Additive manufacturing method of continuous fiber reinforced composite material

Abstract

The invention relates to an additive manufacturing method of a continuous fiber reinforced composite material, belongs to the technical field of additive manufacturing, and solves the problems that an existing additive manufacturing technology is not suitable for continuous fiber reinforced metal matrix and ceramic matrix composite materials, and the process quality of additive manufacturing of a continuous fiber reinforced resin matrix composite material is poor. An additive manufacturing method of a continuous fiber reinforced composite material comprises the steps that S1, a three-dimensional model of a laminated composite material product is established, slicing treatment is carried out, and each layer of two-dimensional fiber fabric is contained in a corresponding slice; s2, prefabricating a two-dimensional fiber fabric in a layered manner; and S3, additive manufacturing of the laminated composite material product is conducted through a 3D printing forming method. According to the method, rapid additive manufacturing of continuous fiber reinforced ceramic-based, metal-based and resin-based composite materials is achieved, fiber and matrix infiltration in the obtained product is good, the interface bonding strength is high, and compared with a continuous fiber reinforced composite material obtained through an existing method, the continuous fiber reinforced composite material has better process quality and performance.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to an additive manufacturing method for continuous fiber reinforced composite materials. Background Art

[0002] Continuous fiber reinforced composite materials have received extensive attention and rapid development in the fields of aerospace, advanced weapons, automobiles, etc. due to their high specific strength, specific stiffness, good high temperature resistance, wear resistance, fatigue resistance, fracture resistance and other excellent properties. According to the different matrix materials, continuous fiber reinforced composite materials can be mainly divided into three categories: continuous fiber reinforced resin-based composite materials, continuous fiber reinforced ceramic-based composite materials, and continuous fiber reinforced metal-based composite materials.

[0003] The traditional forming processes of continuous fiber reinforced composite materials mainly include autoclave forming technology, resin transfer molding forming technology and winding forming technology. The above traditional forming processes are complicated, with many manual and semi-automatic processes, long mold development cycle and high manufacturing cost. The forming process of continuous fiber reinforced ceramic matrix and metal matrix composite materials is even more complicated and costly, which limits the application of these two composite materials.

[0004] In recent years, with the rapid development of additive manufacturing technology (i.e., 3D printing technology), the method of using additive manufacturing technology to prepare continuous fiber reinforced composite materials has begun to attract attention. At present, the additive manufacturing method of continuous fiber reinforced composite materials is mainly "prepreg fiber extrusion + fused deposition molding of thermoplastic resin", but this method is only effective for resin-based composite materials. The 3D printing of continuous fiber reinforced ceramic-based composite materials and continuous fiber reinforced metal-based composite materials is still under exploration, and there is no good mature method. At present, the manufacturing method of continuous fiber reinforced ceramic-based composite materials is mainly vapor deposition, and the manufacturing method of continuous fiber reinforced metal-based composite materials is mainly liquid die casting, but these two technical routes are relatively complex, with long manufacturing cycles and molds. Once the design needs to be changed, complex mold remaking is required. In addition, although "prepreg fiber extrusion + fused deposition molding of thermoplastic resin" can prepare continuous fiber reinforced resin-based composite materials, the resin curing quality is relatively poor, and the porosity is generally more than 20%, resulting in a loose internal structure of the product and relatively low mechanical properties; porosity is one of the important performance indicators of resin-based composite materials, and the porosity of well-cured resin-based composite materials should be below 5%. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide an additive manufacturing method for continuous fiber reinforced composite materials to solve at least one of the following technical problems: the existing additive manufacturing technology is not suitable for continuous fiber reinforced metal-based and ceramic-based composite materials, and the process quality of additive manufacturing of continuous fiber reinforced resin-based composite materials is poor (porosity is too high).

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] The present invention provides an additive manufacturing method for a continuous fiber reinforced composite material, comprising the following steps:

[0008] Step S1, establishing a three-dimensional model of a laminated composite material product, and performing slicing processing, wherein each layer of two-dimensional fiber fabric is included in a corresponding slice; the laminated composite material includes a matrix and a two-dimensional fiber fabric;

[0009] Step S2, prefabricating two-dimensional fiber fabrics in layers: first prepare two-dimensional fiber fabrics, preform the two-dimensional fiber fabrics into two-dimensional fiber preforms by prepreg method, process the two-dimensional fiber preforms into two-dimensional fiber preforms of required shapes, and stack them in the order of slice printing for standby;

[0010] Step S3, performing additive manufacturing of laminated composite products by 3D printing: when printing a certain layer of slices containing two-dimensional fiber fabrics, first accurately lay out the two-dimensional fiber preforms in the corresponding order, position them, and then lay out or spray the matrix material.

[0011] Furthermore, step S1 includes the following steps:

[0012] Step S11: using computer-aided design software to establish a three-dimensional model of the laminated composite material product;

[0013] Step S12: convert the three-dimensional model of the laminated composite product into an STL triangulated file, set the XY plane where the two-dimensional fiber fabric is located as the base plane of 3D printing, set the Z direction perpendicular to the XY plane as the layer-by-layer stacking direction, and slice the STL triangulated file.

[0014] Furthermore, in step S1, the slice thickness is greater than the thickness of the two-dimensional fiber fabric, satisfying N>M1, where N is the slice thickness and M1 is the maximum thickness of the two-dimensional fiber fabric.

[0015] Furthermore, in step S1, the first and last layers of the slice are matrix materials without fibers, satisfying N<S, where N is the slice thickness and S is the thickness of the matrix material on the upper and lower surfaces of the laminated composite product along the Z direction.

[0016] Further, step S2 includes the following steps:

[0017] Step S21: preparing a two-dimensional fiber fabric by weaving;

[0018] Step S22: using a pre-preg method to fully impregnate the two-dimensional fiber fabric with a setting agent and set the two-dimensional fiber fabric, thereby preforming the two-dimensional fiber preform into a two-dimensional fiber preform capable of being shaped;

[0019] Step S23: Processing the two-dimensional fiber preform into a two-dimensional fiber preform of a required shape, and stacking them in the order of slice printing for standby use.

[0020] Furthermore, in step S2, the fibers used to prepare the two-dimensional fiber fabric are ultra-small tow fibers and satisfy: M1≤M2<N; M1 is the maximum thickness of the two-dimensional fiber fabric, M2 is the maximum thickness of the two-dimensional fiber preform, and N is the slice thickness.

[0021] Furthermore, in step S3, the main steps of accurately laying the two-dimensional fiber preforms in the corresponding order include: before laying or spraying a layer of the matrix, accurately positioning the placement position of the two-dimensional fiber preforms of the corresponding layer by infrared scanning.

[0022] Furthermore, in step S3, the main steps of positioning include: selecting W positioning points on the two-dimensional fiber preform, and scanning the positioning points with laser or ultraviolet light to perform melting, thermal curing or photocuring positioning.

[0023] Furthermore, in step S2, when the matrix material is a thermosetting resin, the two-dimensional fiber fabric is preformed into a two-dimensional fiber preform by using a glue groove rolling prepreg method.

[0024] Furthermore, in step S2, when the matrix material is a thermoplastic resin, a thin film hot pressing prepreg method is used to preform the two-dimensional fiber fabric into a two-dimensional fiber preform.

[0025] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0026] 1. The present invention provides an additive manufacturing method for continuous fiber reinforced composite materials. The method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology is used to realize the additive manufacturing of continuous fiber reinforced laminated composite materials. The design freedom of the continuous fiber reinforced composite materials is well expanded, and the advantages of additive manufacturing can be fully utilized. Highly complex and diversified products can be quickly designed and produced without molds.

[0027] 2. The additive manufacturing method of continuous fiber reinforced composite materials provided by the present invention adopts a method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology, and a product with excellent process quality and performance can be quickly obtained by using simple process steps; among them, since the fibers and the shaping agent (preferably the same or similar to the matrix material) in the "layered prefabricated two-dimensional fiber fabric" have been fully infiltrated, bonded and shaped, and no long-term high-temperature treatment is required during the entire process, the two-dimensional fiber fabric in the final product has better uniformity, stability, integrity and consistency, and the fibers and the matrix are well infiltrated and the interface bonding strength is high.

[0028] 3. The additive manufacturing method of continuous fiber reinforced composite materials provided by the present invention adopts a method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology, so that rapid additive manufacturing of continuous fiber reinforced ceramic-based composite materials becomes possible. Compared with the existing vapor deposition method, the mold processing link can be omitted and the production cycle is shortened. The obtained product has very good process quality and performance, and can meet the mechanical properties and functional requirements of high-performance ceramic-based composite materials. For example, Example 1 of the present invention provides an additive manufacturing method for continuous silicon carbide fiber reinforced silicon carbide (SiC / SiC composite material) turbine blades The method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology (selective light curing + sintering molding) can save the mold processing link in blade manufacturing, maximize the flexibility of structural design, and achieve the optimal design of the structure from the perspective of lightweight, making rapid additive manufacturing of continuous silicon carbide fiber reinforced silicon carbide turbine blades possible; at the same time, products with excellent process quality and performance can be obtained (the density of silicon carbide ceramics of turbine blades can exceed 95%, the bending strength can reach more than 600Mpa, and it can withstand ambient temperatures above 1700℃), which can fully meet the use requirements of high-performance engines.

