GB2410920A

GB2410920A - A method of producing a mould

Info

Publication number: GB2410920A
Application number: GB0501336A
Authority: GB
Inventors: Simon James Jenner
Original assignee: FULL BAR COMPOSITE Ltd
Current assignee: FULL BAR COMPOSITE Ltd
Priority date: 2004-01-24
Filing date: 2005-01-24
Publication date: 2005-08-17
Anticipated expiration: 2025-01-24
Also published as: WO2005070641A1; GB0401542D0; GB2410920B; GB0501336D0

Abstract

A method of producing a mould 50 for a product, the method comprising the steps of providing a sheet 25 of material having first 30 and second 35 faces and forming the sheet 25 onto an open face primary mould former 10 having a shape corresponding to a required shape for the mould 50 with the first face 30 of the sheet 25 in contact with the former 10, wherein the second face 35 of the thus-formed sheet 25 is utilised to determine the shape of the subsequently moulded product. The sheet material 25 may comprise a thermoformable plastics material such as acrylonitrate-butadiene-styrene. The second face 35 of the sheet 25 may be coated with a metallic surface finish such as being plated with chrome.

Description

24 1 0920

A METHOD OF PRODUCING A MOULD

The present invention relates to a method of producing a mould. The present invention is particularly, although not exclusively, concerned with a method for production of multiple identical moulds suitable for moulding products from composite materials.

In the context of the present invention the term mould can apply to the situation in which the mould produced is a mould half to be used in conjunction with a 0 corresponding opposite gender mould half in a closed face arrangement, or where the mould is the entirety of the moulding apparatus in an open face ar angement.

It is known to form moulds suitable for moulding products from composite materials from a mould former, which is sometimes known as a plug. For example, a block of resin can be hand-shaped or computer-cut to form a mould former with a shape corresponding to a required mould shape. Thereafter material from which the mould is to be produced is formed onto the mould former. This is traditionally done by a process known as wet lay-up, in which uncured material (which may itself be a composite material) is applied to the moLrId former by hand and allowed to set.

This known method is time-consuming because it requires hand-lamination and it results in the mould former being occupied for signif cant periods of time whilst the mould material sets, which is a disadvantage particularly where multiple identical moulds are required. In addition, the surface of the mould in contact with the mould e. . . . * . . ..

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former becomes the moulding surface which subsequently receives the composite material to be moulded; so, for example, the mould former would be of a male configuration for producing a female mould. The surface of the mould former must therefore be extremely accurate if a product resulting from a mould so formed is to be of good quality. The more accurate the mould former must be, the more time and expense is usually required in its preparation and finishing, and even then there will usually be imperfections present.

According to the present invention there is provided a method of producing a mould for a product, the method comprising the steps of providing a sheet of material having first and second faces, and forming the sheet onto an open face primary mould former having a shape corresponding to a required shape for the mould with the first face of the sheet in contact with the former, wherein the second face ofthe thus- formed sheet is utilised to determine the shape of the subsequently moulded product.

The second face of the sheet is therefore the face which will subsequently receive and be in contact with the material from which the product is to be moulded. Conversely the first face of the sheet is the face which is not subsequently in contact with the material to be moulded in use of the mould. The face of the sheet material which is 2 0 remote from the mould former when the sheet is formed into a mould is therefore the face for receiving material to be moulded into a product.

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The method is possible because the material used to produce the mould is in sheet form. By using a method in which a laminar element in the form of a sheet is formed onto the mould former, the shape of the side of the sheet not directly in contact with the mould former can be dictated. This is particularly advantageous because it has been found that the quality of the face remote from the former is better for moulding.

By this it is meant that there are generally less imperfections in the face of the sheet not in contact with the former, which makes this face more preferable tor subsequent use as a surface to receive material to be moulded. This means that the surface finish of the mould former can be less precise, which alleviates the need for surface finishing such as sanding and filling.

The mould of the present invention is itself formed by moulding, and the product is subsequently moulded using the mould.

The sheet material is preferably thermoformable. By using thermoforming techniques the amount of time taken to apply the mould material onto the mould former and the amount of time for which the mould former is occupied can be greatly reduced.

Once the primary mould former has been constructed, multiple identical moulds can 2 0 be produced cheaply, quickly and easily because they are moulded from thermoformable material and not hand-laminated with uncured material.

