Multi-layer pre-assembled cover member

Abstract

The invention relates to a multi-layered covering element (2) for covering a component chamber in a mold for producing a fiber composite component. The invention proposes that the covering element (2) is constructed as a multi-layered preassembled material sheet, that a suction chamber (8) of the covering element (2) is closed at its peripheral edge (12) by the membrane (4) in connection with the film (6) at least in a matrix material-tight manner, that the film (6) has an opening (14) which is adapted to allow gas flowing into the suction chamber (8) to escape in a direction away from the component chamber, that a lying element (16) which delimits the opening (14) is arranged on a side of the film (6) facing away from the suction chamber (8), that the lying element is connected to the film (6) at least in a matrix material-tight manner, and that the lying element has a lying surface (18) on a side of the lying element facing away from the film (6), the covering element (2) being placeable on the inside of a mold wall (22) delimiting the component chamber by means of the lying surface.

Description

Technical Field

[0001] The present invention relates to a multilayer covering member for covering a component cavity in a mold for manufacturing fiber composite components and a method for sealing a vent in a mold for manufacturing fiber composite components, the covering member having a permeable but impermeable membrane and an impermeable and impermeable membrane, the membrane and the membrane defining a suction chamber therebetween for venting gas entering the suction chamber from the component cavity through the membrane, and the covering member having a flow aid disposed in the suction chamber between the membrane and the membrane. Background Technology

[0002] As known from the public case DE 10 2017 130 201 A1, a component chamber is manufactured in a mold for manufacturing a fiber composite component by means of a cover member of the same type, wherein the layers of the cover member are successively placed on an open mold.

[0003] As known from public case DE 10 2019 115 447 A1, a composite mold is used, the components of which define a cavity on the periphery. The mold has vents through which gas is drawn from the cavity and the injected matrix material.

[0004] One problem lies in sealing the vents to prevent the matrix material from escaping. It is difficult to align known multilayers in the mold so that gas in the component chamber can also be expelled through the vents. A membrane must be opened in the appropriate position and sealed towards the vent. If the seal is imperfect, the vent will become blocked, resulting in a defective fiber composite component that must be discarded as scrap. If the matrix material enters the vent, it will become blocked, and gas can no longer be drawn out of the cavity.

[0005] Another problem is that the vent can only draw gas out of the matrix material in the exit area of ​​that vent. Larger areas cannot be drawn out using this mold. Although the component chamber can be covered sequentially with multiple layers of covering components in a known manner, this type of covering requires a significant amount of manual work and material consumption. Summary of the Invention

[0006] The object of this invention is to provide a solution by which vents in composite molds used for manufacturing fiber composite components can be easily sealed against penetrating matrix material. Furthermore, a solution should also be found on how to enhance the suction effect of the vents within the surface.

[0007] With respect to similar cover members, the solution of the present invention to achieve the above-mentioned objective is that the cover member is constructed as a multi-layered pre-assembled material sheet, the suction chamber of the cover member is closed at its peripheral edge by the connection of the sheet to the film with at least an impermeable matrix material, the film having an opening adapted to allow gas flowing into the suction chamber to escape in a direction away from the component chamber, and an abutment element defining the opening is arranged on the side of the film opposite to the suction chamber, the abutment element being connected to the film with at least an impermeable matrix material, and the abutment element having an abutment surface on its side opposite to the film, the cover member being able to be placed on the inside of the mold wall defining the component chamber by means of the abutment surface.

[0008] In terms of similar methods, the solution of the present invention to achieve the above-mentioned objective is to use the covering member to seal against the penetrating matrix material.

[0009] The cover component, constructed as a pre-assembled sheet of material, can be placed as a single part on the inner side of the mold wall along with the abutment element in the vent area. A diaphragm separates the suction chamber within the cover component from the liquid matrix material introduced into the component cavity. A thin film seals this suction chamber against the matrix material on the side opposite the diaphragm in an airtight and impermeable manner.

