A method for processing workpieces using laser selective melting equipment

Abstract

The present invention discloses a method for processing a workpiece using a selective laser melting device, including: placing workpieces to be processed distributed in an array on the bearing area of the bearing substrate; during the process of laser scanning the workpieces to be processed, purging the workpieces to be processed with a gas; the air flow direction of the gas is parallel to the bearing substrate, the included angle between the direction of the laser scanning path and the air flow direction of the gas is a first included angle, and the direction of the laser scanning path is adjustable. An included angle can be formed between the direction of the laser scanning path and the air flow direction of the gas, the direction of the laser scanning path can be adjusted, and during the process of laser scanning the workpieces to be processed, gas can be blown to the workpieces to be processed. By means of the gas, by-products such as spatter and metal vapor generated instantaneously when a tiny molten pool is formed can be carried away, so as to blow the by-products away from the workpieces to be processed, prevent the by-products from falling on the workpieces to be processed, reduce the influence of the by-products on the quality of the workpieces to be processed, and improve the processing quality.

Description

Technical Field

[0001] This invention belongs to the field of laser selective melting technology, specifically relating to a method for processing workpieces using laser selective melting equipment. Background Technology

[0002] Selective laser melting (SLM) is a major technique in metal additive manufacturing. This technology utilizes a high-power-density laser beam to scan a bed of metal powder layer by layer, following a path planned in a 3D CAD slicing model. The scanned metal powder undergoes a melting and solidification process, ultimately yielding a metal part with specific dimensional accuracy and surface roughness. During laser scanning for additive manufacturing, the high power density and concentrated energy of the laser cause the formation of tiny molten pools at the focal point. These tiny pools generate byproducts such as spatter and metal vapor, which degrade the quality of the processed workpiece. Summary of the Invention

[0003] The purpose of this invention is to provide a method for processing workpieces using a laser selective melting device, in order to solve the problem that byproducts generated during the additive manufacturing process of laser-scanned workpieces reduce the quality of the workpieces.

[0004] This invention provides a method for processing a workpiece using a laser selective melting device, the laser selective melting device including a support substrate for holding the workpiece to be processed, and the method including:

[0005] Workpieces to be processed are placed in an array on the bearing area of ​​the bearing substrate;

[0006] During the laser scanning process, the workpiece is purged with gas.

[0007] The gas flow direction is parallel to the substrate, and the angle between the laser scanning path direction and the gas flow direction is the first angle. The direction of the laser scanning path is adjustable.

[0008] Optionally, the first included angle is greater than or equal to 0 degrees and less than 180 degrees; and / or

[0009] Before purging the workpiece with gas, the process also includes: equalizing the gas flow; and / or

[0010] The gas is an inert gas.

[0011] Optionally, during the laser scanning process of the additive layers of the workpiece, the laser scanning paths of adjacent additive layers are different.

[0012] Optionally, the angle between the laser scanning paths of adjacent additive layers is 1-8°.

[0013] Optionally, during the laser scanning of the additive layers of the workpiece, the angle between the direction of the laser scanning path of adjacent additive layers and the direction of gas flow is the same.

[0014] Optionally, during the laser scanning of the additive layer of the workpiece, the angle between the direction of the laser scanning path and the direction of gas flow is 30-60°.

[0015] Optionally, the angle between the gas flow direction and the length direction of the column containing the workpiece is an acute or obtuse angle.

[0016] Optionally, during the laser scanning of the additive layer of the workpiece, the path from the workpiece in row n, column m to the workpiece in row (n-2), column m+1 is the first path, and the path from the workpiece in row n, column m to the workpiece in row n, column m+1 is the second path. The angle between the first path and the length direction of column m is the first angle, and the angle between the second path and the length direction of column m is the second angle. The angle between the gas flow direction and the length direction of the column is greater than or equal to the first angle and less than the second angle.

