A multi-laser scanning method, apparatus and additive manufacturing apparatus

Abstract

A kind of multi-laser scanning method, device and additive manufacturing equipment, wherein the multi-laser scanning method comprises: obtaining the cross-sectional profile of the current slice layer obtained by slicing in the workpiece to be printed;The cross-sectional profile is filled with parallel filling lines;All filling lines intersecting with the preset segmentation line in the cross-sectional profile are obtained, and the intersection points are marked as preset segmentation points;New segmentation points are dynamically determined according to the length of the two scanning lines separated by each filling line and the preset segmentation points in turn, and new segmentation lines are formed by connecting all new segmentation points.The multi-laser scanning method, device and additive manufacturing equipment of the present application can make the segmentation line at the multi-laser overlap not a simple straight line, but a curve, which avoids frequent start and stop of the laser, and avoids the disadvantage of excessive energy at the sintering site, thereby improving the overlap quality of the multi-laser.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of additive manufacturing, in particular to a multi-laser scanning method, device and additive manufacturing equipment. BACKGROUND

[0002] Additive manufacturing technology is a rapid manufacturing technology that forms a three-dimensional object by controlling a laser to scan layer by layer. The process flow is as follows: first, slice the three-dimensional model of the workpiece to obtain the contour information of each layer of the workpiece; uniformly spread the powder material on the surface of the work platform, and the laser selectively melts the powder according to the system instructions; after one section is completed, a new layer of material is spread, and selective scanning is continued according to the corresponding section information of the three-dimensional object; the next section is spread and scanned according to this method, and finally a three-dimensional object is obtained.

[0003] As the size of the workpiece to be printed becomes larger, using multiple lasers to sinter the working area can improve the sintering efficiency per unit area and shorten the sintering time per unit area.

[0004] The prior art multi-laser 3D printing equipment generally uses multiple lasers to scan when a scanning section crosses multiple laser regions. The current scanning task allocation is to divide the scanning lines that cross the dividing line by predefining a dividing line, that is, the scanning lines on one side of the dividing line (such as the scanning lines on the left side of the dividing line in FIG. 1) are scanned by the corresponding laser (such as laser 1 in FIG. 1), and the scanning lines on the other side of the dividing line (such as the scanning lines on the right side of the dividing line in FIG. 1) are scanned by the corresponding laser (such as laser 2 in FIG. 1). Figure 1 However, the dividing line does not consider the characteristics of the scanning lines in the dividing process, but divides and scans according to the pre-defined dividing line. However, since the scanning lines in the thin-walled region are short, it may cause the laser to be triggered multiple times in a very short distance, resulting in over-melting, and thus the forming quality of the thin-walled region and the contour edge is poor. Figure 1 SUMMARY Figure 1 Figure 1 In order to solve the above technical problems existing in the prior art, the present application provides a multi-laser scanning method, device and additive manufacturing equipment. The multi-laser scanning method dynamically adjusts the position of the filling line dividing point on the basis of the pre-defined dividing line according to the characteristics of the filling line to form a new dividing line, so that the multi-laser overlap is not simply a straight line dividing overlap, that is, the overlap quality of the multi-laser is improved.

[0005] In order to solve the above technical problems existing in the prior art, the present application provides a multi-laser scanning method, device and additive manufacturing equipment. The multi-laser scanning method dynamically adjusts the position of the filling line dividing point on the basis of the pre-defined dividing line according to the characteristics of the filling line to form a new dividing line, so that the multi-laser overlap is not simply a straight line dividing overlap, that is, the overlap quality of the multi-laser is improved.

[0006] ​​In order to achieve the above object, the present application provides a multi-laser scanning method, comprising at least two lasers, and a corresponding preset segmentation line is arranged in each slice layer in a splicing area between each two adjacent lasers, wherein the corresponding preset segmentation line of at least one slice layer in at least one splicing area is adjusted to obtain a new segmentation line by the following way:

[0007] Obtaining a cross-section contour of a current slice layer obtained by slicing in a workpiece to be printed;

[0008] Filling the cross-section contour by using parallel filling lines;

[0009] Obtaining all filling lines intersecting with the preset segmentation line in the cross-section contour, and the intersection points are recorded as preset segmentation points;

[0010] Dynamically determining new segmentation points according to the lengths of two scanning lines separated by the preset segmentation point for each filling line in sequence, and connecting all the new segmentation points to form a new segmentation line.

