A drying method and system for acrylic sheet processing

Abstract

The present invention relates to the technical field of acrylic plate drying, and particularly to a drying method and system for acrylic plate processing. Among them, the method includes the following steps: Step 1 Pretreatment and parameter collection: Clean the surface of the high-precision optical acrylic plate and spray an anti-moisture absorption coating, and simultaneously collect the plate thickness, initial humidity distribution and transmittance reference value; Step 2 Dynamic zoning and humidity-temperature coordinated control; Step 3 Stress coordinated drying in stages; Step 4 Post-treatment balance: Let the plate stand until the ambient temperature is balanced, and maintain a micro air flow cycle to inhibit humidity rebound. Through precise humidity gradient and temperature control, the deformation and stress concentration in the acrylic plate processing can be effectively reduced, and the optical performance and physical stability of the final product can be improved. At the same time, the multi-sensor configuration and data fusion method of the system greatly improve the accuracy and controllability of the drying process, avoid possible quality problems, and improve production efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of acrylic plate drying, and particularly relates to a drying method and system for acrylic plate processing. Background Art

[0002] High-precision optical acrylic plates (such as light guide plates, optical lenses, AR / VR display panels, etc.) have strict requirements for light transmittance, refractive index uniformity, and surface flatness, and their optical properties are extremely susceptible to environmental humidity. During the processing, moisture absorption or insufficient drying of the plates will cause the following problems:

[0003] Light transmittance attenuation: Residual moisture forms micron-scale scattering centers inside the plate, causing light to be diffusely reflected and reducing the light transmittance (especially significantly affecting the visible light band with wavelengths of 400 - 700 nm);

[0004] Refractive index fluctuation: After moisture absorption, the distribution of hydrogen bonds between acrylic resin molecular chains changes, causing local refractive index differences and resulting in imaging distortion or optical path deviation;

[0005] Surface microstructure deterioration: Non-uniform shrinkage caused by humidity gradients will form microcracks on the surface of nanoimprinting or coating, exacerbating light scattering and increasing reflectivity.

[0006] Currently, the drying technology for high-precision optical plates still has the following bottlenecks:

[0007] (1) Defects in static humidity field regulation: Traditional processes use a constant humidity field for drying, which cannot adapt to the spatial differences in plate thickness and moisture absorption characteristics. For example, the existing technology controls humidity through uniform hot air circulation, but the actual humidity in the edge area is significantly higher than that in the central area due to faster heat dissipation, resulting in a set percentage decrease in the light transmittance at the edge of the plate compared to the central area, and unable to meet the full-area consistency requirements of optical devices.

[0008] (2) Lack of optical property monitoring: The determination of the drying end point in the existing technology relies on humidity sensors or timing control, lacking online monitoring of optical parameters such as light transmittance and surface topography. Summary of the Invention

[0009] To solve the above problems, the present invention provides a drying method and system for acrylic plate processing. Among them, a drying method for acrylic plate processing includes the following steps:

[0010] Step 1: Pretreatment and parameter collection: Clean the surface of the high-precision optical acrylic plate and spray an anti-moisture absorption coating, and simultaneously collect the plate thickness, initial humidity distribution, and light transmittance reference value;

[0011] Step 2: Dynamic zoning and humidity-temperature coordinated control: According to the thickness and initial humidity distribution data, the drying area is divided into multiple independent sub-areas, and a humidity gradient target value decreasing from the edge to the center is generated. Dynamic humidity regulation is achieved by injecting mixed gas and independent temperature control of the sub-areas;

[0012] Step 3: Stress-coordinated drying in stages: Rapid dehumidification, homogenization humidity control and final drying calibration are performed in sequence. Internal stress is eliminated through gradient heating, dynamic orientation of guide plates and cooling reverse airflow. The endpoint judgment must simultaneously meet the humidity standard deviation, transmittance deviation and temperature uniformity thresholds.

[0013] Step 4: Post-treatment balance: Leave the board to balance to ambient temperature and maintain a small amount of air circulation to suppress humidity rebound.

[0014] Preferably, the specific operations of step 1 include:

[0015] Ultrasonic cleaning and nitrogen purging were used to remove surface impurities and droplets, and the cleaning time was a function of the plate thickness;

[0016] The surface of the anti-hygroscopic coating is scanned in real time by a laser interferometer. If the local thickness deviation is detected to exceed the set threshold, an offset of the correction path is generated. The offset is calculated by the area and position coordinates of the deviation area.

[0017] Four sets of high-precision humidity sensors are arranged in the drying box, located at set distances above, below, on the left and on the right of the board, to collect initial humidity distribution data and calculate the standard deviation;

[0018] Use a non-contact laser thickness gauge to scan the thickness data at intervals along the length of the plate. The scanning interval is dynamically determined by the ratio of the plate area to the thickness. After eliminating the edge distortion data, the average thickness value is calculated.

[0019] The initial transmittance is measured by a spectrophotometer under a standard light source. During the measurement, the surface of the plate is at a set angle to the light source. The allowable error of the transmittance reference value is dynamically determined by the target optical performance index.

