Blue light desktop type metal 3D printing equipment and self-adaptive forming process

Abstract

The invention discloses blue light desktop type metal 3D printing equipment and a self-adaptive forming process, belongs to the technical field of metal additive manufacturing (LPBF), and is particularly suitable for low-cost rapid manufacturing of consumption-level desktop scenes, small and medium-sized unmanned aerial vehicles and metal structural parts with smart hands. In order to solve the problems that an existing industrial-grade LPBF device is high in cost, low in material reuse rate, high in operation threshold and incapable of adapting to a family desktop scene, the invention provides an equipment scheme of a fixed-focus blue light annular light spot light path, a split type forming bin, constant-pressure atmosphere protection, fully-closed powder recycling and reuse and AI self-adaptive control. And matched material preparation, atmosphere pre-replacement, annular light spot double-area scanning, large-suspension support-free forming, AI closed-loop control and low-threshold post-treatment processes are adopted. The comprehensive mass production cost of the equipment is smaller than or equal to 4.5 thousand yuan, the powder utilization rate is larger than or equal to 90%, the density of a formed part is larger than or equal to 99.2%, the mechanical property reaches the forging standard, full-process one-button operation can be achieved, the equipment is completely suitable for being used on a family table top, and the forming and using requirements of small and medium-sized unmanned aerial vehicles and intelligent hand parts with bodies are met.

Description

[0001] This invention belongs to the field of metal additive manufacturing technology, specifically involving laser powder bed fusion (LPBF) forming technology, with IPC classification numbers B22F 10 / 28; B33Y 10 / 00; B33Y 30 / 00. It is particularly suitable for low-cost and rapid manufacturing of metal structural components for consumer desktop scenarios, small and medium-sized drones, and smart hands. Background Technology

[0002] Laser powder bed fusion (LPBF) has become a core technology for additive manufacturing of high-end metal parts due to its advantages of high forming precision, high degree of freedom in structural design, and ability to achieve integrated forming of complex topologies. Currently, mature commercial solutions and core patent portfolios for this technology are concentrated in high-value-added industrial scenarios such as aerospace, medical, and industrial mold making. Equipment prices are generally above 500,000 RMB, and the core technologies revolve around industrial-grade requirements such as high-power multi-laser systems, dynamic focusing optical paths, and high-precision circulating atmosphere control, without systematic adaptation for consumer desktop applications.

[0003] Based on literature and patent searches and analysis of existing technologies, the core existing technologies related to metal 3D printing are as follows: The closest to the present invention is **CN118218620A (A Customized Laser Metal 3D Printing Device for Spot Shaping)**, which discloses related laser spot shaping technology, but adopts an industrial-grade multi-laser, multi-channel conical shell architecture, designed only for industrial production scenarios, without miniaturization or low-cost consumer-grade adaptation; **CN119657956A (A Multifunctional Adaptive Laser Metal 3D Printing Equipment and its Control Method)**, disclosed at the same time, focuses on optimizing powder magnetization transport in laser cladding nozzles, also using an industrial-grade equipment architecture, without systematic optimization for home desktop scenarios in terms of size, cost, and operational barriers; while **CN106363920A (A High-Efficiency, High-Mechanical-Performance 3D Printing Device and Method Based on Fused Deposition Modeling)** uses fused deposition modeling, which differs from the laser powder bed melting process of the present invention, requiring specialized post-processing equipment, making it unsuitable for home scenarios to complete the entire molding process.

[0004] In addition, the desktop metal 3D printing solutions already available on the market either simply downgrade and simplify industrial-grade LPBF equipment, which cannot reliably guarantee the density and mechanical properties of the molded parts and cannot meet the load and fatigue resistance requirements of small and medium-sized drone frames and smart hand joints; or they use a binder spraying process, which requires professional debinding and sintering equipment, making them unsuitable for home use.

[0005] Existing technologies generally suffer from three major technical defects, which are also the technical pain points that this invention aims to address: First, the high cost of the equipment prevents its adoption in consumer-grade home environments. The core cost of industrial-grade LPBF equipment is concentrated in the dynamic focusing optical path system, imported high-precision galvanometers, large sealed molding chambers, and high-flow-rate circulating atmosphere systems. The hardware cost of a single unit exceeds 100,000 yuan, far exceeding the purchasing power of home users. Existing miniaturization solutions only reduce size without architectural innovation, failing to balance low cost and molding performance. Furthermore, directly adopting the industrial-grade architecture carries a very high risk of patent infringement.