[0017] Optionally, the carrier substrate has multiple distribution zones, at least two of the distribution zones have different distribution densities of the workpieces to be processed, and the gas flow directions in the distribution zones with different distribution densities of the workpieces to be processed are different.

[0018] Optionally, the method further includes:

[0019] Collect the gas after purging the workpiece, filter the collected gas, and reuse it to purge the workpiece.

[0020] This invention discloses a method for processing workpieces using a laser selective melting device. The method includes: placing workpieces arranged in an array on a support area of ​​a support substrate; during laser scanning of the workpieces, blowing gas onto them; the gas flow direction is parallel to the support substrate, and the angle between the direction of the laser scanning path and the gas flow direction is a first angle, the direction of the laser scanning path being adjustable. The angle between the laser scanning path and the gas flow direction, and the adjustable laser scanning path, allows gas to be blown onto the workpiece during laser scanning. The gas carries away byproducts such as spatter and metal vapor generated during the formation of the micro-molten pool, preventing them from falling onto the workpiece, reducing their impact on the workpiece quality, and improving processing quality. Attached Figure Description

[0021] Figure 1 This is a schematic diagram showing the direction of airflow parallel to the length of the column of workpieces to be processed.

[0022] Figure 2 This is a schematic diagram of the airflow direction in this invention when it is not parallel to the length direction of the column of the workpiece.

[0023] Figure 3 This is a schematic diagram of the first path and the second path;

[0024] Figure 4 This is a schematic diagram of a laser scanning path;

[0025] Figure 5 This is another schematic diagram of the laser scanning path;

[0026] Figure 6 This is a schematic diagram of the laser scanning path and the airflow direction.

[0027] Attached Figure

[0028] Supporting substrate 10. Implementation

[0029] 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, not all, of the embodiments of the present invention. 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.

[0030] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0031] The following is in conjunction with the appendix Figures 1 to 6 The method for processing workpieces using a laser selective melting device according to an embodiment of the present invention will be described.

[0032] The present invention provides a method for processing a workpiece using a laser selective melting device, wherein the laser selective melting device includes a support substrate for holding the workpiece to be processed, and the method includes:

[0033] Workpieces to be processed are placed in an array on the bearing area of ​​the bearing substrate;

[0034] During the laser scanning process, the workpiece is purged with gas.

[0035] The gas flow direction is parallel to the substrate. The angle between the laser scanning path direction and the gas flow direction is the first angle. The laser scanning path direction is adjustable and can be parallel to the substrate. During laser scanning of the workpiece, the laser scanning path direction can be adjusted, and the gas flow direction can change accordingly. The first angle can remain fixed.

[0036] According to the method for processing workpieces using laser selective melting equipment according to embodiments of the present invention, an angle can be formed between the direction of the laser scanning path and the direction of gas flow. The direction of the laser scanning path can be adjusted. During the laser scanning of the workpiece, gas can be blown onto the workpiece. The gas can carry away byproducts such as spatter and metal vapor generated at the moment of forming a small molten pool, thereby blowing the byproducts away from the workpiece, preventing byproducts from falling onto the workpiece, reducing the impact of byproducts on the quality of the workpiece, and improving the processing quality.

[0037] In some embodiments, the first included angle may be greater than or equal to 0 degrees and less than 180 degrees; for example, the first included angle may be greater than or equal to 30 degrees and less than 120 degrees. During laser scanning of the workpiece, this allows the gas to carry away byproducts such as spatter and metal vapor generated during the formation of the micro-molten pool. The first included angle being greater than or equal to 0 degrees and less than 90 degrees helps to blow byproducts away from the laser-scanned area on the workpiece, preventing byproducts from falling into the scanned area and reducing their impact. In some embodiments, before purging the workpiece with gas, the process may further include:

[0038] Gas flow equalization. By equalizing the gas flow, the gas distribution can be made more uniform, improving the uniformity of gas distribution on different workpieces.

[0039] Optionally, the gas can be an inert gas. The inert gas may include at least one of nitrogen and argon. For example, the inert gas can be nitrogen or argon. Using an inert gas can protect the workpiece from oxidation.

