Selective laser melting vertical gradient material printing method based on layered partition plate

Abstract

The invention discloses a selective laser melting vertical gradient material printing method based on a layered partition plate, and belongs to the technical field of additive manufacturing. The method comprises the following steps: (1) establishing a three-dimensional model with different material attributes in the vertical direction, and generating corresponding slice data; (2) the powder with at least two different components is sequentially loaded into a powder supply cylinder according to a preset sequence, and the different powder is separated through partition plates; (3) after one kind of powder is printed, scraping all the residual powder of the component into a recovery cylinder by using a scraper, and paving; (4) adjusting the positions of the powder supply cylinder and the recovery cylinder, respectively ascending and descending for a certain thickness, and pushing the partition plate from the powder supply cylinder to the recovery cylinder by using a scraper; and (5) powder of different components is printed in sequence, and finally a sample piece with different component gradients in the vertical direction is formed. The method is easy to operate, capable of achieving one-time forming, low in cost, high in practicability and capable of preparing materials with different component gradients in the vertical direction, and equipment does not need to be improved.

Description

Technical Field

[0001] The invention relates to the field of additive manufacturing, and in particular to a selective laser melting vertical gradient material printing method based on a layered partition. Background Art

[0002] Additive Manufacturing (AM), also known as 3D printing, is an advanced manufacturing technology that manufactures three-dimensional objects by stacking materials layer by layer. Compared with traditional subtractive manufacturing, it has the characteristics of high material utilization and high design freedom. Among them, Selective Laser Melting (SLM) is a technology that uses high-energy lasers to melt and solidify metal powder layer by layer. Due to its high precision and high performance, it is widely used in aerospace, biomedicine, industrial manufacturing and other fields.

[0003] Existing SLM technology usually prints based on a single material, and has significant advantages in preparing parts with a single performance requirement, but has great limitations in preparing complex multifunctional parts that require different properties in different regions (such as high toughness and high ductility at one end, and high strength and high wear resistance at the other end). Therefore, studying how to conveniently and efficiently achieve SLM gradient multifunctional printing to meet the performance requirements of different regions of parts has great research significance and application value.

[0004] At present, there are several methods to achieve SLM vertical gradient material printing:

[0005] Printing in batches: Patent CN113664220B prints one powder at a time and repeats the printing of multiple different powders to achieve gradient material printing. This method is simple and does not require any improvements to the equipment and software, but multiple batches of printing make the production efficiency low and it is difficult to meet the needs of large-scale industrial production.

[0006] Multi-material powder supply system: Patent CN106735218B uses multiple powder supply devices to provide powders of different components. According to the program settings, each layer uses the corresponding type of powder to achieve gradient material printing. This method has high automation and printing efficiency, but requires customized equipment and is costly.

[0007] Real-time powder mixing system: Patent CN112517923B uses a robotic arm to perform real-time dynamic powder mixing in the SLM device to achieve gradient material printing. This method has a high degree of freedom in powder mixing, but the mixing accuracy and performance are difficult to guarantee, and the equipment cost is high.

[0008] In summary, although there are many methods to achieve SLM vertical gradient material printing, they generally have problems of low production efficiency or high equipment cost. Therefore, it is necessary to develop a SLM gradient material preparation method that does not require modification of existing equipment and can achieve efficient printing. Summary of the invention

[0009] The purpose of the present invention is to provide a selective laser melting vertical gradient material printing method based on a layered partition, in which different types of powders are loaded into a powder supply cylinder in sequence and separated by partitions, and powders of different compositions are printed in sequence, and the next type of powder is replaced by removing the partition to achieve SLM gradient material printing.

[0010] The technical solution of the present invention is as follows:

[0011] A method for printing vertical gradient materials by selective laser melting based on a layered partition comprises the following steps:

[0012] (1) Establishing a 3D model and slicing data. Use computer-aided design software to establish a 3D model of the target part, ensure that the model has a layered design with different material properties in the vertical direction, and use slicing software to decompose the 3D model into multiple horizontal layers and generate slicing data for each layer;

[0013] (2) Loading powder materials. According to the material properties designed by the model, at least two powders of different ingredients are loaded into the powder supply cylinder in a preset order, and the powders are flattened. Each type of powder is separated by a partition that is consistent with the cross-sectional size of the powder supply cylinder and the recovery cylinder and is resistant to high temperatures and does not stick to the powder, to ensure physical isolation between the powders and prevent powder mixing;

