Method for processing workpieces by using selective laser melting apparatus

Abstract

A method for processing workpieces by using a selective laser melting apparatus. The method comprises: placing workpieces to be processed, which are distributed in an array, on a bearing area of a bearing substrate (10); and using a gas to purge the workpieces to be processed during the process of using a laser to scan said workpieces. A gas flow direction of the gas is parallel to the bearing substrate; an included angle between the direction of a laser scanning path and the gas flow direction of the gas is a first included angle; and the direction of the laser scanning path can be adjusted. The included angle can be formed between the direction of the laser scanning path and the gas flow direction of the gas, the direction of the laser scanning path can be adjusted, the gas can be blown onto the workpieces to be processed during the process of using the laser to scan said workpieces, and by-products such as splashes and metal steam generated at the moment when a tiny molten pool is formed can be carried away by means of the gas, such that the by-products are blown away from said workpieces, the by-products are prevented from falling onto said workpieces, and the influence of the by-products on the quality of said workpieces is reduced, thus improving the processing quality.

Description

Method for processing workpiece using laser selective melting equipment Related applications

[0001] This application claims priority to patent application 202311619101.2 filed with the China Patent Office on November 30, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The invention belongs to the technical field of laser selective melting, and in particular relates to a method for processing a workpiece by using laser selective melting equipment. Background Art

[0003] Selective laser melting (SLM) is a major technology in metal additive manufacturing. It uses a high-power-density laser beam to scan a bed of metal powder layer by layer, following a path mapped in a 3D CAD slice model. The scanned metal powder undergoes a process of melting and solidification, ultimately yielding metal parts with a certain degree of dimensional accuracy and surface roughness. During the additive manufacturing process, laser scanning of workpieces creates a tiny molten pool at the focal point due to the high power density and concentrated energy of the laser. This pool is then accompanied by byproducts such as spatter and metal vapor, which can reduce the quality of the workpiece. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a method for processing a workpiece using a selective laser melting device, so as to solve the problem that the by-products generated during the process of laser scanning the workpiece for material addition will reduce the quality of the workpiece.

[0005] An embodiment of the present invention provides a method for processing a workpiece using a selective laser melting device, wherein the selective laser melting device includes a carrier substrate for supporting the workpiece to be processed. The method includes: placing the workpiece to be processed distributed in an array on a carrier area of ​​the carrier substrate; using gas to purge the workpiece to be processed during laser scanning of the workpiece to be processed; the gas flow direction of the gas is parallel to the carrier substrate, the angle between the direction of the laser scanning path and the gas flow direction is a first angle, and the direction of the laser scanning path is adjustable.

[0006] Optionally, the first angle is greater than or equal to 0 degrees and less than 180 degrees; and / or before using the gas to purge the workpiece, it also includes: uniformly flowing the gas; and / or the gas is an inert gas.

[0007] Optionally, during the laser scanning process of the additive layers of the workpiece to be processed, the laser scanning paths of adjacent additive layers are different.

[0008] Optionally, the angle between the laser scanning paths of adjacent additive layers is 1-8°.

[0009] Optionally, during the laser scanning process of the additive layers of the workpiece to be processed, the angles between the directions of the laser scanning paths of adjacent additive layers and the gas flow direction are the same.

[0010] Optionally, during the laser scanning process of the additive layer of the workpiece to be processed, the angle between the direction of the laser scanning path and the gas flow direction is 30-60°.

[0011] Optionally, the angle between the gas flow direction and the length direction of the column where the workpieces to be processed are located is an acute angle or an obtuse angle.

[0012] Optionally, during the laser scanning process of the additive layer of the workpiece to be processed, the path from the workpiece to be processed in the nth row and mth column to the workpiece to be processed in the n-2th row and m+1th column is a first path, and the path from the workpiece to be processed in the nth row and mth column to the workpiece to be processed in the nth row and m+1th column is a second path, the angle between the first path and the length direction of the mth column is a first angle, the angle between the second path and the length direction of the mth column is a second angle, and 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.

