Metal powder bed additive manufacturing macrostructure residual deformation control method and system

Abstract

The invention provides a metal powder bed additive manufacturing macrostructure residual deformation control method and system, and the method comprises the steps: 1, obtaining material equivalent inherent strain under different forming process parameters through a metal powder bed melting forming microscale numerical model, establishing a mapping relation between the forming process parameters and the equivalent inherent strain of the material through an approximate model technology; 2, the structure is partitioned, a numerical model is manufactured through a macro-scale metal powder bed additive, macro-structure residual deformation corresponding to regional inherent strain is obtained, an approximate model of partitioned material inherent strain and the maximum residual deformation of the structure is constructed, and the maximum residual deformation of the structure is obtained by combining the mapping relation between forming process parameters and the material inherent strain; the integral structure residual deformation prediction under the multi-partition process parameters is realized; and step 3, carrying out a forming process optimization design of residual deformation minimization to realize the residual deformation control of the macrostructure.

Description

Technical Field

[0001] The present invention relates to the technical field of metal powder bed additive manufacturing, and specifically, to a method and system for controlling macroscopic structure residual deformation in metal powder bed additive manufacturing. Background Art

[0002] In high-end equipment fields such as aerospace, the demand for large-scale precision complex metal components is becoming increasingly urgent. The metal powder bed melting forming process forms complex metal components in a layer-by-layer accumulation manner. Compared with traditional manufacturing technologies, it has the advantages of short production cycle and high material utilization rate, and is becoming an effective way to solve the key technical problems in the aerospace manufacturing field, with broad application prospects.

[0003] However, during the part forming process, the high-energy laser / electron beam and other heat input energies cause local materials to rapidly melt and solidify, and the extremely large temperature gradient generates high residual stresses inside the part, which in turn causes the overall part to undergo thermal deformation, and even causes warping and cracking. For large-scale precision complex components, the influence of residual stresses and deformations is more significant, the forming risk is greater, and the failure cost is higher. Therefore, there is an urgent need to design and develop a method for quickly evaluating and controlling the residual deformation of macroscopic components in metal powder bed additive manufacturing.

[0004] Using numerical simulation methods to simulate the forming process of metal powder bed additive manufacturing parts can predict the structural residual stresses and deformations under different processes, providing a reference basis for the selection of subsequent process parameters. Compared with experimental methods, numerical simulation technology has the advantages of low cost and high efficiency. However, this technology is currently mostly used for the evaluation and prediction of residual stresses and deformations of metal powder bed additive manufacturing parts, lacking a general solution for controlling residual deformations based on the numerical simulation prediction results and proposing relatively better forming processes. Therefore, there is an urgent need to design and develop a method for controlling the residual deformation of macroscopic components in metal powder bed additive manufacturing based on numerical simulation technology, and to achieve the control of structural residual deformation based on process optimization on the basis of quickly evaluating the residual deformation of the formed components. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the purpose of the present invention is to provide a method and system for controlling macroscopic structure residual deformation in metal powder bed additive manufacturing.

[0006] According to the method for controlling macroscopic structure residual deformation in metal powder bed additive manufacturing provided by the present invention, it includes:

[0007] Step 1: Obtain the material equivalent plastic strain under different forming process parameters through a microscopic scale numerical model of metal powder bed melting forming, and establish a mapping relationship between the forming process parameters and the material equivalent plastic strain through approximate model technology;

[0008] Step 2: Partition the structure, use the numerical model of macro-scale metal powder bed additive manufacturing to obtain the macrostructural residual deformation corresponding to the regional inherent strain, construct an approximate model of the partitioned material inherent strain and the maximum residual deformation of the structure, and combine the mapping relationship between the forming process parameters and the material inherent strain to realize the prediction of the overall structural residual deformation under multi-partition process parameters;

[0009] Step 3: Carry out the optimization design of the forming process to minimize the residual deformation and achieve the control of the macrostructural residual deformation.

