COMPRESSION RESIN TRANSFER MOULDING

TECHNICAL FIELD

The present disclosure relates to improvements in high pressure resin transfer moulding (HP-RTM) and high pressure compression RTM (HP-CRTM) particularly, but not exclusively, to a resin diffusion patch used in HP-(C)RTM processes. Aspects of the invention relate to a system for manufacturing fibre composite components comprising at least one fibre- containing material and at least one matrix material, the system comprising a mould, means for injecting a matrix material, and means for shielding or protecting the fibre material from the high pressure flow of matrix material at the point of injection of the matrix material, i.e. where the matrix material would otherwise first comes into contact with the fibre material and to a method of manufacturing fibre composite components comprising at least one fibre- containing material and at least one matrix material, the method comprising preforming a fibre material, placing the preformed fibre material into an injection mould, and injecting matrix material at high pressure into the mould, wherein the method comprises placing means for shielding or protecting the fibre material from the high pressure flow of matrix material onto the fibre material.

BACKGROUND

Original equipment manufacturers (OEMs) in particular in the aerospace and automotive industry are under pressure to reduce the weight of components of vehicles in order to, for example, help meet C0 ₂ emission requirements. Lightweight materials such as fibre composite materials and carbon fibre composite materials in particular, can contribute towards this weight saving goal.

Traditional fibre composite manufacturing techniques, such as resin transfer moulding (RTM), are slow and expensive. High pressure resin transfer moulding (HP-RTM) and high pressure compression RTM (HP-CRTM) were developed to increase the throughput of RTM. HP-RTM works by injecting resin at a relatively high flow rate into a closed mould that contains the preformed carbon fibre reinforcement (referred to as 'preform'). By contrast, HP-CRTM, also known as gap injection or wet compression, involves injecting resin into a partially closed mould containing the perform carbon fibre reinforcement, and then closing the mould. Whereas in HP-RTM the resin flows through the preform, in HP-CRTM the resin flows over the preform and is mechanically forced into the preform upon closing of the mould. In both cases the resin is then typically cured and the part demoulded.

Injection of resin at a high flow rate is necessary to reduce cycle times and avoid / reduce the risk of the resin curing during the course of the injection, especially for large parts where injection times can be relatively long. However, injection of resin at high pressure into preforms can cause a local movement of the fibre reinforcement material in the area of the injection point (e.g. in the region opposing the injection inlet), referred to in the art as fibre wash. As a result of the deformation of fibres by fibre wash during the injection process, fibre volume can be locally increased around or adjacent to the injection point, which may reduce permeability of the fibre material and can then require an increased injection pressure to maintain the desired flow of resin during moulding. If the increased pressure exceeds the safety cut out levels of the injection equipment, the injection fails and the partially injected part must be discarded. Where injection is able to proceed to completion, the fibre orientation in this region of the finished part can be incorrect.

The present invention has been devised to mitigate or overcome at least some of the above- mentioned problems.

SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a method of manufacturing fibre composite components using high pressure resin transfer moulding or high pressure compression resin transfer moulding, the method comprising providing a shielding or protecting device over a surface portion of a fibre-containing material, locating the fibre- containing material and shielding or protecting device in a mould, and delivering at least one matrix material into the mould through at least one inlet opening, wherein the shielding or protecting device is positioned over a surface portion of the fibre-containing material opposing the at least one inlet opening of the mould.

Advantageously, the shielding (or protecting) device may be located on the surface of the fibre-containing material so as to protect the fibre-containing material from the direct impact of the at least one matrix material when it is injected into the mould through the inlet opening.

According to another aspect of the present invention there is provided a system for manufacturing fibre composite components comprising at least one fibre-containing material and at least one matrix material using high pressure resin transfer moulding or high pressure compression resin transfer moulding, the system comprising a mould having at least one inlet opening, a means for delivering the at least one matrix material into the mould via the at least one inlet opening, and a shielding or protecting device located over at least a portion of the fibre-containing material in a region proximal to the at least one inlet opening.

