Heterogeneous material alternate molding type sealing shell manufacturing method

Abstract

The invention provides a manufacturing method of a heterogeneous material alternate molding type sealing shell, relates to the technical field of sealing shell manufacturing, and solves the technical problem that the production of the sealing shell is difficult to efficiently realize through a traditional process when magnetic conduction / non-magnetic conduction is alternated in the prior art. The method comprises the following steps: curing forming parameters of the magnetic-conductive / non-magnetic-conductive heterogeneous material; processing the magnetic-conductive / non-magnetic-conductive alternate sealing shell model; planning a forming track of the magnetic conductive / non-magnetic conductive alternate sealing shell; preparing before forming the magnetic-conductive / non-magnetic-conductive alternate sealing shell; carrying out additive and subtractive forming on the magnetic-conductive / non-magnetic-conductive alternate sealing shell; and post-processing the magnetic-conductive / non-magnetic-conductive alternate sealing shell. According to the invention, the physical properties and functional characteristics of the material can be maximized, and the dimensional precision and surface quality of the product are ensured; good combination between the material layers is ensured, and the overall strength and durability of the sealing shell are improved; and the manufacturing cost is reduced, and efficient production of the sealing shell during magnetic conduction / non-magnetic conduction alternation is realized.

Description

Technical Field

[0001] The invention relates to the technical field of sealing shell manufacturing, and in particular to a method for manufacturing a heterogeneous material alternately molded sealing shell. Background Art

[0002] Additive manufacturing technology is a hot technology in the field of processing and manufacturing at home and abroad. It is applied in more and more parts manufacturing fields. It improves the design freedom of complex structural products and is applied to the development of functional and structural integrated products. At the same time, its forming efficiency and manufacturing cost comprehensive benefits are continuously optimized. Manufacturing parts through additive technology is the trend of future parts processing and manufacturing. Compared with traditional parts manufacturing processes, additive manufacturing technology solves the problem that complex structural parts are difficult to form, realizes material-structure design-function integration, and is an important way to improve product performance and equipment manufacturing capabilities.

[0003] The drive mechanism seal is a component of the reactor coolant system pressure boundary, and plays a role in supporting the drive mechanism. At present, the drive mechanism seal is made of non-magnetic austenitic stainless steel, which increases the magnetic resistance of the electromagnetic coil magnetic circuit during magnetic circuit conduction and reduces the drive mechanism's ability to lift loads.

[0004] For example, a sealed shell device and a control rod drive mechanism proposed in the patent with publication number CN114141395A, if the sealed shell structure adopts a structural design with alternating distribution of magnetic conductive materials and non-magnetic conductive materials, the working air gap of the motor can be significantly reduced, and the magnetic resistance of the main magnetic circuit can be reduced. Under the premise of the same volume, the electromagnetic force output can be significantly improved; in other words, under the premise of the same lifting force, the volume can be significantly reduced, which is conducive to reducing the size of the coil, as well as the weight and cost of the coil, thereby reducing the volume, weight and cost of the sealed shell body.

[0005] In the field of sealed shell manufacturing, a Chinese invention patent document with publication number CN116741415A discloses a control rod drive mechanism and its sealed shell, and a method for manufacturing the sealed shell, which uses six complex welding processes to achieve three cycles of alternating magnetic / non-magnetic products.

[0006] With regard to the above-mentioned related technologies, the inventors believe that the problem of realizing the integrated function of alternating magnetic / non-magnetic sealing shells with high efficiency, high quality, high automation and few processes in China has not been fully studied. It is difficult to efficiently realize the alternation of large quantities of heterogeneous materials on the sealing shell through traditional processes. Therefore, a new manufacturing technology for the alternating distribution structure of heterogeneous materials is urgently needed. Summary of the invention

[0007] The present invention provides a method for manufacturing a heterogeneous material alternately formed sealed shell, so as to solve the technical problem that the production of the existing sealed shell with alternating magnetic conductivity and non-magnetic conductivity is difficult to be efficiently realized through traditional processes.