[0006] Secondly, the high cost of materials and the high operational barriers make it unsuitable for home use. Specialized atomized spherical metal powder is expensive, and the current process has a powder utilization rate of less than 60%. Recycling and reusing the powder requires specialized screening and drying equipment. At the same time, metal powder poses a health risk from inhalation, and continuous inert gas purging poses a safety hazard. Home settings lack the professional protection and operating conditions to use it safely and compliantly.

[0007] Third, the molding capabilities and operational barriers do not match consumer-grade demands. Existing processes require the design of numerous support structures for thin-walled parts in drones and complex joints in smart hands, making post-processing difficult. Debugging process parameters requires a professional technical background, which home users without professional experience cannot operate independently. At the same time, there are common problems such as poor melt pool stability, numerous porosity defects, and substandard mechanical properties, making it impossible to mold parts that meet the requirements of the target application scenarios. Summary of the Invention

[0008] (a) Technical problems to be solved In view of the deficiencies and gaps in the existing technology, the present invention aims to solve the following technical problems: 1. Break through the core patent barriers of industrial-grade equipment, design a brand-new low-cost optical path, molding chamber, and atmosphere system solution, and achieve a reduction of more than 40% in the overall mass production cost of the equipment compared with industrial-grade equipment of the same performance, with the mass production cost controlled within 45,000 yuan.

[0009] 2. Construct a material reuse and safety protection system suitable for home scenarios, reduce the overall cost of powder use by more than 25%, increase the powder utilization rate to more than 90%, and achieve zero dust leakage, full laser protection, and safe gas use during the printing process, meeting the requirements for use in home indoor environments.

[0010] 3. Develop a dedicated molding process for small and medium-sized drones and intelligent hand parts, achieving a critical overhang angle of ≥65° without support, a minimum molding wall thickness of 0.3 mm, a density of ≥99.2% for the molded parts, and mechanical properties that meet forging standards. At the same time, the entire process can be operated with one click and requires no professional technical background.

[0011] 4. Develop novel and innovative independent technical solutions, with all core components sourced from domestic readily available supply chains, enabling low-cost mass production and deployment.

[0012] (II) Technical Solution To achieve the above objectives, the present invention adopts the following technical solution, which corresponds 100% to the claims, and all reference numerals in the drawings are completely matched with those in the drawings: On one hand, the present invention provides a blue light desktop metal 3D printing device, including a laser optical path system, a forming chamber unit, an atmosphere protection unit, and a control unit, characterized in that: The laser optical path system is a fixed-focus blue light ring spot optical path system, including a 445nm blue light semiconductor laser unit (1), a static ring spot shaping unit (2), a fixed focal length focusing unit (3), and a digital galvanometer scanning unit (4) connected sequentially along the optical path. The rated output power of the 445nm blue light semiconductor laser unit (1) is 60W. The absorption rate of 445nm blue light by metal materials is more than 3 times that of 1064nm infrared laser, which can achieve complete melting of metal powder at low power. The power consumption is reduced by 70% compared with the infrared solution, and it is suitable for household 220V power supply environment. The static ring spot shaping unit (2) is a single-piece static shaping lens used to shape the Gaussian beam into a ring spot with an outer ring-inner ring dual energy distribution, which can achieve a stable molten pool with different powder layer thicknesses without dynamic adjustment. The fixed-focal-length focusing unit (3) is a single-piece fixed-focal-length lens with a focal length of 100 mm. The optical path structure has no dynamic focusing moving parts, and the optical path cost is reduced by more than 65% compared with the traditional dynamic focusing scheme. The digital galvanometer scanning unit (4) adopts a domestic low-cost digital galvanometer with a maximum scanning speed of ≥2000 mm / s and a positioning accuracy of ≤±15 μm. With the optical path pre-compensation algorithm, it achieves consistent focusing accuracy throughout the entire forming surface, replacing imported high-priced galvanometers and reducing costs by 70%.

