A method for preparing a degradable metal mesh based on a 3D printing mold

Abstract

A kind of degradable metal mesh preparation method based on 3D printing mold, the prepared degradable metal mesh has membrane body, and the membrane body has honeycomb-shaped through-hole structure;The cross section of honeycomb-shaped through-hole structure is composed of multiple regular hexagons.The preparation method comprises the following steps: S1 three-dimensional model design, S2 mold forming, S3 mold pretreatment;S4 smelting, S5 centrifugal casting, S6 cooling and demolding, S7 post-processing obtains the final degradable guided bone regeneration degradable metal mesh.Using the process of "direct 3D printing ceramic casting mold + centrifugal casting", the preparation process is high in precision and good in efficiency.

Description

Technical Field

[0001] This invention relates to the field of oral medicine technology, and in particular to a method for preparing a biodegradable metal mesh based on a 3D printed mold. Background Technology

[0002] Guided bone regeneration (GBR) is a core clinical approach for addressing insufficient bone volume in implantation sites and repairing bone defects caused by trauma, tumors, or inflammation. The key to its success lies in using a barrier membrane placed at the bone defect site. This membrane effectively blocks the ingrowth of rapidly migrating fibroblasts and epithelial cells into the defect area, thereby creating a relatively stable and undisturbed environment for the proliferation and differentiation of osteoblasts and blood vessels.

[0003] An ideal GBR barrier membrane should possess the following characteristics: good biocompatibility and biosafety; appropriate mechanical strength to resist soft tissue stress and maintain space for bone regeneration; controllable degradation performance, with a degradation cycle that matches the bone tissue regeneration cycle; and a porous structure that serves as a scaffold to promote bone ingrowth.

[0004] Currently, the GBR membranes widely used in clinical practice mainly include non-degradable membranes (such as titanium mesh and expanded polytetrafluoroethylene (e-PTFE) membranes) and degradable membranes (such as collagen membranes and polylactic acid membranes). Non-degradable membranes, especially titanium mesh, while providing excellent space maintenance capabilities, suffer from drawbacks such as high rigidity, difficulty in intraoperative shaping, easy exposure leading to infection, and the need for secondary surgery for removal, increasing patient suffering and financial burden. Degradable membranes, such as collagen membranes, avoid secondary surgery, but their mechanical strength is generally insufficient, making them difficult to effectively support complex bone defects. Furthermore, the degradation rate is difficult to control precisely, often resulting in premature loss of barrier function or long-term residue affecting bone healing.

[0005] Applying biodegradable metals to GBR membranes faces several challenges: First, a simple dense metal film lacks the necessary porous structure, hindering nutrient transport and cell migration. Second, an unreasonable pore design can lead to stress concentration points and corrosion initiation points in the interpore areas, resulting in premature structural failure. Third, the matching of degradation behavior with the bone regeneration cycle still requires optimization through sophisticated structural design. Therefore, developing a method for preparing biodegradable metal meshes based on 3D-printed molds that combines excellent mechanical support, controllable degradation rate, ideal porous structure, and effective guidance of bone regeneration has become an urgent problem for those skilled in the art. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing biodegradable metal mesh based on 3D printing molds. This method can prepare biodegradable porous metal mesh suitable for oral restoration and for maxillofacial bone repair. The prepared biodegradable metal mesh has a reasonable structure, excellent mechanical behavior, and controllable degradation behavior.

[0007] The above-mentioned objectives of the present invention are achieved through the following technical measures.

[0008] A method for preparing a biodegradable metal mesh based on a 3D printed mold is provided. The prepared biodegradable metal mesh has a membrane body made of biodegradable metal, and the membrane body has a honeycomb-like through-hole structure. The cross-section of the honeycomb-shaped through-hole structure is composed of multiple regular hexagons. Any one of the regular hexagons is used as the central regular hexagon, and any adjacent regular hexagons share a side with the central regular hexagon. They are arranged radially in sequence to form the cross-section of the overall honeycomb-shaped through-hole structure. The diameter of the inscribed circle of any regular hexagon is 0.5-1.2 mm, and the wall thickness of the hole between adjacent regular hexagons is 100-500 μm; The preparation method includes the following steps: S1, 3D model design, specifically: Construct a three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure. S2, mold forming, specifically: Based on the three-dimensional digital model obtained in S1, 3D printing technology was used to print a casting ceramic negative mold with a corresponding honeycomb cavity using a castable ceramic-based embedding material. S3, mold pretreatment, specifically: The ceramic negative mold obtained by S2 printing is subjected to programmed drying and sintering. After drying, the moisture content of the mold is ≤1%. Sintering gives the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 200-300℃ for 2-3 hours. After sintering, the temperature is lowered to the preheating temperature of 200-300℃. S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas with a purity of ≥99.9% as a protective atmosphere, maintaining an ambient oxygen content of ≤0.1%. The smelting process is based on the complete melting of high-purity biodegradable metals without oxidation or component loss, and controls the inertness of the smelting environment and the temperature to match the melting characteristics of biodegradable metals. S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of inert gas with a purity of ≥99.9% and the condition that the oxygen content of the environment is maintained at ≤0.1% throughout the casting process, the molten biodegradable metal liquid is poured into the mold runner. The centrifuge is started so that the biodegradable metal liquid is filled into various parts of the honeycomb cavity under the centrifugal force. S6, Cooling and Demolding, specifically: After casting is completed, under controlled conditions, a gradient cooling process is used to first cool the casting temperature naturally to 400℃, and then cool it to room temperature at a rate of 5-15℃ / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting. S7, post-processing, specifically: The castings are cut, ground, polished, cleaned and disinfected to obtain the final biodegradable metal mesh.

