Reproducible shaping of a fibrous blank

Abstract

Reproducible shaping of a fibrous blank. The invention relates to a method for shaping a fibrous blank (200) comprising warp (101a) and weft (102a, 102b, 102c) marker yarns, comprising: - projecting a warp visual marker (501a) onto the blank (200), - deforming the blank (200) from the bottom of the blade blank to the top of the blade blank so as to align the warp marker yarn (101a) with its visual marker (501a), - projecting a weft visual marker yarn (502a, 502b, 502c) onto the blank (200), - deforming the blank (200) from the warp marker yarn (101a) to the first and second edges of the blank. (200) so as to match the weft tracer thread (102a, 102b, 102c) with its visual marker (502a, 502b, 502c). Figure for the abbreviation: Fig. 9

Description

Title of the invention: Reproducible shaping of a fibrous blank Technical field

[0001] The invention relates to the manufacture of blades or propellers from composite material comprising a fibrous reinforcement produced by three-dimensional weaving and densified by a matrix. Prior art

[0002] The use of composite materials for the manufacture of blades or propellers, for example for gas turbine blades for aeronautical engines or for industrial turbines, makes it possible to obtain parts having mechanical performances equivalent to or even superior to those made of metal, while having a much lower mass.

[0003] The manufacture of these blades or propellers can begin by producing a single-piece fiber blank by three-dimensional weaving, which will then be shaped so as to obtain a fiber preform of the blade or propeller to be manufactured. The fiber preform is then densified by a matrix to obtain the part. An example of a method for manufacturing a blade or propeller made of composite material is for example described in document FR3046564 or in document FR3046563.

[0004] The fiber blank comprises two types of yarns forming a network: the warps (which extend along the weaving direction) and the wefts (which extend transversely to the weaving direction). The warps are substantially parallel to each other and the wefts are substantially parallel to each other. Warps and wefts generally intersect at a substantially right angle, thus forming a substantially orthogonal warp-weft network.

[0005] However, the shape of the blades or propellers to be manufactured is not developable. Thus, when the fiber blank is deformed to obtain a fiber preform, a loss of orthogonality of the warp-weft network can be observed locally. This loss of orthogonality is called the offset. The angle measuring the difference between the offset position of a weft thread and its original position is called the "offset angle".

[0006] However, the greater the offset angle, the more the mechanical properties of the fiber preform thus obtained will be modified. In tension and compression, a so-called offset material is more flexible in the weft direction and more rigid in the warp direction. A significant offset will therefore result in a relatively significant loss of mechanical properties in the weft direction. Thus, it will be necessary to manufacture a fiber preform that is thicker than it would be without offset, which involves a significant addition of mass for the performance of the turbine or engine.

[0007] The step of deforming the fiber blank into a fiber preform can be carried out using visual markers, making it possible to control the arrangement of certain weft or warp threads. Such a method is for example described in document US2016288380A1. However, this step of deforming the fiber blank into a fiber preform is carried out by hand without an ordered shaping sequence, which results in a high variability in the location of the areas where there is misalignment from one part to another. Finally, a high variability in the mechanical properties is obtained from one part to another, and different geometries in the parts obtained after the step of injecting resin into the preform. Statement of the invention

[0008] The present invention aims to remedy the aforementioned drawbacks by proposing a predefined shaping sequence for the fiber blank, allowing suitable and reproducible deformation of the blank.

[0009] For this purpose, the invention proposes a method for shaping a fiber blank extending longitudinally in an X direction and transversely in a Y direction, obtained by three-dimensional weaving between a plurality of warp threads and a plurality of weft threads and intended to form a fiber preform for a turbomachine blade, the fiber blank comprising a root blank intended to form the blade root and a blade blank intended to form the blade blade, the fiber blank comprising a reference face extending in the Y direction between a first edge and a second edge intended to form the leading edge and the trailing edge of the blade, the fiber blank further comprising a warp tracer thread extending on the reference face in the X direction from the root blank and at least one weft tracer thread extending on the reference face in the Y direction between the first edge and the second edge,the method comprising at least: ,

[0010] - placing the fiber blank in a shaping mold so that that the reference face is visible,

[0011] - maintaining the foot blank in the shaping mold,

[0012] - the projection of at least one visual chain marker on the reference face of the fiber blank corresponding to a reference location of the warp tracer yarn,

[0013] - the deformation of the blade blank from the bottom of the blade blank to the top of the blade blank in the X direction so as to match the warp tracer wire with the warp visual mark,

[0014] - the projection of at least one visual frame marker onto the reference face of the fiber blank corresponding to a reference location of the weft tracer yarn,

[0015] - the deformation of the blade blank in the Y direction from the tracer wire of warp to the first edge and to the second edge of the blank so as to match the weft tracer thread with the visual weft mark.

