A method for manufacturing a seal shell of an alternating hetero-material molding type

Abstract

The application provides a manufacturing method of a sealing shell with a heterogeneous material alternately formed, relates to the technical field of sealing shell manufacturing, and solves the technical problem that the production of the sealing shell with magnetically conductive / non-magnetic alternation is difficult to be efficiently realized through traditional processes. The application comprises the following steps: magnetically conductive / non-magnetic heterogeneous material forming parameter solidification; magnetically conductive / non-magnetic alternation sealing shell model processing; magnetically conductive / non-magnetic alternation sealing shell forming track planning; magnetically conductive / non-magnetic alternation sealing shell forming preparation; magnetically conductive / non-magnetic alternation sealing shell additive / subtractive material forming; and magnetically conductive / non-magnetic alternation sealing shell post-processing. The application can maximize the physical performance and functional characteristics of the material, ensure the dimensional accuracy and surface quality of the product, ensure the good combination between the material layers, improve the overall strength and durability of the sealing shell, and reduce the manufacturing cost, thereby realizing the efficient production of the sealing shell with magnetically conductive / non-magnetic alternation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sealed shell manufacturing, in particular to a sealed shell manufacturing method with heterogeneous material alternating forming. BACKGROUND

[0002] Additive manufacturing technology is a technical hotspot in the field of domestic and foreign processing and manufacturing, and is applied in more and more part manufacturing fields. It improves the design freedom of complex structure products and is applied in functional structure integrated product development, and the comprehensive benefits of forming efficiency and manufacturing cost are continuously optimized. Manufacturing parts through additive technology is the trend of future part processing and manufacturing. Compared with traditional part manufacturing process, additive manufacturing technology solves the problem of difficult forming of complex structure parts, realizes material-structure design-function integration, and is an important way to improve product performance and equipment manufacturing capacity.

[0003] The drive mechanism sealed shell is a part of the reactor coolant system pressure boundary and plays a role in supporting the drive mechanism. At present, the drive mechanism sealed shell is composed of austenitic stainless steel material which is not magnetically conductive. In the conduction of the magnetic circuit, the magnetic resistance of the magnetic circuit of the electromagnetic coil is increased, and the ability of the drive mechanism to lift the load is reduced.

[0004] As disclosed in the patent with publication number CN114141395A, a sealed shell device and a control rod drive mechanism, if the sealed shell structure adopts an alternating distribution structure design of magnetically conductive material and non-magnetic material, the motor working air gap can be significantly reduced, the main magnetic circuit magnetic resistance is reduced, and 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 beneficial 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, the Chinese invention patent document with publication number CN116741415A discloses a control rod drive mechanism and its sealed shell, and a manufacturing method of the sealed shell. A six-time complex welding process is adopted to realize the manufacturing of three cycles of magnetically conductive / non-magnetic alternating products.

[0006] For the related technology in the above, the inventors believe that the problem of realizing the integrated function of magnetically conductive / non-magnetic alternating sealed shell with high efficiency, high quality, high automation and few processes has not been fully studied in China at present. It is difficult to efficiently realize the large-scale alternating of heterogeneous materials on the sealed shell through traditional processes. Therefore, a new type of heterogeneous material alternating distribution structure manufacturing technology is urgently needed. SUMMARY

[0007] The present application provides a sealed shell manufacturing method with heterogeneous material alternating forming, to solve the technical problem that the production of magnetically conductive / non-magnetic alternating sealed shell is difficult to efficiently realize through traditional processes.

[0008] The embodiment of the present application is realized by the following technical solutions:

[0009] A manufacturing method of a heterogeneous material alternately formed sealed shell, comprising the following steps:

[0010] S1: forming parameters of magnetic conductive / non-magnetic conductive heterogeneous material are solidified;

[0011] S2: a magnetic conductive / non-magnetic conductive alternating sealed shell model is processed;

[0012] S3: a magnetic conductive / non-magnetic conductive alternating sealed shell forming track is planned;

[0013] S4: a magnetic conductive / non-magnetic conductive alternating sealed shell is prepared before forming;

[0014] S5: a magnetic conductive / non-magnetic conductive alternating sealed shell is formed by additive manufacturing and subtractive manufacturing;

[0015] S6: a magnetic conductive / non-magnetic conductive alternating sealed shell is processed.

