Post-processing method, system, device and readable medium for photocured 3D printed products

Abstract

The application discloses a light-cured 3D printing product post-processing method, system, device and readable medium; the post-processing method comprises the following steps: loading matched post-processing prescription parameters, introducing inert gas into a post-processing cavity and preheating, obtaining the reflection intensity of each representative workpiece in multiple monitoring wave bands, calculating batch consistency index and comprehensive curing state index, performing closed-loop dynamic adjustment to end the post-processing, etc.; the system comprises a control module and an environment acquisition module, a multi-waveband monitoring module, a curing light source module, an inert gas conveying module and a ventilation module which are in communication connection with the control module. Through the post-processing method and the post-processing system, the curing efficiency and quality are improved, the environment state and the workpiece curing characterization quantity are monitored, and closed-loop regulation and control are realized based on the quantifiable curing state index, so that the consistency, repeatability and material adaptability of the post-processing are improved.

Description

Technical Field

[0001] This invention relates to the field of 3D printing post-processing technology, and more specifically to post-processing methods, systems, equipment, and readable media for photopolymer 3D printed products. Background Technology

[0002] The statements in this section are merely background information related to this application and do not necessarily constitute prior art.

[0003] Printed parts produced by photopolymer 3D printing (such as DLP, LCD, SLA, etc.) usually require post-processing curing after printing to further improve the degree of cross-linking, mechanical properties, wear resistance and dimensional stability, and reduce residual monomers and surface stickiness.

[0004] Existing technologies typically involve nitrogen purging and light exposure of the printed parts for a preset duration, without online characterization of the actual cured state of the printed parts. While existing technologies offer the advantage of simplicity, their lack of online characterization of the actual cured state makes them difficult to adapt to variations in materials, colors, thicknesses, and loading quantities. Specifically, existing technologies also suffer from at least the following drawbacks:

[0005] 1. Oxygen inhibition leads to insufficient surface curing: Oxygen inhibits free radical polymerization, which can cause problems such as stickiness, insufficient curing, and poor wear resistance in the surface layer; and it is difficult to ensure that the oxygen concentration remains below the critical threshold by simply using a fixed ventilation time.

[0006] 2. Poor curing consistency of different printed parts / different loading conditions: Differences in material type, color, thickness, filler, structural complexity, loading quantity, etc. will cause differences in light dose distribution and thermal history, making it difficult to adapt fixed process parameters, resulting in both under-curing and over-curing.

[0007] 3. Lack of online observable measurement of the actual curing process of the workpiece: Monitoring only the cavity temperature cannot reflect the degree of curing on the surface / local area of ​​the workpiece, making it difficult to reliably determine the curing endpoint.

[0008] 4. Lack of quantifiable termination criteria: Most equipment ends at a fixed time, which cannot guarantee that the target curing state will be achieved, resulting in insufficient batch stability.

[0009] In view of this, how to solve the problems in the existing technology, such as the reliance on fixed time for post-processing, the inability to accurately characterize the actual curing process of the workpiece, the unreliability of the termination criteria, and the insufficient curing uniformity under complex loading conditions, which lead to the inability to meet the post-processing requirements of high precision and high consistency for batch workpieces, has become the subject of this invention. Summary of the Invention

[0010] The purpose of this invention is to provide a post-processing method, system, device, and readable medium for photopolymer 3D printed products.

[0011] To achieve the above objectives, the first aspect of this invention adopts the following technical solution: a post-processing method for photopolymer 3D printed products, the post-processing method comprising:

[0012] Obtain the workpiece information of the workpiece to be post-processed, and load the matching post-processing prescription parameters;

[0013] Inert gas is introduced into the post-processing chamber and preheated. The oxygen concentration and temperature in the post-processing chamber are collected in real time. When the oxygen concentration is continuously lower than the target oxygen concentration threshold and the low oxygen confirmation time is reached, the irradiation stage is entered.

[0014] Surface reflection samples were taken from representative workpieces selected in the same batch across multiple monitoring bands to obtain the reflection intensity of each representative workpiece across multiple monitoring bands.

[0015] The surface curing index of a single piece is calculated based on the dual-band reflection intensity, and then the batch consistency index and the comprehensive curing state index are calculated by combining the surface curing index of the single piece.

[0016] Based on the value and trend of the comprehensive curing state index, a closed-loop dynamic adjustment is made, at least one or more of the following parameters: illumination parameters, inert gas flow rate, or fan parameters.

[0017] When the overall curing state index continues to meet the standard and the oxygen concentration and chamber temperature always meet the constraints, the final treatment is completed.

[0018] The second aspect of the present invention is to propose a 3D printed product post-processing system, the system comprising a control module and an environment acquisition module, a multi-band monitoring module, a curing light source module, an inert gas delivery module, and a ventilation module that are communicatively connected to the control module;

[0019] The control module is used to execute a control program stored in a computer-readable medium to implement the photopolymerization 3D printing product post-processing method described in Embodiment 1;

[0020] The environmental acquisition module is used to collect the oxygen concentration and temperature inside the post-processing chamber in real time and transmit them to the control module.

[0021] The multi-band monitoring module is used to sample the surface reflection of representative workpieces selected in the same batch across multiple monitoring bands, and to obtain the reflection intensity of each representative workpiece in multiple monitoring bands.

[0022] The curing light source module is used to irradiate with different light intensities according to the instructions of the control module;

[0023] The inert gas delivery module is used to deliver inert gas at different flow rates according to the instructions of the control module.

[0024] The ventilation module is used to perform ventilation circulation at different flow rates according to the instructions of the control module.

[0025] The third aspect of the present invention adopts the following technical solution: a photopolymer 3D printing product post-processing device is proposed, the product post-processing device includes the photopolymer 3D printing product post-processing system described in the second aspect of the present invention, as well as a post-processing cavity and a tray / carrier.

[0026] The fourth aspect of the present invention adopts the following technical solution: a computer-readable medium is provided, wherein the computer-readable medium stores a control program and post-processing prescription parameters, and when the control program is executed by a control module, the control module performs the steps of the photopolymerization 3D printing product post-processing method as described in the first aspect of the present invention.

[0027] The relevant contents of this application are explained as follows:

[0028] This invention addresses the problems in existing post-processing technologies, such as reliance on fixed times for post-processing, inability to accurately characterize the actual curing process of the workpiece, unreliable termination criteria, and insufficient curing uniformity under complex loading conditions, which prevent the fulfillment of high-precision and high-consistency batch post-processing requirements. It innovatively develops and designs a post-processing method, a post-processing system, and a post-processing device for photopolymer 3D printed products, as well as a computer-readable medium. This post-processing method and system improve curing efficiency and quality, while simultaneously monitoring environmental conditions and workpiece curing characteristics. Closed-loop control is achieved based on quantifiable curing state indices, enhancing the consistency, repeatability, and material adaptability of post-processing.