[0009] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the printing accuracy of the 3D printing technology in S2 meets the requirements of cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

[0010] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printing molds, when preparing biodegradable metal mesh from magnesium and magnesium alloy raw materials, the castable ceramic-based embedding material comprises, by mass fraction: 82% fused white corundum powder, 8% mullite powder, 7% silica sol with 30wt% SiO2 content, 0.3% sodium polycarboxylate, and 2.7% boric acid; the raw materials are mixed with deionized water at a mass ratio of 1:0.35 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 50-80 mPa·s, suitable for photopolymerization or extrusion 3D printing. When preparing biodegradable metal mesh from zinc and zinc alloy raw materials, the castable ceramic-based embedding material comprises, by mass fraction, 78% fused silica powder, 10% bauxite powder, 9% aluminate cement, 0.5% sodium hexametaphosphate, and 2.5% magnesium oxide; the raw materials are mixed with deionized water at a mass ratio of 1:0.32 and stirred evenly to prepare a 3D printing slurry, the viscosity of which is controlled at 40-70 mPa·s.

[0011] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the drying process in S3 is as follows: heating from room temperature to 40°C at a heating rate of 5-10°C / min, holding at that temperature for 1-2 hours; then heating to 60°C at a heating rate of 5-10°C / min, holding at that temperature for 1-2 hours; then heating to 80°C at a heating rate of 5-10°C / min, holding at that temperature for 1-2 hours. The sintering process in S3 is specifically as follows: Heat to 600℃ at a heating rate of 5-20℃ / min and hold for 1-2 hours; then heat to 1000℃ at a heating rate of 5-20℃ / min and hold for 1-3 hours; then heat to 1400℃ at a heating rate of 5-20℃ / min and hold for 2-4 hours.

[0012] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the inert gas in S4 is either argon or helium.

[0013] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the smelting process in S4 varies depending on the biodegradable metal material: When the biodegradable metal is ≥99.9 wt% ultra-high purity magnesium: heat to 300℃ at 10-15℃ / min and hold for 30 minutes, then heat to 680-700℃ at 8-10℃ / min and hold for 40-60 minutes, and finally cool to 660-670℃ at 5-8℃ / min before pouring; When the biodegradable metal is a medical-grade magnesium alloy: heat to 350℃ at 12-15℃ / min and hold for 40 minutes, then heat to 650-670℃ at 10℃ / min and hold for 50-70 minutes, and finally cool to 640-650℃ at 6-8℃ / min before pouring; When the degradable metal is ≥99.9 wt% pure zinc: heat to 200℃ at 15-20℃ / min and hold for 20 minutes, then heat to 450-460℃ at 10-12℃ / min and hold for 30-40 minutes, and finally cool to 430-440℃ at 8-10℃ / min before pouring; When the biodegradable metal is a medical-grade zinc alloy: heat to 250℃ at 12-15℃ / min and hold for 30 minutes, then heat to 480-500℃ at 9-11℃ / min and hold for 40-50 minutes, and finally cool to 450-460℃ at 7-9℃ / min before pouring.

[0014] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the inert gas in S5 is either argon or helium.

[0015] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is one of argon or helium.

[0016] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, in step S7, the cutting is carried out by laser cutting or wire cutting, with a smooth cut without burrs and a dimensional error of ≤±0.1mm; the grinding is carried out by sandpaper or grinding wheel in stages to remove surface defects; the polishing is carried out by mechanical polishing or chemical polishing to make the surface roughness Ra≤0.8μm; the cleaning is carried out by ultrasonic cleaning with organic solvents or ultrasonic cleaning with deionized water to remove surface impurities; the disinfection is carried out by high-temperature steam disinfection at 121℃ and 0.1MPa for 15-30 minutes.

[0017] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the thickness of the membrane body is 0.3-2 mm.

[0018] Preferably, in the above-mentioned method for preparing biodegradable metal mesh based on 3D printed molds, the biodegradable metal is ultra-high purity magnesium or medical magnesium alloy or pure zinc or medical zinc alloy with a content of not less than 99.9 wt%.

[0019] This invention discloses a method for preparing a biodegradable metal mesh based on a 3D-printed mold. This method can prepare a biodegradable porous metal mesh for oral and maxillofacial bone repair. The biodegradable porous metal mesh comprises a membrane body made of biodegradable metal, the membrane body having a honeycomb-like perforated structure. The cross-section of the honeycomb-like perforated structure is composed of multiple regular hexagons, with any one regular hexagon serving as the central hexagon. Adjacent regular hexagons share a side with the central hexagon, arranged radially to form the overall cross-section of the honeycomb-like perforated structure. The inscribed circle diameter of any one regular hexagon is 0.5-1.2 mm, and the wall thickness between adjacent regular hexagons is 100-500 μm. The biodegradable porous metal mesh, with its honeycomb-like perforated structure, maintains a high porosity (typically >50%) to facilitate material exchange and cell migration, while also possessing mechanical support capabilities far exceeding those of similar biodegradable polymer membranes. It can effectively resist soft tissue pressure within the oral cavity, providing a durable and stable space for bone regeneration. Using biodegradable metals such as high-purity magnesium (99.9%), ultra-high-purity magnesium (99.99%), medical-grade magnesium alloys, pure zinc, or medical-grade zinc alloys significantly reduces the accelerating effect of impurity elements on electrochemical corrosion, making the degradation rate more uniform and controllable. Furthermore, the degradation product, magnesium ions, is a known potent osteogenic promoting factor. The honeycomb structure evenly distributes the degradation area, avoiding rapid fracture caused by stress concentration in the "narrow bridge" areas between traditional circular holes. This results in a smoother, more controllable degradation process, and the degradation cycle is more easily matched with the 4–6 month bone regeneration cycle. The selected high-purity magnesium, ultra-high-purity magnesium, medical-grade magnesium alloys, pure zinc, or medical-grade zinc alloys have excellent biocompatibility. The pore size (0.5-1.2 mm) of the honeycomb units is carefully designed to allow the free passage of body fluids, nutrients, and osteoblast-related cells while effectively blocking the invasion of larger fibroblasts, achieving an ideal "selective barrier" function.

[0020] The key innovation of the preparation method provided by this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, thus shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the biodegradable molten metal, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and exhibits good performance consistency, making it suitable for large-scale production. The preparation process boasts high precision and efficiency. Attached Figure Description

[0021] The invention will be further described with reference to the accompanying drawings, but the contents of the drawings do not constitute any limitation on the invention.

