Inner boss reinforced composite material component forming method based on 3D printing and fiber winding

Abstract

The invention discloses an inner boss reinforced composite material component forming method based on 3D printing and fiber winding, which comprises the following steps: assembling a forming die of an inner boss reinforced composite material component, and mounting the forming die on a positioner; 3D printing equipment and fiber winding equipment are adopted for forming a blank on a forming mold, and the fiber winding track of a boss reinforcement area in the blank is of a multi-layer spherical contour structure; and the obtained blank is cured, and the inner boss reinforced composite material component is obtained after mold removal. According to the special forming method for the reinforced composite material component containing the inner boss, high-quality forming of the component can be achieved, and the shear resistance and strength of the inner boss of the component can be remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material additive manufacturing, and specifically relates to a method for forming an inner boss reinforced composite material component based on 3D printing and fiber winding. Background Art

[0002] Composite fiber winding is a molding process for composite rotating components, which involves impregnating continuous fibers with resin and then winding them onto a core mold according to a certain pattern. It can efficiently and quickly manufacture rotating shells. Composite 3D printing is a process that combines fibers with resin to form printing filaments, and achieves integrated molding of complex structures by stacking them layer by layer according to a set motion path. It can efficiently manufacture composite components with complex shapes and structures that are difficult to achieve with traditional processes.

[0003] In the prior art, document CN2023117773805 discloses a large-opening composite engine casing deformation controllable winding combination mold, which includes a core shaft, a petal mold and a head. The petal mold is wrapped around the outside of the core shaft along the circumferential direction and fixed on the core shaft at both ends. The head is fastened by a nut. This patent designs a mold for a composite casing with an internal reinforced structure, but it is not suitable for internal bosses and reinforced composite casing structures.

[0004] Shell structures / components with internal bosses and reinforcements are widely used in aerospace, transportation and other industries. The use of carbon fiber composite materials to form complex shells has a light structure weight, which can reduce weight by more than 30% compared to aluminum alloys. The structure has high strength and its tensile strength can reach more than 3000MPa, which is much higher than ordinary steel. However, for complex structures / components with bosses and reinforcements inside, it is difficult to form composite shells with high quality through one-time winding, and based on conventional technical routes, mechanical processing is required to realize the manufacture of complex internal bosses and reinforcements, which will seriously damage the fiber continuity inside the structure and reduce the structural strength. More importantly, for complex structures / components with bosses and reinforcements inside, how to effectively implant fiber bundles in the bosses and within a range of 2-3mm deep on the inner wall surface of the component has always been a technical problem faced by this field. Summary of the invention

[0005] The present invention aims to provide a method for forming an internal boss reinforced composite material component based on 3D printing and fiber winding, which is used for high-quality forming of a composite material shell component containing bosses and reinforcements inside.

[0006] The present invention adopts the following technical solution.

[0007] A method for forming an inner boss reinforced composite material component based on 3D printing and fiber winding, the steps comprising: Step 1, assembling a forming die for an inner boss reinforced composite material component and installing it on a positioner; Step 2, forming a blank on a forming die using a 3D printing device and a fiber winding device, wherein the fiber winding trajectory of the inner boss reinforcement area presents a spherical contour structure of several layers; in the present invention, the spherical contour refers to a substantially spherical contour; Step 3, curing the obtained blank, and after demolding, obtaining an inner boss reinforced composite material component.

[0008] As a preferred embodiment, the forming mold includes: a core shaft, a core mold covering assembly is arranged on the periphery of the core shaft, and a semicircular groove, an elliptical groove, a reinforcement rib matching groove, a threaded rib matching groove, and an annular boss matching groove are arranged on the core mold covering assembly. The core mold covering assembly includes a flap mold one, a flap mold two, a flap mold three, a flap mold four, a flap mold five, and a flap mold six. The outer walls of these six flap molds together constitute the inner forming surface of the inner boss reinforced composite material component; end covers and sealing covers are arranged at both ends of the core mold covering assembly.

