Additive-free lunar soil continuous forming device

Abstract

The invention belongs to the technical field of forming equipment, and particularly relates to an additive-free lunar soil continuous forming device. The additive-free lunar soil continuous forming device comprises a box body, a double-shaft platform, a heat insulation ceramic plate, a heat insulation ceramic cylinder, an induction coil, a crucible, a plunger and a feeding pipe. The box body has an inner cavity. The double-shaft platform is installed in the inner cavity and located at the bottom of the box body. The heat insulation ceramic plate is installed on the double-shaft platform. The heat insulation ceramic cylinder is installed in the inner cavity. And the induction coil is wound on the peripheral surface of the heat insulation ceramic cylinder. The crucible is coaxially installed in the heat insulation ceramic cylinder, a nozzle is arranged at the bottom of the crucible, and the nozzle is located above the heat insulation ceramic plate and used for spraying lunar soil onto the heat insulation ceramic plate. One end of the plunger is slidably arranged in the crucible, and the other end extends out of the inner cavity. One end of the feeding pipe extends out of the inner cavity, and the other end is close to the top of the crucible; the embodiment of the invention provides an additive-free lunar soil continuous forming device which can facilitate lunar soil and can realize continuous forming of the lunar soil without an additional adhesive or additive.

Description

Technical Field

[0001] This invention belongs to the field of molding equipment technology, and specifically relates to an additive-free continuous molding device for lunar soil. Background Technology

[0002] As human deep space exploration continues to deepen, the construction of lunar bases has become an important goal of national space strategies. However, the Moon is approximately 380,000 kilometers from Earth, making the transportation of building materials from Earth extremely costly, with each kilogram of materials costing millions of dollars. This makes traditional Earth transportation methods unsuitable for large-scale lunar base construction. Therefore, in-situ lunar resource utilization (ISRU) technology has become a key technological development direction for lunar base construction. Among these technologies, lunar regolith 3D printing technology, which can directly utilize the weathered layer (lunar regolith) on the lunar surface as raw material, has emerged as one of the most promising solutions.

[0003] Currently, research institutions both domestically and internationally have proposed various methods for 3D printing lunar regolith, mainly including sintering, laser melting, and geopolymer bonding. For example, China's Chang'e-8 mission plans to use microwave sintering and vacuum hot pressing technologies to manufacture high-strength lunar regolith bricks, whose compressive strength can reach more than three times that of ordinary red bricks. These bricks also employ traditional Chinese mortise and tenon joints to reduce reliance on adhesives. Furthermore, the European Space Agency (ESA) and NASA have also explored additive manufacturing technologies for lunar regolith based on solar-powered focused sintering and laser melting.

[0004] These methods generally face problems such as high energy consumption, brittle materials, and complex equipment. In terms of materials, existing technologies also have certain limitations. For example, some studies use a mixture of lunar regolith and Earth-borne binders (such as photosensitive resins and alkali activators) for 3D printing, but the binder typically accounts for more than 20% of the material, still relying on Earth for supply, making it uneconomical. Furthermore, components relying solely on lunar regolith sintering often have high porosity and poor mechanical properties, making it difficult to meet the requirements of load-bearing structures for lunar bases (such as solar panel supports and communication bases). Summary of the Invention

[0005] In view of the above problems, this application provides an additive-free lunar soil continuous molding device that can utilize lunar soil and achieve continuous molding of lunar soil without additional binders or additives.

[0006] This application provides an additive-free lunar soil continuous molding device, including a housing, a biaxial platform, a heat-insulating ceramic plate, a heat-insulating ceramic cylinder, an induction coil, a crucible, a plunger, and a feeding pipe. The housing has an internal cavity.

[0007] A dual-axis platform is installed within the inner cavity and located at the bottom of the housing. A heat-insulating ceramic plate is installed on the dual-axis platform. A heat-insulating ceramic cylinder is installed within the inner cavity. An induction coil is wound around the outer circumferential surface of the heat-insulating ceramic cylinder. A crucible is coaxially installed within the heat-insulating ceramic cylinder, and its bottom has a nozzle located above the heat-insulating ceramic plate. The nozzle is used to spray lunar soil onto the heat-insulating ceramic plate. One end of a plunger is slidably disposed within the crucible, and the other end extends out of the inner cavity. One end of a feeding pipe extends out of the inner cavity, and the other end is positioned near the top of the crucible.