[0010] Instead of a thin film, a membrane that is at least impermeable to the matrix material can be used in this location, but it is less expensive and does not have to bear any technical disadvantages. In typical applications, the thin film is attached to the inner side of the mold wall with its outer side against it, so there is no matrix material or only a small amount of matrix material present in this location.

[0011] The membrane and film, connected at least at their edges in a manner impermeable to the matrix material, thus define a suction chamber sealed against the matrix material, through which gas can be drawn from the component chamber through the membrane. A flow aid is embedded in the suction chamber to prevent the film from lying flat on the membrane, which would cause the suction chamber to collapse and prevent gas from flowing through it. This flow aid is, for example, made of a fibrous material (such as a fiber web or knitted fabric) through which gas can still flow, and which maintains a certain distance between the membrane and film even under a vacuum applied at the mold.

[0012] The cover member has an opening in the membrane, through which gas drawn into the suction chamber can flow out of the cover member toward the vent. The cover member keeps the matrix material away from the vent via the membrane, but gas drawn from the component chamber can freely flow from the suction chamber into the vent through this opening, thus passing through the cover member and being drawn out of the component chamber.

[0013] The cover member is sealed relative to the inner side of the mold wall by an abutment element, which is an integral part of the cover member. This abutment element is placed against the inner side of the mold wall with its side facing away from the cover member, specifically positioned in a way that allows gas drawn from the component chamber into the suction chamber of the cover member to flow through this opening into the mold's vent. The abutment element forms a flange and reinforcement for the film in the area of ​​the opening. The abutment element can be shaped to fit into the wall of the vent in a form-fitting manner. The abutment element can be held in place, for example, by retaining a connector, clip, etc. However, the cover member can also be held in place by the negative pressure in the vent area using the abutment surface of the abutment element, or by using other fixing aids, such as adhesives, which facilitate adhesion between the abutment surface and the inner side of the mold wall.

[0014] Because the contact element is connected to the membrane in a manner that is at least impermeable to the substrate material, the substrate material located in the component chamber and / or substrate material cannot enter the vent through the transition area between the membrane and the contact element. If this connection is both impermeable to the substrate material and airtight, gas cannot flow through the connection area. Thus, the vacuum only acts on the diaphragm, and gas only enters the suction chamber and vent through this diaphragm. Of course, the connection between the contact surface of the contact element and the inner side of the mold wall is also implemented in a manner that is at least impermeable to the substrate material.

[0015] The vents of a composite mold used for manufacturing fiber composite components can be sealed in a simple manner against the penetrating matrix material using the covering member according to the invention, specifically by placing the covering member only onto the inlet from the component chamber side. It is no longer necessary to embed the individual layers of the covering into the component chamber in the vent area. These layers are already connected and sealed to form the finished covering member; therefore, only a single covering member needs to be installed in the vent outlet area. Subsequent sealing work is eliminated.

[0016] If the cover member is connected to the vent, gas can be drawn from the module chamber over the entire area of ​​the diaphragm. In a preferred embodiment of the cover member, the area of ​​the diaphragm is larger than the cross-sectional area of ​​the vent, thus allowing for suction over a larger area compared to the case where gas is drawn out only through the vent.

[0017] According to one embodiment of the present invention, the abutment surface is provided with an adhesive layer, which allows the cover member to be fixed to the inner side of the mold wall defining the component chamber. If the abutment surface is provided with an adhesive layer, pressing the cover member against the inner side of the mold wall using the abutment surface is sufficient to install and fix the cover member to the mold wall. In this case, the cover member is securely installed in its target position without requiring additional work.

[0018] According to one embodiment of the present invention, the adhesive layer is provided with an outwardly non-adhesive release film. This release film protects the adhesive layer from undesirable adhesion to other objects before intended use.

[0019] According to one aspect of the invention, the adhesive layer and the abutment surface are adapted to abut against the inner side of a mold wall defining a component chamber, at least in a manner impermeable to the matrix material. The shape, size, and surface characteristics of this abutment surface must be constructed in such a way that, in the appropriate application, the matrix material cannot enter the vent area through the connection zone between the abutment element and the mold wall. The adhesive used in the adhesive layer is designed such that it will not be dissolved by the matrix material during the infusion and solidification stages of the matrix material and that it safely holds the cover member in the installed position.