[0011] As a further preferred scheme of the present application, the dynamically determining new segmentation points according to the lengths of two scanning lines separated by the preset segmentation point for each filling line in sequence specifically comprises:

[0012] Obtaining the lengths of the two scanning lines separated by the preset segmentation point;

[0013] When the lengths of the two scanning lines are both less than a preset threshold, selecting a preset segmentation point of any filling line adjacent to the filling line as a reference point, and obtaining a perpendicular point by drawing a perpendicular line from the reference point to the filling line, and recording an end point of the filling line closest to the perpendicular point as a new segmentation point;

[0014] When the lengths of the two scanning lines are both less than a preset threshold, selecting a preset segmentation point of any filling line adjacent to the filling line as a reference point, and obtaining a perpendicular point by drawing a perpendicular line from the reference point to the filling line, and recording an end point of the filling line closest to the perpendicular point as a new segmentation point;

[0015] As a further preferred scheme of the present application, when the lengths of the two scanning lines are both less than a preset threshold, the selected filling line adjacent to the filling line is scanned earlier than the filling line.

[0016] As a further preferred scheme of the present application, the multi-laser scanning method further comprises:

[0017] When the lengths of the two scanning lines are both greater than a preset threshold, the preset segmentation point of the filling line is a new segmentation point.

[0018] As a further preferred scheme of the present application, the multi-laser scanning method further comprises:

[0019] When the filling line does not have a preset segmentation point, the filling line is not processed.

[0020] As a further preferred scheme of the present application, the preset threshold is 2 times of the spot diameter.

[0021] As a further preferred scheme of the present application, the multi-laser scanning method further comprises:

[0022] connecting all the new segmentation points to form a new segmentation line;

[0023] all the lasers scan the filling part of the cross-sectional profile under the allocation of the new segmentation line, and all the lasers scan the outline part of the cross-sectional profile under the allocation of the preset segmentation line.

[0024] The present application also provides a multi-laser scanning method, wherein the preset segmentation line corresponding to all the slice layers of all the splicing areas adopts the multi-laser scanning method according to any one of the above.

[0025] The present application also provides a multi-laser scanning device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor realizes the steps of the multi-laser scanning method according to any one of the above when executing the computer program.

[0026] The present application also provides an additive manufacturing equipment comprising the multi-laser scanning device according to the above.

[0027] The multi-laser scanning method, device and additive manufacturing equipment according to the present application can dynamically determine the new segmentation point (which can be the preset segmentation point or the preset segmentation point after moving) of each filling line according to the length of the two scanning lines separated by the preset segmentation point on the basis of the preset segmentation line, so as to form a new segmentation line, so that the segmentation line at the multi-laser splicing position is not a simple straight line but a curve, thereby avoiding frequent start and stop of the lasers and avoiding the disadvantage of excessive energy at the sintering position, and improving the splicing quality of the multi-laser. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 State of an embodiment of the multi-laser scanning method according to the present application Figure 1

[0029] Figure 2 State of an embodiment of the multi-laser scanning method according to the present application Figure 2

[0030] Figure 3 State of an embodiment of the multi-laser scanning method according to the present application Figure 3

[0031] Figure 4 ​​​State of an embodiment of the multi-laser scanning method provided by the present application Figure 4 . DETAILED DESCRIPTION

[0032] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0033] In order to avoid the prior art using a preset straight dividing line without considering the characteristics of the filling lines, resulting in poor forming quality of the thin-walled area and the contour edge. Moreover, according to the preset dividing line for division, it is also possible to trigger the start-stop state of the multiple lasers multiple times in a very short distance due to the short scanning, thereby causing the technical problem of over-melting. The present application provides a multi-laser scanning method, including at least two lasers, and each two adjacent lasers have a corresponding preset dividing line in each slice layer in a splicing area, wherein the corresponding preset dividing line of at least one slice layer of at least one splicing area is adjusted to obtain a new dividing line by the following way:

[0034] Obtaining a cross-sectional contour of a current slice layer obtained by slicing in a workpiece to be printed;

[0035] Filling the cross-sectional contour with parallel filling lines;

[0036] Obtaining all filling lines intersecting with the preset dividing line in the cross-sectional contour, and the intersection points are marked as preset dividing points (as shown in Figure 1 );

[0037] Dynamically determining a new dividing point according to the length of the two scanning lines separated by the preset dividing point of each filling line in turn, and connecting all the new dividing points to form a new dividing line.

