Vacuum pressing equipment

Abstract

A vacuum pressing apparatus (100) comprising at least:-a support (102) having a first element (104) and a cover (106) movable relative to the first element (104); at least one vacuum source (110) comprising a control unit (114) for actuating the at least one vacuum source and connected to the at least one vacuum port (108) of the support (102); and a vacuum dispensing pad (120) comprising at least: a first porous anti-adhesion sheet (2001) disposed on top of the first element (104) and covering the at least one vacuum port (108); a stack of breathable mesh layers (204) disposed on top of the first porous sheet (2001); and a second porous anti-adhesion sheet (2002) disposed on top of the stack (204) of breathable mesh layers, said second sheet (2002) being connected to the first sheet (2001), said second sheet and said cover being adapted to sandwich the product (1) to be compacted therebetween.

Description

TECHNICAL FIELD

[0001] The present invention relates to a vacuum press apparatus and method for compacting a product. BACKGROUND

[0002] It is known to use a vacuum press apparatus comprising at least: - a support having a first element; - a cover movable between a first position in which the cover is applied to the first element and a second position in which the cover is distanced from the first element; - at least one vacuum source connected to at least one vacuum port of the support; and - a control unit connected to the at least one vacuum source and configured to induce a vacuum between the first element and the cover when the cover is in its second position.

[0003] Such apparatus is for example a debubbling station configured to compact a product, for example a stack of prepreg plies, but not as a limitation. Prepregs are used as a basic building block to manufacture high performance composite structures used for example in the automotive, aerospace and the like. Prepregs are laminated composites formed using fibres sheets impregnated with resin that has not yet fully cured. The fibre sheets are typically made of glass fibres, carbon fibres or polyaramid (Kevlar) fibres.

[0004] Prepregs can be made by creating a layered arrangement of soft and pliable material sheets or plies.

[0005] The layered arrangement of plies can trap air between the plies of the prepreg material. If this air cannot be removed prior to the curing process of the material, it can create defects, for example porosity, in the final cured material or part. These defects can weaken or reduce the quality of the structure made from the defective prepreg.

[0006] A vacuum press apparatus as described above is used to remove such trapped air. However, the debubbling or compacting process applied on the prepreg plies using such apparatus typically does not effectively remove all trapped air.

[0007] It can be desirable to provide a vacuum press apparatus in which the compacting of a product such as a prepreg ply is improved. SUMMARY

[0008] To this end, it is proposed a vacuum press apparatus comprising at least: - a support having a first element; - a lid, the lid being movable between a first position, in which the lid is applied to the first element, and a second position, in which the lid is remote from the first element; - at least one vacuum source, the at least one vacuum source being connected to at least one vacuum port of the support; and - a control unit, the control unit being connected to the vacuum source and being configured to induce a vacuum between the first element and the lid when the lid is in its second position; wherein the vacuum press apparatus further comprises: - a vacuum distribution mat, the vacuum distribution mat comprising at least: • a first porous anti-adhesion sheet, the first porous anti-adhesion sheet having a peripheral edge; • a stack of air-permeable mesh layers, the stack of air-permeable mesh layers being disposed on top of the first porous sheet; and • a second porous anti-adhesion sheet, the second porous anti-adhesion sheet being disposed on top of the stack of air-permeable mesh layers; the second anti-adhesion porous sheet having a peripheral edge; and the peripheral edges of the first and second porous anti-adhesion sheets being connected to each other to embed the stack of layers between the first and second porous anti-adhesion sheets; the vacuum distribution mat being laid on the first element such that: - the first porous anti-adhesion sheet comprises a lower surface applied to an upper surface of the first element and covering the at least one vacuum port, and - the second porous anti-adhesion sheet comprises an upper surface facing a lower surface of the lid when the lid is in its second position, the upper surface of the second porous anti-adhesion sheet and the lower surface of the lid being adapted to sandwich a product to be compacted therebetween.

[0009] According to the invention, a porous sheet is a sheet of material comprising void spaces or pores into which a fluid, such as a gas, air, etc., can be absorbed or expelled.

[0010] According to the invention, an anti-adhesion sheet is a sheet that prevents adhesion.

[0011] According to the invention, a stack of air-permeable mesh layers is a stack of layers of porous material that allow air to flow away from the product being pressed, for example towards the vacuum port.

[0012] According to the invention, a prepreg or a layer of prepregs is a laminated composite material formed using a sheet of fibres impregnated with a resin that has not yet fully cured. The sheet of fibres is generally made of glass fibres, carbon fibres or polyaramid (Kevlar) fibres. The prepreg can be in the form of a stack of sheets.

