Light-weight and high-cleanliness manufacturing method of low-expansion alloy optical-mechanical structure

Abstract

The invention relates to the technical field of selective laser melting forming of low-expansion alloy structural parts, in particular to a light-weight and high-cleanliness manufacturing method of a low-expansion alloy optical-mechanical structure. According to the invention, static simulation analysis of the optical-mechanical structure is carried out; establishing a three-dimensional model of the optical-mechanical structure; a contour adding entity support is installed in a top frame of the optical-mechanical structure; the method comprises the steps that SLM forming process simulation analysis of an optical-mechanical structure is conducted, the residual stress and the deformation rule of the optical-mechanical structure are obtained, the deformation amount is controlled within a preset range so that an SLM forming three-dimensional model can be obtained, and based on the SLM forming three-dimensional model, a data packet capable of being recognized by SLM forming equipment is determined; and performing vacuum heat treatment after the SLM forming of the optical-mechanical structure is finished. According to the low-expansion alloy optical-mechanical structure, the re-lightweight design of the low-expansion alloy optical-mechanical structure is achieved, the outer contour compensates for the skin, the integrity and rigidity of the formed part are guaranteed, the manufacturing process of the invar steel part is effectively simplified, the manufacturing efficiency and the material utilization rate are greatly improved, and cost is reduced.

Description

Technical Field

[0001] This disclosure relates to the field of selective laser melting forming technology for low-expansion alloy structural components, and in particular to a lightweight and highly clean manufacturing method for low-expansion alloy optomechanical structures. Background Technology

[0002] Selective Laser Melting (SLM) technology uses a laser as an energy source to scan a bed of high-temperature alloy powder layer by layer according to a pre-planned path in a 3D CAD slicing model. The scanned high-temperature alloy powder melts and solidifies to achieve a metallurgical bond, ultimately producing the metal part designed in the model. It can be used for the direct manufacturing of complex parts and the manufacturing of near-end metal products, offering advantages such as short forming cycles, high precision and performance of formed components, high material utilization, and low manufacturing costs. Currently, SLM forming technology is rapidly developing. Large-format multi-beam SLM equipment, through multi-beam splicing, can form parts with a width exceeding 1 meter, providing an innovative technological approach for the integrated structural and functional manufacturing of large, low-expansion Invar alloy parts.

[0003] Invar steel parts are typical large, low-expansion alloy parts with a weight-reducing deep cavity mesh reinforcement structure, with an envelope of approximately 1 meter. The frame beams are designed with mesh reinforcements of varying sizes, ranging from 100mm to 220mm, with a wall thickness of 4mm and a height of 90-120mm. These mesh reinforcements exhibit a large aspect ratio and thin walls. Traditional manufacturing processes involve casting followed by machining into individual vertical plate components, which are then assembled and welded together. On the one hand, a large amount of Invar alloy is removed during mesh reinforcement machining, resulting in a material utilization rate of less than 10%, long processing cycles, and high costs. On the other hand, welding connections involve large-thickness welds, leading to problems such as incomplete penetration and difficulty in controlling deformation. Therefore, it is difficult to guarantee the dimensional accuracy and coefficient of linear expansion of the Invar steel parts, as well as their stiffness and stiffness stability. Furthermore, the large aspect ratio mesh reinforcement requires cleaning each dense mesh reinforcement individually during cleaning, which is difficult and time-consuming. Summary of the Invention

[0004] This disclosure aims to address at least one of the technical problems existing in the prior art or related technologies.

[0005] Therefore, this disclosure provides a lightweight and high-cleanliness manufacturing method for low-expansion alloy optomechanical structures, including:

[0006] Structural analysis includes static simulation analysis of the optomechanical structure, which includes equivalent stress, strain, and safety factor.

[0007] Additive manufacturing is used to create a three-dimensional model of the optical-mechanical structure.

[0008] Skin reinforcement: Skin is added to the outer contour of the optical-mechanical structure;

[0009] The forming direction is the direction perpendicular to the horizontal substrate of the vertical frame of the optomechanical structure;

[0010] The allowance is added by adding a preset allowance to the contact surface between the optomechanical structure and the substrate, the assembly holes of the vertical frame, and the assembly surface of the top frame;

[0011] Solid supports are installed within the top frame of the optomechanical structure to add contour-based solid supports.

