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Title:
METHOD OF MANUFACTURING REINFORCED LIGHTWEIGHT COMPOSITES
Document Type and Number:
WIPO Patent Application WO/2023/002205
Kind Code:
A1
Abstract:
There is disclosed a method of manufacturing edge-reinforced lightweight composite components (10), the method comprising: disposing at least one layer (or mat) of fibres on a first mould surface (31); disposing a filler (13) on said layer or layers (16) of fibres, the filler (13) being adapted to provide localized reinforcement at the edge of the composite component (10); forming a loop (18) around the filler (13) with at least one of the layer or layers (16) of fibres; disposing a second mould surface (32) relative to the first mould surface (31), such that a mould cavity is formed between said first and second mould surfaces; and transferring a mixture (41) through a mould (30) into the mould cavity (33), the mixture (41) comprising a resin and a curing agent, thereby allowing said mixture (41) to impregnate the layer or layers of fibres, before the resin cures. Reinforced lightweight composite components (10) having high stiffness at the edge can thus be advantageously manufactured, using a standard Resin Transfer Moulding technigue, while preventing sharp and/or unsightly edges.

Inventors:
VIRDI BHUPINDER (GB)
SIEGL TOBIAS (GB)
VERGE SPENCER (GB)
Application Number:
PCT/GB2022/051911
Publication Date:
January 26, 2023
Filing Date:
July 21, 2022
Export Citation:
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Assignee:
ASTON MARTIN LAGONDA LTD (GB)
International Classes:
B29C70/48; B29C63/02; B29C70/08; B29C70/30; B29C70/86; B29L31/00
Foreign References:
US20200384710A12020-12-10
US20080236739A12008-10-02
US20130127092A12013-05-23
Other References:
AIREX AG: "www.3ACcorematerials.com Europe ??? Middle East ??? India ??? Africa", 28 February 2017 (2017-02-28), XP055672401, Retrieved from the Internet [retrieved on 20200228]
Attorney, Agent or Firm:
MORBIDINI, Marco (GB)
Download PDF:
Claims:
CLAIMS:

1. A method of manufacturing a reinforced lightweight composite component, the method comprising:

(a) providing a fibre preform on a first mould surface, wherein said fibre preform comprises a first reinforcement portion comprising a filler disposed at an edge region of the fibre preform, and a second, non-reinforced portion that conforms to the first mould surface;

(b) disposing a second mould surface relative to the first mould surface, such that a mould cavity is defined between the first and second mould surfaces, wherein the second mould surface comprises first and second mould surface areas adapted to conform, respectively, to the first and second portions of the fibre preform, wherein the second mould surface area also conforms to the first mould surface; and

(c) transferring a mixture into said mould cavity, said mixture comprising a resin and a curing agent, and allowing said mixture to impregnate said first and second portions of the fibre preform.

2. The method of claim 1 , wherein the fibre preform comprises dry fibres.

3. The method of claims 1 or 2, wherein the fibre preform comprises at least one fibre layer; optionally, wherein any one or more of said at least one fibre layer is a fibre mat; optionally, wherein one or more of said one or more fibre layers has a substantially uniform thickness.

4. The method of claim 1 , 2 or 3, wherein the fibre preform comprises glass and/or carbon fibres.

5 The method of any one of the previous claims, wherein the first mould surface is defined on a face of a first mould half.

6. The method of claim 5, wherein the first mould half is arranged as a lower mould half.

7. The method of any one of the preceding claims, wherein the second mould surface is defined on a face of a second mould half.

8. The method of claim 7, wherein the second mould half is arranged as an upper mould half.

9. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing the fibre preform on the first mould surface; optionally, wherein disposing the fibre preform on the first mould surface comprises disposing at least one fibre layer on the first moult surface; optionally, wherein a fibre lay-up comprising multiple fibre layers is disposed on the first mould surface, wherein each fibre layer may be in the form of a fibre mat.

10. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing the filler on the edge region of the fibre preform.

11. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing fibres at least partially around the filler; optionally, wrapping or folding the fibre preform, or at least one of the one or more fibre layers, around the filler, to form said first portion at at least one position along the edge region of the fibre preform.

12. The method of claim 11, wherein the step of providing the fibre preform on the first mould surface comprises: wrapping or folding the fibre preform, or at least one of the one or more fibre layers, completely around the filler, optionally all along the edge region of the fibre preform.

13. The method of any one of the preceding claims, wherein the filler comprises a foam material.

14. The method of any one of the preceding claims, wherein the filler comprises a generally convexly curved cross section.

15. The method of claim 14, wherein the generally convexly curved cross section is ovoidal, elliptical or circular.

16. The method of claim 14 or 15, wherein the filler is shaped to confer to an edge of the reinforced lightweight composite component a minimum curvature radius, such as 5mm.