[0014] (3) Printing and powder recovery. Start the SLM equipment and select the first powder for printing. After each powder is printed, use a scraper to scrape all the remaining powder of that component into the recovery tank and flatten it according to the program setting, ensuring that the partition is flush with the top surface of the powder supply cylinder;

[0015] (4) Change to the next powder. Adjust the positions of the powder supply cylinder and the recovery cylinder so that they rise and fall by one partition thickness respectively, ensuring that the partition in the powder supply cylinder is completely exposed. Use a scraper to push the layered partition from the powder supply cylinder to the recovery cylinder to separate the different powders in the recovery cylinder.

[0016] (5) Print and shape layer by layer. Continue to select the next powder for printing and repeat steps 3 and 4 to ensure that the printed layer of each powder has a good transition with the previous layer. Print all the preset powder materials in sequence and finally form a sample with different component gradients in the vertical direction.

[0017] The advantages and beneficial effects of the present invention are:

[0018] (1) Low cost, no major equipment changes are required, and the present invention is applicable to most existing SLM equipment, thus avoiding the high cost caused by hardware upgrades.

[0019] (2) Improve production efficiency. The new baffle-type powder supply method reduces the time loss during multi-material switching and batch printing, greatly improving the printing efficiency of gradient materials.

[0020] (3) The process is simple, requiring only a few baffles and optimizing the procedure for changing powders. It does not involve complex program software development or path and parameter planning adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is a schematic diagram of a preparation process of a selective laser melting device used in a specific embodiment of the present invention;

[0022] Figure 2 2 is a schematic diagram of a second preparation process of a selective laser melting device used in a specific embodiment of the present invention;

[0023] Figure 3 3 is a schematic diagram of the preparation process of the selective laser melting device used in a specific embodiment of the present invention;

[0024] Figure 4 Schematic diagram of the preparation process of the selective laser melting device used in the specific embodiment of the present invention;

[0025] Figure 5 Schematic diagram of the preparation process of the selective laser melting equipment used in the specific embodiment of the present invention.

[0026] In the figure:

[0027] 1 scraper, 2 customized partition, 3 powder supply cylinder, 4 powder supply cylinder lifting platform, 5 forming part, 6 forming cylinder, 7 forming cylinder lifting platform, 8 recovery cylinder, 9 recovery cylinder lifting platform. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. However, the specific embodiments described herein are only used to explain the present invention, and the protection scope of the present invention is not limited thereto. It should also be noted that, for ease of description, only parts related to the present invention are provided in the accompanying drawings, rather than all structures.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "upper", "lower", "top surface" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or device referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are only used to distinguish in the description and have no special meaning.

[0030] The present invention provides a method for printing vertical gradient materials by selective laser melting based on a layered partition. AlSi10Mg powder with an average particle size of 37.1 μm and polygonal SiC particles with an average particle size of 5 μm are mixed, and a mechanical mixing intermittent ball milling method is adopted, argon gas protection is introduced, and the positive and negative rotations are alternated, the positive rotation is 20 minutes, the stop is 20 minutes, and the reverse rotation is 20 minutes, and the cycle is repeated. The ball milling speed is 200 r / min and the ball milling time is 6 hours. Aluminum-based silicon carbide composite materials with SiC mass fractions of 4%, 8%, and 12% are respectively configured, and are hereinafter expressed as AlSi10Mg-4%SiC, AlSi10Mg-8%SiC, and AlSi10Mg-12%SiC.

[0031] Specifically, Figure 1 As shown in the figure, 500g of each AlSi10Mg-12%SiC, AlSi10Mg-8%SiC, and AlSi10Mg-4%SiC powders are loaded into the powder feeding cylinder in the order shown in the figure. After each powder is filled and leveled, a customized 0.3mm thick polytetrafluoroethylene partition is placed on top to separate different powders.

[0032] The substrate is AlSi10Mg, and the substrate is preheated to 150°C before printing. Argon is used as the protective gas, and the oxygen content is controlled below 200ppm. The chessboard scanning method is adopted, and the scanning traces between adjacent chessboards rotate 90°, and the adjacent layers rotate 67° counterclockwise. The laser spot diameter is 40μm. The first powder AlSi10Mg-4% SiC is printed, and the laser power is set to 280W, the scanning speed is 1100mm / s, the scanning spacing is 0.11mm, the layer thickness is 30μm, and the printing size is 40×40×20mm.