[0012] Simulation analysis is performed on the SLM forming process of the optomechanical structure to obtain its residual stress and deformation law. The deformation is controlled within a preset range to obtain a three-dimensional model of SLM forming. Based on the three-dimensional model of SLM forming, the data packets that the SLM forming equipment can recognize are determined.

[0013] SLM forming, the data package includes laser power, scanning speed, spot diameter, powder thickness and scanning spacing;

[0014] After the SLM forming of the optomechanical structure is completed, it undergoes vacuum heat treatment, followed by annealing stress relief treatment, solution heat treatment, tempering treatment, stabilization treatment, and post-treatment.

[0015] In one feasible implementation, the thickness of the mesh reinforcement wall of the optomechanical structure is set to 2 mm to 3 mm, and the height of the mesh reinforcement wall is set to 70 mm to 100 mm.

[0016] In one feasible implementation, in the skin reinforcement step, the added skin thickness is set to 1 mm to 2 mm.

[0017] In one feasible implementation, in the skin reinforcement step, a lattice structure is added between the skin mesh reinforcements to reinforce the structure. The lattice structure is a face-centered cubic or body-centered cubic lattice structure based on the support column.

[0018] In one feasible implementation, the unit cell diameter of the face-centered cubic or body-centered cubic lattice structure is set to 2 mm to 6 mm, and the rod diameter is 0.5 mm to 2 mm.

[0019] In one feasible implementation, in the step of adding the allowance, the preset allowance is set to add 5mm allowance to the contact surface between the optomechanical structure and the substrate, 2mm allowance to the round hole of the vertical frame assembly, and 2mm allowance to the top frame assembly surface.

[0020] In one feasible implementation, the solid support is configured to add a solid columnar support to the top of the circular hole in the upright frame, and add block-shaped supports to the lower surface of the top frame cantilever structure and the top of the upright frame.

[0021] In one feasible implementation, during the SLM forming step, the data packet settings parameters for the block support are: laser power of 300W to 400W, scanning speed of 1000mm / s to 1600mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

[0022] In one feasible implementation, during the SLM forming step, the data packet parameters are: laser power of 300W to 400W, scanning speed of 800mm / s to 1000mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

[0023] In one feasible embodiment, the annealing stress relief treatment temperature is set to 530°C to 550°C and held for 1 to 2 hours; the solution heat treatment temperature is set to 830°C to 860°C and held for 0.5 to 1 hour; the tempering treatment temperature is set to 305°C to 325°C and held for 1 to 4 hours; the stabilization treatment temperature is set to 85°C to 105°C and held for 48 to 50 hours; the vacuum degree of the annealing stress relief treatment, the solution heat treatment, the tempering treatment, and the stabilization treatment is 10⁻³ to 10⁻² Pa.

[0024] The above description is merely an overview of the technical solution provided in this disclosure. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other features and effects of this disclosure more obvious and understandable, the following are specific examples of the implementation methods of this disclosure. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0026] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of exemplary embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0028] Figure 1 This is a schematic diagram of the forming direction structure of this disclosure;

[0029] Figure 2 This is a structural schematic diagram of the top frame assembly surface and the vertical frame assembly circular holes of this disclosure;

[0030] Figure 3 This is a structural schematic diagram of the frame assembly circular hole and the bottom end of the optomechanical structure disclosed herein;

[0031] Figure 4 This is a schematic diagram of the structure supporting the entity disclosed herein;

[0032] Figure 5 For this disclosure Figure 4 Schematic diagram of the cross-sectional structure along the AA direction;

[0033] Figure 6 This is a schematic diagram of the solid column support structure disclosed herein;

[0034] Figure 7 A schematic diagram of the structure of the dot matrix mechanism disclosed herein;

[0035] Figure 8 For this disclosure Figure 7 A schematic diagram of the structure at point A in the middle.

