GB2435848A

GB2435848A - Mould skins

Info

Publication number: GB2435848A
Application number: GB0603007A
Authority: GB
Inventors: Jed Richter
Original assignee: Advanced Composites Group Ltd
Current assignee: Cytec Industrial Materials Derby Ltd
Priority date: 2006-02-15
Filing date: 2006-02-15
Publication date: 2007-09-12
Also published as: GB0603007D0

Abstract

A preformed mould skin is shaped to conform to a mould surface of a mould to form a moulded component 14. There may be a set of preformed mould skins, such as a pair or cassette of mould skins (10a, 10b) for use in moulding material in a mould (12) to form a moulded component (14), the mould skins (10a, 10b) being shaped to conform to a respective mould surface (16a, 16b) of the mould (12). Also provided is a method of moulding material between at least two surfaces of a mould to form a moulded component (14), the method comprising locating a preformed skin (10a, 10b) between the material to be moulded and at least one of the mould surfaces, the skin being shaped to conform to the mould surface. Fibre reinforced resinous material may be moulded under heat and pressure in press moulds, which comprise upper and lower moulds defining mould surfaces as above. Figures 2a-2j illustrate a sequence of steps for forming a mould skin and there are claims to forming skins.

Description

Mould Skins The present invention relates to mould skins and

particularly but not exclusively to mould skins for use in press moulding of fibre reinforced resinous materials.

Press moulding is a technique used to form components from fibre reinforced resinous materials. It produces high quality components, but the presses and moulds are expensive and therefore need to be in use as much as possible.

Press moulds essentially comprise two press plates, usually positioned one above the other. Each plate comprises a mould defining a mould surface.

The mould surfaces on the respective plates generally face each other. In use, components are formed between the mould surfaces generally as follows.

Uncured or partially cured fibre reinforced resinous material is laid up on the lower mould surface. The material may comprise fibrous material pre-impregnated with resinous material, or discrete layers of dry fibre and resin, or combinations of both. The methods for laying up such materials and the different types and combinations of materials are well known to those skilled in the art.

Once the material is laid up in the mould, the press plates are actuated to bring and press the mould surfaces together to mould the material therebetween to the desired shape.

When the materials comprise uncured or partially cured resin systems, heat is typically also applied to cure or facilitate cure of the material within the mould. The mould surfaces are typically heated according to known techniques.

The conditions of heat and pressure are applied over a predetermined cure cycle, which is typically governed by the thickness of the material being cured and the chemistry of the resin(s) in the material.

At the end of the cure cycle the moulded component is removed and the mould surfaces cleaned and prepared for subsequent moulding. While the cleaning and preparation is taking place, the press and mould lie idle, in that they cannot be used to mould further components. It is undesirable for such expensive equipment to be idle for such periods of time. Further, during this time the mould is losing heat. This introduces energy inefficiencies and also adds to the interval between successive moulding operations due to the need for the mould to warm up again to the operative temperature.

It is also found that to prevent undesirable distortion of moulded components, the component has to be allowed to cool down before being removed from the mould. This again adds to the time interval between successive moulding operations and thus reduces the effective moulding time of the equipment.

According to the present invention there is provided a preformed mould skin for use in moulding material in a mould to form a moulded component, the mould skin being shaped to conform to a mould surface of the mould.

Preferably the mould skin is rigid or semi-rigid and conforms substantially exactly to the shape of the mould surface. Preferably the mould skin is resistant to distortion upon changes of temperature, particularly across the range of temperatures at which it is intended for use, which for moulding fibre reinforced resinous materials is typically in the range of room temperature (18-30 C) to 100- 180 C. The mould skin is preferably comprised of material that gives the skin an overall thermal expansion coefficient of zero or substantially zero. The mould skin may be formed of carbon fibre reinforced resinous composite material.

Preferably the mould skin provides a moulding surface against which material is moulded, in use. Preferably the mould skin is arranged to facilitate heat transfer from the mould surface to material being moulded thereagainst.

The mould skin is preferably comprised of good thermal conducting material, preferably at least over the moulding surface and is preferably formed to be as thin as functionally possible over the region thereof defining the moulding surface, to facilitate heat transfer.

Preferably the mould skin is formed to support a component moulded thereagainst for removal from the mould. The mould skin is preferably sufficiently rigid to prevent significant distortion of the moulded component held thereby, particularly as the component cools down from the cure temperature.

