Multi-orientation microfiber 3D printing method and application

Abstract

The application discloses a kind of multi-orientation microfiber 3D printing method, the target structure is sliced, and slice layer is obtained;Obtain the orientation of target fiber silk in each slice layer;Collect fiber silk, and the collected fiber silk is arranged side by side along the third direction;Each slice layer in target structure is printed on the printing platform layer by layer using the fiber silk arranged along the third direction;According to the orientation of target fiber silk in the slice layer being printed, adjust the direction of printing platform, so that the orientation of fiber silk arranged along the third direction is consistent with the orientation of target fiber silk in the slice layer being printed on the printing platform, and the fiber silk is transferred to the printing platform.The application provides a kind of multi-orientation microfiber 3D printing method, and the target structure of printing with greater thickness or height can be printed.

Description

Technical Field

[0001] This invention relates to the fields of additive manufacturing and 3D printing technology, and in particular to a multi-orientation microfiber 3D printing method and its application. Background Technology

[0002] Current 3D printing technologies, primarily including Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and Stereolithography (SLA), have become essential tools for manufacturing various products and prototypes. However, traditional 3D printing technologies face significant limitations in fabricating microfibers, particularly at the nanometer to micrometer scale. Microfibers are commonly used in various applications such as filtration, tissue engineering, sensors, and protective clothing, especially in supporting cell growth and the creation of tissue engineering scaffolds. However, traditional 3D printing technologies, particularly FDM, suffer from reduced nutrient transport efficiency and hinder the formation of continuous cell networks due to macroscopic porosity caused by their low resolution. Similarly, Selective Laser Sintering (SLS) and Stereolithography (SLA) also struggle to produce microfibers due to their inherent resolution and material limitations, which can be a limiting factor in applications requiring high precision and specific functionalities. In short, traditional 3D printing technologies are insufficient for microfiber printing requirements.

[0003] Near-field direct writing (NFDW) is a technique capable of generating nanoscale to microscale structures. NFDW boasts extremely high resolution and can produce intricate microfiber structures. However, the main problems with NFDW are low efficiency and slow throughput, primarily due to its serial writing method and complex operation. Furthermore, in NFDW printing, the orientation of microfibers is controlled by an electric field connected to the printing platform. As the thickness of the target structure increases and fiber layers accumulate, the control of the electric field on the printing platform for each new layer of microfibers weakens. With increasing layer thickness, the fiber collection efficiency gradually decreases until it reaches approximately 0 mm, with a maximum thickness of 1 mm for most materials. Therefore, directly using fiber filament technology to prepare each layer results in a limited printing thickness. Thus, due to the limitation of the electric field, NFDW faces significant challenges in preparing microfiber structures with large heights or thicknesses. In practical applications, NFDW struggles to meet the demands of large-scale production and high efficiency.

[0004] In summary, microfiber printing technology remains an uncharted territory, fraught with design and fabrication challenges that often prevent the achievement of ideal results. The main problem with current technologies lies in their inability to achieve high-precision, high-efficiency, and large-scale microfiber 3D printing, particularly in multi-angle microfiber printing, where significant technical challenges remain. These issues stem primarily from the limitations of current 3D printing and microfiber printing technologies, lacking a method or apparatus that can integrate the advantages of these technologies while addressing their respective shortcomings. Summary of the Invention

[0005] To overcome at least one of the shortcomings of the prior art, this invention provides a multi-orientation microfiber 3D printing method. Before printing, the fiber direction is controlled to give the fibers a certain orientation. During printing, the fibers with a certain orientation are transferred to the printing platform according to the orientation of the target fiber filaments in the printed slice layer of the target structure. During the transfer of the fiber filaments to the printing platform, the fiber orientation or the direction of the printing platform is directly controlled to make the fiber orientation consistent with the orientation of the target fiber filaments in the printed slice layer. After the two directions are aligned, the fiber filaments are directly transferred to the printing platform without the need to apply an electric field to the printing platform. During the transfer of the fiber filaments to the printing platform, the fiber filaments are not affected by the electric field force, enabling the printing of target structures with large thickness or height.

[0006] The technical solution adopted by this invention to solve its problem is:

[0007] A multi-orientation microfiber 3D printing method

[0008] The target structure is sliced ​​along a first direction to obtain sliced ​​layers; the orientation of the target fibers in each sliced ​​layer is obtained; the first direction is the stacking direction of the target fiber layers of the target structure, and the orientation of the target fibers in the sliced ​​layers is the second direction.

[0009] Collect the fibers and arrange them side by side along a third direction;

[0010] The fiber filaments arranged along the third direction are used to print each slice layer in the target structure onto the printing platform one by one;

[0011] Based on the orientation of the target fiber filament in the slice layer being printed, the orientation of the printing platform is adjusted so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filament in the slice layer being printed on the printing platform, and the fiber filament is transferred to the printing platform.

[0012] After the fiber transfer of each slice is completed, the fiber transfer of the next slice is carried out.

[0013] Based on the aforementioned multi-orientation microfiber 3D printing method, the fiber orientation is controlled before printing to achieve a specific orientation. During printing, the oriented fibers are transferred to the printing platform according to their orientation within the target structure's printed slices. By directly controlling the fiber orientation or the printing platform's direction, the fibers are transferred directly to the platform, eliminating the need to apply an electric field. Since electrostatic discharge is unaffected by the electric field during this transfer, the method can print target structures with significant thickness or height.

[0014] Preferably, the first direction is perpendicular to the slice layer, and the first direction is perpendicular to the second direction; the third direction includes the second direction.

[0015] Preferably, in the third direction, adjacent fibers are parallel or nearly parallel.

[0016] Preferably, within one of the sliced ​​layers, the target fiber filaments are unidirectional.

[0017] Preferably, before the fiber filaments are transferred to the printing platform, the orientation of the fiber filaments arranged along the third direction is maintained according to the orientation of the target fiber filaments in the slice layer being printed. The printing platform is rotated so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filaments in the slice layer being printed on the printing platform.

[0018] The rotation angle of the printing platform is the angle between the orientation of the fibers arranged along the third direction and the second direction, and the rotation direction of the rotating platform is either clockwise or counterclockwise.

[0019] The fibers arranged along the third direction come into direct contact with the printing platform and are transferred onto the printing platform.

[0020] Preferably, the multi-orientation microfiber 3D printing method further includes selective curing, in which the fiber filaments transferred to the printing platform are selectively cured, and the next slice layer is printed after selective curing is completed; the selective curing is photocuring, and the photocuring process is to use a 365nm-405nm laser to cure for 5s-200s.

[0021] Preferably, the multi-orientation microfiber 3D printing method further includes a wetting process, wherein the wetting process involves humidifying the fibers arranged side by side along the third direction for a time of 2-10 seconds.

[0022] Preferably, the process of slicing the target structure along the first direction involves using 3D printing slicing software to obtain data of the target structure, inputting the target structure into the host computer, and using the slicing software to obtain the shape of each slice layer and the second direction of the target fibers in each slice layer.

[0023] Preferably, the multi-orientation microfiber 3D printing method further includes fiber filament recovery. After the last slice layer of the target structure is selectively cured, the fiber structure on the printing platform is immersed in a dissolving solvent, and the uncured fiber filaments are dissolved in the dissolving solvent to obtain the target structure. At the same time, a solution containing dissolved fiber filaments is obtained. The solution is dried and separated to obtain a solid containing fiber filaments.

[0024] In summary, the multi-orientation microfiber 3D printing method provided by this invention has the following technical advantages: it can meet the requirements of microfiber printing and has high printing efficiency. During the printing process, when the fiber filaments are transferred to the printing platform, the fiber filament orientation is not controlled by an electric field, enabling the printing of target structures with large thickness or height.

[0025] This invention also provides an application of a multi-orientation microfiber 3D printing method.

[0026] An application of a multi-orientation microfiber 3D printing method is disclosed, in which the aforementioned multi-orientation microfiber 3D printing method is used to print target structures, including but not limited to medical devices, filtration and separation devices, sensing components, and electronic circuit structures.

