Method for manufacturing a part from composite material with a positioning datum and the resulting part
The method of creating blind holes in composite material parts through internal housings simplifies manufacturing by eliminating additional machining, reducing complexity and cost while ensuring precise positioning for finishing treatments.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- SAFRAN CERAMICS SA
- Filing Date
- 2024-11-19
- Publication Date
- 2026-05-22
AI Technical Summary
The existing manufacturing process for composite material parts is complex and costly due to the need for additional machining operations to remove sacrificial over-lengths and create reference points for finishing treatments.
A method involving the production of a fibrous preform with an internal housing for an insertion element, followed by densification and removal of a portion to create blind holes for holding and positioning, eliminating the need for additional machining.
This method simplifies the manufacturing process by integrating blind holes for tool holding without extra operations, reducing costs and enhancing the efficiency of composite material part production.
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Abstract
Description
Title of the invention: Method for manufacturing a part made of composite material with a positioning reference frame and the resulting part. Technical field
[0001] The present invention relates to the manufacture of parts made of composite material. Previous technique
[0002] One application of the invention is the production of parts made of structural composite material, that is, structural parts with fiber reinforcement and densified by a matrix. Composite materials make it possible to produce parts with a lower overall mass than the same parts when made of metallic material. In the field of aircraft engines, composite materials contribute to optimizing the performance of turbomachinery, particularly by reducing the overall mass of the turbomachine, which contributes to lower fuel consumption and therefore to a significant reduction in pollutant emissions. Furthermore, when made of thermostructural composite material, the parts allow for higher operating temperatures, which improves engine efficiency and further reduces fuel consumption.
[0003] The manufacture of a part in composite material typically includes the production of a fibrous preform and the densification of this preform by a matrix so as to obtain a part in composite material comprising a fibrous reinforcement densified by the matrix.
[0004] After densification, the part is generally subjected to one or more finishing treatments, such as the application of a surface coating. For this purpose, the part is manufactured with one or more extra lengths which are used to support the part during the finishing treatment(s). The extra lengths allow the part to be referenced in tooling for carrying out the treatments and also provide stable pre-tensioning outside of the service areas.
[0005] A machining operation is then carried out to remove the sacrificial over-length(s) in order to obtain the final geometry of the part.
[0006] However, this solution increases the number of steps and, consequently, the cost of manufacturing a part in composite material.
[0007] It is therefore desirable to have a simplified and more economical solution for maintaining and referencing a part made of composite material. Description of the invention
[0008] To this end, according to the invention, a method for manufacturing a part made of composite material is proposed, comprising at least:
[0009] - the production of a fibrous preform comprising at least first and two adjacent parts in a longitudinal direction, the first part having, in a direction perpendicular to the longitudinal direction, a thickness greater than the thickness of the second part, the first part comprising a debonding delimiting an internal housing between a first and a second skin,
[0010] - the densification of the fibrous preform by a matrix so as to obtain a a composite material part comprising a fibrous reinforcement densified by the matrix, said part comprising first and second parts adjacent in the longitudinal direction, the first part having, in a direction perpendicular to the longitudinal direction, a thickness greater than the thickness of the second part,
[0011] characterized in that the process further comprises, before the densification step of the fibrous preform:
[0012] - the production of an insertion element comprising at least one internal cavity,
[0013] - the arrangement of the insertion element in the internal housing between the first and second skin,
[0014] and in that said process further comprises after the densification step of the fibrous preform:
[0015] - the removal of a portion of the first part of the piece at the level of said at least a cavity so as to obtain at least one blind hole opening onto one end of said insertion element.
[0016] The process of the invention thus makes it possible to obtain a part made of composite material which, in its final geometry, is provided with one or more blind holes suitable for cooperating with holding and positioning means, such as pins or lugs, of a processing tool. The process of the invention is remarkable in that the blind hole(s) are formed without adding any additional operations, such as drilling, compared to the machining usually performed on the part at the end of its manufacture.
