A laser selective melting device and method for printing small cross-section size parts

Abstract

This invention relates to a laser selective melting apparatus and method for printing small cross-section parts, belonging to the field of metal additive manufacturing. It includes: a forming cavity (1), a powder spreading mechanism (2), a forming table (3), a lifting mechanism (4), a powder sieving mechanism (5), a conveying mechanism (7), a lifting mechanism (8), and an upper powder feeding mechanism (9); the forming cavity (1) is equipped with the powder spreading mechanism (2), and the forming table (3) is located below the powder spreading mechanism (2); the top of the lifting mechanism (4) is connected to the forming cavity (1), and the bottom of the lifting mechanism (4) is connected to the powder sieving mechanism (5); the output end of the powder sieving mechanism (5) is connected to the conveying mechanism (7), the powder outlet of the conveying mechanism (7) is connected to the powder inlet of the lifting mechanism (8), and the powder outlet of the lifting mechanism (8) is connected to the upper powder feeding mechanism (9); by designing the equipment's tool holder and substrate, powder spreading areas of different sizes and corresponding substrates can be obtained, improving powder utilization efficiency and achieving more efficient printing.

Description

Technical Field

[0001] This invention belongs to the field of metal additive manufacturing, and specifically relates to a laser selective melting device and method for printing small cross-section parts. Background Technology

[0002] Selective laser melting (SLM) is an important branch of metal additive manufacturing. This technology can produce metal parts with complex shapes, excellent overall performance, and good surface quality, characterized by high efficiency, precision, and flexibility. In the SLM process, a three-dimensional digital model of the workpiece is first created and saved in a specific format (usually STL). Then, specialized slicing software processes the model, slicing it according to a specified layer thickness to obtain the contour of each layer's cross-section. Next, a scanning path is filled within each contour to determine the trajectory and sequence of laser irradiation. Control software controls the actions of the actuators (such as a laser scanning system) according to the path, completing the processing layer by layer. During the forming process, the equipment lays powder layer by layer according to the parameters set for the part slices. When the powder feeding mechanism delivers a fixed amount of powder into the equipment as instructed, the powder spreading mechanism evenly spreads the powder onto the substrate. In existing SLM equipment, the substrate is a complete block of metal material, and its size is often the maximum size of the formable part. Therefore, the amount of powder used in a single print is determined by the substrate area and the height of the part, rather than by the actual printing area of ​​the part. For parts with a single-print forming surface size much smaller than the substrate size, a large amount of powder is typically required to fully coat the substrate surface. This not only significantly increases the initial production cost, but also, since the internal dust removal system cannot guarantee the complete removal of contaminants such as smoke generated during the printing process, feeding too much powder can lead to smoke pollution and reduced forming quality. Therefore, there is an urgent need to provide a laser selective melting device and method for printing and processing small cross-sectional parts, and for controlling the amount of printing powder. Summary of the Invention

[0003] (a) Technical problems to be solved

[0004] The technical problem to be solved by the present invention is how to provide a laser selective melting device and method for printing small cross-sectional parts, so as to solve the problem of low powder utilization efficiency in the printing process of existing melting devices.

[0005] (II) Technical Solution

[0006] To solve the above-mentioned technical problems, the present invention proposes a laser selective melting device for printing small cross-section parts, comprising: a forming cavity 1, a powder spreading mechanism 2, a forming table 3, a lifting mechanism 4, a powder sieving mechanism 5, a conveying mechanism 7, a lifting mechanism 8, and a powder feeding mechanism 9.

[0007] The forming cavity 1 is provided with a powder spreading mechanism 2, and a forming platform 3 is provided below the powder spreading mechanism 2;

[0008] The top of the lifting mechanism 4 is connected to the forming cavity 1, and the bottom of the lifting mechanism 4 is connected to the powder screening mechanism 5.

[0009] The output end of the sieving mechanism 5 is connected to the conveying mechanism 7, the powder outlet of the conveying mechanism 7 is connected to the powder inlet of the lifting mechanism 8, and the powder outlet of the lifting mechanism 8 is connected to the upper powder feeding mechanism 9.

[0010] The powder spreading mechanism 2 includes: a knife holder 201, a powder spreading baffle 202, a ball screw 204, a stepper motor 206, a coupling 207, a slot 208, a pressure plate 209, and a base plate;

[0011] One powder spreading baffle 202 is provided on each side, symmetrically and inclinedly laid on the base plate. Each powder spreading baffle 202 is provided with a screw nut 203. The ball screw 204 passes through the screw nut 203. The end of the ball screw 204 is connected to the coupling 207. The end of the powder spreading baffle 202 is connected to the knife holder 201 through the slot 208. The powder spreading baffle 202 is connected to the pressure plate 209 by bolts 210.

