GB2602292A

GB2602292A - Heated tooling

Info

Publication number: GB2602292A
Application number: GB2020383.2A
Authority: GB
Inventors: Fishpool David; Van Gelder Richard
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2020-12-22
Filing date: 2020-12-22
Publication date: 2022-06-29
Also published as: GB202020383D0

Abstract

Tooling for forming a composite object 26 (such as for an aircraft), the tooling having an object side 32, which contacts the object, a substrate 12 providing the shape; a non-woven Carbon Nanotube (CNT) mat 14 bonded to the substrate; an electrically insulating layer 20 bonded to the non-woven CNT mat, first and second electrical contacts 18 define a heating area on the non-woven CNT mat and supply electrical power to the heating area, an electrical power supply is connected to the first and second electrical contacts, the temperature of the heating area is increased for heating the object. A layer of thermally conductive material 22, such a tinned steel may spread heat. A bead of conductive epoxy 16 may be provide electrical continuity between the electrical contacts and the non-woven CNT mat. A vacuum bag may be provided. Methods of constructing such tooling are described and their use in making a preform or cured composite object by draping fabric, either with a binder or pre-impregnated are described.

Description

HEATED TOOLING

TECHNICAL FIELD

[0001] The present invention relates to heated tooling for composite parts and methods of making the heated tooling.

BACKGROUND

[0002] There is a constant. drive in aviation to improve the efficiency of aircraft.. One way to improve efficiency is to reduce the weight of the aircraft. By substituting composite parts for metal parts, significant weight savings can be realised. Composite parts are made using a combination of reinforcement and matrix, most commonly in aerospace being carbon fibre reinforcement and a resin matrix.

[00O] When making composite parts for many applications, it is commonplace to drape the reinforcement component, in the form of fabric, onto tooling which is shaped to form the fabric into the appropriate shape of the part to be made. Since multiple layers of fabric may be used, the draped fabric may be somewhat bulky and the resulting form is fragile and will quickly become misshapen if removed from the tooling.

[0004] In order to provide the form with more resilience sheets of reinforcement fabric may be provided with a binder, for example a thin veil of thermoplastic stitched to the fabric. By applying heat and pressure, via an oven and vacuum bag, the form can be debulked and the binder activated to adhere the sheets of fabric together. This results in a more resilient preform which is suitable for further processing before the introduction of resin to form the composite part.

I00051 Since composite parts used in aircraft can be quite large, for example parts of the wings, the provision of an appropriately large oven can become challenging. Accordingly, an alternative to using an oven is to heat the tooling directly to activate the binder. Tooling can be heated, for example, by passing heated fluid through channels in the tooling or by resistively heating the tooling via embedded wires. However making tooling that is amenable to heating can be an expensive and time consuming process.

[0006] It would be desirable to provide a way to make heated tooling for shaping a composite part that is easier or less expensive to make, or at least provide an alternative way to make such heated tooling.

SUMMARY

[0007] A first aspect of the present invention provides tooling for forming a composite object, the tooling having an object side being the side of the tooling which contacts the composite object, the tooling further comprising: a substrate providing the shape of the tooling; a non-woven Carbon Nanotube (CNT) mat bonded to the substrate; an electrically insulating layer bonded to the non-woven CNT mat, the electrically insulating layer providing the object side of the tooling; and first and second electrical contacts, disposed apart front each other to define a heating area on the non-woven CNT mat and in electrical continuity with the non-woven CNT mat for supplying electrical power to the heating area such that in use, with an object to be formed on the object side of the tooling, when an electrical power supply is connected to the first and second electrical contacts, the temperature of the heating area is increased for heating the object..

[0008] Such tooling can be used to form a composite object by shaping and heating components of the object in a variety of ways. It can be used to activate a binder present in one or more layers of reinforcement fabric draped over the mould so as to create a preform, optionally in the presence of a compressive force such as that provided by a vacuum hag to bebulk the fabric. Alternatively or in addition, it can be used to cure a resin pre-impregnated into a fabric or infused into the fabric so as to create a composite object.

