Self-adaptive process method for laser additive manufacturing

Abstract

The invention discloses a laser additive manufacturing self-adaptive process method which can be used for carrying out self-adaptive or refined correction on laser processing process parameters according to different geometrical shapes of parts and difference of light spots in an inherent breadth of a printing laser f-theta laser system and different forming positions in a forming process. According to the method, the manufacturability is greatly improved, the consistency of the forming quality is ensured, the forming stability, the forming quality and the printing success rate are improved, meanwhile, the geometric limit of laser additive manufacturing is further broken through, and the method has the refined regulation and control capacity of technological parameters.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing, and specifically relates to an adaptive process method for laser additive manufacturing. Background Technology

[0002] Metal additive manufacturing technology has evolved over many years, from a few initial processes to various technical routes such as laser powder bed melting and electron beam melting. The range of printable materials has also expanded, and printing accuracy, speed, and stability have significantly improved. As a crucial strategic technology for the future, various countries have launched programs to support its development. Based on its numerous advantages, including prototyping and the manufacturability of complex structures after topology optimization, it has played a vital role in key industrial sectors, effectively promoting technological development in these areas. Particularly in the aerospace field, it efficiently manufactures complex, high-performance components, effectively reducing costs and timelines.

[0003] Laser additive manufacturing technology boasts numerous advantages in precision and the ability to fabricate complex materials, leading to its widespread application in key fields such as aerospace. However, as additive manufacturing technology evolves towards intelligent manufacturing and industrial applications, it also faces several challenges. Currently, the number of lasers is increasing, and the formed sizes are also growing, highlighting the issue of consistency across different laser processing systems. Even within the same laser processing system, the use of f-θ lasers in additive manufacturing results in inconsistent laser spot sizes across different areas, leading to variations in laser energy deposition during the additive process. Particularly concerning are the inconsistent laser morphology and spot size at the edges and interior of the formed area, resulting in inconsistent laser energy densities—a crucial factor in determining the laser forming process. Existing additive manufacturing technologies do not consider the inconsistency of laser spot sizes across different regions, instead employing uniform process parameters at the same structural location. This poses a challenge to the consistency of the forming process, hindering quality control in additive manufacturing. Summary of the Invention

[0004] To address the aforementioned technical issues, this invention provides a method for adaptively correcting process parameters within the printing area based on the shape of the light spot and the shape of the part, thereby significantly improving print quality consistency and print success rate while reducing printing costs.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0006] An adaptive printing method includes the following steps:

[0007] Step 1: Divide the print area into pixels to form independent regions, with the center coordinates of each region being (x, y, y). i ,y i ) or equivalent center coordinates are (xi ,y i );

[0008] Step 2: Import the slice model of the part to be printed, and set the corresponding process parameters according to the material type and structural characteristics, including laser power, scanning speed and track spacing, etc.

[0009] Step 3: Identification of the sliced ​​areas of the printed part: The sliced ​​areas of the printed part are identified using slice model analysis and geometric calculation methods;

[0010] Step 4: Segmentation of the printed part slice area: The slice area of ​​the printed part is segmented based on the pixelation of the printing area, that is, the printing area of ​​the printed part slice that falls into the above-mentioned identification area is pixelated.

[0011] Step 5: Refinement of process parameters: The process parameters of each area of ​​the part slice can be independently and freely set and defined based on the pixelation of the printing area, or corrected by adaptive coefficients based on the part features, or corrected by adaptive coefficients based on the temperature information collected by laser coaxial temperature measurement.

[0012] Step 6: Print the parts according to the adaptive coefficient correction rules in Step 5 for the segmented parts slice area.

[0013] Step 7: Repeat steps 2-6 to complete the printing of all slice layers of the model.

[0014] In step 2 of this invention, different material types and structures will result in different process parameters, which can be set according to the manufacturer's standard process parameters.

[0015] According to an embodiment of the present invention, in step 1, the region can be a rectangle (a×b) or an annulus centered on the center of the galvanometer (see reference). Figure 4 It can also be other custom shapes.

