Multi-layer structure seed planting ball for desertification control based on additive manufacturing

Abstract

The invention provides a multilayer structure seed planting ball for desertification control based on additive manufacturing, and relates to the technical field of ecological restoration engineering, the planting ball adopts a five-layer composite structure design: the outer layer is a gradient microporous wind erosion resistant layer (the porosity is 65% + / -5%) made of a PLA material; a large-through-hole oxygen exchange layer (the compressive strength is larger than or equal to 8 MPa) with a PLA / straw fiber reinforced framework is arranged on the middle layer, a water storage layer (the volume ratio is 40%-60%) with conical interconnected cavities is constructed on the inner layer, water-absorbent resin (the water absorption rate is larger than or equal to 300 g / g) is arranged in the inner layer, and seeds and gibberellin sustained-release microspheres are loaded in a sphere center bin (the sustained-release period is 20-30 days). The hydromechanics optimization structure is innovatively integrated, moisture gradient regulation and control are achieved through the conical cavity and the through holes between the grooves, the humidity sensor embedded through the digital twin technology is matched, and the single-time rainfall utilization rate is increased to 75% or above. The method is especially suitable for ecological restoration engineering of arid areas with annual precipitation below 200mm.

Description

Technical Field

[0001] The present invention belongs to the technical field of ecological restoration engineering, and more specifically, relates to a multi-layered seed planting ball for desertification control based on additive manufacturing. Background Art

[0002] Existing desertification control technologies have the following shortcomings: Insufficient wind erosion resistance: The damage rate of traditional seed coatings in strong wind environments is as high as 30%-40% (data source: Journal of Arid Land Ecology, 2023), resulting in seed exposure and failure; Low water utilization efficiency: Existing devices lack gradient water storage design, and the utilization rate of a single precipitation is less than 40%; Material degradation mismatch: PLA material degradation rate is faster than the seed germination cycle (e.g. PLA degradation rate is 0.3mm / month, while seeds take 30 days to germinate), resulting in oxygen supply interruption; Lack of monitoring methods: Without real-time humidity monitoring, planting strategies cannot be adjusted dynamically.

[0003] This invention uses a five-layer composite structure design that integrates gradient micropore anti-wind erosion, large through-pore oxygen exchange, and conical water storage and slow-release control functions. Combined with digital twin technology, it achieves the following breakthroughs: The porosity of the wind erosion-resistant layer is gradient, and the damage rate is reduced to ≤10% in a windy and sandy environment; The capillary pump effect of the conical aquifer increases the utilization rate of precipitation to 75%; The PLA degradation rate accurately matches the seed germination period (error ± 3 days); The Internet of Things provides real-time monitoring and supports precise ecological restoration. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a multi-layer seed planting ball for desertification control based on additive manufacturing to solve the above problems.

[0005] A multi-layer composite structure desertification control seed planting ball, comprising: Gradient microporous anti-wind erosion layer, made of PLA / PCL copolymer by 3D printing, with a porosity of 65%±5%, a pore size gradient distribution of 0.2-0.5mm, and a porosity gradient difference ≥15%; Large through-hole oxygen exchange layer, located inside the anti-wind erosion layer, with a through-hole diameter of 2-5mm, built-in PLA / straw fiber reinforced skeleton, and compressive strength ≥8MPa; The conical aquifer consists of interconnected cavities with 3-5 levels of tapered changes. The cavity wall is equipped with a diversion groove, which accounts for 40%-60% of the volume and is pre-buried with polyacrylic acid absorbent resin with a water absorption rate of ≥300g / g. Through holes between the slots connect the various layers of the structure and realize the coordinated transmission of water, air and nutrients through bionic channels; The core chamber has a diameter of 8-15mm and contains seeds and gibberellin / chitosan composite sustained-release microspheres with a sustained-release period of 20-30 days. It is also equipped with a pH buffer (calcium carbonate / trisodium citrate composite particles).