[0013] The inventors found that a lack of compaction on some parts of the product (e.g. a stack of plies or prepreg plies) leads to the presence of voids between the plies after the curing process. The inventors also found that this lack of compaction is due to an uneven distribution of the vacuum pressure inside the vacuum press apparatus. The second porous anti-adhesion sheet allows air to flow inside the mat and provides a non-adhesion surface to the stack. The inventors also found that the structure of the vacuum distribution mat as described in the present application allows the vacuum pressure to be evenly distributed on the surface of the first element. Therefore, the compaction of the stack of plies is improved and the risk of voids is reduced. Therefore, the vacuum press apparatus as described in the present application can be suitable for de-bubbling the prepreg plies, for example, before the curing process.

[0014] Furthermore, the vacuum mat of the present application does not need to be changed between multiple applications, but can be reused multiple times. This allows to reduce the ecological footprint while allowing to benefit in terms of energy and material resources by, for example, reducing the manufacturing or maintenance of the prepreg plies or stack.

[0015] Some additional optional features of the vacuum apparatus according to the present application, which can be used together or separately, are listed below: - the stack of air-permeable mesh layers comprises at least two layers; - the first and second anti-adhesion sheets are made of PTFE; - the peripheral edges of the first and second porous anti-adhesion sheets are connected together by a flexible band; - the flexible band is made of PTFE; - the first element forms an angle with the horizontal plane comprised between 0° and 90°; - the support comprises at least one vacuum port, the at least one vacuum port being provided on at least one side of the support and communicating with the vacuum ports on the first element; - the vacuum press apparatus comprises a plurality of vacuum sources and / or a plurality of vacuum ports, the vacuum ports being evenly distributed on the first element and / or evenly distributed on at least one side of the support; - the support is a worktable; - the first element is a plate; - the lid is a plate; The present application also relates to a system comprising: - a vacuum press apparatus as described in the present application; and - a prepreg ply or a stack of plies, the prepreg ply or the stack of plies being clamped between the upper surface of the second porous anti-adhesion sheet and the lower surface of the lid.

[0016] The present application also relates to a method for compacting a prepreg ply or a stack of plies, the method comprising at least the following steps: - Positioning the prepreg layer or stack in a vacuum pressing apparatus as described in this application, the prepreg layer or stack being sandwiched between the upper surface of the second porous anti-adhesion sheet and the lower surface of the cap; and - Actuate a vacuum source to compact the prepreg layer or stack.

[0017] Some additional optional features of the method according to the invention, which can be used together or separately, are set forth below: a) In a vacuum pressing device, the prepreg layer or stack is positioned on a vacuum pad; b) Compact the prepreg layer or stack; c) Remove the compacted prepreg layer or stack from the vacuum pad; d) In a vacuum pressing apparatus, another layer or stack of prepreg is positioned on top of the vacuum pad; e) Repeat steps b), c), and d). Attached Figure Description

[0018] The invention will be described in more detail with reference to the following drawings, in which: - Figure 1 This is a perspective view showing an example of a vacuum pressing device according to the prior art; - Figure 2 Based on existing technology Figure 1 Another perspective view of the vacuum pressing equipment; - Figure 3 This is a perspective view illustrating an example of a vacuum pressing apparatus according to the present invention; - Figure 4 This is a schematic diagram of the vacuum distribution pad according to the present invention. - Figure 5 yes Figure 3 A schematic cross-sectional view of a portion of a vacuum pressing device, wherein the product is positioned within the vacuum pressing device; and - Figure 6 This is a schematic diagram of a method for compacting a product according to the present invention. Detailed Implementation

[0019] refer to Figure 1 Now, an example of a vacuum pressing device 100 as found in the prior art will be described. The vacuum pressing device 100 is, for example, a defoaming workbench or any device that requires applying a vacuum to a surface, but is not intended to be limiting.

[0020] The vacuum pressing apparatus 100 includes a support 102. In this example, the support 102 is a worktable, as shown in other figures of this application illustrating the vacuum pressing apparatus 100 ( Figures 1-5 That is, but not as a limitation.

[0021] The support member 102 may include at least a base 103 and legs 122 fixed to the base 103. The support member 102 may also include a first element 104, which is generally horizontal and fixed to the top of the base 103. The first element 104 includes an upper surface S. 101 upper surface S 101 Stacks configured to carry at least one or more product layers, such as stacks of prepreg layers formed of composite materials, but not as a limitation.