[0020] Preferably, the generation logic of the humidity gradient target value in step 2 includes:

[0021] If the standard deviation of the initial humidity distribution exceeds the set threshold, the humidity target value of the edge area is set to a set ratio of the humidity in the central area, and the ratio is dynamically determined by the experimental fitting curve of thickness and moisture absorption rate of the board;

[0022] The mixed gas is a mixture of dry nitrogen and controllable steam in proportion. The mixing ratio is dynamically adjusted according to the difference between the current humidity and the target humidity. The greater the difference, the higher the proportion of nitrogen.

[0023] The calculation formula for the temperature set value of independent heating for each sub-region is: the difference between the target humidity and the current humidity multiplied by the thickness correction coefficient, and the correction coefficient is generated from the mapping relationship between the humidity difference and the sheet deformation amount in historical production data.

[0024] Preferably, the staged stress collaborative drying in step 3 includes:

[0025] Fast dehumidification stage: Start the high wind speed circulation mode. The air flow speed is controlled by the ratio of the difference between the initial humidity and the target humidity. The greater the difference, the higher the wind speed; the temperature rises in a stepped manner, and the temperature rise amplitude in each stage is determined by the product of the current humidity gradient and the reciprocal of the thickness. The humidity gradient is calculated by the ratio of the humidity difference between adjacent sub-regions to the distance;

[0026] Homogenization humidity control stage: When the overall humidity of the sheet drops to a preset critical value, switch to the low wind speed constant temperature mode, and the deflector is switched to the horizontal oscillation mode. The oscillation frequency increases linearly with the humidity drop rate, and the frequency increase amplitude is determined by the product relationship between the rate change amplitude and the thickness;

[0027] Final drying calibration stage: Turn off the heating element and turn on the cooling system. The cooling wind speed is adjusted proportionally according to the thickness. The greater the thickness, the lower the wind speed; the direction of the cooling air flow is set at a reverse angle to the air flow direction in the drying stage, and the reverse angle is determined by the output value of the residual stress distribution model, and the model is constructed through the mapping relationship between the thickness and the historical stress concentration area.

[0028] Preferably, the method for suppressing local overheating in the fast dehumidification stage includes:

[0029] Real-time monitor the surface temperature distribution of the sheet by an infrared thermal imager. If a local temperature mutation area is detected, that is, a continuous area where the temperature change rate exceeds the set threshold, immediately reduce the heating power of the corresponding sub-region to a set proportion of the initial value and trigger local air flow acceleration;

[0030] The local air flow acceleration time is a function of the area of the mutation area. After the acceleration time ends, the temperature rise amplitude resumes to a set proportion of the original calculated value, and the proportion value is determined by the product of the duration and area of the mutation area;

[0031] If the overheating suppression is continuously triggered twice in the same sub-region, lock the temperature of the sub-region and trigger an alarm.

[0032] Preferably, the oscillation frequency control logic in the homogenization humidity control stage includes:

[0033] The initial value of the oscillation frequency is determined by the product relationship between the sheet thickness and the current humidity drop rate;

[0034] Real-time monitor the humidity drop rate. If the rate increases, the oscillation frequency rises linearly according to the rate change amplitude;

[0035] The deformation rate is monitored by a strain gauge array attached to the diagonal of the plate. If the deformation rate exceeds the threshold, the oscillation frequency is immediately switched to a fixed value, which is determined by the ratio of the deformation rate to the thickness, until the deformation rate returns below the threshold.

[0036] Preferably, the reverse control of the cooling air flow in the final drying calibration stage includes:

[0037] The direction of the cooling air flow is set at a reverse angle to the air flow direction in the drying stage, and the reverse angle is determined by the output value of the thickness and residual stress distribution model;

[0038] During the cooling process, the surface temperature gradient data of the plate is collected in real time. If the gradient exceeds the threshold, the reverse angle is adjusted to a set ratio of the current angle, and the ratio value is calculated from the area of the gradient exceeding the standard region;

[0039] A trace amount of inert gas is mixed into the cooling air flow, and the proportion of the inert gas is dynamically adjusted by the ratio of the environmental humidity to the moisture absorption rate of the plate.

[0040] Preferably, the static equilibrium method in step 4 includes:

[0041] The static time is obtained by multiplying the ratio of the thickness to the cooling rate by the thermal expansion coefficient correction factor, and the correction factor is generated by fitting the experimental data of the material thermal expansion coefficient;

[0042] The velocity of the trace air flow during the static period is a set ratio of the maximum wind speed in the drying stage, and the ratio value is determined by the ratio of the environmental humidity to the moisture absorption rate of the plate;

[0043] If a local humidity rebound exceeding the threshold is detected during the static process, a short-term high-speed air flow circulation is triggered, and the circulation time is determined by the product relationship of the humidity exceeding the standard amplitude and the area of the rebound region.

