Lpbf metal 3d printing method and system based on dynamic regulation of discrete points

Abstract

The application relates to the technical field of metal 3D printing, and discloses an LPBF metal 3D printing method and system based on dynamic regulation and control of discrete points, which decomposes the slice layer contour range of a 3D model into a dot matrix with a set density and uniform distribution of scanning points; laser parameters of each scanning point in the dot matrix are set, including power and exposure time; based on the dot matrix, the scanning sequence of all scanning points is planned as a scanning path; the laser is controlled to scan according to the scanning path, and each scanning point on the scanning path is scanned by using the corresponding laser parameter thereof; the next slice of the 3D model is converted, and the above steps are repeated until the scanning of the entire 3D model is completed. The application converts a conventional one-dimensional vector line scanning path into a zero-dimensional and programmable dot matrix, each scanning point is independently given scanning power and laser exposure time, inertia-free scanning of an arbitrary geometric path and complex features is realized, and the application is suitable for application scenarios such as aerospace lightweight dot matrix structures, medical porous implants and the like.

Description

Technical Field

[0001] This invention relates to the field of metal 3D printing technology, and in particular to an LPBF metal 3D printing method and system based on discrete point dynamic control. Background Technology

[0002] Laser powder bed melting (LPBF) technology, as one of the core processes in the field of metal additive manufacturing, has been widely used in high-end manufacturing fields such as key components of aerospace engines, medical implants, and precision parts of high-end equipment due to its outstanding advantages in high-precision forming and manufacturing of complex geometries.

[0003] Currently, traditional LPBF metal 3D printing generally adopts vector scanning (continuous scanning) technology, the specific technical process of which is as follows: First, the 3D model of the target part is converted into a 2D plane using standard commercial software (such as Magics) (this process is called slicing). Then, it is imported into the 3D printing equipment software, and "vector line filling" is performed on each 2D plane, that is, the 2D plane is converted into a 1D vector line. The form of the vector line can be various, including but not limited to straight lines, broken lines, and curves. Then, process parameters are assigned to these vector lines, mainly laser scanning power (P) and laser scanning speed (v). By adjusting the form of the scanning line and process parameters, the printing quality (thermal stress) and printing efficiency can be managed, but the flexibility and upper limit of management are limited. The specific disadvantages are reflected in four aspects: First, the scanning flexibility is low, and point-level control cannot be achieved. Traditional LPBF uses a vector line scanning mode, and the laser must move along a fixed trajectory, making it impossible to independently control a single molten pool point. Since the scanning path depends on vector line segments, it is difficult to achieve arbitrary order of point rearrangement, resulting in uneven heat accumulation distribution and affecting the forming quality. Second, the energy control precision is insufficient. Energy input depends on laser scanning power (P) and laser scanning speed (v), but changes in scanning speed (v) affect the stability of the molten pool. For example, high-speed scanning may lead to incomplete melting, while low-speed scanning may lead to over-melting. The inability to precisely control the exposure time of each point results in inconsistent local energy input, affecting the uniformity of the microstructure. Furthermore, because vector line scanning involves continuous exposure, thermal interference exists between adjacent molten pools, and the temperature field is continuous, making independent modulation difficult. Third, the problem of thermal stress accumulation is difficult to optimize. Traditional LPBF uses fixed scanning strategies (such as interlayer rotation and partitioned scanning), which, while achieving a more uniform thermal stress distribution to some extent, cannot dynamically adjust the scanning sequence based on the real-time temperature field / temperature gradient. Due to the continuous path, heat accumulation concentrates in certain areas, easily leading to defects such as warping and cracks. Fourth, data processing methods are limited. The layered slice data of traditional LPBF is usually converted into vector line segments (G-code), which cannot directly support rasterized scanning, thus limiting process optimization.