[0020] According to one aspect of the invention, the opening is circular and the abutment element surrounds the opening by means of a similarly circular abutment surface. These circular shapes match the typically circular shape of vents. Minor dimensional differences can be compensated for by the larger size of the abutment surface of the abutment element, allowing the cover member to fit vents of different sizes.

[0021] According to one aspect of the invention, the abutment surface has a width in the radial direction from the center of the opening, which is at least one-quarter of the diameter of the opening. This width of the abutment surface allows the covering member to be placed on vents of different sizes. However, within this range of abutment surface widths, larger surrounding abutment surfaces can also compensate for point irregularities and contamination present in the connection area that may cause leaks in the connection.

[0022] According to one embodiment of the present invention, the diaphragm and the thin film are thermally welded together at their outer edges. As a connection, welding can be achieved in a low-cost, fast, and reliable manner.

[0023] According to one embodiment of the present invention, the abutment element is made of butyl rubber with a closed abutment surface. Butyl rubber is elastic, effectively absorbs vibration and impact energy, and has good acid and alkali resistance. The butyl rubber deforms under pressure, thereby optimally matching the contour of the area surrounding the vent. In this way, the abutment element can flexibly adapt to the corresponding shape of the inner side of the mold wall defining the component chamber and reliably be placed in a sealed manner on the inner side of this mold wall.

[0024] According to one embodiment of the present invention, the planar area of ​​the covering member is more than five times the cross-sectional area of ​​the opening. With this size ratio, there is a good relationship between the suction effect of the covering member and the discharge of the suctioned gas through the vent.

[0025] Other features of the invention are described in the claims, drawings, and objective description. All features and combinations thereof mentioned in the specification, as well as features and combinations thereof mentioned in the following description of the drawings and / or shown separately in the drawings, may be used not only in the specified combinations, but also in other combinations or individually. Attached Figure Description

[0026] Combining preferred embodiments and Figure 1 The present invention will be described in detail below. Detailed Implementation

[0027] Figure 1 A cross-section of a cover member 2 located in the component chamber 26 of the mold is shown. The cover member 2 has a diaphragm 4 on one side and a thin film 6 on the other side. The diaphragm 4 and the thin film 6 define a suction chamber 8 through which gas drawn from the component chamber 26 flows toward the opening 14. To prevent matrix material from penetrating into the suction chamber 8, the diaphragm 4 and the thin film 6 are connected to each other, at least in a matrix-impermeable manner, in the region of the edge 12.

[0028] On the side of the cover member 2 facing away from the component chamber 26, in the area of ​​the opening 14, the abutment element 16 is placed on the outer side of the film 6. The cover member 2 can be placed on the inner side 24 of the mold wall 22 in the area of ​​the vent 32 by means of the abutment surface 18 constructed on the abutment element 16. In order to improve the adhesion of the cover member 2 to the mold wall 22, an adhesive layer 20 can be arranged on the abutment surface 18, through which the cover member 2 is bonded to the mold wall 22.

[0029] In the appendix Figure 1At this stage, the cover member 2 is not yet fixed to the mold wall 22. To fix the cover member 2 to the mold wall 22, it must be pressed against the mold wall within the contact surface 18 along the directions of the two arrows. Then, the cover member is connected to the inner side 24 of the mold wall 22, at least in a manner impermeable to the substrate material. Figure 1 As can be seen, the diameters of opening 14 and vent 32 are not exactly the same. However, this dimensional difference is compensated by the width of the contact surface 18, so a covering member with opening 14, whose diameter is smaller than that of vent 32, can still be used to seal such a vent.

