Dual-wavelength accelerated curing light-curing 3D printing method and apparatus

Abstract

This invention discloses a dual-wavelength accelerated curing photopolymerization 3D printing method and apparatus, relating to the field of additive manufacturing technology. It employs a dual-wavelength responsive photopolymerization ink, which comprises a polymerizable monomer, a photoinitiator sensitive to a first wavelength, a photosensitizer sensitive to a second wavelength, a singlet oxygen quencher, and a solvent. The photosensitizer is excited under second-wavelength light irradiation, converting ambient oxygen into singlet oxygen. The singlet oxygen quencher consumes singlet oxygen to reduce local oxygen concentration. The first and second wavelengths are spectrally orthogonal. This dual-wavelength accelerated curing photopolymerization 3D printing method and apparatus eliminates oxygen inhibition in localized low-oxygen environments, reduces exposure dose, and increases printing speed.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a dual-wavelength accelerated curing photopolymerization 3D printing method and equipment. Background Technology

[0002] Photopolymer 3D printing boasts advantages such as high forming accuracy and high speed, and is widely used in rapid manufacturing, biomedicine, and precision structural processing. However, in an atmospheric environment, oxygen has a strong inhibitory effect on free radical polymerization, known as the oxygen inhibition effect, which can lead to problems such as insufficient surface curing, slow curing speed, shallow curing depth, and decreased printing accuracy.

[0003] Existing technologies for overcoming oxygen inhibition have significant drawbacks: Inert atmosphere protection: requires a sealed chamber and nitrogen / argon gas supply, the equipment is complex and costly, and cannot be used in open bioprinting scenarios; Increasing light intensity or adding amine-based co-initiators can easily damage bioactive materials, reduce product stability, and fail to address oxygen inhibition at its root. Formula optimization: limited effect, difficult to balance speed and accuracy. Summary of the Invention

[0004] The purpose of this invention is to provide a dual-wavelength accelerated curing photopolymerization 3D printing method and equipment to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a dual-wavelength accelerated curing photopolymerization 3D printing method, employing a dual-wavelength responsive photopolymerization ink, wherein the ink comprises a polymerizable monomer, a photoinitiator sensitive to a first wavelength band, a photosensitizer sensitive to a second wavelength band, a singlet oxygen quencher, and a solvent; the photosensitizer is excited under irradiation with the second wavelength band light, converting ambient oxygen into singlet oxygen, and the singlet oxygen quencher is used to consume singlet oxygen to reduce the local oxygen concentration; the first wavelength band light and the second wavelength band light are orthogonal in spectrum.

[0006] Preferably, it includes the following steps: (1) Apply dual-wavelength responsive photocurable ink to the printing area in an oxygen-containing atmosphere; (2) Project the second-band light onto the target location of the printing area to excite the photosensitizer to produce singlet oxygen. The singlet oxygen is consumed by the singlet oxygen quencher, causing a local hypoxia zone to form at the target location. (3) Projecting first-band light onto the target position to excite the photoinitiator to generate active free radicals. The free radical polymerization reaction is accelerated in a low-oxygen environment, which makes the ink solidify and form quickly.

[0007] Preferably, steps (2) and (3) are executed sequentially or synchronously; when executed sequentially, the second band light is first projected for pre-oxygen consumption, and then the first band light is projected for curing; when executed synchronously, the second band light and the first band light are projected simultaneously.

[0008] Preferably, during sequential execution, the second-band light uses a planar projection pattern consistent with the current printed layer slice data to perform overall pre-oxygen consumption treatment on the target planar area.

[0009] Preferably, during synchronous execution, the illumination area of ​​the second band light is the same as or slightly smaller than the illumination area of ​​the first band light.

[0010] Preferably, the irradiation intensity and duration of the second-band light are configured to create an effective local hypoxia zone at the target location without causing thermal damage to the ink or non-specific side reactions.

[0011] Preferably, the first band light and the second band light are projected using a surface projection method or a volume projection method.

[0012] Preferably, when using volume projection, the first band light and the second band light form a three-dimensional spatial light field, which simultaneously achieves oxygen consumption and curing in the three-dimensional region inside the ink body.

[0013] Preferably, the oxygen-containing atmosphere is ambient air or an oxygen-containing gas environment that has an oxygen inhibition effect.

