Apparatus and method for precise delivery, spreading and containment of metal powder under microgravity

Abstract

The application discloses a kind of accurate transport, spreading and restraint device and method of metal powder under microgravity, and relates to the technical field of space additive manufacturing.The specific includes: powder transport device, metal powder is adsorbed using negative pressure adsorption force and is quantitatively controlled after conveying by quantitative mechanism;Powder spreading device, including rotatable electrostatic carrier, metal powder is transferred and deposited on forming substrate under the action of electric field, and the device also includes densification excitation mechanism, and vibration or impact excitation is generated during deposition process to make powder rearrangement densification;And powder restraint device, generates restraint electric field in forming substrate boundary area to inhibit powder disorder diffusion.The purpose is to solve the problem that metal powder is easy to suspend, difficult to form uniform and dense powder layer and difficult to keep boundary under microgravity environment.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology under microgravity conditions, and particularly to devices and methods for the precise transport, spreading and constraining of metal powder under microgravity. Background Technology

[0002] Metal powder bed melting technology is considered an important approach to achieving on-orbit manufacturing in space due to its high material utilization rate and ability to directly manufacture metal components with complex topologies. However, existing ground-based metal powder bed melting equipment relies heavily on gravity for its core powder feeding, spreading, and bed maintenance mechanisms. In a ground environment, powder falls under its own weight and is leveled by mechanical scrapers; the stability of the powder bed is maintained by the normal pressure provided by gravity and the frictional force between particles.

[0003] In a microgravity environment, metal powders are prone to suspension and drift, making it impossible to form a continuous and uniform powder layer using traditional mechanical extrusion methods. Furthermore, the disordered diffusion of powder can contaminate optical systems and motion mechanisms, causing equipment malfunctions. In addition, due to the lack of natural settling and compaction caused by gravity, the powder layer under microgravity has high porosity and low bulk density, severely affecting the quality of melt forming. Existing airflow or simple vibration-assisted methods are insufficient to achieve precise powder transport while ensuring high-density spreading and effective boundary constraints.

[0004] Therefore, how to achieve stable quantitative transport of metal powder, high density and uniform spreading, and effective constraint of powder bed boundaries under microgravity environment has become an urgent technical problem to be solved. Summary of the Invention

[0005] The main objective of this invention is to provide a device and method for the precise transport, spreading and constraint of metal powder under microgravity, aiming to achieve stable quantitative transport, high-density uniform spreading and effective constraint of powder bed boundaries of metal powder under microgravity environment.

[0006] To achieve the above objectives, this invention proposes a device for the precise transport, spreading, and constraint of metal powder under microgravity, comprising: The powder conveying device is constructed by using negative pressure adsorption force to adsorb metal powder, and using a quantitative mechanism to quantitatively control the adsorbed metal powder before conveying it along a predetermined path. A powder spreading apparatus comprising a rotatable electrostatic carrier configured to receive metal powder from the powder transport device and transfer and deposit the metal powder onto a shaped substrate under the action of an electric field; The device further includes a densification excitation mechanism, which is configured to generate vibration or impact excitation during the metal powder transfer and deposition process, so that the metal powder deposited on the shaped substrate undergoes rearrangement and densification. And a powder confinement device, comprising an electric field generating unit disposed at the periphery of the molded substrate, the electric field generating unit being configured to generate a confinement electric field in the boundary region of the molded substrate to suppress the disordered diffusion of metal powder under microgravity conditions.

[0007] Preferably, the powder conveying device includes a powder-absorbing roller, a negative pressure generator, and a powder-absorbing pipe; the surface of the powder-absorbing roller is provided with micro-nano air channels, the powder-absorbing roller is connected to the negative pressure generator through the powder-absorbing pipe, and the negative pressure generator is configured to generate the negative pressure adsorption force through the micro-nano air channels.

[0008] Preferably, the metering mechanism includes a lower scraper disposed between the powder-absorbing roller and the powder spreading device, the lower scraper being configured to correct the metal powder adsorbed on the surface of the powder-absorbing roller to a preset thickness; the powder conveying device further includes an upper scraper disposed on the return side of the powder-absorbing roller, the upper scraper being configured to clean the residual metal powder on the surface of the powder-absorbing roller.

