Laser powder bed melting forming method for ultra-large thin-wall complex structural part

Abstract

The invention discloses a laser powder bed melting forming method for an ultra-large thin-wall complex structural part, and belongs to the technical field of alloy structural part additive manufacturing. The technical problem that an existing ultra-large thin-wall complex structural part deforms due to thermal stress in the laser powder bed melting forming process is solved. The forming method comprises the following steps: step 1, analogue simulation and pre-deformation; 2, first-round laser powder bed melting additive manufacturing is carried out; 3, first-round post-treatment is carried out; step 4, performing three-dimensional scanning on the solid blank; step 5, carrying out object iteration model processing; 6, laser powder bed melting additive manufacturing is carried out; and step 7, performing iteration post-processing. According to the method, a closed-loop control mechanism of'prediction-compensation-verification-iterative adjustment 'is established, so that the problem of deformation of the ultra-large thin-wall complex structural part caused by thermal stress in the laser powder bed melting forming process is solved.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing of alloy structural parts, and more particularly to a laser powder bed melting forming method for ultra-large thin-walled complex structural parts. Background Technology

[0002] In existing technologies, laser powder bed fusion (L-PBF) technology faces significant technical challenges when molding ultra-large, thin-walled, complex structural parts. As a thermal processing method, L-PBF inevitably generates substantial thermal stress during the printing process and subsequent stress relief heat treatment, leading to significant deformation of the parts.

[0003] As product height and size increase, and structural complexity continues to rise, this deformation problem becomes increasingly severe, making it difficult to effectively guarantee the surface accuracy of the molded product. To compensate for the deformation problem, large-area overlay machining is usually required, which is extremely disadvantageous for those difficult-to-machine parts and significantly increases the time and cost required for machining, thereby weakening the advantages of L-PBF technology compared to traditional casting processes.

[0004] Therefore, how to effectively control the deformation of ultra-large thin-walled complex structural parts during the L-PBF forming process and ensure the surface accuracy is an urgent technical problem that needs to be solved. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a laser powder bed melting forming method for ultra-large thin-walled complex structural parts, in order to solve the deformation problem caused by thermal stress in the laser powder bed melting forming process of ultra-large thin-walled complex structural parts.

[0006] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a laser powder bed melting forming method for ultra-large thin-walled complex structural parts, comprising the following steps: Step 1: Simulation + Pre-deformation; First, a blank model is established, and then supports are added to the blank model. The laser powder bed melting process is simulated using Simufact Additive software to predict the deformation of the blank model and obtain the simulation results of the blank model. Based on the simulation results, the blank model is pre-deformed using Simufact Additive software, and the pre-deformation ratio is set to 0.6~1. Step 2: First round of laser powder bed fusion additive manufacturing; Step 21: Convert the format of the blank model after pre-deformation to STL format, and re-print the blank model and add supports in Magics software. Step 22: After the support is added, use Magics software and the device's built-in BP software to decompose the program and send it to the device to start printing. Step 23: After printing, remove the part from the additive manufacturing equipment and clean the powder. Step 3: First round of post-processing; The first round of post-processing includes material heat treatment, wire cutting, support removal, and grinding to obtain a solid blank; Step 4: Perform a 3D scan of the solid blank; Perform a 3D scan on the solid blank to obtain the 3D scan result. Use the software Geomagic Control X to compare the obtained 3D scan result with the original blank model in step 1 to obtain the comparison result. Step 5: Processing the physical iterative model; The blank model after pre-deformation in step 1 is adjusted based on the comparison results obtained in step 4. Step 6: Laser powder bed fusion additive manufacturing; For the blank model printed in the new round after physical iterative model processing, printing supports are added again; after the supports are added, the program is divided using Magics software and the BP software that comes with the equipment, and then sent to the printing equipment and the printing work is started; after printing is completed, the parts are removed from the additive manufacturing equipment and the powder is cleaned. Step 7: Post-iteration processing; Post-processing includes material heat treatment, wire cutting, support removal, and grinding.

