Thermocompression method for manufacturing a part made of a composite material having a thermoplastic polymer matrix

Abstract

The invention relates to a thermocompression method for manufacturing a part, made of composite material having a thermoplastic polymer matrix, in a mould (2) having a forming surface (3), the method comprising the following steps: a) providing a deformable punch (7); b) providing at least one thermoplastic polymer material (30) and a fibrous reinforcement material (31); c) positioning the thermoplastic polymer material (30) and the fibrous reinforcement material (31) in the mould (2) between the forming surface (3) and the punch (7); d) positioning a flexible membrane (5) on one side of the punch (7) opposite the forming surface (3); e) heating the mould (2); f) applying a pressure to the membrane (5) using a pressurised fluid, in order to deform the punch (7) and enable it to adapt to a variation in the thickness of the materials present between the punch (7) and the forming surface (3).

Description

[0001] Description

[0002] Title: Thermocompression process for manufacturing a part from thermoplastic polymer matrix composite material

[0003] technical field

[0004] The present invention relates to the field of manufacturing parts from composite materials. In particular, the invention relates to a thermocompression process for manufacturing a part from a thermoplastic polymer matrix composite material and a thermocompression installation for implementing this process.

[0005] Previous technique

[0006] To manufacture parts from thermoplastic polymer matrix composite materials, stamping is a common method. This involves preheating the composite material and then transferring it into a punch / die mold when its temperature is sufficient to withstand the deformations imposed by the stamping action. The raw material used is generally in the form of a consolidated composite sheet. During the preheating stage, the stack of composite plies is, in a sense, deconsolidated since it is heated beyond its transformation temperature, or beyond its melting point in the case of a semi-crystalline matrix.

[0007] When producing deep or hollow parts, stamping, like thermoforming thermoplastic sheets, has limitations because the deformation rates demanded of the molten material can become too high, leading to material failure. Adding movement during preheating (as described, for example, in US patent 8663531) or during shaping in the mold (patent WO2005123369A1) may be necessary to ensure deformation rates compatible with the behavior of the material.

[0008] On the other hand, the consolidation pressure applied along an axis normal to the surfaces may be insufficient on faces with draft angles close to 0°. In this case, flexible punches can be used. When the geometries are more complex or deep, or when the thermoplastic matrix composite structure to be processed is not homogeneous in thickness, the thermocompression process may be much more suitable. Thermocompression includes the preparation of the materials (cutting, stacking), their positioning on a part of the mold (either the punch or the die), closing the mold by bringing the two mold parts together, the thermocompression itself by applying a predetermined pressure and a predetermined thermal field to the stack of materials, cooling the parts by cooling the mold, and demolding at an appropriate temperature.

[0009] In cases where the punch and mold die are rigid and the part geometry is complex (i.e., featuring curves, changes in slope, radii, etc.), it is not possible to achieve homogeneous consolidation pressure at every point in the raw material. This results in differences in material flow or internal stresses due to the process. Local fiber content or the mechanical behavior of the structure may also exhibit heterogeneities depending on the areas studied.

[0010] When the mechanical behavior of the composite structure is to be controlled homogeneously throughout the structure, the use of a sheet or membrane is preferred to act as a counter-mold; depending on the reference surface of the part (concave or convex surface), the membrane or sheet will be positioned on the material on the opposite side: if the reference surface of the part is the concave part, the rigid mold will be a male mold and the membrane will be placed on the convex side of the part, and vice versa.

[0011] Such tarpaulin molding processes are described for example in documents GB 2571088, GB2574108 and FR3105077.

[0012] However, document FR3105077 does not mention the difficulty of installing and maintaining the composite plies in the molding cavity before the membrane is put in place, especially when the composite lamination consists of dry fiber fabric and thermoplastic film, which are slippery.

[0013] In the case of hollow composite parts, a moving core can be used, as stipulated in document FR3018719.

[0014] The process described in document US6290895 can also be cited.

[0015] Description of the invention There is a need to further improve the manufacturing processes for parts made of thermoplastic polymer matrix composite materials.