[0040] Optionally, during the laser scanning process of the additive layers of the workpiece, the laser scanning paths of adjacent additive layers are different, which can improve the forming effect between layers and improve the forming quality.

[0041] In additive manufacturing, the laser scanning path of each layer is deflected at a certain angle from the laser scanning path of the previous layer. This avoids manufacturing defects caused by peak-valence overlap between passes due to laser scanning along the same path. For example, when scanning the current layer, the laser scanning path can be as follows: Figure 4 As shown, when scanning the next layer, a 5° offset from the previous layer will be used. The laser scanning path can be as follows: Figure 5 As shown, this will improve the forming effect between layers and improve the forming quality.

[0042] Optionally, the angle between the laser scanning paths of adjacent additive layers is 1-8°. For example, the angle between the laser scanning paths of adjacent additive layers is 5°. The specific angle can be selected according to the actual situation to improve the forming effect between layers and improve the forming quality.

[0043] According to some embodiments, during the laser scanning of the additive layers of the workpiece, the angle between the direction of the laser scanning path of adjacent additive layers and the direction of gas flow is the same.

[0044] During each layer forming process, the angle between the laser scanning path and the gas flow direction has an optimal angle. For example, when the angle between the laser scanning path a and the gas flow direction b is 45°, it can be as follows: Figure 6 As shown, its scanning forming has the optimal forming effect. Currently, in powder-layout additive manufacturing, in order to maintain the overall forming effect of the part, a scanning path with a rotating angle is used. For example, when scanning the Nth layer solid and contour, the angle between the laser scanning path and the gas flow direction is 45°. When scanning the N+1th layer, in order to avoid overlap of passes, the scanning path will rotate by a certain angle, such as 5°. At this time, the angle between the laser scanning path and the gas flow direction becomes 40°. However, the forming effect of this angle is not as good as that of 45°. Based on this, the gas flow direction can be changed to adjust the wind direction during the forming process, so that the wind direction always maintains the optimal angle with the scanning path, thereby ensuring the forming effect of each layer.

[0045] Optionally, during the laser scanning process of the additive layer on the workpiece, the angle between the direction of the laser scanning path and the direction of gas flow can be 30-60°. For example, the angle between the direction of the laser scanning path and the direction of gas flow can be 45°, and the specific angle can be selected according to the actual situation.

[0046] In some embodiments, the angle between the gas flow direction and the length direction of the column containing the workpiece is an acute or obtuse angle. For example, gas is blown from one edge of the supporting substrate towards the workpiece, the gas flow direction is parallel to the supporting substrate, and the angle between the gas flow direction and the length direction of the column containing the workpiece is an acute or obtuse angle. This angle can be greater than or equal to 60° and less than 90°. By blowing gas onto the workpiece, byproducts such as spatter and metal vapor generated during the formation of the micro-molten pool can be carried away, preventing them from falling onto the workpiece. The gas can be air or an inert gas, such as argon or nitrogen. Figure 1 As shown, the gas flow direction is parallel to the length of the column, and byproducts blown away by the next row tend to fall onto the workpiece to be processed in the previous row. For example... Figure 2 As shown, the angle between the gas flow direction and the length direction of the column containing the workpiece is an acute or obtuse angle. The gas flow is tilted, which makes it less likely for by-products blown away in the next row to fall onto the workpiece in the previous row.

[0047] In some embodiments, during the laser scanning of the additive layer of the workpiece, the path from the workpiece in row n, column m to the workpiece in row (n-2), column m+1 is the first path, and the path from the workpiece in row n, column m to the workpiece in row n, column m+1 is the second path. The angle between the first path and the length direction of column m is the first angle, and the angle between the second path and the length direction of column m is the second angle. The angle between the gas flow direction and the length direction of the column is greater than or equal to the first angle and less than the second angle. m and n can be positive integers; for example, n can be 8 and m can be 1. The gas flow direction can increase the distance between the two workpieces. By blowing gas onto the workpieces, byproducts are blown away from the workpieces, causing them to fall into the area between the two workpieces and preventing them from falling onto the workpieces.