By proximal it is meant that the shielding or protecting device is positioned close to the inlet opening of the injection port such that the first point of contact for matrix material entering the mould is the surface of the device, rather than the surface of the fibre composite. For example, the device is suitably positioned on the surface of the fibre composite opposite the inlet opening.

The fibre-containing material may be a preformed fibre-containing material. In embodiments, the fibre-containing material comprises a carbon fibre material, such as a carbon fibre fabric, it may be a carbon fibre preform.

The at least one matrix material is advantageously delivered to the mould by injection. In such embodiments, the pressure in the mixing head of the injection apparatus may be up to about 2.5x10 ⁷ Pa. In particular embodiments, the pressure inside the mould is between 2x10 ⁶ Pa and 1 .5x10 ⁷ Pa.

The matrix material may comprise a curable resin, for example, an epoxy resin.

In embodiments, the shielding device comprises a metal, a polymer, a reinforced polymer, or a fibre material. For example, the device may comprise aluminium and/or glass reinforced polytetrafluoroethylene. Advantageously, the device may comprise a low friction material. The device may comprise a low friction material on the surface of the device on which the matrix material flows as it is injected into the mould. In some embodiments, the shielding or protecting device is a film of material.

In some embodiments, the shielding device has a thickness of less than or equal to approximately 0.3 mm. For example, the device may have a thickness of about 0.1 mm.

In some embodiments, the shielding device is dimensioned in length and width such that the at least one matrix material can flow under the device to reach substantially the whole volume of fibre-containing material under the device. For example, the width of the protecting device may be between 1 cm and 30 cm, between 5 cm and 20 cm, or between 9 cm and 15 cm. In embodiments, the width of the shielding device is at least 2 cm.

In some embodiments, the shielding device is a substantially circular or elliptical sheet of material. The substantially circular sheet may have a diameter of about 10 cm ±1 cm. The substantially elliptical sheet may have a minor axis of about 10 cm ±1 cm.

Optionally, the method may further comprise securing the shielding device onto the fibre- containing material. In embodiments, securing the shielding device comprises applying an adhesive between the device and the fibre-containing material. Securing the shielding device may instead or in addition comprise stitching, tufting, or stapling the device onto the fibre- containing material.

Optionally, the method may further comprise removing the film from the finished composite component. In methods and systems of the invention the one or more matrix materials may be injected into the mould at any suitable rate and temperature. Thus, the rate of matrix material injection may be at least about 40 g/s, or at least about 50 g/s; e.g. between about 50 and 100 g/s; about 55 g/s, about 65 g/s, about 75 g/s, about 85 g/s or about 95 g/s. The temperature of the matrix material during injection of the material into the mould will be any temperature appropriate to maintain a desirable flow rate of the matrix material without degrading the material. For example, the material temperature may be between about Ι ΟΟ 'Ό and 130 °C, such as approx. 1 10 °C or approx. 120°C. All of the features discussed in relation to embodiments of the first aspect of the invention may be present, alone or in combination, in embodiments of the system according to this aspect of the invention. According to another aspect of the present invention there is provided a fibre composite component manufactured using the method of the first aspect or the system of the second aspect of the invention.

In a further aspect, the invention provides a vehicle comprising a fibre composite component manufactured using the method of the first aspect or the system of the second aspect of the invention.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is an example of a general resin transfer moulding process for the manufacture of fibre composite materials;

Figure 2 shows an example of a partially injected component where fibre wash has occurred;

Figure 3 shows a system for manufacturing fibre composite components according to embodiments of the invention; Figure 4 shows a means for protecting a fibre-containing material according to embodiments of the invention; Figure 5 is a flowchart for a method of manufacturing fibre composite components according to embodiments of the invention; and

Figures 6a and 6b show an example of a composite component manufactured according to the invention.

DETAILED DESCRIPTION

The following terms will be used throughout this document with the following intended meaning.