[0007] Furthermore, in step 1, the simulation process includes the following sub-steps: Step 11: First, add auxiliary supports to the overhanging and suspended surfaces of the blank model in Magics software; Step 12: After adding the support, import the blank model into Simufact Additive software, set the printing equipment size, substrate size and material properties, and then generate a mesh for simulation. Step 13: After the simulation is completed, obtain the simulation results. Based on the simulation results, give the pre-deformation ratio and then perform a new round of simulation iteration. The Magics software will simulate the blank model after inverse deformation according to the given pre-deformation ratio. Repeat this process until the simulation results reach the required state.

[0008] Furthermore, in step 3, the post-processing procedures differ for different materials.

[0009] Furthermore, in step 3, for aluminum alloys and titanium alloys, the post-processing procedure is as follows: after the powder cleaning is completed, the part and the substrate are placed directly in the heat treatment furnace for annealing heat treatment; after annealing heat treatment, wire cutting is performed to cut the part off the substrate, thereby separating the part from the substrate; then, the support added to the part is removed and the support added surface is polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

[0010] Furthermore, in step 3, for high-temperature alloy materials, the post-processing procedure is as follows: after the powder is removed, the part and substrate are placed directly into a heat treatment furnace for annealing heat treatment; after annealing, wire cutting is performed to cut the part off the substrate, thus separating the part from the substrate; the part with support is placed in a heat treatment furnace and subjected to solution aging heat treatment according to the solution aging heat treatment regime of the material; after heat treatment, the support added to the part is removed and the support added surface is polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

[0011] Furthermore, in step 3, the annealing regime is 450~600℃ / 1h~4h / AC.

[0012] Furthermore, in step 5, the Zbrush sculpting software is used to adjust the blank model after pre-deformation in step 1 based on the deformation of the first round of printing results in step 4, in order to compensate for the deformation it produces.

[0013] Furthermore, in step 5, if the physical blank produced in the first round is concave at a certain position relative to the theoretical model, and the concavity is X mm, then the Zbrush software is used to drag this position on the basis of the first round pre-deformation blank model, so that it is dragged outward by X mm on the basis of the first round pre-deformation. This operation is performed on all positions where concavity occurs, to obtain a new round of printing model.

[0014] Furthermore, in step 5, if the physical blank produced in the first round bulges outward at a certain position relative to the theoretical model, with an outward bulge of X mm, then the Zbrush software is used to knead the position on the basis of the first round pre-deformed blank model, so that it is kneaded inward by X mm on the basis of the first round pre-deformation. This operation is performed on all positions where outward bulge occurs, to obtain a new round of printed blank model.

[0015] Furthermore, the specifications for ultra-large thin-walled complex structural components are: structural components that are greater than 500mm×500mm in both the X and Y axes and greater than 300mm in the Z axis; or, structural components that are greater than 500mm in the Z axis and greater than or equal to 250mm×250mm in both the X and Y axes.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: (1) This invention, by simulating and pre-deforming the parts, can more accurately predict and control deformation, reducing the need for support structures and requiring only auxiliary supports on the suspended surface to assist printing. This helps to minimize material waste, reduce manufacturing costs, and promote sustainable production.

[0017] (2) The forming method of the present invention can improve the quality of printed parts: The quality of L-PBF additive manufacturing products is crucial for product applications. In the present invention, the auxiliary supports (used to maintain shape and ensure surface accuracy) are significantly reduced, which can greatly reduce the probability of cracking and powder ejection during the printing process; and, when removing the support during post-processing, the occurrence of local defects due to operational errors is also reduced accordingly. Therefore, the present invention can improve the quality of finished products, reduce the scrap rate, and save time and resources.

[0018] (3) Through simulation, pre-deformation and physical iteration, the deformation of the parts can be effectively controlled within the acceptable range, achieving better deformation control, thereby ensuring good surface accuracy, with 100% surface accuracy within ±0.5mm.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 is a schematic diagram of the high-temperature alloy compartment in Example 1; Figure 2a Left view of the titanium alloy compartment provided in Example 2; Figure 2b This is a front view of the titanium alloy compartment provided in Example 2; Figure 2c This is a side view of the titanium alloy compartment provided in Example 2. Detailed Implementation

[0021] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0022] This invention provides a laser powder bed melting forming method for ultra-large thin-walled complex structural parts. The forming object is an ultra-large thin-walled complex structural part with the following specifications: a structural part that is greater than 500mm × 500mm in both the X and Y axes and greater than 300mm in the Z axis; or a structural part that is greater than 500mm in the Z axis and greater than or equal to 250mm × 250mm in both the X and Y axes.

