Method for manufacturing a composite product

Abstract

A method for manufacturing a composite product includes folding a first layer of material to create a first folded layer having a first and a second superposed portion extending from a respective first and second free end to a first bend, folding a second layer of material in order to create a second folded layer having a third and a fourth superposed portion extending from a respective third and fourth free end to a second bend, laying the first folded layer over a first element with the first portion in contact with the first element, laying the second folded layer over the first folded layer laying a second element over the second folded layer, compressing the plurality of the fiber layers by either vacuum or gravity, pulling two free ends of the first folded layer and of the second folded layer in order to let them contact each other.

Claims

1. A method for manufacturing a composite product comprising: folding a first layer in order to create a first folded layer comprising a first and a second superposed portion extending from a respective first and second free end to a first bend, folding a second layer in order to create a second folded layer comprising a third and a fourth superposed portion extending from a respective third and fourth free end to a second bend, laying the first folded layer over a support surface with the first superposed portion in contact with the support surface, laying the second folded layer over the first folded layer with the third superposed portion in contact with the second superposed portion of the first folded layer, the first and second folded layers being oriented with respect to each other in order to extend from a first side including the first, second, third and fourth free ends to a second side including the first and second bend, laying a plurality of fiber layers over the second folded layer and laying a cover surface over the plurality of fiber layers, after laying the plurality of fiber layers, applying a vacuum in a volume between the cover surface and the second folded layer, after applying the vacuum, moving an assembly comprising the first and second folded layers, the plurality of fiber layers, and the cover surface over a second support surface with the first superposed portion in contact with the second support surface, and after moving the assembly, pulling the second free end of the first folded layer and the third free end of the second folded layer in order to extract the first and second folded layers from between the plurality of fiber layers and the second support surface in order to let the plurality of fiber layers and the second support surface contact each other.

2. The method according to claim 1, wherein folding the first layer and second layer includes inserting a first plurality of rollers and a second plurality of rollers respectively between the first and the second superposed portions and between the third and the fourth superposed portions, the first plurality of rollers and the second plurality of rollers respectively comprising a first roller at the first bend and a second roller at the second bend.

3. The method according to claim 2, wherein the rollers of the first plurality of rollers and of the second plurality of rollers are uniformly distributed along the first and second folded layers, respectively.

4. The method according to claim 1, wherein folding the first layer and second layer includes inserting a first roller and a second roller respectively between the first and the second superposed portions and between the third and the fourth superposed portions, respectively at the first and second bend.

5. The method according to claim 1, wherein the cover surface is a surface of a gastight membrane.

6. The method according to claim 1, wherein one or the other of the first and second support surface is a surface of a mold.

7. The method according to claim 1, wherein in the assembly comprising the first folded layer and the second folded layer, the second free end and the third free end protrudes with respect to first free end and the fourth free end.

8. The method according to claim 1, further comprising fixing the first free end of the first folded layer and the fourth free end of the second folded layer, before pulling the second free end of the first folded layer and the third free end of the second folded layer.

9. A method for manufacturing a composite product comprising: folding a first layer in order to create a first folded layer comprising a first and a second superposed portion extending from a respective first and second free end to a first bend, folding a second layer in order to create a second folded layer comprising a third and a fourth superposed portion extending from a respective third and fourth free end to a second bend, laying the first folded layer over a support surface with the first superposed portion in contact with the first support surface, laying the second folded layer over the first folded layer with the third superposed portion in contact with the second superposed portion of the first folded layer, the first and second folded layers being oriented with respect to each other in order to extend from a first side including the first, second, third and fourth free ends to a second side including the first and second bend, laying a plurality of fiber layers over the second folded layer and laying a cover surface over the plurality of fiber layers, wherein the cover surface is a rigid surface of a structure or of a mold, after laying the plurality of fiber layers, compressing the plurality of fiber layers via gravity, after compressing, moving an assembly comprising the first and second folded layers, the plurality of fiber layers, and the cover surface over a second support surface with the first superposed portion in contact with the second support surface, and after moving the assembly, pulling the second free end of the first folded layer and the third free end of the second folded layer in order to extract the first and second folded layers from between the plurality of fiber layers and the second support surface in order to let the plurality of fiber layers and the second support surface contact each other.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The aspects defined above and further aspects of the present invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment. The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

(2) FIG. 1 shows a lateral view of an embodiment of a device to be used when manufacturing a composite material according to an aspect of the present invention,

(3) FIG. 2 shows an alternative embodiment of the device of FIG. 1,

(4) FIG. 3A shows a lateral view of a step of a method for manufacturing a composite material according to an embodiment of the present invention,

(5) FIG. 3B shows a step of an embodiment of the method of the present invention to be executed after the step of FIG. 3A,

(6) FIGS. 4 and 5 show two steps, respectively corresponding to the steps shown in FIGS. 3A and 3B, of an alternative embodiment of the method of the present invention,

(7) FIG. 6 shows a step of the method of the present invention to be executed after the step of FIG. 5.

