Method of manufacturing a composite part

Abstract

A method of manufacturing a composite part 108, providing a composite consolidating apparatus 200 comprising a chamber 216 and a heatable body 212 that at least partially surrounds the chamber; and wh

Description

BACKGROUND This invention relates to a method of manufacturing a composite part. It is known to manufacture parts from composite materials - such as fibre-reinforced composite (FRC) materials. Such materials typically comprise reinforcing fibres embedded within a matrix. As an example, the reinforcing fibres could be carbon fibre (CF) strands and the matrix material could be an epoxy resin. The skilled person would be aware of numerous other FRC materials that have alternative reinforcing fibre and matrix material combinations. A composite part can be manufactured by laying up reinforcing fibres on a contoured forming surface of a mould. The mould may be referred to as a “rigid mould tool”. The mould may be referred to a “moulding skin”. The contoured forming surface of the mould defines the exterior shape of the composite part that is to be manufactured. The reinforcing fibres may be in the form of a mat of reinforcing fibres. The reinforcing fibres may be pre-impregnated with a resin. In some examples, different types of reinforcing fibre mat can be laid up on the mould to form a composite part, with specific types of mat located and / or oriented specifically relative to each other in a way that strengthens the composite part against the stresses expected to be imposed on it in use. A vacuum bag may be placed over the composite part laid up on the mould. Drawing a vacuum around the composite part enables equal distribution of pressure across the composite part in the following consolidating step. An absorbent material (sometimes referred to as a “breather”) may also be placed over the composite part within the vacuum bag so as to facilitate easier removal of air, and to absorb any excess resin that may bleed out of the composite part during the following consolidating step. Consolidating the composite part includes curing the resin comprised by the composite part in order to form the matrix, and causing the composite part to conform to the contoured forming surface of the mould. This is typically achieved using an autoclave. Figure 1 shows a cross-sectional view of a typical autoclave. In Figure 1, autoclave 100 comprises an autoclave chamber 101, a convection heat exchanger 102 and a pressurisation mechanism 106. Figure 1 also shows a composite part 108 laid up on a mould 110, that has been placed within the autoclave chamber 101. Typically, composite part 108 is placed within autoclave chamber 101 whilst the temperature and pressure within the autoclave chamber 101 are at room temperature (e.g. 20°C to 30°C) and atmospheric pressure (e.g. around 100kPa). After placing composite part 108 within autoclave chamber 101, the temperature and pressure within the autoclave chamber 101 are increased to be within temperature and pressure ranges suitable for consolidating the composite part. For example, the temperature may be increased to a temperature within the range of 50°C to 600°C, and the pressure may be increased to a pressure within the range of 400kPa to 2000kPa-the specific temperature and pressure suitable for consolidating a particular composite part being dependent on the geometry of that composite part and the matrix material being used. The pressure within the autoclave chamber 101 can be increased by the pressurisation mechanism 106. The temperature within the autoclave chamber 101 can be increased by the convection heat exchanger 102 - which heats the gases within the autoclave chamber 101 and causes those heated gases to circulate (e.g. as illustrated by dashed line 104) within the autoclave chamber 101. It can take a relatively long time for convection heat exchanger 102 to increase the temperature within the autoclave chamber 101 from room temperature to a temperature suitable for consolidating the composite part - particularly as typical autoclaves used to consolidate composite parts often have large volumes of gas within their autoclave chambers. For example, in a typical autoclave 100, the convection heat exchanger 102 may be capable of increasing the temperature within the autoclave chamber 101 at a rate of 3°C per minute, such that increasing the temperature within the autoclave chamber 101 from room temperature to a temperature within the range of 50°C to 600°C takes between 10 minutes and just over 3 hours. The composite part can be consolidated by maintaining these elevated temperatures and pressures within the autoclave chamber 101 for a suitable period of time. The specific period of time suitable for consolidating a particular composite part will be dependent on the geometry of that composite part, the matrix material being used and the temperature and pressure within the autoclave chamber 101, as would be understood by the skilled person. Heat is transferred from the convection heat exchanger 102 to the composite part 108 by convection. The elevated temperature cures the resin by activating the resin’s chemical hardeners and solidifying the matrix around reinforcing fibres. The elevated pressure causes the composite part to conform to the contoured forming surface of the mould. After the composite part has been consolidated, the temperature and pressure within the autoclave chamber 101 are allowed to decrease to room temperature and atmospheric pressure. It can take a relatively long time for the temperature within the autoclave chamber 101 to decrease from a temperature suitable for consolidating the composite part to room temperature. For example, in a typical autoclave 100, the temperature within the autoclave chamber 101 may be allowed to decrease at a rate of 3°C per minute, such that decreasing the temperature within the autoclave chamber 101 from a temperature within the range of 50°C to 600°C to room temperature takes between 10 minutes and just over 3 hours. Once the temperature and pressure within the autoclave chamber 101 have reached room temperature and atmospheric pressure, the composite part 108 can be removed from the autoclave chamber 101. One or more further manufacturing steps - such as trimming, machining and / or surface finishing - may be performed after the consolidated composite part 108 has been removed from the autoclave chamber 101. This method of manufacture can be used to manufacture composite parts for use in automotive or aerospace applications, such as automotive bodywork parts or aircraft fuselage panels. That said, the relative long periods of time required for the temperature within the autoclave chamber 101 to be increased before consolidating a composite part, and subsequently decreased after consolidating that composite part, act as a bottleneck for this method of manufacture - limiting its throughput (e.g. number of composite parts