Hollow hybrid network structure design and integral forming method

Abstract

The invention discloses a hollow hybrid network structure design and integral forming method, and relates to the technical field of multi-layer hollow structure design and precise hot forming thereof. The structural weight is reduced as much as possible while the structural strength is guaranteed, and lightweight design and manufacturing are achieved. The overall thickness change of the hollow hybrid network structure ranges from 0 mm to 60 mm, a double-four-layer structure is selected at the position with the thickness ranging from 30 mm to 60 mm, a four-layer structure is selected at the position with the thickness ranging from 15 mm to 30 mm, and a dot matrix structure is selected at the position with the thickness smaller than 15 mm. High structural strength is provided, the area with the thin edge is of the lattice structure, certain comprehensive performance is guaranteed, the overall weight is effectively reduced, few materials are used, and the light weight target is achieved. The advantages of different core layers are fully utilized, and the manufacturing targets of light weight, high efficiency and greenization are achieved to the maximum extent.

Description

Technical Field

[0001] The invention relates to the field of multi-layer hollow structure design and precision thermoforming technology, and in particular to a hollow mixed network structure design and an integral forming method. Background Art

[0002] Hollow wing parts are usually made by welding the skin skeleton structure, but the parts made by this method are relatively heavy and have serious welding deformation. At the same time, the presence of welds increases the risk of defects and the scrap rate is high. The superplastic forming / diffusion bonding process is a combination of the superplastic forming process and the diffusion bonding process. The composite process can prepare lightweight and high-strength hollow structures of various structural forms in a similar temperature range. The superplastic forming / diffusion bonding process can accurately form hollow multi-layer complex structures with complex shapes without springback. At the same time, the formed structure is a thermomechanical processing structure with high performance and long service life.

[0003] Commonly used core layer structures include four-layer structure, corrugated structure and lattice structure. Among them, the four-layer structure has high compressive strength and simple pre-treatment process. It is a structure commonly used in superplastic forming / diffusion bonding process; the corrugated structure has a simple pre-treatment process, but due to its structural characteristics, its structural strength has obvious anisotropy and low surface compressive strength, and it is not applicable in some special structures; the lattice structure is one of the most commonly used core layer structures because of its low structural density and good comprehensive performance, but it is mainly suitable for occasions with small forming volume and low strength requirements.

[0004] Nowadays, the design of hollow wing structures is more comprehensive and specialized. In pursuit of comprehensive goals such as light weight and high strength, the specialized design of the core structure and the overall manufacturing of the wing are particularly important. For wing parts with large thickness gradients, the traditional single core structure is difficult to meet the performance requirements. After the entire part is characterized and partitioned, the corresponding core structure is selected to match the comprehensive performance and forming performance of different regions to form a hollow mixed network structure design. At the same time, the introduction of the mixed core structure brings great challenges to the overall forming of the wing. It is necessary to carry out a full-process process design, including the shape and thickness design of the slab, the division of the slab area of ​​each layer and the design of the solder mask coating, and the control of the superplastic forming / diffusion bonding process. After forming, hot isostatic pressing is performed to further promote the closure of microscopic holes, improve the diffusion bonding welding rate, and ensure the stability of the diffusion bonding.

[0005] The invention patent with announcement number CN113798791B discloses a manufacturing method for hollow hybrid structure rudder wings, which uses topological optimization to design the grid size and distribution of the core plate. The manufacturing steps mainly include hot pressing pre-formed panels, core plate grinding and pickling, superplastic forming / diffusion bonding after lamination assembly, etc. Its core layer structure is relatively simple, including only four-layer structure and lattice structure, which is not suitable for thick hollow wing structures. In addition, the air pressure loading process is complicated when different core layer structures are formed, and the loading path design and operation requirements are high.

[0006] The invention patent with announcement number CN110340244B discloses a four-layer structure step-by-step superplastic forming-diffusion bonding method, which mainly includes superplastic forming of the panel, diffusion bonding of the core plate, superplastic forming of the core plate, combined sealing welding of the panel and the core plate, diffusion bonding of the panel and the core plate, etc. The operation process is relatively complicated, in which the panel undergoes two thermal cycles and the core plate undergoes three thermal cycles. Multiple thermal cycles will reduce the performance of the material to a certain extent, and at the same time cause higher economic costs.

