A method for manufacturing a composite material part of a pointed conical cavity thin-walled structure

Abstract

The application discloses a manufacturing method of a sharp-cone cavity thin-wall structure composite part, which is based on the characteristics of a fused deposition forming process, optimizes the structure of a sharp-cone part structure model, sets a filling body in a hollow interlayer midpoint array between an inner wall and an outer wall, then places the sharp-cone part structure model upside down, prints the sharp-cone cavity thin-wall structure composite part in sequence from bottom to top and from outside to inside, thereby improving the overall strength of the part, meeting the strength requirement of the part, and changing the traditional mold forming of the part into moldless forming, and changing the manual laying into digital forming, improving the manufacturing quality and the qualified rate of the part, reducing the production cost, and shortening the overall manufacturing cycle.

Description

Technical Field

[0001] This invention belongs to the technical field of 3D printing, specifically relating to a method for manufacturing composite material parts with a pointed conical cavity thin-walled structure. Background Technology

[0002] Composite materials, characterized by high strength, light weight, and multifunctionality, have been widely applied in structural or functional components of aircraft, such as fuselages, tails, and leading edges, achieving functional and performance enhancements, as well as weight reduction. Based on different application scenarios, they are mainly divided into two categories: functional composite materials and structural composite materials. Functional composite materials primarily meet the diverse functional application requirements of aircraft structural components, such as radar-absorbing coatings, radar-absorbing honeycomb cores, and smart skin radomes. Structural composite materials primarily meet the application requirements of lightweight and high-strength structural components for aircraft, with mechanical properties reaching or exceeding those of aluminum alloys. They are mainly represented by wings, skins, supporting frames, and various protective shields. Thin-walled composite material parts with pointed conical cavities belong to the category of structural composite material parts. They are formed using the current mainstream vacuum bag-autoclave method, relying on mold forming. This method presents difficulties in forming, resulting in poor dimensional and surface quality of the formed parts, leading to a low manufacturing qualification rate.

[0003] Therefore, in view of the above-mentioned technical problems existing in the preparation of thin-walled composite material parts with pointed conical cavities using the vacuum bag-autoclave method in the prior art, the present invention discloses a method for manufacturing thin-walled composite material parts with pointed conical cavities. Summary of the Invention

[0004] This invention discloses a method for manufacturing a conical hollow thin-walled composite material part. By optimizing the structural model of the conical part, a lattice of fillers is set in the hollow interlayer of the conical part structural model for support, and fused deposition modeling is used to prepare the conical hollow thin-walled composite material part using short-cut carbon fiber composite filaments as raw material. This method improves the manufacturing efficiency while effectively ensuring the forming qualification rate of the conical hollow thin-walled composite material part.

[0005] This invention is achieved through the following technical solution:

[0006] A method for manufacturing a thin-walled composite material part with a pointed conical cavity structure includes the following steps:

[0007] Step 1: Prepare chopped carbon fiber composite filaments, wherein the chopped carbon fiber composite filaments are composited with short carbon fibers as the reinforcing phase and polyetheretherketone as the resin matrix;

[0008] Step 2: Design the structural model of the cone-shaped part. The structural model of the cone-shaped part includes an inner wall, an outer wall, and a hollow interlayer disposed between the inner wall and the outer wall. The hollow interlayer is filled with a filler material.

[0009] Step 3: Place the cone-shaped part structure model upside down and add a serrated support structure to the bottom outer side of the cone-shaped part structure model to generate the final process model.

[0010] Step 4: According to the process model, the short-cut carbon fiber composite filament is printed into a cone-shaped part by fused deposition modeling in the order of printing the outer wall, placing the filler, and printing the inner wall.

[0011] Step 5: Remove the supporting structure on the outside of the cone part, grind the outer wall, and then put the cone part into an oven for heat treatment.

[0012] To better realize the present invention, the thickness of the inner wall is 1-1.2 mm, the thickness of the outer wall is 1-1.2 mm, and the filler is a helical icosahedron.

[0013] To better realize the present invention, the spiral icosahedron further includes a plurality of spiral walls, the thickness of the spiral walls is 0.3-0.5 mm, and the wall spacing between adjacent spiral walls is 3-5 mm.

[0014] To better realize the present invention, the diameter of the chopped carbon fiber composite filament is less than or equal to 1.75 mm.

[0015] To better realize the present invention, further, during the printing process of the cone-shaped part, the printing line width is less than or equal to 0.4 mm, the printing layer is less than or equal to 0.15 mm, and the printing speed is 20-40 mm / s.

[0016] To better realize the present invention, the overlap rate between printed lines is less than or equal to 10%.

[0017] To better realize the present invention, the spacing between adjacent support structures is less than or equal to 2.5 mm.

[0018] To better realize the present invention, the heat treatment temperature is greater than or equal to 280°C, the heat treatment holding time is greater than or equal to 120 min, and the heating rate of the heat treatment process is less than or equal to 5°C / min.