[0009] Preferably, the electrostatic carrier is a toner cartridge; the powder spreading device further includes a charging roller, which is configured to contact the surface of the toner cartridge or be disposed within the discharge gap distance of the toner cartridge surface to charge the surface of the toner cartridge, causing the metal powder to be adsorbed on the surface of the toner cartridge; the forming substrate carries a charge with a polarity opposite to that of the toner cartridge and an absolute potential value higher than that of the surface potential of the toner cartridge, i.e., satisfying the requirement of... To form the electric field.

[0010] Preferably, the charging roller integrates a voltage regulation module, which is configured to adjust the charging voltage according to the dielectric constant or conductivity of the metal powder.

[0011] Preferably, the densification excitation mechanism includes a centrifugal hammer disposed inside the selenium drum, the centrifugal hammer being configured to generate periodic shock waves or vibration excitation as the selenium drum rotates.

[0012] Preferably, the electric field generating unit includes a charge emitter or an electrode array, wherein the charge emitter or the electrode array is configured to apply a charge with opposite polarity to the selenium drum to the forming substrate, or to form an electrostatic force pointing inward toward the forming substrate at the boundary of the forming substrate.

[0013] Preferably, it also includes a negative pressure powder suction device and a powder collector, wherein the negative pressure powder suction device is configured to provide adsorption negative pressure for the powder collector, so as to directionally adsorb and collect the metal powder suspended in a microgravity environment.

[0014] Preferably, the powder collector has powder collection holes distributed on it, and the negative pressure powder suction device includes a powder recovery suction pipe and a negative pressure recovery generator connected to the powder collector.

[0015] Preferably, it further includes a powder spreading hopper, a motion slide rail, a lifting platform, a laser, and a powder chamber; the powder conveying device and the powder spreading device are disposed in the powder spreading hopper, and the powder spreading hopper is slidably disposed on the motion slide rail; the forming substrate is disposed on the lifting platform; the laser is disposed above the forming substrate; the powder chamber is used to supply the metal powder to the powder conveying device.

[0016] This application also discloses a microgravity metal powder bed melting, transporting, spreading, and confining method using the apparatus described in any of the preceding claims. The method includes the following steps: using the negative pressure adsorption force and metering mechanism of the powder transport device to quantitatively adsorb and transport metal powder to the powder spreading device; using the electrostatic carrier of the powder spreading device to adsorb the metal powder, and transferring and depositing the metal powder onto a forming substrate under the action of an electric field; during the metal powder transfer and deposition process, using a densification excitation mechanism to generate vibration or impact excitation, causing the metal powder deposited on the forming substrate to undergo rearrangement and densification; and using a powder confining device to generate a confining electric field in the boundary region of the forming substrate to suppress the disordered diffusion of metal powder in a microgravity environment.

[0017] Preferably, the step of using the electrostatic carrier of the powder spreading device to adsorb the metal powder includes: charging the selenium drum, which serves as the electrostatic carrier, using a charging roller, and adjusting the charging voltage and polarity according to the dielectric constant or conductivity of the metal powder.

[0018] Preferably, the step of generating vibration or impact excitation using a densification excitation mechanism includes: using a centrifugal hammer disposed inside the electrostatic carrier to generate periodic shock waves as the electrostatic carrier rotates.

[0019] Preferably, the method further includes: using a negative pressure powder suction device and a powder collector to perform directional adsorption and recovery of the metal powder suspended outside the forming area or under microgravity conditions.

