Variable-precision volume biological 3D printing system and printing method thereof

Abstract

The invention relates to the technical field of biological volume printing, and discloses a variable-precision volume biological 3D printing system which comprises a controller, a printer shell, a projection module, a printing module and an ink supply mechanism, and the projection module, the printing module and the ink supply mechanism are arranged in the printer shell. The printing module comprises a light-transmitting cylindrical printing container and a printing rotating mechanism for driving the printing container to rotate around the axis; the projection module is installed through a first sliding mechanism and controlled by the controller so as to move in the direction parallel to the axis of the printing container. And the controller is configured to cooperatively control the first sliding mechanism and the projection module, so that when the projection module moves to different height positions, two-dimensional image sequences which correspond to the positions and have different resolutions or different image contents are switched to be projected to the rotating printing container, and the printing container rotates. Therefore, the variable-precision printing of the three-dimensional biological structure is realized.

Description

Technical Field

[0001] This invention relates to the field of bio-volume printing technology, and more specifically to a variable precision volumetric bio-3D printing system and its printing method. Background Technology

[0002] Volumetric bio-3D printing, as an emerging biomanufacturing technology, achieves three-dimensional solidification of photosensitive bio-inks through holographic reconstruction and multi-angle projection, possessing the potential for rapid prototyping of complex biological structures. However, this technology still faces several key bottlenecks in practical applications, limiting its precision control, printing efficiency, and multi-material integration capabilities, specifically as follows: First, existing volumetric bio-3D printing systems lack an effective real-time control mechanism for forming accuracy. Because the entire printing process relies on a preset light field distribution for one-time curing, it is impossible to dynamically adjust the curing accuracy according to local structural features or process requirements. This leads to problems of insufficient or over-curing when printing microstructures, affecting the morphological fidelity and functional realization of the formed structure.

[0003] Secondly, current technology faces a trade-off between curing efficiency and molding quality when printing large-scale structures. As the printed volume increases, the number of projected images and the rotation angle increase accordingly, which not only significantly prolongs the printing time but also causes edge blurring and dimensional distortion due to the intensified scattering of the light field in the deeper ink layers, thus limiting the application of this technology in large-scale biomanufacturing.

[0004] Furthermore, volumetric bio-3D printing currently struggles to achieve integrated molding of multiple materials. Due to the varying photosensitivity and curing thresholds of different bio-inks, integrating multiple materials in the same printing process requires complex light field modulation systems and material switching mechanisms. Existing equipment generally lacks the corresponding material synergistic control capabilities, making the construction of heterogeneous tissue interfaces and functionally graded structures challenging.

[0005] Finally, despite the high cost of bio-inks, current processes typically discard the residual ink containing semi-cured particles after printing, further increasing usage costs. It should be noted that, in addition to material waste, uncontrollable precision, low efficiency in large-size printing, and insufficient multi-material printing capabilities are the core problems that current volumetric bio-3D printing technology urgently needs to solve to achieve practical application. Summary of the Invention

[0006] The purpose of this invention is to provide a variable precision volumetric bio-3D printing system and printing method thereof to solve at least one technical problem described in the background art.

[0007] To achieve the above objectives, the present invention provides a variable precision volumetric bio-3D printing system, including a controller, a printer housing, and a projection module, a printing module, and an ink supply mechanism disposed in the printer housing; The printing module includes a light-transmitting cylindrical printing container and a printing rotation mechanism that drives it to rotate around an axis. The projection module is mounted via a first sliding mechanism and controlled by the controller to move in a direction parallel to the axis of the printing container. The controller is configured to coordinate the control of the first sliding mechanism and the projection module, so that when the projection module moves to different height positions, it switches the projection of a sequence of two-dimensional images with different resolutions or different image contents corresponding to each position onto the rotating printing container, thereby realizing variable precision printing of three-dimensional biological structures.

[0008] When using this variable-precision volumetric bio-3D printing system, the ink supply mechanism adds bio-ink to the printing container from directly above it. The controller controls the printing container to rotate at a constant speed. As the printing container rotates, the projection module switches its projected two-dimensional image according to the phase change of the printing container's rotation, thus solidifying the bio-ink and forming the desired biological structure. This invention overcomes the limitations of fixed precision in existing technologies. It allows for high-resolution solidification of complex and intricate areas of the three-dimensional biological structure in a single print, while macroscopic support areas are rapidly formed using lower resolution, balancing printing precision and efficiency. It avoids the inefficient practice of using the highest resolution throughout to accommodate local fine features, significantly shortening the overall printing time for large-scale complex structures and saving computational resources.