that can be manufactured within a given period of time). This repetitive “thermal cycling” of the autoclave chamber 101 is also highly energy intensive - increasing the monetary and environmental costs associated with this method of manufacturing a composite part. As such, it would be desirable to have an improved method of manufacturing a composite part, e.g. that is less energy intensive and has a higher throughput. SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a method of manufacturing a composite part, the method comprising: providing a composite consolidating apparatus, the composite consolidating apparatus comprising a chamber and a heatable body that at least partially surrounds the chamber; and whilst the temperature of the body is maintained within a temperature range for consolidating the composite part: placing the composite part in the chamber; consolidating the composite part, wherein consolidating the composite part comprises transferring heat from the body to the composite part; and removing the composite part from the chamber. The method may further comprise increasing the temperature of the body to within the temperature range for consolidating the composite part before placing the composite part in the chamber. The method may further comprise maintaining the temperature of the body within the temperature range for consolidating the composite part after the composite part has been removed from the chamber. Consolidating the composite part may comprise curing a matrix material comprised by the composite part. Consolidating the composite part may comprise causing the composite part to conform to a contoured forming surface of a mould. Placing the composite part in the chamber may comprise placing the composite part and the mould in the chamber. The composite part and the mould may be placed in the chamber such that: the mould is in contact with the body; or the mould is in contact with one or more spacer elements, the one or more spacer elements being in contact with the body. The one or more spacer elements may comprise at least one spacer element having a contoured surface that corresponds to a non-forming surface of the mould. The one or more spacer elements may comprise at least one spacer element having a contoured surface that corresponds to a surface of the composite part. The method may further comprise adjusting the size of at least one of the one or more spacer elements in order to adjust the spatial relationship between the composite part and the body. Placing the composite part in the chamber may comprise placing the composite part, the mould and the one or more spacer elements in the chamber The method may further comprise selecting the one or more spacer elements from a plurality of spacer elements, the one or more spacer elements being selected in dependence on their size and / or thermal conductivity. Consolidating the composite part may comprise transferring heat from the body to the composite part by conduction. Consolidating the composite part may comprise transferring heat from the body, via the mould, to the composite part by conduction. Consolidating the composite part may comprise transferring heat from the body, via the one or more spacer elements and the mould, to the composite part by conduction. Consolidating the composite part may comprise transferring heat from the body to the composite part by radiation. The temperature of the body may remain substantially constant throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber. The temperature of the body may vary by less than 20°C throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber. The method may not comprise decreasing the temperature of the body between consolidating the composite part and removing the composite part from the chamber. The composite part may comprise a reinforcing material impregnated with a matrix material. The method may further comprise: placing the composite part in the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part; increasing the pressure within the chamber to within a pressure range for consolidating the composite part; consolidating the composite part whilst the pressure within the chamber is maintained within the pressure range for consolidating the composite part; decreasing the pressure within the chamber to below the pressure range for consolidating the composite part; and removing the composite part from the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part. The method may further comprise, after the composite part has been removed from the chamber: whilst the temperature of the body is maintained within the temperature range for consolidating the composite part: placing a further composite part in the chamber; consolidating the further composite part; and removing the further composite part from the chamber. There is also provided a method of consolidating a composite part, the method comprising: providing a composite consolidating apparatus, the composite consolidating apparatus comprising a chamber and a heatable body that at least partially surrounds the chamber; and whilst the temperature of the body is maintained within a temperature range for consolidating the composite part: placing the composite part in the chamber; consolidating the composite part, wherein consolidating the composite part comprises transferring heat from the body to the composite part; and removing the composite part from the chamber. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described by way of example with reference to the accompanying drawings. In the drawings: Figure 1 shows a cross-sectional view of a typical autoclave. Figures 2A to 2C show cross-sectional views of a composite consolidating apparatus according to the principles described herein. Figure 3 shows a method of manufacturing a composite part according to the principles described herein. DETAILED DESCRIPTION OF THE DRAWINGS The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. Figure 3 shows a method of manufacturing a composite part according to the principles described herein. In step S300, reinforcing fibres can be laid up on a contoured forming surface of a mould. The mould may be referred to a “rigid mould tool”. The mould may be referred to a “moulding skin”. The contoured forming surface of the mould defines the exterior shape of the composite part that is to be manufactured. In an example, the reinforcing fibres may be carbon fibre (CF) strands. The skilled person would be aware of numerous other suitable reinforcing fibres. The reinforcing fibres may be in the form of a mat of reinforcing fibres. The reinforcing fibres may be pre-impregnated with a resin. In an example, the resin may be an epoxy resin. The skilled person would be aware of numerous other suitable resins. As would be understood by a skilled person, a reinforcing fibre mat may comprise reinforcing fibres of any suitable length, woven together across any suitable number