[0027] In the fields of tissue engineering and biomedicine, this multi-orientation microfiber 3D printing method can be used to print medical devices, such as bio-scaffolds or biocompatible scaffolds with complex structures. The fabricated bio-scaffolds or biocompatible scaffolds can mimic the microenvironment of natural tissues, supporting cell growth and tissue regeneration. During the printing process, by precisely controlling the orientation of microfibers within each slice layer, the structural arrangement of natural tissues can be imitated, such as the fiber arrangement of muscle tissue or the specific orientation of heart tissue. This is crucial for directed cell growth and the formation of functional tissues. Furthermore, the multi-orientation microfiber structure in medical devices helps improve nutrient and oxygen transport, accelerating the tissue repair process.

[0028] In the field of filtration and separation technology, this multi-oriented microfiber 3D printing method can be used to print filtration and separation devices, such as high-efficiency filter materials. These filter materials can capture particulate matter and microorganisms at the nanoscale. By adjusting the orientation and layout of the microfibers within the filter material, filter media with specific porosity and pore size distributions can be designed, thereby optimizing fluid flow and filtration efficiency and achieving effective capture of particles of different sizes. This filtration and separation device using multi-oriented microfiber 3D printing is particularly suitable for applications requiring high-precision filtration, such as air purification, water treatment, and healthcare products.

[0029] In the fields of flexible electronics and sensor technology, this multi-orientation microfiber 3D printing method can be used to print sensing components and electronic circuit structures, such as 3D structures with specifically oriented conductive paths. These 3D structures can be used to develop novel flexible electronic devices and highly sensitive sensors. For example, by precisely controlling the arrangement and orientation of conductive microfibers, sensors capable of sensing and responding to mechanical deformation, temperature changes, or the presence of chemical substances can be fabricated. This highly customized microfiber 3D printing technology offers new possibilities for the development of wearable electronic devices, smart fabrics, and environmental monitoring devices. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the printing process of a multi-orientation microfiber 3D printing method according to the present invention.

[0031] Figure 2 This is a schematic diagram of the printing platform adjustment in a multi-orientation microfiber 3D printing method of the present invention.

[0032] Figure 3 This is a schematic diagram of an embodiment of a multi-orientation microfiber 3D printing device according to the technical solution of the present invention.

[0033] Figure 4 for Figure 3 Internal structure diagram.

[0034] Figure 5 for Figure 4 Axonometric drawing.

[0035] Figure 6 This is a schematic diagram showing the positions of the platform conveying device and the fiber orientation and sorting device.

[0036] Figure 7 for Figure 6 The main view.

[0037] Figure 8 This is a schematic diagram showing the direction of movement of the printing platform and the adjustment direction of the fiber conveyor belt during printing.

[0038] Figure 9 This is a schematic diagram of another embodiment of the movement direction of the printing platform and the adjustment direction of the fiber conveyor belt during printing.

[0039] Figure 10 This is a schematic diagram of another embodiment of the movement direction of the printing platform and the adjustment direction of the fiber conveyor belt during printing.

[0040] The meanings of the reference numerals in the attached figures are as follows:

[0041] 10. Collected filaments; 20. Oriented filaments; 30. The part of the target structure that has been printed; 40. Fibers transferred to the printing platform;

[0042] 1. Chassis;

[0043] 2. Host computer;

[0044] 3. Fiber collecting device; 31. Turntable;

[0045] 4. Fiber orientation and straightening device; 41. Fiber conveyor belt; 42. Mounting bracket; 43. Angle adjustment device; 431. Fixed base; 432. Adjustable base; 433. Hinge position; 434. Adjustment assembly;

[0046] 5. Printing platform; 50. Printing surface; 51. Platform orientation adjustment device; 511. Mounting base; 512. Motor;

[0047] 6. Platform conveyor device; 60. Platform conveyor belt; 61. Inclined section; 62. Horizontal section;

[0048] 7. Humidification device; 71. Liquid storage box; 72. Automatic nozzle;

[0049] 8. Selective curing device; 81. Lifting device; 82. Guide column; 83. Lead screw; 84. Drive motor. Detailed Implementation

[0050] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0051] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0053] See Figure 1 and Figure 2 This invention discloses a multi-orientation microfiber 3D printing method.

[0054] A multi-orientation microfiber 3D printing method mainly includes sequential operation or control steps:

[0055] The target structure is sliced ​​along a first direction to obtain sliced ​​layers, and the orientation of the target fibers in each sliced ​​layer is obtained. The first direction is the stacking direction of the target fiber layers of the target structure, and the orientation of the target fibers in the sliced ​​layers is the second direction.

[0056] Collect the fibers and arrange them side by side along a third direction.

[0057] The fiber filaments arranged along a third direction are used to print each slice layer of the target structure onto the printing platform one by one.

[0058] Based on the orientation of the target fiber filaments in the slice layer being printed, the orientation of the printing platform is adjusted so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filaments in the slice layer being printed on the printing platform, and the fiber filaments are transferred to the printing platform.

[0059] After the fiber transfer of each slice is completed, the fiber transfer of the next slice is carried out.

[0060] Based on the above technical solution, the present invention provides a multi-orientation microfiber 3D printing method. During the printing process, the fiber direction is first controlled, and the fibers are arranged side-by-side according to a certain orientation (third direction). This facilitates subsequent adjustment of the orientation of the fibers as needed, or uses the third direction and fiber orientation as a basis and reference for adjusting the printing platform orientation. Then, based on the orientation (second direction) of the target fiber in the currently printed slice layer, the orientation of the fibers arranged along the third direction is adjusted, or the printing platform orientation is adjusted, so that the orientation of the fibers arranged along the third direction matches the orientation of the target fiber in the currently printed slice layer on the printing platform. Next, the fibers arranged side-by-side along the third direction are transferred to the printing platform. After the fibers are transferred to the printing platform, their orientation is the same as the orientation of the target fiber in the currently printed slice layer. The transfer of fibers for the next slice layer is performed only after the fiber transfer of all slice layers is completed.

[0061] During the printing process, based on the orientation (second direction) of the target fiber filaments in the slice layer being printed, the orientation of the fiber filaments arranged along the third direction or the orientation of the printing platform is adjusted so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filaments in the slice layer being printed on the printing platform. This allows the fiber filaments to be directly transferred to the printing platform. During the transfer of the fiber filaments to the printing platform according to the second direction, the fiber filaments do not rely on electric field forces to adjust their orientation, and the adjustment of the printing platform orientation does not rely on electric field forces. Throughout the entire printing process of the target structure, only layer-by-layer stacking of fiber filaments is required. Therefore, in summary, the multi-orientation microfiber 3D printing method of this invention has no limitation on the height of the printed target structure and can achieve target structures with high thickness and large height.

[0062] The printing process in this invention includes orienting the target fiber filaments (second direction) in the slice layer being printed, adjusting the printing platform orientation so that the orientation of the fiber filaments arranged along the third direction matches the orientation of the target fiber filaments in the slice layer being printed on the printing platform. Then, the fiber filaments arranged side-by-side along the third direction are transferred to the printing platform. After the fiber filaments are transferred to the printing platform, their orientation is the same as the orientation of the target fiber filaments in the slice layer being printed. This overcomes the defect in existing microfiber 3D printing technology, where the orientation of microfibers is controlled by an electric field connected to the printing platform. As the thickness of the target structure increases and fiber layers accumulate in the target structure, the control of the electric field on the new layer of microfibers weakens. It also overcomes the problem in existing technology where fiber collection efficiency gradually decreases with increasing layer thickness, leading to limited printing thickness. The target structure thickness in existing microfiber 3D printing technology is around 1 mm, while the multi-orientation microfiber 3D printing method of this invention theoretically allows for unlimited target structure thickness. In actual printing, due to the limitations of the printing equipment itself, the target structure thickness can reach tens of meters.

[0063] In this invention's technical solution, a multi-oriented microfiber 3D printing method, a first direction is perpendicular to the slicing layer, and the first direction is perpendicular to a second direction; the third direction includes the second direction. The first direction is generally the stacking direction of the target fiber filament layers of the target structure, and is generally the thickness or height direction of the target structure. The slicing layer is generally sliced ​​along a horizontal direction, and the slicing layer is generally a horizontal layer.