[0007] Therefore, in order to ensure the structural strength of the thick hollow wing while reducing the overall mass as much as possible, the hybrid core layer structure design and the overall forming method thereof are technical problems to be solved by those skilled in the art. Summary of the invention

[0008] In view of the above problems, the present invention proposes a hollow hybrid network structure design and an overall forming method, which can reduce the structural weight as much as possible while ensuring the structural strength, thereby achieving lightweight design and manufacturing.

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

[0010] Follow these steps to process: Step 1: Plate cutting: Laser cutting equipment is used to cut materials according to the design, and the edge burrs are polished with sandpaper to cut out two outer panels, two double four-layer panels, two dot matrix panels, and two dot matrix core panels. Among them, the single four-layer area and the dot matrix area in the double four-layer panel are cut and removed, and the dot matrix area in the dot matrix core panel is cut into a rectangular grid shape; Step 2: Grind, pickle and spray solder resist on all boards: Use sandpaper to polish the surface of the plate, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the oxide on the surface of the plate; Specifically: The inner and outer sides of the outer panel 1 and the outer panel 2 are all sprayed; The outer surfaces of the double four-layer panel 1 2 and the double four-layer panel 2 7 are all sprayed, and the other areas of the double four-layer area of ​​the inner surface of the double four-layer panel 1 2 and the double four-layer panel 2 7 except the ribs and prefabricated blocks are all sprayed, and the position of the air inlet b is sprayed; The inside and outside of dot matrix panel 1 3 and dot matrix panel 2 6 are not sprayed; The outer surfaces of the lattice core plate 1 4 and the lattice core plate 2 5 are sprayed in the lattice area according to the lattice structure requirements; the inner surfaces of the lattice core plate 1 4 and the lattice core plate 2 5 are sprayed in the lattice area according to the lattice structure requirements, and the single four-layer area is sprayed according to the four-layer structure requirements, and the position of the air inlet d is sprayed; Step 3: Panel Sealing: Stack and assemble the two outer panels sprayed with solder resist, seal the edges of the outer panels, and weld the air channel a at the same time; Step 4: Check the air tightness of the outer panel after welding; Step 5: External panel bulging and core panel diffusion connection: The sealed outer panel is loaded into mold A, the mold cavity of mold A is consistent with the shape of the structural part to be processed, and then the remaining double four-layer panels, lattice panels, and lattice core panels are stacked from outside to inside into a multi-layer core panel, and then loaded into mold B, the mold cavity of mold B is consistent with the shape of the stacked multi-layer core panel, and the above panels, multi-layer core panels and molds are stacked as a whole and placed in a heating furnace, heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a, and the pressure is increased to 2.5-3MPa at a pressurization rate of 0.01-0.05MPa / min. After keeping the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1MPa; until the heating furnace and the mold are cooled to below 200°C; Step 6: Take out of the oven: The bulged outer panels and the diffusion-bonded multilayer core panels are taken out of the heating furnace; after the two outer panels are bulged and taken out of the furnace, the sealing weld positions of the edges are cut; Step 7: Sealing welding of the lattice core board and checking of air tightness: Weld the air inlet duct d between the two lattice core plates and check the air tightness; Step 8: Spray solder resist: Spray boron nitride solder resist on the outer surfaces of two double four-layer panels; Step 9: Pre-forming of multi-layer core board: The multi-layer core plate is loaded into the mold C, the mold cavity of the mold C is smaller than the shape of the double four-layer area in the structural part to be processed, the multi-layer core plate and the mold are put into the heating furnace as a whole, heated to the specified temperature, and high-pressure gas is introduced, and the pressure is loaded to 2.5-3MPa at a pressure rate of 0.01-0.02MPa / min, and the pressure is maintained for 2-6 hours; after the pressure maintenance is completed, the air pressure in the core plate air inlet is released, and the air pressure of the air inlet d is reduced to 0.1MPa, until the heating furnace and the mold are cooled to below 200°C; Step 10, take out the multi-layer core board; Step 11: Cut and pickle the core board after forming: Cut the multilayer core board taken out from the pre-forming in step nine to cut out the cavity area, polish the cut part with sandpaper, 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, and pickle the outer panel formed in step five; Step 12: Spot welding of prefabricated blocks: Solid prefabricated blocks for connecting the wing and the fuselage are manufactured, namely, prefabricated block 1, prefabricated block 2, and prefabricated block 3. The shape of prefabricated block 2 is consistent with the cavity cut out between the two lattice core plates after preforming. Prefabricated block 1 and prefabricated block 3 are stacked on the upper and lower sides of prefabricated block 2 respectively. Spot weld the prepared prefabricated block 1 and prefabricated block 3 to the inner sides of the outer panel 1 and the outer panel 2 8 respectively, and weld the prefabricated block 2 to the cavity area between the lattice core plate 1 4 and the lattice core plate 2 5; Step 13: Sealing welding of panel and multi-layer core board: The multi-layer core plate is placed between two outer panels, the edges of the outer panels and the multi-layer core plate are sealed and welded, and the air inlet ducts a, b, c, d are welded in the double four-layer area, the single four-layer area and the dot matrix area respectively; Specifically: Two air inlet ducts a are arranged between the outer panel 1 and the double four-layer panel 2, and between the outer panel 2 8 and the double four-layer panel 2 7, and the air inlet ducts a are welded with air pipes; The two air inlets b are double four-layer regional air inlets, arranged between the double four-layer panel 1 2 and the dot matrix panel 1 3, and between the double four-layer panel 2 7 and the core panel 2 6; the air inlet b is welded with an air pipe; The air inlet c is connected to the lattice area, and corresponding air ducts are cut out on the lattice core plate 1 4 and the lattice core plate 2 5, and the air inlet c is welded with an air pipe; The single four-layer air inlet d is a four-layer regional air inlet, which is also located between the lattice core plate 1 4 and the lattice core plate 2 5, and the air inlet d is welded with an air pipe; Step 14: Check air tightness after overall sealing welding; Step 15: Spray solder resist: Spraying boron nitride solder resist on the outer surface of the outer panel; Step 16: Overall forming: The welded panel and the multi-layer core plate are placed in 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 a specified temperature. Argon gas is introduced into air inlets b, c, and d. The pressure is increased to 2-3 MPa at a pressurization rate of 0.01-0.02 MPa / min. During the bulging process, 0.1 MPa argon gas is continuously introduced into air inlet a. After a period of heat preservation and pressure maintenance, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C. Step 17: Take the pieces out of the oven; Step 18: Hot isostatic pressing: After taking out the parts from the previous step, put them into a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the gas pressure to 100-160MPa, keep them at this temperature and pressure for 2-6 hours, and then cool them quickly.