[0022] Figure 1 This is a schematic diagram of the structure of a biodegradable metal mesh prepared by a method for preparing biodegradable metal mesh based on a 3D printed mold according to the present invention.

[0023] exist Figure 1 Including: Membrane body 100, regular hexagon 200, pore wall 300. Detailed Implementation

[0024] The present invention will be further described in conjunction with the following embodiments.

[0025] Example 1 A method for preparing biodegradable metal mesh based on 3D printed molds is disclosed, which is used to prepare biodegradable porous metal mesh. The prepared biodegradable porous metal mesh is as follows: Figure 1 As shown, a membrane body 100 made of biodegradable metal is provided, and the membrane body 100 has a honeycomb-shaped through-hole structure.

[0026] The cross-section of the honeycomb-shaped through-hole structure is composed of multiple regular hexagons 200. Any one of the regular hexagons 200 serves as the central hexagon, and adjacent regular hexagons share a side with the central hexagon, arranged radially in sequence to form the overall cross-section of the honeycomb-shaped through-hole structure. For example... Figure 1 In the diagram, a regular hexagon A is the central hexagon, and six other regular hexagons are adjacent to A: B1, B2, B3, B4, B5, and B6. Each of B1, B2, B3, B4, B5, and B6 shares an edge with A. Similarly, a regular hexagon B6 is the central hexagon, and six other regular hexagons are adjacent to B6: B1, A, B5, C1, C2, and C3. Each of B1, A, B5, C1, C2, and C3 shares an edge with B6. The cross-sections of the honeycomb-like perforated structure are arranged radially to form the whole.

[0027] The diameter of the inscribed circle of any regular hexagon 200 is 0.5-1.2 mm, and the thickness of the hole wall 300 between adjacent regular hexagons 200 is 100-500 μm.

[0028] This biodegradable porous metal mesh for oral and maxillofacial bone repair has an overall membrane structure, with a membrane thickness of 0.3-2 mm.

[0029] As a preferred embodiment, the biodegradable porous metal mesh for maxillofacial bone repair may also have screw holes (not shown in the figure) for fixation at the edge of the membrane body 100. The diameter of the screw holes is 0.8-2.5 mm.

[0030] This biodegradable porous metal mesh for dental restoration uses ultra-high purity magnesium, medical-grade magnesium alloy, pure zinc, or medical-grade zinc alloy with a biodegradable metal content of not less than 99.9 wt%. Preferably, the high-purity magnesium is 99.99 wt% ultra-high purity magnesium.

[0031] The biodegradable porous metal mesh for oral restoration prepared by the method of the present invention has the following advantages: 1. A perfect combination of biomimetic structure and mechanical properties: Utilizing the optimal hexagonal honeycomb structure found in nature, this structure possesses the highest specific stiffness and specific strength in material mechanics. This invention miniaturizes it to the micrometer scale and applies it to a metal mesh. This allows the metal mesh to maintain a high porosity (typically >50%) to facilitate material exchange and cell migration, while possessing mechanical support capabilities far exceeding those of similar biodegradable polymer membranes. It can effectively resist soft tissue pressure within the oral cavity, providing a durable and stable space for bone regeneration.

[0032] 2. Optimized degradation behavior and biological function: (1) The use of biodegradable metals such as high-purity magnesium (99.9%) and ultra-high-purity magnesium (99.99%) or medical magnesium alloy or pure zinc or medical zinc alloy significantly reduces the accelerating effect of impurity elements on electrochemical corrosion, making the degradation rate more uniform and controllable, and the degradation product magnesium ions are known to be potent osteogenic promoting factors.

[0033] (2) The honeycomb structure distributes the degradation area evenly, avoiding the rapid fracture caused by stress concentration in the "narrow bridge" area between traditional round holes, making the degradation process more gradual and controllable, and the degradation cycle more easily matched with the 4-6 month bone regeneration cycle.

[0034] 3. Excellent biocompatibility and selective barrier function: The selected high-purity magnesium, ultra-high-purity magnesium, or medical-grade magnesium alloy, or pure zinc or medical-grade zinc alloy have excellent biocompatibility. The pore size (0.5-1.2mm) of the honeycomb cells is carefully designed to allow the free passage of body fluids, nutrients, and osteoblast-related cells, while effectively blocking the invasion of larger fibroblasts, achieving an ideal "selective barrier" function.

[0035] 4. Convenient Clinical Operation and Personalized Adaptation: The metal mesh possesses a certain degree of flexibility, allowing surgeons to precisely bend and shape it according to the bone defect during surgery. Pre-set fixing holes and matching screws at the edges ensure secure implant fixation, simplifying operation. Combined with 3D-printed wax model technology, individualized customization based on patient CT data can be achieved, improving surgical precision and outcome.

[0036] 5. High-precision, repeatable advanced manufacturing process: The key innovation of this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the magnesium liquid, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and has good performance consistency, making it suitable for mass production.

[0037] The biodegradable porous metal mesh of the present invention can be used to prepare a medical device for guiding bone regeneration in maxillofacial surgery for bone defect repair. It can be used as a biodegradable metal barrier membrane to guide bone regeneration and repair bone defects in surgeries such as dental implants, maxillofacial surgery, and alveolar ridge augmentation. Its biomimetic porous structure provides mechanical support, controls tissue growth, and ultimately degrades safely in vivo.

[0038] The method for preparing biodegradable metal mesh based on 3D printed molds in this embodiment includes the following steps: S1, 3D model design, specifically: A three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure is constructed. The structure of the three-dimensional digital model of the biodegradable metal mesh corresponds to the structure of the specific biodegradable metal mesh to be prepared. A structure that does not include screw holes for fixing at the edge of the membrane body can be designed according to actual requirements. Alternatively, a structure with screw holes for fixing at the edge of the membrane body can be designed as needed. Those skilled in the art can flexibly choose according to actual needs and design the corresponding biodegradable three-dimensional digital model.

