Metal powder post-processing device

Abstract

The utility model discloses a metal powder post-processing device which comprises a screening tank and a powder drying assembly, the screening tank comprises at least two layers of screening assemblies, each screening assembly comprises a powder inlet, a powder outlet, an air inlet and a first screen, and the first screen is located between the powder inlet and the powder outlet; the gas inlet is used for introducing inert gas, and the powder outlet is hermetically connected with the powder drying assembly; the powder drying assembly comprises a sealing shell, at least two layers of powder spreading belts, a heating piece and a dehumidifying piece, and the powder spreading belts are rotationally connected to the inner wall of the sealing shell; the conveying directions of the two adjacent layers of powder spreading belts are opposite; and the heating piece and the dehumidifying piece are fixed on the inner wall of the sealing shell. According to the device disclosed by the utility model, a plurality of screening assemblies capable of independently running are arranged in the screening tank, and the screening tank is hermetically connected with the powder drying assembly, so that the whole-course sealed running of the post-treatment of the metal powder can be realized, and the consumption of inert gas is reduced; and the post-treatment efficiency can be obviously improved, the oxygen increment is reduced, meanwhile, impurity introduction is reduced, and the safety of the powder treatment process is improved.

Description

Technical Field

[0001] The utility model relates to a metal powder post-processing device, belonging to the technical field of additive manufacturing. Background Art

[0002] Metal powder additive manufacturing is a technology that uses metal powder as raw material to construct a three-dimensional entity by sintering and stacking layer by layer. This technology is also called metal 3D printing. Metal powder is the raw material, and only part of the powder is sintered and used during the printing process. For example, in the powder bed laser selective melting forming, the laser beam and the powder sintering and melting process will produce a large amount of spatter (feathered splashing metal droplets, spheroidized particles, oxidized smoke, etc.), large-sized special-shaped powders bonded by multiple particles, etc. These abnormal particles are left in the unsintered powder to form "inclusions". If these unsintered powders are to be recycled and reused, they need to be post-processed.

[0003] Post-processing mainly includes screening and baking steps to remove the aforementioned "inclusions" to prevent "inclusions" from affecting the forming quality of powder bed 3D printed parts. With the development and mass application of metal powder additive manufacturing, the recycling of metal powders has exposed problems such as low post-processing efficiency, oxygen increment, and impurity introduction. At present, metal 3D printing mainly uses powders with a particle size of 15 to 53μm. The post-processing screening is mainly completed using a 150-230 mesh screen sieving machine and a feeding tank; the screened metal powder is subsequently collected and baked in an atmosphere or inert gas oven.

[0004] When screening metal powder, each powder barrel needs to be removed and replaced with a new one after screening, which is inefficient. For example, the average screening efficiency of 15-53μm stainless steel 316L powder used in 3D printing is 2-3kg / min per unit. When baking the screened metal powder, the oven needs to perform a heating step each time metal powder is added, resulting in energy waste. At the same time, post-processing screening and baking are basically carried out in an open environment, which poses the risk of impurity introduction and high oxygen increment. Utility Model Content

[0005] The utility model provides a metal powder post-processing device, which solves the problems in the prior art that the metal powder post-processing efficiency is low and the temperature needs to be repeatedly raised.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a metal powder post-processing device, including a screening tank and a powder baking component, the screening tank includes at least two layers of screening components, the screening component includes a powder inlet, a powder outlet, an air inlet and a first screen, the first screen is located between the powder inlet and the powder outlet; the air inlet is used to introduce inert gas, and the powder outlet is tightly connected to the powder baking component; the powder baking component includes a sealed shell, at least two layers of powder spreading belts, a heating element and a dehumidifying element, the powder spreading belts are rotatably connected to the inner wall of the sealed shell; the conveying directions of the two adjacent layers of the powder spreading belts are opposite; the heating element and the dehumidifying element are fixed to the inner wall of the sealed shell.

[0007] Preferably, the screening component further comprises a powder outlet for unqualified powder, and the unqualified powder outlet is arranged corresponding to the first sieve.

[0008] Preferably, the screening tank further comprises an ultrasonic device, a vibration isolation spring and a base, wherein the ultrasonic device is mounted on the outer wall of the screening tank, the screening assembly is located above the base, and a vibration isolation spring is arranged between the screening assembly and the base. Ultrasonic vibration swing screening can be achieved by arranging an ultrasonic device on the screening tank, and a vibration isolation spring is arranged between the screening assembly and the base, so as to reduce the vibration force generated by the ultrasonic vibrator on the screening tank during operation, thereby protecting the long-term stability of the equipment.

[0009] Preferably, the first sieve is a 150-270 mesh sieve.

