Method and facility for manufacturing a vacuum-moulded part

Abstract

A method for manufacturing a part comprises the following steps: - providing a moulding element (100) and an airtight flexible sheet (200) consisting of a film comprising a dry coat (201) of a material of the paint type secured to a backing (202) provided with anchoring arrangements on the opposite side to the coat of material of the paint type, the backing facing towards the moulding element and the sheet being unsupported and peripherally connected to the rigid moulding element in an airtight manner so that they between them define a moulding zone the shape of which is generally defined by the moulding element, - introducing into the moulding zone a solidifiable moulding material in the viscous state, - prior to, simultaneously with or subsequent to said introduction of the moulding material, applying a vacuum (120-122) in the moulding zone, - causing the moulding material (R) to solidify, and - extracting from the moulding zone an article (P) comprising the solidified moulding material, in which the film is anchored, where the dry coat of material of the paint type that forms part of said film is exposed to the outside.

Description

[0001] Title: Method and installation for manufacturing a molded part with vacuum application

[0002] Field of invention

[0003] The present invention relates generally to the manufacture of molded parts.

[0004] State of the art

[0005] There are many techniques for producing volume parts by filling a molding area or cavity with a liquid or viscous material and then setting or hardening the material.

[0006] These may be parts injected with a thermoplastic or thermosetting material, infusion of resin into a mold where structural elements have been incorporated (in particular mineral fibers such as glass fabrics, etc.), molded concrete elements, etc.

[0007] In the particular case of an infusion type process, a resin is introduced into the molding cavity in which the structural elements have been placed, this cavity is exposed to a vacuum source at one or more points, so that the resin, from the supply point(s), spreads over the entire extent of the cavity.

[0008] For this purpose, a flexible sealing sheet ("vacuum bag" in English terminology) is used, applied above the structural elements and connected in a watertight manner to the mold around its entire periphery.

[0009] It is then necessary to remove this sealing sheet.

[0010] In the case where the raw appearance of the surface of the part on the sealing sheet side does not pose any difficulty, particularly in relation to the type of part produced (for example, the interior of a boat hull), it is left as is.

[0011] But in other cases, it is necessary to apply a finishing treatment (paint, gelcoat, etc.) to this raw surface, which requires an additional step in the manufacture of the part. Note that here the mold defines only one face of the part, the other face being defined at the level of the flexible sealing sheet. This excludes processes using two rigid mold parts close to each other and defining a closed molding space, as for example in document US2008206540A1.

[0012] Summary of the invention

[0013] The present invention aims to simplify the production of the part when it must, on its raw face corresponding to the side where the “vacuum bag” type sealing sheet is applied, present a certain appearance and / or a certain functionality.

[0014] For this purpose, a method of manufacturing a part is proposed, of the type comprising the following steps:

[0015] - providing a rigid molding element capable of conforming one face of the part and a flexible airtight sheet pre-constituted from a film comprising a dry layer of a paint-type material secured to a backing provided with anchoring arrangements on the side opposite the layer of paint-type material, the backing being turned towards the molding element, and said sheet being unsupported and being connected peripherally to the rigid molding element in an airtight manner so that they define between themselves a molding zone whose shape is generally defined by the molding element,

[0016] - bringing into the molding area a solidifiable molding material in a viscous state,

[0017] - prior to, simultaneously with or after said supply of the molding material, applying a vacuum in the molding zone,

[0018] - cause the casting material to solidify, and

[0019] - extracting from the molding area an article comprising the solidified molding material, in which the film is anchored, where the dry layer of paint-like material of said film is exposed to the outside.

[0020] Preferred but non-limiting aspects of this method include the following additional features: * the method also includes a step of placing in the molding zone, prior to supplying the molding material and applying the vacuum, a reinforcing material intended to be embedded in the molding material.

[0021] * the molding material consists of a resin, in particular an impregnable resin. Here, the term "resin" means any product, natural, artificial or synthetic, capable of hardening by polymerization under given conditions which differ according to the type of resin.

[0022] * resin supply is carried out by a process included in the following group: infusion, pre-impregnation, contact molding, resin transfer molding, filament winding.