[0009] As a more preferred option, the inner arc contour width of the first split mold is greater than the outer arc contour width, and the inner arc contour widths of the other split molds are all smaller than the corresponding outer arc contour widths; the two ends of the core mold covering assembly are wedge-shaped cylindrical structures.

[0010] Furthermore, in order to effectively implant the fiber tow in the boss of the inner boss reinforced composite component, the steps of forming the blank on the forming mold using the 3D printing device and the fiber winding device include: Step 21, on the core mold covering component, the first part of the fiber tow is spaced and circumferentially wound at the location where the semicircular groove is located and the location where the elliptical groove is located, the fiber tow located in the semicircular groove and the elliptical groove has an arc-shaped structure, and the coverage of the first part of the fiber tow does not exceed 2 to 3 times the width of the semicircular groove or the elliptical groove; Step 22, axially printing a first linear composite material spaced apart at the location where the semicircular grooves are located and the location where the elliptical grooves are located, wherein the first linear composite material and the first portion of the fiber tows together form a first grid layer with a spherical contour; Step 23, continue printing and filling the dot-shaped composite material in the mesh area of ​​the first mesh layer, so that the first dot-shaped composite material and the first mesh layer together constitute a first composite material layer; Step 24, referring to Step 21 to Step 23, continue to intermittently and hoop-wind the fiber tows on the first composite material layer, print linear composite materials and dot composite materials, until an Nth composite material layer of a target thickness is formed; Step 25, continuously printing and filling the composite material on the Nth composite material layer until the composite material fills the entire semicircular groove and the elliptical groove and is compacted; Step 26, firstly axially laying fiber tows at intervals on the surface of the core mold covering component, and then continuing to print the composite material on the surface of the core mold covering component, so that the surface of the core mold covering component forms a shell structure with a thickness of 2-3 mm; Step 27, setting the tension and winding trajectory of the fiber winding equipment, and forming the structure of the remaining thickness by continuous fiber spiral + hoop winding the shell.

[0011] In order to be able to more stably implant the fiber bundle in the component boss in a directional manner, in step 21, during the process of winding the fiber bundle in an interval and annular direction, the tool head is used to press into the semicircular groove and the elliptical groove so that the wound fiber bundle can be close to the inner wall of the semicircular groove and the inner wall of the elliptical groove.

[0012] In order to more conveniently implant the fiber bundles in the boss in a directional manner, the tool head is composed of a plurality of detachable tool units, each of which can press down 1 to 3 fiber bundles.

[0013] As a preferred solution, the distance between adjacent fiber bundles of the first part is controlled to be 5 mm.

[0014] Furthermore, in order to effectively implant the fiber bundles within a depth of 2-3 mm on the inner wall surface of the component, the specific steps of first axially laying the fiber bundles on the surface of the core mold covering assembly in step 26 are as follows: first, the two ends of the fiber bundles of set length and stretched straight are clamped in the grooves on the end cover and the sealing cover, and the remaining fiber bundles at the ends are removed after the end of step 27.

[0015] As a preferred solution, the width of the slot is 0.9 times the diameter of the fiber bundle.

[0016] Furthermore, in order to more conveniently and effectively implant the fiber bundle within a range of 2-3 mm deep on the surface of the inner wall of the component, the grooves are arranged along the side walls and outer end walls of the end cap and the cover.

[0017] Beneficial effects: The present invention proposes a special forming method for composite components with internal boss reinforcements, which can not only achieve high-quality forming of such components, significantly improve the shear resistance and strength of the internal boss of the component, but also effectively implant fiber bundles in the boss of the component and within a range of 2-3 mm deep on the surface of the inner wall of the component. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is an axonometric schematic diagram of the forming mold in Example 1; Figure 2 is a schematic diagram of the main direction of the forming mold in Example 1; Figure 3 is a schematic cross-sectional (axial) view of the forming die in Example 1; Figure 4is a schematic cross-sectional (radial) view of the forming die in Example 1; Figure 5 is a schematic diagram of one of the split molds of the forming mold in Example 1; Figure 6 is a schematic diagram of a tool head (top view) of a forming die in Example 2; Figure 7 is a partial isometric schematic diagram of the forming mold in Example 2; Figure 8 It is a schematic diagram of the cross section (axial direction) of the forming mold in Example 2, showing the state of the fiber bundle laid in the groove. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Example 1

