Laser scanning method based on molten pool monitoring, additive manufacturing equipment, and computer storage media

Abstract

A laser scanning method, additive manufacturing equipment, and computer storage medium based on molten pool monitoring are disclosed. The scanning method includes: slicing a model of the part to be printed to obtain the contour cross-section of each layer; scanning the contour cross-section of each layer using several preset fill vectors in a preset direction; analyzing the heat of the formed contour cross-section of each layer; when an overheated area with heat exceeding a threshold exists in the contour cross-section of a certain layer, the scanning path of the contour cross-section of the next layer is determined as follows: projecting the overheated area of ​​the current layer onto the contour cross-section of the next layer to obtain the area to be processed; extracting all fill vectors passing through the area to be processed and breaking them, with the breakpoint located within the area to be processed and its boundary. This invention, by changing the scanning path and scanning energy of the fill vectors, homogenizes the heat in the overheated area, thereby avoiding heat concentration in the overheated area and effectively improving the success rate and surface quality of the part to be printed.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a laser scanning method based on molten pool monitoring, additive manufacturing equipment, and computer storage medium. Background Technology

[0002] Additive manufacturing technology is an advanced manufacturing technology with distinctive characteristics such as digital manufacturing, high flexibility and adaptability, direct CAD model-driven operation, speed, and a wide variety of material types. Because it is not limited by the complexity of part shapes and does not require any tooling or molds, its application range is very wide. Selective Laser Sintering (SLS) is one of the rapidly developing additive manufacturing technologies in recent years. It uses powder materials as raw materials and employs a laser to scan the cross-section of a three-dimensional solid layer by layer to complete the prototype manufacturing. Its basic working process is as follows: a powder feeding device delivers a certain amount of powder to the working platform surface; a powder spreading device spreads a layer of powder material evenly on the bottom plate of the working cavity or the upper surface of the already formed part; a laser galvanometer system controls the laser to scan the solid powder layer according to the cross-sectional contour of the layer with an approximately constant spot size and beam energy, causing the powder to melt and bond with the already formed part below; after one layer of cross-section is sintered, the working platform lowers by one layer thickness, and the powder spreading device spreads another layer of uniform and dense powder on top, and a new layer of cross-section is scanned and sintered. This process is repeated for several layers until the entire prototype manufacturing is completed.

[0003] Existing laser scanning methods primarily generate fill vectors within a contour, starting and ending at the contour. These methods include parallel line scanning, contour equidistant line scanning, and a combination of both. Due to the characteristics of both the laser scanning method and the workpiece being printed, these existing laser scanning methods are prone to heat concentration in localized areas, leading to localized overheating. This can cause warping and deformation, affecting the printing quality of the workpiece. In severe cases, it can disrupt the forming process, resulting in workpiece scrap and increased product costs. Summary of the Invention

[0004] In view of this, the present invention provides a laser scanning method based on melt pool monitoring, an additive manufacturing device, and a computer storage medium. This laser scanning method based on melt pool monitoring can uniformly distribute the heat in the overheated area by changing the scanning path and scanning energy of the fill vector, thereby avoiding further heat concentration in the overheated area and preventing warping during the printing process.

[0005] To achieve the above objectives, the present invention provides a laser scanning method based on molten pool monitoring, comprising the following steps:

[0006] The model of the part to be printed is sliced ​​to obtain the contour section of each layer;

[0007] For the contour section of each layer, several preset fill vectors are used to scan in a preset direction, and the energy of the preset fill vector is a first preset energy value;

[0008] Based on molten pool monitoring, the heat of each formed profile section is analyzed. When an overheated area with heat exceeding a threshold exists in the profile section of a certain layer, the scanning path and scanning energy of the next layer are re-determined in the following manner:

[0009] Project the overheated area of ​​the current layer onto the contour section of the next layer to obtain the area to be processed. Extract all filling vectors passing through the area to be processed and break them. The break points are located within the area to be processed and its boundaries.

[0010] The energy of the filling vector in the area to be processed is controlled to a second preset energy value, which is less than the first preset energy value.