[0020] This invention proposes a device for the precise transport, spreading, and constraint of metal powder under microgravity. By utilizing negative pressure adsorption and a quantitative mechanism, the powder transport device overcomes the challenge of powder not flowing under gravity in a microgravity environment, achieving forced adsorption and quantitative delivery of the powder. Using a powder spreading device incorporating an electrostatic carrier, metal powder is precisely transferred and deposited onto a forming substrate under the influence of an electric field. Furthermore, the vibration or impact excitation generated during the deposition process by a densification excitation mechanism forces the powder particles to rearrange and densify in the microgravity environment, significantly improving the packing density and uniformity of the powder bed. Simultaneously, a powder constraint device positioned around the periphery of the forming substrate generates a constraint electric field, effectively suppressing the disordered diffusion of metal powder under microgravity, ensuring the cleanliness and boundary stability of the forming area, thus providing a reliable device foundation for high-precision metal additive manufacturing in space environments. Attached Figure Description

[0021] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a schematic diagram of the overall structure of the device for precise transport, spreading and constraining of metal powder under microgravity provided in an embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the internal structure of the powder conveying device and the powder spreading device provided in the embodiments of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the powder suction roller provided in an embodiment of the present invention.

[0024] Figure 4 This is a schematic diagram of the electrostatic carrier and densification excitation mechanism provided in an embodiment of the present invention.

[0025] Figure 5 This is a schematic diagram of the structure of a powder collector provided in an embodiment of the present invention.

[0026] Figure 6 This is a schematic diagram of the powder confinement device and the forming substrate provided in an embodiment of the present invention.

[0027] 1. Powder spreading hopper; 1.1. Powder suction roller; 1.1.1. Micro-nano air channels; 1.2. Charging roller; 1.3. Electrostatic carrier; 1.3.1. Densification excitation mechanism; 1.4. Lower scraper; 1.5. Upper scraper; 1.6. Negative pressure generator; 1.7. Powder suction pipe; 1.8. Powder chamber; 2. Motion slide rail; 3. Hydraulic lifting platform; 3.1. Forming substrate; 3.2. Electric field generating unit; 4. Laser; 5. Powder collector; 5.1. Powder collection hole; 6. Metal powder; 8. Negative pressure powder suction device. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort should fall within the scope of protection of the present application.

[0029] Example 1 like Figures 1 to 6 As shown, this embodiment provides a device for the precise transport, spreading, and constraint of metal powder under microgravity. This device is specifically designed for use in microgravity or weak gravity environments, aiming to solve the problem of traditional gravity-based powder spreading mechanisms failing under weightless conditions, particularly addressing the technical challenges of metal powder's easy suspension and diffusion, difficulty in forming a uniform and dense powder layer, and difficulty in maintaining powder bed boundaries. The device mainly consists of a powder transport device, a powder spreading device, a powder constraint device, a densification excitation mechanism, and an auxiliary powder recovery system.

[0030] Please refer to this carefully. Figure 1 and Figure 2 The device comprises a powder spreading chamber 1, a motion guide rail 2, a hydraulic lifting platform 3, a laser 4, a powder collector 5, and a powder chamber 1.8. The powder spreading chamber 1, as the core operating unit, integrates a powder conveying device and a powder spreading device, and is slidably mounted on the motion guide rail 2. The motion guide rail 2 is a high-precision linear guide rail that drives the powder spreading chamber 1 to reciprocate above the forming area to complete the layer-by-layer powder spreading operation. The forming substrate 3.1 is mounted on the hydraulic lifting platform 3, which can perform micron-level precision lifting movements along the Z-axis to control the layer thickness of each printed layer. The laser 4 is positioned above the forming substrate 3.1 and is used to selectively melt the spread metal powder 6 based on the slicing data. The powder chamber 1.8 serves as a raw material storage unit, continuously supplying metal powder 6 to the powder conveying device.