[0022] The vacuum pressing device may also include a cover 106. The cover may be part of the support 102 and is therefore considered a second element of the support 102. The cover 106 may be movable between a first position P0 and a second position P1, in which the cover 106 is applied to the first element 104 and in the second position P1, the cover 106 is away from the first element 104. Figure 1 A vacuum pressing device is shown, wherein the cover 106 is in the second position P1. The case where the cover 106 is in the first position P0 is, for example, in... Figure 2 As shown in the image.

[0023] The cover 106 is fixed or mounted at one end of the base 103. More precisely, the cover 106 is pivotally fixed or mounted relative to the base 103 or the first element 104. Figure 1 or Figure 2 As shown, the support member 102 may include a pivot axis A, which is parallel to the joint between the base 103 and the cover 106 of the support member 102. The cover 106 includes a lower surface S. 102 lower surface S 102 Facing the upper surface S of the first element 104 101 .

[0024] In some embodiments, the vacuum pressing device may include a metal plate or silicone film disposed on top of a first element 104 of the support 102.

[0025] Still referencing Figure 1 The vacuum pressing device 100 may further include a vacuum source 110, which includes at least a conduit 112 for connecting the vacuum source 110 to the support member 102. The vacuum source 110 is configured to apply vacuum pressure to the upper surface of the first element 104 facing the cover 106. For this purpose, the first element 104 may include a vacuum port 108 to which the end of the conduit 112 of the vacuum source 110 may be connected.

[0026] The support member 102 may also include a third element 116, which is disposed below the first element 104 and configured to receive the vacuum source 110. The third element may be a plate. The third element 116 is fixed to or associated with the leg 122 of the support member 102.

[0027] The vacuum device 100 also includes a control unit 114, which can be connected to the vacuum source 110. The control unit 114 is configured to actuate a vacuum between the first element and the cover when the cover is in its second position P1, i.e., when the cover is away from the first element 104.

[0028] Therefore, vacuum source 110 is used to apply a vacuum to the stack or product 1 by evacuating air from the packaged stack or product.

[0029] When vacuum pressure has been applied, the cover moves from the second position P1 to the first position P0 to compact the stack of products or layers.

[0030] In some embodiments, the vacuum pressing device 100 may further include a vacuum bag 2 (see Figure 4 For example, a silicone film, but not as a limitation, the vacuum bag 2 is configured to be placed on top of the product 1 or a stack of multiple product layers before vacuum pressure is applied.

[0031] Vacuum pressing equipment 100 may also include flexible sealant material 3 (see Figure 4 Flexible sealant material 3 is used to seal vacuum bag 2 to support member 102 or a tool on which product 1 or layer stacks can be set.

[0032] refer to Figure 3 The present invention describes a vacuum pressing apparatus according to the present invention. The vacuum pressing apparatus 100 of the present invention includes at least all the features mentioned above.

[0033] Therefore, the vacuum pressing device 100 includes at least: a support 102, which may be, for example, a workbench, but is not a limitation, and the support 102 includes a base 103 and legs 122 fixed to the base 103.

[0034] The support 102 includes: a first element 104, which is positioned or mounted on top of the base 103; and a cover 106, which is pivotally mounted relative to the base 103 or the first element 104 about a rotation axis A and moves between a first position P0 and a second position P1, in which the cover 106 is applied to the first element 104 and in which the cover 106 is away from the first element 104 at the second position P1.

[0035] The first element 102 forms an angle between 0° and 90° with respect to the horizontal plane. Preferably, the first element is horizontal, that is, parallel to the horizontal plane.

[0036] In one variation, the angle is preferably between 0° and 45°, and more preferably 30°.

[0037] Depending on the desired shape of the structure resulting from the product to be compacted or the stack, the first element can also be flat, or it can have a curved or complex shape. For example, but not as a limitation, the structure can be a ring-shaped component, such as the carter of an aircraft. In this example, the first element can be flat or curved.

[0038] The support 100 may further include a third element 116, which is fixed to or associated with the leg 122 and disposed below the first element 104 and configured to receive at least one vacuum source 110. Preferably, the third element is a plate. At least one vacuum source is connected to at least one vacuum port of the support 102.

[0039] At least one vacuum port 108 is provided on the first element.

[0040] The support may also include at least one vacuum port, which is disposed on at least one side of the support and communicates with a vacuum port disposed on the first element 104.