[0017] According to a particular feature of the process of the invention, the insertion element is produced by additive manufacturing.
[0018] According to another particular feature of the process of the invention, the fibrous preform comprises carbon fibers or ceramic fibers. In this case, the process may further comprise the following steps:
[0019] - consolidation of the fibrous preform by chemical infiltration in the gas phase,
[0020] - injection under pressure of a liquid containing a powder of ceramic particles refractory or particles of a refractory ceramic precursor in the fibrous preform,
[0021] - drainage of the liquid that has passed through the fibrous preform and retention of the powder of refractory ceramic particles or particles of a refractory ceramic precursor inside said preform so as to obtain a fibrous preform loaded with refractory ceramic particles or particles of a refractory ceramic precursor, the liquid being evacuated by at least one vent present on the bottom of the mold,
[0022] - drying of the fibrous preform, and
[0023] - infiltration of the fibrous preform with a molten silicon-based composition so as to form a refractory ceramic matrix in said preform.
[0024] According to another particular feature of the process of the invention, the insertion element is made of a ceramic material chosen from one of the following materials: silicon carbide, silicon carbide / silicon and silicon nitride.
[0025] According to another particular feature of the method of the invention, it comprises, after removing the portion of the first part, placing the composite material part on a processing tool, said tooling, at least one blind hole cooperating with a retaining and positioning pin for the processing tooling, and applying at least one treatment to said composite material part. Thanks to the method of the invention, the part can be processed into its final geometry, the treatment(s) applied to the part corresponding to the final manufacturing steps.
[0026] The invention also relates to a composite material part comprising a fibrous reinforcement densified by a matrix, the part comprising at least first and second parts adjacent in a longitudinal direction, the first part having, in a direction perpendicular to the longitudinal direction, a thickness greater than the thickness of the second part, the fibrous reinforcement comprising in the first part a debonding delimiting an internal housing between a first and a second skin, characterized in that it further comprises an insertion element present in the internal housing between the first and second skins,the insertion element extending along the longitudinal direction between a first end present at a junction between the first and second parts and a second end opening outside the internal housing, and in that the insertion element comprises at least one blind hole opening onto the second end of said insertion element.
[0027] According to a particular feature of the part of the invention, the first end of the insertion element has, in a direction perpendicular to the longitudinal direction, a thickness decreasing towards the second part.
[0028] According to another particular feature of the part of the invention, the fibrous preform comprises carbon fibers or ceramic fibers. The part may in this case be made of a ceramic matrix composite material and the insert element of a ceramic material selected from one of the following materials: silicon carbide, silicon carbide / silicon and silicon nitride.
[0029] According to another particular feature of the part of the invention, it further comprises at least one surface coating.
[0030] According to another particular feature of the part of the invention, it corresponds to a gas turbine blade, the first part corresponding to a blade foot and the second part corresponding to an aerodynamic profile. Brief description of the drawings
[0031] [Fig-1] Fig. 1 illustrates in a very schematic way a woven fibrous blank three-dimensional for producing a fibrous preform according to an embodiment of the invention,
[0032] [Fig.2] The [Fig.2] is a schematic perspective view of an insertion element intended to be inserted into the fibrous blank of the [Fig.1],
[0033] [Fig.3] The [Fig.3] is a schematic view of a fibrous preform incorporating the insert of the [Fig.2],
[0034] [Fig.4] The [Fig.4] is a schematic view of a part made of composite material obtained from the fibrous preform of the [Fig.3],
[0035] [Fig.5] The [Fig.5] is a schematic view of a part made of composite material obtained after removing a sacrificial portion of the part from the [Fig.4],
[0036] [Fig.6] The [Fig.6] is another schematic view of the composite material part of the [Fig.5],
[0037] [Fig.7] Fig.7 shows the composite material part of figures 5 and 6 positioned on a processing tool. Description of the implementation methods
[0038] The invention applies generally to the manufacture of composite material parts, the manufacturing process of which includes one or more processing steps carried out after the densification step. The parts may, in particular, be made of organic matrix composite (OMC), carbon matrix composite (C / C), and ceramic matrix composite (CMC).