The mould skin may comprise one or more formations or other features that facilitate handling thereof, particularly when bearing material, both before and after moulding. Handle formations may be moulded or otherwise provided on the mould skin. The mould skin may include other features to facilitate moulding, for example a thermocouple to enable the mould temperature to be monitored, curing sensors, location formations to facilitate location of the skin in the mould and/or against another skin, coated surfaces to aid release or extend mould and/or mould skin life and any other known tooling features.

According to a second aspect of the present invention there is provided a set of mould skins, each mould skin being substantially as defined in any of the preceding five paragraphs.

Preferably a mould skin set is used to define moulding surfaces against which material can be moulded, for example in press moulding apparatus.

Preferably mould skins in a set define moulding surfaces shaped to conform to each other so that material can be moulded to a predetermined conformation therebetween.

Preferably one mould skin in a set is shaped to conform to and located at least in part, into another mould skin in the set. Preferably the said one mould skin is locatable in the said other mould skin, in use, over the region(s) thereof defining the moulding surfaces.

Preferably a mould skin set comprises two mould skins.

According to a third aspect of the present invention there is provided a method of moulding material between at least two surfaces of a mould to form a moulded component, the method comprising locating a preformed skin between the material to be moulded and at least one of the mould surfaces, the skin being shaped to conform to the mould surface.

The mould skin used is preferably preformed in a rigid or semi-rigid condition to locate on said mould surface to form a layer or skin over the mould surface and thereby itself define a moulding surface on which the material will be moulded.

Preferably the material to be moulded is laid up on the mould skin before the mould skin is located in the mould.

The mould surface and/or the mould skin may be treated with a release agent to facilitate the release of the mould skin from the mould following moulding. The moulding surface of the mould skin may also be treated to facilitate removal of a moulded component therefrom.

Preferably the mould skin and the moulded component are removed from the mould together following moulding. Preferably the mould skin acts to prevent significant distortion of the moulded component following removal from the mould, particularly as the moulded component cools.

The mould skin used may be as described in any of paragraphs nine to thirteen above.

Preferably a set of mould skins, which may comprises a pair or cassette of mould skins is used between which the material is moulded. The second mould skin may be shaped to generally complement and may conform to the said one mould skin so that a space is defined between the skins in which the material is formed to the shape of the desired component. The second mould skin is preferably preformed to conform to the shape of a second mould surface against which it is located in use.

Preferably the set of mould skins and each mould skin therein is substantially as described in any of paragraphs fourteen to eighteen above.

Preferably the method further comprises compressing the material between the skins or the skin and a further mould surface, at predetermined pressure conditions. Preferably the method comprises the application of heat to the material to cure the material, particularly when the material being moulded is a fibre reinforced resinous material comprising uncured or partially cured resin.

If a second skin is used this is preferably located over the material on the first mould skin to sandwich the material therebetween, outside the mould.

Preferably the mould skin(s) and material are located together into a mould, for location against respective mould surfaces, preferably while the mould surfaces are at or near the desired moulding temperature. This helps to reduce the mould and cure time.

Preferably the mould skin(s) used are comprised of material that gives them an overall expansion coefficient sufficiently low to prevent any thermal expansion or distortion of the skin(s) between moulding temperature, which is typically in the order of 100-180 C, and room temperature (18 C-30 C).

Preferably the mould skin(s) have an in-plane thermal expansion coefficient of zero or substantially zero.

Preferably where more than one mould skin is used, they are comprised of the same material(s) to give them the same thermal expansion characteristics.

Preferably the mould skin(s) and moulded component are removed together following, and desirably upon, completion of moulding. This frees up the mould surfaces for the immediate location of further preloaded skins. The skins prevent contamination of the plates such that there is no need to clean the mould plates or apply mould release coatings following moulding.

Preferably the moulded component is left for a predetermined time on or between the moulded skin(s) to cool. The moulded skins preferably act to prevent any undesirable distortion of the component during cooling.

According to a fourth aspect of the present invention there is provided a method of manufacturing a mould skin, the method comprising forming a master component between surfaces of a mould, removing said master component, removing surface material from one of said surfaces to a shape and depth to form a space corresponding to the desired shape and thickness of the mould skin to be manufactured, locating mould skin material in said space and subjecting the mould skin material to conditions to form the mould skin.