[0010] Preferably, the said Step 1 includes:

[0011] Step 1.1: Establish a geometric model of the powder layer and the substrate combination, divide the mesh, input the material properties, and set the boundary conditions;

[0012] Step 1.2: Activate the powder layer elements in the forming direction, load the heat source load under the current process parameters, and solve the temperature field until all powder layers are activated;

[0013] Step 1.3: Activate the elements in the order of material forming, read the temperature field solution results in Step 1.2, and solve the stress field until all powder layers are activated;

[0014] Step 1.4: Post-process the calculation results to obtain the average plastic strain of the material as the equivalent inherent strain of the forming process parameters;

[0015] Step 1.5: Repeat Steps 1.1 to 1.4, calculate the equivalent inherent strain under different forming process parameters, and establish an approximate model of the forming process parameters and the material equivalent inherent strain according to the corresponding calculation results.

[0016] Preferably, the said Step 2 includes:

[0017] Step 2.1: Partition the printed macro-component according to its structural characteristics, and the number of partitions is N;

[0018] Step 2.2: Take the x-direction and y-direction inherent strains of each partition as design factors and conduct a 2N-factor experimental design;

[0019] Step 2.3: Establish a structural geometric model, divide the mesh, input the material properties, and apply the boundary conditions;

[0020] Step 2.4: Assign the inherent strain design factor values from the experimental design in Step 2.2 to the corresponding regions of the macrostructural numerical model;

[0021] Step 2.5: Activate the structural elements in sequence according to the height and conduct a mechanical simulation analysis, and carry out the macrostructural residual deformation analysis under the inherent strain;

[0022] Step 2.6: Output the final deformation of the part, where the maximum residual deformation is used as the response of the experimental design;

[0023] Step 2.7: Repeat Steps 2.4 to 2.6 until the calculation of the inherent strain conditions corresponding to all design factor combinations is completed. Based on the numerical simulation results, establish an approximate model with 2N factors as input variables and the maximum residual deformation of the structure as the output variable.

[0024] Preferably, the said Step 3 includes:

[0025] Step 3.1: Take the forming process parameters of N regions as input variables, substitute them into the mapping relationship between the forming process parameters and the material equivalent inherent strain obtained in Step 1, and obtain the x-direction and y-direction inherent strain values of the corresponding regions;

[0026] Step 3.2: Substitute the inherent strain values into the approximate model obtained in Step 2 to calculate the residual deformation of the macroscopic structure;

[0027] Step 3.3: Take the forming process parameters as the optimization variables and the minimization of the residual deformation of the macroscopic structure as the optimization goal. Based on the calculation processes in Steps 3.1 and 3.2, carry out the optimization design of the forming process, select the corresponding optimization algorithm, and iterate until the optimization result converges to obtain the optimized forming process parameters.

[0028] Preferably, the residual deformation control of the cantilever beam structure is realized by optimizing the scanning strategies of different regions. According to the laser process parameters, establish a Gaussian surface heat source model Q, and the expression is:

[0029]

[0030] where x and y are the coordinates of the heat source relative to the center point, A is the laser absorption rate of the powder, P is the laser power, and R is the spot radius.

[0031] According to the metal powder bed additive manufacturing macroscopic structure residual deformation control system provided by the present invention, it includes:

[0032] Module M1: Obtain the material equivalent inherent strain under different forming process parameters through the microscopic scale numerical model of metal powder bed melting forming, and establish the mapping relationship between the forming process parameters and the material equivalent inherent strain through the approximate model technology;

[0033] Module M2: Divide the structure into regions, use the macroscopic scale metal powder bed additive manufacturing numerical model to obtain the macroscopic structure residual deformation corresponding to the regional inherent strain, construct an approximate model of the partition material inherent strain and the maximum residual deformation of the structure, and combine the mapping relationship between the forming process parameters and the material inherent strain to realize the prediction of the overall structure residual deformation under multi-region process parameters;

[0034] Module M3: Carry out the optimization design of the forming process to minimize residual deformation and achieve the control of macroscopic structure residual deformation.