[0008] The embodiments of the present invention are implemented by the following technical solutions:

[0009] A method for manufacturing a heterogeneous material alternately formed sealing shell comprises the following steps:

[0010] S1: Curing of molding parameters of magnetic / non-magnetic heterogeneous materials;

[0011] S2: Magnetic / non-magnetic alternating sealed shell model processing;

[0012] S3: planning of forming trajectory of magnetic / non-magnetic alternating sealing shell;

[0013] S4: Preparation before molding of magnetic / non-magnetic alternating sealing shell;

[0014] S5: Additive and subtractive forming of magnetic / non-magnetic alternating sealing shell;

[0015] S6: Post-processing of alternating magnetic / non-magnetic sealing shells.

[0016] Preferably, step S1 includes the following specific steps: according to the structure of the sealing shell, using simulation software to optimize the structure of the sealing shell, obtaining the optimal arrangement order of the magnetic / non-magnetic materials of the sealing shell and the corresponding material layer thickness, as well as the additive process parameters of the sealing shell, the subtractive process parameters, the additive process parameters for ensuring the interface dilution rate and interface performance, and the heat treatment process parameters for homogenizing heterogeneous materials.

[0017] Preferably, the method for determining the optimal arrangement order of the magnetic conductive material and the non-magnetic conductive material in step S1 may be to change the thickness of the material layer of the magnetic conductive material and the non-magnetic conductive material, and then use finite element analysis software (any one of ANSYS, COMSOL, and OPERA) to solve the magnitude of the corresponding lifting force, and the ratio of the magnetic conductive material to the non-magnetic conductive material when the lifting force is the largest is the optimal arrangement order;

[0018] Preferably, as attached Figure 2 As shown, the method for determining the optimal arrangement order of the magnetic conductive material and the non-magnetic conductive material in step S1 can also be to first divide the sealed shell into a number of equal lengths according to the required length of the sealed shell, and then determine the arrangement order and thickness of the material layers of the magnetic conductive material and the non-magnetic conductive material in each sealed shell, and then use finite element analysis software to solve the corresponding lifting force, and then record the lifting force value, and then change the number of sealed shells and calculate the lifting force corresponding to the sealed shell until all design schemes are calculated, and finally compare the lifting force. The structure of the sealed shell when the lifting force is the largest is the optimal arrangement order of the magnetic conductive / non-magnetic conductive materials.

[0019] like Figure 3As shown, there is a coil on the outside of the sealed shell and a driving rod on the inside. The driving mechanism adjusts the reaction rate of the reactor by raising and lowering the driving rod. When current in different directions is applied to the coil, the driving rod will be lifted or lowered along the sealed shell. The force that produces this effect is the lifting force. The stronger the magnetic conductivity of the seal and the smaller the air gap, the greater the lifting force of the device. The magnetic conductive material in the heterogeneous material has stronger magnetic conductivity than the sealing shell material in the prior art. 3D printing technology and optimization of the sealing shell structure can make the sealing shell structure more reasonable and reduce the air gap between the sealing shell and the driving rod. Therefore, the structure of the present application can increase the lifting force of the device and improve the performance of the driving mechanism.

[0020] Preferably, the simulation software uses Ansoft Maxwell of ANSYS to perform electromagnetic simulation analysis on magnetic / non-magnetic materials, and the sealed shell structure is optimized by static load simulation. The single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additive manufacturing processes for magnetic / non-magnetic heterogeneous materials are developed. The specific method is to design and test single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additives based on the melting points of magnetic and non-magnetic materials. Through high-throughput computing and artificial intelligence algorithms, the optimal laser additive forming process suitable for magnetic / non-magnetic materials is obtained with the forming efficiency and mechanical properties, internal defects, magnetic properties, lifting force and other qualities as the target requirements, and a laser three-dimensional scanner is used to measure the corresponding deposition layer width, additive lifting amount, additive offset and other forming parameters under the optimal additive process.