Preferably the mould skin material is subjected to conditions of heat and/or pressure to mould the material and, where the material comprises curable material, to cure the material to a desired state.

Preferably the master component is replaced in the mould to sandwich the mould skin material against the mould surface. Preferably sufficient material is located so as to substantially fill the space.

Preferably material is removed from the said surface by machining, such as CNC machining. The depth of surface material removed may vary at different locations over the surface, depending upon desired characteristics for the mould skin to be produced. For example, in areas where the mould skin will mould material, the thickness thereof may only be relatively thin to facilitate heat transfer to the material being moulded, in which case the amount of surface material removed is relatively small. In other areas, where greater thickness of the mould skin is required, for example where particular strength or support is needed, the amount of material removed can be greater.

According to a fifth aspect of the present invention there is provided a method of manufacturing a pair of mould skins for use in moulding material therebetween, the method comprising: forming a master component between surfaces of a mould, removing said master component, removing surface material from one of said surfaces to define a space in which a mould skin is to be moulded, locating mould skin material in said space and replacing the master component such that the mould skin material is located between said surface and the master component and subjecting the material to conditions within the mould to form the first mould skin, removing surface material from a second of said surfaces to define a second space in which a second one of the mould skins is to be moulded, locating mould skin material in said second space to be between said second surface and the master component, and subjecting the material to conditions within the mould to form the second mould skin.

Preferably the said first mould skin is located against one side of the master component while the second skin is formed on the other side such that when the skins are used together to mould a component therebetween as described above, the component formed therebetween is the same shape as the master component.

The second mould skin may be moulded with the first mould skin located in the mould.

According to a sixth embodiment of the present invention there is provided a method of manufacturing a plurality of mould skins, comprising forming a master component between surfaces of a mould, removing said master component from between said surfaces, removing surface material from at least two of the said surfaces of the mould to define respective spaces in which respective mould skins are to be formed locating mould skin material in said spaces to be between said surfaces and the master component placed therebetween, and subjecting the mould skin material to conditions within the mould to form a plurality of mould skins.

Preferably the mould skins are as described above in any of paragraphs nine to eighteen above.

Preferably each mould skin is formed substantially as described in any of paragraphs thirty four to thirty seven above.

Various embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings in which:-Fig. 1 a is a perspective view of the first of a pair of mould skins according to the present invention; Fig. 1 b is the second of a pair of mould skins according to the present invention; Figs. 2a-q are diagrammatic illustrations of various stages in the process of manufacture of mould skins according to the present invention; and Fig. 3 is a diagrammatic cross-section of mould skins in use within a mould to form a moulded component.

The present invention relates to mould skins, a method of producing mould skins and a method of moulding using mould skins.

Referring to the drawings, in particular figures la, lb and 3, there is provided a set of preformed mould skins, in this case a pair or cassette of mould skins 10a, lOb for use in moulding material in a mould 12 to form a moulded component 14, the mould skins 1 Oa, 1 Ob being shaped to conform to a respective mould surface 1 6a, 1 6b of the mould 12.

In this embodiment, a pair of mould skins 10a, lOb is described, but it will be appreciated that one or more than two mould skins may be used in accordance with the present invention.

Each mould skin 1 Oa, 1 Ob is rigid or semi-rigid and conforms substantially exactly to the shape of the mould surface 1 6a, 1 6b against which it locates in use. In this embodiment the shape of the mould skin is relatively simple, but it will be appreciated that the skins can be formed to any suitable shape to provide moulded components of desired conformation.

Each skin lOa, lOb, defines a moulding surface 19a, 19b against which material is moulded in use, as described below. The moulding surface 1 9b of the skin lOb is shaped to locate within and conform to the moulding surface 19a.

When the skins 1 Oa, 1 Ob are so located for use, a space is defined therebetween which corresponds to the shape of the component to be moulded between the skins lOa, lOb.

Each mould skin 1 Oa, 1 Ob is manufactured from material to give the skin an overall in-plane thermal expansion coefficient of zero or substantially zero. A suitable material that can be used is carbon fibre reinforced resinous composite material.