[0039] The invention finds an advantageous but not exclusive application in the manufacture of blades for aeronautical gas turbine engines.
[0040] An example of implementation of the process of the invention applied to the manufacture of a CMC turbine blade is described below.
[0041] The process begins with the production of a fibrous blank obtained here by three-dimensional weaving or by multi-layer weaving.
[0042] By "three-dimensional weaving" or "3D weaving" we mean here a weaving method in which at least some of the warp yarns bind weft yarns over several weft layers.
[0043] By "multilayer weave" is meant here a 3D weave with several layers of weft, the basic weave of each layer being equivalent to a classic 2D fabric weave, such as a plain weave, satin or twill weave, but with certain points of the weave which link the weft layers together.
[0044] The production of the fibrous blank by 3D or multilayer weaving makes it possible to obtain a bond between the layers, thus ensuring good mechanical strength of the fibrous blank and the resulting composite material part, in a single textile operation. The 3D weave can notably be an "interlock" weave. "Interlock weave" here refers to a 3D weave structure in which each warp layer connects several weft layers, with all the yarns in the same warp column having the same movement within the plane of the weave.
[0045] An example of the realization of a fibrous blank according to the invention is now described. In this example, the weaving is carried out on a Jacquard-type loom.
[0046] Fig. 1 shows very schematically a fibrous blank 100 from which a fibrous preform 200 is obtained for forming the fibrous reinforcement of a turbine blade.
[0047] The blank 100 of the fibrous preform 200 is obtained by three-dimensional weaving, or 3D weaving, or by multilayer weaving carried out in a known manner using a Jacquard-type loom on which a bundle of warp yarns or strands 201 is arranged in a plurality of layers and extending in a longitudinal direction DL corresponding to the span direction of the blade to be manufactured, the warp yarns being linked by weft layers 202 also arranged in a plurality of layers and extending in a transverse direction DT perpendicular to the DL direction and corresponding to the chord direction of the blade to be manufactured. A detailed example of the realization of a fibrous preform intended to form the fibrous reinforcement of an aircraft engine blade is described in particular in detail in US documents 7,101,154, US 7,241,112 and WO 2010 / 061140.
[0048] The fibrous preform 200 comprises along the longitudinal direction DL a part of foot preform 203 and a part of aerodynamic profile preform 208.
[0049] During weaving, a debinding 206 is made inside the foot preform part 203 of the fibrous blank 100 between two successive layers of warp yarns. The debonding 206 extends along a plane parallel to the surface of the fibrous blank and over a debonding zone delimited by a contour 206a separating the foot preform portion 203 into a first and second skins 204 and 205. Furthermore, the debonding 206 extends in the transverse direction DT between a first lateral edge 2030 and a second lateral edge 2031. The debonding 206 also opens at the free lower end 2032 of the foot preform portion 203. The debonding 206 thus forms an internal recess 240 in the foot preform portion 203 which is accessible via the free lower end 2032.
[0050] The internal housing 240 is intended to receive an insertion element during the shaping of the fibrous blank. According to the invention, the insertion element comprises at least one internal cavity. Here, "internal cavity" means an empty volume within the insertion element that does not open onto its external surface.
[0051] Figure 2 illustrates an insertion element 10 which here comprises two internal cavities 12 and 13 each extending along the longitudinal direction between an upstream end 11 and a downstream end 14 and set back from them.
[0052] The insert element is preferably manufactured by additive manufacturing. Among the additive manufacturing processes that can be used, 3D printing with fused filament and powder bed fusion or sintering processes (also known as Power Bed Fusion or Sintering) may be mentioned. Powder bed fusion or sintering processes include, in particular, Selective Laser Sintering, Selective Laser Melting, Beam Laser Melting, and Electron Beam Melting.