[0009] In some embodiments, a high-resolution lens assembly is provided in the projection optical path of the projection module. The high-resolution lens assembly is detachably connected to the projection module, and the light source emitted from the projection lens can illuminate the printing container after passing through the high-resolution lens assembly, thereby improving the resolution of the projected image.

[0010] In some embodiments, the printing rotation mechanism is mounted inside the printer housing via a second sliding mechanism; the controller is configured to control the second sliding mechanism to drive the printing container to reciprocate along a direction parallel to the projection optical axis of the projection module when the high-resolution lens assembly is installed, so as to adapt to the focal length change of the two-dimensional image modulated by the high-resolution lens assembly and ensure projection clarity.

[0011] In some embodiments, the ink supply mechanism includes multiple independent ink supply units, each including an ink supply pump, an ink reservoir, an ink conduit, and an ink nozzle; the ink supply pump is capable of transmitting bio-ink stored in the ink reservoir to the ink nozzle through the ink conduit, the ink nozzle being located above the top opening of the printing container to add bio-ink to the printing container; In some embodiments, the ink supply mechanism further includes a third sliding mechanism through which all the ink nozzles can move vertically to approach or move away from the top opening of the printing container.

[0012] In some embodiments, a filtering module is also included, the filtering module comprising a screen and a recycling box, the recycling box having a recycling opening at the top, the screen being detachably connected to the top of the recycling box via a first mounting structure and capable of covering the recycling opening.

[0013] In some embodiments, the first mounting structure includes a first mounting portion extending vertically around the inner wall of the recycling box and a second mounting portion extending horizontally outward from the top of the first mounting portion. The first mounting portion is capable of fitting against the inner wall of the top of the recycling box, and the bottom of the second mounting portion is capable of pressing against the top surface of the recycling box.

[0014] In some embodiments, the bottom of the printing container is provided with a movable cover, which can open or close the bottom opening of the printing container. The movable cover is equipped with a rotating rod, and the movable cover is rotatably connected to the bottom of the printing container via the rotating rod. The bottom of the printing container is also equipped with a servo motor, and the output shaft of the servo motor is coaxially connected to the rotating rod so as to drive the movable cover to rotate. When the movable cover is opened, the solidified biological structure and the unsolidified remaining biological ink can flow out together to the filter module, which separates the biological structure from the remaining biological ink to achieve ink recycling.

[0015] In some embodiments, the printing rotation mechanism includes a connecting frame and fixed bearings and a hollow turntable respectively disposed at the top and bottom ends of the connecting frame. The bottom end of the printing container passes through a hole in the hollow turntable and can be fixedly connected to the hollow turntable by a set screw. The top end of the printing container is rotatably connected to the fixed bearing.

[0016] Another aspect of the present invention provides a variable precision volumetric bio-3D printing method, which includes the following steps: S1, establishing a projection model, performing tomographic scanning on the target printed object to obtain a two-dimensional image sequence, and converting the two-dimensional image sequence into a three-dimensional digital projection model through holographic reconstruction technology; S2, ink injection, injecting bio-ink into the printing container through an ink supply mechanism; S3, projection curing, the projection module projects curing light onto the rotating printing container according to the three-dimensional digital projection model; S4, removal and cleaning, after the bio-structure has been cured, the printing rotation mechanism is closed and the bottom opening of the printing container is opened, allowing the bio-structure and remaining bio-ink to flow out to the filtration module, the remaining bio-ink flows through the screen into the recycling box for recycling and reuse, the bio-structure remains on the screen, and the bio-structure is cleaned with a cleaning solution. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a variable precision volumetric bio-3D printing system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a movable cover and a filter module according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a servo motor and a movable cover according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the first sliding mechanism and projection module according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures 1. Printer housing; 2. Projection module; 21. First sliding mechanism; 3. Printing module; 31. Printing container; 32. Movable cover; 321. Rotating rod; 322. Servo motor; 323. Output shaft; 324. Sealing ring; 4. Ink supply mechanism; 41. Ink nozzle; 42. Ink storage box; 43. Third sliding mechanism; 5. Filter module; 51. Screen; 52. Recycling box; 511. First mounting part; 513. Second mounting part; 6. Printing rotation mechanism; 61. Connecting frame; 62. Fixed bearing; 63. Hollow turntable; 7. High-resolution lens assembly; 71. Second sliding mechanism. Detailed Implementation

