A dual optical system wind-shielded sub-zone scanning method, device and additive manufacturing equipment

Abstract

A kind of double optical system sheltering subarea scanning method, device and additive manufacturing equipment, by obtaining all vertex coordinates in all cross-sectional profiles in each region in working area, and all intersection coordinates of cross-sectional profile and boundary line and subarea line, and all vertex coordinates and intersection coordinates are substituted into formula to obtain the total area of profile of each region;Arbitrarily select a group of two regions of opposite angle, by parallelly moving subarea line, so that the absolute value of the difference of the total area of profile of the selected two regions of opposite angle is minimum, at this time, the position of subarea line is the best position;Finally, according to the subarea line of best position, the four regions obtained by redividing are controlled, and double optical system is simultaneously parallel scanned on the above selected two regions of opposite angle;When the two regions are scanned, another group of corresponding two regions of opposite angle are simultaneously parallel scanned, the sheltering waiting time of double optical scanning system is reduced, and the sintering efficiency of workpiece is improved.

Description

Technical Field

[0001] This application relates to the field of additive manufacturing technology, and in particular to a dual-optical-system wind-avoidance zone scanning method, apparatus, and additive manufacturing equipment. 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] In the additive manufacturing process, as the size of printed workpieces increases, the number of lasers used also increases. However, while printing equipment with multiple lasers improves the production efficiency of additive manufacturing, the smoke and dust generated when different lasers sinter simultaneously may affect the sintering effect of other lasers.

[0004] To address the aforementioned technical issues, existing technologies generally employ a wind-avoidance zone scanning method. This method divides the area covered perpendicular to the wind field direction into equal parts based on the number of scanning systems arranged parallel to the wind field direction. This ensures that each scanning system scans only its assigned area at any given time, and that no other scanning systems in the upwind or downwind directions are present in the area assigned to each system simultaneously. After all scanning tasks within their assigned areas are completed, all systems switch to the next assigned scanning area.

[0005] While this wind-sheltered zone scanning method can mitigate the impact of smoke and dust during sintering, it has drawbacks. When the scanning tasks of each scanning system within its assigned scanning area are inconsistent, the system with fewer tasks may complete its scan first, waiting for the system with more tasks to finish before starting the next scan. This results in additional waiting time for multiple scanning systems, reducing work efficiency. Summary of the Invention

[0006] To address the aforementioned technical problems in the existing technology, this invention provides a dual-optical-system wind-avoidance zone scanning method, apparatus, and additive manufacturing equipment. This dual-optical-system wind-avoidance zone scanning method allocates wind-avoidance scanning tasks by summing the area of ​​the scanning cross-section in the working area to be scanned by the dual optical systems in the windward direction. This makes the time taken for different scanning systems to complete their assigned tasks as equal or similar as possible, thereby reducing the wind-avoidance waiting time of the dual optical systems and improving the sintering efficiency of the parts to be printed.

[0007] To achieve the above objectives, the present invention provides a dual-optical-system wind-avoidance zone scanning method, comprising the following steps:

[0008] Step 1: Distribute the dual optical systems sequentially along the wind field direction so that the working area is covered by the dual optical systems along the boundary line perpendicular to the wind field direction.

[0009] Step 2: Obtain the cross-sectional profile of the current layer in the sintering region by slicing; and obtain the center line of the sintering region along the wind direction, which is recorded as the partition line;

[0010] Step 3: Obtain the four regions divided by the boundary line and the partition line in the working area. Obtain the coordinates of all vertices in the cross-sectional contours of each region, as well as the coordinates of all intersection points where the cross-sectional contours intersect with the boundary line and the partition line. Substitute all the vertex coordinates and intersection point coordinates into the following formula to obtain the total contour area of ​​each region.

[0011]

[0012] Where the coordinates of the i-th point are (xi, yi), and n is the total number of all vertices and intersections in each region;

[0013] Step 4: Select any two regions at opposite angles. By moving the partition line in parallel, minimize the absolute value of the difference in the total area of ​​the two regions at opposite angles. At this point, the partition line is in the optimal position.

[0014] Step 5: Divide the four regions according to the partition line of the optimal position, and control the dual optical system to simultaneously perform parallel scans on the two regions of the selected opposite angles; after the scans of the two regions are completed, simultaneously perform parallel scans on the corresponding two regions of another set of opposite angles.

[0015] As a further preferred embodiment of the present invention, when the cross-sectional profile of the current layer is symmetrical about the dividing line, the following steps are included after step four and before step five:

[0016] Obtain the sum of the total area of ​​the outlines of two regions at a selected set of opposite angles, denoted as the first sum; and obtain the sum of the total area of ​​the outlines of two regions at another set of opposite angles, denoted as the second sum. By continuing to translate the partition line, the absolute value of the difference between the first sum and the second sum is minimized, and the position of the partition line is updated to the optimal position.