[0029] 4. The additive manufacturing method of continuous fiber reinforced composite materials provided by the present invention adopts a method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology, making it possible to rapidly additively manufacture continuous fiber reinforced metal-based composite materials. Compared with the existing liquid die-casting method, it can save the mold processing link, maximize the flexibility of structural design, and rapidly design and produce highly complex and diversified continuous fiber reinforced metal-based composite materials. Continuous fiber reinforced metal-based composite materials with better mechanical properties than pure metal materials are prepared with the most economical raw materials. For example, Example 2 of the present invention provides an additive manufacturing method for a tensile test piece of a continuous carbon fiber reinforced aluminum alloy composite material, and the tensile strength of the obtained test piece is increased by more than 20% compared with that of pure aluminum alloy.

[0030] 5. The additive manufacturing method of continuous fiber reinforced composite materials provided by the present invention adopts a method of combining layered prefabricated two-dimensional fiber fabrics with additive manufacturing technology, which effectively solves the problems of poor resin curing quality (porosity above 20%), loose internal structure and low mechanical properties of the continuous fiber reinforced resin-based composite materials obtained by the existing "prepreg fiber extrusion + thermoplastic resin molten deposition molding", and greatly improves the process quality and performance of additive manufacturing of continuous fiber reinforced resin-based composite materials; for example, Example 3 of the present invention provides an additive manufacturing method for a continuous carbon fiber reinforced epoxy resin composite tensile test piece, and Example 4 provides an additive manufacturing method for a continuous carbon fiber reinforced polyetheretherketone (PEEK) resin composite material. The porosity of the tensile test pieces obtained by the two is controlled below 5%. At the same time, compared with the use of "prepreg fiber extrusion + thermoplastic resin molten deposition molding", the mechanical properties are improved by more than 100%.

[0031] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings are only for the purpose of illustrating specific embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0033] Figure 1 A schematic diagram of a laminated composite material provided by an embodiment of the present invention;

[0034] Figure 2 An axonometric schematic diagram of a turbine blade provided in an embodiment of the present invention;

[0035] Figure 3 A Y-direction schematic diagram of a turbine blade provided in an embodiment of the present invention;

[0036] Figure 4 A schematic diagram of a turbine blade in the Z direction provided by an embodiment of the present invention;

[0037] Figure 5 A cross-sectional view of a slice of a layer of a two-dimensional fiber fabric included in a turbine blade provided by an embodiment of the present invention;

[0038] Figure 6 A schematic diagram of a two-dimensional fiber fabric sliced ​​from a certain layer of a turbine blade provided by an embodiment of the present invention;

[0039] Figure 7A schematic diagram of a tensile test piece in the Z direction provided by an embodiment of the present invention;

[0040] Figure 8 for Figure 7 AA cross-sectional diagram of ;

[0041] Fig. 9 is a cross-sectional view of a slice of a layer of a two-dimensional fiber fabric in a tensile test piece provided by an embodiment of the present invention;

[0042] Reference numerals:

[0043] 101-Z-section including fiber and matrix; 102-section of XY plane, i.e., the plane where the two-dimensional fiber fabric is located; 2-blade; 21-blade root; 22-blade body; 23-blade tip; 24-groove; 3-mounting base; 31-tenon; 701-tensile test piece; 702-reinforcement sheet; 703-carbon fiber two-dimensional fabric; A-first positioning point; B-second positioning point; C-third positioning point; D-fourth positioning point. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0045] The present invention provides an additive manufacturing method for a continuous fiber reinforced composite material, wherein the composite material is a laminated composite material, comprising a matrix and fibers; the fibers are two-dimensional fiber fabrics woven from continuous fibers and distributed in an XY plane;

[0046] Optionally, the material of the matrix is ​​one of ceramic, metal, thermosetting resin and thermoplastic resin.

[0047] The additive manufacturing method comprises the following steps:

[0048] Step S1: Establish a three-dimensional model of a laminated composite material product and perform slicing processing, wherein each layer of two-dimensional fiber fabric is included in a corresponding slice.

[0049] Step S1 specifically includes the following steps:

[0050] Step S11: using computer-aided design software to establish a three-dimensional model of the laminated composite material product;

[0051] Specifically, in the established three-dimensional model, the two-dimensional fiber fabric in the laminated composite product is distributed in the XY plane and accumulated in multiple layers. There is no fiber in the product along the Z direction perpendicular to the XY plane. The XY plane is also the base plane for future additive manufacturing. For example, refer to Figure 1, 101 is the Z-direction section including the fiber and the matrix. Because there is no Z-direction fiber, what can be seen in the Z-direction section is the fiber cross section and the matrix cross section. 102 is the section of the XY plane. Since the fibers are distributed in the XY plane, the fiber distribution of the two-dimensional fabric can be seen.

[0052] Optionally, the thickness of each layer of two-dimensional fiber fabric in the laminated composite material product is less than 0.5 mm. Preferably, the thickness of each layer of two-dimensional fiber fabric is less than 0.1 mm.

[0053] It should be noted that the surface of the laminated composite material product is a matrix material that does not contain fibers; such a setting can ensure that the surface of the laminated composite material product is completely flat, and the fiber fabric can be fully covered in the product shape to ensure that no fibers are exposed on the product surface after molding.

[0054] Preferably, the thickness of the matrix material (excluding fibers) of the laminated composite product along the Z-upward and lower surfaces is not less than 0.1 mm; more preferably, the thickness of the matrix material (excluding fibers) of the laminated composite product along the Z-upward and lower surfaces is not less than 0.5 mm.

[0055] Preferably, the outer contour of each layer of two-dimensional fiber fabric distributed in the XY plane of the laminated composite material product is 0.1 mm to 0.3 mm smaller than the outer contour of the product.

[0056] It should be noted that the number of layers of the two-dimensional fiber fabric can be selected as needed, and the number of layers is a natural number greater than or equal to 2; further, the material, thickness and fiber arrangement of each layer of the two-dimensional fiber fabric can be the same or different;

[0057] In a possible design, each layer of the two-dimensional fiber fabric has the same material, thickness, and fiber arrangement.

[0058] In one possible design, each layer of the two-dimensional fiber fabric has the same material and thickness, but the fiber arrangement is different.

[0059] It should be noted that the distribution of the two-dimensional fiber fabric in the matrix can be selected as needed. For example, two or more layers of two-dimensional fiber fabric are evenly or non-evenly stacked layer by layer in the matrix along a plane perpendicular to the Z direction.

[0060] Optionally, computer-aided design (CAD) software can be selected as needed, including but not limited to AutoCAD, Autodesk Inventor, SolidWorks, CATIA, Pro / E, UG NX, SolidEdge, Onespace, etc.

[0061] Step S12: convert the three-dimensional model of the laminated composite product into an STL triangulated file, set the XY plane where the two-dimensional fiber fabric is located as the base plane of 3D printing, set the Z direction perpendicular to the XY plane as the layer-by-layer stacking direction, and slice the STL triangulated file.

[0062] Specifically, the three-dimensional model of the laminated composite product established in step S11 is converted into the STL triangulated file required by the additive manufacturing system, the XY plane of the laminated composite product (that is, the plane where each layer of two-dimensional fiber fabric is located) is determined as the base plane of 3D printing, and the Z direction perpendicular to the XY plane is set as the layer-by-layer stacking direction. The STL triangulated file is sliced ​​to realize the conversion of the three-dimensional model into a two-dimensional thin film model.

[0063] It should be noted that when slicing, it is necessary to ensure that each layer of the two-dimensional fiber fabric is contained in the corresponding slice, that is, the substrate of each slice thickness completely wraps the two-dimensional fiber fabric of this layer, so that the surface is flat after laying each layer of substrate material to ensure smooth subsequent printing operations, for example, the scraper motion system can move smoothly to lay each layer of printing material;

[0064] In order to meet the above requirements, the slice thickness is greater than the thickness of the two-dimensional fiber fabric; optionally, the thickness of each layer of the two-dimensional fiber fabric can be the same or different, and the maximum thickness in the two-dimensional fiber fabric is set as M1, satisfying N>M1, N is the slice thickness, and M1 is the maximum thickness in the two-dimensional fiber fabric. Optionally, N is 0.025mm~0.5mm; preferably, N is 0.05mm~0.1mm; illustratively, M1=0.08mm, N=0.1mm.

