Online collecting device for splashing particles in additive manufacturing

Abstract

The invention belongs to the field of additive manufacturing, and particularly relates to an online collecting device for splashing particles in additive manufacturing. The device comprises a lifting mechanism and a collecting assembly which are connected with each other, and the lifting mechanism is used for driving the collecting assembly to move up and down so as to change the distance between the collecting assembly and a powder bed; the collecting assembly comprises a first telescopic mechanism and a first collecting groove, the lifting mechanism is connected with the first collecting groove through the first telescopic mechanism, and the first telescopic mechanism can stretch out and draw back to change the relative position of the first collecting groove and the lifting mechanism; a slotted hole is formed in the first collecting groove, the slotted hole is in a long strip shape, the slotted hole is used for providing a hole channel for scanning laser to enter the powder bed, meanwhile, the slotted hole is further used for providing a hole channel for splashing particles to leave the powder bed, and the splashing particles fall on the first collecting groove through the slotted hole; when the laser acts on the powder bed, the distance between the groove hole and the surface of the powder bed is smaller than or equal to 4 mm.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing, specifically designing an online collection device for splashed particles in additive manufacturing. Background Technology

[0002] Laser powder bed fusion additive manufacturing (LBD) is an advanced digital manufacturing process that uses metal powder as raw material. A high-energy laser beam melts the powder layer by layer, and under computer control, complex three-dimensional parts are precisely assembled based on 3D model data. This technology can not only manufacture complex geometric structures that are difficult to achieve using traditional processing methods, but also significantly improve material utilization, reduce production costs, and enable flexible combinations of multiple materials. Therefore, it can meet personalized customization needs and has broad application prospects in many fields such as aerospace, medical, automotive, and mold making. Currently, it is in a phase of rapid development, with continuous equipment upgrades, in-depth material research and development, and steady progress in process optimization. It is gradually overcoming challenges such as improving precision and controlling defects, driving the manufacturing industry towards greater efficiency, precision, and personalization.

[0003] However, when a high-energy laser bombards a powder layer, the localized instantaneous high temperature causes the metal powder to melt or even vaporize rapidly. The recoil force of the metal vapor in the molten pool, fluctuations in the surface tension of the melt, or the thermal stress imbalance of incompletely melted particles can cause liquid metal droplets or solid powder particles to detach from the molten pool area, forming spatter particles. Firstly, spatter particles may deposit on the surface of the unmelted powder layer, disrupting the uniformity of the powder bed, leading to a decrease in subsequent powder spreading accuracy and interlayer bonding defects (such as porosity and cracks), thus resulting in performance degradation. Secondly, spatter particles may adhere to the laser optical system or the inner wall of the forming chamber, interfering with the laser energy transmission path, causing insufficient deposition laser power, and affecting processing stability. Thirdly, larger spatter droplets may adhere to the surface of the formed part, forming irregular protrusions or fusion defects, affecting surface quality and increasing the difficulty of post-processing. Therefore, the generation of spatter particles has a serious impact on the quality of additively formed parts, severely limiting its widespread application.

[0004] Controlling spatter is a common technical challenge facing the industry. Since spatter particles are unavoidable in laser powder bed fusion additive manufacturing, current efforts focus on multi-dimensional improvements, including laser parameter optimization (such as power density and scanning strategy), powder pretreatment (humidity and particle size sieving), and equipment airflow design (uniformity of the inert gas flow field), to mitigate spatter generation. However, due to the inherent principles of additive manufacturing, spatter is still a problem. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an online collection device for spatter particles in laser powder bed additive manufacturing. By collecting spatter particles in real time, the device collects them before they are generated but before they splash, thus preventing them from falling onto the powder bed and solving the problem of spatter affecting the forming quality.