[0017] As a further preferred embodiment of the present invention, the parallel moving partition lines are used, and a recursive algorithm is employed to minimize the absolute value of the difference between the total area of ​​the two regions at the selected opposite angles, as well as to minimize the absolute value of the difference between the first sum and the second sum.

[0018] As a further preferred embodiment of the present invention, the partition lines are moved in parallel and at equal intervals in a manner of alternating up and down or down and up.

[0019] As a further preferred embodiment of the present invention, the parallel scanning in step five refers to using several parallel lines to fill and scan the filling area of ​​the cross-sectional contour.

[0020] As a further preferred embodiment of the present invention, the coordinates of all vertices in all cross-sectional contours in each region are obtained directly from the contour slice file.

[0021] As a further preferred embodiment of the present invention, the working area is divided equally by a dividing line.

[0022] The present invention also provides a dual-optical-system wind-avoidance zone scanning device, 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 dual-optical-system wind-avoidance zone scanning method described above.

[0023] The present invention also provides an additive manufacturing apparatus, including the aforementioned dual-optical-system wind-avoidance partition scanning device.

[0024] The dual-optical system wind-avoidance partition scanning method, apparatus, and additive manufacturing equipment of the present invention obtains the coordinates of all vertices in the cross-sectional contours of each region in the working area, as well as the coordinates of all intersection points where the cross-sectional contours intersect with the dividing lines and partition lines. Substituting all vertex and intersection coordinates into the following formula yields the total contour area of ​​each region. Then, two regions at an arbitrary angle are selected, and the partition lines are moved parallel to minimize the absolute value of the difference in the total contour areas of the two regions at the selected angle; at this point, the position of the partition lines is the optimal position. Finally, the four regions are re-divided according to the partition lines at the optimal position, and the dual-optical system is controlled to simultaneously perform parallel scanning on the two regions at the selected angles. After the scanning of these two regions is completed, parallel scanning is simultaneously performed on the corresponding two regions at another set of angles, reducing the wind-avoidance waiting time of the dual-optical scanning system and improving the sintering efficiency of the workpiece.

[0025] Moreover, the present invention employs a method of calculating the area of ​​the region covered by the contour slice data of the current layer. The calculation requires less data and the calculation process is fast and simple, avoiding the host computer software from spending a lot of time calculating the wind-avoidance scanning task allocation, thereby improving the efficiency of wind-avoidance scanning task allocation. Attached Figure Description

[0026] Figure 1 A flowchart of a method according to Embodiment 1 of the dual optical system wind-avoiding zone scanning method of the present invention;

[0027] Figure 2 A state of an embodiment of the dual-optical system wind-avoiding zone scanning method of the present invention. Figure 1 ;

[0028] Figure 3 for Figure 2 Local state diagram;

[0029] Figure 4 A state of an embodiment of the dual-optical system wind-avoiding zone scanning method of the present invention. Figure 2 ;

[0030] Figure 5 The flowchart is shown in Embodiment 2 of the dual-optical-system wind-avoidance zone scanning method of the present invention.

[0031] Marked in the image:

[0032] 1. Wind direction, 2. Working area, 3. Cross-sectional profile, 4. Zoning line, 5. Boundary line, 21. First zone, 22. Second zone, 23. Third zone, 24. Fourth zone. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] When scanning the filling area of ​​an additive manufacturing machine, parallel scan lines are typically used, scanning the filling area line by line according to a set line spacing. Therefore, there is a linear relationship between the filling area of ​​the workpiece in the current layer and the total length of the scanned filling lines. When the workpiece is scanned at a set speed, there is also a linear relationship between the filling area of ​​the workpiece in the current layer and the total time taken to scan the filling lines. Therefore, allocating wind-avoidance scanning tasks based on the total area covered by the contour can be equivalent to allocating wind-avoidance scanning tasks based on the time taken to scan the filling lines.

[0035] Example 1

[0036] Based on the above innovative ideas, the inventors of this application have specifically proposed a dual-optical-system wind-avoidance zone scanning method, such as... Figure 1 As shown, the scanning method includes the following steps:

[0037] Step 11: Distribute the dual optical systems sequentially along the wind field direction 1 so that the working area 2 is covered by the dual optical systems along the boundary line 5 perpendicular to the wind field direction 1.

[0038] Step 12: Obtain the cross-sectional profile 3 of the current layer in the sintering region by slicing; and obtain the center line of the sintering region along the wind direction 1, which is recorded as the partition line 4;

[0039] Step 13: Obtain the four regions in working area 2 that are divided by boundary line 5 and partition line 4, such as... Figure 2 As shown, it includes a first region 21, a second region 22, a third region 23 and a fourth region 24, with the first region 21 and the third region 23 being diagonal regions, and the second region 22 and the fourth region 24 being diagonal regions.

