A dynamic scanning method, apparatus, and additive manufacturing equipment for laser sintering.

Abstract

A dynamic scanning method, device and additive manufacturing equipment for laser sintering, wherein the dynamic scanning method for laser sintering includes: dividing the current layer cross-sectional profile of the working area into two or more regions, using a Gaussian spot A for laser scanning of the region close to the profile, and using a double-normal spot B for laser scanning of the region far from the profile; wherein, the size ratio Rb:Ra of the Gaussian spot A and the double-normal spot B ∈ (1.2, 5); the highest energy of the Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of the double-normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax < Bmax < 0.95Amax, 0.5Bmax < Bmin < Bmax. The dynamic scanning method, device and additive manufacturing equipment for laser sintering of the present invention combine zonal scanning with spot energy adjustment to ensure printing quality and workpiece performance while improving printing efficiency.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to a dynamic scanning method, apparatus and additive manufacturing equipment for laser sintering. Background Technology

[0002] Additive manufacturing is a rapid manufacturing technology that uses a laser to scan and stack layers to form a three-dimensional object. The process flow is as follows: First, the three-dimensional model of the workpiece is sliced ​​to obtain the contour information of each layer. Powdered material is then evenly spread on the surface of the work platform, and the laser selectively melts the powder according to system instructions. After one section is completed, a new layer of material is laid on top, and scanning continues selectively based on the cross-sectional information corresponding to the three-dimensional object. This process is repeated for the next section, ultimately resulting in the three-dimensional object.

[0003] Current selective laser melting (SLM) technology (one of the additive manufacturing technologies) mainly uses a traditional Gaussian laser spot. This spot exhibits a normal energy distribution, with a high energy density at the center and gradually decreasing towards the edges. While this energy distribution can meet most processing needs, it has significant limitations for the following applications: 1. Heat concentration: For heat-sensitive materials, excessively high laser power can easily cause warping and deformation, leading to printing failure. 2. High reflectivity material limitations: High-reflectivity metals such as aluminum alloys and copper alloys have poor adaptability to the Gaussian laser spot energy distribution, resulting in low material absorption efficiency and affecting the forming quality. 3. Printing large and complex structures: As the size and complexity of parts increase, printing time increases significantly. The equipment may be interrupted due to external factors such as shielding gas depletion, lens contamination, or power outages, significantly affecting printing stability. 4. Melt pool stability: Increasing the spot size can improve printing speed, but it reduces molten pool stability, leading to increased surface roughness.

[0004] To address these issues, printing efficiency is typically improved by increasing the number of lasers or optimizing the scanning path. However, these measures may increase equipment costs or introduce new quality problems such as processing instability. Therefore, how to improve efficiency while ensuring printing quality has become a core issue in additive manufacturing technology research. Summary of the Invention

[0005] To address the aforementioned technical problems in the existing technology, this invention provides a dynamic scanning method, apparatus, and additive manufacturing equipment for laser sintering. This dynamic scanning method for laser sintering combines partitioned scanning with spot energy adjustment, thereby improving printing efficiency while ensuring printing quality and workpiece performance.

[0006] To achieve the above objectives, the present invention provides a dynamic scanning method for laser sintering, comprising the following steps:

[0007] The current layer cross-sectional profile of the working area is divided into two or more regions. Regions close to the profile are scanned using a Gaussian spot A, while regions far from the profile are scanned using a dual-normal spot B.

[0008] The size ratio of Gaussian spot A and double normal spot B is Rb:Ra∈(1.2,5);

[0009] The highest energy of Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of double normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax <Bmax<0.95Amax,0.5Bmax<Bmin<Bmax。

[0010] As a further preferred embodiment of the present invention, when the current layer cross-sectional contour of the working area is divided into two regions, laser scanning is performed on the region close to the contour using a Gaussian spot A, and laser scanning is performed on the region far from the contour using a double normal spot B. Specifically, this includes:

[0011] The current layer cross-sectional profile of the working area is divided into region A and region B using a virtual contour. Region A is the area enclosed by the actual contour and the virtual contour of the current layer cross-sectional profile. Region B is all the areas enclosed by the virtual contour. The virtual contour has the same shape as the actual contour, and the area of ​​the virtual contour is smaller than the area of ​​the actual contour.

[0012] Region A is scanned using a Gaussian spot A, and region B is scanned using a double normal spot B.

[0013] As a further preferred embodiment of the present invention, region B is first scanned using a double normal light spot B, and then region A is scanned using a Gaussian light spot A.