[0019] To better realize the present invention, the short carbon fiber powder and polyether ether ketone powder are further dried, and then the short carbon fiber powder and polyether ether ketone powder are mixed and dispersed by physical mixing. The mixed powder is then dried again, and the dried mixed powder is heated and melted by a twin-screw extruder and extruded to obtain short-cut carbon fiber composite filaments.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] Based on the characteristics of fused deposition modeling (FDM) technology, this invention optimizes the structure of a conical part model. A lattice of filler is placed in the hollow interlayer between the inner and outer walls. The conical part model is then inverted and printed from bottom to top and from outside to inside to obtain a thin-walled, conical cavity composite material part. This improves the overall strength of the part, meets strength requirements, and transforms the traditional mold-based forming process into moldless forming, and from primarily manual installation to primarily digital forming. This improves the manufacturing quality and yield rate, reduces production costs, and shortens the overall manufacturing cycle. Attached Figure Description

[0022] Figure 1 This is a three-dimensional schematic diagram of the structural model of the pointed cone component;

[0023] Figure 2 This is a sectional view of the structural model of the cone-shaped part.

[0024] Figure 3 This is a schematic diagram of the structure of a spiral icosahedron;

[0025] Figure 4 This is a schematic diagram of the spiral wall structure;

[0026] Figure 5 This is a schematic diagram of the supporting structure;

[0027] Figure 6 This is a schematic diagram of the preparation process of chopped carbon fiber composite filaments.

[0028] Wherein: 1-inner wall; 2-outer wall; 3-filler. Detailed Implementation

[0029] Example 1:

[0030] This embodiment of a method for manufacturing a thin-walled composite material part with a pointed conical cavity includes the following steps:

[0031] Step 1: Prepare chopped carbon fiber composite filaments, wherein the chopped carbon fiber composite filaments are composited with short carbon fibers as the reinforcing phase and polyetheretherketone as the resin matrix;

[0032] Step 2: Design the structural model of the cone-shaped part. The structural model of the cone-shaped part includes an inner wall 1, an outer wall 2, and a hollow interlayer disposed between the inner wall 1 and the outer wall 2. The hollow interlayer is filled with a filler 3 through a lattice.

[0033] Step 3: Place the cone-shaped part structure model upside down and add a serrated support structure to the bottom outer side of the cone-shaped part structure model to generate the final process model.

[0034] Step 4: According to the process model, the short-cut carbon fiber composite filament is printed by fused deposition modeling in the following order: printing the outer wall 2, placing the filler 3, and printing the inner wall 1 to form the cone-shaped part.

[0035] Step 5: Remove the support structure on the outside of the cone part, and after grinding the outer wall 2, put the cone part into an oven for heat treatment.

[0036] Furthermore, the thickness of the inner wall 1 is 1-1.2 mm, the thickness of the outer wall 2 is 1-1.2 mm, and the filler 3 is a helical icosahedron.

[0037] Furthermore, the helical icosahedron includes several helical walls, the thickness of which is 0.3-0.5 mm, and the wall spacing between adjacent helical walls is 3-5 mm.

[0038] Furthermore, the diameter of the chopped carbon fiber composite filament is less than or equal to 1.75 mm.

[0039] Furthermore, during the printing process of the cone-shaped part, the printing line width is less than or equal to 0.4 mm, the printing layer thickness is less than or equal to 0.15 mm, and the printing speed is 20-40 mm / s.

[0040] Furthermore, the overlap between printed lines is less than or equal to 10%.

[0041] Furthermore, the spacing between adjacent support structures is less than or equal to 2.5 mm.

[0042] Furthermore, the heat treatment temperature is greater than or equal to 280°C, the heat treatment holding time is greater than or equal to 120 min, and the heating rate during the heat treatment process is less than or equal to 5°C / min.

[0043] Furthermore, such as Figure 6 As shown, short carbon fiber powder and polyether ether ketone powder are dried, then the short carbon fiber powder and polyether ether ketone powder are mixed and dispersed by physical mixing, the mixed powder is dried again, and the dried mixed powder is heated and melted by a twin-screw extruder and extruded to obtain chopped carbon fiber composite filaments.

[0044] Example 2:

[0045] This embodiment discloses a method for manufacturing a thin-walled composite material part with a pointed conical cavity structure, which is further optimized based on Embodiment 1 and includes the following steps:

[0046] Material preparation

[0047] This solution employs fused deposition modeling (FDM), a type of 3D printing process. The principle is as follows: a filament of thermoplastic material is heated and melted in a nozzle, then extruded through a micro-nozzle. After detaching from the nozzle, the thermoplastic material immediately bonds to the previous layer. Once one layer is deposited, the stage lowers by one layer's thickness, and the process continues, depositing the next layer. This process is repeated layer by layer until the desired solid model is formed. Since the chopped carbon fiber composite filament has a diameter of φ1.75mm, it is necessary to prepare the material into filaments for FDM.