of directions, and pre-impregnated with any suitable amount of resin. In some examples, different types of reinforcing fibre mat can be laid up on the mould to form a composite part, with specific types of mat located and / or oriented specifically relative to each other in a way that strengthens the composite part against the stresses expected to be imposed on it in use. The mould may comprise multiple mould parts. The multiple mould parts may be assembled to define the contoured forming surface of the mould. Laying-up reinforcing fibres on the contoured forming surface of the mould may comprise: fully assembling the multiple mould parts; and laying up the reinforcing fibres on the contoured forming surface of the assembled mould. Alternatively, laying-up reinforcing fibres on the contoured forming surface of the mould may comprise: (1) partially assembling the multiple mould parts; (2) partially laying up the reinforcing fibres on the contoured forming surface of the partially assembled mould; and repeating steps (1) and (2) until the multiple mould parts are fully assembled and the reinforcing fibres have been fully laid-up on the contoured forming surface of the fully assembled mould. A vacuum bag may be placed over the composite part laid up on the mould. A vacuum bag may be attached to the contoured forming surface, or to a flange surrounding the contoured forming surface, in order to enclose the composite part between that vacuum bag and the contoured forming surface. Alternatively, the composite part and the mould could be placed within a vacuum bag in order to enclose both the composite part and the mould within that vacuum bag. Drawing a vacuum around the composite part enables equal distribution of pressure across the composite part in the following consolidating step. An absorbent material (sometimes referred to as a “breather”) may also be placed over the composite part within the vacuum bag so as to facilitate easier removal of air, and to absorb any excess resin that may bleed out of the composite part during the following consolidating step. In step S302, a composite consolidating apparatus is provided. The composite consolidating apparatus described herein may be referred to as an “autoclave” or a “cure oven”. The composite consolidating apparatus comprises a chamber and a body that at least partially surrounds the chamber. Figures 2A to 2C show cross-sectional views of a composite consolidating apparatus 200 according to the principles described herein. The composite consolidating apparatus 200 comprises a chamber 216 and a body 212 that at least partially surrounds the chamber 216. The body 212 may alternatively be referred to as a “housing”. The chamber 216 is an empty space defined, at least partially, by the body 212. The temperature of body 212 can be controlled, e.g. increased, maintained and, optionally, decreased. That is, the body 212 is heatable. The composite consolidating apparatus 200 may comprise means (not shown in Figures 2A to 2C, for ease of illustration) for heating the body 212 - e.g. one or more heating elements embedded within the body 212 and / or adjacent to the body 212. Examples of suitable heating means include, but are not limited to, electrical resistance heating elements, and fluid induction heating elements (such as oil induction heating elements). The body 212 may be made of a metal. The composite consolidating apparatus 200 also comprises a lid 214 - which may, or may not, be heatable. The composite consolidating apparatus 200 also comprises a pressurisation mechanism (not shown in Figures 2A to 2C, for ease of illustration). Figures 2B and 2C also show examples of spacer elements 218, 220 and 222 within the chamber 216 - as will be described in further detail herein. Returning to Figure 3, in step S304, the composite part 108 can be placed (e.g. positioned) in the chamber 216 of the provided composite consolidating apparatus 200 whilst the temperature of the body 212 is maintained within a temperature range for consolidating the composite part (e.g. a “consolidating temperature range”). In other words, the composite part 108 can be placed (e.g. positioned) in the chamber 216 of the provided composite consolidating apparatus 200 whilst the temperature of the body 212 is maintained within a temperature range for curing a matrix material comprised by composite part (e.g. a “curing temperature range”). That is, the terms “consolidating temperature range” and “curing temperature range” may be used herein interchangeably to refer to the same temperature range. For example, that temperature range may be any suitable range or sub-range within the overall temperature range of 50°C to 600°C. The specific temperature range suitable for consolidating a particular composite part is dependent on the geometry of that composite part and the matrix material being used - as would be understood by the skilled person. In a specific example for a particular composite part, the consolidating / curing temperature range may be 50°C to 600°C, preferably 70°C to 400°C, more preferably 90°C to 250°C, most preferably 110°C to 150 °C. That is, the composite part 108 is placed within the chamber 216 of the composite consolidating apparatus 200 whilst the body 212 is already at an elevated temperature (e.g. relative to room temperature). In other words, the temperature of the body 212 can be increased to within the temperature range for consolidating the composite part before placing the composite part in the chamber 216. This is unlike in typical autoclaving methods, in which composite parts are placed in the autoclave chamber whilst the temperature within the autoclave chamber is at room temperature. Placing the composite part 108 in the chamber 216 may comprise removing the lid 214 so as to access the chamber 216, placing the composite part 108 in the chamber 216, and subsequently replacing the lid 214. For example, the lid 214 may be hinged to the body 212. The lid 214 may comprise a heat insulated handle, to enable the lid 214 to be safely removed and replaced by an operator whilst the temperature of the body 212 is maintained within a temperature range for consolidating the composite part. Alternatively, the composite consolidating apparatus 200 may comprise an actuating mechanism that can automate the removal and replacement the lid 214 such that an operator does not need to interact with the lid 214 itself whilst the temperature of the body 212 is maintained within a temperature range for consolidating the composite part. The skilled person would be aware of numerous other ways in which the lid 214 could be designed to be safely removed and replaced whilst the body 212 is maintained within a temperature range for consolidating the composite part. As illustrated in Figures 2A to 2C, step S304 may comprise placing the composite part 108 and the mould 110 in the chamber 216. As illustrated in Figure 2A, the composite part 108 and the