[0040] Obtain the coordinates of all vertices in all cross-sectional contours 3 within each region, as well as the coordinates of all intersection points where cross-sectional contour 3 intersects with boundary line 5 and partition line 4, such as... Figure 3 As shown, 41a, 41b, 41c, 41d, 41e, 41f, 41g, 41h, 41i, 41j, and 41k are all the vertices of the cross-sectional contour 3, and their coordinate values ​​can be obtained directly from the contour slice file; while 42a and 42b are the intersection points of the partition line 4 and the cross-sectional contour 3.

[0041] Substitute all vertex coordinates and intersection coordinates into the following formula to obtain the total contour area of ​​each region;

[0042]

[0043] Where the coordinates of the i-th point are (xi, yi), and n is the total number of all vertices and intersections in each region;

[0044] Step 14: Arbitrarily select two regions at opposite angles (for example, you can first select the first region 21 and the third region 23). By moving the partition line 4 in parallel, make the absolute value of the difference in the total area of ​​the two regions at opposite angles minimized. At this time, the position of the partition line 4 is the optimal position.

[0045] In this step, the partition line 4 is moved parallel to the target area, and a recursive algorithm is used to minimize the absolute value of the difference in the total area of ​​the two selected opposite corners. The specific steps are as follows:

[0046] Figure 2 When the initial position of the partition line 4 (the center line of working area 2) is reached, record the absolute value of the difference in the total area of ​​the outlines of the two selected opposite corners, and denot it as the reference value. With each parallel movement of the partition line 4, record the absolute value of the difference in the total area of ​​the outlines of the two selected opposite corners, and compare this absolute value with the reference value. If it is less than the reference value, replace the reference value and save it, and continue to move the partition line 4 in parallel; if it is greater than the reference value, continue to move the partition line 4 in parallel; until a minimum reference value is obtained, the position of the partition line 4 is the optimal position.

[0047] In practice, this step can also be implemented using other existing algorithms, which will not be listed here.

[0048] Preferably, in order to reduce computational steps and save data processing time, the partition line 4 is moved parallel and equidistantly in an up-and-down or down-and-up manner to minimize the absolute value of the difference in the total area of ​​the two regions at the selected opposite angles. Of course, in specific implementations, it can also be moved continuously upwards, continuously downwards, or randomly, and this application does not limit it.

[0049] Step 15: Divide the four regions according to the partition line 4 of the optimal position, and control the dual optical system to simultaneously perform parallel scanning on the two regions of the selected opposite angles; after the scanning of the two regions (first region 21 and third region 23) is completed, simultaneously perform parallel scanning on the corresponding two regions of another set of opposite angles (second region 22 and fourth region 24).

[0050] The parallel scanning in this step refers to filling the filling area of ​​the cross-sectional contour 3 using several parallel lines. Preferably, the working area 2 is evenly divided by the dividing line 5, such as... Figure 2 and Figure 4 As shown.

[0051] Example 2

[0052] The dual-optical system wind-avoiding zone scanning method of this embodiment, such as Figure 5 As shown, it includes the following steps:

[0053] Step 21: Distribute the dual optical systems sequentially along the wind field direction 1 so that the working area 2 is covered by the dual optical systems along the boundary line 5 perpendicular to the wind field direction 1.

[0054] Step 22: Obtain the cross-sectional profile 3 of the current layer in the sintering region by slicing; and obtain the center line of the sintering region along the wind direction 1, which is recorded as the partition line 4;

[0055] Step 23: Obtain the four regions in the working area 2 that are divided by the dividing line 5 and the partition line 4. Obtain the coordinates of all vertices in the cross-sectional contour 3 in each region, as well as the coordinates of all intersection points where the cross-sectional contour 3 intersects with the dividing line 5 and the partition line 4. Substitute all the vertex coordinates and intersection point coordinates into the following formula to obtain the total contour area of ​​each region.

[0056]

[0057] Where the coordinates of the i-th point are (xi, yi), and n is the total number of all vertices and intersections in each region;

[0058] Step 24: Select any two regions at opposite angles. By moving the partition line 4 in parallel, minimize the absolute value of the difference in the total area of ​​the two regions at opposite angles. At this point, the position of the partition line 4 is the optimal position.

[0059] Step 25: Obtain the sum of the total areas of the outlines of two regions at opposite angles in a selected set, denoted as the first sum; and obtain the sum of the total areas of the outlines of two regions at opposite angles in another set, denoted as the second sum. Continue to translate the partition line 4 to minimize the absolute value of the difference between the first sum and the second sum. At this point, the position of partition line 4 is updated to the optimal position. Minimizing the absolute value of the difference between the first sum and the second sum can also be achieved using a recursive algorithm, which will not be detailed here.