[0014] As a further preferred embodiment of the present invention, the width of the region A is a, where a∈(4Ra,10mm).

[0015] As a further preferred embodiment of the present invention, when the current layer cross-sectional contour of the working area is divided into two or more regions, laser scanning is performed on the region close to the contour using a Gaussian spot A, and laser scanning is performed on the region far from the contour using a double normal spot B. Specifically, this includes:

[0016] The current layer cross-sectional profile of the working area is divided into several regions along the longitudinal or transverse direction. Two regions close to the profile are laser scanned using a Gaussian spot A, and at least one region far from the profile is laser scanned using a double normal spot B.

[0017] As a further preferred embodiment of the present invention, when the current layer cross-sectional profile of the working area is divided into more than two regions, Gaussian spot A is used for laser scanning in the regions close to the profile, and double-normal spot B is used for laser scanning in the regions far from the profile. Specifically, it includes:

[0018] Determine the centroid position of the current layer cross-sectional profile of the working area. With this centroid as the center, use several "square" shapes of different sizes to divide the current layer cross-sectional profile into several regions from the inside to the outside. Starting from the regions close to the profile, switch and scan adjacent regions with Gaussian spot A and double-normal spot B in turn.

[0019] As a further preferred embodiment of the present invention, the distance between adjacent "square" shapes is the same.

[0020] As a further preferred embodiment of the present invention, the filling power, filling speed, and filling spacing of Gaussian spot A and double-normal spot B respectively meet the following conditions:

[0021] Filling power: 0.7Pb ≤ Pa ≤ 0.9Pb;

[0022] Filling speed: 0.9Sb ≤ Sa ≤ Sb;

[0023] Filling spacing: 0.6Db ≤ Da ≤ 0.9Db;

[0024] Where, Pa is the filling power of Gaussian spot A, Pb is the filling power of double-normal spot B, Sa is the filling speed of Gaussian spot A, Sb is the filling speed of double-normal spot B, Da is the filling spacing of Gaussian spot A, and Db is the filling spacing of double-normal spot B.

[0025] The present invention also provides a dynamic scanning device for an additive manufacturing equipment, including a memory and a processor. The memory stores a computer program. It is characterized in that when the processor executes the computer program, it implements the steps of the dynamic scanning method for laser sintering described in any one of the above.

[0026] The present invention also provides an additive manufacturing equipment, which includes the dynamic scanning device of the above-mentioned additive manufacturing equipment.

[0027] The dynamic scanning method, device, and additive manufacturing equipment of the present invention for laser sintering significantly improve the efficiency and quality of laser additive manufacturing by combining dynamic spot regulation and zonal scanning. Specifically, it includes the following beneficial effects:

[0028] 1. The dynamic scanning strategy effectively optimizes the utilization rate of the spot and significantly shortens the printing time of large and complex workpieces;

[0029] 2. Precise energy control and zonal design reduce stress concentration and warpage deformation;

[0030] 3. By adjusting the spot energy, the central energy density can be reduced, the heat concentration effect can be reduced, and at the same time, the forming ability for highly reflective materials and complex workpieces can be improved, so as to meet the forming requirements of highly reflective materials and complex geometric parts.

[0031] 4. Provide single-cut and multi-cut dynamic scanning strategy modes, which can cover printing scenarios from small-sized fine structures to large-sized complex structures. Brief Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the energy distribution of the Gaussian spot A and the double-normal spot B of the present invention;

[0033] Figure 2 It is a scanning schematic diagram of Embodiment 1 provided by the dynamic scanning method for laser sintering of the present invention;

[0034] Figure 3 It is a scanning schematic diagram of Embodiment 2 provided by the dynamic scanning method for laser sintering of the present invention;

[0035] Figure 4 It is a scanning schematic diagram of Embodiment 3 provided by the dynamic scanning method for laser sintering of the present invention; Detailed Embodiments

[0036] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application and are not used to limit the present application.

[0037] The dynamic scanning method for laser sintering provided by the present invention includes the following steps:

[0038] Divide the current layer cross-sectional profile of the working area into two or more regions, and use the Gaussian spot A for laser scanning on the regions close to the profile, and use the double-normal spot B for laser scanning on the regions far from the profile; wherein,

[0039] The size ratio Rb:Ra of the Gaussian spot A and the double-normal spot B ∈ (1.2, 5);

[0040] The highest energy of the Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of the double-normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax < Bmax < 0.95Amax, 0.5Bmax < Bmin < Bmax. The energies of the above Gaussian spot A and double-normal spot B are respectively as Figure 1 shown (the left figure is the Gaussian spot A, and the right figure is the double-normal spot B).