[0035] Preferably, the module M1 includes:

[0036] Module M1.1: Establish a geometric model of the powder layer and the substrate bonding, divide the mesh, input the material properties, and set the boundary conditions;

[0037] Module M1.2: Activate the powder layer units in the forming direction, load the heat source load under the current process parameters, and solve the temperature field until all the powder layers are activated;

[0038] Module M1.3: Activate the units in the material forming sequence, read the temperature field solution results in Module M1.2, and solve the stress field until all the powder layers are activated;

[0039] Module M1.4: Post-process the calculation results to obtain the average plastic strain of the material as the equivalent inherent strain of the forming process parameters;

[0040] Module M1.5: Repeat triggering Modules M1.1 to M1.4, calculate the equivalent inherent strains under different forming process parameters, and establish an approximate model of the forming process parameters and the material equivalent inherent strain according to the corresponding calculation results.

[0041] Preferably, the module M2 includes:

[0042] Module M2.1: Divide the printed macroscopic component according to its structural characteristics, and the number of partitions is N;

[0043] Module M2.2: Take the x-direction and y-direction inherent strains of each partition as design factors and conduct a 2N-factor experimental design;

[0044] Module M2.3: Establish a structural geometric model, divide the mesh, input the material properties, and apply the boundary conditions;

[0045] Module M2.4: Assign the inherent strain design factor values from the experimental design in Module M2.2 to the corresponding regions of the macroscopic structure numerical model;

[0046] Module M2.5: Activate the structural units in sequence according to the height and conduct a mechanical simulation analysis, and carry out an analysis of the macroscopic structure residual deformation under the inherent strain;

[0047] Module M2.6: Output the final deformation of the part, where the maximum residual deformation is used as the response of the experimental design;

[0048] Module M2.7: Repeat triggering Module M2.4 to Module M2.6 until the calculation of the inherent strain conditions corresponding to all combinations of design factors is completed. Based on the numerical simulation results, an approximate model is established with 2N factors as input variables and the maximum residual deformation of the structure as the output variable.

[0049] Preferably, the Module M3 includes:

[0050] Module M3.1: Using the forming process parameters of N regions as input variables, substituting them into the mapping relationship between the forming process parameters and the material equivalent inherent strain obtained by Module M1, to obtain the x-direction and y-direction inherent strain values of the corresponding regions;

[0051] Module M3.2: Substitute the inherent strain values into the approximate model obtained by Module M2 to calculate the residual deformation of the macroscopic structure;

[0052] Module M3.3: Using the forming process parameters as optimization variables and minimizing the residual deformation of the macroscopic structure as the optimization goal, based on the calculation processes in Module M3.1 and Module M3.2, carry out the optimization design of the forming process, select the corresponding optimization algorithm, iterate until the optimization result converges, and obtain the optimized forming process parameters.

[0053] Preferably, the residual deformation control of the cantilever beam structure is realized by optimizing the scanning strategies of different regions. According to the laser process parameters, a Gaussian surface heat source model Q is established, and the expression is:

[0054]

[0055] where x and y are the coordinates of the heat source relative to the center point, A is the laser absorption rate of the powder, P is the laser power, and R is the spot radius.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) Through the multi-scale numerical simulation technology, the layer-by-layer mapping between the forming process parameters - material equivalent inherent strain - macroscopic structure deformation is realized, providing a numerical simulation basis for the macroscopic structure deformation control;

[0058] (2) By establishing an approximate model between the inherent strain and the structural residual deformation, the calculation efficiency of the additive manufacturing macroscopic structure residual deformation is improved, and the optimization efficiency is further improved;

[0059] (3) The calculation method proposed by the present invention can realize the rapid prediction of the residual deformation of large structures under different additive manufacturing forming process parameters. Through the partitioned forming process optimization design with the goal of minimizing the residual deformation, the residual deformation during the printing process of large structures can be controlled to a certain extent. Description of the Drawings

[0060] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non - limiting embodiments read in conjunction with the accompanying drawings:

[0061] Figure 1 is a basic flowchart;

[0062] Figure 2 in (a) and (b) are schematic diagrams of two different laser scanning strategies;

[0063] Figure 3 in (a) and (b) are geometric schematic diagrams of macroscopic structures and their deformation measurement methods;

[0064] Figure 4 is a schematic diagram of a micro - scale finite element model;