[0011] As a further preferred embodiment of the present invention, the contour section of each layer is scanned using several mutually parallel preset fill vectors.

[0012] As a further preferred embodiment of the present invention, the contour section comprises a plurality of closed polygons, and at least one polygon in the next layer redefines the scanning path and scanning energy in the following manner:

[0013] The overheated region of the current layer is projected onto at least one polygon of the next layer to obtain the region to be processed. The region to be processed includes at least one closed virtual region. When the virtual region coincides with the corresponding polygon, the breakpoint in the virtual region is the starting point of all fill vectors in the virtual region. When the virtual region is a local region of the corresponding polygon, the breakpoint in the virtual region is the ending point of all fill vectors in the virtual region.

[0014] As a further preferred embodiment of the present invention, when the virtual region is a local region of the corresponding polygon, the next layer of the polygon redetermines the scanning path and scanning energy in the following manner:

[0015] Extract all fill vectors passing through the virtual region and break them. The break point of each fill vector includes at least one intersection point with the virtual region and the midpoint of the fill vector within the virtual region.

[0016] Control at least one interrupted fill vector outside the virtual region of the polygon to scan according to a preset direction and a first preset energy value; control at least one interrupted fill vector within the virtual region to keep its direction unchanged or rotate 180 degrees so that the endpoint of all interrupted fill vectors within the virtual region is the midpoint of the fill vector within the virtual region, and control the energy of all interrupted fill vectors within the virtual region to a second preset energy value.

[0017] As a further preferred embodiment of the present invention, when the virtual region coincides with the corresponding polygon, the next layer of the polygon redetermines the scanning path and scanning energy in the following manner:

[0018] Obtain two quarter-division points near the contour boundary for each fill vector within the polygon, and denot them as the first division point and the second division point, respectively.

[0019] Connect the first division points of all fill vectors on one side in sequence to form the first line, and connect the second division points of all fill vectors on the other side in sequence to form the second line. Then extend the first line and the second line to both ends and intersect to obtain a closed random area.

[0020] All fill vectors are broken, and the break point of each fill vector is randomly located on the fill vector within a random region;

[0021] The direction of the interrupted fill vector is kept unchanged or rotated 180 degrees so that the starting point of all interrupted fill vectors is the interruption point, and the energy of all interrupted fill vectors is controlled to the second preset energy value.

[0022] As a further preferred embodiment of the present invention, the second preset energy value is a constant value Y, and it satisfies the following formula:

[0023] Y = αX + β, where α and β are coefficients, and X is the value at which the monitored heat of the molten pool in the current layer exceeds the threshold.

[0024] As a further preferred embodiment of the present invention, the second preset energy value is a variable value, and the second preset energy value changes gradually or stepwise during the scanning process from the starting point to the ending point of the filling vector.

[0025] As a further preferred embodiment of the present invention, when the area of ​​the virtual region is less than half of the area of ​​the corresponding polygon, the second preset energy value changes in a stepwise manner; when the virtual region is greater than or equal to half of the area of ​​the corresponding polygon, the second preset energy value changes gradually.

[0026] The present invention also provides an additive manufacturing apparatus, comprising:

[0027] The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes these computer instructions to perform the laser scanning method based on molten pool monitoring described above.

[0028] The present invention also provides a computer-readable storage medium storing computer instructions for causing the computer to execute the laser scanning method based on melt pool monitoring described in any of the preceding claims.

[0029] The present invention relates to a laser scanning method, additive manufacturing equipment, and computer storage medium based on melt pool monitoring. The laser scanning method includes: slicing a model of the workpiece to be printed to obtain the contour cross-section of each layer; scanning the contour cross-section of each layer using several preset fill vectors in a preset direction, wherein the energy of the preset fill vectors is a first preset energy value; and analyzing the heat of each formed contour cross-section based on melt pool monitoring. When an overheated area exceeding a threshold exists in the contour cross-section of a certain layer, the scanning path and scanning energy of the contour cross-section of the next layer are re-determined in the following manner: projecting the overheated area of ​​the current layer onto the next layer. The contour section is used to obtain the area to be processed. All filling vectors passing through the area to be processed are extracted and broken, and the break points are located within the area to be processed and its boundary. The energy of the filling vectors within the area to be processed is controlled to a second preset energy value, which is less than the first preset energy value. This allows the laser scanning method of the present invention to uniformize the heat in the overheated area by changing the scanning path and scanning energy of the filling vectors, thereby avoiding further heat concentration in the overheated area, preventing warping during printing, helping to reduce crack initiation, and thus effectively improving the success rate, surface quality and performance of the printed parts. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a flowchart of an embodiment of the laser scanning method based on molten pool monitoring provided by the present invention;