It is important that at least one of the mould skins has such properties, so that the skin is resistant to distortion upon changes of temperature, particularly across the range of temperatures at which they are intended to use. For the moulding of fibre reinforced resinous materials the typical use ranges would be room temperature (18-30 C) to 100-180 C, as will be described. It is preferred that both skins exhibit such characteristics and moreover that they have the same expansion coefficient. Thus the skins would generally be made of the same material.

Each skin is manufactured from material that facilitates the transfer of heat from heated mould surfaces to the material being moulded. This is particularly useful where the material being moulded requires heat to cure during moulding.

The moulding of composite components from fibre reinforced resinous materials is a particular application of the present invention. Again, the use of carbon fibre reinforced resinous composites provides for good heat transfer between the heated mould surfaces and the material being moulded.

The mould skins lOa, lOb may also be shaped or otherwise formed to facilitate heat transfer. For example, the thickness of the mould skin can be kept to a functional minimum over areas where heat transfer is most desired.

The mould skins may comprise formations that facilitate handling thereof, particularly when loaded with material, both before and after moulding. Handle formations 18 may be provided in this regard. In this embodiment, these formations are relatively simple flanges and extensions of the side portions of the moulded skins lOa, lOb. However of course, these formations can be of any suitable shape and desired configuration.

The mould skins may also comprise further features (not shown) to facilitate moulding. For example, one or more thermocouples may be embodied within the skins to enable the mould temperature to be monitored. Curing sensors may also be provided as may location formations to facilitate location of the skins in the mould and/or against each other. Surface coatings may be provided to enhance the usable life of the mould and/or to facilitate release of a moulded component from the skin and/or of the skin from the mould.

The invention further provides a method of moulding material between at least two surfaces of a mould to form a moulded component 14, the method comprising locating a preformed skin 1 Oa, 1 Ob between the material to be moulded and at least one of the mould surfaces, the skin being shaped to conform to the mould surface.

In more detail, in this embodiment the pair of mould skins lOa, lOb can be used in the formation of a moulded component within a mould.

Referring to Fig. 3, the mould 12 comprises an upper mould body 1 2a that defines an upper mould surface 1 6a. The mould also comprises a lower mould body 1 2b which defines a lower mould surface 1 6b.

The mould skin lOa is shaped to conform substantially exactly to the shape of the upper mould surface 1 6a, to provide a tight but releasable fit thereof against the surface 1 6a.

The mould skin 1 Ob is similarly shaped to conform substantially exactly to the lower mould surface 1 6b, as can be seen in Fig. 3.

The mould skins lOa, lOb are also shaped so that when the upper and lower mould bodies 12a and 12b are brought together with the skins lOa, lOb located for position within the mould, a space is defined between the mould skins lOa, lOb which corresponds to the shape to which the component is to be moulded therein, such that when that space is filled with material to be moulded and that material is moulded according to predetermined moulding conditions, a moulded component is formed between the skins 1 Oa, 1 Ob.

In more detail, the mould skins lOa, lOb of the present invention can be used to mould various types of material therebetween. One particular example is use to mould fibre reinforced resinous material within press moulds. Press moulds generally comprise upper and lower moulds defining mould surfaces as described above. Conventionally, material is located directly between these mould surfaces and conditions of heat and pressure are applied to mould material between those surfaces. However, conventional techniques suffer from significant disadvantages.

Such press moulds are expensive items of equipment and therefore there is a desire for them to be in use as often as possible. However, moulding according to conventional techniques means that for a significant proportion of the time, the mould surfaces are being cleaned and release agents applied between successive mouldings.

Moreover, for fibre reinforced resinous materials, it is desirable to leave the moulded component within the mould until it has cooled to some degree, otherwise the moulded component is susceptible to distortion as it cools outside the mould. During this time, the mould cannot be used to mould a further component. Further, the temperature of the mould is dropping and needs to be elevated again to cure temperature during a subsequent mould. This is both time and energy inefficient.

Moreover, further cooling of the mould occurs during subsequent cleaning of the mould surfaces, which again introduces more time and energy inefficiency.

The mould skins and the methodology of the present invention address these disadvantages.