[0009] Preferably, the tooling further comprises a layer of thermally conductive material bonded to the electrically insulating layer, the layer of thermally conductive material providing the object side of the tooling. This helps to even out the heat created by passing electrical power through the non-woven CNT mat to improve the activation or curing effect of the tooling.

[0010] Optionally, the thermally conductive material comprises a sheet of tinned steel.

This was found to be an appropriate material in testing.

[0011] Preferably, the electrical continuity between the electrical contacts and the non-woven CNT mat is provided by a bead of conductive epoxy. Silver conductive epoxy was found to provide a very low resistance between the electrical contacts and non-woven CNT mat.

[0012] Optionally, the electrical continuity between the electrical contacts and the non-woven CNT mat is provided by a layer of conductive film adhesive. This may provide relatively high performance with simple installation.

[0013] Optionally, the first and second contacts are disposed between the electrically insulating layer and the non-woven CNT mat_ and the tooling further comprises first and second terminals electrically connected to the first and second contacts for connecting a power supply to the first and second electrical contacts.. This provides a simple and reliable way to provide power to the non-woven CNT mat.

[0014] Preferably, the tooling further comprises a vacuum bag interface for coupling to a vacuum bag around the heating area of the non-woven CNT mat. This provides a simple way to secure a vacuum bag to the tooling for providing a compressive force when debulking or curing fabric on the tooling.

[0015] A second aspect of the present invention provides a method of making tooling for forming a composite object, comprising: providing a mould having the shape that the composite object is intended to have; placing an electrically insulating layer onto the mould; placing first. and second electrical contacts on the mould; providing an electrical continuity component for each of the first and second electrical contacts; placing a non-woven CNT mat onto the electrically insulating layer and each of the first and second electrical contacts such that each electrical contact is disposed apart from cach other on the non-woven CNT mat; placing a substrate onto the mould on top of the non-woven CNT mat; providing resin to the contents of the mould; and curing the resin such that the components of the tooling are bonded together by the resin to create the tool.

I00161 Accordingly the tooling can be made as a direct complement to the desired shape and can even be formed using a previously-manufactured example of the composite object the tooling is to be used with.

[00171 A third aspect of the present invention provides a method of making tooling for forming a composite object, comprising: providing a mould for shaping the tooling; placing a substrate onto the mould; placing a non-woven CNT mat onto the substrate; placing first and second electrical contacts on the non-woven CNT mat such that each electrical contact is disposed apart from each other on the non-woven CNT mat; providing an electrical continuity component For each of the first and second electrical contacts; placing an electrically insulating layer onto the non-woven CNT mat; providing resin to the contents of the mould; and curing the resin such that the components of the tooling are bonded together by the resin to create the tool.

I00181 In either the second or third aspect the method may further comprise providing a layer of thermally conductive material on the electrically insulating layer. This material can help evenly spread the heat produced by the eventual tooling and by including it in the manufacture of the tooling it can be co-cured with the tooling forming a resilient bond.

[00191 Preferably, the thermally conductive material comprises a sheet of tinned steel which was found to be an effective heat spreader.

I00201 Optionally, the step of providing resin to the contents of the mould is carried out by using fabric pre-impregnated with a resin. Such pre-impregnated fabric is often easier to use than dry fabric which is then infused with resin.

[0021] A fourth aspect of thc invention provides a method for making a preform for making a composite object by activating a binder attached to or embedded in a reinforcement Fabric to stabilise the preform, the method comprising: providing tooling according to the first aspect, draping fabric comprising a hinder over the object side of the tooling; supplying electrical power to the first and second electrical contacts to heat the fabric to an activation temperature of the binder; and allowing the fabric to cool, thereby setting the binder to create the preform from the fabric.

[0022] Simply activating the binder in this way may be sufficient to make a preform, but this could be combined with a vacuum bag step to debulk the fabric in the case of multiple layers being used.