[0032] Figure 2 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 1 ;

[0033] Figure 3 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 2 ;

[0034] Figure 4 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 3 ;

[0035] Figure 5 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 4 ;

[0036] Figure 6 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 5 ;

[0037] Figure 7 This is the first embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 6 ;

[0038] Figure 8 This is the second embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 1 ;

[0039] Figure 9 This is the second embodiment of the laser scanning method based on molten pool monitoring provided by the present invention. Figure 2 . Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] like Figure 1 As shown, the present invention provides a laser scanning method based on molten pool monitoring, comprising the following steps:

[0042] Step S1: Slice the model of the part to be printed to obtain the contour section of each layer;

[0043] Step S2: Scan the contour section of each layer using several preset fill vectors in a preset direction. The energy of the preset fill vectors is a first preset energy value. Specifically, the contour section of each layer is scanned using several mutually parallel preset fill vectors. In this application, the energy of the fill vectors is composed of parameters such as power, speed, spacing, and jump delay. The preset direction in this step can be predetermined by the designer, for example, scanning can be performed from left to right, and then from right to left.

[0044] Step S3: Based on melt pool monitoring, analyze the heat of each layer of formed contour cross-section. When there is an overheated area in the contour cross-section of a certain layer where the heat exceeds the threshold, the scanning path and scanning energy of the next layer of contour cross-section are re-determined in the following manner: It should be noted that the heat analysis of each layer of formed contour cross-section based on melt pool monitoring in this step is an existing technology in this field. For example, the heat value of each layer of formed contour cross-section can be obtained in real time through melt pool monitoring, and it can be analyzed to determine whether it exceeds the threshold. This threshold can be determined by the designer based on the material type of the part to be printed, equipment parameters, printing parameters, etc.

[0045] Step S4: Project the overheated area of ​​the current layer onto the contour section of the next layer to obtain the area to be processed. Extract all filling vectors passing through the area to be processed and break them. The break points are located within the area to be processed and its boundaries.

[0046] Step S5: Control the energy of the filling vector in the area to be processed to a second preset energy value, where the second preset energy value is less than the first preset energy value.

[0047] It is understood that when there is no overheated area with heat exceeding the threshold in the profile section of a certain layer in step S3, the profile section of the next layer can continue to be scanned with reference to the preset direction and the first preset energy value in step S2. In other words, the technical solution of the present invention is not activated.

[0048] In specific implementation, the contour section includes several closed polygons, and at least one polygon in the next layer redetermines the scanning path and scanning energy in the following manner:

[0049] The overheated region of the current layer is projected onto at least one polygon in the next layer to obtain the region to be processed. This region includes at least one closed virtual region. When the virtual region coincides with the corresponding polygon, the breakpoint within the virtual region is the starting point of all fill vectors within that virtual region; when the virtual region is a local region of the corresponding polygon, the breakpoint within the virtual region is the ending point of all fill vectors within that virtual region. In this application, the corresponding polygon refers to a polygon containing a virtual region. The region to be processed is divided into at least one closed virtual region based on whether the virtual regions are continuous or not. That is, the region to be processed is divided into one or more discontinuous closed virtual regions. Each polygon may contain at least one virtual region, and a virtual region can only be contained by one polygon.

[0050] It is understood that the above description only uses a single polygon as an example to illustrate how to redetermine the scan path and scan energy. Preferably, the scan strategy for other polygons can be implemented with reference to this polygon, but it is also possible to implement it without referring to it. This will not be repeated here.