[0011] In step five: For titanium alloy, the panel forming and core diffusion bonding temperature is 900-930℃, and the heat preservation and pressure holding time is 2-6 hours; For aluminum alloy, the panel forming and core diffusion bonding temperature is 450-530℃, and the heat preservation and pressure holding time is 4-6 hours; For magnesium alloys, the panel forming and core plate diffusion bonding temperature is 460-520°C, and the insulation and pressure holding time is 2-4 hours.

[0012] In step 18: For titanium alloy, the hot isostatic pressing temperature is 800-900℃; For aluminum alloys and magnesium alloys, the hot isostatic pressing temperature is 400-500°C.

[0013] The beneficial effects of the present invention are: 1. The present invention proposes a double four-layer structure for the larger thickness position of the hollow wing structure, and proposes a design scheme and an overall forming method for the large thickness hollow wing structure, so as to avoid the problems of severe local thinning and insufficient forming amount in the forming process of the traditional commonly used four-layer structure, reduce the risk of rupture, and at the same time improve the structural strength as much as possible while maintaining lightweight.

[0014] 2. The present invention customizes the structure of the middle core layer in view of the thickness difference at different positions. Specifically, the double four-layer structure is used in the thicker area to ensure that the area can meet a larger forming amount. The lattice structure is used in the thinner area to reduce the material density while maintaining the structural strength. The four-layer structure is used for the transition connection between the two areas, which not only maintains a high structural strength but also avoids structural weight gain.