[0021] Preferably, in step S1, the additive process parameters and subtractive process parameters include determination of the laser rate, scanning speed, powder feeding rate, cutting speed and feed rate of the composite additive and subtractive system.

[0022] Preferably, step S2 includes the following specific steps: using 3D model processing software (such as Cre0, NX, CATIA, Solidworks, AutoCAD, etc.) to digitally model the structure of the sealing shell, and grouping the digital model of the sealing shell according to the optimal arrangement order of the magnetic / non-magnetic materials obtained in step S1, and determining the total number of groups and the material arrangement and size of each group.

[0023] Since the heterogeneous material alternating molding sealing shell is made of different materials stacked and arranged alternately, in order to make the bonding surface between the layers more reliable, it is necessary to perform subtractive processing on the bonding surface of the current layer of material before printing the next layer of material. The specific steps are: according to the structure of the material layer and the material properties, use a surface roughness measuring instrument to detect the machining surface accuracy, and finally consider the optimal subtractive process of magnetic / non-magnetic materials based on the coupling of surface accuracy and processing efficiency.

[0024] Preferably, step S3 includes the following specific steps: using computer-aided manufacturing software to obtain the corresponding forming trajectories and subtractive trajectories of the magnetic conductive material and the non-magnetic conductive material, importing the forming trajectory, subtractive trajectory and the initial relative position relationship of the additive robot, the subtractive robot, the work turntable and the sealing shell substrate into the robot programming and simulation design software, obtaining the alternating additive and subtractive trajectories without interference of the dual robots and generating the alternating additive and subtractive forming program of the sealing shell.

[0025] Preferably, in the step S4, the following specific steps are included: introducing the sealing shell additive and subtractive material alternating molding program into the composite additive and subtractive material system, fixing the sealing shell base plate, and filling the magnetic conductive material and the non-magnetic conductive material into the corresponding powder feeding tube;

[0026] During printing, magnetic and non-magnetic materials will oxidize when in contact with oxygen at high temperatures, causing changes in the physical and chemical properties of the materials, such as brittleness, discoloration, or bubbles. In addition, the presence of oxygen will affect the bonding between the layers of the printed material, resulting in a rough surface of the printed part and reduced interlayer adhesion. These will reduce the quality and strength of the sealed shell. Therefore, it is necessary to reduce the content of the printing chamber of the composite additive and subtractive system before the sealing shell is formed. In particular, in the process of additive molding of magnetic and non-magnetic materials, it is necessary to reduce the gas content inside the additive molding cavity. The method of reducing the oxygen content inside the cavity is to replace the oxygen with an inert gas, such as nitrogen or argon, and to introduce nitrogen or argon into the printing cavity to make the oxygen content inside the printing cavity less than 100ppm.

[0027] Preferably, in step S5, the following specific steps are included: the sealing shell is subjected to material addition and subtraction in an alternating molding procedure. The aforementioned additive process development method is used to develop a magnetic interface additive process for ensuring the dilution rate and interface performance on the non-magnetic conductive material after material reduction, and a non-magnetic material interface additive process for ensuring the interface dilution rate and interface performance is developed on the magnetic conductive material after material reduction.

[0028] Preferably, in step S5, in order to improve printing efficiency while ensuring product quality, a low-power annular laser powder feeding device is used in the additive process at the interface of the magnetic material and the non-magnetic material to ensure the interface dilution rate so as to improve the quality and strength of the bonding surface between the heterogeneous materials, and a four-beam high-power additive molding process of the magnetic material and the non-magnetic material is used to ensure molding efficiency. Subtractive processing adopts high-precision subtractive equipment in the composite additive and subtractive system to ensure dimensional accuracy, and the processing accuracy of subtractive processing is at least 50μm.