[0036] in, Figures 1 to 8 The correspondence between the reference numerals and component names in the attached drawings is as follows: 100-skin; 200-base plate; 300-round hole for mounting the vertical frame; 400-mounting surface of the top frame; 500-solid support; 501-solid columnar support; 600-bottom end; 700-matrix structure. Detailed Implementation

[0037] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0038] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0039] Currently, SLM forming technology is developing rapidly. Large-format multi-beam SLM equipment can form the integral manufacturing of parts with a width of more than 1m by splicing multiple beams, providing an innovative technical approach for the integrated manufacturing of large low-expansion Invar alloy parts.

[0040] Invar steel parts are typical large, low-expansion alloy parts with a weight-reducing deep cavity mesh reinforcement structure, with an envelope of approximately 1 meter. The frame beams are designed with mesh reinforcements of varying sizes, ranging from 100mm to 220mm, with a wall thickness of 4mm and a height of 90-120mm. These mesh reinforcements exhibit a large aspect ratio and thin walls. Traditional manufacturing processes involve casting followed by machining into individual vertical plate components, which are then assembled and welded together. On the one hand, a large amount of Invar alloy is removed during mesh reinforcement machining, resulting in a material utilization rate of less than 10%, long processing cycles, and high costs. On the other hand, welding connections involve large-thickness welds, leading to problems such as incomplete penetration and difficulty in controlling deformation. Therefore, it is difficult to guarantee the dimensional accuracy and coefficient of linear expansion of the Invar steel parts, as well as their stiffness and stiffness stability. Furthermore, the large aspect ratio mesh reinforcement requires cleaning each dense mesh reinforcement individually during cleaning, which is difficult and time-consuming. Therefore, it is necessary to introduce SLM forming technology for the overall manufacturing of such Invar steel parts. By leveraging the technological advantage of additive manufacturing in enabling rapid manufacturing of complex structures, and by introducing advanced lightweight structural designs to replace traditional mesh reinforcement structures, lightweight, integrated, efficient, and low-cost manufacturing of Invar steel parts can be achieved while ensuring manufacturing performance.

[0041] Based on this, the embodiments of this disclosure provide a lightweight and high-cleanliness manufacturing method for low-expansion alloy optomechanical structures. This disclosure clearly defines the processes of redesigning the optomechanical structure (Invar parts), redesigning the lightweight structure, anti-deformation simulation, powder material preparation, SLM forming, and post-heat treatment, effectively controlling the accuracy, mechanical properties, and linear expansion performance of the SLM-formed optomechanical structure. This ensures the integrity and rigidity of the formed parts, effectively simplifies the Invar parts manufacturing process, greatly improves manufacturing efficiency and material utilization, and achieves cost reduction.

[0042] The following detailed description, through specific embodiments, illustrates the lightweight and high-cleanliness manufacturing method of this low-expansion alloy optomechanical structure:

[0043] Reference Figures 1 to 8 As shown, this disclosure provides a lightweight and highly clean manufacturing method for low-expansion alloy optomechanical structures, including:

[0044] Structural analysis includes static simulation analysis of the optomechanical structure, which includes equivalent stress, strain, and safety factor.

[0045] Additive manufacturing is used to create a three-dimensional model of the optical-mechanical structure.

[0046] Skin reinforcement: A skin 100 is added to the outer contour of the optical-mechanical structure;

[0047] The forming direction is the direction perpendicular to the vertical frame of the optomechanical structure and the horizontal substrate 200, which is the SLM forming direction;

[0048] The allowance is added by adding a preset allowance to the contact surface between the optomechanical structure and the substrate 200, the mounting hole 300 of the vertical frame, and the mounting surface 400 of the top frame;

[0049] Solid support is provided by installing a contour-added solid support 500 within the top frame of the optical-mechanical structure.

[0050] Simulation analysis is performed on the SLM forming process of the optomechanical structure to obtain its residual stress and deformation law. The deformation is controlled within a preset range to obtain a three-dimensional model of SLM forming. Based on the three-dimensional model of SLM forming, the data packets that the SLM forming equipment can recognize are determined.

[0051] SLM forming, the data package includes laser power, scanning speed, spot diameter, powder thickness and scanning spacing;

[0052] After the SLM forming of the optomechanical structure is completed, it undergoes vacuum heat treatment, followed by annealing stress relief treatment, solution heat treatment, tempering treatment, stabilization treatment, and post-treatment.