[0020] Combination Figures 1 to 5 As shown, a method for forming an inner boss reinforced composite material component based on 3D printing and fiber winding comprises the following steps: Step 1, assembling a forming die of the inner boss reinforced composite material component and installing it on a positioner, which refers to a machine or device used to adjust the posture and position of a workpiece; Wherein, the forming mold comprises: a core shaft 1, a core mold covering component 3 is arranged on the periphery of the core shaft 1, a semicircular groove 3021, an elliptical groove 3022, a reinforcing rib matching groove 3023, a threaded rib matching groove 3024, and an annular boss matching groove 3025 are arranged on the core mold covering component 3, the core mold covering component 3 comprises a flap mold 1 301, a flap mold 2 302, a flap mold 3 303, a flap mold 4 304, a flap mold 5 305, and a flap mold 6 306, and the outer walls of these six flap molds together constitute the inner forming surface of the inner boss reinforced composite material component; end covers 2 and sealing covers 4 are arranged at both ends of the core mold covering component 3; the inner arc contour width of the flap mold 1 301 is greater than the outer arc contour width, and the inner arc contour widths of the other flap molds are all smaller than the corresponding outer arc contour widths; the two ends of the core mold covering component 3 are wedge-shaped cylindrical structures; Step 2, using 3D printing equipment and fiber winding equipment to form a blank on a forming mold, wherein the fiber winding trajectory of the inner boss reinforcement area presents a spherical contour structure of several layers; specifically: Step 21, on the core mold covering component 3, the first part of the fiber tow is spaced and circumferentially wound at the location of the semicircular groove 3021 and the location of the elliptical groove 3022, the fiber tow located in the semicircular groove 3021 and the elliptical groove 3022 is in an arc-shaped structure, the coverage of the first part of the fiber tow does not exceed 2 to 3 times the width of the semicircular groove 3021 or the elliptical groove 3022, and the spacing between adjacent tows of the first part of the fiber tow is controlled to be 5 mm; Step 22, axially printing the first linear composite material spaced apart at the location of the semicircular groove 3021 and the location of the elliptical groove 3022, the first linear composite material and the first part of the fiber tows together forming a first grid layer with a spherical contour; Step 23, continue printing and filling the dot-shaped composite material in the mesh area of ​​the first mesh layer, so that the first dot-shaped composite material and the first mesh layer together constitute a first composite material layer; Step 24, referring to Step 21 to Step 23, continue to intermittently and hoop-wind the fiber tows on the first composite material layer, print linear composite materials and dot composite materials, until an Nth composite material layer of a target thickness is formed; Step 25, continuously printing and filling the composite material on the Nth composite material layer until the composite material fills the entire semicircular groove 3021 and the elliptical groove 3022, and compacts them; Step 26, first axially laying fiber bundles at intervals on the surface of the core mold covering component 3, and then continuing to print the composite material on the surface of the core mold covering component 3, so that the shell structure 6 with a thickness of 2-3mm is formed on the surface of the core mold covering component 3; Step 27, setting the tension and winding trajectory of the fiber winding equipment, and forming the remaining thickness structure by continuous fiber spiral + hoop winding shell; Step 3, curing the obtained blank, and after demolding, obtaining an inner boss reinforced composite material component.

