Needling system for manufacturing a textile preform

Abstract

Needle-punching system (100) for producing a textile preform comprising: - a needle-punching head (110); - a robotic arm (120) mobile with several degrees of freedom, carrying the needle-punching head and configured to move the needle-punching head along predetermined trajectories and orientations; - a textile strip feeding device (130) mounted on the needle-punching head and configured to deposit the textile strip onto a support and cut it, and - a control unit (140) configured to control the robotic arm, the actuation of the needle-punching head and the depositing of the textile strip according to a predefined program for producing the textile preform.

Description

Technical Field

[0001] The present invention relates to the manufacture of textile preforms by needling, and more particularly to a needling system for the manufacture of a textile preform. Prior art

[0002] Textile preforms form the reinforcement of organic or ceramic matrix composite materials. They form a frame for the material, absorbing most of the mechanical stress, which is reinforced and protected by the organic or ceramic matrix of the composite material.

[0003] The production of textile preforms by needling consists of superimposing textile plies and binding these plies together by needling. In particular, needling consists of binding the plies together by transferring fibers from one ply to another in the Z direction, i.e. along the thickness of the preform, thus creating mechanical connections between the plies in this direction. Current needling systems thus make it possible to produce axisymmetric preforms or preforms with an open geometry.

[0004] Current needling methods are programmed to follow a certain trajectory in order to needle the preform according to certain criteria, such as the Z-shaped fiber density. Current programs are specific to the machine used and cannot be used on another. In addition, they can follow an axisymmetric profile based on an adaptive mode, which allows the position of the machine to be corrected according to the excess thicknesses encountered during needling.

[0005] However, some preforms, such as atmospheric re-entry thermal protection preforms, may have a spherical cap shape (non-opening geometry) or a non-axisymmetric geometry and current needling methods are not suitable for this type of geometry.

[0006] It is therefore desirable to have a new, more versatile needling system that can needle preforms whose geometry is non-axisymmetric and / or non-opening, or whose geometry is axisymmetric or not, open-ended or not, and capable of needle-punching textile strips whose trajectories are fully configurable, without trajectory limitation.

[0007] It is also desirable to have a new needling means programming solution that can be used on several needling machines and adapt to any type of preform geometry, including non-axisymmetric and non-through geometries. Statement of the invention

[0008] The present invention relates to a needling system for producing a textile preform comprising: a needling head; a robotic arm movable according to several degrees of freedom, carrying the needling head and configured so as to move the needling head along predetermined trajectories and orientations; a device for feeding a textile strip mounted on the needling head and configured to deposit the textile strip on a support and cut it, and a control unit configured to control the robotic arm, the actuation of the needling head and the deposit of the textile strip according to a predefined program for producing the textile preform.

[0009] The invention thus proposes a modular needling head because, thanks to the robotic arm, it can adapt to complex preform geometries. The needling system of the invention therefore makes it possible to manufacture preforms with non-opening geometry, such as a spherical cap, or non-axisymmetric geometries. The needling system of the invention also makes it possible to parameterize trajectories of custom textile strips, without trajectory limitation.

[0010] In addition, the presence of the device for feeding a textile strip on the needling head makes it possible to envisage depositing a strip and needling it onto the previously deposited strips simultaneously with a single system. This makes it possible to deposit the textile strips in various directions in low or high thickness, and also to automate the placement of the strips thanks to the robotic arm and the control unit. This also makes it possible to do without a fixing additive between the strips or other elements that could pollute the strips forming the preform and that could disrupt the fiber / matrix bonds during the densification of the needled preform, because the strips are held together during needling by the partial transfer in the transverse direction of the fibers coming from the deposited strips.In other words, in the case of the invention, it is a mechanical bonding of the textile strips and not a chemical bonding unlike the methods of the prior art allowing the textile strips and / or the threads to be laid and held (such as automatic tape laying, ATL, and automatic fiber placement, AFP).