[0029] In the above solution, through the implementation of the first aspect of the technical solution of the present invention, a complete closed-loop control method for the post-processing of photopolymer 3D printed products is proposed. The overall technical concept is as follows: for multiple workpieces of the same type in the same batch, the system reads the workpiece information and loads the corresponding prescription parameters; inert gas is introduced into the post-processing chamber and preheated; only when the oxygen concentration in the chamber is... Only after continuously meeting the target threshold and maintaining the confirmation time is the irradiation phase allowed. Once in the irradiation phase, the control module performs dual-band surface reflection sampling on several representative workpieces to obtain the individual surface curing index S for each representative workpiece. i (k); then based on multiple S iThe average level and dispersion of (k) are used to calculate the batch consistency index U(k) and the comprehensive curing state index SCI(k). Finally, based on the magnitude and trend of SCI(k), the parameters of light, inert gas and fan are dynamically adjusted, and the processing ends when SCI(k) continuously and stably meets the standard. The implementation of the above post-processing methods addresses the shortcomings of existing technologies that rely solely on fixed-duration processing, which cannot characterize the true curing state of the workpiece online. This represents an upgrade from time-based control to state-based control, allowing for online quantitative monitoring of the curing process. Furthermore, to address the unreliability of oxygen inhibition, where fixed ventilation times cannot guarantee a low-oxygen environment leading to surface stickiness and insufficient curing, a continuous oxygen concentration standard entry mechanism is adopted to reliably inhibit oxygen inhibition and completely resolve the issues of surface stickiness and insufficient curing. For batch workpieces with poor curing consistency due to differences in materials, specifications, and loading, resulting in both under-curing and over-curing, this closed-loop dynamic adjustment method adapts to different workpieces and loading conditions, significantly improving batch curing consistency. Finally, to address the lack of quantifiable termination criteria, resulting in poor batch processing stability and unrepeatable or unverifiable post-processing effects, a quantifiable and verifiable termination criterion is adopted, significantly improving the consistency, repeatability, and material adaptability of post-processing.

[0030] In the above solution, through the implementation of the second aspect of the technical solution of the present invention, a post-processing system for photopolymer 3D printed products is proposed. For the setting of this hardware system, through the communication connection between the control module and each module, the control program stored in the computer-readable medium is executed to implement the post-processing method for photopolymer 3D printed products described in the first aspect of the present invention. This solves the problems of existing post-processing equipment lacking online monitoring and closed-loop control hardware, and being unable to achieve intelligent and automated post-processing, thereby providing complete hardware support, realizing the automation, closed-loop, and intelligence of the entire post-processing process, and significantly improving the post-processing effect of photopolymer 3D printed products.

[0031] In the above solution, through the implementation of the third aspect of the technical solution of the present invention, a post-processing device for photopolymer 3D printed products is proposed. Through the application of this complete device, the actual post-processing needs of photopolymer 3D printed products can be met, with high efficiency and good results.

[0032] In the above solution, through the implementation of the fourth aspect of the technical solution of the present invention, a computer-readable medium is proposed to compile the post-processing method logic into a control program, store it in the computer-readable medium, and the control module calls the program to automatically execute the entire process.

[0033] In a further technical solution, in the step of acquiring workpiece information of the workpiece to be post-processed, the workpiece information includes one or more of the following: material category, color grade, thickness grade, batch quantity, geometric complexity, and target post-processing grade. The control module acquires various workpiece information of the workpiece to be post-processed through input, recognition, or reading, achieving precise matching between the workpiece and the post-processing prescription, ensuring that different types of workpieces use optimal processing parameters, and further improving the adaptability of the solution to various materials and workpiece configurations.

[0034] In a further technical solution, surface reflection sampling is performed on representative workpieces selected from the same batch using dual-band monitoring. The number of representative workpieces is at least three, and / or the selected representative workpieces cover both the edge and center of the tray. The reflection intensity of each representative workpiece in the two monitoring bands is obtained, and the reflection intensity of each representative workpiece in the first and second monitoring bands is periodically collected and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number. This design employs more specific representative tool selection rules, avoiding situations where unreasonable selection of representative workpieces leads to sampling data that fails to represent the curing state of the entire batch of workpieces. This ensures that the sampling data obtained from the selected representative workpiece comprehensively and accurately reflects the curing state of the entire batch of workpieces. The use of a dual-band sampling method with the first and second monitoring bands makes the sampling method more standardized, providing more accurate and reliable data for subsequent calculations and ensuring monitoring accuracy.

[0035] In a further technical solution, the step of calculating the curing index of a single-piece surface based on dual-band reflection intensity specifically includes: calculating the dual-band reflection ratio Q. i (k); Based on the preset initial state ratio and target reference ratio, the dual-band reflection ratio is normalized to the 0 to 1 range to obtain the surface curing index S of a single piece. i (k), where the closer the surface curing index of a single part is to 1, the closer the representative workpiece is to the target surface post-treatment state defined by the prescription. Based on this method, the dual-band reflection ratio is calculated based on the dual-band reflection intensity. Using the preset initial state ratio and target reference ratio as benchmarks, the reflection ratio is normalized, mapping the curing degree of a single part to the 0-1 range. This digitizes and visualizes the curing state of a single workpiece, allowing for accurate determination of whether a single workpiece has reached the target post-treatment state, and providing basic data for batch index calculation.

[0036] In a further technical solution, in the step of calculating the batch consistency index and the comprehensive curing state index by combining the individual component surface curing index:

[0037] The batch consistency index U(k) is calculated based on the average and standard deviation of the surface curing index of all representative workpieces. The closer the batch consistency index U(k) is to 1, the better the curing consistency among the representative workpieces in the batch.

[0038] The comprehensive curing state index SCI(k) is a weighted fusion value that combines the batch average surface curing index and the batch consistency index. The fusion weight coefficient ranges from 0.60 to 0.85 to select the weights for batch consistency and average curing level.

[0039] By implementing the above further technical solutions, the average value and standard deviation of the surface curing index of all representative workpieces are calculated to obtain the batch consistency index. The average curing level and batch consistency are then integrated according to the preset fusion weight coefficient (0.60-0.85) to obtain the comprehensive curing state index SCI(k). This allows both the average curing level and batch consistency to be taken into account, further solving the problem of uneven curing of batch workpieces. Moreover, the fusion weight coefficient is adjustable to further adapt to the different emphasis requirements of different processes on average level or batch consistency.

[0040] In a further technical solution, the step of performing closed-loop dynamic adjustment based on the value and trend of the comprehensive curing state index specifically includes:

[0041] When the Comprehensive Curing State Index (SCI(k)) is lower than the target threshold, increase the illumination duty cycle or illuminance and maintain a high inert gas flow rate.

[0042] When the comprehensive solidification state index SCI(k) is close to the target threshold but the batch consistency index U(k) is low, increase the speed of the circulating fan in the ventilation module or extend the current processing stage.

[0043] When the Comprehensive Curing State Index (SCI(k)) meets the standard but fails to reach the required holding time, the illumination duty cycle is reduced to enter the stable holding stage.

[0044] When oxygen concentration is monitored Recovery or cavity temperature T c If the value exceeds the set range, the oxygen concentration and temperature in the post-processing chamber will be corrected first, and then the status judgment will continue.

[0045] Through the implementation of the above-mentioned further technical solutions and the implementation of the above-mentioned closed-loop dynamic adjustment rules, the control module adjusts one or more parameters such as light, inert gas, and fan in real time according to preset rules based on SCI(k), U(k), oxygen concentration, and temperature data. This further dynamically adapts to the entire curing process, avoids under-curing and over-curing, and prioritizes environmental parameters to ensure a stable processing environment with low oxygen and constant temperature, thereby further improving the reliability of the process.