[0006] In a first aspect, the present invention provides an online collection device for sputtering particles in a laser powder bed additive manufacturing process, comprising a lifting mechanism and a collection component connected to each other, wherein the lifting mechanism is used to drive the collection component to move up and down to change the distance between the collection component and the powder bed;

[0007] The collection component includes a first telescopic mechanism and a first collection slot. The lifting mechanism is connected to the first collection slot through the first telescopic mechanism. The first telescopic mechanism can extend and retract to change the relative position of the first collection slot and the lifting mechanism.

[0008] The first collection tank has slots, which are elongated and serve as channels for the scanning laser to enter the powder bed. At the same time, the slots also serve as channels for splashed particles to leave the powder bed, and the splashed particles fall onto the first collection tank through the slots.

[0009] When the laser interacts with the powder bed, the distance between the slot and the powder bed surface is ≤4mm.

[0010] According to an embodiment of the present invention, the first telescopic mechanism is rotatably connected to the lifting mechanism to change the angle of the first telescopic mechanism. Preferably, the first telescopic mechanism and the lifting mechanism are connected by a first rotating mechanism.

[0011] As an example, the lifting mechanism includes a fixed end and a movable end, the fixed end being used to connect to the additive manufacturing system, and the movable end being connected to a first telescopic mechanism.

[0012] According to an embodiment of the present invention, the first telescopic mechanism is rotatably connected to the first collection tank to change the angle of the first collection tank.

[0013] According to an embodiment of the present invention, a second rotating mechanism is provided on the first collection tank, and the first telescopic mechanism is connected to the first collection tank through the second rotating mechanism.

[0014] According to an embodiment of the present invention, both the first rotating mechanism and the second rotating mechanism include a rotating shaft, the first telescopic mechanism includes a fixed end and a movable end, the fixed end of the first telescopic mechanism is connected to the rotating shaft of the first rotating mechanism, and the movable end of the first telescopic mechanism is connected to the rotating shaft of the second rotating mechanism.

[0015] According to an embodiment of the present invention, the slot is elongated. When the first rotating mechanism and the second rotating mechanism rotate, they drive the first collecting tank to rotate. At the same time, the position of the slot also changes until the slot is parallel to the laser scanning path, ensuring that the laser scanning path falls into the slot. The splash particles generated by the laser scanning also leave the powder bed through this slot, and the splash particles fall onto the first collecting tank when they fall.

[0016] According to an embodiment of the present invention, a second telescopic mechanism is provided between the first collection tank and the second collection tank. The telescopic direction of the second telescopic mechanism is parallel to the slot direction of the first collection tank. The second telescopic mechanism includes a fixed end and a telescopic end. The fixed end of the second telescopic mechanism is connected to the first collection tank, and the telescopic end of the second telescopic mechanism is connected to the second collection tank.

[0017] According to an embodiment of the present invention, the second telescopic mechanism can drive the second collection groove to telescopically move along the groove direction of the first collection groove. By telescopically moving the second telescopic mechanism, the area of ​​the first collection groove and the second collection groove superimposed is changed, thereby changing the size of the exposed groove and thus controlling the laser scanning path.

[0018] According to an embodiment of the present invention, a rocking pin is provided on the second collection groove, the rocking pin being used for positioning so that the second collection groove can move along the groove hole direction under the action of the second telescopic mechanism.

[0019] According to an embodiment of the present invention, the swing pin engages with the slot of the first collecting groove, and in conjunction with the first rotating mechanism and the second rotating mechanism, the coordinate positions of the two ends of the slot can be changed. In the additive manufacturing process, the most critical thing is to keep the two ends of the laser scanning line within the line connecting the coordinate points of the two ends of the slot, that is, the laser scanning line enters the printing bed through the slot, which limits the laser scanning range. During the printing process, the splatter particles directly adhere to the bottom of the first collecting groove and the second collecting groove, or fall into the first collecting groove after passing through the slot.

[0020] Secondly, the present invention provides an additive manufacturing system having the above-mentioned device for online collection of splash particles, wherein the additive manufacturing system is provided with the device for online collection of splash particles.