Material to be moulded can be laid up on the moulding surface 1 9b of the lower mould skin 1 Ob, outside of the mould. If appropriate, the mould material can be sandwiched between the moulding surfaces 19a and 19b of the mould skins 1 Oa, 1 Ob outside the mould. A suitable release agent, known in the art, can be used between the mould skins and the material to facilitate subsequent release of the mould component. This can enable laid up material to be stored outside the mould in appropriate conditions for subsequent use, thus introducing further efficiencies of production. Alternatively, the moulding surfaces 1 9a, 1 9b may themselves be such as to facilitate subsequent release of the mould component therefrom.

The thermal expansion properties of the mould skins lOa, lOb mean that they can be loaded into a mould whilst the mould is at moulding temperature, without any significant distortion when the mould skins 1 Oa, 1 Ob are subjected to such sudden increases in temperature from storage temperature (usually room temperature or below, to 100 C to 180 C, or above).

Once the mould skins 1 Oa, 1 Ob and material to be moulded are loaded into the mould, the two parts 12a, 12b can be brought together, to exert pressure on the skins 1 Oa, 1 Ob and the material to compress it and shape it according to the space defined between the skins 1 Oa, 1 Ob. Release agent may be used between the skins 1 Oa, 1 Ob and the mould parts 1 2a, 1 2b to facilitate subsequent release following moulding.

The temperature of the mould bodies 1 2a, 1 2b, and in particular the mould surfaces 16a, 16b are controlled to provide the desired moulding and cure temperature for the material. The shape and thermal conductivity characteristics of the mould skins are such to facilitate heat transfer from the mould surface 1 6a, 1 6b to the material being moulded to facilitate moulding and cure.

Once the cure cycle is complete, the mould skins lOa, lOb and the moulded component 14 therebetween can be removed from the mould 12, without the need to allow the moulded component 14 to cool. The rigid or semi-rigid properties of the mould skins lOa, lOb, along with their resistance to distortion as a consequence of temperature changes, enables the mould skins 1 Oa, 1 Ob to act to prevent distortion of the moulded component 14. This means that the mould 12 can be vacated quickly and efficiently and released for the moulding of further components, between a further pair of mould skins.

The mould skins 1 Oa, 1 Ob also act to prevent contamination of the mould surfaces 1 6a, 1 6b with the material being moulded. There is therefore little or no need for any cleaning of the mould surfaces between successive moulding operations.

It is envisaged that a number of sets of mould skins will be provided to allow for most efficient use of the mould 12. The precise number can vary and may be determined by the cure cycle of the component being moulded.

The mould skins 1 Oa, 1 Ob can be cleaned once the moulded component is released therefrom following appropriate cooling. They can be cleaned for re-use if appropriate.

With reference to Figs. 2a -2q, the invention also provides a method of manufacturing a mould skin, the method comprising forming a master component between mould surfaces 12c and 12d of a mould 12, removing said master component, removing surface material from one of said surfaces to a shape and depth to form a space corresponding to the desired shape and thickness of the mould skin to be manufactured, locating mould skin material in said space replacing the master component and subjecting the mould skin material to conditions to form the mould skin.

In more detail, Figs. 2a -2j comprise a sequence of diagrams illustrating a method of forming a mould skin according to the present invention.

Fig. 2a shows the first step of forming the mould surfaces 1 2c and 1 2d of the upper and lower mould bodies 12a, 12b respectively. CNC machine heads 22 are shown cutting the mould surfaces 1 2c, 1 2d to the desired shape.

Once the surfaces 1 2c and 1 2d are formed, master component material 24 is laid over the mould surface 12d, as shown in Fig. 2b. The upper and lower mould bodies 12a, 12b are then brought together as illustrated in Fig. 2c to sandwich and mould the material 24 therebetween. Heat and pressure conditions are applied, according to the master component material being moulded over a predetermined mould cycle (Fig. 2d).

Once the mould cycle is complete, the master component 20 is released from between the mould bodies 12a, 12b as shown diagrammatically in Fig. 2e.

Once the master component 20 is formed, one of the surfaces 12c, 12d is further machined using the CNC head 22 to remove material therefrom over an area and to desired depth(s) to form a space corresponding to the desired shape and thickness of the mould skin to be manufactured. Fig. 2f shows the mould surface 12c being machined, which will result in the formation of the upper mould surface 16a.