[0065] Figure 5 in (a) - (d) are schematic diagrams of AlSi10Mg material properties;

[0066] Figure 6a and Figure 6b are schematic diagrams of the inherent strain calculation region;

[0067] Figure 7 is a schematic diagram of structure partitioning based on structural geometric features;

[0068] Figure 8 is a schematic diagram of a macro - scale finite element model;

[0069] Figure 9 in (a) and (b) are schematic diagrams of the calculated deformation of the macroscopic structure;

[0070] Figure 10 is a comparison chart of the convergence process and results of the scanning strategy process optimization. Detailed implementation manners

[0071] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all fall within the protection scope of the present invention.

[0072] Embodiment 1

[0073] This implementation method realizes the regulation of residual deformation of the macroscopic structure in metal powder bed additive manufacturing by combining multi - scale numerical simulation technology, approximate model technology, and optimization algorithms. As Figure 1 , specifically including:

[0074] Step S1: Based on the microscopic-scale numerical simulation model of metal powder bed additive manufacturing, perform analysis in finite element software to achieve the mapping relationship between the forming process parameters and the material inherent strain;

[0075] Step S2: Based on the macroscopic-scale numerical model, establish a surrogate model for the material inherent strain and the structural residual deformation in different regions. Combining the mapping relationship between the process parameters and the inherent strain, achieve a rapid prediction of the overall structural residual deformation under the partitioned forming process parameters;

[0076] Step S3: Carry out forming process optimization with the goal of minimizing the residual deformation to achieve the control of the macroscopic structural deformation under the optimized forming process parameters.

[0077] The modeling and calculation process of the microscopic-scale numerical simulation model described in Step S1 is specifically carried out as follows:

[0078] Step S1-1: Establish a geometric model of the powder bed and the substrate combination, divide the finite element mesh, input the material properties, and set the heat convection and heat radiation boundary conditions;

[0079] Step S1-2: Kill all powder bed elements, activate the current powder layer according to the material forming sequence, load the heat source load, submit the thermal simulation analysis task, perform analysis in the finite element software, and solve the temperature field. After the current layer scanning calculation is completed, activate the next powder layer and repeat this step until all powder beds are activated;

[0080] Step S1-3: Convert the thermal simulation element type to the structural simulation element type, apply the displacement boundary condition at the bottom of the substrate, and kill all powder bed elements;

[0081] Step S1-4: Activate the powder bed elements according to the material forming sequence, read the temperature field results in Step S1-2, submit the mechanical simulation analysis task, perform analysis in the finite element software, and solve the stress field until all powder layers are activated;

[0082] Step S1-5: Post-process the calculation results to obtain the average plastic strain inside the powder bed as the equivalent inherent strain under this forming process.

[0083] Step S1-6: Repeat Steps S1-2 to S1-5, calculate the equivalent inherent strain under different forming process parameters, and establish an approximate model of the forming process parameters and the material equivalent inherent strain according to the corresponding calculation results.

[0084] The design factor screening process described in Step S2 is specifically carried out as follows:

[0085] Step S2-1: Partition the printed component according to its structural characteristics, and the number of partitions is N;

[0086] Step S2-2: Take the x-direction and y-direction eigenstrain values of each partition as design factors, and the maximum deformation of the structure as the response, and conduct a 2N-factor experimental design.

[0087] Step S2-3: Establish a macroscopic-scale structural model, divide the mesh, input the material properties, and apply fixed boundary conditions at the connection positions with the substrate.

[0088] Step S2-4: Substitute the eigenstrain design factor values from the experimental design in S2-2 into the corresponding regions of the macroscopic structural numerical model.

[0089] Step S2-5: Activate the structural units in sequence according to the height, submit the mechanical simulation analysis task, and conduct analysis in the finite element software to calculate the macroscopic structural residual deformation under eigenstrain.

[0090] Step S2-6: Output the final deformation of the part, where the maximum residual deformation is used as the response of the experimental design.

[0091] Step S2-7: After repeating Steps S2-4 to S2-6 to complete all experimental design conditions, based on the numerical simulation results, establish an approximate model with 2N factors as input variables and the structural characteristic residual deformation as the output variable.