[0021] According to an embodiment of the present invention, the additive manufacturing system includes a printing chamber, a printing bed is disposed at the bottom of the printing chamber, and a printing laser scanning assembly is disposed above the printing chamber; the device for collecting splatter particles online is disposed inside the printing chamber and is located between the printing laser scanning assembly and the printing bed.

[0022] According to an embodiment of the present invention, the fixed end of the lifting mechanism is fixed to the side wall of the printing chamber.

[0023] Thirdly, the present invention provides a method for printing using the above-mentioned online collection device, comprising the following steps:

[0024] S1. Based on the model scanning process planning and method, determine the laser scanning coordinate points A(x1,y1) and B(x2,y2) during operation, i.e., the coordinate points where the laser is transmitted onto the powder bed. Among them, coordinate A is closer to the second rotating mechanism, and coordinate B is closer to the swing pin. The rotation center coordinates of the second rotating mechanism are C(x01,y01), and the center coordinates of the swing pin are D(x02,y02). L1 is the distance between the rotation center of the second rotating mechanism 304 and the laser scanning coordinate point A when the splash collection is in operation. L2 is the distance between the center D of the swing pin and the laser scanning coordinate point B when the splash collection is in operation.

[0025] in,

[0026]

[0027] The coordinate of C is:

[0028] The coordinate of D is:

[0029] S2. Lower the collecting device until the distance between the first collecting tank and the powder bed surface is ≤4mm.

[0030] S3. Adjust the center coordinate of the second rotating mechanism to the C coordinate point; adjust the center coordinate of the swing pin to the D coordinate point; perform laser scanning of the current scan line area to collect the splash particles in the current scan line area.

[0031] According to an embodiment of the present invention, after step S3, step S4 is further included: repeating steps S1-S3 to complete the laser scanning of the current layer and collect the splashed particles.

[0032] According to an embodiment of the present invention, after step S4, step S5 is further included: raising the online collection device, laying additive manufacturing powder, and proceeding to the next layer of printing.

[0033] According to an embodiment of the present invention, after step S5, step S6 is further included: repeating steps S1-S5 until the number of layers to be printed. It is necessary to clean and collect the collected particles. The collection method includes known methods such as negative pressure adsorption and scraping to obtain the printed product.

[0034] Beneficial effects

[0035] The device for online collection of splash particles in this invention includes a lifting mechanism and a collection assembly connected to each other. The printing bed lifting mechanism drives the collection assembly to move up and down, thereby changing the distance between the collection assembly and the powder bed. The printing bed collection assembly includes a first telescopic mechanism and a first collection groove. The lifting mechanism is connected to the first collection groove through the first telescopic mechanism. The first telescopic mechanism of the printing bed can extend and retract to change the relative position between the first collection groove and the lifting mechanism. The first collection groove of the printing bed has slots, which are elongated and serve as channels for the scanning laser to enter the powder bed. Simultaneously, the slots also provide... The splatter particles leave the channels of the powder bed and fall into the first collection tank through the slots. This invention sets up an online collection device between the laser scanning component and the print bed. The laser enters the print bed again through the slots, and printing is carried out within a controllable range. The splatter particles only occur within the current range. Since the distance between the powder bed and the slots is small, the splatter particles fly out directly through the slots and fall into the collection tank, thereby avoiding the splatter particles from falling onto the powder bed surface. This eliminates quality problems such as pore defects and high oxide inclusions in the additive manufacturing process caused by splatter particles, greatly improves the quality and stability of additive manufacturing, and has significant economic value. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the additive manufacturing system in Embodiment 1 of the present invention;

[0037] Figure 2 for Figure 1 Top view.