[0023] A fifth aspect of the invention provides a method for making a composite object by curing a resin pre-impregnated into a fabric, the method comprising: providing tooling according to the lirst aspect, draping fabric pre-impregnated with resin over the object side or the tooling; coupling a vacuum hag to the tooling over the fabric and around the heating area; connecting the vacuum bag to a vacuum source; and supplying electrical power to the first and second electrical contacts to heat the fabric to the cure temperature of the resin, thereby curing the resin to create the composite object.

[0024] A sixth aspect of the invention provides a method for making a composite object.

by infusing resin into a dry fabric as loose fabric or a preform, the method comprising: providing tooling according to the first aspect, draping dry fabric over the object side of the tooling; coupling a vacuum bag to the tooling over the fabric and around the heating area; connecting the vacuum bag to a vacuum source; supplying liquid resin to the fabric within the vacuum bag; and supplying electrical power to the first and second electrical contacts to heat the fabric to the cure temperature of the resin, thereby curing the resin to create the composite object.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Embodiments of the invention will now he described, by way of example only, with reference to the accompanying drawings, in which: [0026] Figure 1 is a perspective view of an aircraft; [0027] Figure 2 is a schematic cross section view of a flat piece of heated tooling with an object to be formed placed upon it; and [0028] Figure 3 is a schematic plan view of the flat piece of heated tooling of Figure 2.

DETAILED DESCRIPTION

[0029] Referring now to Figure 1, a conventional aircraft 1 is shown. The aircraft 1 comprises a fuselage 2, wings 3, an empennage 4, landing gear 5 with its associated landing gear bay doors 6 and engine nacelles 7. Conventionally, all or most of the structure of such an aircraft, from the structural members such as wing spars and ribs through to aerodynamic surfaces such as wing skins and control surfaces, would be made of metal. By substituting composite objects for metal parts substantial weight savings can be achieved.

[0030] Aerodynamic surfaces of the aircraft. are particularly suitable for replacement by composite objects due to the relatively low stresses they are exposed to. Examples include the skin of fuselage 2; the covers, leading edge and trailing edge of wings 3 and empennage 4; and the landing gear bay doors 6. Control surfaces associated with the wings 3 and empennage 4 may also be made using composite objects. These components tend to be curved and so tooling that can impart the curve are required if they are to be made using composite objects.

[0031] Structural components of the aircraft, such as the frames and stringers that reinforce the fuselage 2 or the spars and iibs of the wings 3 and empennage 4 may also be made using composite objects. Thc high loading that may be placed on these objects means that the fibre reinforcements should be carefully aligned to ensure that their anisotropic strengths are appropriately aligned for the forces the part will encounter. These objects often have pronounced features such as sharp bends or curves in order to provide appropriate strength, and so again tooling that can impart that curvature is required.

[0032] The size of aircraft components is very much larger than those traditionally formed using composite materials. The wing cover of large passenger aircraft, for example, can be tens of metres long. Accordingly an appropriately sized oven can be expensive in terms of space and/or cost, so providing local heating to the composite parts is desirable.

[0033] Embodiments of the present disclosure provide a new type of heated tooling, particularly suitable for forming the curved composite objects required in aircraft manufacture. The tooling is resistively heated by passing an electrical current through a nonwoven mat of carbon nanotubes (CNT) that comprises a multitude of tortuous discrete long CNT fibres. Such non-woven CNT mats are highly flexible and electrically conductive. Use of such a non-woven CNT mat as the heating clement in tooling permits simple and efficient assembly of the tooling since a sufficiently large non-woven CNT mat can be draped according to the desired shape of the tooling.

[0034] Figures 2 and 3 show schematics of a tooling according to an embodiment of the disclosure. Figure 2 shows a schematic cross section view of an exemplary piece of tooling 10 for forming a composite object. For simplicity the tooling 10 is shown as being flat but in practice could be any shape as necessary. On the non-object side 32 of the tooling there is a bottom layer of substrate 12 which in this embodiment is Glass Fibre Reinforced Plastic (GFRP). Substrate 12 provides the necessary structure and rigidity to the tooling such that it does not deform in use. A single, continuous non-woven CNT mat 14 is provided on top of the substrate 12. The non-woven CNT mat 14 is directly adjacent to the substrate 12 and is bonded to it, in this example by means of the same resin which binds the Glass Fibres together in the substrate 122. The non-woven CNT mat 14 forms the middle layer of the tooling.