[0015] 3. The present invention combines the characteristics of various core layer structures, reasonably divides the diffusion connection positions for each layer of the slab, adopts superplastic forming / diffusion connection process to integrally form a hollow mixed network structure, and then further improves the welding rate of the wing structure through hot isostatic pressing process, eliminates internal microscopic holes, and improves the overall performance.

[0016] In general, the present invention reasonably distributes and designs hollow hybrid network structures according to the characteristics of various core layer structures, and manufactures the corresponding structures as a whole. A double four-layer structure is used at the position with large wing thickness to ensure the forming amount while providing a higher structural strength. A lattice structure is used in the area with thinner edges, which not only ensures certain comprehensive performance, but also effectively reduces the overall weight, uses less material, and achieves the goal of lightweight. A four-layer structure is used for transition in the middle thickness area to make the overall core layer structure coordinated and unified, and transition naturally. Make full use of the advantages of different core layers to achieve the manufacturing goals of lightweight, high efficiency, and green to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the appearance diagram of the hollow hybrid network structure.

[0018] Figure 2 Schematic diagram of the distribution of various regions in the core layer inside the hollow hybrid network structure.

[0019] Figure 3 This is a schematic diagram of the distribution of various areas in the core layer of the hollow hybrid network structure and the cavity after cutting.

[0020] Figure 4 It is the shape of each layer of the hollow hybrid network structure; 1 is the outer panel one, 8 is the outer panel two; 2 is the double four-layer panel one, 7 is the double four-layer panel two; 3 is the lattice panel one, 6 is the lattice panel two; 4 is the lattice core panel one, 5 is the lattice core panel two.

[0021] Figure 5 Schematic diagram of the solder resist spraying position for each layer of the slab.

[0022] Figure 6 It 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, lattice panel, and lattice core panel.

[0023] Figure 7 It is a schematic diagram of the preforming of the hollow hybrid network structure double four-layer panel, lattice panel, and lattice core panel.

[0024] Figure 8 This is a schematic diagram of the overall two-piece forming of the hollow hybrid network structure. DETAILED DESCRIPTION

[0025] In order to clearly illustrate the technical features of this patent, this patent is elaborated in detail below through a specific implementation method and in combination with its accompanying drawings.

[0026] The hollow hybrid network structure includes a double four-layer area, a single four-layer area and a lattice area. 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 panels. The wing structure has a shape like Figure 1 As shown, the internal regions are distributed as follows Figure 2 , 3 shown.

[0027] The overall thickness of the hollow mixed network structure varies between 0 and 60 mm. A double four-layer structure is used at a thickness of 30 to 60 mm, a four-layer structure is used at a thickness of 15 to 30 mm, and a lattice structure is used at a thickness below 15 mm.

[0028] Follow these steps to process: Step 1: Plate cutting: Laser cutting equipment is used to cut materials according to the design, and the edge burrs are polished with sandpaper to cut out two outer panels (outer panel 1, outer panel 2 8), two double four-layer panels (double four-layer panel 1 2, double four-layer panel 2 7), two dot matrix panels (dot matrix panel 1 3, dot matrix panel 2 6), and two dot matrix core panels (dot matrix core panel 1 4, dot matrix core panel 2 5). Among them, the single four-layer area and dot matrix area in the double four-layer panel are cut and removed, and the dot matrix area in the dot matrix core panel is cut into a rectangular grid shape; The shapes of the plates are as follows Figure 4 As shown, where: The thickness of the outer panel 1 and the outer panel 2 is 1 mm. The thickness of double four-layer panel 12 and double four-layer panel 27 is 0.8mm. The thickness of dot matrix panel 1 3 and dot matrix panel 2 6 is 0.4 mm. The thickness of the lattice core board 1 4 and the lattice core board 2 5 is 0.4 mm.