[0012] The motor 206 is connected to the tool holder 201 via the motor connecting plate 205, and the motor 206 is connected to the ball screw 204 via the coupling 207.

[0013] The forming platform 3 includes: a large substrate 301, a small substrate 302, an upper top plate 303, bolts 304, a sealing gasket 305, a sealing gasket 306, and a cylinder 307.

[0014] The large substrate 301 has a threaded hole on its upper surface and is connected to the small substrate 302 and the upper top plate 303 by bolts 304.

[0015] The upper top plate 303 is disposed below the bottom plate, and the laser selective melting device is provided between the upper top plate 303 and the side wall of the small substrate 302. The device also includes a waste collection tank 6.

[0016] The powder screening mechanism 5 has a powder inlet and two powder outlets. The powder inlet is connected to the powder drop outlet 101 of the forming cavity 1, the first powder outlet is connected to the powder inlet of the conveying mechanism 7, and the other powder outlet is connected to the powder inlet of the waste residue collection tank 6.

[0017] The melting device further includes: a laser system 10;

[0018] The laser system 10 is disposed above the forming cavity 1, and the light output port of the laser system 10 is configured to face the forming stage 3.

[0019] The laser selective melting device further includes: a forming table replacement device 11;

[0020] The forming table replacement device 11 includes: a first control motor 1101, a first ball screw 1102, a first screw nut 1103, a push plate 1104, a housing 1105, a second ball screw 1106, a second screw nut 1107, and a second control motor 1108.

[0021] The second control motor 1108 is connected to the second ball screw 1106 via the second lead screw nut 1107, which drives the spare forming table in the housing 1105 to rise to a certain height. The first control motor 1101 is connected to the first ball screw 1102 via the first lead screw nut 1103, which drives the push plate 1104 to push the spare forming table into the forming cavity 1.

[0022] The powder feeding mechanism 9 includes: a butterfly valve 901, a manual powder feeding port 902, a powder storage tank 903, a circulating powder feeding port 904, and a powder feeding roller 905;

[0023] A manual powder feeding port 902 is provided above the powder storage tank 903. A butterfly valve 901 is provided above the manual powder feeding port 902. The butterfly valve 901 controls the opening and closing of the manual powder feeding port 902. A circulating powder feeding port 904 is provided on the side wall of the powder storage tank 903. The circulating powder feeding port 904 is connected to the powder outlet of the lifting mechanism 8. A powder feeding roller 905 is provided below the powder storage tank 903. The powder feeding roller 905 is used to feed the powder from the powder storage tank 903 into the knife holder 201, and then spread the powder to the powder spreading area through the powder spreading baffle 202.

[0024] A laser selective melting method for printing small cross-section parts, the melting method being implemented using a melting device, specifically including the following steps:

[0025] Step 1: Determine the required substrate size according to the part to be printed, add an appropriate amount of powder to the powder feeding mechanism 9 through the manual powder feeding port 902, and put multiple substrates into the substrate changing mechanism 11.

[0026] Step 2: By controlling the motor 206 to drive the ball screw 204 and screw nut 203 to drive the powder spreading baffle 202 to the set position, the part model is imported into the printing equipment, and the part is printed after inert gas is introduced.

[0027] Step 3: During the printing process, excess powder falls from the powder drop outlet of the forming cavity 1 into the powder screening mechanism 5. The powder processed by the powder screening mechanism 5 enters the conveying mechanism 7 through the first powder outlet. The conveying mechanism 7 conveys the powder to the lifting mechanism 8, and then enters the powder storage tank 903 through the circulating powder feeding port 904. It is then fed into the knife holder for recycling through the powder feeding roller 905. The waste residue after screening enters the waste residue collection tank 6.

[0028] Step 4: After printing is completed, the forming table 3 enters the forming table replacement device 11. The second control motor 1108 is connected to the second ball screw 1106 through the second lead screw nut 1107, which drives the spare forming table in the housing 1105 to rise to a certain height. The first control motor 1101 is connected to the first ball screw 1102 through the first lead screw nut 1103, which drives the push plate 1104 to push the spare forming table into the forming cavity 1. An appropriate amount of powder is added to the powder feeding mechanism 9 through the manual powder feeding port 902, and processing can continue, realizing continuous printing without stopping the machine.

[0029] In step 2, when it is necessary to adjust the printing area according to the part, the motor 206 can drive the powder spreading baffle 202 to reach the predetermined position again, and the powder spreading baffle 202 will concentrate the powder spreading area in the middle, reducing the powder feeding area.

