System for positioning a woven preform tracer

Abstract

A system (1) for positioning strands (2) is disclosed, the strands comprising fibers of a first woven preform material (3), the preform (3) comprising strands (4) of fibers made of a second material on its surface, and strands (2) comprising fibers made of the first material forming tracers. The system (1) comprises: - a camera (5); - a light source (6) emitting an unpolarized incident beam (f1) capable of being guided toward the preform (3); - a polarizer (7) for positioning strands (2) comprising fibers of a first material forming tracers. The oscillator is able to polarize the unpolarized incident beam (f1) before it interacts with the preform (3) to obtain a polarized incident beam (f2); - cross analyzer (8); the first material is selected from glass, aramid and alumina; the second material is selected from carbon and silicon carbide; the camera (5) is able to capture the reflected beam (f3) from the interaction of the polarized incident beam (f2) with the preform (3), which has previously passed through the cross analyzer (8) to locate the tracer of the preform (3).

Description

Technical Field

[0001] This invention relates to the general field of composite material components. Background Technology

[0002] Typically, composite components include a reinforcement (e.g., a fiber reinforcement) and a matrix (e.g., a polymer resin).

[0003] The manufacturing process for this component involves various operations.

[0004] First, the operation known as “weaving” involves flat-weaving fiber strands (such as carbon fiber strands) into a flat preform using a loom. The preform is intended to form a reinforcement for the composite component.

[0005] Second, the operation known as “cutting” involves using a cutting die to cut flat preforms.

[0006] Third, the operation known as “forming” involves using forming molds to shape the flat preform in three dimensions.

[0007] Fourth, the operation known as "injection" involves injecting the matrix into an injection mold in which preforms are arranged along three dimensions to obtain a composite part.

[0008] During the weaving process, it is known to incorporate at least one strand comprising light-colored material fibers (e.g., glass fibers) that form a tracer; in other words, a reference that can be used throughout the manufacturing process. When the tracer comprises glass fibers, the tracer is visually identifiable by the white color of the glass fibers. Typically, the preform includes multiple tracers.

[0009] As mentioned above, the tracer is known to be used as a reference in the manufacturing process. For example, the tracer can be used to position preforms relative to a mold.

[0010] In cases where a preform is manually positioned and a tracer is placed in an area not directly visible to the operator, it is known to use a camera to capture the desired area and a screen to display the captured image in real time for ergonomic reasons. To position the preform relative to the mold, the operator must use the screen to position the tracer relative to a reference frame.

[0011] However, in practice, it was found that although the glass fiber was white, operators could not properly distinguish the tracers on the screen. In fact, the optical properties of carbon (specular reflection) greatly reduced the whiteness of the glass fiber.

[0012] Therefore, in practice, operators do not use a screen and position the tracer of the prefab roughly relative to a reference frame. This positioning greatly increases the number of defective prefabs and fails to ensure the traceability of the prefabs.

[0013] Therefore, the object of the present invention is to provide a simple, effective and economical solution to the above-mentioned problems. Summary of the Invention

[0014] Therefore, the present invention provides a system for positioning at least one strand of a woven preform of a component made of a composite material, the at least one strand comprising fibers made of a first material, the preform comprising strands of fibers made of a second material on its surface and at least one strand comprising fibers made of the first material forming a tracer, the system comprising a camera;

[0015] The system is characterized by further comprising:

[0016] - A light source that emits a non-polarized incident beam suitable for being guided toward the preform;

[0017] - A polarizer having a first polarization direction, the polarizer being adapted to polarize the unpolarized incident beam before it interacts with the preform to obtain a polarized incident beam.

[0018] - A cross-analyzer with a second polarization direction;

[0019] The first material is selected from glass, aramid, and alumina;

[0020] The second material is selected from carbon and silicon carbide;

[0021] The camera is adapted to capture the reflected beam generated by the interaction of a polarized incident beam with the preform, which has previously passed through a cross-analyzer to locate tracers on the preform.