[0008] This invention utilizes lunar regolith as a material, enabling high-precision, high-strength continuous 3D printing without additional binders or additives. Specifically, the entire molding process involves feeding material through a feeding tube, heating the lunar regolith with an induction coil to melt it, and then extruding it through a plunger, achieving continuous feeding and simultaneous melting. During the feeding stage, pre-treated lunar regolith powder is continuously conveyed to the heating zone (heated by the induction coil) through the feeding tube. Under controlled temperature (1200~1500℃), the lunar regolith partially melts or sinters, with some unmelted particles forming a dispersed reinforcing phase within the material, uniformly distributed in the matrix. This second-phase strengthening mechanism effectively improves the mechanical properties of the molded component. The molten lunar regolith is ejected through a nozzle (diameter range Φ5~15 mm, selectable from various high-temperature resistant materials such as silicon nitride and zirconium oxide), and deposited layer by layer under the control of a biaxial platform (acceleration range 0.2~0.5g), achieving a molding speed of 20~40 mm / s. During this process, the molten lunar soil acts on the solidified structure below, effectively refining the solidified structure of the sample to obtain a fine-grained structure and effectively avoiding anisotropy. The intensity of the molten lunar soil's action can be adjusted by changing the speed of the plunger moving above the crucible, thereby controlling the transformation of the formed sample's microstructure from fine-grained to near-spherulitic. Small crystal sizes can effectively improve the material's strength.

[0009] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a feed tube. One end of the feed tube is installed at the end of the crucible furthest from the heat-insulating ceramic plate, the inner surface of the feed tube and the inner surface of the crucible are curved, and the end of the feeding pipe near the crucible extends into the inner side of the feed tube.

[0010] In some embodiments, the inner diameter of the feed tube gradually increases from one end near the crucible to the other end away from the crucible.

[0011] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a feeding bin. The feeding bin is installed at and communicates with one end of the feeding pipe located outside the inner cavity.

[0012] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a conveyor belt for conveying lunar soil to the feeding bin.

[0013] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a worktable and a vacuum pump. The housing is mounted on the worktable. The vacuum pump is mounted on the worktable and is used to extract air from the inner cavity to create a vacuum in the inner cavity.

[0014] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a serpentine cooling pipe and a chiller. The serpentine cooling pipe is installed on the outer surface of the housing. The chiller is installed on the worktable and connected to the serpentine cooling pipe.

[0015] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes an infrared thermal imager. The infrared thermal imager is mounted on the worktable for monitoring the temperature of the inner cavity.

[0016] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a controller. The controller is mounted on the worktable and is used to control and monitor the induction coil, dual-axis platform, plunger, vacuum pump, chiller, and infrared thermal imager. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an additive-free lunar soil continuous molding device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of the box provided in an embodiment of the present invention; Figure 3 This is an assembly diagram of the heat-insulating ceramic cylinder and crucible provided in an embodiment of the present invention; Figure 4 This is a simulated lunar soil image for the present invention; Figure 5 This is a light mirror image of a simulated lunar soil cross-section for this invention. Detailed Implementation

[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0020] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "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 application 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 application.

[0021] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0022] In the description of this application, it should be noted that, unless otherwise expressly 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] Currently, research institutions both domestically and internationally have proposed various methods for 3D printing lunar regolith, mainly including sintering, laser melting, and geopolymer bonding. For example, China's Chang'e-8 mission plans to use microwave sintering and vacuum hot pressing technologies to manufacture high-strength lunar regolith bricks, whose compressive strength can reach more than three times that of ordinary red bricks. These bricks also employ traditional Chinese mortise and tenon joints to reduce reliance on adhesives. Furthermore, the European Space Agency (ESA) and NASA have also explored additive manufacturing technologies for lunar regolith based on solar-powered focused sintering and laser melting.

[0024] These methods generally face problems such as high energy consumption, brittle materials, and complex equipment. In terms of materials, existing technologies also have certain limitations. For example, some studies use a mixture of lunar regolith and Earth-borne binders (such as photosensitive resins and alkali activators) for 3D printing, but the binder typically accounts for more than 20% of the material, still relying on Earth for supply, making it uneconomical. Furthermore, components relying solely on lunar regolith sintering often have high porosity and poor mechanical properties, making it difficult to meet the requirements of load-bearing structures for lunar bases (such as solar panel supports and communication bases).