[0038] Among them, 1-printing laser scanning assembly, 2-scanning laser, 3-splatter particle collector, 4-printing cavity, 5-printing bed; 301-lifting mechanism, 302-first rotating mechanism, 303-first telescopic mechanism, 304-second rotating mechanism, 305-first collection groove, 306-second collection groove, 307-second telescopic mechanism, 308-swing pin, 309-slot. Detailed Implementation

[0039] The structure of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0040] In the description of this invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] Example 1

[0043] See Figure 1 As shown, the present invention provides an online collection device for splatter particles in additive manufacturing, including a lifting mechanism 301, a first collection tank 305, and a second collection tank 306 arranged in sequence. The lifting mechanism 301 includes a fixed end and a movable end. The fixed end of the lifting mechanism 301 is used to fix the cavity wall of the additive manufacturing system, fixing the collection device inside the additive manufacturing system, and driving the first collection tank 305 and the second collection tank 306 to move up and down to avoid interference with the moving scraper. Specifically, the fixed end is used to fix the lifting mechanism 301 inside the printing chamber 4, and the fixing point is located between the printing laser scanning assembly 1 and the printing bed 5. The scanning laser 2 emitted by the printing laser scanning assembly 1 enters the printing bed 5 after passing through the collection device.

[0044] See Figure 2 As shown, the lifting mechanism 301 and the first collection tank 305 are connected by a first rotating mechanism 302, a first telescopic mechanism 303 and a second rotating mechanism 304 arranged in sequence. The first rotating mechanism 302 is located at the movable end of the lifting mechanism 301, and the second rotating mechanism 304 is located on the first collection tank 305. Specifically, the movable end provides a connection point for the first rotating mechanism 302, and the movable end itself is immovable. Both the first rotating mechanism 302 and the second rotating mechanism 304 include a rotating shaft. The first telescopic mechanism 303 includes a fixed end and a movable end. The fixed end of the first telescopic mechanism 303 is connected to the rotating shaft of the first rotating mechanism 302, and the movable end of the first telescopic mechanism 303 is connected to the rotating shaft of the second rotating mechanism 304.

[0045] The first collection tank 305 is provided with a hollowed-out slot 309, which is elongated. When the first rotating mechanism 302 and the second rotating mechanism 304 rotate, they drive the first collection tank 305 to rotate. At the same time, the position of the slot 309 also changes with the rotation of the first collection tank 305 until the slot 309 is parallel to the laser scanning path, ensuring that the laser scanning path falls into the slot 309. The splash particles generated by the laser scanning also leave the powder bed through this slot 309, and at the same time, the splash particles fall onto the first collection tank 305.

[0046] A second telescopic mechanism 307 is provided between the first collection groove 305 and the second collection groove 306. The telescopic direction of the second telescopic mechanism 307 is parallel to the direction of the slot 309 of the first collection groove 305. The second telescopic mechanism 307 includes a fixed end and a telescopic end. The fixed end of the second telescopic mechanism 307 is connected to the first collection groove 305, and the telescopic end of the second telescopic mechanism 307 is connected to the second collection groove 306. The second telescopic mechanism 307 can drive the second collection groove 306 to telescopically move along the direction of the slot 309 of the first collection groove 305. By telescopically extending and retracting the second telescopic mechanism 307, the overlapping area of ​​the first collection groove 305 and the second collection groove 306 is changed, thereby changing the size of the exposed slot 309 and thus controlling the laser scanning path.

[0047] A rocker pin 308 is provided on the second collection tank 306. The rocker pin 308 cooperates with the slot 309 of the first collection tank 305. Combined with the first rotating mechanism 302 and the second rotating mechanism 304, the coordinate positions of the two ends of the slot 309 can be changed. The rocker pin 308 is used for positioning, so that the second collection tank 306 can move along the direction of the slot 309 under the action of the second telescopic mechanism 307.

[0048] In the additive manufacturing process, the most critical thing is to keep both ends of the laser scanning line within the line connecting the coordinate points at both ends of the slot 309. That is, the laser scanning line enters the printing bed 5 through the slot 309, which limits the laser scanning range. During the printing process, the splatter particles directly adhere to the bottom of the first collection tank 305 and the second collection tank 306, or fall into the first collection tank 305 after passing through the slot 309.