[0064] In this invention's technical solution, a multi-oriented microfiber 3D printing method, collected fiber filaments are arranged side-by-side along a third direction; and in this third direction, adjacent fiber filaments are parallel or nearly parallel. Since the outer diameter of fiber filaments is generally at the nanometer level (around 100 nm) and the length is at the centimeter level (around 2 cm), meaning the fiber filaments have a very large aspect ratio, ensuring complete alignment between adjacent fiber filaments arranged side-by-side along the third direction is extremely difficult. Furthermore, the fiber filaments transferred to the printing surface do not need to be completely parallel; near-parallel alignment is sufficient. Of course, parallel alignment between adjacent fiber filaments is the optimal state.

[0065] Similarly, since the fibers arranged along the third direction cannot be guaranteed to be completely parallel, the orientation of the printing platform is adjusted so that the orientation of the fibers arranged along the third direction is consistent with the orientation of the target fibers in the slice layer being printed on the printing platform. Of course, it would be better if the orientation of the fibers arranged along the third direction could be parallel to the orientation of the target fibers in the slice layer being printed on the printing platform. However, as mentioned earlier, the fibers have a very large aspect ratio, making it difficult to guarantee that the fibers are completely parallel to each other, and thus difficult to guarantee that the orientation of the fibers arranged along the third direction is completely parallel to the orientation of the target fibers on the printing platform. Therefore, adjusting the orientation of the printing platform so that the orientation of the fibers arranged along the third direction is consistent with the orientation of the target fibers in the slice layer being printed on the printing platform is sufficient to meet the requirements.

[0066] To ensure the performance of the printed target structure, most of the fibers in the third-direction alignment remain parallel, with only a small portion remaining substantially parallel to the parallel fibers. Similarly, the printing platform orientation is adjusted so that the target fibers in the slice being printed on the platform are oriented parallel to the orientation of most of the fibers in the third-direction alignment.

[0067] In the multi-orientation microfiber 3D printing method of the present invention, since the outer diameter of the fiber is generally at the nanometer level, the outer diameter is very small. In the printing of a slice layer, the printing platform generally uses a reciprocating collection method to collect multiple fiber filament layers. This ensures the thickness of the slice layer and improves the printing efficiency. In addition, in a slice layer, there are multiple fiber filaments. Due to the adhesion of the fiber filaments and the weight of the fiber filaments themselves, the fiber layers inside the slice layer are well bonded, which improves the accuracy and stability of the printed target structure.

[0068] In the multi-orientation microfiber 3D printing method of this invention, because the outer diameter of the fiber filaments is generally at the nanometer level, the distance between two adjacent fiber filaments arranged side by side along a third direction may be zero, less than, or greater than the outer diameter of the fiber filaments. Furthermore, the distance between two adjacent fiber filaments arranged side by side along a third direction is not necessarily consistent. In this slice layer printing process, the printing platform uses a reciprocating collection method to collect multiple fiber filament layers. Upper layer fiber filaments fall between two fibers in the lower layer or directly onto the fibers in the lower layer, forming a complete slice layer. This ensures the slice layer thickness and stability. Under macroscopic conditions, the surface of the selectively cured slice layer or the printed target structure is a flat surface. However, because the slice layer is formed by stacking fiber filaments according to a certain orientation, under microscopic conditions, the surface of the slice layer or the printed target structure is a non-flat surface. This non-standard surface determines its application scenarios and fields, such as target structures including but not limited to medical devices, filtration and separation devices, sensing components, and electronic circuit structures.

[0069] In this invention's multi-orientation microfiber 3D printing method, the target fiber filaments are unidirectional within each layer. Firstly, the target structure is sliced ​​along a first direction, resulting in thin slices, typically at the nanometer level (a few hundred nanometers). This ensures that the target fiber filaments are unidirectional within each layer. However, in practical applications, in target structures with centimeter-level heights, if one or a few slices do not have a unidirectional orientation, the non-unidirectional fiber filaments in the original slices can be unidirectionalized during printing without affecting the function and performance of the printed target structure.

[0070] In the multi-orientation microfiber 3D printing method of the present invention, the printing platform is actively adjusted so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filaments in the slice layer being printed on the printing platform. Then, the fiber filaments arranged side by side along the third direction are directly brought into contact with the printing platform and transferred directly onto the printing platform.

[0071] Before the fibers are transferred to the printing platform, the orientation of the fibers arranged along the third direction is maintained according to the orientation of the target fibers in the slice layer being printed. The printing platform rotates to align the orientation of the fibers arranged along the third direction with the orientation of the target fibers in the slice layer being printed. The rotation angle of the printing platform is the angle between the orientation of the fibers arranged along the third direction and the second direction, and the rotation direction of the platform is either clockwise or counterclockwise. The fibers arranged along the third direction directly contact the printing platform and are transferred onto it.

[0072] like Figure 2 As shown, Figure 2 In (a), the fibers are arranged side by side along the third direction. Figure 2 In (b), the rectangular frame represents the printing platform. To facilitate observation of the platform's orientation before and after rotation, the four vertices of the rectangular printing platform are labeled A1, A2, A3, and A4, respectively, and the four sides are labeled Q1, Q2, Q3, and Q4, respectively. The orientation of the target fiber filaments in the slice layer being printed is as follows: Figure 2 (b) Direction of the dashed line, such as Figure 2 The second direction indicated in (b).

[0073] like Figure 2 As shown, because the fibers have no beginning or end in orientation, their direction can be adjusted by rotating the printing platform. Figure 2 (b) After rotating clockwise by an angle P1 in the middle state, it reaches Figure 2 The state in (c) can also be determined by... Figure 2 (b) After rotating counterclockwise by an angle P2 in the middle state, it reaches Figure 2 In state (d), the transfer of fibers arranged along the third direction to the printing platform is completed, and the angle of the printing platform is adjusted.

[0074] The printing platform rotates to Figure 2 (c) state or Figure 2 After the state in (d) is reached, the fiber filaments are transferred to the printing platform. After the fiber filament transfer in this slice layer is completed, the fiber filament transfer in the next slice layer is carried out.

[0075] In the multi-orientation microfiber 3D printing method of the present invention, each slice layer is printed layer by layer to ensure that the fiber filaments in each slice layer have only one orientation. After the fiber filaments of one slice layer are transferred to the printing platform, the fiber filaments of the next slice layer are transferred.

[0076] This invention provides a multi-oriented microfiber 3D printing method, which further includes selective curing. This involves selectively curing the fibers transferred to the printing platform before printing the next slice layer, thus obtaining the target structure to be printed. Selective curing, based on the shape of the target structure and the shapes of each slice layer within it, uses laser light to irradiate the fibers, causing photocrosslinking and shaping the target shape of the slice layer or several consecutive slice layers with identical shapes. Therefore, selective curing can be performed on all fibers in all slice layers or on fibers in several consecutive slice layers with identical shapes.

[0077] To improve the stability of the printed target structure, this printing method prints and cures each slice layer sequentially. Specifically, after the fibers in a slice layer are recovered, selective curing is performed first, and only after the selective curing of this slice layer is complete can the next slice layer be printed. In this way, when the fibers of the subsequent slice layer land on the fibers of the previous slice layer, the fibers adhere to the fibers of the previous slice layer primarily through the adhesiveness and weight of the fibers themselves, ensuring the integrity of the target structure. Figure 2 As shown, after the fiber transfer in a slice layer is completed, the printing platform resets and returns to normal. Figure 2 In state (a), selective curing of the fiber filaments in this layer is performed. After selective curing, the next slice layer is printed. The printing platform is then repositioned to adjust the initial position of the orientation. Figure 2 As shown in (a), ensure adjustment accuracy and reduce adjustment error or equipment error.

[0078] In this invention's method for multi-oriented microfiber 3D printing, selective curing is achieved through photocuring. The photocuring process involves using a 365nm-405nm laser for 5-200 seconds, preferably 10-120 seconds. Under laser irradiation, the fibers undergo a cross-linking reaction, resulting in stable fibers, stable slice layers, and ultimately, a stable target structure. During selective curing, the laser curing range and pattern are controlled based on the shape of the target structure and the shape of the slice layer within it, thereby obtaining the target slice layer.