[0092] The macroscopic structural deformation control process under the forming process optimization described in Step S3 is specifically carried out as follows:

[0093] Step S3-1: Take the forming process parameters of N regions as input variables, substitute them into the mapping relationship between the forming process and the material equivalent eigenstrain obtained in Step S1-6, and obtain the x-direction and y-direction eigenstrain values of the corresponding regions.

[0094] Step S3-2: Substitute the 2N eigenstrain values into the approximate model obtained in Step S2-7 to obtain the macroscopic structural residual deformation values.

[0095] Step S3-3: Take the forming process parameters of each region as optimization variables, and the minimization of the macroscopic structural residual deformation as the optimization goal. Based on the calculation processes in S3-1 and S3-2, carry out the forming process optimization design. Considering the calculation scale and solution efficiency of the optimization problem, select a suitable optimization algorithm, and screen out the optimal input variables through a computer program according to the optimization goal, that is, obtain the optimized forming process parameters.

[0096] Embodiment 2

[0097] Taking the laser powder bed fusion (LPBF) forming of an AlSi10Mg cantilever beam structure as an example to illustrate the specific implementation method of the present invention. The finite element model construction and calculation included in this embodiment are carried out in ANSYS software, and the experimental design process, data processing and analysis, and final optimization process are realized in ISIGHT.

[0098] The laser process parameters adopted in this embodiment are shown in Table 1, and the residual deformation of the cantilever beam structure is controlled by optimizing the scanning strategies in different regions. The form of the adopted scanning strategy is as Figure 2 shown. A heat source model is established according to the laser process parameters. In the embodiment of the present invention, a Gaussian surface heat source model Q is used, and the specific expression is:

[0099]

[0100] where x and y are the coordinates of the heat source relative to the center point, A is the laser absorption rate of the powder, P is the laser power, and R is the spot radius.

[0101] The geometric dimensions and displacement measurement methods of the cantilever beam structure used in this embodiment are as Figure 3 shown.

[0102] This embodiment specifically includes the following steps:

[0103] First, build a microscopic-scale numerical simulation model for LPBF forming, select the powder material properties and Gaussian heat source model parameters, and carry out thermo-structural coupling transient response analysis to realize the mapping relationship between the forming process parameters and the material inherent strain. The specific steps are as follows:

[0104] Step 1: Establish the geometric models of the substrate and the powder bed. The size of the powder bed is 0.8 mm × 0.8 mm × 0.15 mm, and the size of the substrate is 1.5 mm × 1.5 mm × 0.5 mm. The schematic diagram of the finite element model is as Figure 4 shown.

[0105] Step 2: Input the thermodynamics properties of the material. The material selected in the embodiment of the present invention is AlSi10Mg, and the specific properties are as Figure 5 shown.

[0106] Step 3: Divide the mesh, set the corresponding heat convection and heat radiation boundary conditions at the positions in contact with the air, and kill all the powder bed elements.

[0107] Step 4: Activate the current powder layer. Taking the time step Δt = R / v as the unit, move the heat source center on the powder bed surface according to the scanning path and load the Gaussian laser heat source Q to solve the temperature field. After the calculation of this layer scanning is completed, activate the next powder layer and repeat this step until the calculation of all powder layers is completed.

[0108] Step 5: Apply displacement boundary conditions to the bottom surface of the substrate and kill all the powder bed elements;

[0109] Step 6: Activate the powder elements in sequence according to the forming order, read the temperature field results in Step 4, and solve the stress field until all the powder layer elements are activated and calculated;

[0110] Step 7: Post-process the calculation results, and obtain the average plastic strain at the center inside the forming material as the equivalent inherent strain under this forming process parameter and scanning strategy. The calculation area is shown in Figure 6. The measurement interval size in this embodiment is 0.4mm×0.4mm×0.1mm.

[0111] Step 8: Change the initial scanning rotation angle and the interlayer rotation angle, and repeat Steps 1 to 7 to calculate the equivalent inherent strain under different forming process parameters. The corresponding relationship between the final obtained scanning strategy process parameters and the inherent strains in the x and y directions is shown in Table 2.

