High-simulation rock manufacturing method based on binder spraying 3D printing technology

Abstract

The invention belongs to the technical field of additive manufacturing and rock engineering, and relates to a high-simulation rock manufacturing method based on a binder spraying 3D printing technology, which comprises the following steps: step 1, selecting multi-particle-size silicon dioxide particles, and mixing the silicon dioxide particles with different particle sizes according to a Dinger-Funk particle size grading formula to form a mixture; 2, a calcium-based binder is added into the mixture, and composite powder is formed through ball milling and mixing; 3, the composite powder serves as a powder laying raw material, binder spraying 3D printing equipment is used for laying powder layer by layer according to the specified layer thickness, deionized water is sprayed after powder laying of each layer is completed to trigger a hydration reaction, and 3D printing is completed; and step 4, after 3D printing is completed, maintaining for 26-30 days in an environment with the relative humidity of 80%-95% to obtain the high-simulation rock. According to the method, a silicon dioxide-calcium-based binder material system is innovatively combined, the high-simulation rock is successfully prepared, and the problems that a traditional rock sample is complex in structure, high in heterogeneity, non-repeatable and the like are effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of additive manufacturing and rock engineering, and relates to a method for producing high-simulation rocks based on binder jet 3D printing technology. Background Art

[0002] In many fields such as geological science, engineering practice, and education and teaching, natural rock samples occupy a vital position and are indispensable basic materials for conducting various types of research, teaching demonstrations, and engineering design verification. However, natural rocks are affected by many complex factors in their natural formation process, and have complex structures, strong heterogeneity, and non-repeatability. These characteristics cause researchers, educators, and engineers to face many insurmountable difficulties when using natural rock samples for research, teaching, or design work, which greatly limits the in-depth development and precise implementation of related work. Traditional rock collection and processing methods not only require a lot of manpower, material resources, and time costs, but also easily cause waste of resources and damage to the surrounding ecological environment throughout the process. What's more tricky is that once natural rock samples are damaged during mechanical tests, they cannot be restored to their original state. This irreversible damage seriously restricts the conduct of repeated tests and comparative studies, making it difficult for researchers to obtain comprehensive, accurate, and repeatable experimental data.

[0003] With the rapid development of additive manufacturing technology, binder jetting (BJ) 3D printing technology has emerged. With its unique advantages, such as the ability to manufacture objects with complex structures, no need for mold making, and precise control of porosity, this technology provides a new idea and feasible technical path for building highly realistic rock models. Through this technology, it is expected to produce artificial samples that are highly similar to natural rocks in structure, thereby meeting the diverse needs of rock samples in scientific research, teaching, and engineering design. However, at present, there are still some problems that need to be solved in the existing 3D rock printing methods. For example, the porosity distribution of the printed rock model is uneven, resulting in poor stability of its internal structure; the lack of density affects the strength and durability of the model; the unstable mechanical properties make it difficult to meet the strict requirements for model accuracy and reliability in practical applications.

[0004] In view of the above situation, in order to effectively solve the difficulties in obtaining natural rock samples and the shortcomings of existing 3D printing rock methods, a new material system and printing process combination is urgently needed. Through this innovative combination method, artificial samples with highly consistent structure and performance with natural rocks can be prepared, providing more high-quality, efficient and reliable material support for geological science research, engineering practice and education and teaching. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a method for manufacturing highly realistic rocks based on binder jetting 3D printing technology to solve the problems raised in the background art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for manufacturing highly realistic rocks based on binder jetting 3D printing technology, comprising the following steps: Step 1: Select multi-sized silica particles and mix silica particles of different sizes according to the Dinger-Funk particle size grading formula to form a mixture; Step 2: Add a calcium-based binder to the mixture and form a composite powder through ball milling and mixing; Step 3: Use the composite powder as the powder spreading raw material, and use a binder jetting 3D printing device to spread the powder layer by layer according to the specified layer thickness, and spray deionized water after each layer of powder spreading is completed to trigger the hydration reaction to complete 3D printing; Step 4: After 3D printing is completed, cure for 26 - 30 days in an environment with a relative humidity of 80% - 95% to obtain highly realistic rocks.

[0007] Further, the Dinger-Funk particle size grading formula is:

[0008] where, is the set particle size, D is the largest particle size among the multi-sized silica particles, is the smallest particle size among the multi-sized silica particles, is the model parameter, taking values between 0.21 - 0.37, is the mass fraction of silica particles with a particle size smaller than .