[0039] S2, mold forming, specifically: Based on the 3D digital model obtained from S1, 3D printing technology is used to print a casting ceramic negative mold with a corresponding honeycomb cavity using a castable ceramic-based embedding material. The castable ceramic-based embedding material consists of refractory aggregates, binders, dispersants, and sintering aids. The formulation of the castable ceramic-based embedding material needs to be adapted to the melting characteristics of the biodegradable metal: for zinc and zinc alloys with low melting points (melting temperature 419-650℃), a low-expansion formulation based on fused silica powder (such as formulation two) is preferred to avoid casting defects caused by the mismatch in thermal expansion between the mold and the molten metal. For magnesium and magnesium alloys with high melting points (melting temperature 650-850℃), a high-temperature resistant formulation based on corundum powder (such as formulation one) is preferred to ensure the structural stability of the mold at high temperatures. The particle size of each raw material needs to be controlled within 0.3-5μm to ensure the fluidity and molding accuracy of the 3D printing slurry, while avoiding pore blockage.

[0040] When preparing biodegradable metal meshes from magnesium and magnesium alloy raw materials, the castable ceramic-based embedding material, by mass fraction, includes: 82% fused white corundum powder, 8% mullite powder, 7% silica sol with 30wt% SiO2 content, 0.3% sodium polycarboxylate, and 2.7% boric acid. This formula is referred to as Formula 1. The raw materials are mixed with deionized water at a mass ratio of 1:0.35 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 50-80 mPa·s, suitable for photopolymerization or extrusion 3D printing. Preferably, the fused white corundum powder has a particle size of 1-5 μm, and the mullite powder has a particle size of 0.5-2 μm.

[0041] When preparing biodegradable metal meshes from zinc and zinc alloy raw materials, the castable ceramic-based embedding material, by mass fraction, comprises 78% fused silica powder, 10% bauxite powder, 9% aluminate cement, 0.5% sodium hexametaphosphate, and 2.5% magnesium oxide. This formula is referred to as Formula Two. The raw materials are mixed with deionized water at a mass ratio of 1:0.32 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 40-70 mPa·s. Preferably, the fused silica powder has a particle size of 1-3 μm, and the bauxite powder has a particle size of 0.3-1 μm.

[0042] This step uses high-precision 3D printing technology to achieve the following printing accuracy: cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

[0043] S3, mold pretreatment, specifically: The ceramic negative mold obtained from S2 printing is subjected to programmed drying and sintering. After drying, the moisture content of the mold is ≤1%. Sintering gives the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 200-300℃ for 2-3 hours. After sintering, the temperature is lowered to the preheating temperature of 200-300℃.

[0044] Specifically, the drying process in S3 is as follows: heat from room temperature to 40°C at a heating rate of 5-10°C / min and hold for 1-2 hours; then heat to 60°C at a heating rate of 5-10°C / min and hold for 1-2 hours; then heat to 80°C at a heating rate of 5-10°C / min and hold for 1-2 hours.

[0045] The sintering process in S3 is specifically as follows: Heat to 600℃ at a heating rate of 5-20℃ / min and hold for 1-2 hours; then heat to 1000℃ at a heating rate of 5-20℃ / min and hold for 1-3 hours; then heat to 1400℃ at a heating rate of 5-20℃ / min and hold for 2-4 hours.

[0046] S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas (argon or helium) with a purity of ≥99.9% as a protective atmosphere. The smelting process focuses on the complete melting of high-purity biodegradable metals without oxidation or component loss, and controls the inertness of the smelting environment and the temperature to match the melting characteristics of the biodegradable metals.

[0047] The smelting processes in S4 vary depending on the biodegradable metal material: When the biodegradable metal is ≥99.9 wt% ultra-high purity magnesium: heat to 300℃ at 10-15℃ / min and hold for 30 minutes, then heat to 680-700℃ at 8-10℃ / min and hold for 40-60 minutes, and finally cool to 660-670℃ at 5-8℃ / min before pouring; When the biodegradable metal is a medical-grade magnesium alloy: heat to 350℃ at 12-15℃ / min and hold for 40 minutes, then heat to 650-670℃ at 10℃ / min and hold for 50-70 minutes, and finally cool to 640-650℃ at 6-8℃ / min before pouring; When the degradable metal is ≥99.9 wt% pure zinc: heat to 200℃ at 15-20℃ / min and hold for 20 minutes, then heat to 450-460℃ at 10-12℃ / min and hold for 30-40 minutes, and finally cool to 430-440℃ at 8-10℃ / min before pouring; When the biodegradable metal is a medical-grade zinc alloy: heat to 250℃ at 12-15℃ / min and hold for 30 minutes, then heat to 480-500℃ at 9-11℃ / min and hold for 40-50 minutes, and finally cool to 450-460℃ at 7-9℃ / min before pouring.

[0048] S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of an inert gas (argon or helium) with a purity of ≥99.9%, and the oxygen content of the environment is maintained at ≤0.1% throughout the casting process, the molten biodegradable metal liquid is poured into the mold runner. The centrifuge is started, so that the biodegradable metal liquid is filled into various parts of the honeycomb cavity under the drive of centrifugal force.

[0049] S6, Cooling and Demolding, specifically: After casting is completed, the temperature is first naturally cooled to 400℃ under controlled conditions using a gradient cooling process, and then cooled to room temperature at a rate of 5-15℃ / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting.

[0050] The controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is either argon or helium.

[0051] S7, post-processing, specifically: The castings are cut, ground, polished, cleaned, and disinfected to obtain the final biodegradable metal mesh. In S7, cutting is performed using laser cutting or wire cutting, resulting in smooth, burr-free cuts with a dimensional error ≤ ±0.1mm. Grinding is done using sandpaper or grinding wheels in stages to remove surface defects. Polishing is done mechanically or chemically to achieve a surface roughness Ra ≤ 0.8μm. Cleaning involves sequentially using organic solvent ultrasonic cleaning or deionized water ultrasonic cleaning to remove surface impurities. Disinfection is performed using high-temperature steam sterilization at 121℃ and 0.1MPa for 15-30 minutes.