[0060] Step 26: Divide the four regions according to the partition line 4 at the optimal position, and control the dual optical system to simultaneously perform parallel scanning on the two regions at the selected opposite angles; after the scanning of the two regions is completed, simultaneously perform parallel scanning on the corresponding two regions at another set of opposite angles.

[0061] This embodiment addresses the special case where the cross-sectional profile of the current layer in the working area is symmetrical about the boundary line. When this condition is met, the technical solution of Embodiment 2 will minimize the scanning waiting time of the entire working area, thereby further improving work efficiency.

[0062] It should be noted here that, although Figures 2-4 The cross-sectional profile 3 of the current layer in the working area 2 shown in the image includes two workpieces. However, in specific implementations, this application is not limited to the number of workpieces included in the cross-sectional profile 3; for example, it can be one or more, all of which are applicable to the above-mentioned technical solutions of this application. Of course, although Figures 2-4 The cross-sectional profile 3 in the figure does not have any intersection points, but in the specific implementation, it may have intersection points with the dividing line 5. In this case, the total area of ​​the profile in each region includes the coordinates of all intersection points where the cross-sectional profile 3 intersects with the dividing line 5.

[0063] The present invention also provides a dual-optical-system wind-avoidance zone scanning device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the dual-optical-system wind-avoidance zone scanning method described in any of the above embodiments.

[0064] The present invention also provides an additive manufacturing apparatus, including the dual optical system wind-avoiding zone scanning device described in any of the above embodiments.

[0065] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those skilled in the art, several modifications and improvements can be made 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 dual-optical-system wind-avoidance zone scanning method, characterized in that, Includes the following steps: Step 1: Distribute the dual optical systems sequentially along the wind field direction so that the working area is covered by the dual optical systems along the boundary line perpendicular to the wind field direction. Step 2: Obtain the cross-sectional profile of the current layer in the sintering region by slicing; and obtain the center line of the sintering region along the wind direction, which is recorded as the partition line; Step 3: Obtain the four regions divided by the boundary line and the partition line in the working area. Obtain the coordinates of all vertices in the cross-sectional contours of each region, as well as the coordinates of all intersection points where the cross-sectional contours intersect with the boundary line and the partition line. Substitute all the vertex coordinates and intersection point coordinates into the following formula to obtain the total contour area of ​​each region. ； Where the coordinates of the i-th point are (xi, yi), and n is the total number of all vertices and intersections in each region; Step 4: Select any two regions at opposite angles. By moving the partition line in parallel, minimize the absolute value of the difference in the total area of ​​the two regions at opposite angles. At this point, the partition line is in the optimal position. Step 5: The four regions are redefined according to the optimal zoning lines. The dual optical system is then used to simultaneously perform parallel scans on two regions at the selected opposite angles. After scanning these two regions, parallel scans are then performed on the corresponding two regions at another set of opposite angles. When the cross-sectional profile of the current layer is symmetrical about the dividing line, the following steps are included after step four and before step five: Obtain the sum of the total area of ​​the outlines of two regions at a selected set of opposite angles, denoted as the first sum; and obtain the sum of the total area of ​​the outlines of two regions at another set of opposite angles, denoted as the second sum. By continuing to translate the partition line, the absolute value of the difference between the first sum and the second sum is minimized, and the position of the partition line is updated to the optimal position.

2. The dual-optical-system wind-avoidance zone scanning method according to claim 1, characterized in that, The parallel movement of the partition lines is used, and a recursive algorithm is employed to minimize the absolute value of the difference between the total areas of the two regions at the selected opposite angles, as well as to minimize the absolute value of the difference between the first sum and the second sum.

3. The dual-optical-system wind-avoidance zone scanning method according to claim 2, characterized in that, The partition lines are moved parallel and equidistantly in a pattern of alternating up and down or down and up.

4. The dual-optical-system wind-avoidance zone scanning method according to claim 1, characterized in that, The parallel scanning in step five refers to using several parallel lines to fill and scan the area of ​​the cross-sectional contour.

5. The dual-optical-system wind-avoidance zone scanning method according to claim 1, characterized in that, The coordinates of all vertices in the contours of all sections in each region are obtained directly from the contour slice file.

6. The dual-optical-system wind-avoidance zone scanning method according to any one of claims 1 to 5, characterized in that, The work area is divided equally by the dividing line.

7. A dual-optical-system wind-avoidance zone scanning device, characterized in that, The system includes a memory and a processor, the memory storing a computer program, characterized in that the processor executes the computer program to implement the steps of the dual optical system wind-avoiding zone scanning method according to any one of claims 1 to 6.

8. An additive manufacturing apparatus, characterized in that, Includes the dual-optical-system wind-avoidance partition scanning device as described in claim 7.

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