[0053] The optomechanical structure metal SLM forming equipment disclosed herein is filled with low-expansion alloy 4J32 powder or 4J36 powder. Specifically, 4J32 powder is used, and a substrate 200 and a scraper are installed. Specifically, the particle size of the low-expansion alloy 4J32 powder is 15–53 μm, and the scraper is a flexible scraper made of wear-resistant plastic material. The substrate 200 is an Invar alloy substrate with good wettability to the component material and a linear expansion coefficient consistent with the component material, with a thickness t = 80–120 mm. Then, model preprocessing is performed. The model preprocessing of this disclosure includes redesigning the Invar steel part structure with mesh reinforcement, selecting the part forming direction, designing the structure and solid support, adding margin, simulation calculation, slicing, and generating the forming program. Specifically, in the structural analysis step, the low-expansion alloy part structure is analyzed, analyzing the part's structural characteristics and the additive manufacturing process design suitable for each structure.

[0054] In the structural analysis step, the optomechanical structure is analyzed using Ansys static simulation software to perform static simulation analysis of the original design structure under actual working conditions. The equivalent stress, strain, and safety factor are recorded after the static simulation analysis. In the additive manufacturing step, the overall additive manufacturing process of the mesh reinforcement is redesigned to ensure that the angle between the mesh reinforcement structure distributed on the outer contour of the optomechanical structure and the horizontal direction is greater than or equal to 45°, and a three-dimensional model of the low-expansion alloy part structure is established. In the skin reinforcement step, a skin 100 is added to the entire outer contour of the optomechanical structure using UG software, with the skin thickness set to 1mm to 2mm. In the forming direction step, the forming direction of the optomechanical structure is selected; specifically, the top frame of the part achieves near-net-shape forming, and the direction perpendicular to the horizontal substrate 200 of the part's vertical frame is the SLM forming direction. In the step of adding allowance, a scheme for adding allowance in the optomechanical structure is designed. A 5mm allowance is added to the contact surface between the part and the substrate (bottom 600), a 2mm allowance is added to the round hole 300 of the vertical frame assembly, and a 2mm allowance is added to the top frame assembly surface 400. In the step of solid support, solid sheet-like supports are added to the contour inside the top frame, and beveled corners with an angle greater than or equal to 45° to the horizontal are designed to reach the inner wall of the vertical frame. Further, a small number of solid column-like supports with a diameter of 1-2mm are added to the top of the round hole of the vertical frame. In the step of simulation analysis, the optomechanical structure forming process simulation analysis is performed. Using SimufactAdditive software, the SLM forming process of the designed part is simulated and analyzed to obtain its residual stress and deformation law. The deformation is controlled within a preset range. Specifically, the preset range is set to add external support or compensation allowance to the position where the local deformation exceeds ±1mm to control its deformation. A new printing model is established and simulation analysis is performed again. Through continuous iteration, the deformation is controlled below ±1mm, thereby obtaining the optimal SLM forming three-dimensional model. In the SLM forming step, the 3D model of the optomechanical structure is sliced. The optimal SLM forming 3D model is sliced ​​to obtain a data package recognizable by the SLM forming equipment. The required process data package settings for the SLM forming step include laser power, scanning speed, spot diameter, powder thickness, and scanning spacing. Specifically, the SLM forming equipment preparation steps include installing and leveling the substrate and scraper; cleaning the laser incident protective lens; installing the suction slot and air inlet baffle; turning on the platform heating; performing gas purging in the forming chamber to ensure the oxygen content in the chamber is ≤200ppm before starting the forming process. In the vacuum heat treatment step, after the optomechanical structure SLM forming is completed, it first undergoes annealing to relieve stress, followed by solution heat treatment and tempering, and finally stabilization treatment. Specifically, the optomechanical structure powder is dried in a vacuum drying oven.

[0055] The post-processing disclosed herein includes substrate removal, support removal, and sandblasting. Post-processing following heat treatment ensures cleanliness and guarantees linear expansion performance, resulting in high-efficiency, low-cost SLM-formed low-expansion mesh frame beam parts. Specifically, the disassembly of the formed optomechanical structure and substrate includes opening the forming chamber, using an explosion-proof vacuum cleaner to clean the chamber door and suction slot for powder, and disassembling the substrate with components. Further, the powder cleaning process includes one or more of vibration-based powder cleaning, compressed air powder cleaning, and ultrasonic cleaning.