[0013] The forming chamber unit is a split modular structure, including a printing forming module and a powder cleaning and recovery module set separately at the top and bottom. The two are connected by a quick-connect sealing interface. The overall size is ≤400 mm×400 mm×450 mm and the weight is ≤28 kg, which is fully suitable for home desktop use. The printing forming module has a built-in forming cylinder with an effective forming size of 150 mm×150 mm×100 mm, which fully covers the forming needs of small and medium-sized drone frames, motor bases, and full-size parts of smart hands. The forming cylinder lifting platform (7) is driven by a screw lifting drive mechanism (8), with a positioning accuracy of ≤±5 μm. The powder spreading mechanism adopts a powder feeding hopper (5) and a powder spreading scraper (6), with a powder layer thickness adjustment range of 20 μm~100 μm. The excess powder is collected by the excess powder collection inclined plate (9) to the powder cleaning and recovery module. The powder cleaning and recovery module is quickly connected to the printing forming module. After printing, the forming cylinder can be directly lowered to the powder cleaning and recovery module to achieve fully enclosed powder cleaning without dust leakage. The molding chamber adopts a fully enclosed structure to prevent laser radiation. The viewing window uses laser protective glass that complies with GB 7247.1-2012 Safety of Laser Products Part 1: Equipment Classification and Requirements. The chamber is equipped with a door-opening power-off safety interlock device, a pressure abnormality interlock, and a full-band laser protection structure to eliminate safety risks for home use.

[0014] The atmosphere protection unit is a constant-pressure atmosphere protection system, including a staged pre-displacement component and a micro-constant-pressure maintenance component, used to stably control the oxygen content in the forming chamber below 100 ppm. The staged pre-displacement component first evacuates the forming chamber to a negative pressure of -0.02 MPa using a vacuum pump, then fills it with argon gas to a slightly positive pressure. Repeating this process twice reduces the oxygen content to below 100 ppm, eliminating the need for continuous high-flow-rate purging. The micro-constant-pressure maintenance component uses a micro-flow control valve with a range of 0 L / min to 5 L / min, combined with real-time feedback from an oxygen content sensor. It only replenishes a small amount of argon gas when the oxygen content exceeds the limit or the pressure drops, achieving stable atmosphere for long-term printing. A single 40 L bottle of industrial argon gas can support continuous printing for ≥100 hours, reducing argon gas consumption by more than 80% compared to traditional circulation systems. It also includes a gas filtration and purification unit (11), a gas circulation pump (12), and a control and power supply box (10); the gas filtration and purification unit (11) has a built-in HEPA high-efficiency dust filter and an activated carbon adsorption filter, with a dust filtration efficiency of ≥99.97% at the exhaust port, no metal powder leakage, and adsorption of trace amounts of smoke generated during the printing process; the gas circulation pump (12) is linked with the gas filtration and purification unit (11) to realize indoor gas circulation filtration, which is suitable for the home indoor safety environment.

[0015] The Blu-ray desktop metal 3D printing equipment also includes a fully enclosed powder recycling and reuse unit and an AI adaptive control unit.

[0016] The fully enclosed powder recycling and reuse unit is integrated within the powder cleaning and recycling module. It includes an ultrasonic sieving component, a fluidized bed drying and modification component, and an automatic mixing and conveying component connected in sequence. This unit enables the fully enclosed recycling, modification, and reuse of residual printing powder. The ultrasonic sieving component uses a 300-mesh ultrasonic vibrating screen to automatically remove large splatter particles and agglomerated powder generated during printing, ensuring a stable particle size distribution of the reused powder between 15 μm and 53 μm. The fluidized bed drying and modification component has a built-in fluidized bed low-temperature drying chamber. It performs 120℃ vacuum drying and micro-fluidized bed modification on the sieved recycled powder, removing adsorbed moisture and trace oxide layers from the powder surface. Simultaneously, it adds 0.2% (mass fraction) of nano-silica flow aid to ensure the recycled powder's flowability is consistent with that of new powder. The automatic mixing and conveying component automatically mixes the treated recycled powder with new powder at a 3:7 mass ratio and directly conveys it to the powder spreading system without manual intervention. The entire process is enclosed and dust-free.