[0046] In a further technical solution, the conditions for post-processing are: the Comprehensive Curing State Index (SCI(k)) is higher than the target threshold and remains above the preset end-hold duration; simultaneously, the oxygen concentration is lower than the target threshold and the chamber temperature is within a preset temperature range during this preset end-hold duration. With this design, the control module simultaneously monitors the SCI, hold duration, oxygen concentration, and chamber temperature. Only when all four conditions are met is the termination command triggered. This further quantifies, verifies, and imposes multiple constraints on the termination criteria, resulting in highly stable and repeatable batch post-processing effects that fully meet the requirements of industrial mass production.

[0047] In a further technical solution, the establishment of post-processing prescription parameters includes the following steps:

[0048] The samples were divided into several calibration groups according to workpiece type, material type, color grade, and post-processing target;

[0049] Preliminary experiments were conducted on each calibration group using different post-processing intensities.

[0050] Offline testing is performed on the pre-experimental samples. The offline testing includes at least one or more of the following: surface hardness, surface stickiness level, surface conversion rate, color difference, and dimensional change rate.

[0051] Select a set of samples that meet the target post-processing requirements, and save their corresponding dual-band reflectance ratios as Q. ref And save the process parameters that match the set of samples as the corresponding formula;

[0052] The end threshold SCI tar Set to a value that can stably meet the target post-processing requirements and has small intra-batch dispersion.

[0053] By implementing the above-mentioned technical solutions and rationally designing the process for establishing post-processing prescription parameters, the problems of post-processing prescriptions relying on experience, lacking scientific basis, having poor adaptability and reliability, and being unable to match different materials and processing targets are further avoided. This enables the scientific calibration of post-processing prescription parameters, making them more reliable and adaptable to different materials and post-processing targets, thereby further improving the versatility and reliability of this solution.

[0054] In a further technical solution, the reflection intensity of each representative workpiece is periodically collected in the first and second monitoring bands, and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number;

[0055] Calculate the dual-band reflection ratio Q i (k), , where ε is a very small positive number introduced to prevent the denominator from being zero;

[0056] In the post-processing prescription parameter establishment stage, the initial state ratio Q is pre-saved for each type of workpiece. i,0 Ratio Q to the target reference i,ref Calculate the surface curing index S of the i-th single piece. i (k), The surface curing index S of a single piece i (k) The result is limited to the interval between 0 and 1;

[0057] Let the average surface curing index of all representative workpieces at sampling time k be μ. S (k), with standard deviation σ S (k), calculate the batch consistency index U(k), , where ε is a very small positive number introduced to prevent the denominator from being zero;

[0058] The batch average surface curing index and the batch consistency index are combined to obtain the comprehensive curing state index SCI(k). , where β is the fusion weight coefficient.

[0059] Through the implementation of the above further technical solutions, by adjusting the dual-band reflection ratio Q... i (k) Single-piece surface curing index S i The explicit calculation of the batch consistency index U(k) and the comprehensive solidification state index SCI(k) ensures that the calculation process is standardized, reproducible, and easy to program, thereby guaranteeing the stable execution of the system and enabling the solution to be directly industrialized.

[0060] The fusion weighting coefficient β is a preset fusion weight used to balance the contributions of surface curing characterization and internal curing estimation. The control principle of this application is primarily based on direct surface state detection, supplemented by internal curing state estimation; therefore, β is set to be greater than 0.5. However, if β is too large, insufficient internal state correction will lead to unavoidable asynchrony between surface and internal curing. In this application, the fusion weighting coefficient β ranges from 0.60 to 0.85, which is an effective range selected through pre-calibration under representative operating conditions: when β is below 0.6, the system is overly sensitive to internal estimation terms, resulting in decreased control stability; when β is above 0.85, the system over-relies on surface signals, increasing the risk of insufficient internal curing. Therefore, this range corresponds to a reasonable operating range for achieving the technical effects of this application. In a further technical solution, the selection of representative workpieces in the multi-band monitoring module is performed according to the following conditions: more than three are selected; workpieces that can simultaneously cover the edge and center of the tray are selected; and for regularly arranged trays, workpieces are selected by dispersing them circumferentially. In the multi-band monitoring module, a fixed monitoring head is used for polling scanning, or multiple fixed monitoring heads are used for parallel sampling. This design, by selecting representative workpieces in a dispersed manner according to rules and using polling scanning or multi-probe parallel methods, completes the acquisition of reflected signals from multiple workpieces and locations, resulting in full monitoring coverage and high efficiency. It further adapts to different tray sizes and loading methods, making the system more versatile.

[0061] Due to the application of the above-mentioned solution, the technical solution of this application has the following advantages and effects compared with the prior art:

[0062] 1. Upgrade from time control to state control: This invention uses the comprehensive solidification state index SCI(k) as a unified control target and termination criterion, which significantly improves the verifiability of the post-processing process and the post-processing effect is repeatable;

[0063] 2. True inhibition of oxygen-induced polymerization: Judging by the continuous achievement of oxygen content standards rather than a fixed ventilation time, it can better ensure a true low-oxygen state when entering the irradiation stage, and completely reduce the risk of insufficient surface curing.

[0064] 3. Balancing average curing level and batch consistency: After introducing the batch consistency index U(k), it no longer only pursues the standard of individual pieces or average values, but also pursues the consistency of the entire batch of workpieces. It can balance the average curing level and batch uniformity, and avoid under-curing or over-curing.

[0065] 4. Without changing the workpiece's bearing posture: Consistency improvement is achieved solely through adjustments to environmental and irradiation parameters without rotating or flipping the workpiece. Moreover, the process parameters are dynamically adjusted exponentially to adapt to workpieces of different materials, sizes, and loads.

[0066] 5. Strong applicability: The technical solution itself is not limited to dental crowns and can be extended to the batch post-processing of other similar light-cured printed parts. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the system and equipment in Embodiments 2 and 3 of the present invention;

[0068] Figure 2 This is a schematic diagram of the post-processing method according to Embodiment 5 of the present invention;

[0069] Figure 3 This is a schematic diagram of the SCI(k) variation curve during the curing process in Embodiment 5 of the present invention;

[0070] Figure 4 This is a schematic diagram of the dual-band monitoring head in Embodiment 5 of the present invention;

[0071] Figure 5 This is a schematic diagram showing the comparison results between Embodiment Six of the present invention and the comparative example.

[0072] The component numbers in the above attached diagram are as follows:

[0073] 1. Control module;

[0074] 2. Environmental data acquisition module;

[0075] 3. Multi-band monitoring module;

[0076] 30. Dual-band monitoring head; 31. First monitoring light source; 32. Second monitoring light source; 33. Receiver;

[0077] 4. Solidified light source module;

[0078] 5. Inert gas delivery module;

[0079] 6. Ventilation module;

[0080] 7. Process the cavity;

[0081] 8. Pallets / Carriers;

[0082] 9. The workpiece being tested. Detailed Implementation

[0083] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0084] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence, nor are they intended to limit this case; they are merely used to distinguish components or operations described using the same technical terms.

[0085] The terms "connection" or "positioning" as used in this article can refer to two or more components or devices making direct physical contact with each other, or making indirect physical contact with each other, or to two or more components or devices operating or moving with each other.

[0086] The terms “include,” “including,” and “have” used in this article are all open-ended, meaning they include but are not limited to.