[0044] Preferably, the multi-parameter joint logic for end point determination includes:

[0045] Four groups of humidity sensor data are collected in real time, and the standard deviation is calculated after removing the outliers that deviate from the mean by more than the set range;

[0046] The deviation between the real-time measured value of the light transmittance and the reference value needs to be less than the allowable error, and the allowable error is dynamically determined by the product relationship of the thickness and the target light transmittance;

[0047] The temperature distribution uniformity shown by the infrared thermal imaging needs to meet the standard deviation less than the threshold, and the threshold is generated by the mapping relationship between the plate thickness and the target optical performance.

[0048] Correspondingly, an embodiment of the present invention further provides a drying system for processing acrylic plates, which is used to run the drying method for processing acrylic plates according to the embodiment of the present invention, including:

[0049] Pretreatment Module:

[0050] It is configured with an ultrasonic cleaning tank, a nitrogen purging nozzle, and an anti-humidity absorption coating spraying device;

[0051] The spraying device integrates a laser interferometer. The optical path of the laser interferometer covers the surface of the sheet and is signal-connected to the control module, and is used to feedback the coating thickness deviation data in real time;

[0052] The output end of the pretreatment module is connected to the data input interface of the parameter acquisition module.

[0053] Parameter Acquisition Module:

[0054] It includes a non-contact laser thickness gauge, four groups of high-precision humidity sensors, and a spectrophotometer;

[0055] The laser thickness gauges are arranged at intervals along the sheet conveying track. After the scanning data is filtered by the filtering unit to eliminate edge distortion, it is transmitted to the control module;

[0056] The humidity sensors are respectively fixed on the brackets above, below, left, and right of the sheet in the drying oven. The sensor group is connected to the control module through a bus;

[0057] The spectrophotometer is installed on the inlet side of the drying oven. Its optical probe forms a set angle with the surface of the sheet, and the transmittance data is uploaded to the control module in real time;

[0058] Dynamic Regulation Module:

[0059] It includes a mixed gas injection unit, a partition heating unit, and a baffle driving unit;

[0060] The mixed gas injection unit consists of a nitrogen storage tank, a steam generator, and a proportional regulating valve. The control end of the proportional regulating valve receives the mixing ratio instruction issued by the control module;

[0061] The partition heating unit contains multiple independently temperature-controlled heating sub-zones. Each sub-zone is equipped with a temperature sensor and a heater. The power of the heater is dynamically adjusted by the control module according to the current humidity difference;

[0062] The baffle driving unit consists of a servo motor, an angle sensor, and a baffle array. The control signal of the servo motor is generated by the humidity difference calculation module between adjacent sub-zones, and the feedback signal of the angle sensor is transmitted to the control module in real time;

[0063] Drying Execution Module:

[0064] It includes a high-speed circulating fan, a horizontal oscillation mechanism, and a cooling system;

[0065] The rotation speed of the high-wind-speed circulation fan is controlled by the control module according to the initial humidity difference ratio, and its air outlet is communicated with the air flow channel of the deflector array;

[0066] The horizontal oscillation mechanism is mechanically connected to the deflector array through an eccentric wheel, and the rotation speed of the eccentric wheel is driven by the oscillation frequency command issued by the control module;

[0067] The cooling system includes a reverse air flow nozzle and an inert gas mixer. The nozzle angle is adjusted by a servo motor, and the gas proportion valve of the mixer is signal-connected to the control module;

[0068] Control module:

[0069] It includes a data fusion unit, a humidity gradient calculation unit and a multi-parameter determination unit;

[0070] The data fusion unit receives the thickness, humidity and light transmittance data of the preprocessing module and the parameter acquisition module, eliminates outliers and then outputs them to the humidity gradient calculation unit;

[0071] The humidity gradient calculation unit generates a target gradient curve according to the thickness and the initial humidity distribution, outputs a mixing ratio command to the dynamic regulation module, and sends a sub-region temperature setting value to the partition heating unit;

[0072] The multi-parameter determination unit receives the humidity standard deviation, light transmittance deviation and temperature uniformity data in real time. When the threshold conditions are simultaneously met, a drying termination signal is triggered, and the control module closes the heating unit and starts the cooling system;

[0073] Connection relationship between modules:

[0074] The coating thickness deviation data of the preprocessing module is transmitted to the deflector driving unit of the dynamic regulation module through the control module;

[0075] The humidity sensor group data of the parameter acquisition module is processed by the data fusion unit and then input to the humidity gradient calculation unit to generate a mixed gas ratio command;

[0076] The high-wind-speed circulation fan of the drying execution module receives the wind speed command issued by the control module, and the angle of the reverse air flow nozzle of the cooling system is triggered and adjusted by the termination signal of the multi-parameter determination unit;

[0077] The servo motor control signal of the deflector driving unit is jointly generated by the humidity gradient calculation unit and the adjacent sub-region humidity difference calculation module, and the angle feedback signal is transmitted back to the data fusion unit of the control module in real time.