[0065] It should be noted that the first and last layers of the slice are matrix materials that do not contain fibers, satisfying N<S, where N is the slice thickness, and S is the thickness of the matrix material (i.e., does not contain fibers) on the upper and lower surfaces of the laminated composite product along the Z direction; optionally, N is 0.025mm~0.5mm; preferably, N is 0.05mm~0.1mm; exemplarily, S=0.6mm, N=0.1mm.

[0066] It can be seen that the slice thickness N is selected according to the thickness of the two-dimensional fiber fabric and the thickness of the matrix material on the upper and lower surfaces of the product along the Z direction, ensuring that each layer of the two-dimensional fiber fabric is contained in the corresponding slice, and the first and last layers of the slice are matrix materials that do not contain fibers, so as to ensure the smooth progress of subsequent printing operations, and that the fiber fabric can be fully covered in the shape of the product after molding, ensuring that the surface of the laminated composite product is completely flat.

[0067] In one possible design, after converting the 3D model into an STL file, support can be generated by software at the bottom of the 3D model or at a location with a large slope, and the 3D model and support can be sliced ​​and imported into the 3D printing system control host together. The support here is mainly a temporary structure added to maintain the shape and stability of the printed object, which can be easily removed after printing.

[0068] Step S2, prefabricating two-dimensional fiber fabrics in layers: first prepare two-dimensional fiber fabrics, preform the two-dimensional fiber fabrics into two-dimensional fiber preforms by prepreg method, process the two-dimensional fiber preforms into two-dimensional fiber preforms of required shapes, and stack them in the order of slice printing for standby use.

[0069] Step S21: preparing a two-dimensional fiber fabric by weaving;

[0070] Specifically, a plurality of fiber bundles are regularly interlocked alternately by weaving to form a two-dimensional fiber fabric. The weaving method of the two-dimensional fiber fabric can be selected according to needs, including but not limited to weaving, braiding, knitting, etc.

[0071] It should be noted that the diameter of the fiber bundle used to prepare the two-dimensional fiber fabric is determined according to the slice thickness in step S1 to satisfy N>M1, where N is the slice thickness and M1 is the maximum thickness of the two-dimensional fiber fabric.

[0072] In a possible design, the slice thickness N is 0.05 mm to 0.1 mm. To satisfy N>M1, preferably, the fiber used to prepare the two-dimensional fiber fabric is an ultra-small tow fiber, and the ultra-small tow is a fiber not larger than 1K, where 1K means that a bundle of fiber contains 1000 single filaments; more preferably, the fiber used to prepare the two-dimensional fiber fabric is an ultra-small tow fiber of 0.1K to 0.8K;

[0073] For example, the slice thickness N=0.1 mm, the fiber bundle is 0.12K (each bundle has 120 fiber filaments), and the diameter of the filament is 8 μm, which can ensure that the thickness of the prepared two-dimensional fiber fabric is less than 0.1 mm.

[0074] Optionally, the fiber type for preparing the two-dimensional fiber fabric can be selected as needed, including but not limited to one or a combination of silicon carbide fiber, carbon fiber, silicon nitride fiber, boron fiber, basalt fiber, glass fiber, aramid fiber, and alumina (including mullite) fiber.

[0075] Optionally, the fiber arrangement of the two-dimensional fiber fabric can be selected according to needs (for example, the direction of force on the product, etc.), including but not limited to unidirectional fabric, plain fabric, twill fabric, etc. For example, the unidirectional fabric is a thinner two-dimensional fiber fabric in which the fibers are subjected to force in the main direction by evenly laying a large number of fiber filaments along a main direction and weaving the fiber filaments in the main direction together with fewer fiber filaments; see Figure 6 The two-dimensional fiber fabric corresponding to the slice adopts the shape of a unidirectional cloth. The fibers in the two-dimensional fiber fabric are mainly distributed along the Y direction, and a smaller amount of fibers are distributed along the X direction, which plays a role in linking and fixing the Y-direction fibers.

[0076] Step S22: The two-dimensional fiber fabric is fully impregnated with a setting agent and set by a pre-preg method, and is preformed into a two-dimensional fiber preform that can maintain the existing shape when picked up and placed.

[0077] It should be noted that the prepreg method can be selected according to the different base materials, including but not limited to spray rolling prepreg method, hot melt rolling prepreg method, glue groove rolling prepreg method, and film hot pressing prepreg method.

[0078] It should be noted that the setting agent used to impregnate the two-dimensional fiber fabric in the prepreg method should have good compatibility with the matrix material and sufficient adhesion to maintain the integrity during 3D printing; preferably, the type of the setting agent is the same or similar to the type of the matrix material, so that during the 3D printing process, after laying or spraying the matrix material, the setting agent in the two-dimensional fiber fabric preform and the matrix can be well compatible and penetrated with each other and then firmly combined together.

[0079] It should be noted that the process of shaping the two-dimensional fiber fabric in the prepreg method includes one or a combination of heating, pressurizing, and curing.

[0080] It is worth noting that for the four matrix materials (i.e., ceramic, metal, thermosetting resin, and thermoplastic resin), the two-dimensional fiber fabric is pretreated by the prepreg method, and the obtained two-dimensional fiber fabric preform has good rigidity and can maintain the existing shape of the two-dimensional fiber fabric during the pick-up and placement operations. At the same time, the two-dimensional fiber fabric body after the shaping treatment can control the porosity at a low level, and the fibers and the shaping agent (preferably the same or similar to the matrix material) are well infiltrated. There is no need to consider the infiltration problem of the fibers and the matrix during 3D printing, which can effectively reduce the porosity of the continuous fiber reinforced composite material.

[0081] It should be noted that in order to ensure the smooth progress of 3D printing, the thickness of the two-dimensional fiber preform is less than the slice thickness, satisfying M1≤M2<N, M1 is the maximum thickness of the two-dimensional fiber fabric, M2 is the maximum thickness of the two-dimensional fiber preform, and N is the slice thickness; optionally, N is 0.025mm~0.5mm; preferably, N is 0.05mm~0.1mm.

[0082] Furthermore, according to different base materials, four methods of prepreg (ie, spray rolling prepreg, hot melt rolling prepreg, glue tank rolling prepreg, and film hot pressing prepreg) are described in more detail.

[0083] As an optional embodiment, when the matrix material is ceramic, the two-dimensional fiber fabric can be preformed into a two-dimensional fiber preform by using a spraying and rolling prepreg method;

[0084] The main steps of the spray-roll prepreg method include: spraying liquid thermosetting resin on the surface of the two-dimensional fiber fabric, fully infiltrating and compacting the two-dimensional fiber fabric with the resin liquid through rolling, and shaping it through low-temperature precuring or light precuring to obtain a two-dimensional fiber preform.

[0085] It is understandable that the resin pre-sprayed on the surface of the two-dimensional fiber fabric will volatilize during the debinding and sintering process of the ceramic.

[0086] It should be noted that the thermosetting resin is a resin that is liquid at room temperature and can be cross-linked and cured (thermal curing or photocuring) under heating or light, including high-temperature curing resin or photosensitive resin.

[0087] Optionally, the type of resin can be selected as needed, including but not limited to epoxy resin, epoxy acrylate, polyurethane acrylic resin, polyester acrylic resin, amino acrylic resin, phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, unsaturated resin, polyurethane, and polyimide.

[0088] It should be noted that the above-mentioned rolling method refers to the squeezing of the two-dimensional fiber fabric fully soaked in resin liquid by a pair of rotating pressure rollers, and at the same time, the pressure rollers are heated to achieve low-temperature pre-curing, or the two-dimensional fiber fabric passing through the pressure rollers is irradiated with a certain amount of ultraviolet light or laser to achieve light pre-curing, and then the two-dimensional fiber preform with a certain shape and stiffness is obtained by shaping.

[0089] In a possible design, a high-temperature curing resin is sprayed on the surface of the two-dimensional fiber fabric, and the pressure roller can be heated in the rolling method to pre-cure the resin on the surface of the two-dimensional fiber fabric passing through the pressure roller at a low temperature, thereby achieving the shaping of the two-dimensional fiber fabric. Exemplarily, the high-temperature curing resin is selected from epoxy resin, and the curing temperature of the epoxy resin is 120°C. The pre-impregnated two-dimensional fiber fabric is pre-cured at a low temperature by passing through a pressure roller preheated to 60°C to become a two-dimensional fiber preform with a certain shape and stiffness.

[0090] In a possible design, a photosensitive resin is sprayed on the surface of the two-dimensional fiber fabric, and a certain amount of ultraviolet light or laser can be irradiated to the material passing through the pressure roller in the rolling method, and the photosensitive resin on the surface of the two-dimensional fiber fabric is photo-precured under the action of the laser or ultraviolet light, thereby achieving the shaping of the two-dimensional fiber fabric. Exemplarily, the photosensitive resin is selected as epoxy acrylate, and the pre-impregnated two-dimensional fiber fabric passes through a pair of rotating pressure rollers, and an ultraviolet solid laser is used to irradiate the material between the pressure rollers, so that the epoxy acrylate sprayed on the surface of the two-dimensional fiber fabric is photo-precured to become a two-dimensional fiber preform with a certain shape and stiffness.