[0009] Further, the mass ratio of the calcium-based binder is 15 - 25% of the composite powder.

[0010] Further, the calcium-based binder is K600 ultra-fine silicate cement.

[0011] Further, the nozzle resolution of the binder jetting 3D printing device is 600 DPI, the number of nozzles is 1280, deionized water is sprayed using a two-way inkjet method, and the ink droplet volume per spray point is 7.0 pl / each; The powder is spread and compacted using a roller rotating counterclockwise, and the roller speed is 100 RPM.

[0012] Further, in Step 3, the specified layer thickness is 90 - 110 um, and the inkjet ratio is controlled at 1:1.08.

[0013] Further, in step 3, a 3D model is designed using 3D design software and imported into a binder jet 3D printing device for 3D printing.

[0014] Further, in step 4, after 3D printing is completed, it is cured in an environment with 90% relative humidity for 28 days to obtain a highly simulated rock.

[0015] The beneficial effects of the present invention are as follows: 1. Based on the binder jet 3D printing technology, the present invention innovatively combines a silica-calcium-based binder material system to successfully prepare a highly simulated rock, effectively solving the problems of complex structure, strong heterogeneity, and non-repeatability of traditional rock samples. By optimizing the Dinger-Funk particle size grading of silica particles and selecting K600 ultrafine Portland cement as the binder, combined with precise printing parameters (such as a layer thickness of 100 μm and an inkjet ratio of 1:1.08), a uniform and dense simulated rock is prepared. This unique combination of materials and processes not only significantly improves the physical structure similarity between the sample and natural rock but also guarantees the stability of its mechanical properties, demonstrating technological innovation.

[0016] 2. The simulated rock prepared by this technology has a high density, a controllable pore structure, and excellent mechanical properties. The 28-day compressive strength reaches 3.56 MPa, the porosity is 36.7%, and the failure mode is highly consistent with that of natural sandstone. It can be widely used to replace natural rock in scientific research, teaching, and engineering simulation. Compared with traditional methods, this solution significantly reduces the preparation cost and cycle and avoids the environmental impact of resource exploitation. In addition, the flexibility of 3D printing technology allows for customization of complex structures according to requirements, meeting the actual application needs of diverse experimental and engineering scenarios. This efficient and low-cost preparation method fully demonstrates its practicality and promotion potential.

[0017] 3. By systematically optimizing the particle size grading, printing parameters, and curing conditions, this solution significantly improves the production efficiency while enhancing the sample quality. The use of two-way inkjet and counterclockwise rotating roller powder spreading and compaction technologies improves the printing efficiency. Combined with 28-day curing at 90% relative humidity, the binder is fully hydrated, and the sample strength gradually increases (1.61 MPa at 7 days, 1.94 MPa at 14 days, and 3.56 MPa at 28 days), showing a stable performance evolution. These optimization measures ensure the uniformity and reliability of the sample, laying a foundation for large-scale and efficient production and further strengthening the practical value of the technical solution.

[0018] Other advantages, objectives and features of the present invention will be set forth to some extent in the following description, and to some extent, will be apparent to those skilled in the art based on the study of the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. Brief Description of the Drawings

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where: Figure 1 is the particle size distribution curve of three different particle sizes of silica in the embodiment and the closest packing; Figure 2 is the structural sample diagram of the highly simulated rock with a cylindrical or cubic shape after 28 days of curing in the embodiment; Figure 3 is the schematic diagram of two failure modes of the highly simulated rock in the embodiment; Figure 4 is the schematic diagram of two failure modes of natural sandstone in the embodiment; Figure 5 is the micro-structure of the highly simulated rock under SEM in the embodiment; Figure 6 is the micro-structure of the highly simulated rock under micro-CT in the embodiment; Figure 7 is the stress-strain curve of the highly simulated rock cured to the 7th day, 14th day, and 28th day in the embodiment. Detailed Embodiments