[0004] To address the aforementioned shortcomings of traditional vector scanning processes, an improved LPBF metal 3D printing method based on path thermal balance optimization has been disclosed in the prior art. This improved method assesses high-risk forming areas through a temperature field model and dynamically adjusts laser parameters (power, speed) and scanning paths (vector merging / splitting) to reduce thermal stress. While this method can improve warping and collapse defects, it still has the following limitations: First, the granularity of path optimization is insufficient. It only performs secondary optimization of local paths for "high-risk forming areas," failing to achieve dynamic control at the point-scan level across the entire region. This results in the potential accumulation of temperature gradients in non-high-risk areas, affecting overall forming accuracy. Second, point-scan control is lacking. The vector merging or splitting strategy is based on the traditional vector scanning mode, which cannot achieve precise point-to-point energy matching. Although skip scanning can disperse heat input, it is difficult to cope with thermal field changes in complex geometries. Third, multi-parameter collaborative optimization is insufficient. The adjustment of laser power and speed is limited by a fixed optimization function, failing to consider the three-dimensional parameter space of power-exposure time-point spacing in the point-scan mode. This leads to insufficient energy density control precision, affecting the uniformity of microstructure.

[0005] In summary, neither the traditional LPBF vector scanning process nor the improved method based on path thermal balance optimization can meet the current high-end manufacturing industry's demand for high-precision, high-performance LPBF metal 3D printed parts. Therefore, it is urgent to propose a better LPBF process solution to overcome the above-mentioned technical limitations and improve the quality of the formed parts and the stability of the process. Summary of the Invention

[0006] This invention provides an LPBF metal 3D printing method and system based on discrete point dynamic control, which transforms the traditional one-dimensional vector line scanning path into a zero-dimensional and programmable dot matrix. Each scanning point is individually assigned scanning power and laser exposure time, enabling inertial-free scanning of arbitrary geometric paths and complex features. It is suitable for high-end application scenarios such as lightweight dot matrix structures in aerospace and porous implants in medical devices, filling the technological gap in precision-efficiency-material synergistic optimization of existing metal 3D printing.

[0007] This invention provides an LPBF metal 3D printing method based on discrete point dynamic control, comprising:

[0008] S1. Decompose the outline of the slice layer of the 3D model into a lattice with a set density and uniformly distributed scanning points.

[0009] S2. Set the laser parameters for each scanning point in the dot matrix, and perform one laser scan for each scanning point according to the laser parameters; wherein, the laser parameters include power and exposure time;

[0010] S3. Based on the dot matrix, plan the scanning order of all scanning points as the scanning path;

[0011] S4, controlling the laser to scan according to the scanning path, and using the corresponding laser parameter of each scanning point on the scanning path for scanning;

[0012] S5, converting to the next slice of the 3D model, and repeating steps S1-S4 until the scanning of the entire 3D model is completed.

[0013] Further, in the S1, the spacing of each scanning point in the dot matrix ranges from 15 to 150 μm.

[0014] Further, in the S2, the single-point laser exposure parameter is set according to the dot matrix, and specifically:

[0015] By switching between "high power + long exposure" and "low power + short exposure", the laser energy density window that can make the material form without defects is quickly determined;

[0016] Within the determined laser energy density window, different parameter combinations of "high power + short exposure" and "low power + long exposure" are adjusted to find laser exposure parameters that meet the forming quality requirements and strength requirements.

[0017] Further, different laser scanning parameters and scanning paths in the dot matrix are selected according to the properties of the alloy for scanning.

[0018] Further, in the S3, the dot matrix is divided into multiple partitions, each partition corresponds to a laser, and the scanning order of all scanning points in each partition is set as a partition scanning path, and multiple lasers simultaneously scan according to the corresponding partition scanning path.

[0019] Further, according to the requirements of TSP (Traveling Salesman Problem) algorithm and heat balance, the scanning path between the scanning points or the partition scanning path is planned according to the dot matrix.

[0020] The application also provides a LPBF metal 3D printing system based on dynamic regulation of discrete points, based on the LPBF metal 3D printing method based on dynamic regulation of discrete points as described above, the system comprises a high-power laser light source, a beam shaping module, a high-speed galvanometer scanning module, a point scanning control module, a powder laying module, an inert gas protection module and an online monitoring module,

[0021] The online monitoring module monitors the molten pool in real time, and feeds back signals to the point scanning control module, the high-power laser light source and the high-speed galvanometer scanning module;

[0022] The point scanning control module transmits powder laying instructions to the powder laying module, transmits scanning instructions to the high-speed galvanometer scanning module, and transmits control instructions to the high-power laser light source and the beam shaping module by using the LPBF metal 3D printing method based on dynamic regulation of discrete points.