[0052] The key innovation of the preparation method provided by this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, thus shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the biodegradable molten metal, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and exhibits good performance consistency, making it suitable for large-scale production. The preparation process boasts high precision and efficiency.

[0053] Example 2 A method for preparing a biodegradable metal mesh based on a 3D printed mold includes the following steps: S1, 3D model design, specifically: Construct a three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure.

[0054] S2, mold forming, specifically: Based on the three-dimensional digital model obtained in S1, 3D printing technology was used to print a casting ceramic negative mold with a corresponding honeycomb cavity using castable ceramic-based embedding material.

[0055] When preparing biodegradable metal meshes from magnesium and magnesium alloy raw materials, the castable ceramic-based embedding material, by mass fraction, includes: 82% fused white corundum powder, 8% mullite powder, 7% silica sol with 30wt% SiO2 content, 0.3% sodium polycarboxylate, and 2.7% boric acid. This formula is referred to as Formula 1. The raw materials are mixed with deionized water at a mass ratio of 1:0.35 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 50-80 mPa·s, suitable for photopolymerization or extrusion 3D printing. Preferably, the fused white corundum powder has a particle size of 1-5 μm, and the mullite powder has a particle size of 0.5-2 μm.

[0056] When preparing biodegradable metal meshes from zinc and zinc alloy raw materials, the castable ceramic-based embedding material, by mass fraction, comprises 78% fused silica powder, 10% bauxite powder, 9% aluminate cement, 0.5% sodium hexametaphosphate, and 2.5% magnesium oxide. This formula is referred to as Formula Two. The raw materials are mixed with deionized water at a mass ratio of 1:0.32 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 40-70 mPa·s. Preferably, the fused silica powder has a particle size of 1-3 μm, and the bauxite powder has a particle size of 0.3-1 μm.

[0057] This step uses high-precision 3D printing technology to achieve the following printing accuracy: cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

[0058] S3, mold pretreatment, specifically: The ceramic negative mold obtained from S2 printing was subjected to programmed drying and sintering. After drying, the moisture content of the mold was ≤1%. Sintering gave the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 200℃ for 2 hours. After sintering, the temperature was lowered to the preheating temperature of 200℃.

[0059] Specifically, the drying process in S3 is as follows: the temperature is increased from room temperature to 40°C at a heating rate of 5°C / min and held for 1 hour; then the temperature is increased to 60°C at a heating rate of 5°C / min and held for 1 hour; then the temperature is increased to 80°C at a heating rate of 5°C / min and held for 1 hour.

[0060] The sintering process in S3 is specifically as follows: The temperature was increased to 600℃ at a heating rate of 5℃ / min and held for 1 hour; then the temperature was increased to 1000℃ at a heating rate of 5℃ / min and held for 1 hour; then the temperature was increased to 1400℃ at a heating rate of 5℃ / min and held for 2 hours.

[0061] S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas (argon) with a purity of ≥99.9% as a protective atmosphere. The smelting process focuses on the complete melting of high-purity biodegradable metals without oxidation or component loss, and controls the inertness of the smelting environment and the temperature to match the melting characteristics of the biodegradable metals.

[0062] The smelting processes in S4 vary depending on the biodegradable metal material: When the biodegradable metal is ≥99.9 wt% ultra-high purity magnesium: heat to 300℃ at 10-15℃ / min and hold for 30 minutes, then heat to 680-700℃ at 8-10℃ / min and hold for 40-60 minutes, and finally cool to 660-670℃ at 5-8℃ / min before pouring; When the biodegradable metal is a medical-grade magnesium alloy: heat to 350℃ at 12-15℃ / min and hold for 40 minutes, then heat to 650-670℃ at 10℃ / min and hold for 50-70 minutes, and finally cool to 640-650℃ at 6-8℃ / min before pouring; When the degradable metal is ≥99.9 wt% pure zinc: heat to 200℃ at 15-20℃ / min and hold for 20 minutes, then heat to 450-460℃ at 10-12℃ / min and hold for 30-40 minutes, and finally cool to 430-440℃ at 8-10℃ / min before pouring; When the biodegradable metal is a medical-grade zinc alloy: heat to 250℃ at 12-15℃ / min and hold for 30 minutes, then heat to 480-500℃ at 9-11℃ / min and hold for 40-50 minutes, and finally cool to 450-460℃ at 7-9℃ / min before pouring.

[0063] S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of inert gas (argon) with a purity of ≥99.9%, and with the oxygen content of the environment maintained at ≤0.1% throughout the casting process, molten biodegradable metal liquid is poured into the mold runner. The centrifuge is then started, allowing the biodegradable metal liquid to fill various parts of the honeycomb cavity under the drive of centrifugal force.

[0064] S6, Cooling and Demolding, specifically: After casting, the temperature is naturally cooled to 400°C under controlled conditions using a gradient cooling process, and then cooled to room temperature at a rate of 5°C / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting.

[0065] The controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is either argon or helium.

[0066] S7, post-processing, specifically: The castings are cut, ground, polished, cleaned, and disinfected to obtain the final biodegradable metal mesh. In S7, cutting is performed using laser cutting or wire cutting, resulting in smooth, burr-free cuts with a dimensional error ≤ ±0.1mm. Grinding is done using sandpaper or grinding wheels in stages to remove surface defects. Polishing is done mechanically or chemically to achieve a surface roughness Ra ≤ 0.8μm. Cleaning involves sequentially using organic solvent ultrasonic cleaning or deionized water ultrasonic cleaning to remove surface impurities. Disinfection is performed using high-temperature steam sterilization at 121℃ and 0.1MPa for 15 minutes.

[0067] The key innovation of the preparation method provided by this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, thus shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the biodegradable molten metal, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and exhibits good performance consistency, making it suitable for large-scale production. The preparation process boasts high precision and efficiency.