[0112] Then, combined with the relationship between the laser scanning strategy and the inherent strain, realize the rapid prediction of the overall structure residual deformation under different partitioned forming process parameters. The specific steps are as follows:

[0113] Step 9: Partition the cantilever beam structure according to its structural characteristics. The partitioning method in this embodiment is as Figure 7 shown, and the number of partitions is 5;

[0114] Step 10: Take the inherent strain values in the x and y directions of each partition as design factors, and the maximum structural deformation as the response, and use the Optimal Latin Hypercube method to conduct a 10-factor experimental design;

[0115] Step 11: Establish a cantilever beam structure model and divide the mesh, and input the material properties according to Figure 5 the input, and apply fixed boundary conditions at the connection position with the substrate, as Figure 8 shown;

[0116] Step 12: Convert the inherent strain values corresponding to the design factors into the material thermal expansion coefficient and load it on different regions of the structural member model. First, activate the structural member units in sequence according to the forming direction to simulate the structural forming process, and then kill the units at the wire cutting positions in sequence according to the wire cutting direction to simulate the wire cutting process of the cantilever beam support, and output the residual deformation of the part after wire cutting. The final calculation results are as Figure 9 shown.

[0117] Step 13: For the numerical simulation results corresponding to the experimental design parameters, use the Elliptic Basis Function (EBF) neural network method in ISIGHT to establish an approximate model with 10 inherent strains as input variables and the structural warping deformation as the output variable.

[0118] Finally, carry out forming process optimization with the goal of minimizing the structural warping deformation to achieve the control of the macroscopic structure deformation in metal powder bed additive manufacturing. The specific steps are as follows:

[0119] Step 14: Using the scanning initial angles and interlayer rotation angles of the five regions as input parameters, calculate the inherent strain values of the corresponding scanning strategies according to the mapping relationship in Table 2, and calculate the residual deformation of the macroscopic structure based on the elliptic basis function approximation model obtained in Step 13 to achieve rapid prediction of the structural residual deformation under different regional scanning processes.

[0120] Step 15: Using the scanning initial angles and interlayer rotation angles of the five regions as optimization variables and minimizing the residual deformation of the cantilever beam structure as the optimization objective, based on the calculation process in Step 14, adopt the multi-island genetic algorithm in ISIGHT to carry out the optimization design of the scanning strategy. The convergence process of the optimization objective function is as Figure 10 shown, and the finally obtained optimal process parameters are shown in Table 3. Compared with the single scanning processes [initial rotation angle 0°, interlayer rotation angle 0°], [initial rotation angle 0°, interlayer rotation angle 45°], and [initial rotation angle 90°, interlayer rotation angle 0°], the deformation amounts are reduced by 50.9%, 29.7%, and 11.0% respectively.

[0121] Table 1 Laser process parameters

[0122] Process parameters Value Laser absorption rate 0.25 Melting point of AlSi10Mg 870K Ambient temperature 298K Laser power 225W Scanning rate 1200 mm / s Powder layer thickness 30 μm Spot radius 37.5 μm Scanning pitch 100 μm

[0123] Table 2 Mapping relationship between scanning strategy parameters and inherent strain

[0124]

[0125]

[0126] Table 3 Optimal scanning process

[0127] Region number Initial rotation angle (°) Interlayer rotation angle (°) 1 90 0 2 90 0 3 0 90 4 0 90 5 90 0

[0128] Those skilled in the art know that in addition to implementing the systems, devices, and their respective modules provided by the present invention in the form of pure computer-readable program codes, the method steps can be logically programmed to enable the systems, devices, and their respective modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc. to achieve the same program. Therefore, the systems, devices, and their respective modules provided by the present invention can be considered as a kind of hardware component, and the modules included therein for implementing various programs can also be regarded as the structures within the hardware component; the modules for implementing various functions can also be regarded as either software programs for implementing the methods or the structures within the hardware component.