[0023] The high-power laser light source is also connected to the beam shaping module for beam expansion, collimation and dynamic focusing, and the beam shaping module is connected to the high-speed galvanometer scanning module to realize laser scanning on the laser beam emitted by the molten pool.

[0024] The powder laying module lays powder on the molten pool, and the inert gas protection module provides an inert atmosphere for the molten pool.

[0025] Further, the high-power laser light source uses a fiber laser or a disc laser to provide a laser beam required for melting of metal powder;

[0026] The beam shaping module includes an expansion mirror, a collimation mirror and a dynamic focusing unit to ensure adjustable laser spot size;

[0027] The high-speed galvanometer scanning module is composed of X / Y axis galvanometers to realize rapid deflection of the laser focal point in the processing plane.

[0028] The point scanning control module controls the galvanometer by using the LPBF metal 3D printing method based on dynamic regulation of discrete points, so that the laser moves according to the set scanning mode along the scanning path or the partition scanning path;

[0029] The powder laying module includes a powder supply cylinder and a powder laying scraper / roller to ensure uniform laying of metal powder for each slice;

[0030] The inert gas protection module maintains a low-oxygen environment for the molten pool to prevent metal oxidation;

[0031] The online monitoring module integrates an infrared thermal imager or a high-speed camera to monitor the molten pool shape in real time and feedback adjust the laser power or scanning speed.

[0032] The beneficial effects of the present application are:

[0033] 1. Flexibility of arbitrary path: support high-precision forming of complex geometric features (such as honeycomb structure, conformal runner), not subject to continuous scanning trajectory constraints.

[0034] 2. Accurate control of heat input: through independent adjustment of point parameters, reduce thermal stress and deformation, and improve mechanical properties of parts.

[0035] 3. Wide material applicability: can adapt to high-reflectivity materials (such as copper alloy), brittle materials (such as tungsten) and other traditional LPBF difficult-to-machine materials.

[0036] 4. High efficiency and low defects: high-speed mirror jumping combined with pulse modulation to achieve high production rate while suppressing defects such as pores and spheroidization. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flowchart of the LPBF metal 3D printing method based on dynamic regulation of discrete points of the application.

[0038] Figure 2 The structural diagram of the LPBF metal 3D printing system based on dynamic regulation of discrete points of the application.

[0039] The realization of the object, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0040] It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0041] The application introduces a high-dynamic point scanning mode, which can continue to convert the traditional one-dimensional vector line scanning path into a zero-dimensional programmable dot matrix, support any geometric trajectory (including non-continuous jumping), and realize inertia-free scanning of complex features. At the same time, the parameter logic is converted from the traditional laser scanning power (P) and laser scanning speed (v) to laser scanning power (P) and laser exposure time (t), each molten pool (scanning point) is individually assigned, wherein the power adjustable range is 15-500W, the step is 1W, the time adjustable range is ≥10μs, the step is ≥5μs, the complete uniform distribution of thermal stress and independent modulation of temperature field can be realized. It is suitable for high-end application scenarios such as aerospace lightweight dot matrix structure, medical porous implant, etc., and fills the technical gap of existing metal 3D printing in precision-efficiency-material collaborative optimization.

[0042] As shown in Figure 1 The application provides a LPBF metal 3D printing method based on dynamic regulation of discrete points, which controls the laser focus to scan in discrete point mode through high-dynamic galvanometer, breaks through the limitations of traditional LPBF vector line scanning, and the specific steps are as follows:

[0043] S1, path discretization and dot matrix generation

[0044] The slice layer profile range of the 3D model is divided into a dot matrix with a set density and uniform distribution of scanning points, the range of the distance between each scanning point in the dot matrix is 15-150μm, and each point corresponds to one scanning (melting) action of the laser.

[0045] S2, dynamic power-exposure time collaborative control

[0046] setting laser parameters for each scanning point in the dot matrix, each scanning point performing one scan of laser light according to the laser parameters; wherein the laser parameters include power and exposure time.