[0029] Step 2: Grind, pickle and spray solder resist on all boards: Use sandpaper to polish the surface of the plate, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the oxide on the surface of the plate. Figure 5 As shown, the black part is the position where the solder resist is sprayed, and the white part is the position where the solder resist is not sprayed; Specifically: The inner and outer sides of the outer panel 1 and the outer panel 2 8 are all sprayed; The outer surfaces of the double four-layer panel 1 2 and the double four-layer panel 2 7 are all sprayed, and the other areas of the double four-layer area of ​​the inner surface of the double four-layer panel 1 2 and the double four-layer panel 2 7 except the ribs and prefabricated blocks are all sprayed, and the position of the air inlet b is sprayed; The inside and outside of dot matrix panel 1 3 and dot matrix panel 2 6 are not sprayed; The outer surfaces of the lattice core plates 1 4 and 2 5 are sprayed in the lattice area according to the lattice structure requirements (the ribs in the lattice area are sprayed, but the intersection positions are not sprayed); the inner surfaces of the lattice core plates 1 4 and 2 5 are sprayed in the lattice area according to the lattice structure requirements (the ribs in the lattice 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 single four-layer area is partially sprayed except the ribs), and the position of the air intake d is sprayed (the air intake duct d is connected to the double four-layer area).

[0030] Step 3: Panel Sealing: The two outer panels sprayed with solder resist are stacked and assembled, and the edges of the outer panels are sealed with solder, and the air channel a is welded at the same time during the sealing process.

[0031] Step 4: Check the air tightness of the outer panel after welding: A small amount of gas is introduced between the two outer panels from the air inlet a, and soapy water is applied to every part of the outer panel parts after sealing and welding. No soap bubbles appear, indicating good air tightness.

[0032] Step 5: External panel bulging and core panel diffusion connection: The sealed outer panel is loaded into mold A, the mold cavity of mold A is consistent with the shape of the structural part to be processed, and then the remaining double four-layer panels, lattice panels, and lattice core panels are stacked from outside to inside into a multi-layer core panel, and then loaded into mold B, the mold cavity of mold B is consistent with the shape of the stacked multi-layer core panel, and the above panels, multi-layer core panels and molds are stacked as a whole and placed in a heating furnace, heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a, and the pressure is increased to 2.5-3MPa at a pressurization rate of 0.01-0.05MPa / min. After keeping the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1MPa; until the heating furnace and the mold are cooled to below 200°C; Step five completes the inflation forming of the outer panels (including outer panel 1 and outer panel 2 8), and completes the diffusion connection of the positions where the solder resist is not applied in the multi-layer core panel (including double four-layer panel 2, lattice panel 3, lattice core panel 4, lattice core panel 2 5, lattice panel 2 6, double four-layer panel 2 7 in sequence).

[0033] Step 6: Take out of the oven: The bulged outer panels and the diffusion-bonded multi-layer core panels are taken out of the heating furnace; after the two outer panels are bulged and taken out of the furnace, the sealing weld positions of the edges are cut.

[0034] Step 7: Sealing welding of the lattice core board and checking of air tightness: Weld the air inlet d between two lattice core plates (lattice core plate 1 4, lattice core plate 2 5), let a small amount of gas in through the air inlet, and apply soapy water to every part of the panel parts after the sealing and welding. No soap bubbles appear, indicating good air tightness.

[0035] Step 8: Spray solder resist: Boron nitride solder resist is sprayed on the outer surfaces of two double four-layer panels (double four-layer panel one 2, double four-layer panel two 7).

[0036] Step 9: Pre-forming of multi-layer core board: The multi-layer core plate is loaded into the mold C, the mold cavity of the mold C is smaller than the shape of the double four-layer area in the structural part to be processed, the multi-layer core plate and the mold are put into the heating furnace as a whole, heated to the specified temperature, and high-pressure gas is introduced, and the pressure is loaded to 2.5-3MPa at a pressure rate of 0.01-0.02MPa / min, and the pressure is maintained for 2-6 hours; after the pressure maintenance is completed, the air pressure in the core plate air inlet is released, and the air pressure of the air inlet d is reduced to 0.1MPa, until the heating furnace and the mold are cooled to below 200°C; Step nine causes the double four-layer area between the lattice core board 1 4 and the lattice core board 2 5 to expand, thereby preforming it to half the thickness.

[0037] Step 10: Take out the multi-layer core board: The multi-layer core board preformed in step nine is taken out of the heating furnace as a whole (the multi-layer core board here refers to double four-layer panel 1 2, double four-layer panel 2 7, lattice panel 1 3, lattice panel 2 6, lattice core board 1 4, lattice core board 2 5).