[0048] The preparation process of chopped carbon fiber composite filaments mainly includes the following steps:

[0049] 1. Dry the short carbon fiber powder and polyetheretherketone powder separately;

[0050] 2. The dried short carbon fiber powder and polyetheretherketone powder are mixed and dispersed in a certain proportion using a physical method to ensure uniform mixing;

[0051] 3. The powder after blending and dispersing is dried again;

[0052] 4. Use a twin-screw extruder to heat and melt the dried powder, then extrude standard filaments with a specification of φ1.75mm, and use a standard reel for winding.

[0053] Design of the structural model of the pointed cone component:

[0054] Taking into account the overall weight of the part and the manufacturing cycle, and based on previous process experience, such as Figures 1-4 As shown, the thickness of both the outer wall 2 and the inner wall 1 is preferably 1.2 mm. A hollow interlayer is formed between the inner wall 1 and the outer wall 2, and a filler 3 is filled in the hollow interlayer for support. The filler 3 is a helical icosahedron, which includes several helical walls. The thickness t of the helical wall is 0.4 mm, and the wall spacing d between adjacent helical walls is 5 mm.

[0055] Based on the part configuration and the principle of fused deposition modeling, this invention selects an inverted placement method for printing. This method can significantly reduce part deformation and ensure part printing quality; for example... Figure 5 As shown, serrated support structures are added to both sides of the bottom of the part, with a spacing of 2.5mm between adjacent support structures, to generate the process model.

[0056] Parts manufacturing and post-processing:

[0057] Import the process model into the slicing software, set the slicing parameters, generate the printing program code, input the printing program code into the equipment, and start printing the part. The slicing parameters are shown in Table 1:

[0058] Table 1. Printing Slice Parameter Table

[0059]

[0060] After the parts are printed, they are removed from the equipment, and the adhesive film and auxiliary support structures are removed. The surface of the parts is then polished to improve surface quality. To further improve the strength of the parts, they are subjected to heat treatment at 280℃ for 120 minutes with a heating rate of ≤5℃ / min. After heat treatment, the mechanical properties are improved by more than 30%.

[0061] The other parts of this embodiment are the same as those in Embodiment 1, so they will not be described again.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for manufacturing a thin-walled composite material part with a pointed conical cavity structure, characterized in that, Includes the following steps: Step 1: Prepare chopped carbon fiber composite filaments, wherein the chopped carbon fiber composite filaments are composited with short carbon fibers as the reinforcing phase and polyetheretherketone as the resin matrix; Step 2: Design the structural model of the cone-shaped part. The structural model of the cone-shaped part includes an inner wall (1), an outer wall (2), and a hollow interlayer disposed between the inner wall (1) and the outer wall (2). The hollow interlayer is filled with a filler (3) through a lattice. Step 3: Place the cone-shaped part structure model upside down and add a serrated support structure to the bottom outer side of the cone-shaped part structure model to generate the final process model. Step 4: According to the process model, the short-cut carbon fiber composite filament is printed by fused deposition modeling in the order of printing the outer wall (2), placing the filler (3), and printing the inner wall (1). Step 5: Remove the support structure on the outside of the cone part, and after polishing the outer wall (2), put the cone part into the oven for heat treatment.

2. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 1, characterized in that, The thickness of the inner wall (1) is 1-1.2 mm, the thickness of the outer wall (2) is 1-1.2 mm, and the filler (3) is a spiral icosahedron.

3. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 2, characterized in that, The helical icosahedron includes several helical walls, the thickness of which is 0.3-0.5 mm, and the wall spacing between adjacent helical walls is 3-5 mm.

4. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 3, characterized in that, The diameter of the chopped carbon fiber composite filament is less than or equal to 1.75 mm.

5. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 4, characterized in that, During the printing process of the cone-shaped part, the printing line width is less than or equal to 0.4 mm, the printing layer thickness is less than or equal to 0.15 mm, and the printing speed is 20-40 mm / s.

6. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 5, characterized in that, The overlap between printed lines is less than or equal to 10%.

7. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 6, characterized in that, The spacing between adjacent support structures is less than or equal to 2.5 mm.

8. The method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 7, characterized in that, The heat treatment temperature is greater than or equal to 280℃, the heat treatment holding time is greater than or equal to 120min, and the heating rate during the heat treatment process is less than or equal to 5℃ / min.

9. A method for manufacturing a thin-walled composite material part with a pointed conical cavity structure according to claim 8, characterized in that, Short carbon fiber powder and polyether ether ketone powder are dried, and then the short carbon fiber powder and polyether ether ketone powder are mixed and dispersed by physical mixing. The mixed powder is then dried again, and the dried mixed powder is heated and melted by a twin-screw extruder and extruded to obtain chopped carbon fiber composite filaments.

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