[0020] The following illustrates the embodiments of the present invention through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention schematically. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0021] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and cannot be understood as a limitation to the present invention; for better illustrating the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual products; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0022] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation of the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0023] Example 1 This embodiment provides a method for fabricating a highly realistic rock based on binder jetting 3D printing technology. The specific steps are as follows: Step 1: Select and mix multi-sized silica particles Select three types of silica particles with maximum particle sizes of 26μm, 44μm, and 104μm respectively, and mix them according to the Dinger-Funk particle size grading formula to achieve the closest packing of the particles. The Dinger-Funk particle size grading formula is:

[0024] Wherein, is the set particle size, D is the maximum particle size among the multi-sized silica particles, which is 104μm in this embodiment, is the minimum particle size among the multi-sized silica particles, which is 26μm in this embodiment, is the model parameter, taking a value between 0.21 - 0.37, and taking 0.37 in this embodiment, is for particle sizes less than is the mass fraction of the silica particles.

[0025] As Figure 1 shown, it is the particle size distribution curve of the three different-sized silica particles and the closest packing. Through EDEM simulation to optimize the particle size grading, combined with the above formula, the mass ratios of the three-sized silica particles are calculated as follows: the silica particles with a maximum particle size of 26μm account for 20%, the silica particles with a maximum particle size of 44μm account for 28%, and the silica particles with a maximum particle size of 104μm account for 42%. Place these particles in a mixing device (ball mill) and stir evenly to form a mixture.

[0026] Step 2: Add a calcium-based binder and mix Add a calcium-based binder to the mixture obtained in Step 1. The calcium-based binder is K600 ultrafine silicate cement, and its mass ratio is 20% of the composite powder. Specifically, take 1000 g of the mixture and add 250 g of K600 ultrafine silicate cement (mass ratio of 20%). Mix them in a ball mill for 4 hours at a rotational speed of 200 RPM to ensure the formation of a uniform composite powder.

[0027] Step 3: 3D printing Use the composite powder obtained in Step 2 as the powder spreading raw material and print it using a binder jet 3D printing device. The device used is a BJ3D printing device (binder jet 3D printing device), with a nozzle resolution of 600 DPI, 1280 nozzles, and a bi-directional inkjet method. The ink droplet volume is 7.0 pl / drop. When spreading the powder, use a roller rotating counterclockwise to compact the powder at a roller speed of 100 RPM.

[0028] The printing parameters are set as follows: layer thickness 100 μm, inkjet ratio controlled at 1:1.08 (i.e., the ratio of deionized water injection volume to powder volume), and inkjet volume 60 μl / mm 2 . As Figure 2 shown, use SolidWorks software to design a cube sample model with a side length of 50 mm and a height of 115 mm, and import the model into the printing device. During the printing process, after spreading the powder for each layer, the nozzle sprays deionized water to trigger the hydration reaction of the calcium-based binder. A total of 1150 layers are printed, with a total forming height of 115 mm.

[0029] Step 4: Curing After printing is completed, remove the sample from the printing platform and place it in a curing box with a relative humidity of 90% for 28 days. During the curing period, the sample gradually solidifies and finally forms a highly simulated rock with a natural rock structure and mechanical properties.

[0030] As Figures 3 to 7 shown, after testing, the micro-CT analysis of the sample microstructure shows that the porosity of the highly simulated rock is 36.7%, the average uniaxial compressive strength after 28 days is 3.56 MPa, and the failure mode mainly shows axial splitting and longitudinal shear, which is similar to the characteristics of natural sandstone.

[0031] Furthermore, as Figure 7 shown, the average uniaxial compressive strengths of the 3D printed samples at 7 days, 14 days, and 28 days are 1.61 MPa, 1.94 MPa, and 3.56 MPa, respectively. The stress-strain curve of the printed sample after 28 days has a high similarity to that of natural sandstone, while at 7 days and 14 days of curing, its curve shows a bimodal behavior, similar to that of some natural limestone and sandstone.

[0032] Example 2 This embodiment provides another method for fabricating a highly realistic rock based on binder jetting 3D printing technology. Compared with Embodiment 1, some parameters are adjusted, and the specific steps are as follows: Step 1: Select and mix multi-sized silica particles Select three types of silica particles with maximum particle sizes of 30 μm, 50 μm, and 100 μm respectively, and mix them according to the Dinger-Funk particle size grading formula, which is the same as that in Embodiment 1. Among them, Among them, is the set particle size, D is the largest particle size among the multi-sized silica particles, which is 100 μm in this embodiment, is the smallest particle size among the multi-sized silica particles, which is 30 μm in this embodiment, is the model parameter, taking 0.37, is less than of the mass fraction of silica particles.