[0016] Summary of the invention

[0017] The present invention meets this need by means of, according to one of its aspects, a thermocompression process for manufacturing a part in a thermoplastic polymer matrix composite material in a mold having a forming surface, comprising the following steps: a) providing a deformable punch; b) providing at least one thermoplastic polymer material, and a fibrous reinforcing material; c) positioning the thermoplastic polymer material and the fibrous reinforcing material in the mold between the forming surface and the punch; d) positioning a flexible membrane on one side of the punch opposite the forming surface;e) heat the mold so as to melt the thermoplastic polymer material, which is in particular in contact with the forming surface, within the mold; f) apply pressure using a pressurized fluid on the flexible membrane, the pressure being sufficient to deform the punch so as to allow it to adapt to a variation in thickness of the materials present between the punch and the forming surface during the process.

[0018] Thanks to the use of a deformable punch, capable of adapting to variations in material thickness between the punch and the forming surface during the process, the invention makes it possible to produce composite parts with high precision and consistent, repeatable quality, even when they have a significant hollow. Indeed, thanks to this deformation, during manufacturing and consolidation, the punch can apply a substantially isobaric pressure to the materials.

[0019] The term "materials present between the punch and the forming surface" means at least one thermoplastic polymer material and at least one fibrous reinforcing material. In particular, other materials may be present, such as inserts or other technical layers. After step c), at least some of the materials present between the punch and the forming surface may be in contact with the forming surface.

[0020] The punch may include at least one preferential deformation zone during step f). During step f), said at least one preferential deformation zone undergoes, in particular, a deformation visible to the naked eye.

[0021] The punch may include at least one slot facilitating the movement or deformation of at least a part of the punch during step f).

[0022] During step f), the membrane can apply pressure to the materials between the punch and the forming surface through said at least one slot. In this case, during step f), the membrane is preferably in contact with the materials between the punch and the forming surface at said at least one slot.

[0023] The punch may include two slots facilitating the movement or deformation of at least a part of the punch between the two slots during step f).

[0024] The punch can be semi-rigid. The punch can include at least one rigid zone, configured to undergo substantially zero deformation during step f), and one flexible zone configured to undergo deformation during step f).

[0025] By "undergo a deformation", we mean that in this area, during step f), a deformation is visible to the naked eye.

[0026] The deformation of the punch in step f) can be progressive during the process.

[0027] The deformation of the punch in step f) is preferably an elastic deformation. Such an elastic deformation allows the punch to be reused for several cycles without being damaged.

[0028] Steps e) and f) can be simultaneous.

[0029] The process may include, after step f), a cooling step g) in which the punch may remain under pressure and deformed. The cooling step g) is advantageously free of heating of the mold.

[0030] During step f), and possibly during step g) of cooling, the pressure applied to the flexible membrane may be greater than or equal to 10 bar, in particular between 20 bar and 80 bar.

[0031] The punch may include a window; the membrane applies pressure, during step f), to the materials between the punch and the forming surface through the window. The use of such a window can facilitate the local formation of a specific geometry without excessively stiffening the punch.

[0032] During step f), the membrane is preferably pressurized using a pressurized fluid on one side of the membrane opposite the punch.

[0033] After step d) and before step f), the process may include a step of positioning a counter-mold in the membrane on one side of the membrane opposite the punch.

[0034] After the counter-mold positioning step, a closed cavity can be formed between the counter-mold and the membrane. During step f), the pressurized fluid is advantageously injected into said closed cavity.

[0035] The pressurized fluid is advantageously a pressurized gas, in particular pressurized air.

[0036] Materials

[0037] During step e), the heating temperature is advantageously lower than the melting or degradation temperature of at least some of the fibers of the fibrous reinforcing material.

[0038] In step c) of positioning, the thermoplastic polymer material and the fibrous reinforcing material can first be positioned around the punch and then the assembly formed by the thermoplastic polymer material, the fibrous reinforcing material and the punch is positioned in the mold, in particular against the forming surface.

[0039] Pre-positioning the thermoplastic polymer and the fibrous reinforcing material, which in some cases form a loose assembly, on the punch facilitates their positioning in the mold. This can be achieved, in particular, without pre-gluing the materials together, thus limiting unwanted material during the material stacking process.

[0040] The thermoplastic polymer material and the fibrous reinforcing material can be held in position around the punch before positioning in the mold using clamps.