[0033] Specifically, Figure 2 As shown in the figure, when the first powder AlSi10Mg-4%SiC is printed, the scraper is controlled by the program to push all the first powder in the powder supply cylinder into the recovery cylinder and flatten it, so that the top of the partition is flush with the top surface of the powder supply cylinder, and at the same time, the powder in the forming cylinder is flattened. The program is set to raise and lower the powder supply cylinder and the recovery cylinder by a partition thickness of 0.3mm respectively.

[0034] Specifically, Figure 3As shown, use a scraper to push the partition from the powder supply cylinder to the recovery cylinder and let it fall into the recovery cylinder to fill it, so that the top surface of the next powder in the powder supply cylinder is flush with the top surface of the powder supply cylinder, and the top surface of the partition in the recovery cylinder is flush with the top surface of the recovery cylinder, ready for printing the next powder.

[0035] Specifically, Figure 4 As shown, the second powder AlSi10Mg-8%SiC was printed, and the laser power was set to 320W, the scanning speed to 1100mm / s, the scanning spacing to 0.11mm, the layer thickness to 30μm, and the printing size to 40×40×20mm.

[0036] Specifically, Figure 5 As shown, repeat the above steps, move the second partition from the powder supply cylinder to the recovery cylinder, separate the powder in the recovery cylinder, print the third powder AlSi10Mg-12%SiC, set the laser power to 340W, the scanning speed to 1100mm / s, the scanning spacing to 0.11mm, the layer thickness to 30μm, and the printing size to 40×40×20mm. Finally, the AlSi10Mg-4%SiC, AlSi10Mg-8%SiC, and AlSi10Mg-12%SiC gradient material printing is completed.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for printing vertical gradient materials by selective laser melting based on a layered partition, characterized in that: The method comprises the following steps: (1) establishing a three-dimensional model with different material properties in the vertical direction and generating corresponding slice data; (2) loading at least two powders of different components into a powder supply cylinder in a preset order, and separating the different powders with a partition; (3) after printing each type of powder, using a scraper to scrape all the remaining powder of the component into a recovery cylinder and flatten it; (4) adjusting the positions of the powder supply cylinder and the recovery cylinder, respectively raising and lowering them by a certain thickness, and using a scraper to push the partition from the powder supply cylinder to the recovery cylinder; (5) printing powders of different components in sequence, and finally forming a sample with different component gradients in the vertical direction.

2. The method for printing vertical gradient materials by selective laser melting based on layered partitions according to claim 1, characterized in that: The partition is made of high temperature resistant and powder non-sticky polytetrafluoroethylene material, has the same cross-sectional size as the powder supply cylinder and the recovery cylinder, and has a thickness controlled between 0.1 mm and 1 mm.

3. The method for printing vertical gradient materials by selective laser melting based on layered partitions according to claim 1, characterized in that: In step (2), a powder supply cylinder is used, and the filling amount of each powder is roughly determined according to a computer-controlled weighing system, and is loaded into the powder supply cylinder in sequence according to the order of material distribution in the slicing data. After one type of powder is loaded into the powder supply cylinder and leveled, a partition is placed on top to separate different types of powder.

4. The method for printing vertical gradient materials by selective laser melting based on layered partitions according to claim 1, characterized in that: In step (3), after each printing of a type of powder, the forming cylinder is controlled to remain stationary, the laser scanning is stopped, the powder supply cylinder and the recovery cylinder are respectively raised and lowered by one layer thickness, and the powder is scraped into the recovery cylinder with a scraper and flattened. This step is repeated until the partition rises to be flush with the top surface of the powder supply cylinder.

5. The method for printing vertical gradient materials by selective laser melting based on layered partitions according to claim 1, characterized in that: In step (4), the lifting height of the forming cylinder and the lowering height of the recovery cylinder are consistent with the thickness of the partition, ensuring that the partition is completely exposed in the powder supply cylinder and can be pushed into the recovery cylinder by a scraper to separate different types of powder in the recovery cylinder.

Images