[0016] In some implementations, the number of annulus rings centered on the galvanometer and the width of each annulus ring can be freely defined.

[0017] According to an embodiment of the present invention, in step 3, the printed part slicing area includes, but is not limited to, at least one of the edge area, center area, support area, large overhang area and thin-walled area.

[0018] According to an embodiment of the present invention, step 3, the method for identifying the sliced ​​area of ​​the printed part, includes the following steps:

[0019] ① Edge region identification: Based on the contour (the actual outer contour of the part) composed of dense line segments in the slice layer, an additional envelope contour line is formed by offsetting it into the actual outer contour of the part by setting an extension distance (e.g., 1mm). The extension distance refers to the horizontal distance between the envelope contour line and the actual outer contour of the printed part, such as offset 1mm. All areas falling within the range of the actual outer contour of the part and the envelope contour line are marked as edge regions.

[0020] ②Central region identification: The solid area of ​​the part other than the edge area is regarded as the central region;

[0021] ③ Support area identification: Slicing software or support generators (such as Magics, JewelCAD, etc.) usually output the path of the support structure; identify all scan path areas that fall on the support generator and extend them to a certain height (such as 2 to 5 layers in the z direction) and mark them as support areas;

[0022] ④ Identification of large overhang areas: Compare each layer with the outline of the previous layer to identify areas where the overhang distance (the distance the horizontal overhang extends compared to the outline of the previous layer) exceeds a threshold (e.g., the overhang distance exceeds 1mm without support); use normal angle analysis (e.g., normal angle > 45°) to determine whether it is a large overhang area; the normal angle is the angle between the line connecting the edges of the upper and lower layers and the vertical direction;

[0023] ⑤ Thin-walled region identification: Use AABB bounding boxes to perform geometric analysis on STL / slice data; mark all structural regions with a thickness less than 0.8mm as thin-walled regions.

[0024] According to an embodiment of the present invention, in step 3, if the printed part slice area is simultaneously identified as a large overhang area and an edge area, then the area is determined to be a large overhang area based on the priority of the large overhang area being higher than that of the edge area.

[0025] According to an embodiment of the present invention, in step 5, the method for adaptive coefficient correction based on laser power density is as follows: based on the difference in laser energy density of independent regions formed by pixelation within the printing area, a laser energy density correction coefficient array based on independent regions is formed; specifically, the coefficient of the central region is used as a reference, and the coefficients of the remaining independent regions are normalized.

[0026] According to an exemplary embodiment of the present invention, the energy density or light intensity at the center of the printed area is a (W / cm²). 2 The energy density or light intensity of another independent region is b (W / cm²). 2 If ), then the adaptive correction coefficient for this independent region is b / a.

[0027] According to an embodiment of the present invention, in step 5, the process parameters for adaptive coefficient correction include: laser power, scanning speed, and channel spacing, etc.

[0028] According to an embodiment of the present invention, in step 5, the adaptive coefficient correction process parameters based on laser power density can be independently and freely set and defined along with the process parameters based on the pixelated segmentation region of the printing area, or the adaptive coefficient correction process parameters based on part features can work simultaneously.

[0029] According to an embodiment of the present invention, in step 5, the definition of independently and freely setting the process parameters of the pixelated segmentation area of ​​the printing area is to freely set the key process parameters (including laser power, scanning speed, and track spacing) of different pixelated areas based on experience or scientific research needs.

[0030] According to an embodiment of the present invention, in step 5, the adaptive coefficient process parameter is corrected based on the part features: the part features include the aforementioned edge region, center region, support region, large overhang region and thin-walled region;

[0031] An adaptive coefficient is set for each region. The coefficient is determined based on the size of the region. Generally, edge regions, central regions, support regions, and large overhang regions tend to use low-energy additive manufacturing, and their adaptive coefficients are the same or different, and are independently less than 1. For example, the adaptive coefficients of each region are independently 0.6 ≤ adaptive coefficient < 1. Thin-walled regions generally tend to use even lower energy, and their adaptive coefficients are even smaller, for example, adaptive coefficient < 0.7.