: ë ' .,. . .: : .' .: , The mould material may comprise a thermoformable plastics material, for example acrylonitrate-butadiene-styrene (ABS). ABS is a suitable material to use for producing moulds because it is very tough.

The sheet material may comprise acrylic-capped ABS. This is a sheet of ABS with a thin film of acrylic bonded to one face. The acrylic film is preferably on the second lace of the material because it maintains an excellent surface finish after moulding and is therefore suited to receive material subsequent product for moulding. Other films, such as polyester or styrene film may also be used.

The choice of f lm may be dependent upon the material which will subsequently be in contact with the second face in moulding operations. The film must be compatible and preferably non-reactive with the product material, particularly if the product is to be removed from the mould after curing.

The plastics material preferably will have properties such as impact resistance, stiffness, resistance to shrinkage following moulding and temperature resistance to allow curing cycles in the mould if required.

2 0 The use of sheet material to form the mould reduces material usage when compared to a process in which uncured material is spread onto a mould former, and complete coverage of the mould former moulding surface is ensured.

:; .e' 2,,. .' : : a..e ' .: It has been found that the time taken from finalising a product design to completion of a mould for the product can be dramatically reduced and simplified when compared to existing processes.

The mould former must be suitably shaped in order to accommodate the difference in size of the mould compared to the mould former due to the thickness of the sheet.

Depending on the sheet material used for the mould and the requirements from the moulding process, subsequent processing may be required in order to make the sheet suitable for use as a mould.

The method of the present invention may further comprise the step of coating one or both of the first and second faces of the mould. The second face of the mould may be treated with a metallic surface finish, such as chrome-plating. Whilst the shape ofthe mould is dictated by the face of the sheet, a thin metallic surface finish can act to protect the sheet surface from the material to be moulded, allows the article produced in the mould to be removed easily following moulding, and acts as a skin to make the surface non-porous.

Once the mould is formed it may be ready immediately for use in moulding operations.

e a ë . If the sheet material is relatively thin then it may be too flexible after formation to function as a stand-alone moulding unit not requiring any support to maintain shape.

Accordingly some form of backing structure may be required.

However, some combinations oi the type of material and its thickness and to some extent the shape of the mould can result in sufficiently stiff moulds that they can function without the requirement for backing structures or other support. For example, a mould forming made from a sheet of acrylic capped ABS which is approximately 6mm thick has been found to result in a stiff mould which does not require any strengthening or support.

As discussed above, due to the use of sheets of material, following moulding of the mould on the primary mould fonder the sheet may still be flexible, even, for example, following a metallic surface finish coating. A coating may be applied to the sheet to stabilise the shape of the mould.

The stabilising coating may be a foamed compound, for example Froth-Pak (registered trade mark) which is produced by Eco Polyurethane Systems. The foamed compound may be fire-retardant and/or solvent free, which would be advantageous 2 0 particularly from a health and safety perspective.

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It may be preferable for a stabilising coating to be applied to the first face ofthe sheet, which is the face of the mould formed in contact with the mould former. The method may therefore further comprise the step of laying the sheet onto a secondary mould former which is oppositely shaped to the primary mould former, such that the first face is exposed thereby allowing it to be coated whilst supported in its required shape.

The primary mould former could be a female mould former and the secondary mould former would therefore be an oppositely shaped male mould former.

A thermoformable mould sheet may be formed onto the primary mould former by vacuum forming, which is a process in which the sheet is heated to a pliable state and then placed over the mould former and drawn onto the former to produce the desired shape. This requires vacuum holes to be formed in the mould former to allow a vacuum applied from beneath the mould former to draw the sheet down onto the mould former. Vacuum forming is a very cost effective and time-efficient method for producing moulded components. Importantly, in vacuum forming the integrity of the face of the sheet not in contact with the mould former is unaf'f'ected by the moulding operation, as the sheet is drawn down from below.

2 0 Alternatively, the sheet may be formed onto the mould former by press forming or other suitable forming methods. All that is required is that the sheet is made to conform to the mould former to produce a mould with the required shape.

. be. -: ë A: . . An open face mould produced according to the present invention can then itself be used as a mould for subsequent forming of components. For example, components could be vacuum formed from further thermoplastic sheets. This would require the mould material to have a higher temperature resistance than the material to be moulded.

In its simplest form the present invention provides for the production of one or more thermoplastic female open face moulds. However, the underlying principle of the present invention could equally well be applied to male moulds or closed face moulds.