[0011] According to a particular characteristic of the invention, the device for feeding a textile strip comprises a regulation system, for example a braking system, configured to adjust the tension of the textile strip when it is placed on the support according to a given instruction, or according to a particular point of the trajectory.

[0012] According to another particular characteristic of the invention, the device for feeding a textile strip comprises a system for guiding the textile strip.

[0013] According to another particular characteristic of the invention, the textile strip guidance system comprises adjustable detour rollers according to at least one spherical three-dimensional reference point.

[0014] According to another particular characteristic of the invention, the device for feeding a textile strip comprises a lateral position regulation system.

[0015] This allows for more precise guidance of the strip and its placement on the support. This can be particularly useful in the case where a slicing operation is carried out, as illustrated in figure 3 , allowing a slight translation of the strip to correct any possible positioning error during removal.

[0016] Another subject of the invention relates to a method for manufacturing a textile preform by needling implemented by the needling system of the invention on a support tool whose shape corresponds to that of the textile preform to be produced, the method comprising the deposition and needling of a textile strip on the support tool.

[0017] This process allows the textile strip to be needled directly to the shape of the final preform.

[0018] According to a particular characteristic of the invention, the support tool has a non-axisymmetric and / or non-opening shape.

[0019] This allows the production of preforms with complex geometry.

[0020] According to another particular characteristic of the invention, the textile strip is deposited and needled onto the support tool without limitation of trajectory.

[0021] According to another particular characteristic of the invention, the needling head forms an angle of between -85° and 85° relative to the direction perpendicular to the tangent plane of the support tool during all or part of the deposition and needling of the textile strip.

[0022] This allows the fibers to be transferred, during needling, in a direction perpendicular or non-perpendicular to the tangent of the preform, i.e. the tangent of the support tool. Not being limited to a perpendicular direction allows the fibers to be transferred in many directions to optimize the thermomechanical properties and the abrasion resistance of the final textile preform according to the applications targeted for the part comprising this preform.

[0023] The present invention also relates to a method for determining a program for moving and orienting a needling head for producing a textile preform by needling a textile strip onto a support tool, comprising at least: determining a set of triplets of coordinates (x, y, z) of the passage points of the needling head as a function of the positions of the fibers in the textile preform to be produced, its local geometry and a predetermined minimum distance to be respected between the needling head and the support tool or the preform making it possible to avoid a collision with the latter, and determining the angular orientation of the needling head (α, β, γ) for each passage point as a function of the angular orientation of the textile strip and the fibers in the textile preform to be produced.

[0024] By means of the method of the invention, the passage points and the orientation of the needling head are determined before starting the needling, taking into account the complexity of the geometry of the preform to be produced, the density and the orientation of the Z fibers while ensuring that the support tooling and the preform do not collide with the needling head. This program is therefore not tied to a particular machine and can be adapted to all machines and desired preform shapes. It thus allows for the versatile production of textile preforms by needling according to the requirements and the desired thermostructural properties, such as for example the Z fiber density and the Z fiber orientation.

[0025] Furthermore, as the complexity of the geometry of the preform to be produced is taken into account, the number of crossing points is adapted to reduce calculation times and the program itself. For example, if an area has a small local radius of curvature, the number of crossing points will be greater in this area than in another area with a larger radius of curvature.

[0026] The determination of the coordinate triplets of the passage points of the needling head and the angular orientation of the head can result from one or more calculations, or certain parameters (coordinate or angle) can be predefined in advance.

[0027] The determination of the triplets of coordinates of the passage points of the needling head can also be carried out according to the width of the textile strip and its possible overlap.

[0028] The determination of the angular orientation of the needling head can be carried out with respect to the normal to the local geometry.

[0029] According to a particular characteristic of the invention, the support tool is rotating around an axis of rotation and the method comprises a mathematical projection of the determined passage points onto a reference plane fixed or mobile relative to the support tool and comprising the axis of rotation of the support tool.

