Volume photocuring three-dimensional printing method and device based on oxygen permeation interface dynamic oxygen inhibition control

Abstract

The invention provides a volume photocuring three-dimensional printing method and device based on oxygen permeation interface dynamic oxygen inhibition control, and relates to the technical field of photocuring additive manufacturing. The volume photocuring three-dimensional printing method comprises the following steps that a resin cavity is prepared, the closed container is formed by compounding an oxygen permeable membrane and a transparent rigid material; establishing an oxygen inhibition layer: maintaining air or oxygen-containing atmosphere outside the closed container, so that oxygen continuously permeates into a resin boundary area through the oxygen permeation membrane to form the stable oxygen inhibition layer; volume light field projection: projecting a projection image generated by a computed tomography algorithm into the resin volume by adopting a calculation axial photoetching type multi-angle projection mode to realize multi-angle rotary projection exposure; edge curing is delayed through the boundary oxygen inhibition layer, the problem that the boundary light dosage of traditional volume printing is not uniform is solved, the final forming volume is enlarged by 1.5-3 times compared with the prior art, and the size bottleneck of volume light curing printing is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of photopolymer additive manufacturing technology, and in particular to a volumetric photopolymer 3D printing method and apparatus based on dynamic oxygen suppression control of oxygen-permeable interfaces. Background Technology

[0002] Existing volumetric photopolymerization printing technologies, represented by computational axial lithography and volumetric holographic photopolymerization printing, work on the core principle of simultaneously accumulating light dose within the resin volume through multi-angle projected light fields to achieve rapid and synchronous curing of three-dimensional structures. These technologies can complete the printing of complete three-dimensional structures in seconds to sub-seconds, offering significant advantages in printing speed and spatial resolution. Meanwhile, traditional continuous liquid surface printing technology utilizes a polydimethylsiloxane oxygen-permeable membrane at the bottom of the resin tank, employing oxygen permeation to create a stable "dead zone," preventing resin adhesion to the substrate and enabling continuous printing. However, existing technologies still have many shortcomings that urgently need to be addressed: On the one hand, volumetric photopolymerization printing generally faces the problem of limited curing volume. Due to light scattering, refraction, and multiple reflections, the light dose distribution at the resin boundary is uneven, easily resulting in "over-cured" or "under-cured" areas, which in turn limits the printing size. Once the boundary area cures, it loses the free flow of the resin, hindering the light transmission path and affecting the subsequent curing volume and accuracy. For water-containing bioprintable systems such as PEGDA and GelMA, the oxygen content in the closed container is rapidly depleted, making it difficult to form a photopolymerization inhibition layer, resulting in a rough curing interface and difficulty in demolding. On the other hand, the oxygen control of CLIP technology only acts on a single planar interface, which cannot establish a three-dimensional oxygen gradient in volumetric printing mode, nor can it adjust the gradual extension of the curing boundary with the exposure process, thus failing to meet the three-dimensional molding requirements of volumetric printing. Therefore, this invention proposes a volumetric photopolymerization three-dimensional printing method and apparatus based on dynamic oxygen suppression control of the oxygen-permeable interface to solve the problems existing in the prior art. Summary of the Invention

[0003] To address the aforementioned issues, this invention proposes a volumetric photopolymerization 3D printing method and apparatus based on dynamic oxygen suppression control at the oxygen-permeable interface. By delaying edge curing through a boundary oxygen suppression layer, the uneven boundary light dose problem of traditional volumetric printing is avoided, resulting in a final formed volume that is 1.5–3 times larger than existing technologies, effectively solving the size bottleneck of volumetric photopolymerization printing.

[0004] To achieve the objectives of this invention, the invention is implemented through the following technical solution: a volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control of the oxygen-permeable interface, comprising the following steps: S1: Resin chamber preparation: Light-curing resin is filled into a closed container with at least one side being an oxygen-permeable membrane. The closed container is composed of an oxygen-permeable membrane and a transparent rigid material. S2: Oxygen inhibition layer establishment: Maintaining an air or oxygen-containing atmosphere outside the sealed container allows oxygen to continuously permeate through the oxygen-permeable membrane to the resin boundary area, forming a stable oxygen inhibition layer. S3: Volumetric light field projection: Using a computational axial lithography-based multi-angle projection method, the projection image generated by the computer tomography algorithm is projected into the resin volume to achieve multi-angle rotational projection exposure; S4: Epitaxial curing process: In the initial stage of exposure, the central region of the resin cures first, while the edge region remains liquid due to oxygen inhibition; as exposure continues, the curing front gradually advances from the center to the boundary, forming an onion-layer continuous epitaxial curing structure. S5: Printed Part Extraction: After exposure, the uncured resin is removed to obtain a complete three-dimensional solid model.

