METHOD FOR MANUFACTURING A PART MADE FROM COMPOSITE MATERIAL

Abstract

A method for manufacturing a part made from composite material of a thermoplastic or thermosetting matrix reinforced with fibers includes producing a structure of fibers, that is optionally pre-impregnated. The method further includes aligning and juxtaposing fibers, while stretching them between return elements, and keeping them separated from each other, so as to obtain a first layer. The method includes superimposing, on said first layer, a second layer obtained in an identical manner to the first, in which the fibers are parallel to those of the first layer and kept apart from it. The method includes repeating the superimposing operation until the desired thickness is obtained and stiffening the material making up the matrix (M) by a method that suits its nature.

Claims

1. A method for manufacturing a part made of composite material, comprising the steps of: aligning and juxtaposing fibers, while stretching them between return elements, and keeping them spaced apart from each other, so as to obtain a first layer, superimposing on said first layer, a second layer obtained in a manner identical to the first one, where the fibers are parallel to those of the first layer, and kept apart from the latter, repeating the superposition operation until the desired thickness is obtained, stiffening the material constituting the matrix, by a method specific to its nature.

2. The manufacturing method according to claim 1, wherein a dead spacer turn around the return elements is performed, in order to re-parallelize the fibers (F).

3. The manufacturing method according to claim 1, wherein the distance between the different layers is created by interposing elements therein.

4. The manufacturing method according to claim 3, wherein the interposed elements are comprised of spacers deposited in a robotic manner.

5. The manufacturing method according to claim 3, wherein the interposed elements comprised of spacers deposited by means of an additive manufacturing method.

6. The manufacturing method according to claim 1, wherein the layers are superimposed by maintaining a distance between them with respect to the neighboring one by means of spacers obtained through an additive manufacturing method.

7. The manufacturing method according to claim 1, wherein the layers are superimposed by keeping between them a distance with respect to the neighboring one, by interposing a layer of aligned and juxtaposed fibers, extending in a direction different from that of the layer or layers, which it is into contact with.

8. The manufacturing method according to claim 7, wherein the welding of the intersecting fibers is carried out by a second resin.

9. The manufacturing method according to claim 1, wherein the fibers are previously covered individually with a thermoplastic or thermosetting material so as to form a sheath the thickness creating the distance between the juxtaposed and/or superimposed fibers.

10. The manufacturing method according to claim 1, wherein the fibers are arranged several together, kept parallel and spaced apart two by two and covered with a thermoplastic or thermosetting material so as to form a sheath the thickness creating the distance between the juxtaposed and/or superimposed fibers.

11. A part, comprising: a composite material according to claim 1.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0035] The advantages and features of the method for manufacturing a part made of composite material according to the invention will become more evident from the following description, which relates to the attached drawing, which represents a non-restrictive embodiment of same.

[0036] FIG. 1 shows a schematic view of a filament winding illustrating the prior art.

[0037] FIG. 2 shows a schematic view of a cross-section of a portion of a part made of composite material produced by means of the manufacturing method according to the invention.

[0038] FIG. 3 shows a schematic view of a variant of the same manufacturing method.

[0039] FIG. 4 shows a schematic view of another variant of the same manufacturing method.

[0040] FIG. 5 shows the same schematic view of a part made of composite material produced according to a variant of the same method.

[0041] FIG. 6 shows a perspective view of a step of the same method during the manufacture of a part made of composite material.

DETAILED DESCRIPTION OF THE INVENTION

[0042] FIG. 1 shows a step of a usual method for manufacturing a part made of composite material. Thus, the method consists in making a skein E by winding pre-impregnated fibers F on two axes A and B. Though theoretically the fibers are stretched between the two axes, in reality we observe an increase in thickness at the level of the axes A and B, and especially a transverse swelling in the median portion C and a filling of the space D between the axes A and B, associated with a folding of the fibers F in this area. Therefore, such a method does not permit to achieve the desired goal, namely that the fibers F are rectilinear, in order to be capable of being stressed not only in traction, but also in compression.