[0029] Preferably, in the step S5, the following steps are also included: using the optimal process parameters and arrangement order of magnetic / non-magnetic materials obtained in step S1, additive, molding and subtractive processing are performed in sequence to obtain a material layer, and a group of sealed shells are obtained by alternately molding different material layers in sequence; then, the sealed shell substrate is lowered so that the height of the printed surface before each group of printing is the same as the initial surface height of the sealed shell substrate, and the above printing steps are repeated to start printing of the next group; after printing is completed, the outer wall and the inner wall of the sealed shell are fine-processed to meet the design specifications.

[0030] Preferably, since the use environment of the sealed shell is relatively harsh and it is generally necessary to ensure that it cannot be replaced for 60 years, it is necessary to perform a special heat treatment process on the printed heterogeneous material alternately formed sealed shell to increase its service life. In the step S6, the following specific steps are included: after the sealed shell product is formed and prepared, the heterogeneous material is promptly subjected to a heat treatment with homogenized parameters. The specific heat treatment steps are: keeping the product at 860°C for 100 minutes, cooling it to below 600°C at a cooling rate of <50°C / h, and then air cooling it out of the furnace.

[0031] Preferably, the magnetic conductive material is martensitic heat-resistant steel, and the non-magnetic conductive material is austenitic stainless steel.

[0032] By adopting this technical solution, the optimal arrangement order and layer thickness of the magnetic and non-magnetic materials can be determined by optimizing the sealing shell structure through simulation software, thereby maximizing the physical properties and functional characteristics of the materials. By precisely controlling the additive and subtractive process parameters, good bonding between material layers can be ensured, and the overall strength and durability of the sealing shell can be improved. Through electromagnetic simulation analysis, the distribution of magnetic and non-magnetic materials can be optimized to achieve better electromagnetic shielding effect. Using high-throughput computing and artificial intelligence algorithms to optimize the molding process can improve production efficiency and reduce material waste. Through laser 3D scanner measurement and computer-aided manufacturing software, the molding trajectory and subtractive trajectory can be precisely controlled to ensure the dimensional accuracy and surface quality of the product. Using inert gas to reduce the oxygen content during the molding process can reduce material oxidation, avoid bubbles and discoloration, and improve interlayer adhesion. Using a low-power ring laser powder feeding device at the interface of magnetic and non-magnetic materials can ensure the interface dilution rate and improve the quality and strength of the bonding surface between heterogeneous materials. Considering that the sealing shell may be used for up to 60 years in harsh environments, a special heat treatment process can increase its service life and ensure long-term stability. This method allows the structure and material of the sealing shell to be customized according to specific application requirements, providing a high degree of design flexibility. By precisely controlling material usage and optimizing the production process, manufacturing costs can be reduced and efficient production of sealing shells can be achieved when alternating between magnetic and non-magnetic conductive materials.

[0033] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects:

[0034] 1. The present invention can maximize the physical properties and functional characteristics of the material and ensure the dimensional accuracy and surface quality of the product;

[0035] 2. The present invention ensures good bonding between material layers and improves the overall strength and durability of the sealed shell;

[0036] 3. The present invention reduces manufacturing costs and realizes efficient production of sealed shells when magnetic conductivity / non-magnetic conductivity are alternating. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 A flow chart of a manufacturing method for a method for manufacturing a sealed shell with alternatingly distributed magnetic conductive / non-magnetic conductive materials provided in Example 1 of the present invention;

[0039] Figure 2 A structural diagram of a sealed shell with alternating distribution of magnetic conductive / non-magnetic conductive materials provided in Example 1 of the present invention;

[0040] Figure 3 A structural diagram of a sealed shell with alternating distribution of magnetic conductive / non-magnetic conductive materials provided in Example 1 of the present invention;

[0041] Figure 4 A structural diagram of a sealed shell with alternating distribution of magnetic conductive / non-magnetic conductive materials provided in Example 1 of the present invention;

[0042] Figure 5 A diagram showing the steps for forming a sealed shell with alternatingly distributed magnetic conductive / non-magnetic conductive materials provided in Example 1 of the present invention;

[0043] Figure 6 A physical picture of the parts of the sealed shell with alternatingly distributed magnetic / non-magnetic materials provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0045] Example 1