[0041] The vacuum pressing device 100 may further include: a control unit 114 connected to a vacuum source 110 and configured to actuate a vacuum between a first element 104 and a cover 106 when the cover 106 is in its second position P1; a vacuum bag 2 for covering the product to be compacted; and a flexible sealant material 3 for sealing the bag 2.

[0042] In some embodiments, the vacuum pressing device 100 may include a plurality of vacuum sources and / or a plurality of vacuum ports. The vacuum ports may be uniformly distributed on the first element 104 and / or uniformly distributed on at least one side of the support to improve the compaction of the product.

[0043] In another embodiment (not shown), the support 102 includes the features mentioned above, wherein the base 103 includes a housing configured to secure or mount the first element. In this case, the first element 104 may also be configured to be mounted or secured within the housing provided by the base 103 via interlocking. Thus, depending on the application and the shape type of the product or stack, a suitable first element (having a flat, curved, or complex shape) can be selected and secured or mounted on the base 103.

[0044] Therefore, those skilled in the art will understand that the vacuum pressing device 100 may be in the form of a kit that includes at least the features mentioned above.

[0045] In addition to the features described above, the vacuum pressing device of the present invention also includes a vacuum distribution pad 120, which is placed on the first element 104.

[0046] like Figure 4 As shown, the vacuum dispensing pad 120 has a parallelepiped shape. The vacuum dispensing pad 120 includes a first porous anti-adhesion sheet having a peripheral edge PE1. The peripheral edge PE1 includes two short sides and two long sides (compared to the short sides). The first porous sheet can be made of, for example, polytetrafluoroethylene (PTFE), but is not a limitation. The thickness of the first porous sheet is between 20 μm and 30 μm, preferably 25 μm.

[0047] The first porous anti-adhesion sheet 2001 includes a lower surface S 201 lower surface S 201 The application of S to the upper surface of the first element 104 101 It covers the opening of at least one vacuum port.

[0048] The vacuum distribution pad 120 also includes a stack 204 of breathable mesh layers disposed on top of the first porous sheet 2001. The stack 204 of breathable mesh layers comprises at least two layers. Figure 4 In the example shown, the stack of layers consists of two layers 204.

[0049] In some embodiments, the stack 204 of the breathable mesh may include multiple layers. As mentioned above, the breathable mesh is a porous material that allows air to flow away from the compressed product and toward the vacuum port. This material can be natural fibers, metal mesh, or any other matrix that allows fluid to flow through without resistance. Preferably, each breathable mesh has a thickness of approximately 25 μm.

[0050] In some embodiments, the number of breathable mesh layers may be increased to improve the vacuum pressure distribution in the vacuum pressing device 100. Therefore, the vacuum distribution pad 120 may include more than two breathable mesh layers 204.

[0051] The vacuum distribution pad 120 also includes a second porous anti-adhesion sheet 2002, which is disposed on top of the stack 204 of the breathable mesh layers. Similar to the first porous sheet 2001, the second anti-adhesion porous sheet also has a peripheral edge PE2. The thickness of the second porous sheet is between 20 μm and 30 μm, preferably 25 μm.

[0052] The second porous anti-adhesion sheet 2002 includes an upper surface S 202upper surface S 202 When the cover 106 is in its second position P1, the lower surface S of the cover 106 facing the support 102 102 The upper surface S of the second porous anti-adhesion sheet 2002 202 The lower surface S of the cover 102 102 Suitable for sandwiching stacks of products to be compacted, such as prepreg layers. The second porous sheet 2002 may also be made of, for example, PTFE, but is not a limitation.

[0053] The outer edges PE1 of the first porous sheet 2001 and the outer edges PE2 of the second porous sheet 2002 are connected to each other to embed the stack 204 of layers between the first porous anti-adhesion sheet 2001 and the second porous anti-adhesion sheet 2002.

[0054] The outer edge PE1 of the first anti-adhesion sheet 2001 and the outer edge PE2 of the second anti-adhesion sheet 2002 can be connected by a belt 202. Preferably, the belt is flexible, allowing the vacuum dispensing pad 120 to expand and contract during product compaction.

[0055] The strip 202 may also include an anti-adhesion surface. Similar to the first porous sheet 2001 and the second porous sheet 2002, the strip 202 may also be made of, for example, PTFE, but this is not a limitation.