[0031] In the specific powder transport logic, this embodiment abandons the traditional gravity powder falling mode and instead adopts a forced negative pressure adsorption transport scheme. For example... Figure 2 and Figure 3As shown, the powder conveying device specifically includes a powder-collecting roller 1.1, a negative pressure generator 1.6, a powder-collecting pipe 1.7, and a metering mechanism. The powder-collecting roller 1.1 is the core component for powder gripping, and its surface is precision-machined with micro / nano pores 1.1.1. The pore size of these micro / nano pores 1.1.1 must be smaller than the minimum particle size of the metal powder 6. For example, when using metal powder with a particle size range of 15μm to 53μm, the pore size of the micro / nano pores 1.1.1 is preferably set to 5μm to 10μm to ensure that only gas passes through while powder is intercepted. The powder-collecting roller 1.1 has a hollow internal structure and is connected to the powder-collecting pipe 1.7 via a rotary sealing joint, which in turn connects to the negative pressure generator 1.6. The negative pressure generator 1.6 is configured to establish a stable negative pressure environment within the cavity of the powder-collecting roller 1.1 through the powder-collecting pipe 1.7, thereby generating a strong aerodynamic adsorption force at the micro / nano pores 1.1.1. This design allows the metal powder 6 to be firmly adsorbed onto the surface of the powder-absorbing roller 1.1 even in a microgravity environment, forming a powder layer that rotates with the roller.

[0032] To ensure the accuracy of powder delivery, a metering mechanism is integrated into the transport path. Specifically, the metering mechanism includes a lower scraper 1.4 positioned between the powder-absorbing roller 1.1 and the powder spreading device. A preset gap is maintained between the lower scraper 1.4 and the surface of the powder-absorbing roller 1.1, which determines the powder throughput entering the subsequent spreading stage. The lower scraper 1.4 is designed to trim the initial irregular powder layer adsorbed on the surface of the powder-absorbing roller 1.1 into a uniform powder layer of a preset thickness, ensuring the metering accuracy of powder delivery. In addition, the powder transport device also includes an upper scraper 1.5 positioned on the return side of the powder-absorbing roller 1.1. The upper scraper 1.5 is close to or very close to the surface of the powder-absorbing roller 1.1, designed to clean any residual metal powder on the surface of the powder-absorbing roller 1.1 after delivery, preventing blockage of the micro / nano pores 1.1.1 and maintaining the adsorption efficiency of the roller surface.

[0033] After the quantitative transport of powder is completed, the powder enters the spreading stage. This embodiment of the powder spreading device innovatively employs electrostatic transfer technology. For example... Figure 2As shown, the powder spreading device includes a rotatable electrostatic carrier 1.3 and a charging roller 1.2 used in conjunction with it. In this embodiment, the electrostatic carrier 1.3 is preferably a toner cartridge coated with a photoconductive or dielectric material, and the surface of the toner cartridge is treated with a wear-resistant coating and has anti-contamination properties to avoid adverse reactions between the metal powder and the toner cartridge material or the introduction of impurities. The charging roller 1.2 is configured to contact the surface of the toner cartridge or be positioned within the discharge gap distance on the surface of the toner cartridge, for example, at a distance of 50 μm to 200 μm. The charging roller 1.2 is used to uniformly charge the surface of the toner cartridge, giving it a specific electrostatic potential. The charging roller 1.2 integrates a high-precision voltage regulation module, which can intelligently adjust the amplitude and polarity of the charging voltage according to the physical properties of the metal powder 6, namely the dielectric constant or conductivity. This device can be adapted to different types of metal powders, such as titanium alloys, aluminum alloys, stainless steel, nickel-based alloys, etc. The applied voltage parameters will differ significantly between aluminum alloy powder with good conductivity and ceramic-reinforced metal powder with poor conductivity, in order to ensure the best adsorption effect.

[0034] When the charged drum surface rotates to the area in contact with or near the powder suction roller 1.1, due to electrostatic attraction, the metal powder 6, after being trimmed by the lower scraper 1.4, is transferred from the powder suction roller 1.1 surface and adsorbed onto the drum surface. Subsequently, the drum carrying the powder rotates above the forming substrate 3.1. To achieve smooth powder transfer from the drum to the substrate, this embodiment constructs a special electric field environment. The forming substrate 3.1 is applied with a charge of opposite polarity to the drum and with an absolute potential value higher than that of the drum surface, satisfying the potential relationship formula. .in, The potential of the substrate 3.1 is given. The potential difference is the electric potential of the drum surface. This potential difference creates a strongly directional electric field between the drum and the substrate, driving the metal powder 6 to overcome van der Waals forces and other adhesion forces, detach from the drum surface, and be precisely deposited onto the molding substrate 3.1.