[0006] Preferably, the gradient microporous anti-wind erosion layer uses a PLA / PCL copolymer with a degradation rate of 0.05-0.2 mm / month (pH = 6.8 ± 0.2), and is matched with the pH buffer of the spherical center chamber to achieve synchronous control of the degradation rate and the seed germination cycle. The large-pore oxygen exchange layer forms a honeycomb structure by reinforcing the PLA skeleton with straw fiber, with a porosity of ≥50% and an oxygen permeability of ≥0.3 mL / (cm²·h). The guide grooves of the conical water storage layer and the water-absorbing resin synergistically form a capillary pump effect, which increases the utilization rate of single precipitation to more than 75%. A 2×2×5 mm sensor slot is reserved at the top of the cavity for implanting a humidity sensor. The gibberellin / chitosan composite microspheres of the spherical center chamber are prepared by an electrospinning process, with a microsphere particle size of 50-200 μm and an encapsulation rate of ≥90%. The through holes between the grooves adopt a spiral fluid channel design, combined with ANSYS Fluent fluid mechanics optimization, and the wind resistance coefficient is ≤0.15, effectively reducing the risk of wind and sand accumulation.

[0007] A method for preparing a multi-layer composite structure desertification control seed planting ball comprises the following steps: Using fused deposition modeling (FDM) 3D printing technology, a gradient microporous anti-wind erosion layer and a large through-hole oxygen exchange layer are constructed layer by layer; During the printing process, a pause layer is preset (G code M600 / M25 command) to artificially embed water-absorbing resin and seed-release microspheres; Using digital twin technology to simulate the fluid dynamics of conical aquifers, the inclination angle of the diversion channel (15°-30°) and the taper ratio of the cavity (1:3-1:5) were optimized. A humidity sensor was implanted, and the soil moisture and degradation process were monitored in real time through an Internet of Things (IoT) module. The 3D printing parameters were set as follows: nozzle temperature 190-210°C, layer thickness 0.1-0.3mm, filling density 60-80%, and printing speed 30-50mm / s.

[0008] A digital twin-based desertification control system includes: a cloud-based data analysis platform that receives humidity sensor data and generates a soil moisture heat map; a drone cluster that dynamically adjusts the density and position of planting bulbs based on the heat map, with a coverage accuracy of ±0.5m. The drones are equipped with multispectral cameras, which use AI algorithms to identify surface vegetation coverage and provide feedback to the cloud platform to optimize planting strategies.

[0009] Compared with the prior art, the present invention has the following beneficial effects: Wind erosion resistance: Gradient microporous structure reduces wind resistance, breakage rate ≤10% (traditional 30%-40%); Water utilization: The capillary pump effect of the conical aquifer enables the utilization rate of precipitation to reach 75% (traditional 40%); Degradation synchronization: PLA degradation rate error is ±3 days, ensuring oxygen supply for seed germination; Intelligent management and control: Digital twin + drone system will increase planting efficiency by 50% and reduce costs by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a cross-sectional view of the three-dimensional layered structure of the planting ball of the present invention; Figure 2 This is a schematic diagram of the structure of the large through-hole oxygen exchange layer of the present invention; Figure 3 This is a diagram showing the degradation of PLA in soil according to the present invention (30d); Figure 4 This is a wind tunnel test diagram of the planting ball of the present invention.

[0011] In the figure, the correspondence between the component names and the drawing numbers is: 1. Gradient microporous anti-wind erosion layer; 2. Large through-pore oxygen exchange layer; 3. Conical water storage layer; 4. Spherical center warehouse. DETAILED DESCRIPTION