[0078] The beneficial effects brought by the technical solution provided by the embodiment of the present invention at least include:

[0079] The present invention can perform personalized adjustment according to the initial state of the sheet material (such as thickness, humidity, etc.), thereby avoiding problems such as excessive humidity or uneven temperature in the traditional method. Through precise humidity gradient and temperature control, the deformation and stress concentration during the processing of acrylic sheets can be effectively reduced, improving the optical performance and physical stability of the final product. At the same time, the multi-sensor configuration and data fusion method of the system greatly improve the accuracy and controllability of the drying process, avoid possible quality problems, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0081] Figure 1 It is a flowchart of the steps of a drying method for processing acrylic sheets provided by an embodiment of the present invention;

[0082] Figure 2 It is a flowchart of the steps of step 1 of a drying method for processing acrylic sheets provided by an embodiment of the present invention;

[0083] Figure 3 It is a structural block diagram of a drying system for processing acrylic sheets provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0084] The following will describe the technical solutions in the present invention in conjunction with the drawings. At the same time, it should be noted here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments. For some well-known technologies, those skilled in the art can also adopt other alternative methods for implementation; and the drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0085] It should be pointed out that in the specification, "an embodiment", "embodiments", "exemplary embodiments", "some embodiments", etc. indicate that the described embodiments may include specific features, structures or characteristics, but not necessarily every embodiment includes the specific feature, structure or characteristic. In addition, when combining embodiments to describe specific features, structures or characteristics, implementing such features, structures or characteristics in combination with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the relevant art.

[0086] Such as Figures 1 to 3As shown, an embodiment of the present invention provides a drying method for acrylic plate processing. In step 1, first, the surface of the acrylic plate is cleaned by ultrasonic cleaning and nitrogen purging to remove surface impurities and droplets. Then, a moisture-proof coating is sprayed to ensure that the surface of the plate has a moisture-proof function. At the same time, a laser thickness gauge and a humidity sensor are used to monitor the plate in real time, and the initial thickness, humidity distribution, and light transmittance reference value of the plate are collected.

[0087] These collected data will be transmitted to the control system to provide basic data support for subsequent humidity and temperature regulation, and ensure that each acrylic plate has consistent initial parameters before processing, avoiding product quality problems caused by uneven processing.

[0088] In step 2, according to the thickness and initial humidity distribution of the plate, the system will divide the drying area into multiple sub-areas and generate a humidity gradient target value from the edge to the center of the plate. The humidity and temperature of each sub-area will be adjusted through an independently controlled mixed gas injection and temperature control system. The ratio of the mixed gas is dynamically adjusted according to the difference between the current humidity and the target humidity of the plate to ensure that the humidity changes evenly and meets the set target value.

[0089] The dynamic regulation of the humidity gradient ensures that the plate will not be locally over-wet or over-dry during the drying process, avoiding internal stress and deformation caused by uneven humidity distribution. The fine regulation of this process can improve the uniformity and optical properties of the plate.

[0090] In step 3, this step is divided into three stages: rapid dehumidification, homogenization humidity control, and final drying calibration. In the rapid dehumidification stage, the moisture on the surface of the plate is quickly removed by high-speed airflow; in the homogenization humidity control stage, the system controls the temperature and humidity within a stable range to ensure that the humidity of the plate is gradually balanced; finally, in the final drying calibration stage, the residual internal stress is eliminated through the cooling system and reverse airflow adjustment to ensure the stable form and uniform temperature of the plate.

[0091] Through humidity control and temperature adjustment in different stages, stress concentration and deformation caused by too fast or uneven changes in temperature and humidity are effectively avoided. This staged control method not only ensures the physical stability of the plate but also improves the light transmittance and optical quality of the product.

[0092] In step 4, after the drying process is completed, the plate needs to be left to stand until the ambient temperature is balanced, and the humidity rebound is inhibited through the circulation of a small amount of airflow. This stage ensures that the plate can be stable for a period of time after reaching the target temperature and humidity, avoiding the re-absorption or change of humidity due to changes in the external environment.

[0093] This step prevents the humidity rebound caused by environmental changes after the drying process by further stabilizing the humidity of the board, enabling the board to maintain its excellent performance and stability during long-term use.

[0094] Through this series of steps and precise parameter control, it is possible to ensure that every link in the processing of acrylic boards is fully optimized, thereby effectively improving the stability, efficiency of production, and the quality of the final product.

[0095] In a possible implementation, a combination of ultrasonic cleaning and nitrogen purging is used to thoroughly clean the surface of the acrylic board. Ultrasonic cleaning can effectively remove the tiny impurities, oil stains, and moisture adhering to the surface of the board, while nitrogen purging can quickly remove the remaining droplets on the surface. The cleaning time is dynamically determined according to the thickness of the board, which means that thicker boards require longer cleaning times to ensure that the cleanliness meets the requirements.

[0096] By using ultrasonic waves in conjunction with nitrogen purging, it is possible to ensure that the surface of the acrylic board reaches a highly clean state before drying, thereby reducing quality problems caused by surface impurities during the drying process.

[0097] Use a laser interferometer to scan the surface of the moisture-proof coating in real time to detect the uniformity of the coating thickness. If a local thickness deviation exceeds the preset threshold during the scanning process, the system will generate a correction path offset, and this offset is calculated based on the area and position coordinates of the deviation area. Based on this data, the control system will adjust the distribution of the coating or reapply the coating.