[0041] As one embodiment of the present invention, when the current layer cross-sectional profile of the working area is divided into two regions, laser scanning is performed on the region close to the profile using a Gaussian spot A, and laser scanning is performed on the region far from the profile using a double normal spot B. Specifically, this includes:

[0042] The current layer cross-sectional profile of the working area is divided into region A and region B using a virtual contour. Region A is the area enclosed by the actual contour and the virtual contour of the current layer cross-sectional profile. Region B is all the areas enclosed by the virtual contour. The virtual contour has the same shape as the actual contour, and the area of ​​the virtual contour is smaller than the area of ​​the actual contour.

[0043] Region A is scanned using a Gaussian spot A, and region B is scanned using a double normal spot B.

[0044] In specific implementation, this application does not restrict the scanning order of region A (also referred to as the A-light scanning region) and region B (also referred to as the B-light scanning region); either region A or region B can be scanned. As one embodiment of this application, region B can be scanned first using a double normal light spot B (also referred to as B-light), and then region A can be scanned using a Gaussian light spot A (also referred to as A-light). Preferably, see [reference needed]. Figure 2 The width of region A is a, where a ∈ (4Ra, 10mm). This ensures printing efficiency while preventing overheating and pores in the workpiece, thereby further improving the surface quality of the workpiece.

[0045] As another embodiment of the present invention, when the current layer cross-sectional contour of the working area is divided into two or more regions, laser scanning is performed on the region close to the contour using a Gaussian spot A, and laser scanning is performed on the region far from the contour using a double normal spot B. Specifically, this includes:

[0046] The current layer cross-sectional profile of the working area is divided into several regions along the longitudinal or transverse direction. Two regions close to the profile are laser-scanned using a Gaussian spot A, while at least one region far from the profile is laser-scanned using a double normal spot B. For details, see [link to documentation]. Figure 3 The current layer's cross-sectional profile can be divided into n+1 and n parts (n = 1, 2, 3…10, where n is a natural number) according to two widths, a and b. For example, when n = 1, the current layer's cross-sectional profile is divided into two regions of width a for Gaussian spot A scanning and one region of width b for double normal spot B scanning. Understandably, the value of n can be set according to actual printing needs. A larger value of n results in better heat reduction, but also longer printing time. Therefore, the specific value of n can be set by the designer according to specific requirements, and will not be detailed here.

[0047] As another embodiment of the present invention, when the current layer cross-sectional profile of the working area is divided into more than two regions, Gaussian spot A is used for laser scanning of the regions close to the profile, and double-normal spot B is used for laser scanning of the regions far from the profile. Specifically, it includes:

[0048] Determine the centroid position of the current layer cross-sectional profile of the working area. With this centroid as the center, use several "square" shapes of different sizes to divide the current layer cross-sectional profile into several regions from the inside out. Starting from the regions close to the profile, switch and scan adjacent regions with Gaussian spot A and double-normal spot B in turn. Specifically, cyclic scanning can be carried out in the order of Gaussian spot A, double-normal spot B, Gaussian spot A, double-normal spot B... until the scanning of the current layer cross-sectional profile is completed.

[0049] Specifically, let the scanning widths of the regions for Gaussian spot A scanning and the regions for double-normal spot B scanning be Da and Db respectively. By adjusting the values of Da and Db, the number of divided regions can be controlled; the lower the value, the more regions are divided. This can well reduce the internal stress concentration phenomenon, but correspondingly increase the printing time.

[0050] For irregular printing layers, the galvanometer system still scans along the original "square" route. The laser does not emit light in the printing area outside the route, and the laser emits light again after scanning to the printing area.

[0051] Preferably, the spacing between adjacent "squares" is the same, and Rb:Ra = 2. Because the same spacing will make the heat input distribution of two adjacent laser beams relatively uniform during the scanning process, avoiding excessive heat concentration in a certain direction, thereby reducing the risk of local overheating or thermal deformation. This can reduce the possibility of defects such as surface depressions or ripples. Moreover, the consistent spacing can also make the scanning process more coherent, reduce the pauses during multiple switches, thereby improving the processing efficiency and reducing the risks that the software may generate due to excessive partitioning.