[0087] Unless otherwise specified, the terms used herein generally have their ordinary meaning in the context of the art, the subject matter, and the specific context. Certain terms used to describe this case will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing this case.

[0088] The terms “front,” “back,” “up,” “down,” “left,” and “right” used in this article are directional terms. In this case, they are only used to describe the positional relationship between the structures and are not intended to limit the specific direction of the protection scheme or its actual implementation.

[0089] The terminology used herein is for the purpose of describing specific embodiments only and is not intended to limit the scope of this work. Singular forms such as “a,” “this,” “this,” “the,” and “the” as used herein also include plural forms.

[0090] This invention aims to achieve the following objectives:

[0091] 1. Before entering the illumination stage, confirm that the oxygen concentration in the cavity continuously meets the target threshold to reduce the risk of oxygen inhibition polymerization;

[0092] 2. Simultaneously collect environmental conditions and workpiece surface conditions to establish a quantifiable comprehensive curing state index;

[0093] 3. Closed-loop regulation of light, temperature, inert gas, and airflow based on the comprehensive curing state index;

[0094] 4. Employ quantifiable and verifiable termination criteria to improve the consistency, repeatability, and material adaptability of post-processing.

[0095] The following will describe each specific implementation method.

[0096] Example 1: This application proposes a post-processing method for photopolymer 3D printed products, the post-processing method including:

[0097] Obtain the workpiece information of the workpiece to be post-processed, and load the matching post-processing prescription parameters;

[0098] Inert gas is introduced into the post-processing chamber and preheated. The oxygen concentration and temperature in the post-processing chamber are collected in real time. When the oxygen concentration is continuously lower than the target oxygen concentration threshold and the low oxygen confirmation time is reached, the irradiation stage is entered.

[0099] Surface reflection samples were taken from representative workpieces selected in the same batch across multiple monitoring bands to obtain the reflection intensity of each representative workpiece across multiple monitoring bands.

[0100] The surface curing index of a single piece is calculated based on the dual-band reflection intensity, and then the batch consistency index and the comprehensive curing state index are calculated by combining the surface curing index of the single piece.

[0101] Based on the value and trend of the comprehensive curing state index, a closed-loop dynamic adjustment is made, at least one or more of the following parameters: illumination parameters, inert gas flow rate, or fan parameters.

[0102] When the overall curing state index continues to meet the standard and the oxygen concentration and chamber temperature always meet the constraints, the final treatment is completed.

[0103] Through the implementation of Embodiment 1 of this invention, a complete closed-loop control method for post-processing of photopolymer 3D printed products is proposed. The overall technical concept is as follows: for multiple workpieces of the same type in the same batch, the system reads the workpiece information and loads the corresponding prescription parameters; inert gas is introduced into the post-processing chamber and preheated; only when the oxygen concentration in the chamber is... Only after continuously meeting the target threshold and maintaining the confirmation time is the irradiation phase allowed. Once in the irradiation phase, the control module performs dual-band surface reflection sampling on several representative workpieces to obtain the individual surface curing index S for each representative workpiece. i (k); then based on multiple S iThe average level and dispersion of (k) are used to calculate the batch consistency index U(k) and the comprehensive curing state index SCI(k). Finally, based on the magnitude and trend of SCI(k), the parameters of light, inert gas and fan are dynamically adjusted, and the processing ends when SCI(k) continuously and stably meets the standard. The implementation of the above post-processing methods addresses the shortcomings of existing technologies that rely solely on fixed-duration processing, which cannot characterize the true curing state of the workpiece online. This represents an upgrade from time-based control to state-based control, allowing for online quantitative monitoring of the curing process. Furthermore, to address the unreliability of oxygen inhibition, where fixed ventilation times cannot guarantee a low-oxygen environment leading to surface stickiness and insufficient curing, a continuous oxygen concentration standard entry mechanism is adopted to reliably inhibit oxygen inhibition and completely resolve the issues of surface stickiness and insufficient curing. For batch workpieces with poor curing consistency due to differences in materials, specifications, and loading, resulting in both under-curing and over-curing, this closed-loop dynamic adjustment method adapts to different workpieces and loading conditions, significantly improving batch curing consistency. Finally, to address the lack of quantifiable termination criteria, resulting in poor batch processing stability and unrepeatable or unverifiable post-processing effects, a quantifiable and verifiable termination criterion is adopted, significantly improving the consistency, repeatability, and material adaptability of post-processing.

[0104] In one embodiment of the present invention, in the step of obtaining workpiece information of the workpiece to be post-processed, the workpiece information includes one or more of the following: material category, color grade, thickness grade, batch quantity, geometric complexity, and target post-processing grade. The control module obtains various workpiece information of the workpiece to be post-processed through input, recognition, or reading, achieving precise matching between the workpiece and the post-processing prescription, ensuring that different types of workpieces use optimal processing parameters, and further improving the adaptability of the solution to various materials and workpiece configurations.

[0105] In another embodiment of the present invention, surface reflection sampling of representative workpieces selected from the same batch is performed using dual-band monitoring. The number of representative workpieces is at least three, and / or the selected representative workpieces cover the edge and center of the tray. The reflection intensity of each representative workpiece in the two monitoring bands is obtained, and the reflection intensity of each representative workpiece in the first and second monitoring bands is periodically collected and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number. This design employs more specific representative tool selection rules, avoiding situations where unreasonable selection of representative workpieces leads to sampling data that fails to represent the curing state of the entire batch of workpieces. This ensures that the sampling data obtained from the selected representative workpiece comprehensively and accurately reflects the curing state of the entire batch of workpieces. The use of a dual-band sampling method with the first and second monitoring bands makes the sampling method more standardized, providing more accurate and reliable data for subsequent calculations and ensuring monitoring accuracy.

[0106] In another embodiment of the present invention, in the step of calculating the surface curing index of a single component based on dual-band reflection intensity, the calculation of the surface curing index of a single component specifically includes: calculating the dual-band reflection ratio Q. i (k); Based on the preset initial state ratio and target reference ratio, the dual-band reflection ratio is normalized to the 0 to 1 range to obtain the surface curing index S of a single piece. i (k), where the closer the surface curing index of a single part is to 1, the closer the representative workpiece is to the target surface post-treatment state defined by the prescription. Based on this method, the dual-band reflection ratio is calculated based on the dual-band reflection intensity. Using the preset initial state ratio and target reference ratio as benchmarks, the reflection ratio is normalized, mapping the curing degree of a single part to the 0-1 range. This digitizes and visualizes the curing state of a single workpiece, allowing for accurate determination of whether a single workpiece has reached the target post-treatment state, and providing basic data for batch index calculation.

[0107] In one embodiment of the present invention, in the step of calculating the batch consistency index and the comprehensive curing state index by combining the individual surface curing index:

[0108] The batch consistency index U(k) is calculated based on the average and standard deviation of the surface curing index of all representative workpieces. The closer the batch consistency index U(k) is to 1, the better the curing consistency among the representative workpieces in the batch.

[0109] The comprehensive curing state index SCI(k) is a weighted fusion value that combines the batch average surface curing index and the batch consistency index. The fusion weight coefficient ranges from 0.60 to 0.85 to select the weights for batch consistency and average curing level.