[0098] This precise scanning and correction mechanism ensures the uniformity of the moisture-proof coating, avoiding situations such as inaccurate humidity control or inconsistent moisture absorption performance on the board surface caused by uneven coating, and further enhancing the stability of the drying process.

[0099] Arrange four groups of high-precision humidity sensors inside the drying oven, respectively above, below, left, and right of the board, fixed at a set distance. These sensors can collect the initial humidity distribution data of each area of the board in real time. Then, the system will calculate the standard deviation based on the humidity data to understand whether the humidity distribution is uniform.

[0100] By accurately monitoring the humidity at different positions of the board, it is possible to obtain the humidity distribution status of the board before drying, providing basic data support for subsequent humidity regulation, and avoiding quality problems caused by uneven humidity.

[0101] Use a non-contact laser thickness gauge to scan along the length of the plate to measure the thickness of the plate. The scanning interval is dynamically determined based on the ratio of the area to the thickness of the plate to ensure that sufficiently dense thickness data can be obtained on large-area plates. When scanning, the system will remove the distorted data at the edge to ensure the accuracy of the thickness data and calculate the average thickness value of the entire plate.

[0102] Through high-precision laser thickness measurement technology, the thickness data of the plate can be obtained in real time, and inaccurate edge data can be eliminated to ensure that the thickness value of each plate can accurately reflect its actual situation. This provides data support for the temperature and humidity adjustment caused by thickness differences in the subsequent drying process.

[0103] Use a spectrophotometer to measure the initial transmittance of the acrylic sheet under a standard light source. During measurement, the angle between the sheet surface and the light source must be kept within the preset range. The baseline value error of the transmittance is dynamically adjusted according to the target optical performance standard to ensure that the measured transmittance meets the requirements.

[0104] By accurately measuring the initial light transmittance and setting a reasonable allowable error range, we can ensure that the optical performance of the board meets the design standards. This test provides a reference for maintaining the consistency of light transmittance during the subsequent drying process.

[0105] In one possible implementation, first, the system measures the initial humidity distribution. If its standard deviation exceeds a preset threshold, it indicates that the humidity distribution is uneven. In order to optimize the humidity gradient during the drying process, the system sets a target humidity value for the edge area of ​​the board. Specifically, the humidity target value of the edge area is set to a certain ratio of the humidity in the center area. This ratio is dynamically determined by the experimental fitting curve of thickness and moisture absorption rate of the board. Through these data, the humidity distribution characteristics of different thickness areas can be inferred to achieve reasonable humidity control.

[0106] By setting the relative ratio of the edge area humidity target value to the center area humidity, the humidity distribution of the board can be effectively adjusted to avoid humidity concentration in a certain area, resulting in unstable board quality. This humidity gradient control is particularly important for drying large-area boards, which can ensure uniform drying and reduce deformation and defects.

[0107] During the drying process, the system uses a mixture of dry nitrogen and controllable steam as the main drying medium. The ratio of the mixed gas is dynamically adjusted according to the difference between the current humidity and the target humidity. Specifically, when the difference is large, the system will increase the proportion of nitrogen because nitrogen has a stronger drying effect; when the difference is small, the proportion of controllable steam will increase, and the wetting effect of steam can effectively adjust the humidity.

[0108] By monitoring the humidity difference in real time and adjusting the gas ratio, the system can precisely control the humidity in the drying environment, avoiding over-drying or insufficient humidity. This flexible adjustment of the gas ratio ensures the stability of the drying process and reduces the quality fluctuations of the boards caused by unstable environments.

[0109] For different sub-regions of the board (such as the central region and the edge region), the temperature set value is calculated based on the difference between the target humidity and the current humidity. The specific calculation formula is: the difference between the target humidity and the current humidity multiplied by the thickness correction coefficient. This correction coefficient is generated from the mapping relationship between the humidity difference and the board deformation amount in historical production data. Based on the accumulation of historical data, the correction coefficient can reflect the response characteristics of different thickness regions to temperature and humidity differences during the drying process.

[0110] By dynamically calculating the temperature set value and applying the thickness correction coefficient, precise temperature control can be achieved for different thickness regions. This adjustment can effectively control the deformation problem of the board and avoid quality problems such as warping and cracking in the regions with larger or smaller thicknesses due to too high or too low temperatures during the drying process.

[0111] In a possible implementation, the staged stress collaborative drying in step 3 is dynamically adjusted according to multiple variable factors such as different humidity, temperature, and thickness through a refined drying control mode, minimizing the stress concentration and deformation of the board during the drying process.

[0112] Specifically, in the rapid dehumidification stage, the system starts a high wind speed circulation mode. The setting of the air flow speed is controlled by the ratio of the difference between the initial humidity and the target humidity. The larger the difference, the more obvious the humidity difference, and the system will increase the wind speed to quickly remove the surface moisture; conversely, when the humidity difference is small, the wind speed is reduced to avoid over-drying. During this process, the temperature gradually rises in a stepped manner. The temperature rise amplitude in each stage is determined by the product of the current humidity gradient and the reciprocal of the board thickness. The humidity gradient is calculated by the ratio of the humidity difference between adjacent sub-regions and the distance, ensuring that the humidity differences in different thicknesses and regions are effectively eliminated.