[0038] Step 11: Cut and pickle the core board after forming: After the pre-formed multi-layer core board is taken out in step 9, Figure 3 Cut at the position shown, cut into the internal pre-formed cavity area, the cutting position is as follows Figure 3 As shown; use sandpaper to grind the cut part, use alcohol to clean the boron nitride in the cavity area, then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the cut cavity area and the outer side of the combined core board, and pickle the outer panel formed in step five. Since there is a cavity exposed between the lattice core board 1 4 and the lattice core board 2 5, the solder resist on the inner surface of the two in the double four-layer area can be washed off during pickling.

[0039] Step 12: Spot welding of prefabricated blocks: Solid prefabricated blocks for connecting the wing and the fuselage are made, namely, prefabricated block 1, prefabricated block 2, and prefabricated block 3. The shape of prefabricated block 2 is consistent with the cavity cut out between the lattice core plate 1 4 and the lattice core plate 2 5 after preforming. Prefabricated block 1 and prefabricated block 3 are stacked on the upper and lower sides of prefabricated block 2, respectively, for fixedly connecting the outer panel 1 and the outer panel 2 8. The prepared prefabricated block 1 and prefabricated block 3 are spot welded to the inner sides of the outer panel 1 and the outer panel 2 8 respectively, and the prefabricated block 2 is welded to the cavity area between the lattice core plate 1 4 and the lattice core plate 2 5 .

[0040] Step 13: Sealing welding of panel and multi-layer core board: The multi-layer core plate is placed between two outer panels, the edges of the outer panels and the multi-layer core plate are sealed and welded, and the air inlet ducts a, b, c, d are welded in the double four-layer area, the single four-layer area and the dot matrix area respectively; Specifically, two air inlets a are arranged between the outer panel 1 and the double four-layer panel 1 2, and between the outer panel 2 8 and the double four-layer panel 2 7. The air inlets a are welded with air pipes and pass into the two cavities at the same time to ensure that the outer panel 1 and the outer panel 2 8 are shaped; The two air inlets b are double four-layer area air inlets, which are arranged between the double four-layer panel 1 2 and the lattice panel 1 3, and between the double four-layer panel 2 7 and the core panel 2 6; the double four-layer area is spatially divided into an upper double four-layer and a lower double four-layer, the upper double four-layer air inlet is located between the double four-layer panel 1 2 and the lattice panel 1 3, and the lower double four-layer air inlet is located between the double four-layer panel 2 7 and the core panel 2 6. The air inlet b is welded with an air pipe and is passed into two cavities at the same time to ensure the finalization of the double four-layer area; The air inlet c is connected to the lattice area, and corresponding air ducts are cut out on the lattice core plate 1 4 and the lattice core plate 2 5. An air pipe is welded to the air inlet c for air intake in the lattice area; The single four-layer air inlet d is a four-layer regional air inlet, which is also located between the lattice core plate 1 4 and the lattice core plate 2 5. An air pipe is welded to the air inlet d for the four-layer regional air intake.

[0041] Step 14: Check air tightness after overall sealing welding: Introduce a small amount of gas into the air inlets a, b, c, and d, and apply soapy water to every part of the panel parts after sealing and welding. No soap bubbles appear, indicating good air tightness.

[0042] Step 15: Spray solder resist: The outer surfaces of the outer panels (outer panel one 1, outer panel two 8) are sprayed with boron nitride solder resist.

[0043] Step 16: Overall forming: The welded panels (outer panel 1, outer panel 2 8) and multi-layer core panels (double four-layer panel 1 2, double four-layer panel 2 7, lattice panel 1 3, lattice panel 2 6, lattice core panel 1 4, lattice core panel 2 5) are placed in 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 a specified temperature. Argon gas is introduced into air inlets b, c, and d, and the pressure is increased to 2 to 3 MPa at a pressurization rate of 0.01 to 0.02 MPa / min. During the bulging process, 0.1 MPa argon gas is continuously introduced into air inlet a. After a period of heat and pressure maintenance, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C.

[0044] Step 17: Take out the product: The formed integral part is taken out from the heating furnace.