In one embodiment of the present invention the method further comprises the steps of adding a blank to the second face of the formed sheet, the blank having the shape of a product to be subsequently moulded, and forming a backing mould onto the mould and the blank from a backing sheet having first and second backing faces, thereby producing a closed face mould for producing a product having the shape of the blank.

The mould and the backing mould therefore comprise the female and male mould halves of a closed face mould.

2 0 The backing mould is sequentially moulded over the mould with the blank in place so that the blank forms a cavity between the mould and the backing mould suitable for the subsequent introduction of material to form a product having the shape of the blank.

e e ë e e . . . . In addition to moulding the backing mould around an article blank, inserts could also be included for plants subsequently required in use of the backing mould. For example, a resin distribution gallery, impressions for seals or other rebates could be formed into the backing mould as it is t'ormed. This means that the plants do not have to be formed in the backing mould after moulding, which saves time.

Once formed the backing mould may undergo post-moulding processing as described above for the mould. So, for example, one or both of the first and second backing faces of the backing mould may be coated.

In this method the first backing Lace ofthe backing sheet is in contact with the mould and the blank. Subsequently the first backing face is also used as the product-defining surface. In addition the method may further comprise the step of laying the backing sheet onto a tertiary mould former oppositely shaped to the mould with the blank, with the second backing face in contact with the former, thereby allowing first backing face of the backing sheet previously in contact with the mould and the blank to be coated whilst supported in its required shape.

Of course the backing mould could be produced independently ofthc mould such that 2 0 the backing mould production process could be identical to the mould production process.

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The backing mould material may comprise a thermoformable material such as thermof'ormable plastics material, for example acrylonitrate-butadienestyrene (ABS).

The backing mould sheet material may be the same as or different to the mould sheet material.

The backing mould sheet may be formed onto the mould and the blank by vacuum forming. Alternatively the sheet may be formed onto the mould and the blank by press forming.

The present invention also provides a method of producing a mould for a product, the method comprising the steps of preparing an open face primary mould former having a shape corresponding to a required shape for the mould, providing a sheet of material having first and second faces, forming the sheet onto the primary mould former with the first face in contact with the former, and thereafter utilising the second face ofthe thus-formed sheet to determine the shape of the subsequently moulded product.

The present invention also provides a mould produced by the method as described above.

The present invention also provides a method of producing a composite material product mould, comprising the steps of providing a sheet of formable material and l'orming the sheet onto a primary mould former having a shape corresponding to a required shape for the mould.

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. The mould may be reusable. Accordingly, once the product has been formed it can be removed from the mould and another product can be formed.

Because the result of the method is a reusable mould it is easy to produce multiple moulds which can be used many times. Accordingly it would be easy to scale up production of a mowlded product.

Although the mould may be reusable it may have a finite lifespan as the product moulding steps would gradually damage the mould to the point at which it would need replacing. However re-tooling would be extremely simple because all that is required is for another mould to be moulded.

The mould may be adapted to receive composite material to form a product.

The method may further comprise the step of using the mould to form a product.

The present invention also provides a method of producing a moulded product comprising the steps of: providing a sheet of mould material having first and second faces and forming the sheet onto a primary mould former with the first face of the 2 0 sheet in contact with the former; removing the thus-formed mould from the primary mould former; and using the second face of the sheet to receive material to be moulded into a product.

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e A. . Having resulted in the formation of a product the method may further comprise the step of removing a formed product from the mould.

The present invention also provides a method of producing a reusable mould comprising the steps of: providing a sheet of mould material having first and second faces; and forming the sheet of mould material having first and second faces; and forming the sheet onto an open face primary mould former having a shape corresponding to a required shape for the mould with the first face in contact with the former; in which the second face ofthe thus-formed mould is utilised to determine the 0 shape of subsequently moulded products.

The present invention also provides a mould produced by a method as described herein.

The present invention also provides a product formed by a mould produced by a method as described herein.

The present invention could be considered as a method of product manufacture comprising the steps of forming a mould and using it to form a product.

The present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: .e..

- e ee e ë ee . . see e.e - Figures I a to 1 g are a series of diagrammatic representations illustrating the steps in producing a female open face mould according to a first embodiment of the present invention; Figures 2a to 2e are a series of diagrammatic representations illustrating the steps in producing a closed face mould according to an alternative embodiment ofthe present invention; and Figures 3a to 3i are a series of diagrammatic representations illustrating the steps in a method of mould and product formation according to an alternative embodiment.