[0016] Thus, the shaping process is predefined and identical between each operator. The deformation from the bottom to the top and from the center to the edges makes it possible in particular to obtain identical locations for the de-framing zones from one part to another, and therefore better anticipation of the zones with weaker mechanical properties in the weft direction.

[0017] According to a particular aspect of the invention, the fiber blank comprises a plurality of weft tracer yarns distributed between the bottom of the blade blank and the top of the blade blank and in which a plurality of visual weft markers corresponding to a reference location of the weft tracer yarns are projected, the following step being repeated for each weft tracer yarn in order from the bottom of the blade blank to the top of the blade blank:

[0018] - the deformation of the blade blank in the Y direction from the tracer wire of warp to the first edge and to the second edge of the blank so as to match the weft tracer thread with the corresponding weft visual mark,

[0019] so as to match all the weft tracer threads with the corresponding weft visual marker.

[0020] According to another particular aspect of the invention, the deformation of the blade blank in the Y direction is carried out from the warp tracer yarn to the first edge of the blank so as to make the weft tracer yarn correspond to a part of the weft visual mark, then from the warp tracer yarn to the second edge of the blank so as to make the weft tracer yarn correspond to the corresponding weft visual mark.

[0021] According to another particular aspect of the invention, the projection of the visual markers is carried out by laser.

[0022] According to another particular aspect of the invention, the visual marker corresponding to a tracer wire comprises a line of the same width as said tracer wire.

[0023] According to another particular aspect of the invention, the visual marker corresponding to a tracer wire comprises two lines delimiting an area corresponding to the reference location of said tracer wire.

[0024] According to another particular aspect of the invention, the fibrous blank is moistened before being deformed to facilitate its deformation.

[0025] The invention further relates to a method for manufacturing a turbomachine blade made of composite material, comprising:

[0026] - the production of a fiber blank by three-dimensional weaving of threads comprising a root blank intended to form the blade root and a blade blank intended to form the blade, the fibrous blank comprising a reference face extending between a first edge and a second edge intended to form the leading edge and the trailing edge of the blade, the yarns comprising a warp tracer yarn and at least one weft tracer yarn arranged at least on the reference surface,

[0027] - cutting the fiber blank while leaving intact the tracer threads located on the reference surface to obtain a trimmed fiber blank capable of taking the shape and dimensions of the constituent parts of the blade,

[0028] - shaping the fiber blank according to the shaping method according to the invention for obtaining a formed fiber preform,

[0029] - injecting a matrix precursor resin into the fiber preform in order to to impregnate the fiber preform,

[0030] - the transformation of the matrix precursor resin in the fiber preform into matrix so as to obtain a part made of composite material comprising a fibrous reinforcement densified by a matrix and having the shape and dimensions of the blade. Brief description of the drawings

[0031] [Fig-1] [Fig.l] is a schematic perspective view of a fiber pre-draft produced by three-dimensional weaving intended for the production of a fiber preform.

[0032] [Fig.2] [Fig.2] is a schematic perspective view of a fiber blank obtained after cutting the fiber pre-blank of [Fig.l].

[0033] [Fig.3] [Fig.3] is a schematic view of a blade obtained after shaping and densification of the fiber blank of [Fig.2].

[0034] [Fig.4] [Fig.4] is a schematic perspective view of a shaping mold and a laser projector according to one embodiment of the invention.

[0035] [Fig.5] [Fig.5] is a schematic perspective view of the fiber blank of [Fig.2] arranged without being deformed in the shaping mold of [Fig.4].

[0036] [Fig.6] [Fig.6] is a schematic perspective view of the fiber blank of [Fig.5] deformed so as to make the warp tracer yarn coincide with its visual reference.