[0041] The clamps may be ejected into the punch during the positioning of the assembly formed by the thermoplastic polymer material, the fibrous reinforcing material and the punch or during step c). After step c), said at least one thermoplastic polymer material and / or said at least one fibrous reinforcing material may have an external shape homothetic to the forming surface of the mold.

[0042] After step b) of material supply, said at least one thermoplastic polymer material and / or said at least one fibrous reinforcing material may have a three-dimensional shape, in particular hollow. According to one embodiment, said at least one thermoplastic polymer material and / or said at least one fibrous reinforcing material may be a three-dimensional knit.

[0043] The fibers forming said at least one fibrous reinforcing material may be mineral fibers, in particular carbon, glass or basalt, vegetable fibers, in particular flax or bald, or polymer material fibers, in particular polymer material whose melting temperature is lower than the melting temperature of said at least one thermoplastic polymer material.

[0044] The fiber density of said at least one fibrous reinforcing material may vary locally.

[0045] The amount of thermoplastic polymer in said at least one thermoplastic polymer material may vary locally.

[0046] After step b) of material supply, said at least one thermoplastic polymer material may be separated from said at least one fibrous reinforcing material, forming in particular two separate elements. The fibrous reinforcing material may be dry. The fibrous reinforcing material may comprise a fiber textile, in particular a fiber knit. In one embodiment, the fibrous reinforcing material is formed from an assembly of fiber textiles, in particular an assembly of fiber knits. The thermoplastic polymer material may be in the form of a film.

[0047] Alternatively, after step b) of supplying the materials, said at least one thermoplastic polymer material may be bonded or mixed with said at least one fibrous reinforcing material, forming in particular a single element.

[0048] In this case, the single element may be formed from a mixture, in particular a textile, preferably a knit, of fibers forming said at least one fibrous reinforcing material and of fibers forming said at least one thermoplastic polymer material.

[0049] In this case, the single element may be formed from a mixture, in particular a textile, preferably a knit, of multi-material fibers made of at least two different materials. The multi-material fibers may include a core intended to form said at least one fibrous reinforcing material and a coating intended to form said at least one thermoplastic polymer material. In one embodiment, the multi-material fibers are made of several polymer materials. The multi-material fibers may be made of self-reinforced polypropylene (SrPP).

[0050] In this case, the single element may be formed by a fiber textile, intended to form said at least one fibrous reinforcing material, powdered or impregnated with a thermoplastic polymer material. The use of powdering allows for local adjustment of the quantity of thermoplastic polymer material.

[0051] Thermocompression installation

[0052] The invention also relates, according to another aspect, in combination with the foregoing, to a thermocompression installation for manufacturing a part made of thermoplastic polymer matrix composite material for implementing the process as defined above, comprising:

[0053] - a heated mold with a forming surface;

[0054] - a deformable punch;

[0055] - a flexible membrane configured to be positioned on the punch;

[0056] - a pressurization means using a fluid configured to apply pressure to the membrane during thermocompression.

[0057] The membrane can be made of an elastomeric material, particularly silicone. The membrane can have a shape similar to the forming surface of the mold.

[0058] The punch can be in the form of a shell.

[0059] By "shell" we mean an object whose wall defines an open cavity, this object having an E / D ratio between the thickness E of the wall and its largest dimension D less than or equal to 1 / 10, in particular less than or equal to 1 / 200.

[0060] The punch may include a surface with a raised feature, such as an engraving, texture, or rib. This raised feature can modify the appearance of the manufactured part, for example, for aesthetic or technical reasons, to enhance the part's functionality, or to reinforce it in certain areas.

[0061] The punch may include a reference element to control its positioning in the mold. The reference element may be a lug or a shoulder.

[0062] The punch can be semi-rigid. The punch can include an opening.

[0063] The punch may include at least one preferential deformation zone.

[0064] The punch may include at least one slot extending from the opening, said at least one slot being configured to facilitate the displacement or deformation of at least a portion of the punch when pressure is applied inside the punch during thermocompression.

[0065] The punch may include a base from which side walls extend, in particular four side walls, said at least one slot extending between two adjacent side walls, in particular over at least 50%, better over at least 80%, of the height of the side wall.

[0066] The punch may include a plurality of slots.

[0067] A slot extends, preferably, between each pair of adjacent side walls.

[0068] The width of said at least one slot can be between 1 mm and 300 mm.