[0025] To solve the above problems, such as Figures 1 to 3As shown, this application provides an additive-free lunar soil continuous molding device, including a housing 1, a biaxial platform 2, a heat-insulating ceramic plate 3, a heat-insulating ceramic cylinder 4, an induction coil 5, a crucible 6, a plunger 7, and a feeding pipe 8. The housing 1 has an inner cavity. The biaxial platform 2 is installed in the inner cavity and located at the bottom of the housing 1. The heat-insulating ceramic plate 3 is installed on the biaxial platform 2. The heat-insulating ceramic cylinder 4 is installed in the inner cavity. The induction coil 5 is wound around the outer circumferential surface of the heat-insulating ceramic cylinder 4. The crucible 6 is coaxially installed in the heat-insulating ceramic cylinder 4, and its bottom has a nozzle 9, which is located above the heat-insulating ceramic plate 3. The nozzle 9 is used to spray molten lunar soil onto the heat-insulating ceramic plate 3. One end of the plunger 7 is slidably disposed inside the crucible 6, and the other end extends out of the inner cavity. One end of the feeding pipe 8 extends out of the inner cavity, and the other end is disposed near the top of the crucible 6. In addition, the housing 1 is also provided with a transparent observation window.

[0026] This invention utilizes lunar regolith as a material, enabling high-precision, high-strength continuous 3D printing without additional binders or additives. Specifically, the entire molding process involves feeding material through a feeding pipe 5, heating it with an induction coil 5 to melt the lunar regolith, and then extruding it through a plunger 7, achieving continuous feeding and simultaneous melting. During the feeding stage, pre-treated lunar regolith powder is continuously conveyed to the heating zone (heated by the induction coil 5) through a feeding pipe 8. Under controlled temperature (1200~1500℃), the lunar regolith is partially melted or sintered, with some unmelted particles forming a dispersed reinforcing phase within the material, uniformly distributed in the matrix. This second-phase strengthening mechanism effectively improves the mechanical properties of the molded component. The molten lunar regolith is ejected through a nozzle 9 (diameter range Φ5~15 mm, selectable from various high-temperature resistant materials such as silicon nitride and zirconium oxide), and deposited layer by layer under the control of a biaxial platform 2 (acceleration range 0.2~0.5g), achieving a molding speed of 20~40 mm / s. During this process, the molten lunar soil acts on the solidified structure below, effectively refining the solidified structure of the sample to obtain a fine-grained structure and effectively avoiding anisotropy. The intensity of the molten lunar soil's action can be adjusted by changing the moving speed of the plunger 7 above the crucible 6, thereby controlling the transformation of the formed sample's structure from fine-grained to near-spherulitic. Small crystal sizes can effectively improve the material's strength.

[0027] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a feed tube 10. One end of the feed tube 10 is installed at the end of the crucible 6 away from the heat-insulating ceramic plate 3, and the inner side of the feed tube 10 and the inner side of the crucible 6 are arc-shaped transitions. The end of the feeding pipe 8 near the crucible 6 extends into the inner side of the feed tube 10.

[0028] It should be noted that the material guide cylinder 10 and the crucible 6 are made of the same material, and the material guide cylinder 10 and the crucible 6 can be integrally formed. The inner side of the material guide cylinder 10 and the inner side of the crucible 6 are connected by an arc shape, which facilitates the smooth introduction of lunar soil into the crucible 6 and avoids lunar soil adhering at the junction of the material guide cylinder 10 and the crucible 6.

[0029] Based on the above, to facilitate the installation and fixing of the crucible 6, the additive-free lunar soil continuous molding device further includes a support member 11. The support member 11 is installed on the inner side of the inner cavity, and both ends of the support member 11 are fixed to the inner side of the inner cavity by bolts. The support member 11 is sleeved on the outside of the crucible 6, such that the guide cylinder 10 is located above the support member 11, and the crucible 6 is located below the support member 11. In this way, the outer side of the guide cylinder 10 abuts against the support member 11, so that the support member 11 supports the guide cylinder 10 and the crucible 6. To facilitate the fixing of the guide cylinder 10 and the crucible 6, the guide cylinder 10 and the support member 11 can be fixed with bolts or screws. The heat-insulating ceramic cylinder 4 can also be fixed to the support member 11 with bolts or screws. In order to make the crucible 6 more stable, the bottom of the heat-insulating ceramic cylinder 4 is a sealing end. The bottom of the crucible 6 is placed on the bottom of the heat-insulating ceramic cylinder 4 and in contact with it. In addition, in order to facilitate the extrusion of lunar soil, a through hole is provided at the bottom of the heat-insulating ceramic cylinder 4. The through hole is coaxial with the axis of the nozzle 9, and the inner diameter of the through hole is larger than the diameter of the nozzle 9.