[0037] [Fig.7] [Fig.7] is a schematic perspective view of the fiber blank of [Fig.6] deformed so as to make the first weft tracer thread coincide with its visual reference.

[0038] [Fig.8] [Fig.8] is a schematic perspective view of the fiber blank of [Fig.7] deformed so as to make the second weft tracer thread coincide with its visual reference.

[0039] [Fig.9] [Fig.9] is a schematic perspective view of the fiber blank of the [Fig.8] deformed so as to make all the tracer wires coincide with their visual reference. Description of the embodiments

[0040] The invention applies generally to the production of blades or propellers made of composite material for turbomachines, the blade comprising a fiber reinforcement densified by a matrix. The embodiments for a blade made of composite material will be described below. It is of course not outside the scope of the invention if the composite material part produced is a propeller.

[0041] The process for manufacturing a blade from a composite material begins with the production of a fiber blank obtained by three-dimensional weaving or by multi-layer weaving.

[0042] By "three-dimensional weaving" or "3D weaving" is meant here a weaving method by which at least some of the warp threads bind weft threads over several weft layers, such as for example an "interlock weave". By "interlock weave" is meant here a 3D weave weave in which each warp layer binds several weft layers with all the threads of the same warp column having the same movement in the plane of the weave. It will be noted, in general, that the roles of the warp and weft threads are interchangeable.

[0043] By "multi-layer weave" is meant here a three-dimensional weave with several weft layers whose basic weave of each layer is equivalent to a conventional 2D fabric weave, such as a plain, satin or twill weave, but with certain points of the weave which bind the weft layers together.

[0044] The production of the fiber blank by 3D weaving makes it possible to obtain a connection between the layers, and thus to have good mechanical strength of the fiber blank, and therefore of the blade made of composite material, in a single textile operation.

[0045] An example of the production of a fiber blank is now described. In this example, the weaving is carried out on a Jacquard type loom.

[0046] [Fig. 1] schematically shows the weaving of a fibrous pre-blank 100 from which a fibrous blank 200 ([Fig. 2]) can be extracted, making it possible to obtain, after shaping, a fibrous reinforcement preform for a blade or propeller of an aeronautical engine.

[0047] The fibrous pre-blank 100 is obtained by three-dimensional weaving, or 3D weaving, or by multi-layer weaving carried out in a known manner using a Jacquard type loom on which a bundle of warp threads or strands 101 has been arranged in a plurality of layers, the warp threads being linked by weft layers 102 also arranged in a plurality of layers. A substantially orthogonal warp-weft network is thus obtained. A detailed example of the production of a fibrous blank intended to form the fibrous reinforcement of a blade for an aeronautical engine from a 3D woven fibrous blank is notably described in detail in the documents US7101154, US7241112 and WO2010 / 061140.

[0048] The fibrous pre-blank 100 is woven in the form of a strip extending generally in a direction X corresponding to the longitudinal direction of the blade to be produced. The fibrous pre-blank 100 extends transversely in a direction Y, and in thickness in a direction Z perpendicular to the directions X and Y.

[0049] In the fiber pre-blank 100, the fiber blank 200 has a variable thickness determined as a function of the longitudinal thickness and the profile of the blade of the vane to be produced. In its part intended to form a root preform, the fiber blank 200 has a portion of excess thickness 203 determined as a function of the thickness of the root of the vane to be produced. The fiber blank 200 is extended by a portion of decreasing thickness 204 intended to form the base of the vane and then by a portion 205 intended to form the blade of the vane. The portion 205 has in the Y direction a profile of variable thickness between its edge 205a intended to form the leading edge of the vane and its edge 205b intended to form the trailing edge of the vane to be produced. The portion 205 extends in the Z direction between a first face 205c intended to form the intrados of the blade profile and a second face 205d intended to form the extrados of the blade profile.

[0050] The fibrous blank 200 is woven in a single piece. In the thickness variation portions of the fibrous blank, such as in the decreasing thickness portion 204, the reduction in thickness of the blank can be achieved by progressively removing weft layers during weaving. Once the weaving of the blank 200 in the pre-blank 100 is completed, the non-woven yarns are cut. The blank 200 illustrated in [Fig. 2] is then obtained and woven in a single piece.