[0045] Step 18: Hot isostatic pressing: After taking out the parts from the previous step, put them into a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the gas pressure to 100-160MPa, keep them at this temperature and pressure for 2-6 hours, and then cool them quickly.

[0046] In step five: For titanium alloy, the panel forming and core diffusion bonding temperature is 900-930℃, and the heat preservation and pressure holding time is 2-6 hours; For aluminum alloy, the panel forming and core diffusion bonding temperature is 450-530℃, and the heat preservation and pressure holding time is 4-6 hours; For magnesium alloys, the panel forming and core plate diffusion bonding temperature is 460-520°C, and the insulation and pressure holding time is 2-4 hours.

[0047] In step 18: For titanium alloy, the hot isostatic pressing temperature is 800-900℃; For aluminum alloys and magnesium alloys, the hot isostatic pressing temperature is 400-500°C.

[0048] There are many specific implementation ways of the present invention. The above is only the preferred implementation mode of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

Claims

1. A hollow hybrid network structure, characterized in that: The overall thickness of the hollow mixed network structure varies between 0 and 60 mm. A double four-layer structure is used at a thickness of 30 to 60 mm, a four-layer structure is used at a thickness of 15 to 30 mm, and a lattice structure is used at a thickness below 15 mm.

2. A method for integrally forming a hollow hybrid network structure according to claim 1, characterized in that: Follow these steps to process: Step 1: Plate cutting: Laser cutting equipment is used to cut materials according to the design, and the edge burrs are polished with sandpaper to cut out two outer panels, two double four-layer panels, two dot matrix panels, and two dot matrix core panels. Among them, the single four-layer area and the dot matrix area in the double four-layer panel are cut and removed, and the dot matrix area in the dot matrix core panel is cut into a rectangular grid shape; Step 2: Grind, pickle and spray solder resist on all boards: Use sandpaper to polish the surface of the plate, and then use a mixed aqueous solution of nitric acid and hydrofluoric acid to clean the oxide on the surface of the plate; The inner and outer sides of the outer panel 1 (1) and the outer panel 2 (8) are all spray-coated; The outer surfaces of the double four-layer panel 1 (2) and the double four-layer panel 2 (7) are all spray-painted, and the other areas of the double four-layer area of ​​the inner surface of the double four-layer panel 1 (2) and the double four-layer panel 2 (7) except the ribs and prefabricated blocks are all spray-painted, and the position of the air inlet b is spray-painted; The inside and outside of dot matrix panel 1 (3) and dot matrix panel 2 (6) are not sprayed; The outer surfaces of the lattice core plate 1 (4) and the lattice core plate 2 (5) are sprayed in the lattice area according to the lattice structure requirements; the inner surfaces of the lattice core plate 1 (4) and the lattice core plate 2 (5) are sprayed in the lattice area according to the lattice structure requirements, and the single four-layer area is sprayed according to the four-layer structure requirements, and the position of the air inlet d is sprayed; Step 3: Panel Sealing: Stack and assemble the two outer panels after spraying solder resist, seal the edges of the outer panels, and weld the air channel a at the same time; Step 4: Check the air tightness of the outer panel after welding; Step 5: External panel bulging and core panel diffusion connection: The sealed outer panel is loaded into mold A, the mold cavity of mold A is consistent with the shape of the structural part to be processed, and then the remaining double four-layer panels, lattice panels, and lattice core panels are stacked from outside to inside into a multi-layer core panel, and then loaded into mold B, the mold cavity of mold B is consistent with the shape of the stacked multi-layer core panel, and the above panels, multi-layer core panels and molds are stacked as a whole and placed in a heating furnace, heated to a specified temperature, and argon gas is introduced between the outer panels through the air inlet a, and the pressure is increased to 2.5-3MPa at a pressurization rate of 0.01-0.05MPa / min. After keeping the temperature and pressure for a period of time, the gas pressure is gradually reduced to 0.1MPa; until the heating furnace and the mold are cooled to below 200°C; Step 6: Take out of the oven: The bulged outer panels and the diffusion-bonded multilayer core panels are taken out of the heating furnace; after the two outer panels are bulged and taken out of the furnace, the sealing weld positions of the edges are cut; Step 