[0091] As an optional implementation, when the matrix material is metal, the two-dimensional fiber fabric can be preformed into a two-dimensional fiber preform by using a hot melt rolling prepreg method.

[0092] The main steps of the hot melt rolling prepreg method include: immersing the two-dimensional fiber fabric in molten metal liquid, fully infiltrating, combining and compacting the two-dimensional fiber fabric and the metal liquid through rolling, and obtaining a two-dimensional fiber preform after cooling at room temperature.

[0093] It should be noted that the above rolling method refers to the squeezing of the two-dimensional fiber fabric fully soaked in metal liquid by a pair of rotating pressure rollers, so that the two-dimensional fiber fabric passing between the rollers is deformed into a two-dimensional fiber preform with a certain shape and stiffness under this action.

[0094] Preferably, the type of metal liquid used to impregnate the two-dimensional fiber fabric in the hot melt rolling prepreg method is the same as the metal type of the matrix, so that during the 3D printing process, the metal in the two-dimensional fiber preform and the matrix metal can be well compatible and infiltrated with each other and then firmly combined together, so that the interface bonding force between the two-dimensional fiber preform and the metal matrix is ​​stronger. Exemplarily, if the matrix is ​​selected as aluminum alloy, the metal liquid used to impregnate the two-dimensional fiber fabric in the hot melt rolling prepreg method is also selected as aluminum alloy. Due to the similar microstructure, the same type of metal is more easily combined together when heated by the laser beam during the 3D printing process, thereby improving the interface bonding strength.

[0095] As an optional implementation, when the matrix material is a thermosetting resin, the two-dimensional fiber fabric can be preformed into a two-dimensional fiber preform by using a glue groove rolling prepreg method.

[0096] The main steps of the glue tank rolling prepreg method include: immersing the two-dimensional fiber fabric in a glue tank containing thermosetting resin liquid, ensuring that the two-dimensional fiber fabric and the resin liquid are fully impregnated, combined and compacted by the rolling method, and shaping by low-temperature precuring or light precuring to obtain a two-dimensional fiber preform.

[0097] It should be noted that the thermosetting resin is a resin that is liquid at room temperature and can be cross-linked and cured (thermal curing or photocuring) under heating or light, including high-temperature curing resin or photosensitive resin.

[0098] Optionally, the type of resin can be selected as needed, including but not limited to epoxy resin, epoxy acrylate, polyurethane acrylic resin, polyester acrylic resin, amino acrylic resin, phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, unsaturated resin, polyurethane, and polyimide.

[0099] In a possible design, the two-dimensional fiber fabric is immersed in a glue tank containing a high-temperature curing resin liquid. The pressure roller can be heated in the rolling method to pre-cure the resin on the surface of the two-dimensional fiber fabric passing through the pressure roller at a low temperature, thereby achieving the shaping of the two-dimensional fiber fabric. Exemplarily, the high-temperature curing resin is selected as epoxy resin, and the curing temperature of the epoxy resin is 120°C. The pre-impregnated two-dimensional fiber fabric is pre-cured at a low temperature by passing through a pressure roller preheated to 60°C to become a two-dimensional fiber fabric preform with a certain shape and stiffness.

[0100] In one possible design, the two-dimensional fiber fabric is immersed in a glue tank filled with photosensitive resin liquid. The two-dimensional fiber fabric passing through the pressure roller can be irradiated with a certain amount of ultraviolet light or laser in the rolling method. The photosensitive resin on the surface of the two-dimensional fiber fabric is pre-cured under the action of ultraviolet light or laser, thereby achieving the shaping of the two-dimensional fiber fabric.

[0101] Preferably, the type of the resin liquid used to impregnate the two-dimensional fiber fabric in the glue groove rolling prepreg method is the same as the type of the resin of the matrix, so that the interface bonding force between the two-dimensional fiber preform and the resin matrix is ​​stronger during the 3D printing process. Exemplarily, if the matrix is ​​epoxy resin, the resin liquid used to impregnate the two-dimensional fiber fabric in the glue groove rolling prepreg method is also epoxy resin.

[0102] As an optional implementation, when the matrix material is a thermoplastic resin, a thin film hot pressing prepreg method can be used to preform the two-dimensional fiber fabric into a two-dimensional fiber preform.

[0103] The main steps of the film hot pressing prepreg method include: laying a plastic film with basically the same plane shape on the upper and lower surfaces of the two-dimensional fiber fabric, using a high-temperature pressure plate to melt the plastic and fully infiltrate and compact the fiber, and after cooling at room temperature, a two-dimensional fiber preform is obtained.

[0104] Preferably, the resin type of the plastic film used to impregnate the two-dimensional fiber fabric in the film hot pressing prepreg method is the same as the resin type of the matrix, so that during the 3D printing process, the interface bonding force between the two-dimensional fiber preform and the resin matrix is ​​stronger. Exemplarily, if the matrix is ​​polyetheretherketone (PEEK), the plastic film used to impregnate the two-dimensional fiber fabric in the film hot pressing prepreg method is also a polyetheretherketone (PEEK) film, and preferably, the thickness of the PEEK film is 0.02mm to 0.04mm.

[0105] Step S23: Processing the two-dimensional fiber preform into a two-dimensional fiber preform of a required shape, and stacking them in the order of slice printing for standby use.

[0106] Specifically, the two-dimensional fiber preform is processed into a two-dimensional fiber preform of a desired shape by a cutting process, and the number of layers and the outer contour of the two-dimensional fiber preform are determined according to the two-dimensional fiber fabric in the three-dimensional model of the laminated composite product established in step S1. For example, if four layers of two-dimensional fiber fabric are arranged at the 200th, 300th, 400th, and 500th layers in the three-dimensional model, four two-dimensional fiber preforms are cut out according to the outer contour of the corresponding slice layer, and the plane size of each two-dimensional fiber preform is slightly smaller than the plane size of the slice where the corresponding two-dimensional fiber preform is located, so as to ensure that no fiber is exposed on the surface of the product after molding.

[0107] Optionally, the cutting process can be selected as needed, including but not limited to automatic cutting, laser cutting, etc. Exemplarily, the automatic cutting method can use a CNC cutting machine to cut the two-dimensional fiber preform to obtain a two-dimensional fiber preform of a desired shape.

[0108] Step S3: Additive manufacturing of laminated composite products by 3D printing: When printing a certain layer of slices containing two-dimensional fiber fabrics, first accurately lay out the two-dimensional fiber preforms in the corresponding order, position them, and then lay out or spray the matrix material.

[0109] It should be noted that the main steps of accurately laying out the two-dimensional fiber preforms in the corresponding order include: before laying out or spraying a certain layer of the matrix, accurately locating the placement position of the two-dimensional fiber preforms of the corresponding layer of the matrix to be sprayed by infrared scanning, and laying them on the printed previous layer. Exemplarily, before laying out or spraying a certain layer of the matrix, the two-dimensional fiber preforms of the corresponding layer are automatically picked up by a robot, and the placement position of the two-dimensional fiber preforms of the corresponding layer of the matrix to be sprayed is accurately located by infrared scanning, and laid on the printed previous layer.

[0110] It should be noted that the main steps of the positioning include: after accurately placing the two-dimensional fiber preform of the corresponding layer, selecting W positioning points on the two-dimensional fiber preform, and scanning the positioning points with laser or ultraviolet light to melt or thermally cure / photocure (the resin in the positioning points is heated or illuminated to be thermally cured or photocured, or the metal at the positioning points is heated to melt and then cooled and solidified), similar to the mechanism of metal spot welding, so that the two-dimensional fiber preform is fixed on the printed previous layer to ensure that when the matrix material of the corresponding layer is placed (for example, sprayed or laid) later, the two-dimensional fiber preform will not move.

[0111] Preferably, the number of positioning points W is ≥ 3, and they are not on a straight line to better ensure effective positioning.

[0112] Optionally, the 3D printing molding method can be selected according to the base material, including but not limited to: selective photocuring + sintering molding method, laser selective melting molding method, selective photocuring molding method, powder sintering molding method, fused deposition molding method, etc.

[0113] As an optional implementation, when the matrix material is ceramic, the additive manufacturing of ceramic-based composite materials is carried out by using a selective light curing + sintering molding method; specifically, the following steps are included:

[0114] Step S301: preparing ceramic slurry;

[0115] Purchase commercially available ceramic slurries that can be used for 3D printing (including ceramic powders and photosensitive resins, etc.);

[0116] Step S302: Selected area light-curing molding;

[0117] The STL data file generated in step S1 is imported into the 3D printer system, and the ceramic slurry prepared in step S301 is placed in the material tank of the 3D printer to perform selective photocuring printing to obtain a precursor of a ceramic-based composite material product.