[0013] Optionally, the carrier substrate has a plurality of distribution areas, distribution densities of the workpieces to be processed in at least two of the distribution areas are different, and the gas flow directions of the gas in the distribution areas with different distribution densities of the workpieces to be processed are different.

[0014] Optionally, the method further comprises: collecting the gas after purging the workpiece to be processed, filtering the collected gas and reusing it to purge the workpiece to be processed.

[0015] The embodiment of the present invention provides a method for processing a workpiece using a laser selective melting device, the method comprising: placing workpieces to be processed distributed in an array on the supporting area of ​​the supporting substrate; using gas to purge the workpieces to be processed during laser scanning of the workpieces to be processed; the gas flow direction of the gas is parallel to the supporting substrate, the angle between the direction of the laser scanning path and the gas flow direction is a first angle, and the direction of the laser scanning path is adjustable. An angle can be formed between the direction of the laser scanning path and the gas flow direction, the direction of the laser scanning path is adjustable, and during laser scanning of the workpieces to be processed, gas can be blown toward the workpieces to be processed, and the gas can carry away byproducts such as spatter and metal vapor generated at the moment of formation of the micro-molten pool, so as to blow the byproducts away from the workpieces to be processed, prevent the byproducts from falling on the workpieces to be processed, reduce the impact of the byproducts on the quality of the workpieces to be processed, and improve the processing quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG1 is a schematic diagram showing the case where the airflow direction is parallel to the length direction of a row of workpieces to be processed;

[0017] FIG2 is a schematic diagram showing a case where the airflow direction is not parallel to the length direction of a row of workpieces to be processed according to the present invention;

[0018] FIG3 is a schematic diagram of the first path and the second path;

[0019] FIG4 is a schematic diagram of a laser scanning path;

[0020] FIG5 is another schematic diagram of the laser scanning path;

[0021] FIG6 is a schematic diagram of the laser scanning path and the airflow direction.

[0022] Attached photos

[0023] The carrier substrate 10 . DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] The terms "first," "second," and the like in the specification and claims of the present invention are used to distinguish similar objects and are not intended to describe a particular order or precedence. It should be understood that such terms are interchangeable where appropriate, so that embodiments of the present invention can be implemented in sequences other than those illustrated or described herein. Furthermore, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the connected objects are in an "or" relationship.

[0026] 1 to 6 , a method for processing a workpiece using a selective laser melting device according to an embodiment of the present invention will be described.

[0027] According to an embodiment of the present invention, a method for processing a workpiece using a selective laser melting device includes a substrate for supporting the workpiece to be processed. The method includes:

[0028] Placing the workpieces to be processed distributed in an array on the carrying area of ​​the carrying substrate;

[0029] During the laser scanning process of the workpiece to be processed, the workpiece to be processed is purged with gas;

[0030] The gas flow direction is parallel to the carrier 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 is adjustable, and the direction of the laser scanning path can be parallel to the carrier substrate. During laser scanning of the workpiece, the direction of the laser scanning path can be adjusted, and the gas flow direction can change with the direction of the laser scanning path, while the first angle can remain fixed.

[0031] According to the method for processing a workpiece using a laser selective melting device in an embodiment of the present invention, an angle can be formed between the direction of the laser scanning path and the direction of the gas flow, and the direction of the laser scanning path can be adjusted. During the process of laser scanning the workpiece to be processed, gas can be blown toward the workpiece to be processed. The gas can carry away by-products such as spatter and metal vapor generated at the moment of formation of a tiny molten pool, so as to blow the by-products away from the workpiece to be processed, prevent the by-products from falling on the workpiece to be processed, reduce the impact of the by-products on the quality of the workpiece to be processed, and improve the processing quality.