[0022] This system makes it easy to locate tracers of prefabricated parts based on images captured by a camera, for example, to position or control the prefabricated parts. This system thus enables a significant reduction in the number of defective prefabricated parts, thereby reducing the number of defective components.

[0023] In practice, the system utilizes the difference in optical properties between the first and second materials to highlight the fibers made of the first material in an image captured by the camera. Therefore, the camera can only capture the light reflected from the fibers of the tracer made of the first material.

[0024] This system also enables the traceability of prefabricated components, and more generally, the traceability of composite material components.

[0025] The system according to the invention may include one or more of the following features and / or steps, either individually or in combination:

[0026] - The system includes a diffuser through which an unpolarized incident beam passes before passing through a polarizer;

[0027] -The system includes a screen that displays images captured by the camera in real time;

[0028] - The system includes a control unit configured to automatically process images captured by the camera;

[0029] - The light source includes multiple light-emitting diodes;

[0030] - The first material is glass or aramid, and the second material is carbon.

[0031] The present invention also relates to a method for positioning a woven preform of a composite material component relative to a mold via a system as described above, the preform comprising on its surface at least one strand (including fibers made of a first material forming tracers) and strands of fibers made of a second material, the first material being selected from glass, aramid, and alumina, and the second material being selected from carbon and silicon carbide, the method comprising the following steps:

[0032] a) Position the preform relative to the mold using a tracer positioned relative to a reference frame, based on images captured by a camera.

[0033] The positioning method according to the present invention may include one or more of the following features and / or steps, which may be used individually or in combination with each other:

[0034] - Step a) is performed by the operator using a screen that displays images captured by the camera in real time;

[0035] - The reference frame is formed by a slit that leads to a recess in the mold where a preform is arranged, and an unpolarized incident beam of light from the light source is guided toward the preform through the slit.

[0036] - The positioning method is implemented in the following operations: cutting the preform in a cutting mold and / or three-dimensional forming of the preform in a forming mold and / or injecting the substrate into an injection mold in which the preform is arranged.

[0037] The present invention also relates to a method for controlling a woven preform of a composite material component via a system as described above, the preform comprising on its surface at least one strand (including fibers made of a first material forming tracers) and strands of fibers made of a second material, the first material being selected from glass, aramid, and alumina, and the second material being selected from carbon and silicon carbide, the method comprising the following steps:

[0038] a) Control the tracer of the prefabricated component to be within a predetermined interval from the image captured by the camera.

[0039] The control method according to the present invention may include one or more of the following features and / or steps, which may be used individually or in combination with each other:

[0040] - Step a) is performed by a control device configured to automatically process images captured by the camera;

[0041] - The control method is implemented during the following operations: cutting the preform in a cutting mold and / or three-dimensional forming of the preform in a forming mold and / or injection operation of injecting the substrate into an injection mold in which the preform is arranged. Attached Figure Description

[0042] The invention will be better understood from the following description by way of non-limiting example and with reference to the accompanying drawings, in which other details, features and advantages of the invention will become clearer:

[0043] [ Figure 1 ] Figure 1 This is a schematic diagram of the system according to the present invention;

[0044] [ Figure 2 ] Figure 2 Perspective view of the blade prefabrication component;

[0045] [ Figure 3 ] Figure 3 For use in forming Figure 2 A perspective view of the mold for the blade preform shown;

[0046] [ Figure 4 ] Figure 4 To install Figure 3 A perspective view of the wedge-shaped part on the mold shown;

[0047] [ Figure 5 ] Figure 5 Perspective view of the prefabricated shell component;

[0048] [ Figure 6 ] Figure 6 For use in forming Figure 5 A perspective view of the mold for the precast housing shown;

[0049] [ Figure 7 ] Figure 7 For images obtained by a system according to the prior art;

[0050] [ Figure 8 ] Figure 8 An image obtained using the system according to the present invention. Detailed Implementation

[0051] Figure 1A system 1 is schematically shown for positioning at least one strand 2 of a woven preform 3 of a composite material component, the at least one strand comprising fibers (forming tracers) made of a first material.

