Method for producing a complex composite part, in particular having a thermoplastic matrix

Abstract

A method for manufacturing a composite part with continuous fiber reinforcement and a polymer matrix from a composite preform. On one of the faces of the composite preform, a demarcated layer of thermoplastic polymer is deposited using an additive manufacturing method.

Claims

1. A method for manufacturing a composite part with continuous fiber reinforcement and a polymer matrix from a first composite consolidated preform comprising a thermosetting polymer, comprising: making an assembly zone by depositing a demarcated layer of thermoplastic polymer comprising dispersed metal particles, adapted to act as a susceptor when subjected to induction or microwaves, on one of faces of the first composite consolidated preform, in a form of lines according to a repeated pattern using an additive manufacturing method, a thickness of the lines ranging from 0.05 to 0.1 mm; and assembling on said one of the faces of the first composite consolidated preform a second preform made of stratified composite material by producing a welded assembly by melting the deposited demarcated layer of the thermoplastic polymer using a dynamic process among one of induction or microwaves.

2. The method according to claim 1, wherein the polymer matrix of one or both of the composite preforms comprises a thermosetting polymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below in its preferred embodiments, which are not limitative in any way, and by reference to FIGS. 1 to 4, wherein:

(2) FIG. 1 is a schematic perspective view of two exemplary embodiments of the use of the process according to the invention;

(3) FIG. 2 is an exploded view from the left of the exemplary assembly of the preforms using additive manufacturing depositions of FIG. 1;

(4) FIG. 3 is a schematic perspective view of an exemplary implementation of the method according to the invention on a dihedral preform; and

(5) FIG. 4 is a schematic perspective exploded view of an exemplary implementation of the method according to the invention on a trihedral preform.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) In FIG. 1 of a schematic exemplary embodiment, the method according to the invention comprises the making of an assembly zone (110) on a consolidated preform (100). Said zone (110) comprises a layer made of thermoplastic polymer. In this exemplary embodiment, the polymer is deposited on the preform (100) in the form of lines (111, 112) that thus form a repetitive pattern. Said lines (111, 112) are deposited on the preform (100) by an additive manufacturing process, for example a process for projecting and melting thermoplastic powder through a nozzle, the movements of which are controlled by a numerical control. Such a method makes it possible to deposit fine lines (111, 112), as the minimum thickness allowed by current technology ranges from 0.05 mm to 0.1 mm. In an exemplary embodiment, the preform (100) is made of a layered structure of fibrous plies with continuous fibers in a thermosetting polymer matrix, for example carbon fibers in epoxy resin. The depositing of thermoplastic lines (111, 112) makes it possible, for example, to create a welding zone.

(7) In FIG. 2, the depositing of thermoplastic film in an assembly zone (110) thus makes it possible to assemble on the face of the preform (100) a second preform (201) made of stratified composite material. In an exemplary embodiment, said second preform also comprises a zone (210) on which a thermoplastic film is deposited by additive manufacturing. Thus, it is possible to weld two preforms (100, 201), wherein the polymer making up the matrix is a thermosetting resin. The deposited thermoplastic polymer is selected for its melting temperature, which is such that the temperature reached during welding does not affect the properties of the thermosetting matrix. Alternatively, the polymer making up the matrix of one of the two preforms, or both of them, is a thermoplastic polymer. In that case, the deposited polymer is for example of the same nature as the polymer making up the to matrix, or is selected deliberately for its melting temperature below the polymer making up the matrix, or for its properties of miscibility with said polymer making up the matrix, depending on the result to be achieved.

(8) In one embodiment, the weld is made statically by pressing the second preform (201) on the first one (100) and raising the temperature of the whole to the is melting temperature of the polymer at the interface of the two parts, for instance in a stove.

(9) In another embodiment, the weld is made dynamically, for example using ultrasound. In other examples of dynamic welding, this is done using induction or microwaves. In that case, the deposited polymer is advantageously charged with particles that can focus the electric field and act as a susceptor. For example, said particles are metal or ceramic particles, such as ferrites.

(10) Returning to FIG. 1, in another implementation of the method according to the invention, a raised form (120) is deposited on the surface of the part.

(11) In FIG. 2, for example, the relief (120) is used as a means to position on the preform (100) a part (202) assembled with it. The part (202) thus added is assembled by welding, gluing or using fasteners. It is made of plastic, composite or metal. Thus, the preform (100) comprises several raised pre-positioning features. For example, the preform is the frame of an aircraft fuselage and the raised feature (120) makes it possible to position a support for a system. Thus, the added part (202) is perfectly positioned on the preform.

(12) Returning to FIG. 1, the use of additive manufacturing for making the raised feature (120) for positioning makes it possible to combine, in the same operation, that is without removing the preform (100) from the machine, the making of the raised feature and the hole (121) that is positioned perfectly in relation to said raised feature, and thus allow the added part to be assembled mechanically, positioned on the raised feature.

(13) In FIG. 3 of another implementation of the method according to the invention, the composite preform (300) comprises two faces, and the additive manufacturing method makes it possible to deposit a raised feature (320), such as a rib extending between the two faces of the preform. Said rib (320) has a structural or functional purpose.

(14) In FIG. 4 of another embodiment of the method according to the invention, the preform (400) is a composite trihedral part obtained by bending along two secant folding lines. Using the additive manufacturing method makes it possible to add a part (420) extending on the three faces of the preform, to close said trihedral preform

(15) The description above and the exemplary embodiments show that the invention achieves the objectives sought, in particular it makes it possible to precisely position an addition of material on a composite preform, and in the same operation, carry out complementary machining, thus perfectly positioned in relation to the preform and said additions of material.