[0069] The width of said at least one slot may be variable or constant.

[0070] The punch can be made of composite material. This can make it lighter and allow for better control of its mechanical properties.

[0071] The punch may comprise a first zone and a second zone, the composition and / or structure of the first zone being different from the composition and / or structure of the second zone.

[0072] The thickness of the punch can vary.

[0073] The punch may include a window configured to allow, during thermocompression, the application of pressure by the membrane on the materials present between the punch and the forming surface through the window.

[0074] The punch may include a housing allowing the positioning of an insert during thermocompression.

[0075] The pressurization means may include a counter-mold configured to be positioned in the membrane on one side of the membrane opposite the punch at least during thermocompression.

[0076] The counter-mold may include one or more injection channels for a pressurized fluid. Brief description of the drawings

[0077] The invention will be better understood by reading the detailed description that follows, by examining the non-limiting examples of its implementation, and by examining the attached drawing, in which

[0078] [Fig 1] illustrates, schematically, in cross-section, an example of a thermocompression installation according to the invention,

[0079] [Fig 2] illustrates, in cross-section and in isolation, the punch of the installation of figure 1,

[0080] [Fig 3] illustrates, in perspective, another example of a punch for an installation according to the invention,

[0081] [Fig 4] illustrates, in top view, the punch of figure 3,

[0082] [Fig 5] illustrates, in perspective, another example of a punch for an installation according to the invention,

[0083] [Fig 6] illustrates, in top view, the punch of figure 5,

[0084] [Fig 7] illustrates, in cross-section, schematically, a step of a process according to the invention for positioning a thermoplastic polymer material and a fibrous reinforcing material on the punch of the installation of figure 1,

[0085] [Fig 8] illustrates, in cross-section, schematically, a step of a process according to the invention for positioning the thermoplastic polymer material, the fibrous reinforcing material and the punch of figure 7 in the mold of the installation of figure 1,

[0086] [Fig 9] illustrates, in cross-section, schematically, a step of a process according to the invention of applying pressure in the punch of figure 8 using the membrane of the installation of figure 1,

[0087] [Fig 10] is a view similar to Figure 3 illustrating the directions of wall displacement during thermocompression according to a process according to the invention, and

[0088] [Fig 11] illustrates, in cross-section, schematically, another example of a punch of an installation according to the invention.

[0089] Detailed Description In the following description, identical elements or elements with identical functions are marked with the same reference numeral. For the sake of brevity, they are not described alongside each figure; only the differences between the embodiments are described.

[0090] In the figures, the actual proportions have not always been respected, for the sake of clarity.

[0091] Figures 1 and 2 illustrate an example of a thermocompression installation 1 according to the invention.

[0092] Installation 1 includes a metallic mold 2, having a hollow forming a forming surface 3.

[0093] Mold 2 is a heated mold.

[0094] Installation 1 also includes a flexible membrane 5, for example made of silicone, whose external shape can conform to the shape of the forming surface 3.

[0095] In this example, membrane 5 has a constant thickness.

[0096] The installation also includes a means of pressurization using a fluid, which in this example comprises a rigid counter-mold 6, specifically metallic. The counter-mold 6 is configured to be positioned over the membrane 5 and allows the injection of a pressurized fluid via channels 61 to apply pressure to the membrane 5 during thermocompression, as will be described later.

[0097] Installation 1 also includes a deformable punch 7 which, during thermocompression, is positioned between the forming surface 3 and the membrane 5.

[0098] Punch 7, for example, is made of a composite material.

[0099] The punch 7 has a general shell shape whose outer surface 8 has a shape similar to the forming surface 3.

[0100] As illustrated in Figure 2, the punch 7 has a base 10 from which lateral walls 11 extend. The punch 7 also has an opening 12.

[0101] The side walls 11 have a thickness el near the opening 12 which is, in this example, substantially identical for each of the side walls 11.

[0102] In this example, at a junction 13 between a side wall 11 and the bottom 10, the thickness e2 of the punch 7 is reduced relative to the thickness e1, for example by at least 50%. The junction 13 is also curved. This reduction in thickness at the junction 13 increases the flexibility of the punch 7 at this point. This allows the punch 7 to deform at the junction 13 during thermocompression, enabling the relevant side wall 11 to move relative to the bottom 10.