[0110] In another embodiment of the present invention, by statistically analyzing the surface curing index of all representative workpieces, calculating the average value and standard deviation, a batch consistency index is obtained. The average curing level and batch consistency are then combined according to a preset fusion weighting coefficient (0.60-0.85) to obtain the comprehensive curing state index SCI(k). This allows for the consideration of both the average curing level of the batch and the consistency within the batch, further thoroughly solving the problem of uneven curing of batch workpieces. Moreover, the fusion weighting coefficient is adjustable to further adapt to the different emphasis requirements of different processes on average level or batch consistency.

[0111] In another embodiment of the present invention, in the step of performing closed-loop dynamic adjustment based on the value and trend of the comprehensive curing state index, the closed-loop dynamic adjustment specifically includes:

[0112] When the Comprehensive Curing State Index (SCI(k)) is lower than the target threshold, increase the illumination duty cycle or illuminance and maintain a high inert gas flow rate.

[0113] When the comprehensive solidification state index SCI(k) is close to the target threshold but the batch consistency index U(k) is low, increase the speed of the circulating fan in the ventilation module or extend the current processing stage.

[0114] When the Comprehensive Curing State Index (SCI(k)) meets the standard but fails to reach the required holding time, the illumination duty cycle is reduced to enter the stable holding stage.

[0115] When oxygen concentration is monitored Recovery or cavity temperature T c If the condition exceeds the set range, the oxygen concentration and temperature in the post-processing chamber will be corrected first, and then the status judgment will continue.

[0116] Through the implementation of the above-mentioned further technical solutions and the implementation of the above-mentioned closed-loop dynamic adjustment rules, the control module adjusts one or more parameters such as light, inert gas, and fan in real time according to preset rules based on SCI(k), U(k), oxygen concentration, and temperature data. This further dynamically adapts to the entire curing process, avoids under-curing and over-curing, and prioritizes environmental parameters to ensure a stable processing environment with low oxygen and constant temperature, thereby further improving the reliability of the process.

[0117] In one embodiment of the present invention, during post-processing, the conditions for post-processing are: the Comprehensive Curing State Index (SCI(k)) is higher than the target threshold and remains for a preset end-holding time; simultaneously, during the preset end-holding time, the oxygen concentration is lower than the target threshold and the chamber temperature is within a preset temperature range. With this design, the control module simultaneously monitors the SCI, holding time, oxygen concentration, and chamber temperature. Only when all four conditions are met is the termination command triggered. This further quantifies, verifies, and imposes multiple constraints on the termination criteria, resulting in highly stable and repeatable batch post-processing effects, fully meeting the requirements of industrial mass production.

[0118] In another embodiment of the present invention, the establishment of post-processing prescription parameters includes the following steps:

[0119] The samples were divided into several calibration groups according to workpiece type, material type, color grade, and post-processing target;

[0120] Preliminary experiments were conducted on each calibration group using different post-processing intensities.

[0121] Offline testing is performed on the pre-experimental samples. The offline testing includes at least one or more of the following: surface hardness, surface stickiness level, surface conversion rate, color difference, and dimensional change rate.

[0122] Select a set of samples that meet the target post-processing requirements, and save their corresponding dual-band reflectance ratios as Q. refAnd save the process parameters that match the set of samples as the corresponding formula;

[0123] The end threshold SCI tar Set to a value that can stably meet the target post-processing requirements and has small intra-batch dispersion.

[0124] By implementing the above-mentioned technical solutions and rationally designing the process for establishing post-processing prescription parameters, the problems of post-processing prescriptions relying on experience, lacking scientific basis, having poor adaptability and reliability, and being unable to match different materials and processing targets are further avoided. This enables the scientific calibration of post-processing prescription parameters, making them more reliable and adaptable to different materials and post-processing targets, thereby further improving the versatility and reliability of this solution.

[0125] In another embodiment of the present invention, the reflection intensity of each representative workpiece under the first monitoring band and the second monitoring band is periodically collected and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number;

[0126] Calculate the dual-band reflection ratio Q i (k), , where ε is a very small positive number introduced to prevent the denominator from being zero;

[0127] In the post-processing prescription parameter establishment stage, the initial state ratio Q is pre-saved for each type of workpiece. i,0 Ratio Q to the target reference i,ref Calculate the surface curing index S of the i-th single piece. i (k), The surface curing index S of a single piece i (k) The result is limited to the interval between 0 and 1;

[0128] Let the average surface curing index of all representative workpieces at sampling time k be μ. S (k), with standard deviation σ S (k), calculate the batch consistency index U(k), , where ε is a very small positive number introduced to prevent the denominator from being zero;

[0129] The batch average surface curing index and the batch consistency index are combined to obtain the comprehensive curing state index SCI(k). , where β is the fusion weight coefficient.

[0130] Through the implementation of the above further technical solutions, by adjusting the dual-band reflection ratio Q... i (k) Single-piece surface curing index S iThe explicit calculation of the batch consistency index U(k) and the comprehensive solidification state index SCI(k) ensures that the calculation process is standardized, reproducible, and easy to program, thereby guaranteeing the stable execution of the system and enabling the solution to be directly industrialized.

[0131] Example 2: This application proposes a post-processing system for photopolymer 3D printed products, such as... Figure 1 As shown, the system includes a control module 1 and an environmental acquisition module 2, a multi-band monitoring module 3, a curing light source module 4, an inert gas delivery module 5, and a ventilation module 6, which are communicatively connected to the control module 1.

[0132] The control module is used to execute a control program stored in a computer-readable medium to implement the photopolymerization 3D printing product post-processing method described in Embodiment 1;

[0133] The environmental acquisition module 2 is used to collect the oxygen concentration and temperature inside the post-processing chamber 7 in real time and transmit them to the control module.

[0134] The multi-band monitoring module 3 is used to sample the surface reflection of representative workpieces selected in the same batch across multiple monitoring bands, and to obtain the reflection intensity of each representative workpiece in multiple monitoring bands.

[0135] The curing light source module 4 is used to irradiate with different light intensities according to the instructions of the control module. Figure 1 The arrows in the image indicate light illuminating the scene.

[0136] The inert gas delivery module 5 is used to deliver inert gas at different flow rates according to the instructions of the control module.

[0137] The ventilation module 6 is used to perform ventilation circulation at different flow rates according to the instructions of the control module.

[0138] Through the implementation of Embodiment 2 of the present invention, a post-processing system for photopolymer 3D printed products is proposed. For the configuration of this hardware system, through the communication connection between the control module 1 and each module, the control program stored in the computer-readable medium is executed to implement the post-processing method for photopolymer 3D printed products described in the first aspect of the present invention. This solves the problems of existing post-processing equipment lacking online monitoring and closed-loop control hardware, and being unable to achieve intelligent and automated post-processing. It provides complete hardware support, realizes the automation, closed-loop, and intelligence of the entire post-processing process, and significantly improves the post-processing effect of photopolymer 3D printed products.

[0139] In one embodiment of the present invention, the multi-band monitoring module 3 selects representative workpieces according to the following conditions: more than three are selected; workpieces that can simultaneously cover the edge and center of the tray are selected; and for regularly arranged trays, workpieces are selected that are distributed circumferentially. In the multi-band monitoring module 3, a fixed monitoring head is used for polling scanning, or multiple fixed monitoring heads are used for parallel sampling. With this design, representative workpieces are selected according to rules and dispersedly. Polling scanning or multi-probe parallel sampling is used to complete the acquisition of reflected signals from multiple workpieces and locations, resulting in full monitoring coverage and high efficiency. This further adapts to different tray sizes and loading methods, making the system more versatile.

