the advantages that the latter allows obtaining are evident .
Firstly, the use of the intermediate tool 6 allows a lamination of the layers of composite material onto angled or inclined portions of a structural element 1 avoiding inaccuracies and problems . In this regard, the use of the intermediate tool 6 allows the lamination of the layers of composite material on windows or small windows having an angled portion or anyway with a particularly pronounced concavity, for example a small window of an aircraft .
Furthermore , the intermediate tool 6 is made by three- dimensional moulding, thus it is possible to make intermediate tools 6 having di f ferent shapes or consisting of di f ferent material , in such a way that they adapt to the speci fic angled or inclined portion to be laminated .
It is clear that modi fications and variations can be made to the method and to the device described and illustrated herein without thereby departing from the scope of protection defined by the claims .

Claims

1. Method for manufacturing a structural element (1) in composite material extending along a longitudinal direction (D) and having at least one concave surface (2) along said direction (D) ; the method comprising the steps of: a) placing a forming tool (3) having a longitudinal forming surface (4) provided with a concave portion (5) ; b) arranging an intermediate tool (6) on the forming tool (3) in such a way that the intermediate tool (6) engages the concave portion (5) ; c) laminating layers of non-cured composite material (7) onto the assembly thereby obtained so that the layers of non-cured composite material (7) are arranged at least partially on said intermediate tool (6) , thereby obtaining an intermediate shape of the structural element (1) ; d) removing the intermediate tool (6) from the concave portion (5) of the forming tool (3) ; and e) adhering said layers of non-cured composite material (7) against the concave portion (5) , so as to obtain a final shape of the structural element (1) ; wherein the step e) of adhering said layers of non-cured composite material (7) against the concave portion (5) of the forming tool (3) comprises the further steps of: el) applying a predetermined temperature to the layers of non-cured composite material (7) ; and e2) pressing the layers of non-cured composite material (7) against the concave portion (5) .
2. Method according to claim 1, wherein the step c) of laminating layers of non-cured composite material comprises arranging the layers of non-cured composite material (7) partially on said forming tool (3) and partially on said intermediate tool (6) , thereby obtaining said intermediate shape of the structural element (1) .
3. Method according to claim 2, wherein the intermediate tool (6) comprises a first surface (8) and a second surface (9) opposite to the first surface (8) ; wherein the step b) of arranging the intermediate tool (6) on the forming tool (3) is performed by arranging the first surface (8) against the concave portion (5) ; and wherein the step c) of laminating layers of noncured composite material (7) is performed by arranging the layers of non-cured composite material (7) partially on said forming surface (4) of the forming tool (3) and partially on the second surface (9) of the intermediate tool (6) .
4. Method for manufacturing according to any one of the preceding claims, wherein the step c) of laminating layers of non-cured composite material (7) is performed by automated robotic means.
5. Method for manufacturing according to claim 4, wherein the automated robotic means comprise a feeding system configured to feed layers of non-cured composite material (7) to a handling system; wherein the handling system is configured to take said layers of non-cured composite material (7) from the feeding system and partially arrange them on the forming tool (3) and partially on the intermediate tool (6) .
6. Method for manufacturing according to any one of claims 1 to 3, wherein the step c) of laminating layers of non-cured composite material (7) is performed manually.
7. Method for manufacturing according to any one of the preceding claims, wherein the step e2) of pressing the layers of non-cured composite material (7) against the concave portion (5) comprises the further step of arranging a compaction tool adapted to exert a pressure to the layers of non-cured composite material (7) .
8. Method for manufacturing according to claim 7, wherein the compaction tool comprises a vacuum bag (10) and wherein the step e) of adhering said layers of non-cured composite material (7) against the concave portion (5) of the forming tool (3) comprises the further steps of: prior to the step el) , arranging the assembly defined by the forming tool (3) and the layers of non-cured composite material (7) inside the vacuum bag (10) ; and wherein the step e2) comprises applying a vacuum within the vacuum bag (10) such that the latter applies a pressure on the layers of non-cured composite material (7) and such that the layers of non-cured composite material (7) adhere to the concave portion (5) of the forming tool (3) , thereby obtaining said final shape of the structural element (1) .
9. Method for manufacturing according to any one of the preceding claims, further comprising the step of applying a predetermined temperature and pressure to the structural element (1) formed in said final shape so as to cure the composite material.
10. Method for manufacturing according to any one of the preceding claims, wherein the intermediate tool (6) comprises a filler material, wherein the filler material is made by a three-dimensional moulding technique.
11. Forming system for manufacturing a structural element (1) of composite material extending along a longitudinal direction (D) and having at least one concave surface (2) along said direction (D) , the system comprising: a forming tool (3) having a longitudinal forming surface (4) provided with a concave portion (5) ; an intermediate tool (6) having a first surface (8) and a second surface (9) opposite to the first surface (8) and configured to be arranged on the forming tool (3) in such a way that the first surface (8) is arranged against the concave portion (5) engaging the latter; laminating means configured to laminate layers of noncured composite material (7) onto the assembly formed by the forming tool (3) and the intermediate tool (6) such that the layers of non-cured composite material (7) are arranged at least partially on the second surface (9) of the intermediate tool (6) , thereby obtaining an intermediate shape of the structural element (1) ; removing means configured to remove the intermediate tool (6) from the concave portion (5) of the forming tool ( 3 ) ; and adhering means configured to adhere said layers of noncured composite material (7) against the concave portion (5) , so as to obtain a final shape of the structural element (1) •
12. Forming system as claimed in claim 11, wherein the laminating means are configured to laminate the layers of non-cured composite material (7) on the assembly formed by the forming tool (3) and the intermediate tool (6) such that the layers of non-cured composite material (7) are arranged partially on said forming tool (3) and partially on said intermediate tool (6) .
PCT/IB2025/056685 2024-07-02 2025-07-01 Method and system for manufacturing a structural element in composite material Pending WO2026009154A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220024159A1 (en) 2018-12-10 2022-01-27 Mitsubishi Heavy Industries, Ltd. Molding method and molding jig for laminated body
US20240076060A1 (en) 2020-11-23 2024-03-07 Leonardo S.P.A. Method and device for manufacturing a structural element in composite material with a z-shaped profile

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220024159A1 (en) 2018-12-10 2022-01-27 Mitsubishi Heavy Industries, Ltd. Molding method and molding jig for laminated body
US20240076060A1 (en) 2020-11-23 2024-03-07 Leonardo S.P.A. Method and device for manufacturing a structural element in composite material with a z-shaped profile

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