[0017] The AI ​​adaptive control unit incorporates a lightweight edge AI inference model and a visual monitoring module, integrated within the control and power supply box (10), and enables human-computer interaction via a touch control panel (13). The control and power supply box (10) integrates an industrial-grade ARM control motherboard and a touch control panel (13), which is a 7-inch touchscreen. The AI ​​adaptive control unit incorporates a material-process database, covering full parameter packages for all compatible materials such as 316L stainless steel and AlSi10Mg aluminum alloy. It also incorporates dedicated molding process packages for small and medium-sized UAVs and intelligent hand parts. After the user imports the model, the system automatically matches the optimal process parameters and support scheme, enabling one-click printing. The visual monitoring module is used to collect real-time data on melt pool brightness, powder spreading quality, and interlayer forming status. The lightweight end-side AI inference model is used to dynamically adjust laser power and scanning speed based on the collected data, automatically compensating for the effects of changes in ambient temperature and humidity to ensure a stable and defect-free printing process. At the same time, it has a built-in abnormal shutdown protection mechanism that automatically pauses printing and sends a notification for issues such as abnormal powder spreading, excessive melt pool splashing, and excessive oxygen content, which can be easily handled by home users.

[0018] Furthermore, the lightweight edge AI inference model adopts a lightweight detection model based on YOLOv8n optimization. The input is a real-time image of the molten pool and powder spreading, and the output is compensation parameters for laser power and scanning speed. The model parameter count is ≤2 M, which can run in real time on the ARM Cortex-A76 motherboard. The inference speed is ≥30 fps, which fully meets the real-time control requirements of the edge.

[0019] On the other hand, the present invention provides an adaptive forming process for Blu-ray desktop metal 3D printing, using the Blu-ray desktop metal 3D printing equipment described in any of the above claims, the process comprising the following steps: S1 Material Preparation: 316L stainless steel atomized spherical virgin powder and modified recycled powder are uniformly mixed at a mass ratio of 7:3 to obtain a mixed powder for printing. The preparation process of the modified recycled powder is as follows: printing residue is sieved through a 300-mesh ultrasonic sieve, dried in a vacuum environment at 120℃ for 2 h, and 0.2% by mass of nano-silica flow aid is added. The mixture is then uniformly mixed by argon gas atomization. The loose density of the mixed powder is ≥4.2 g / cm³, and the Hall flow rate is ≤28 s / 50 g, which is consistent with the performance of the virgin powder.

[0020] S2 Atmosphere Pre-replacement: A staged extraction-filling replacement method is adopted to reduce the oxygen content in the molding chamber to below 100 ppm and maintain a 500 Pa argon micro-positive pressure atmosphere.

[0021] S3 Annular Spot Dual-Zone Scanning Molding: A 445 nm annular spot blue laser is used for layer-by-layer printing with a 67° interlayer rotation orthogonal scanning strategy. The outer ring laser power accounts for 60% of the total power and is used for powder bed preheating, reducing the cooling rate of the melt pool and minimizing thermal stress and cracking risk. The inner ring laser power accounts for 40% of the total power and is used for complete powder melting to ensure the density of the molded part. The printing process parameters are as follows: laser power 45 W~55 W, scanning speed 800 mm / s~1200 mm / s, powder layer thickness 25 μm~40 μm, and scanning line spacing 40 μm~50 μm.

[0022] S4 Large Overhang Unsupported Adaptive Molding: For structures with an overhang angle ≥65°, it adopts gradient process parameters such as reduced power, reduced scanning speed, and reduced powder layer thickness to achieve unsupported molding, with a critical overhang angle ≥65°; for structures with an overhang angle of 45°~65°, it adopts a point-like easy-to-peel support design, which reduces the support volume by more than 70% compared to traditional solutions and can be easily removed manually; it has a built-in support strategy library for drones and intelligent hand parts, and automatically identifies the structure and generates the optimal support solution after the user imports the model.

[0023] S5 Real-time Closed-Loop Control: The visual monitoring module collects real-time data on melt pool brightness, powder spreading status, and interlayer forming quality. The end-side AI model dynamically adjusts process parameters to achieve adaptive and stable control of the printing process.

[0024] S6 Fully Enclosed Low-Threshold Post-Processing: After printing, residual powder is cleaned in the enclosed forming chamber, and easily peelable supports are removed manually. For parts with high mechanical performance requirements, a household oven can be used for low-temperature stress relief annealing at 300℃ for 2 hours, without the need for professional heat treatment equipment, to obtain the final metal forming parts.