17. The method of any one of the preceding claims, wherein the filler is adapted to expand with a temperature increase.

18. The method of any one of the preceding claims, wherein the method further comprises heating the mould cavity; optionally, wherein said heating the mould cavity is according to a predetermined schedule to control the expansion of the filler.

19. The method of any one of the preceding claims, wherein said composite component is a generally two-dimensional or shell-like composite component and said edge region is an external and/or an internal edge region of said composite component.

20. The method of any one of the preceding claims, wherein the method further comprises injecting the mixture through a mould.

21. The method of claim 20, wherein the method further comprises applying a pressure to the mixture and/or applying a vacuum to the mould cavity.

22. The method of any one of the preceding claims, wherein the resin is a thermoset.

23. The method of any one of the preceding claims, wherein the method further comprises cooling the mould and/or demoulding the reinforced lightweight composite component.

24. The method of any one of the preceding claims, wherein the method further comprises: applying a finish layer to the reinforced lightweight composite component, optionally by using an autoclave process.

25. The method of any one of the preceding claims, wherein the reinforced lightweight composite component is a car seat, or a part therefor.

AMENDED CLAIMS received by the International Bureau on CLAIMS December 2022 (16.12.22)

1. A method of manufacturing a reinforced lightweight composite component by resin transfer moulding, the resin transfer moulding comprising:

(a) providing a fibre preform on a first mould surface, wherein said fibre preform comprises a first reinforcement portion comprising a filler disposed at an edge region of the fibre preform, and a second, non-reinforced portion that conforms to the first mould surface;

(b) disposing a second mould surface relative to the first mould surface, such that a mould cavity is defined between the first and second mould surfaces, wherein the second mould surface comprises first and second mould surface areas adapted to conform, respectively, to the first and second portions of the fibre preform, wherein the second mould surface area also conforms to the first mould surface; and

(c) transferring a mixture into said mould cavity, said mixture comprising a resin and a curing agent, and allowing said mixture to impregnate said first and second portions of the fibre preform.

2. The method of claim 1 , wherein the fibre preform comprises dry fibres.

3. The method of claims 1 or 2, wherein the fibre preform comprises at least one fibre layer; optionally, wherein any one or more of said at least one fibre layer is a fibre mat; optionally, wherein one or more of said one or more fibre layers has a substantially uniform thickness

4. The method of claim 1 , 2 or 3, wherein the fibre preform comprises glass and/or carbon fibres.

5. The method of any one of the previous claims, wherein the first mould surface is defined on a face of a first mould half.

6. The method of claim 5, wherein the first mould half is arranged as a lower mould half.

7. The method of any one of the preceding claims, wherein the second mould surface is defined on a face of a second mould half.

8. The method of claim 7, wherein the second mould half is arranged as an upper mould half.

9. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing the fibre preform on the first mould surface; optionally, wherein disposing the fibre preform on the first mould surface comprises disposing at least one fibre layer on the first mould surface; optionally, wherein a fibre lay-up comprising multiple fibre layers is disposed on the first mould surface, wherein each fibre layer may be in the form of a fibre mat.

10. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing the filler on the edge region of the fibre preform.

11. The method of any one of the preceding claims, wherein the step of providing the fibre preform on the first mould surface comprises: disposing fibres at least partially around the filler; optionally, wrapping or folding the fibre preform, or at least one of the one or more fibre layers, around the filler, to form said first portion at at least one position along the edge region of the fibre preform.

12. The method of claim 11, wherein the step of providing the fibre preform on the first mould surface comprises: wrapping or folding the fibre preform, or at least one of the one or more fibre layers, completely around the filler, optionally all along the edge region of the fibre preform.

13. The method of any one of the preceding claims, wherein the filler comprises a foam material.

14. The method of any one of the preceding claims, wherein the filler comprises a generally convexly curved cross section.

15. The method of claim 14, wherein the generally convexly curved cross section is ovoidal, elliptical or circular.

16. The method of claim 14 or 15, wherein the filler is shaped to confer to an edge of the reinforced lightweight composite component a minimum curvature radius, such as 5mm.

17. The method of any one of the preceding claims, wherein the filler is adapted to expand with a temperature increase.

18. The method of any one of the preceding claims, wherein the method further comprises heating the mould cavity; optionally, wherein said heating the mould cavity is according to a predetermined schedule to control the expansion of the filler.

19. The method of any one of the preceding claims, wherein said composite component is a generally two-dimensional or shell-like composite component and said edge region is an external and/or an internal edge region of said composite component.

20. The method of any one of the preceding claims, wherein the method further comprises injecting the mixture through a mould.

21. The method of claim 20, wherein the method further comprises applying a pressure to the mixture and/or applying a vacuum to the mould cavity.