[0046] In this embodiment, the magnetic conductive material is 12Cr13 and the non-magnetic conductive material is 304LN;

[0047] A method for manufacturing a heterogeneous material alternately formed sealing shell comprises the following steps:

[0048] S1: Solidification of molding parameters of 304LN / 12Cr13 heterogeneous materials: According to the structure of the sealing shell, the simulation software is used to optimize the structure of the sealing shell, and the optimal arrangement order of the magnetic / non-magnetic materials of the sealing shell and the corresponding material layer thickness are obtained. Based on the melting point of 304LN / 12Cr13 materials, single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additives are designed and tested. Through high-throughput calculations and artificial intelligence algorithms, the optimal laser additive molding processes suitable for non-magnetic / magnetic materials are obtained with molding efficiency and mechanical properties, internal defects, magnetic properties, lifting force and other qualities as target requirements. The corresponding deposition layer width, additive lifting amount, additive offset and other molding parameters under the optimal additive process are measured using a laser 3D scanner; the single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additive manufacturing processes of 304LN / 12Cr13 heterogeneous materials are developed, and the optimal laser additive molding processes suitable for 304LN / 12Cr13 are obtained with efficiency and quality as target requirements. Finally, the optimal laser additive molding process was determined as follows: for 304LN additive molding, the laser power of the additive robot was 1800W, the scanning speed was 30mm / s, and the powder feeding rate was 8.6g / min. For 12Cr13 additive molding, the laser power of the additive robot was 2000W, the scanning speed was 30mm / s, and the powder feeding rate was 10.2g / min. The corresponding forming parameters such as the deposition layer width, additive lifting amount, and additive offset under the optimal additive process were measured using a laser 3D scanner. The 304LN / 12Cr13 additive manufacturing structure was subjected to subtractive processing under different parameters, and the surface roughness measuring instrument was used to detect the machining surface accuracy. The optimal subtractive process of 304LN / 12Cr13 was considered by combining the coupling of surface accuracy and processing efficiency. The optimal subtractive process finally determined is: the cutting speed of the composite additive and subtractive system is 58m / min, and the feed rate is 0.1mm. In order to ensure the dilution rate and interface performance, the process to ensure the dilution rate and interface performance is divided into two cases according to the different materials of the additive after subtraction. The first case is that the 12Cr13 interface additive process for ensuring the dilution rate and interface performance is developed on the 304LN after subtraction. The specific process is: 304LN additive robot laser power 600W scanning speed 20mm / s, powder feeding rate 3.0g / min; 12Cr13: laser power 650W, scanning speed 20mm / s, powder feeding rate 3.0g / min;

[0049] The second case is to develop a 304LN interface additive process on the 12Cr13 after material reduction to ensure the interface dilution rate and interface performance. According to the service requirements of 304LN / 12Cr13 materials, a homogenized heat treatment process for dual materials is developed, which is as follows: the finished sealing shell is kept at 860℃ for 100min, and then cooled to below 600℃ at a cooling rate of ≤50℃ / h, and then air-cooled out of the furnace.

[0050] S2: 304LN / 12Cr13 alternating seal shell model processing: In the creo software, the designed alternating seal shell model (such as Figure 4 As shown), the sealing shell is divided into 24 groups, each of which contains 5mm12Cr13 material layer, 5mm304LN material layer, 5mm12Cr13 material layer, and 4mm304LN material layer.

[0051] S3: 304LN / 12Cr13 alternating sealing shell molding trajectory planning: In Mastercam software, the 304LN additive interface parameters, 12Cr13 additive interface parameters, 304LN additive molding parameters, and 12Cr13 additive molding parameters in each set of cycles are set respectively. Eight molding simulation trajectories are obtained for each set of cycles, and two subtractive trajectories of the 304LN / 12Cr13 alternating interface are obtained using Mastercam software. The obtained 8 additive molding trajectories and 2 subtractive trajectories are imported into Robotmaster software, and the relative position relationship between the additive robot, subtractive robot, work turntable, and product is imported into Robotmaster software, thereby establishing the relationship between the real and virtual robot models, simulating the entire process of robot operation execution, obtaining the alternating trajectory of additive and subtractive materials without interference of the dual robots, and generating the robot program.