[0030] This allows the coordinate triplets (x, y, z) to be converted into polar coordinates (r, θ, z) and thus makes it easier to implement the coordinates of the needling head passage points in the needling machine.

[0031] According to another particular characteristic of the invention, the method further comprises determining a local movement speed of the needling head as a function of the fiber rate in Z in the associated zone of the preform to be produced and a rotation of the support tool.

[0032] This makes it possible to adapt the needling density according to the geometry of the preform, and thus increase, decrease or keep this density constant according to the local geometric characteristics of the preform.

[0033] According to another particular characteristic of the invention, the method further comprises the production of a mesh of the geometry of the textile preform to be produced, the determination of all the coordinate triplets (x, y, z) being carried out on this mesh.

[0034] The mesh allows a more precise mathematical use of the geometry of the preform to then be able to apply all the operations of determining the passage points and the angular orientation of the head, but also to discretize the number of passage points according to the geometric complexity of the preform to be produced.

[0035] According to another particular characteristic of the invention, the support tool has a non-axisymmetric and / or non-opening shape.

[0036] This makes it possible to produce a textile preform with complex geometry.

[0037] Another subject of the invention is a method for manufacturing a textile preform by needling comprising the determination of a program for moving and orienting a needling head according to the invention and the manufacturing by needling of the textile preform on a support tool, the shape of which corresponds to that of the textile preform to be produced, using a needling head programmed according to the determined program. Brief description of the drawings

[0038] Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate exemplary embodiments thereof which are not limiting in nature. [ Fig. 1 ] There figure 1 represents, schematically and partially, a needling system according to one embodiment of the invention. Fig. 2 ] There figure 2 represents, in part, a needling head during deposition and needling according to an embodiment of the invention. Fig. 3 ] There figure 3 represents, schematically and partially, the needling head of the figure 2 , in particular the orientation of the needles relative to the deposited strip. Fig. 4 ] There figure 4 represents a flowchart of the method for determining a program for moving and orienting a needling head according to one embodiment of the invention. Fig. 5A ] There figure 5A represents, schematically and partially, step 409 of the method described in figure 4 . [ Fig. 5B ] There figure 5B represents, schematically and partially, step 410 of the method described in figure 4 . [ Fig. 5C ] There figure 5C represents, schematically and partially, step 420 of the method described in figure 4 . [ Fig. 5D ] There figure 5D represents, schematically and partially, step 421 of the method described in figure 4 . [ Fig. 6 ] There figure 6 represents a flowchart of the process for manufacturing a textile preform by needling according to one embodiment of the invention. Description of the embodiments

[0039] There figure 1 represents, schematically and partially, a needling system 100 according to an embodiment of the invention making it possible to produce a textile preform.

[0040] The system 100 comprises a needling head 110 on which is mounted a device 130 for feeding a textile strip, a robotic arm 120 movable according to several degrees of freedom and carrying the needling head 110 and a control unit 140.

[0041] The robotic arm 120 is configured to move the needling head 110 along predetermined trajectories and orientations.

[0042] The feeder 130 is configured to deposit the textile strip on a support and cut the deposited strip.

[0043] The control unit 140 is configured to control the robotic arm 120, the actuation of the needling head 110 and the deposition of the textile strip according to a predefined program for the production of the textile preform.

[0044] There figure 2 represents, in part, a needling head 210 carrying a feed device 230 for a textile strip 233 according to an embodiment of the invention during the manufacture of a textile preform, in particular during the deposition and needling of a textile strip 234 on a support tool 250. The figure 3 represents a schematic view of the figure 2 , in particular the orientation of the needles of the needling head relative to the deposited strip, the references used for these two figures representing the same objects.

[0045] The feed device 230 for a textile strip 233 comprises a cassette holder 232 and a cassette 231 containing the textile strip 233 and placed on the cassette holder 232. The cassette 231 has a width corresponding substantially to the width of the textile strip 233 wound on the cassette 231.