A 'component' is any item that can be manufactured by RTM, HP-RTM or HP-CRTM, and in particular using the systems and methods of the invention.

A 'film' or 'sheet' (both terms being used interchangeably throughout this document) is a piece of material that has two dimensions (width and length) that are substantially larger than the third dimension (referred to as thickness). In the context of the present invention, the thickness of a film will typically be described in micrometres to millimetres, whereas the other two dimensions are typically measured in millimetres to centimetres. The thickness of a film is typically substantially constant over the whole film, although local variations may be present, whether voluntary (e.g. texturing) or involuntary (e.g. local variations due to the manufacturing process of the film). Such variations will typically be small in relation to the average thickness of the film. The films according to the invention may take any suitable shape in the two dimensions other than thickness. For example, the film may be circular, elliptical, rectangular, or polyhedral. The terms 'width' and 'length' are loosely used herein to refer to the smallest and largest of these dimensions of a (piece of) film. In the case of a circular or square piece of film, the width and length will be substantially equal, whereas in the case of an elliptical piece of film, the width will correspond to the minor axis and the length to the major axis. The person skilled in the art would understand that the terms width and length as used herein do not necessarily refer to dimensions measured on perpendicular axes but rather generally refer to a long axis and a short axis within an arbitrary shape.

A film or sheet need not be flat and may be bent, curved or otherwise formed into any desirable shape, for example, to match the contour of a preform in the region of which it is to be used.

As used herein, a 'low friction material' refers to a material with surface properties such that the friction between the surface of the material and a matrix component flowing on the surface of the material is low. Such materials may include metals (e.g. aluminium), polymers (e.g. PTFE or glass reinforced PTFE), fibre materials (e.g. carbon or glass fibre mesh), etc. As the person skilled in the art would understand, the definition is relative and in practice a material should have low enough friction to allow flowing of the matrix material on the material surface at a rate sufficient to ensure filling of the injection mould according to the required specifications.

A 'fibre composite material' (also referred to as fibre reinforced composite) is a material that comprises at least one fibre-containing material and at least one matrix material. In the context of RTM, the fibre-containing material is typically known as a 'fibre preform'. In the context of RTM, the fibre-containing material may, for example, comprise carbon or glass fibre. The fibre-containing material may also be referred to as 'reinforcement', in reference to the fibre-containing material improving the mechanical properties of a fibre reinforced composite material compared to a material comprising only a matrix material, e.g. a simple plastic polymer.

A fibre preform is a fibre-containing material manufactured by weaving, knitting, braiding or stitching a fibre into a fabric, where the resulting three-dimensional fabric form is designed to conform to a specific shape. The manufacturing of a fibre preform may be done using any method known to the person skilled in the art, and is not described further here.

In the context of the invention, a matrix material is typically a resin that can be injected into a mould and then cured. Suitable resins include epoxy resins, polyurethanes, polyamides, or a variety of thermoplastic resins. Mixtures of materials may also be used. As the person skilled in the art would understand, the type of matrix material or matrix materials used may depend on the specific application for the component and/or any other requirements of the manufacturing process. The content of this disclosure is not limited to any specific type of matrix material provided that it is compatible with a RTM process.

The term 'resin transfer moulding' (RTM) refers to a manufacturing process whereby a liquid matrix material is injected into a mould containing a preformed fibre-containing material, such that the resin saturates the fibre preform. The preformed fibre-containing material may be a part shape dry (i.e. not yet impregnated with resin) carbon fibre fabric. The resin may then be cured, the conditions for which may depend on the type of resin used.

The term 'high pressure RTM' refers to applications of RTM where the pressure is up to about 250 bar (2.5x10 ⁷ Pa) in the mixing head and from about 20 bar (2x10 ⁶ Pa) to about 150 bar (1 .5x10 ⁷ Pa) inside the mould, depending on part size and geometry. Accordingly, injection flow rates of above 35 g/s may be used.