[0047] In one embodiment, single-point laser exposure parameters are set according to the dot matrix, specifically:

[0048] Through switching between "high power + long exposure" and "low power + short exposure", a laser energy density window is quickly determined that allows the material to be initially formed without obvious defects such as ablation, warping or excessive melting;

[0049] Within the determined laser energy density window, further adjustments are made by continuously adjusting different parameter combinations such as "high power + short exposure" and "low power + long exposure" to find exposure parameters that meet the following specific forming quality requirements and strength requirements:

[0050] ① Forming quality requirements: the formed structure surface is smooth and clear in outline, without obvious defects such as spheroidization, porosity or cracking, and the dimensional accuracy error is controlled within ±0.01%.

[0051] ② Strength requirements: the tensile strength of the formed sample is not lower than the material and process requirements.

[0052] Finally, different laser scanning parameters and scanning paths within the dot matrix are selected according to the properties of the alloy to achieve the effect of independent adjustment of laser parameters (power, exposure time) for each scanning point, for example:

[0053] High power short dwell (such as 300W, 50μs) is used for deep penetration of high melting point alloys (such as titanium alloys), and low power long dwell (such as 100W, 200μs) is used for fine forming of thin-walled structures. At the same time, pulse modulation technology can be combined to convert continuous laser into high-frequency pulse (kHz-MHz), further reducing heat accumulation.

[0054] S3, plan the scanning order of all scanning points as a scanning path based on the dot matrix.

[0055] In one embodiment, multi-laser collaborative optimization can also be performed, i.e., the dot matrix is divided into multiple partitions, each partition corresponds to one laser, and the scanning order of all scanning points in each partition is set as a partition scanning path, and multiple lasers simultaneously scan according to their corresponding partition scanning paths.

[0056] In one embodiment, galvanometer efficiency optimization can also be performed, i.e., the shortest path between scanning points is planned as a scanning path or partition scanning path according to the dot matrix through a TSP (Traveling Salesman Problem) algorithm, reducing galvanometer idle time.

[0057] S4, control the laser to scan according to the scanning path, and use the corresponding laser parameter of each scanning point on the scanning path for scanning.

[0058] S5, switch to the next slice of the 3D model, and repeat steps S1-S4 until the scanning of the entire 3D model is completed.

[0059] As Figure 2 shown, the application also provides a LPBF metal 3D printing system based on dynamic regulation of discrete points, based on the LPBF metal 3D printing method based on dynamic regulation of discrete points as described above, the system comprises a high-power laser light source, a beam shaping module, a high-speed galvanometer scanning module, a point scanning control module, a powder laying module, an inert gas protection module and an online monitoring module.

[0060] (1) High-power laser light source

[0061] The high-power laser light source is connected to the beam shaping module for beam expansion, collimation and dynamic focusing. The high-power laser light source uses a fiber laser or a disc laser (wavelength is usually 1064nm or 1070nm), which provides a high-energy density laser beam required for melting of metal powder.

[0062] (2) Beam shaping module

[0063] The beam shaping module is connected to the high-speed galvanometer scanning module to realize laser scanning of the laser beam emitted by the molten pool. The beam shaping module includes an expansion mirror, a collimation mirror and a dynamic focusing system, which ensures that the laser spot size is adjustable (such as 50-200μm) to adapt to different powder materials and processing requirements.

[0064] (3) High-speed galvanometer scanning module

[0065] The high-speed galvanometer scanning module is composed of X / Y axis galvanometer, which realizes the rapid deflection of the laser focus in the processing plane, and the scanning speed can reach several meters per second.

[0066] (4) Powder laying module

[0067] The powder laying module lays powder on the molten pool, including a powder supply cylinder and a powder laying scraper / roller, which ensures uniform laying of each layer of metal powder (layer thickness is usually 30-200μm).

[0068] (5) Inert gas protection module

[0069] The inert gas protection module provides an inert atmosphere for the molten pool, maintains a low-oxygen environment (such as argon or nitrogen) in the processing cabin, and prevents metal oxidation.

[0070] (6) Point scanning control module

[0071] The point scanning control module transmits powder spreading instructions to the powder spreading module, scan instructions to the high-speed galvanometer scanning module, and control instructions to the high-power laser source and beam shaping module using the LPBF metal 3D printing method based on discrete point dynamic control.