[0046] The textile strip 233 is, for example, a strip or a sheet of threads whose properties are useful as fibrous reinforcement in the preform making up a composite material, for example a thread or a set of threads, a fabric, a multidirectional non-woven textile (or “Non Crimp Fabric, NCF”), a braid, or even a non-woven veil.

[0047] The needling head 210 comprises a plurality of needles 211 mounted on a needle board which make it possible to needle the textile strip 234 which has just been deposited on the support tool 250. This textile strip 234 is thus needled with the strips 235 previously deposited in order to produce the textile preform. In order to obtain the desired geometry, the deposition and needling take place on the support tool 250 which has a shape corresponding to that of the preform to be produced. Thus to produce a non-axisymmetric preform, the support tool 250 has a non-axisymmetric shape. The support tool 250 can also be mobile, for example in rotation around an axis, in order to facilitate the movements of the robotic arm and the needling head 210.

[0048] The needling head 210 also includes a stripper 212 comprising a plate having a plurality of perforations. The plate has an internal face and an external face, the external face being present on the side of the support tool 250. The needle board is opposite the internal face of the stripper and the needles 211 are aligned with the perforations present on the stripper plate 212. During the needling of the strip 234, the needles 211 pass alternately from a retracted position in which they do not protrude from the external surface of the stripper plate 212 to a deployed position in which they protrude from the external face of the plate in order to penetrate the textile strip 234. The device 230 for feeding a textile strip 233 is fixed to the needling head 210 transversely to the perforated plate of the stripper 212 intended to be traversed by the needles 211.

[0049] The feed device 230 for a textile strip 233 may comprise a guiding system 270 for the textile strip and / or a braking system which makes it possible to adjust the tension of the strip 234 during its deposition. The guiding system 270 may be fixed on the surface of the stripper 212 or on the needling head 210, ideally as close as possible to the surface of the stripper 210, carrying the feed device 230.

[0050] In addition, the textile web guiding system may be provided with detour rollers 271 adjustable according to a three-dimensional reference frame, in particular in a spherical reference frame. These rollers 271 are for example adjustable in translation according to the direction of the width of the web 234 and adjustable in rotation according to two axes making it possible to adjust the angle of the web 234 relative to the support tool 250. These detour rollers 271 make it possible to guide the web 234 from the cassette 231 to the deposition surface of the support tool 250. The width of these rollers 271 may be adapted to the width of the web 234.

[0051] Whatever the embodiment, the device for feeding a textile strip can be configured to store a textile strip with a width of between 5 mm and 500 mm, preferably between 5 mm and 200 mm.

[0052] Regardless of the embodiment, the needling head can be configured for different widths of needle board (support carrying the plurality of needles) and / or for different stripper widths, for example so as to be able to needle textile strips with a width of between 5 mm and 500 mm, preferably textile strips with a width of between 5 mm and 200 mm. The needle board and the stripper can also be removable from the needling head in order to adapt them to the geometry of the preform to be produced and / or to the widths of the needled textile strips.

[0053] Whatever the embodiment, the needling head, in particular the needles, forms an angle α (represented on the figure 3 ) variable relative to an axis perpendicular 270 to the tangent plane 260 of the support tool 250 during all or part of the deposition and needling of the textile strip, for example this angle is between -85° and 85°, preferably between -30° and 30°. More generally, the needling head is adjustable in all directions around this perpendicular axis 270. This makes it possible to needl the textile strips in different orientations, for example at an angle or at an angle to transfer fibers in a certain orientation to confer certain thermomechanical and / or abrasion resistance properties to the final part.

[0054] Regardless of the embodiment, the needling head can be programmed to move and orient itself, using the robotic arm, around the support tooling to deposit and needle the textile strip. The program for moving and orienting the needling head thus includes the passage points and the angular orientation of the needling head around the support tooling.

[0055] The crossing points can be determined based on the Z-shaped positions of the fibers in the textile preform to be produced, its local radius of curvature and a minimum distance to be respected between the needling head and the support tool or the preform to avoid damaging the preform. The angular orientation of the needling head can be determined for each crossing point based on the angular orientation of the Z-shaped fibers in the preform to be produced.