[0038] Specifically, dynamically determining a new dividing point according to the length of the two scanning lines separated by the preset dividing point of each filling line in turn specifically includes:

[0039] Obtaining the length of the two scanning lines separated by the preset dividing point;

[0040] When the length of the two scanning lines (such as the two scanning lines obtained by separating the filling line 1 in Figure 2 by the preset dividing point) is less than a preset threshold, selecting the preset dividing point of any filling line (such as the filling line 2 in Figure 2 ) adjacent to the filling line as a reference point, and obtaining a perpendicular point (also called a projection point) from the reference point to the filling line, and marking the end point of the filling line closest to the perpendicular point as a new dividing point (such as the new dividing point in Figure 4(As shown); Specifically, the distances L1 and L2 between the two endpoints of scan line 1 and the projection point can be calculated respectively. Since L1 is less than L2, fill line 1 is scanned by laser 2. Because fill line 1 itself has a relatively short scan line segment, when it is divided according to the preset dividing line, the scan lines allocated to the two lasers are relatively short. Therefore, this method can allocate the fill line to one laser, thereby avoiding the appearance of short lines.

[0041] When one scan line has a length less than a preset threshold and the other scan line has a length greater than a preset threshold (e.g., ...), Figure 3 As shown), move the preset dividing point of the fill line to the middle of the fill line and record it as the new dividing point (e.g., Figure 3 As shown, Figure 3 The preset dividing points are only shown in location (to avoid them coinciding with the actual dividing points and becoming unclear). For a more detailed display, please refer to [link to documentation / reference]. Figure 3 , Figure 3 The actual dividing point is the new dividing point of fill line 2; this avoids the fill line being too short, which would cause frequent laser start-up and shutdown, and also result in excessively high energy at the overlap of adjacent lasers, leading to over-fusion. In a preferred embodiment of this application, the preset threshold is twice the spot diameter. Of course, in specific implementations, it can also be other parameters, which will not be listed here. Figure 3 As shown, the filler line 2 is shorter, and the length allocated to laser 2 according to the preset dividing line is longer than that of laser 1. Therefore, the preset dividing point is shifted to the right so that the lengths allocated to the two lasers are close. This can avoid frequent start-stop of the lasers and avoid excessive energy at the overlap, thus ensuring the sintering quality.

[0042] To further avoid warping and improve sintering quality, preferably, when the lengths of both scan lines are less than a preset threshold, the selected fill line adjacent to the fill line is scanned before the fill line. For example, if the scanning order of fill lines S1, S2, and S3 in the cross-sectional profile is fill line S1, fill line S2, and fill line S3 respectively, then when determining the dividing point of fill line S2, it can be determined by fill line S1. That is, a perpendicular line is drawn from the preset dividing point of fill line S1 to the fill line to obtain the perpendicular point (also called the projection point), and the endpoint of the fill line closest to the perpendicular point is recorded as the new dividing point.

[0043] As one embodiment of this example, the multi-laser scanning method further includes:

[0044] When the lengths of both scan lines are greater than the preset threshold, the preset dividing point of the fill line becomes the new dividing point.

[0045] as well as

[0046] When the filling line does not have a preset split point, the filling line is not processed. That is, the two cases do not need to be processed in the present application.

[0047] As a preferred mode of the present application, the multi-laser scanning method further comprises:

[0048] Connecting all new split points to form a new split line;

[0049] All lasers scan the filling part of the cross-sectional profile under the allocation of the new split line; and all lasers scan the contour part of the cross-sectional profile under the allocation of the preset split line. In this way, the filling part and the contour part can still be scanned by the same laser under the premise of avoiding frequent start and stop of the laser and avoiding excessive energy at the sintering position, thereby avoiding the influence of voids caused by scanning of the filling part and the contour part by two lasers on the sintering quality, i.e., further ensuring the sintering quality. It should be noted that the laser scans the filling part of the cross-sectional profile under the allocation of the new split line; and the laser scans the contour part of the cross-sectional profile under the allocation of the preset split line, and the allocation principle is in accordance with the nearest principle, i.e., as shown in the drawing, laser 1 scans the contour line (based on the preset split line) and the filling line (based on the new split line) located near it; laser 2 scans the contour line (based on the preset split line) and the filling line (based on the new split line) located near it. Figures 1-4

[0050] The present application has the advantages that: Figures 1-4 Only the preset split line corresponding to one slice layer of one splicing area is taken as an example to describe that the new split line is obtained by adjusting the scheme of the above-mentioned embodiments, and then scanning is performed according to the new split line. It should be noted that the above-mentioned embodiments can be performed with reference to the above-mentioned embodiments for other slice layers or other splicing areas, and repeated description is not given here. In specific implementation, part of the splicing areas or all of the splicing areas of a plurality of slice layers can be selected according to design needs; or part or all of the splicing areas of all slice layers can be selected to perform the scheme of the above-mentioned embodiments; and the present application is not limited in this regard.