[0072] The point scanning control module controls the galvanometer through a real-time path planning algorithm (arbitrary point scanning or sequential scanning, which is a manually preset path or an algorithm-generated path), so that the laser moves along a preset path in point scanning mode (non-vector scanning), supporting arbitrarily complex trajectories.

[0073] (7) Online monitoring module

[0074] The online monitoring module monitors the molten pool in real time and feeds back signals to the point scanning control module, the high-power laser source, and the high-speed galvanometer scanning module. The online monitoring module integrates an infrared thermal imager or a high-speed camera to monitor the molten pool morphology in real time and adjust the laser power or scanning speed accordingly.

[0075] The feedback adjustment of the online monitoring module is a closed-loop control process, and the specific principle is as follows:

[0076] ①Signal acquisition: Infrared thermal imagers or high-speed cameras continuously acquire images and temperature data of the molten pool during laser processing.

[0077] ②Feature extraction: The processing system analyzes these data in real time and extracts key feature parameters, such as the width (W), length (L), area, and maximum temperature (T_max) of the molten pool.

[0078] ③ Comparison and judgment: The extracted real-time feature values ​​are compared with the ideal target values ​​(or allowable ranges) under the current process parameters.

[0079] ④ Closed-loop feedback control: Based on the comparison deviation, the point scan control module immediately issues an adjustment command:

[0080] If the molten pool size (e.g., width) is detected to be too large or the temperature too high: this indicates excessive energy input, posing a risk of burn-through or spatter. The control module will immediately reduce the laser power and / or increase the scanning speed to decrease heat input and restore the molten pool to a normal state.

[0081] When the molten pool size is detected to be too small or the temperature too low, it is determined that the energy input is insufficient, and there is a risk of incomplete fusion or spheroidization. The control module will immediately increase the laser power and / or reduce the scanning speed to increase the heat input, ensuring that the powder melts completely and bonds well with the matrix.

[0082] Compared with traditional continuous laser scanning methods, this invention has the following significant advantages:

[0083] 1. Significantly improve the forming accuracy and adaptability of complex structure

[0084] Micron-level feature forming capability: through the discrete point scanning strategy, the laser energy can be accurately applied to the micro area (the point spacing can be adjusted to 10 μm level), high resolution forming is realized, and the minimum feature size reaches ± 15 μm, which is several times higher than that of traditional continuous scanning (± 30 μm).

[0085] Complex geometry inertia-free forming: get rid of the path continuity restriction of continuous scanning, support inertia-free high-fidelity manufacturing of complex features such as overhanging structure, dot lattice, internal flow channel, etc., and the corner accuracy is improved by more than 60%.

[0086] 2. Accurate control of heat input, improve the mechanical properties of parts

[0087] Micro-area energy independent regulation: the power and residence time of each scanning point can be dynamically adjusted, so that the heat input matches the local geometry / material properties, and the residual stress uniformity is improved by more than 80%.

[0088] Active thermal management: through regional jumping scanning (such as chessboard, spiral filling), the accumulation of thermal stress is optimized, the warping deformation is reduced, and the flatness error of large size parts (> 200mm) is controlled within 0.1mm / m.

[0089] 3. Expand the material process window and break through the bottleneck of extreme material processing

[0090] High-reflective material high densification forming: pulse point scanning mode overcomes the laser reflection loss of copper and aluminum alloy, copper alloy density reaches 99.2% (traditional method < 98%), and the conductivity is close to the level of forgings.

[0091] Brittle material low defect manufacturing: short residence time (< 100 μs) inhibits thermal cracks of tungsten, ceramic and other materials, crack rate is reduced by 80%, and relative density is > 99%.

[0092] 4. Maximize equipment dynamic performance and improve production efficiency

[0093] Efficiency release of galvanometer: based on the point path optimization algorithm of TSP (traveling salesman problem), the proportion of high-speed jumping of galvanometer is increased from 40% to 85%, and the printing efficiency of complex structure is increased by 2-3 times.

[0094] Multi-laser collaborative expansion: support multi-laser head partition parallel point scanning, large parts (such as aircraft engine casing) manufacturing cycle is shortened by 50%.