[0021] The inner boss reinforced composite material component formed by the scheme in this embodiment uses T700-12k carbon fiber and epoxy resin composite material as winding fiber materials, and T800-3k carbon fiber PEEK prepreg as composite material for 3D printing. The maximum diameter of the component is 150mm and the minimum diameter is 142mm. The boss height corresponding to the semicircular groove 3021 is 12mm and the radius is 20mm. The boss height corresponding to the elliptical groove 3022 is 15mm, the radius is 10mm, and the length is 40mm. The obtained component was tested, and the results showed that the boss compressive strength corresponding to the semicircular groove 3021 was 452Mpa and the shear strength was 56Mpa; the boss compressive strength corresponding to the elliptical groove 3022 was 389Mpa and the shear strength was 78Mpa. Example 2

[0022] Combination Figures 1 to 7 As shown, a method for forming an inner boss reinforced composite material component based on 3D printing and fiber winding comprises the following steps: Step 1, assembling a forming die of the inner boss reinforced composite material component and installing it on a positioner, which refers to a machine or device used to adjust the posture and position of a workpiece; Wherein, the forming mold comprises: a core shaft 1, a core mold covering component 3 is arranged on the periphery of the core shaft 1, a semicircular groove 3021, an elliptical groove 3022, a reinforcing rib matching groove 3023, a threaded rib matching groove 3024, and an annular boss matching groove 3025 are arranged on the core mold covering component 3, the core mold covering component 3 comprises a flap mold 1 301, a flap mold 2 302, a flap mold 3 303, a flap mold 4 304, a flap mold 5 305, and a flap mold 6 306, and the outer walls of these six flap molds together constitute the inner forming surface of the inner boss reinforced composite material component; end covers 2 and sealing covers 4 are arranged at both ends of the core mold covering component 3; the inner arc contour width of the flap mold 1 301 is greater than the outer arc contour width, and the inner arc contour widths of the other flap molds are all smaller than the corresponding outer arc contour widths; the two ends of the core mold covering component 3 are wedge-shaped cylindrical structures; such as Figure 7 As shown, a plurality of slots 7 are arranged at intervals on the end cover 2 and the cover 4. The slots 7 are arranged along the side walls and outer end walls of the end cover 2 and the cover 4. Each slot 7 can clamp a fiber bundle 8 at the same depth. Step 2, using 3D printing equipment and fiber winding equipment to form a blank on a forming mold, wherein the fiber winding trajectory of the inner boss reinforcement area presents a spherical contour structure of several layers; specifically: Step 21, on the core mold covering component 3 and at the location of the semicircular groove 3021 and the elliptical groove 3022, the first part of the fiber tow is wound in an annular manner at intervals, the fiber tow located in the semicircular groove 3021 and the elliptical groove 3022 is in an arc-shaped structure, the coverage of the first part of the fiber tow does not exceed 2 to 3 times the width of the semicircular groove 3021 or the elliptical groove 3022, and the spacing between adjacent tows of the first part of the fiber tow is controlled to be 5 mm; in the process of winding the fiber tow in an annular manner, the tool head 6 is pressed into the semicircular groove 3021 and the elliptical groove 3022 so that the wound fiber tow can be close to the semicircular groove 3021 of the groove. 21 inner wall and the inner wall of the oval groove 3022, the tool head 6 used is composed of a plurality of detachable tool monomers 11, each tool monomer 11 can press down 1 to 3 fiber bundles (each time 1 to 3 turns of the fiber bundle are wound, a tool monomer 11 is inserted until all the tool monomers 11 are inserted and the state is maintained for 5 to 10 seconds before the tool head 6 is taken out), and a holding rod 10 is provided on the tool monomer 11; in this step, the tool head 6 mainly plays the role of: ensuring that the fiber bundle has enough margin to bend / concave, and the wound fiber bundle can be close to the inner wall of the semicircular groove and the inner wall of the oval groove by pressing the tool head into the semicircular groove and the oval groove; Step 22, axially printing the first linear composite material spaced apart at the location of the semicircular groove 3021 and the location of the elliptical groove 3022, the first linear composite material and the first part of the fiber tows together forming a first grid layer with a spherical contour; Step 23, continue printing and filling the dot-shaped composite material in the mesh area of ​​the first mesh layer, so that the first dot-shaped composite material and the first mesh layer together constitute a first composite material layer; Step 24, referring to Step 21 to Step 23, continue to intermittently and hoop-wind the fiber tows on the first composite material layer, print linear composite materials and dot composite materials, until an Nth composite material layer of a target thickness is formed; Step 25, continuously printing and filling the composite material on the Nth composite material layer until the composite material fills the entire semicircular groove 3021 and the elliptical groove 3022, and compacts them; Step 26, first axially laying fiber bundles at intervals on the surface of the core mold covering component 3, and then continuing to print the composite material on the surface of the core mold covering component 3, so that the shell structure 6 with a thickness of 2-3mm is formed on the surface of the core mold covering component 3; The specific steps of laying the fiber bundles axially and spaced apart on the surface of the core mold coating component 3 in this step are as follows: first, the two ends of the fiber bundles 8 of set length and stretched are clamped in the clamping grooves 7 on the end cover 2 and the cover 4, and the residual fiber bundles at the ends are removed after the step 27 is completed; the width of the clamping groove 7 is 0.9 times the diameter of the fiber bundle (this technical point is very critical, and its function includes being able to quickly clamp and fix the fiber bundles 8 in a stretched state); In addition, when more layers of fiber tows 8 need to be laid in the 2-3 mm shell structure 6, a layer of composite material can be printed after each layer of fiber tows 8 is laid; Step 27, setting the tension and winding trajectory of the fiber winding equipment, and forming the remaining thickness structure by continuous fiber spiral + hoop winding shell; Step 3, curing the obtained blank, and after demolding, obtaining an inner boss reinforced composite material component.

