A Hollow Hybrid Network Structure Design and Overall Forming Method

Abstract

This invention discloses a hollow hybrid network structure design and integral forming method, relating to the field of multi-layer hollow structure design and its precision thermoforming technology. While ensuring structural strength, it minimizes structural weight, achieving lightweight design and manufacturing. The overall thickness of the hollow hybrid network structure varies between 0 and 60 mm. A double four-layer structure is used in the 30-60 mm thickness range, a four-layer structure in the 15-30 mm thickness range, and a lattice structure in the thickness below 15 mm. This invention provides high structural strength, and the use of a lattice structure in thinner edge areas ensures certain comprehensive performance while effectively reducing overall weight and material usage, thus achieving the lightweight goal. It fully utilizes the advantages of different core layers to maximize the manufacturing goals of lightweight, high efficiency, and green manufacturing.

Description

Technical Field

[0001] This invention relates to the field of multi-layer hollow structure design and precision thermoforming technology, and particularly to a hollow hybrid network structure design and integral forming method. Background Technology

[0002] Hollow wing-like parts are typically manufactured by welding a skin-skeleton structure. However, this method results in relatively heavy parts, significant welding deformation, and increased risk of defects due to weld seams, leading to a high scrap rate. Superplastic forming / diffusion bonding is a combination of superplastic forming and diffusion bonding. This composite process allows for the fabrication of lightweight, high-strength hollow structures with various structural forms within a similar temperature range. Superplastic forming / diffusion bonding can precisely form complex, multi-layered hollow structures with intricate shapes, without springback. Furthermore, the resulting microstructure is thermomechanically machinable, exhibiting high performance and a long service life.

[0003] Commonly used core layer structures include four-layer structures, corrugated structures, and lattice structures. Among them, the four-layer structure has high compressive strength and simple pretreatment process, and is often used in superplastic forming / diffusion bonding processes. The corrugated structure has a simple pretreatment process, but due to its structural characteristics, its structural strength has obvious anisotropy, and its surface compressive strength is relatively low, making it unsuitable for certain special structures. The lattice structure is one of the most commonly used core layer structures due to its low structural density and good comprehensive performance, but it is mainly suitable for applications with small forming volume and low strength requirements.

[0004] Modern hollow airfoil design is becoming increasingly integrated and specialized. To achieve the combined goals of lightweight and high strength, the specialized design of the core structure and the overall manufacturing of the airfoil are particularly important. For airfoil parts with large thickness gradients, traditional single core structures are insufficient to meet performance requirements. By characterizing and partitioning the entire part, and analyzing the comprehensive performance and formability of different regions, corresponding core structures are selected to create a hollow hybrid network structure design. The introduction of this hybrid core structure presents significant challenges to the overall airfoil forming, necessitating comprehensive process design, including slab shape and thickness design, slab region division and solder resist application design, and superplastic forming / diffusion bonding process control. Post-forming hot isostatic pressing further promotes micropore closure, improves diffusion bonding weld rates, and ensures the stability of diffusion bonding.

[0005] The invention patent with announcement number CN113798791B discloses a manufacturing method for a hollow hybrid structure wing. It employs topology optimization to design the mesh size and distribution of the core plate. The manufacturing steps mainly include hot-pressing pre-forming of the panel, core plate grinding and pickling, and superplastic forming / diffusion bonding after lamination assembly. Its core layer structure is relatively simple, consisting of only a four-layer structure and a lattice structure. It is not suitable for thick hollow wing structures, and the aerodynamic loading process is complex when forming different core layer structures, requiring high precision in loading path design and operation.

[0006] The invention patent with publication number CN110340244B discloses a four-layer structure stepwise superplastic forming-diffusion bonding method, which mainly includes steps such as superplastic forming of the panel, diffusion bonding of the core board, superplastic forming of the core board, combined sealing of the panel and the core board, and diffusion bonding of the panel and the core board. The operation process is relatively complex, with the panel undergoing two thermal cycles and the core board undergoing three thermal cycles. Multiple thermal cycles will reduce the material performance to a certain extent and result in higher economic costs.

[0007] Therefore, in order to ensure the structural strength of the thick hollow wing while minimizing the overall mass, the design of its hybrid core structure and the overall forming method are technical problems that need to be solved by those skilled in the art. Summary of the Invention

[0008] To address the above problems, this invention proposes a hollow hybrid network structure design and integral forming method that minimizes structural weight while ensuring structural strength, thereby achieving lightweight design and manufacturing.