[0032] In some embodiments, the first angle may be greater than or equal to 0 degrees and less than 180 degrees. For example, the first angle may be greater than or equal to 30 degrees and less than 120 degrees. In the process of laser scanning the workpiece to be processed, the gas can carry away byproducts such as spatter and metal vapor generated at the moment the tiny molten pool is formed. The first angle may be greater than or equal to 0 degrees and less than 90 degrees, which is conducive to blowing the byproducts away from the area on the workpiece to be processed where the laser has scanned, so that the byproducts will not fall on the area where the laser has scanned, thereby reducing the impact of the byproducts. In some embodiments, before using gas to purge the workpiece to be processed, it may also include: equalizing the flow of the gas. By equalizing the flow of the gas, the gas distribution can be made more uniform, thereby improving the uniformity of gas distribution on different workpieces to be processed.

[0033] Optionally, the gas may be an inert gas. The inert gas may include at least one of nitrogen and argon. For example, the inert gas may be nitrogen or argon. The inert gas may protect the workpiece from being oxidized.

[0034] Optionally, during the laser scanning process of the additive layers of the workpiece to be processed, the laser scanning paths of adjacent additive layers are different, which can improve the forming effect between the layers and improve the forming quality.

[0035] During the additive manufacturing process, the laser scanning path of each layer will be offset by a certain angle from the laser scanning path of the previous layer, thereby avoiding manufacturing defects caused by peaks and valleys between passes due to laser scanning on the same path. For example, when scanning the current layer, the laser scanning path can be as shown in Figure 4. When scanning the next layer, it will be scanned with a 5° offset from the previous layer, and the laser scanning path can be as shown in Figure 5. This will improve the forming effect between each layer and improve the forming quality.

[0036] 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 based on actual conditions to improve the forming effect between layers and improve the forming quality.

[0037] According to some embodiments, during laser scanning of additive layers of a workpiece to be processed, the angles between the directions of the laser scanning paths of adjacent additive layers and the gas flow direction are the same.

[0038] During the forming process of each layer, 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°, the scanning forming has the optimal forming effect as shown in Figure 6. Currently, in powder 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 entity 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 be rotated by a certain angle, such as 5°. At this time, the angle between the laser scanning path and the gas flow direction becomes 40°, and the forming effect of this angle is not as good as 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.

[0039] Optionally, during the laser scanning process of the additive layer of the workpiece to be processed, the angle between the laser scanning path and the gas flow direction may be 30-60°. For example, the angle between the laser scanning path and the gas flow direction may be 45°. The specific angle may be selected based on actual needs.

[0040] In some embodiments, the angle between the gas flow direction and the lengthwise direction of the row of workpieces to be processed is acute or obtuse. For example, gas is blown toward the workpieces from a side edge of the carrier substrate, with the gas flow direction parallel to the carrier substrate. The angle between the gas flow direction and the lengthwise direction of the row of workpieces to be processed is acute or obtuse. The angle between the gas flow direction and the lengthwise direction of the row of workpieces to be processed can be greater than or equal to 60° and less than 90°. By blowing gas toward the workpieces, byproducts such as spatter and metal vapor generated during the formation of the micromolten pool can be carried away, thereby blowing the byproducts away from the workpieces and preventing them from landing on them. The gas can be air or an inert gas, such as argon or nitrogen. As shown in Figure 1, the gas flow direction is parallel to the lengthwise direction of the row, making it easier for byproducts blown away from the next row to land on the workpieces in the previous row. As shown in Figure 2, the gas flow direction is acute or obtuse, and the gas flow is tilted, making it less likely that byproducts blown away from the next row will land on the workpieces in the previous row.

[0041] In some embodiments, during laser scanning of an additive layer on a workpiece, the path from the workpiece in row n and column m to the workpiece in row n-2 and column m+1 is a first path, and the path from the workpiece in row n and column m to the workpiece in row n+1 is a second path. The angle between the first path and the length of the column m is a first angle, and the angle between the second path and the length of the column m is a second angle. The angle between the gas flow direction and the length 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 toward the workpieces to blow byproducts away from the workpieces, the byproducts land in the area between the two workpieces, preventing them from landing on the workpieces.