[0103] At the periphery of the junction 13, the thickness e3 of the bottom 10 can be substantially identical to the thickness el.

[0104] In this example, the variation in thickness between the side wall 11 and the junction 13 is progressive.

[0105] In this example, the interface between the bottom 10 and the junction 13 forms a shoulder

[0106] The bottom 10 includes, in a zone 14, a reduction in thickness, for example to a thickness e4 less than a quarter of the thickness e3. The variation in thickness at the periphery of the zone 14 is progressive.

[0107] Punch 7 includes a window 15 at the junction between a side wall 11 and the bottom 10.

[0108] The window 15 allows the formation of a local indentation on the part. During thermocompression, the indentation is shaped using a domed part 16 of the forming surface 3 and an indentation 17 in the membrane 5.

[0109] In order for this recess to be produced correctly, particularly in geometric terms, the thickness of the punch 7 at the periphery of the window 15 is increased, so as to reduce the flexibility of the punch 7 at this level.

[0110] For example, at the bottom, the thickness e5 doubles after a shoulder 18 compared to the thickness e3 and then increases progressively as it approaches the window 15. On the side wall 11, the thickness e6 increases progressively as it approaches the window 15 to double compared to the thickness el.

[0111] As illustrated, the different thickness variations occur on the inside of the punch. In other words, the thickness variations are not visible on the outside surface 8.

[0112] Figures 3 and 4 illustrate a variant of punch 7.

[0113] In this variant, the punch 7 includes a base 10, four side walls 11 and two windows 15.

[0114] The punch 7 may have a generally hollow parallelepiped shape. The adjacent lateral walls 11 are separated by slots 20.

[0115] These different slots 20 allow, during thermocompression, the movement of each lateral wall 11 towards the outside of the punch 7, therefore towards the forming surface 3 of the mold 2.

[0116] Two slots 20a extend from the opening 12 to a window 15. The slots 20a have, for example, a width La, measured between the lateral walls 11 bordering the slot 20a, of a constant of approximately 5 mm.

[0117] The slots 20a extend from the opening 12 over a height Ha equal for example to about 30% of the height H of the side walls 11.

[0118] The two other slots 20b extend from the opening 12 and have a width Lb, measured between the side walls bordering slot 20b, substantially constant and about 80 mm.

[0119] The slots 20b extend from the opening 12 over a height Hb equal to the height H of the side walls 11.

[0120] The junction 13 of each side wall 11 with the bottom 10 is, in this example, convex with respect to the outside.

[0121] A variant of punch 7 from figures 3 and 4 is illustrated in figures 5 and 6.

[0122] In this variant, the punch 7 has two additional windows 15 at the slots 20b. The slots 20b extend from the opening 12 to one of the additional windows 15.

[0123] The windows 15 at the level of the slots 20b have a smaller area than the area of ​​the windows 15 at the level of the slots 20a.

[0124] Furthermore, the width of slots 20b is approximately equal to that of slots 20a.

[0125] In this variant, three of the junctions 13 are convex with respect to the outside and one junction 21 is concave with respect to the outside.

[0126] An example of a manufacturing process for a part made of composite material is illustrated in figures 7 to 9.

[0127] For this example, punch 7 described in figures 1 and 2 is used.

[0128] In a first step, a film 30 of thermoplastic polymer material, for example polycarbonate, and a knit 31 of fibers, for example glass or carbon, are provided. The knit 31 has a three-dimensional shape homothetic to the forming surface 3, and more generally similar to the shape of the part to be produced.

[0129] The knit 31 and the film 30 are then positioned around the punch 7 opposite the outer surface 8 of the punch 7.

[0130] This operation is performed outside of mold 2.

[0131] In this example, the film 30 and the knit 31 are held in position on the punch 7 by means of clips 32. The film 30, the knit 31 and the punch 7 are thus joined together, which facilitates the handling of the assembly by an operator or a robot.

[0132] In a second step, illustrated in figure 8, the assembly formed by the film 30, the knit 31 and the punch 7 is positioned in the mold 2.

[0133] This positioning causes the 32 clamps to be ejected into the punch 7. These clamps are then retrieved by an operator.

[0134] The film 30 and the knit 31 are thus positioned between the forming surface 3 and the punch 7.