[0023] The inner boss reinforced composite material component formed by the scheme in this embodiment is T700-12k carbon fiber and epoxy resin composite material used for winding fiber materials, T800-3k carbon fiber PEEK prepreg filament used for 3D printing, the maximum diameter of the component is 150mm, the minimum diameter is 142mm, the boss height corresponding to the semicircular groove 3021 is 12mm, the radius is 20mm, the boss height corresponding to the elliptical groove 3022 is 15mm, the radius is 10mm, and the length is 40mm. The obtained component was tested, and the results showed that the boss compressive strength corresponding to the semicircular groove 3021 was 486Mpa, and the shear strength was 67.5Mpa; the boss compressive strength corresponding to the elliptical groove 3022 was 439Mpa, and the shear strength was 87Mpa.

[0024] The present invention proposes a special forming method for a composite material component reinforced with an inner boss, which can not only achieve high-quality forming of such components, but also significantly improve the shear resistance and strength of the inner boss of the component. In particular, the scheme in Example 2 can effectively implant fiber bundles in the boss of the component and within a range of 2-3 mm deep on the surface of the inner wall of the component (while the prior art has not been able to solve this technical problem). Of course, the fiber bundles 8 can also be adjusted to other depth positions of the slot 7 to achieve effective implantation of the fiber bundles at other depth positions in the component.

Claims

1. A method for forming an inner boss reinforced composite material component based on 3D printing and fiber winding, characterized in that the steps include: Step 1, assembling a forming die for an inner boss reinforced composite material component and installing it on a positioner; Step 2, using a 3D printing device and a fiber winding device to form a blank on a forming mold, wherein the fiber winding trajectory of the inner boss reinforcement area presents a spherical contour structure of several layers; Step 3, curing the obtained blank, and after demolding, obtaining an inner boss reinforced composite material component.

2. The method for forming an inner boss reinforced composite material component according to claim 1, characterized in that: The forming die comprises: a core shaft (1), a core mold covering component (3) is arranged on the periphery of the core shaft (1), a semicircular groove (3021), an elliptical groove (3022), a reinforcing rib matching groove (3023), a threaded rib matching groove (3024), and an annular boss matching groove (3025) are arranged on the core mold covering component (3), the core mold covering component (3) comprises a flap mold one (301), a flap mold two (302), a flap mold three (303), a flap mold four (304), a flap mold five (305), and a flap mold six (306), and the outer walls of the six flap molds together constitute the inner forming surface of the inner boss reinforced composite material component; end covers (2) and sealing covers (4) are arranged at both ends of the core mold covering component (3).