[0052] For example, composite material components are part of aircraft turbines, such as fan blades or fan housings.

[0053] Composite components include reinforcements in the form of woven fiber preforms 3, 3a, and 3b, and an organic matrix such as a polymer resin.

[0054] This component is manufactured according to a manufacturing method that includes various operations.

[0055] First, the weaving operation involves weaving the fiber strands into a flat preform using a loom. Then, the woven preform consists of warp strands (i.e., strands extending along the length of the preform) and weft strands (i.e., strands extending along the width of the preform).

[0056] For example, prefabricated components are woven using a jacquard loom.

[0057] Advantageously, the weaving of the prefabricated components is three-dimensional weaving.

[0058] Second, the cutting operation includes cutting flat preforms using a cutting die.

[0059] Third, the molding operation involves using molding dies to shape the flat preform in three dimensions.

[0060] The molding die has a recessed portion, the shape of which roughly corresponds to the shape of the part to be produced.

[0061] Fourth, the injection operation involves injecting a matrix (e.g., a polymer resin) into an injection mold in which a three-dimensional preform is arranged.

[0062] Advantageously, the injection operation is achieved via a known method of "Resin Transfer Molding" (RTM). This RTM method uses an injection mold comprising two opposing housings movable relative to each other. Each housing includes a recess that defines a cavity for placing the preform and the injection substrate.

[0063] Advantageously, the different operations of the manufacturing method are performed in the order defined above. The different operations of the manufacturing method can be performed manually and / or automatically.

[0064] Preforms 3, 3a, and 3b include on their surfaces at least one strand 2 (including fibers made of a first material forming tracers) and strands 4 of fibers made of a second material. The tracers correspond to references (or markings) that can be used throughout the manufacturing process of the parts to, for example, position or control the preforms 3, 3a, and 3b during operation.

[0065] The first material is selected from glass, aramid, and alumina. The second material is selected from carbon and silicon carbide.

[0066] Advantageously, for ease of identification of the tracer, the fibers made of the first material are light-colored, and the fibers made of the second material are dark-colored.

[0067] In the first preferred combination, the first material is glass, and the second material is carbon. Typically, carbon fiber is black, while glass fiber is white.

[0068] In the second preferred combination, the first material is aramid fiber and the second material is carbon. Typically, carbon fiber is black, while aramid fiber is yellow.

[0069] In the third preferred combination, the first material is silicon carbide, and the second material is aluminum oxide. Typically, silicon carbide fibers are black, while aluminum oxide fibers are yellowish-white.

[0070] For easy identification, the tracers are located on the surfaces of preforms 3, 3a, and 3b.

[0071] As an example, the tracer may comprise two-thirds fibers made of a first material and one-third fibers made of a second material. The tracer may also comprise 100% fibers made of the first material.

[0072] Preforms 3, 3a, and 3b may of course include multiple tracers. Advantageously, during the weaving operation, the tracers are integrated into preforms 3, 3a, and 3b.

[0073] The tracer can be a warp strand (hereinafter referred to as a warp tracer or longitudinal tracer) or a weft strand (hereinafter referred to as a weft tracer or transverse tracer).

[0074] According to the present invention, a system 1 for positioning at least one tracer for woven preforms 3, 3a, 3b includes:

[0075] - Camera 5;

[0076] - Light source 6, which emits a non-polarized incident beam f1 adapted to be guided toward preforms 3, 3a, 3b;

[0077] - Polarizer 7, which has a first polarization direction, is adapted to polarize the unpolarized incident beam f1 before it interacts with the preforms 3, 3a, 3b to obtain a polarized incident beam f2.

[0078] - Cross-analyzer 8, which has a second polarization direction.

[0079] Camera 5 is adapted to capture the reflected beam f3 generated by the interaction of the polarized incident beam f2 with the preforms 3, 3a, and 3b. The reflected beam f3 has previously passed through the cross analyzer 8 in order to locate the tracers of the preforms 3, 3a, and 3b.