[0033] According to the above formula, the mass ratios of the three-sized silica particles are calculated as follows: the silica particles with a maximum particle size of 30 μm account for 21%, the silica particles with a maximum particle size of 50 μm account for 41%, and the silica particles with a maximum particle size of 100 μm account for 38%. Place these particles in a mixing device (ball mill) and stir well to form a mixture.

[0034] Step 2: Add a calcium-based binder and mix Add K600 ultrafine silicate cement as a calcium-based binder to the mixture obtained in Step 1, and its mass ratio is 18%. Specifically, take 1000 g of the mixture, add 220 g of K600 ultrafine silicate cement, and mix for 3 hours through a ball mill at a rotation speed of 180 RPM to form a uniform composite powder.

[0035] Step 3: 3D printing Use the same binder jetting 3D printing equipment as in Embodiment 1, with a nozzle resolution of 600 DPI, 1280 nozzles, an ink dot volume of 7.0 pl / dot, and a powder spreading roller speed of 100 RPM. Adjust the printing layer thickness to 90 μm, and the inkjet ratio is still 1:1.08. Use SolidWorks to design a cylindrical sample model with a diameter of 50 mm and a height of 115 mm, and import the model into the printing equipment. During the printing process, after each layer of powder spreading, the nozzle sprays deionized water to trigger the hydration reaction of the calcium-based binder. A total of 1150 layers are printed, and the total forming height is 115 mm.

[0036] Step 4: Curing After printing, place the sample in an environment with a relative humidity of 85% for 26 days of curing. After curing, the sample solidifies to form a highly simulated rock.

[0037] After testing, the porosity of the highly simulated rock is 38.2%, and the average uniaxial compressive strength after 28 days is 3.20 MPa. Its mechanical properties are similar to those of natural rocks.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for fabricating a highly realistic rock based on binder jetting 3D printing technology, characterized in that, It includes the following steps: Step 1: Select silica particles with multiple particle sizes, and mix the silica particles with different particle sizes according to the Dinger-Funk particle size grading formula to form a mixture; Step 2: Add a calcium-based binder to the mixture and form a composite powder through ball milling and mixing; Step 3: Use the composite powder as the powder spreading raw material, and use a binder jet 3D printing device to spread the powder layer by layer according to the specified layer thickness, and spray deionized water after each layer of powder spreading is completed to trigger the hydration reaction to complete 3D printing; Step 4: After 3D printing is completed, cure it in an environment with a relative humidity of 80% - 95% for 26 - 30 days to obtain a highly simulated rock.

2. The method for manufacturing a highly realistic rock according to claim 1, characterized in that: The Dinger-Funk particle size grading formula is: where d is the set particle size, D is the largest particle size in the multi-particle-size silica particles, d0 is the smallest particle size in the multi-particle-size silica particles, q is a model parameter, taking values between 0.21 - 0.37, and CPET is the mass fraction of silica particles with a particle size smaller than d.

3. The method for manufacturing a highly realistic rock according to claim 1, wherein: The mass ratio of the calcium-based binder is 15% - 25% of the composite powder.

4. The method for manufacturing highly realistic rocks according to claim 3, characterized in that: The calcium-based binder is K600 ultra-fine silicate cement.

5. The method for manufacturing a highly realistic rock according to claim 1, wherein: The nozzle resolution of the binder jet 3D printing device is 600 DPI, the number of nozzles is 1280, the deionized water is sprayed in a bi-directional inkjet manner, and the ink volume per spray point is 7.0 pl / each; The powder is compacted by a roller rotating counterclockwise, and the roller speed is 100 RPM.

6. The method for manufacturing a highly realistic rock according to claim 5, wherein: In Step 3, the specified layer thickness is 90 - 110 um, and the inkjet ratio is controlled at 1:1.

08.

7. The method for manufacturing a highly realistic rock according to claim 1, characterized in that: In Step 3, a 3D model is designed using 3D design software and imported into the binder jet 3D printing device for 3D printing.

8. The method for manufacturing a highly realistic rock according to claim 1, characterized in that: In Step 4, after 3D printing is completed, cure it in an environment with a relative humidity of 90% for 28 days to obtain a highly simulated rock.

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