mould 110 can be placed in the chamber 216 such that the mould 110 is in contact with the body 212. Optionally, as illustrated in Figures 2B and 2C, the composite part 108 and the mould 110 can be placed in the chamber 216 such that the mould 110 is in contact with one or more spacer elements 218, 220 and / or 222, the one or more spacer elements 218, 220 and / or 222 being in contact with the body 212. That is, step S304 may comprise placing the composite part 108, the mould 110 and one or more spacer elements 218, 220 and / or 222 in the chamber 216. Alternatively, or additionally, one or more spacer elements 218 (e.g. adjustable spacer elements) may be comprised by (e.g. built into the body 212 of) the composite consolidating apparatus 200, and step S304 may comprise placing the composite part 108 and the mould 110 in contact with said one or more spacer elements 218. Alternatively, or additionally, when a series of like composite parts are being manufactured using the composite consolidating apparatus 200, one or more spacer elements 218, 220 and / or 222 used during the manufacture of a previous composite part may be left in the chamber 216 after that composite part has been removed from the chamber 216, and step S304 may comprise placing the composite part 108 and the mould 110 in contact with said one or more spacer elements 218, 220 and / or 222. The one or more spacer elements 218, 220 and / or 222 can affect the transfer of heat from the body 212 to the composite part 108. In some examples, referring to Figure 2B, in order to slow the transfer of heat from the body 212 to a certain region of the composite part 108, the composite part 108 and the mould 110 may be placed in contact with a spacer element 218 having a relatively large size (e.g. that can be used to establish a relatively large distance between that region of the composite part 108 and the body 212) and / or a relatively low thermal conductivity (e.g. being made from a “thermally insulating” material, such as ceramic). In order to speed up the transfer of heat from the body 212 to a certain region of the composite part 108, the composite part 108 and the mould 110 may be placed in contact with a spacer element 218 having a relatively small size (e.g. that can be used to establish a relatively small distance between that region of the composite part 108 and the body 212) and / or a relatively high thermal conductivity (e.g. being made from a “thermally conducting” material, such as metal). In an example, the difference in size (e.g. height) between a spacer element having a “relatively large size” and a “relatively small size” may be 5mm. The composite part 108 and the mould 110 may be placed in contact with multiple different spacer elements 218 in step S304. For example, certain regions of a composite part 108 may be thicker than other regions of that composite part 108, and so it may be desirable to both speed up the transfer of heat from the body 212 to the thicker regions of the composite part 108 and slow down the transfer of heat from the body 212 to the thinner regions of the composite part 108, e.g. so as to cause more uniform heating of the composite part 108 in the subsequent consolidation step. To achieve the desired rate of heat transfer between the body 212 and the composite part 108 (or the body 212 and different regions of the composite part 108), step S304 may further comprise selecting one or more spacer elements 218 from a plurality of spacer elements, the one or more spacer elements 218 being selected in dependence on their size and / or thermal conductivity. The plurality of spacer elements to select from may comprise numerous different spacer elements of different sizes (e.g. heights) and / or made from different materials (e.g. “thermally conducting” materials, such as metal, and “thermally insulating” materials, such as ceramic). Alternatively, or additionally, at least one of the one or more spacer elements 218 may be adjustable. That is, the size (e.g. height) of at least one of the one or more spacer elements 218 may be adjustable - e.g. by approximately 5mm. Step S304 may further comprise adjusting the size (e.g. height) of at least one of the one or more spacer elements 218 in order to adjust the spatial relationship between the composite part 108 and the body 212 (e.g. to increase or decrease the distance between the composite part 108, or certain regions of the composite part 108, and the body 212). In other examples, referring to Figure 2C, the one or more spacer elements may comprise at least one spacer element 220 having a contoured surface that corresponds to (e.g. conforms with, or fits together with) a non-forming surface of the mould 110. That is, as shown in Figure 2C, the spacer element 220 has an upper surface that corresponds to the lower surface of mould 110. Alternatively, or additionally, the one or more spacer elements may comprise at least one spacer element 222 having a contoured surface that corresponds to (e.g. conforms with, or fits together with) a surface of the composite part 108. That is, as shown in Figure 2C, the spacer element 222 has a lower surface that corresponds to the upper surface of the composite part 108. Placing the composite part 108 and / or the mould 110 in contact with said spacer elements 220 and / or 222 minimises the amount of empty space (e.g. gas) within the chamber 216. Said spacer elements 220 and / or 222 may be made of a material having a higher thermal conductivity than the gas within the chamber 216 - e.g. a “thermally conducting” material, such as metal. As such, placing the composite part 108 and / or the mould 110 in contact with said spacer elements 220 and / or 222 can speed up the transfer of heat from the body 212 to the composite part 108 and / or the mould 110. Further, minimising the amount of empty space (e.g. gas) within the chamber 216 reduces the total the amount of gas within the chamber 216 that is to pressurised whilst consolidating the composite part, which can have safety benefits. It is to be understood that, in some examples, one or more spacer elements 218 (as described with reference to Figure 2B) and one or more spacer elements 220 / 222 (as described with reference to Figure 2C) may be included within the chamber 216. For example, the composite part 108 and the mould 110 could be placed in the chamber 216 such that the mould 110 is in contact with a spacer element 220, the spacer element 220 being in contact with one or more spacer elements 218, the one or more spacer elements 218 being in contact with the body 212. In step S304, the composite part 108 can be placed (e.g. positioned) in the chamber 216 whilst the pressure within the chamber 216 is below a pressure range for consolidating the composite part 108. For example, the composite part 108 can be placed in the chamber 216 whilst the pressure within the chamber 216 is atmospheric pressure (e.g. around 100kPa). In step S306, the