[0042] As shown in FIG3 , 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 a first path s1, and the path from the workpiece in row 8, column 1 to the workpiece in row 8, column 2 is a second path s2. The angle between the first path s1 and the length direction s of the column 1 is a first angle, and the angle between the second path s2 and the length direction s of the column 1 is a 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 direction s1 or in a direction between the directions s1 and s2. The gas flow direction can increase the distance between the two workpieces to be processed. By blowing gas toward the workpieces to blow byproducts away from the workpieces, the byproducts fall into the area between the two workpieces to be processed, preventing the byproducts from falling on the workpieces to be processed. During the application process, the workpieces to be processed can be distributed in an array on a 400mm*400mm carrier substrate. The spacing between adjacent workpieces in each row can be 5-12mm, for example, 10mm. When laser printing is turned on, the inert protective gas can be blown out in the direction shown in Figure 2.

[0043] In some embodiments, the carrier substrate has multiple distribution areas, and at least two of the distribution areas have different distribution densities of workpieces to be processed. The distribution areas with different distribution densities of workpieces to be processed have different gas flow directions. The workpieces to be processed with different distribution densities have different spacing between adjacent workpieces, and thus require different gas flow directions.

[0044] Optionally, the method may further include: collecting the gas after purging the workpiece to be processed, filtering the collected gas and reusing it to purge the workpiece to be processed.

[0045] The gas after purging the workpiece carries by-products, which can be removed by filtering. The filtered air flow enters the air inlet pipe again, so that the gas can be recycled.

[0046] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for processing a workpiece using a laser selective melting device, wherein the laser selective melting device comprises a supporting substrate for supporting the workpiece to be processed, characterized in that: The method comprises: Placing the workpieces to be processed distributed in an array on the carrying area of ​​the carrying substrate; During the laser scanning process of the workpiece to be processed, the workpiece to be processed is purged with gas; The gas flow direction of the gas is parallel to the carrier substrate, the angle between the direction of the laser scanning path and the gas flow direction is a first angle, and the direction of the laser scanning path is adjustable.

2. The method according to claim 1, characterized in that The first angle is greater than or equal to 0 degrees and less than 180 degrees; and / or Before using gas to purge the workpiece to be processed, the method further includes: uniformly flowing the gas; and / or the gas is an inert gas.

3. The method according to claim 1, characterized in that During the laser scanning process of the additive layers of the workpiece to be processed, the laser scanning paths of adjacent additive layers are different.

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

5. The method according to claim 3, characterized in that: During the laser scanning process of the additive layers of the workpiece to be processed, the angles between the directions of the laser scanning paths of adjacent additive layers and the gas flow direction are the same.

6. The method according to claim 3, characterized in that During the laser scanning of the additive layer of the workpiece to be processed, the angle between the direction of the laser scanning path and the gas flow direction is 30-60°.

7. The method according to claim 1, characterized in that The angle between the gas flow direction and the length direction of the row of the workpieces to be processed is an acute angle or an obtuse angle.

8. The method according to claim 1 or 7, characterized in that: During the laser scanning process of the additive layer of the workpiece to be processed, the path from the workpiece to be processed in the nth row and mth column to the workpiece to be processed in the n-2th row and m+1th column is the first path, and the path from the workpiece to be processed in the nth row and mth column to the workpiece to be processed in the nth row and m+1th column is the second path. The angle between the first path and the length direction of the mth column is the first angle, the angle between the second path and the length direction of the mth column is the second angle, and 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.

9. The method according to claim 1, characterized in that: The carrier substrate has a plurality of distribution areas, the distribution densities of the workpieces to be processed in at least two of the distribution areas are different, and the gas flow directions of the gas in the distribution areas with different distribution densities of the workpieces to be processed are different.

10. The method according to claim 9, characterized in that Also includes: The gas after purging the workpiece to be processed is collected, and the collected gas is filtered and reused for purging the workpiece to be processed.

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