[0009] The technical solution of the present invention is as follows: the overall thickness of the hollow hybrid network structure varies between 0 and 60 mm, a double four-layer structure is selected at the thickness position of 30 to 60 mm, a four-layer structure is selected at the thickness position of 15 to 30 mm, and a dot matrix structure is selected at the thickness position below 15 mm.

[0010] Process according to the following steps:

[0011] Step 1: Cutting the sheet material:

[0012] Laser cutting equipment is used to cut materials according to the design, and the edges are sanded to remove burrs. Two outer panels, two double four-layer panels, two dot matrix panels, and two dot matrix core boards are cut out. Among them, the single four-layer area and the dot matrix area in the double four-layer panels are cut out and removed, and the dot matrix area in the dot matrix core board is cut into a rectangular grid.

[0013] Step 2: Grind, pickle, and spray solder resist on all the boards:

[0014] Use sandpaper to sand the surface of the board, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the oxides on the surface of the board.

[0015] Specifically:

[0016] The inner and outer sides of outer panel 1 and outer panel 2 are all sprayed.

[0017] The outer surfaces of double four-layer panel 1 2 and double four-layer panel 2 7 are all sprayed. The inner surfaces of double four-layer panels 1 2 and double four-layer panel 2 7 are all sprayed except for the ribs and precast blocks in the double four-layer area. The position of air intake b is sprayed.

[0018] Dot matrix panel 1 (3) and dot matrix panel 2 (6) are not painted on the inner and outer sides.

[0019] The outer surfaces of dot matrix core plate 1 4 and dot matrix core plate 2 5 are sprayed in the dot matrix area according to the dot matrix structure requirements; the inner surfaces of dot matrix core plate 1 4 and dot matrix core plate 2 5 are sprayed in the dot matrix area according to the dot matrix structure requirements, and sprayed in the single four-layer area according to the four-layer structure requirements, and sprayed at the position of the air intake d.

[0020] Step 3: Panel sealing and soldering:

[0021] After spraying the solder resist, stack and assemble the two outer panels, seal the edges of the outer panels, and weld the air duct a at the same time during the sealing process;

[0022] Step 4: Check the airtightness after sealing the outer panel;

[0023] Step 5: Outer panel bulging and core board diffusion connection:

[0024] After sealing and welding, the outer panel is placed into mold A. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then, the remaining double four-layer panels, dot matrix panels, and dot matrix core boards are stacked from the outside to the inside to form a multi-layer core board, which is then placed into mold B. The mold cavity of mold B is consistent with the shape of the stacked multi-layer core board. The panels, multi-layer core boards, and molds are stacked together and placed in a heating furnace. The furnace is heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a. The pressure is increased to 2.5-3 MPa at a pressurization rate of 0.01-0.05 MPa / min. After holding the temperature and pressure for a period of time, the pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200°C.

[0025] Step Six: Remove from the oven:

[0026] Remove the bulged outer panel and the diffused multilayer core board from the heating furnace; after the two outer panels are bulged and removed from the furnace, cut open the sealing weld positions around the edges;

[0027] Step 7: Seal and airtightness check of the dot matrix core board:

[0028] Weld the air intake duct d between the two dot matrix core plates and perform an airtightness check.

[0029] Step 8: Apply solder resist.

[0030] Boron nitride solder resist was sprayed onto the outer surfaces of the two double quadruple panels;

[0031] Step 9: Pre-forming of multi-layer core board:

[0032] The multi-layer core board is loaded into mold C. The cavity of mold C is smaller than the shape of the double four-layer area in the structural part to be processed. The multi-layer core board and the mold are placed in a heating furnace and heated to the specified temperature. High-pressure gas is introduced and loaded at a pressurization rate of 0.01-0.02 MPa / min to 2.5-3 MPa. The pressure is maintained for 2-6 hours. After the pressure is maintained, the air pressure in the air inlet of the core board is released and the air pressure in the air inlet d is reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C.

[0033] Step 10: Remove the multilayer core board;

[0034] Step 11: After the core board is formed, cut and pickle it.

