Multi-material high-precision photocuring 3D printing system based on dynamic micro-fluidic chip and manufacturing method

Abstract

The invention discloses a multi-material high-precision photocuring 3D printing system based on a dynamic micro-fluidic chip and a manufacturing method, and belongs to the technical field of additive manufacturing. Aiming at the technical bottleneck that in-layer multi-material composite distribution is difficult to realize by the existing photocuring technology, the invention creatively designs a printing system integrated with a fluid control chip, and the system sequentially comprises a three-dimensional motion system, the fluid control chip and a photocuring system from top to bottom. According to the fluid control chip, efficient switching and accurate patterned distribution of high-viscosity photosensitive resin are achieved through collaborative design of an array type material inlet / outlet and a micro-fluidic channel network in combination with piezoelectric micropump / pneumatic control and hydrophobic / hydrophilic modification of the inner wall of a flow channel. And the light curing system adopts a DLP / LCD technology to be matched with an ultraviolet light source to realize selective curing. Motion control, fluid driving and photocuring parameters are integrated through a closed-loop control system, and a multifunctional component with gradient hardness, conductivity or biocompatibility can be prepared. The limitation that traditional multi-material printing depends on resin pool switching is broken through, the printing efficiency and the material utilization rate are remarkably improved, and an innovative solution is provided for manufacturing of complex functional structures in the fields of bionic tissue, flexible electronics and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, and more particularly to a multi-material high-precision light-curing 3D printing system based on a dynamic microfluidic chip and a manufacturing method. BACKGROUND

[0002] Light-curing 3D printing technology, as an important branch of additive manufacturing, has been widely used in medical, aerospace, electronic devices and other fields due to its high precision, high surface quality and rapid prototyping capability. However, traditional light-curing technology mainly relies on the layer-by-layer curing of a single resin material, making it difficult to achieve the composite distribution of multiple materials within the same printing layer, which severely limits its application potential in the manufacturing of multifunctional complex structures. Currently, the mainstream method for multi-material light-curing printing is to introduce different materials by alternately replacing the resin tank, but this method has obvious efficiency bottlenecks: each material switching requires cleaning and refilling of the resin tank, resulting in a significant extension of the printing cycle, and cannot avoid cross-contamination caused by material residues. In addition, due to the lack of precise control over material distribution, traditional methods are difficult to achieve the patterning arrangement of multiple materials within the layer, making the printed parts unable to meet the needs of gradient performance or functional integration. For example, in the biomedical field, the printing of biomimetic tissues or organs often requires multiple materials to be distributed according to specific rules at the microscale to simulate the mechanical and biological properties of natural tissues; in the field of flexible electronics, precise alternating structures of conductive and insulating materials are crucial to device performance, and existing technologies are difficult to achieve such high-resolution multi-material composites.

[0003] In recent years, researchers have attempted to achieve multi-material distribution by improving inkjet printing and microfluidic technology, but these solutions still face challenges: inkjet printing is limited by material viscosity and printing speed, making it difficult to handle high-viscosity photosensitive resins; microfluidic technology can achieve microscale fluid control, but its structure is complex and lacks compatibility with existing light-curing systems (3). Therefore, developing a light-curing 3D printing technology that can efficiently and accurately control the distribution of multiple materials is key to breaking through the current technical bottlenecks. The present application achieves on-demand distribution and curing of multiple materials within and between layers by innovatively designing a fluid manipulation chip (2), combining the rheological properties of resins with dynamic control strategies, which not only significantly improves printing efficiency but also provides a new solution for the manufacturing of complex functional structures. This breakthrough in technology will promote the application of light-curing 3D printing in high-end fields such as biomimetic materials and intelligent devices, filling the gap in multi-material high-precision manufacturing in existing technologies. SUMMARY

[0004] The present application provides a multi-material high-precision light-curing 3D printing system based on a dynamic microfluidic chip and a manufacturing method, which realizes the high-precision composite distribution and stereoscopic manufacturing of two or more materials within and between layers through innovative design of the fluid manipulation chip structure and regulation of the rheological properties of resins.

