A multi-component real-time mixing coating type photo-curing printing system and method

Abstract

The application discloses a multi-component real-time mixing coating type photocuring printing system and method, and relates to the technical field of additive manufacturing and photocuring three-dimensional printing. The system comprises independent component containers, metering pumps, proportional control units, online mixers, short flow path discharge pipelines, coating film forming units, release film assemblies, surface exposure units, forming platforms and lifting mechanisms, excess material recycling temporary storage units and controllers. The method is executed in a layer cycle: after each component is metered and supplied, it is mixed online, transported to the coating film forming unit through a short flow path, and a thin layer is formed by the relative movement of the moving part and the release film assembly, peeled off after surface exposure and curing, and the unexposed excess material is recycled and preferentially reused in the subsequent layer. The application realizes the present preparation and use of multi-component materials, reduces the viscosity drift caused by dark reaction, reduces the peeling force through thin layer non-immersed curing, and improves the material utilization rate and the stability of the printing process.

Description

Technical Field

[0001] This invention relates to the fields of additive manufacturing and photopolymerization 3D printing technology, and in particular to a multi-component real-time mixing and coating photopolymerization printing system and method. Background Technology

[0002] In the current field of photopolymer 3D printing, the top-pull (bottom-up) surface exposure molding process is widely used. This type of process typically places the surface exposure device below the resin tank, where light passes through a transparent window at the bottom of the tank and a release film to expose and cure the photosensitive material layer by layer. The molding platform is located above the resin tank and moves periodically along the Z-axis, causing the cured layers to periodically separate from the release film, thus achieving layer-by-layer stacking. This process is relatively mature when using single-component, low-viscosity, and stable photosensitive resins. However, it usually exhibits significant limitations when the molding material is a multi-component system (especially a reactive system that requires pre-mixing) and / or a composite photopolymer material containing functional fillers.

[0003] On the one hand, multi-component materials often undergo continuous or dark reactions over time after mixing, causing time-related drift in material viscosity, rheological properties, and active component concentration. Existing pull-up processes typically require maintaining a certain liquid level in the resin tank to ensure material supply to the exposure area, inevitably leading to material retention within the tank. Insufficient circulation and renewal during printing further prolongs material residence time, resulting in gradually increasing viscosity, shortened usable time, and drift in the exposure and curing window. This ultimately leads to material scrap and waste, and reduces the stability and consistency of the printing process.

[0004] On the other hand, in the peeling stage, pull-up immersion molding not only needs to overcome the peeling force generated by the adhesion at the release interface, but also needs to overcome additional resistance such as viscous resistance and negative pressure adsorption generated by the immersion liquid, resulting in a large peak peeling force with significant fluctuations. When the material viscosity increases due to dark reaction or the rheology becomes more complex due to the presence of fillers, the above-mentioned resistance effects are further aggravated, which can easily lead to failures such as delamination, breakage, and deformation, reducing the molding success rate and limiting the printing speed. In addition, existing pull-up processes generally rely on the self-leveling and re-spreading of the material after peeling to form the next liquid layer. The self-leveling time is highly correlated with the material viscosity and thixotropy. When the viscosity of the mixture drifts or local gelation tends to occur, the self-leveling time increases significantly and is difficult to predict, resulting in prolonged interlayer cycle time and the risk of defects such as uneven thickness, air bubble entrainment, and surface streaks.

[0005] Furthermore, in traditional resin bath processes, the molded part needs to be repeatedly immersed in the resin in the bath during printing, and then peeled off from the release interface at the bottom of the bath. This immersion and peeling mechanism increases release resistance and peeling risk, and also causes the surface of the molded part to carry more uncured resin, resulting in cleaning burden and material loss. For two-component elastomers or multi-component reactive photocurable systems, existing technologies often require pre-mixing the two components in a certain proportion before printing, and then pouring them into the resin bath in one go or in excess to meet the continuous material supply requirements during printing. Since two-component systems may also undergo a certain degree of dark reaction under no-light conditions, the pre-mixed resin will exhibit viscosity drift, rheological changes, and uneven reaction over time in the resin bath.