[0035] Cut the multi-layer core board after the pre-forming process in step nine to create a cavity area. Use sandpaper to polish the cut area, clean the boron nitride in the cavity area with alcohol, and then clean the cut cavity area and the outer side of the combined core board with a mixed aqueous solution of nitric acid and hydrofluoric acid. Pickle the outer panel formed in step five.

[0036] Step 12: Spot welding of precast blocks:

[0037] Solid prefabricated blocks for connecting the wings and fuselage are made, namely prefabricated block one, prefabricated block two, and prefabricated block three. The shape of prefabricated block two is consistent with the cavity cut out between the two lattice core plates after preforming. Prefabricated blocks one and three are stacked on the upper and lower sides of prefabricated block two, respectively.

[0038] Precast blocks 1 and 3 are spot-welded to the inner sides of outer panel 1 and outer panel 2, respectively. Precast block 2 is welded to the cavity area between matrix core plate 1 and matrix core plate 2.

[0039] Step 13: Sealing and welding of the panel and multilayer core board:

[0040] The multilayer core board is placed between two outer panels, and the edges of the outer panels and the multilayer core board are sealed and welded. At the same time, the air intake ducts a, b, c, and d are welded in the double four-layer area, the single four-layer area, and the dot matrix area, respectively.

[0041] Specifically:

[0042] Two air intakes a are located between outer panel 1 and double four-layer panel 2, and between outer panel 8 and double four-layer panel 7. Air intakes a are welded with air pipes.

[0043] The two air intakes b are double four-layer regional air intakes, located between double four-layer panel 1 2 and dot matrix panel 1 3, and between double four-layer panel 2 7 and core panel 2 6; air intakes b are welded with air pipes.

[0044] The air intake c connects to the matrix area. Corresponding air passages are cut out on both matrix core plate 4 and matrix core plate 5. The air intake c is welded with an air pipe.

[0045] The single four-layer air intake d is a four-layer regional air intake d, which is also located between the matrix core plate 1 4 and the matrix core plate 2 5. The air intake d is welded with an air pipe.

[0046] Step Fourteen: Check the airtightness after overall sealing and welding;

[0047] Step 15: Apply solder resist.

[0048] The outer surface of the outer panel is sprayed with boron nitride solder resist.

[0049] Step Sixteen: Overall Shaping

[0050] The welded panel and multi-layer core board are placed into mold A. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then mold A is placed in a heating furnace and heated to the specified temperature. Argon gas is introduced into the air inlets b, c, and d and pressurized to 2-3 MPa at a pressurization rate of 0.01-0.02 MPa / min. During the expansion process, 0.1 MPa of argon gas is continuously introduced into air inlet a. After maintaining the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200°C.

[0051] Step 17: Remove the item from the oven;

[0052] Step 18: Hot Isostatic Pressing Treatment

[0053] After removing the parts from the previous step, place them in a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the pressure to 100-160 MPa, hold them at the temperature and pressure for 2-6 hours, and then cool them rapidly.

[0054] In step five:

[0055] For titanium alloys, the panel forming and core board diffusion connection temperature is 900-930℃, and the heat preservation and pressure holding time is 2-6 hours;

[0056] For aluminum alloys, the panel forming and core board diffusion connection temperature is 450-530℃, and the heat preservation and pressure holding time is 4-6 hours.

[0057] For magnesium alloys, the panel forming and core board diffusion connection temperature is 460-520℃, and the heat preservation and pressure holding time is 2-4 hours.

[0058] In step eighteen:

[0059] For titanium alloys, the hot isostatic pressing temperature is 800–900℃;

[0060] For aluminum and magnesium alloys, the hot isostatic pressing temperature is 400–500℃.

[0061] The beneficial effects of this invention are as follows:

[0062] I. This invention proposes a double four-layer structure for the thicker parts of hollow wing-like structures, and proposes a design scheme and overall forming method for thick hollow wing-like structures. This avoids the problems of severe local thinning and insufficient forming amount in the forming process of traditional four-layer structures, reduces the risk of breakage, and at the same time improves the structural strength as much as possible while maintaining lightweight.

[0063] Second, this invention provides a customized intermediate core layer structure to address thickness differences at different locations. Specifically, a double four-layer structure is used in the thicker areas to ensure that the area can accommodate a larger forming volume, while a lattice structure is used in the thinner areas to reduce material density while maintaining structural strength. The four-layer structure is used for the transition connection between the two areas, maintaining high structural strength while avoiding structural weight increase.