[0035] To address the issues of loose powder deposition and lack of natural gravity-induced densification mechanisms under microgravity conditions, this device also integrates a densification excitation mechanism 1.3.1. For example... Figure 4As shown, the densification excitation mechanism 1.3.1 is cleverly positioned within the internal cavity of the electrostatic carrier 1.3, i.e., the drum. Specifically, the densification excitation mechanism 1.3.1 includes a centrifugal hammer structure, which is designed to generate periodic shock waves or high-frequency vibrations as the drum rotates. During the transfer and deposition of metal powder 6 from the drum onto the forming substrate 3.1, this internally transmitted mechanical vibration is transmitted to the deposited powder particles, forcing them to overcome static friction and fill the gaps, thus achieving rearrangement and densification. By adjusting the rotational speed of the drum 1.3, the eccentricity of the centrifugal hammer 1.3.1, and the impact frequency, the impact energy can be precisely controlled to adapt to the densification requirements of powders with different particle size distributions and flowability.

[0036] Furthermore, to address the issue of powder easily and disorderly diffusing outside the forming area under microgravity conditions, this device is equipped with a powder confinement device. For example... Figure 5 and Figure 6 As shown, the powder confinement device includes an electric field generating unit 3.2 disposed around the periphery of the forming substrate 3.1. The electric field generating unit 3.2 can specifically be a charge emitter or a microelectrode array arranged around the substrate. The electric field generating unit 3.2 is configured to generate an invisible confinement electric field, i.e., a virtual electric wall, in the physical boundary region of the forming substrate 3.1. This electric field generating unit 3.2 applies a charge with opposite polarity to the toner cartridge to the forming substrate 3.1, or forms an electrostatic field pointing inwards towards the forming substrate 3.1 at the boundary. When the metal powder 6 at the edge attempts to drift outwards, it is constrained by the repulsive or attractive force of this electrostatic field pointing towards the center, thus being confined within a preset forming range, effectively suppressing the risk of powder contamination under microgravity conditions.

[0037] To further enhance system reliability and environmental cleanliness, this device also includes a negative pressure powder suction device 8 and a powder collector 5. The powder collector 5 is preferably a long strip structure, arranged along the movement path of the powder spreading chamber 1 or integrated into the powder spreading chamber 1, with several powder collection holes 5.1 distributed on its surface. The negative pressure powder suction device 8 includes a recovery negative pressure generator and a recovery powder suction pipe, which is connected to the powder collector 5. The negative pressure powder suction device 8 is configured to provide a continuous negative pressure for the powder collector 5, directionally adsorbing and collecting trace amounts of airborne metal powder 6 floating outside the forming area or generated during the powder spreading process. The collected powder can undergo gas-solid separation through filtration components such as a cyclone separator and is then returned to the powder chamber 1.8 for reuse, achieving closed-loop powder management.

[0038] In summary, the method for melting, transporting, spreading, and constraining a microgravity metal powder bed using the aforementioned device includes the following key steps: First, environmental preparation is performed by establishing an inert atmosphere or vacuum environment according to process requirements, and setting the target negative pressure of the negative pressure generator 1.6, the charging voltage and polarity of the charging roller 1.2, and the electric field strength of the electric field generating unit 3.2. Second, the metal powder 6 is grasped from the powder chamber 1.8 using the negative pressure adsorption force generated by the powder suction roller 1.1 of the powder transport device in conjunction with the micro-nano pores 1.1.1, and quantitative control and layer thickness adjustment of the adsorbed metal powder 6 are achieved through the mechanical scraping action of the lower scraper 1.4, followed by transport to the transfer area along a predetermined path. Next, the charging roller 1.2 of the powder spreading device is used to charge the selenium drum, which serves as the electrostatic carrier 1.3. The charging parameters are adjusted according to the dielectric constant or conductivity of the metal powder 6, so that the surface of the selenium drum adsorbs the metal powder 6 from the powder suction roller 1.1. Then, under the action of an electric field, especially based on... Driven by the potential difference, metal powder 6 is transferred and deposited onto the forming substrate 3.1. During this transfer deposition process, vibration or impact excitation generated by the densification excitation mechanism 1.3.1 built into the selenium drum causes the metal powder deposited on the forming substrate 3.1 to undergo in-situ rearrangement and densification, increasing the packing density of the powder bed. Simultaneously, the electric field generating unit 3.2 of the powder confinement device generates a confinement electric field in the boundary region of the forming substrate 3.1, suppressing the disordered diffusion of metal powder 6 under microgravity conditions throughout the process. Finally, for any trace amounts of escaped powder, the negative pressure powder suction device 8 and the powder collector 5 are used for directional adsorption and recovery, ensuring the safety of the cabin environment.