[0032] According to an exemplary embodiment of the present invention, in step 5, the adaptive coefficients of each region are set: the adaptive coefficient Xs of the edge region (generally 0.9), the adaptive coefficient Xc of the center region (generally 1.0), the adaptive coefficient Xs of the support region (generally 0.8), the adaptive coefficient Xb of the large overhang region (generally 0.6), and the adaptive coefficient Xt of the thin-walled region (generally 0.6).

[0033] According to an embodiment of the present invention, in step 5, the method of adaptive coefficient correction based on laser power density means that when the laser scans to the above-mentioned regions, the laser power is automatically set to standard power ÷ adaptive correction coefficient, or the scanning speed is automatically set to standard scanning speed × adaptive correction coefficient, or the channel spacing is automatically set to standard channel spacing × adaptive correction coefficient.

[0034] According to an exemplary embodiment of the present invention, the adaptive correction method for the process parameters of each slice region of the segmented printed part is as follows:

[0035] ① Adaptive laser power correction: When the laser scans into a pre-defined independent area on the printed surface, the laser power of that area is set to: base laser power × correction coefficient for that independent area;

[0036] ② Adaptive scanning speed correction: When the laser scans into a pre-defined independent area on the printed surface, the scanning speed of that area is set to: base scanning speed ÷ correction coefficient for that independent area;

[0037] ③ Adaptive correction of track spacing: When the laser scans into a certain independent area divided on the printing surface, the scanning speed of that area is set to: reference track spacing ÷ correction coefficient of that independent area.

[0038] According to an embodiment of the present invention, step 5, the method for adaptive coefficient correction based on the temperature information acquired by laser coaxial thermometry, includes the following steps:

[0039] ① First, a target temperature T0 is preset;

[0040] ② When the laser is working, a temperature information T1 (the temperature of the point scanned by the laser in real time) is acquired in a certain independent area. At this time, the temperature adaptive correction coefficient of the independent area can be obtained as T1 / T0.

[0041] The adaptive correction method for the process parameters of each slice region of the segmented printed part is as follows:

[0042] ①Laser power adaptive correction: When the laser scans into a certain independent area divided on the printing surface, the laser power of that area is set to: reference laser power ÷ temperature adaptive correction coefficient of that independent area;

[0043] ② Adaptive scanning speed correction: When the laser scans into a pre-defined independent area on the printed surface, the scanning speed of that area is set to: base scanning speed × temperature adaptive correction coefficient of that independent area.

[0044] The beneficial effects of this invention are as follows: This invention can adaptively or finely modify the laser processing parameters according to different forming positions based on the different geometric shapes of the parts and the inherent differences in the spot size within the printing laser f-θ laser system. This significantly improves the manufacturability, ensures the consistency of forming quality, enhances forming stability and forming quality and printing success rate, and further breaks through the geometric limits of laser additive manufacturing. This invention has the ability to finely control process parameters. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the division within the printing area in Example 1;

[0046] Figure 2This is a schematic diagram of the refined adaptive process method based on part features in Example 2; where: 1, envelope contour; 2, envelope region.

[0047] Figure 3 This is a schematic diagram of the free refinement adaptive process method for dividing printed parts in Example 3; where: 3, outline.

[0048] Figure 4 This is a schematic diagram of a ring structure centered on the center of the galvanometer. Detailed Implementation

[0049] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0050] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0051] Example 1

[0052] A refined adaptive process method based on laser power density printing area segmentation, taking a cylindrical part made of titanium alloy TC4 as an example, specifically includes the following steps:

[0053] (1) As Figure 1 As shown, the print area is divided into independent small regions, and the center coordinates of each region are (x, y, y). i ,y i );

[0054] (2) The laser spot energy density of each region is measured using a laser spot analyzer to form a matrix of laser spot energy density values;

[0055] Using the laser energy density at the center (x6, y6) of the printed area as a benchmark, the laser energy density of other areas (all areas within the printed area except the center benchmark) is normalized to form a matrix-like coefficient array, such as:

[0056] x1 <![CDATA[x2]]> <![CDATA[x3]]> <![CDATA[x4]]> <![CDATA[x5]]> <![CDATA[x6]]> <![CDATA[x7]]> <![CDATA[x8]]> <![CDATA[x9]]> <![CDATA[x 10 ]]> <![CDATA[x 11 ]]> <![CDATA[y1]]> 0.906 0.927 0.939 0.959 0.979 0.981 0.975 0.960 0.951 0.930 0.909 <![CDATA[y2]]> 0.924 0.931 0.941 0.957 0.976 0.982 0.972 0.955 0.946 0.935 0.930 <![CDATA[y3]]> 0.945 0.945 0.956 0.079 0.981 0.988 0.979 0.971 0.950 0.947 0.949 <![CDATA[y4]]> 0.960 0.954 0.979 0.980 0.989 0.989 0.982 0.090 0.970 0.956 0.958 <![CDATA[y5]]> 0.980 0.982 0.985 0.987 0.992 0.994 0.993 0.980 0.981 0.978 0.978 <![CDATA[y6]]> 0.981 0.982 0.980 0.986 0.997 1 0.996 0.989 0.979 0.979 0.983 <![CDATA[y7]]> 0.972 0.973 0.981 0.982 0.993 0.996 0.990 0.986 0.982 0.969 0.979 <![CDATA[y8]]> 0.952 0.953 0.976 0.980 0.984 0.983 0.984 0.981 0.971 0.959 0.,964 <![CDATA[y9]]> 0.946 0.942 0.954 0.975 0.981 0.979 0.980 0.970 0.958 0.946 0.952 <![CDATA[y 10 ]]> 0.926 0.931 0.941 0.957 0.977 0.980 0.978 0.953 0.949 0.939 0.941 <![CDATA[y 11 ]]> 0.913 0.930 0.941 0.955 0.972 0.980 0.979 0.964 0.948 0.931 0.920

[0057] (3) Import the slice model of the hollow cylindrical part to be printed (generated by Magics software), and set the overall TC4 material standard process parameters: laser power of 160W, scanning speed of 0.8m / s, and track spacing of 0.1mm; set the contour parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm; set the support parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm; the standard process parameters were optimized by the inventor through a large number of process experiments;

[0058] (3) Identification of the sliced ​​area of ​​the printed part: Select the refined adaptive process method to only identify the outline area of ​​the part and no longer identify other areas;

[0059] The contour region identification method is as follows: the actual contour boundary of the part composed of slice contour line segments is offset by 1mm. The other contour formed by this offset is the contour region of the part.

[0060] (4) Segmentation of the printed part slice area: The slice area of ​​the printed part is segmented based on the pixelation of the printing area, that is, the printing area of ​​the printed part slice that falls into the above-mentioned identification area is pixelated.

[0061] (5) The refined adaptive segmentation method is selected as follows: the adaptive process control parameter is selected as the adaptive coefficient correction based on the laser power density;

[0062] Based on the different areas (x) where the sliced ​​parts fall on the printing surface i ,y j Multiply the laser power of this region by the correction factor for the corresponding region. For example, the laser power of the part falling into region (x1,y1) is the standard laser power ÷ 0.906; the laser power of the part falling into region (x1,y2) is the standard laser power ÷ 0.924; and the laser power of the part falling into region (x1,y3) is the standard laser power ÷ 0.945.

[0063] (6) Based on the above rules, adjust the process parameters of other different areas to complete the printing of the parts.

[0064] Example 2

[0065] A refined adaptive process method based on part features, taking TC4 material parts as an example, specifically includes the following steps:

[0066] (1) As Figure 2 As shown, the print area is divided into independent small regions, and the center coordinates of each region are (x, y, y). i ,y i );

[0067] (2) The laser spot energy density of each region is measured using a laser spot analyzer to form a matrix of laser spot energy density values;

[0068] Using the laser energy density at the center (x6, y6) of the printing area as a benchmark, the laser energy density of other areas (all areas within the printing area except the center benchmark) is normalized to form a matrix-like coefficient array.