[0140] Example 3: This application proposes a post-processing device for photopolymer 3D printed products, referencing... Figure 1 As shown, the product post-processing equipment includes the photopolymerization 3D printing product post-processing system described in Embodiment 2 of the present invention, as well as a post-processing cavity 7 and a tray / carrier 8.

[0141] Through the implementation of Embodiment 3 of the present invention, a post-processing device for photopolymer 3D printed products is proposed. The application of this complete device can meet the actual post-processing needs of photopolymer 3D printed products, with high efficiency and good results.

[0142] Example 4: This application proposes a computer-readable medium storing a control program and post-processing prescription parameters. When the control program is executed by a control module, the control module performs the steps of the photopolymerization 3D printing product post-processing method as described in Example 1 of this invention.

[0143] Through the implementation of Embodiment 4 of the present invention, a computer-readable medium is proposed to compile the post-processing method logic into a control program, store it in the computer-readable medium, and the control module calls the program to automatically execute the entire process.

[0144] Example 5: Hereinafter, taking dual-band sampling as an example, we will further explain the post-processing method steps, system, equipment and other implementation methods of the present invention.

[0145] The post-processing method flow of Embodiment 5 of the present invention is as follows: Figure 2 As shown, the steps may include the following.

[0146] S100. Obtain workpiece information and load prescription parameters:

[0147] The control module acquires the workpiece information to be post-processed. This information may include material type, color grade, thickness grade, batch quantity, geometric complexity, and target post-processing level. Based on this workpiece information, the control module loads the corresponding post-processing prescription parameters from the memory.

[0148] The establishment of post-processing prescription parameters includes the following steps:

[0149] S110. Divide the samples into several calibration groups according to workpiece type, material type, color grade and post-processing target;

[0150] S120. Conduct preliminary experiments for each calibration group using different post-processing intensities;

[0151] S130. Perform offline testing on the pre-experimental sample, wherein the offline testing includes at least one or more of the following: surface hardness, surface stickiness level, surface conversion rate, color difference, and dimensional change rate.

[0152] S140. Select a set of samples that meet the post-processing requirements of the target, and save their corresponding dual-band reflectance ratio as Q. ref And save the process parameters that match the set of samples as the corresponding formula;

[0153] S150, Set the end threshold SCI tar Set to a value that can stably meet the target post-processing requirements and has small intra-batch dispersion.

[0154] S200, inert gas replacement and preheating:

[0155] Inert gas is introduced into the post-processing chamber, and the heating module is controlled to maintain the chamber temperature at the required level. The control module monitors the chamber oxygen concentration in real time. With cavity temperature T c Only when And the continuous holding time is not less than t con Only when the time is right can the pre-curing stage be started, where C tar For the set target oxygen concentration threshold, t con This is the preset duration for confirming low oxygen levels. If the oxygen concentration recovers during this period, the timer will restart.

[0156] S300 represents dual-band sampling of the workpiece:

[0157] Several representative workpieces are selected from the same batch of workpieces. Preferably, the number of representative workpieces is no less than 3, more preferably 3 to 8; preferably, both the edge and center of the tray are covered. The control module periodically collects the reflection intensity of each representative workpiece under the first monitoring band and the second monitoring band, denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number.

[0158] S400, calculate the state index and perform closed-loop dynamic adjustment:

[0159] Based on the acquired dual-band reflection response, the surface curing index S of each representative workpiece is calculated. i (k); then based on the S of all representative workpieces i (k) Calculate the batch consistency index U(k) and the comprehensive curing state index SCI(k). Based on the numerical range and trend of SCI(k), the control module adjusts one or more of the following: light intensity, duty cycle, strobe frequency, inert gas flow rate, and circulating fan speed.

[0160] S500, Termination Judgment and Exit:

[0161] When SCI(k) is not lower than the termination threshold SCI tar And the duration is not less than the preset end hold time t hold Meanwhile, during this period Never higher than C tar T c Always within the preset cavity temperature range [T] min ,T max [When the time is up, the irradiation treatment ends. After the treatment is complete, inert gas protection can be maintained for a short period of time, and the chamber can be opened to remove the contents after the temperature drops.]

[0162] The calculation process for the four quantities involved in the state calculation in this scheme will be explained below.

[0163] Dual-band reflection ratio Q i (k):

[0164] For the i-th representative workpiece, at the k-th sampling, the dual-band reflection ratio Q i (k) can be calculated using the following formula:

[0165] ;

[0166] Here, ε is a very small positive number introduced to prevent the denominator from being zero.

[0167] Single-piece surface curing index S i (k):

[0168] During the prescription creation phase, the initial state ratio Q is pre-saved for each type of workpiece. i,0 Ratio Q to the target reference i,ref During post-processing, the surface curing index S of the i-th representative workpiece is... i (k) can be calculated using the following formula, with the result limited to the interval between 0 and 1:

[0169] ;

[0170] Among them, S iThe closer (k) is to 1, the closer the representative workpiece is to the target surface post-processing state defined by the prescription.

[0171] Batch consistency index U(k):

[0172] Let the average surface curing index of all representative workpieces at sampling time k be μ. S (k), with standard deviation σ S If (k), then the batch consistency index U(k) can be calculated using the following formula:

[0173] ;

[0174] The closer U(k) is to 1, the better the consistency among the representative workpieces in the batch.

[0175] Comprehensive Curing State Index (SCI(k)):

[0176] The batch average surface curing level and the consistency index are combined to obtain the comprehensive curing state index SCI(k):

[0177] ;

[0178] Wherein, β is the fusion weighting coefficient, with a preferred value range of 0.60 to 0.85. When the process focuses more on batch consistency, β can be reduced; when the average curing level is more important, β can be increased.

[0179] In this invention application, for representative material systems, wall thickness / size grades, loading densities, and target post-processing quality requirements, several candidate β values ​​are first selected for calibration experiments. Then, the consistency of the post-processing endpoint, surface residue, hardness compliance, overheating risk, and batch-to-batch stability are compared. Finally, a continuous effective range is selected. Specifically, when β is below 0.6, the proportion of internal estimation terms is too high, making the system more sensitive to model errors and prone to stage switching lag or fluctuations. When β is above 0.85, the system over-relies on surface signals, easily leading to the risk that the surface may meet the standards while internal synchronization is insufficient. Thus, an effective working range of 0.6-0.85 is obtained.

[0180] In a specific embodiment of the present invention, the post-processing prescription parameters stored in the computer-readable medium at least include the parameters shown in Table 1:

[0181] Table 1

[0182]

[0183] In the dual-band embodiment, the control module can perform adjustments according to the following rules:

[0184] 1. When SCI(k) <SCI tarWhen the value is -0.10, increase the duty cycle or illuminance while maintaining a high inert gas flow rate;

[0185] 2. When SCI(k) is close to SCI tar However, when U(k) is low, priority should be given to increasing the speed of the circulating fan or extending the current stage, rather than simply continuing to increase the illuminance;

[0186] 3. When SCI(k) ≥ SCI tar However, t has not yet been satisfied. hold When entering a stable holding phase, it is preferable to reduce the duty cycle to avoid localized over-curing;

[0187] 4. When detected Rebound or T c When the condition exceeds the set range, the environmental conditions should be corrected first, and then the status judgment should continue.