[0056] In some embodiments, the thickness of the mesh reinforcement wall of the optomechanical structure is set to 2 mm to 3 mm, and the height of the mesh reinforcement wall is set to 70 mm to 100 mm.

[0057] In this embodiment, the height of the mesh reinforcement walls is set to 70mm to 100mm, forming an efficient load transfer network and avoiding local material redundancy. A mesh reinforcement wall height of 70-100mm significantly increases the moment of inertia of the cross-section, resulting in higher stiffness compared to a solid structure for the same weight. A mesh reinforcement wall thickness of 2mm to 3mm, combined with the mesh topology, helps prevent instability through buckling analysis and increases the critical load.

[0058] In some embodiments, during the skin reinforcement step, a lattice structure is added between the skin mesh reinforcements to reinforce the structure. The lattice structure is a face-centered cubic or body-centered cubic lattice structure based on the support column.

[0059] In this embodiment, face-centered cubic (FCC) or body-centered cubic (BCC) lattice structures based on struts are added to reinforce the spaces between the skin mesh reinforcements. The FCC lattice structure, due to its high coordination number (12 connection points), exhibits more uniform load distribution and better compressive strength than traditional stiffened plate structures. The BCC structure, through rounded corner node reinforcement design, can improve yield stress. Furthermore, the porosity of the lattice structure is controllable, resulting in weight reduction compared to solid structures while maintaining the same performance, meeting lightweight design requirements. Further, the alternating stacking design of FCC / BCC allows for programmable local mechanical response through asynchronous deformation, avoiding material redundancy. In terms of technical application, SLM technology can precisely form complex lattices.

[0060] In some embodiments, the unit cell diameter of the face-centered cubic or body-centered cubic lattice structure is set to 2 mm to 6 mm, and the rod diameter is 0.5 mm to 2 mm.

[0061] In this embodiment, the unit cell diameter of the face-centered cubic or body-centered cubic lattice structure 700 is set to 2mm to 6mm, and the rod diameter is 0.5mm to 2mm. The 12 coordination number of FCC makes the stress distribution more uniform. The compressive strength is relatively high when the unit cell is 2mm and the rod diameter is 1.5mm. When the rod diameter is less than 0.5mm, microscopic pore defects will reduce fatigue performance. Among them, the yield stress increases with the decrease of unit cell size when the rod diameter is 1-2mm, and the structural stability is optimal when the rod diameter is 2mm and the unit cell is 4mm.

[0062] In some embodiments, in the step of adding the allowance, the preset allowance is set to add 5mm allowance to the contact surface between the optomechanical structure and the substrate 200, 2mm allowance to the mounting hole 300 of the vertical frame, and 2mm allowance to the mounting surface 400 of the top frame.

[0063] In this embodiment, the 5mm allowance on the contact surface (lower end 600) of the substrate 200 can effectively eliminate the shape and position errors of the blank surface and avoid assembly failure due to thermal deformation. The 2mm allowance on the assembly hole 300 of the vertical frame and the assembly surface 400 of the top frame can reduce the amount of machining, reduce the risk of thermal deformation, and ensure the fitting accuracy between the hole 300 and the positioning element.

[0064] In some embodiments, the solid support is configured to add a solid columnar support 501 to the top of the circular hole in the upright frame, and to add block-shaped supports to the lower surface of the top frame suspension structure and the top of the upright frame.

[0065] In this embodiment, a solid columnar support 501 is added to the top of the circular hole in the frame, and block supports are added to the lower surface of the top frame cantilever structure and the top of the frame. The solid columnar support 501 disperses the concentrated stress at the circular hole in the frame through axial bearing, which can reduce the risk of deformation of the thin-walled structure. The block supports form surface contact with the cantilever structure, which improves the support stiffness compared to line contact. In terms of vibration suppression, the distributed layout of the block supports can effectively attenuate high-frequency vibrations, and combined with the axial constraint of the columnar supports, it can improve the natural frequency of the system.