[0014] A dual-wavelength accelerated curing photopolymerization printing device is used to implement the aforementioned dual-wavelength accelerated curing photopolymerization 3D printing method. It includes: an ink container, a first light source system, a second light source system, a spatial light modulation system, a motion platform, and a control unit. The control unit is electrically connected to the first light source system, the second light source system, the spatial light modulation system, and the motion platform, and is used to coordinate and control each component to execute the printing process. The spatial light modulation system is a digital light processing chip, a liquid crystal spatial light modulator, a digital micromirror array, or a three-dimensional light field holographic modulation module. The first light source system and the second light source system are independent light sources, which are combined by a beam-combining optical element and modulated by the same spatial light modulation unit, or modulated by separate independent spatial light modulation units. The first light source system and the second light source system are switchable wavelength light sources, sharing the same spatial light modulation system, and the control unit controls the wavelength switching and projection timing.

[0015] Compared with the prior art, the beneficial effects of the present invention are: the dual-wavelength accelerated curing photopolymerization 3D printing method and equipment eliminate oxygen inhibition in local low oxygen, reduce exposure dose, and improve printing speed; reduce curing energy threshold, reduce stray light over-curing, resulting in sharper edges and higher resolution; the equivalent effect of an oxygen-free environment can be achieved in an open air environment, and the equipment is simple and low-cost; it is free of amine additives and high-energy damage, making it suitable for cell-loaded hydrogel bioprinting. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the photochemical mechanism of dual-wavelength accelerated curing photopolymerization 3D printing according to the present invention; Figure 2 This is a photorheological test diagram showing the accelerated curing effect of the present invention; Figure 3 This is a schematic diagram comparing the forming effects of conventional photopolymerization 3D printing and the dual-wavelength accelerated photopolymerization 3D printing of this invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1 Sequential exposure printing method based on DLP surface projection: This embodiment uses digital light processing (DLP) surface projection technology.

[0019] Equipment Configuration: The equipment integrates a 405nm DLP optical engine (first light source system) and a 635nm DLP optical engine (second light source system). The two optical engines are arranged vertically, and the projection surface is superimposed through a semi-transparent and semi-reflective mirror. The control unit can independently control the switching on and off of the two optical engines and the pattern.

[0020] Ink: A dual-wavelength responsive photocurable ink is used, which contains: 10% (w / v) PEGDA700 as a monomer, 0.05% (w / v) LAP as a photoinitiator sensitive to 405nm light, 0.002% (w / v) methylene blue as a photosensitizer sensitive to 635nm light, and 0.1% (w / v) L-histidine as a singlet oxygen quencher.

[0021] Printing process: (1) In open air, inject ink into a transparent trough.

[0022] (2) For the nth layer slice: The control unit first simultaneously turns on the 405nm DLP optical engine and the 635nm DLP optical engine to project the binarized image of the nth layer slice onto the entire printing plane for 5 seconds (light intensity 20mW / cm²). During this process, the ink in the projection area undergoes photocontrolled oxygen dissipation and synchronous photocuring.

[0023] (3) Raise the platform by one layer thickness (e.g., 100 μm) and repeat step (2) until printing is complete.

[0024] (4) Effect: Traditionally, it takes 10 seconds of irradiation with 405nm light to cure the ink. The solution provided by this invention shortens the total exposure time to 5 seconds, increases the speed by 50%, and significantly improves the accuracy of the printed parts.

[0025] Example 2 Synchronous Exposure Printing Method Based on Volumetric Projection: This embodiment uses Computer Axial Lithography (CAL) volumetric projection technology.

[0026] Equipment Configuration: The equipment adopts a typical CAL architecture, mainly consisting of a transparent cylindrical container that can rotate around an axis, a 405nm LED surface light source (first light source system), and a 635nm LED surface light source (second light source system). Each light source is equipped with an independent spatial light modulator (such as an LCD or DLP chip). The control unit synchronously coordinates the container's rotational movement and the sequential switching of the dual-wavelength projected images.

[0027] Ink: A dual-wavelength responsive photocurable ink is used, which contains: 10% (w / v) PEGDA700 as a monomer, 0.05% (w / v) LAP as a photoinitiator sensitive to 405nm light, 0.002% (w / v) methylene blue as a photosensitizer sensitive to 635nm light, and 0.1% (w / v) L-histidine as a singlet oxygen quencher.

[0028] Printing process: (1) Fill an open cylindrical glass bottle with ink.