[0006] Therefore, existing pull-up immersion exposure molding solutions have problems such as material retention leading to dark reaction accumulation and material waste, large and fluctuating peel load, and cycle time being strongly constrained by self-leveling when dealing with multi-component real-time mixed materials (especially two-component reactive resins). There is an urgent need for an improved photopolymer additive manufacturing system and method that can reduce material retention, achieve thin-layer non-immersion molding, and allow unexposed residues to be recycled and reused preferentially in subsequent layers. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-component real-time mixing and coating photocuring printing system and method to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides a multi-component real-time mixing coating photopolymerization printing system, comprising: Component A and Component B are used to store at least two flowable photocurable components, respectively. The metering pump includes a component A metering pump and a component B metering pump, which are respectively connected to the component A container and the component B container; A proportional control unit, connected to the metering pump, is used to set and adjust the flow ratio of each component and the total feed amount per layer; An online mixer, connected to the output of the metering pump, is used to mix the components in real time and output a mixed photocurable molding material; A short-flow discharge pipe is connected to the outlet of the online mixer; Release film assembly, including a light-transmitting release film and a support and tension structure for ensuring the flatness of the exposure window area; The coating and film forming unit is connected to the short flow path discharge pipe. The coating and film forming unit is a moving part, used to form relative movement with the release film assembly and quantitatively spread the mixed photocurable molding material on the surface of the release film to form a thin layer of predetermined thickness. A surface exposure unit is disposed on one side of the release film assembly and is used to perform surface exposure curing of the thin layer through the release film; The forming platform and lifting mechanism are located on the other side of the release film assembly and are used to support the cured layer and perform interlayer gap control and peeling actions; The waste material recycling / temporary storage unit is coupled to the coating film forming unit on the material path and is used to recycle unexposed waste material and reuse it preferentially in subsequent layer coating. The controller is connected to the proportional control unit, the metering pump, the online mixer, the coating and film forming unit, the surface exposure unit, the forming platform, and the lifting mechanism, respectively, and is used to coordinate the online mixing and feeding, coating and film forming, surface exposure and curing, peeling, and priority recycling of residual materials in a layer-by-layer cycle.

[0009] Preferably, the coating film-forming unit is a doctor blade coating head or a slot coating head.

[0010] Preferably, the short flow path discharge pipe is configured in conjunction with the controller so that the time from when the mixed photocurable molding material is mixed in the online mixer to when it is extruded and used for coating is less than 30 seconds.

[0011] Preferably, the waste material recycling / temporary storage unit is configured to recycle and temporarily store unexposed waste material by scraping backflow and / or suction recycling.

[0012] Preferably, the residual material recovery / temporary storage unit is equipped with a stirring device or a circulation device to keep the recovered residual material uniform and reduce sedimentation.

[0013] Preferably, the release film assembly is a roll-to-roll release film mechanism, including an unwind roller, a traction roller and a take-up roller, and is equipped with a tension control component to maintain the flatness and positional stability of the release film in the coating and exposure areas.

[0014] Preferably, the online mixer is a static mixer or a dynamic mixer, and adopts a modular quick-change structure.

[0015] Preferably, the controller calculates the amount of material supplied per layer based on the target layer thickness, target spreading area, and amount of reusable residual material to avoid overmixing; and when a printing pause, fault, or interlayer wait exceeds a threshold is detected, the material supply and mixing are stopped, and the unexposed material in the mixing or coating section is recycled to the residual material recycling / temporary storage unit and / or replaced via the bypass discharge / rinsing interface.

[0016] Preferably, the metering pump is at least one of a peristaltic pump, a syringe pump, a gear pump, or a plunger pump.

[0017] This invention also provides a multi-component real-time mixing and coating photocuring printing method, comprising the following layer-by-layer cyclic steps: At least two flowable photocurable components are stored independently in component A container and component B container, respectively; The controller controls the components to be delivered to the online mixer in real time via metering pumps according to the set ratio, so as to obtain a mixed photocurable molding material; The mixed photocurable molding material is transported to the coating and film forming unit through a short flow path discharge pipe. The coating and film forming unit acts as a moving part and forms relative movement with the release film assembly, quantitatively spreading the mixed photocurable molding material on the surface of the release film to form a thin layer of predetermined thickness. The thin layer is surface-exposed and cured through the release film by the surface exposure unit to form a single-layer structure and bond it with the already formed layer; The forming platform and lifting mechanism perform lifting and peeling actions to separate the interface between the cured layer and the release film and adjust it to the next layer forming gap; Unexposed residue is recycled to the residue recycling / temporary storage unit and reused preferentially during subsequent layer coating. Any shortfall is supplemented by mixed photocurable molding material output from the online mixer. The method reduces liquid resistance during the peeling stage through thin-layer non-immersion curing and peeling, and reduces the dark reaction effect caused by the retention of mixed materials through online mixing and short-path delivery.