[0030] In some embodiments, the inner diameter of the feed tube 10 gradually increases from one end near the crucible 6 to the other end away from the crucible 6. After the plunger 7 has finished extruding, the plunger 7 detaches from the crucible. At this time, lunar soil is added to the feed tube 8, and the lunar soil slides directly into the crucible 6 through the feed tube 10, avoiding interference between the feed tube 8 and the plunger 7, and also facilitating the entry of the lunar soil into the crucible 6.

[0031] In some embodiments, an additive-free continuous molding apparatus for lunar soil further includes a feeding bin. The feeding bin is installed at one end of the feeding pipe 8 located outside the inner cavity and is connected thereto.

[0032] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a conveyor belt for conveying lunar soil to a feeding hopper, facilitating the rapid and efficient conveying of lunar soil to the feeding hopper via the conveyor belt.

[0033] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a worktable 12 and a vacuum pump. The worktable 12 housing is mounted on the worktable. The vacuum pump, mounted on the worktable 12, is used to extract air from the inner cavity to create a vacuum state, simulating or adapting to the vacuum environment on the moon and ensuring the molding process is unaffected by Earth's atmosphere. The vacuum pump maintains the vacuum in the inner cavity, controlling pressure fluctuations within ±(0.25~0.5) Pa. Furthermore, a valve is provided at the end of the feeding pipe 8 located outside the inner cavity, so that when the valve is closed, the inner cavity is vacuumed by the vacuum pump, preventing air from flowing into the inner cavity through the feeding pipe 8.

[0034] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a serpentine cooling pipe 13 and a chiller. The serpentine cooling pipe 13 is installed on the outer side of the housing 1. The chiller is installed on the worktable 12 and is connected to the serpentine cooling pipe 13 to improve the operational stability of all components of the apparatus. Furthermore, the serpentine cooling pipe 13 and the chiller form a circulation pipeline.

[0035] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes an infrared thermal imager or a thermocouple. The infrared thermal imager is mounted on the worktable 12 and is used to monitor the temperature of the inner cavity, primarily the temperature inside the crucible 6.

[0036] In some embodiments, an additive-free lunar soil continuous molding apparatus further includes a controller 14. The controller 14 can be an embedded processor or a PLC. The controller 14 is mounted on the worktable 12 and is used to control and monitor the induction coil 5, the dual-axis platform 2, the plunger 7, the vacuum pump, the chiller, and the infrared thermal imager. The controller 14 includes a control panel to monitor and display in real time the heating temperature of the induction coil 5, the moving speed of the dual-axis platform 2, the extrusion speed and pressure of the plunger 7, the air extraction speed of the vacuum pump, and the temperature control by the chiller and the infrared thermal imager.

[0037] Based on the above, a vacuum pump maintains the necessary vacuum environment, while the serpentine cooling pipe 13 and chiller ensure the thermal stability of the entire device. The heating power and extrusion parameters are adjusted in real-time via a control panel to ensure uniform molding and dimensional accuracy. A gradient heating and cooling program (50→10→2℃ / min) combined with an argon displacement system effectively suppresses microscopic defects caused by thermal stress while promoting thorough sintering of the lunar regolith. Compared to the more common method of laser cladding, this significantly optimizes the microstructure of the lunar regolith, giving it high density and a dispersion-enhanced heterogeneous structure. Through multi-system coordinated control, feeding and continuous melting can be performed simultaneously, achieving continuous operation from feeding and melting to molding. This enables high-strength, high-precision continuous molding using only lunar regolith raw materials under simulated lunar environments (vacuum or low vacuum, extreme temperature differences).

[0038] In summary, the device of this invention enables lunar soil to be shaped solely based on its own properties, without the need for binders or modifying materials carried from Earth; vacuum and temperature control ensure stable operation of the device under extreme lunar conditions; the feeding and dual-axis platform work in tandem to support the manufacture of large-sized components; furthermore, it can integrate solar power supply, reducing dependence on Earth's energy and promoting energy efficiency.

[0039] Test case Experimental Comparative Example The raw material was a standard sample of low-titanium ore simulated lunar soil (CLSR-1). Mature selective laser cladding technology was used, employing an HK C250 machine manufactured by Wuhan Huake 3D Technology Co., Ltd. With a binder content of 15%, the process parameters were: laser power 18 W, laser scanning speed 3000 mm / s, powder layer thickness 0.20 mm, and laser energy density 0.0367 J / mm². 2 The density of the molded specimen reached 72.3%. The mechanical properties of the initially molded specimen were poor, with a compressive strength of 1.38 MPa.