22. The method of any one of the preceding claims, wherein the resin is a thermoset.

23. The method of any one of the preceding claims, wherein the method further comprises cooling the mould and/or demoulding the reinforced lightweight composite component.

24. The method of any one of the preceding claims, wherein the method further comprises: applying a finish layer to the reinforced lightweight composite component, optionally by using an autoclave process.

25. The method of any one of the preceding claims, wherein the reinforced lightweight composite component is a car seat, or a part therefor.

Description:
Method of Manufacturing Reinforced Lightweight Composites

Technical Field

The present invention relates to a method of manufacturing reinforced lightweight composites and to reinforced lightweight composites manufactured according to said method. More particularly, the present invention relates to a Resin Transfer Moulding (or, “RTM”) method of manufacturing reinforced lightweight composite components which are reinforced at the edge, and to reinforced lightweight composite components manufactured accordingly, such as essentially two-dimensional or shell-like reinforced lightweight composite components, such as composite shells for passenger seats, or the like.

Background

Resin T ransfer Moulding (RTM) refers to a closed-mould method of manufacturing composites wherein, initially, fibres are disposed on a lower mould, then an upper mould is closed onto the lower mould and, finally, a resin mixture is injected through the mould into a mould cavity defined between the lower and upper moulds, which cavity contains said fibres ready for impregnation.

The fibres may be in the form of a woven cloth, but other fibre packs or fibre lay-ups are equally possible. Once the resin is cured, the mould is opened, and the composite component can then be demoulded ready for use or subsequent manufacturing operations. RTM is therefore a method that may be used to manufacture composite components quickly and efficiently, thereby reducing costs.

As more and more mechanical components have been identified as suitable candidates for manufacturing using RTM, engineers have tried to adapt RTM to achieve required mechanical performance. This has been the case, for example, for generally, or predominantly, two- dimensional or shell-like components, i.e. components that mostly extend across a planar or curved surface.

One area of particular concern with the above type of components when produced using RTM is mechanical stiffness at the edge. These concerns have limited the suitability of RTM for the manufacturing of composite structural components, i.e. components designed to transmit significant loads despite their light weight. l Manufacturers have successfully resolved the above problem by using ‘open-trench’ cross- sectional designs around the edges of such components. These designs do offer at least a degree of localised three-dimensionality, at the periphery, which increases stiffness. However, the unavoidable edge recesses may not always be acceptable from a technical, aesthetical and/or regulatory point of view, depending on the category of the components, and their ultimate applications and related norms and/or standards.

US 2013/0127092 A1 discloses moulded multilayer plastics components with continuously reinforced fibre plies, and a process for producing these components. Each component has a sandwich structure that comprises an internal reinforcement, that may be made of a foam material, embedded between two or more outer plies of fibre composite plastic. Around the periphery, the component has a coherent edge made of fibre reinforced plastic formed through peripheral overdimensioning of at least one of the fibre plies with respect to the internal structure.

Accordingly, there is still an outstanding need for peripherally stiffened composite structural components manufactured using RTM which avoid open-trench or recessed cross sections at the edge.

Overview of the Invention

There is disclosed a method of manufacturing an edge-reinforced lightweight composite component.

The method comprises (a) providing a fibre preform on a first mould surface, wherein said fibre preform comprises a first portion for reinforcing the composite component (i.e. a first reinforcement portion) comprising a reinforcement filler disposed at an edge region of the fibre preform, and a second, non-reinforced portion that conforms to the first mould surface.

With the term ‘preform’, we intend any arrangement of fibres with and filler that have been adequately prepared as described herein on the first mould surface in readiness for impregnation using RTM.

The method may thus further comprise, in some implementations, disposing one or more layers of fibres on the first mould surface of a first mould part. It will be understood that said fibres may take any suitable description. For example, said fibres may be an essentially two- dimensional cloth (such as a woven or non-woven cloth), or a three-dimensional stack or layup comprising multiple such layers. Other fibre packs would however be equally possible. For example, in one implementation, three fibre layers each in the form of a fibre mat may be disposed one on another to form a three-layer lay-up.

The first mould part may be, for example, a lower mould half, which may be particularly practical for the advantageous use of gravity for disposing the fibres. However, other possibilities are contemplated.

The method may also comprise disposing the filler on said fibre layer, mat or lay-up, the filler being adapted to provide localized edge reinforcement to the ultimate composite component.

The filler does not necessarily need to provide reinforcement in light of its own mechanical properties. This would be the case, for example, if the filler was made of metal or other strong material with mechanical properties. The filler, as will be describe below, only needs to provide an element around which fibres can be wrapped, so as to confer to the composite component a localised level of three-dimensionality yet avoiding a recessed or open-trenched design.