[0064] Third, this invention combines the characteristics of multiple core layer structures, rationally divides the diffusion connection positions for each layer of slab blank, and uses superplastic forming / diffusion connection process to integrally form a hollow hybrid network structure. Then, the hot isostatic pressing process is used to further improve the welding rate of the wing structure, eliminate internal micro-pores, and improve the overall performance.

[0065] In summary, this invention rationally designs a hollow hybrid network structure based on the characteristics of various core layer structures and manufactures the corresponding structures as a whole. A double four-layer structure is used in the thickest parts of the wing to ensure sufficient forming volume while providing high structural strength. A lattice structure is used in the thinner edge areas to maintain certain comprehensive performance while effectively reducing overall weight and material usage, thus achieving the goal of lightweighting. A four-layer structure is used for transition in the middle thickness areas, making the overall core layer structure harmonious and unified, with a natural transition. By fully utilizing the advantages of different core layers, the manufacturing goals of lightweighting, high efficiency, and green manufacturing are achieved to the greatest extent. Attached Figure Description

[0066] Figure 1 This is a diagram of the hollow hybrid network structure.

[0067] Figure 2 This is a schematic diagram showing the distribution of different regions in the core layer of a hollow hybrid network structure.

[0068] Figure 3 This is a schematic diagram showing the distribution of different regions in the core layer of the hollow hybrid network structure and the cavity after cutting.

[0069] Figure 4 The shapes of each layer of the hollow hybrid network structure are as follows: 1 is outer panel one, 8 is outer panel two; 2 is double four-layer panel one, 7 is double four-layer panel two; 3 is dot matrix panel one, 6 is dot matrix panel two; 4 is dot matrix core panel one, 5 is dot matrix core panel two.

[0070] Figure 5 This is a schematic diagram showing the spraying positions of the solder resist on each layer of the slab.

[0071] Figure 6 This is a schematic diagram of the expansion of the outer panel of the hollow hybrid network structure and the diffusion connection of the double four-layer panel, the lattice panel, and the lattice core board.

[0072] Figure 7 This is a schematic diagram of the pre-formed hollow hybrid network structure double four-layer panel, dot matrix panel, and dot matrix core board.

[0073] Figure 8 This is a schematic diagram of a hollow hybrid network structure formed as a whole in two parts. Detailed Implementation

[0074] To clearly illustrate the technical features of this patent, the following detailed description is provided through specific embodiments and in conjunction with the accompanying drawings.

[0075] The hollow hybrid network structure includes a double four-layer region, a single four-layer region, and a lattice region. Using TC4 titanium alloy, the hollow hybrid network structure requires two outer panels, two double four-layer panels, two lattice panels, and two lattice core plates. The wing-like structure has the following shape... Figure 1 As shown, the internal regions are distributed as follows: Figure 2 , 3 As shown.

[0076] The overall thickness of the hollow hybrid network structure varies between 0 and 60 mm. A double four-layer structure is used in the 30-60 mm thickness position, a four-layer structure is used in the 15-30 mm thickness position, and a dot matrix structure is used in the position below 15 mm thickness.

[0077] Process according to the following steps:

[0078] Step 1: Cutting the sheet material:

[0079] Laser cutting equipment is used to cut materials according to the design, and the edges are sanded to remove burrs. Two outer panels (outer panel 1 and outer panel 2 8), two double four-layer panels (double four-layer panel 1 2 and double four-layer panel 2 7), two dot matrix panels (dot matrix panel 1 3 and dot matrix panel 2 6), and two dot matrix core boards (dot matrix core board 1 4 and dot matrix core board 2 5) are cut out. Among them, the single four-layer area and dot matrix area in the double four-layer panel are cut out, and the dot matrix area in the dot matrix core board is cut into a rectangular grid.

[0080] The shapes of each plate are as follows Figure 4 As shown, where:

[0081] Outer panel 1 and outer panel 2 are 1mm thick.

[0082] Double quadrilayer panel 1 (2) and double quadrilayer panel 2 (7) have a thickness of 0.8mm.

[0083] Dot matrix panel 1 (3) and dot matrix panel 2 (6) are both 0.4mm thick.

[0084] The thickness of dot matrix core board 1 (4) and dot matrix core board 2 (5) is 0.4mm.