[0016] Preferably, in the step S1, the following specific steps are included: according to the structure of the sealed shell, the structure of the sealed shell is optimized by using simulation software, the optimal arrangement sequence of the magnetic conductive / non-magnetic conductive material of the sealed shell and the corresponding material layer thickness are obtained, and the additive manufacturing process parameters, the subtractive manufacturing process parameters, the additive manufacturing process parameters for guaranteeing the interface dilution rate and the interface performance, and the thermal treatment process parameters for the heterogeneous material homogenization are obtained.

[0017] Preferably, the determination method of the optimal arrangement sequence of the magnetic conductive material and the non-magnetic conductive material in the step S1 can be changing the material layer thickness of the magnetic conductive material and the non-magnetic conductive material, then using finite element analysis software (ANSYS, COMSOL, OPERA) to solve the corresponding lifting force, and the ratio of the magnetic conductive / non-magnetic conductive material corresponding to the maximum lifting force is the optimal arrangement sequence;

[0018] Preferably, as shown in the accompanying drawings, Figure 2 the determination method of the optimal arrangement sequence of the magnetic conductive material and the non-magnetic conductive material in the step S1 can also be first dividing the sealed shell into several parts with equal length according to the length of the required sealed shell, then determining the arrangement sequence and thickness of the material layer of the magnetic conductive material and the non-magnetic conductive material in each part of the sealed shell, and then using the finite element analysis software to solve the corresponding lifting force, and then recording the lifting force value, and then changing the number of parts of the sealed shell, calculating the corresponding lifting force of the sealed shell, until all design schemes are calculated, and finally comparing the size of the lifting force, and the structure of the sealed shell with the maximum lifting force is the optimal arrangement sequence of the magnetic conductive / non-magnetic conductive material;

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

[0020] Preferably, the simulation software uses ANSYS Ansoft Maxwell to perform electromagnetic simulation analysis on the magnetic / non-magnetic materials, and uses static load bearing simulation to optimize the seal shell structure. The single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additive manufacturing process of the magnetic / non-magnetic heterogeneous material is developed, and the specific method is to design and test the single-layer single-channel, single-layer multi-channel, and multi-layer multi-channel laser additive based on the melting points of the magnetic material and the non-magnetic material, and to obtain the best laser additive forming process suitable for the magnetic / non-magnetic material by high-throughput calculation and artificial intelligence algorithm, with the quality of forming efficiency, mechanical properties, internal defects, magnetic properties, and lifting force as the target requirements. The laser three-dimensional scanner is used to measure the corresponding deposition layer width, additive lifting amount, and additive offset amount under the best additive process.

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

[0022] Preferably, in the step S2, the following specific steps are included: using three-dimensional model processing software (such as Creo, NX, CATIA, Solidworks, AutoCAD, etc.) to digitally model the structure of the seal shell, and grouping the digital model of the seal shell according to the best arrangement order of the magnetic / non-magnetic material 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 forming type seal shell is formed by stacking and alternating different materials, in order to make the bonding surface between the layers more reliable, the bonding surface of the current layer of material needs to be subtractively processed before printing the next layer of material. The specific steps are: according to the structure of the material layer and the material properties, using a surface roughness measuring instrument to detect the machining surface precision, and finally determining the best subtractive process of the magnetic / non-magnetic material according to the coupling consideration of the bonding surface precision and the machining 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 trajectories, subtractive trajectories and the initial relative position relationship between the additive robot, the subtractive robot, the work turntable and the sealing shell substrate into the robot programming and simulation design software, obtaining the dual-robot non-interference additive and subtractive alternating trajectories and generating the sealing shell additive and subtractive alternating forming program.