[0035] Two contacts 18 are in electrical continuity with the non-woven CNT mat 14 for passing electricity through the mat 14 in order to heat the tooling 10. These contacts 18 are made of Nickel and are arranged apart from each other, in this embodiment on opposite edges of the non-woven CNT mat 14 as can he seen from Figure 3. To provide good electrical continuity between the contacts 18 and the non-woven CNT mat 14, the contacts 18 are attached to the non-woven CNT mat 14 in this embodiment by a bead or layer of silver conductive epoxy 16.

[0036] When an electrical power supply is connected to the contacts 18, the arca between them will increase in temperature due to resistive heating. Accordingly, the contacts 18 define a heating area 34 which is the part of the tooling which will increase in temperature most readily and the part that will reach the highest temperature.

[0037] Figure 2 shows an object, 26, that is to be formed with the tooling 10. The object side 28 of the tooling makes contact with the object in use. The tooling 10 further comprises an electrically insulating layer 20 for preventing electrical contact between the non-woven CNT mat 14 and the object 26 to be formed on the tooling 10. The electrically insulating layer 20 is directly adjacent the non-woven CNT mat 14 and bonded to it. In this embodiment, the electrically insulating layer 20 comprises a single layer of GFRP bonded to the mat 14 by its resin. It is desirable for the electrically insulating layer to be thin and thermally conductive for conducting heat from the non-woven CNT mat 14 to the object 26. Accordingly the electrically insulating layer 20 is in good thermal contact with the non-woven CNT mat 14.

[0038] In this embodiment, the electrically insulating layer 20 covers the contacts 18 and extends to the edge of the tooling 10. Electrical terminals 24 (shown in Figure 3) in electrical communication with the contacts 18 are provided that extend past the top layer 20 so that power can be provided to the contacts 18 by connecting a power supply to the terminals 24.

[0039] In the embodiment of Figure 2, the tooling 10 is further provided with a heat spreader 22 being a layer of thermally conductive material directly adjacent to and bonded to the electrically insulating layer. The heat spreader 22 provides the object side 28 of the tooling. The heat spreader evens out the heat provided by the non-woven CNT mat 14, mitigating any hot or cold spots that may form as it is resistively heated. The heat spreader 22 is in good thermal contact with the electrically insulating layer 20, and through that the non-woven CNT mat 14 for conducting heat to the object 26 in use.

[0040] The heat spreader 22 could comprise that a simple layer of metal, such as aluminium foil. Preferably, the heat spreader 22 comprises a tinned steel sheet. Since the heat spreader 22 is not in electrical contact with the non-woven CNT mat 14 or contacts 18 due to the electrically insulating layer 20 it does not need to be electrically isolated from the object to be formed on the tooling.

[0041] In some embodiments, the heat spreader 22 could be omitted and then the insulating layer 20 will provide the object side 28 of the tooling 10. Such tooling 10 without a heat spreader 22 may be suitable for use where longer heating times are to be used, such that any part of the object 26 over a cold spot in the heating area 34 will still be appropriately warmed by conduction within the tooling 10 or object 26.

[0042] Figure 3 shows a plan view of the tooling 10 of Figure 2. It can be seen in Figure 3 that the non-woven CNT mat 14 need not extend to the edge of the tooling 10. Since the heating area 34 is an area of the non-woven CNT mat 14 defined by the contacts 18, the mat 14 will extend past the heating area 34 to at least provide a space for interfacing with the contacts 18. The mat 14 may extend beyond the contacts 18 and/or the heating area 34 in some embodiments. The heat spreader 22 preferably covers at least those areas of tooling 10 where an even distribution of heat is most important, which may be all or a portion of heating area 34.