[0030] (III) Beneficial Effects

[0031] Compared with the prior art, the present invention has the following beneficial effects: the added powder spreading baffle can make the powder feeding amount half or even lower than the original amount through system settings during powder feeding, and the powder is basically concentrated in the designed area. This can effectively solve the waste caused by excessive powder use and save material and time costs before and after printing.

[0032] Based on this, the equipment structure was redesigned, and an added powder sieving mechanism was added to separate excess powder and some of the dust particles generated during printing. The clean powder is then returned to the upper powder feeding mechanism via a conveying and lifting mechanism, achieving powder recycling. The added forming table replacement device ensures the continuity of printing. Attached Figure Description

[0033] Figure 1 This is a structural diagram of the present invention;

[0034] Figure 2 This is a schematic diagram of the powder spreading mechanism;

[0035] Figure 3 This is a schematic diagram of the forming stage;

[0036] Figure 4 This is a schematic diagram of the powder delivery structure;

[0037] Figure 5 This is a schematic diagram of the forming table replacement device;

[0038] Figure 6 This is a flowchart of the melting method. Detailed Implementation

[0039] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0040] To address the aforementioned problems, this embodiment provides a laser selective melting apparatus for printing small cross-sectional parts, such as... Figures 1-6 As shown, it includes: a forming cavity 1, a powder spreading mechanism 2, a forming table 3, a lifting mechanism 4, a powder sieving mechanism 5, a conveying mechanism 7, a lifting mechanism 8, and an upper powder feeding mechanism 9.

[0041] The forming cavity 1 is provided with a powder spreading mechanism 2, and a forming platform 3 is provided below the powder spreading mechanism 2;

[0042] The top of the lifting mechanism 4 is connected to the forming cavity 1, and the bottom of the lifting mechanism 4 is connected to the powder screening mechanism 5.

[0043] The output end of the sieving mechanism 5 is connected to the conveying mechanism 7, the powder outlet of the conveying mechanism 7 is connected to the powder inlet of the lifting mechanism 8, and the powder outlet of the lifting mechanism 8 is connected to the upper powder feeding mechanism 9.

[0044] The powder spreading mechanism 2 includes: a knife holder 201, a powder spreading baffle 202, a ball screw 204, a stepper motor 206, a coupling 207, a slot 208, a pressure plate 209, and a base plate;

[0045] One powder spreading baffle 202 is provided on each side, symmetrically and inclinedly laid on the base plate. Each powder spreading baffle 202 is provided with a screw nut 203. The ball screw 204 passes through the screw nut 203. The end of the ball screw 204 is connected to the coupling 207. The end of the powder spreading baffle 202 is connected to the knife holder 201 through the slot 208. The powder spreading baffle 202 is connected to the pressure plate 209 by bolts 210.

[0046] The motor 206 is connected to the tool holder 201 via the motor connecting plate 205, and the motor 206 is connected to the ball screw 204 via the coupling 207.

[0047] The forming platform 3 includes: a large substrate 301, a small substrate 302, an upper top plate 303, bolts 304, a sealing gasket 305, a sealing gasket 306, and a cylinder 307.

[0048] The large substrate 301 has a threaded hole on its upper surface and is connected to the small substrate 302 and the upper top plate 303 by bolts 304.

[0049] The upper top plate 303 is disposed below the bottom plate, and the laser selective melting device is provided between the upper top plate 303 and the side wall of the small substrate 302. The device also includes a waste collection tank 6.

[0050] The powder screening mechanism 5 has a powder inlet and two powder outlets. The powder inlet is connected to the powder drop outlet 101 of the forming cavity 1, the first powder outlet is connected to the powder inlet of the conveying mechanism 7, and the other powder outlet is connected to the powder inlet of the waste residue collection tank 6.

[0051] The melting device further includes: a laser system 10;

[0052] The laser system 10 is disposed above the forming cavity 1, and the light output port of the laser system 10 is configured to face the forming stage 3.

[0053] The laser selective melting device further includes: a forming table replacement device 11;

[0054] The forming table replacement device 11 includes: a first control motor 1101, a first ball screw 1102, a first screw nut 1103, a push plate 1104, a housing 1105, a second ball screw 1106, a second screw nut 1107, and a second control motor 1108.

[0055] The second control motor 1108 is connected to the second ball screw 1106 via the second lead screw nut 1107, which drives the spare forming table in the housing 1105 to rise to a certain height. The first control motor 1101 is connected to the first ball screw 1102 via the first lead screw nut 1103, which drives the push plate 1104 to push the spare forming table into the forming cavity 1.