DETAILED DESCRIPTION

(8) FIG. 1 shows a device 100, according to an embodiment of the present invention, to be used as a tool during the manufacturing of a composite product.

(9) The device 100 includes a first folded layer 3 having a first and a second superposed thin portion 30A, 30B. The first superposed thin portion 30A extends from a first free end 3A to a first 180 bend 3C. The second superposed thin portion 30B extends from a second free end 3B to the first 180 bend 3C, which consequently connects the first and the second superposed thin portions 30A, 30B. The first folded layer 3 is folded in order that the second free end 3B protrudes with respect to the first free end 3A, i.e. the second thin portion 30B, in the lateral views of FIGS. 1-6, are longer than the first thin portion 30A.

(10) The device 100 further includes a second folded layer 4 having a third and a fourth superposed thin portions 40A, 40B. The third superposed thin portion 40A extends from a third free end 4A to a second 180 bend 4C. The fourth superposed thin portion 40B extends from a second free end 4B to the first 180 bend 4C, which consequently connects the first and the second superposed thin portions 40A, 40B. The first folded layer 4 is folded in order that the third free end 4A protrudes with respect to the fourth free end 4B, i.e. the third thin portion 40A, in the lateral views of FIGS. 1-6, are longer than the fourth thin portion 40B.

(11) The first and the second folded layer 30, 40 of thin material are made of polypropylene.

(12) According to other embodiments of the present invention, the first and the second folded layer 30, 40 are made of another thin material having low friction properties, and sufficient strength to avoid yielding or breakage.

(13) According to different embodiments of the present invention, the first and second folded layer 3, 4 can be identical or different in dimensions and/or material.

(14) In any case, in the device 100, the first and second folded layer 3, 4 are laid adjacent to each other in order that the second thin portion 30B of the first folded layer 3 is in contact with the third thin portion 40A of the second folded layer 4. The first and second folded layers 3, 4 are oriented with respect to each other in order to extend from a first side including the first, second, third and fourth free ends 3A, 3B, 4A, 4B to a second side including the first and second bend 3C, 4C.

(15) According to possible alternative embodiments of the present invention (FIGS. 3A-3B), the first folded layer 3 and second folded layer 4 include a first roller 5 and a second roller 6 respectively between the first and the second superposed thin portions 30A, 30B and between the third and the fourth superposed thin portions 40A, 40B, respectively at the first and second bend 3C, 4C.

(16) FIG. 2 shows an alternative embodiment of the device 100, where the first folded layer 3 and second folded layer 4 include a first plurality of rollers 5, 5A-K (12 rollers) and a second plurality of rollers 6, 6A-Kb (12 rollers), respectively, between the first and the second superposed thin portions 30A, 30B and between the third and the fourth superposed thin portions 40A, 40B. The first plurality of rollers 5, 5A-K and second plurality of rollers 6, 6A-K respectively includes a first roller 5 at the first bend 3C and a second roller 6 at the second bend 4C, as in the embodiments in FIGS. 3A-3B. The rollers of the two plurality of rollers 5, 5A-K and 6, 6A-K are uniformly distribute along the first and second folded layers 3, 4, respectively, and the device 100 further includes a first plurality of links 7A-K and a second plurality of links 8A-K for respectively linking the rollers in each plurality 5, 5A-K and 6, 6A-K to each other. In each plurality of rollers 5, 5A-K and 6, 6A-K, linking the rollers by means of the links 7A-K and 8A-K keeps them from bundling up on top of each other. The links 7A-K and 8A-K may be rigid or flexible.

(17) According to another possible embodiment (not shown) of the present invention, in each plurality of rollers 5, 5A-K and 6, 6A-K, rollers may be linked by a respective single link.

(18) Embodiments with rollers (FIGS. 2 and 3A-3B) find particular use in applications with high transverse force on the folded layers 3, 4, in order to reduce friction between portions 30A, 30B and 40A, 40B, respectively, during the application of the method according to the present invention.