[0049] After completing a single-layer or multi-layer laser scan, it is necessary to collect the splashed particles that fall into the first collection tank 305 and the second collection tank 306. The collection method adopts existing known methods, including but not limited to negative pressure adsorption, scraping, etc.

[0050] Example 2

[0051] This embodiment provides a method for printing using the online collection device of Embodiment 1, including the following steps:

[0052] 1. Based on the model scanning process planning and method, determine the laser scanning coordinate points A(x1,y1) and B(x2,y2) during operation, which are the coordinate points where the laser is transmitted onto the powder bed. Among them, coordinate A is closer to the second rotating mechanism 304, and coordinate B is closer to the swing pin 308. Let the rotation center coordinate of the second rotating mechanism 304 be C(x01,y01), and the center coordinate of the swing pin 308 be D(x02,y02). L1 is the distance between the rotation center of the second rotating mechanism 304 and the laser scanning coordinate point A when collecting splashes. L2 is the distance between the center D of the swing pin and the laser scanning coordinate point B when collecting splashes.

[0053] Based on the above conditions, the following can be calculated:

[0054]

[0055] The coordinate of C is:

[0056] The coordinate of D is:

[0057] 2. When the lifting mechanism 301 operates, it lowers the collecting device to near the surface of the powder bed 5, and the distance between the first collecting groove 305 and the surface of the powder bed 5 is ≤4mm.

[0058] 3. Drive the first rotating mechanism 302 and the first telescopic mechanism 303 so that the center coordinate of the second rotating mechanism 304 is at the above position C;

[0059] 4. Drive the second rotating mechanism 304 and the second telescopic mechanism 307 so that the center coordinate of the rocker pin 308 is at position D as calculated above;

[0060] 5. Perform laser scanning on the current scan line area to collect the splashed particles in the current scan line area;

[0061] 6. Repeat steps 1-4 to complete the laser scan of the current layer and collect the splashed particles;

[0062] 7. The lifting mechanism 301 operates, raising the collection device to lay additive manufacturing powder for printing on the next layer;

[0063] 8. Repeat steps 1-6 until a certain number of times. The collected particles need to be cleaned and collected. Collection methods include known methods such as negative pressure adsorption and scraping.

[0064] 9. Repeat steps 1-7 several times to complete the printing of the parts.

[0065] The specific embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above exemplary embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for online collection of spatter particles in a laser powder bed additive manufacturing process, characterized in that, The device includes a lifting mechanism and a collecting component connected to each other. The lifting mechanism is used to drive the collecting component to move up and down, so as to change the distance between the collecting component and the powder bed. The collection component includes a first telescopic mechanism and a first collection slot. The lifting mechanism is connected to the first collection slot through the first telescopic mechanism. The first telescopic mechanism can extend and retract to change the relative position of the first collection slot and the lifting mechanism. The first collection tank has slots, which are elongated and serve as channels for the scanning laser to enter the powder bed. At the same time, the slots also serve as channels for splashed particles to leave the powder bed, and the splashed particles fall onto the first collection tank through the slots. When the laser interacts with the powder bed, the distance between the slot and the powder bed surface is ≤4mm.

2. The device for online collection of spatter particles in laser powder bed additive manufacturing process according to claim 1, characterized in that, The first telescopic mechanism is rotatably connected to the lifting mechanism to change the angle of the first telescopic mechanism. Preferably, the first collection tank is provided with a second rotating mechanism, and the first telescopic mechanism is connected to the first collection tank through the second rotating mechanism.

3. The device for online collection of spatter particles in laser powder bed additive manufacturing process according to claim 2, characterized in that, Both the first rotating mechanism and the second rotating mechanism include a rotating shaft. The first telescopic mechanism includes a fixed end and a movable end. The fixed end of the first telescopic mechanism is connected to the rotating shaft of the first rotating mechanism, and the movable end of the first telescopic mechanism is connected to the rotating shaft of the second rotating mechanism.