[0051] As illustrated in [Fig.2], the fiber blank 200 comprises structure yarns 101 and 102, used for weaving the structure of the blank, and visually identifiable tracer yarns 101a, 102a, 102b and 102c. The tracer yarns 101a, 102a, 102b and 102c, incorporated during the weaving of the fiber pre-blank 100, are located essentially on the surface of the fiber blank 200. The tracer yarn 101a is a warp yarn. The tracer yarns 102a, 102b and 102c are weft yarns.

[0052] The tracer warp yarn 101a can be placed substantially equidistant from the edges 205a and 205b of the fiber blank intended to form the leading edge and the trailing edge of the blade or propeller to be manufactured.

[0053] [Fig. 3] illustrates the location of the tracer wires on the part manufactured by shaping the fiber blank and densification by a matrix of the preform thus obtained.

[0054] In the example shown in Figures 2 and 3, there is only one warp tracer thread and three weft tracer threads. It is of course not outside the scope of the invention if the number of weft tracer threads is less than or greater than three.

[0055] According to a particular embodiment of the invention, the structural threads may be carbon fibers, and the tracer threads may be glass fibers, Kevlar fibers or fibers made of a carbon-glass mixture. Thus, the tracer threads appear light in color against the rest of the blank, which is dark.

[0056] Furthermore, the presence of these tracer threads can make it possible to facilitate or standardize the cutting of the fiber pre-blank to obtain the fiber blank. Examples of using tracer threads to carry out such cutting are for example described in document US2015165571A1.

[0057] As illustrated in Figures 4 and 5, the fiber blank 200 is placed in a shaping mold 6 without being deformed. The shaping mold 6 has an imprint 60 having the shape of the desired fiber preform.

[0058] The fiber blank 200 is positioned in the shaping mold by placing the part 203 of the fiber blank intended to form the blade root in the part of the imprint 60 of the mold 6 intended to receive it.

[0059] According to a particular embodiment of the invention, the fibrous blank 200 thus arranged in the mold without being deformed can be moistened, for example with distilled water.

[0060] The root of the fiber blank 200 is then blocked or fixed in the mold 6, for example by means of a pre-compaction jaw 61. Blocking the root of the blank can cause the pre-compaction of said root and make it possible to block a portion of the fibers of the root in the desired position. By blocking the fiber blank by the root, and not by the portion intended to form the blade, a smooth transition is obtained between the blocked zone and the unblocked zone, in order to avoid buckling of the fibers located at the boundary between the blocked zone and the unblocked zone.

[0061] When the fiber blank is placed in the shaping mold 6, the blank can be placed in a configuration which deforms it by applying a rotation around an axis X parallel to the main direction while keeping the foot of the blank fixed, which has the consequence of twisting the blade of the blank around this axis.

[0062] In certain cases, it may also be provided that the shaping mold has a sliding movable part intended to be positioned against the free end of the foot of the blank in order to exert a stress achieving the desired deformation of this portion of the blank, or avoiding certain types of deformation in this part while a deformation is exerted on other portions of the blank.

[0063] Different systems for locating and positioning the blank can be used, in particular a laser projector 5 (see [Fig.4]) which projects a light beam at the ideal location of one or more tracer wires so that it is then easy to move the corresponding tracer wire accordingly to obtain the predetermined positioning. The light beam can be a laser of the same width as the tracer wire to which it corresponds. The light beam may be a laser projecting over a large width delimiting the reference zone of the tracer wire to which it corresponds. The light beam may be a split laser projecting two lines delimiting the reference zone of the tracer wire to which it corresponds.

[0064] The coincidence of the tracer threads of the fiber blank 200 with their visual reference is carried out in several stages in a well-defined order.

[0065] According to a first step illustrated in [Fig.6], the laser projector 5 begins by indicating at least the visual reference mark 501a of the warp tracer yarn. This visual reference mark 501a of the warp tracer yarn corresponds to the reference position of the warp tracer yarn 101a on the fiber preform shaped in the shaping mold. Thus, the fiber blank 200 must be deformed so as to make the warp tracer yarn 101a present on its face coincide with the visual reference mark 501a of the warp tracer yarn.