[0023] The laser powder bed melting forming method for ultra-large thin-walled complex structural parts provided by this invention has the following iterative optimization process: simulation + pre-deformation - first-round laser powder bed melting additive manufacturing - first-round post-processing - three-dimensional scanning of the solid blank - physical iterative model processing - laser powder bed melting additive manufacturing - iterative post-processing.

[0024] The present invention provides a laser powder bed melting forming method for ultra-large thin-walled complex structural parts, comprising the following steps: Step 1: Simulation + Pre-deformation; First, a blank model is established, and then supports are added to the blank model. The laser powder bed melting process is simulated using Simufact Additive software to predict the deformation of the blank model and obtain the simulation results of the blank model. Based on the simulation results, the blank model is pre-deformed using Simufact Additive software, and the pre-deformation ratio is set to 0.6~1.

[0025] It should be noted that the pre-deformation ratio is defined as follows: when the simulation results show that the deformation at a certain position is 1mm, it is defined as convex; for example, when the pre-deformation ratio is set to 0.8, it is necessary to pre-concave 0.8mm at that position in the blank model.

[0026] In step 1 above, the simulation process includes the following sub-steps: Step 11: First, add auxiliary supports to the overhanging and suspended surfaces of the blank model in Magics software; Step 12: After adding the support, import the blank model into Simufact Additive software, set the printing equipment size, substrate size and material properties, and then generate a mesh for simulation. Step 13: After the simulation is completed, obtain the simulation results. Based on the simulation results, give the pre-deformation ratio and then perform a new round of simulation iteration. The Magics software will simulate the blank model after inverse deformation according to the given pre-deformation ratio. Repeat this process until the simulation results meet the requirements.

[0027] In step 13 above, the deformation is observed through the first round of simulation results. Using the anti-deformation function of Magics software, the imported blank model is pre-deformed according to the first round of simulation results: during pre-deformation, the protruding position is pressed back and the concave position is pulled outward to form a new blank model. Then the simulation is repeated until the simulation iteration results meet the requirements.

[0028] In this invention, the pre-deformation ratio is set to 0.6~1. The larger the pre-deformation ratio is set, the more obvious the deformation effect is, and the fewer iterations are needed to reach a relatively ideal state. The smaller the pre-deformation ratio is set, the more iterations are needed, but the iteration results are relatively more accurate. Therefore, this invention sets the pre-deformation ratio in the range of 0.6-1, which can balance the number of iterations and the accuracy of the results.

[0029] Compared with existing technologies, this invention, by controlling the pre-deformation ratio within the range of 0.6 to 1, effectively balances the number of iterations with simulation and printing efficiency while ensuring final molding accuracy. If the pre-deformation ratio is too large, for example, exceeding 1, it may lead to overcompensation, causing the deviation direction between the initial printed blank and the target model to reverse, requiring more iterations for correction, increasing the overall process time and cost. Conversely, if the ratio is too small, such as below 0.6, the compensation effect of a single pre-deformation is limited. To achieve the ideal surface accuracy, more rounds of simulation iterations, model adjustments, printing, and post-processing are necessary, extending the production cycle and increasing equipment occupancy and material consumption. Setting the ratio between 0.6 and 1 significantly reduces the deviation caused by initial deformation through reasonable pre-compensation, thus reducing the number of subsequent iterations, while avoiding new deviation problems caused by overcompensation. This ensures that each iteration effectively approaches the target accuracy, ultimately achieving the expected surface accuracy requirements quickly with relatively few iterations.

[0030] Step 2: First round of laser powder bed fusion additive manufacturing; Step 21: Convert the format of the blank model after pre-deformation to STL format, and re-add printing supports to the blank model in Magics software; the printing supports should be added strictly according to the printing requirements to ensure the printing success rate. Step 22: After the print support is added, use Magics software and the device's built-in BP software to perform program breakdown and send it to the device to start the printing work. Step 23: After printing is complete, remove the part from the additive manufacturing equipment and clean the powder.

[0031] It should be noted that when adding printing supports to the pre-deformed blank model, the supports used for simulation are relatively simple and have less contact with the part; while the supports added during printing are relatively complete and complex and can contact the part.