[0005] A further improvement is that, in S1, the oxygen-permeable membrane is one of the following oxygen-permeable polymer materials: polydimethylsiloxane (PDMS), Teflon AF, Hyflon, or fluorosilicone copolymer.

[0006] A further improvement is that the thickness of the oxygen-permeable membrane in S1 is 0.1–1.0 mm.

[0007] A further improvement is that, in S1, the photocurable resin includes an aqueous photopolymerization system composed of one or more of PEGDA, GelMA, and HEMA, or a traditional acrylate photocurable resin.

[0008] A further improvement is that: in S1, bioactive components or cells are added to the photocurable resin.

[0009] A further improvement is that: in S2, the oxygen-containing atmosphere is air or pure oxygen, and the oxygen partial pressure outside the container is adjusted by a gas flow control device, with the oxygen partial pressure range being 0.21–1.0 atm of standard atmospheric pressure.

[0010] A further improvement is that, in S2, the thickness of the oxygen suppression layer can be controllably adjusted from 15 to 65 μm by adjusting the thickness of the oxygen-permeable membrane, the oxygen partial pressure, and the exposure light intensity.

[0011] A further improvement is made in S3, where the wavelength of the light source for projection exposure is 365–405 nm, and the light intensity is 5–15 mW / cm². 2 .

[0012] A further improvement is that, in S3, the angular resolution of the multi-angle rotation projection is 0.5–2° / frame, and the total exposure time is 30–60s.

[0013] A volumetric photopolymerization 3D printing device based on dynamic oxygen suppression control of an oxygen-permeable interface includes an optical projection module, an oxygen-permeable printing cavity, a gas supply and control module, and a coordinated control system. The optical projection module is used to output a multi-angle rotating projection light field, and the wavelength, light intensity, and projection image sequence of the light source can be adjusted. The oxygen-permeable printing cavity is made of a transparent rigid frame and an oxygen-permeable membrane, and the oxygen-permeable membrane constitutes at least one sidewall or bottom surface of the cavity. The gas supply and control module includes an oxygen supply pipeline, a flow control device, a pressure regulator, and a gas distributor, used to maintain a stable concentration and pressure of the oxygen-containing atmosphere outside the oxygen-permeable membrane; the coordination and control system is used to synchronously coordinate the exposure parameters of the optical projection module and the oxygen supply parameters of the gas supply and control module to ensure a stable advancement rate of the curing front.

[0014] The beneficial effects of this invention are as follows: 1. This invention delays edge curing by using a boundary oxygen suppression layer, avoiding the problem of uneven boundary light dose in traditional volumetric printing, and increasing the final molded volume by 1.5–3 times compared to existing technologies, effectively solving the size bottleneck of volumetric photopolymerization printing.

[0015] 2. The boundary liquid oxygen suppression layer of this invention has a self-leveling effect on the cured surface, which can eliminate delamination marks and edge roughness defects, making the surface of the printed part smooth and uniform; the onion layer epitaxial curing mode realizes continuous growth from the center to the edge, no longer restricted by the boundary curing lock of traditional volume printing, and the integrity of the formed structure is higher.

[0016] 3. This invention can precisely control the thickness of the oxygen inhibition layer by adjusting the thickness of the oxygen-permeable membrane, the oxygen partial pressure, and the exposure dose, adapting to different size and precision requirements; the oxygen-permeable interface avoids overheating during the printing process, reduces phototoxicity, and the formation of the oxygen inhibition layer does not require additional chemical additives, making it cell-friendly and particularly suitable for bioprintable material systems such as PEGDA and GelMA. Attached Figure Description