[0005] A high-precision photopolymerization 3D printing system based on dynamic microfluidic chips for multiple materials includes: Three-dimensional motion system: used to drive the molding platform to move with high precision in the Z-axis direction. It adopts a high-precision linear motor, through precision guide rails and servo control to achieve a positioning accuracy of ±5μm in the Z-axis direction, and is equipped with a displacement sensor to monitor the position of the molding platform in real time. Fluid Manipulation Chip: Manufactured using multi-layer microfabrication technology, the fluid manipulation chip includes material inlets / outlets, a main channel, branch channels, and resin micropools. The resin micropools are located in the center of the fluid manipulation chip. The material inlets / outlets are arranged in a ring array, with 2-6 inlets / outlets. The material inlets / outlets are connected to the main channel, the branch channels are connected to the main channel, and the branch channels are connected to the resin micropools. The material inlets / outlets can be used alternately as material inlets or outlets. When used as inlets, each inlet is connected to an independent material supply system. The material supply system achieves precise delivery of photosensitive resin with a viscosity range of 50-5000 cP through a piezoelectric micropump or pneumatic control system, with a flow control accuracy of ±0.1 μL. The microfluidic channel network adopts a biomimetic fractal design, with a main channel width of 100-500μm and a branch channel width of 50-200μm. The inner wall of the channel is modified with an adjustable contact angle of 30°-120° through plasma treatment or chemical coating. Micro mixers and flow rate sensors are set at key nodes of the flow channel, with an accuracy of ±1%. The resin microcell is made of transparent quartz material with an adjustable capacity of 1-30mL. A temperature control module is set at the bottom with a temperature control accuracy of ±0.5℃. The waste recycling system is connected to the material inlet / outlet as the outlet. The waste recycling system realizes the clean recycling of uncured resin through a micro vacuum pump and a filter device, improving the material utilization rate by more than 30%. Photocuring system: Located below the resin microcell, it adopts DLP or LCD technology and is equipped with a high-power ultraviolet LED array with an adjustable wavelength of 365-405nm, a single LED power of 1-5W, and a total power of 20-100W. It achieves patterned exposure with a resolution of 10-50μm through a microlens array, and the exposure time is programmable controllable from 0.5-10s / layer. It also integrates an infrared temperature sensor to monitor the curing process in real time. Closed-loop control system: It adopts a multi-threaded real-time operating system and connects the motion controller, fluid controller and optical controller through a high-speed data bus. It achieves multi-parameter adaptive optimization based on PID algorithm and machine learning model. The closed-loop control system coordinates the control of the three-dimensional motion system, fluid manipulation chip and photopolymerization system through the motion controller, fluid controller and optical controller.

[0006] The piezoelectric micropump has a driving voltage of 50-200V and a response time of less than 10ms; the pneumatic control system has a pressure regulation range of 0-100kPa.

[0007] The micro mixer has a size of 200-500 μm; the filter has a pore size of 0.1-1 μm; and the micro vacuum pump has a negative pressure adjustment range of -5 to -20 kPa.

[0008] The high-speed data bus has a transmission rate of ≥1Gbps; the motion controller has a repeatability accuracy of ±2μm; the fluid controller has a pressure control accuracy of ±0.1kPa; and the optical controller has a light intensity control accuracy of ±1%.