[0032] Compared with existing technologies, the advantages of the differentiated support strategy adopted in this invention are as follows: In the simulation stage, using relatively simple supports with less contact with the part simplifies the simulation model, reduces the complexity of mesh generation, and decreases the amount of simulation calculation, thereby improving simulation efficiency and quickly obtaining key data required for deformation trends and pre-deformation. Simultaneously, by reducing auxiliary support structures, the risk of defects caused by support cracking or powder ejection during printing is reduced, thus improving forming quality and production efficiency. In the actual printing stage, adding relatively complete and complex supports ensures the structural stability of the part during printing, effectively resisting thermal stress and gravity during forming, preventing collapse and warping defects, and ensuring smooth printing and initial forming quality. This differentiated approach between simulation and printing supports satisfies the simulation's requirements for efficiency and key deformation information acquisition while ensuring the reliability of actual printing, achieving an organic combination of simulation guidance and actual operation.

[0033] Step 3: First round of post-processing; The first round of post-processing includes material heat treatment, wire cutting, support removal, and grinding to obtain a solid blank.

[0034] It should be noted that the post-processing procedures differ for different materials, as follows: For aluminum alloys and titanium alloys: After the powder cleaning is completed, the parts and substrate are placed directly into the heat treatment furnace for annealing heat treatment according to the heat treatment regime of the material; after heat treatment, wire cutting is performed to cut the parts off the substrate to separate the parts from the substrate; then, the supports added to the parts are removed and the support added surfaces are polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

[0035] For high-temperature alloys: After powder cleaning, the parts and substrate are placed directly into a heat treatment furnace for annealing heat treatment. The annealing regime is 450~600℃ / 1h~4h / AC, and the solution aging is carried out according to the respective standards. After annealing, wire cutting is performed to cut the parts off the substrate to separate the parts from the substrate. The blank with supports is placed in a heat treatment furnace and solution aging heat treatment is performed according to the solution aging heat treatment regime of the material. After heat treatment, the supports added to the parts are removed and the support-added surfaces are polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

[0036] The purpose of the aforementioned annealing heat treatment is to remove internal stress generated during the printing process. This invention uses annealing heat treatment instead of direct solution stress relief and strengthening treatment because for parts with internal cavity structures, there is residual powder inside the cavity. If solution stress relief and strengthening treatment were directly performed, the residual powder in the cavity would clump together and cannot be cleaned out. Therefore, this invention, by adding annealing heat treatment, allows for better cleaning of the internal cavity powder after separation from the substrate.

[0037] Furthermore, the annealing heat treatment control regime of this invention is 450~600℃ / 1h~4h / AC. The purpose is that if the solution treatment temperature is too high, the substrate will fail and become unusable when the part and substrate are solution treated together, and there is a high risk of cracking at the connection between the substrate and the part. Therefore, stress-relieving annealing is required before solution aging to eliminate internal stress in the part. After annealing, the substrate is separated by wire cutting, and then the part undergoes solution aging.

[0038] This invention first performs annealing heat treatment, annealing the part along with the substrate. This is because the substrate and its support reduce deformation of the part, thus better ensuring surface accuracy. After annealing, wire cutting is used to separate the part from the substrate, and then solution aging treatment is performed with the support still in place.

[0039] Compared with existing technologies, this invention ensures that L-PBF formed parts achieve the best results in removing thermal stress, optimizing microstructure and properties, and achieving final dimensional accuracy and surface quality by customizing specific heat treatment (such as annealing, solution aging) and machining (wire cutting, support removal, grinding) processes for different alloy materials (such as aluminum alloys, titanium alloys, and high-temperature alloys). It avoids material property degradation or secondary deformation that may be caused by general post-processing, thereby significantly improving the reliability and service life of the product. This is the key to ensuring the final performance of ultra-large thin-walled complex structural parts.

[0040] Step 4: Perform a 3D scan of the solid blank; Perform a 3D scan on the solid blank to obtain the 3D scan result. Use the software Geomagic Control X to compare the obtained scan result with the original blank model in step 1 to obtain the comparison result, that is, the actual deformation of the solid blank.

[0041] Step 5: Processing the physical iterative model; Based on the comparison results obtained in step 4, the blank model after pre-deformation in step 1 is adjusted. The specific process is as follows: using Zbrush sculpting software, the blank model after pre-deformation in step 1 is adjusted according to the deformation of the first round of printing results in step 4 to compensate for the deformation.