pressure within the chamber 216 can be increased to within a pressure range for consolidating the composite part 108 (e.g. a “consolidating pressure range”). In other words, the pressure within the chamber 216 can be increased to within a pressure range for causing the composite part 108 to conform to the contoured forming surface of the mould 110 (e.g. a “conforming pressure range”). That is, the terms “consolidating pressure range” and “conforming pressure range” may be used herein interchangeably to refer to the same pressure range. For example, that pressure range may be any suitable range or sub-range within the overall pressure range of 400kPa to 2000kPa. The specific pressure range suitable for consolidating a particular composite part is dependent on the geometry of that composite part and the matrix material being used - as would be understood by the skilled person. In a specific example for a particular composite part, the pressure may be increased to a pressure within the range of 400kPa to 2000kPa, preferably 475kPa to 1500kPa, more preferably 550kPa to 1000kPa, most preferably 600kPa to 650kPa. The pressure within the chamber 216 can be increased by a pressurisation mechanism (not shown in Figures 2A to 2C, for ease of illustration) comprised by the composite consolidating apparatus 200. The skilled person would be aware of numerous suitable pressurisation mechanisms. In step S308, the composite part 108 is consolidated (e.g. cured and, optionally, caused to conform to the contoured forming surface of the mould) whilst the temperature of the body 212 is maintained within the temperature range (as described herein) for consolidating the composite part (i.e. the consolidating I curing temperature range). In step S308, the pressure within the chamber 216 is also maintained within the pressure range (as described herein) for consolidating the composite part 108 (i.e. the consolidating / conforming pressure range). As described herein, the composite part comprises a reinforcing material (e.g. reinforcing fibres) impregnated with a matrix material (e.g. a resin). Consolidating the composite part 108 comprises curing the matrix material comprised by the composite part 108 - e.g. by using elevated temperatures to activate the resin’s chemical hardeners and thereby solidify (e.g. via the formation of cross-links) the resin around the reinforcing fibres. Consolidating the composite part also comprises causing the composite part 108 to conform to the contoured forming surface of the mould 110 — e.g. by using elevated pressures. The composite part 108 can be consolidated by retaining the composite part 108 within the chamber 106 for a suitable period of time whilst maintaining the elevated 14 temperatures and pressures described herein. The specific period of time suitable for consolidating a particular composite part will be dependent on many factors, including: the temperature at which the body 212 is being maintained; the geometry of the composite part 108; the matrix material comprised by the composite part 108; the thermal conductivity of any spacer elements 218, 220 and 222 positioned within the chamber 216; and the spatial relationship between the composite part 108 and the body 212 - as would be understood by the skilled person. A particular composite part 108 may require a threshold amount of energy to be transferred to its matrix material in order to cause that matrix material to solidify around its reinforcing fibres - e.g. in order to cause the formation of a sufficient amount of cross-linking within the matrix material. The period of time for which step S308 is performed may be the minimum period of time required to transfer that threshold amount of energy (i.e. in the form of heat energy) to the composite part 108. A suitable period of time can be determined through heat transfer modelling (e.g. in dependence on the factors listed above); or through simple trial and error by observing the material properties of like composite parts for which step S308 has been performed for different periods of time. By way of illustrative example only, as a result of the many factors described above, the suitable period of time could be any period of time within the range of 20 minutes to 40 hours. Consolidating the composite part 108 comprises transferring heat (e.g. heat energy) from the body 212 to the composite part 108. Unlike in typical autoclaving methods, according to the principles described herein heat can be transferred to the composite part 108 by conduction, convection and radiation. That is, step S308 may comprise transferring heat from the body 212 to the composite part 108 by conduction, convection and / or radiation. Referring to Figure 2A, in examples in which the composite part 108 and the mould 110 have been placed in the chamber 216 such that the mould 110 is in contact with the body 212, heat can be transferred from the body 212 to the composite part 108 by: conduction of heat from the parts of the body 212 in contact with the mould 110, via the mould 110, to the composite part 108; convection of gases comprised within the chamber 216 that are heated by the body 212; and radiation of heat from the parts of the body 212 not in contact with the mould 110 to the composite part 108. Referring to Figure 2B, in examples in which the composite part 108 and the mould 110 have been placed in the chamber 216 such that the mould 110 is in contact with one or more spacer elements 218, the one or more spacer elements 218 being in contact with the body 212, heat can be transferred from the body 212 to the composite part 108 by: conduction of heat from the parts of the body 212 in contact with the one or more spacer elements 218, via the one or more spacer elements 218 and the mould 110, to the composite part 108; convection of gases comprised within the chamber 216 that are heated by the body 212; and radiation of heat from the parts of the body 212 not in contact with the one or more spacer elements 218 to the composite part 108. Referring to Figure 2C, in examples in which the composite part 108 and the mould 110 have been placed in the chamber 216 such that the mould 110 is in contact with one or more spacer elements 220 and / or 222, the one or more spacer elements 220 and / or 222 being in contact with the body 212, heat can be transferred from the body 212 to the composite part 108 by conduction of heat from the parts of the body 212 in contact with the one or more spacer elements 220 and / or 222, via the one or more spacer elements 220 and / or 222, and optionally via the mould 110, to the composite part 108. In these examples, in which spacer elements 220 and / or 222 are shaped to minimise the amount of empty space (e.g. gas) within the chamber 216, the transfer of heat from the body 212 to the composite part 108 by convection and / or radiation may be limited (e.g. substantially prevented). During step S308, the temperature within the