[0056] Figure 5 An example of product 1 being placed in a vacuum apparatus 100 is shown. Product 1 is positioned on a vacuum dispensing pad 120 before compaction. In this example, a vacuum bag 2 is used to cover product 1, and the vacuum bag is sealed to a first element 104, which in this example is a plate, by a sealant material or a strip 3. The inner surface S of the vacuum bag 2... vb and the outer surface S of the first element 101 A defined volume V0, which includes the air that must be exhausted through the vacuum port 108 of the first element 2001 by means of a vacuum source 110. Figure 4 Airflow F in the middle.

[0057] The weight of the product constrains the second porous anti-adhesion sheet 2002, which in turn constrains the stacking of the breathable mesh layers 204. The constraint imposed by the weight of the product on the surface S of the second porous anti-adhesion sheet 2002... 202 The pressure is evenly distributed on the surface. Therefore, when air is discharged from volume V0 through vacuum port 108, the vacuum pressure P generated by the air discharge will be evenly applied to the inner surface S facing the vacuum bag 2. vb On the upper surface S0 of the product.

[0058] Airflow F passes through the porous second sheet 2002. Due to the uniformly applied constraint, airflow F is uniformly discharged through the vacuum distribution pad 120 by means of the breathable mesh layer 204. Since the first porous anti-adhesion sheet 2001 is also porous, airflow F is uniformly distributed onto the surface portion of the first element on which the vacuum pad is placed. In other words, the pressure is uniformly or equally distributed on the surface of the first element 104.

[0059] The vacuum pad can be configured to support a maximum vacuum pressure of approximately 1 bar, preferably 1 bar.

[0060] Advantageously, it should be understood that when the product is a stack of layers (e.g., a stack of prepreg layers), the vacuum pressure on the stack will uniformly expel the air located between the layers, so that after compaction, no air will remain trapped in the areas between the layers. Therefore, the vacuum pressing device 100 as described in this application is used to improve the compaction of the product.

[0061] For example, better compacted prepreg layers or stacks have a smaller chance of air being trapped between layers before the curing process. This will therefore prevent the cured material from having voids or pores. Thus, advantageously, the vacuum pressing device 100 also prevents defects, such as those mentioned above, from occurring after the curing process.

[0062] Furthermore, due to the surface S of the second porous sheet 2002 202 It is non-adhesive, so the resin will not adhere to the vacuum dispensing pad 120. Therefore, it should be understood that the vacuum dispensing pad 120, as described in this application, can be reused multiple times. This means that the vacuum pressing device 100 of this invention has the advantage of reducing the ecological footprint, while allowing for gains in energy and material resources by, for example, reducing the manufacturing or maintenance of prepreg layers or stacks.

[0063] In practice, the maintenance of equipment (e.g., turbines) or equipment parts made from products, prepreg layers, or stacks compacted using the vacuum pressing equipment described in this application is improved. Therefore, compaction as described reduces the risk of defects and thus reduces the maintenance of the equipment or equipment parts.

[0064] refer to Figure 6 The present invention also includes a method for compacting a prepreg layer or stack using a vacuum pressing device as described in this application.

[0065] The method includes at least step 400 of positioning a prepreg layer or stack in a vacuum pressing apparatus. The prepreg layer or stack 1 is disposed on a vacuum dispensing pad, more specifically, on top of the upper surface of a second porous anti-adhesion sheet 2002. As mentioned above, the prepreg layer or stack is covered by a vacuum bag 2 and sealed to a first element by a sealing strip 3, such as... Figure 4 As shown. The prepreg layer or stack 1 covered by bag 2 is sandwiched between the upper surface of the second porous anti-adhesion sheet 2002 and the lower surface S of the cover 106 of the support 102. 102 between.

[0066] The method also includes actuating the vacuum source 110 using a control unit 114 connected to the vacuum source 110 to compact the prepreg layer or stack. In this stage, after actuating the vacuum source and applying vacuum pressure, the cap moves from a second position P1 to a first position P0 to compact the stack of product or layers.

[0067] In some embodiments, the method may further include at least the following steps: a) In a vacuum pressing device, the prepreg layer or stack is positioned on a vacuum distribution pad; b) Compact the prepreg layer or stack; c) Remove the compacted prepreg layer or stack from the vacuum pad; d) In a vacuum pressing apparatus, another layer or stack of prepreg is positioned on top of the vacuum dispensing pad; e) Repeat steps b), c), and d).

[0068] The vacuum pad can be removed from the first element 104 or kept in place on the first element 104 between multiple applications.