[0095] In summary, the key technical points of the present application are:

[0096] 1. Process flexibility is improved by an order of magnitude from one-dimensional vector line scanning to zero-dimensional point scanning. One-dimensional vector line scanning has direction and length, and its process flexibility has a certain upper limit; zero-dimensional point scanning has no direction and length, and its process flexibility has no upper limit. Its path planning is not dependent on geometric constraints, but only on process quality and efficiency requirements.

[0097] 2. Precise point-by-point energy control. The dynamic matching of two key parameters, laser scanning power (P) and laser exposure time (t), with laser model (spot diameter), printing material, and layer thickness, realizes precise point-by-point energy control.

[0098] 3. Point scanning path generation logic. Non-continuous point scanning strategies such as chessboard, spiral, and random point sequence disperse heat accumulation; point spacing adaptive adjustment algorithm (according to real-time temperature feedback, dynamically reduces / enlarges point spacing).

[0099] The application in high-value aerospace parts includes:

[0100] ① Turbine blades: precise control of energy input in thin-walled areas (≤0.3mm) of the blade body through point scanning, eliminating local burn-through defects caused by traditional line scanning.

[0101] ② Spacecraft fuel nozzle: use point-to-point jump scanning strategy to reduce residual stress in the internal flow channel and avoid crack initiation under high pressure.

[0102] Technical advantage: meets the requirement of NASM (American Aerospace Material Standard) for internal defect rate ≤0.01%.

[0103] The application in personalized customization of medical implants includes:

[0104] ① Porous titanium alloy bone scaffold: dynamically adjust porosity (gradient 50%-90%) through point scanning to match the mechanical properties of patient's bone and cell ingrowth requirements.

[0105] ② Dental implant: based on CBCT data, directly generate point scanning path to realize biomechanical optimization of root canal thread structure.

[0106] Technical advantage: surface roughness can be controlled within Ra5-20μm (promote bone integration), and avoid powder adhesion problem of electron beam melting (EBM).

[0107] The application in precise mold conformal cooling waterway includes:

[0108] ① Use point scanning + real-time infrared monitoring to print complex spiral cooling channels (diameter φ1mm±0.05mm) inside the mold, and improve cooling efficiency by 40%.

[0109] ②Through point energy grading control, mirror polishing (Ra≤0.8 μm) of the inner wall of the water channel and high strength of the outer cavity are realized.

[0110] Technical advantage: solve the design limitation of the traditional drilling process that cannot realize the curved water channel.

[0111] The application mode of the application in metamaterials and functionally graded materials includes:

[0112] ①Acoustic metamaterial: by adjusting the stiffness of the unit structure (energy density difference ±15%) point by point, the specific frequency band (such as 500-1000Hz) sound wave shielding is realized.

[0113] ②Thermal protection gradient material: in a single printing, the microstructure gradually changes from tungsten (melting point 3422℃) to copper (thermal conductivity 401W / mK).

[0114] Technical barrier breakthrough: traditional LPBF cannot realize sub-millimeter gradient due to material switching delay.

[0115] The application mode of the application in micro-nano scale electronic devices includes:

[0116] ①Radio frequency device heat dissipation substrate: point scanning printing microneedle array (height 50 μm, spacing 10 μm), using surface area multiplication effect to improve heat dissipation performance.

[0117] ②Flexible circuit metal interconnection: low-temperature point scanning silver nanoparticle wire (conductivity ≥80%IACS) on a polyimide substrate.

[0118] Innovation point: combined with short pulse (ns level) point scanning to suppress the heat affected zone.

[0119] The application mode of the application in space on-orbit manufacturing includes:

[0120] ①In the microgravity environment, through point scanning + gas flow field cooperative control, the problem of metal molten pool drift is solved, and satellite spare parts are printed.

[0121] ②Using the low heat input characteristics of point scanning, aluminum alloy structure repair is completed under the condition of limited power (≤500W) of space station.

[0122] Technical adaptability: compared with traditional LPBF, 60% of inert gas consumption is reduced.