An 'injection point' as used herein may refer interchangeably to the location (on the mould) of injection of a matrix material into a mould (e.g. at the injection inlet port or orifice), and to the location on the fibre-containing material positioned within the mould (or equivalently the composite component in various stages of injection) at which the flow of matrix material would first contact the fibre-containing material upon injection. This would typically be the region of the fibre-containing material directly opposing the injection port inlet of the mould. An RTM apparatus may have more than one injection port. Thus, depending on the configuration of the RTM apparatus, one or more injection points may be used, and references to an injection point in this disclosure should be understood to encompass any number of injection points that may be present.

Figure 1 illustrates a resin transfer moulding process for the manufacture of fibre composite materials. A fibre-containing material in the form of e.g. a fabric 2, is inserted into a preform tool 4. The preform tool 4 may for example apply some heat and/or pressure to the fabric in order to obtain a (at least part) shaped fabric, referred to as a 'preform'. The fabric may, for example, be a carbon fibre fabric. The resulting preform 6 (also referred to as dry preform to distinguish from the preform post-resin injection) is then introduced into a mould 8. The mould 8 is closed and an injection apparatus 12 is used to inject a matrix material 10, such as a resin, into the mould. The resin 10 is injected into the mould 8, through an inlet / injection port 16, until it saturates the fibre preform, i.e. the preform does not contain any dry areas. The resin is then allowed to cure. The curing conditions (i.e. time, temperature, pressure, etc.) may depend on the type of matrix material(s) used. The finished composite component 14 is then removed from the mould, and may, in this form, or after further downstream processing (not described further herein) be used as a part for a vehicle 15.

High pressure RTM is a similar process to that shown in Figure 1 , but is performed by injecting the resin material at a higher pressure. Injection of the matrix components at higher pressure allows a higher flow rate of resin (for example rates of up to 200 grams per seconds may be achieved), in order to reduce the cycling time and enable the manufacture of relatively large parts, where there may otherwise be a risk of the resin curing during injection due to the large quantity of resin required. For example, pressures of up to about 250 bar (2.5x10 ⁷ Pa) in the mixing head of the injection device, and between about 20 (2x10 ⁶ Pa) and about 150 bar (1 .5x10 ⁷ Pa) inside the mould may be used. The person skilled in the art would understand that the exact pressures used may vary around the above quantities, for example, depending on the instrumentation used, geometry of the part, etc. High pressure compression RTM is a similar process to high pressure RTM, except that the resin is injected into a partially closed mould.

At the high pressures used in HP-(C)RTM, there is a risk that the highly energetic flow of matrix material may cause displacement of the fibres in and around the region where it first contacts the fibre-containing material. This is known as 'fibre-wash'.

Figure 2 illustrates a partially injected component in an HP-RTM or HP-CRTM process in which fibre wash has occurred. In the image the white arrow points to distorted fibres around the point opposing the inlet port of the mould, i.e. where the matrix was first injected onto the fibre preform). This problem is particularly prominent where the level of clamping (i.e. the clamping force exerted by the mould on the preform) is low. As a consequence, of this relatively lower clamping force, the fibre volume can increase locally around the injection point, and the permeability of the fibre-containing material is locally decreased. This local decrease in permeability means that in order to continue injecting the material at the necessary delivery speed, the pressure may need to be significantly increased. This increase may be such that it exceeds the safety cut out levels in the injection equipment, thereby causing an abortion of the injection process before the entire fibre-containing material is saturated. Additionally, even if the injection process is not aborted, fibre washing causes an incorrect orientation of the fibres in the composite component, thereby potentially altering the mechanical and/or aesthetic properties of the finished component.

In order to avoid such problems, it is known to create channels in the mould, referred to as 'runners'. Runners act to locally reduce the fibre volume in the relevant region of the mould and increase the permeability of the preform. However, this approach adds weight to the finished component by locally increasing the amount of matrix material on the surface of the component. Areas of low volume fibre and fibre distortion around these areas may also affect the mechanical properties of the finished product. The present invention therefore addresses the problems associated with fibre wash without requiring the use of such runners.