[0025] (III) Beneficial Effects Compared with the closest prior art, this invention brings the following significant, repeatable, and quantifiable beneficial technical effects, with each technical feature corresponding one-to-one with the beneficial effect, fully supporting the inventiveness: 1. Significantly reduced costs, suitable for the consumer market: By replacing the traditional dynamic focusing optical path with a fixed-focus blue light ring spot optical path, replacing imported galvanometers with domestically produced ones, and replacing the high-flow circulation system with a micro-volume constant pressure atmosphere system, the overall cost of mass production of the equipment is ≤45,000 yuan, which is more than 40% lower than that of industrial-grade equipment with the same performance; through a fully enclosed powder recycling and reuse system, the overall cost of powder use is reduced by more than 25%, and the powder utilization rate is increased from the traditional 60% to more than 90%; argon consumption is reduced by more than 80%, and the overall cost per print is reduced by more than 45%, making it suitable for the purchasing power of home users.

[0026] 2. Excellent forming performance, meeting the requirements of target scenarios: Through dual-energy annular light spot optical path + AI closed-loop control, the density of 316L stainless steel forming parts is ≥99.2%, and can reach up to 99.8%; the room temperature tensile strength is ≥560 MPa, and the elongation after fracture is ≥45%, which meets the forging standard; the minimum forming wall thickness is 0.3 mm, and the critical overhang angle without support is ≥65°, which fully meets the forming and use requirements of small and medium-sized drones and intelligent hand parts.

[0027] 3. Significantly improved printing efficiency and stability: Compared with the traditional Gaussian beam infrared LPBF process of the same power, the printing efficiency is improved by more than 20%, and the printing time of a standard 10 mm × 10 mm × 10 mm cube specimen is ≤12 minutes; through AI adaptive closed-loop control, it can achieve more than 200 hours of unattended stable printing, and the molding defect rate is reduced by more than 80%.

[0028] 4. Highly adaptable to home environments and safe and compliant: The device's overall dimensions are ≤400 mm×400 mm×450 mm, and its weight is ≤28 kg, making it suitable for placement on home desktops; the operating noise is ≤38 dB, with no dust leakage and no harmful gas emissions, complying with national standards for household electrical safety and laser safety; the entire process is operated with one button, requiring no professional technical background, and home users can easily get started. Attached Figure Description

[0029] This manual includes two accompanying drawings. All reference numerals match the content of the drawings 100% accurately. There are no reference numerals not shown in the drawings, and no reference numerals are not represented in the drawings. Figure 1 This is a schematic diagram of the overall structure of the blue light desktop metal 3D printing device described in this invention; Figure 2 This is a schematic diagram of the core structure of the fixed-focus blue light ring spot optical path system described in this invention.

[0030] Explanation of reference numerals in the attached figures: Figure 1 In the middle: 1-445nm blue semiconductor laser unit; 2-static annular spot shaping unit; 3-fixed focal length focusing unit; 4-digital galvanometer scanning unit; 5-powder feeding hopper; 6-powder spreading scraper; 7-forming cylinder lifting platform; 8-screw lifting drive mechanism; 9-residual powder collection inclined plate; 10-control and power supply box; 11-gas filtration and purification unit; 12-gas circulation pump; 13-touch control panel.

[0031] Figure 2 In the middle: 1-445nm blue semiconductor laser unit; 2-static ring spot shaping unit; 3-fixed focal length focusing unit; 4-digital galvanometer scanning unit. Detailed Implementation

[0032] The present invention will be further described in detail below with reference to specific embodiments and comparative examples. The following embodiments are only used to clearly illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Those skilled in the art can reproduce all the technical solutions of the present invention without creative effort based on the content disclosed in the specification, and understand its beneficial effects.

[0033] Example 1: Implementation of Small and Medium-Sized Unmanned Aerial Vehicle (UAV) Frame Molding This embodiment uses the blue light desktop metal 3D printing equipment described in this invention to form the frame parts of a quadcopter drone. The specific implementation process is as follows: 1. Basic parameters of the equipment: The equipment adopts a 445 nm blue semiconductor laser unit (1) with a rated output power of 60 W, a fixed focal length focusing unit (3) with a focal length of 100 mm, a domestic digital galvanometer scanning unit (4) with a maximum scanning speed of 2000 mm / s and a positioning accuracy of ±15 μm; the effective forming size of the forming cylinder is 150 mm × 150 mm × 100 mm, the overall size of the machine is 400 mm × 400 mm × 450 mm, and the weight of the machine is 26 kg.