[0012] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0013] See also Figures 1-4 The present invention provides a multi-layer composite structure desertification control seed planting ball, comprising: Gradient microporous anti-wind erosion layer 1, formed by 3D printing of PLA / PCL copolymer, with a porosity of 65%±5%, a pore size gradient distribution of 0.2-0.5mm, and a porosity gradient difference ≥15%; Large through-hole oxygen exchange layer 2, located inside the anti-wind erosion layer, with a through-hole diameter of 2-5mm, a built-in PLA / straw fiber reinforced skeleton, and a compressive strength of ≥8MPa; The conical water storage layer 3 comprises interconnected cavities with 3-5 levels of tapered changes, with diversion grooves set on the cavity walls, accounting for 40%-60% of the volume, and pre-buried polyacrylic acid absorbent resin with a water absorption rate of ≥300g / g; Through holes between the slots connect the various layers of the structure and realize the coordinated transmission of water, air and nutrients through bionic channels; The core chamber 4 has a diameter of 8-15 mm and contains seeds and gibberellin / chitosan composite sustained-release microspheres with a sustained-release period of 20-30 days. A pH buffer (calcium carbonate / trisodium citrate composite particles) is also configured simultaneously.

[0014] The gradient microporous anti-erosion layer utilizes a PLA / PCL copolymer with a degradation rate of 0.05-0.2 mm / month (pH = 6.8 ± 0.2). This layer matches the pH buffer in the core chamber, enabling synchronized control of the degradation rate and seed germination cycle. The large-pore oxygen exchange layer utilizes a straw fiber-reinforced PLA skeleton to form a honeycomb structure with a porosity of ≥50% and an oxygen permeability of ≥0.3 mL / (cm²·h). The conical aquifer's diversion grooves and water-absorbing resin synergistically create a capillary pump effect, increasing the utilization rate of single-time precipitation to over 75%. A 2×2×5 mm sensor slot is reserved at the top of the cavity for the implantation of a humidity sensor. The gibberellin / chitosan composite microspheres in the core chamber are produced via electrospinning, with a particle size of 50-200 μm and an encapsulation efficiency of ≥90%. The inter-groove through-holes utilize a spiral fluid channel design, optimized with ANSYS Fluent fluid dynamics, resulting in a drag coefficient of ≤0.15, effectively reducing the risk of wind-blown sand accumulation.

[0015] A method for preparing a multi-layer composite structure desertification control seed planting ball comprises the following steps: Using fused deposition modeling (FDM) 3D printing technology, a gradient microporous anti-wind erosion layer and a large through-hole oxygen exchange layer are constructed layer by layer; During the printing process, a pause layer is preset (G code M600 / M25 command) to artificially embed water-absorbing resin and seed-release microspheres; Using digital twin technology to simulate the fluid dynamics of conical aquifers, the inclination angle of the diversion channel (15°-30°) and the taper ratio of the cavity (1:3-1:5) were optimized. A humidity sensor was implanted, and the soil moisture and degradation process were monitored in real time through the Internet of Things (IoT) module. The 3D printing parameters were set as follows: nozzle temperature 190-210°C, layer thickness 0.1-0.3mm, filling density 60-80%, and printing speed 30-50mm / s.

[0016] A desertification control system based on digital twins includes: a cloud-based data analysis platform that receives humidity sensor data and generates a soil moisture heat map; a drone cluster that dynamically adjusts the density and position of planting bulbs based on the heat map, with a coverage accuracy of ±0.5m. The drones are equipped with multispectral cameras, which use AI algorithms to identify surface vegetation coverage and provide feedback to the cloud platform to optimize planting strategies.

[0017] Working principle: Use the 3D printer to set the G-code parameters in advance, and set a pause layer at the pre-embedded point, such as: Print Settings → Custom G-code → Layer Change. Enter the G-code for the specified layer, such as M600 or M25. Some software can set the pause layer manually, which will cause the printer to pause at the preset point. At the same time, manually inserting a pre-prepared seed structure, water-absorbing resin, or some digital twin technology insertion can be achieved by modifying the structure.