[0009] A high-precision photopolymerization 3D printing manufacturing method based on dynamic microfluidic chips for multiple materials, using a high-precision photopolymerization 3D printing system based on dynamic microfluidic chips as described above, includes the following steps: Material formulation: 2-6 functionalized photosensitive resins are formulated according to application requirements. The matrix resin contains acrylate oligomers (40-70wt%), reactive diluents (20-50wt%), and photoinitiators (1-5wt%). Nanofillers (0-30wt%) can be added to achieve conductive, reinforcing, or bioactive functions. The resin viscosity is precisely controlled within the range of 50-5000 cP using a rheometer. Model processing: The 3D model is layered using specialized slicing software, with layer thickness adjustable from 10 to 100 μm, and a digital instruction set containing material distribution matrix, exposure parameters, and motion trajectory is generated. Printing process: The fluid manipulation chip precisely controls the opening timing, flow rate, and mixing ratio of each material inlet / outlet according to instructions, forming a multi-material patterned distribution with feature sizes of 50-500μm in the resin micropool. At the same time, the photocuring system synchronously triggers the ultraviolet exposure of the corresponding pattern. After each layer is cured, the forming platform is raised by one layer height along the Z-axis, and the doctor blade device ensures uniform layer thickness and flatness of ±1μm. The above process is repeated until the entire component is completed. Post-treatment: Perform a secondary curing at a strength of 10-50 mW / cm² for 5-30 minutes to ensure complete cross-linking of the material.

[0010] The opening interval for material inlet / outlet is 0.1-5s, and the flow rate is 0.5-10mL / min.

[0011] The beneficial effects of this invention are: Achieving high-precision patterned distribution and functional integration of multiple materials: This invention, through an innovative dynamic microfluidic chip design, enables the precise distribution of two or more materials within the same printing layer, overcoming the limitations of traditional photopolymerization technology that relies on a single material. The hydrophobic / hydrophilic modification of the microfluidic channel inner walls and precise flow rate control effectively suppress material cross-contamination, ensuring a clear interface. This technological breakthrough allows printed parts to possess properties such as gradient hardness, conductivity, or biocompatibility, meeting the stringent requirements for complex functional structures in fields such as biomimetic tissues and flexible electronics.

[0012] Significantly improved printing efficiency and material utilization: Compared to traditional resin tank switching methods (requiring frequent cleaning and refilling), the dynamic microfluidic chip of this invention, through array-type material inlet / outlet and piezoelectric micropump control, shortens the material switching time to 0.1-5 seconds, greatly reducing the printing cycle. Simultaneously, the negative pressure suction system in the waste tank can efficiently recover uncured resin, improving material utilization by over 30%. Combined with a high-resolution photopolymerization system and a 3D motion platform, it achieves synergistic optimization of high efficiency and high precision in multi-material printing.

[0013] Compatible with a wide viscosity range of materials, expanding application scenarios: Through optimized microfluidic channel design and pneumatic / piezoelectric actuation technology, the system supports stable delivery of high-viscosity photosensitive resins, overcoming the limitations of inkjet printing and other technologies on low-viscosity materials. Furthermore, by adjusting the resin composition, it can adapt to diverse material requirements, ranging from flexible elastomers to rigid structures, providing more possibilities for specialized applications such as medical implants and aerospace components. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the multi-material high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip according to the present invention; Figure 2 This is a schematic diagram of the structure of a dual-channel fluid manipulation chip; package Figure 3 This is a schematic diagram of a four-channel fluid manipulation chip. Figure 4 In specific embodiment 1 of the present invention, the dual-channel fluid manipulation chip can achieve patterned material distribution; Figure 5 This is a schematic diagram illustrating the effect of using a dual-channel fluid manipulation chip to create a three-dimensional sample in a specific embodiment 1 of the present invention.

[0015] Explanation of reference numerals in the attached figures 1. Three-dimensional motion system; 2. Fluid manipulation chip; 3. Photopolymerization system; 21. Material supply system; 22. Fluid manipulation chip; 23. Waste recycling system; 221. Material inlet / outlet; 222. Main channel; 223. Branch channel; 224. Resin micropool. Detailed Implementation

[0016] This invention provides a multi-material high-precision photopolymerization 3D printing system and manufacturing method based on a dynamic microfluidic chip. The specific embodiments of this invention are described in detail below with reference to the accompanying drawings, including a system structure description and two typical examples.