[0052] Further preferably, in order to improve the forming efficiency and reduce the risk of molten pool instability at the same time, the filling power, filling speed, and filling spacing of the Gaussian spot A and the double-normal spot B respectively satisfy the following conditions:

[0053] Filling power: 0.7Pb ≤ Pa ≤ 0.9Pb;

[0054] Filling speed: 0.9Sb ≤ Sa ≤ Sb;

[0055] Filling spacing: 0.6Db ≤ Da ≤ 0.9Db;

[0056] Where Pa is the filling power of Gaussian spot A, Pb is the filling power of bisnormal spot B, Sa is the filling speed of Gaussian spot A, Sb is the filling speed of bisnormal spot B, Da is the filling spacing of Gaussian spot A, and Db is the filling spacing of bisnormal spot B.

[0057] The present invention also provides a dynamic scanning device for additive manufacturing equipment, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the dynamic scanning method for laser sintering described in any of the above embodiments.

[0058] The present invention also provides an additive manufacturing apparatus, which includes the dynamic scanning device of the additive manufacturing apparatus described above.

[0059] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the technical solutions of the present invention will be described in detail below through embodiments and in conjunction with the accompanying drawings.

[0060] Example 1

[0061] The dynamic scanning method for laser sintering in this embodiment includes the following steps:

[0062] Step 11: Divide the current layer cross-sectional profile of the working area into two or more regions;

[0063] Step 12: Divide the current layer cross-sectional profile of the working area into region A and region B using a virtual contour. Region A is the area enclosed by the actual contour and the virtual contour of the current layer cross-sectional profile. Region B is all the areas enclosed by the virtual contour. The virtual contour has the same shape as the actual contour, and the area of ​​the virtual contour is smaller than the area of ​​the actual contour.

[0064] Step 13: First, scan region B using a double normal light spot B, then scan region A using a Gaussian light spot A. The width of region A is a = 0.5 mm; Figure 2 As shown, where,

[0065] The sizes of Gaussian spot A and double normal spot B are Ra = 30 μm and Rb = 60 μm, respectively;

[0066] The highest energy of Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of double normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax <Bmax<0.95Amax,0.5Bmax<Bmin<Bmax。

[0067] The dynamic scanning method in this embodiment can also be called a "single-cut" dynamic scanning strategy, meaning the laser spot only switches once. For high-reflectivity materials, this embodiment can reduce laser energy reflection, improve energy utilization, thereby enhancing print quality and reducing damage to the printing system. For small-sized, high-precision consumer electronics parts, it can improve detail resolution while increasing speed, ensuring the printing accuracy of small, fine structures. For small to medium-sized, complex aerospace parts with significant stress, it can reduce localized stress concentration by precisely controlling heat input, improving the mechanical properties and durability of the parts.

[0068] Example 2

[0069] The dynamic scanning method for laser sintering in this embodiment includes the following steps:

[0070] Step 21: Divide the current layer cross-sectional profile of the working area into two or more regions;

[0071] Step 22: Divide the current layer cross-sectional profile of the working area into several regions along the longitudinal or transverse direction. Use a Gaussian spot A to laser scan the two regions closest to the profile, and use a double normal spot B to laser scan at least one region far from the profile; For example... Figure 3 As shown, the areas of the several regions are not equal; in specific implementations, the areas of the several regions can be equal.

[0072] The sizes of Gaussian spot A and double normal spot B are Ra = 70 μm and Rb = 150 μm, respectively;

[0073] The highest energy of Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of double normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax <Bmax<0.95Amax,0.5Bmax<Bmin<Bmax。

[0074] The dynamic scanning method in this second embodiment can also be called a "multi-cut" dynamic scanning strategy, which involves switching the light spot two or more times. This embodiment has lower workpiece stress and higher mechanical properties, extending the service life of the workpiece to be printed, and is suitable for printing large-size workpieces.

[0075] Example 3

[0076] The dynamic scanning method for laser sintering in this embodiment includes the following steps:

[0077] Step 31: Divide the current layer cross-sectional profile of the working area into two or more regions;

[0078] Step 32: Determine the centroid position of the current layer cross-sectional profile in the working area. Using this centroid as the center, divide the current layer cross-sectional profile into several regions from the inside out using several square-shaped patterns of different sizes. Starting from the region closest to the profile, sequentially switch between Gaussian spot A and double normal spot B for scanning each adjacent region; for example... Figure 4 As shown, where,

[0079] The sizes of Gaussian spot A and double normal spot B are Ra = 90 μm and Rb = 400 μm, respectively;

[0080] The highest energy of Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of double normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax <Bmax<0.95Amax,0.5Bmax<Bmin<Bmax。

[0081] Both this embodiment and Embodiment Two are referred to as the "multi-cut" dynamic scanning strategy, meaning the light spot switches two or more times. This embodiment exhibits lower workpiece stress and higher mechanical properties, extending the lifespan of the workpiece to be printed and making it suitable for printing large-sized workpieces. In contrast, the scanning strategy of Embodiment Three is more suitable for printing workpieces with a relatively complete and regular overall structure, where the workpiece does not have many thin walls, sharp corners, cylinders, or other special structural components.