[0085] Step 2: Grind, pickle, and spray solder resist on all the boards:

[0086] Use sandpaper to sand the surface of the board, then clean the oxides on the surface of the board with a mixed aqueous solution of nitric acid and hydrofluoric acid. The sprayed areas are as follows: Figure 5 As shown, the black areas represent the locations where solder resist is applied, and the white areas represent the locations where solder resist is not applied.

[0087] Specifically:

[0088] The inner and outer sides of outer panel 1 and outer panel 2 are all sprayed.

[0089] The outer surfaces of double four-layer panel 1 2 and double four-layer panel 2 7 are all sprayed. The inner surfaces of double four-layer panels 1 2 and double four-layer panel 2 7 are all sprayed except for the ribs and precast blocks in the double four-layer area. The position of air intake b is sprayed.

[0090] Dot matrix panel 1 (3) and dot matrix panel 2 (6) are not painted on the inner and outer sides.

[0091] The outer surfaces of dot matrix core plate 1 (4) and dot matrix core plate 2 (5) are sprayed with coating in the dot matrix area according to the dot matrix structure requirements (the ribs in the dot matrix area are sprayed, but the intersection positions are not sprayed); the inner surfaces of dot matrix core plate 1 (4) and dot matrix core plate 2 (5) are sprayed with coating in the dot matrix area according to the dot matrix structure requirements (the ribs in the dot matrix area are sprayed, but the intersection positions are not sprayed), and the single four-layer area is sprayed according to the four-layer structure requirements (the part of the single four-layer area except for the ribs is sprayed), and the position of the air intake d is sprayed (the air intake d connects to the double four-layer area).

[0092] Step 3: Panel sealing and soldering:

[0093] After spraying solder resist, stack and assemble the two outer panels, seal the edges of the outer panels, and weld the air duct a at the same time during the sealing process.

[0094] Step 4: Air tightness check after sealing the outer panel:

[0095] A small amount of gas is introduced between the two outer panels through the air intake a. Soap water is applied to every part of the outer panel after sealing. The absence of soap bubbles indicates good air tightness.

[0096] Step 5: Outer panel bulging and core board diffusion connection:

[0097] After sealing and welding, the outer panel is placed into mold A. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then, the remaining double four-layer panels, dot matrix panels, and dot matrix core boards are stacked from the outside to the inside to form a multi-layer core board, which is then placed into mold B. The mold cavity of mold B is consistent with the shape of the stacked multi-layer core board. The panels, multi-layer core boards, and molds are stacked together and placed in a heating furnace. The furnace is heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a. The pressure is increased to 2.5-3 MPa at a pressurization rate of 0.01-0.05 MPa / min. After holding the temperature and pressure for a period of time, the pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200°C.

[0098] Step 5 completes the air expansion molding of the outer panel (including outer panel 1 and outer panel 2 8), and completes the diffusion connection of the uncoated solder resist positions in the multi-layer core board (including double quadruple panel 1 2, dot matrix panel 1 3, dot matrix core board 1 4, dot matrix core board 2 5, dot matrix panel 2 6, and double quadruple panel 2 7 in sequence).

[0099] Step Six: Remove from the oven:

[0100] Remove the bulged outer panel and the diffused multilayer core board from the heating furnace; after the two outer panels are bulged and removed from the furnace, cut open the sealing weld positions around the edges.

[0101] Step 7: Seal and airtightness check of the dot matrix core board:

[0102] Weld an air intake duct d between two dot matrix core plates (dot matrix core plate 1 4 and dot matrix core plate 2 5). Introduce a small amount of gas through the air intake duct. Apply soapy water to every part of the panel after sealing. The absence of soap bubbles indicates good air tightness.

[0103] Step 8: Apply solder resist.

[0104] Boron nitride solder resist is sprayed onto the outer surfaces of the two double quadruple panels (double quadruple panel 1 2 and double quadruple panel 2 7).

[0105] Step 9: Pre-forming of multi-layer core board:

[0106] The multi-layer core board is loaded into mold C. The cavity of mold C is smaller than the shape of the double four-layer area in the structural part to be processed. The multi-layer core board and the mold are placed in a heating furnace and heated to the specified temperature. High-pressure gas is introduced and loaded at a pressurization rate of 0.01-0.02 MPa / min to 2.5-3 MPa. The pressure is maintained for 2-6 hours. After the pressure is maintained, the air pressure in the air inlet of the core board is released and the air pressure in the air inlet d is reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C.