[0053] The shape and location of the cavity or cavities of the insertion element are defined according to the shape and referencing of the means for holding the processing tooling which will be used to process the part in composite material.
[0054] In the example described here, the insert element is made of a ceramic material compatible with the ceramic material of the part in which it is integrated. The insert element may be made, in particular but not exclusively, of silicon carbide (SiC), silicon carbide / silicon (SiC / Si) and silicon nitride (Si3N4).
[0055] The material of the insertion element can be dense, i.e., with a zero or near-zero porosity, or it can exhibit both communicating and open porosity (opening onto the surface of the structure) in the three spatial directions X, Y, Z, as with a lattice or gyroid structure. In the latter case, the internal cavity or cavities are made with a sealed wall so as not to be filled during the densification of the fibrous preform.
[0056] Figure 3 illustrates the fibrous preform 200 after arrangement of the insertion element 10 in the internal housing 240 so that the foot preform part 203 has, in a direction DE perpendicular to the longitudinal direction DL and transverse direction DT, a thickness E203 greater than the thickness E2o s of the aerodynamic profile preform part 208.
[0057] In the example described here, the insertion element 10 has, in a direction De perpendicular to the longitudinal direction DL and transverse direction DT, a thickness Eio decreasing towards the preform part of the aerodynamic profile 208. The element 10 thus has an upstream end 11 of tapered shape which is housed in the bottom of the internal housing 240. The insertion element 10 being rigid, it allows both shaping of the preform part of the foot 203 and control of the fiber content in these preform parts.
[0058] Once the fibrous preform 200 is produced, it is consolidated. In the example described here, the preform is consolidated by depositing an interphase onto the surface of the preform fibers using chemical gas infiltration (CVI). For this purpose, the preform, held in a shaping tool, for example made of graphite, is placed in a furnace or CVI system to deposit an interphase onto the surface of the fibers of the texture. This interphase is based, in particular, on boron nitride (BN) or pyrocarbon (PyC). The thickness of the interphase is preferably between 10 nm and 1000 nm.
[0059] The next step consists of impregnating the preform with a slurry according to the injection molding process (also known as "Slurry Cast" or "STM" for "Slurry Transfer Molding"). For this purpose, and in a known manner, the fibrous preform 200, consolidated with the insert element 10 present in the internal cavity 240, is placed in a mold of a tooling into which a liquid loaded with refractory ceramic particles or particles of a refractory ceramic precursor is injected in order to penetrate the porosity of the fibrous preform 200.
[0060] The loaded liquid may, for example, be a slip containing refractory ceramic particles designed to enable the formation of a refractory ceramic matrix within the porosity of the fibrous preform. The slip may, for example, be a suspension of SiC powder in water.
[0061] During and after the injection of the slip, the liquid is drained or filtered through a piece of porous material so that the refractory ceramic particles are deposited by sedimentation in the porosity of the fibrous preform and possibly in the accessible porosity of the insertion element 10.
[0062] Once the injection and drainage steps have been carried out, a fibrous preform 200 loaded with refractory ceramic particles, for example SiC particles, is obtained.
[0063] The preform obtained is then dried and demolded, the preform being able to retain after demolding the shape adopted in the molding cavity, for example its shape adopted after compaction between the mold and the counter-mold thanks to the presence of a binder in the slip such as PVA.
[0064] The preform is then infiltrated with a molten silicon-based composition (silicidation) so as to form a ceramic matrix, a densification process known as the MI process ("Melt Infiltration").
[0065] The steps of impregnating the preform with a slip and silicifying, implemented for densification, can be replaced by a densification process called "PIP" (for "Polymer Impregnation & Pyrolysis"). This process, known to exist, involves impregnating the preform with a pre-ceramic polymer followed by pyrolysis, with these two cycles being repeated several times.