[0113] By adjusting the wind speed and the temperature rise amplitude, the discharge of moisture and the evaporation rate of the surface moisture of the board can be precisely controlled, avoiding local over-drying or uneven humidity, and preventing the occurrence of board deformation or cracks. The focus of this stage is on rapid and uniform humidity reduction, laying a foundation for the subsequent homogeneous humidity control stage.

[0114] When the overall humidity of the board decreases to a preset critical value, the system will automatically switch to the low-wind-speed constant-temperature mode. In this mode, the air flow speed is low to avoid unnecessary stress on the board surface caused by excessive air flow. The deflector plate switches to the horizontal oscillation mode, and the oscillation frequency increases linearly according to the humidity decrease rate. The frequency increase is related to the product relationship of the humidity decrease rate and the thickness. That is, when the humidity decrease rate is faster, the frequency increase is larger to ensure uniform distribution of moisture and avoid uneven stress.

[0115] By combining the low-wind-speed and oscillation modes, it is possible to uniformly adjust the humidity distribution under constant temperature, especially for areas with uneven thickness, maintain the balance of humidity and temperature, and reduce deformation or cracks caused by humidity differences.

[0116] In the final stage of drying, the system will turn off the heating element and start the cooling system for cooling. The adjustment of the cooling air speed is inversely proportional to the thickness of the board. The larger the thickness, the lower the cooling air speed. The direction of the cooling air flow is set at a reverse angle to the air flow direction in the drying stage. The size of this reverse angle is output by the residual stress distribution model, which is constructed through the mapping relationship between thickness and stress concentration areas in historical production data.

[0117] Through the reverse angle setting and thickness-related cooling air speed control, it is possible to effectively eliminate residual stress and avoid warping or deformation of the board during the cooling process. This cooling process combines the analysis of the board thickness and historical stress distribution, making the cooling process more accurate and further improving the final quality of the board.

[0118] This staged stress collaborative drying method can significantly improve the quality of acrylic boards, reduce problems such as deformation and cracks, and achieve an efficient and high-quality production process through meticulous process control and dynamic adjustment.

[0119] In a possible implementation, the method for suppressing local overheating in the rapid dehumidification stage prevents local overheating through precise temperature control and dynamic adjustment, ensures uniform temperature distribution during the drying process, and avoids overheating phenomena.

[0120] Specifically, first, the surface temperature distribution of the acrylic board is monitored in real time through an infrared thermal imager. The system will detect the area of sudden temperature change, that is, the continuous area where the temperature change rate exceeds the set threshold. This process ensures that the area of abnormal temperature change can be quickly discovered and the occurrence of overheating areas can be avoided. The infrared thermal imager can monitor the temperature changes at different positions on the board surface with high precision, provide temperature data in real time, and provide a basis for subsequent control measures.

[0121] This monitoring process can efficiently and accurately capture abnormal local temperature changes, prevent overheating problems caused by improper temperature control, and avoid damage to the board caused by excessive temperature concentration.

[0122] Furthermore, once a mutation region is detected, the system will immediately reduce the heating power of that region to a set percentage of the initial value and simultaneously trigger local air flow acceleration. Specifically, the air flow acceleration time is a function of the area of the mutation region, and the larger the area, the longer the air flow acceleration time. Air flow acceleration can accelerate the heat dissipation in the local area, rapidly reduce the temperature, and thus prevent the impact of local overheating on the plate.

[0123] By reducing the heating power and accelerating the air flow, the local temperature can be quickly stabilized, reducing the thermal stress caused by too rapid temperature rise and avoiding phenomena such as local deformation, cracks, or uneven drying. This control strategy effectively suppresses the risk of local overheating while maintaining the drying uniformity of the entire plate.

[0124] After the problem of local overheating is effectively suppressed, after the air flow acceleration ends, the system will gradually restore the heating rate to a set percentage of the original calculated value. This restoration ratio is determined by the product of the duration and the area of the mutation region, that is, the longer the duration and the larger the area of the mutation region, the smaller the restoration ratio, ensuring that no new overheating problems will be caused due to too rapid restoration.

[0125] This control of the restoration ratio based on duration and area can smoothly restore the temperature to the predetermined level, avoiding excessive stress concentration or plate deformation caused by sudden temperature rise after overheating.

[0126] If the same sub-region triggers two overheating suppression operations continuously within a short period of time, the system will automatically lock the temperature of that sub-region and trigger an alarm. At this time, the relevant operators can timely detect and adjust the equipment parameters or processes to avoid overheating problems in that region again.

[0127] Through the alarm mechanism, it can timely alert the operators to pay attention to abnormal situations and make adjustments to prevent the appearance of overheated regions from affecting the overall drying effect. The locking mechanism ensures that this region will not be heated continuously in a short period of time, thus effectively avoiding mistakes in temperature control.