3. The method for forming an inner boss reinforced composite material component according to claim 2, characterized in that: The inner arc profile width of the first split mold (301) is greater than the outer arc profile width, and the inner arc profile widths of the other split molds are all smaller than the corresponding outer arc profile widths; the two ends of the core mold covering component (3) are wedge-shaped cylindrical structures.

4. The method for forming an inner boss reinforced composite material component according to claim 3, characterized in that: The steps of forming a blank on a forming die using a 3D printing device and a filament winding device include: Step 21, winding the first part of the fiber bundles in an annular manner at intervals on the core mold covering component (3) and at the location where the semicircular groove (3021) and the elliptical groove (3022) are located, wherein the fiber bundles located in the semicircular groove (3021) and the elliptical groove (3022) have an arc-shaped structure, and the coverage of the first part of the fiber bundles does not exceed 2 to 3 times the width of the semicircular groove (3021) or the width of the elliptical groove (3022); Step 22, axially printing a first linear composite material spaced apart at the location where the semicircular groove (3021) and the elliptical groove (3022) are located, wherein the first linear composite material and the first portion of the fiber tows together form a first grid layer with a spherical contour; Step 23, continue printing and filling the dot-shaped composite material in the mesh area of ​​the first mesh layer, so that the first dot-shaped composite material and the first mesh layer together constitute a first composite material layer; Step 24, referring to Step 21 to Step 23, continue to intermittently and hoop-wind the fiber tows on the first composite material layer, print linear composite materials and dot composite materials, until an Nth composite material layer of a target thickness is formed; Step 25, continuously printing and filling the composite material on the Nth composite material layer until the composite material fills the entire semicircular groove (3021) and the elliptical groove (3022), and compacts them; Step 26, first axially laying fiber bundles at intervals on the surface of the core mold covering component (3), and then continuing to print the composite material on the surface of the core mold covering component (3), so that a shell structure (6) with a thickness of 2-3 mm is formed on the surface of the core mold covering component (3); Step 27, setting the tension and winding trajectory of the fiber winding equipment, and forming the structure of the remaining thickness by continuous fiber spiral + hoop winding the shell.

5. The method for forming an inner boss reinforced composite material component according to claim 4, characterized in that: In step 21, during the process of winding the fiber bundle in an intermittent and annular direction, the tool head (9) is used to press into the semicircular groove (3021) and the elliptical groove (3022) so that the wound fiber bundle can be close to the inner wall of the semicircular groove (3021) and the inner wall of the elliptical groove (3022).

6. The method for forming an inner boss reinforced composite material component according to claim 5, characterized in that: The tool head (9) is composed of a plurality of detachable tool units (11) spliced ​​together, and each tool unit (11) is capable of pressing down 1 to 3 fiber bundles.

7. The method for forming an inner boss reinforced composite material component according to claim 6, characterized in that: The distance between adjacent fiber bundles of the first part is controlled to be 5 mm.

8. The method for forming an inner boss reinforced composite material component according to claim 7, characterized in that: The specific steps of axially laying the fiber bundles at intervals on the surface of the core mold coating component (3) in step 26 are: first, the two ends of the fiber bundles of set length and stretched straight are clamped into the clamping grooves (7) on the end cover (2) and the cover (4), and after the end of step 27, the remaining fiber bundles at the ends are removed.

9. The method for forming an inner boss reinforced composite material component according to claim 8, characterized in that: The width of the slot (7) is 0.9 times the diameter of the fiber bundle.

10. The method for forming an inner boss reinforced composite material component according to claim 9, characterized in that: The card slot (7) is arranged along the side walls and outer end walls of the end cover (2) and the sealing cover (4).

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