[0019] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0020] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the orientation in the assembled and used state. "Inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] A brief explanation of volumetric bioprinting technology: Volumetric bioprinting is an application of Computer Axial Lithography (CAL) in the field of biological tissue printing. Based on Stereolithography (SLA) / Digital Light Processing (DLP) technology, it projects calculated dynamic light patterns from multiple angles onto a rotating printing container 31. The curing light emitted from these dynamic patterns irradiates the photosensitive biomaterial (bio-ink) from different angles within the printing container 31, accumulating light energy at the intersections of these light rays. By controlling the projected dynamic light pattern, the accumulated light energy in only the designated area of ​​the three-dimensional structure to be printed within the photosensitive biomaterial reaches a critical value, thus causing curing. Therefore, volumetric bioprinting technology can achieve one-time integral molding of the printed structure. The dynamic light pattern can be generated using reverse engineering techniques from Computed Tomography (CT).

[0023] like Figures 1-4 As shown, the present invention provides a variable precision volumetric bio-3D printing system, including a controller, a printer housing 1, and a projection module 2, a printing module 3, and an ink supply mechanism 4 disposed in the printer housing 1.

[0024] The printing module 3 includes a light-transmitting cylindrical printing container 31 and a printing rotation mechanism 6 that drives it to rotate around an axis. The projection module 2 is mounted via a first sliding mechanism 21 and is controlled by the controller to move in a direction parallel to the axis of the printing container 31.

[0025] The controller is configured to coordinate the control of the first sliding mechanism 21 and the projection module 2, so that when the projection module 2 moves to different height positions, it switches the projection of two-dimensional image sequences with different resolutions or different image contents corresponding to each position to the rotating printing container 31, thereby realizing variable precision printing of three-dimensional biological structures.

[0026] When printing using this variable precision volumetric bio-3D printing system, the ink supply mechanism 4 adds bio-ink to the printing container 31 from directly above it. The controller controls the printing container 31 to rotate at a constant speed. As the printing container 31 rotates, the projection module 2 switches its projected two-dimensional image according to the rotation phase change of the printing container 31 to solidify the bio-ink and form the desired bio-structure.

[0027] By coordinating the control of the first sliding mechanism 21 and the projection module 2, the system can achieve different printing accuracies at different heights or axial regions of the three-dimensional structure during a single printing process. This is achieved by changing the axial position of the projection module 2 and synchronously switching the two-dimensional image sequence with corresponding resolution or image content. For example, when printing liver tissue with a fine capillary network and larger blood vessels, high-resolution projection can be used in the capillary region, while standard-resolution projection can be used in the larger blood vessel region to ensure the fidelity of the forming of key microstructures.

[0028] The technical solution of this invention overcomes the limitations of fixed precision in existing technologies. It enables high-resolution curing of complex and intricate areas of three-dimensional biological structures in a single print run, while lower-resolution rapid molding of macroscopic support areas, perfectly balancing printing precision and efficiency. This avoids the inefficient practice of using the highest resolution throughout the entire process to accommodate local fine features, significantly shortening the overall printing time for large-scale complex structures and saving computational resources. Furthermore, this technical solution avoids the inefficient practice of using the highest resolution projection for the entire large structure in pursuit of high local precision. Using an appropriate resolution for non-critical areas effectively reduces the amount of data in the projected image and the required computational resources, while ensuring the quality of critical areas and shortening the overall printing time for large-scale structures.

[0029] In some embodiments, the top opening of the printing container 31 allows the ink supply mechanism 4 to add bio-ink into it, and the bottom end of the printing container 31 is provided with a movable cover 32, which can open or close the bottom opening of the printing container 31. The filter module 5 is located directly below the printing container 31. When the controller controls the movable cover 32 to open, the filter module 5 can receive and separate the bio-ink and biological structures flowing out from the bottom opening of the printing container 31 to recover the remaining bio-ink from printing.