Referring first to Figure la there is shown a primary mould former 10. The primary mould former 10 is shaped from a resin block to include a moulding surface 15 with a shape corresponding to a required shape for a mould. In this embodiment a vacuum forming technique is employed and therefore vacuum posts 20 are machined into the primary mould former 10, as shown in Figure lb. Referring now to Figure 1 c a sheet 25 of thermoformable plastics material is provided.

The sheet 10 is heated to a pliable state and then a vacuum is produced beneath the 2 0 primary mould former 10 through the vacuum port 20. The sheet 25 is then drawn onto the primary mould former surface 15, as shown in Figure 1 d.

ace a.e a a eee a ë a a a ma, asa The primary mould former 10 is itself a female mould, and the sheet 25 is laminar, having substantially parallel first and second faces 30,35. Therefore, whilst the first face 30 is directly in contact with the moulding surface 15 of the primary mould former 10 the second face 35 is formed to have a parallel and corresponding shape to the mould surface 15. This allows the second face 35 to comprise the product- defining face of the mould.

Of course the thickness of the sheet 25 must be taken into account when the second face 35 will comprise the product-defining face ofthe mould because, for example, in 1 0 this embodiment the mould cavity 40 will be reduced in size when compared to the corresponding cavity 45 on the primary mould former 10. In addition, particularly with cavities with deep sides there may be thinning of the sheet material 25 as it conforms to the cavity, which must also be taken into account.

Once the newly formed mould 50 has cooled the second face 35 is coated, in this embodiment with a chrome plating 55. The chrome plating 55 is applied to the second face 35 because the face 35 will subsequently serve as the moulding surface of the mould 50. As shown in Figure I e, the chrome plating 55 may be applied whilst the mould 50 is supported in its required shape on the primary mould former 10.

2 0 However, usually the mould 50 will be removed from the former 10 and transported to a specialised chrome plating facility.

ee.e 8 e e * * 8 e 81 8 8 e 8 ee e * e 8 e 8 see eve e Once the sheet 25 has been formed into a mould it needs to be capable of functioning as a mould following removal from the primary mould former l 0. That is, the mould is used to form products without being retained on the mould former. In this way, multiple moulds can be sequentially produced on a single mould former and positioned at different sites for separate use.

The chrome plating gives no structural benefits and therefore, because the mould SS is quite thin, even though it is coated it is still flexible and its shape is not stabilised. In this form the mould 50 could easily be mix-shaped and would not be stiffenough for use as a mould. In other embodiments (not shown) the mould SS is thick enough and/or formed from a material such that it is self-supporting and of sufficient stiffness to allow it to function as a mould with no additional support or strengthening.

in order to allow the first face 30 of the mould 50 to be coated without losing shape the newly coated mould 50 is transferred to a reverse cut secondary mould former 60 comprising the corresponding male shape to the female shape of the primary mould former lo. Accordingly the coated second face 35 ofthe mould 50 is in contact with and supported by the secondary mould former 60, as shown in Figure l f. The first face 30 of the mould 50 is now coated with a foam backing 65. Figure l g shows the 2 0 completed open face female mould 50 following chrome plating and stabilising.

The mould 50 could now undergo further processing to allow it to be used as a mould.

For example, vacuum ports could be machined to the mould 50 to allow the mould 50 to be used for vacuum forming of components. Alternatively, other forms of 8 e 8.

e e 8 e e 8,8 e e e 8 e 8 - e 8 8 . e.-8 8 processing could be used to prepare the mould 50 for use in conjunction with resin impregnated composite materials which may be applied to the mould in a liquid state before hardening occurs.

Once formed and processed as required the mould 50 could be used to form a product.

Material for forming a product is introduced into the mould cavity and allowed to set before being removed from the mou]d. The mould may be suitably coated to assist removal of the product.

0 Referring now to Figure 2a there is shown an open face female mould l SO which has been prepared on a female primary mould former l 10 in exactly the same way as the mould 50 shown in Figures 1ato id. In order to allow the mould l50to form pert ofa closed face moulding system a product blank 170 is formed onto the second face 135 of the sheet 125 of the mould 150 mould 150 (Figure 2b). This is achieved by first machining vacuum ports 121 into the sheet 125 to allow the blank 170 to be vacuum formed from thermoplastic material, as shown in Figure 2b. In other embodiments (not shown) the blank is not vacuum formed and could be hand-shaped or otherwise produced without requiring modifications to the mould 150.