[0018] Compared with the prior art, the present invention has the following advantages and technical effects: The multi-component real-time mixing and coating photopolymerization printing system and method provided by this invention achieves on-demand preparation and significantly reduces the amount and residence time of mixed materials in the system through independent storage and online real-time mixing of components. Preferably, the time from mixing to extrusion and use is less than 30 seconds, thereby mitigating viscosity drift and process window drift caused by dark reactions and reducing material scrap. Layer thickness is determined by metering coating using a coating film-forming unit (dosage coater or slot coater), reducing reliance on material self-leveling, making interlayer cycle time more controllable, and reducing the risk of defects such as uneven thickness, air bubbles, and surface streaks. Thin-layer non-immersion curing and peeling at the release film interface reduces liquid resistance, thereby reducing peel peak force and its fluctuations and reducing the risk of failure such as delamination and breakage. The recovery of unexposed residue and its priority reuse in subsequent layers improves material utilization and reduces material changeover and maintenance costs. Furthermore, the use of a quick-change static / dynamic mixer module allows for rapid switching between different material systems, reducing clogging, cleaning, and maintenance costs, and improving production continuity and process applicability. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0020] Figure 1 This is a block diagram of the overall structure of the multi-component real-time mixing coating photocuring printing system of the present invention.

[0021] Figure 2 This is a schematic diagram of the single-layer printing timing of the present invention.

[0022] Figure 3 This is a schematic diagram of the reflux storage of the present invention.

[0023] Figure 4 This is a schematic diagram of the overall system structure of the present invention when using a peristaltic pump + static mixer + slot coating head + closed-loop roll + DLP.

[0024] Figure 5 This is a schematic diagram of the overall system structure of the present invention when using an injection pump + dynamic mixer + doctor blade coating head + winding + LCD.