chamber 216, the temperature of the mould 110 and / or the temperature of the composite part 108 may be monitored - e.g. using any suitable temperature probe(s). Step S308 may be performed until a monitored temperature has reached a threshold temperature, and / or been maintained at or above a threshold temperature for a suitable period of time. Alternatively, step S308 may be performed for a predetermined period of time that does not depend on a monitored temperature - e.g. a period of time that has been determined through heat transfer modelling and / or trial and error, as described herein. After the composite part 108 has been consolidated, in step S310, the pressure within the chamber 216 can be decreased to below the pressure range (as described herein) for consolidating the composite part 108 (i.e. the consolidating I conforming pressure range). In step S312, the composite part 108 can be removed from the chamber 216 whilst the temperature of the body 212 is maintained within a temperature range (as described herein) for consolidating the composite part (i.e. the consolidating / curing temperature range). That is, the composite part 108 is removed from the chamber 216 of the composite consolidating apparatus 200 whilst the body 212 remains at an elevated temperature (e.g. relative to room temperature). That is, the method described herein does not comprise decreasing the temperature of the body 212 between consolidating the composite part 108 (in step S308) and removing the composite part 108 from the chamber 216 (in step S312). In other words, the temperature of the body 212 may remain substantially constant throughout placing the composite part 108 in the chamber 216 (in step S304), consolidating the composite part 108 (in step S308) and removing the composite part 108 from the chamber 216 (in step S312). Put another way, the temperature of the body 212 may vary by less than 20°C, preferably less than 10°C, more preferably less than 5°C, most preferably less than 1°C, throughout placing the composite part 108 in the chamber 216 (in step S304), consolidating the composite part 108 (in step S308) and removing the composite part 108 from the chamber 216 (in step S312). For this reason, the placing, consolidating and removing steps described herein may be referred to as a series of isothermal manufacturing steps. This is unlike in typical autoclaving methods, in which composite parts are removed from the autoclave chamber whilst the temperature within the autoclave chamber is at room temperature. Removing the composite part 108 from the chamber 216 may comprise removing the lid 214 so as to access the chamber 216, removing the composite part 108 from the chamber 216, and subsequently replacing the lid 214. In step S312, the composite part 108 can be removed from the chamber 216 whilst the pressure within the chamber 216 is below the pressure range (as described herein) for consolidating the composite part 108 (i.e. the consolidating / conforming pressure range). One or more further manufacturing steps - such as trimming, machining and / or surface finishing - may be performed after the consolidated composite part 108 has been removed from the autoclave chamber 101. The method may further comprise maintaining the temperature of the body 212 within the temperature range (as described herein) for consolidating the composite part (i.e. the consolidating I curing temperature range) after the composite part 108 has been removed from the chamber 216. That is, the method described herein may not comprise decreasing the temperature of the body 212 after removing the composite part 108 from the chamber 216 (in step S312). This can enable the manufacture of subsequent composite parts to be performed more quickly, and using less energy. That is, after the composite part 108 has been removed from the chamber 216, whilst the temperature of the body 212 is maintained within the temperature range (as described herein) for consolidating the composite part 108 (i.e. the consolidating I curing temperature range): a further composite part can be placed in the chamber 216 (e.g. by performing step S304 as described herein); the further composite part can be consolidated (e.g. by performing step S308 as described herein); and the further composite part can be removed from the chamber 216 (e.g. by performing step S312 as described herein). Steps S300 and S304 to S312 can be repeated for any number of composite parts to be manufactured - i.e. where steps S304 to S312 are all performed whilst the temperature of the body 212 is maintained within the temperature range (as described herein) for consolidating the composite part. As described herein, the relatively long periods of time required for the temperature within a typical autoclave chamber to be increased before consolidating a composite part, and subsequently decreased after consolidating that composite part, act as a bottleneck for typical autoclaving methods for manufacturing a composite part -limiting their throughput (e.g. number of composite parts that can be manufactured within a given period of time). This repetitive “thermal cycling” of a typical autoclave chamber is also highly energy intensive - increasing the monetary and environmental costs associated with typical autoclaving methods. By contrast, in a method of manufacturing a composite part according to the principles described herein, the temperature of the body 212 is maintained substantially constant throughout the placing, consolidating and removing steps described herein. This eliminates the relatively long periods of time associated with heating and cooling in typical autoclaving methods, as described herein. This increases the throughput (e.g. number of composite parts that can be manufactured within a given period of time) of a method according to the principles described herein, relative to a typical autoclaving method. Eliminating the repetitive “thermal cycling” when manufacturing a plurality of composite parts in series also reduces the energy requirements - and thereby monetary and environmental costs - associated with a method according to the principles described herein, relative to typical autoclaving methods. The method of manufacturing a composite part according to the principles described herein can be used to manufacture composite parts for use in automotive or aerospace applications, such as automotive bodywork parts or aircraft fuselage panels. In particular, the method of manufacturing a composite part according to the principles described herein is particularly suitable for manufacturing relatively high numbers of relatively small composite parts (e.g. air brakes). For example, the method according to the principles described herein may be particularly suitable for manufacturing composite parts having dimensions of approximately 50-2000mm by 50-2000mm by 50-2000mm. The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the invention.