2 0 With the blank l 70 in place the a sheet 185 of thermoplastic material having first 187 and second 189 faces is now used to vacuum form a backing mould 180 having a shape corresponding to the mould 150 with the blank 170 inserted, in a sequential moulding operation.

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Following moulding of the mould 150 and the backing mould 180 they may be subjected to the same post-mould processing as the mould 50 shown in Figures la to Ig,so that each sheet 125, 185 may have a product-defining face 135, 187 whichis plated with a chrome layer 155, 190 and an opposite face 130, 189 which has a stabilising foam backing 165, 195, as shown in Figure 2d.

Referring now to Figure 2e it will be appreciated that with the blank 170 removed, once the mould 150 and the backing mould 180 are again brought together a cavity will be formed which corresponds in shape to the blank 170. Thereafter the moulds 150, 180 can be used, for example, for composite material moulding techniques such as resin transfer moulding in which a product pre-form comprising a fibre-based material, such as glass or carbon fibre, is placed in the mould cavity 175 and resin, such as a polyester or epoxy resin, is injected to fill the cavity. When the moulds 150, 180 are separated a cured product having the shape of the mould cavity 175 can be removed.

Referring now to Figures 3a to 3i there is shown a method of mould and product manufacture according to an alternative embodiment of the present invention.

2 0 In Figure 3a a primary mould former in the form of a vacuum forming tool 210 is provided.

A thin film of material 225 is provided. In this embodiment the sheetlike material 225 comprises a polyester f lm having a thickness of approximately I mm.

- e e e ë e e e ee e . e ë The sheet 225 is vacuumed onto the mould fonmer 210 as shown in Figure 3b. One of two things can then happen to the newly fonned mould 250. In the first case, the mould 250 can be used to create a reusable backing structure in the steps shown in Figures 3c to 3e. This would be appropriate if the mould 250 is too flexible to become a free-standing moulding facility requiring no physical support in order to maintain its form during subsequent moulding operations. Alternatively, if the mould 250 was self-supporting then it could proceed straight to the steps shown in Figures 3h and 3i.

In the case of a mould requiring a backing structure, following the step shown in Figure 3b the mould 250 is retained on the former 210.

As shown in Figure 3c a box-like structure 205 is placed over the former 210 and casting material 206 is poured into the box 205.

Once the casting material 206 has cured the mould 250 is left on the casting 206 and lifted away from the former 210.

The result of the moulding operation of Figure 3c is shown in Figure 3d and 2 0 comprises a forming tool 207 comprising the mould 250 resting on the casting 206.

The tool 207 can then be used to form the backing structure 260 shown in Figure 3e.

It will be noted that it is the first face 230 of the film 225 which is used as the template for the backing structure 260. Accordingly the backing structure 260 is see o.. c a

a ëv a. V v as -e ë r exactly the right shape and size to subsequently receive the f rst faces 230 of formed moulds 250.

In Figure 3 f the backing structure 260 is shown inverted and ready to receive a mould 250 of the type produced in Figures 3a and 3b having been removed from the former 210.

In Figure 3g the mould 250 is shown seated in the backing structure 260. With the mould 250 supported in this way material 208 for moulding a product is introduced into the mould 250.

Once the material 208 has cured the mould 250 can be removed from the backing structure 260 as shown in Figure 3h.

1 5 In this embodiment, the mould 250 is disposable and functions as a primary packaging material for the newly formed product 209. Accordingly, the product 209 has an existence separate from the mould and the mould does not form part of the product; the product can be subsequently removed from the mould 250 as shown in Figure 3i.

2 0 Therefore in this method the mould can serve to produce a reusable backing structure and as a disposable mould which can be used as a primary packaging material. Be...

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In a variation on the above method, at the steps shown in Figure 3fthe mould 250 can be pre-loaded with cloth and other material prior to adding it to the support backing structure 260 to save time in a moulding process such as a composite material moulding process.