[0025] In the diagram: 1. Component A container; 2. Component B container; 3. Component A metering pump; 4. Component B metering pump; 5. Proportioning control unit; 6. Online mixer; 7. Short flow path discharge pipeline; 8. Coating and film forming unit; 9. Release film assembly; 10. Surface exposure unit; 11. Forming platform; 12. Lifting mechanism; 13. Residual material recovery / temporary storage unit. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] like Figures 1 to 5As shown, this invention provides a multi-component real-time mixing and coating photocuring printing system, including a component A container 1 and a component B container 2, a component A metering pump 3 and a component B metering pump 4, a proportioning control unit 5, an online mixer 6, a short-flow-path discharge pipeline 7, a coating and film-forming unit 8, a release film assembly 9, a surface exposure unit 10, a forming platform 11 and a lifting mechanism 12, a residual material recovery / temporary storage unit 13, and a controller. Component A container 1 and component B container 2 are used to store at least two flowable photocurable components. Component A container 1 is connected to the supply pipeline via component A metering pump 3, and component B container 2 is connected to the supply pipeline via component B metering pump 4. Component A metering pump 3 and component B metering pump 4 can be peristaltic pumps, injection pumps, gear pumps, plunger pumps, or other controllable flow pumps, or they can be pump-valve combinations with mass / volume metering functions. The proportional control unit 5 is signal-connected to the component A metering pump 3 and the component B metering pump 4, and is used to set and adjust the flow ratio of each component and the total feed amount per layer. The proportional control unit 5 can realize open-loop control or closed-loop control. In closed-loop control, it can combine feedback information such as flow rate, pressure, and pump motor load for proportion correction and anomaly detection. The online mixer 6 is connected to the output of the component A metering pump 3 and the component B metering pump 4, and is used to mix the components in real time and output the mixed photocurable molding material. The online mixer 6 can be a static mixer or a dynamic mixer, and can be optionally configured with temperature control, pressure monitoring, and bypass discharge / rinsing interface. The outlet of the online mixer 6 is connected to the material of the coating film forming unit 8 through the short flow path discharge pipe 7, which is used to shorten the time from mixing completion to coating use. The coating film forming unit 8 is located above or adjacent to the release film assembly 9, and is used to quantitatively spread the mixed molding material on the surface of the release film to form a thin layer of predetermined thickness. The release film assembly 9 includes a light-transmitting release film and a support and tension structure to ensure the flatness of the exposure window area. The coating and film-forming unit 8 is a moving component that reciprocates or moves unidirectionally in a predetermined direction under the control of a controller, forming relative motion with the release film assembly 9 to complete the thin layer spreading. The thin layer thickness is determined by parameters such as the material feed rate, the coating gap / geometric parameters of the coating and film-forming unit 8, and the movement speed of the coating and film-forming unit 8, thereby reducing reliance on natural material leveling. The surface exposure unit 10 is located on the other side of the release film assembly 9, preferably below the release film, for surface exposure and curing of the thin layer through the release film; the surface exposure unit 10 can employ projection / area array exposure schemes such as DLP or LCD. The forming platform 11 and lifting mechanism 12 are located above the release film, for carrying the cured layer and performing interlayer gap control and peeling actions. The waste material recovery / temporary storage unit 13 is coupled to the coating and film-forming unit 8 on the material path, for recovering unexposed waste material and prioritizing its reuse in subsequent layer coatings. Unexposed residual materials can be scraped back into the residual material recycling / temporary storage unit 13, or they can be sucked back into the residual material recycling / temporary storage unit 13, or a combination of both methods can be used.When the next coating layer begins, the controller prioritizes the unexposed residual material in the residual material recovery / temporary storage unit 13 for spreading. Any shortfall is supplemented by new mixed material output from the online mixer 6, thereby improving material utilization and reducing waste generation. The controller is electrically or signal-connected to the proportional control unit 5, component A metering pump 3, component B metering pump 4, online mixer 6, coating and film forming unit 8, surface exposure unit 10, forming platform 11, and lifting mechanism 12. It performs time-series linkage control on a layer-by-layer basis for feeding, proportioning, mixing, coating and film forming, exposure and curing, peeling and lifting, and priority reuse of residual material. In case of pause / abnormal operating conditions, it executes control strategies such as stopping feeding and mixing, and recovering or replacing materials in the mixing section to reduce the risk of blockage and performance drift caused by the dark reaction.

[0028] Through the above system structure, online real-time mixing of multi-component photocurable materials, quantitative coating and film formation, thin-layer exposure and curing of release film interfaces, and recycling and priority reuse of unexposed residual materials can be realized, thereby significantly reducing the impact of dark reactions caused by the retention of mixed materials and improving the stability of the printing process and the utilization rate of materials.

[0029] The scheme was further optimized so that coating film forming unit 8 is a doctor blade coating head or a slot coating head.

[0030] The blade coating head controls the layer thickness through the gap between the blade and the release film, while the slot coating head adjusts the gap between the slot lip and the release film using a gap adjustment mechanism to form a thin material layer with controllable and uniform thickness. When the coating unit 8 is a blade coating head, it moves along a predetermined path as a moving part, forming relative motion with the release film assembly 9, quantitatively spreading the mixed photocurable molding material onto the surface of the release film to form a thin layer. When the coating unit 8 is a slot coating head, the mixed material enters the slot coating head, and the gap between its lip and the release film is adjusted by the gap adjustment mechanism to stabilize the coating thickness within the range of 25 micrometers to 250 micrometers. By using either a blade coating head or a slot coating head in the coating unit 8, different material systems and process requirements can be flexibly adapted. The blade coating head is suitable for higher viscosity materials, while the slot coating head is suitable for lower viscosity materials and can provide higher coating accuracy and uniformity.

[0031] The scheme was further optimized by setting the short flow path discharge pipe 7 in conjunction with the controller, so that the time from mixing the photocurable molding material in the online mixer 6 to extrusion and coating is less than 30 seconds.

[0032] The controller ensures that the mixed material reaches the coating unit 8 from the online mixer 6 and participates in coating in the shortest possible time by controlling the length and inner diameter of the short-flow outlet pipe 7 and the delivery speed of component A metering pump 3 and component B metering pump 4. By controlling the time from the completion of mixing to participation in coating within 30 seconds, the viscosity drift and process window drift caused by the dark reaction after mixing of multi-component materials can be significantly reduced, ensuring that the material completes curing and forming within the optimal process window.