[0017] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0018] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0019] Example 1 according to Figure 1 As shown, this embodiment proposes a volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at the oxygen-permeable interface, including the following steps: S1: Resin Chamber Preparation: A sealed container with at least one oxygen-permeable membrane is filled with photocurable resin. The sealed container is composed of an oxygen-permeable membrane and a transparent rigid material. The oxygen-permeable membrane is one of the following oxygen-permeable polymers: polydimethylsiloxane (PDMS), Teflon AF, Hyflon, or fluorosilicone copolymers. The thickness of the oxygen-permeable membrane is 0.1–1.0 mm. The photocurable resin includes an aqueous photopolymer system composed of one or more of PEGDA, GelMA, and HEMA, or a traditional acrylate photocurable resin. Bioactive components or cells are added to the photocurable resin. Specific oxygen-permeable membrane materials possess both excellent oxygen permeability and chemical stability, maintaining oxygen permeability efficiency over a long period and avoiding reactions with the resin that could affect printing results. The diverse selection of resin systems and the compatible design of bioactive components meet both the high-precision printing needs of industrial applications and the cell loading requirements of bio-tissue engineering. S2: Oxygen Inhibition Layer Establishment: An air or oxygen-containing atmosphere is maintained outside the sealed container, allowing oxygen to continuously permeate through the oxygen-permeable membrane to the resin boundary area, forming a stable oxygen inhibition layer. The oxygen-containing atmosphere is air or pure oxygen, and the oxygen partial pressure outside the container is adjusted by a gas flow control device, with the oxygen partial pressure range being 0.21–1.0 atm (standard atmospheric pressure). The thickness of the oxygen inhibition layer is controllably adjustable from 15–65 μm by adjusting the thickness of the oxygen-permeable membrane, the oxygen partial pressure, and the exposure light intensity. Precise control of the oxygen partial pressure enables on-demand matching of the oxygen inhibition layer formation rate and thickness, adaptable to the polymerization reaction rate of different resins. The wide adjustable range of 15–65 μm provides flexible adaptation space for balancing the edge accuracy of printed parts and the curing progress rate, taking into account both large-volume molding and detail reproduction. S3: Volumetric Light Field Projection: Employing a computational axial lithography-based multi-angle projection method, the projection image generated by the computed tomography algorithm is projected into the resin volume, achieving multi-angle rotational projection exposure; the light source wavelength for projection exposure is 365–405nm, and the light intensity is 5–15mW / cm². 2 The angular resolution of the multi-angle rotating projection is 0.5–2° / frame, and the total exposure time is 30–60s; the wavelength is 365–405nm and the power consumption is 5–15mW / cm². 2 The combination of light intensity can ensure efficient resin polymerization while reducing phototoxic damage to bioactive components or cells; the angular resolution of 0.5-2° / frame ensures the detail reproduction of complex three-dimensional structures, and the reasonable exposure time of 30-60s balances molding efficiency and structural stability. S4: Epitaxial Curing Process: In the initial stage of exposure, the central region of the resin cures first, while the edge region remains liquid due to oxygen inhibition. As exposure continues, the curing front gradually advances from the center to the boundary, forming an onion-layer continuous epitaxial curing structure. The progressive curing from the center to the edge effectively avoids the boundary over-curing problem of traditional volume printing, significantly improving the molding integrity of large-size structures. The onion-layer continuous epitaxial structure ensures uniform stress at the curing front, reducing defects such as cracking and delamination caused by internal stress concentration, and improving the mechanical properties of the printed parts. S5: Printed Part Extraction: After exposure, the uncured resin is discharged, resulting in a complete 3D solid model. The direct discharge of uncured resin simplifies the post-processing steps and avoids scratch damage to the surface of the printed part during demolding. Combined with the self-leveling effect of the oxygen-inhibiting layer, the extracted printed part can achieve a smooth surface without additional polishing, significantly improving production efficiency.

[0020] A volumetric photopolymerization 3D printing device based on dynamic oxygen suppression control of an oxygen-permeable interface includes an optical projection module, an oxygen-permeable printing cavity, a gas supply and control module, and a coordinated control system. The optical projection module is used to output a multi-angle rotating projection light field, and the wavelength, intensity, and projection image sequence of the light source can be adjusted. The oxygen-permeable printing cavity is made of a transparent rigid frame and an oxygen-permeable membrane, with the oxygen-permeable membrane forming at least one sidewall or bottom surface of the cavity. The multi-parameter adjustable characteristics of the optical projection module enable it to adapt to different combinations of oxygen-permeable membranes and resins, expanding the application range of the device. The composite structure design of the oxygen-permeable printing cavity balances structural rigidity and oxygen permeability efficiency, ensuring the stability of the cavity and the continuity of the oxygen suppression layer during the printing process. The gas supply and control module includes an oxygen supply pipeline, a flow control device, a pressure regulator, and a gas distributor, used to maintain a stable concentration and pressure of the oxygen-containing atmosphere outside the oxygen-permeable membrane. The coordination control system is used to synchronously coordinate the exposure parameters of the optical projection module and the oxygen supply parameters of the gas supply and control module, ensuring a stable advancement rate of the curing front. The pressure-flow dual-regulation design of the gas supply and control module achieves long-term stability of the oxygen atmosphere, avoiding molding defects caused by fluctuations in the oxygen suppression layer. The synchronous adjustment function of the coordination control system enables real-time matching of exposure and oxygen supply parameters, ensuring uniform advancement of the curing front and improving the dimensional accuracy and batch consistency of the printed parts.