[0107] Step nine causes the double four-layer region between dot matrix core plate 1 4 and dot matrix core plate 2 5 to expand with air, thereby preforming to half the thickness.

[0108] Step 10: Remove the multilayer core board:

[0109] The multi-layer core board after step nine is removed from the heating furnace as a whole (here, multi-layer core board refers to double four-layer panel 1 2, double four-layer panel 2 7, dot matrix panel 1 3, dot matrix panel 2 6, dot matrix core board 1 4, dot matrix core board 2 5).

[0110] Step 11: After the core board is formed, cut and pickle it.

[0111] After removing the pre-formed multilayer core board from step nine, press it as follows: Figure 3 Cut at the indicated position, cutting into the internal pre-formed cavity area. The cutting position is as follows: Figure 3 As shown; use sandpaper to polish the cut area, use alcohol to clean the boron nitride in the cavity area, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the cut cavity area and the outer side of the composite core board. Pickle the outer panel formed in step five. Since there is a cavity exposed between the matrix core board 1 4 and the matrix core board 2 5, the solder resist on the inner surface of the two in the double four-layer area can be washed away during pickling.

[0112] Step 12: Spot welding of precast blocks:

[0113] Solid prefabricated blocks for connecting the wings and fuselage are made, namely prefabricated block one, prefabricated block two, and prefabricated block three. The shape of prefabricated block two is consistent with the cavity cut out between preformed lattice core plate one 4 and lattice core plate two 5. Prefabricated blocks one and prefabricated block three are stacked on the upper and lower sides of prefabricated block two, respectively, for fixing and connecting outer panel one 1 and outer panel two 8.

[0114] Precast blocks 1 and 3 are spot-welded to the inner sides of outer panel 1 and outer panel 2, respectively. Precast block 2 is welded to the cavity area between matrix core plate 1 and matrix core plate 2.

[0115] Step 13: Sealing and welding of the panel and multilayer core board:

[0116] The multilayer core board is placed between two outer panels, and the edges of the outer panels and the multilayer core board are sealed and welded. At the same time, the air intake ducts a, b, c, and d are welded in the double four-layer area, the single four-layer area, and the dot matrix area, respectively.

[0117] Specifically: Two air intakes a are set between outer panel 1 and double four-layer panel 2, and between outer panel 2 8 and double four-layer panel 2 7. Air intakes a are welded with air pipes and simultaneously enter the two cavities to ensure the shape of outer panel 1 and outer panel 2 8.

[0118] The two air intakes b are double four-layer area air intakes, located between double four-layer panel 1 2 and dot matrix panel 1 3, and between double four-layer panel 2 7 and core panel 2 6. The double four-layer area is spatially divided into upper double four-layer and lower double four-layer. The upper double four-layer air intake is located between double four-layer panel 1 2 and dot matrix panel 1 3, and the lower double four-layer air intake is located between double four-layer panel 2 7 and core panel 2 6. Air intakes b are welded with air pipes and simultaneously enter the two cavities to ensure the shaping of the double four-layer area.

[0119] The air intake duct c connects to the dot matrix area. Corresponding air passages are cut out on both the dot matrix core plate 4 and the dot matrix core plate 5. An air pipe is welded to the air intake duct c for air intake in the dot matrix area.

[0120] The single four-layer air intake d is a four-layer area air intake d, which is also located between the matrix core plate 1 4 and the matrix core plate 2 5. An air pipe is welded to the air intake d for four-layer area air intake.

[0121] Step Fourteen: Air tightness check after overall sealing and welding:

[0122] Introduce a small amount of gas into the air intakes a, b, c, and d. Apply soapy water to every part of the panel after sealing and soldering. If no soap bubbles appear, it indicates good airtightness.

[0123] Step 15: Apply solder resist.

[0124] Boron nitride solder resist is sprayed onto the outer surface of the outer panel (outer panel 1, outer panel 2).

[0125] Step Sixteen: Overall Shaping

[0126] The welded panels (outer panel 1, outer panel 2 8) and multi-layer core boards (double four-layer panel 1 2, double four-layer panel 2 7, dot matrix panel 1 3, dot matrix panel 2 6, dot matrix core board 1 4, dot matrix core board 2 5) are placed into mold A as a whole. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then mold A is placed in a heating furnace and heated to the specified temperature. Argon gas is introduced into the air inlets b, c, and d and pressurized to 2-3 MPa at a pressurization rate of 0.01-0.02 MPa / min. During the expansion process, 0.1 MPa of argon gas is continuously introduced into air inlet a. After maintaining the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200℃.