[0128] Through precise temperature monitoring and dynamic control, the local overheating suppression method effectively guarantees the temperature uniformity of the acrylic plate during the drying process, improves the quality and production efficiency of the plate, reduces losses caused by overheating, and enhances the reliability and safety of the overall production process.

[0129] In a possible implementation, the oscillation frequency control logic in the homogenization and humidity control stage controls the humidity drop rate and deformation of the plate by dynamically adjusting the oscillation frequency to ensure the uniformity during the drying process and the quality of the plate.

[0130] Specifically, the initial value of the oscillation frequency is determined by the product relationship between the thickness of the board and the current humidity decrease rate. Specifically, the greater the thickness of the board and the faster the humidity decrease rate, the initial oscillation frequency should be appropriately reduced; conversely, when the board is thinner and the humidity decrease rate is slower, the oscillation frequency should be appropriately increased.

[0131] By considering the relationship between the board thickness and the humidity decrease rate, the system can set an initial reasonable oscillation frequency for each batch of production processes. This can adjust the oscillation frequency according to different board characteristics, ensure the uniformity during the drying process, and avoid uneven or excessive humidity decrease caused by inappropriate frequencies, thereby ensuring the quality of the final product.

[0132] During the entire drying process, the system monitors the humidity decrease rate in real time. If the humidity decrease rate shows an increasing trend, the oscillation frequency will increase according to the linear ratio of the humidity change amplitude. Specifically, when the humidity decreases rapidly, increasing the oscillation frequency can enhance air flow, improve the moisture evaporation efficiency, and thus accelerate the drying process.

[0133] This mechanism of dynamically adjusting the oscillation frequency can effectively avoid problems such as surface cracking or uneven drying of the board caused by too fast a humidity decrease rate. At the same time, increasing the oscillation frequency can increase the contact frequency between the air and the board surface, thereby accelerating the discharge of moisture and improving the drying efficiency.

[0134] Through the strain gauge array attached to the diagonal of the board, the system monitors the board's deformation rate in real time. If the deformation rate exceeds the set threshold, the system will immediately switch the oscillation frequency to a fixed value. This fixed value is determined by the ratio of the deformation rate to the board thickness. The system will not resume the dynamic adjustment of the oscillation frequency until the deformation rate returns below the threshold.

[0135] When the deformation rate exceeds the threshold, it means that the board may have stress concentration due to uneven drying, resulting in deformation or cracking. By switching the oscillation frequency to a fixed value, it is possible to reduce the sharp changes in temperature and humidity during the drying process, thereby avoiding further deformation and ensuring the structural stability of the board.

[0136] When the deformation rate returns below the threshold, the oscillation frequency will resume the dynamic adjustment mode according to factors such as the humidity decrease rate and the board thickness. This adjustment ensures that after the deformation problem is suppressed, the system can resume the normal drying rhythm and continue to control the humidity.

[0137] This recovery mechanism ensures that when the board deforms, the drying process can be slowed down in a timely manner to avoid the spread of deformation, and when the deformation problem is solved, the oscillation frequency resumes normal adjustment, effectively maintaining the continuity and efficiency of the drying process.

[0138] The oscillation frequency control logic effectively controls the rate of humidity decline and the risk of sheet deformation through precise dynamic adjustment and real-time response, optimizes the drying process of acrylic sheets, improves production efficiency and product quality, and ensures uniform drying and morphological stability of the sheets.

[0139] In a possible implementation, the cooling air flow reverse control mechanism in the final drying calibration stage ensures temperature uniformity and sheet deformation suppression during the cooling process by dynamically adjusting the air flow direction, angle, and gas composition.

[0140] Specifically, in the cooling stage, the direction of the cooling air flow is set at a reverse angle to the air flow direction in the drying stage. This reverse angle is determined by the output value of the sheet thickness and residual stress distribution model. The residual stress distribution model calculates the stress concentration areas that may cause deformation by analyzing the temperature and humidity changes of the sheet during the drying process, thereby setting an appropriate reverse air flow angle to avoid sheet deformation caused by uneven temperature.

[0141] By setting the reverse angle according to the output value of the residual stress distribution model, it can be ensured that the air flow during the cooling process can effectively counteract the internal stress formed in the sheet during the drying process, reducing the risk of sheet deformation caused by excessive temperature gradient. This dynamic adjustment of the air flow reverse control helps to improve the uniformity of the cooling process and ensure the stability of the sheet during the cooling process.

[0142] During the cooling process, the system real-time collects the temperature gradient data on the sheet surface. If it is found that the temperature gradient exceeds the set threshold, the system will adjust the reverse angle of the cooling air flow according to the area of the gradient exceeding the standard area. The adjustment ratio is calculated by the area of the gradient exceeding the standard area, that is, if the temperature non-uniform area is larger, the reverse angle adjustment ratio will be larger, so as to better balance the temperature distribution during the cooling process.

[0143] By real-time monitoring the temperature gradient and adjusting the reverse angle according to the area of the exceeding standard area, the system can precisely control the distribution of the cooling air flow, avoiding stress concentration and deformation caused by excessive local cooling. This step ensures the uniformity of the sheet surface temperature distribution during the cooling process and reduces problems such as warping and cracking of the sheet caused by uneven cooling.