[0069] (3) Import the slice model of the printed part (generated by Magics software), and set the overall standard process parameters: laser power of 160W, scanning speed of 0.8m / s, and track spacing of 0.1mm; set the contour parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm; set the support parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm.

[0070] (4) Identification of the sliced ​​areas of the printed parts: The sliced ​​areas of the printed parts are identified using slice model analysis and geometric calculation methods. The specific methods are as follows:

[0071] Edge region identification: Based on the contour composed of dense line segments in the slice layer, calculate the area within 1mm of the actual outer contour edge of the part for each layer contour to obtain the envelope boundary; mark all areas falling within this extended distance range as edge regions;

[0072] Center region identification: The part entity area other than the edge area is regarded as the center region;

[0073] Support area identification: When importing part parameters, the printed part and the support part are imported at the same time. Therefore, the part position corresponding to the support position at the same coordinate point is marked as the support area.

[0074] Large overhang area identification: Compare the outline of each layer with the layer above to identify areas with an unsupported overhang distance of more than 2mm; use normal angle analysis (e.g., normal angle > 45°) to determine whether it is a large overhang area;

[0075] Thin-walled region identification: AABB bounding boxes are used for geometric analysis of STL / slice data; all structural regions with a thickness less than a certain value (e.g., 0.8 mm) are marked as thin-walled regions.

[0076] (5) Segmentation of the printed part slice area: The slice area of ​​the printed part is segmented based on the pixelation of the printing area, that is, the printing area of ​​the printed part slice that falls into the above-mentioned identification area is pixelated.

[0077] (6) Refined correction of process parameters: a refined adaptive process method based on part features; part features include edge regions, center regions, support regions, large overhang regions and thin-walled regions;

[0078] The edge area width is set to 2mm, and the process parameters are: laser power 100W, scanning speed 0.4m / s, and track spacing 0.1mm.

[0079] Set the parameters of the central region to the standard process parameters;

[0080] Set the support region parameters and edge region parameters to be the same;

[0081] The parameters for the large overhang area are set as follows: laser power 80W, scanning speed 0.4m / s, and track spacing 0.1mm;

[0082] The parameters for the thin-walled region are set as follows: laser power 80W, scanning speed 0.6m / s, and track spacing 0.1mm;

[0083] (7) Print the parts according to the different process parameters of the different areas set above, until printing is completed.

[0084] Example 3

[0085] The printed parts undergo adaptive coefficient correction based on temperature information acquired by laser coaxial thermometry, including the following steps:

[0086] (1) Divide the printed area into pixels to form independent regions, with the center coordinates of each region being (x, y). i ,y i ) or equivalent center coordinates are (x i ,y i );

[0087] (2) Import the slice model of the printed part (generated by Magics software), and set the overall standard process parameters: laser power of 160W, scanning speed of 0.8m / s, and track spacing of 0.1mm; set the contour parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm; set the support parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm.

[0088] (3) The refined adaptive segmentation method is selected as follows: an adaptive coefficient correction method based on the temperature information collected by laser coaxial thermometry (when this method is selected, regional feature recognition is not considered).

[0089] (4) Set the target temperature to 1880℃ and set the correction parameter to laser power;

[0090] (5) Printing: The temperature is 2300℃ in real time by coaxial temperature measurement, and the correction coefficient is 2300 / 1880=1.223. Then the laser power is immediately corrected to 160÷1.223=130.78W. The printing is completed in this way.

[0091] Example 4

[0092] A flexible and adaptive process method for dividing printed parts includes the following steps:

[0093] (1) As Figure 3 As shown, import the slice model of the part to be printed (generated by Magics software). The model has a total of 3200 layers. Set the standard process parameters for the solid: laser power of 160W, scanning speed of 0.8m / s, and track spacing of 0.1mm; set the contour parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm; set the support parameters: laser power of 160W, scanning speed of 1.6m / s, and track spacing of 0.1mm.