Claims

1. A vacuum pressing device (100), said vacuum pressing device (100) comprising at least: - Support member (102), the support member having a first element (104); - A cover (106) movable between a first position (P1) and a second position (P2), in the first position the cover is away from the first element (104) and in the second position the cover is applied to the surface (104); - At least one vacuum source (110), said at least one vacuum source being connected to at least one vacuum port (108) of the first element (104); and - Control unit (114), the control unit being connected to the at least one vacuum source (110) and configured to actuate a vacuum between the first element (104) and the cover (106) when the cover (106) is in its second position (P2); The vacuum pressing device (100) further includes: - Vacuum dispensing pad (120), said vacuum dispensing pad comprising at least: • A first porous anti-adhesion sheet (2001) having a peripheral edge (PE1). • A stack of breathable mesh layers (204), the stack of breathable mesh layers being disposed on top of the first porous sheet (2001); and • A second porous anti-adhesion sheet (2002) is disposed on top of the stack (204) of the breathable mesh layers; the second porous anti-adhesion sheet (2002) has a peripheral edge (PE2); and The outer edges of the first porous anti-adhesion sheet and the second porous anti-adhesion sheet (2001, 2002) are connected to each other to embed the stack (204) of the layers between the first porous anti-adhesion sheet and the second porous anti-adhesion sheet (2001, 2002); The vacuum distribution pad (120) is laid on the first element (104) such that: - The first porous anti-adhesion sheet (2001) includes a lower surface (S 201 The lower surface is applied to the upper surface (S) of the first element (104). 101 ) and covering the opening of the at least one vacuum port (108), and - The second porous anti-adhesion sheet (2002) includes an upper surface (S 202 The upper surface faces the lower surface (S) of the cover (106) when the cover (106) is in its second position (P2). 102 ), the upper surface (S) of the second porous anti-adhesion sheet (2002) 202 ) and the lower surface (S) of the cover (106). 102 It is suitable for sandwiching the product to be compacted (1) between the two.

2. The vacuum pressing device (100) according to claim 1, wherein, The stack (204) of the breathable mesh layer comprises at least two layers.

3. The vacuum pressing device (100) according to claim 1 or 2, wherein, The first and second anti-adhesion sheets (2001, 2002) are made of PTFE.

4. The vacuum pressing device (100) according to any one of claims 1 to 3, wherein, The outer edges (PE1, PE2) of the first porous anti-adhesion sheet and the second porous anti-adhesion sheet (2001, 2002) are connected together by a flexible strip (202).

5. The vacuum pressing device according to claim 4, wherein, The flexible strip (202) is made of PTFE.

6. The vacuum pressing apparatus according to any one of claims 1 to 5, wherein, The first element (102) forms an angle between 0° and 90° relative to the horizontal plane.

7. The vacuum pressing apparatus according to any one of claims 1 to 6, wherein, The support (102) includes at least one vacuum port (108), which is disposed on at least one side of the support (102) and communicates with the vacuum port (108) on the first element (104).

8. The vacuum pressing apparatus according to any one of claims 1 to 7, wherein, The vacuum pressing device includes a plurality of vacuum sources (110) and / or a plurality of vacuum ports (108), the vacuum ports (108) being uniformly distributed on the first element (104) and / or uniformly distributed on at least one side of the support (102).

9. A system comprising at least: - Vacuum pressing apparatus (100) according to any one of claims 1 to 5; and - A prepreg layer or stack, said prepreg layer or stack being sandwiched on the upper surface (S) of the second porous anti-adhesion sheet (2002). 202 ) and the lower surface (S) of the cover (106). 102 )between.

10. A method (300) for compacting a prepreg layer or stack, the method comprising at least the following steps: - Positioning (400) the prepreg layer or stack in a vacuum pressing apparatus (100) according to any one of claims 1 to 5, wherein the prepreg layer or stack is clamped on the upper surface (S) of the second porous anti-adhesion sheet (2002). 202 ) and the lower surface (S) of the cover (106). 102 Between; and - Actuate (402) the vacuum source (110) to compact the prepreg layer or stack.

11. The method (300) according to the preceding claim further comprises at least the following steps: a) In the vacuum pressing apparatus (100), the prepreg layer or stack is positioned on the vacuum distribution pad (120); b) Compact the prepreg layer or stack; c) Remove the compacted prepreg layer or stack from the vacuum pad (120); d) In the vacuum pressing device (100), another prepreg layer or stack is positioned on top of the vacuum distribution pad (120); e) Repeat steps b), c), and d).

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