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Claims

CLAllVIS 1. A method of producing a mould for a product, the method

comprising the steps of providing a sheet of material having first and second faces and forming the sheet onto an open face primary mould former having a shape corresponding to a required shape for the would with the first face of the sheet in contact with the former, wherein the second face of the thus- formed sheet is utilised to determine the shape of the subsequently moulded product.
2. A method as claimed in claim l, in which the sheet material comprises a thermoformable material.
3. A method as claimed in claim I or claim 2, in which the sheet material comprises a thermoformable plastics material.
4. A method as claimed in any of claims I to 3, in which the sheet material comprises acrylonitrate-butadiene-styrene.
5. A method as claimed in any preceding claim, further comprising the step of 2 0 coating one or both of the first and second faces of the sheet.
6. A method as claimed in claim 5, in which the second face of the sheet is coated with a metallic surface finish. e
7. A method as claimed in claim 5 or claim 6, in which the second face of the sheet is plated with chrome.
8. A method as claimed in any of claims 5 to 7, in which the coating stabilises the shape of the mould.
9. A method as claimed in any preceding claim, further comprising the step of laying the mould onto a secondary mould former oppositely shaped to the primary mould former such that the first face ofthe sheet is exposed thereby allowing it to be coated whilst supported in its required shape.
10. A method as claimed in any preceding claim, in which the primary mould former and the mould are of a female configuration.
1 1. A method as claimed in any preceding claim, in which the mould is of an open face female configuration.
12. A method as claimed in any preceding claim, in which the sheet is formed onto the primary mould former by vacuum forming.
13. A method as claimed in any of claims I to 11, in which the sheet is formed onto the primary mould former by press forming.

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14. A method according to any preceding claim, further comprising the steps of adding a blank having the shape of the product to the second face of the mould sheet, and forming a backing mould onto the mould sheet and the blank from a sheet of material having first and second backing faces with the first backing face in contact with the mould sheet and the blank, to produce a closed face mould for producing a product having the shape of the blank.
15. A method as claimed in claim 14, further comprising the step of coating one or both of the first and second backing faces of the backing mould sheet.
16. A method as claimed in claim 15, in which the first backing face of the backing mould sheet is coated with a metallic surface finish.
17. A method as claimed in claim 15 or claim 16, in which the first backing face of the backing mould sheet is plated with chrome.
18. A method as claimed in any of claims 15 to 17, in which the coating stabilises the shape of the backing mould.

2 0
19. A method as claimed in any of claims 14 to 18, further comprising the step of laying the backing mould sheet onto a tertiary mould former oppositely shaped to the mould with the blank in place, thereby allowing the second face ofthe backing mould sheet to be coated whilst supported in its required shape.

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20. A method as claimed in any of claims 14 to 19, in which the backing mould material comprises a thermoformable material.
21. A method as claimed in any of claims 14 to 20, in which the backing mould material comprises a thermoformable plastics material.
22. A method as claimed in any of claims 14 to 21, in which the backing mould material comprises acrylonitrate-butadiene-styrene.
23. A method as claimed in any of claims 14 to 22, in which the backing mould sheet is formed onto the mould and the blank by vacuum forming.
24. A method as claimed in any of claims 14 to 22, in which the sheet is formed onto the mould and the blank by press forming.
25. A method of producing a mould for a product, the method comprising the steps of preparing an open face primary mould former having a shape corresponding to a required shape for the mould, providing a sheet of material having first and second faces, forming the sheet onto the primary mould former with the first face in contact 2 0 with the former, and thereafter utilising the second face of the thus- formed sheet to determine the shape of a subsequently moulded product.
26. A method as claimed in any preceding Claim, further comprising the step of using the mould to form a product.

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27. A method of producing a moulded product comprising the steps of: providing a sheet of mould material having first and second faces and forming the sheet onto a primary mould former with the first face of the sheet in contact with the former; removing the thus-formed mould from the primary mould former; and using the second face of the sheet to receive material to be moulded into a product.
28. A method as claimed in Claim 26 or Claim 27, further comprising the step of removing a formed product from the mould.
29. A method of producing a reusable mould comprising the steps of: providing a sheet of mould material having first and second faces; and forming the sheet of mould material having first and second faces; and forming the sheet onto an open face primary mould former having a shape corresponding to a required shape for the mould with the first face in contact with the former; in which the second face of the thus- formed mould is utilised to determine the shape of subsequently moulded products.
30. A method as claimed in any preceding Claim, in which the shape ofthe mould is determined entirely by virtue of contact with the first face such that there is no contact with the second face as it is formed into the product shape determining 2 0 surface.
31. A method as claimed in any preceding Claim in which the mould is adapted to comprise removable packaging means for a subsequent moulded product.

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32. A mould produced by a method according to any preceding Claim.
33. A product formed by a mould produced by a method according to any of Claims I to 31.
34. A method substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.
35. A product substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

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