[0042] For example, if the physical blank produced in the first round of research and development is concave at a certain position relative to the theoretical model, and the concavity is X mm, then the Zbrush software is used to drag this position on the basis of the first round of pre-deformation blank model, so that it is dragged outward by X mm on the basis of the first round of pre-deformation. This operation is performed on all positions where concavity occurs, and a new round of printing model is obtained.

[0043] If the physical blank produced in the first round of research and development bulges outward at a certain position relative to the theoretical model, with a bulge of X mm, then the Zbrush software is used to knead that position on the basis of the first round of pre-deformed blank model, so that it is kneaded inward by X mm on the basis of the first round of pre-deformation. This operation is performed on all positions where bulging occurs, to obtain a new round of printed blank model.

[0044] Compared with existing technologies, this invention, by clearly defining the principle of "adjusting convexities inward and concaveities outward," and emphasizing compensation "while ensuring wall thickness," ensures the effectiveness of iterative adjustments and structural integrity. This design can accurately offset residual deformation errors generated in actual manufacturing, avoiding over-compensation or under-compensation, thereby accelerating the convergence of the iterative process and enabling the final product to achieve the expected surface accuracy with fewer iterations.

[0045] Step 6: Laser powder bed fusion additive manufacturing; For the blank model that has undergone physical iterative modeling, new printing supports are added. The addition process must strictly adhere to printing requirements to ensure a high printing success rate. After the supports are added, the program is partitioned using Magics software and the device's built-in BP software, then sent to the printing equipment and the printing process is initiated. After printing is complete, the parts are removed from the additive manufacturing equipment and the powder is cleaned.

[0046] Step 7: Post-iteration processing; Post-processing includes material heat treatment, wire cutting, support removal, and grinding; the post-processing procedures vary depending on the material.

[0047] For aluminum alloys and titanium alloys: After the powder cleaning is completed, the parts and substrate are placed directly into the heat treatment furnace for heat treatment according to the heat treatment regime corresponding to the material; after heat treatment, wire cutting is performed to separate the parts from the substrate and cut them off from the substrate; the supports added to the parts are removed and the support added surfaces are polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

[0048] For high-temperature alloys: After powder cleaning, the parts, along with the substrate, are directly placed in a heat treatment furnace for annealing heat treatment. Annealing is performed according to the annealing heat treatment regime corresponding to the material, which is 450~600℃ / 1h~4h / AC. After annealing, the parts are separated from the substrate using wire cutting and cut off from the substrate. The blank with supports is then placed in a heat treatment furnace for solution aging heat treatment, strictly following the solution aging heat treatment regime of the material. After heat treatment, the supports added to the parts are removed, and the surfaces with added supports are polished to ensure a smooth surface, free of support residue and burrs, thus obtaining a solid blank.

[0049] It should be explained that the support added in the above steps of this invention is an auxiliary support, which is an essential shape support structure in printing. It plays a role in limiting deformation during the printing and heat treatment of parts, that is, it assists in supporting large planes, suspended surfaces, and hanging surfaces to prevent them from deforming.

[0050] This invention significantly reduces the need for numerous "shape supports" in traditional L-PBF processes by implementing a multi-stage, differentiated support strategy combined with pre-deformation technology. This design effectively reduces material waste and manufacturing costs, simplifies post-processing (reducing the workload and difficulty of support removal), and, by reducing the support structure, lowers the risk of defects caused by support cracking or powder ejection during printing, thereby improving forming quality and production efficiency.

[0051] In summary, this invention first adds supports to the blank model, performs simulation and pre-deformation processing. The pre-deformed blank model is then exported, and supports are added again strictly according to printing requirements, followed by segmentation. The program is then sent to the equipment for printing. After printing, a part removal and powder cleaning operation is performed, along with post-processing (including heat treatment, wire cutting, and support removal) to obtain a solid blank. A 3D scan of the solid blank is then performed, and the obtained 3D scan results are compared with the original blank model (i.e., the blank model before pre-deformation) to clarify the deformation situation.