[0039] Example 2 This embodiment, based on Embodiment 1, further improves and expands the device for precise transport, spreading, and constraint of metal powder under microgravity, aiming to overcome the limitations of single-material printing and provide adaptive transport and spreading schemes for metal powders with different physical properties. Figure 1 As shown, in this embodiment, the powder conveying device and powder spreading device are configured as multiple independent systems. For example, two identical conveying and spreading components are symmetrically arranged on both sides of the powder spreading chamber 1. Each system is connected to an independent powder chamber 1.8, thereby enabling composite printing or layer-switching printing of multiple metal materials.

[0040] In multi-material printing scenarios, different types of metal powders, such as titanium alloy powder and aluminum alloy powder, have significantly different physical properties, especially in terms of dielectric constant and conductivity. Using constant electrostatic parameters makes it difficult to guarantee optimal adsorption density and spreading uniformity for two such disparate powders. Therefore, this embodiment fully utilizes the voltage regulation module integrated within the charging roller 1.2. When transporting the first type of metal powder, the voltage regulation module outputs a first preset voltage based on the high dielectric constant of that powder, ensuring sufficient charge density on the surface of the drum (specifically the electrostatic carrier 1.3) to adsorb the powder. When switching to the second type of metal powder, the voltage regulation module automatically adjusts to a second preset voltage to match the conductivity of the second powder, preventing powder splashing due to charge overload or adsorption gaps due to insufficient charge. This material-adaptive voltage regulation mechanism ensures high-quality electrostatic transfer for both highly reactive titanium alloys and low-density aluminum alloys under microgravity conditions.

[0041] Furthermore, preventing cross-contamination during material switching is crucial for ensuring the metallurgical quality of the formed parts. This embodiment utilizes the synergistic effect of the upper scraper 1.5 and the negative pressure powder suction device 8 to achieve this goal. When switching from the first material to the second material, the powder conveying device stops sucking powder from the powder chamber 1.8, while the powder suction roller 1.1 continues to idle, using the upper scraper 1.5 to thoroughly scrape away any residual powder on the surface. Simultaneously, the negative pressure powder suction device 8 increases its suction power, forcefully removing suspended particles from the powder-coating chamber 1 through the powder collector 5. At this time, the electric field generating unit 3.2 of the powder confinement device can temporarily reverse the electric field polarity or enhance the boundary potential barrier, repelling the foreign powder remaining in the non-forming area of ​​the forming substrate 3.1 to the vicinity of the powder collection hole 5.1, where it is carried away by the negative pressure airflow. After this cleaning cycle, the second conveying system is activated to transport the second type of metal powder. This design not only enables flexible switching between multiple materials but also actively creates clean switching conditions in a microgravity environment lacking natural sedimentation purification.

[0042] Example 3 This embodiment focuses on describing the specific process of microgravity metal powder bed melting using the above-mentioned device, particularly the dynamic control method for powder densification and confinement. This method first involves environmental setup and precise powder quantification and adsorption. In the startup phase, a sealed space is first established and filled with inert gas or evacuated. Then, a negative pressure generator 1.6 establishes an adsorption negative pressure at the micro-nano pores 1.1.1 of the powder suction roller 1.1 through the powder suction pipe 1.7. The pore size of these micro-nano pores 1.1.1 is strictly controlled between 5 μm and 10 μm to intercept metal powder 6 with a particle size greater than 15 μm. As the powder suction roller 1.1 rotates, the metal powder is forcibly adsorbed and carried into the quantification zone. At this time, the lower scraper 1.4 trims the powder layer into a uniform thin layer, for example, 50 μm thick, ensuring a constant amount of powder entering the transfer stage.