[0025] Preferably, the step S4 includes the following specific steps: introducing the sealing shell additive and subtractive material alternating molding process 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 cylinder;

[0026] During printing, magnetic and non-magnetic materials oxidize when exposed to oxygen at high temperatures, causing changes in the physical and chemical properties of the materials, such as brittleness, discoloration, and the formation of bubbles. Furthermore, the presence of oxygen can affect the adhesion between printed material layers, resulting in a rough surface and reduced interlayer adhesion. All of these factors can reduce the quality and strength of the sealed shell. Therefore, before molding the sealed shell, it is necessary to reduce the oxygen content in the print chamber of the composite additive and subtractive system. In particular, during the additive molding of magnetic and non-magnetic materials, it is necessary to reduce the oxygen content within the additive molding cavity. This can be achieved by replacing the oxygen with an inert gas, such as nitrogen or argon. By introducing nitrogen or argon into the print chamber, the oxygen content within the cavity is reduced to below 100 ppm.

[0027] Preferably, step S5 includes the following specific steps: performing additive and subtractive molding of the sealing shell in an alternating additive and subtractive molding process. Using the aforementioned additive process development method, a magnetic interface additive process for ensuring dilution rate and interface performance is developed on the non-magnetic material after subtraction, and a non-magnetic interface additive process for ensuring interface dilution rate and interface performance is developed on the magnetic material after subtraction.

[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 of the interface between the magnetic material and the non-magnetic material to ensure the interface dilution rate, thereby improving the quality and strength of the bonding surface between the heterogeneous materials. The additive molding process of the magnetic material and the non-magnetic material uses a four-beam high-power additive device to ensure molding efficiency. The subtractive processing adopts high-precision subtractive equipment in the composite additive and subtractive system to ensure dimensional accuracy. The processing accuracy of the subtractive processing is at least 50μm.

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

[0030] Preferably, since the use environment of the sealed shell is relatively harsh, and generally needs to be replaced after 60 years, special heat treatment process is needed for 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, timely homogeneous parameter heat treatment of the heterogeneous material is performed, and the specific heat treatment steps are: the product is kept at 860℃ for 100min, and then cooled to below 600℃ at a cooling rate of <50℃ / h, and then taken out of the furnace for air cooling.

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

[0032] By using the technical solution, the structure of the sealed shell can be optimized through simulation software, the optimal arrangement sequence and layer thickness of the magnetic and non-magnetic materials can be determined, and the physical properties and functional characteristics of the materials can be maximized. By precisely controlling the additive and subtractive process parameters, the combination between the material layers can be ensured, and the overall strength and durability of the sealed shell can be improved. Through electromagnetic simulation analysis, the distribution of the magnetic and non-magnetic materials can be optimized to achieve better electromagnetic shielding effect. Using high-throughput calculation and artificial intelligence algorithm to optimize the forming process can improve production efficiency and reduce material waste. Through laser three-dimensional scanner measurement and computer-aided manufacturing software, the forming track and subtractive track can be precisely controlled to ensure the dimensional accuracy and surface quality of the product. In the forming process, the use of inert gas can reduce the oxygen content, reduce material oxidation, avoid bubbles and discoloration, and improve the interlayer adhesion. The use of low-power ring laser powder feeding equipment at the interface between the magnetic and non-magnetic materials can ensure the interface dilution rate and improve the quality and strength of the interface between the heterogeneous materials. Considering that the sealed shell may be used in harsh environments for up to 60 years, special heat treatment process can increase its service life and ensure long-term stability. This method allows the structure and materials of the sealed shell to be customized according to specific application requirements, providing high design flexibility. By precisely controlling material usage and optimizing the production process, the manufacturing cost can be reduced, and the efficient production of the magnetic / non-magnetic alternately formed sealed shell can be realized.

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

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

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

[0036] 3、The present application reduces manufacturing costs and realizes efficient production of the sealed shell with alternating magnetic / non-magnetic materials. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0038] Figure 1 The manufacturing method flow chart of the manufacturing method of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application;

[0039] Figure 2 The structure diagram of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application;

[0040] Figure 3 The structure diagram of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application;

[0041] Figure 4 The structure diagram of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application;

[0042] Figure 5 The forming step diagram of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application;

[0043] Figure 6 The part physical diagram of the alternating distribution type sealed shell of magnetic / non-magnetic material provided for the embodiment 1 of the present application. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely. The specific conditions in the embodiments are not specified, which are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, which are all conventional products that can be purchased on the market.