[0051] The present application also provides a multi-laser scanning method, and the preset split line corresponding to all slice layers of all splicing areas adopts the multi-laser scanning method of any one of the above-mentioned embodiments. In this way, the sintering quality of the workpiece to be printed can be better ensured.

[0052] The present application also provides a multi-laser scanning device, which comprises a memory and a processor, and the memory stores a computer program. When the processor executes the computer program, the steps of the multi-laser scanning method of any one of the above-mentioned embodiments are implemented.

[0053] ​The application further provides an additive manufacturing device comprising the multi-laser scanner device.

[0054] The technical features of the above embodiments can be combined in any manner. To make the description simple, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not contradict, they shall be considered as the scope of the description. The above embodiments only express several implementation manners of the application, the description is specific and detailed, however, it shall not be understood as a limitation on the patent scope of the application. It should be pointed out that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the application, and these all belong to the protection scope of the application. Therefore, the patent protection scope of the application shall be subject to the appended claims.

Claims

1. A multi-laser scanning method, comprising at least two lasers, a corresponding preset division line being provided in each slice layer between each two adjacent lasers, characterized in that, The preset segmentation line corresponding to at least one slice layer of at least one splicing area is adjusted to obtain a new segmentation line by the following method: obtaining a cross-section contour of a current slice layer obtained by slicing in the workpiece to be printed; filling the cross-section contour with parallel filling lines; obtaining all filling lines intersecting the preset segmentation line in the cross-section contour, and recording the intersection points as preset segmentation points; dynamically determining new segmentation points according to the lengths of two scanning lines of each filling line separated by the preset segmentation points in sequence, and connecting all the new segmentation points to form a new segmentation line; wherein The multi-laser scanning method further comprises: when the filling line does not have a preset segmentation point, the filling line is not processed.

2. The multi-laser scanning method of claim 1, wherein, dynamically determining new segmentation points according to the lengths of two scanning lines of each filling line separated by the preset segmentation points in sequence comprises: obtaining the lengths of two scanning lines separated by the preset segmentation points; when the lengths of the two scanning lines are both less than a preset threshold, selecting a preset segmentation point of any filling line adjacent to the filling line as a reference point, and obtaining a perpendicular point from the reference point to the filling line, and recording the nearest endpoint of the filling line to the perpendicular point as a new segmentation point; when the lengths of the two scanning lines are both less than a preset threshold, selecting a preset segmentation point of any filling line adjacent to the filling line as a reference point, and obtaining a perpendicular point from the reference point to the filling line, and recording the nearest endpoint of the filling line to the perpendicular point as a new segmentation point.

3. The multi-laser scanning method of claim 2, wherein, When the lengths of the two scanning lines are both less than a preset threshold, the selected filling line adjacent to the filling line is scanned before the filling line.

4. The multi-laser scanning method of claim 3, wherein, The multi-laser scanning method further comprises: when the lengths of the two scanning lines are both greater than a preset threshold, the preset segmentation point of the filling line is a new segmentation point.

5. The multi-laser scanning method of claim 4, wherein, The preset threshold is 2 times the diameter of the spot.

6. The multi-laser scanning method according to any one of claims 1 to 5, characterized in that, The multi-laser scanning method further comprises: connecting all the new segmentation points to form a new segmentation line; all the lasers scan the filling lines in the cross-section contour under the allocation of the new segmentation line, and all the lasers scan the contour part of the cross-section contour under the allocation of the preset segmentation line.

7. A multi-laser scanning device, characterized by The computer program product comprises a memory and a processor, and the memory stores the computer program, characterized in that the processor executes the computer program to realize the steps of the multi-laser scanning method in any one of claims 1 to 6.

8. An additive manufacturing apparatus, characterized by The multi-laser scanning device of claim 7.

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