[0068] The method of this invention can effectively prepare biodegradable magnesium mesh and biodegradable zinc mesh made of ultra-high purity magnesium, medical magnesium alloy, pure zinc, or medical zinc alloy with a content of not less than 99.9 wt%. The prepared biodegradable magnesium mesh and biodegradable zinc mesh can be used as medical devices for bone defect regeneration in oral implantology, maxillofacial surgery, periodontal treatment, or trauma repair. In particular, they can be used as biodegradable guiding bone regeneration barrier membranes that do not require secondary surgery for removal.

[0069] This embodiment constructs a technology system with "ultra-high purity biodegradable metal materials + biomimetic honeycomb microstructure + direct 3D printing mold centrifugal casting process" as the core, and prepares biodegradable metal barrier membrane products with excellent mechanical properties, controllable degradation characteristics, bioactivity and clinical convenience.

[0070] Example 3 A method for preparing a biodegradable metal mesh based on a 3D printed mold, which is otherwise the same as in Example 1 or 2, except that the specific parameters of the following steps are different.

[0071] S1, 3D model design, specifically: Construct a three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure.

[0072] S2, mold forming, specifically: Based on the three-dimensional digital model obtained in S1, 3D printing technology was used to print a casting ceramic negative mold with a corresponding honeycomb cavity using castable ceramic-based embedding material.

[0073] This step uses high-precision 3D printing technology to achieve the following printing accuracy: cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

[0074] S3, mold pretreatment, specifically: The ceramic negative mold obtained from S2 printing was subjected to programmed drying and sintering. After drying, the moisture content of the mold was ≤1%. Sintering gave the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 300℃ for 3 hours. After sintering, the temperature was lowered to the preheating temperature of 300℃.

[0075] Specifically, the drying process in S3 is as follows: the temperature is increased from room temperature to 40°C at a heating rate of 10°C / min and held for 2 hours; then the temperature is increased to 60°C at a heating rate of 10°C / min and held for 2 hours; then the temperature is increased to 80°C at a heating rate of 10°C / min and held for 2 hours.

[0076] The sintering process in S3 is specifically as follows: The temperature was increased to 600℃ at a heating rate of 20℃ / min and held for 2 hours; then increased to 1000℃ at a heating rate of 20℃ / min and held for 3 hours; then increased to 1400℃ at a heating rate of 20℃ / min and held for 4 hours.

[0077] S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas (helium) with a purity of ≥99.9% as a protective atmosphere. The smelting process focuses on the complete melting of high-purity biodegradable metals without oxidation or component loss, and controls the inertness of the smelting environment and the temperature to match the melting characteristics of the biodegradable metals.

[0078] S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of inert gas (helium) with a purity of ≥99.9%, and with the oxygen content of the environment maintained at ≤0.1% throughout the casting process, molten biodegradable metal liquid is poured into the mold runner. The centrifuge is then started, allowing the biodegradable metal liquid to fill various parts of the honeycomb cavity under the drive of centrifugal force.

[0079] S6, Cooling and Demolding, specifically: After casting, the temperature is naturally cooled to 400°C under controlled conditions using a gradient cooling process, and then cooled to room temperature at a rate of 15°C / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting.

[0080] The controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is either argon or helium.

[0081] S7, post-processing, specifically: The castings are cut, ground, polished, cleaned, and disinfected to obtain the final biodegradable metal mesh. In S7, cutting is performed using laser cutting or wire cutting, resulting in smooth, burr-free cuts with a dimensional error ≤ ±0.1mm. Grinding is done using sandpaper or grinding wheels in stages to remove surface defects. Polishing is performed using mechanical or chemical polishing to achieve a surface roughness Ra ≤ 0.8μm. Cleaning involves sequentially using organic solvent ultrasonic cleaning or deionized water ultrasonic cleaning to remove surface impurities. Disinfection is performed using high-temperature steam sterilization at 121℃ and 0.1MPa for 30 minutes.

[0082] The preparation methods described in this embodiment can effectively produce biodegradable magnesium mesh and biodegradable zinc mesh made of ultra-high purity magnesium, medical magnesium alloy, pure zinc, or medical zinc alloy with a content of not less than 99.9 wt%. The prepared biodegradable magnesium mesh and biodegradable zinc mesh can be used as medical devices for bone defect regeneration in oral implantology, maxillofacial surgery, periodontal treatment, or trauma repair. In particular, they can be used as biodegradable guiding bone regeneration barrier membranes that do not require secondary surgery for removal.

[0083] The key innovation of the preparation method provided by this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, thus shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the biodegradable molten metal, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and exhibits good performance consistency, making it suitable for large-scale production. The preparation process boasts high precision and efficiency.

[0084] Example 4 A method for preparing a biodegradable metal mesh based on a 3D printed mold includes the following steps: S1, 3D model design, specifically: Construct a three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure.

[0085] S2, mold forming, specifically: Based on the three-dimensional digital model obtained in S1, 3D printing technology was used to print a casting ceramic negative mold with a corresponding honeycomb cavity using castable ceramic-based embedding material.

[0086] When preparing biodegradable metal meshes from magnesium and magnesium alloy raw materials, the castable ceramic-based embedding material, by mass fraction, includes: 82% fused white corundum powder, 8% mullite powder, 7% silica sol with 30wt% SiO2 content, 0.3% sodium polycarboxylate, and 2.7% boric acid. The raw materials are mixed with deionized water at a mass ratio of 1:0.35 and stirred evenly to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 50-80 mPa·s, suitable for photopolymerization or extrusion 3D printing. Preferably, the fused white corundum powder has a particle size of 1-5 μm, and the mullite powder has a particle size of 0.5-2 μm.

[0087] When preparing biodegradable metal meshes from zinc and zinc alloy raw materials, the castable ceramic-based embedding material, by mass fraction, comprises 78% fused silica powder, 10% bauxite powder, 9% aluminate cement, 0.5% sodium hexametaphosphate, and 2.5% magnesium oxide. The raw materials are mixed with deionized water at a mass ratio of 1:0.32 and stirred until homogeneous to prepare a 3D printing slurry. The viscosity of the slurry is controlled at 40-70 mPa·s. Preferably, the fused silica powder has a particle size of 1-3 μm, the bauxite powder has a particle size of 0.3-1 μm, and the aluminate cement is type CA-50.