[0033] The scheme is further optimized so that the waste material recycling / temporary storage unit 13 is configured to recycle and temporarily store the unexposed waste material by scraping backflow and / or suction recycling.

[0034] The scraping-back method is suitable for coating unit 8 with a doctor blade coating head. The doctor blade scrapes away any unexposed material after coating and guides it back to the waste material recovery / temporary storage unit 13. The suction recovery method is suitable for coating unit 8 with a slot coating head or doctor blade coating head. A recovery pump draws the unexposed waste material back to the waste material recovery / temporary storage unit 13. Both methods can be used individually or in combination to improve the efficiency and reliability of waste material recovery. By recovering and temporarily storing unexposed waste material through scraping-back and / or suction recovery, efficient recovery of unexposed waste material can be achieved, reducing material waste and providing material assurance for priority reuse in subsequent layers.

[0035] To further optimize the solution, the residual material recovery / temporary storage unit 13 is equipped with a stirring device or a circulation device to keep the recovered residual material uniform and reduce sedimentation.

[0036] The stirring device can be a mechanical impeller or a magnetic stirrer, and the circulation device can be a circulation pump to pump the material from the bottom of the waste material recovery / temporary storage unit 13 to the top for circulation. The waste material recovery / temporary storage unit 13 can also be equipped with a liquid level sensor to monitor the recovery amount and a temperature sensor to monitor the material temperature. By setting up a stirring device or a circulation device in the waste material recovery / temporary storage unit 13, the compositional uniformity of the recovered waste material can be maintained, avoiding uneven material properties caused by sedimentation or localized reactions, and ensuring the quality stability of the recycled material.

[0037] Further optimization of the scheme: the release film assembly 9 is a roll-to-roll release film mechanism, including an unwinding roller, a traction roller and a take-up roller, and is equipped with a tension control component to maintain the flatness and positional stability of the release film in the coating and exposure areas.

[0038] The release film is driven by a winding mechanism, which operates continuously or intermittently. The winding mechanism uses tension control to ensure a smooth and stable film surface, guaranteeing coating uniformity and exposure alignment accuracy. The release film can be a fixed or renewable structure, and can be made from thin film substrates with release properties, such as PET film. By employing a winding release film mechanism and incorporating tension control components, the flatness and positional stability of the release film in the coating and exposure areas can be ensured, thereby improving the uniformity of the coating thickness and the alignment accuracy during exposure and curing.

[0039] Further optimization of the scheme: the online mixer 6 is either a static mixer or a dynamic mixer, and adopts a modular quick-change structure.

[0040] The static mixer incorporates a helical mixing element to achieve flow separation, recombination, and shearing during the flow process, ensuring thorough mixing of components. The dynamic mixer features a motor-driven rotor or miniature screw to provide stronger shear mixing capabilities, suitable for material systems with high viscosity or high mixing difficulty. A modular quick-change structure connects to upstream and downstream pipelines via self-sealing quick-connect fittings, allowing for the replacement of the static mixing core and dynamic mixer module without altering the overall system structure. The modular quick-change structure of the online mixer 6 enables rapid switching between different material systems, reducing clogging, cleaning, and maintenance costs, and improving production continuity and process applicability.

[0041] The scheme is further optimized by the controller calculating the amount of material to be supplied for each layer based on the target layer thickness, target spreading area and amount of reusable residual material to avoid overmixing; and when a printing pause, fault or interlayer wait exceeds the threshold is detected, the material supply and mixing are stopped, and the unexposed material in the mixing section or coating section is recycled to the residual material recycling / temporary storage unit 13 and / or replaced through the bypass discharge / rinsing interface.

[0042] The controller can also judge changes in material state based on signals such as pressure, flow rate, or motor load, and accordingly perform pump speed compensation, alarms, or trigger maintenance actions to improve long-term operational consistency. Through the controller's on-demand feeding strategy and pause protection strategy, material retention and waste caused by over-mixing can be avoided, and feeding and mixing can be stopped promptly under abnormal operating conditions to recover or replace unexposed materials, thereby reducing the risks of blockage and performance drift caused by dark reactions.