[0066] The fiber blank 200 is deformed from the bottom of the blade of the blank towards the top of the blade of the blank, that is to say in the direction X of the increasing abscissas, so as to superimpose the warp tracer yarn 101a of the blank 200 with the visual reference 501a of the warp tracer yarn.

[0067] By deforming the blank 200 from the bottom to the top, that is to say from the root of the blank to the upper edge of the blade of the blank, the offset is limited to the root and the bottom of the blade. Indeed, as the fiber blank 200 is deformed away from the blocked part, the offset becomes more and more significant. Since the material properties are usually less good at the root and at its junction with the blade, it is preferable to limit the offset to these locations, to transfer it to the top of the blade where the material characteristics are better and will allow a better tolerance to the offset. In addition, this deformation from the bottom of the blade of the blank 200 to the top of the blade of the blank 200 facilitates the repeatability of the deformation with a controlled arrangement of the offset zones.

[0068] According to a second step illustrated in [Fig.7], the laser projector 5 then indicates at least the visual reference mark 502a of the first weft tracer yarn starting from the bottom of the blade of the blank 200, that is to say the first weft tracer yarn in the direction X of the increasing abscissas. This visual reference mark 502a of the first weft tracer yarn corresponds to the reference position of the first weft tracer yarn 102a on the fiber preform shaped in the shaping mold. Thus, the fiber blank 200 must be deformed so as to make the first weft tracer yarn 102a present on its face coincide with the visual reference mark 502a of the first weft tracer yarn. Preferably, the laser projector 5 also indicates the visual reference mark 501a of the warp tracer yarn.

[0069] The fiber blank 200 is deformed from the warp tracer yarn 101a towards the edge 205a of the fiber blank 200 intended to form the leading edge of the blade, that is to say in the direction of increasing ordinates Y, so as to superimpose the first weft tracer yarn 102a of the blank 200 with the part of the visual mark 502a of the first weft tracer yarn located between the warp tracer yarn 101a and the edge 205a of the fiber blank 200 intended to form the leading edge.

[0070] The fiber blank 200 is then deformed from the warp tracer yarn 101a towards the edge 205b of the fiber blank 200 intended to form the trailing edge of the blade, that is to say in the direction of decreasing ordinates Y, so as to superimpose the first weft tracer yarn 102a of the blank 200 with the part of the visual reference 502a of the first weft tracer yarn located between the warp tracer yarn 101a and the edge 205b of the fiber blank intended to form the trailing edge.

[0071] After deforming the fiber blank 200 on both sides of the warp tracer yarn 101a, the first weft tracer yarn 102a is well superimposed over its entire length on the visual mark 502a of the weft tracer yarn. At the end of this second step, the warp tracer yarn 101a preferably remains superimposed on its corresponding visual mark 501a.

[0072] According to a third step illustrated in [Fig.8], the laser projector 5 then indicates at least the visual reference mark 502b of the second weft tracer yarn starting from the bottom of the blade of the blank 200, that is to say the second weft tracer yarn in the direction X of the increasing abscissas. This visual reference mark 502b of the second weft tracer yarn corresponds to the reference position of the second weft tracer yarn 102b on the fiber preform shaped in the shaping mold. Thus, the fiber blank 200 must be deformed so as to make the second weft tracer yarn 102b present on its face coincide with the visual reference mark 502b of the second weft tracer yarn. Preferably, the laser projector 5 also indicates the visual reference mark 501a of the warp tracer yarn and the reference mark 502a of the second weft tracer yarn.

[0073] The fiber blank 200 is deformed from the warp tracer yarn 101a towards the edge 205a of the fiber blank 200 intended to form the leading edge of the blade, that is to say in the direction of increasing Y ordinates, so as to superimpose the second weft tracer yarn 102b of the blank 200 with the part of the visual reference 502b of the second weft tracer yarn located between the warp tracer yarn 101a and the edge 205a of the fiber blank 200 intended to form the leading edge.

[0074] The fiber blank 200 is then deformed from the warp tracer yarn 101a towards the edge 205b of the fiber blank 200 intended to form the trailing edge of the blade, that is to say in the direction of decreasing Y ordinates, so as to superimpose the second weft tracer yarn 102b of the blank 200 with the part of the visual reference 502b of the second weft tracer yarn located between the warp tracer yarn 101a and the edge 205b of the fiber blank intended to form the trailing edge.