Mould skin material, which preferably comprises carbon fibre impregnated uncured resinous material 26 is layered over the master component 20 as illustrated in Fig. 2g. The master component 20 bearing this material 26 is then located back over the surface 1 2d of the mould part 1 2b and the the mould parts 1 2a, 1 2b closed together to sandwich the master component 20 and the mould skin material 26 therebetween, to mould the mould skin material 26 between the master component 20 and the surface 16a (see Fig. 2h).

The mould skin material 26 is then subjected to predetermined cure conditions of heat and/or pressure (Fig. 2i). Once the moulding and cure cycle are complete, the master component 20 and the mould skin lOa are released from between the mould bodies 12a, 12b, as shown diagrammatically in Fig. 2j.

The mould skin 1 Oa can then be conditioned and further processed into a form for use. For example, its surfaces and edges can be cleaned and/or polished as necessary to form a high quality moulding surface for use.

Although it is within the scope of the present invention for a single mould skin to be used in a mould, it is preferable that mould skins are used in sets, which in most instances will be pairs so that material can be moulded therebetween. Figs. 2k -2p show the steps of producing the second mould skin 1 Ob in accordance with the present invention. With reference to Fig. 2k, the surface 12d is machined using the CNC

machine head 22 to remove material therefrom to form the mould surface 1 6b.

The surface 12d is machined to remove surface material therefrom to a depth and to a shape to form a space corresponding to the desired shape and thickness of the desired mould skin 1 Ob.

Mould skin material 28 is then layered within the master component 20 as illustrated in Fig. 21 and the two mould bodies 12a, 12b brought together. In Fig. 2m the first mould skin 1 Oa is also located over the master component 20, to locate between the master component 20 and the mould surface 1 6a to facilitate moulding. The mould skin material 28 is then subjected to a predetermined mould and cure cycle, including conditions of predetermined pressure and temperature, as illustrated diagrammatically in Fig. 2n.

Once the mould and cure cycle are complete, the mould skin 1 Ob is formed and can be released along with the mould skin 1 Oa and the master component 20 from the mould 12.

A pair of mould skins lOa, lOb is thereby produced for use in moulding material therebetween in accordance with the methodology of the present invention.

The mould skins lOa, lOb can then be released from the master component 20 as illustrated diagrammatically in Fig. 2p, and then conditioned by way of polishing of surfaces and cleaning of edges, as illustrated diagrammatically in Fig. 2q.

Various modifications may be made without departing from the spirit or scope of the present invention.

A plurality of mould skins can be produced simultaneously. For example a master component is formed as described above between surfaces of a mould.

Material is then removed from at least two of those surfaces to define respective spaces in which respective mould skins are to be formed. Mould skin material is located in said spaces. Generally this will be done by locating mould skin material in lower space(s), replacing the master component over the located mould skin material, and then locating further mould skin material either in the remaining space(s) or on the master component. The mould parts are then brought together to sandwich the mould skin material in the respective spaces between the mould surfaces and the master component. The mould skin material in the respective spaces can then be subjected to appropriate cure conditions to cure the material, thus forming the mould skins simultaneously.

For example, although it is preferred for at least two mould skins to be used to form components therebetween, a single skin could be used to mould a component between the skin and a surface of a mould.

Further, a set of skins comprising three or more skins could be used to mould material therebetween.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

Claims: 1. A preformed mould skin for use in moulding material in a

mould to form a moulded component, the mould skin being shaped to conform to a mould surface of the mould.
2. A preformed mould skin according to claim 1, in which the mould skin is rigid or semi-rigid and conforms substantially exactly to the shape of the mould surface.
3. A preformed mould skin according to any preceding claim, in which the mould skin is resistant to distortion upon changes of temperature, particularly across the range of temperatures at which it is intended for use, which for moulding fibre reinforced resinous materials is typically in the range of room temperature (1 8-30 C) to 100-180 C.
4. A preformed mould skin according to any preceding claim, in which the mould skin is comprised of material that gives the skin an overall thermal expansion coefficient of zero or substantially zero.
5. A preformed mould skin according to any preceding claim, in which the mould skin is formed of carbon fibre reinforced resinous composite material. * S.
6. A preformed mould skin according to any preceding claim, in which the *.S.