[0029] (2) The control unit pre-calculates a series of two-dimensional image sequences projected from different angles based on the three-dimensional model. For each projection angle, the control unit controls the spatial light modulator to synchronously generate two matching patterns: one is a 405nm "cured image," corresponding to a slice of the target structure at that angle; the other is a 635nm "auxiliary oxygen-consuming image," whose pattern is exactly the same as or slightly smaller than the cured image. During container rotation, the dual-wavelength image sequence is synchronously projected onto the resin in the container. At each angle, the 635nm light pre- or synchronously dissipates oxygen in the target voxel region, and subsequently or simultaneously, the 405nm light initiates polymerization in a low-oxygen environment. Through the accumulation of light intensity from multi-angle projections, a complete three-dimensional structure is finally constructed in the ink in one step.

[0030] (3) After printing, the uncured ink is removed to obtain a complete three-dimensional structure.

[0031] (4) Results: Compared with traditional CAL single-wavelength printing, this method significantly improves printing speed and printing accuracy in air environments. Figure 3 ).

[0032] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A photopolymerization 3D printing method with dual-wavelength accelerated curing, characterized in that: A dual-wavelength responsive photocurable ink is used, comprising a polymerizable monomer, a photoinitiator sensitive to a first wavelength band, a photosensitizer sensitive to a second wavelength band, a singlet oxygen quencher, and a solvent; the photosensitizer is excited under irradiation with the second wavelength band light, converting ambient oxygen into singlet oxygen, and the singlet oxygen quencher is used to consume singlet oxygen to reduce the local oxygen concentration; the first wavelength band light and the second wavelength band light are orthogonal in spectrum.

2. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 1, characterized in that: Includes the following steps: (1) Apply dual-wavelength responsive photocurable ink to the printing area in an oxygen-containing atmosphere; (2) Project the second-band light onto the target location of the printing area to excite the photosensitizer to produce singlet oxygen. The singlet oxygen is consumed by the singlet oxygen quencher, causing a local hypoxia zone to form at the target location. (3) Projecting first-band light onto the target position to excite the photoinitiator to generate active free radicals. The free radical polymerization reaction is accelerated in a low-oxygen environment, which makes the ink solidify and form quickly.

3. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 2, characterized in that: Steps (2) and (3) can be executed sequentially or synchronously. When executed sequentially, the second band light is first projected for pre-oxygen consumption, and then the first band light is projected for curing. When executed synchronously, the second band light and the first band light are projected at the same time.

4. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 3, characterized in that: During sequential execution, the second-band light uses a planar projection pattern consistent with the current printed layer slice data to perform overall pre-oxygen consumption treatment on the target planar area.

5. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 2, characterized in that: When executed synchronously, the illumination area of ​​the second band of light is the same as or slightly smaller than the illumination area of ​​the first band of light.

6. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 2, characterized in that: The intensity and duration of the second-band light irradiation are configured to create an effective local hypoxia zone at the target location without causing thermal damage to the ink or non-specific side reactions.

7. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 2, characterized in that: The first and second bands of light are projected using either surface projection or volumetric projection.

8. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 7, characterized in that: When using volume projection, the first and second bands of light form a three-dimensional spatial light field, which simultaneously achieves oxygen consumption and curing in the three-dimensional region inside the ink body.

9. The photopolymerization 3D printing method with dual-wavelength accelerated curing according to claim 7, characterized in that: The oxygen-containing atmosphere is ambient air or an oxygen-containing gas environment with an oxygen inhibition effect.

10. A dual-wavelength accelerated curing photopolymerization printing device, used to implement the dual-wavelength accelerated curing photopolymerization 3D printing method according to claim 9, characterized in that, include: The system comprises an ink container, a first light source system, a second light source system, a spatial light modulation system, a motion platform, and a control unit. The control unit is electrically connected to the first light source system, the second light source system, the spatial light modulation system, and the motion platform, and is used to coordinate and control each component to execute the printing process. The spatial light modulation system is a digital light processing chip, a liquid crystal spatial light modulator, a digital micromirror array, or a three-dimensional light field holographic modulation module. The first light source system and the second light source system are independent light sources, which are combined by a beam-combining optical element and modulated by the same spatial light modulation unit, or modulated by independent spatial light modulation units respectively. The first light source system and the second light source system are switchable wavelength light sources that share the same spatial light modulation system, and the wavelength switching and projection timing are controlled by the control unit.

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