[0043] Further optimization of the scheme involves using a metering pump that is at least one of a peristaltic pump, a syringe pump, a gear pump, or a plunger pump.

[0044] Peristaltic pumps offer advantages such as easy maintenance and reduced risk of cross-contamination; syringe pumps provide high metering accuracy; gear pumps and plunger pumps are suitable for conveying high-pressure, high-viscosity materials. Depending on the material system and process requirements, component A metering pump 3 and component B metering pump 4 can be of the same or different types in combination, for example, combining one syringe pump with one peristaltic pump to achieve a balance between accuracy and continuous feeding capacity. By employing various types of pumps and their combinations for component A metering pump 3 and component B metering pump 4, different material systems and accuracy requirements can be flexibly adapted to, improving the system's versatility and reliability while ensuring metering accuracy.

[0045] This invention also provides a multi-component real-time mixing and coating photocuring printing method, comprising the following layer-by-layer cyclic steps: At the beginning of the layer cycle, the controller calculates the total amount of material required for the layer and the amount of new mixed material to be added based on the target layer thickness, target spreading area, and available residual material in the residual material recovery / temporary storage unit 13. It then controls the proportional control unit 5 to issue mixing ratio and flow rate commands to the component A metering pump 3 and the component B metering pump 4, ensuring that component A and component B are metered and output through their respective independent channels. Subsequently, each component enters the online mixer 6 for real-time mixing to form a mixed photocurable molding material. The mixed material is then transported to the coating film forming unit 8 via the short flow path discharge pipe 7. The controller ensures that the time from the completion of mixing to extrusion and application of the mixed material is less than 30 seconds.

[0046] During the coating and film-forming stage, the coating and film-forming unit 8 moves along a predetermined path as a moving component, forming relative motion with the release film assembly 9. It coordinates the available residual material in the residual material recovery / temporary storage unit 13 with the new mixture output from the online mixer 6 according to the controller's scheduling to participate in the spreading process, forming a thin material layer that meets the set layer thickness. Subsequently, the surface exposure unit 10 performs surface exposure curing on the thin layer based on the slice image, causing the corresponding area to solidify and bond with the already formed layer to form the current layer structure.

[0047] During the peeling and interlayer adjustment stage, the forming platform 11 and the lifting mechanism 12 perform lifting and peeling actions to separate the cured layer from the release film interface and adjust it to the next layer forming gap. Since the method adopts a non-immersion forming of a thin layer at the release film interface, it can reduce the liquid viscosity resistance and negative pressure adsorption effect during the peeling stage compared with an immersion resin tank, thereby helping to reduce the peeling peak force and its fluctuation and improve the forming stability.

[0048] During the waste material recovery and priority reuse stage, the controller drives the waste material recovery / temporary storage unit 13 to recover and temporarily store the unexposed waste material, so that it can be prioritized for use at the beginning of the next coating layer; when the waste material is insufficient, it is supplemented by new mixed material output by the online mixer 6. The above steps are repeated layer by layer until printing is completed.

[0049] Through the above methods and steps, the synergistic process of "online metering mixing - quantitative coating and film formation - exposure and curing of release film thin layer - recycling of residual material and priority reuse in subsequent layers" of multi-component photocurable materials can be achieved. This allows the mixture to be prepared and used immediately, reducing retention and dark reaction accumulation. Thin-layer non-immersion curing and peeling are used to reduce peel load, and the layer thickness is determined by coating metering to reduce dependence on self-leveling, thereby improving material utilization and process stability.

[0050] The multi-component real-time mixing and coating photocuring printing system and method provided by this invention achieves on-demand preparation and significantly reduces the amount and residence time of mixed materials in the system through independent storage and online real-time mixing of components. Preferably, the time from mixing to extrusion and use is less than 30 seconds, thereby mitigating viscosity drift and process window drift caused by dark reactions and reducing material waste. The coating thickness is determined by metering coating using the coating film forming unit 8 (dosage coater or slot coater), reducing reliance on material self-leveling, making interlayer cycle time more controllable, and reducing the risk of defects such as uneven thickness, air bubbles, and surface streaks. The non-immersion curing and peeling of the release film interface thin layer reduces liquid resistance, thereby reducing the peak peeling force and its fluctuations, and reducing the risk of failure such as delamination and breakage. By recycling unexposed residue and prioritizing its reuse in subsequent layers, material utilization is improved and material replacement and maintenance costs are reduced. In addition, the use of quick-change static / dynamic mixer modules allows the system to switch quickly between different material systems, reducing clogging, cleaning and maintenance costs, and improving production continuity and process applicability.