[0017] The multi-material high-precision photopolymerization 3D printing system based on dynamic microfluidic chip includes three main parts working together: three-dimensional motion system 1, fluid manipulation chip 2 and photopolymerization system 3. The three-dimensional motion system 1 adopts a high-precision linear motor driven molding platform, which achieves a positioning accuracy of ±5μm in the Z-axis direction through precision guide rails and servo control, and is equipped with a displacement sensor to monitor the platform position in real time. The fluid manipulation chip 2, as a core innovative component, is located in the middle of the system. It is manufactured using a multi-layer microfabrication process and includes 2-6 material inlets / outlets 221 (adjustable diameter 0.5-2mm) arranged in a ring array. Each inlet is connected to an independent material supply system 21. The precise delivery of photosensitive resin with a viscosity range of 50-5000cP is achieved through a piezoelectric micropump (driving voltage 50-200V, response time <10ms) or a pneumatic control system (air pressure adjustment range 0-100kPa). The microfluidic channel network adopts a biomimetic fractal design. The main channel 222 has a width of 100-500μm, and the branch channel 223 has a width of 50-200μm. The inner wall of the channel is modified with a contact angle of 30°-120° through plasma treatment or chemical coating. Micro mixers and flow rate sensors are set at key nodes of the flow channel. The resin microcell 224 is made of transparent quartz material with an adjustable capacity of 1-30 mL. A temperature control module (temperature control accuracy ±0.5℃) is provided at the bottom to maintain the optimal rheological properties of the resin. The distribution of multiple materials in the resin microcell 224 is synergistically regulated by the material supply sequence (interval 0.1-5s) and flow rate (0.5-10mL / min). Combined with the hydrophobic / hydrophilic modification of the inner wall of the flow channel, it can inhibit cross-mixing of materials and form a clear interface. The waste recycling system (23) realizes the clean recycling of uncured resin through a micro vacuum pump (negative pressure -5 to -20kPa adjustable) and a filter device (pore size 0.1-1μm), which improves the material utilization rate by more than 30%. The photocuring system 3 adopts DLP (Digital Light Processing) or LCD (Liquid Crystal Display) technology, and is equipped with a high-power ultraviolet LED array (wavelength adjustable from 365-405nm, single LED power 1-5W, total power 20-100W). It achieves patterned exposure with a resolution of 10-50μm through a microlens array, and the exposure time is programmable controllable from 0.5-10s / layer. It also integrates an infrared temperature sensor to monitor the curing process in real time. The entire system is coordinated by a closed-loop control system, employs a multi-threaded real-time operating system, and connects motion controllers, fluid controllers, and optical controllers via a high-speed data bus. It achieves multi-parameter adaptive optimization based on PID algorithms and machine learning models.

[0018] The multi-material high-precision photopolymerization 3D printing manufacturing method based on dynamic microfluidic chips includes the following steps: Material formulation: 2-6 functionalized photosensitive resins are formulated according to application requirements. The matrix resin contains acrylate oligomers (40-70wt%), reactive diluents (20-50wt%), and photoinitiators (1-5wt%). Nanofillers (0-30wt%) can be added to achieve functions such as conductivity, reinforcement, or bioactivity. The resin viscosity is precisely controlled within the range of 50-5000cP.

[0019] Model processing: The 3D model is processed into layers using specialized slicing software (layer thickness adjustable from 10-100μm) to generate a digital instruction set containing material distribution matrix, exposure parameters, and motion trajectory.

[0020] Printing process: The fluid manipulation chip 2 precisely controls the opening timing (interval 0.1-5s), flow rate (0.5-10mL / min), and mixing ratio of each material inlet / outlet 221 according to instructions, forming a multi-material patterned distribution with a feature size of 50-500μm in the resin micropool 224. At the same time, the photocuring system 3 synchronously triggers the ultraviolet exposure of the corresponding pattern (exposure time 0.5-10s / layer). After each layer is cured, the molding platform is raised by one layer height along the Z-axis. The above process is repeated until the entire component is completed.