Figure 3 shows a system 18 for manufacturing fibre composite components according to embodiments of the invention. The embodiment shown on Figure 3 comprises a mould top part 8a, a mould bottom part 8b, a fibre containing material 6, and an injection apparatus 12 that is arranged to inject a matrix material 10 through an injection port 16. Additionally, the system comprises means 20 for shielding or protecting the fibre-containing material from the high pressure flow of matrix material where it first comes into contact with the fibre- containing material. The means 20 for protecting the fibre-containing material (e.g. a shielding or protecting device) may be in the form of a piece of material, such as a sheet or film. The sheet or film 20 is placed on the surface of the fibre-containing material 6 in the region or area below an inlet opening / orifice 22 in the mould (i.e. the sheet or film 20 is positioned over the fibre-containing material at least in the region located opposite the injection point for delivery of matrix into the mould). As a consequence, the sheet or film 20 acts as a first point of contact within the mould for the flow of matrix material 10 as it is injected, rather than the first contact point being the surface of the fibre-containing material 6. The matrix material flows onto and over the sheet or film 20 before contacting the fibre- containing material around and below the sheet or film 20. In this way, the sheet or film 20 dissipates some of the initial energy of the injection flow, thereby reducing or eliminating fibre wash. The matrix material 10 flowing on the film or sheet 20 can then impregnate the fibre-containing material 6. The pressure within the mould further acts to cause the matrix material 10 to flow and impregnate the sheet or film 20, not just around the sheet or film 20, but also under the sheet or film 20, so that the material 10 is fully impregnated. In embodiments, the resulting fibre composite component 14 may be a component for a vehicle 15, such as a car.

Figure 4 shows a means for shielding or protecting a fibre-containing material according to embodiments of the invention. In this embodiment, the means 20 is a circular sheet of metal. The material itself, or any coating or surface treatment on the surface of the sheet of metal may be any material that is compatible with the flow of matrix material over the surface of the sheet 20. Accordingly, the material may have a low coefficient of friction with a chosen matrix material. In this particular embodiment, the sheet material is aluminium. In other embodiments, however, any suitable material capable of forming a sheet or film may be used. In some embodiments, the sheet or film material may be a polymer. In some embodiments, the film material may be glass reinforced PTFE. In some embodiments, the film may comprise a carbon fibre fabric. In some embodiments, the film may comprise more than one material.

In the embodiment shown on Figure 4, the sheet is substantially circular with a diameter of about 1 1 cm and a thickness of about 0.1 mm. The dimensions of the shielding or protecting device, such as the sheet of Figure 4, may be determined on the basis of one or more of the properties of the mould, the fibre-containing material thickness and shape, matrix material and injection parameters. In particular, the thickness of the sheet (i.e. the dimension along the z-axis in Figure 4) may be limited by the clearance between the fibre-containing material and the inner surface of the mould in the region where the film is placed. For example, the film may have a thickness of up to about 0.25 mm. Excessive thickness may cause problems for the injection and/or may apply undesirable pressure on the fibre-containing material below, thereby locally reducing the fibre volume.

The thickness of the shielding or protecting device may also be limited on the lower bound by the requirement for the film to be able to withstand at least some of the energy of the injected matrix flow. Other practical considerations such as ease of manufacturing and use of the sheet or film and/or the means for shielding or protecting the fibre-containing material made from the sheet or film (e.g. cutting and placing the film on the fibre-containing material) may also be taken into account. For example, the shielding or protecting device of any embodiment may have a thickness of at least about 10 μηι. In embodiments, the shielding or protecting device (such as the sheet or film 20) may have a thickness of less than approximately 0.3 mm (±50 μηι): for example, a thickness between approx. 10 μηι and 0.3 mm (300 μηι), between approx. 50 μηι and 250 μηι, or between about 100 and 200 μηι. Small variations in the thickness of the sheet or film across its surface (e.g. ±50 μηι) may occur, such as due to irregularities in manufacturing or the positioning of the sheet or film on the fibre-containing material, with no material effect on the performance of the invention.