[0045] Embodiment 1

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

[0047] A manufacturing method of a heterogeneous material alternately formed sealing shell, comprising the following steps:

[0048] S1: 304LN / 12Cr13 heterogeneous material forming parameter solidification: according to the structure of the sealing shell, the optimal arrangement order of the magnetic conductive / non-magnetic conductive material of the sealing shell and the corresponding material layer thickness are obtained by using simulation software to optimize the structure of the sealing shell. Based on the melting point of 304LN / 12Cr13 material, single-layer single-pass, single-layer multi-pass, and multi-layer multi-pass laser additive manufacturing are designed and tested. Through high-throughput calculation and artificial intelligence algorithm, the optimal laser additive manufacturing process suitable for non-magnetic conductive / magnetic conductive is obtained by taking the forming efficiency and mechanical properties, internal defects, magnetic properties, and lifting force as target requirements. The corresponding deposition layer width, additive lifting amount, and additive offset amount under the optimal additive process are measured by using a laser three-dimensional scanner. The single-layer single-pass, single-layer multi-pass, and multi-layer multi-pass laser additive manufacturing process of 304LN / 12Cr13 heterogeneous material is developed, and the optimal laser additive manufacturing process suitable for 304LN / 12Cr13 is obtained by taking efficiency and quality as target requirements. The optimal laser additive manufacturing process is finally determined as follows: the laser power of the additive robot is 1800W, the scanning speed is 30mm / s, and the powder feeding rate is 8.6g / min during the additive manufacturing of 304LN. The laser power of the additive robot is 2000W, the scanning speed is 30mm / s, and the powder feeding rate is 10.2g / min during the additive manufacturing of 12Cr13. The corresponding deposition layer width, additive lifting amount, and additive offset amount under the optimal additive process are measured by using a laser three-dimensional scanner. The 304LN / 12Cr13 additive manufacturing structure is subjected to subtractive machining under different parameters, the machining surface precision is detected by using a surface roughness measuring instrument, and the optimal subtractive process of 304LN / 12Cr13 is considered by coupling the surface precision and machining efficiency. The optimal subtractive process is finally determined as follows: the cutting speed of the composite additive and subtractive system is 58m / min, and the feed amount is 0.1mm. In order to guarantee the dilution rate and interface performance, the process for guaranteeing the dilution rate and interface performance is divided into two cases according to the different materials of the additive after subtractive. In the first case, the 12Cr13 interface additive process for guaranteeing the dilution rate and interface performance is developed on the 304LN after subtractive, and the specific process is as follows: the laser power of the 304LN additive robot is 600W, the scanning speed is 20mm / s, and the powder feeding rate is 3.0g / min; the laser power of the 12Cr13 is 650W, the scanning speed is 20mm / s, and the powder feeding rate is 3.0g / min;

[0049] The second case is to develop a 304LN interface additive process for guaranteeing interface dilution rate and interface performance on 12Cr13 after subtractive machining. According to the service requirements of 304LN / 12Cr13 materials, a homogenization heat treatment process for double materials is developed, which is to heat the finished sealing shell at 860 DEG C for 100 min, and then cool it in the furnace at a cooling rate of ≤50 DEG C / h to below 600 DEG C and air cool it after taking out of the furnace.

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

[0051] S3: 304LN / 12Cr13 alternating sealing shell forming trajectory planning: in mastercam software, 304LN additive interface parameters, 12Cr13 additive interface parameters, 304LN additive forming parameters and 12Cr13 additive forming parameters in each group cycle are set respectively, 8 forming simulation trajectories are obtained in each group cycle, 2 subtractive trajectories of 304LN / 12Cr13 alternating interface are obtained by using mastercam software. The obtained 8 additive forming trajectories and 2 subtractive trajectories are imported into robotmaster software, the relative position relationship between additive robot, subtractive robot, worktable and product is imported into robotmaster software, so as to establish the relationship between real and virtual robot models, simulate the whole process of robot operation, obtain the non-interference additive and subtractive alternating trajectories of double robots and generate robot program.