[0021] Post-treatment: Perform a secondary curing at a strength of 10-50 mW / cm² for 5-30 minutes to ensure complete cross-linking of the material.

[0022] Manufacturing Method Example 1: Gradient Hardness Bionic Cartilage Manufacturing First, three functionalized photosensitive resins were prepared: Resin A was a flexible matrix (60wt% acrylate oligomer, viscosity 800cP), Resin B was a medium-hardness material (containing 20wt% nano-silica, viscosity 1500cP), and Resin C was a rigid reinforcing material (containing 30wt% hydroxyapatite, viscosity 3000cP). The bionic cartilage model was layered using slicing software (50μm layer thickness) to generate a material distribution matrix instruction. During printing, the fluid manipulation chip 2 controlled the sequential injection of the three materials according to the instruction (0.5s interval), with flow rates of 1.2mL / min, 0.8mL / min, and 0.5mL / min, respectively, forming a gradient distribution pattern within the resin microcell 224; simultaneous ultraviolet exposure was triggered (wavelength 385nm, power 30W, exposure time 3s / layer). After each layer cured, the platform increased by 50μm, and the process was repeated until completion. After a second curing process (strength 20mW / cm², time 15 minutes), the final component yields a biomimetic structure with gradient mechanical properties transitioning from cartilage to bone, with a compressive modulus gradient ranging from 0.5 to 3.0 GPa.

[0023] Manufacturing Method Example 2: Integrated Manufacturing of Flexible Electronic Devices. Conductive resin (containing 25wt% silver nanowires, viscosity 2000cP) and insulating resin (acrylate matrix, viscosity 500cP) were prepared. The flexible circuit model was layered (layer thickness 30μm), and the conductive and insulating regions were defined by a material distribution matrix. During printing, the fluid manipulation chip 2 alternately injected the two materials in a pulse mode (conductive resin flow rate 0.6mL / min, insulating resin flow rate 1.2mL / min, switching interval 0.2s), forming an alternating pattern with a linewidth of 50μm within the microcell; simultaneous curing was performed by UV exposure (wavelength 405nm, resolution 20μm, exposure time 2s / layer). The interlayer flatness (±1μm) was ensured using a scraper, with a total printing thickness of 300μm. After secondary curing (strength 15mW / cm², 10 minutes), a flexible circuit integrating conductive lines and insulating layers was obtained. The sheet resistance of the conductive lines was <0.1Ω / sq, the withstand voltage of the insulating layer was >1kV, and the bending radius reached 2mm. This embodiment demonstrates the advantages of the system in microscale multi-material integration, which is suitable for the integrated molding of wearable electronic devices.