[0080] This system 1 allows for easy positioning of one or more tracers in the preform. One or more tracers appear clearly in the image captured by camera 5. System 1 also enables the color of the fibers made of the first material to be significantly highlighted in the image captured by camera 5.

[0081] To this end, system 1 utilizes the difference in optical properties between the first and second materials to highlight the fibers made of the first material in the image captured by camera 5. The second material exhibits specular reflection, while the first material exhibits diffuse reflection. Unlike diffuse reflection, specular reflection has the special property of maintaining polarization. Therefore, the cross-analyzer 8 enables the blocking of light reflected by the fibers made of the second material and enables the passage of only the light reflected by the fibers made of the first material from the tracer, so that the fibers made of the first material appear clearly in the image captured by camera 5. In other words, camera 5 only captures the light reflected by the fibers made of the first material from the tracer.

[0082] Polarizer 7 has a first polarization direction (or a first transmission direction), which enables the incident beam to be linearly (or linearly) polarized along the first polarization direction. Therefore, this polarizer 7 is called a "linear polarizer" or "linear polarizer".

[0083] Advantageously, the cross analyzer 8 has a second polarization direction (or a second transmission direction) that is perpendicular to or substantially perpendicular to the first polarization direction of the polarizer 7, thus the analyzer 8 crosses the polarizer 7. The polarization direction is defined in a plane perpendicular to the beam propagation direction.

[0084] Advantageously, system 1 includes a diffuser (not shown) through which the unpolarized incident beam f1 passes before passing through polarizer 7. This diffuser enables uniform illumination.

[0085] System 1 may include a screen 9 on which images captured by camera 5 are displayed in real time. For example, such screen 9 may enable an operator to locate a tracer in order to position or control a prefabricated component.

[0086] System 1 may include a control device configured to control the light source 6 and the camera 5. If the system includes a screen 9, the control device may also be configured to control the screen 9. The control device may be configured to automatically process images captured by the camera 5. To automatically process images captured by the camera 5, the control device may include, for example, a computer (or information processing system) and image processing software.

[0087] Advantageously, images captured by camera 5 are recorded to ensure the traceability of prefabricated parts, and more generally, the traceability of composite material parts obtained through manufacturing methods.

[0088] Advantageously, camera 5 has a variable field of view, which is set to cover the desired field of view.

[0089] Advantageously, the light source 6 includes multiple light-emitting diodes (LEDs). For example, the light-emitting diodes are in the form of LED strips.

[0090] The present invention also relates to a method for positioning woven preforms 3, 3a, 3b relative to molds 11a, 11b via system 1, the preforms 3, 3a, 3b comprising at least one strand 2 (including fibers made of a first material forming tracers) and strands 4 of fibers made of a second material on their surfaces.

[0091] The positioning method includes step a), which includes positioning tracers of preforms 3, 3a, 3b relative to a reference system and positioning preforms 3, 3a, 3b relative to molds 11a, 11b based on images captured by camera 5.

[0092] Step a) of the positioning method can be performed by the operator using the screen 9 of the system 1, on which the image captured by the camera 5 is displayed in real time.

[0093] Step a) of the positioning method can be executed automatically, in particular, by the control device of System 1.

[0094] The positioning method can be implemented throughout the manufacturing process of the composite material part, particularly during the cutting and / or molding and / or injection operations.

[0095] The present invention also relates to a method for controlling the weaving of preforms 3, 3a, 3b by system 1, the preforms 3, 3a, 3b comprising at least one strand 2 (including fibers made of a first material forming tracers) and strands 4 of fibers made of a second material on their surfaces.

[0096] The control method includes step a), which controls the tracers of prefabricated parts 3, 3a, and 3b to be within a predetermined interval from the image captured by camera 5.

[0097] Step a) of the control method can be performed by the operator using the screen 9 of the system 1, on which the image captured by the camera 5 is displayed in real time.

[0098] Step a) of the control method can be executed by the control device of system 1, which is configured to automatically process the images captured by camera 5.