[0043] The electrostatic transfer and densification stages then commence. Charging roller 1.2 charges the drum surface, imparting a potential of, for example, -1000V. A powder-collecting roller 1.1, carrying a measured amount of powder, contacts or passes close to the drum, transferring the powder to its surface under electrostatic attraction. As the drum rotates above the forming substrate 3.1, the system applies a voltage of, for example, +1500V or higher absolute value to the forming substrate 3.1, creating a conformal... A strong electric field is applied. Metal powder 6 is propelled towards the forming substrate 3.1 by the electric field. During this process, a densification excitation mechanism 1.3.1, specifically a centrifugal hammer, located inside the drum, rotates at, for example, 3000 revolutions per minute, generating high-frequency vibrations that are transmitted to the drum surface. This vibration breaks down the static friction and agglomeration between powder particles, causing the powder to rearrange under microgravity, filling the pores and thus forming a highly dense powder bed on the forming substrate 3.1.

[0044] Finally, there is the boundary constraint and recycling stage. Throughout the powder spreading process, the electric field generating unit 3.2, located around the periphery of the forming substrate 3.1, continuously operates, generating a centripetal electrostatic force pointing inwards from the substrate, acting like an invisible fence to lock the powder within the forming area. For the very few powder particles that escape the boundary or remain suspended, the negative pressure powder suction device 8 sucks them into the recycling channel through the powder collection holes 5.1 distributed on the powder collector 5. The recycled powder is then filtered to remove impurities and returned to the powder chamber 1.8. The laser 4 then melts and welds the dense and clearly defined powder layer. Layer by layer, a complex and high-performance metal component is finally manufactured under microgravity conditions.

[0045] The above description is merely a preferred embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A device for precise transport, spreading, and constraining of metal powder under microgravity, characterized in that, include: The powder conveying device is constructed by using negative pressure adsorption force to adsorb metal powder (6), and using a quantitative mechanism to quantitatively control the adsorbed metal powder (6) before conveying it along a predetermined path. A powder spreading apparatus comprising a rotatable electrostatic carrier (1.3) configured to receive metal powder (6) from the powder transport apparatus and transfer the metal powder (6) onto a forming substrate (3.1) under the action of an electric field; The device further includes a densification excitation mechanism (1.3.1), which is configured to generate vibration or impact excitation during the transfer and deposition of the metal powder (6), so that the metal powder deposited on the shaped substrate (3.1) undergoes rearrangement and densification. And a powder confinement device comprising an electric field generating unit (3.2) disposed on the periphery of the shaped substrate (3.1), the electric field generating unit (3.2) being configured to generate a confinement electric field in the boundary region of the shaped substrate (3.1) to suppress the disordered diffusion of metal powder (6) in a microgravity environment.

2. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 1, characterized in that, The powder conveying device includes a powder-absorbing roller (1.1), a negative pressure generator (1.6), and a powder-absorbing pipe (1.7). The surface of the powder-absorbing roller (1.1) is provided with micro-nano air channels (1.1.1). The powder-absorbing roller (1.1) is connected to the negative pressure generator (1.6) through the powder-absorbing pipe (1.7). The negative pressure generator (1.6) is configured to generate the negative pressure adsorption force through the micro-nano air channels (1.1.1).

3. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 2, characterized in that, The quantitative mechanism includes a lower scraper (1.4) disposed between the powder-absorbing roller (1.1) and the powder spreading device. The lower scraper (1.4) is configured to correct the metal powder (6) adsorbed on the surface of the powder-absorbing roller (1.1) to a preset thickness. The powder conveying device also includes an upper scraper (1.5) disposed on the return side of the powder-absorbing roller (1.1). The upper scraper (1.5) is configured to clean the residual metal powder on the surface of the powder-absorbing roller (1.1).

4. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 1, characterized in that, The electrostatic carrier (1.3) is a toner cartridge; the powder spreading device further includes a charging roller (1.2), which is configured to contact the surface of the toner cartridge or be positioned within the discharge gap distance of the surface of the toner cartridge to charge the surface of the toner cartridge, thereby adsorbing the metal powder (6) onto the surface of the toner cartridge; the forming substrate (3.1) carries a charge with a polarity opposite to that of the toner cartridge and an absolute potential value higher than that of the surface potential of the toner cartridge, i.e., satisfying the requirement of... To form the electric field.

5. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 4, characterized in that, The charging roller (1.2) has an integrated voltage regulation module, which is configured to adjust the charging voltage according to the dielectric constant or conductivity of the metal powder (6).

6. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 4, characterized in that, The densification excitation mechanism (1.3.1) includes a centrifugal hammer disposed inside the selenium drum, the centrifugal hammer being configured to generate periodic shock waves or vibration excitation as the selenium drum rotates.

7. The device for precise transport, spreading, and constraint of metal powder under microgravity according to claim 4, characterized in that, The electric field generating unit (3.2) includes a charge emitter or an electrode array configured to apply a charge opposite to the polarity of the selenium drum to the forming substrate (3.1), or to form an electrostatic force pointing inwards from the boundary of the forming substrate (3.1).

8. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 1, characterized in that, It also includes a negative pressure powder suction device (8) and a powder collector (5), wherein the negative pressure powder suction device (8) is configured to provide adsorption negative pressure to the powder collector (5) for directional adsorption and collection of the metal powder (6) suspended in a microgravity environment.

9. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 8, characterized in that, The powder collector (5) has powder collection holes (5.1) distributed on it, and the negative pressure powder suction device (8) includes a recovery powder suction pipe and a recovery negative pressure generator connected to the powder collector (5).

10. The device for precise transport, spreading, and constraining of metal powder under microgravity according to claim 1, characterized in that, It also includes a powder spreading hopper (1), a motion slide rail (2), a lifting platform (3), a laser (4), and a powder chamber (1.8); the powder conveying device and the powder spreading device are disposed in the powder spreading hopper (1), and the powder spreading hopper (1) is slidably disposed on the motion slide rail (2); the forming substrate (3.1) is disposed on the lifting platform (3); the laser (4) is disposed above the forming substrate (3.1); the powder chamber (1.8) is used to supply the metal powder (6) to the powder conveying device.

11. A method for melting, transporting, spreading, and constraining a microgravity metal powder bed, characterized in that, Using the apparatus as described in any one of claims 1 to 10, the method comprises the following steps: using the negative pressure adsorption force and quantitative mechanism of the powder transport device to quantitatively adsorb and transport metal powder (6) to the powder spreading device; using the electrostatic carrier (1.3) of the powder spreading device to adsorb the metal powder (6), and under the action of an electric field to transfer and deposit the metal powder (6) onto the forming substrate (3.1); during the transfer and deposition of the metal powder (6), using the densification excitation mechanism (1.3.1) to generate vibration or impact excitation, so that the metal powder deposited on the forming substrate (3.1) undergoes rearrangement and densification; and using the powder confinement device to generate a confinement electric field in the boundary region of the forming substrate (3.1) to suppress the disordered diffusion of the metal powder (6) under microgravity.

12. The method according to claim 11, characterized in that, The step of using the electrostatic carrier (1.3) of the powder spreading device to adsorb the metal powder (6) includes: charging the selenium drum, which serves as the electrostatic carrier (1.3), with the charging roller (1.2), and adjusting the charging voltage and polarity according to the dielectric constant or conductivity of the metal powder (6).

13. The method according to claim 11, characterized in that, The step of generating vibration or impact excitation using the densification excitation mechanism (1.3.1) includes: using a centrifugal hammer disposed inside the electrostatic carrier (1.3) to generate periodic shock waves as the electrostatic carrier (1.3) rotates.

14. The method according to claim 11, characterized in that, The method further includes: using a negative pressure powder suction device (8) and a powder collector (5) to perform directional adsorption and recovery of the metal powder (6) suspended outside the forming area or under microgravity.

Images