7: Sealing welding of the lattice core board and checking of air tightness: Weld the air inlet duct d between the two lattice core plates and check the air tightness; Step 8: Spray solder resist: Spray boron nitride solder resist on the outer surfaces of two double four-layer panels; Step 9: Pre-forming of multi-layer core board: The multi-layer core plate is loaded into the mold C, the mold cavity of the mold C is smaller than the shape of the double four-layer area in the structural part to be processed, the multi-layer core plate and the mold are put into the heating furnace as a whole, heated to the specified temperature, and high-pressure gas is introduced, and the pressure is loaded to 2.5-3MPa at a pressure rate of 0.01-0.02MPa / min, and the pressure is maintained for 2-6 hours; after the pressure maintenance is completed, the air pressure in the core plate air inlet is released, and the air pressure of the air inlet d is reduced to 0.1MPa, until the heating furnace and the mold are cooled to below 200°C; Step 10, take out the multi-layer core board; Step 11: Cut and pickle the core board after forming: Cut the multilayer core board taken out from the pre-forming in step nine to cut out the cavity area, polish the cut part with sandpaper, 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, and pickle the outer panel formed in step five; Step 12: Spot welding of prefabricated blocks: Solid prefabricated blocks for connecting the wing and the fuselage are manufactured, namely, prefabricated block 1, prefabricated block 2, and prefabricated block 3. The shape of prefabricated block 2 is consistent with the cavity cut out between the two lattice core plates after preforming. Prefabricated block 1 and prefabricated block 3 are stacked on the upper and lower sides of prefabricated block 2 respectively. Spot-weld the prepared prefabricated block 1 and prefabricated block 3 to the inner sides of the outer panel 1 (1) and the outer panel 2 (8) respectively, and weld the prefabricated block 2 to the cavity area between the lattice core plate 1 (4) and the lattice core plate 2 (5); Step 13: Sealing welding of panel and multi-layer core board: The multi-layer core plate is placed between two outer panels, the edges of the outer panels and the multi-layer core plate are sealed and welded, and the air inlet ducts a, b, c, d are welded in the double four-layer area, the single four-layer area and the dot matrix area respectively; Two air inlet ducts a are arranged between the outer panel 1 (1) and the double four-layer panel 1 (2), and between the outer panel 2 (8) and the double four-layer panel 2 (7), and the air inlet ducts a are welded with air pipes; The two air inlets b are double four-layer regional air inlets, arranged between the double four-layer panel 1 (2) and the dot matrix panel 1 (3), and between the double four-layer panel 2 (7) and the core panel 2 (6); the air inlet b is welded with an air pipe; The air inlet c is connected to the lattice area, and corresponding air ducts are cut out on the lattice core plate 1 (4) and the lattice core plate 2 (5), and the air pipe is welded to the air inlet c; The single four-layer air inlet d is a four-layer regional air inlet, which is also located between the lattice core plate 1 (4) and the lattice core plate 2 (5). The air inlet d is welded with an air pipe; Step 14: Check air tightness after overall sealing welding; Step 15: Spray solder resist: Spraying boron nitride solder resist on the outer surface of the outer panel; Step 16: Overall forming: The welded panel and the multi-layer core plate are placed in 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 a specified temperature. Argon gas is introduced into air inlets b, c, and d. The pressure is increased to 2-3 MPa at a pressurization rate of 0.01-0.02 MPa / min. During the bulging process, 0.1 MPa argon gas is continuously introduced into air inlet a. After a period of heat preservation and pressure maintenance, the gas pressure is gradually reduced to 0.1 MPa until the heating furnace and the mold are cooled to below 200°C. Step 17: Take the pieces out of the oven; Step 18: Hot isostatic pressing: After taking out the parts from the previous step, put them into a hot isostatic pressing furnace, gradually heat them to the specified temperature, raise the gas pressure to 100-160MPa, keep them at this temperature and pressure for 2-6 hours, and then cool them quickly.

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

4. The integral forming method of a hollow hybrid network structure according to claim 2, characterized in that: In step 18: For titanium alloy, the hot isostatic pressing temperature is 800-900℃; For aluminum alloys and magnesium alloys, the hot isostatic pressing temperature is 400-500°C.

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