[0023] * the film backing is a fibrous backing, with free or structured fibers, the anchoring arrangements comprising fibers projecting beyond the layer of paint-type material. These fibers may be of any nature, shape and size, provided that at least some of them have to anchor themselves in the molding material during its progression in the zone

[0024] * the molding element and the waterproof sheet extend beyond the contours of the part to be produced through marginal areas.

[0025] * the method comprises a step of peripheral cutting of the part to remove the material corresponding at least in part to said marginal zones.

[0026] * the vacuum source is connected to the molding zone by at least one vacuum outlet passing through said film.

[0027] * the method also comprises a step consisting, prior to the step of supplying the molding material, in placing against the molding element another film comprising a dry layer of a paint-type material secured to a backing provided with anchoring arrangements on the side opposite the layer of paint-type material, the backing being turned towards the airtight flexible sheet. * the film constituting the airtight flexible sheet and the other film are identical.

[0028] According to a second aspect, an installation is proposed for manufacturing a part with a molding material, comprising:

[0029] - a rigid molding element capable of shaping one face of the part,

[0030] - an airtight, unsupported flexible sheet connected peripherally to the rigid molding element in an airtight manner so that they define between themselves a molding zone whose shape is generally defined by the molding element,

[0031] - a vacuum source connected to the molding zone, so that a vacuum can be exerted in the molding zone during or after a supply of molding material into said zone, installation characterized in that the airtight flexible sheet is pre-constituted from a film comprising a dry layer of a paint-type material secured to a backing provided with anchoring arrangements on the side opposite the layer of paint-type material, the backing being turned towards the molding element and being capable of anchoring itself in the molding material as the latter spreads in the molding zone.

[0032] Preferred but not limited to aspects of this installation include the following additional features:

[0033] * the installation also includes a reinforcing material placed in the molding area and intended to be embedded in the molding material.

[0034] * the molding material consists of a resin, in particular an impregnable resin, or a thermoplastic polymer in the molten state.

[0035] * the resin supply is carried out by a process included in the following group: infusion, pre-impregnation, contact molding, resin transfer molding, filament winding. * the film backing is a fibrous backing, the anchoring arrangements comprising fibers extending beyond the layer of paint-type material.

[0036] * the molding element and the waterproof sheet extend beyond the contours of the part to be produced through marginal areas.

[0037] * the vacuum source is connected to the molding zone by at least one vacuum outlet passing through said film.

[0038] Finally, a use is proposed of a pre-constituted film of a dry layer of a paint-type material anchored in a backing provided with anchoring arrangements on the side opposite the layer of paint-type material, for its application against a face of a part opposite a mold element while being unsupported, in order to define between the film and the mold element, by themselves, a sealed molding space into which a molding material can be brought and into which a vacuum can be applied.

[0039] Brief description of the drawings

[0040] Other aspects, aims and advantages of the present invention will become more apparent upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example and with reference to the accompanying drawings, in which:

[0041] - Fig. 1 is a schematic top view of an installation for producing a part using a so-called infusion process according to the invention,

[0042] - Fig. 2 is a schematic longitudinal sectional view of the installation of Fig. 1,

[0043] - Fig. 3 is a schematic top view of the part produced, after cutting,

[0044] - Fig. 4 is a schematic longitudinal sectional view of the part of Fig. 3,

[0045] - Fig. 5 is an enlarged cross-sectional view of a sheet used in the installation of Figs. 1 and 2, and - Fig. 6 is an enlarged cross-sectional view of a portion of the produced part in which the sheet is anchored.

[0046] It should be noted that the vertical scales of the drawings do not necessarily reflect reality but have been adapted for a good understanding of the invention.

[0047] Detailed description of an embodiment

[0048] With reference to the Figures, a method for producing a volume part according to an exemplary embodiment of the invention will now be schematically described.

[0049] The installation firstly comprises a rigid mould 100 for the part comprising a mould base 101 defining the external shape of the part to be produced, a container or reservoir 110 containing a resin R intended to form the part, and a set of pipes 111 connecting the container 110 to a set of injection points 112 provided in a sealing sheet 200, which will be described in more detail below, unsupported and placed above the mould 100.