[0066] The loaded liquid may, alternatively, contain particles of a refractory ceramic precursor, for example of the sol-gel or polymeric type. In this case, the heat treatment includes at least one step of transforming the refractory ceramic precursor into a ceramic material (the so-called ceramization step), possibly followed by an additional sintering step to further densify the composite part.
[0067] As illustrated in [Fig. 4], an "intermediate" part made of CMC 300 composite material is then obtained, comprising a fibrous reinforcement 310 formed by the fibrous preform 200 and the insertion element 10. More precisely, the resulting part made of CMC 300 composite material comprises first and second parts 303 and 308 adjacent in the longitudinal direction DL, the first part 303 having, in a direction DE perpendicular to the longitudinal direction DL and the transverse direction Dt, a thickness E303 greater than the thickness E308 of the second part 308. The first part 303 includes the debonding 206 ([Fig. 1]) delimiting, between two composite skins 304 and 305, the internal housing 340 of the part in which the insertion element 10 is located with the internal cavities 12 and 13.
[0068] The manufacturing process of the invention further comprises a step of removing a sacrificial portion 3030 from the first part 303 comprising a first portion 10a of the insertion element 10 so as to leave on the part 300 a remaining portion 3031 comprising a second portion 10b of the insertion element. According to the invention, the removal of the sacrificial portion 3030 is carried out along a removal line Dc which passes through the internal cavities 12 and 13 of the element Insertion 10. The sacrificial portion 3030 can be removed by cutting along the withdrawal line Dc, for example by water jet, or by machining up to the withdrawal line Dc.
[0069] Once the sacrificial portion 3030 is eliminated, we obtain, as illustrated in figures 5 and 6, a part made of composite material 400 which includes a first part 403 corresponding to the remaining portion 3031 of the first part 303, the first part 403 comprising between two composite skins 404 and 405 an insertion element 20 corresponding to the second portion 10b of the insertion element. The composite material part 400 also includes a second part 408 adjacent to the first part 403, corresponding to the second part 308 of part 300. The first part 403 has, in a direction DE perpendicular to the longitudinal direction DL and the transverse direction DT, a thickness E403 greater than the thickness E408 of the second part 408. The fibrous reinforcement of part 400 includes in the first part 403 a debonding corresponding to the debonding 206, delimiting an internal recess 440 between the two composite skins 404 and 405.The insertion element 20 extends along the longitudinal direction DL between a first end 21 present at a junction between the first and second parts 403 and 408 and a second end 22 opening outside the internal housing 440.
[0070] In the example described here, the composite material part 400 corresponds to a gas turbine blade. Thus, the first part 403 corresponds to a blade root while the second part 408 corresponds to an aerodynamic profile.
[0071] Since the sacrificial portion 3030 is delimited by a withdrawal line which passes through the internal cavities 12 and 13, the latter open at the exposed end 24 of the insertion element 20 thus forming respectively two blind holes 22 and 23 corresponding to the remaining portions respectively of the internal cavities 12 and 13 of the insertion element 10.
[0072] As illustrated in [Fig.7], the blind holes 22 and 23 cooperate with retaining pins or lugs 32 and 33 present on a support 31 of a tooling of a processing apparatus 30. The composite material part 400 can thus be precisely positioned on a tooling and receive one or more treatments such as the deposition or formation of a surface coating on the part 400 in order to improve its surface condition and / or to form a protective layer on the surface of the part.