[0099] The control methods can be implemented throughout the entire manufacturing process of the composite material part, particularly during the cutting and / or molding and / or injection operations.

[0100] Figures 2 to 4 The molding operation of the preform 3a of the fan blade is shown.

[0101] Figure 2 A planar impeller preform 3a is shown, which is suitable for use Figure 3 and Figure 4 The molding die 11a shown is formed in three dimensions.

[0102] like Figure 2 As shown, the impeller preform 3a includes a portion 13 adapted to form the impeller root, hereinafter referred to as "root portion 13". The impeller preform 3a also includes a portion 14 adapted to form the impeller blade, hereinafter referred to as "blade portion 14". Finally, the impeller preform 3a includes a joint 15 between the root portion 13 and the blade portion 14, the joint 15 being adapted to form a blade support surface.

[0103] Specifically, the blade preform 3a includes a lower transverse tracer 2a on the surface of the joint 15.

[0104] like Figure 3 and Figure 4 As shown, the molding die 11a includes a recess 16 for three-dimensionally forming the blade preform 3a. More specifically, the recess 16 includes an extension 17 adapted to form a root portion 13 in three dimensions, hereinafter referred to as "root extension 17". The recess 16 also includes an extension 18 adapted to three-dimensionally form a blade portion 14, hereinafter referred to as "blade extension 18". Finally, the recess 16 includes an extension 19 adapted to form a joint portion 15 in three dimensions, hereinafter referred to as "joint extension 19".

[0105] The forming mold 11a also includes a slit 12 that leads to the lower surface of the mold 11a and the recess 16. The slit 12 is located at the engagement extension 19 and forms a reference system specifically for positioning the blade preform 3a relative to the mold 11a.

[0106] The forming mold 11a also includes a wedge 21 adapted to attach to two protruding supports 22 that engage with the recess 16 at the root extension 17. The wedge 21 enables the root portion 13 and the joint 15 of the blade preform 3a to be secured by clamping.

[0107] like Figure 3 As shown, for this molding operation, system 1 includes screen 9, on which images captured by camera 5 are displayed in real time. An incident beam f1 from light source 6 is guided through slit 12 of mold 11a toward the blade preform 3a placed in recess 16.

[0108] During the molding process, the above positioning method is implemented to position the blade preform 3a relative to the molding die 11a.

[0109] The operator uses screen 9 of system 1 to manually position the lower lateral tracer 2a of the blade preform 3a in the slit 12 that forms the reference system, on which an image captured by camera 5 is displayed in real time. To do this, the operator uses screen 9 to move the blade preform 3a on mold 11a until the lower lateral tracer 2a is included in the slit 12.

[0110] It should be noted that the blade preform 3a is positioned relative to the forming mold 11a not only by positioning the lower lateral tracer 2a in the slit 12, but also by aligning the upper lateral tracer (not shown) of the blade preform 3a with a reference projected onto the mold 11a by one or more lasers. For example, the upper lateral tracer is arranged at the joint 15. The reference projected by one or more lasers defines the theoretical position of the upper lateral tracer. After the blade preform 3a is positioned, the operator secures the root portion 13 and the joint 15 of the blade preform 3a by attaching the wedge 21 to the two supports 22 of the mold 11a. The root portion 13 and the joint 15 are then pressed between the recess 16 and the wedge 21.

[0111] During the molding operation, the above control method is implemented to control the position of the blade preform 3a after its positioning, in other words, the position after the wedge 21 is placed on the two supports 22.

[0112] In fact, with the help of the screen 9 of the system 1, the operator controls the lateral tracer 2a to be exactly within the interval defined by the slit 12, and the image captured by the camera 5 is displayed in real time on the screen.

[0113] It should be noted that the blade preform 3a is formed here by the operator, who unfolds the preform 3a into the recess 16 until the upper longitudinal tracer (not shown) of the preform 3a coincides with a reference projected onto the mold 11a by one or more lasers. The reference projected by one or more lasers defines the theoretical position of each upper longitudinal tracer.