[0051] Example 1: Two-component fixed ratio, static mixer, doctor blade coating head, scraping and reflux temporary storage and priority reuse.

[0052] Component A container 1 and component B container 2 are sealed to store components A and B respectively. Component A metering pump 3 and component B metering pump 4 output each component according to a fixed ratio under the control of the controller and proportional control unit 5. Each component enters the static online mixer 6 for mixing. The mixed material is then transported to the coating and film-forming unit 8 (in this embodiment, a doctor blade coating head) via the short flow path discharge pipe 7. The controller ensures that the time from the completion of mixing to extrusion and coating is preferably less than 30 seconds. The coating and film-forming unit 8, as a moving part, performs doctor blade coating on the surface of the release film assembly 9 to form a set layer thickness. The surface exposure unit 10 exposes and cures the thin layer through the release film. After exposure, the forming platform 11 and lifting mechanism 12 perform peeling and interlayer gap adjustment. Unexposed residual material is scraped back into the residual material recycling / temporary storage unit 13 and temporarily stored. When the next coating layer begins, the controller prioritizes the residual material in the residual material recycling / temporary storage unit 13 to participate in the spreading. The insufficient part is supplemented by the online mixer 6, thereby improving the material utilization rate and reducing material retention and scrap.

[0053] Example 2: Two-component fixed ratio, dynamic mixer, slot coating head, suction recovery and temporary storage with priority reuse.

[0054] In this embodiment, the online mixer 6 is a dynamic online mixer, and can be optionally equipped with temperature control to stabilize viscosity. The coating film forming unit 8 is a slot coating head. The mixed material is conveyed to the slot coating head through the short flow path discharge pipe 7. The slot coating head adjusts the gap between its lip and the release film through a gap adjustment mechanism to stabilize the coating thickness within the range of 25 micrometers to 250 micrometers. The controller also preferably ensures that the time from the completion of mixing to the extrusion and use of the mixed material is less than 30 seconds. Unexposed residue is collected by suction at the end of coating or in the recycling area and temporarily stored in the residue recycling / temporary storage unit 13. When coating the next layer, the controller prioritizes reusing the residue and replenishing with new mixed material. Other steps are the same as in Embodiment 1.

[0055] Example 3: Implementation of a combination of roll-to-roll release film and slot coating head In this embodiment, the release film assembly 9 is a roll-to-roll release film mechanism, including an unwind roller, a traction roller, and a take-up roller, and is equipped with a tension control component to maintain the flatness and positional stability of the release film in the coating and exposure areas. The mixed material enters the slit coating head, which adjusts the gap between its lip and the release film through a gap adjustment mechanism to stabilize the coating thickness within the range of 25 micrometers to 250 micrometers. The release film is driven by the roll-to-roll mechanism to move continuously or intermittently. The roll-to-roll mechanism uses tension control to keep the film surface flat and stable, ensuring coating uniformity and exposure alignment accuracy. When the thin layer of material carried by the release film reaches the exposure position, the surface exposure unit 10 performs surface exposure curing on the thin layer according to the slice data. Unexposed residual material is temporarily stored in the residual material recovery / temporary storage unit 13 by suction recovery; during the next coating layer, the controller prioritizes reusing the residual material and replenishes the new mixture. Since the roll-to-roll release film mechanism can achieve continuous or intermittent renewal of the release film, it helps to maintain the cleanliness of the release film surface and the consistency of release performance, further improving the stability of the printing process.