[0079] This invention provides a multi-directional microfiber 3D printing method, which includes a wetting process. The wetting process involves humidifying the fibers arranged side-by-side along a third direction. The humidification time is 2-10 seconds. The wetting solution typically uses organic solvents such as water, anhydrous ethanol solution, or acetone. This wetting process optimizes the conditions for photocuring crosslinking, thereby improving the reaction efficiency and selective curing quality, preparing the fibers for subsequent photocuring crosslinking. Experiments have shown that the selective curing time for fibers without wetting treatment is over 30 minutes, while the selective curing time for humidified fibers is generally between 10 and 200 seconds, significantly shortening the wetting time and improving printing efficiency. Using anhydrous ethanol solution, water, or acetone to humidify the fibers arranged side-by-side along a third direction provides good humidification, and excess anhydrous ethanol solution is sprinkled between adjacent fibers, preventing excess anhydrous ethanol solution from entering the printing platform.

[0080] In the multi-orientation microfiber 3D printing method of this invention, the process of slicing the target structure along the first direction involves acquiring the target structure data using 3D printing slicing software, inputting the target structure into a host computer, and using the slicing software to acquire the shape of each slice layer and the second direction of the target fibers in each slice layer. In the application of near-field direct writing (NFDW) technology, the 3D printing slicing software is existing software; any existing software system capable of slicing the target structure at the nanoscale can be used. This solution does not involve any modification to the 3D printing slicing software itself.

[0081] In the above scheme, the process of slicing the target structure along the first direction involves using 3D printing slicing software to acquire the target structure data. The host computer inputs the target structure and uses the slicing software to obtain the shape of each slice layer and the second direction of the target fibers in each slice layer. Simultaneously, the host computer also rotates the printing platform by an angle, such as clockwise or counterclockwise. Then, based on the selected rotation direction and the second direction of the target fibers in each slice layer, the printing platform rotation angle is calculated. Here, the printing platform rotation angle is the angle between the orientation of the fibers arranged along the third direction and the second direction. Subsequently, when the printing platform rotates, it rotates according to the rotation angle given by the host computer. After rotation, the orientation of the target fibers on the printing platform is consistent with the orientation of the fibers arranged along the third direction. The fibers arranged along the third direction directly contact the printing platform and are transferred onto the printing platform.

[0082] This invention provides a multi-oriented microfiber 3D printing method, which also includes fiber filament recovery. After selective curing of the last slice layer of the target structure, the fiber structure on the printing platform is immersed in a dissolving solvent. The uncured fiber filaments dissolve in the solvent, obtaining the target structure and a solution containing dissolved fiber filaments. The solution is dried, and the solid containing fiber filaments is separated. Deionized water is typically used as the dissolving solvent. The printed structure on the printing platform is immersed in deionized water. The fiber filaments in the printed structure that have not undergone photocrosslinking and selective curing with the laser dissolve in the deionized water, while the photocrosslinked and selectively cured portions remain undissolved, thus obtaining the target structure. The fiber filaments dissolve in the deionized water to obtain a solution. Finally, the solution is freeze-dried, and the uncrosslinked fibers are collected for future use. This method achieves zero waste discharge and generation, is environmentally friendly and energy-saving, and meets the process requirements of 3D additive printing.

[0083] In this invention's technical solution, a method for multi-oriented microfiber 3D printing, the collected fiber filaments can be prepared using techniques such as electrospinning, melt spinning, or rotational spinning. Generally, the filaments generated by the nozzle in the microfiber generating module are deposited on a receiving module, which consists of two parallel components. The fibers fall onto these two parallel components with their ends overlapping, creating a specific orientation. Then, the rotation angle of the collecting module is controlled to obtain the oriented arrangement of the fibers, i.e., the collected fiber filaments are arranged side-by-side along a third direction.

[0084] In this scheme, electrospinning is the preferred method for preparing fiber filaments.

[0085] In the preparation of fibers by electrospinning, a photocurable material suitable for electrospinning, an electrospinning solvent, a photoinitiator, and a light-blocking agent are mixed to obtain an electrospinning solution. This solution is then placed in a microfiber generation module for spinning. The photocurable material can be any one of methacryloyl gelatin (GEL MA), hyaluronic acid methacrylate (HAMa), or polycaprolactone-ethyl methacrylate copolymer (PCLMA). The electrospinning solvent includes one or more mixtures of hexafluoroisopropanol, acetone, and acetic acid. The photoinitiator is 1-phenyl-2,4,6-trimethylacetophenone (LAP), 2,4,6-tris(trifluoromethyl)phenyl dithiofluorenone (TPO-L), or 2-methyl-4'-(methylmercapto)-2-methyl-1-phenyl-1-propanone (Ifangka 2939). The light-blocking agent is 0.1% curcumin. The selective curing crosslinking light source is a 405nm laser.

[0086] The printed structure on the printing platform is immersed in deionized water. In the printed structure, the parts of the fibers that have not undergone photocrosslinking and selective curing with the laser dissolve in the deionized water, while the parts that have undergone photocrosslinking and selective curing remain undissolved, thus obtaining the target structure. The uncrosslinked fibers, photoinitiator, and opaque agent all dissolve in the deionized water to obtain a solution. Finally, the solution is freeze-dried, and the uncrosslinked fibers, photoinitiator, and opaque agent are collected for future use. This process achieves the discharge and generation of waste materials, is environmentally friendly and energy-saving, and meets the process requirements of 3D additive printing. There is no excess material waste during the printing process.

[0087] This invention provides a multi-oriented microfiber 3D printing method that overcomes the limitations of traditional electrospinning direct spraying technology due to the electrical properties of the fibers. By employing a collection-transfer printing strategy, this invention significantly solves the problems of layer thickness and fiber collection efficiency caused by fiber electrical properties. The concept of this invention allows microfiber printed structures to be printed without thickness limitations, enabling large-scale multi-layer fiber printing, thereby improving 3D printing efficiency and the ability to construct more complex, large-scale structures. Typically, existing technologies can only print structures with a thickness of less than 2 cm, while the target structures printed according to the concept of this invention can generally reach a thickness of over 20 cm.

[0088] This invention provides a multi-oriented microfiber 3D printing method that combines electrospinning and laser curing technologies. This allows for precise control of fiber formation and selective curing at the micrometer to nanometer scale, making it possible to manufacture 3D printed parts with fine structures and high precision. Preferably, electrospinning and laser curing technologies are combined.

[0089] The present invention also provides an application of a multi-orientation microfiber 3D printing method, which is used to print target structures, including but not limited to medical devices, filtration and separation devices, sensing components, and electronic circuit structures.

[0090] To facilitate those skilled in the art to understand the technical concept and solution of the multi-orientation microfiber 3D printing method of the present invention, and to enable those skilled in the art to achieve the purpose of printing target structures after obtaining the technical solution of the multi-orientation microfiber 3D printing method, a printing device suitable for the multi-orientation microfiber 3D printing method is proposed below based on the technical concept of the multi-orientation microfiber 3D printing method of the present invention.

[0091] like Figure 3 As shown, a device suitable for multi-orientation microfiber 3D printing is disclosed.

[0092] See Figure 3 and Figure 4 A multi-orientation microfiber 3D printing device includes a fiber collecting device 3, a fiber orientation and sorting device 4, a printing platform 5, and a platform conveying device 6.

[0093] The fiber orientation and sorting device 4 sorts the fibers collected by the fiber collecting device 3 and obtains oriented fibers. The platform conveying device 6 conveys the printing platform to the position of the fiber orientation and sorting device 4, and the oriented fibers on the fiber orientation and sorting device 4 are transferred to the printing platform.

[0094] The fiber orientation and straightening device 4 straightens the fibers collected by the fiber collecting device 3 and obtains oriented fibers, which are then arranged along a third direction. The oriented fibers arranged along the third direction are transferred to the printing platform 5. During the transfer, the fiber orientation and straightening device 4 controls the fiber orientation, directly transferring the fibers to the printing platform 5 near the fiber orientation and straightening device 4. No electric field needs to be applied to the printing platform. During the transfer of the fibers to the printing platform, the fibers are not subject to electric field forces, enabling the printing of target structures with large thicknesses or heights.