mould skin provides a moulding surface against which material is moulded, in use. S..
7. A preformed mould skin according to claim 6, in which the mould skin is arranged to facilitate heat transfer from the moulding surface to material being :3o moulded thereagainst.
8. A preformed mould skin according to claim 6 or claim 7, in which the mould skin is comprised of good thermal conducting material, at least over the moulding surface.
9. A preformed mould skin according to any of claims 6 to 8, in which the mould skin is formed to be as thin as functionally possible over the region thereof defining the moulding surface, to facilitate heat transfer.
10. A preformed mould skin according to any preceding claim, in which the mould skin is formed to support a component moulded thereagainst for removal from the mould.
11. A preformed mould skin according to claim 9, in which the mould skin is sufficiently rigid to prevent significant distortion of the moulded component held thereby, particularly as the component cools down from the cure temperature.
12. A preformed mould skin according to any preceding claim, in which the mould skin comprises one or more formations or other features that facilitate handling thereof, particularly when bearing material, both before and after moulding.
13. A preformed mould skin according to claim 12, in which handle formations are provided on the mould skin.
14. A preformed mould skin according to any preceding claim, in which the * mould skin includes other features to facilitate moulding, such as a thermocouple to enable the mould temperature to be monitored, curing sensors, location S...

formations to facilitate location of the skin in the mould and/or against another skin, coated surfaces to aid release or extend mould and/or mould skin life. S.
15. A set of mould skins, each mould skin being substantially comprising a preformed mould skin as defined in any of the preceding claims.
16. A set of mould skins according to claim 15, in which moulding surfaces are defined against which material can be moulded, for example in press moulding apparatus.
17. A set of mould skins according to claim 16, in which mould skins in a set define moulding surfaces shaped to conform to each other so that material can be moulded to a predetermined conformation therebetween.
18. A set of mould skins according to claim 17, in which one mould skin in a set is shaped to conform to and locate at least in part, into another mould skin in the set.
19. A set of mould skins according to claim 18, in which the said one mould skin is locatable in the said other mould skin, in use, over the region(s) thereof defining the moulding surfaces.
20. A set of mould skins according to any of claims 15 to 19, in which a mould skin set comprises two mould skins.
21. A method of moulding material between at least two surfaces of a mould to form a moulded component, the method comprising locating a preformed skin between the material to be moulded and at least one of the mould surfaces, the skin being shaped to conform to the mould surface.
22. A method according to claim 21, in which the mould skin used is preformed in a rigid or semi-rigid condition to locate on said mould surface to * form a layer or skin over the mould surface and thereby itself define a moulding surface on which the material will be moulded. * SS

ss S 25
23. A method according to claim 21 or claim 22, in which the material to be * *:. moulded is laid up on the mould skin before the mould skin is located in the mould. S. S * I S

SI

::30
24. A method according to any of claims 21 to 23, in which the mould surface and/or the mould skin is treated with a release agent to facilitate the release of the mould skin from the mould following moulding.
25. A method according to any of claims 21 to 24, in which the moulding surface of the mould skin is treated to facilitate removal of a moulded component therefrom.
26. A method according to any of claims 21 to 25, in which the mould skin and the moulded component are removed from the mould together following moulding.
27. A method according to claim 26, in which the mould skin acts to prevent significant distortion of the moulded component following removal from the mould, particularly as the moulded component cools.
28. A method according to any of claims 21 to 27, in which the mould skin used is as defined in any of claims 1 to 14 above.
29. A method according to any of claims 21 to 28, in which a set of mould skins is used between which the material is moulded.
30. A method according to claim 29, in which the set of mould skins is as defined in any of claims 15 to 20.
31. A method according to claim 30, in which a second mould skin is shaped to generally complement and conform to a said one mould skin so that a space is defined between the skins in which the material is formed to the shape of the * ** S desired component. S. * .

* *
32. A method according to claim 31, in which the second mould skin is preformed to conform to the shape of a second mould surface against which it is located in use.
33. A method according to any of claims 21 to 32, in which the method further comprises compressing the material between the skins or the skin and a further mould surface, at predetermined pressure conditions.
34. A method according to any of claims 21 to 33, in which the method comprises the application of heat to the material to cure the material.
35. A method according to any of claims 30 to 34, in which the second skin is located over the material on the first mould skin to sandwich the material therebetween, outside the mould.
36. A method according to any of claims 21 to 35, in which the mould skin(s) and material are located together into a mould, for location against respective mould surfaces, while the mould surfaces are at or near the desired moulding temperature.
37. A method according to any of claims 21 to 36, in which the mould skin(s) used are comprised of material that gives them an overall expansion coefficient sufficiently low to prevent any thermal expansion or distortion of the skin(s) between moulding temperature, which is typically in the order of 100-180 C, and room temperature (1 8 C-30 C).
38. A method according to any of claims 21 to 37, in which the mould skin(s) have an in-plane thermal expansion coefficient of zero or substantially zero.
39. A method according to any of claims 29 to 38, in which where more than one mould skin is used, they are comprised of the same material(s) to give them :: . the same thermal expansion characteristics. a...