The filler - which will be of any suitable construction and shape, for example an expandable foam, or any other suitable structure or material - must not be disposed across substantially the whole layer or layers of fibres, that is across the whole area of the mould surface of the first mould part, as instead would have been the case, for example, for a wholly reinforced, layered composite structure. Here, the filler is intended to reinforce only a region of the finished component, which region will be reinforced only in correspondence of the filler, i.e. where the filler is present, at or close to the edge of the finished component.

Since the fibres (whether in the form of a mat, single layer or multi-layer lay-up) are disposed on the first mould surface, the resulting fibre preform (that is the fibre arrangement disposed on the mould in readiness for impregnation by RTM) will generally mainly extend across two dimensions (except in correspondence of the filler, which provides a localised three- dimensional shape to the composite component). It will be understood that the reinforcing filler may accordingly be provided in the form of a lump or lumps of material, or in the shape of, just as an example, one or more one-dimensional structures, such as a rope, a line or the like. Other forms or configurations, however, will be possible. In some implementations, the method may also comprise forming a fibre loop around said reinforcing filler. To form this loop, it is possible, for example, to wrap a portion (for example a peripheral portion) of the fibres around the reinforcement filler. For example, a portion of a fibre mat, or fibre layer or multi-layer fibre lay-up may be wrapped around the filler. Alternatively, new fibres could be used.

The loop of fibres around the filler will be preferably continuous, that is the filler will be completely embedded into fibres. However, the filler could otherwise be only partially wrapped with fibres. Likewise, it is not necessary that the whole length of said edge of the composite component be so reinforced.

The method also comprises (b) disposing a second mould surface relative to the first mould surface, such that a mould cavity is defined between the first and second mould surfaces, wherein the second mould surface comprises first, and second mould surface areas adapted to conform, respectively, to the first and second portions of the fibre preform, wherein the second mould surface area also conforms to the first mould surface.

In some implementations, the method may comprise disposing a second mould part relative to said first mould part, such that the mould cavity is defined between said first mould surface of the first mould part and a second mould surface of said second mould part, said mould cavity containing said fibre loop and filler, and at least a remaining portion of said fibres.

The method also comprises (c) transferring a mixture into said mould cavity, said mixture comprising a resin and a curing agent, and allowing said mixture to impregnate said first and second portions of the fibre preform. It will be appreciated that many different resins (such as epoxy resins) and curing agents are possible, as known in the arts of RTM. It will be important to achieve a viscosity of the mixture that allows the mixture to properly impregnate the fibres, but this aspect too is known from the RTM arts.

The finished edge-reinforced composite component will thus present a reinforced region as well as a non-reinforced region in connection with the remaining portion of the fibres. This is in the interest of manufacturing a component which is light in weight, yet sufficiently strong at the edge, to provide structural performance to said component.

Other aspects of the present disclosure are set out in the accompanying claims. The present invention is defined in accordance with claim 1. Brief Description of the Drawings

Illustrative implementations of the concepts described herein will now be described, purely by way of example, in connection with the attached drawings, in which:

Figure 1 represents a fibre lay-up on a lower mould half in accordance with the prior art;

Figure 2 shows an upper mould half closed on the lower mould half of Figure 1 , also according to the prior art;

Figure 3 represents a fibre lay-up on a lower mould half in accordance with the present disclosure;

Figure 4 shows a reinforcing filler deposed on the fibres of Figure 3;

Figure 5 shows the creation of a loop of fibres around the filler of Figure 4;

Figure 6 shows an upper mould half closed on the lower mould half of Figures 3, 4 and 5;

Figure 7 represents the injection of a resin mixture into a cavity of the closed mould of Figure 6, and the resin mixture’s subsequent heating;

Figure 8 shows a method of applying a surface finish to a reinforced lightweight composite component manufactured according to the method shown in Figures 3-7;

Figure 9 shows a demoulded edge-reinforced lightweight composite component manufactured as described herein;

Figure 10 is a comparison between cross sections of similar components manufactured using a standard autoclave method (Figure 10A), a standard RTM method (Figure 10B) and the presently disclosed RTM method (Figure 10C); and,

Figure 11 shows a sport car seat comprising composite components manufactured as described herein:

Figure 11 A is a partial, front perspective view of a portion of the seat; Figure 11 B is a top plan view of the seat of Figure 11 A;

Figure 11C is a cross section representation of the seat of Figures 11A and 11 B according to plane A-A of Figure 11 B; and,

Figure 11 D is a cross section representation of the seat of Figures 11 A, 11 B and 11 C along plane B-B of Figure 11B (all the stated radius dimensions are in mm, and the drawings are not to scale).