[0034] 2. Material preparation: Domestically produced gas-atomized 316L stainless steel spherical powder with a particle size of 15 μm to 53 μm and D50 = 32 μm was used. The recycled powder was ultrasonically sieved through a 300-mesh screen, vacuum dried at 120℃ for 2 h, and modified by adding 0.2% (mass fraction) nano-silica. The recycled powder was then mixed with the new powder at a mass ratio of 3:7 to obtain the mixed powder for printing. The Hall flow rate of the mixed powder was 26 s / 50 g, and the loose packing density was 4.3 g / cm³.

[0035] 3. Atmosphere pre-replacement: Two stages of evacuation-filling replacement cycle are adopted to reduce the oxygen content in the molding chamber to 82 ppm and maintain a slight positive pressure of 500 Pa argon gas.

[0036] 4. Molding process parameters: For thin-walled drone frames (minimum wall thickness 0.6 mm), a laser power of 48 W, a scanning speed of 900 mm / s, a powder layer thickness of 30 μm, a scanning line spacing of 40 μm, and 67° interlayer rotational orthogonal scanning are used; for structures with a hanging angle ≥65°, gradient process parameters are used for unsupported molding without adding additional supports.

[0037] 5. Printing process: The visual monitoring module of the AI ​​adaptive control unit collects the brightness of the molten pool and the powder spreading status in real time. The AI ​​model on the end dynamically adjusts the laser power and scanning speed in real time. The whole process is unattended, and the total printing time is 4 hours and 12 minutes.

[0038] 6. Post-processing: After printing, residual powder is cleaned in the closed molding chamber. In this embodiment, a supportless molding scheme is adopted, which does not require the removal of supports. The final molded part is obtained by directly using a household oven at 300℃ for 2 hours for low-temperature stress relief annealing.

[0039] The third-party testing results of the molded parts in this embodiment are as follows: density 99.5%, room temperature tensile strength 572 MPa, yield strength 248 MPa, elongation after fracture 48%, dimensional accuracy ±0.08 mm within 100 mm, and surface roughness Ra=4.2 μm, which fully meet the requirements of UAV flight load and lightweighting.

[0040] Example 2: Implementation of Embossed Intelligent Hand Joint Molding This embodiment uses the equipment and process described in this invention to mold a bionic joint part for a smart hand. The specific implementation process is as follows: 1. Equipment and material parameters: completely consistent with Example 1.

[0041] 2. Atmosphere pre-replacement: Through two stages of evacuation and refilling, the oxygen content in the molding chamber is reduced to 76 ppm, maintaining a slight positive pressure of 500 Pa argon gas.

[0042] 3. Molding process parameters: For complex curved surfaces and multiple overhang structures of joint parts, a laser power of 50 W, a scanning speed of 1000 mm / s, a powder layer thickness of 30 μm, a scanning line spacing of 45 μm, and a 67° interlayer rotation orthogonal scanning are used; for overhang structures of 45° to 65°, a point-like easy-peel support design is adopted, which reduces the support volume by 72% compared with the traditional rectangular support solution.

[0043] 4. Printing process: AI adaptive closed-loop control, unattended operation throughout, total printing time 2 hours and 35 minutes.

[0044] 5. Post-processing: Clean up excess powder in the closed molding chamber, and manually remove the easily peelable supports with needle-nose pliers. No additional polishing is required to obtain the final molded part.

[0045] The third-party testing results of the molded part in this embodiment are as follows: density 99.4%, room temperature tensile strength 568 MPa, elongation after fracture 46%, minimum molded wall thickness 0.3 mm, dimensional accuracy ±0.07 mm, bending fatigue 10 7 The cycle strength is 180 MPa, which meets the fatigue resistance requirements for reciprocating motion of the intelligent hand joint.

[0046] Comparative Example 1: Comparison of Traditional Infrared LPBF Process This comparative example is the closest existing technical solution, using a 60 W 1064 nm infrared laser of the same power, a traditional Gaussian beam, and a dynamic focusing optical path. The remaining molding materials, part structures, and basic process parameters are completely consistent with Example 1.