[0114] Figure 5 and Figure 6 The molding process of preform 3b of the fan housing is shown.

[0115] Figure 5 A planar shell preform 3b is shown, which is suitable for use Figure 6 The molding die 11b shown is formed in three dimensions.

[0116] like Figure 5 As shown, the housing preform 3b is in the form of a rectangular sheet. In particular, the housing preform 3b includes at least one upper longitudinal tracer 2b on its surface.

[0117] like Figure 6 As shown, the molding die 11b includes a cylindrical recess 23 for three-dimensionally forming the shell preform 3b. The die 11b is rotatable about a rotation axis X that passes through the axis of rotation of the cylindrical recess 23.

[0118] like Figure 6 As shown, for this molding operation, system 1 includes a control device 10 configured to automatically process images captured by camera 5. System 1 also includes a screen 9 on which the images captured by camera 5 are displayed in real time. An incident light beam f1 from light source 6 is guided toward the housing preform 3b placed on recess 23.

[0119] It should be noted that the housing preform 3b is formed here by the operator, who wraps the preform 3b around the recess 23 by aligning the upper longitudinal tracer 2b of the preform 3b with a reference projected onto the mold 11b by one or more lasers. The reference projected by one or more lasers defines the theoretical position of the upper longitudinal tracer 2b.

[0120] During the molding process, the above control methods are implemented to control the molding of the shell preform 3b.

[0121] The control device 10 automatically controls the upper longitudinal tracer 2b within a predetermined range. To do this, the control device 10 compares the actual position of the upper longitudinal tracer 2b with a predetermined interval. For example, the actual position of the upper longitudinal tracer 2b is determined based on images captured by the camera 5 and image processing software.

[0122] In this application, the terms “lower” and “upper” associated with preforms 3a, 3b and molds 11a, 11b are defined relative to the position of the molds in the figure.

[0123] Figure 7 The image is of a preform sample 3 taken by a camera according to a system based on the prior art. The preform sample includes a longitudinal tracer and two transverse tracers.

[0124] Figure 8 The images are of the same preform sample 3 taken by camera 5 of system 1 according to the present invention.

[0125] As can be seen, the system 1 according to the invention enables the white of the tracer to be highlighted significantly, thus making it easy to position the tracer of the preform 3 for purposes such as positioning or controlling the preform 3.

Claims

1. A method for positioning woven preforms (3, 3a, 3b) of composite material components relative to molds (11a, 11b) via a system (1), the woven preforms (3, 3a, 3b) comprising on their surface at least one strand (2) and strands (4) of fibers made of a second material, the at least one strand comprising fibers made of a first material forming tracers (2a, 2b), the first material being selected from glass, aramid, and alumina, and the second material being selected from carbon and silicon carbide, the system (1) comprising: - Camera (5); - A light source (6) that emits a non-polarized incident beam (f1) adapted to be directed toward the woven preform (3, 3a, 3b). - A polarizer (7) having a first polarization direction, the polarizer (7) being adapted to polarize the unpolarized incident beam (f1) before it interacts with the woven preform (3, 3a, 3b) to obtain a polarized incident beam (f2). - Cross-analyzer (8), the cross-analyzer having a second polarization direction; and The camera (5) is adapted to capture a reflected beam (f3) generated by the interaction of the polarized incident beam (f2) with the woven preform (3, 3a, 3b), the reflected beam (f3) having previously passed through the cross analyzer (8) to locate the tracers (2a, 2b) of the woven preform (3, 3a, 3b). The method includes the following steps: a) The woven preforms (3, 3a, 3b) are positioned relative to the molds (11a, 11b) by means of the tracer (2a, 2b) positioned relative to the reference frame.

2. The method according to claim 1, characterized in that, Step a) is performed by the operator using a screen (9) on which images captured by the camera (5) are displayed in real time.

3. The method according to claim 1 or 2, characterized in that, The reference frame is formed by a slit (12) leading to a recess (16) of the woven preform arranged in the mold, and the unpolarized incident beam (f1) of the light source (6) is guided toward the woven preform via the slit (12).