Throughout the description and the drawings, like reference numerals refer to like features. Description

Figures 1 and 2 represent a conventional RTM method for manufacturing a lightweight, edge- reinforced composite component. A fibre preform 11 , in this case consisting of a fibre cloth 16 of substantially uniform thickness, is accommodated on a first mould surface 31 provided on a first mould half 34, as shown in Figure 1. There is a mechanical requirement for the finished product 2 (this is visible in Figure 10) to have increased mechanical stiffness around an edge. To stiffen this edge, the first mould half 34 has been provided with a recessed design. Accordingly, an edge portion 17 of the fibre cloth 16 can be accommodated on a recess 37 formed by the first mould surface 31.

Turning now to Figure 2, an upper mould half 35 is then disposed on the first mould half 34 to form a mould cavity 33 around the fibre cloth 16 forming the fibre preform 11 - as shown. The mould cavity 33 is provided so as to receive a resin mixture 40 (shown in Figure 7) through a transfer channel 36 which, in this case, is formed on the upper mould half 35 (but could be located elsewhere, for example on the lower mould half 34, or this channel 36 could alternatively have been defined or provided between the two different mould parts 34, 35). The cavity 33 is bound by the first mould surface 31 introduced above in connection with Figure 1, and by a second mould surface 32 provided on a lower face of the upper mould half 35.

As it can be appreciated from Figure 2, in this conventional RTM method, the second mould surface 32 is generally shaped to conform to the first mould surface 31 (including its recess 37) and, accordingly, the fibre preform 11 , as disposed on the first mould surface 31. The first and second mould halves 34, 35 are secured together (for example by using a set of clamps, but other manners are equally possible), but these details are of no importance to the present disclosure and will therefore not be described further. Once the mould halves are secured, the resin mixture 40 can be transferred to the cavity 33 through the transfer channel 36. The final product 2 is shown in Figure 10B. This is a reinforced lightweight composite component 2 which exhibits an open trench OT on at least one of its edges. The open-trenched portion OT of the edge of the composite component 2 has a generally three-dimensional extension or envelope (as opposed to the remainder of the component 2, which instead is essentially two- dimensional), which, as such, can better resist forces, especially bending moments acting out- of-plane.

Producing reinforced lightweight composite components 2 with an open-trenched design at the edge using conventional RTM techniques as described in connection with Figures 1 and 2 is cost-effective, and this can lend these fabrication methods to mass production. However, the open-trench OT may not be acceptable in some applications for various reasons, including aesthetic appeal or adherence to regulation. The inventors have therefore set out to solve this challenge, while maintaining all or most of the advantages of conventional, open-trench RTM.

Referring now to Figures 3 to 5, there are shown preparations for carrying out an improved RTM method which disposes of the issues related to the open-trench OT described above. With reference to Figure 3, there is shown a fibre mat 16 similar to that described in connection with Figures 1 and 2. Other similar features shown in Figure 3 are the first mould half 34, and the first mould surface 31 and its recess 37, so these features will not be described further. It is noted, however, that the recess 37 in the first mould half 34 of Figure 3 is different than the recess 37 in the first mould half 34 of Figures 1 and 2. Also, it will be appreciated that the fibre mat 16 has, with respect to the fibre mat 16 of Figures 1 and 2, some additional length at the edge region 17, and that in this edge region 17 the thickness of the fibre mat 16 narrows slightly compared to the thickness of the remainder of the fibre mat 16. It is equally possible that said thickness be unchanged, or it could increase. The additional length at the edge region 17 is so that the fibre mat 16 may receive, after the fibre mat 16 has been disposed on the first mould surface 31, a reinforcement filler 13, which in the described implementation is in the form of a length of a material, in this case a foam (but other materials can in principle be used, such as a rope or the like) - as shown in Figure 4.

Referring now to Figure 4, the filler 13 has in this case a circular cross section 14, but other cross-sectional shapes would however be possible. Likewise, the filler 13 does not need to be a length of material, but lumps or discrete portions of filler 13 may similarly be used. The filler 13 does not provide reinforcement through the whole structure, so as not to defeat the advantages of conventional RTM (that is, to maintain lightness). Most of the composite component manufactured as described herein is according to conventional RTM, except for the reinforced edge. Figure 4 shows the filler 13 in association with the fibre mat 16, and the recess 37 defined by the first mould surface 31. Multiple fibre mats could however likewise be used, depending on the required structural performance of the component.

The recess 37 of the first mould surface 31 is sized and shaped to receive the filler 13. Accordingly, depending on the size and shape of the filler 13, and its cross section 14, the recess 37 may take different shapes. It is not necessary for this shape to be constant along the edge region 17 of the fibre mat, since variations are possible and indeed contemplated, depending on the applications. Disposition of the filler 13 on the fibre mat 16 defines first and second fibre preform portions 12, 22. The first fibre preform portion 12 is located at the edge region 17 of the fibre mat 16, and the second fibre preform portion 22 instead comprises, in this case, all the rest of the fibre mat 16. However, it will be understood that there is no requirement for this second fibre preform portion 22 to extend to comprehend the total of the remainder portion of the fibre mat 16.