[0048] like Figure 3As shown, n can be 8, m can be 1, the top row is row 1, the leftmost column is column 1, the path from the workpiece in row 8, column 1 to the workpiece in row 6, column 2 is the first path s1, and the path from the workpiece in row 8, column 1 to the workpiece in row 8, column 2 is the second path s2. The angle between the first path s1 and the length direction s of column 1 is the first angle, and the angle between the second path s2 and the length direction s of column 1 is the second angle. The angle between the gas flow direction and the length direction of the column is greater than or equal to the first angle and less than the second angle; that is, the gas flow direction can be in the s1 direction or in a direction between s1 and s2. The gas flow direction allows for a larger distance between the two workpieces. By blowing gas onto the workpieces, byproducts are blown away from them, causing them to fall into the area between the two workpieces and preventing them from falling onto the workpieces. During application, the workpieces to be processed can be arranged in an array on a 400mm*400mm carrier substrate. The spacing between adjacent workpieces in each row can be 5-12mm, such as 10mm. When laser printing is turned on, the inert protective gas can flow along... Figure 2 It blows out in the direction shown.

[0049] In some embodiments, the carrier substrate has multiple distribution zones, and the distribution density of the workpieces in at least two of the distribution zones is different. The gas flow direction is different in the distribution zones with different workpiece distribution densities. The spacing between adjacent workpieces with different distribution densities is different, and the required gas flow direction is also different.

[0050] Optionally, the method may also include:

[0051] Collect the gas after purging the workpiece, filter the collected gas, and reuse it to purge the workpiece.

[0052] The gas that is blown away from the workpiece carries byproducts. These byproducts can be removed by filtration. The filtered gas flow then re-enters the intake pipe, allowing the gas to be recycled.

[0053] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for processing a workpiece using a laser selective melting device, the laser selective melting device comprising a support substrate for holding the workpiece to be processed, characterized in that, The method includes: Workpieces to be processed are placed in an array on the bearing area of ​​the bearing substrate; During the laser scanning process, the workpiece is purged with gas. The gas flow direction is parallel to the substrate, and the direction of the laser scanning path is adjustable. In the process of laser scanning the additive layer of the workpiece, the laser scanning paths of adjacent additive layers are different. The angle between the direction of the laser scanning path and the direction of gas flow is 30-60°. The path from the workpiece in row n, column m to the workpiece in row (n-2), column m+1 is the first path, and the path from the workpiece in row n, column m to the workpiece in row n, column m+1 is the second path. The angle between the first path and the length direction of column m is the first angle, and the angle between the second path and the length direction of column m is the second angle. The angle between the direction of gas flow and the length direction of column m is greater than or equal to the first angle and less than the second angle.

2. The method according to claim 1, characterized in that, Before purging the workpiece with gas, the process also includes: equalizing the gas flow; and / or The gas is an inert gas.

3. The method according to claim 1, characterized in that, The angle between the laser scanning paths of adjacent additive layers is 1-8°.

4. The method according to claim 1, characterized in that, During the laser scanning process of the additive layers of the workpiece, the angle between the direction of the laser scanning path of adjacent additive layers and the direction of gas flow is the same.

5. The method according to claim 1, characterized in that, The angle between the gas flow direction and the length direction of the column containing the workpiece is an acute or obtuse angle.

6. The method according to claim 1, characterized in that, The substrate has multiple distribution zones, and the distribution density of the workpieces to be processed in at least two of the distribution zones is different. The gas flow direction is different in the distribution zones with different distribution densities of the workpieces to be processed.

7. The method according to claim 6, characterized in that, Also includes: Collect the gas after purging the workpiece, filter the collected gas, and reuse it to purge the workpiece.

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