[0066] In some embodiments, during the SLM forming step, the data packet setting parameters of the block support are: laser power of 300W to 400W, scanning speed of 1000mm / s to 1600mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

[0067] In this embodiment, the laser power is 300W to 400W, with a spot diameter of 0.065-0.1mm, achieving an energy density of 5×10⁻⁶. 6 W / cm 2The above methods achieve complete melting of the metal powder, resulting in a support structure density >99.5%. A scanning interval of 0.08mm to 0.14mm (the diameter of the laser spot) ensures a 30%-50% overlap in the melt channels, effectively eliminating incomplete fusion defects. Regarding surface roughness control, a high-speed scan of 1000mm / s to 1600mm / s combined with a thin powder layer of 0.06mm to 0.08mm reduces the surface roughness of the support to below Ra 6.3μm, effectively reducing post-processing difficulties. Specifically, the combination of 400W power and a 1600mm / s speed significantly shortens the single-layer forming time, while the 0.08mm scanning interval avoids efficiency losses caused by repeated melting, and the 0.06mm thin powder layer reduces the number of laser scans per layer, improving overall printing speed.

[0068] In some embodiments, during the SLM forming step, the data packet parameters are: laser power of 300W to 400W, scanning speed of 800mm / s to 1000mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

[0069] In some embodiments, the annealing stress-relief treatment temperature is set to 530°C to 550°C, and the holding time is 1 to 2 hours; the solution heat treatment temperature is set to 830°C to 860°C, and the holding time is 0.5 to 1 hour; the tempering treatment temperature is set to 305°C to 325°C, and the holding time is 1 to 4 hours; the stabilization treatment temperature is set to 85°C to 105°C, and the holding time is 48 to 50 hours; the vacuum degree of the annealing stress-relief treatment, the solution heat treatment, the tempering treatment, and the stabilization treatment is 10. -3 Up to 10 - 2 Pa.

[0070] In this embodiment, medium-temperature annealing at 530°C to 550°C can eliminate 80%-90% of residual stress while avoiding grain coarsening caused by excessively high temperatures. (Combined with 10...) -3 A vacuum environment at Pa levels prevents oxidation and promotes hydrogen escape, reducing the risk of cold cracking. A solution temperature of 830℃ to 860℃ fully dissolves the strengthening phase, obtaining a supersaturated solid solution that improves the material's plasticity and corrosion resistance. Low-temperature tempering at 305℃ to 325℃ retains material strength while increasing hardness and tensile strength. Furthermore, vacuum conditions suppress temper brittleness, resulting in an impact toughness loss of less than 15%. Prolonged holding at 85℃ to 105℃ promotes the transformation of retained austenite into martensite, reducing dimensional changes during service and improving dimensional stability. A vacuum level of 10⁻³ to 10⁻² Pa eliminates the surface oxide layer, enhancing the interfacial bonding strength of subsequent treatments.

[0071] Specific parameter examples of this method:

[0072] Part model preprocessing involves redesigning the part structure, redesigning the lightweight structure, adding margins and solid supports in the 3D model processing software UG, exporting the part in STL format, repairing and arranging the part in Magics software, slicing the part, and generating a forming program.

[0073] Open the low-expansion alloy part in the 3D model processing software UG and perform structural analysis;

[0074] The additive manufacturing process of the mesh reinforcement was redesigned using the 3D model processing software UG, so that the angle between the mesh reinforcement structure distributed on the outer contour of the optomechanical structure and the horizontal direction is greater than or equal to 45°, and a 3D model of the low expansion alloy part structure was established; in order to achieve lightweight, the mesh reinforcement wall thickness was designed to be 2mm and the mesh reinforcement wall height was designed to be 70mm.

[0075] The optical-mechanical structure was designed for lightweighting and skin reinforcement using the 3D modeling software UG, with a skin thickness of 1mm. A lattice structure was added between the skin mesh reinforcements using lattice design software, with face-centered cubic and / or body-centered cubic lattice structures, a unit cell diameter of 6mm, and a rod diameter of 1mm.

[0076] The forming direction of low expansion alloy parts is selected using Magics software to achieve near-net-shape forming of the top frame of the part. The direction perpendicular to the horizontal base plate of the part's vertical frame is the SLM forming direction.

[0077] The optical-mechanical structure margin addition scheme was designed using the 3D model processing software UG. A 5mm margin was added to the contact surface between the optical-mechanical structure and the substrate 200, a 2mm margin was added to the round holes of the vertical frame assembly, and a 1mm margin was added to the top frame assembly surface.