Turning now to Figure 5, the additional length of fibre mat 16 is folded backwardly from the position shown in Figure 4 to - in this occurrence - completely wrap, surround and therefore cover the filler 13, as shown. However, in different implementations, the filler 13 may only at least partially be wrapped or surrounded by fibres. Likewise, it is not mandatory that the same fibre mat 16 be used, but new fibres could be added for at least partially wrapping or surrounding the filler 13. The order of these operation can be reversed, in that first it would be possible to dispose fibres for wrapping around the filler, once the filler has been disposed on the lower mould half, and then additional fibres could be laid on the lower mould half. For example, three layers of fibres could be used to make the composite component, in addition to the fibres that are used to wrap around the filler. Returning, however, to the present implementation, a loop 18 is defined by the fibre mat 16 by folding the fibre mat 16 at the edge region 17 over the filler 13. A distal end 19 of the fibre mat 16 is folded backwards over the filler 13 until it abuts the fibre mat 16 at an abutment 20. Here, the filler 13 is completely enclosed and embedded into fibres - but partial embedment is a possibility at other places along the edge region 17 of the fibre mat, or the filler may be completely enclosed so as not to be longer visible, depending on the application.

In this implementation, the loop 18 comprises a gap G to allow expansion of the filler 13 with heat H, as will be described further below. Expansion of the filler 13 with temperature may be advantageous, because the expanded filler 15 (see, for example, Figure 8) can then provide adequate support to the incoming resin mixture 40 around the whole internal surface of the fibre loop 18, such that there are no gaps in the finished product, and thus no weakness points. It is of course possible to use fillers that have controlled expansion rates at the relevant moulding temperatures. Figure 5 shows the preform 11 ready for impregnation, according to the method described herein.

Figure 6 shows the disposition of an upper mould half 35 on the lower mould half 34, in principle similar to the arrangement shown in Figure 2. Like features, accordingly, will not be repeated. However, with the upper mould half in place, it is now possible to distinguish on the second mould surface 32 two distinct mould surface areas, which we refer to as first and second mould surface areas 32a, 32b, respectively. The first mould surface area 32a is associated with the first fibre preform portion 12, and the second mould surface area 32b is associated with the second fibre preform portion 22, as shown. The first mould surface area 32a is designed and shaped to accommodate the fibre loop 18, and the filler 13, while the second mould surface area 32b is essentially as in the prior art, that is it is simply designed to accommodate the fibre preform 11 , and thus conforms to the fibre preform 11 and the first mould surface 31, at those locations.

As previously described, once the mould halves 34, 35 are suitably clamped, a resin mixture 40 can be poured - with or without the help of a positive pressure applied externally of the mould 30 - into the mould cavity 33 directly through the transfer channel 36. The cavity 33 is now shaped according to the first and second mould surfaces 31, 32 to accommodate the reinforcing filler 13 at one edge of the finished product. The resin mixture then impregnates the fibres in the cavity 33, as shown in Figure 7.

Figure 7 schematically shows the transfer of the resin mixture 40 into the cavity 33 of Figure 6. The features that have already been described above in relation with Figure 6 will not be described again. The resin mixture 40 is made up of a resin 41 and a curing agent 42, as known in the arts of RTM. In this implementation, a positive pressure P is imparted to the resin mixture 40 outside of the mould 30, for example by a pump (not shown). Alternatively, or additionally, a vacuum pump could be applied to the cavity 33, for example through the separation between the lower and upper mould halves 34, 35. It is not necessary that the resin mixture 40 be premixed. The resin 41 and the curing agent 42 could be mixed locally, just before the mixture is injected into the cavity 33, as schematically represented in Figure 7, or they could in principle mix in the cavity, although this is less preferred. A heater H is operatively coupled to the lower mould half 34 (but this could be equally applied to upper mould half 35) to heat the mould 30, thereby helping the transfer of the resin mixture 40 as well as the curing of the resin mixture 40 in the mould 30, if necessary. A number of heaters H may be used in place of the single heater H of Figure 7, and any of these heaters may operate according to different principles, for example conduction and/or convection. However, these details are not relevant to the present disclosure. The filler material, however, may need to be adequately specified to provide an intended level of expansion at the moulding temperatures. Also, the one or more heaters H will be selected and operated accordingly.