[0052] Based on the deformation, the deformed areas are sculpted, essentially undergoing further anti-deformation work. This yields the blank model required for the next round of printing. After adding printing supports and performing a sectionalization process, the model is sent to the equipment to begin a new round of printing. Post-processing is performed after printing to obtain an iterated solid blank, which allows for controlled deformation.

[0053] This invention enables near-net-shape forming of ultra-large, thin-walled, complex structural components. By machining only the assembly surfaces, this invention ensures surface and dimensional accuracy, and the method is convenient and quick, requiring minimal post-processing.

[0054] The simulation stage of this invention utilizes specialized software (such as Simufact Additive) to accurately predict the thermal stress distribution and deformation trend of parts during the printing process, thus "predicting" deformation before physical manufacturing. In the pre-deformation stage, based on the simulation prediction results, this invention actively compensates the digital model geometrically. That is, it "reverses" the model during the design phase, ensuring that the deformation caused by thermal stress during actual printing precisely offsets the preset reverse deformation, resulting in a final part that closely approximates the ideal shape. After obtaining the physical part through the first round of additive manufacturing, its true 3D data is acquired through 3D scanning and compared with the original design model, accurately "verifying" the effect of the pre-deformation and quantifying the residual deformation error. The physical iterative model adjustment stage further refines the digital model with reverse compensation based on the deviation between the actual scan data and the ideal model, forming a more optimized model. This iterative process allows each print to be corrected and optimized based on the previous one, gradually approaching the zero-deformation target, ultimately achieving efficient control over the surface accuracy of ultra-large, thin-walled, complex structural parts. This method not only effectively controls deformation but also reduces the need for a large number of shape supports, thereby reducing material waste and post-processing costs.

[0055] In summary, this invention solves the deformation problem caused by thermal stress in ultra-large thin-walled complex structural parts during laser powder bed melting and forming by establishing a closed-loop control mechanism of "prediction-compensation-verification-iterative adjustment".

[0056] The laser powder bed melting process and results for several different components are described in detail below.

[0057] Example 1 The ultra-large thin-walled complex structural component in this embodiment is a GH4099 high-temperature alloy section with an envelope size of 500mm × 370mm × 970mm. Its blank model is as follows: Figure 1 As shown. The laser powder bed melting process for this ultra-large, thin-walled, complex structural component is as follows: Step 1: Simulation + Pre-deformation; A blank model is established, and then supports are added to the blank model. The laser powder bed melting process is simulated using Simufact Additive software to predict the deformation of the blank model and obtain the simulation results. The specific process includes: Step 11: First, add auxiliary supports to the overhanging and suspended surfaces of the blank model in Magics software; Step 12: After adding the support, import the blank model into Simufact Additive software, set the printing equipment size, substrate size and material properties, and then generate a mesh for simulation. Step 13: After the simulation is completed, obtain the simulation results. Based on the simulation results, give the pre-deformation ratio and then perform a new round of simulation iteration. The Magics software will simulate the blank model after inverse deformation according to the given pre-deformation ratio. Repeat this process until the simulation results meet the requirements.

[0058] In step 13 above, the deformation is observed through the first round of simulation results. Using the anti-deformation function of Magics software, the imported blank model is anti-deformed according to the first round of simulation results: the pre-anti-deformation ratio is set to 1, and the deformation position is completely anti-deformed.

[0059] Step 2: First round of powder bed melt additive manufacturing; Step 21: Convert the format of the pre-deformed blank model to STL format, and re-add supports to the blank model in Magics software. Step 22: Use the built-in BP software of the device to split the program and send it to the device to start the printing work; Step 23: After printing is complete, remove the part from the additive manufacturing equipment and clean the powder.

[0060] Step 3: First round of post-processing; After the powder is removed, the part and the substrate are placed directly into a heat treatment furnace for annealing at 500℃ for 2 hours. After annealing, wire cutting is performed to cut the part off the substrate. The blank with support is placed in a heat treatment furnace for solution aging heat treatment (1150℃ for 2 hours + 800℃ for 8 hours). After heat treatment, the support added to the part is removed and the support added surface is polished to ensure that the surface is smooth without support residue and burrs. At this point, a solid blank is obtained.

[0061] Step 4: Perform a 3D scan to obtain the first round of scan results; A 3D scan of the blank was performed, and the 3D scan results were compared with the blank model using the software Geomagic Control X to check the deformation of the blank. The surface accuracy was within ±0.5mm for 80% of the time.