4. The device for online collection of spatter particles in laser powder bed additive manufacturing process according to claim 2, characterized in that, The slot is elongated. When the first and second rotating mechanisms rotate, they drive the first collection tank to rotate. At the same time, the position of the slot also changes until the slot is parallel to the laser scanning path, ensuring that the laser scanning path falls into the slot. The splash particles generated by the laser scanning also leave the powder bed through this slot, and the splash particles fall onto the first collection tank when they fall.

5. The apparatus for online collection of spatter particles in laser powder bed additive manufacturing process according to any one of claims 1-3, characterized in that, A second telescopic mechanism is provided between the first collection tank and the second collection tank. The telescopic direction of the second telescopic mechanism is parallel to the direction of the slot of the first collection tank. The second telescopic mechanism includes a fixed end and a telescopic end. The fixed end of the second telescopic mechanism is connected to the first collection tank, and the telescopic end of the second telescopic mechanism is connected to the second collection tank.

6. The apparatus for online collection of spatter particles in laser powder bed additive manufacturing process according to claim 5, characterized in that, The second telescopic mechanism can drive the second collection groove to extend and retract along the groove direction of the first collection groove. By extending and retracting the second telescopic mechanism, the area of ​​the first collection groove and the second collection groove superimposed is changed, thereby changing the size of the exposed groove and thus controlling the laser scanning path.

7. The apparatus for online collection of spatter particles in laser powder bed additive manufacturing process according to claim 6, characterized in that, The second collection groove is provided with a rocking pin, which is used for positioning so that the second collection groove can move along the groove direction under the action of the second telescopic mechanism.

8. An additive manufacturing system having an apparatus for online collection of splash particles as described in any one of claims 1-7, characterized in that, The additive manufacturing system is equipped with a device for online collection of spatter particles. Preferably, the additive manufacturing system includes a printing chamber, a printing bed is disposed at the bottom of the printing chamber, and a printing laser scanning assembly is disposed above the printing chamber; the device for collecting splatter particles online is disposed inside the printing chamber and is located between the printing laser scanning assembly and the printing bed. Preferably, the fixed end of the lifting mechanism is fixed to the side wall of the printing chamber.

9. A method for printing using the online collection device according to any one of claims 1-7, characterized in that... Includes the following steps: S1. Based on the model scanning process planning and method, determine the laser scanning coordinate points A(x1,y1) and B(x2,y2) during operation, i.e., the coordinate points where the laser is transmitted onto the powder bed. Among them, coordinate A is closer to the second rotating mechanism, and coordinate B is closer to the swing pin. The rotation center coordinates of the second rotating mechanism are C(x01,y01), and the center coordinates of the swing pin are D(x02,y02). L1 is the distance between the rotation center of the second rotating mechanism 304 and the laser scanning coordinate point A when the splash collection is in operation. L2 is the distance between the center D of the swing pin and the laser scanning coordinate point B when the splash collection is in operation. in, The coordinate of C is: The coordinate of D is: S2. Lower the collecting device until the distance between the first collecting tank and the powder bed surface is ≤4mm; S3. Adjust the center coordinate of the second rotating mechanism to the C coordinate point; adjust the center coordinate of the swing pin to the D coordinate point; perform laser scanning of the current scan line area to collect the splash particles in the current scan line area.

10. The method for printing using the online collection device according to claim 9, characterized in that, After step S3, step S4 is also included: repeat steps S1-S3 to complete the laser scan of the current layer and collect the splashed particles. Preferably, after step S4, step S5 is also included: raising the online collection device, laying additive manufacturing powder, and proceeding to the next layer of printing. Preferably, after step S5, step S6 is also included: repeating steps S1-S5 until the number of layers to be printed. The collected particles need to be cleaned and collected. The collection method includes known methods such as negative pressure adsorption and scraping to obtain the printed product.

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