Claims

1. A method of manufacturing a composite part, the method comprising:providing a composite consolidating apparatus, the composite consolidating apparatus comprising a chamber and a heatable body that at least partially surrounds the chamber; andwhilst the temperature of the body is maintained within a temperature range for consolidating the composite part:placing the composite part in the chamber;consolidating the composite part, wherein consolidating the composite part comprises transferring heat from the body to the composite part; andremoving the composite part from the chamber.

2. The method of claim 1, the method further comprising increasing the temperature of the body to within the temperature range for consolidating the composite part before placing the composite part in the chamber.

3. The method of claim 1 or 2, the method further comprising maintaining the temperature of the body within the temperature range for consolidating the composite part after the composite part has been removed from the chamber.

4. The method of any of claims 1 to 3, wherein consolidating the composite part comprises curing a matrix material comprised by the composite part.

5. The method of any preceding claim, wherein consolidating the composite part comprises causing the composite part to conform to a contoured forming surface of a mould.

6. The method of claim 5, wherein placing the composite part in the chamber comprises placing the composite part and the mould in the chamber.

7. The method of claim 6, wherein the composite part and the mould are placed in the chamber such that:the mould is in contact with the body; orthe mould is in contact with one or more spacer elements, the one or more spacer elements being in contact with the body.

8. The method of claim 7, wherein the one or more spacer elements comprise at least one spacer element having a contoured surface that corresponds to a non-forming surface of the mould.

9. The method of claim 7 or 8, wherein the one or more spacer elements comprise at least one spacer element having a contoured surface that corresponds to a surface of the composite part.

10. The method of any of claims 7 to 9, the method further comprising adjusting the size of at least one of the one or more spacer elements in order to adjust the spatial relationship between the composite part and the body.

11. The method of any of claims 7 to 10, wherein placing the composite part in the chamber comprises placing the composite part, the mould and the one or more spacer elements in the chamber12. The method of any of claims 7 to 11, the method further comprising selecting the one or more spacer elements from a plurality of spacer elements, the one or more spacer elements being selected in dependence on their size and / or thermal conductivity.

13. The method of any preceding claim, wherein consolidating the composite part comprises transferring heat from the body to the composite part by conduction.

14. The method of claim 13, when dependent on claim 5, wherein consolidating the composite part comprises transferring heat from the body, via the mould, to the composite part by conduction.

15. The method of claim 13 or 14, when dependent on claim 7, wherein consolidating the composite part comprises transferring heat from the body, via the one or more spacer elements and the mould, to the composite part by conduction.

16. The method of any preceding claim, wherein consolidating the composite part comprises transferring heat from the body to the composite part by radiation.

17. The method of any preceding claim, wherein the temperature of the body remains substantially constant throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber.

18. The method of any preceding claim, wherein the temperature of the body varies by less than 20°C throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber.

19. The method of any preceding claim, wherein the method does not comprise decreasing the temperature of the body between consolidating the composite part and removing the composite part from the chamber.

20. The method of any preceding claim, wherein the composite part comprises a reinforcing material impregnated with a matrix material.

21. The method of any preceding claim, the method further comprising: placing the composite part in the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part;increasing the pressure within the chamber to within a pressure range for consolidating the composite part;consolidating the composite part whilst the pressure within the chamber is maintained within the pressure range for consolidating the composite part;decreasing the pressure within the chamber to below the pressure range for consolidating the composite part; andremoving the composite part from the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part.

22. The method of any preceding claim, the method further comprising, after the composite part has been removed from the chamber:whilst the temperature of the body is maintained within the temperature range for consolidating the composite part:placing a further composite part in the chamber;consolidating the further composite part; andremoving the further composite part from the chamber.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:CLAIMS1. A method of manufacturing a composite part, the method comprising:providing a composite consolidating apparatus, the composite consolidating apparatus comprising a chamber and a heatable body that at least partially surrounds the chamber; andwhilst the temperature of the body is maintained within a temperature range for consolidating the composite part:placing the composite part in the chamber;consolidating the composite part, wherein consolidating the composite part comprises transferring heat from the body to the composite part; andremoving the composite part from the chamber.LDCM2. The method of claim 1, the method further comprising increasing the temperature of the body to within the temperature range for consolidating the composite part before placing the composite part in the chamber.