[0030] exist Figure 1 In the illustrated embodiment, the mold consists of a first component 28 defining the lower portion of the component chamber 26 and a second component 30 covering the component chamber 26 upwards. Preferably, the fiber layer reinforcing the finished component is embedded in the first component 28 before the component chamber 26 is closed and filled with matrix material, for example, by means of vacuum infusion. The component chamber 26 is closed when the components 28 and 30 are stacked on top of each other. After the mold is closed, the component chamber 26 is evacuated by applying a vacuum to the vent 32. For simplicity, the vacuum pump and its associated hoses and lines, as well as the storage tank and feed line for the matrix material, are not included. Figure 1 Shown in the middle.

[0031] Finally, it should be pointed out that, Figure 1 The cover member 2 and its components shown may deviate from the illustrated embodiment in terms of their size relative to the vent 32, their overall size relative to the mold, the size ratios between the individual components of the cover member 2, and the shape, layout, and size of the individual components.

[0032] This invention is not limited to the embodiments described above. It will not be difficult for those skilled in the art to modify the embodiments in ways they deem appropriate to adapt them to specific application examples.

[0033] Figure Labels

[0034] 2 Covering components

[0035] 4. Membrane

[0036] 6 films

[0037] 8 Suction Chamber

[0038] 10. Mobile auxiliary parts

[0039] 12 Edges

[0040] 14 Opening

[0041] 16 Attached components

[0042] 18. Surface against

[0043] 20 Adhesive layer

[0044] 22 Mold Wall

Claims

1. A multilayer covering member (2) for covering a component chamber in a mold for manufacturing a fiber composite component, the covering member having a permeable but matrix-impermeable membrane (4) and a non-permeable and matrix-impermeable film (6), the membrane and the film defining a suction chamber (8) therebetween for venting gas entering the suction chamber (8) from the component chamber through the membrane (4), and the covering member having a flow aid (10) disposed in the suction chamber (8) between the membrane (4) and the film (6), characterized in that, The covering member (2) is constructed as a multi-layered pre-assembled material sheet. The suction chamber (8) of the covering member (2) is closed at its peripheral edge (12) by the connection of the membrane (4) and the film (6) with at least an impermeable matrix material. The film (6) has an opening (14) adapted to allow gas flowing into the suction chamber (8) to escape in a direction away from the component chamber. A sticker defining the opening (14) is arranged on the side of the film (6) opposite to the suction chamber (8). The abutment element (16) is connected to the film (6) at least in a manner that is impermeable to the substrate material, and the abutment element has an abutment surface (18) on its side away from the film (6). The cover member (2) can be placed on the inside of the mold wall (22) that defines the component chamber by means of the abutment surface, the abutment surface (18) is provided with an adhesive layer (20), and the cover member (2) can be fixed on the inside of the mold wall (22) that defines the component chamber by means of the adhesive layer.

2. The covering member (2) according to claim 1, characterized in that, The adhesive layer (20) is provided with an outward-facing, non-adhesive release film.

3. The covering member (2) according to claim 1 or 2, characterized in that, The adhesive layer (20) and the abutment surface (18) are adapted to abut against the inner side of the mold wall (22) defining the component chamber, at least in a manner impermeable to the matrix material.

4. The covering member (2) according to claim 1, characterized in that, The opening (14) is circular and the abutting element (16) surrounds the opening (14) by means of an abutting surface (18) that is also circular.

5. The covering member (2) according to claim 4, characterized in that, The contact surface (18) has a width in the radial direction from the center of the opening (14), the width being at least one-quarter of the diameter of the opening (14).

6. The covering member (2) according to claim 1, characterized in that, The diaphragm (4) and the thin film (6) are thermally welded together at the edge (12).

7. The covering member (2) according to claim 1, characterized in that, The abutting element (16) is made of butyl rubber with a closed abutting surface (18).

8. The covering member (2) according to claim 1, characterized in that, The planar area of ​​the covering member (2) is more than five times the cross-sectional area of ​​the opening (14).

9. A method for sealing vents in a mold used for manufacturing fiber composite components, characterized in that, The covering member according to claim 1 is used to seal against the penetrating matrix material.

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