[0127] Step 17: Retrieve the item from the oven:

[0128] The formed integral part is removed from the heating furnace.

[0129] Step 18: Hot Isostatic Pressing Treatment

[0130] After removing the parts from the previous step, place them in a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the pressure to 100-160 MPa, hold them at the temperature and pressure for 2-6 hours, and then cool them rapidly.

[0131] In step five:

[0132] For titanium alloys, the panel forming and core board diffusion connection temperature is 900-930℃, and the heat preservation and pressure holding time is 2-6 hours;

[0133] For aluminum alloys, the panel forming and core board diffusion connection temperature is 450-530℃, and the heat preservation and pressure holding time is 4-6 hours.

[0134] For magnesium alloys, the panel forming and core board diffusion connection temperature is 460-520℃, and the heat preservation and pressure holding time is 2-4 hours.

[0135] In step eighteen:

[0136] For titanium alloys, the hot isostatic pressing temperature is 800–900℃;

[0137] For aluminum and magnesium alloys, the hot isostatic pressing temperature is 400–500℃.

[0138] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A method for integral forming of a hollow hybrid network structure, characterized in that, The overall thickness of the hollow hybrid network structure varies between 0 and 60 mm. A double four-layer structure is used in the 30-60 mm thickness position, a four-layer structure is used in the 15-30 mm thickness position, and a dot matrix structure is used in the position below 15 mm thickness. Process according to the following steps: Step 1: Cutting the sheet material: Laser cutting equipment is used to cut materials according to the design, and the edges are sanded to remove burrs. Two outer panels, two double four-layer panels, two dot matrix panels, and two dot matrix core boards are cut out. Among them, the single four-layer area and the dot matrix area in the double four-layer panels are cut out and removed, and the dot matrix area in the dot matrix core board is cut into a rectangular grid. Step 2: Grind, pickle, and spray solder resist on all the boards: Use sandpaper to sand the surface of the board, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the oxides on the surface of the board. The inner and outer sides of outer panel 1 (1) and outer panel 2 (8) are all sprayed; The outer surfaces of double four-layer panel one (2) and double four-layer panel two (7) are all sprayed, and the inner surfaces of double four-layer panel one (2) and double four-layer panel two (7) are all sprayed except for the ribs and precast blocks in the double four-layer area. The position of air intake b is sprayed. Dot matrix panel 1 (3) and dot matrix panel 2 (6) are not painted on the inner and outer sides; Spraying is performed on the outer surfaces of dot matrix core plate 1 (4) and dot matrix core plate 2 (5) in the dot matrix area according to the dot matrix structure requirements; spraying is performed on the inner surfaces of dot matrix core plate 1 (4) and dot matrix core plate 2 (5) in the dot matrix area according to the dot matrix structure requirements, and spraying is performed in the single four-layer area according to the four-layer structure requirements, and spraying is performed at the position of the air intake d. Step 3: Panel sealing and soldering: After spraying the solder resist, stack and assemble the two outer panels, seal the edges of the outer panels, and weld the air duct a at the same time during the sealing process; Step 4: Check the airtightness after sealing the outer panel; Step 5: Outer panel bulging and core board diffusion connection: After sealing and welding, the outer panel is placed into mold A. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then, the remaining double four-layer panels, dot matrix panels, and dot matrix core boards are stacked from the outside to the inside to form a multi-layer core board, which is then placed into mold B. The mold cavity of mold B is consistent with the shape of the stacked multi-layer core board. The panels, multi-layer core boards, and molds are stacked together and placed in a heating furnace. The furnace is heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a. The pressure is increased to 2.5-3 MPa at a pressurization rate of 0.01-0.05 MPa / min. After holding the temperature and pressure for a period of time, the pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200°C. Step Six: Remove from the oven: Remove the bulged outer panel and the diffused multilayer core board from the heating furnace; after the two outer panels are bulged and removed from the furnace, cut open the sealing weld positions around the edges; Step 7: Seal and airtightness check of the dot matrix core board: Weld the air intake duct d between the two dot matrix core plates and perform an airtightness check. Step 8: Apply solder resist. Boron nitride solder resist was sprayed onto the outer surfaces of the two double quadruple panels; Step 9: Pre-forming of multi-layer core board: The multi-layer