[0129] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for controlling the residual deformation of the macrostructure in metal powder bed additive manufacturing, characterized in that, Including: Step 1: Obtain the equivalent inherent strain of the material under different forming process parameters through a micro-scale numerical model of metal powder bed melting forming, and establish a mapping relationship between the forming process parameters and the equivalent inherent strain of the material through an approximation model technology; Step 2: Divide the structure into zones, use a macro-scale numerical model of metal powder bed additive manufacturing to obtain the macroscopic structural residual deformation corresponding to the zone inherent strain, construct an approximation model between the partition material inherent strain and the maximum residual deformation of the structure, and combine the mapping relationship between the forming process parameters and the material inherent strain to realize the prediction of the overall structural residual deformation under multi-zone process parameters; Step 3: Carry out the optimization design of the forming process to minimize the residual deformation and achieve the control of the macroscopic structural residual deformation.

2. The method for controlling the residual deformation of the macrostructure in metal powder bed additive manufacturing according to claim 1, wherein, The said Step 1 includes: Step 1.1: Establish a geometric model of the powder layer and the substrate bonding, divide the grid, input the material properties, and set the boundary conditions; Step 1.2: Activate the powder layer elements in the forming direction, apply the heat source load under the current process parameters, and solve the temperature field until all powder layers are activated; Step 1.3: Activate the elements in the material forming order, read the temperature field solution results in Step 1.2, and solve the stress field until all powder layers are activated; Step 1.4: Post-process the calculation results to obtain the average plastic strain of the material as the equivalent inherent strain of the forming process parameters; Step 1.5: Repeat Steps 1.1 to 1.4 to calculate the equivalent inherent strain under different forming process parameters, and establish an approximation model between the forming process parameters and the equivalent inherent strain of the material according to the corresponding calculation results.

3. The method for controlling the residual deformation of the macrostructure in metal powder bed additive manufacturing according to claim 2, wherein, The said Step 2 includes: Step 2.1: Divide the printed macroscopic component into zones according to its structural characteristics, and the number of zones is N; Step 2.2: Take the x-direction and y-direction inherent strains of each zone as design factors and conduct a 2N-factor experimental design; Step 2.3: Establish a structural geometric model, divide the grid, input the material properties, and apply boundary conditions; Step 2.4: Assign the inherent strain design factor values in the experimental design in Step 2.2 to the corresponding regions of the macroscopic structural numerical model; Step 2.5: Activate the structural elements in sequence according to the height and conduct a mechanical simulation analysis to carry out the macroscopic structural residual deformation analysis under the inherent strain; Step 2.6: Output the final deformation of the part, and take the maximum residual deformation as the response of the experimental design; Step 2.7: Repeat Steps 2.4 to 2.6 until the inherent strain conditions corresponding to all design factor combinations are calculated. Based on the numerical simulation results, establish an approximation model with 2N factors as input variables and the maximum residual deformation of the structure as the output variable.

4. The method for controlling the macroscopic structural residual deformation in metal powder bed additive manufacturing according to claim 3, wherein The said Step 3 includes: Step 3.1: Take the forming process parameters of N regions as input variables, substitute them into the mapping relationship between the forming process parameters and the equivalent inherent strain of the material obtained in Step 1, and obtain the x-direction and y-direction inherent strain values of the corresponding regions; Step 3.2: Substitute the inherent strain values into the approximation model obtained in Step 2 to calculate the residual deformation of the macroscopic structure. Step 3.3: Taking the forming process parameters as the optimization variables and minimizing the residual deformation of the macroscopic structure as the optimization objective, based on the calculation processes in Step 3.1 and Step 3.2, carry out the optimization design of the forming process, select the corresponding optimization algorithm, iterate until the optimization result converges, and obtain the optimized forming process parameters.

5. The method for controlling the macroscopic structural residual deformation in metal powder bed additive manufacturing according to claim 1, wherein, Control the residual deformation of the cantilever beam structure by optimizing the scanning strategies in different regions. Establish a Gaussian surface heat source model Q according to the laser process parameters, and the expression is: where x and y are the coordinates of the heat source relative to the center point, A is the laser absorption rate of the powder, P is the laser power, and R is the spot radius.