[0021] Example 2 according to Figure 1 As shown, this embodiment proposes a volumetric photopolymerization 3D printing method and apparatus based on dynamic oxygen suppression control at the oxygen-permeable interface, including the following steps: Material system UV-curable resin: PEGDA (molecular weight 700) concentration 20wt%; Photoinitiator: LAP (0.1wt%).

[0022] Device parameters Oxygen-permeable printing chamber: The inner diameter is 30mm, and the bottom and side walls are made of 0.5mm thick PDMS oxygen-permeable membrane. The frame is made of transparent acrylic material. Gas supply: Air (21% oxygen content) is introduced outside the membrane, and the pressure is maintained at atmospheric pressure without additional airflow drive.

[0023] Printing conditions Optical projection module: 405nm LED light source, average light intensity 10mW / cm² 2 Total exposure time 40s, rotation angle resolution 1° / frame; Coordinated control: Exposure and gas supply start synchronously, eliminating the need for mid-process parameter adjustments.

[0024] result The thickness of the oxygen-inhibiting layer at the resin boundary is approximately 30 μm; The printing volume is 2.1 times larger than that of ordinary glass containers (without oxygen-permeable membrane) printed by photopolymerization. The surface roughness of the printed part Ra≤0.8μm, with no obvious delamination or edge burrs.

[0025] Example 3 according to Figure 1 As shown, this embodiment proposes a volumetric photopolymerization 3D printing method and apparatus based on dynamic oxygen suppression control at the oxygen-permeable interface, including the following steps: Material system UV-curable resin: GelMA (10wt%); Photoinitiator: Irgacure2959 (0.05wt%).

[0026] Device parameters Oxygen-permeable printing chamber: PDMS oxygen-permeable membrane with a thickness of 1mm, and a transparent rigid frame made of quartz material; Gas supply: Pure oxygen is introduced outside the membrane at a flow rate of 0.1 L / min, and the pressure regulator maintains the external membrane pressure at 0.12 MPa.

[0027] Printing conditions Optical projection module: 405nm LED light source, light intensity 8mW / cm² 2 Total exposure time 50s, rotation angle resolution 1° / frame; Coordinated control: After 10 seconds of exposure, the oxygen flow rate was adjusted to 0.08 L / min to maintain a stable rate of advancement of the curing front.

[0028] result The oxygen inhibition layer is approximately 50 μm thick; The boundary liquid state is maintained for 8–10 seconds, and the solidification front advances at a uniform speed. The molding volume is 2.5 times larger than that of traditional volume printing, the interface is uniform and smooth, and there are no over-cured protrusions.

[0029] Example 4 according to Figure 1 As shown, this embodiment proposes a volumetric photopolymerization 3D printing method and apparatus based on dynamic oxygen suppression control at the oxygen-permeable interface, including the following steps: Experimental Objective The effect of oxygen-permeable membrane thickness and exposure light intensity on the thickness of the oxygen-inhibiting layer was verified.

[0030] Test parameters Oxygen-permeable membrane thickness gradient: 0.2mm, 0.5mm, 1.0mm (PDMS material); Exposure intensity gradient: 5mW / cm 2 10mW / cm 2 15mW / cm 2 (405nm light source); Resin system: PEGDA (20wt%) + LAP (0.1wt%); Gas environment: pure oxygen, flow rate 0.05 L / min.

[0031] result By detecting the oxygen suppression layer thickness (d_dz) under different parameter combinations, the following relationship was obtained: d_dz∝√(1 / I), that is, the oxygen suppression layer thickness is inversely proportional to the exposure light intensity; when the oxygen permeable film thickness increases, the oxygen suppression layer thickness increases linearly (0.2mm film corresponds to d_dz≈15μm, 1.0mm film corresponds to d_dz≈65μm), proving that the curing boundary position can be precisely adjusted by parameter combinations.