[0043] As already mentioned, the term “fibers” is understood to mean all the forms in which the reinforcing fibers can be present, and namely, but non-restrictively, strands or cords of reinforcing fibers.

[0044] When referring now to FIG. 2, we can see a cross-section of a portion of a part P made by means of the method according to the invention.

[0045] This part P includes a matrix M into which reinforcing fibers F are embedded. The method according to the invention consists in arranging the fibers F so that they are kept aligned, parallel to each other and especially perfectly rectilinear.

[0046] To achieve this goal, the fibers are aligned and juxtaposed to form a layer, which is in turn covered with another layer.

[0047] It should be noted that the terms “layer” and “superposition” are not restrictive, they do not involve a mandatory orientation, they are used for ease of understanding.

[0048] In FIG. 1, the portion of the composite part being shown includes three superimposed layers, C1, C2 and C3 of four fibers F each.

[0049] The layer C1 is obtained by stretching four fibers F between return means, not shown, while keeping them spaced apart from each other.

[0050] The layer C2 is made on top of the layer C1, at a distance from the latter, and in the same way, namely by tensioning the fibers F between return means, and the same applies for layer C3.

[0051] According to this embodiment, the distance between two successive layers is obtained by means of return means specific to each layer.

[0052] After the construction of such a structure of fibers F, it is embedded into the matrix M, through various known means, such as, non-restrictively, dipping, molding, casting, infusion, spraying.

[0053] When referring now to FIG. 3, it can be seen that according to a variant of the method according to the invention, maintaining the distance between two successive layers can be achieved not through return means specific to each layer, but through depositing spacer elements E between each of them.

[0054] The spacer means E can be of different types, they can consist, non-restrictively, of fibers arranged in a direction different from those of the layers C1, C2 and C3, or of the resin, identical to the one the matrix M is comprised of.

[0055] It should be noted that, for the purpose of automating the manufacturing method according to the invention, the spacer elements E can advantageously be deposited between each layer by means of an additive manufacturing method.

[0056] When referring to FIG. 4, we can see another variant of implementation of the method according to the invention, in which the particular positioning of the spacer elements E supporting the same layer C1, C2 or C3 of fibers F permits a shaping of each of these layers C1, C2 or C3, so as to provide them for example with a curved shape.

[0057] In the embodiment being shown, it should be noted that the spacer elements E can consist of fibers, while other spacer elements E′ are arranged both between the layers C1, C2 or C3, and between the spacers E.

[0058] FIG. 5 shows another variant of implementation of the method according to the invention. In this variant, F fibers, or more particularly strands, coated with a thermoplastic or thermosetting material are used so as to form around each of them a sheath G with a chosen thickness.

[0059] When making the layers C1, C2 and C3, the sheaths G permit to maintain the distance between the fibers F of the same layer, but also between the fibers of two successive layers.

[0060] According to this variant, since maintaining the distance between the fibers is obtained by means of the sheaths G, then only remains to ensure the tension of the fibers.

[0061] It is also possible to provide several fibers arranged in parallel and regularly spaced from each other two by two, the whole being surrounded by a single sheath forming spacer means.

[0062] FIG. 6 shows the fiber structure F of a part V made of composite material, before the operation of associating the matrix M.

[0063] The manufacture of this part V is similar to the method shown in FIG. 4.

[0064] Part V is made of the intersection of parallel walls L and N, where the walls L are flat, while the walls N are curved around a longitudinal axis perpendicular to the walls L.

[0065] The walls L consist of the superposition of layers C1, C2 . . . Cn, each formed of juxtaposed fibers F, kept apart from each other through their tension on return means R, in this case pins, while between each layer C1, C2 . . . Cn is interposed a layer C′1, C′2 . . . C′n of fibers F, spaced apart from each other, stretched over return means, not shown, permitting to perform, through a progressive offset, the curved shaping of the walls N.

[0066] Irrespective of the mode of implementation of the method according to the invention, the desired goal is achieved, namely the straightness of the fibers, which allows optimum tensile as well as compressive strength.

[0067] On the other hand, the method according to the invention is perfectly automatable, which constitutes another aim of the invention.