[0056] Furthermore, in order to facilitate the programming of the needling head, and in the case of a support tool rotating on itself, the waypoints can be expressed in terms of the distance between the needling head and the support tool. For this, the waypoints can be projected into a reference plane fixed relative to the support tool, and thus the head can be programmed according to the distance between the needling head and the support tool.

[0057] Regardless of the implementation method, it is also possible to control the stripper pressure by servo-control. In particular, the stripper can apply pressure to the strip so as to hold it in place when the needles come out.

[0058] Whatever the embodiment, it is also possible to control the needling head by a servo according to the pressure of the stripper and / or according to the position of the stripper if it is floating and / or according to the position of the needles

[0059] It is also possible to control the position of the robot by a servo according to the pressure of the stripper and / or according to the position of the stripper if it is floating and / or according to the position of the needles.

[0060] It is also possible to control the position of the support by a servo according to the pressure of the stripper and / or according to the position of the stripper if it is floating and / or according to the position of the needles.

[0061] There figure 4 represents a flowchart of the method 400 for determining a program for moving and orienting a needling head according to an embodiment of the invention, and the figures 5A , 5B , 5C And 5D represent the different stages of this same process. The process is thus described with reference to the figures 4, 5A , 5B , 5C And 5D .

[0062] The method 400 is a method for determining a program for moving and orienting a needling head 530 for producing a textile preform 500 by needling a textile strip onto a support tool 505. This method 400 comprises the determination 410 of a set of triplets of coordinates (x, y, z), (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) of the passage points 520, 521, 522, 523 of the needling head 530. For reasons of clarity, only a few points are visible in the figures, however the number of passage points is not limited to these four points. In addition, the position of these points visible on the figure 5B does not mean that point 520 (or point 522) is determined first before point 521 (or point 523). Generally, the order of determining the different head passage points follows the unwinding and needling of the textile strip on the support tool.

[0063] The passage points 521, 522, 523 are determined as a function of the positions of the fibers along the X, Y, Z axes, in particular along the Z axis in the textile preform to be produced 500, of the local geometry of the preform 500, for example of its local radius of curvature, and of the minimum distance d min . This minimum distance d min is a distance making it possible to avoid a collision between the needling head 530 and the preform 500 being produced or the support tool 505. The minimum distance d min is predetermined by the user. This step 410 is shown in the figure 5B .

[0064] The number of passage points 520, 521, 522, 523 may depend on the complexity of the preform to be produced 500. For example, if the preform is of complex shape (for example, a non-axisymmetric shape), the number of passage points will generally be greater than a preform of simple shape (for example, an axisymmetric shape).

[0065] Then the method 400 comprises the determination 420 of the angular orientation of the needling head 530 for each passage point 520, 521, 522, 523 determined in the step 410 as a function of the angular orientation of the fibers in Z in the textile preform to be produced 500. This step 420 is represented on the figure 5C . In this step 420, for example, the angle α formed between the needling head 530 and the Z axis for the passage point 520 and / or the angle β formed between the needling head 530 and the X axis for the passage point 520 is determined. More particularly, in the example of determining the angle α, the angle α is formed between the Z axis and the orientation of the head, which corresponds to the orientation 560 of the fibers in Z for this passage point 520.

[0066] The method 400 may also comprise a step 409 of producing a mesh 510 of the geometry of the textile preform to be produced 500. The determination 410 of the set of coordinate triplets (x, y, z) of the passage points is thus carried out on this mesh 510. This step 409 is represented on the figure 5A This makes it possible to simplify the geometry of the preform 500 and to more easily determine the passage points 520.

[0067] When the support tool 505 rotates around an axis of rotation 580, the method 400 may further comprise a step 421 of projecting the waypoints 520 determined in step 410 into a reference plane 540 fixed or mobile relative to the support tool 505 and comprising the axis of rotation 580 of the support tool 505. The reference plane 540 may for example be the plane (YZ) or the plane (XY) or even the plane (λ). This makes it possible to determine the polar coordinates (r, θ, z) of the waypoints 520. This step 421 is represented on the figure 5D .