The demoulded reinforced lightweight composite component is, in this implementation, finished with the application of a number of aesthetic layers 50 of a thin carbon composite (skin). This is done, as shown in Figure 8, by first wrapping the layers 50 around the demoulded part, using a suitable adhesive, which may be a different adhesive or the same resin mixture 40 used in the RTM method described herein. Curing may be favoured by increased temperatures as well as by pressure obtained by placing the demoulded part in a vacuum bag VB, as also shown in Figure 8, wherein a vacuum V is formed by a vacuum pump (not shown) operatively connected to the vacuum bag. The details of this step are not relevant to this disclosure and are therefore not provided herein. However, by using this vacuum bag technique it is possible to obtain aesthetically finished components 10, one of which is shown in Figure 9. It will be noted that Figures 8 and 9 show the expanded filler 15, inside the resin impregnated fibre loop 18. The application of the skin may be preceded by sandblasting, if required.

Figure 9 shows a finished reinforced lightweight composite component 10 manufactured using the improved RTM method described herein. This component 10 comprises an edge- reinforced section 10a as well as a non-reinforced section 10b. The reinforced section 10a has an increased edge stiffness comparable to that of an equivalently reinforced portion 2a of the prior art component 2 which was previously briefly described in connection with Figures 1 and 2 and is shown in Figure 10B. However, the presently disclosed component 10 does not comprise an edge featuring an open trench OT, as the other component 2, but an edge defined by a ‘close trench’ CT, as shown in Figure 10C. The components 2, 10 are manufactured for the same application, i.e. as carbon composite parts of a vehicle seat S, which is shown in Figure 11. Importantly, the two non-reinforced portions 2b, 10b of the two respective composite components 2, 10 being compared are generally equivalent in terms of mechanical performance. The composite component 10 described herein retains the advantages of conventional RTM forming (that is the ability to achieve good structural properties while maintaining ease of manufacture and therefore relatively low cost) throughout most of its structure, while it greatly improves the shape of the stiffened edge.

For completeness, Figure 10A also shows an equivalent car seat composite component 1 manufactured using a standard autoclave process. The finish layer 50 may be disposed around a foam core, as shown in Figure 10A. However, other principles may be followed to allow for a hollow cavity, where needed. This prior art method results into components 1 which may be too expensive to produce, since this method, as it can be appreciated, is not really suitable to mass production. However, autoclave manufacturing would be able to confer to these components the required lightness and strength, the latter typically by laying up multiple layers.

On the other side, the open trench component 2 achieved using conventional RTM lends itself to the production of robust, light weight structures, which however may not be acceptable due to the presence of the open trench OT, as discussed. The advance presently described is in relation to the provision of the close trench CT in the composite component 10 of Figure 10C. The close trench CT is acceptable in shape in that does not result into sharp edges, and still provides the required localised stiffness at the edge-reinforced portion 10a of the reinforced component 10. The (non-reinforced) remainder 10b of the component 10 is essentially left unchanged compared to the component 2 obtained using convention RTM.

Finally, Figure 11 shows a car seat S comprising one or more carbon composite components 10 manufactured according to the method described herein. Figure 11A is a front partial perspective view of the seat S showing a portion of the entire seat S, while Figure 11 B is a top plan view of the same seat S. The seat S comprise two or more parts 10 each manufactured according to the RTM method described herein. This can be better appreciated from Figures 11 C and 11 D, which correspond, respectively, to cross sections according to planes A-A and B-B, respectively, shown in Figure 11 B. The curvature radii R quoted in Figures 11 C and 11 D are expressed in mm, and, as it can be seen, range from a minimum of 5mm in connection with the edge-reinforced portions 10a of the composite components 10. This means that the seat will not need extensive padding (as in prior art seats) in order to satisfy relevant regulations. It is also worth noting the presence of an opening or window W in the car seat S, as shown in Figures 11 A, 11 C and 11D. This shows that the reinforced edge 10a of the composite component can equally be an external reinforced edge, provided on an external edge of the seat S, as well as an internal reinforced edge, provided on an internal or inner edge of the seat S.

Example

A car seat is manufactured by initially providing a lower mould half as described herein. The lower mould half defines a groove in correspondence of the edges of the finished composite component. A glass fibre layer is disposed on and across the groove, to exceed the width of the groove. Then, a foam filler is disposed all along the groove, over the glass fibre layer, which is then wrapped around the foam filler for the whole length of the groove so as to fully encapsulate the foam filler. At this point, three fibre mats are laid one on top of the other to form a three-layer fibre lay-up. A preform is thus ready for impregnation using RTM as described herein. An upper mould half is lowered on the lower mould half and a mould cavity is formed which accommodated the preform. A resin mixture is poured into the cavity as also described herein. Finally, the composite component is demoulded and then is forwarded on for further manufacturing operations before being shipped for use.