[0095] In the aforementioned multi-orientation microfiber 3D printing equipment, the fiber orientation arranging device 4 arranges the fiber orientation. According to the design concept, this arranging is performed before the fiber is transferred to the printing platform, and then the arranged fiber with a specific or designated orientation is transferred to the printing platform. This differs from existing microfiber 3D printing technologies, where the direction of the fiber landing on the printing platform is controlled by an electric field applied to the platform during the transfer process, or rather, as the fiber is about to land on the platform. The aforementioned multi-orientation microfiber 3D printing equipment first controls the fiber orientation and then transfers the oriented fiber to the printing platform, enabling the printing of target structures with significant thickness or height.

[0096] In the multi-orientation microfiber 3D printing equipment described above, the platform conveying device 6 transports the printing platform to the fiber orientation and sorting device 4, where the oriented fibers are transferred to the printing platform. The platform conveying device 6 ensures that the oriented fibers are laid flat on the printing platform.

[0097] In the multi-orientation microfiber 3D printing equipment of the present invention, see [reference]. Figure 5 The fiber orientation and sorting device 4 includes two fiber conveyor belts 41 arranged opposite to each other, and the two fiber conveyor belts 41 convey fiber synchronously in the same direction.

[0098] The fibers collected by the fiber collecting device 3 enter the fiber orientation and straightening device 4. The two ends of the fibers overlap on two fiber conveyor belts 41 and are conveyed forward with the two conveyor belts 41, resulting in fibers arranged along the conveying direction of the fiber conveyor belts 41. The orientation of the fibers is the direction in which the fibers overlap on the two fiber conveyor belts 41, such as... Figure 5 In the diagram, 10 represents the fiber collected by the fiber collecting device 3, and 20 represents the oriented fiber.

[0099] The printing platform 5 enters the fiber orientation and sorting device 4 from the position below the two fiber conveyor belts 41. The oriented fiber filaments 20 on the fiber orientation and sorting device 4 are transferred to the printing platform by being conveyed by the two fiber conveyor belts 41.

[0100] In the above scheme, the fiber orientation and straightening device 4 employs two oppositely arranged fiber conveyor belts 41, with the two fiber conveyor belts 41 conveying in the same direction and synchronously. This achieves the orientation straightening of the fiber filaments, ensuring that the fiber filaments entering the fiber conveyor belts 41 are arranged along the conveying direction of the fiber conveyor belts 41. The orientation of the fiber filaments arranged along the conveying direction of the fiber conveyor belts 41 is the overlapping direction of the fiber filaments on the two fiber conveyor belts 41. That is, in the above scheme, the fiber orientation and straightening device 4 uses two oppositely arranged fiber conveyor belts 41 to transfer the fiber filaments collected by the fiber collecting device 3 to the two fiber conveyor belts 41, with both ends overlapping on the fiber conveyor belts 41. The fiber filaments are conveyed with the fiber conveyor belts 41, i.e., arranged along the conveying direction of the fiber conveyor belts 41. The conveying direction of the fiber conveyor belts 41 is the third direction.

[0101] In the above scheme, the fiber orientation and sorting device 4 uses two fiber conveyor belts 41 arranged opposite to each other. The fiber conveyor belts 41 not only sort the fiber orientation but also transport the fiber, allowing the fiber on the fiber conveyor belts 41 to smoothly enter the printing platform. The printing platform 5 enters the fiber orientation and sorting device 4 from below the two fiber conveyor belts 41. The fiber conveyor belts 41 and the printing platform 5 have a relative movement, allowing the fiber on the fiber conveyor belts 41 to be laid flat on the printing platform 5.

[0102] In the multi-orientation microfiber 3D printing equipment of the present invention, the outer diameter of the printing platform is not greater than the distance between the two fiber conveyor belts 41, which facilitates the smooth entry of the printing platform 5 between the two fiber conveyor belts 41 and the transfer of the oriented fibers on the fiber conveyor belts 41 to the printing platform, avoiding interference between the printing platform and the fiber conveyor belts 41, and ensuring that the printing platform smoothly receives the oriented fibers on the fiber conveyor belts 41.

[0103] See Figure 5 The fiber conveyor belt 41 is inclined, and the fiber filaments are conveyed from the high end to the low end of the fiber conveyor belt 41. The printing platform 5 enters between the two fiber conveyor belts from the low end of the fiber conveyor belt 41. The oriented fiber filaments 20 on the fiber conveyor belts are conveyed with the two fiber conveyor belts 41 and transferred to the printing platform near the low end of the fiber conveyor belt 41.

[0104] Due to the weight of the fibers themselves, the fibers are conveyed along the downward-sloping fiber conveyor belt 41, sliding a certain distance along it. This further facilitates the orientation of the fibers entering the conveyor belt. In other words, the fiber conveyor belt is set to a downward-sloping position, ensuring the conveying of the limiting fibers while simultaneously achieving fiber orientation. During printing, the printing platform 5 enters the space between the two fiber conveyor belts 41 from the lower end. The printing platform 5 intersects with the conveying surface formed by the upward-sloping fiber conveyor belts, transferring the oriented fibers from the conveyor belts to the printing platform.

[0105] See Figure 5 and Figure 6 The platform conveying device 6 includes a platform conveyor belt 60. One end of the platform conveyor belt 60 is located directly below the conveying surface of the fiber conveyor belt 41, and the other end is located outside the conveying surface of the fiber conveyor belt 41. This ensures that the printing platform conveyed by the platform conveyor belt intersects with the conveying surface of the fiber conveyor belt, allowing the oriented fibers on the fiber conveyor belt to be transferred to the printing surface of the printing platform. The printing platform is mounted on the conveying surface of the platform conveyor belt 60 and is conveyed forward with the platform conveyor belt 60. The printing surface 50 of the printing platform 5, conveyed by the platform conveyor belt 60, intersects with the conveying surface of the fiber conveyor belt 41. The oriented fibers on the fiber conveyor belt 41 are transferred to the printing platform at the intersection of the printing surface 50 of the printing platform 5 and the conveying surface of the fiber conveyor belt 41.

[0106] During printing, the fiber conveyor belt 41 and the platform conveyor belt 60 transport fibers at a uniform speed. The fiber conveyor belt 41 transports the oriented fibers downwards and intersects with the printing surface of the forward-moving printing platform, transferring the oriented fibers onto the printing platform. During the fiber transfer process on the current printing surface, the conveyor platform and the fiber conveyor belt always maintain a forward-moving state, ensuring that the oriented fibers are laid flat on the printing surface of the printing platform, so that the entire printing surface is covered with fibers.

[0107] Oriented filaments on the filament conveyor belt are transferred to the printing platform near the lower end of the filament conveyor belt 41, so that the filaments are transported through almost the entire filament conveyor belt, adjusting their orientation to ensure that oriented filaments are obtained.

[0108] See Figure 8 , Figure 9 and Figure 10 As shown, the printing surface 50 of the printing platform 5 can be tilted upwards (e.g., Figure 8 (a) in the middle, sloping upwards (e.g.) Figure 9 (a) or horizontal (e.g.) Figure 10(a) The fiber filaments 20 with orientation on the fiber filament conveyor belt 41 enter between the two fiber filament conveyor belts from the lower end and intersect with the conveying surface of the fiber filament conveyor belt, so that the fiber filaments 20 with orientation on the fiber filament conveyor belt are transferred to the printing surface of the printing platform 5.

[0109] The printing surface 50 of the printing platform 5 intersects with the conveying surface of the fiber conveyor belt, transferring the oriented fiber filaments 20 arranged on the fiber conveyor belt to the printing surface of the printing platform. As the printing height increases, the intersection position of the printing surface 50 of the printing platform 5 and the conveying surface of the fiber conveyor belt moves along the upwardly inclined conveying surface of the fiber conveyor belt, such as... Figure 8 (b) Figure 9 (b) and Figure 10 As shown in (b), as the fiber filaments accumulate on the printing surface, the printing height increases, the printing surface moves upward, and the position where the printing surface 50 of the printing platform 5 intersects with the conveying surface of the fiber filament conveyor belt moves along the upwardly inclined conveying surface of the fiber filament conveyor belt.