[0047] Comparative results: The density of the molded part in this comparative example is 98.2%, the room temperature tensile strength is 510 MPa, and the elongation after fracture is 32%, which are significantly lower than those in Example 1 of this invention; the total printing time is 5 hours and 28 minutes, which is 22% slower than that of this invention; the hardware cost of the optical path system is 3.2 times that of this invention, the continuous printing time of a single bottle of argon is only 18 hours, and the argon consumption is 5.5 times that of this invention.

[0048] Comparison of direct reuse of traditional recycled powder This comparative example uses recycled powder that has not undergone screening, drying, or modification treatment, and mixes it directly with new powder at a mass ratio of 3:7. The rest of the equipment, processes, and parts structure are completely consistent with Example 1.

[0049] Comparative results: The Hall flow rate of the mixed powder in this comparative example was 38 s / 50 g, which significantly reduced the flowability, resulting in uneven powder distribution and local powder shortages and accumulations. The density of the molded parts was 96.8%, with a large number of pore defects. The room temperature tensile strength was 420 MPa, and the elongation after fracture was 18%, which could not meet the requirements for the use of structural parts.

[0050] By comparing the above embodiments with comparative examples, the significant technical effects brought about by the technical solution of the present invention can be clearly verified. Any non-substantial modifications and substitutions made to the solution by those skilled in the art without departing from the core concept of the present invention are all within the protection scope of the present invention.

Claims

1. A blue light desktop metal 3D printing device, comprising a laser optical path system, a forming chamber unit, an atmosphere protection unit, and a control unit, characterized in that: The laser optical path system is a fixed-focus blue light ring spot optical path system, including a 445nm blue light semiconductor laser unit (1), a static ring spot shaping unit (2), a fixed focal length focusing unit (3), and a digital galvanometer scanning unit (4) connected sequentially along the optical path; the static ring spot shaping unit (2) is a single-piece static shaping lens used to shape the Gaussian beam into a ring spot with an outer ring-inner ring dual energy distribution; the fixed focal length focusing unit (3) is a single-piece fixed focal length lens, and the laser optical path system has no dynamic focusing moving parts throughout the entire process; The molding chamber unit is a split modular structure, including a printing molding module and a powder cleaning and recovery module set separately at the top and bottom. The printing molding module and the powder cleaning and recovery module are connected through a quick-connect sealing interface. The atmosphere protection unit is a constant pressure atmosphere protection system, including a graded pre-replacement component and a micro constant pressure maintenance component, used to stably control the oxygen content in the molding chamber to below 100ppm. The blue light desktop metal 3D printing equipment also includes a fully enclosed powder recycling and reuse unit and an AI adaptive control unit; The fully enclosed powder recycling and reuse unit is integrated into the powder cleaning and recycling module, including an ultrasonic sieving component, a fluidized drying and modification component, and an automatic mixing and conveying component connected in sequence, for realizing fully enclosed recycling, modification and reuse of printing residue powder; The AI ​​adaptive control unit incorporates a lightweight edge AI inference model and a visual monitoring module. The visual monitoring module is used to collect the molten pool status and powder spreading quality in real time, while the AI ​​inference model is used to dynamically adjust the laser power and scanning speed based on the collected results.

2. The blue light desktop metal 3D printing device according to claim 1, characterized in that, The rated output power of the 445nm blue semiconductor laser unit (1) is 60W, the focal length of the fixed focal length focusing unit (3) is 100mm, the maximum scanning speed of the digital galvanometer scanning unit (4) is ≥2000mm / s, and the positioning accuracy is ≤±15μm.

3. The blue light desktop metal 3D printing device according to claim 1, characterized in that, The printing molding module has a built-in molding cylinder with an effective molding size of 150mm×150mm×100mm. The molding cylinder lifting platform (7) is driven by a screw lifting drive mechanism (8), with a positioning accuracy of ≤±5μm. The overall dimensions of the equipment are ≤400mm×400mm×450mm, and the weight of the whole machine is ≤28kg.

4. The blue light desktop metal 3D printing device according to claim 1, characterized in that, The graded pre-replacement component reduces the oxygen content in the molding chamber to below 100ppm through at least two evacuation-filling replacement cycles; the micro-constant pressure maintenance component uses a micro-flow control valve with a range of 0~5L / min in conjunction with an oxygen content sensor for real-time feedback, and the argon consumption is reduced by more than 80% compared with the traditional circulating atmosphere system of the same specifications.