[0010] Preferably, a pre-screening powder tank is connected above the powder inlet, and the pre-screening powder tank includes a first closed valve and a second screen. The screen provided in the pre-screening powder tank is mainly used to remove large irregular impurities such as supports and flakes to avoid damage to the screening machine. As a transfer powder tank for 3D printing post-processing, the volume of the pre-screening powder tank can be designed according to demand; and powder can be continuously added through the closed valve during the post-processing process to avoid air breakage, thereby ensuring that there is continuous powder in the pre-screening powder tank, and the post-processing efficiency will not be affected by the addition of powder, so as to achieve sustainable and stable operation.

[0011] Preferably, the powder baking assembly further comprises a visual sensor and a scraper powder spreader, which are fixed on the inner wall of the powder inlet of the sealed housing. The visual sensor is used for real-time feedback of the powder state after screening, and to detect whether the powder is screened clean; the scraper powder spreader is used to scrape the metal powder accumulated on the powder spreading belt flat and spread the powder evenly, so as to ensure uniform heating and dehumidification during the powder baking process.

[0012] Preferably, the dehumidifying element is a dehumidifier, and the heating element is a heating tube.

[0013] Preferably, heating tubes are provided above, below, and on both sides of each layer of the powder spreading belt, so as to facilitate heating uniformity and segmented temperature control.

[0014] Preferably, the heating tube has a length of 0.6 to 1.2 meters and a heating temperature of 20 to 150° C. The heating temperature setting is determined according to the powder baking efficiency and requirements, and a cooling section can be provided for cooling the powder.

[0015] Preferably, the powder outlet of the powder baking assembly is sealed and connected to a powder collecting tank, and a second airtight valve is provided on the powder collecting tank. The powder collecting tank is used for inert gas protection storage of metal powder after post-processing, and its capacity is determined according to the post-processing amount of the powder. Through the airtight valve of the powder collecting tank, the post-processed metal powder in the powder collecting tank can be directly used, or the powder can be transported in a closed manner, or it can be connected to the material path system of the 3D printing equipment to realize the closed circulation of the powder.

[0016] The device of the utility model can realize the full-process closed operation of metal powder post-processing by arranging multiple independently operable screening components in the screening tank and sealingly connecting the screening tank and the powder baking component, thereby reducing the consumption of inert gas; and can significantly improve the post-processing efficiency, reduce the oxygen increment and at the same time reduce the introduction of impurities, and improve the safety of the powder processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a metal powder post-processing device provided by the utility model;

[0018] Figure 2 It is a cross-sectional view of the powder baking component in the utility model.

[0019] Among them: 1-screening tank, 101-first powder inlet, 102-second powder inlet, 103-first screen, 104-powder outlet A, 105-powder outlet B, 106-powder outlet C, 107-powder outlet D, 108-air inlet A, 109-air inlet B, 2-pre-screening powder tank, 201-first closed valve, 202-second screen, 3-drying powder assembly, 301-sealed shell, 302-rotating shaft, 303-powder spreading belt, 3031-horizontal part, 3032-upward part, 4-powder collecting tank, 401-second closed valve, 5-visual sensor, 6-scraper powder spreader, 7-dehumidifier, 8-heating tube. DETAILED DESCRIPTION

[0020] In order to better understand the essence of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings.

[0021] The utility model is suitable for 3D printing metal powder post-processing, and specifically relates to a metal powder post-processing device, such as Figure 1 and Figure 2As shown, it includes a screening tank 1 and a powder baking component 3, the screening tank 1 includes at least two layers of screening components, the screening component includes a powder inlet, a powder outlet, an air inlet and a first screen 103, the first screen 103 is located between the powder inlet and the powder outlet; the air inlet is used to pass inert gas; the powder outlet is connected to the powder baking component 3; the powder baking component 3 includes a sealed shell 301, at least two layers of powder spreading belts 303, a heating element and a dehumidifying element, the powder spreading belt 303 is rotatably connected to the inner wall of the sealed shell 301; the conveying directions of the two adjacent layers of the powder spreading belts 303 are opposite; the heating element is fixed to the inner wall of the sealed shell 301. The number of screening components is optional and can be determined specifically according to the required screening efficiency. Since each layer of the screening component completes the powder feeding independently, the screening efficiency increases exponentially according to the increase in the number of layers, thereby effectively improving the screening efficiency. The length, number of layers, width and running speed of the powder spreading belt are determined according to the powder baking efficiency, time, requirements and equipment site; whether the powder baking component is equipped with a cooling section is determined according to the powder usage requirements.

[0022] In some embodiments of the present invention, the screening component further includes a powder outlet for unqualified powder, and the unqualified powder outlet is arranged corresponding to the first sieve 103 .