3. The method of claim 1 or 2, the method further comprising maintaining the temperature of the body within the temperature range for consolidating the composite part after the composite part has been removed from the chamber.

4. The method of any of claims 1 to 3, wherein consolidating the composite part comprises curing a matrix material comprised by the composite part.

5. The method of any preceding claim, wherein consolidating the composite part comprises causing the composite part to conform to a contoured forming surface of a mould.

6. The method of claim 5, wherein placing the composite part in the chamber comprises placing the composite part and the mould in the chamber.

7. The method of claim 6, wherein the composite part and the mould are placed in the chamber such that:the mould is in contact with the body; or16 07 25the mould is in contact with one or more spacer elements, the one or more spacer elements being in contact with the body.

8. The method of claim 7, wherein the one or more spacer elements comprise at least one spacer element having a contoured surface that corresponds to a non-forming surface of the mould.

9. The method of claim 7 or 8, wherein the one or more spacer elements comprise at least one spacer element having a contoured surface that corresponds to a surface of the composite part.

10. The method of any of claims 7 to 9, the method further comprising adjusting the size of at least one of the one or more spacer elements in order to adjust the spatial relationship between the composite part and the body.

11. The method of any of claims 7 to 10, wherein placing the composite part in the chamber comprises placing the composite part, the mould and the one or more spacer elements in the chamber12. The method of any of claims 7 to 11, the method further comprising selecting the one or more spacer elements from a plurality of spacer elements, the one or more spacer elements being selected in dependence on their size and / or thermal conductivity.

13. The method of any preceding claim, wherein consolidating the composite part comprises transferring heat from the body to the composite part by conduction.

14. The method of claim 13, when dependent on claim 5, wherein consolidating the composite part comprises transferring heat from the body, via the mould, to the composite part by conduction.

15. The method of claim 13 or 14, when dependent on claim 7, wherein consolidating the composite part comprises transferring heat from the body, via the one or more spacer elements and the mould, to the composite part by conduction.16 07 2516. The method of any preceding claim, wherein consolidating the composite part comprises transferring heat from the body to the composite part by radiation.

17. The method of any preceding claim, wherein the temperature of the body remains substantially constant throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber.

18. The method of any preceding claim, wherein the temperature of the body varies by less than 20°C throughout placing the composite part in the chamber, consolidating the composite part and removing the composite part from the chamber.

19. The method of any preceding claim, wherein the method does not comprise decreasing the temperature of the body between consolidating the composite part and removing the composite part from the chamber.

20. The method of any preceding claim, wherein the composite part comprises a reinforcing material impregnated with a matrix material.

21. The method of any preceding claim, the method further comprising:placing the composite part in the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part;increasing the pressure within the chamber to within a pressure range for consolidating the composite part;consolidating the composite part whilst the pressure within the chamber is maintained within the pressure range for consolidating the composite part;decreasing the pressure within the chamber to below the pressure range for consolidating the composite part; andremoving the composite part from the chamber whilst the pressure within the chamber is below a pressure range for consolidating the composite part.

22. The method of any preceding claim, the method further comprising, after the composite part has been removed from the chamber:whilst the temperature of the body is maintained within the temperature range for consolidating the composite part:placing a further composite part in the chamber;consolidating the further composite part; andremoving the further composite part from the chamber.

23. The method of any preceding claim, wherein the composite part is an automotive bodywork part.

24. The method of any preceding claim, wherein the composite part comprises reinforcing fibres impregnated with a resin.16 07 25Application No: GB2409904.6Examiner:Mr Darren WilliamsClaims searched: 1-22Date of search: 19 December 2024Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-22 US2010 / 221373 Al (CHEN) see especially paragraphs 0074-0075 X 1-22 US5731015 A (BARTILUCCI) whole document relevant X 1-7, 13, 14, 16-22 WO03 / 024686 Al (CONTARINO) whole document relevant v A 1-7, 13, 14, 16-22 US5747179A (MAT SEN) see especially figure 2 X 1-7, 13, 14, 16-22 JP2013154624 A (YOSHIHARA) see especially figure 5 v A 1-7, 13, 14, 16-22 JP2016144892 A (TANAKA) see especially figure 1 X 1 at least WO2011 / 136097 Al (HAJIKANO) see especially figure 1 X 1 at least JP2012025126 A (HISATOMI) see especially figure 1X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of same category. before the filing date of this invention. & Member of the same patent family Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:Search of GB. EP, WO &US patent documents classified in the following areas of the UKCX :Worldwide search of patent documents classified in the following areas of the IPC____________ B29C_____________________________________________________ The following online and other databases have been used in the preparation of this search report SEARCH-PATENTInternational Classification:Subclass Subgroup Valid From B29C 0033 / 02 01 / 01 / 2006 B29C 0035 / 02 01 / 01 / 2006 B29C 0043 / 52 01 / 01 / 2006

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