5. The blue light desktop metal 3D printing device according to claim 1, characterized in that, The molding chamber is equipped with a door-opening power-off safety interlock device and a full-band laser protection structure.

6. The blue light desktop metal 3D printing device according to claim 1, characterized in that, It also includes a gas filtration and purification unit (11), a gas circulation pump (12), and a control and power supply box (10); the gas filtration and purification unit (11) has a built-in HEPA high-efficiency dust filter and an activated carbon adsorption filter, with a dust filtration efficiency of ≥99.97% at the exhaust port; the control and power supply box (10) integrates an industrial-grade control motherboard and a touch control panel (13), the touch control panel (13) being a 7-inch touch screen.

7. The blue light desktop metal 3D printing device according to claim 1, characterized in that, The AI ​​adaptive control unit incorporates a dedicated molding process package for small and medium-sized drones and intelligent hand parts, which automatically matches process parameters and support schemes after the user imports the model, enabling one-click printing; the visual monitoring module collects the brightness of the molten pool and the powder spreading quality in real time, and dynamically adjusts the laser power and scanning speed through the AI ​​inference model to achieve stable unattended printing for more than 200 hours.

8. A blue light desktop metal 3D printing adaptive forming process, characterized in that, Using the Blu-ray desktop metal 3D printing equipment as described in any one of claims 1 to 7, the process includes the following steps: S1 Material Preparation: 316L stainless steel atomized spherical new powder and modified recycled powder are uniformly mixed at a mass ratio of 7:3 to obtain a mixed powder for printing. The Hall flow rate of the mixed powder is ≤28s / 50g. S2 Atmosphere Pre-replacement: A staged extraction-filling replacement method is adopted to reduce the oxygen content in the molding chamber to below 100ppm and maintain a 500Pa argon micro-positive pressure atmosphere. S3 Annular Spot Dual-Zone Scanning Molding: A 445nm annular spot blue laser is used to print layer by layer with a 67° interlayer rotation orthogonal scanning strategy. The outer ring laser power accounts for 60% for powder bed preheating, while the inner ring laser power accounts for 40% for complete powder melting. S4 Large Overhang Unsupported Adaptive Molding: For structures with an overhang angle ≥65°, a gradient process parameter of reduced power, reduced scanning speed, and reduced powder layer thickness is adopted to achieve unsupported molding; for structures with an overhang angle of 45°~65°, a point-like easy-peel support design is adopted, which reduces the support volume by more than 70% compared with the traditional support solution. S5 Real-time Closed-Loop Control: The visual monitoring module collects the brightness of the molten pool, powder spreading status and interlayer forming quality in real time, and dynamically adjusts the laser power and scanning speed through the end-side AI inference model to achieve adaptive and stable control of the printing process; S6 Fully enclosed post-processing: After printing, the residual powder in the forming cylinder is collected by the residual powder collection inclined plate (9) into the powder cleaning and recovery module. The residual powder is cleaned in the enclosed forming chamber, and the easily peelable support is removed manually to obtain the metal forming part.

9. The adaptive forming process for blue light desktop metal 3D printing according to claim 8, characterized in that, In step S1, the preparation process of the modified recycled powder is as follows: the printing residue powder is sieved through a 300-mesh ultrasonic sieve, dried in a vacuum environment at 120°C for 2 hours, and 0.2% by mass of nano-silica flow aid is added and mixed evenly by argon gas flow.

10. The adaptive forming process for blue light desktop metal 3D printing according to claim 8, characterized in that, In step S3, the printing process parameters are as follows: laser power 45~55W, scanning speed 800~1200mm / s, powder layer thickness 25~40μm, and scanning line spacing 40~50μm.

11. The adaptive forming process for blue light desktop metal 3D printing according to claim 8, characterized in that, In step S6, the resulting 316L stainless steel formed parts have a density ≥99.2%, a room temperature tensile strength ≥560MPa, and an elongation after fracture ≥45%. For parts with high mechanical performance requirements, a low-temperature stress-relieving annealing treatment of 300℃×2h is added after step S6.

12. The adaptive forming process for blue light desktop metal 3D printing according to claim 8, characterized in that, The metal forming parts are small and medium-sized drone frames, motor bases, or intelligent hand joints and finger joints; the minimum forming wall thickness of the drone frame is ≤0.6mm, and the minimum forming wall thickness of the joints and finger joints is ≤0.3mm.

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