[0075] After having deformed the fiber blank 200 on both sides of the warp tracer yarn 101a, the second weft tracer yarn 102b is well superimposed over its entire length on the corresponding visual mark 502b of the weft tracer thread. At the end of this third step, the warp tracer thread 101a preferably remains superimposed on its corresponding visual mark 501a, and the first weft tracer thread 102a preferably remains superimposed on its visual mark 502a.

[0076] According to a fourth step illustrated in [Fig.9], the laser projector 5 then indicates at least the visual reference mark 502c of the third weft tracer wire starting from the bottom of the blade of the blank 200, that is to say of the second weft tracer wire in the direction X of the increasing abscissas. This visual reference mark 502c of the third weft tracer wire corresponds to the reference position of the third weft tracer wire 102c on the fiber preform shaped in the shaping mold. Thus, the fiber blank 200 must be deformed so as to make the third weft tracer wire 102c present on its face coincide with the visual reference mark 502c of the third weft tracer wire. Preferably, the laser projector 5 also indicates the visual mark 501a of the warp tracer thread, the mark 502a of the second weft tracer thread and the mark 502b of the third weft tracer thread.

[0077] The fiber blank 200 is deformed from the warp tracer yarn 101a towards the edge 205a of the fiber blank 200 intended to form the leading edge of the blade, that is to say in the direction of increasing Y ordinates, so as to superimpose the third weft tracer yarn 102c of the blank 200 with the part of the visual reference 502c of the third weft tracer yarn located between the warp tracer yarn 101a and the edge 205a of the fiber blank 200 intended to form the leading edge.

[0078] The fiber blank 200 is then deformed from the warp tracer yarn 101a towards the edge 205b of the fiber blank 200 intended to form the trailing edge of the blade, that is to say in the direction of decreasing Y ordinates, so as to superimpose the third weft tracer yarn 102c of the blank 200 with the part of the visual reference 502c of the third weft tracer yarn located between the warp tracer yarn 101a and the edge 205b of the fiber blank intended to form the trailing edge.

[0079] After deforming the fiber blank 200 on both sides of the warp tracer yarn 101a, the third weft tracer yarn 102c is well superimposed over its entire length on the corresponding visual mark 502c of the weft tracer yarn. At the end of this third step, the warp tracer yarn 101a preferably remains superimposed on its corresponding visual mark 501a, the first weft tracer yarn 102a preferably remains superimposed on its visual mark 502a and the second weft tracer yarn 102b preferably remains superimposed on its visual mark 502b.

[0080] In the example illustrated in Figures 4 to 9, there is only one warp tracer thread and three weft tracer threads. It is of course not outside the scope of the invention if the number of weft tracer threads is less than or greater than three.

[0081] For each additional weft tracer thread located above the weft tracer thread previous weft in the direction of increasing abscissas, the procedure is the same as in the fourth step. The laser projector must display the visual mark corresponding to the additional weft tracer yarn, preferably displaying the visual mark corresponding to the warp tracer yarn and the previous weft tracer yarns. The fiber blank 200 is then deformed from the warp tracer yarn 101a towards the edge 205a of the fiber blank 200 intended to form the leading edge of the blade, then the fiber blank 200 is deformed from the warp tracer yarn 101a towards the edge 205b of the fiber blank 200 intended to form the trailing edge of the blade, so as to superimpose over its entire length the additional weft yarn with the corresponding visual mark.At the end of this additional step, the warp tracer thread preferably remains superimposed on its corresponding visual mark and the previous weft tracer threads preferably remain superimposed on their corresponding visual mark.

[0082] By deforming the fiber blank 200 from the warp tracer yarn 101a, preferably positioned towards the center of the fiber blank 200, towards the edges of the blank, good repeatability of the deformation and good control of the location of the offset zones are ensured, which will be mainly located on the edges of the blank.

[0083] By deforming the fiber blank 200 to make the weft tracer yarns correspond to their visual reference from the bottom of the blank blade to the top of the blank blade, the offset is limited to the root and bottom of the blade. Indeed, as the fiber blank 200 is deformed away from the blocked part, that is to say the root of the blank, the offset becomes more and more significant. Since the material properties are usually less good at the root and at its junction with the blade, it is preferable to limit the offset to these locations, to transfer it to the top of the blade where the material characteristics are better and will allow better tolerance to the offset. Further, this deformation from the bottom of the blade of the blank 200 to the top of the blade of the blank 200 facilitates repeatability of the deformation with a controlled arrangement of the de-framing zones.