[0118] The printing equipment and specific process parameters of the selective photocuring molding can be selected and set from the parameters of the 3D printer and 3D printing molding technology in the prior art.

[0119] In one possible design, the 3D printer is equipped with a peristaltic feeding system and a precision scraper paving system. The peristaltic feeding system ensures the precise supply of ceramic materials, and the precision scraper paving system ensures that each layer of slurry is evenly spread, thereby ensuring that the thickness of each printed layer is uniform and controllable; the above-mentioned peristaltic feeding system and precision scraper auxiliary material system can also be applied to the following steps S312, S322 and S332.

[0120] In one possible design, step S302 includes the following steps:

[0121] Step S3021: When printing a certain layer of slices containing fibers, the robot automatically picks up the two-dimensional fiber preform of the current layer, and accurately positions and places it by infrared scanning. After placing the two-dimensional fiber preform of the current layer, ultraviolet light is used to scan W points on the two-dimensional fiber preform for light curing positioning; W ≥ 3, and not on a straight line;

[0122] Step S3022: the peristaltic feeding system controls the quantitative supply of the ceramic slurry;

[0123] Step S3023: The precision scraper motion system flattens the ceramic slurry in step S3022;

[0124] Step S3024: Scan the slice of the current layer with ultraviolet light to solidify it sequentially from point to line and from line to surface, thus completing the light curing of the current layer;

[0125] Step S3025: the molding printing platform descends one layer, and the precision scraper motion system returns to continue printing the next layer;

[0126] When printing a layer of slices containing fibers, printing is performed according to the above steps S3021 to S3025; when printing a layer of slices not containing fibers, printing is performed according to steps S3022 to S3025; until the last layer of slices is printed, a precursor of a ceramic-based composite material product is obtained.

[0127] Step S303: degreasing and sintering;

[0128] Specifically, the precursor of the ceramic-based composite material product printed in step S302 is placed in a degreasing furnace, in which the photosensitive resin, various additives in the precursor of the ceramic-based composite material product, and the resin sprayed on the two-dimensional fiber fabric in step S2 are volatilized and completely discharged;

[0129] Furthermore, the degreased precursor of the ceramic-based composite material product is placed in a high-temperature sintering furnace and sintered according to a certain sintering process to obtain the final ceramic-based composite material product.

[0130] The specific process parameters of debinding and sintering molding can be selected and set from the process parameters of debinding and sintering of ceramic materials in the prior art.

[0131] As an optional implementation, when the matrix material is metal, the additive manufacturing of the metal-based composite material is performed by laser selective melting forming method; specifically, the following steps are included:

[0132] Step S311: preparing metal powder;

[0133] Purchase commercially available metal powder that can be used for 3D printing;

[0134] It should be noted that the type of metal powder can be selected as needed, including but not limited to aluminum-based, magnesium-based, zinc-based, nickel-based, titanium-based, iron-based, copper-based, cobalt-chromium alloy, etc.

[0135] Step S312: laser selective melting forming;

[0136] Specifically, the STL data file generated in step S1 is imported into the 3D printer system, and the metal powder prepared in step S311 is placed into the material tank of the 3D printer to perform laser selective melting printing.

[0137] The printing equipment and specific process parameters of the laser selective melting molding can be selected and set from the parameters of the 3D printer and 3D printing molding technology in the prior art.

[0138] In one possible design, step S312 includes the following steps:

[0139] Step S3121: when printing a certain layer of slices containing fibers, the robot automatically picks up the two-dimensional fiber preform of the current layer, and accurately positions and places it by infrared scanning. After placing the two-dimensional fiber preform of the current layer, laser scans W points on the two-dimensional fiber preform for melting and positioning; preferably, W ≥ 3, and they are not on a straight line;

[0140] Step S3122: The powder feeding cylinder delivers a certain amount of metal powder, which is spread onto the working platform by the powder spreading roller and the scraper;

[0141] Step S3123: using laser as an energy source, scanning the current layer according to the path planned in the slicing model of step S1, and completing the laser selective melting molding of the current layer by melting and solidifying the scanned metal powder;

[0142] Step S3124: After the scanning is completed, the working platform descends by a layer and continues to print the next layer;

[0143] When printing a layer of slices containing fibers, printing is performed according to the above steps S3121 to S3124; when printing a layer of slices not containing fibers, printing is performed according to steps S3122 to S3124; until the last layer of slices is printed, a metal-based composite material product is obtained.

[0144] Preferably, the metal-based composite material product is taken out, and the residual powder on the surface and inside of the product is removed by sandblasting or high-pressure gas treatment, and the product is cleaned.

[0145] In one possible design, before 3D printing, a substrate is installed on the working platform of the molding cavity to provide a growth plane for the metal powder, facilitate the smooth removal of the formed parts, and provide a heat dissipation base for the high-temperature melting process of the metal powder; the above-mentioned substrate design can also be applied to steps S302, S322, and S332.

[0146] In one possible design, during the 3D printing process, the molding cavity is evacuated and an inert protective gas, such as argon or nitrogen, is introduced to seal the molding cavity to prevent oxidation reactions during the high-temperature melting of the metal.

[0147] As an optional implementation, when the matrix material is a thermosetting resin, a selective photocuring method is used to perform additive manufacturing of thermosetting resin-based composite materials.

[0148] It can be understood that thermosetting resin is a resin that can be cross-linked and cured under heat or other conditions (such as laser, ultraviolet light), and its molecular structure is ultimately a network structure, and the change process is irreversible; thermosetting resin is suitable for selective photocuring molding or powder sintering molding, etc.; thermosetting resin includes high-temperature curing resin and photosensitive resin.

[0149] In one possible design, taking photosensitive resin as an example, a selective light curing molding method is used to perform additive manufacturing of thermosetting resin-based composite materials; specifically, the following steps are included:

[0150] Step S321: preparing photosensitive resin;

[0151] Purchase commercially available photosensitive resins that can be used for 3D printing;

[0152] Preferably, the viscosity of the purchased photosensitive resin is in the range of 10mPa·s-25mPa·s (temperature is 25°C); if the viscosity is too high, the printer nozzle is easy to be clogged, or it is not easy to lay evenly; if the viscosity is too low, the resin will flow directly from the printing workbench, which is not conducive to product molding.

[0153] It should be noted that the type of photosensitive resin can be selected as needed, including but not limited to epoxy resin, epoxy acrylate, polyurethane acrylate resin, polyester acrylate resin, amino acrylate resin, etc.

[0154] Step S322: Photocuring of selected areas;

[0155] The STL data file generated in step S1 is imported into the 3D printer system, and the photosensitive resin prepared in step S321 is placed in the material tank of the 3D printer to perform selective photocuring printing.

[0156] The printing equipment and specific process parameters of the selective photocuring molding can be selected and set from the parameters of the 3D printer and 3D printing molding technology in the prior art.

[0157] In one possible design, step S322 includes the following steps:

[0158] Step S3221: when printing a certain layer of slices containing fibers, the robot automatically picks up the two-dimensional fiber preform of the current layer, and accurately positions and places it by infrared scanning. After placing the two-dimensional fiber preform of the current layer, ultraviolet light is used to scan W points on the two-dimensional fiber preform for light curing positioning; preferably, W ≥ 3, and they are not on a straight line;

[0159] Step S3222: the photosensitive resin is evenly spread on the printing platform through the nozzle of the 3D printer, and then the current layer slice is scanned by the ultraviolet laser to solidify it sequentially from point to line and from line to surface, thus completing the selected area photocuring of the current layer;

[0160] Step S3223: the molding printing platform descends one layer and continues to print the next layer;

[0161] When printing a layer of slices containing fibers, printing is performed according to the above steps S3221 to S3223; when printing a layer of slices not containing fibers, printing is performed according to steps S3222 to S3223; until the last layer of slices is printed, a thermosetting resin-based composite material product is obtained.

[0162] As an optional implementation, when the matrix material is a thermoplastic resin, a fused deposition modeling method is used to perform additive manufacturing of the thermoplastic resin-based composite material.

[0163] It is understood that thermoplastic resins are easy to melt and can be softened by heating and then solidified by cooling. Therefore, thermoplastic resins are suitable for fused deposition modeling. Specifically, the following steps are included:

[0164] Step S331: preparing thermoplastic resin;

[0165] Procure commercially available thermoplastic resins that can be used for 3D printing;

[0166] Optionally, the type of thermoplastic resin can be selected as needed, including but not limited to acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polylactic acid (PLA), polyetheretherketone (PEEK), polyethylene terephthalate-1,4-cyclohexadiene dimethylene terephthalate (PETG), high-density polyethylene (HDPE), polystyrene (PS), etc.

[0167] Step S332: fused deposition modeling;

[0168] The STL data file generated in step S1 is imported into the 3D printer system, and the filament of the thermoplastic resin prepared in step S331 is delivered to the printer nozzle by the filament supply mechanism, and is heated and melted into a semi-liquid state at the nozzle for fused deposition molding.