[0023] In some embodiments of the utility model, the screening tank 1 further includes an ultrasonic device, a vibration isolation spring and a base, wherein the ultrasonic device is mounted on the outer wall of the screening tank 1, the screening assembly is located above the base, and a vibration isolation spring is disposed between the screening assembly and the base. Ultrasonic vibration swing screening can be achieved by arranging an ultrasonic device on the screening tank, and a vibration isolation spring is disposed between the screening assembly and the base, thereby reducing the vibration force generated by the ultrasonic vibrator on the screening tank during operation, and protecting the long-term stability of the equipment.

[0024] In some embodiments of the present invention, the first sieve 103 is preferably a 150-270 mesh sieve, which can be selected according to the characteristics of the sieved metal powder and the detected particle size distribution.

[0025] In some embodiments of the utility model, a pre-screening powder tank 2 is connected above the powder inlet, and the pre-screening powder tank 2 includes a first closed valve 201 and a second screen 202. The screen provided in the pre-screening powder tank is mainly used to remove large irregular impurities such as supports and flakes to avoid damage to the screening machine. As a transfer powder tank for post-processing of the 3D printing powder collecting tank, the pre-screening powder tank can be designed with the required volume of powder according to demand; and powder can be continuously added through the closed valve during post-processing to avoid air breakage, thereby ensuring that the pre-screening powder tank is continuously filled with powder, and the post-processing efficiency will not be affected by the addition of powder, so as to achieve sustainable and stable operation.

[0026] In some embodiments of the utility model, the powder baking component 3 further includes a visual sensor 5 and a scraper powder spreader 6, which are fixed on the inner wall of the powder inlet of the sealed housing 301; the visual sensor 5 is used for real-time feedback of the powder state after screening, and to detect whether the powder is screened clean; the scraper powder spreader 6 is used to scrape the metal powder accumulated on the powder spreading belt 303 and spread the powder evenly, so as to ensure uniform heating and dehumidification during the powder baking process. In the actual processing process, a scraper powder spreader 6 can be set on each layer of the powder spreading belt 303 as needed.

[0027] In some embodiments of the present invention, the dehumidifying element is a dehumidifier 7, and the dehumidifier 7 is fixed to the side wall where the powder outlet of the sealed housing 301 is located. The inert gas in the sealed housing can bring water vapor to the dehumidifier.

[0028] In some embodiments of the utility model, the heating element is a heating tube 8, and the heating tube 8 is fixed inside the sealed shell 301. As a preferred embodiment of the utility model, heating tubes 8 are arranged above, below, and on both sides of the powder spreading belt 303, which is conducive to heating uniformity and segmented temperature control. The heating tube 8 is 0.6 to 1.2 meters long and is used for accurate and segmented temperature control of the powder drying machine. The heating capacity is 20 to 150°C, and the heating temperature setting is determined according to the powder drying efficiency and requirements. By setting up multiple sections of heating tubes, segmented temperature control can be achieved, and a cooling section can be set to cool the powder.

[0029] In some embodiments of the utility model, the powder outlet of the powder baking assembly 3 is sealed and connected to the powder collecting tank 4, and the powder collecting tank 4 is provided with a second closed valve 401. The powder collecting tank is used for the inert gas protection storage of the metal powder after post-processing, and its capacity is determined according to the post-processing amount of the powder. Through the closed valve of the powder collecting tank, the metal powder after post-processing in the powder collecting tank can be directly used, or the powder can be transported in a closed manner, and it can also be connected to the material path system of the 3D printing equipment to realize the closed circulation of the powder.

[0030] Example 1

[0031] Taking 3D printing of stainless steel 316L metal powder as an example, a certain 3D printing production line equipment runs 7*24h, with a daily post-processing volume of stainless steel 316L metal powder of 12 tons, and the capacity of the 3D printing powder collection tank is 100kg. The device operates under argon circulation protection.

[0032] In this embodiment, the configuration of the equipment is as follows:

[0033] 1. The capacity of the pre-screening powder tank 2 is set to 1000kg, and a second screen 202 of 60 mesh is configured. During the post-processing process, powder can be continuously added through the first closed valve 201 to ensure that the pre-screening powder tank 2 is continuously filled with powder, and the post-processing efficiency will not be affected by the addition of powder, so that sustainable and stable work can be achieved.

[0034] 2. The screening tank 1 is equipped with two layers of screening components, ultrasonic devices, vibration isolation springs and bases, specifically: the first screening component includes the first powder inlet 101, the first screen 103, the powder outlet A104, the powder outlet C106 and the air inlet A108; the second screening component includes the second powder inlet 102, the first screen 103, the powder outlet B105, the powder outlet D107 and the air inlet 109B; the powder outlet C106 and the powder outlet D107 are the outlets for unqualified powder. Among them, the first screen 103 uses 200 mesh, and the screening efficiency of each layer of the screen reaches 5kg / min. The total screening efficiency of the screening structure of the metal powder closed cycle post-processing device reaches 600kg / h.