The glass fibre initially disposed around the groove is the same as the first layer successively disposed on the lower mould half. This is woven glass fibre mat EBX450 supplied by Selcom Multiaxial Technology, a biaxial fabric having a weight of 450 g/m2. The second layer, which is disposed on the first layer, is woven carbon fibre mat GG 380 T supplied by Angeloni, having a weight of 384 g/m2. This carbon fibre layer provides the required mechanical strength. The third layer disposed on the second layer is random-orientation non-woven glass fibre mat Uniconform 600 supplied by OVC Reinforcements, having a weight of 600 g/m2. The resin used in the RTM process is a high-performance epoxy vinyl ester resin Arotran 3101 supplied by Ashland, Inc..

The above detailed description describes at least one exemplary method of manufacturing a reinforced lightweight composite component. However, the described arrangements are merely exemplary, and it will be appreciated by a person skilled in the art that various modifications can be made without departing from the scope of the appended claims. Some of these modifications will now be briefly described. However, this list of modifications is not to be considered as exhaustive, and other modifications will be apparent to a person skilled in the art. In the above description, a mould has been described comprising two and only two mould halves arranged as a lower mould half and upper mould half, respectively. However, this arrangement is non-limiting and it will be appreciated that suitable moulds may comprise a different number of mould parts, and different mould part orientations.

Also, the above description refers to a fibre preform. With the term fibre ‘preform’ we intend any fibre or fibre-based material, or arrangement of materials, suitably prepared for RTM, that is any fibre material or arrangement which is capable of being impregnated by a resin mixture transferred to a mould cavity as known in the RTM arts and as described herein.

Further, it is noted that the term ‘filler’ has a functional connotation in that it indicates any materials capable of conferring suitable reinforcement to the finished composite component.

Further still, in the above description we refer to an edge ‘region’ of the fibre preform. It will be understood that with the wording ‘edge region’ we mean a portion of the fibre preform located at or toward a periphery of the fibre preform rather than at or in proximity of a centre of the fibre preform. It is by associating the filler with such an edge region of the fibre preform that it is possible to obtain a reinforced edge in the finished product, manufactured using RTM. Since the final product also has a non-reinforced portion obtained similarly to conventional open-trenched RTM, the final product is in addition lightweight and easy and cost-efficient for mass manufacture.

While various specific combinations of method steps have been described, these are merely examples. Method steps may be combined in any suitable combination. Method steps may also be omitted to leave any suitable combination of method steps in place.

The described method may be implemented using computer executable instructions. A computer program product or computer readable medium may comprise or store the computer executable instructions. The computer program product or computer readable medium may comprise a hard disk drive, a flash memory, a read-only memory (ROM), a CD, a DVD, a cache, a random-access memory (RAM) and/or any other storage media in which information is stored for any duration (e.g., for extended time periods, permanently, brief instances, for temporarily buffering, and/or for caching of the information). A computer program may comprise the computer executable instructions. The computer readable medium may be a tangible or non-transitory computer readable medium. The term “computer readable” encompasses “machine readable”.

The singular terms “a” and “an” should not be taken to mean “one and only one”. Rather, they should be taken to mean “at least one” or “one or more” unless stated otherwise.

The word “comprising” and its derivatives including “comprises” and “comprise” include each of the stated features but does not exclude the inclusion of one or more further features.

The above implementations have been described by way of example only, and the described implementations are to be considered in all respects only as illustrative and not restrictive. It will be appreciated that variations of the described implementations may be made without departing from the scope of the disclosure.

It will also be apparent that there are many variations that have not been described, but that fall within the scope of the appended claims.

List of References

1 Autoclave Composite Component (prior art

2 RTM Composite Component (prior art)

2a Reinforced Portion of Composite Component 2b Non-Reinforced Portion of Composite Component

10 Composite Component (manufactured according to the method described herein) 10a Reinforced Portion of Composite Component

10b Non-Reinforced Portion of Composite Component

11 Fibre Preform

12 First Portion of Fibre Preform (Reinforcement Portion)

13 Filler

14 Cross Section of Filler

15 Expanded Filler

16 Fibre Cloth or Mat

17 Edge Region of Fibre Cloth or Mat

18 Loop of Fibre Mat

19 Distal End of Fibre Mat

20 Abutment 22 Second Portion of Fibre Preform (Non-reinforced portion)

30 Mould

31 First Mould Surface

32 Second Mould Surface 32a First Mould Surface Area 32b Second Mould Surface Area

33 Mould Cavity

34 First Mould Half

35 Second Mould Half

36 Transfer Channel

37 Recess of First Mould Half

40 Mixture

41 Resin

42 Curing Agent 50 Finish Layer OT Open Trench CT Close Trench H Heater

VB Vacuum Bag P Pressure V Vacuum R Curvature Radius S Seat W Window




 
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