[0088] This step uses high-precision 3D printing technology to achieve the following printing accuracy: cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

[0089] S3, mold pretreatment, specifically: The ceramic negative mold obtained from S2 printing was subjected to programmed drying and sintering. After drying, the moisture content of the mold was ≤1%. Sintering gave the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 250℃ for 2.5 hours. After sintering, the temperature was lowered to the preheating temperature of 250℃.

[0090] The sintering process in S3 is specifically as follows: The temperature was increased from room temperature to 40°C at a heating rate of 8°C / min and held for 1.5 hours; then increased to 60°C at a heating rate of 7°C / min and held for 1.5 hours; then increased to 80°C at a heating rate of 8°C / min and held for 1.2 hours.

[0091] The sintering process in S3 is specifically as follows: The temperature was increased to 600℃ at a heating rate of 10℃ / min and held for 1.5 hours; then increased to 1000℃ at a heating rate of 10℃ / min and held for 2 hours; then increased to 1400℃ at a heating rate of 15℃ / min and held for 3 hours.

[0092] S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas (argon or helium) with a purity of ≥99.9% as a protective atmosphere. The smelting process focuses on the complete melting of high-purity biodegradable metals without oxidation or component loss, and controls the inertness of the smelting environment and the temperature to match the melting characteristics of the biodegradable metals.

[0093] The smelting process in S4 is as follows: (1) When the degradable metal is ultra-high purity magnesium (≥99.9 wt%): heat up to 300℃ at 15℃ / min and hold for 30 minutes, then heat up to 700℃ at 9℃ / min and hold for 30 minutes, and finally cool down to 670℃ at 6℃ / min before pouring.

[0094] (2) When the biodegradable metal is a medical magnesium alloy: heat up to 350℃ at 13℃ / min and hold for 40 minutes, then heat up to 660℃ at 10℃ / min and hold for 60 minutes, and finally cool down to 650℃ at 7℃ / min before pouring.

[0095] (3) When the degradable metal is pure zinc (≥99.9 wt%): heat up to 200℃ at 18℃ / min and hold for 20 minutes, then heat up to 460℃ at 10℃ / min and hold for 35 minutes, and finally cool down to 440℃ at 9℃ / min before pouring.

[0096] (4) When the biodegradable metal is medical zinc alloy: heat up to 250℃ at 14℃ / min and hold for 30 minutes, then heat up to 500℃ at 10℃ / min and hold for 45 minutes, and finally cool down to 450℃ at 8℃ / min before pouring.

[0097] S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of an inert gas (argon or helium) with a purity of ≥99.9%, and the oxygen content of the environment is maintained at ≤0.1% throughout the casting process, the molten biodegradable metal liquid is poured into the mold runner. The centrifuge is started, so that the biodegradable metal liquid is filled into various parts of the honeycomb cavity under the drive of centrifugal force.

[0098] S6, Cooling and Demolding, specifically: After casting is completed, the temperature is first naturally cooled to 400°C under controlled conditions using a gradient cooling process, and then cooled to room temperature at a rate of 10°C / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting.

[0099] The controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is either argon or helium.

[0100] S7, post-processing, specifically: The castings are cut, ground, polished, cleaned, and disinfected to obtain the final biodegradable metal mesh. In S7, cutting is performed using laser cutting or wire cutting, resulting in smooth, burr-free cuts with a dimensional error ≤ ±0.1mm. Grinding is done using sandpaper or grinding wheels in stages to remove surface defects. Polishing is performed using mechanical or chemical polishing to achieve a surface roughness Ra ≤ 0.8μm. Cleaning involves sequentially using organic solvent ultrasonic cleaning or deionized water ultrasonic cleaning to remove surface impurities. Disinfection is performed using high-temperature steam sterilization at 121℃ and 0.1MPa for 20 minutes.

[0101] The preparation methods described in this embodiment can effectively produce biodegradable magnesium mesh and biodegradable zinc mesh made of ultra-high purity magnesium, medical magnesium alloy, pure zinc, or medical zinc alloy with a content of not less than 99.9 wt%. The prepared biodegradable magnesium mesh and biodegradable zinc mesh can be used as medical devices for bone defect regeneration in oral implantology, maxillofacial surgery, periodontal treatment, or trauma repair. In particular, they can be used as biodegradable guiding bone regeneration barrier membranes that do not require secondary surgery for removal.

[0102] The key innovation of the preparation method provided by this invention is the "direct 3D printing of ceramic casting molds + centrifugal casting" process. It eliminates multiple steps in the traditional lost-wax casting method, such as wax pattern making, embedding, and dewaxing, thus shortening the process. The directly printed mold has precise dimensions and good reproducibility, and combined with centrifugal casting, it ensures perfect filling of the biodegradable molten metal, making it particularly suitable for replicating complex microporous structures. The final casting is dense, has few defects, and exhibits good performance consistency, making it suitable for large-scale production. The preparation process boasts high precision and efficiency.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a biodegradable metal mesh based on a 3D printed mold, characterized in that, The prepared biodegradable metal mesh has a membrane body made of biodegradable metal, and the membrane body has a honeycomb-like through-hole structure; The cross-section of the honeycomb-shaped through-hole structure is composed of multiple regular hexagons. Any one of the regular hexagons is used as the central regular hexagon, and any adjacent regular hexagons share a side with the central regular hexagon. They are arranged radially in sequence to form the cross-section of the overall honeycomb-shaped through-hole structure. The diameter of the inscribed circle of any regular hexagon is 0.5-1.2 mm, and the wall thickness of the hole between adjacent regular hexagons is 100-500 μm; The preparation method includes the following steps: S1, 3D model design, specifically: Construct a three-dimensional digital model of a biodegradable metal mesh with a honeycomb-like perforated structure. S2, mold forming, specifically: Based on the three-dimensional digital model obtained in S1, 3D printing technology was used to print a casting ceramic negative mold with a corresponding honeycomb cavity using a castable ceramic-based embedding material. S3, mold pretreatment, specifically: The ceramic negative mold obtained by S2 printing is subjected to programmed drying and sintering. After drying, the moisture content of the mold is ≤1%. Sintering gives the mold a mechanical strength of ≥30MPa compressive strength and ≥5MPa flexural strength at room temperature, and high-temperature stability with no deformation or cracking after holding at a preheating temperature of 200-300℃ for 2-3 hours. After sintering, the temperature is lowered to the preheating temperature of 200-300℃. S4, smelting, specifically: High-purity biodegradable metal raw materials are smelted in an inert gas with a purity of ≥99.9% as a protective atmosphere, maintaining an ambient oxygen content of ≤0.1%. S5, centrifugal casting, specifically: The preheated ceramic negative mold is fixed in a centrifugal casting machine. Under the protective atmosphere of inert gas with a purity of ≥99.9% and the condition that the oxygen content of the environment is maintained at ≤0.1% throughout the casting process, the molten biodegradable metal liquid is poured into the mold runner. The centrifuge is started so that the biodegradable metal liquid is filled into various parts of the honeycomb cavity under the centrifugal force. S6, Cooling and Demolding, specifically: After casting is completed, under controlled conditions, a gradient cooling process is used to first cool the casting temperature naturally to 400℃, and then cool it to room temperature at a rate of 5-15℃ / min. After that, the ceramic mold is removed to obtain a biodegradable metal mesh casting. S7, post-processing, specifically: The castings are cut, ground, polished, cleaned and disinfected to obtain the final biodegradable metal mesh.

2. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: The 3D printing technology in S2 achieves printing accuracy that meets the requirements of cavity size error ≤ ±0.05mm, surface roughness Ra ≤ 5μm, and pore structure replication accuracy ≥ 95%.

3. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: When preparing biodegradable metal mesh from magnesium and magnesium alloy raw materials, the castable ceramic-based embedding material comprises, by mass fraction: 82% fused white corundum powder, 8% mullite powder, 7% silica sol with 30wt% SiO2 content, 0.3% sodium polycarboxylate, and 2.7% boric acid; the raw materials are mixed with deionized water at a mass ratio of 1:0.35 and stirred evenly to prepare a 3D printing slurry, the viscosity of which is controlled at 50-80 mPa·s; When preparing biodegradable metal mesh from zinc and zinc alloy raw materials, the castable ceramic-based embedding material comprises, by mass fraction, 78% fused silica powder, 10% bauxite powder, 9% aluminate cement, 0.5% sodium hexametaphosphate, and 2.5% magnesium oxide; the raw materials are mixed with deionized water at a mass ratio of 1:0.32 and stirred evenly to prepare a 3D printing slurry, the viscosity of which is controlled at 40-70 mPa·s.

4. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: The drying process in S3 is as follows: heat from room temperature to 40°C at a heating rate of 5-10°C / min and hold for 1-2 hours; then heat to 60°C at a heating rate of 5-10°C / min and hold for 1-2 hours; then heat to 80°C at a heating rate of 5-10°C / min and hold for 1-2 hours. The sintering process in S3 is specifically as follows: Heat to 600℃ at a heating rate of 5-20℃ / min and hold for 1-2 hours; then heat to 1000℃ at a heating rate of 5-20℃ / min and hold for 1-3 hours; then heat to 1400℃ at a heating rate of 5-20℃ / min and hold for 2-4 hours.

5. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: The inert gas in S4 is either argon or helium. The smelting processes in S4 vary depending on the biodegradable metal material: When the biodegradable metal is ≥99.9 wt% ultra-high purity magnesium: heat to 300℃ at 10-15℃ / min and hold for 30 minutes, then heat to 680-700℃ at 8-10℃ / min and hold for 40-60 minutes, and finally cool to 660-670℃ at 5-8℃ / min before pouring; When the biodegradable metal is a medical-grade magnesium alloy: heat to 350℃ at 12-15℃ / min and hold for 40 minutes, then heat to 650-670℃ at 10℃ / min and hold for 50-70 minutes, and finally cool to 640-650℃ at 6-8℃ / min before pouring; When the degradable metal is ≥99.9 wt% pure zinc: heat to 200℃ at 15-20℃ / min and hold for 20 minutes, then heat to 450-460℃ at 10-12℃ / min and hold for 30-40 minutes, and finally cool to 430-440℃ at 8-10℃ / min before pouring; When the biodegradable metal is a medical-grade zinc alloy: heat to 250℃ at 12-15℃ / min and hold for 30 minutes, then heat to 480-500℃ at 9-11℃ / min and hold for 40-50 minutes, and finally cool to 450-460℃ at 7-9℃ / min before pouring.

6. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: The inert gas in S5 is either argon or helium.

7. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: The controlled environment in S6 meets the requirements of controllable ambient temperature, no dust pollution, inert atmosphere, oxygen volume content ≤0.1%, and the inert atmosphere is either argon or helium.

8. The method for preparing biodegradable metal mesh based on 3D printed molds according to claim 1, characterized in that: In S7, cutting is performed using laser cutting or wire cutting, resulting in a smooth, burr-free cut with a dimensional error of ≤±0.1mm; grinding is done using sandpaper or grinding wheels in stages to remove surface defects; polishing is done using mechanical polishing or chemical polishing to achieve a surface roughness Ra≤0.8μm; cleaning is performed sequentially using ultrasonic cleaning with organic solvents or ultrasonic cleaning with deionized water to remove surface impurities; disinfection is performed using high-temperature steam sterilization at 121℃ and 0.1MPa for 15-30 minutes.

9. The method for preparing a biodegradable metal mesh based on a 3D printed mold according to any one of claims 1 to 8, characterized in that: The thickness of the membrane body is 0.3-2 mm.

10. The method for preparing a biodegradable metal mesh based on a 3D printed mold according to claim 9, characterized in that: The biodegradable metal is ultra-high purity magnesium or medical-grade magnesium alloy or pure zinc or medical-grade zinc alloy with a content of not less than 99.9 wt%.

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