[0110] See Figure 8 , Figure 9 and Figure 10 As shown, the printing surface 50 of the printing platform 5 can be tilted upwards (e.g., Figure 8 (a) in the middle, sloping upwards (e.g.) Figure 9 (a) or horizontal (e.g.) Figure 10 (a) The fiber conveyor belt enters the space between the two fiber conveyor belts from the lower end of the fiber conveyor belt 41 and intersects with the conveying surface of the fiber conveyor belt. That is, the printing platform can be conveyed in an inclined upward, inclined downward, or horizontal state. To simplify the printing platform structure, the printing platform is generally set as a column, that is, the upper surface and the bottom surface of the printing platform are parallel. When the printing platform is installed on the platform conveyor belt 60, the bottom surface of the printing platform is generally installed with the platform conveyor belt 60, that is, the platform conveyor belt 60 can be conveyed in an inclined upward, inclined downward, or horizontal state, such as... Figure 8 , Figure 9 and Figure 10 As shown.

[0111] In one embodiment, such as Figure 5 and Figure 6 As shown, the platform conveyor belt 60 includes an inclined section 61, which intersects spatially with the fiber conveyor belt 41. When the printing platform 5, mounted on the platform conveyor belt 60, is conveyed to the inclined section 61, the printing surface of the printing platform 5 becomes inclined, intersecting with the inclined fiber conveyor surface, transferring the fibers from the fiber conveyor belt to the printing surface of the printing platform, such as... Figure 8 and Figure 9 .

[0112] like Figure 8As shown, the inclined section 61 of the platform conveyor belt 60 conveys upwards at an angle, intersecting with the conveying surface of the fiber conveyor belt, and the oriented fiber filaments are laid flat on the printing surface of the upwardly conveying printing platform. Figure 9 As shown, the inclined section 61 of the platform conveyor belt 60 is inclined downward and intersects with the conveying surface of the fiber conveyor belt, and the oriented fiber filaments are laid flat on the printing surface of the inclined downward conveying printing platform.

[0113] like Figure 8 and Figure 9 As shown, when the printing surface of the printing platform intersects with the conveying surface of the fiber conveyor belt, the oriented fibers are transferred to the printing surface. The ends of the fibers laid flat on the printing surface continue to be conveyed forward until they reach below the conveying surface. At this point, to avoid interference between the fibers laid flat on the printing platform and the fibers on the conveying surface, the distance between the printing surface and the conveying surface should be higher than the outer diameter of the fibers. That is, in the design of the inclination angle of the inclined section 61 of the platform conveyor belt 60, it is necessary to ensure that after the printing surface intersects with the conveying surface, the distance between the printing surface and the conveying surface should be higher than the outer diameter of the fibers.

[0114] Generally, the fibers conveyed along the fiber conveyor belt are not all seamlessly attached. There is usually a certain distance between two adjacent oriented fibers, and the outer diameter of the fiber is generally at the nanometer level. Therefore, when the printing surface and the conveyor surface intersect, the distance between the printing surface and the conveyor surface will be higher than the outer diameter of the fiber, so there will be no interference problem.

[0115] In the above embodiments, the platform conveyor belt is equipped with an inclined section to achieve inclined conveying of the printing platform. That is, the printing surface of the printing platform receives oriented fibers at an inclined state, which facilitates the adhesion and bonding of the fibers transferred to the printing platform. Especially between adjacent fibers in the same horizontal layer, due to the inclined setting of the printing platform, the gravity of the fibers transferred to the printing platform has a decomposition force perpendicular to the printing surface and a decomposition force parallel to the printing surface. The decomposition force perpendicular to the printing surface compresses the fibers of the previous layer, facilitating the bonding of this fiber with the fibers of the previous layer, while the decomposition force parallel to the printing surface exerts a compressive force on adjacent fibers, facilitating the bonding of this fiber with adjacent fibers. Therefore, the inclined setting of the printing platform facilitates tight bonding between fibers in each layer and between adjacent fibers in the same layer, improving the structural stability of the printed target structure.

[0116] Because the outer diameter of the fiber filaments is nanometer-scale, which is extremely small, in order to improve printing efficiency and ensure precise bonding between adjacent filaments, the printing platform can reciprocate multiple times during the process of receiving the fiber filaments at the intersection of the printing surface and the conveyor surface of the fiber filament conveyor belt. This allows the fiber filaments to be laid out in multiple layers on the printing platform. In one conveying cycle of the printing platform, the fiber filaments should be laid out evenly across the entire printing surface before the reciprocating motion is repeated. Each time the fiber filaments are laid out, the entire printing surface is ensured to be covered evenly.

[0117] To facilitate the control and fixation of the intersection position between the printing surface of the printing platform and the conveying surface of the fiber conveyor belt, in one embodiment, the conveying angle of the fiber conveyor belt is controlled to ensure that, for example... Figure 8 (c) Figure 9 (c) and Figure 10 As shown in (c).

[0118] An angle adjustment device 43 for adjusting the tilt angle of the fiber conveyor belt 41 is connected to the fiber conveyor belt 41. The angle adjustment device 43 includes a fixed base 431 and an adjustment base 432 hinged to the fixed base 431. Two mounting brackets 42 are fixedly connected to the adjustment base 432, and the two fiber conveyor belts 41 are respectively mounted on the two mounting brackets 42.

[0119] An adjustment component 434 is connected between the adjustment base 432 and the fixed base 431. The adjustment component 434 drives the adjustment base 432 to rotate around the hinge position 433 with the fixed base 431.

[0120] During printing, the drive assembly drives the adjustment base 432 to rotate upward, raising the intersection position of the conveying surface of the fiber conveyor belt 41 and the printing surface of the printing platform.

[0121] like Figure 8 (c) Figure 9 (c) and Figure 10 As shown in (c), as the fibers accumulate on the printing platform, the printed portion 30 of the target structure is obtained on the printing platform. The position of the printed surface on the printing platform rises accordingly. At this time, the tilt angle of the fiber conveyor belt 41 is controlled by the angle adjustment device 43. Specifically, the tilt angle of the fiber conveyor belt 41 is increased to raise the conveying surface of the fiber conveyor belt 41, ensuring that the intersection position between the conveying surface of the fiber conveyor belt 41 and the printed surface on the printing platform remains unchanged. This ensures that the fibers conveyed along the fiber conveyor belt 41 are always delivered to a fixed position on the fiber conveyor belt. Because the target structure is formed by layering fibers during printing, controlling the tilt angle of the fiber conveyor belt through the angle adjustment device 43 is more precise than controlling the fiber conveying position on the fiber conveyor belt, thus improving the accuracy of microfiber printing.

[0122] In one embodiment, the adjusting component 434 includes, but is not limited to, a cylinder, a linear motor, a motor cam mechanism, and a motor linkage mechanism. For example... Figure 5 As shown, the adjusting component 434 is driven by a cylinder. The two ends of the cylinder are hinged to the fixed base and the adjusting base, respectively. The extension and retraction of the cylinder controls the tilt angle of the adjusting base, and thus the tilt angle of the fiber conveyor belt. Similarly, when a linear motor is used, the motor body and the front end of the motor shaft are hinged to the fixed base and the adjusting base, respectively. The extension and retraction of the motor shaft controls the tilt angle of the adjusting base. The motor cam mechanism typically uses a motor to drive a cam to rotate. The cam surface contacts the bottom surface of the adjusting base, and the position of the adjusting base is controlled by the convex surface of the cam, thus controlling the rotation of the adjusting base and achieving the installation of the adjusting base's tilt angle.

[0123] In this solution, the multi-orientation microfiber 3D printing equipment also includes a host computer 2 and a platform orientation adjustment device 51. The host computer 2 acquires the sliced ​​layers of the target structure along a first direction, and simultaneously acquires the orientation of the target fibers in each sliced ​​layer. The first direction is the stacking direction of the target fiber layers of the target structure, and the orientation of the target fibers in the sliced ​​layers is the second direction.

[0124] The printing platform is mounted on the platform orientation adjustment device 51, which in turn is mounted on the platform conveying device 6. During printing, before the fibers are transferred from the fiber orientation and sorting device 4 to the printing platform, the platform orientation adjustment device 51 adjusts the orientation of the printing platform based on the target fiber orientation in the slice layer being printed, obtained from the host computer 2. After the printing platform is adjusted, the target fiber orientation on the printing platform is consistent with the orientation of the oriented fibers on the fiber orientation and sorting device 4.