[0188] This document summarizes the post-processing steps for photopolymer 3D printed products. A schematic diagram of the SCI(k) variation curve during the curing process can be found in the provided information. Figure 3 As shown, the time for introducing inert gas (displacement) into the pre-treatment chamber and for preheating and pre-curing is relatively short. After entering the second half of the main curing stage, the comprehensive curing state index continues to meet the standard and can maintain the judgment constraint for a certain period of time.

[0189] Based on the above dual-band embodiment, when the control module executes the program stored in the memory, it can achieve the following functions:

[0190] Obtain workpiece information and load prescription;

[0191] judge Does C satisfy continuously? tar And time it;

[0192] According to the sampling period Δt s Collect dual-band reflection data for each representative workpiece;

[0193] Calculate Q i (k), S i (k), U(k) and SCI(k);

[0194] Adjust illuminance, duty cycle, inert gas flow rate, and fan speed according to threshold rules;

[0195] The process ends when SCI(k) consistently meets the requirements and environmental conditions satisfy the constraints.

[0196] In a preferred embodiment of the present invention, the representative workpiece is selected according to the following principles:

[0197] The quantity shall be no less than 3, preferably 4 to 8;

[0198] Ideally, both the edge and center of the tray should be covered.

[0199] For regularly arranged pallets, it is preferable to distribute representative workpieces in a circumferential direction;

[0200] For large pallets, a fixed monitoring head can be used for polling scanning, or multiple fixed monitoring heads can be used for parallel sampling.

[0201] In the dual-band embodiment, the multi-band monitoring module 3 employs a dual-band monitoring structure. The first monitoring band can be selected as 620 to 700 nm, and the second monitoring band can be selected as 800 to 900 nm. Both monitoring bands are separated from the curing band, and sampling is preferably performed during the curing pulse interval to reduce curing light crosstalk. (Reference) Figure 4 As shown, the dual-band monitoring head 30 of the multi-band monitoring module 3 (dual-band monitoring structure) may include a first monitoring light source 31, a second monitoring light source 32, and a receiver 33. The receiver 33 may be a photodiode or a small area array sensor. The light emitted by the first monitoring light source 31 and the second monitoring light source 32 is reflected by the surface of the workpiece 9 being measured and then received by the receiver 33. The receiver 33 transmits the collected signal to the control module 1. The control module 1 filters and normalizes the collected signal before using it for calculation.

[0202] Example 6 illustrates the batch post-processing of multiple identical dental crowns (3D printed parts) as an example of batch post-processing of dental crowns (Example 6). In this example, 12 identical dental crowns are post-processed using the technical solution of the present invention, and 12 identical dental crowns are post-processed using a conventional timed long-term light curing chamber.

[0203] In this embodiment of batch post-processing of dental crowns, 12 dental crowns from the same batch, made of the same material, of the same color grade, printed in the same direction, and with the same geometric configuration were selected as the workpieces to be post-processed. After printing, they were first cleaned and dried using routine methods, and then loaded onto a tray at a fixed station.

[0204] The post-processing equipment adopts the scheme described in Embodiment 2 of the present invention, and the main parameters are as follows: the curing wavelength is 405 nm; the cavity is replaced with nitrogen; the control module performs data sampling once every 10 seconds; the number of representative workpieces is 6, which are distributed at the edge and middle of the tray respectively.

[0205] In this embodiment of batch post-processing of dental crowns, the first monitoring wavelength was selected as 660±10 nm, and the second monitoring wavelength was selected as 850±20 nm. Dual-band monitoring was performed using time-division sampling during the curing pulse intervals to reduce curing light crosstalk. β=0.75 was used in the formulation.

[0206] A “Dental Crown Resin - Same Type Batch Post-Processing” prescription is stored in a computer-readable medium. The parameters of the post-processing prescription matched under this workpiece information are shown in Table 2.

[0207] Table 2

[0208]

[0209] The specific steps of this embodiment of batch post-processing for dental crowns are as follows:

[0210] 1. Loading and prescription matching: Place 12 identical crowns into a tray at a fixed position, and the control module loads the "crown resin - same type batch post-processing" prescription;

[0211] 2. Nitrogen purging and preheating: Purging is performed with nitrogen at a flow rate of 12 L / min, and preheating is carried out simultaneously; when After remaining below 0.30% for 45 consecutive seconds, the product enters the pre-curing stage.

[0212] 3. Pre-curing stage: Perform pre-curing according to the parameters in Table 2 for 90 seconds; collect and calculate the dual-band reflectance values ​​Q of 6 representative crowns every 10 seconds. i (k), and calculate S i (k), U(k) and SCI(k);

[0213] 4. Main curing stage: Switch to main curing parameters; when SCI(k) < 0.80, increase the duty cycle by 5 percentage points and maintain high nitrogen flow rate; when SCI(k) ≥ 0.90 but has not lasted for 30 s, reduce the duty cycle to 50%, increase the circulating fan speed to 55%, and enter the stable holding stage.

[0214] 5. Termination Decision: When SCI(k) is not lower than 0.92 for 30 consecutive seconds, and within that duration... Always below 0.30%, T c The treatment should be terminated when the temperature remains between 45°C and 49°C.

[0215] The process data for the specific steps of the above-described embodiment of batch post-processing of dental crowns are shown in Table 3.

[0216] Table 3

[0217]

[0218] Following the specific steps of the above-described batch post-processing embodiment for dental crowns, after post-processing of the 12 crowns in this batch, offline testing was performed on all 12 crowns. The offline testing measured surface hardness, surface tackiness level, and overall color difference. Surface tackiness level was recorded from 0 to 3, where 0 indicates no tackiness and 3 indicates significant tackiness. The offline testing results are shown in Table 4.

[0219] Table 4

[0220]

[0221] As shown in Table 4, none of the 12 crowns in this embodiment showed any surface stickiness, and the intra-batch dispersion of surface hardness and overall color difference was small. Therefore, it has good consistency of the entire batch of workpieces and also has a good curing level.

[0222] In the process of processing the same 12 identical crowns using a conventional timed long-term light curing box, the crowns used are the same as those in the above-mentioned crown batch post-processing example (Example 6), and the cleaning, drying and loading methods are the same, only the post-processing equipment and post-processing methods are changed.

[0223] This conventional timed long-term light curing chamber uses a single fixed program: 405 nm light illumination for 300 s, without monitoring oxygen concentration, representative workpiece reflection signals, SCI calculation, or adjusting light or environmental parameters according to processing progress. After processing, offline detection was performed using the same method as in the batch post-processing example for dental crowns (Example Six), and the comparative offline detection results are shown in Table 5.

[0224] Table 5

[0225]

[0226] From Table 5 and Figure 5 As can be seen, the embodiments of the present invention do not simply extend or shorten the processing time, but rather achieve the purpose of the present invention through a combined mechanism of low oxygen continuous confirmation, dual-band monitoring of representative workpieces, batch consistency index, and comprehensive curing state index to end the determination, resulting in higher average hardness, smaller batch dispersion, significantly reduced surface stickiness, and more stable overall color difference control.