[0135] As illustrated, a side wall l ia of the punch 7 is, at this stage of the process, not parallel to the forming surface 3 of the mold 2.

[0136] At this stage, the materials present between the punch 7 and the forming surface 3 are in a loose, i.e., uncompacted state, and have a thickness EL

[0137] Next, the membrane 5 is positioned in the punch 7, then put under pressure by the counter-mold 6 using a fluid, in particular a gas, as illustrated in figure 9.

[0138] In particular, the counter-mold 6 is positioned in the membrane 5 on one side of the membrane 5 opposite the punch 7 to form a closed cavity 62 between the counter-mold 6 and the membrane 5. The pressurized fluid is injected into this closed cavity 62 via the channels 61.

[0139] This pressurization of the membrane 5 deforms it elastically to press it against the punch 7 and thus applies a pressure P substantially isobaric on the punch 7, for example a pressure of about 50 bar.

[0140] In addition, the membrane 5 applies direct pressure to the materials between the punch 7 and the forming surface 3 at the window 15.

[0141] The pressurization may be accompanied by air drainage between the membrane 5 and the punch 7 and / or between the punch 7 and the forming surface 3. Simultaneously, the mold 2 is heated to a heating temperature higher than the melting temperature of the polymer material of the film 30, and lower than the degradation temperature of the knit fibers 31. This heating allows the polymer material to melt and penetrate the knit 31.

[0142] This fusion and penetration results in a reduction of the thickness of the materials present between the punch 7 and the forming surface 3 to a thickness E2, for example less than half the initial thickness El.

[0143] The pressure applied to the punch 7 is sufficient to progressively deform the punch 7 so as to allow it to adapt to this variation in thickness of the materials present between the punch 7 and the forming surface 3, as thermocompression occurs.

[0144] In particular, junction 13 is deformed, thanks to the reduction in thickness, allowing the outward movement of wall l ia.

[0145] In this example, only junction 13 is deformed, wall l ia undergoing virtually no deformation.

[0146] Next, the heating of mold 2 is stopped, while maintaining the pressure of membrane 5, so as to cool the materials between punch 7 and forming surface 3.

[0147] A part made of composite material is thus obtained, its fibrous reinforcement being derived from the fibers of the knit 31 and its matrix from the thermoplastic polymer material of the film 30.

[0148] When thermocompression is carried out using the punch described in Figures 3 and 4, each of the side walls 11 will move outwards in a direction De, as illustrated in Figure 10.

[0149] These movements De are made possible by the presence of two slots 20 at the ends of each lateral wall 11. During thermocompression, such a punch 7 will open in the manner of the petals of a flower.

[0150] In addition, the membrane 5 applies pressure to the materials present between the punch 7 and the forming surface 3 through the slots 20.

[0151] The invention is not limited to the examples just described.

[0152] In particular, the shape of punch 7 can vary, for example, parallelepiped, cylindrical, pyramidal, spherical, of revolution, or not, symmetrical, or not. Punch 7 has a shell-like geometry.

[0153] The thickness of the punch 7 can vary, for example, be constant. In this case, the punch 7 may have local variations in material or structure, including a different density and / or fiber orientation when the punch 7 is made of composite material.

[0154] The punch 7 may include a housing 40, as illustrated in Figure 11, allowing the positioning of insert(s) in the mold 2 or to limit the pressure seen by the elements or materials between the punch 7 and the forming surface 3.

Claims

Demands 1. A thermocompression process for manufacturing a part of a thermoplastic polymer matrix composite material in a mold (2) having a forming surface (3), comprising the following steps: a) supplying a deformable punch (7); b) supplying at least one thermoplastic polymer material (30) and one fibrous reinforcing material (31); c) positioning the thermoplastic polymer material (30) and the fibrous reinforcing material (31) in the mold (2) between the forming surface (3) and the punch (7); d) positioning a flexible membrane (5) on one side of the punch (7) opposite the forming surface (3); e) heating the mold (2) so as to melt the thermoplastic polymer material (30) within the mold (2);f) apply pressure using a pressurized fluid on the flexible membrane (5), the pressure being sufficient to deform the punch (7) so as to allow it to adapt to a variation in thickness of the materials present between the punch (7) and the forming surface (3) during the process.; 2. Method according to the preceding claim, the punch (7) comprising at least one preferential deformation zone during step f).