[0084] It is of course not outside the scope of the invention if the roles of the edge of the blank intended to form the leading edge of the blade and the edge of the blank intended to form the trailing edge are exchanged or alternated during the preceding steps. The deformation of the fiber blank from the warp tracer yarn to a first edge of the blank, then from the warp tracer yarn to a second edge of the blank for each weft tracer yarn simplifies the deformation of the fiber blank in the direction of the Y ordinates. A single operator can easily and quickly repeat this sequence of deformations while maintaining good repeatability and a location of the offset zones identical from one blade to another. This sequence of deformations constitutes a preferred embodiment of the invention.

[0085] However, it is not outside the scope of the invention if the deformation of the fiber blank in the direction of the Y ordinates is carried out simultaneously or alternately on either side of the warp tracer yarn towards each of the edges to superimpose a weft tracer yarn on its corresponding visual reference. However, this sequence of deformations is relatively more difficult to implement for a single operator, while maintaining good repeatability.

[0086] When the fiber blank is fully deformed, all the visual markers of the tracer wires can be displayed again - with or without the tolerances - so as to check that all the tracer wires are correctly superimposed on the corresponding visual marker. Minor deformations can be made to ensure satisfactory superposition of all the tracer wires with their visual marker.

[0087] If the fiber blank has been moistened before the deformation steps, it can be dried after being deformed.

[0088] After these deformation steps, a step of compacting the deformed fiber blank in a compacting mold can be carried out, possibly preceded by a pre-compaction step. These pre-compaction or compacting steps are for example described in document US2016243777A1 or US2016288380A1. The compacting mold can comprise the shaping mold.

[0089] Thus, a fibrous preform is obtained after shaping and possibly compacting the fibrous blank.

[0090] The fiber preform is then impregnated with a thermosetting resin that is polymerized by heat treatment. For example, the well-known injection or transfer molding process known as RTM ("Resin Transfer Molding") is used for this purpose. According to the RTM process, a resin, for example a thermosetting resin, is injected via an injection port into the internal space occupied by the preform in the injection mold. This configuration allows the establishment of a pressure gradient between the lower part of the preform where the resin is injected and the upper part of the preform located near the discharge port. In this way, the resin injected substantially at the level of the lower part of the preform will gradually impregnate the entire preform by circulating in it up to the discharge port through which the surplus is discharged.Of course, injection molding tooling may include multiple injection ports and multiple exhaust ports.

[0091] Resins suitable for RTM processes are well known. They preferably have a low viscosity to facilitate their injection into the fibers. The choice of temperature class and / or the chemical nature of the resin is determined according to the thermomechanical stresses to which the part must be subjected. Once the resin has been injected throughout the reinforcement, it is polymerized by treatment thermal in accordance with the RTM process.

[0092] After injection and polymerization, the blade is demolded. It may optionally undergo a post-curing cycle to improve its thermomechanical characteristics. Finally, the blade is trimmed to remove excess resin and chamfers may be machined. This produces a composite part formed from a fibrous reinforcement densified by a matrix.

[0093] Protective layers can be glued onto the composite part thus obtained.