[0052] S4: Preparation before 304LN / 12Cr13 alternating sealing shell molding: import the sealing shell additive and subtractive material alternating molding program into the composite additive and subtractive material system; install the sealing shell substrate into the positioning pins; load the raw material powders of 304LN and 12Cr13 into the corresponding powder feeding tubes respectively, and introduce gas into the additive molding cavity; start structural molding when the oxygen content inside the additive molding cavity is lower than 100ppm.

[0053] S5: 304LN / 12Cr13 alternating sealing shell additive and subtractive material forming: The sealing shell product forming includes 24 cycles, and the forming operation of each cycle is: Figure 3As shown, the optimal process obtained in the above step S1 is used to perform 12Cr13 interface additive, 12Cr13 additive molding, 12Cr13 surface reduction to 5mm, 304LN interface additive, 304LN additive molding, 304LN surface reduction to 10mm, 12Cr13 interface additive, 12Cr13 additive molding, 12Cr13 surface reduction to 15mm, 304LN interface additive, 304LN additive molding, 304LN surface reduction to 19mm for each group of sealing shells in turn; then, the sealing shell substrate is lowered by 19mm, and the above printing steps are repeated to start the next group of printing. After completing 24 sets of cycles, the outer and inner walls of the sealing shell are finely processed, and the processed product is as follows Figure 5 As shown. In the additive process of 304LN / 12Cr13 interface, low-power annular laser powder feeding equipment is used to ensure the interface dilution rate. In the additive molding process of 304LN / 12Cr13, four-beam high-power additive equipment is used to ensure molding efficiency. Subtractive processing uses high-precision subtractive equipment in the composite additive and subtractive system to ensure dimensional accuracy, and the processing accuracy is at least 50μm.

[0054] S6: Post-treatment of 304LN / 12Cr13 alternating sealing shell: After the sealing shell product is formed and prepared, the heterogeneous material alternating forming sealing shell is subjected to uniform parameter heat treatment. The specific heat treatment parameters are: 860℃ insulation for 100min, furnace cooling to below 600℃ at ≤50℃ / h, and air cooling before taking out of the furnace.

[0055] The above-mentioned analysis and optimization of the mechanism, generation of the model, planning of the molding trajectory and generation of the robot program through simulation software are all existing technologies in the field of 3D printing. The main inventive point of the present invention is embodied in the overall manufacturing method.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a heterogeneous material alternately formed sealing shell, characterized in that: The steps include: S1: Curing of magnetic / non-magnetic heterogeneous material molding parameters: Determine the optimal arrangement order of magnetic / non-magnetic materials; S2: Processing the model of the alternating magnetic / non-magnetic sealed shell: digitally modeling the structure of the sealed shell, and grouping the digital models of the sealed shell according to the optimal arrangement sequence of the magnetic / non-magnetic materials obtained in step S1; S3: planning the forming trajectory of the magnetic / non-magnetic alternating sealing shell: according to the digital model of the grouping obtained in step S2, the forming trajectory and the material reduction trajectory of the magnetic material and the non-magnetic material are obtained; S4: Preparation before molding of magnetic / non-magnetic alternating sealing shell; S5: Additive and subtractive forming of magnetic / non-magnetic alternating sealing shell; S6: Post-processing of alternating magnetic / non-magnetic sealing shells.

2. The method for manufacturing a heterogeneous material alternately molded sealing shell according to claim 1, characterized in that: In the step S1, the following specific steps are included: optimizing the sealing shell structure, obtaining the optimal arrangement order of the magnetic / non-magnetic materials of the sealing shell and the corresponding material layer thickness, as well as the additive process parameters, subtractive process parameters of the sealing shell, additive process parameters to ensure the interface dilution rate and interface performance, and heat treatment process parameters for homogenizing heterogeneous materials. The additive process parameters and subtractive process parameters include the laser rate, scanning speed, powder feeding rate, cutting speed and feed rate of the composite additive and subtractive system.