[0050] The term “unsupported” means that the sealing sheet is not backed by a rigid mold part that would be applied against the mold base 101 before the resin is supplied.

[0051] The injection points 112 each typically comprise a connector mounted in a sealed manner in the sealing sheet and capable of placing the corresponding end of the homologous pipe 111 in communication with a mold cavity jointly defined by the rigid mold 100 and the sealing sheet 200.

[0052] The installation further comprises a vacuum pump 120 connected by a vacuum line 121 to one or more vacuum application points 122. This vacuum application point is in communication with a peripheral zone 123 of the mold cavity, formed by a bead of an incompressible material permeable to air such as a draining felt, a draining mesh or a spiral pipe. This zone 123 is intended to distribute the application of the vacuum over the entire periphery of the molding cavity with a view to a homogeneous progression of the resin R during the infusion process.

[0053] Reference 130 designates a thick adhesive tape with high deformability intended to ensure sealing between the periphery of the sealing sheet 200 and the periphery of the mold 100, this tape being arranged outside the incompressible bead forming the zone 123.

[0054] The installation further comprises a core material 140 for the part to be produced, arranged between the bottom of the mold 100 and the sealing sheet 200. This material typically comprises one or more layers 141 of a reinforcing and / or stiffening material, such as superimposed layers of a fabric such as a glass fabric, carbon fabric, etc. It is also possible to advantageously provide one or more layers forming a drain, generally thicker and more openwork than the reinforcing material 140, intended in a manner known per se to facilitate the circulation of the resin to all areas of the part during the infusion process. The drainage means may also comprise a low-density foam constituting channels for the resin.

[0055] The part is produced by causing the resin R contained in the container 110 to penetrate into the mold cavity defined between the mold bottom 101 and the sealing sheet 200 and by spreading in the cavity in a manner favored by the application of the vacuum.

[0056] After solidification of the resin R, the various elements of the installation are removed, and the part P consisting of the resin R in which the core material 140 is embedded, as well as the sheet 200, is removed from the mold.

[0057] The part is then trimmed to eliminate its marginal parts (trimmed area 150 in Figs. 3 and 4), the face of the part on the mold side being designated by the reference 151.

[0058] According to one aspect of the invention, and with reference to Fig. 5, the sealing sheet 200 consists of a film comprising a part 201 comprising one or more dry layers of a paint-type material, secured to a backing 202 provided with anchoring arrangements on the side opposite the layer of paint-type material, the backing being turned towards the mold 100, and this film being, as mentioned, connected peripherally to the mold 100 in an airtight manner, using means similar to those used for a traditional “vacuum bag” type sealing sheet.

[0059] Here, the term "paint-type material" means an opaque (pigmented) or transparent or translucent (varnish) material which is normally applied in liquid or gel form, as opposed in particular to thin films of plastic, single-layer or laminated.

[0060] This film is produced for example in accordance with the teachings of document WO2016110799A1. If necessary, these sealing means (thickness, malleability, adhesion forces, etc.) are adapted to take into account the fact that the film 200 may have greater rigidity than that of a traditional sealing sheet, which is generally thinner and more flexible.

[0061] In this way, during the process, the film 200, thanks to the vacuum, is intimately applied against the resin being infused, and once the process is completed and the resin has set, the upper face of the part (side opposite the mold 100) comprises, in a manner closely linked to the structure of the part thanks to the backing, an integrated decorative and / or functional layer (case where the dry paint has particular properties). Thus, Fig. 6 illustrates the part P made of the resin R in which the core elements 140 are embedded and on the surface (opposite the mold) of which the film 200 is firmly anchored, the fibers of the backing 202 which initially overflowed relative to the part 201 of the film being at least partially trapped in the resin R. Thus, the film 200 acts as both a sealing sheet (“vacuum bag” in the manufacturing process) and a finishing layer for the part on the same face.This layer can have different functions: decoration, protection, but also functionalization of the surface of the part by integrating particular layers into the paint layer(s), as described for example in the various patents published in the name of the company Corso Magenta.