[0032] Validation data: Comparative test results under the same resin system and the same exposure time (40–50s): ; This invention delays edge curing through a boundary oxygen suppression layer, avoiding the uneven light dose problem at the boundary in traditional volumetric printing. This results in a final formed volume 1.5–3 times larger than existing technologies, effectively solving the size bottleneck of volumetric photopolymerization printing. Furthermore, the boundary liquid oxygen suppression layer has a self-leveling effect on the cured surface, eliminating delamination marks and edge roughness defects, resulting in a smooth and uniform printed surface. The onion-layer epitaxial curing mode achieves continuous growth from the center to the edge, no longer limited by the boundary curing lock-in of traditional volumetric printing, leading to higher structural integrity. Simultaneously, this invention allows for precise control of the oxygen suppression layer thickness by adjusting the oxygen permeability membrane thickness, oxygen partial pressure, and exposure dose, adapting to different size and precision requirements. The oxygen permeability interface avoids overheating during printing, reduces phototoxicity, and the oxygen suppression layer formation requires no additional chemical additives, making it cell-friendly and particularly suitable for bioprintable material systems such as PEGDA and GelMA.

[0033] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface, characterized in that, Includes the following steps: S1: Resin chamber preparation: Light-curing resin is filled into a closed container with at least one side being an oxygen-permeable membrane. The closed container is composed of an oxygen-permeable membrane and a transparent rigid material. S2: Oxygen inhibition layer establishment: Maintaining an air or oxygen-containing atmosphere outside the sealed container allows oxygen to continuously permeate through the oxygen-permeable membrane to the resin boundary area, forming a stable oxygen inhibition layer. S3: Volumetric light field projection: Using a computational axial lithography-based multi-angle projection method, the projection image generated by the computer tomography algorithm is projected into the resin volume to achieve multi-angle rotational projection exposure; S4: Epitaxial curing process: In the initial stage of exposure, the central area of ​​the resin cures first, while the edge area is inhibited by oxygen and remains in a liquid state; As exposure continues, the curing front gradually advances from the center to the boundary, forming an onion-layer-like continuous epitaxial curing structure; S5: Printed Part Extraction: After exposure, the uncured resin is removed to obtain a complete three-dimensional solid model.

2. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S1, the oxygen-permeable membrane is one of the following oxygen-permeable polymer materials: polydimethylsiloxane (PDMS), Teflon AF, Hyflon, or fluorosilicone copolymer.

3. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S1, the thickness of the oxygen-permeable membrane is 0.1–1.0 mm.

4. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S1, the photocurable resin includes an aqueous photopolymerization system composed of one or more of PEGDA, GelMA, and HEMA, or a traditional acrylate photocurable resin.

5. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S1, bioactive components or cells are added to the photocurable resin.

6. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S2, the oxygen-containing atmosphere is air or pure oxygen. The oxygen partial pressure outside the container is adjusted by a gas flow control device. The oxygen partial pressure range is 0.21–1.0 atm, which is the standard atmospheric pressure.

7. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S2, the thickness of the oxygen suppression layer can be controlled to be adjusted from 15 to 65 μm by adjusting the thickness of the oxygen-permeable membrane, the oxygen partial pressure, and the exposure light intensity.

8. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In step S3, the wavelength of the light source used for projection exposure is 365–405 nm, and the light intensity is 5–15 mW / cm². 2 .

9. The volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface according to claim 1, characterized in that: In S3, the angular resolution of the multi-angle rotation projection is 0.5–2° / frame, and the total exposure time is 30–60s.

10. A volumetric photopolymerization 3D printing apparatus based on dynamic oxygen suppression control at an oxygen-permeable interface, applied to the volumetric photopolymerization 3D printing method based on dynamic oxygen suppression control at an oxygen-permeable interface as described in any one of claims 1-9, characterized in that, It includes an optical projection module, an oxygen-permeable printing cavity, a gas supply and control module, and a coordinated control system. The optical projection module is used to output a multi-angle rotating projection light field, and the wavelength, light intensity, and projection image sequence of the light source can be adjusted. The oxygen-permeable printing cavity is made of a transparent rigid frame and an oxygen-permeable membrane, and the oxygen-permeable membrane constitutes at least one side wall or bottom surface of the cavity. The gas supply and control module includes an oxygen supply pipeline, a flow control device, a pressure regulator, and a gas distributor, used to maintain a stable concentration and pressure of the oxygen-containing atmosphere outside the oxygen-permeable membrane; the coordination and control system is used to synchronously coordinate the exposure parameters of the optical projection module and the oxygen supply parameters of the gas supply and control module to ensure a stable advancement rate of the curing front.

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