[0062] Step 5, Physical Iteration: Adjust the blank model based on the comparison results; Using ZBrush sculpting software, the out-of-tolerance areas of the model are sculpted based on the 3D scanning results. For protruding areas, the model is sculpted inward, and for concave areas, the model is sculpted outward. While ensuring the wall thickness, the out-of-tolerance areas are deformed in the opposite direction to compensate for the deformation, thus obtaining the second-round printed model.

[0063] Step 6: Iterative powder bed melt additive manufacturing; The processed printing model is supported by Magics software, and the program is split and sent to the equipment using the built-in BP software to start the printing process. After printing, the part is removed from the additive manufacturing equipment for powder cleaning.

[0064] Step 7: Post-iteration processing (final scan result); Similar to the first round of post-processing in step 3 above, a solid blank is finally obtained. The solid blank is then 3D scanned, and the 3D scan results are compared with the original blank model using the software Geomagic Control X. The surface accuracy is 100% within ±0.5mm, which is a significant improvement.

[0065] Example 2 The ultra-large thin-walled complex structural component in this embodiment is a TA15 titanium alloy section with an envelope size of Φ540mm × 178mm, and its blank model is as follows. Figures 2a to 2c As shown; the laser powder bed melting process for this ultra-large thin-walled complex structural component is as follows: Step 1: Simulation + Pre-deformation; A blank model was established and supports were added to the blank model. The laser powder bed melting process was simulated using Simufact Additive software. After the simulation, Simufact Additive software was used to perform pre-deformation on the model based on the simulation results. The pre-deformation ratio was set to 1, and the deformation position was completely reversed.

[0066] Step 2: First round of powder bed melt additive manufacturing; The blank model is converted to STL format. Supports are added to the pre-deformed blank model using Magics software. The built-in BP software is then used to perform program segmentation and send the data to the equipment for printing. After printing, the part is removed from the additive manufacturing equipment for powder cleaning.

[0067] Step 3: First-round post-processing After the powder is removed, the parts and substrate are placed directly into a heat treatment furnace for annealing at 800℃ for 4 hours. After annealing, wire cutting is performed to cut the parts off the substrate. After wire cutting, the fitter removes the supports added to the parts and polishes the support surfaces to ensure that the surface is smooth without any support residue or burrs, thus obtaining a solid blank.

[0068] Step 4: 3D Scan (Results of the First Round of Scans) A 3D scan of the blank was performed, and the 3D scan results were compared with the blank model using the software Geomagic Control X to check the deformation of the blank. The results showed that the surface accuracy of the first round of printing reached within ±0.5mm in 80% of the area.

[0069] Step 5, Physical Iteration: Adjust the blank model based on the comparison results; Using sculpting software such as ZBrush, the out-of-tolerance areas of the model are sculpted based on the 3D scan results. Protruding areas are sculpted inwards, and concave areas are sculpted outwards. While maintaining the wall thickness, the out-of-tolerance areas are then deformed in the opposite direction to obtain the second-round printed model.

[0070] Step 6: Iterative Powder Bed Melting Additive Manufacturing The processed printing model is supported by Magics software, and the program is split and sent to the equipment using the built-in BP software to start the printing process. After printing, the part is removed from the additive manufacturing equipment for powder cleaning.

[0071] Step 7: Post-iteration processing (final scan result) Similar to the initial post-processing in step 3 above, a solid blank is finally obtained. A 3D scan is then performed on it, and the results are compared with the original blank model using Geomagic Control X software. The surface accuracy is 100% within ±0.5mm, showing significant improvement.