[0030] In some embodiments, the printer housing 1 of the volumetric bio-3D printing system is provided with a transparent observation window that can be opened and closed. When adjustments to components such as the printing container 31 are required, the operator can open the observation window to perform the adjustments.

[0031] In some embodiments, the inner top wall of the printer housing 1 is provided with a HEPA filter, which has an extremely high filtration effect on particles with a diameter of 0.3 micrometers (µm) and can efficiently remove tiny particles inside the printer housing 1.

[0032] In some embodiments, the inner top wall of the printer housing 1 is also provided with a sterilization mechanism, which may be an ultraviolet lamp or an ozone sterilizer, etc.

[0033] like Figure 2 As shown, in some embodiments of the present invention, the filter module 5 includes a screen 51 and a recycling box 52. The top of the recycling box 52 has a recycling opening. The screen 51 is detachably connected to the top of the recycling box 52 through a first mounting structure and can cover the recycling opening.

[0034] Specifically, when the movable cover 32 at the bottom of the printing container 31 is opened, the filter module 5 located below the printing container 31 can collect the bio-ink and bio-structure flowing out of the printing container 31. During this process, the bio-ink can be filtered through the screen 51 and stored in the recycling box 52, while the bio-structure and solidified particles mixed in with the bio-ink can be left on the screen 51.

[0035] In some embodiments, the screen 51 is configured to be elastic, so that when a biological structure falls onto the surface of the screen 51, the elastic screen 51 can provide a moderate buffering force to the biological structure, thereby effectively preventing the biological structure from being damaged during contact with the screen 51 and ensuring its integrity and availability.

[0036] In some embodiments of the present invention, the first mounting structure includes a first mounting portion 511 extending vertically around the inner wall of the recycling box 52 and a second mounting portion 513 extending horizontally outward from the top of the first mounting portion 511. The first mounting portion 511 can fit against the inner wall of the top of the recycling box 52, and the bottom of the second mounting portion 513 can press against the top surface of the recycling box 52.

[0037] Specifically, through the first mounting structure, the operator can easily remove the screen 51 from the top of the recycling box 52, and similarly, can quickly install the screen 51 into the recycling box 52. It should be clarified that the description "outward" refers to extending from the center of the recycling box 52 towards its peripheral wall.

[0038] like Figure 2 and Figure 3As shown, in some embodiments of the present invention, the movable cover 32 is provided with a rotating rod 321. The movable cover 32 is rotatably connected to the bottom end of the printing container 31 via the rotating rod 321. A servo motor 322 is also installed at the bottom end of the printing container 31. The output shaft 323 of the servo motor 322 is coaxially connected to the rotating rod 321 so as to drive the movable cover 32 to rotate.

[0039] Specifically, the servo motor 322 is connected to the controller via a signal. Under the control of the controller, the output shaft 323 of the servo motor 322 can drive the rotating rod 321 to rotate, so that the movable cover 32 can open or seal the opening at the bottom of the printing container 31.

[0040] In some embodiments, a sealing ring 324 is provided between the movable cover 32 and the printing container 31 to ensure the sealing of the bottom of the printing container 31 during printing.

[0041] In some embodiments of the present invention, the projection module 2 is mounted on the inner wall of the printer housing 1 via a first sliding mechanism 21. Under the control of the controller, the first sliding mechanism 21 can drive the projection module 2 to reciprocate in a direction parallel to the axis of the printing container 31. At the same time, the projection module 2 can switch its projected two-dimensional image according to the change of its height to irradiate the bio-ink that is cured at different heights in the printing container 31.

[0042] Specifically, when printing some slender biological structures, they can be printed in segments according to length. After one segment of the biological structure is printed, the projection module 2 can move to the projection height corresponding to the next segment under the drive of the first sliding mechanism 21, and switch the projection image to print that segment of the biological structure.

[0043] In some embodiments, the first sliding mechanism 21 is an electric slide rail. Those skilled in the art can choose other suitable forms of the first sliding mechanism 21 as needed, and the present invention does not impose any limitations.

[0044] In some embodiments of the present invention, the ink supply mechanism 4 includes multiple ink supply units, each including an ink supply pump, an ink storage box 42, an ink conduit, and an ink nozzle 41. The ink supply pump can transfer the bio-ink stored in the ink storage box 42 to the ink nozzle 41 through the ink conduit. The ink nozzle 41 is located above the top opening of the printing container 31 so as to add bio-ink to the printing container 31.