The shielding or protection device, e.g. sheet or film 20, may take any arbitrary or suitable shape in the x-y plane. For example, if there is a smallest dimension in this plane (loosely referred to herein as width), it may be any dimension that is compatible with the requirement to protect the fibre containing material adjacent the inlet opening of the injection port by providing an initial point of contact for matrix material within the mould; and by absorbing some of the energy of the injection flow, while allowing the flow of the matrix material to the fibre-containing material around and under the film. The design of the shielding or protection device may also depend on the particular conditions used in the injection moulding process, e.g. the shape of the part and/or mould, the nature of the matrix material, and the injection conditions. In embodiments, the width of the shielding or protecting device, such as film 20, may be at least 1 cm, at least 2 cm or at least 5 cm. In some embodiments, the width of the film may be a maximum of 15 cm, 20 cm or 30 cm. The largest dimension in this plane, where the dimensions are not the same in the x and y axes (loosely referred to herein as length) may be any suitable dimension, depending e.g. on the dimensions of the part on which the film is applied. In the embodiment of Figure 4, the film is circular and the width and length are therefore substantially equal. In this embodiment, the diameter of the circular film is about 1 1 cm. In some embodiments, however, the shielding or protecting device may be circular, elliptic, rectangular, square, hexagonal, polyhedral, or any other suitable shape. Dimensions of width and length may, thus, be any suitable length between, for example, approximately 1 cm and 30 cm; such as between approximately 5 cm and 20 cm or between 9 cm and 15 cm. Suitably, the film may be circular or elliptical with a diameter or minor axis of about 10 cm (±1 cm). Figure 5 is a flowchart illustrating a method of manufacturing fibre composite components according to embodiments of the invention. At step 100, a preformed fibre-containing material 6 is obtained. The manufacture of fibre preforms is known in the art and not described further here (see for example Reichwein et ai, "Light, Strong and Economical - Epoxy Fibre-Reinforced Structures for Automotive Mass Production", 10th-Annual SPE® Automotive Composites Conference & Exhibition, 2010, available at http://www.speautomotive.com/SPEA CD/SPEA2010/pdf/TS/TS8.pdf ; Hillermeier et al, "Advanced thermosetting resin matrix technology for next generation high volume manufacture of automotive composite structures", 10th-Annual SPE® Automotive Composites Conference & Exhibition, 2010, available at http://www.speautomotive.com/SPEA_CD/SPEA2012/pdf/TS/TS1 .pdf). The shielding or protecting device 20, such as a sheet or film material, is then placed onto the preform 6. This may be done manually or automatically. The location of placement of the sheet or film 20 on the preform will depend on the configuration of the RTM apparatus, and in particular on the location of the injection point (or points). As the person skilled in the art would understand, the configuration of the RTM apparatus itself may be dependent upon the shape and size of the preform. For example, the film 20 may be placed on the fibre-containing material 6 in such a way as to cover the location of the centre of the jet of matrix material at the injection point and, in addition, a given minimum distance around the centre of the jet. In some embodiments, the location of the shielding or protecting device and the location of the injection point may be coordinated in such a way as to position the device 20 at an advantageous location. In embodiments, an advantageous location may be in an area of the component that is removed in a later step of processing of the part. In some embodiments, the RTM apparatus may comprise multiple injection points, and a protecting device 20 may be placed at some or all of these injection points.