core board is loaded into mold C. The cavity of mold C is smaller than the shape of the double four-layer area in the structural part to be processed. The multi-layer core board and the mold are placed in a heating furnace and heated to the specified temperature. High-pressure gas is introduced and loaded at a pressurization rate of 0.01-0.02 MPa / min to 2.5-3 MPa. The pressure is maintained for 2-6 hours. After the pressure is maintained, the air pressure in the air inlet of the core board is released and the air pressure in the air inlet d is reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C. Step 10: Remove the multilayer core board; Step 11: After the core board is formed, cut and pickle it. Cut the multi-layer core board after the pre-forming process in step nine to create a cavity area. Use sandpaper to polish the cut area, clean the boron nitride in the cavity area with alcohol, and then clean the cut cavity area and the outer side of the combined core board with a mixed aqueous solution of nitric acid and hydrofluoric acid. Pickle the outer panel formed in step five. Step 12: Spot welding of precast blocks: Solid prefabricated blocks for connecting the wings and fuselage are made, namely prefabricated block one, prefabricated block two, and prefabricated block three. The shape of prefabricated block two is consistent with the cavity cut out between the two lattice core plates after preforming. Prefabricated blocks one and three are stacked on the upper and lower sides of prefabricated block two, respectively. Precast blocks 1 and 3 are spot welded to the inner sides of outer panel 1 (1) and outer panel 2 (8), respectively. Precast block 2 is welded to the cavity area between matrix core plate 1 (4) and matrix core plate 2 (5). Step 13: Sealing and welding of the panel and multilayer core board: The multilayer core board is placed between two outer panels, and the edges of the outer panels and the multilayer core board are sealed and welded. At the same time, the air intake ducts a, b, c, and d are welded in the double four-layer area, the single four-layer area, and the dot matrix area, respectively. Two air intakes a are located between outer panel one (1) and double four-layer panel one (2), and between outer panel two (8) and double four-layer panel two (7). Air intakes a are welded with air pipes. The two air intakes b are double four-layer regional air intakes, located between the double four-layer panel one (2) and the dot matrix panel one (3), and between the double four-layer panel two (7) and the dot matrix panel two (6); the air intakes b are welded with air pipes; The intake duct c connects to the dot matrix area. Corresponding air passages are cut out on both the first (4) and the second (5) dot matrix core plate. The intake duct c is welded with an air pipe. The single four-layer air intake d is a four-layer regional air intake, which is also located between the first (4) and the second (5) of the matrix core plate. The air intake d is welded with an air pipe. Step Fourteen: Check the airtightness after overall sealing and welding; Step 15: Apply solder resist. The outer surface of the outer panel is sprayed with boron nitride solder resist. Step Sixteen: Overall Shaping The welded panel and multi-layer core board are placed into mold A. The mold cavity of mold A is consistent with the shape of the structural part to be processed. Then mold A is placed in a heating furnace and heated to the specified temperature. Argon gas is introduced into the air inlets b, c, and d and pressurized to 2-3 MPa at a pressurization rate of 0.01-0.02 MPa / min. During the expansion process, 0.1 MPa of argon gas is continuously introduced into air inlet a. After maintaining the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and mold are cooled to below 200°C. Step 17: Remove the item from the oven; Step 18: Hot Isostatic Pressing Treatment After removing the parts from the previous step, place them in a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the pressure to 100-160 MPa, hold them at the temperature and pressure for 2-6 hours, and then cool them rapidly.

2. The integral forming method of a hollow hybrid network structure according to claim 1, characterized in that, In step five: For titanium alloys, the panel forming and core board diffusion connection temperature is 900-930℃, and the heat preservation and pressure holding time is 2-6 hours; For aluminum alloys, the panel forming and core board diffusion connection temperature is 450-530℃, and the heat preservation and pressure holding time is 4-6 hours. For magnesium alloys, the panel forming and core board diffusion connection temperature is 460-520℃, and the heat preservation and pressure holding time is 2-4 hours.

3. The integral forming method of a hollow hybrid network structure according to claim 1, characterized in that, In step eighteen: For titanium alloys, the hot isostatic pressing temperature is 800–900℃; For aluminum and magnesium alloys, the hot isostatic pressing temperature is 400–500℃.

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