[0045] Specifically, multiple ink supply units can hold different types of bio-inks to meet complex printing requirements.

[0046] In some embodiments of the present invention, the ink supply mechanism 4 further includes a third sliding mechanism 43, through which all ink nozzles 41 can move vertically to approach or move away from the top opening of the printing container 31.

[0047] Specifically, when ink needs to be injected, the third sliding mechanism 43 drives the ink supply mechanism 4 to approach the top opening of the printing container 31. After ink injection is complete, the ink supply mechanism 4 moves away from the printing container 31 to make room for the printing container 31. In addition, when disassembling the printing container 31, the position of the ink supply mechanism 4 can be adjusted to make disassembly of the printing container 31 more convenient.

[0048] In some embodiments of the present invention, a printing rotation mechanism 6 is provided inside the printer housing 1. The printing container 31 is rotatably mounted on the inner wall of the printer housing 1 through the printing rotation mechanism 6. The printing rotation mechanism 6 includes a connecting frame 61 and a fixed bearing 62 and a hollow turntable 63 respectively provided at the top and bottom ends of the connecting frame 61. The bottom end of the printing container 31 passes through the through hole of the hollow turntable 63 and can be fixedly connected to the hollow turntable 63 by a set screw. The top end of the printing container 31 is rotatably connected to the fixed bearing 62.

[0049] Specifically, the two ends of the printing container 31 are rotatably connected to the connecting frame 61, which effectively ensures the stability of the printing container 31 during rotation.

[0050] In some embodiments of the present invention, the projection module 2 is provided with a high-resolution lens assembly 7, which is detachably connected to the projection lens of the projection module 2. The light source emitted from the projection lens can illuminate the printing container 31 after passing through the high-resolution lens assembly 7, so as to improve the resolution of the two-dimensional image projected by the projection module 2.

[0051] Specifically, by setting up a high-resolution lens assembly 7, the projection resolution can be improved, thereby enabling higher printing accuracy for certain areas of the biological structure.

[0052] In some embodiments, the high-resolution lens assembly 7 includes a high-NA lens, which improves the resolution and light-gathering capability of the optical system, thereby improving print quality. In some embodiments, the high-NA lens and the projection lens are detachably connected via magnetic attraction. In other embodiments, the high-NA lens and the projection lens are detachably connected via a threaded structure.

[0053] In some embodiments of the present invention, a second sliding mechanism 71 is provided inside the printer housing 1, and the connecting frame 61 is movably mounted on the inner wall of the printer housing 1 through the second sliding mechanism 71; driven by the second sliding mechanism 71, the connecting frame 61 can drive the printing container 31 to reciprocate along a direction parallel to the projection optical axis of the projection module 2, so as to adapt to the focal length change of the two-dimensional image modulated by the high-resolution lens assembly 7.

[0054] It should be noted that the projection optical axis refers to the central path of light propagation during the projection process.

[0055] In some embodiments, the precise control of injecting bio-ink into each region of the printing container 31 can be achieved through the cooperation of the second sliding mechanism 71 and the printing rotation mechanism 6, enabling the integrated printing of heterogeneous materials. First, when the second sliding mechanism 71 is stationary and the printing rotation mechanism 6 rotates the printing container 31, the ink nozzle 41 in a fixed position can control the injection of bio-ink into a cylindrical region of the printing container 31. The parameters of the cylindrical region are related to the position of the ink nozzle 41 and the diameter of the ejected water column; the difference between the inner and outer diameters of the cylindrical region is approximately equal to the diameter of the water column ejected by the ink nozzle 41. Furthermore, when the second sliding mechanism 71 moves, the printing rotation mechanism 6 enables precise ink injection at each point on the ink injection surface, which is a plane perpendicular to the axis of the printing container 31. It should be noted that precise ink injection relies on the high viscosity of the bio-ink. Through precise control of the ink injection position and multiple ink supply units by the controller, different regions of the printing container 31 can accommodate different types of bio-ink to meet the printing requirements of heterogeneous parts.