[0068] The method 400 may also comprise determining a local speed of movement of the needling head 530 as a function of the fiber rate in Z in the associated zone of the preform to be produced 500 as a function of a possible movement of the support tool 505. For example, if the support tool 505 is rotating during needling, depending on the radius of curvature of the geometry of the preform to be produced 500, it may be advantageous to vary the speed of movement of the needling head 530 between the points of passage 520 along this radius of curvature to best adapt the fiber rate of Z.

[0069] There figure 6 represents a flowchart of the method 600 for manufacturing a textile preform by needling according to one embodiment of the invention.

[0070] The method 600 firstly comprises the determination 610 of a program for moving and orienting a needling head according to the invention, therefore for example according to the method described previously, then the manufacturing 620 by needling the textile preform on a support tool. The support tool has the same shape as the internal surface of the preform to be produced. The needling is carried out using a needling head programmed according to the program determined in step 601.

[0071] A needling system used for manufacturing is for example a system comprising: a needling head programmed according to the determined program; a robotic arm movable according to several degrees of freedom, carrying the needling head and configured so as to move the needling head along predetermined trajectories and orientations in the movement and orientation program; a device for feeding a textile strip mounted on the needling head and configured to deposit the textile strip on a support tool and to cut it, and a control unit configured to control the robotic arm, the actuation of the needling head and the deposit of the textile strip according to the movement and orientation program of the head.

[0072] The support tooling used to determine the movement and orientation program of the needling head and for the manufacture of the textile preform may have a non-axisymmetric and / or non-opening shape. This makes it possible to produce a preform of non-axisymmetric and / or non-opening shape, which may, for example, form a preform for thermal protection against atmospheric re-entry.

[0073] The support tooling can also rotate, in both directions around a rotation axis, during needling, in order to facilitate the movements of the robotic arm. The control unit can, in this case, control the rotation of the support tooling. For example, it can control the rotation axis and / or the rotation speed of the support tooling.

[0074] The expression "between ... and ..." must be understood as including the limits.

Claims

1. Method (400) for determining a program for moving and orienting a needling head (530) for producing a textile preform (500) by needling a textile strip onto a support tool (505), comprising at least: - determining (410) a set of triplets of coordinates (x, y, z), (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) of the passage points (520, 521, 522, 523) of the needling head (530) as a function of the positions of the fibers along the Z axis in the textile preform to be produced (500), its local geometry and a minimum distance (d min) predetermined to be respected between the needling head and the support tool (505) or the preform making it possible to avoid a collision with the latter, and - the determination (420) of the angular orientation (α, β, γ) of the needling head for each passage point as a function of the angular orientation of the textile strip and of the Z-shaped fibers in the textile preform to be produced, the method further comprising the determination of a local movement speed of the needling head as a function of the Z-shaped fiber rate in the associated zone of the textile preform to be produced and of a rotation of the support tool.

2. Method according to claim 1, in which the support tool is rotating around an axis of rotation (580) and the method comprises a mathematical projection (421) of the determined passage points in a reference plane (540, λ) fixed or mobile relative to the support tool and comprising the axis of rotation.

3. Method according to any one of claims 1 or 2, further comprising the production (409) of a mesh (510) of the geometry of the textile preform to be produced, the determination of the set of coordinate triplets (x, y, z) being carried out on this mesh.

4. Method according to any one of claims 1 to 3, in which the support tool has a non-axisymmetric and / or non-opening shape.

5. Method for manufacturing (600) a textile preform by needling comprising the determination (610) of a program for moving and orienting a needling head according to one of claims 1 to 4 and the manufacturing by needling (620) of the textile preform on a support tool, the shape of which corresponds to that of the textile preform to be produced, using a needling head programmed according to the determined program.

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