S... * 25 :.
40. A method according to any of claims 21 to 39, in which the mould skin(s) *:. and moulded component are removed together following completion of moulding.

41. A method according to claim 40, in which the moulded component is left 1130 for a predetermined time on or between the moulded skin(s) to cool.

42. A method according to claim 41, in which the mould skins act to prevent any undesirable distortion of the component during cooling.

43. A method of manufacturing a mould skin, the method comprising forming a master component between surfaces of a mould, removing said master component, removing surface material from one of said surfaces to a shape and depth to form a space corresponding to the desired shape and thickness of the mould skin to be manufactured, locating mould skin material in said space and subjecting the mould skin material to conditions to form the mould skin.

44. A method of manufacturing a mould skin, according to claim 42, wherein the mould skin material is subjected to conditions of heat and/or pressure to mould the material and, where the material comprises curable material, to cure the material to a desired state.

45. A method of manufacturing a mould skin according to either of claims 43 and 44, in which the master component is replaced in the mould to sandwich the mould skin material against the mould surface.

46. A method of manufacturing a mould skin according to any of claims 43 to 45, in which sufficient material is located so as to substantially fill the space.

47. A method of manufacturing a mould skin according to any of claims 43 to 46, in which material is removed from the said surface by machining, such as CNC machining.

48. A method of manufacturing a mould skin according to any of claims 43 to S...

"25 47, in which the depth of surface material removed varies at different locations I. overthesurface. S..

49. A method of manufacturing a pair of mould skins for use in moulding material therebetween, the method comprising:-forming a master component between surfaces of a mould, removing said master component, removing surface material from one of said surfaces to define a space in which a mould skin is to be moulded, locating mould skin material in said space and replacing the master component such that the mould skin material is located between said surface and the master component and subjecting the material to conditions within the mould to form the first mould skin, removing surface material from a second of said surfaces to define a second space in which a second one of the mould skins is to be moulded, locating mould skin material in said second space to be between said second surface and the master component, and subjecting the material to conditions within the mould to form the second mould skin.

50. A method according to claim 49, in which the said first mould skin is located against one side of the master component while the second skin is formed on the other side such that when the skins are used together to mould a component therebetween, the component formed therebetween is the same shape as the master component.

51. A method according to claim 49 or claim 50, in which the second mould skin is moulded with the first mould skin located in the mould.

52. A method of manufacturing a plurality of mould skins, comprising forming a master component between surfaces of a mould, removing said master component from between said surfaces, removing surface material from at least two of the said surfaces of the mould to define respective spaces in which respective mould skins are to be formed locating mould skin material in said spaces to be between said surfaces and the master component placed therebetween, and subjecting the mould skin material to conditions within the mould to form a plurality of mould skins.

53. A method of manufacturing a plurality of mould skins according to claim 52, in which the mould skins are as defined in any of claims ito 19.

54. A method of manufacturing a plurality of mould skins according to claim 52 or claim 53, in which each mould skin is formed as described in any of claims 43 to5l above.

55. A preformed mould skin substantially as hereinbefore described with reference to the accompanying drawings.

56. A set of mould skins substantially as hereinbefore described with reference to the accompanying drawings.

57. A method of moulding material substantially as hereinbefore described with reference to the accompanying drawings.

58. A method of manufacturing a mould skin substantially as hereinbefore described with reference to the accompanying drawings.

59. A method of manufacturing a pair of mould skins substantially as hereinbefore described with reference to the accompanying drawings.

60. A method of manufacturing a plurality of mould skins substantially as hereinbefore described with reference to the accompanying drawings.

61. Any novel subject matter or combination including novel subject matter a.,.

disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims. I..

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