[0056] The powder feeding mechanism 9 includes: a butterfly valve 901, a manual powder feeding port 902, a powder storage tank 903, a circulating powder feeding port 904, and a powder feeding roller 905;

[0057] A manual powder feeding port 902 is provided above the powder storage tank 903. A butterfly valve 901 is provided above the manual powder feeding port 902. The butterfly valve 901 controls the opening and closing of the manual powder feeding port 902. A circulating powder feeding port 904 is provided on the side wall of the powder storage tank 903. The circulating powder feeding port 904 is connected to the powder outlet of the lifting mechanism 8. A powder feeding roller 905 is provided below the powder storage tank 903. The powder feeding roller 905 is used to feed the powder from the powder storage tank 903 into the knife holder 201, and then spread the powder to the powder spreading area through the powder spreading baffle 202.

[0058] A laser selective melting method for printing small cross-section parts, the melting method being implemented using a melting device, such as... Figure 6 As shown, the specific steps include:

[0059] Step 1: Determine the required substrate size according to the part to be printed, add an appropriate amount of powder to the powder feeding mechanism 9 through the manual powder feeding port 902, and put multiple substrates into the substrate changing mechanism 11.

[0060] Step 2: By controlling the motor 206 to drive the ball screw 204 and screw nut 203 to drive the powder spreading baffle 202 to the set position, the part model is imported into the printing equipment, and the part is printed after inert gas is introduced.

[0061] Step 3: During the printing process, excess powder falls from the powder drop outlet of the forming cavity 1 into the powder screening mechanism 5. The powder processed by the powder screening mechanism 5 enters the conveying mechanism 7 through the first powder outlet. The conveying mechanism 7 conveys the powder to the lifting mechanism 8, and then enters the powder storage tank 903 through the circulating powder feeding port 904. It is then fed into the knife holder for recycling through the powder feeding roller 905. The waste residue after screening enters the waste residue collection tank 6.

[0062] Step 4: After printing is completed, the forming table 3 enters the forming table replacement device 11. The second control motor 1108 is connected to the second ball screw 1106 through the second lead screw nut 1107, which drives the spare forming table in the housing 1105 to rise to a certain height. The first control motor 1101 is connected to the first ball screw 1102 through the first lead screw nut 1103, which drives the push plate 1104 to push the spare forming table into the forming cavity 1. An appropriate amount of powder is added to the powder feeding mechanism 9 through the manual powder feeding port 902, and processing can continue, realizing continuous printing without stopping the machine.

[0063] In step 2, when it is necessary to adjust the printing area according to the part, the motor 206 can drive the powder spreading baffle 202 to reach the predetermined position again, and the powder spreading baffle 202 will concentrate the powder spreading area in the middle, reducing the powder feeding area.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A laser selective melting apparatus for printing small cross-section parts, characterized in that, include: Forming cavity (1), powder spreading mechanism (2), forming table (3), lifting mechanism (4), powder sieving mechanism (5), conveying mechanism (7), lifting mechanism (8), and powder feeding mechanism (9); The forming cavity (1) is provided with a powder spreading mechanism (2), and a forming platform (3) is provided below the powder spreading mechanism (2); The top of the lifting mechanism (4) is connected to the forming cavity (1), and the bottom of the lifting mechanism (4) is connected to the powder screening mechanism (5). The output end of the sieving mechanism (5) is connected to the conveying mechanism (7), the powder outlet of the conveying mechanism (7) is connected to the powder inlet of the lifting mechanism (8), and the powder outlet of the lifting mechanism (8) is connected to the upper powder feeding mechanism (9). The powder spreading mechanism (2) includes: a knife holder (201), a powder spreading baffle (202), a ball screw (204), a stepper motor (206), a coupling (207), a slot (208), a pressure plate (209), and a base plate; One powder spreading baffle (202) is provided on each side, symmetrically and inclinedly laid on the base plate. Each powder spreading baffle (202) is provided with a screw nut (203). The ball screw (204) passes through the screw nut (203). The end of the ball screw (204) is connected to the coupling (207). The end of the powder spreading baffle (202) is connected to the knife holder (201) through the slot (208). The powder spreading baffle (202) is connected to the pressure plate (209) by bolts. The stepper motor (206) is connected to the tool holder (201) via the motor connecting plate (205), and the stepper motor (206) is connected to the ball screw (204) via the coupling (207). The forming stage (3) includes: a large substrate (301), a small substrate (302), an upper top plate (303), bolts, a first sealing gasket (305), a second sealing gasket (306), and a cylinder (307). The large substrate (301) has threaded holes on its upper surface and is connected to the small substrate (302) and the upper top plate (303) by bolts; The upper top plate (303) is located below the bottom plate. A first sealing gasket (305) is provided between the upper top plate (303) and the side wall of the small base plate (302). A second sealing gasket (306) is provided between the end of the upper top plate (303) and the cylinder body (307).