[0078] The solid support structure of the optomechanical structure was designed using the 3D modeling software UG. The solid support consists of a beveled edge design around the top frame, forming a self-supporting, angled structure. Specifically, solid sheet-like supports are added to the outline within the top frame, with beveled corners extending to the inner wall of the vertical frame at an angle greater than or equal to 45° to the horizontal. A small number of solid columnar supports, 1mm in diameter, are added to the top of the circular holes in the vertical frame. Block-like supports are also added to the lower surface of the top frame's overhanging structure and the top of the vertical frame using the Magics software.

[0079] Simuact Additive software was used to perform simulation analysis of the optomechanical structure forming process; the SLM forming process of the designed parts was simulated to obtain its residual stress and deformation law. For positions where the local deformation exceeded ±1mm, external support or compensation allowance was added to control the deformation. A new printing model was established and simulation analysis was performed again. Through continuous iteration, the deformation was controlled to below ±1mm, thus obtaining the optimal SLM forming three-dimensional model.

[0080] The optical-mechanical structure 3D model is sliced ​​using the Magics software. The optimal SLM forming 3D model is then sliced ​​to obtain a data packet that can be recognized by the SLM forming equipment.

[0081] The metal SLM forming equipment is loaded with low-expansion alloy 4J32 powder, a mounting substrate, and a scraper. 4J32 powder with a particle size of 15–53 μm is used, and a wear-resistant plastic material scraper is employed. The 4J32 powder is dried in a vacuum drying oven at 80°C for 6 hours.

[0082] Install the scraper and substrate: Lower the forming platform to a certain height, then move the scraper above the platform. The equipment uses a rubber scraper. Remove the scraper to check the extent of damage and replace it with a new one if necessary. Install the substrate and make initial position adjustments. Initially install the scraper onto the tool holder, lightly tighten the set screw to fix the scraper on the tool holder, and move the forming platform until the substrate surface is flush with the bottom of the forming chamber. Move the scraper above the platform, loosen the set screw to allow the scraper to fall freely, then raise the platform by 5mm and tighten the set screw in sequence from the inside out. After confirming that the powder collection bin is installed and the valve is open, perform the powder spreading operation. Adjust the powder feeding rate to 7 levels, and fine-tune the substrate position based on the powder spreading effect until the substrate outline can be seen through the powder layer. After the substrate position is determined, use a special IPA and lens cleaning paper to clean the laser incident protective lens in a spiral motion from the inside out. Close the forming chamber door, turn on the platform heating, and perform forming chamber air purging.

[0083] SLM forming: When the oxygen content in the forming chamber is reduced to below 200ppm, the required process data package includes laser power, scanning speed, spot diameter, powder thickness, and scanning spacing. Specifically, the parameters for parts and solid supports are: laser power 390W, scanning speed 950mm / s, spot diameter 0.085mm, powder thickness 0.06mm, and scanning spacing 0.012mm. The parameters for block supports are: laser power 350W, scanning speed 1260mm / s, spot diameter 0.085mm, powder thickness 0.06mm, and scanning spacing 0.010mm. After forming, the substrate heating is turned off. Under an argon-protected atmosphere, the substrate temperature is allowed to cool naturally to room temperature. The forming chamber is then opened, and an explosion-proof vacuum cleaner is used to clean the powder from the chamber walls. After cleaning, the powder in the equipment is separated into primary and secondary recycled powder. Specifically, the first-level powder is the powder that has not yet been used in the powder feeding hopper; the second-level powder is the powder adhering to the forming hopper, the powder receiving hopper, the cavity of the part, and its surface; the forming hopper is lowered to the lowest point, and the forming hopper is moved to the powder cleaning and part removal area. The powder material in the forming hopper is taken out, and the screws on the substrate are unscrewed in a diagonal sequence. The substrate with the part is removed and placed on the moving cart platform. Finally, the equipment is further cleaned using a vacuum cleaner.