[0062] It will be noted that in the illustrated embodiment, the resin supply points 112 pass through the film 200 at locations located away from the periphery of the part.

[0063] These supply points may, in practice, be arranged either as illustrated, or on the periphery, or in a combination of such locations, the choice being dictated in particular by the shape and dimensions of the room.

[0064] In an alternative embodiment and in a manner not illustrated, it is also possible, prior to the step of supplying the molding material, to place against the mold 100 another film identical or similar to the film 200, in such a way that this additional film becomes anchored in the resin R on the opposite face of the part, thereby giving it a particular appearance and / or a particular functionality.

[0065] The invention, the basic principle of which has been described above, may have numerous variants and modifications.

[0066] Especially :

[0067] - the material 123 forming incompressible zones can also be provided over the extent of the part to form distribution channels both for the circulation of the resin and for the distribution of the vacuum; more generally, the arrangement of drains and such channels will be designed by a person skilled in the art according to the different constraints present (shape and dimensions of the part, viscosity of the resin, etc.) to optimize the progression of the resin front(s);

[0068] - The areas 152 of the part P corresponding to the locations of the resin injection points 112 can be subject, if necessary, after production of the part, to any special treatment such as additional painting;

[0069] - the sheet 200 at its backing 202 can be arranged to contribute to this function of controlling the resin front(s), by designing the backing in a particular way (thickness, density of material, shape and arrangement of the fibers, etc.).

[0070] - in the case where the size of the part to be manufactured is such that two or more strips of 200 film must be juxtaposed, it is necessary to ensure a seal between the homologous edges of two adjacent strips; different approaches can be considered, including overlapping the edges with the interposition of an adhesive.

[0071] We will now give a number of examples of materials and parameters that can be used in an infusion process as described above.

[0072] - type of infused resin: two-component resins such as epoxy, polyester, vinyl ester resins, possibly bio-sourced, thermosetting resins or even thermoplastic resins such as acrylic resins, in particular those marketed under the Elium® brand by the Arkema company;

[0073] - type of reinforcing material 300:

[0074] • in sheet or tablecloth: fabrics (taffeta, satin, twill, mesh, knitted, etc.), non-wovens,

[0075] • particles: fibers or grains of glass, carbon, aramid, Kevlar®, linen, with weights of around 20 to 600 g / m2,

[0076] - type of paint of the film 200 and range of thicknesses: two-component (epoxy or polyurethane) or single-component (acrylic, epoxy, polyurethane); thickness of the order of 30 to 120 pm; it should be noted here that in the case where the infusion process involves heating, or in the case where the setting of the resin generates heat, the nature of the paint and, where appropriate, its fibrous backing are chosen);

[0077] - type of fibrous backing of the film 200, density and thickness: fabric, mat or glass particles, carbon, aramid, Kevlar®, linen in various forms, with a weight of the order of 15 to 150 g / m2. More generally, it will be noted that the nature and thickness of the fibrous backing of the film are chosen in a manner adapted to the nature and viscosity of the resin. In particular, the texture, density and thickness of the free part of the backing 202 of the film 200 can be chosen in particular as a function of the viscosity and other properties of the resin when it comes into contact with the film, in particular so that this material fills this free part well and ensures effective anchoring. For example, a texture is provided that is all the more aerated as the resin is viscous.

[0078] Of course, the present invention is not limited to the embodiment described and illustrated in the drawings, but may be the subject of numerous variations and modifications.

[0079] In particular, the invention can be applied, in a non-limiting manner, in particular to any of the following processes: infusion, pre-impregnation, contact molding, transfer molding, based on resin or thermoplastic polymer in the molten state, filament winding, for manufacturing various parts and in particular parts of large dimensions in length and width compared to their thickness such as boat hulls, wind turbine propeller blades, etc.