[0040] Experimental Example 1 The graphite crucible was Φ50*100mm with a bottom aperture of 10mm. Simulated lunar soil powder was added to the mold as a reinforcing material. The vacuum was reduced to 90kPa and then stopped. The crucible was heated to 1200℃ to melt without holding. Immediately after complete melting, a plunger was loaded at a speed of 60mm / min, extruding the material into the fixed mold. The printing speed was 50 kg / h, followed by air cooling. The compressive strength was tested using a computer-controlled electronic universal testing machine. The formed specimen had a density of 56.0% and a compressive strength of 5.4 MPa.

[0041] Experimental Example 2 A graphite crucible with a diameter of 100*100mm and a bottom aperture of 15mm was used. Simulated lunar soil powder was added to the mold as a potential reinforcing material. The entire process was carried out under vacuum (90kPa), heated to 1250℃ to melt, and held at that temperature for half an hour. Immediately after complete melting, a plunger was loaded at a speed of 60mm / min, extruding the material into a fixed mold. The printing speed was 50 kg / h, followed by air cooling. The formed sample had a density of 82.1% and a compressive strength of 62.1 MPa. Example 3 The graphite crucible was Φ100*100mm with a bottom aperture of 15mm. Simulated lunar soil powder was added to the mold as a possible reinforcing material. The entire process was carried out under vacuum (90kPa), heated to 1250 ℃ to melt, and held at that temperature for half an hour. After complete melting, the plunger was immediately loaded at a speed of 60 mm / min and extruded into the mold, which moved with the platform at a speed of 20 mm / s. The printing speed was 50 kg / h, followed by air cooling. The formed sample had a density of 91.0% and a compressive strength of 73.2 MPa.

[0042] Through comparison with the experimental comparative examples and experimental examples 1-3, it can be seen that the compressive strength of the experimental comparative example is 1.38 MPa, which is poor in mechanical properties and is much lower than that of experimental examples 1-3.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0044] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit this application. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An additive-free lunar soil continuous forming device, characterized in that, The utility model relates to a lunar soil melting device, comprising: a box body having an inner cavity; a double-shaft platform installed in the inner cavity and located at the bottom of the box body; a heat-insulating ceramic plate installed on the double-shaft platform; a heat-insulating ceramic cylinder installed in the inner cavity; an induction coil wound around the outer circumferential surface of the heat-insulating ceramic cylinder; a crucible coaxially installed in the heat-insulating ceramic cylinder, the bottom of the crucible having a nozzle located above the heat-insulating ceramic plate, the nozzle being used to spray lunar soil onto the heat-insulating ceramic plate; a plunger having one end slidingly arranged in the crucible and the other end extending out of the inner cavity; a feeding pipe having one end extending out of the inner cavity and the other end arranged close to the top of the crucible.

2. The additive-free lunar soil continuous forming device according to claim 1, characterized in that, Further comprising: a material guiding cylinder installed at one end of the crucible away from the heat-insulating ceramic plate, the inner side surface of the material guiding cylinder being arc-shapedly transitioned with the inner side surface of the crucible, and the end of the feeding pipe close to the crucible extending into the inner side of the material guiding cylinder.

3. The additive-free lunar soil continuous forming device according to claim 2, characterized in that, The inner diameter of the material guiding cylinder gradually increases from the end close to the crucible to the end away from the crucible.

4. The additive-free lunar soil continuous forming device according to claim 1, characterized in that, Further comprising: a feeding bin installed at one end of the feeding pipe located outside the inner cavity and in communication with the feeding pipe.

5. The additive-free lunar soil continuous forming device according to claim 4, characterized in that, Further comprising: a conveyor belt used to convey lunar soil into the feeding bin.

6. The additive-free lunar soil continuous forming device according to claim 1, characterized in that, Further comprising: a workbench on which the box body is installed; a vacuum pump installed on the workbench and used to extract air from the inner cavity so that the inner cavity is in a vacuum state.

7. The additive-free lunar soil continuous forming device according to claim 6, characterized in that, Further comprising: a serpentine cooling pipe installed on the outer side surface of the box body; a water chiller installed on the workbench and in communication with the serpentine cooling pipe.

8. The additive-free lunar soil continuous forming device according to claim 6, characterized in that, Further comprising: an infrared thermal imager installed on the workbench and used to monitor the temperature of the inner cavity.

9. The additive-free lunar soil continuous forming device according to claim 6, characterized in that, Further comprising: a controller installed on the workbench, the controller being used to control and monitor the induction coil, the double-shaft platform, the plunger, the vacuum pump, the water chiller, and the infrared thermal imager.

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