Claims

1. A high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip, characterized in that, include: Three-dimensional motion system (1): used to drive the molding platform to move in the Z-axis direction with high precision. It adopts a high-precision linear motor and achieves a positioning accuracy of ±5μm in the Z-axis direction through precision guide rails and servo control. It is also equipped with a displacement sensor to monitor the position of the molding platform in real time. Fluid manipulation chip (2): Manufactured using multilayer micromachining technology, the fluid manipulation chip (2) includes a material inlet / outlet (221), a main channel (222), a branch channel (223), and a resin micropool (224). The resin micropool (224) is located in the middle of the fluid manipulation chip (2). The material inlet / outlet (221) is arranged in a ring array, with a quantity of 2-6. The material inlet / outlet (221) is connected to the main channel (222), the branch channel (223) is connected to the main channel (222), and the branch channel (223) is connected to the resin micropool (224). The material inlet / outlet (221) can be used alternately as a material inlet or outlet. When used as an inlet, each inlet is connected to an independent material supply system (21). The material supply system (21) achieves 50-5000 cP through a piezoelectric micropump or pneumatic control system. The photosensitive resin with a viscosity range is accurately delivered with a flow control accuracy of ±0.1μL / s. The microfluidic channel network adopts a biomimetic fractal design. The width of the main channel (222) is 100-500μm, and the width of the branch channel (223) is 50-200μm. The inner wall of the channel is modified with a contact angle of 30°-120° through plasma treatment or chemical coating. The key nodes of the flow channel are equipped with micro mixers and flow rate sensors with an accuracy of ±1%. The resin micro pool (224) is made of transparent quartz material with an adjustable capacity of 1-30mL. The bottom is equipped with a temperature control module with a temperature control accuracy of ±0.5℃. The waste recycling system (23) is connected to the material inlet / outlet (221) as the outlet. The waste recycling system (23) realizes the clean recycling of uncured resin through a micro vacuum pump and a filter device, and the material utilization rate is increased by more than 30%. Photocuring system (3): Set below the resin micropool (224), using DLP or LCD technology, equipped with a high-power ultraviolet LED array with an adjustable wavelength of 365-405nm, a single LED power of 1-5W, and a total power of 20-100W. It achieves patterned exposure with a resolution of 10-50μm through a microlens array, and the exposure time is programmable control of 0.5-10s / layer. It also integrates an infrared temperature sensor to monitor the curing process in real time. Closed-loop control system: It adopts a multi-threaded real-time operating system and connects the motion controller, fluid controller and optical controller through a high-speed data bus. It achieves multi-parameter adaptive optimization based on PID algorithm and machine learning model. The closed-loop control system coordinates the control of the three-dimensional motion system, fluid manipulation chip and photopolymerization system through the motion controller, fluid controller and optical controller.

2. The multi-material high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip according to claim 1, characterized in that, The piezoelectric micropump has a driving voltage of 50-200V and a response time of less than 10ms; the pneumatic control system has a pressure regulation range of 0-100kPa.

3. The multi-material high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip according to claim 1, characterized in that, The micro mixer has a size of 200-500 μm; the filter has a pore size of 0.1-1 μm; and the micro vacuum pump has a negative pressure adjustment range of -5 to -20 kPa.

4. The multi-material high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip according to claim 1, characterized in that, The transmission rate of the high-speed data bus is ≥1Gbps; the repeatability of the motion controller is ±2μm; the pressure control accuracy of the fluid controller is ±0.1kPa; and the light intensity control accuracy of the optical controller is ±1%.

5. A multi-material high-precision photopolymerization 3D printing manufacturing method based on a dynamic microfluidic chip, using a multi-material high-precision photopolymerization 3D printing system based on a dynamic microfluidic chip as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Material formulation: 2-6 functionalized photosensitive resins are formulated according to application requirements. The matrix resin contains acrylate oligomers (40-70wt%), reactive diluents (20-50wt%), and photoinitiators (1-5wt%). Nanofillers (0-30wt%) can be added to achieve conductive, reinforcing, or bioactive functions. The resin viscosity is precisely controlled within the range of 50-5000 cP using a rheometer. Model processing: The 3D model is layered using specialized slicing software, with layer thickness adjustable from 10 to 100 μm, and a digital instruction set containing material distribution matrix, exposure parameters, and motion trajectory is generated. Printing process: The fluid manipulation chip (2) precisely controls the opening timing, flow rate and mixing ratio of each material inlet / outlet (221) according to the instructions, forming a multi-material patterned distribution with a feature size of 50-500μm in the resin micropool (224). At the same time, the photocuring system (3) synchronously triggers the ultraviolet exposure of the corresponding pattern. After each layer is cured, the molding platform is raised by one layer height along the Z-axis. The scraper device ensures that the layer thickness is uniform and the flatness is ±1μm. The above process is repeated until the entire component is completed. Post-treatment: Perform a secondary curing at a strength of 10-50 mW / cm² for 5-30 minutes to ensure complete cross-linking of the material.

6. The manufacturing method according to claim 5, characterized in that, The opening interval of the material inlet / outlet (221) is 0.1-5s, and the flow rate is 0.5-10mL / min.

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