(19) With reference to FIGS. 3A and 3B, a method for manufacturing a composite product according to an embodiment of the present invention includes: folding a first layer 30 of thin material, for example polypropylene, in order to create the first folded layer 3, folding a second layer 40 of thin material, for example polypropylene, in order to create a second folded layer 4, laying the first folded layer 3 of the device 100 over a first element 1 with the first portion 30A in contact with the first element 1, laying the second folded layer 4 of the device 100 over the first folded layer 3 with the third thin portion 40A in contact with the second thin portion 30B of the first folded layer 3, the first and second folded layers 3, 4 being oriented with respect to each other in order to extend from a first side including the first, second, third and fourth free ends 3A, 3B, 4A, 4B to a second side including the first and second bend 3C, 4C, laying a second element 2 over the second folded layer 4, pulling the second free end 3B of the first folded layer 3 and the third free end 4A of the second folded layer 4 in order to extract the first and second folded layers 3, 4 from between the first and second element 1, 2, in order to let them contact each other smoothly and secondly to go in contact with each other progressively during the extraction step, in order to avoid the wrinkles, bulges or waviness.

(20) According to embodiments of the present invention, before the step of pulling, the method further includes the step of fixing the first free end 3A of the first folded layer 3 and the fourth free end 4B of the second folded layer 4, in order to make more stable and controllable the step of pulling.

(21) In the method embodiment of FIGS. 3A and 3B, a single roller 5, 6 is used at each bend 3C, 4C, respectively.

(22) According to other possible embodiments of the present invention, no rollers inside the folded layers 3, 4 are used (FIG. 1) or a plurality of rollers (FIG. 2) are used.

(23) Rollers are advantageously used in application with high transverse forces acting on the folded layers 3, 4, in particular depending from a high weight of the second element 2.

(24) The radius of rollers 5, 6 or of rollers 5, 5A-K and 6, 6A-K are dependent from the dimensions and mechanical characteristics of the folded layers 3, 4 and of the two elements 1, 2. The choice has to be made chosen in order that the diameters or rollers are: small enough to cause no or minimum disruption in the two elements 1, 2 during extraction, large enough to not cause folds or wrinkles in the folded layers 3, 4.

(25) In the embodiment of FIG. 2 links 7A-K and 8A-K keeps rollers 5, 5A-K and 6, 6A-K from bundling up on top of each other. If the rollers bundle up, then the friction and thus the required pulling force for extracting the folded layers 3, 4 increase, and the risk of disrupting the materials 1, 2 may also increase.

(26) With reference to FIGS. 4 to 6, another embodiment of the method according to the present invention further includes the step of laying the first folded layer 3 over a first support surface 11 of a third element 21 with the first portion 30A in contact with the first support surface 11 (FIG. 4). The second element 2 includes a plurality of fibre layers 9 laid over the second folded layer 4 and a cover surface 10 laid over the plurality of fibre layers 9.

(27) The third element 21 is any element which can provide a first support surface 11 for easily and conveniently performing the following steps of the method, in particular the step of laying the fibre layers 9 over the second folded layer 4. Normally, in known application, fibre layers 9 are laid directly over a mould or over other stacks of fibre layers which are not always easily reachable, thus increasing the risk of bulges or wrinkles formation.

(28) Before pulling (FIG. 5) the second free end 3B of the first folded layer 3 and the third free end 4A of the second folded layer 4 in order to extract the first and second folded layers 3, 4, this embodiment of the method further includes moving the assembly including the first and second folded layers 3, 4, the plurality of fibre layers 9 and the cover surface 10 over a second support surface 12 of the first element 1 with the first portion 30A in contact with the second support surface 12.

(29) The second support surface 12 may be the upper surface of a mould or of another stack of fibre layers.

(30) After extracting the first and second folded layers 3, 4, the method further includes removing the cover surface 10 from over the fibre layers 9 (FIG. 6). After this, the manufacturing of the composite product continues with the repletion of the steps above described in order to place another stack of fibres on top of the stack of fibres 9. Alternatively the manufacturing of the composite product continues with conventional steps, known in the field of the moulding technology.

(31) The cover surface 10 is any surface which makes easy and practical moving the stack of fibre layers 9 from the first support surface 11 to the second support surface 12.

(32) In particular, according to another embodiment of the present invention the cover surface 10 is a gastight membrane and the method includes applying vacuum in the volume between the cover surface 10 and the second folded layer 4 in order to compress the fibres layers 9 and, therefore, make it easier to move the entire stack of fibres from the first support surface to the second support surface.

(33) According to a further embodiment of the present invention (not shown) the cover surface 10 is the rigid surface of a structure or mould. In this case, instead of vacuum, a transverse force to compress the fibres layers 9 may be exerted by means of gravity or hydraulics devices.