[0056] Specifically, when using this volumetric bio-3D printing system, the ink supply mechanism 4 adds bio-ink to the printing container 31 from directly above it. The controller controls the printing container 31 to rotate at a constant speed. As the printing container 31 rotates, the projection module 2 switches its projected two-dimensional image according to the rotation phase change of the printing container 31 to solidify the bio-ink and form the desired biological structure. When printing is complete, the controller controls the movable cover 32 to open, allowing the filter module 5 to receive and separate the bio-ink flowing out from the bottom opening of the printing container 31 and the formed biological structure, recovering the remaining bio-ink and processing it for subsequent use. The constructed biological structure is then removed from the filter module 5 for further processing or cultivation. Therefore, the volumetric bio-3D printing system of this invention, through the coordinated operation of the printing container 31 and the filter module 5, achieves the collection of remaining bio-ink during the printing process. This collected bio-ink can be reused after processing, reducing the application cost of volumetric bio-3D printing technology.

[0057] Another aspect of the present invention provides a volumetric biological 3D printing method, which includes the following steps: S1, establishing a projection model, performing tomographic scanning on the target printed object to obtain a two-dimensional image sequence, and converting the two-dimensional image sequence into a three-dimensional digital projection model through holographic reconstruction technology; S2, ink injection, injecting biological ink into the printing container 31 through the ink supply mechanism 4; S3, projection curing, the projection module 2 projects curing light onto the rotating printing container 31 according to the three-dimensional digital projection model; S4, removal and cleaning, after the biological structure has been cured and formed, the printing rotation mechanism 6 is closed and the bottom opening of the printing container 31 is opened, allowing the biological structure and the remaining biological ink to flow out to the filter module 5, the remaining biological ink flows through the screen 51 into the recycling box 52 for recycling and reuse, the biological structure is left on the screen 51, and the biological structure is cleaned with a cleaning solution.

[0058] In some embodiments, four bio-inks were used for printing. Bio-ink A formulation included 15% polyethylene glycol diacrylate (PEGDA) (600), 0.05% phenyl-2,4,6-trimethylbenzoyl lithium phosphinate (LPA) initiator, 1.5% sodium carboxymethyl cellulose, and 0.01% tartrazine, with water as the solvent. Bio-ink B formulation included 10% 1,6-hexanediol diacrylate (HDDA), 0.05% phenyl-2,4,6-trimethylbenzoyl lithium phosphinate (LPA) initiator, and 1.5% sodium alginate, with water as the solvent. Bio-ink C formulation included 0.05% phenyl-2,4,6-trimethylbenzoyl lithium phosphinate (LPA) initiator, 1.5% sodium methacrylamide hyaluronic acid, and 0.01% carmine water-soluble pigment, with water as the solvent. The bio-ink D formulation includes 12% dipentaerythritol hexaacrylate (DPHA), 0.05% phenyl-2,4,6-trimethylbenzoyl lithium phosphinate (LAP) initiator, 2.5% sodium hyaluronate, and 0.01% green water-soluble pigment, with water as the solvent. Under the control of the controller, the ink supply mechanism 4 adds the four bio-inks to the target positions of the printing container 31, followed by projection curing. The projection module 2 projects the curing light onto the rotating printing container 31 according to a three-dimensional digital projection model. After printing is completed, the controller controls the movable cover 32 to open, allowing the bio-ink and biological structure flowing from the bottom opening of the printing container 31 to flow to the filter module 5 for separation.

[0059] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0060] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0061] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A variable-precision volumetric bio-3D printing system, characterized in that, It includes a controller, a printer housing (1), and a projection module (2), a printing module (3), and an ink supply mechanism (4) disposed in the printer housing (1). The printing module (3) includes a light-transmitting cylindrical printing container (31) and a printing rotation mechanism (6) that drives it to rotate around an axis. The projection module (2) is mounted via a first sliding mechanism (21) and controlled by the controller to move in a direction parallel to the axis of the printing container (31). The controller is configured to coordinate the control of the first sliding mechanism (21) and the projection module (2) so that when the projection module (2) moves to different height positions, it switches the projection of two-dimensional image sequences with different resolutions or different image contents corresponding to each position to the rotating printing container (31), thereby realizing variable precision printing of three-dimensional biological structures.

2. The variable precision volumetric bio-3D printing system according to claim 1, characterized in that, The projection module (2) is provided with a high-resolution lens assembly (7) in the projection light path. The high-resolution lens assembly (7) is detachably connected to the projection module (2). The light source emitted from the projection lens can illuminate the printing container (31) after passing through the high-resolution lens assembly (7) to improve the resolution of the projected image.