[0051] Specifically, the scanning strategy differs depending on whether the virtual region partially or completely occupies its corresponding polygon, as explained below:

[0052] When the virtual region is a local region of the corresponding polygon, the next layer of the polygon redetermines the scan path and scan energy in the following manner:

[0053] Extract all fill vectors passing through the virtual region and break them. The break point of each fill vector includes at least one intersection point with the virtual region and the midpoint of the fill vector within the virtual region.

[0054] Control at least one interrupted fill vector outside the virtual region of the polygon to scan according to a preset direction and a first preset energy value; control at least one interrupted fill vector within the virtual region to keep its direction unchanged or rotate 180 degrees so that the endpoint of all interrupted fill vectors within the virtual region is the midpoint of the fill vector within the virtual region, and control the energy of all interrupted fill vectors within the virtual region to a second preset energy value.

[0055] When a virtual region coincides with a corresponding polygon, the next layer of that polygon redetermines the scan path and scan energy in the following manner:

[0056] Obtain two quarter-division points near the contour boundary for each fill vector within the polygon, and denot them as the first division point and the second division point, respectively.

[0057] Connect the first division points of all fill vectors on one side in sequence to form the first line, and connect the second division points of all fill vectors on the other side in sequence to form the second line. Then extend the first line and the second line to both ends and intersect to obtain a closed random area.

[0058] All fill vectors are broken, and the break point of each fill vector is randomly located on the fill vector within a random region;

[0059] The direction of the interrupted fill vector is kept unchanged or rotated 180 degrees so that the starting point of all interrupted fill vectors is the interruption point, and the energy of all interrupted fill vectors is controlled to the second preset energy value.

[0060] Similarly, the above only describes how to redetermine the scan path and scan energy using a single virtual region as an example. Likewise, the scan strategy for other virtual regions is executed in accordance with the strategy for this virtual region, and will not be repeated here.

[0061] Preferably, to further improve print quality, the second preset energy value is a constant value Y, and it satisfies the following formula:

[0062] Y = αX + β, where α and β are coefficients, and X is the value at which the monitored heat of the molten pool in the current layer exceeds the threshold. In practice, α can be determined by the designer based on the printing material, and β can be determined based on the actual printing parameters.

[0063] To ensure more uniform heat distribution in the overheated area and reduce the risk of warping in the high-risk area, the first preferred method is as follows: the second preset energy value is a variable value, and the second preset energy value changes gradually or stepwise during the scanning process from the start point to the end point of the fill vector. The second preferred method is as follows: when the overheated area is located inside the part to be printed, a low power can be used at the start point and a high power can be used at the end point to improve the heat distribution in the overheated area; when the overheated area is located at the edge of the part to be printed, a low power can be used at both the start point and the end point to make the heat distribution in the overheated area more uniform and reduce the risk of warping in the high-risk area.

[0064] More preferably, when the area of ​​the virtual region is less than half the area of ​​the corresponding polygon, the second preset energy value changes in a stepwise manner; when the virtual region is greater than or equal to half the area of ​​the corresponding polygon, the second preset energy value changes gradually. This can also make the heat distribution more uniform.

[0065] The present invention also provides an additive manufacturing apparatus, comprising:

[0066] The system includes a memory and a processor, which are interconnected. The memory stores computer instructions, and the processor executes these computer instructions to perform the laser scanning method based on molten pool monitoring as described in any of the above embodiments.

[0067] The present invention also provides a computer-readable storage medium storing computer instructions for causing the computer to execute the laser scanning method based on melt pool monitoring as described in any of the above embodiments.

[0068] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be specifically described below in the form of embodiments and in conjunction with the accompanying drawings.

[0069] Example 1

[0070] The laser scanning method based on molten pool monitoring in this embodiment includes the following steps:

[0071] Step 11: Slice the workpiece to be printed to obtain the contour section of each layer. This contour section may contain multiple polygons; in this embodiment, it only contains a single closed polygon, as shown below. Figure 2 As shown.

[0072] Step 12: For the contour section of each layer, scan using several mutually parallel preset fill vectors according to preset directions and a first preset energy value, such as... Figure 3 As shown.