[0227] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A post-processing method for photopolymer 3D printed products, characterized in that, The post-processing method includes: Obtain the workpiece information of the workpiece to be post-processed, and load the matching post-processing prescription parameters; Inert gas is introduced into the post-processing chamber and preheated. The oxygen concentration and temperature in the post-processing chamber are collected in real time. When the oxygen concentration is continuously lower than the target oxygen concentration threshold and the low oxygen confirmation time is reached, the irradiation stage is entered. Surface reflection samples were taken from representative workpieces selected in the same batch across multiple monitoring bands to obtain the reflection intensity of each representative workpiece across multiple monitoring bands. The surface curing index of a single piece is calculated based on the dual-band reflection intensity. Then, the batch consistency index and the comprehensive curing state index are calculated by combining the surface curing index of the single piece. The batch consistency index U(k) is calculated based on the average value and standard deviation of the surface curing index of all representative workpieces. The closer the batch consistency index U(k) is to 1, the better the curing consistency among the representative workpieces in the batch. The comprehensive curing state index SCI(k) is a weighted fusion value that combines the average surface curing index of the batch and the batch consistency index to select the weights for the overall batch consistency and the average curing level. Based on the value and trend of the comprehensive curing state index, a closed-loop dynamic adjustment is made, at least one or more of the following parameters: illumination parameters, inert gas flow rate, or fan parameters. When the overall curing state index continues to meet the standard and the oxygen concentration and chamber temperature always meet the constraints, the final treatment is completed.

2. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that: In the step of obtaining workpiece information of the workpiece to be post-processed, the workpiece information includes one or more of the following: material category, color grade, thickness grade, batch quantity, geometric complexity, and target post-processing grade.

3. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that: Surface reflection sampling is performed on representative workpieces selected from the same batch using dual-band monitoring. The number of representative workpieces is at least three, and / or the selected representative workpieces cover both the edge and center of the tray. The reflection intensity of each representative workpiece in the two monitoring bands is obtained. The reflection intensity of each representative workpiece in the first and second monitoring bands is periodically collected and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number.

4. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that: In the step of calculating the curing index of a single-piece surface based on dual-band reflection intensity, the specific steps of calculating the curing index of a single-piece surface include: Calculate the dual-band reflection ratio Q i (k); Based on the preset initial state ratio and target reference ratio, the dual-band reflection ratio is normalized to the 0 to 1 range to obtain the surface curing index S of a single piece. i (k), where the closer the surface curing index of a single piece is to 1, the closer the representative workpiece is to the target surface post-treatment state defined by the prescription.

5. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that, In the step of fusing the batch average surface curing index and the batch consistency index to obtain the comprehensive curing state index SCI(k): The fusion weighting coefficient ranges from 0.60 to 0.

85.

6. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that, In the step of performing closed-loop dynamic adjustment based on the value and trend of the comprehensive curing state index, the closed-loop dynamic adjustment specifically includes: When the Comprehensive Curing State Index (SCI(k)) is lower than the target threshold, increase the illumination duty cycle or illuminance and maintain a high inert gas flow rate. When the comprehensive solidification state index SCI(k) is close to the target threshold but the batch consistency index U(k) is low, increase the speed of the circulating fan in the ventilation module or extend the current processing stage. When the Comprehensive Curing State Index (SCI(k)) meets the standard but fails to reach the required holding time, the illumination duty cycle is reduced to enter the stable holding stage. When oxygen concentration is monitored Recovery or cavity temperature T c If the condition exceeds the set range, the oxygen concentration and temperature in the post-processing chamber will be corrected first, and then the status judgment will continue.

7. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that, During post-processing, the conditions for post-processing are: The overall curing state index (SCI(k)) is higher than the target threshold and continues for a preset end holding time. At the same time, during the preset end holding time, the oxygen concentration is lower than the target threshold and the cavity temperature is within the preset temperature range.

8. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that, The establishment of post-processing prescription parameters includes the following steps: The samples were divided into several calibration groups according to workpiece type, material type, color grade, and post-processing target; Preliminary experiments were conducted on each calibration group using different post-processing intensities. Offline testing is performed on the pre-experimental samples. The offline testing includes at least one or more of the following: surface hardness, surface stickiness level, surface conversion rate, color difference, and dimensional change rate. Select a set of samples that meet the target post-processing requirements, and save their corresponding dual-band reflectance ratios as Q. ref And save the process parameters that match the set of samples as the corresponding formula; The end threshold SCI tar Set to a value that can stably meet the target post-processing requirements and has small intra-batch dispersion.

9. The post-processing method for photopolymer 3D printed products according to claim 1, characterized in that: The reflection intensity of each representative workpiece is periodically collected in the first and second monitoring bands, and denoted as R. i,1 (k) and R i,2 (k), where i represents the workpiece number and k represents the sampling time number; Calculate the dual-band reflection ratio Q i (k), , where ε is a very small positive number introduced to prevent the denominator from being zero; In the post-processing prescription parameter establishment stage, the initial state ratio Q is pre-saved for each type of workpiece. i,0 Ratio Q to the target reference i,ref Calculate the surface curing index S of the i-th single piece. i (k), The surface curing index S of a single piece i (k) The result is limited to the interval between 0 and 1; Let the average surface curing index of all representative workpieces at sampling time k be μ. S (k), with standard deviation σ S (k), calculate the batch consistency index U(k), , where ε is a very small positive number introduced to prevent the denominator from being zero; The batch average surface curing index and the batch consistency index are combined to obtain the comprehensive curing state index SCI(k). , where β is the fusion weight coefficient.

10. A post-processing system for photopolymer 3D printed products, characterized in that: The system includes a control module and an environmental acquisition module, a multi-band monitoring module, a curing light source module, an inert gas delivery module, and a ventilation module that are communicatively connected to the control module. The control module is used to execute a control program stored in a computer-readable medium to implement the post-processing method for photopolymer 3D printed products according to any one of claims 1 to 9; The environmental acquisition module is used to collect the oxygen concentration and temperature inside the post-processing chamber in real time and transmit them to the control module. The multi-band monitoring module is used to sample the surface reflection of representative workpieces selected in the same batch across multiple monitoring bands, and to obtain the reflection intensity of each representative workpiece in multiple monitoring bands. The curing light source module is used to irradiate with different light intensities according to the instructions of the control module; The inert gas delivery module is used to deliver inert gas at different flow rates according to the instructions of the control module. The ventilation module is used to perform ventilation circulation at different flow rates according to the instructions of the control module.

11. The photopolymerization 3D printing product post-processing system according to claim 10, characterized in that: In the multi-band monitoring module, the selection of representative workpieces is performed according to the following conditions: more than three are selected, the workpieces that can simultaneously cover the edge and middle of the tray are selected, and for regularly arranged trays, the workpieces are selected to be distributed circumferentially. In the multi-band monitoring module, a fixed monitoring head is used for polling scanning, or multiple fixed monitoring heads are used for parallel sampling.

12. A post-processing device for photopolymer 3D printed products, characterized in that: The product post-processing equipment includes the photopolymer 3D printed product post-processing system as described in claim 10 or 11, as well as a post-processing cavity and a tray / carrier.

13. A computer-readable medium, characterized in that: The computer-readable medium stores a control program and post-processing prescription parameters. When the control program is executed by the control module, the control module performs the steps of the photopolymerization 3D printing product post-processing method as described in any one of claims 1 to 9.

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