Claims
Demands
1. A method for manufacturing a part made of composite material (400) comprising at least: - the creation of a fibrous preform (200) comprising at least first and second parts (203, 208) adjacent in a longitudinal direction (DL), the first part (203) having, in a direction perpendicular to the longitudinal direction, a thickness (E203) greater than the thickness (E2os) of the second part (208), the first part comprising a debonding (206) delimiting an internal housing (240) between a first and a second skin (204, 205), - the densification of the fibrous preform by a matrix so as to obtain a part made of composite material (300) comprising a fibrous reinforcement densified by the matrix, said part comprising first and second parts (303, 308) adjacent in the longitudinal direction, the first part (303) having, in a direction perpendicular to the longitudinal direction,a thickness (E3 03) greater than the thickness (E3 os) of the second part (308), characterized in that the process further comprises, before the densification step of the fibrous preform: - the creation of an insertion element (10) having at least one internal cavity (12, 13), - the placement of the insertion element (10) in the internal housing (240) between the first and second skins (204, 205), and in that said process further comprises, after the densification step of the fibrous preform: - the removal of a portion (3030) of the first part (303) of the piece at the level of said at least one cavity so as to obtain at least one blind hole (22, 23) opening onto an end (24) of said insertion element.
2. A method according to claim 1, wherein the insertion element (10) is produced by additive manufacturing.
3. A method according to claim 1 or 2, wherein the fibrous preform (200) comprises carbon fibers or ceramic material fibers.
4. A method according to claim 3 further comprising the following steps: - consolidation of the fibrous preform by chemical infiltration in the gas phase, - injection under pressure of a liquid containing a powder of refractory ceramic particles or particles of a refractory ceramic precursor into the fibrous preform (200), - drainage of the liquid having passed through the fibrous preform (200) and retention of the powder of refractory ceramic particles or particles of a refractory ceramic precursor inside said preform so as to obtain a fibrous preform loaded with refractory ceramic particles or particles of a refractory ceramic precursor, the liquid being evacuated by at least one vent present on the bottom of the mold, - drying of the fibrous preform, and - infiltration of the fibrous preform with a composition based on molten silicon so as to form a refractory ceramic matrix in said preform.
5. A method according to any one of claims 1 to 4, wherein the insertion element (10) is made of a ceramic material selected from one of the following materials: silicon carbide, silicon carbide / silicon and silicon nitride.
6. A method according to any one of claims 1 to 5, comprising afterwards, removing the portion (3030) of the first part (303), placing the composite material part (400) on a processing tool (30), said at least one blind hole (22, 23) cooperating with a retaining and positioning pin (32) of the processing tool and applying at least one treatment to said composite material part.
7. A composite material part (400) comprising a matrix-densified fibrous reinforcement, the part comprising at least two adjacent first and second parts (403, 408) in a longitudinal direction (DL), the first part (403) having, in a direction perpendicular to the longitudinal direction, a thickness (E403) greater than the thickness (E400) of the second part (408), the fibrous reinforcement comprising in the first part (403) a debonding delimiting an internal housing (440) between a first and a second skin (404, 405), characterized in that it further comprises an insertion element (20) present in the internal housing (440) between the first and second skins (404, 405), the insertion element extending along the longitudinal direction (DL) between a first end (21) present at a junction between the first and second parts (403, 408) and a second end (24) opening outside the internal housing (440) and in that the insertion element (20) has at least one blind hole (22, 23) opening onto the second end (24) of said insertion element.
8. Part according to claim 7, wherein the first end (21) of the insertion element (20) has, in a direction perpendicular to the longitudinal direction (DL), a thickness decreasing towards the second part (208).
9. Part according to claim 7 or 8, wherein the fibrous preform (200) comprises carbon wires or wires of ceramic material.
10. Part according to claim 9, said part being made of ceramic matrix composite material.
11. Part according to claim 10, wherein the insertion element (20) is made of a ceramic material selected from one of the following materials: silicon carbide, silicon carbide / silicon and silicon nitride.
12. Part according to any one of claims 7 to 11, said part further comprising at least one surface coating.
13. Part according to any one of claims 7 to 12, said part corresponding to a gas turbine blade, the first part (403) corresponding to a blade root and the second part (408) corresponding to an aerodynamic profile.