[0125] A 3D printing slicing software is installed on the host computer. The host computer 2 acquires the sliced ​​layers of the target structure along the first direction, and simultaneously acquires the orientation of the target fibers in each sliced ​​layer, all accomplished by the 3D printing slicing software. The process of slicing the target structure along the first direction involves acquiring the target structure data using the 3D printing slicing software, inputting the target structure into the host computer, and using the slicing software to acquire the shape of each sliced ​​layer and the second orientation of the target fibers in each sliced ​​layer. In the application of near-field direct writing (NFDW) technology, the 3D printing slicing software is existing software; any existing software system capable of slicing the target structure at the nanometer level will suffice. This solution will not make any improvements to the 3D printing slicing software itself.

[0126] While the host computer 2 obtains the sliced ​​layers of the target structure along the first direction through the 3D printing slicing software, and obtains the orientation of the target fiber filaments in each sliced ​​layer, it also obtains the printing platform adjustment angle based on the orientation of the target fiber filaments in each sliced ​​layer, and uses this angle as the basis and parameter for the platform orientation adjustment device 51 to adjust the printing platform angle.

[0127] The platform orientation adjustment device 51 selects the rotation direction of the printing platform, such as clockwise or counterclockwise, based on the acquired printing platform adjustment angle, and then controls the printing platform to rotate. Here, the printing platform rotation angle is the angle between the orientation of the oriented fibers (the orientation of fibers arranged along a third direction) on the fiber conveyor belt and the second direction. Generally, the printing platform angle is adjusted before conveying. For target structures where all target fibers have a single orientation, printing platform angle adjustment is not required; direct printing platform conveying is sufficient.

[0128] In one embodiment, such as Figure 6 As shown, the platform orientation adjustment device 51 includes a mounting base 511 fixedly installed on the platform conveying device 6 and a motor 512 installed on the mounting base 511. The output shaft of the motor 512 is fixedly connected to the printing platform 5, driving the printing platform 5 to rotate. The rotation angle output by the motor 512 is controlled by the host computer. Using a motor to control the rotation of the printing platform is simple in structure and convenient and precise in control.

[0129] The multi-orientation microfiber 3D printing equipment of the present invention further includes a wetting device 7, which is disposed above the fiber orientation and sorting device 4. The wetting device 7 wets the fibers on the fiber orientation and sorting device 4 that are to be transferred to the printing platform. The wetting device 7 includes a liquid reservoir 71 and an automatic nozzle 72 connected to the liquid reservoir 71, the automatic nozzle 72 being directed towards the fibers conveyed on the fiber orientation and sorting device 4. The wetting device wets the fibers on the fiber orientation and sorting device 4. The installation position of the wetting device 7 should ensure that it is installed before the fibers are transferred to the printing platform, and should be as close as possible to the upper end of the fiber conveyor belt. It is necessary to ensure that the wetting device does not wet the fibers already transferred to the printing platform to avoid over-wetting.

[0130] In this invention, the multi-orientation microfiber 3D printing equipment further includes a selective curing device, which is positioned above the end of the platform conveyor belt located on the outer side of the fiber conveyor belt. The selective curing device cures the fiber filaments transferred to the printing platform. A lifting device 81 is connected to the selective curing device 8. The lifting device 81 drives the selective curing device 8 to move up and down, adjusting the distance between the selective curing device 8 and the fiber filament layer to be cured on the printing platform located at the horizontal segment 62.

[0131] The selective curing device 8 uses laser curing. During curing, a target pattern is formed on the fiber filament layer to be cured. The distance between the selective curing device 8 and the fiber filament to be cured is adjusted by the lifting device 81 to ensure that the laser is focused on the fiber filament layer to be cured and to ensure that the curing proceeds normally.

[0132] To simplify the installation of the selective curing device 8 and the distance adjustment between the selective curing device 8 and the fiber to be cured, the curing laser is focused on the fiber layer to be cured. At the curing position, the fiber layer to be cured is in a horizontal state, that is, the printing platform is in a horizontal state. That is, the platform conveyor belt 60 includes a horizontal section 62, which is connected to one end of the inclined section 61 and is located outside the conveying surface of the fiber conveyor belt.

[0133] In one embodiment, the lifting device 81 includes a drive motor 84 and a vertical lead screw 83 fixedly connected to the drive motor 84. The selective curing device 8 is threadedly connected to the vertical lead screw 83. The drive motor drives the vertical lead screw to rotate, and the selective curing device 8, threadedly connected to the vertical lead screw, moves up and down along the vertical lead screw. To further ensure the installation stability of the selective curing device 8 and the stability of the lifting process, the lifting device also includes a guide post 82 parallel to the vertical lead screw. The selective curing device 8 is mounted on the guide post and moves up and down along the guide post.

[0134] In the technical solution of the present invention, a microfiber generating device is provided at the front of the fiber collecting device 3, and the fiber generated by the microfiber generating device is collected by the fiber collecting device 3.

[0135] The fiber collecting device 3 includes two rotating disks 31 arranged opposite each other. The two rotating disks 31 are coaxial and rotate synchronously in the same direction. The fiber filaments generated by the microfiber generating device overlap between the two rotating disks 31. Both rotating disks 31 are located at the high end of the fiber filament conveyor belt 41 and are respectively arranged on the outside of the two fiber filament conveyor belts 41. When the rotating disks 31 rotate, the fiber filaments collected between the two rotating disks 31 are transferred from the high end of the two fiber filament conveyor belts 41 to the fiber filament conveyor belt 41.

[0136] The microfiber generator produces fibers. These fibers gain inertia the instant they are ejected from the generator. Under this inertia, the fibers move between two rotating disks 31. Simultaneously, under the influence of the internal electric field of the microfiber generator, their ends contact the two opposing and synchronously rotating disks 31, thus collecting the fibers. After being collected between the two rotating disks 31 of the fiber collecting device 3, the fibers only gain one degree of freedom; they have no fixed orientation, and adjacent fibers are not parallel, or even maintain a state of near-parallelism. Figure 5As shown, the fibers between the two turntables are initially random. The rotation of the turntables then transfers the fibers to the two fiber conveyor belts of the fiber orientation and straightening device. The fibers are collected and conveyed forward by the conveyor belts. The inclined conveyor belts adjust the orientation of the fibers overlapping at both ends, thus oriented the fibers. Therefore, in this solution, by setting up the fiber orientation and straightening device after the initial fiber collection, a secondary collection of fibers is achieved, and the fiber orientation is adjusted to obtain oriented fibers, providing a foundation for subsequent transfer of the fibers to the printing flat belt.

[0137] The multi-orientation microfiber 3D printing equipment of the present invention also includes a chassis 1, a host computer, a microfiber generating device, a fiber collecting device, a fiber orientation and sorting device, a printing platform, a platform conveying device, a humidifying device, and a selective curing device, all of which are placed inside the chassis 1. During printing, the door of the chassis 1 is closed, and the internal printing process can be observed only from the outside of the transparent door. Of course, the printing process and printing status will also be displayed synchronously on the host computer.

[0138] The multi-directional microfiber 3D printing equipment of the present invention also includes a fiber filament recycling device. The fiber filament recycling device has an immersion tank filled with a dissolving solvent. The printed and cured structure is placed in the immersion tank, and the uncured fiber filaments are dissolved in the dissolving solvent to obtain the target structure. At the same time, a solution containing dissolved fiber filaments is obtained. The solution is dried and separated to obtain a solid containing fiber filaments.

[0139] To facilitate understanding of the printing equipment of this solution by those skilled in the art, an embodiment of the printing process of this multi-orientation microfiber 3D printing equipment is given below.

[0140] First, start the equipment. The host computer then begins operation, inputting the target structure to be printed. The 3D printing slicing software processes the target structure, including slicing the target structure; obtaining slice layers; obtaining the target fiber orientation within each slice layer; obtaining the slice layer thickness; obtaining the angle the printing platform needs to adjust during printing each slice layer; and obtaining the number of reciprocating strokes the printing platform needs to receive the fiber filaments during printing each slice layer, i.e., obtaining the number of fiber filament layers that need to be laid flat on the printing surface when printing each slice layer.