[0072] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser powder bed melting forming method for ultra-large thin-walled complex structural parts, characterized in that, Includes the following steps: Step 1: Simulation + Pre-deformation; First, a blank model is established, and then supports are added to the blank model. The laser powder bed melting process is simulated using Simufact Additive software to predict the deformation of the blank model and obtain the simulation results of the blank model. Based on the simulation results, the blank model is pre-deformed using Simufact Additive software, and the pre-deformation ratio is set to 0.6~1. Step 2: First round of laser powder bed fusion additive manufacturing; Step 21: Convert the format of the blank model after pre-deformation to STL format, and re-print the blank model and add supports in Magics software. Step 22: After the support is added, use Magics software and the device's built-in BP software to decompose the program and send it to the device to start printing. Step 23: After printing, remove the part from the additive manufacturing equipment and clean the powder. Step 3: First round of post-processing; The first round of post-processing includes material heat treatment, wire cutting, support removal, and grinding to obtain a solid blank; Step 4: Perform a 3D scan of the solid blank; Perform a 3D scan on the solid blank to obtain the 3D scan result. Use the software Geomagic Control X to compare the obtained 3D scan result with the original blank model in step 1 to obtain the comparison result. Step 5: Processing the physical iterative model; The blank model after pre-deformation in step 1 is adjusted based on the comparison results obtained in step 4. Step 6: Laser powder bed fusion additive manufacturing; For the new round of printed blank models formed after the physical iterative model processing, printing supports are added again; After the printing support is added, the program is divided using Magics software and the device's built-in BP software, and then sent to the printing device and the printing work is started. After printing is complete, remove the part from the additive manufacturing equipment and clean up the powder; Step 7: Post-iteration processing; Post-processing includes material heat treatment, wire cutting, support removal, and grinding.

2. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 1, characterized in that, In step 1, the simulation process includes the following sub-steps: Step 11: First, add auxiliary supports to the overhanging and suspended surfaces of the blank model in Magics software; Step 12: After adding the support, import the blank model into Simufact Additive software, set the printing equipment size, substrate size and material properties, and then generate a mesh for simulation. Step 13: After the simulation is completed, obtain the simulation results. Based on the simulation results, give the pre-deformation ratio and then perform a new round of simulation iteration. The Magics software will simulate the blank model after inverse deformation according to the given pre-deformation ratio. Repeat this process until the simulation results reach the required state.

3. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 1, characterized in that, In step 3, the post-processing procedures differ for different materials.

4. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 3, characterized in that, In step 3, for aluminum alloys and titanium alloys, the post-processing procedure is as follows: after the powder is removed, the part and the substrate are placed directly into a heat treatment furnace for annealing heat treatment; after annealing heat treatment, wire cutting is performed to cut the part off the substrate, thereby separating the part from the substrate; then, the support added to the part is removed and the support added surface is polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

5. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 3, characterized in that, In step 3, for high-temperature alloy materials, the post-processing procedure is as follows: after the powder is removed, the part and substrate are placed directly into a heat treatment furnace for annealing heat treatment; after annealing, wire cutting is performed to cut the part off the substrate, thus separating the part from the substrate; the part with support is placed in a heat treatment furnace and subjected to solution aging heat treatment according to the solution aging heat treatment regime of the material; after heat treatment, the support added to the part is removed and the support added surface is polished to ensure that the surface is smooth without support residue and burrs, thus obtaining a solid blank.

6. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 1, characterized in that, In step 3, the annealing process is 450~600℃ / 1h~4h / AC.

7. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 1, characterized in that, In step 5, the Zbrush sculpting software is used to adjust the blank model after pre-deformation in step 1 based on the deformation of the first printing result in step 4, in order to compensate for the deformation.

8. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 7, characterized in that, In step 5, if the physical blank produced in the first round is concave at a certain position relative to the theoretical model, and the concavity is X mm, then the Zbrush software is used to drag this position on the basis of the first round pre-deformation blank model, so that it is dragged outward by X mm on the basis of the first round pre-deformation. This operation is performed on all positions where concavity occurs to obtain a new round of printing model.

9. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to claim 7, characterized in that, In step 5, if the physical blank produced in the first round bulges outward at a certain position relative to the theoretical model, with a bulge of X mm, then the Zbrush software is used to knead the position on the basis of the first round pre-deformed blank model, so that it is kneaded inward by X mm on the basis of the first round pre-deformation. This operation is performed on all positions where bulge occurs, to obtain a new round of printed blank model.

10. The laser powder bed melting forming method for ultra-large thin-walled complex structural parts according to any one of claims 1 to 9, characterized in that, The specifications of the ultra-large thin-walled complex structural component are: a structural component that is greater than 500mm×500mm in both the X and Y axis directions and greater than 300mm in the Z axis direction; Alternatively, it can be greater than 500mm in the Z-axis direction and greater than or equal to 250mm × 250mm in the X and Y directions.

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