Claims

Claims

1. Method for shaping a fiber blank (200) extending longitudinally in an X direction and transversely in a Y direction, obtained by three-dimensional weaving between a plurality of warp threads (101) and a plurality of weft threads (102) and intended to form a fiber preform for a turbomachine blade, the fiber blank (200) comprising a root blank (203) intended to form the blade root and a blade blank (205) intended to form the blade blade, the fiber blank (200) comprising a reference face (205c) extending in the Y direction between a first edge (205a) and a second edge (205b) intended to form the leading edge and the trailing edge of the blade, the fiber blank (200) further comprising a warp tracer thread (101a) extending on the reference face (205c) in the X direction from the foot blank (203) and at least one weft tracer thread (102a, 102b,102c) extending on the reference face (205c) in the Y direction between the first edge (205a) and the second edge (205b), the method comprising at least:, - placing the fiber blank (200) in a shaping mold (6) so that the reference face (205c) is visible, - holding the foot blank (203) in the shaping mold (6), - the projection of at least one visual warp marker (501a) onto the reference face (205c) of the fiber blank (200) corresponding to a reference location of the warp tracer yarn (101a), - deforming the blade blank (205) from the bottom of the blade blank to the top of the blade blank in the X direction so as to match the warp tracer yarn (101a) with the warp visual marker (501a), - projecting at least one weft visual marker (502a, 502b, 502c) onto the reference face (205c) of the fiber blank (200) corresponding to a reference location of the weft tracer yarn (102a, 102b, 102c), - deforming the blade blank (205) in the Y direction from the warp tracer yarn (101a) to the first edge (205a) and to the second edge (205b) of the blank (200) so as to match the weft tracer yarn (102a, 102b, 102c) with the weft visual mark (502a, 502b, 502c).

2. A shaping method according to claim 1, wherein the fiber blank (200) comprises a plurality of weft tracer yarns (102a, 102b, 102c) distributed between the bottom of the blade blank (205) and the top of the blade blank (205) and wherein a plurality of weft visual marks (502a, 502b, 502c) corresponding to a reference location of the weft tracer yarns (102a, 102b, 102c) are projected, the following step being repeated for each weft tracer yarn in order from the bottom of the blade blank to the top of the blade blank: - deforming the blade blank (205) in the Y direction from the warp tracer yarn (101a) to the first edge (205a) and up to the second edge (205b) of the blank (200) so as to match the weft tracer yarn (102a, 102b, 102c) with the corresponding weft visual mark (502a, 502b, 502c), so as to match all the weft tracer yarns (102a, 102b,102c) with the corresponding frame visual cue (502a, 502b, 502c).,

3. A shaping method according to claim 1 or 2, wherein the deformation of the blade blank (205) in the Y direction is carried out from the warp tracer yarn (101a) to the first edge (205a) of the blank (200) so as to match the weft tracer yarn (102a, 102b, 102c) with a part of the weft visual mark (502a, 502b, 502c), and then from the warp tracer yarn (101a) to the second edge (205b) of the blank (200) so as to match the weft tracer yarn (102a, 102b, 102c) with the corresponding weft visual mark (502a, 502b, 502c).

4. A shaping method according to any one of claims 1 to 3, wherein the projection of the visual markers (501a, 502a, 502b, 502c) is carried out by laser.

5. A shaping method according to any one of claims 1 to 4, wherein the visual marker (501a, 502a, 502b, 502c) corresponding to a tracer wire (101a, 102a, 102b, 102c) comprises a line of the same width as said tracer wire.

6. A shaping method according to any one of claims 1 to 5, wherein the visual marker (501a, 502a, 502b, 502c) corresponding to a tracer wire (101a, 102a, 102b, 102c) comprises two lines delimiting an area corresponding to the reference location of said tracer wire.

7. A shaping method according to any one of claims 1 to 6, wherein the fibrous blank (200) is moistened before being

8. deformed to facilitate its deformation. Method for manufacturing a turbomachine blade from composite material, comprising: - producing a fiber blank (200) by three-dimensional weaving of yarns comprising a root blank (203) intended to form the blade root and a blade blank (205) intended to form the blade, the fiber blank (200) comprising a reference face (205c) extending between a first edge (205a) and a second edge (205b) intended to form the leading edge and the trailing edge of the blade, the yarns comprising a warp tracer yarn (101a) and at least one weft tracer yarn (102a, 102b, 102c) arranged at least on the reference surface (205c), - cutting the fiber blank (200) while leaving intact the tracer wires (101a, 102a, 102b, 102c) located on the reference surface (205c) to obtain a trimmed fiber blank capable of taking the shape and dimensions of the constituent parts of the blade, - shaping the fiber blank (200) according to the shaping method according to any one of claims 1 to 7 to obtain a formed fiber preform, - injecting into the fiber preform (200) a matrix precursor resin in order to impregnate the fiber preform, - the transformation of the matrix precursor resin in the fiber preform into a matrix so as to obtain a part made of composite material comprising a fiber reinforcement densified by a matrix and having the shape and dimensions of the blade.

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