[0094] (2) The selected refined adaptive segmentation method is: the free refined adaptive process method for printing part segmentation (i.e., grid segmentation);

[0095] (3) Set the number of regions to be divided within the print area. Divide the area into 10mm×10mm regions using a grid method to form a certain number of regions. The center coordinates of each region are (x... i ,y j );

[0096] Set a certain number of layers, 160-1090 layers, and select the segmentation area near the edge of the part outline by mouse (the selected area is the area where the mouse click coordinates fall into the segmentation area). Set the process parameters: laser power is 140W, scanning speed is 0.8m / s, and track spacing is 0.1mm; other segmentation areas far from the edge use standard process parameters.

[0097] Set up another certain number of layers (1091-2100). Select the segmentation area near the edge of the part outline using the mouse (the selected area is defined by the mouse click coordinates falling within the segmentation area). Set the process parameters for the selected area: laser power 135W, scanning speed 0.8m / s, and track spacing 0.1mm. Use standard process parameters for other segmentation areas far from the edge.

[0098] Standard process parameters are used for floors 1-159 and 2101-3100.

[0099] (4) Print the parts according to the different process parameters set for different areas above.

[0100] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive printing method, characterized in that, Includes the following steps: Step 1: Divide the print area into pixels to form independent regions, with the center coordinates of each region being (x, y, y). i ,y i ) or equivalent center coordinates are (x i ,y i ); Step 2: Import the slice model of the part to be printed, and set the corresponding process parameters, including laser power, scanning speed and track spacing, etc. Step 3: Identification of the sliced ​​areas of the printed part: The sliced ​​areas of the printed part are identified using slice model analysis and geometric calculation methods; Step 4: Segmentation of the printed part slice area: The slice area of ​​the printed part is segmented based on the pixelation of the printing area, that is, the printing area of ​​the printed part slice that falls into the above-mentioned identification area is pixelated. Step 5: Refinement of process parameters: The process parameters of each area of ​​the part slice can be independently and freely set and defined based on the pixelation of the printing area, or corrected by adaptive coefficients based on the part features, or corrected by adaptive coefficients based on the temperature information collected by laser coaxial temperature measurement. Step 6: Print the parts according to the adaptive coefficient correction rules in Step 5 for the segmented parts slice area. Step 7: Repeat steps 2-6 to complete the printing of all slice layers of the model.

2. The adaptive printing method as described in claim 1, characterized in that, In step 5, the method for adaptive coefficient correction based on laser power density is as follows: based on the difference in laser energy density of independent regions formed by pixelation within the printed area, a laser energy density correction coefficient array based on independent regions is formed. Preferably, the coefficients of the remaining independent regions are normalized based on the coefficient of the central region; for example, the energy density or light intensity at the center of the printed area is a (W / cm²). 2 The energy density or light intensity of another independent region is b (W / cm²). 2 If ), then the adaptive correction coefficient for this independent region is b / a.

3. The adaptive printing method as described in claim 1, characterized in that, In step 3, the printed part slicing area includes, but is not limited to, at least one of the edge area, center area, support area, large overhang area, and thin-walled area.

4. The adaptive printing method as described in claim 3, characterized in that, Step 3, the method for identifying the sliced ​​area of ​​the printed part, includes the following steps: ① Edge region identification: Based on the contour (actual contour of the part) composed of dense line segments in the slice layer, an additional envelope contour line is formed by offsetting the actual outer contour of the part by setting an extension distance (e.g., 1mm) (the extension distance refers to the horizontal distance between the envelope contour line and the actual outer contour of the printed part, such as offset 1mm); all areas falling within the range of the actual outer contour of the part and the envelope contour line are marked as edge regions. ②Central region identification: The solid area of ​​the part other than the edge area is regarded as the central region; ③ Support area identification: Slicing software or support generators usually output the path of the support structure; identify all scan path areas that fall on the support generator and extend them to a certain height (e.g., 2 to 5 layers in the z direction) and mark them as support areas; ④ Identification of large overhang areas: Compare each layer with the outline of the previous layer to identify areas where the overhang distance (the distance the horizontal overhang extends compared to the outline of the previous layer) exceeds a threshold (e.g., the overhang distance exceeds 1mm without support); use normal angle analysis (e.g., normal angle > 45°) to determine whether it is a large overhang area; the normal angle is the angle between the line connecting the edges of the upper and lower layers and the vertical direction; ⑤ Thin-walled region identification: Use AABB bounding boxes to perform geometric analysis on STL / slice data; mark all structural regions with a thickness less than 0.8mm as thin-walled regions.