3. The method for manufacturing a heterogeneous material alternately molded sealing shell according to claim 2, characterized in that: In step S1, the method for determining the optimal arrangement order of the magnetic conductive material / non-magnetic conductive material is as follows: the sealed shell is divided into several equal-length parts according to the required sealed shell length, and then the arrangement order and thickness of the material layers of the magnetic conductive material and the non-magnetic conductive material in each sealed shell are determined, and then the finite element analysis software is used to solve the corresponding lifting force, and the lifting force value is recorded. The above steps are repeated until the corresponding lifting force of all design schemes is calculated. The structure of the sealed shell when the lifting force is the largest is the optimal arrangement order of the magnetic conductive / non-magnetic conductive material and the corresponding material layer thickness.

4. A method for manufacturing a heterogeneous material alternately formed sealing shell according to any one of claims 1 to 3, characterized in that: In step S2, after the digital model of the sealed shell is grouped, the total number of groups and the material arrangement and size of each group are determined.

5. A method for manufacturing a heterogeneous material alternately formed sealing shell according to any one of claims 1 to 3, characterized in that: In the step S3, the following specific steps are included: using computer-aided manufacturing software to obtain the corresponding forming trajectories and subtractive trajectories of the magnetic conductive material and the non-magnetic conductive material, importing the forming trajectory, subtractive trajectory and the initial relative position relationship of the additive robot, the subtractive robot, the work turntable and the sealing shell substrate into the robot programming and simulation design software, obtaining the double robot non-interference additive and subtractive alternating trajectories and generating the sealing shell additive and subtractive alternating forming program.

6. The method for manufacturing a heterogeneous material alternately molded sealing shell according to claim 5, characterized in that: In the step S4, the following specific steps are included: importing the sealing shell additive and subtractive material alternating molding program into the composite additive and subtractive material system, fixing the sealing shell substrate, filling the magnetic conductive material and the non-magnetic conductive material into the corresponding powder feeding tube, and reducing the oxygen content inside the printing chamber.

7. A method for manufacturing a heterogeneous material alternately formed sealing shell according to any one of claims 1 to 3, characterized in that: In the step S5, the following specific steps are included: using the optimal process parameters and arrangement order of the magnetic conductive / non-magnetic conductive materials obtained in step S1, additive, molding and subtractive processing are performed in sequence to obtain a layer of material, and a group of sealed shells are obtained by alternately molding different material layers in sequence; then, the sealed shell substrate is lowered, and the above printing steps are repeated to start printing of the next group; After printing is completed, the outer and inner walls of the sealing shell are finely processed.

8. The method for manufacturing a heterogeneous material alternately molded sealing shell according to claim 7, characterized in that: In the step S5, a low-power annular laser powder feeding device is used in the additive process of the magnetic / non-magnetic heterogeneous material interface, and a four-beam high-power additive device is used in the additive molding process of the magnetic / non-magnetic heterogeneous material. The processing accuracy of the subtractive processing is at least 50μm.

9. A method for manufacturing a heterogeneous material alternately formed sealing shell according to any one of claims 1 to 3, characterized in that: In the step S6, the following specific steps are included: after the sealing shell product is formed and prepared, the heterogeneous material is promptly subjected to parameter homogenization heat treatment, and the specific heat treatment steps are: the product is kept at 860°C for 100 minutes, and is furnace cooled to below 600°C at a cooling rate of <50°C / h, and then air-cooled out of the furnace.

10. A sealed shell manufactured by the method for manufacturing a sealed shell of alternately formed heterogeneous materials according to any one of claims 1 to 9, characterized in that: The magnetic conductive material is martensitic heat-resistant steel, and the non-magnetic conductive material is austenitic stainless steel.

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