[0073] Step 13: Based on the molten pool monitoring data, determine whether there is an overheated area in the current layer's profile section where the heat exceeds the threshold. If so, extract the area where the heat exceeds the threshold, generate the overheated area, and redetermine the scanning path and scanning energy of the next layer's profile section according to steps 14-17 below. Otherwise, the next layer's profile section follows the preset direction and first preset energy value determined in step 12 above. In other words, the scanning strategy and scanning energy of the next layer do not need to be changed.

[0074] Step 14: Project the overheated area of ​​the current layer onto the contour section of the next layer to obtain the area to be processed. This area to be processed is a closed virtual region, and the virtual contour is a local region of the corresponding polygon, such as... Figure 4 As shown, the rectangular area is a virtual area.

[0075] Step 15: Extract all fill amounts that have passed through the virtual region, such as... Figure 5 The dashed line portion is shown.

[0076] Step 16: Extract all fill vectors passing through the virtual region and break them. The break point of each fill vector includes the two intersection points with the virtual region and the midpoint of the fill vector within the virtual region, such as... Figure 6 As shown.

[0077] Step 17: Control at least one interrupted fill vector outside the virtual region of the polygon to scan according to a preset direction and a first preset energy value; control the direction of at least one interrupted fill vector within the virtual region to remain unchanged or rotate 180 degrees, so that the endpoint of all interrupted fill vectors within the virtual region is the midpoint of the fill vector within the virtual region, and control the energy of all interrupted fill vectors within the virtual region to a second preset energy value, where the second preset energy value is less than the first preset energy value, such as... Figure 7 As shown, during the scanning process, the second preset energy value changes for all fill vectors within the virtual region, exhibiting a step-like variation.

[0078] Step 18: Perform laser scanning according to the scanning path and scanning energy of the fill vectors of all the final obtained contour sections of each layer to form the part. It should be noted that the first contour section is the first layer, so it does not need to redetermine the scanning path and scanning energy. It can be scanned according to the fill vector in the preset direction and the first preset energy value.

[0079] Example 2

[0080] The laser scanning method based on molten pool monitoring in this embodiment includes the following steps:

[0081] Step 21: Slice the part to be printed to obtain the outline section of each layer. This outline section is a closed polygon.

[0082] Step 22: Scan the contour section of each layer using several mutually parallel preset fill vectors according to preset directions and the first preset energy value;

[0083] Step 23: Based on the molten pool monitoring data, determine whether there is an overheated area in the current layer's profile section where the heat exceeds the threshold. If so, extract the area where the heat exceeds the threshold, generate the overheated area, and redetermine the scanning path and scanning energy of the next layer's profile section according to steps 24-27 below. The next layer's profile section follows the preset direction and first preset energy value determined in step 12 above. In other words, the scanning strategy and scanning energy of the next layer do not need to be changed.

[0084] Step 24: Project the overheated area of ​​the current layer onto the contour section of the next layer to obtain the area to be processed. This area to be processed includes a closed virtual region, and the virtual contour completely coincides with the corresponding polygon, such as... Figure 8As shown, the virtual region is a polygon.

[0085] Step 25: Obtain two quarter-division points near the contour boundary for each fill vector within the polygon, and label them as the first and second division points respectively. Connect the first division points on one side of all fill vectors to form the first line, and connect the second division points on the other side of all fill vectors to form the second line. Extend the first and second lines to their intersections to obtain closed random regions, such as... Figure 8 The rugby ball area shown is a random area;

[0086] Step 26: Break all fill vectors, and the break point of each fill vector is randomly located on the fill vector within a random region, such as... Figure 9 The dots shown are the break points;

[0087] Step 27: Keep the direction of the interrupted fill vector unchanged or rotate it 180 degrees so that the starting point of all interrupted fill vectors is the break point, that is, the dot is the starting point of the fill vector and the arrow is the ending point of the fill vector, such as... Figure 9 As shown; and the energy of all interrupted fill vectors is controlled to a second preset energy value, which is less than the first preset energy value; and the second preset energy value changes gradually for all fill vectors within the virtual area during the scanning process.