[0141] Then, the microfiber generating device, the fiber collecting device, and the fiber orientation and finishing device are activated. The microfiber generating device generates fibers, which are then collected by the fiber collecting device. The collected fibers enter the fiber orientation and finishing device to obtain oriented fibers.

[0142] Simultaneously, the platform orientation adjustment device, platform conveying device, and humidification device are activated. First, the printing platform angle is adjusted as needed. Then, the platform conveying device transports the printing platform to the intersection position of the fiber conveyor belt's conveyor surfaces. Generally, to improve printing efficiency and avoid fiber accumulation on the fiber conveyor belt, the printing platform arrives at the intersection position before the first fiber.

[0143] After the first fiber filament on the fiber conveyor belt reaches the intersection point, the platform conveyor restarts, and the printing platform moves forward. Simultaneously, the fiber conveyor belt continues to transport the fiber filaments, which are then laid flat on the conveyor surface of the printing platform. At this point, after the printing platform has traveled a distance equal to its outer diameter in this direction, it reverses direction, and the fiber filaments on the fiber conveyor belt are transferred again and laid flat on the printing surface of the printing platform. This time, the laying direction of the fiber filaments on the large printing surface is opposite to the previous laying direction. This process is repeated multiple times, achieving the laying of multiple layers of fiber filaments on the printing surface, until all the fiber filaments in the current slice layer have been transferred. Then, the fiber conveyor belt stops transporting, and the printing platform, under the action of the platform conveyor device, moves to the selective curing device for selective curing of the fiber filaments.

[0144] By adjusting the height of the selective curing device, the curing laser is focused on the fiber layer to be cured, thus obtaining the desired cured pattern.

[0145] After the fibers of this slice layer have cured, repeat the previous printing process to print the next slice layer.

[0146] After the printing and curing operations are completed, the printed structure is immersed in a fiber recycling device to obtain the target structure, and the fibers that have not undergone photocrosslinking are collected and can be reused.

[0147] Import the STL file into the host computer software for slicing, and input the target fiber angle for each slice layer and the angle that the printing platform needs to be adjusted.

[0148] 1. Start the microfiber generator. The microfiber generator is equipped with an injection pump that outputs fiber filaments at a rate of 1 ml / h. The high voltage in the microfiber generator is set to 15 kV.

[0149] 2. Activate the fiber collecting device, fiber orientation and straightening device, printing platform, platform conveying device, wetting device, and selective curing device. The microfiber generating device then begins to produce microfibers that are deposited onto the rollers formed by the two opposing rotating discs of the fiber collecting device. The fibers on the rotating discs are further deposited onto the fiber conveyor belt of the fiber orientation and straightening device. The rotating discs rotate at 100 rpm, and the fiber conveyor belt travels at 10 rpm.

[0150] 3. Place anhydrous ethanol solution into the humidification device, start the humidification device, and continuously humidify the fibers on the fiber conveyor belt.

[0151] 4. The printing platform rotates at a preset angle and conveys the fibers to the fiber conveyor belt. The printing platform can be of any shape, and its size can be selected as needed. The size is 10×10cm². When receiving fibers, the printing platform moves back and forth at a constant speed of 10cm / min, with one collection cycle taking 10 minutes. If a circular printing platform with a diameter of 10cm is used, it can reciprocate 5 times in 10 minutes, collecting 10 layers of thick fibers. Of course, the printing platform can also be other sizes, and other printing durations can be selected as needed.

[0152] After the 5.10-minute fiber collection process of the printing platform is completed, the printing platform returns to its initial position and then moves to the position of the selective curing device.

[0153] 6. DLP projects the corresponding pattern using slicing software, and selects a 405nm light source for photocuring.

[0154] 7. After one exposure and curing cycle, repeat the previous step until printing is complete.

[0155] 8. Immerse the obtained print in deionized water. The uncrosslinked microfibers will dissolve in the water, while the target structure will be reflected in the water.

[0156] 9. Collect the dissolved deionized water, freeze-dry the uncrosslinked fibers, photoinitiator, and opaque agent, and wait for the next use.

[0157] This invention provides a multi-orientation microfiber 3D printing device. A fiber orientation straightening device aligns the fiber filaments to obtain oriented fibers. Then, based on the orientation of the target fiber filaments in the target structure, a platform orientation adjustment device adjusts the orientation of the printing platform. This ensures that the entire process of transferring the fiber filaments to the printing platform is controlled by mechanical action to obtain the target fiber filaments, eliminating the reliance on electric field force to control the orientation of the fiber filaments as they land on the printing platform. This overcomes the limitations of the target structure's printing height, theoretically making the printed target structure unlimited.

[0158] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A method for multi-orientation microfiber 3D printing, characterized in that, The target structure is sliced ​​along the first direction to obtain sliced ​​layers; the orientation of the target fiber filaments in each sliced ​​layer is obtained. The first direction is the stacking direction of the target fiber filament layers of the target structure, and the orientation of the target fiber filaments in the slice layer is the second direction; Collect the fibers and arrange them side by side along a third direction; The fiber filaments arranged along the third direction are used to print each slice layer in the target structure onto the printing platform one by one; Based on the orientation of the target fiber filament in the slice layer being printed, the orientation of the printing platform is adjusted so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filament in the slice layer being printed on the printing platform, and the fiber filament is transferred to the printing platform. After the fiber transfer of each slice is completed, the fiber transfer of the next slice is carried out.

2. The multi-orientation microfiber 3D printing method according to claim 1, characterized in that, The first direction is perpendicular to the slice layer, and the first direction is perpendicular to the second direction; the third direction includes the second direction.

3. The multi-orientation microfiber 3D printing method according to claim 1 or 2, characterized in that, In the third direction, adjacent fibers are parallel or nearly parallel.

4. The multi-orientation microfiber 3D printing method according to claim 1 or 2, characterized in that, Within the sliced ​​layer, the target fiber filament is unidirectional.

5. The multi-orientation microfiber 3D printing method according to claim 1 or 2, characterized in that, Before the fiber filaments are transferred to the printing platform, the orientation of the fiber filaments arranged along the third direction is maintained according to the orientation of the target fiber filaments in the slice layer being printed. The printing platform is rotated so that the orientation of the fiber filaments arranged along the third direction is consistent with the orientation of the target fiber filaments in the slice layer being printed on the printing platform. The rotation angle of the printing platform is the angle between the orientation of the fibers arranged along the third direction and the second direction, and the rotation direction of the rotating platform is either clockwise or counterclockwise. The fibers arranged along the third direction come into direct contact with the printing platform and are transferred onto the printing platform.

6. The multi-orientation microfiber 3D printing method according to claim 1, characterized in that, It also includes selective curing, which selectively cures the fibers transferred to the printing platform, and then prints the next slice layer after selective curing is completed. The selective curing is photocuring, and the photocuring process involves using a 365nm-405nm laser to cure for 5s-200s.

7. The multi-orientation microfiber 3D printing method according to claim 1 or 6, characterized in that, It also includes a humidification process, which involves humidifying the fibers arranged side by side along the third direction for a time of 2-10 seconds.

8. The multi-orientation microfiber 3D printing method according to claim 1, characterized in that, The process of slicing the target structure along the first direction involves using 3D printing slicing software to obtain the data of the target structure, inputting the target structure into the host computer, and using the slicing software to obtain the shape of each slice layer and the second direction of the target fibers in each slice layer.

9. The multi-orientation microfiber 3D printing method according to claim 1, characterized in that, It also includes fiber filament recovery. After the last slice layer of the target structure is selectively cured, the fiber structure on the printing platform is immersed in a dissolving solvent. The uncured fiber filaments are dissolved in the dissolving solvent to obtain the target structure. At the same time, a solution containing dissolved fiber filaments is obtained. The solution is dried and separated to obtain a solid containing fiber filaments.

10. An application of a multi-orientation microfiber 3D printing method, characterized in that, The target structure is obtained by printing using any one of the multi-orientation microfiber 3D printing methods of claims 1 to 9. The target structure includes, but is not limited to, medical devices, filtration and separation devices, sensing components, and electronic circuit structures.

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