5. The adaptive printing method as described in claim 3 or 4, characterized in that, In step 3, if the sliced ​​area of ​​the printed part is simultaneously identified as a large overhang area and an edge area, then the area is determined to be a large overhang area because the large overhang area has a higher priority than the edge area.

6. The adaptive printing method according to any one of claims 1-5, characterized in that, In step 5, the process parameters for adaptive coefficient correction include: laser power, scanning speed, and channel spacing, etc. And / or, in step 5, the adaptive coefficient correction process parameters based on laser power density can be independently and freely set and defined along with the process parameters based on the pixelated segmentation region of the printing area, or the adaptive coefficient correction process parameters based on part features can work simultaneously.

7. The adaptive printing method according to any one of claims 1-5, characterized in that, In step 5, the definition of independently and freely setting the process parameters of the pixelated segmentation area of ​​the printing sheet is to freely set the key process parameters (including laser power, scanning speed, and track spacing) of different pixelated areas according to experience or scientific research needs. And / or, in step 5, the adaptive coefficient process parameter correction is based on the part features: the part features include the aforementioned edge region, center region, support region, large overhang region and thin-walled region; Set the adaptive coefficients for each region: the adaptive coefficients for the edge region, center region, support region, and large overhang region are the same or different, and are independently less than 1. For example, the adaptive coefficients for each region are independently 0.6 ≤ adaptive coefficient < 1; for thin-walled regions, the adaptive coefficient is < 0.

7.

8. The adaptive printing method as described in claim 7, characterized in that, In step 5, the method of adaptive coefficient correction based on laser power density means that when the laser scans to the above-mentioned regions, the laser power is automatically set to standard power ÷ adaptive correction coefficient, or the scanning speed is automatically set to standard scanning speed × adaptive correction coefficient, or the channel spacing is automatically set to standard channel spacing × adaptive correction coefficient.

9. The adaptive printing method according to any one of claims 1-5, characterized in that, The adaptive correction method for the process parameters of each slice region of the segmented printed part is as follows: ① Adaptive laser power correction: When the laser scans into a pre-defined independent area on the printed surface, the laser power of that area is set to: base laser power × correction coefficient for that independent area; ② Adaptive scanning speed correction: When the laser scans into a pre-defined independent area on the printed surface, the scanning speed of that area is set to: base scanning speed ÷ correction coefficient for that independent area; ③ Adaptive correction of track spacing: When the laser scans into a certain independent area divided on the printing surface, the scanning speed of that area is set to: reference track spacing ÷ correction coefficient of that independent area.

10. The adaptive printing method according to any one of claims 1-5, characterized in that, Step 5, the method for adaptive coefficient correction based on the temperature information acquired by laser coaxial thermometry, includes the following steps: ① First, a target temperature T0 is preset; ② When the laser is working, a temperature information T1 (the temperature of the point scanned by the laser in real time) is acquired in a certain independent area. At this time, the temperature adaptive correction coefficient of the independent area can be obtained as T1 / T0. The adaptive correction method for the process parameters of each slice region of the segmented printed part is as follows: ①Laser power adaptive correction: When the laser scans into a certain independent area divided on the printing surface, the laser power of that area is set to: reference laser power ÷ temperature adaptive correction coefficient of that independent area; ② Adaptive scanning speed correction: When the laser scans into a pre-defined independent area on the printed surface, the scanning speed of that area is set to: base scanning speed × temperature adaptive correction coefficient of that independent area.

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