[0082] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A dynamic scanning method for laser sintering, characterized in that, Includes the following steps: The current layer cross-sectional profile of the working area is divided into two or more regions. Regions close to the profile are scanned using a Gaussian spot A, while regions far from the profile are scanned using a dual-normal spot B. The size ratio of Gaussian spot A to double normal spot B is Rb : Ra ∈ (1.2, 5); The highest energy of Gaussian spot A is Amax, and the lowest energy is Amin; the highest energy of double normal spot B is Bmax, and the lowest energy is Bmin; 0.65Amax < Bmax < 0.95Amax, 0.5Bmax < Bmin < Bmax; where, The filling power, filling speed, and filling spacing of the Gaussian spot A and the double normal spot B respectively satisfy the following conditions: Fill power: 0.7Pb ≤ Pa ≤ 0.9Pb; Filling speed: 0.9Sb ≤ Sa ≤ Sb; Fill spacing: 0.6Db ≤ Da ≤ 0.9Db; Where Pa is the filling power of Gaussian spot A, Pb is the filling power of bisnormal spot B, Sa is the filling speed of Gaussian spot A, Sb is the filling speed of bisnormal spot B, Da is the filling spacing of Gaussian spot A, and Db is the filling spacing of bisnormal spot B.

2. The dynamic scanning method for laser sintering according to claim 1, characterized in that, When the current layer cross-sectional profile of the working area is divided into two regions, the region closer to the profile is laser-scanned using a Gaussian spot A, and the region farther from the profile is laser-scanned using a double normal spot B. Specifically, this includes: The current layer cross-sectional profile of the working area is divided into region A and region B using a virtual contour. Region A is the area enclosed by the actual contour and the virtual contour of the current layer cross-sectional profile. Region B is all the areas enclosed by the virtual contour. The virtual contour has the same shape as the actual contour, and the area of ​​the virtual contour is smaller than the area of ​​the actual contour. Region A is scanned using a Gaussian spot A, and region B is scanned using a double normal spot B.

3. The dynamic scanning method for laser sintering according to claim 2, characterized in that, First, region B is scanned using a double normal light spot B, and then region A is scanned using a Gaussian light spot A.

4. The dynamic scanning method for laser sintering according to claim 3, characterized in that, The width of region A is a, where a ∈ (4Ra, 10mm).

5. The dynamic scanning method for laser sintering according to claim 1, characterized in that, When the current layer cross-sectional profile of the working area is divided into more than two regions, the region close to the profile is laser-scanned using a Gaussian spot A, and the region far from the profile is laser-scanned using a double normal spot B. Specifically, this includes: The current layer cross-sectional profile of the working area is divided into several regions along the longitudinal or transverse direction. Two regions close to the profile are laser scanned using a Gaussian spot A, and at least one region far from the profile is laser scanned using a double normal spot B.

6. The dynamic scanning method for laser sintering according to claim 1, characterized in that, When the current layer cross-sectional profile of the working area is divided into more than two regions, the region close to the profile is laser-scanned using a Gaussian spot A, and the region far from the profile is laser-scanned using a double normal spot B. Specifically, this includes: Determine the centroid position of the current layer cross-sectional profile of the working area, and use several "square" shapes with different sizes to divide the current layer cross-sectional profile into several regions from the inside out with the centroid as the center. Starting from the region close to the profile, switch and scan adjacent regions in sequence with Gaussian spot A and double-normal spot B respectively.

7. The dynamic scanning method for laser sintering according to claim 6, characterized in that, The spacing between adjacent "square" shapes is the same.

8. A dynamic scanning device for additive manufacturing equipment, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the dynamic scanning method for laser sintering according to any one of claims 1 to 7.

9. An additive manufacturing apparatus, characterized in that, It includes the dynamic scanning device of the additive manufacturing equipment according to claim 8.

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