3. The variable precision volumetric bio-3D printing system according to claim 2, characterized in that, The printing rotation mechanism (6) is installed inside the printer housing (1) via the second sliding mechanism (71); the controller is configured to control the second sliding mechanism (71) to drive the printing container (31) to reciprocate along a direction parallel to the projection optical axis of the projection module (2) when the high-resolution lens assembly (7) is installed, so as to adapt to the focal length change of the two-dimensional image modulated by the high-resolution lens assembly (7) and ensure projection clarity.

4. The variable precision volumetric bio-3D printing system according to claim 1, characterized in that, The ink supply mechanism (4) includes multiple independent ink supply units, each including an ink pump, an ink reservoir (42), an ink conduit, and an ink nozzle (41). The ink pump can transfer the bio-ink stored in the ink reservoir (42) to the ink nozzle (41) through the ink conduit. The ink nozzle (41) is located above the top opening of the printing container (31) so as to add bio-ink to the printing container (31).

5. The variable precision volumetric bio-3D printing system according to claim 4, characterized in that, The ink supply mechanism (4) also includes a third sliding mechanism (43) through which all the ink nozzles (41) can move vertically to approach or move away from the top opening of the printing container (31).

6. The variable precision volumetric bio-3D printing system according to claim 1, characterized in that, It also includes a filter module (5), which includes a screen (51) and a recycling box (52). The recycling box (52) has a recycling opening at the top. The screen (51) is detachably connected to the top of the recycling box (52) through a first mounting structure and can cover the recycling opening.

7. The variable precision volumetric bio-3D printing system according to claim 6, characterized in that, The first mounting structure includes a first mounting portion (511) extending vertically around the inner wall of the recycling box (52) and a second mounting portion (513) extending horizontally outward from the top of the first mounting portion (511). The first mounting portion (511) can fit against the inner wall of the top of the recycling box (52), and the bottom of the second mounting portion (513) can press against the top surface of the recycling box (52).

8. The variable precision volumetric bio-3D printing system according to claim 1, characterized in that, The bottom end of the printing container (31) is provided with a movable cover (32), which can open or close the bottom opening of the printing container (31). The movable cover (32) is provided with a rotating rod (321). The movable cover (32) is rotatably connected to the bottom end of the printing container (31) through the rotating rod (321). The bottom end of the printing container (31) is also equipped with a servo motor (322). The output shaft (323) of the servo motor (322) is coaxially connected to the rotating rod (321) so as to drive the movable cover (32) to rotate. When the movable cover (32) is opened, the solidified biological structure and the unsolidified remaining biological ink can flow out together to the filter module (5), and the filter module (5) separates the biological structure from the remaining biological ink to achieve ink recycling.

9. The variable precision volumetric bio-3D printing system according to claim 1, characterized in that, The printing rotation mechanism (6) includes a connecting frame (61) and fixed bearings (62) and a hollow turntable (63) respectively located at the top and bottom of the connecting frame (61). The bottom end of the printing container (31) passes through the through hole of the hollow turntable (63) and can be fixedly connected to the hollow turntable (63) by a set screw. The top end of the printing container (31) is rotatably connected to the fixed bearing (62).

10. A method for volumetric bio-3D printing with variable precision, characterized in that, The method is implemented based on the variable precision volumetric bio-3D printing system according to any one of claims 1-9, and includes the following steps: S1. Establish a projection model, perform tomographic scanning on the target printed object to obtain a two-dimensional image sequence, and convert the two-dimensional image sequence into a three-dimensional digital projection model through holographic reconstruction technology. S2, Ink injection: Bio-ink is injected into the printing container (31) through the ink supply mechanism (4); S3, Projection curing, the projection module (2) projects curing light onto the rotating printing container (31) according to the three-dimensional digital projection model. S4, after cleaning and solidification of the biological structure, close the printing rotation mechanism (6) and open the bottom opening of the printing container (31) so that the biological structure and the remaining biological ink flow out to the filter module (5). The remaining biological ink flows through the screen (51) into the recycling box (52) for recycling and reuse. The biological structure is left on the screen (51) and cleaned with cleaning solution.

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