[0056] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-component real-time mixing and coating photocuring printing system, characterized in that, include: Component A container (1) and component B container (2) are used to store at least two flowable photocurable components respectively; The metering pump includes a component A metering pump (3) and a component B metering pump (4), and is connected to the component A container (1) and the component B container (2) respectively. The proportional control unit (5) is connected to the metering pump and is used to set and adjust the flow ratio of each component and the total feed amount of each layer. An online mixer (6) is connected to the output of the metering pump and is used to mix the components in real time and output the mixed photocurable molding material. The short-flow discharge pipe (7) is connected to the outlet of the online mixer (6); Release film assembly (9) includes a light-transmitting release film and a support and tension structure for ensuring the flatness of the exposure window area; The coating film forming unit (8) is connected to the short flow path discharge pipe (7). The coating film forming unit (8) is a moving part, used to form relative movement with the release film assembly (9) and quantitatively spread the mixed photocurable molding material on the surface of the release film to form a thin layer of predetermined thickness. A surface exposure unit (10) is disposed on one side of the release film assembly (9) and is used to perform surface exposure curing of the thin layer through the release film; The forming platform (11) and lifting mechanism (12) are located on the other side of the release film assembly (9) and are used to carry the cured layer and perform interlayer gap control and peeling action; The waste material recycling / temporary storage unit (13) is coupled to the coating film forming unit (8) on the material path and is used to recycle unexposed waste material and reuse it preferentially in subsequent layer coating. The controller is connected to the proportional control unit (5), the metering pump, the online mixer (6), the coating and film forming unit (8), the surface exposure unit (10), the forming platform (11), and the lifting mechanism (12) respectively, and is used to coordinate the online mixing and feeding, coating and film forming, surface exposure and curing, peeling, and priority recycling of residual materials in a layer-by-layer cycle.

2. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The coating film forming unit (8) is a doctor blade coating head or a slot coating head.

3. The multi-component real-time mixing coating photocuring printing system according to claim 1, characterized in that, The short flow path discharge pipe (7) is configured in conjunction with the controller so that the time from mixing the photocurable molding material in the online mixer (6) to extrusion and coating is less than 30 seconds.

4. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The residual material recycling / temporary storage unit (13) is configured to recycle and temporarily store unexposed residual materials by scraping backflow and / or suction recycling.

5. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The residual material recovery / temporary storage unit (13) is equipped with a stirring device or a circulation device to keep the recovered residual material uniform and reduce sedimentation.

6. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The release film assembly (9) is a roll-up release film mechanism, including an unwinding roller, a traction roller and a take-up roller, and is equipped with a tension control assembly to maintain the flatness and positional stability of the release film in the coating and exposure areas.

7. The multi-component real-time mixing coating photocuring printing system according to claim 1, characterized in that, The online mixer (6) is either a static mixer or a dynamic mixer, and it adopts a modular quick-change structure.

8. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The controller calculates the amount of material supplied for each layer based on the target layer thickness, target spread area and amount of reusable residual material to avoid overmixing; and when a printing pause, fault or interlayer wait exceeds the threshold is detected, the material supply and mixing are stopped, and the unexposed material in the mixing section or coating section is recycled to the residual material recycling / temporary storage unit (13) and / or replaced via the bypass discharge / rinsing interface.

9. The multi-component real-time mixing coating photopolymerization printing system according to claim 1, characterized in that, The metering pump is at least one of a peristaltic pump, a syringe pump, a gear pump, or a plunger pump.

10. A multi-component real-time mixing and coating photocuring printing method, characterized in that, This includes the following steps, executed in a layer-by-layer loop: At least two flowable photocurable components are stored independently in component A container (1) and component B container (2); The controller controls the components to be delivered to the online mixer (6) in real time via metering pumps according to the set ratio to obtain a mixed photocurable molding material; The mixed photocurable molding material is transported to the coating film forming unit (8) through the short flow path discharge pipe (7). The coating film forming unit (8) acts as a moving part and forms relative movement with the release film assembly (9) to quantitatively spread the mixed photocurable molding material on the surface of the release film to form a thin layer of predetermined thickness. The thin layer is surface exposed and cured through the release film by the surface exposure unit (10) to form a single-layer structure and bond it with the formed layer; The forming platform (11) and the lifting mechanism (12) perform lifting and peeling actions to separate the interface between the cured layer and the release film and adjust it to the next layer forming gap; Unexposed material is recycled to the material recycling / temporary storage unit (13) and reused first during subsequent layer coating. Any shortfall is supplemented by the mixed photocurable molding material output by the online mixer (6). The method reduces liquid resistance during the peeling stage through thin-layer non-immersion curing and peeling, and reduces the dark reaction effect caused by the retention of mixed materials through online mixing and short-path delivery.

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