[0169] The printing equipment and specific process parameters of fused deposition modeling can be selected and set from the parameters of 3D printers and 3D printing technology in the prior art.

[0170] In one possible design, step S332 includes the following steps:

[0171] Step S3321: when printing a certain layer of slices containing fibers, the robot automatically picks up the two-dimensional fiber preform of the current layer, and accurately positions and places it by infrared scanning. After placing the two-dimensional fiber preform of the current layer, laser scans W points on the two-dimensional fiber preform for melting and positioning; preferably, W ≥ 3, and they are not on a straight line;

[0172] Step S3322: The molten thermoplastic resin material is extruded through the nozzle of the 3D printer. According to the cross-sectional profile information of the corresponding layer slice given by the computer, the thermoplastic resin is selectively coated on the printing platform as the heated nozzle moves, and is quickly cooled and solidified.

[0173] Step S3323: The printer nozzle rises to the height of one slice layer and continues to print the next layer.

[0174] Among them, when printing a layer of slices containing fibers, printing is performed according to the above steps S3321 to S3323; when printing a layer of slices not containing fibers, printing is performed according to steps S3322 to S3323; until the last layer of slices is printed, a thermoplastic resin-based composite material product is obtained.

[0175] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and comparative examples.

[0176] Example 1

[0177] This embodiment provides an additive manufacturing method for continuous silicon carbide fiber reinforced silicon carbide (SiC / SiC composite material) turbine blades.

[0178] like Figure 2 , Figure 3 and Figure 4 The turbine blade 200 includes a blade 2 and a mounting base 3; the blade 2 includes a blade root 21, a blade tip 23, and a blade body 22 extending axially (i.e., in the Y direction) between the blade root 21 and the blade tip 23; the blade 2 is a crescent-shaped hollow structure along a section (i.e., an XZ plane) perpendicular to the axial direction (i.e., in the Y direction), and the bending direction of the crescent is the X direction; the mounting base 3 is a trapezoidal hollow structure, and the upper end face and the lower end face along the XY plane respectively include three tenons, and the surface with the largest area in the mounting base 3 is connected to the blade 2; a two-dimensional fiber fabric distributed along the XY plane is distributed in the turbine blade 200; the blade tip 23 of the blade 2 includes a groove 24, the wall thickness of the groove 24 is the same, and the wall thickness of the blade body 22 is the same as the wall thickness of the groove 24; four circular air holes are opened on the groove 24 of the blade 2.

[0179] The material of the turbine blade 200 is silicon carbide reinforced with continuous silicon carbide fibers, that is, SiC / SiC composite material.

[0180] The additive manufacturing method of the turbine blade 200 comprises the following steps:

[0181] Step S1: Use UG (Unigraphics NX) software to design and model to form a three-dimensional model of the turbine blade, such as Figure 2 , Figure 3 , Figure 4 ; Convert the 3D model into the STL triangulated file required by the additive manufacturing system, set the slice thickness to 0.1 mm, determine the XY plane of the turbine blade (that is, the plane where each layer of the 2D fiber fabric is located) as the base plane of 3D printing, set the Z direction perpendicular to the XY plane as the layer-by-layer stacking direction, and perform the slicing operation on the 3D model; Figure 5 A schematic cross-sectional diagram showing a slice of a turbine blade, with red representing the cut surface and the remaining grey representing the non-cut surface (i.e., the surface).

[0182] The total length of the turbine blade 200 in the Y direction (i.e., the axial direction) is 120 mm, the total length in the Z direction is 73 mm, and the total length in the X direction is 50 mm. According to the length of 73 mm in the Z direction, the slice thickness is 0.1 mm, and the total number of slices is 730 layers. In this embodiment, a total of 4 layers of two-dimensional fiber fabrics are provided, and the positions of these 4 layers of fabrics in the Z direction are respectively at the 200th, 300th, 400th, and 500th layers of the printed slices, ensuring that the outer contour of each layer of two-dimensional fiber fabric is 0.2 mm smaller than the outer contour of the slice where the corresponding layer of two-dimensional fiber fabric is located, so that the 4 layers of two-dimensional fiber fabrics can be fully covered in the corresponding slice shape.

[0183] Step S2, prefabricating two-dimensional fiber fabrics in layers;

[0184] Step S21: Select fiber bundles 0.12K (each bundle has 120 silicon carbide filaments) and silicon carbide fibers with a single filament diameter of 8 μm, and prepare silicon carbide two-dimensional fiber fabrics by weaving, such as Figure 6 As shown, the fibers in the two-dimensional fiber fabric are mainly distributed along the Y direction, and a smaller amount of fibers are distributed along the X direction, which plays a role in linking and fixing the Y-direction fibers; such a setting is mainly considered that the main force direction of the turbine blade is the Y direction;

[0185] Step S22: Before 3D printing, the silicon carbide two-dimensional fiber fabric is pretreated by spraying and rolling prepreg method. Specifically, a layer of epoxy resin liquid (curing temperature is 120°C) is sprayed on the surface of the silicon carbide two-dimensional fiber fabric, and then the silicon carbide two-dimensional fiber fabric fully soaked in the epoxy resin liquid is squeezed by a rotating pair of rollers through a rolling method, and the rollers are heated to 60°C at the same time to achieve low-temperature precuring to obtain a two-dimensional fiber preform with a certain shape and rigidity. By controlling the spraying amount and / or rolling parameters, it is ensured that the two-dimensional fiber fabric is fully soaked, combined and compacted with the epoxy resin liquid, and the thickness of the two-dimensional fiber preform is ensured to be less than 0.1mm;

[0186] Step S23: according to the outer contours of the 200th, 300th, 400th and 500th layers of slices, the two-dimensional fiber preform is cut by a CNC cutting machine, and each layer of the two-dimensional fiber fabric is ensured to be 0.2 mm smaller than the outer contour of the corresponding layer of slices during cutting, so as to obtain a four-layer two-dimensional fiber preform of the desired shape.

[0187] Step S301: preparing ceramic slurry;

[0188] Commercially available silicon carbide ceramic slurry that can be used for 3D printing is purchased, the ceramic powder is SiC ceramic, and the photosensitive resin is epoxy resin.

[0189] Step S302: Selected area light-curing molding;

[0190] Step S3021: When printing a certain layer of slices containing fibers, the robot automatically picks up the two-dimensional fiber preform of the current layer, and accurately positions and places it through infrared scanning. After placing the two-dimensional fiber preform of the current layer, ultraviolet light is used to scan four points on the two-dimensional fiber preform (not on a straight line) for light curing positioning, so that the two-dimensional fiber preform is fixed on the printed previous layer;

[0191] Step S3022: the peristaltic feeding system controls the quantitative supply of silicon carbide ceramic slurry;

[0192] Step S3023: The precision scraper motion system flattens the silicon carbide ceramic slurry in step S3022;

[0193] Step S3024: Scan the slice of the current layer with ultraviolet light to solidify it sequentially from point to line and from line to surface, thus completing the light curing of the current layer;

[0194] Step S3025: The molding printing platform descends one layer, and the precision scraper motion system returns to continue printing the next layer.

[0195] Among them, the 200th, 300th, 400th and 500th layers are slice layers containing two-dimensional fiber fabrics, and 3D printing is performed according to the above steps S3021 to S3025. The remaining layers repeat steps S3022 to S3025 for 3D printing until the last layer of slices is printed to obtain the precursor of the turbine blade.

[0196] Step S303: Place the turbine blade precursor into a degreasing furnace with a degreasing temperature of about 500°C and a degreasing time of 120 minutes, so that the epoxy resin and the like in the turbine blade precursor can be volatilized and completely discharged; perform hot isostatic pressing on the degreased turbine blade precursor with a sintering temperature of 1600°C to 2000°C and a nitrogen filling pressure of 100MPa, and keep the temperature and pressure for 24 hours to obtain the final SiC / SiC composite turbine blade.

[0197] The silicon carbide ceramic density of the turbine blade obtained in this embodiment can exceed 95%, the bending strength can reach more than 600 MPa, and it can withstand an ambient temperature of more than 1700°C, which can fully meet the use requirements of high-performance engines.

[0198] Embodiment 2:

[0199] This embodiment provides an additive manufacturing method for a continuous carbon fiber reinforced aluminum alloy composite tensile test piece.

[0200] like Figure 7 The size and structure of the tensile test piece are in accordance with the mechanical properties test standard GB3354-2014, such as Figure 8 and Fig. 9As shown, four reinforcing sheets 702 are attached to the clamped parts at both ends of the tensile test piece 701 for protection to prevent the huge clamping force during the tensile test from damaging the test piece itself. The tensile test piece 701 is formed by 3D printing, and the reinforcing sheet 702 is formed by traditional machining, and then the reinforcing sheet 702 and the tensile test piece 701 are firmly bonded together by a bonding process. Among them, the tensile test piece 701 includes an aluminum alloy matrix and a two-dimensional fiber fabric distributed in the XY plane (that is, the two-dimensional fiber fabric is stacked layer by layer along the Z direction perpendicular to the XY plane). The material of the tensile test piece 701 is a continuous carbon fiber reinforced aluminum alloy composite material.