Claims

Demands 1. A method for manufacturing a part, of the type comprising the following steps: - provide a rigid molding element (100) capable of conforming one face of the part and a pre-made, airtight, flexible sheet (200) comprising a dry layer (201) of a paint-type material attached to a backing (202) with anchoring features on the side opposite the paint-type material layer, the backing facing the molding element, and said sheet being unsupported and peripherally connected to the rigid molding element in an airtight manner (130) so that they define between themselves a molding zone whose shape is generally defined by the molding element, - to bring a solidifiable molding material (R) in a viscous state into the molding area, - prior to, simultaneously with, or subsequent to the aforementioned introduction of the molding material, apply a vacuum (120-122) in the molding zone, - to bring the molding material to solidify, and - extract from molding area an article (P) comprising the solidified molding material, in which the film (200) is anchored, where the dry layer of paint-like material (201) of said film is exposed to the outside.

2. Method according to claim 1, characterized in that it also includes a step of placing in the molding zone, prior to the introduction of the molding material and the application of the vacuum, a reinforcing material (140, 141) intended to be embedded in the molding material.

3. A method according to any one of claims 1 and 2, characterized in that the molding material (R) consists of a resin, in particular an impregnable resin.

4. A process according to claim 3, characterized in that the resin delivery is carried out by a process included in the following group: infusion, pre-impregnation, contact molding, resin transfer molding, filament winding.

5. A method according to any one of claims 1 to 4, characterized in that the backing (202) of the sheet is a fibrous backing, the anchoring arrangements comprising fibers extending beyond the layer of paint-type material.

6. A method according to any one of claims 1 to 5, characterized in that the molding element (100) and the sealing sheet (200) extend beyond the contours of the part to be produced by marginal areas.

7. A method according to claim 6, characterized in that it comprises a peripheral cutting step of the part to remove the material corresponding at least in part to said marginal areas.

8. A method according to any one of claims 1 to 7, characterized in that the vacuum source (120) is connected to the molding zone by at least one vacuum port (122) passing through said sheet.

9. A method according to any one of claims 1 to 8, characterized in that it also comprises a step consisting, prior to the step of feeding the molding material, of placing against the molding element (100) another sheet comprising a dry layer of a paint-like material attached to a backing having anchoring features on the side opposite the layer of paint-type material, the backrest is turned towards the flexible, airtight sheet.

10. Method according to claim 9, characterized in that the film (200) constituting the airtight flexible film and the other film are identical.

11. Installation for manufacturing a part with a molding material, comprising: - a rigid molding element (100) suitable for shaping one face of the part, - a flexible, airtight, unsupported sheet (200) peripherally connected to the rigid molding element (130) in an airtight manner so that they define between themselves a molding zone whose shape is generally defined by the molding element, - a vacuum source (120) connected to the molding area, so that a vacuum can be exerted in the molding area during or after the introduction of molding material into said area, an installation characterized in that the airtight flexible sheet (200) is pre-constituted of a sheet comprising a dry layer (201) of a paint-type material attached to a backing (202) having anchoring arrangements on the side opposite the layer of paint-type material, the backing being turned towards the molding element and being able to anchor itself in the molding material as the latter spreads into the molding area.

12. Installation according to claim 11, characterized in that it also comprises a reinforcing material (140, 141) placed in the molding area and intended to be embedded in the molding material.

13. Installation according to any one of claims 11 and 12, characterized in that the molding material consists of a resin (R), in particular an impregnable resin.

14. Installation according to claim 13, characterized in that the resin supply is carried out by a process included in the following group: infusion, pre-impregnation, contact molding, resin transfer molding, filament winding.

15. Installation according to any one of claims 11 to 14, characterized in that the backing (202) of the sheet (200) is a fibrous backing, the anchoring arrangements comprising fibers extending beyond the layer of paint-type material.

16. Installation according to any one of claims 11 to 15, characterized in that the molding element (100) and the sealing sheet (200) extend beyond the contours of the part to be produced by marginal areas.

17. Installation according to any one of claims 11 to 16, characterized in that the vacuum source (120) is connected to the molding area by at least one vacuum port (122) passing through said foil.

18. Use of a pre-made sheet (200) of a dry layer of a paint-like material (201) anchored in a folder (202) having anchoring arrangements on the side opposite the layer of paint-like material, for its application against a face of a part opposite a mold element while being unsupported, in order to define between the sheet and the mold element, by themselves, a sealed molding space into which a molding material can be brought and into which a vacuum can be applied.

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