[0084] After vacuum heat treatment, following the completion of SLM forming of the optomechanical structure, the structure first undergoes stress-relieving annealing at 550℃ for 2 hours; followed by solution heat treatment at 845℃ for 1 hour, and tempering at 325℃ for 2 hours; finally, stabilization treatment is performed at 95℃ for 48 hours; the vacuum degree is 10 throughout the process. -3 ~10 -2 Pa.

[0085] The parts are separated from the substrate using wire cutting; the supports are removed using special tools; and the parts are sandblasted using water blowing equipment. This process ensures cleanliness and guarantees linear expansion performance, resulting in a high-efficiency, low-cost SLM forming of a low-expansion optomechanical structure.

[0086] In this disclosure, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise expressly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0087] In the description of this disclosure, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0088] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0089] The above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for manufacturing a lightweight and highly clean low-expansion alloy optomechanical structure, characterized in that, include: Structural analysis includes static simulation analysis of the optomechanical structure, which includes equivalent stress, strain, and safety factor. Additive manufacturing is used to create a three-dimensional model of the optical-mechanical structure. Skin reinforcement: Skin is added to the outer contour of the optical-mechanical structure; The forming direction is the direction perpendicular to the horizontal substrate of the vertical frame of the optomechanical structure; The allowance is added by adding a preset allowance to the contact surface between the optomechanical structure and the substrate, the assembly holes of the vertical frame, and the assembly surface of the top frame; Solid supports are installed within the top frame of the optomechanical structure to add contour-based solid supports. Simulation analysis is performed on the SLM forming process of the optomechanical structure to obtain its residual stress and deformation law. The deformation is controlled within a preset range to obtain a three-dimensional model of SLM forming. Based on the three-dimensional model of SLM forming, the data packets that the SLM forming equipment can recognize are determined. SLM forming, the data package includes laser power, scanning speed, spot diameter, powder thickness and scanning spacing; After the SLM forming of the optomechanical structure is completed, it undergoes vacuum heat treatment, followed by annealing stress relief treatment, solution heat treatment, tempering treatment, stabilization treatment, and post-treatment.

2. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, The thickness of the mesh reinforcement wall of the optomechanical structure is set to 2mm to 3mm, and the height of the mesh reinforcement wall is set to 70mm to 100mm.

3. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, In the skin reinforcement step, the added skin thickness is set to 1 mm to 2 mm.

4. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, In the skin reinforcement step, a lattice structure is added between the skin mesh reinforcements to strengthen the structure. The lattice structure is a face-centered cubic or body-centered cubic lattice structure based on the support column.

5. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 4, characterized in that, The unit cell diameter of the face-centered cubic or body-centered cubic lattice structure is set to 2 mm to 6 mm, and the rod diameter is set to 0.5 mm to 2 mm.

6. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, In the step of adding the allowance, the preset allowance is set to add 5mm allowance to the contact surface between the optomechanical structure and the substrate, 2mm allowance to the round hole of the vertical frame assembly, and 2mm allowance to the top frame assembly surface.

7. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, The solid support is configured by adding solid column-shaped supports to the top of the circular holes in the vertical frame, and adding block-shaped supports to the lower surface of the top frame cantilever structure and the top of the vertical frame.

8. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 7, characterized in that, In the SLM forming step, the data packet setting parameters of the block support are: laser power of 300W to 400W, scanning speed of 1000mm / s to 1600mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

9. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, In the SLM forming step, the data packet parameters are: laser power of 300W to 400W, scanning speed of 800mm / s to 1000mm / s, spot diameter of 0.065mm to 0.1mm, powder thickness of 0.06mm to 0.08mm, and scanning spacing of 0.08mm to 0.14mm.

10. The manufacturing method for the lightweight and high-cleanliness low-expansion alloy optomechanical structure according to claim 1, characterized in that, The annealing stress relief treatment temperature is set to 530℃ to 550℃, and the holding time is 1 to 2 hours; the solution heat treatment temperature is set to 830℃ to 860℃, and the holding time is 0.5 to 1 hour; the tempering treatment temperature is set to 305℃ to 325℃, and the holding time is 1 to 4 hours; the stabilization treatment temperature is set to 85℃ to 105℃, and the holding time is 48 to 50 hours; the vacuum degree of the annealing stress relief treatment, the solution heat treatment, the tempering treatment, and the stabilization treatment is 10⁻³ to 10⁻² Pa.

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