2. The laser selective melting apparatus for printing small cross-section parts as described in claim 1, characterized in that, The laser selective melting device also includes: a waste collection tank (6). The powder screening mechanism (5) has a powder inlet and two powder outlets. The powder inlet is connected to the powder drop outlet (101) of the forming cavity (1). The first powder outlet is connected to the powder inlet of the conveying mechanism (7), and the other powder outlet is connected to the powder inlet of the waste residue collection tank (6).

3. The laser selective melting apparatus for printing small cross-section parts as described in claim 1, characterized in that, The melting device also includes: a laser system (10); The laser system (10) is located above the forming cavity (1), and the light outlet of the laser system (10) is set to face the forming stage (3).

4. The laser selective melting apparatus for printing small cross-section parts as described in claim 1, characterized in that, The laser selective melting device further includes: a forming table replacement device (11). The forming table replacement device (11) includes: a first control motor (1101), a first ball screw (1102), a first screw nut (1103), a push plate (1104), a housing (1105), a second ball screw (1106), a second screw nut (1107), and a second control motor (1108); The second control motor (1108) is connected to the second ball screw (1106) through the second lead screw nut (1107) to drive the spare forming table in the housing (1105) to rise to a certain height. The first control motor (1101) is connected to the first ball screw (1102) through the first lead screw nut (1103) to drive the push plate (1104) to push the spare forming table into the forming cavity (1).

5. The laser selective melting apparatus for printing small cross-section parts as described in claim 1, characterized in that, The powder feeding mechanism (9) includes: a butterfly valve (901), a manual powder feeding port (902), a powder storage tank (903), a circulating powder feeding port (904), and a powder feeding roller (905). The powder storage tank (903) has a manual powder feeding port (902) above it. A butterfly valve (901) is provided above the manual powder feeding port (902). The butterfly valve (901) controls the opening and closing of the manual powder feeding port (902). A circulating powder feeding port (904) is provided on the side wall of the powder storage tank (903). The circulating powder feeding port (904) is connected to the powder outlet of the lifting mechanism (8). A powder feeding roller (905) is provided below the powder storage tank (903). The powder feeding roller (905) is used to feed the powder from the powder storage tank (903) into the knife holder (201), and then spread the powder to the powder spreading area through the powder spreading baffle (202).

6. A laser selective melting method for printing small cross-section parts, characterized in that, The melting method is implemented based on the laser selective melting apparatus of claim 5, and specifically includes the following steps: Step 1: Determine the required substrate size according to the part to be printed, add an appropriate amount of powder through the manual powder feeding port (902) to the powder feeding mechanism (9), and put multiple substrates into the substrate replacement mechanism. Step 2: By controlling the stepper motor (206) to drive the ball screw (204) and screw nut (203) to drive the powder spreading baffle (202) to the set position, the part model is imported into the printing equipment, and the part is printed after inert gas is introduced. Step 3: During the printing process, excess powder falls from the powder drop port of the forming cavity (1) into the powder screening mechanism (5). The powder processed by the powder screening mechanism (5) enters the conveying mechanism (7) through the first powder outlet. The conveying mechanism (7) conveys the powder to the lifting mechanism (8), and then enters the powder storage tank (903) through the circulating powder feeding port (904). It is then fed into the knife holder for recycling through the powder feeding roller (905). The waste residue after screening enters the waste residue collection tank (6). Step 4: After printing is completed, the forming table (3) enters the forming table replacement device (11). The second control motor (1108) is connected to the second ball screw (1106) through the second lead screw nut (1107) to drive the spare forming table in the box (1105) to rise to a certain height. The first control motor (1101) is connected to the first ball screw (1102) through the first lead screw nut (1103) to drive the push plate (1104) to push the spare forming table into the forming cavity (1). An appropriate amount of powder is added to the powder feeding mechanism (9) through the manual powder feeding port (902) so that processing can continue and continuous printing without stopping can be achieved.

7. The laser selective melting method for printing small cross-section parts as described in claim 6, characterized in that, In step 2, when it is necessary to adjust the printing area according to the part, the powder spreading baffle (202) can be driven by the stepper motor (206) to reach the predetermined position again, and the powder spreading baffle (202) will concentrate the powder spreading area in the middle and reduce the powder feeding area.

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