[0043] Around the periphery of tooling 10 there is provided a vacuum bag interface, 30. In this embodiment, this is simply an area of tooling outside the heating area 34 to which a vacuum bag may be adhered by adhesive.

[0044] Since the tooling 10 in the embodiments of Figures 2 and 3 is made using GFRP and a flexible non-woven CNT mat, it can be constructed quickly and easily by laying up layers of pre-impregnated glass fibre fabric, the non-woven CNT mat and electrical contacts before co-curing them together. This can be done using a mould to impart the correct shape to the tooling. This mould could he quickly and easily made using additive manufacturing to provide a very quick turnaround. Accordingly, heated tooling can be quickly and easily made for any shape desired.

[0045] In one embodiment, this tooling 10 can be made using a mould which is in the shape that the composite object (to be formed using this tooling) is intended to have, which could even be an example of such an object or a mock-up of the object made from a different material. Accordingly the mould contacts the tooling on the object side 28 of the tooling, which is the side that makes contact with the object in use. In this case the tooling 10 can be made by first placing a layer of fabric that will become the electrically insulating layer 20 onto the mould, followed by the electrical contacts 18 onto the electrically insulating layer 20. A bead of silver conductive epoxy 16 can then be placed on each electrical contact 18 to act as an electrical continuity component for each of electrical contacts 18. The non-woven CNT mat 14 can then be placed on top of the electrically insulating layer of fabric 20 and each of the electrical contacts 18 such that each electrical contact 18 is disposed apart from each other or on opposite edges of the non-woven CNT mat 14 to define a heating area 34.

[0046] Finally, the bottom layer of fabric for forming the substrate 12 can be placed onto the mould on top of the non-woven CNT mat 14. Whilst normally a single sheet of pre-impregnated glass fibre fabric will be used to form the electrically insulating layer 20 so as to minimise the material between the non-woven CNT mat 14 and the object, several layers of this fabric can he used to form the substrate to provide sufficient rigidity to the tooling 10. Since the material used to form the top and bottom layers 20, 12 is pre-impregnated with resin the whole assembly can then simply be cured to provide the tooling 10 appropriate for forming the object.

In another embodiment, the tooling 10 is made using a mould that contacts the non-object side 32 of the tooling. In this case the tooling 10 can he made hy first placing a bottom layer of fabric for forming the substrate 12 onto the mould. This is followed by the non-woven CNT mat 14 which is placed onto the bottom layer. Beads of silver conductive epoxy 16 can then be placed on the non-woven CNT mat 14 to provide an electrical continuity component for each of the electrical contacts 18, which are placed on top of the silver conductive epoxy 16. As before, the electrical contacts are placed to define a heating area 34 on the non-woven CNT mat 14. Finally, the electrically insulating layer of fabric 20 can he placed onto the nonwoven CNT mat 14 and electrical contacts 18, before curing the assembly to provide the tooling 10.

[00471 Although in both cases above the electrically insulating layer 20 has been described as being made using a sheet of pre-impregnated glass fibre fabric, in some embodiments the electrically insulating layer 20 could be made using only resin with no reinforcement, hi such embodiments extra resin could be provided to the object side of the non-woven CNT mat 14, or sufficient resin may be present in the mould to seep through the non-woven CNT mat 14 such that it is covered in electrically insulating resin.

[00481 The heat spreader 22 can be adhered to the tooling 10 once it has been cured.

Alternatively, the heat spreader can be included with die other components, on top of the electrically insulating layer of fabric, when making the tooling. The resin that binds the tooling together will then also bond the heat spreader 22 to the tooling 10.

[00491 In use as a forming tool, the heated tooling 10 is used to shape layers of reinforcement fabric (that will make the eventual composite object 26) into a preform. This is done using a binder which adheres the layers of fabric together, such as a veil of thermoplastic that is stitched to each layer of fabiic. After the layers of fabiic are draped across the tooling 10, a vacuum bag is connected to the vacuum bag interface 30 and an electrical power supply is connected to the terminals 24. The tooling 10 is resistively heated to activate the binder in the fabric whilst the vacuum bag is used to compress (or debulk) the fabric so as to form a preform, which can be removed from the tooling for further processing once cool. Alternatively the preform could be left in place on the tooling for further processing.