[0052] S4: 304LN / 12Cr13 alternating sealing shell forming preparation: import the additive and subtractive alternating forming program of the sealing shell into the composite additive and subtractive system; install the sealing shell base plate into the positioning pin; install the raw material powder of 304LN and 12Cr13 into the corresponding powder feeding cylinder, and introduce gas into the additive forming cavity; when the oxygen content in the additive forming cavity is lower than 100ppm, start the structure forming.

[0053] S5: 304LN / 12Cr13 alternating sealing shell additive and subtractive forming: the sealing shell product forming includes 24 cycles, and the forming operation of each cycle is as follows: Figure 3As shown, the optimal process obtained by the foregoing step S1 is used to sequentially perform 12Cr13 interface addition, 12Cr13 addition forming, 12Cr13 surface subtraction to 5mm, 304LN interface addition, 304LN addition forming, 304LN surface subtraction to 10mm, 12Cr13 interface addition, 12Cr13 addition forming, 12Cr13 surface subtraction to 15mm, 304LN interface addition, 304LN addition forming, and 304LN surface subtraction to 19mm for each group of the sealing shell. Subsequently, the sealing shell substrate is lowered by 19mm, and the above printing step is repeated to start printing of the next group. After 24 groups of cycles are completed, the outer wall and the inner wall of the sealing shell are finished, and the product after finishing is as shown in Figure 5 As shown, the optimal process obtained by the foregoing step S1 is used to sequentially perform 12Cr13 interface addition, 12Cr13 addition forming, 12Cr13 surface subtraction to 5mm, 304LN interface addition, 304LN addition forming, 304LN surface subtraction to 10mm, 12Cr13 interface addition, 12Cr13 addition forming, 12Cr13 surface subtraction to 15mm, 304LN interface addition, 304LN addition forming, and 304LN surface subtraction to 19mm for each group of the sealing shell. Subsequently, the sealing shell substrate is lowered by 19mm, and the above printing step is repeated to start printing of the next group. After 24 groups of cycles are completed, the outer wall and the inner wall of the sealing shell are finished, and the product after finishing is as shown in

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

[0055] The above simulation software analysis, optimization mechanism, model generation, forming trajectory planning and robot program generation are all prior art in the field of 3D printing, and the main invention point of the present application is embodied in the overall manufacturing method.

[0056] The above is only a preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for manufacturing a sealed shell with alternating molding of heterogeneous materials, characterized by: 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 molding trajectory of the magnetic / non-magnetic alternating sealing shell: Based on the grouped digital models obtained in step S2, the molding trajectory and the subtraction trajectory of the magnetic and non-magnetic materials 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 magnetic / non-magnetic alternating sealed shells; In step S1, the following specific steps are included: optimizing the sealed shell structure, determining the optimal arrangement sequence of the magnetic conductive / non-magnetic conductive materials of the sealed shell and the corresponding material layer thickness, as well as the additive process parameters, subtractive process parameters of the sealed 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; 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 non-magnetic conductive material in each sealed shell are determined. Then, the finite element analysis software is used to solve the magnitude of 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 maximum is the optimal arrangement order of the magnetic conductive / non-magnetic conductive material and the corresponding material layer thickness.

2. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 1, 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.

3. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 1, 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 trajectories, subtractive trajectories 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 interference-free alternating additive and subtractive trajectories of the two robots and generating the sealing shell additive and subtractive alternating forming program.

4. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 3, characterized in that: 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 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.

5. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 1, characterized in that: In 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 sequentially performed 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, and the above printing steps are repeated to start printing the next group; After printing is completed, the outer and inner walls of the sealing shell are finely processed.

6. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 5, characterized in that: In step S5, a low-power ring 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.

7. The method for manufacturing a heterogeneous material alternately molded sealed shell according to claim 1, characterized in that: In the step S6, the following specific steps are included: after the sealed shell product is formed and prepared, a heat treatment with homogenized parameters of heterogeneous materials is promptly performed. 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 taking it out of the furnace for air cooling.

8. A sealed housing manufactured by the method for manufacturing a heterogeneous material alternately molded sealed housing according to any one of claims 1 to 7, 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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