[0123] It is to be understood that the terminology "including", "comprising", or any other variation thereof, is intended to cover a non-exclusive inclusion such that process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises a... " does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0124] The above description is merely the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made according to the content of the present application specification and drawings, or directly or indirectly applied to other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A LPBF metal 3D printing method based on dynamic regulation of discrete points, characterized in that, The method comprises the following steps: S1. The profile range of a slice layer of a 3D model is divided into a point array with a set density and uniform distribution of scanning points; S2. Laser parameters of each scanning point in the point array are set, and each scanning point performs a laser scan according to the laser parameters; wherein the laser parameters include power and exposure time, and single-point laser exposure parameters are set according to the point array, specifically: Through switching between "high power + long exposure" and "low power + short exposure", the laser energy density window that makes the material form without defects is quickly determined; Within the determined laser energy density window, different parameter combinations of "high power + short exposure" and "low power + long exposure" are adjusted to find laser exposure parameters that meet the requirements of forming quality and strength; S3. The scanning sequence of all scanning points is planned as a scanning path based on the point array; S4. The laser is controlled to scan according to the scanning path, and each scanning point on the scanning path is scanned using its corresponding laser parameters; S5. The next slice of the 3D model is converted, and steps S1-S4 are repeated until the scanning of the entire 3D model is completed.

2. The dynamic regulation based on discrete points LPBF metal 3D printing method according to claim 1, characterized in that, In S1, the distance between scanning points in the point array ranges from 15 to 150 μm.

3. The dynamic regulation based on discrete points LPBF metal 3D printing method according to claim 1, characterized in that, Different laser scanning parameters and scanning paths in the point array are selected according to the properties of the alloy.

4. The dynamic regulation based on discrete points LPBF metal 3D printing method according to claim 1, characterized in that, In S3, the point array is divided into multiple partitions, each partition corresponds to a laser, and the scanning sequence of all scanning points in each partition is set as a partition scanning path, and multiple lasers simultaneously scan according to their corresponding partition scanning paths.

5. The dynamic regulation based on discrete points LPBF metal 3D printing method according to claim 4, characterized in that, According to the requirements of TSP algorithm and heat balance, the scanning path or partition scanning path is planned according to the point array.

6. A LPBF metal 3D printing system based on dynamic regulation of discrete points, characterized in that, The system of the LPBF metal 3D printing method based on dynamic regulation of discrete points according to any one of claims 1-5 comprises a high-power laser light source, a beam shaping module, a high-speed galvanometer scanning module, a point scanning control module, a powder laying module, an inert gas protection module, and an online monitoring module, The online monitoring module monitors the molten pool in real time and feeds back signals to the point scanning control module, the high-power laser light source, and the high-speed galvanometer scanning module; The point scanning control module transmits powder laying instructions to the powder laying module, transmits scanning instructions to the high-speed galvanometer scanning module, and transmits control instructions to the high-power laser light source and the beam shaping module using the LPBF metal 3D printing method based on dynamic regulation of discrete points; The high-power laser light source is also connected to the beam shaping module for beam expansion, collimation, and dynamic focusing, and the beam shaping module is connected to the high-speed galvanometer scanning module to realize laser scanning by emitting a laser beam to the molten pool; The powder laying module lays powder on the molten pool, and the inert gas protection module provides an inert atmosphere for the molten pool.

7. The discrete point dynamically regulated LPBF metal 3D printing system according to claim 6, wherein, The high-power laser light source uses a fiber laser or a disc laser to provide a laser beam required for melting metal powder; The beam shaping module includes an expansion mirror, a collimation mirror, and a dynamic focusing unit to ensure that the size of the laser spot is adjustable; The high-speed galvanometer scanning module is composed of an X / Y axis galvanometer, which realizes rapid deflection of the laser focal point in the processing plane. The point scanning control module controls the galvanometer through the LPBF metal 3D printing method based on dynamic regulation of discrete points, so that the laser moves according to the set scanning mode along the scanning path or the partition scanning path. The powder laying module includes a powder supply cylinder and a powder laying scraper / roller to ensure uniform laying of metal powder for each slice. The inert gas protection module maintains a low-oxygen environment for the molten pool to prevent metal oxidation. The online monitoring module integrates an infrared thermal imager or a high-speed camera to monitor the molten pool shape in real time and feedback adjust the laser power or scanning speed.

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