[0035] 3. The powder baking component 3 is provided with three layers of powder spreading belts 303 , a dehumidifier 7 and a heating tube 8 , and a visual sensor 5 and a scraper powder spreading device 6 are arranged above the powder spreading belt 303 on the top layer.

[0036] The width of the powder spreading belt 303 is 100 cm, the length of each layer is 250 cm, and the running speed is 25 cm / min.

[0037] According to the baking conditions of stainless steel 316L metal powder (temperature 105°C without cooling, baking time 30 minutes), heating tubes 8 with a length of 1.2 meters are selected and evenly distributed around the powder spreading belt 303, specifically: a layer of heating tubes 8 is set at the top and bottom of the sealed shell 301; two layers of heating tubes 8 are set between two adjacent layers of powder spreading belts 303; each layer of heating tubes 8 is provided with two, respectively located on both sides of the same powder spreading belt 303. The powder spreading thickness of the scraper powder spreading device 6 is 1 cm.

[0038] 4. A powder collecting tank 4 with a capacity of 2000 kg is configured, and a second closed valve 401 is provided at the powder outlet of the powder collecting tank 4 .

[0039] The working process of the utility model device:

[0040] 1. The 316L powder to be processed flows into the pre-screening powder tank 2 from the powder collecting part of the 3D printer, and after being screened by the second sieve 202 with a mesh size of 60, enters the first sieve 103 corresponding to each other through the first powder inlet 101 and the second powder inlet 102 respectively, and enters the sealed housing 301 through the powder outlet A104 and the powder outlet B105 after screening.

[0041] 2. The sieved metal powder is spread by a scraper powder spreader 6 to a thickness of 1 cm, the visual sensor 5 provides real-time feedback on the powder state, and the dehumidifier 7 removes the water vapor generated by the baking powder.

[0042] 3. After the powder baking is completed, the metal powder flows into the powder collecting tank 4 and can be used directly or recycled, or transported in a closed manner.

[0043] It should be noted that although the utility model is described through the above embodiments, the utility model can also have other various embodiments. Without departing from the spirit and scope of the utility model, it is obvious that those skilled in the art can make various corresponding changes and deformations to the utility model, but these changes and deformations should fall within the scope of protection of the attached claims of the utility model and their equivalents.

Claims

1. A metal powder post-processing device, characterized in that: The invention comprises a screening tank (1) and a powder baking component (3), wherein the screening tank (1) comprises at least two layers of screening components, wherein the screening component comprises a powder inlet, a powder outlet, an air inlet and a first screen (103), wherein the first screen (103) is located between the powder inlet and the powder outlet; the air inlet is used to introduce inert gas, and the powder outlet is airtightly connected to the powder baking component (3); the powder baking component (3) comprises a sealed shell (301), at least two layers of powder spreading belts (303), a heating element and a dehumidifying element, wherein the powder spreading belts (303) are rotatably connected to the inner wall of the sealed shell (301); the conveying directions of two adjacent layers of the powder spreading belts (303) are opposite; and the heating element and the dehumidifying element are fixed to the inner wall of the sealed shell (301).

2. The metal powder post-processing device according to claim 1, characterized in that: The screening component further comprises an unqualified powder outlet, wherein the unqualified powder outlet is arranged corresponding to the first screen (103).

3. The metal powder post-processing device according to claim 1, characterized in that: The screening tank (1) further comprises an ultrasonic device, a vibration isolation spring and a base; the ultrasonic device is mounted on the outer wall of the screening tank (1); the screening component is located above the base; and a vibration isolation spring is provided between the screening component and the base.

4. The metal powder post-processing device according to claim 1, characterized in that: The first sieve (103) is a sieve with a mesh size of 150 to 270.

5. The metal powder post-processing device according to claim 1, characterized in that: A pre-screening powder tank (2) is connected above the powder inlet, and the pre-screening powder tank (2) comprises a first airtight valve (201) and a second screen (202).

6. The metal powder post-processing device according to claim 1, characterized in that: The powder baking component (3) further comprises a visual sensor (5) and a scraper powder spreader (6), wherein the visual sensor (5) and the scraper powder spreader (6) are fixed on the inner wall of the powder inlet of the sealed housing (301).

7. The metal powder post-processing device according to claim 1, characterized in that: The dehumidifying element is a dehumidifier (7), and the heating element is a heating tube (8).

8. The metal powder post-processing device according to claim 7, characterized in that: Heating pipes (8) are arranged above, below, and on both sides of each layer of the powder spreading belt (303).

9. The metal powder post-processing device according to claim 7, characterized in that: The heating tube (8) has a length of 0.6 to 1.2 meters and a heating temperature of 20 to 150°C.

10. The metal powder post-processing device according to claim 1, characterized in that: The powder outlet of the powder baking component (3) is sealedly connected to the powder collecting tank (4), and the powder collecting tank (4) is provided with a second airtight valve (401).

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