6. A macrostructure residual deformation control system for metal powder bed additive manufacturing, characterized in that, Including: Module M1: Obtain the equivalent plastic strain of the material under different forming process parameters through the microscopic scale numerical model of metal powder bed fusion forming, and establish the mapping relationship between the forming process parameters and the equivalent plastic strain of the material through the approximate model technology; Module M2: Divide the structure into zones, use the macroscopic scale numerical model of metal powder bed additive manufacturing to obtain the macroscopic structure residual deformation corresponding to the zone plastic strain, construct the approximate model of the partition material plastic strain and the maximum residual deformation of the structure, and combine the mapping relationship between the forming process parameters and the material plastic strain to realize the prediction of the overall structure residual deformation under multi-zone process parameters; Module M3: Carry out the optimization design of the forming process to minimize the residual deformation and realize the control of the macroscopic structure residual deformation.

7. The macroscopic structure residual deformation control system for metal powder bed additive manufacturing according to claim 6, characterized in that, The said Module M1 includes: Module M1.1: Establish the geometric model of the powder layer and the substrate combination, divide the mesh, input the material properties, and set the boundary conditions; Module M1.2: Activate the powder layer elements in the forming direction, apply the heat source load under the current process parameters, and solve the temperature field until all powder layers are activated; Module M1.3: Activate the elements in the order of material forming, read the temperature field solution results in Module M1.2, and solve the stress field until all powder layers are activated; Module M1.4: Post-process the calculation results to obtain the average plastic strain of the material as the equivalent plastic strain of the forming process parameters; Module M1.5: Repeat triggering Module M1.1 to Module M1.4, calculate the equivalent plastic strain under different forming process parameters, and establish the approximate model of the forming process parameters and the equivalent plastic strain of the material according to the corresponding calculation results.

8. The macrostructural residual deformation control system for metal powder bed additive manufacturing according to claim 7, characterized in that, The said Module M2 includes: Module M2.1: Divide the printed macroscopic component according to its structural characteristics, and the number of zones is N; Module M2.2: Take the x-direction and y-direction plastic strains of each zone as the design factors, and carry out the 2N factor experimental design; Module M2.3: Establish the geometric model of the structure, divide the mesh, input the material properties, and apply the boundary conditions; Module M2.4: Assign the plastic strain design factor values in the experimental design in Module M2.2 to the corresponding regions of the macroscopic structure numerical model; Module M2.5: Activate the structure elements in sequence according to the height and carry out the mechanical simulation analysis, and carry out the macroscopic structure residual deformation analysis under the plastic strain; Module M2.6: Output the final deformation of the part, and take the maximum residual deformation as the response of the experimental design. Module M2.7: Repeat triggering Module M2.4 to Module M2.6 until the calculation of the inherent strain conditions corresponding to all combinations of design factors is completed. Based on the numerical simulation results, establish an approximate model with 2N factors as input variables and the maximum residual deformation of the structure as the output variable.

9. The macrostructural residual deformation control system for metal powder bed additive manufacturing according to claim 8, characterized in that, The said Module M3 includes: Module M3.1: Take the forming process parameters of N regions as input variables, substitute them into the mapping relationship between the forming process parameters and the material equivalent inherent strain obtained by Module M1, and obtain the x-direction and y-direction inherent strain values of the corresponding regions. Module M3.2: Substitute the inherent strain values into the approximate model obtained by Module M2 to calculate the residual deformation of the macroscopic structure. Module M3.3: Take the forming process parameters as the optimization variables, with the minimization of the macroscopic structure residual deformation as the optimization goal. Based on the calculation processes in Module M3.1 and Module M3.2, carry out the optimization design of the forming process, select the corresponding optimization algorithm, and iterate until the optimization result converges to obtain the optimized forming process parameters.

10. The macrostructural residual deformation control system for metal powder bed additive manufacturing according to claim 6, wherein Control the residual deformation of the cantilever beam structure by optimizing the scanning strategies of different regions. Establish a Gaussian surface heat source model Q according to the laser process parameters. The expression is: Where, x and y are the coordinates of the heat source relative to the center point, A is the laser absorption rate of the powder, P is the laser power, and R is the spot radius.

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