[0201] The additive manufacturing method of the tensile test piece 701 comprises the following steps:

[0202] Step S1: using UG (Unigraphics NX) software to design and model, forming a three-dimensional model of the tensile test piece; converting the three-dimensional model of the tensile test piece into an STL triangulated file required by the additive manufacturing system, setting the slice thickness to 0.1 mm, determining the XY plane of the tensile test piece (that is, the plane where each layer of two-dimensional fiber fabric is located) as the base plane of 3D printing, setting the Z direction perpendicular to the XY plane as the layer-by-layer stacking direction, and performing a slice operation on the three-dimensional model; Fig. 9 Cross-sectional view showing a slice through a layer of a 2D fiber fabric contained in a tensile test piece.

[0203] The main dimensions of the tensile test piece 701 include: total length of 200mm, effective test section length of 55mm, effective test section width of 10mm, test piece thickness (i.e., Z-direction dimension) of 4mm; according to the Z-direction dimension of 4mm, the slice thickness is 0.1mm, and the total number of slices is 40 layers. In this embodiment, a total of 38 layers of two-dimensional fiber fabrics are provided, and the positions of these 38 layers of fabrics in the Z direction are respectively located at the 2nd layer, 3rd layer, 4th layer, ... 38th layer, and 39th layer of the printed slices, ensuring that the outer contour size of each layer of two-dimensional fiber fabric is 0.2mm smaller than the outer edge of the product of the corresponding layer of slices, so that each layer of carbon fiber two-dimensional fabric can be fully covered in the corresponding slice shape.

[0204] Step S2, prefabricating two-dimensional fiber fabrics in layers;

[0205] Step S21: Select a fiber tow 1K (each tow has 1000 carbon fiber filaments), a T800 carbon fiber with a filament diameter of 5 μm, and prepare a two-dimensional carbon fiber fabric by weaving, ensuring that the thickness of the obtained carbon fiber two-dimensional fabric is less than 0.1 mm; Fig. 9As shown, the fibers in the two-dimensional fabric are mainly distributed along the X direction, and a smaller amount of fibers are distributed along the Y direction, which plays a role in linking and fixing the X-direction fibers; this arrangement is mainly considered to be the main force direction of the test piece 701 is the tensile direction (ie, the X direction).

[0206] Step S22: Before 3D printing, the carbon fiber two-dimensional fabric is pretreated by hot melt rolling prepreg method. Specifically, the carbon fiber two-dimensional fabric is immersed in molten 7075 aluminum alloy liquid, and then the two-dimensional fabric of the carbon fiber soaked in the 7075 aluminum alloy liquid is squeezed by a rotating pair of rollers through a rolling method to ensure that the carbon fiber and the 7075 aluminum alloy liquid are fully soaked, combined and compacted. After cooling at room temperature, a two-dimensional fiber preform with a certain shape and rigidity is obtained. By controlling the immersion (for example, the temperature of the aluminum alloy, the immersion time) and / or rolling parameters, the thickness of the two-dimensional fiber preform is ensured to be less than 0.1 mm.

[0207] Step S23: Since the slices of the tensile test piece 701 along the Z direction have the same cross-sectional shape, the two-dimensional fiber preform of step S22 is cut by a CNC cutting machine according to the outer contour of any one of the slices. During cutting, it is ensured that each layer of the two-dimensional fiber preform is 0.2 mm smaller than the outer contour of the corresponding layer of slices, so as to obtain 38 layers of two-dimensional fiber preforms of the required shape.

[0208] Step S311: purchasing 7075 aluminum alloy powder for 3D printing;

[0209] Step S312: laser selective melting forming;

[0210] Import the STL data file generated in step S1 into the 3D printer system, put the 7075 aluminum alloy powder prepared in step S311 into the trough of the 3D printer, and perform 3D printing according to the laser selective melting molding process. The specific steps are as follows:

[0211] Step S3121: When printing a certain layer of slices containing carbon fiber, the robot automatically picks up the two-dimensional fiber preform of the current layer and accurately positions and places it through infrared scanning. After placing the two-dimensional fiber preform of the current layer, the laser is used to align four positioning points on the two-dimensional fiber preform (for example, Fig. 9 The first positioning point A, the second positioning point B, the third positioning point C, and the fourth positioning point D) located at the four vertices of the rectangle are laser melted and positioned, similar to the mechanism of metal spot welding, so that the two-dimensional fiber preform is fixed on the printed previous layer;

[0212] Step S3122: a certain amount of aluminum alloy powder is delivered by a powder delivery cylinder and spread onto a substrate on a workbench by a powder spreading roller and a scraper;

[0213] Step S3123: using laser as an energy source, scanning the current layer according to the path planned in the slicing model of step S1, and completing the laser selective melting forming of the current layer by melting and solidifying the scanned aluminum alloy powder;

[0214] Step S3124: After the scan is completed, the piston of the forming platform descends by a layer and continues to print the next layer.

[0215] Among them, the first layer (1st layer) and the last layer (40th layer) of the tensile test piece are pure 7075 aluminum alloy layers without fibers, and 3D printing is performed according to steps S3122 to S3124. The remaining 38 layers are sliced ​​layers containing carbon fiber two-dimensional fabrics. Steps S3121 to S3124 are repeated for 3D printing until the last layer of slices is printed to obtain the tensile test piece 701.

[0216] Mechanical properties test:

[0217] According to the relevant standards of tensile test (i.e. GB3354-2014), four reinforcing sheets 702 at both ends of the tensile test piece 701 are made by traditional machining process. The material of the reinforcing sheet 702 is 7075 aluminum alloy, the width of the reinforcing sheet 702 is 20 mm, and the thickness of the reinforcing sheet 702 is 1.5 mm. The four reinforcing sheets 702 and the tensile test piece 701 are firmly bonded together by bonding process.

[0218] The T800 continuous carbon fiber reinforced 7075 aluminum alloy composite material tensile test piece (including the reinforcement sheet) obtained in this embodiment was subjected to a tensile test in accordance with the relevant tensile test standard (GB3354-2014). The experimental results showed that the tensile strength of the tensile test piece in this embodiment was increased by more than 20% compared with that of the pure 7075 aluminum alloy test piece.

[0219] Embodiment 3:

[0220] This embodiment provides an additive manufacturing method for a continuous carbon fiber reinforced epoxy resin composite tensile test piece.

[0221] The difference between this embodiment and embodiment 2 is that the material of the substrate is epoxy resin, and the following steps are different:

[0222] Step S22: Before 3D printing, the carbon fiber two-dimensional fabric is pretreated by the glue tank rolling prepreg method. Specifically, the carbon fiber two-dimensional fabric is immersed in a glue tank containing epoxy resin liquid (curing temperature 120°C), and then the rolling method is used. The carbon fiber two-dimensional fabric soaked in epoxy resin liquid is squeezed by a rotating pair of rollers, and the rollers are heated to 60°C to achieve low-temperature precuring to obtain a two-dimensional fiber preform with a certain shape and stiffness. By controlling the immersion and / or rolling parameters, the carbon fiber and the epoxy resin liquid are fully wetted, combined and compacted to ensure that the thickness of the two-dimensional fiber preform is less than 0.1mm.

[0223] Step S321: purchasing epoxy resin for 3D printing;

[0224] Step S322: Photocuring of selected areas;

[0225] The STL data file generated in step S1 is imported into the 3D printer system, and the epoxy resin in step S321 is placed in the material tank of the 3D printer to perform selective photocuring printing. Specifically, the following steps are included:

[0226] Step S3221: When printing a slice containing carbon fiber, the robot automatically picks up the two-dimensional fiber preform of the current layer and accurately positions it through infrared scanning. After placing the two-dimensional fiber preform of the current layer, the robot scans four points on the two-dimensional fiber preform (such as Fig. 9 As shown in the figure), light-curing positioning is performed so that the two-dimensional fiber preform is fixed on the printed previous layer;

[0227] Step S3222: the epoxy resin is evenly spread on the printing platform through the nozzle of the 3D printer, and then the current layer slice is scanned by the ultraviolet laser to solidify it from point to line and from line to surface in sequence, thus completing the selected area photocuring of the current layer;

[0228] Step S3223: The molding printing platform descends one layer and continues to print the next layer.

[0229] Among them, the first layer (1st layer) and the last layer (40th layer) of the tensile test piece are pure epoxy resin layers, and 3D printing is performed according to steps S3222 to S3223. The remaining 38 layers are slice layers containing carbon fiber two-dimensional fabrics. Steps S3221 to S3223 are repeated for 3D printing until the last layer of slices is printed to obtain the tensile test piece 701.