[0088] Step 28: Perform laser scanning according to the scanning path and scanning energy of the fill vector of the contour section of all layers obtained in the end to form the part.

[0089] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A laser scanning method based on molten pool monitoring, characterized in that, Includes the following steps: The model of the part to be printed is sliced ​​to obtain the contour section of each layer; For the contour section of each layer, several preset fill vectors are used to scan in a preset direction, and the energy of the preset fill vector is a first preset energy value; Based on molten pool monitoring, the heat of each formed profile section is analyzed. When an overheated area with heat exceeding a threshold exists in the profile section of a certain layer, the scanning path and scanning energy of the next layer are re-determined in the following manner: Project the overheated area of ​​the current layer onto the contour section of the next layer to obtain the area to be processed. Extract all filling vectors passing through the area to be processed and break them, with the break points located within the area to be processed and its boundaries. The energy of the filling vector within the processing area is controlled to a second preset energy value, which is less than a first preset energy value; wherein... The profile section comprises several closed polygons, and at least one polygon in the next layer redefines the scan path and scan energy in the following manner: The overheated region of the current layer is projected onto at least one polygon of the next layer to obtain the region to be processed. The region to be processed includes at least one closed virtual region. When the virtual region coincides with the corresponding polygon, the breakpoint in the virtual region is the starting point of all fill vectors in the virtual region. When the virtual region is a local region of the corresponding polygon, the breakpoint in the virtual region is the ending point of all fill vectors in the virtual region.

2. The method according to claim 1, characterized in that, The contour section of each layer is scanned using several mutually parallel preset fill vectors.

3. The method according to claim 2, characterized in that, When the virtual region is a local region of the corresponding polygon, the next layer of the polygon redetermines the scan path and scan energy in the following manner: Extract all fill vectors passing through the virtual region and break them. The break point of each fill vector includes at least one intersection point with the virtual region and the midpoint of the fill vector within the virtual region. Control at least one interrupted fill vector outside the virtual region of the polygon to scan according to a preset direction and a first preset energy value; control at least one interrupted fill vector within the virtual region to keep its direction unchanged or rotate 180 degrees so that the endpoint of all interrupted fill vectors within the virtual region is the midpoint of the fill vector within the virtual region, and control the energy of all interrupted fill vectors within the virtual region to a second preset energy value.

4. The method according to claim 2, characterized in that, When a virtual region coincides with a corresponding polygon, the next layer of that polygon redetermines the scan path and scan energy in the following manner: Obtain two quarter-division points near the contour boundary for each fill vector within the polygon, and denot them as the first division point and the second division point, respectively. Connect the first division points of all fill vectors on one side in sequence to form the first line, and connect the second division points of all fill vectors on the other side in sequence to form the second line. Then extend the first line and the second line to both ends and intersect to obtain a closed random area. All fill vectors are broken, and the break point of each fill vector is randomly located on the fill vector within a random region; The direction of the interrupted fill vector is kept unchanged or rotated 180 degrees so that the starting point of all interrupted fill vectors is the interruption point, and the energy of all interrupted fill vectors is controlled to the second preset energy value.

5. The method according to any one of claims 1 to 4, characterized in that, The second preset energy value is a constant value Y, and it satisfies the following formula: Y = αX + β, where α and β are coefficients, and X is the value at which the monitored heat of the molten pool in the current layer exceeds the threshold.

6. The method according to any one of claims 1 to 4, characterized in that, The second preset energy value is a variable value, and during the scanning process from the start point to the end point of the filling vector, the second preset energy value changes gradually or stepwise.

7. The method according to claim 6, characterized in that, When the area of ​​the virtual region is less than half the area of ​​the corresponding polygon, the second preset energy value changes in a stepwise manner; when the virtual region is greater than or equal to half the area of ​​the corresponding polygon, the second preset energy value changes gradually.

8. An additive manufacturing apparatus, characterized in that, include: A memory and a processor are interconnected, the memory storing computer instructions, and the processor executing the computer instructions to perform the laser scanning method based on molten pool monitoring as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the laser scanning method based on melt pool monitoring as described in any one of claims 1-7.

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