In some embodiments, the device 20 may additionally be secured 102b on the fibre- containing material 6. This may be done, for example, when the preform 6 needs to be transported, together with the shielding or protecting device, to an injection location in the manufacturing process. Securing the device 20 on the preform 6 may comprise applying an adhesive to the surface of the device 20 in contact with the preform 6, and/or to the preform. Suitable adhesives are chosen to be compatible with the matrix material. Securing the device 20 may instead or in addition comprise tufting, stitching or stapling the device 20 onto the fibre containing material 6. At step 104, the preform 6 is placed into the injection mould. Steps 102a (and 102b, if performed) may be performed before or after placing the preform 6 in the mould 8. The matrix material 10 is then injected 106 into the mould 8. This may include a terminal phase at increased pressure in order to force the matrix material 10 to flow under the device 20. When using compression resin transfer moulding, the mould will be closed (not shown) after injection of the resin. In these embodiments, a first pressure may be used in the injection phase, and a second (higher) pressure may be used in the compression phase. For example, a maximum in mould pressure of up to about 50 bar (5x10 ⁶ Pa) and about 120 bar (1 .2x10 ⁷ Pa) may be used, respectively in the injection and compression phase.

At step 108, the resin is cured. The curing parameters (time, temperature, pressure, etc.) may depend on the matrix material, the RTM apparatus and the component being manufactured. The particulars of this step are known in the art and are not described in detail here.

At step 1 10, the device 20 may optionally be removed from the surface of the fibre- containing material 6. Removing the device 20 for protecting the fibre-containing material from the finished composite component 14 may comprise removing the device 20 itself, and optionally any adhesive, from the surface of the finished component 14. Alternatively, the device 20 may be removed by removing a section of the finished component 14. This may be advantageous when e.g. a section of the component has to be removed, cut out, drilled out, etc. from the component in order for the component to perform its function. As mentioned above, in such embodiments, the RTM tool may be designed such that the injection point is placed over an area of the fibre-containing material that will eventually be removed in the final composite component. Removing the device 20 may be advantageous when the film material may be detrimental to the fibre composite. For example, when the film comprises aluminium it may for some applications be removed to avoid galvanic corrosion between the aluminium and the carbon fibre in the preform.

Examples

A fibre composite component designed to form part of the floor of a vehicle was manufactured using embodiments of the systems and methods of the invention. In particular, a steel RTM tool and a hydraulic press with 36,000 kN capacity were used to inject an epoxy resin into a non-crimp carbon fibre fabric. The resin was initially injected for up to 90 seconds at a flow rate of 55 g/s, at a temperature of 1 10 °C. The injection rate was increased in a subsequent trial to 85 g/s, using a temperature of 120 ^ and resulting in an injection time of up to 60 seconds. The resin was injected in a partially closed mould with a gap between 10% and 100% from the part nominal thickness. Four pressure sensors, at the extremities of the mould, were used to monitor the in-mould pressure during the injection cycle. When all four sensors reached a pressure of about 25 bar (2.5x10 ⁶ Pa) to 45 bar (4.5x10 ⁶ Pa), the injection process was stopped. A resin compression process was then performed in which the hydraulic press was programmed to close the gap to the nominal thickness of the part in about 5 to 15 seconds. The maximum internal mould pressure in the compression phase was regulated by a passive pressure buffer system designed inside the mould, to a value between 90 bar (9x10 ⁶ Pa) and 120 bar (1 .2x10 ⁷ Pa). The cure time was approx. 8 minutes for the injection process performed at a temperature of 1 10°C, and approx. 5 min for the injection process performed at a temperature of 120 'Ό.

A circular aluminium film of about 0.1 mm thickness and about 1 1 cm diameter was used as a shielding or protecting device. Figures 6a and 6b show a portion of the resulting component C, with the shielding / protective device in the form of a circular aluminium sheet 20 still attached to the component C (as shown in Figure 6a); and after removal from the component C (as shown in Figure 6b). Compared to the component shown on Figure 2, it can be seen that the fibre structure of the component around the point of first contact between the injected matrix and the shielding device I was essentially unaltered, i.e. no distortion of the fibres can be seen in Figure 6b. In this example the fibre-containing material was injected to saturation, leading to a well consolidated laminate. X-ray testing (results not shown) was used to examine the structure of the composite and the resin saturation under the patch, confirming the visual assessment. Many modifications may be made to the above examples without departing from the scope of the present invention as defined in the accompanying claims.