3. Method according to claim 1 or 2, wherein the punch (7) includes at least one slot (20) facilitating the displacement or deformation of at least a part of the punch (7) during step f).

4. Method according to the preceding claim, wherein, during step f), the membrane (5) applies pressure to the materials present between the punch (7) and the forming surface (3) through said at least one slot (20).

5. Method according to claim 3 or 4, wherein the punch (7) comprises two slots (20) facilitating the displacement or deformation of at least a part of the punch (7) between the two slots (20) during step f).

6. A method according to any one of the preceding claims, wherein the deformation of the punch (7) in step f) is progressive during the process.

7. A method according to any one of the preceding claims, wherein steps e) and f) are simultaneous.

8. A method according to any one of the preceding claims, wherein, in the positioning step c), the thermoplastic polymer material (30) and the fibrous reinforcing material (31) are first positioned around the punch (7) and then the assembly formed by the thermoplastic polymer material (30), the fibrous reinforcing material (31) and the punch (7) is positioned in the mold (2).

9. Method according to the preceding claim, wherein the thermoplastic polymer material (30) and the fibrous reinforcing material (31) are held in position around the punch (7) before positioning in the mold (2) using clamps (32), the clamps (32) being ejected into the punch (7) during step c).

10. A method according to any one of the preceding claims, wherein, during step f), the pressure applied to the flexible membrane (5) is greater than or equal to 10 bar, in particular between 20 bar and 80 bar.

11. A method according to any one of the preceding claims, wherein after step b) of supply, said at least one thermoplastic polymer material (30) is separated from said at least one fibrous reinforcing material (31), the fibrous reinforcing material (31) comprising a fiber textile, in particular a fiber knit.

12. A method according to the preceding claim, wherein the thermoplastic polymer material (30) is in the form of a film.

13. A method according to any one of claims 1 to 10, wherein, after step b) of supply, said at least one thermoplastic polymer material (30) is bonded or mixed with said at least one fibrous reinforcing material (31).

14. A method according to any one of the preceding claims, wherein the punch (7) comprises a window (15), the membrane (5) applying, during step f), pressure on the materials present between the punch (7) and the forming surface (3) through the window (15).

15. Installation (1) for thermocompression manufacturing of a part made of thermoplastic polymer matrix composite material for implementing the process according to any one of the preceding claims comprising: - a heated mold (2) having a forming surface (3); - a deformable punch (7); - a flexible membrane (5) configured to be positioned on the punch (7); - a pressurization means (6) using a fluid configured to apply pressure to the membrane (5) during thermocompression.

16. Installation according to the preceding claim, wherein the punch (7) is in the form of a shell.

17. Installation according to any one of claims 15 and 16, wherein the punch (7) comprises an opening (12) and at least one slot (20) extending from the opening (12), said at least one slot (20) being configured to facilitate the displacement or deformation of at least a portion of the punch (7) when pressure is applied inside the punch (7) during thermocompression.

18. Installation according to the preceding claim, wherein the punch (7) comprises a base (10) from which extend side walls (11), in particular four side walls (11), said at least one slot (20) extending between two adjacent side walls (11), in particular over at least 50%, better over at least 80%, of the height (H) of the side wall (11).

19. Installation according to the preceding claim, wherein the punch (7) comprises a plurality of slots (20), one slot (20) extending between each pair of adjacent side walls (11).

20. Installation according to any one of claims 17 to 19, wherein the width (La; Lb) of said at least one slot (20) is between 1 mm and 300 mm.

21. Installation according to any one of claims 15 to 20, wherein the punch (7) is made of composite material.

22. Installation according to any one of claims 15 to 21, wherein the punch (7) comprises a first zone and a second zone, the composition and / or structure of the first zone being different from the composition and / or structure of the second zone.

23. Installation according to the preceding claim, wherein the thickness of the punch (7) is variable.

24. Installation according to any one of claims 15 to 23, wherein the punch (7) includes a window (15) configured to permit, during thermocompression, the application of pressure by the membrane (5) on the materials present between the punch (7) and the forming surface (3) through the window (15).

25. Installation according to any one of claims 15 to 24, wherein the punch (7) includes a housing (40) allowing the positioning of an insert during thermocompression.

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