[00501 In addition to being useful as a forming tool, the heated tooling 10 can also be used as a curing tool. Curing of a composite object is performed once a resin has been introduced, and normally involves higher temperatures than making a preform. The heated tooling 10 would therefore be supplied with a higher electrical power to increase the temperature reached but would not require any further modifications to act in this way. The tooling could serve as a base for fabric pre-impregnated with resin or for resin infusion of dry fabric which may have been debulked and preformed as described above using the tooling.

[0051] A number of alternatives have been considered for use in making or using the tooling desciibed herein. Electrical continuity between the contacts 18 and non-woven CNT mat 14 can be provided using silver conductive epoxy as an electrical continuity component 16. Other options include silver paint, sputter coated gold, or a layer of conductive adhesive film, which has the benefit of being particularly easy to use.

[0052] Although the substrate 12 and electrically insulating layer 20 have been described as being formed of GFRP, many alternative materials are possible. These could be flexible fabrics such as woven carbon fibre for use in making the tooling as a composite assembly itself, or particularly in the case of the substrate 12 any other appropriate material for supporting the structure such as solid plastics, metal, wood, glass etc. Depending on the material chosen other methods for assembling the tooling 10 may be required, for example a resin infusion step may be used if dry (i.e. non pre-impregnated) fabric is used to construct the tooling. The electrically insulating layer 20 could comprise a thin layer of plastic or resin alone to provide the electrical isolation function.

[0053] The contacts 18 have been described as being formed of Nickel, which was found to provide the best performance. Of course, other metals could be used to provide the contacts. Copper in particular provides good conductivity but generally has lower performance than Nickel in terms of adhesion and temperature performance. . [0054] The size of the contacts will depend on the temperature the tooling 10 is required to reach, since higher target temperatures will generally require a higher electrical power which may require larger contacts 18. For example, a sample of non-woven CNT mat 14 150mm x 240mm in size was heated to 70 degrees Celsius using contacts approximately 30mm wide on each of the short sides of the non-woven CNT mat 14 and applying electficity across them at 8.8 V and 15 A. Higher temperatures are achievable with additional power, with for example 130 degrees Celsius being achieved in one test by applying electricity at 12V and 30A. DC power was used in testing for simplicity but AC power is expected to be suitable as well.

[0055] The terminals 24 could be provided in a variety of different ways. For testing purposes, the tooling was drilled through at each contact 18 and a metal bolt passed through the resulting hole to act as a terminal. If the terminals 24 are to be provided at an edge of the tooling 10, then wires could be included in the tooling as it is made to connect the terminals 24 to the contacts 18. It would be desirable to combine the terminals 24 in an embedded connector to make connecting a power supply simpler and safer.

[0056] Although the method of constructing the tooling has been described using pre-impregnated glass fibre fabric sheet., the skilled person will realise many alternatives are possible. For example, the tooling could be constructed using a dry fibre fabric and subsequent resin infusion step before curing.

[0057] Although the invention has been described above with reference to one or more preferred examples or embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

[0058] Where the term -or" has been used in the preceding description, this term should be understood to mean -and/or", except where explicitly stated otherwise.