[0018] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A multi-layer composite structure desertification control seed planting ball, characterized in that: include: Gradient microporous anti-wind erosion layer, made of PLA / PCL copolymer by 3D printing, with a porosity of 65%±5%, a pore size gradient distribution of 0.2-0.5mm, and a porosity gradient difference ≥15%; Large through-hole oxygen exchange layer, located inside the anti-wind erosion layer, with a through-hole diameter of 2-5mm, built-in PLA / straw fiber reinforced skeleton, and compressive strength ≥8MPa; The conical aquifer consists of interconnected cavities with 3-5 levels of tapered changes. The cavity wall is equipped with a diversion groove, which accounts for 40%-60% of the volume and is pre-buried with polyacrylic acid absorbent resin with a water absorption rate of ≥300g / g. Through holes between the slots connect the various layers of the structure and realize the coordinated transmission of water, air and nutrients through bionic channels; The core chamber has a diameter of 8-15mm and contains seeds and gibberellin / chitosan composite sustained-release microspheres with a sustained-release period of 20-30 days. It is also equipped with a pH buffer (calcium carbonate / trisodium citrate composite particles).

2. The multi-layer composite structure desertification control seed planting ball according to claim 1, characterized in that: The gradient microporous anti-wind erosion layer uses PLA / PCL copolymer with a degradation rate of 0.05-0.2 mm / month (pH=6.8±0.2), and is matched with the pH buffer of the spherical center chamber to achieve synchronous control of the degradation rate and the seed germination cycle.

3. The multi-layer composite structure desertification control seed planting ball according to claim 1, characterized in that: The large-pore oxygen exchange layer is formed into a honeycomb structure by reinforcing the PLA skeleton with straw fibers, with a porosity of ≥50% and an oxygen permeability of ≥0.3mL / (cm²·h).

4. The multi-layer composite structure desertification control seed planting ball according to claim 1, characterized in that: The diversion groove of the conical water storage layer and the water-absorbing resin work together to form a capillary pump effect, which increases the utilization rate of single precipitation to more than 75%. A 2×2×5mm sensor slot is reserved at the top of the cavity for implanting a humidity sensor.

5. The multi-layer composite structure desertification control seed planting ball according to claim 1, characterized in that: The gibberellin / chitosan composite microspheres in the spherical core are prepared by an electrostatic spinning process, the microsphere particle size is 50-200 μm, and the encapsulation rate is ≥90%.

6. The multi-layer composite structure desertification control seed planting ball according to claim 1, characterized in that: The inter-slot through holes adopt a spiral fluid channel design, combined with ANSYS Fluent fluid mechanics optimization, with a drag coefficient of ≤0.15, effectively reducing the risk of wind and sand accumulation.

7. A method for preparing a multi-layer composite structure desertification control seed planting ball, characterized in that , including the following steps: Using fused deposition modeling (FDM) 3D printing technology, a gradient microporous anti-wind erosion layer and a large through-hole oxygen exchange layer are constructed layer by layer; During the printing process, a pause layer is preset (G code M600 / M25 command) to artificially embed water-absorbing resin and seed-release microspheres; Using digital twin technology to simulate the fluid dynamics of conical aquifers, the inclination angle of the diversion channel (15°-30°) and the taper ratio of the cavity (1:3-1:5) were optimized. Humidity sensors are implanted and the soil moisture and degradation process are monitored in real time through the Internet of Things (IoT) module.

8. The method for preparing a multi-layer composite structure desertification control seed planting ball according to claim 7, characterized in that: The 3D printing parameters were set as follows: nozzle temperature 190-210°C, layer thickness 0.1-0.3 mm, filling density 60-80%, and printing speed 30-50 mm / s.

9. A desertification control system based on digital twins, characterized by: include: The seed planting ball according to any one of claims 1 to 6; A cloud-based data analysis platform receives moisture sensor data and generates a soil moisture thermal map; The drone cluster dynamically adjusts the density and position of bulbs based on the heat map, with a coverage accuracy of ±0.5m.

10. The desertification control system based on digital twins according to claim 9, characterized in that: The drone is equipped with a multispectral camera, which uses AI algorithms to identify surface vegetation coverage and feeds back to the cloud platform to optimize planting strategies.

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