[0230] Mechanical properties test:

[0231] According to the tensile test standard (i.e. GB3354-2014), four reinforcing sheets 702 at both ends of the tensile test piece are made by traditional machining process. The reinforcing sheet material is epoxy resin fiberglass. The width of the reinforcing sheet 702 is 20 mm, and the thickness of the reinforcing sheet 702 is 1.5 mm. The reinforcing sheet 702 and the tensile test piece 701 are firmly bonded together by using appropriate bonding process.

[0232] The tensile test piece (including the reinforcement sheet) of this embodiment was used to conduct a tensile test in accordance with the tensile test standard (GB3354-2014). The experimental results showed that the tensile strength of the epoxy resin composite material reinforced with T800 continuous carbon fiber (the fiber content of the test piece was about 40%) reached 700MPa, and the porosity was below 5%. If a higher tensile strength is required, the fiber content of the product can be further increased, and the fiber content can be as high as about 65%, and the corresponding product tensile strength can reach more than 1000MPa.

[0233] Embodiment 4:

[0234] This embodiment provides an additive manufacturing method for a continuous carbon fiber reinforced polyetheretherketone (PEEK) resin-based composite material.

[0235] The difference between this embodiment and embodiment 2 is that the material of the substrate is polyetheretherketone (PEEK) resin, and the following steps are different:

[0236] Step S22: Before 3D printing, the carbon fiber two-dimensional fabric is pretreated by a film hot pressing prepreg method. Specifically, a polyetheretherketone (PEEK) film with substantially the same plane shape is laid on the upper and lower surfaces of the carbon fiber two-dimensional fabric, and the polyetheretherketone (PEEK) plastic is melted by a high-temperature press plate and fully infiltrated and compacted with the carbon fiber to obtain a two-dimensional fiber preform with a certain shape and rigidity and a thickness of less than 0.1mm; the pressurizing temperature is 300°C, and the thickness of the polyetheretherketone (PEEK) film is 0.03mm.

[0237] Step S331: purchasing polyetheretherketone (PEEK) filament for 3D printing;

[0238] Step S332: forming by fused deposition method;

[0239] The STL data file generated in step S1 is imported into the 3D printer system, and the polyetheretherketone (PEEK) filament in step S331 is fed to the printer nozzle by the filament feeding mechanism, and heated and melted into a semi-liquid state at the nozzle for fused deposition molding. The specific steps are as follows:

[0240] Step S3321: When printing a certain layer of slices containing carbon fiber, the robot automatically picks up the two-dimensional fiber preform of the current layer and accurately positions and places it through infrared scanning. After placing the two-dimensional fiber preform of the current layer, the laser is used to align the four positioning points on the two-dimensional fiber preform (such as Fig. 9 As shown in the figure, laser melting positioning is performed, which is similar to the mechanism of metal spot welding, so that the two-dimensional fiber preform is fixed on the printed previous layer;

[0241] Step S3322: extruding the molten polyetheretherketone (PEEK) resin material through the nozzle of the 3D printer, and selectively coating the polyetheretherketone (PEEK) resin on the printing platform as the heated nozzle moves according to the cross-sectional profile information of the corresponding layer slice given by the computer, and rapidly cooling and solidifying;

[0242] Step S3323: The printer nozzle rises to the height of one slice layer and continues to print the next layer.

[0243] Among them, the first layer (1st layer) and the last layer (40th layer) of the tensile test piece are pure polyetheretherketone (PEEK) resin layers, and 3D printing is performed according to steps S3322 to S3323. The remaining 38 layers are sliced ​​layers containing carbon fiber two-dimensional fabrics, and steps S3321 to S3323 are repeated for 3D printing, thereby completing the printing of the tensile test piece 701.

[0244] Mechanical properties test:

[0245] According to the tensile test standard (GB3354-2014), four reinforcing plates 702 at both ends of the tensile test piece 701 are manufactured by traditional machining process. The reinforcing plate material is polyetheretherketone (PEEK) plastic, and the reinforcing plate 702 and the tensile test piece 701 are firmly combined together by hot melt welding process.

[0246] The tensile test piece (including the reinforcement sheet) of this embodiment was used to carry out a tensile test in accordance with the tensile test standard (GB3354-2014). The experimental results showed that the tensile strength of the polyetheretherketone (PEEK) composite material reinforced with T800 continuous carbon fiber could reach more than 500 MPa, and the porosity content was less than 5%.

[0247] Comparative Example 1:

[0248] Using the existing "prepreg fiber extrusion + thermoplastic resin melt deposition molding method", the production of Figure 7-Figure 9 The process of the tensile test piece shown (carbon fiber reinforced polyetheretherketone PEEK composite material) mainly includes:

[0249] Continuous carbon fiber and polyetheretherketone (PEEK) plastic are added to a heated melting chamber respectively, and then a mixture of continuous prepreg fibers and plastic is extruded through the nozzle of the melting chamber and laid out according to a predetermined route. After printing one layer, the continuous fibers are cut off and the next layer is printed. This cycle is repeated to complete the entire printing.

[0250] The biggest problem of the carbon fiber reinforced polyetheretherketone (PEEK) composite material obtained by the method provided in Comparative Example 1 is that the porosity is too high, which is above 20%. As a result, the mechanical properties are relatively low, and the tensile strength of the test piece is only about 220 MPa.

[0251] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for additive manufacturing of continuous fiber reinforced composite materials, characterized in that: The additive manufacturing method comprises the following steps: Step S1, establishing a three-dimensional model of a laminated composite material product, and performing slicing processing, wherein each layer of two-dimensional fiber fabric is included in a corresponding slice; the laminated composite material includes a matrix and a two-dimensional fiber fabric; Step S2, prefabricating two-dimensional fiber fabrics in layers: first prepare two-dimensional fiber fabrics, preform the two-dimensional fiber fabrics into two-dimensional fiber preforms by prepreg method, process the two-dimensional fiber preforms into two-dimensional fiber preforms of required shapes, and stack them in the order of slice printing for standby; Step S3, performing additive manufacturing of laminated composite products by 3D printing: when printing a certain layer of slices containing two-dimensional fiber fabrics, first accurately lay out the two-dimensional fiber preforms in the corresponding order, position them, and then lay out or spray the matrix material.

2. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: Step S1 includes the following steps: Step S11: using computer-aided design software to establish a three-dimensional model of the laminated composite material product; Step S12: convert the three-dimensional model of the laminated composite product into an STL triangulated file, set the XY plane where the two-dimensional fiber fabric is located as the base plane of 3D printing, set the Z direction perpendicular to the XY plane as the layer-by-layer stacking direction, and slice the STL triangulated file.

3. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S1, the slice thickness is greater than the thickness of the two-dimensional fiber fabric, satisfying N>M1, where N is the slice thickness and M1 is the maximum thickness of the two-dimensional fiber fabric.

4. The additive manufacturing method of continuous fiber reinforced composite material according to claim 2, characterized in that: In step S1, the first and last layers of the slice are matrix materials without fibers, satisfying N<S, where N is the slice thickness and S is the thickness of the matrix material on the upper and lower surfaces of the laminated composite product along the Z direction.

5. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: Step S2 includes the following steps: Step S21: preparing a two-dimensional fiber fabric by weaving; Step S22: using a pre-preg method to fully impregnate the two-dimensional fiber fabric with a setting agent and set the two-dimensional fiber fabric, thereby preforming the two-dimensional fiber preform into a two-dimensional fiber preform capable of being shaped; Step S23: Processing the two-dimensional fiber preform into a two-dimensional fiber preform of a required shape, and stacking them in the order of slice printing for standby use.

6. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S2, the fibers used to prepare the two-dimensional fiber fabric are ultra-small tow fibers and satisfy: M1≤M2<N; M1 is the maximum thickness of the two-dimensional fiber fabric, M2 is the maximum thickness of the two-dimensional fiber preform, and N is the slice thickness.

7. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S3, the main steps of accurately laying the two-dimensional fiber preforms in the corresponding order include: before laying or spraying a layer of substrate, accurately positioning the placement position of the two-dimensional fiber preforms of the corresponding layer of the substrate to be sprayed by infrared scanning.

8. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S3, the main steps of positioning include: selecting W positioning points on the two-dimensional fiber preform, scanning the positioning points with laser or ultraviolet light to perform melting, thermal curing or photocuring positioning.

9. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S2, when the matrix material is a thermosetting resin, the two-dimensional fiber fabric is preformed into a two-dimensional fiber preform by using a glue groove rolling prepreg method.

10. The additive manufacturing method of continuous fiber reinforced composite material according to claim 1, characterized in that: In step S2, when the matrix material is a thermoplastic resin, a thin film hot pressing prepreg method is used to preform the two-dimensional fiber fabric into a two-dimensional fiber preform.

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