Claims

CLAIMS: 1. Tooling for forming a composite object, the tooling having an object side being the side of the tooling which contacts the composite object, the tooling further comprising: a substrate providing the shape of the tooling; a non-woven Carbon Nanotube (CNT) mat bonded to the substrate; an electrically insulating layer bonded to the non-woven CNT mat, the electrically insulating layer providing the object side of the tooling; and first and second electrical contacts, disposed apart from each other to define a heating area on the non-woven CNT mat and in electrical continuity with the non-woven CNT mat for supplying electrical power to the heating area such that in use, with an object to be formed on the object side of the tooling, when an electrical power supply is connected to the first and second electrical contacts, the temperature of the heating area is increased for heating the object..
2. Tool ng according to claim 1, further comprising a layer of thermally conductive material bonded to the electrically insulating layer, the layer of thermally conductive material providing the object side of the tooling.
3. Tooling according to claim 2, wherein the thermally conductive material comprises a sheet of tinned steel.
4. Tooling according to claim 1.2 or 3, wherein the electrical continuity between the electrical contacts and the non-woven CNT mat is provided by a bead of conductive epoxy.
5. Tooling according to claim 1.2 or 3, wherein the electrical continuity between the electrical contacts and the non-woven CNT mat is provided by a layer of conductive film adhesive.
6. Tooling according to any preceding claim, wherein the first and second contacts are disposed between the electrically insulating layer and the non-woven CNT mat, further comprising first and second terminals electrically connected to the first and second contacts for connecting a power supply to the first and second electrical contacts.
7. Tooling according to any preceding claim, further comprising a vacuum bag interface for coupling to a vacuum bag around the heating area of the non-woven CNT mat.
8. A method of making tooling for forming a composite object, comprising: providing a mould having the shape that the composite object is intended to have; placing an electrically insulating layer onto the mould; placing first and second electrical contacts on the mould; providing an electrical continuity component for each of the first and second electrical contacts; placing a non-woven CNT mat onto the electrically insulating layer and each of the first and second electrical contacts such that each electrical contact is disposed apart from each other on the non-woven CNT mat; placing a substrate onto the mould on top of the non-woven CNT mat; providing resin to the contents of the mould; and curing the resin such that the components of the tooling are bonded together by the resin to create the tool.
9. A method of making tooling for forming a composite object, comprising: providing a mould for shaping the tooling; placing a substrate onto the mould; placing a non-woven CNT mat onto the substrate; placing first and second electrical contacts on the non-woven CNT mat such that each electrical contact is disposed apart from each other on the non-woven CNT mat; providing an electrical continuity component for each of the first and second electrical contacts; placing an electrically insulating layer onto the non-woven CNT; providing resin to the contents of the mould; and curing the resin such that the components of the tooling are bonded together by the resin to create the tool.
10. A method according to claim 8 or 9, further comprising providing a layer of thermally conductive material on the electrically insulating layer.
11. A method according to claim 10, wherein the thermally conductive material comprises a sheet of tinned steel.
12. A method according to any one of claims 8 to 11, wherein the step of providing resin to the contents of the mould is carried out by using fabric pre-impregnated with a resin as one or both of the electrically insulating layer and the substrate.
13. A method of making a preform for making a composite object by activating a binder attached to or embedded in a reinforcement, fabric to stabilise the preform, the method comprising: providing tooling according to any one of claims 1 to 7, draping fabric comprising a binder over the object side of the tooling; supplying electrical power to the first and second electrical contacts to heat the fabric to an activation temperature of the binder; and allowing the fabric to cool, thereby setting the binder to create the preform from the fabric.
14. A method for making a composite object by curing a resin pre-impregnated into a fabric, the method comprising: providing tooling according to any one of claims 1 to 7, draping fabric pre-impregnated with resin over the object side of the tooling; coupling a vacuum bag to the tooling over the fabric and around the heating area; connecting the vacuum bag to a vacuum source; and supplying electrical power to the first and second electrical contacts to heat the fabric to the cure temperature of the resin, thereby curing the resin to create the composite object.
15. A method for making a composite object by infusing a resin into a dry fabric as loose fabric or a preform, the method comprising: providing tooling according to any one of claims 1 to 7, draping dry fabric over the object side of the tooling; coupling a vacuum bag to the tooling over the fabric and around the heating area; connecting the vacuum bag to a vacuum source; supplying liquid resin to the fabric within the vacuum bag; and supplying electrical power to the First and second electrical contacts to heat the fabric to the cure temperature of the resin, thereby curing the resin to create the composite object.