4. The method according to claim 1 or 2, characterized in that, The method is carried out in the following operations: cutting the woven preforms (3, 3a, 3b) in a cutting mold and / or three-dimensional forming the woven preforms (3, 3a, 3b) in a forming mold and / or injection operations of injecting the substrate into an injection mold in which the woven preforms (3, 3a, 3b) are arranged.

5. A method for controlling a woven preform (3, 3a, 3b) of a composite material component via a system (1), the woven preform (3, 3a, 3b) comprising on its surface at least one strand (2) and strands (4) of fibers made of a second material, the at least one strand comprising fibers made of a first material forming tracers (2a, 2b), the first material being selected from glass, aramid, and alumina, and the second material being selected from carbon and silicon carbide, the system (1) comprising: - Camera (5); - A light source (6) that emits a non-polarized incident beam (f1) adapted to be directed toward the woven preform (3, 3a, 3b). - A polarizer (7) having a first polarization direction, the polarizer (7) being adapted to polarize the unpolarized incident beam (f1) before it interacts with the woven preform (3, 3a, 3b) to obtain a polarized incident beam (f2). - Cross-analyzer (8), the cross-analyzer having a second polarization direction; and The camera (5) is adapted to capture a reflected beam (f3) generated by the interaction of the polarized incident beam (f2) with the woven preform (3, 3a, 3b), the reflected beam (f3) having previously passed through the cross analyzer (8) to locate the tracers (2a, 2b) of the woven preform (3, 3a, 3b). The method includes the following steps: a) Control the tracers (2a, 2b) of the woven preforms (3, 3a, 3b) to be within a predetermined interval from the image captured by the camera (5).

6. The method according to claim 5, characterized in that, Step a) is performed by a control device (10) configured to automatically process images captured by the camera (5).

7. The method according to claim 5 or 6, characterized in that, The method is carried out in the following operations: cutting the woven preforms (3, 3a, 3b) in a cutting mold and / or three-dimensional forming the woven preforms (3, 3a, 3b) in a forming mold and / or injection operations of injecting the substrate into an injection mold in which the woven preforms (3, 3a, 3b) are arranged.

8. A component comprising: A woven preform (3, 3a, 3b) of a composite material component, the woven preform (3, 3a, 3b) comprising on its surface at least one strand (2) and strands (4) of fibers made of a second material, the at least one strand comprising fibers made of a first material forming tracers (2a, 2b), the first material being selected from glass, aramid and alumina, and the second material being selected from carbon and silicon carbide; as well as A system (1) for positioning tracers (2a, 2b) of woven preforms (3, 3a, 3b), the system (1) comprising: - Camera (5); - A light source (6) that emits a non-polarized incident beam (f1) adapted to be directed toward the woven preform (3, 3a, 3b). - A polarizer (7) having a first polarization direction, the polarizer (7) being adapted to polarize the unpolarized incident beam (f1) before it interacts with the woven preform (3, 3a, 3b) to obtain a polarized incident beam (f2). - Cross-analyzer (8), the cross-analyzer having a second polarization direction; and The camera (5) is adapted to capture a reflected beam (f3) generated by the interaction of the polarized incident beam (f2) with the woven preform (3, 3a, 3b), the reflected beam (f3) having previously passed through the cross analyzer (8) to locate the tracers (2a, 2b) of the woven preform (3, 3a, 3b).

9. The component according to claim 8, characterized in that, The system (1) includes a diffuser through which the unpolarized incident beam (f1) passes before passing through the polarizer (7).

10. The component according to claim 8, characterized in that, The system (1) includes a screen (9) on which images captured by the camera (5) are displayed in real time.

11. The component according to claim 8, characterized in that, The system (1) includes a control device (10) configured to automatically process images captured by the camera (5).

12. The component according to claim 8, characterized in that, The light source (6) includes multiple light-emitting diodes.

13. The component according to claim 8, characterized in that, The first material is glass or aramid, and the second material is carbon.

Images