[0144] A trace amount of inert gas, such as nitrogen or argon, is mixed into the cooling air flow to reduce the humidity of the air flow and improve the control accuracy of the cooling process. The ratio of the inert gas is dynamically adjusted by the ratio of the ambient humidity and the moisture absorption rate of the sheet. If the ambient humidity is high, the system will increase the ratio of the inert gas, thereby reducing the condensation of water vapor and improving the cooling efficiency; if the ambient humidity is low, the ratio of the inert gas will be reduced accordingly.

[0145] The introduction of inert gas can reduce the humidity fluctuation of air during the cooling process, avoid the condensation of water vapor on the surface of the sheet caused by excessive humidity, and thus reduce the impact of surface moisture on the sheet. The proportion of inert gas is dynamically adjusted according to the environmental humidity and the moisture absorption rate, enabling the cooling process to adapt to the external environment in real time and maintaining the stability and efficiency of the cooling process.

[0146] The reverse control of the cooling air flow ensures temperature uniformity, humidity control accuracy, and suppression of sheet deformation during the cooling process through multi-level adjustment measures, effectively improving the quality and production efficiency of the acrylic sheet.

[0147] In a possible implementation, the static equilibrium method in step 4 aims to optimize the drying process by controlling the static time, the velocity of the micro air flow, and the short-time high-speed air flow circulation, ensuring uniform drying of the acrylic sheet and reducing deformation caused by uneven humidity.

[0148] Specifically, the static equilibrium method in step 4 aims to optimize the drying process by controlling the static time, the velocity of the micro air flow, and the short-time high-speed air flow circulation, ensuring uniform drying of the acrylic sheet and reducing deformation caused by uneven humidity. Among them, the thermal expansion coefficient correction factor is generated by fitting the experimental data of the material's thermal expansion coefficient. According to the experimental data, the thermal expansion coefficient of the material affects the dimensional change of the material during temperature change, and thus affects the static time. Thicker sheets or slower cooling rates require longer static times to ensure that the temperature of the sheet reaches equilibrium and to avoid stress generation during the cooling process.

[0149] By calculating the static time based on the ratio of thickness to cooling rate, the duration of the static process can be controlled more precisely. For sheets with different thicknesses and cooling rates, appropriate static times ensure that the acrylic sheet can cool evenly, effectively reducing thermal stress and deformation and ensuring the quality of the processed sheet.

[0150] During the static period, the velocity of the micro air flow is set as a proportion of the maximum wind speed in the drying stage. The proportion value is determined by the ratio of the environmental humidity to the moisture absorption rate of the sheet. If the environmental humidity is high or the moisture absorption rate of the sheet is fast, the proportion of the micro air flow will be adjusted accordingly to reduce the air flow velocity, so as to avoid excessive surface drying caused by rapid air flow, resulting in too large a temperature difference between the inside and the outside and increasing the risk of deformation.

[0151] By adjusting the velocity of the micro air flow, the air flow during the static period can be controlled, reducing the humidity difference between the surface and the inside caused by excessive drying. Appropriate air flow velocity can promote the uniform evaporation of surface moisture without accelerating the drying process excessively, thus ensuring the temperature and humidity balance of the sheet and avoiding warping or cracking caused by uneven drying.

[0152] During the static process, if it is detected that the local humidity rebounds and exceeds the preset threshold, the system will trigger a short-term high-speed air flow circulation. The duration of this circulation is determined by the product relationship between the humidity exceeding standard amplitude and the area of the humidity rebound area. Specifically, areas with more severe humidity rebound and larger areas will activate a longer-duration high-speed air flow circulation to quickly remove the moisture in that area and avoid uneven local drying caused by moisture accumulation.

[0153] By triggering a short-term high-speed air flow circulation, the local humidity rebound can be effectively controlled to avoid its impact on the surface of the board. After the area with excessive humidity is processed by the short-term high-speed air flow, the uniformity of temperature and humidity can be restored, thus ensuring the overall stability of the board during the static period. This process helps to maintain the quality of the board and avoid deformation or uneven drying caused by humidity rebound.

[0154] In a possible implementation, the multi-parameter joint logic for end point determination comprehensively judges whether the drying process reaches the end standard by combining humidity sensor data, light transmittance measurement values, and infrared thermal imaging temperature distribution. The collaborative work of these parameters ensures that the quality and performance of the acrylic board meet the expected requirements during the drying process.

[0155] Specifically, data from four groups of humidity sensors are collected in real time. After excluding outliers that deviate from the mean by more than the set range, the standard deviation is calculated. The humidity sensors are used to monitor the humidity changes on the surface of the acrylic board. Excluding outliers can ensure the accuracy of the data and avoid misjudgment caused by occasional interference or sensor failure.

[0156] The collection of humidity sensor data and the calculation of the standard deviation help to monitor the drying situation of the board in real time. The smaller the standard deviation, the more uniform the humidity change and the more stable the drying process. If the standard deviation is large, it indicates that there is uneven local humidity on the board, which may mean that the drying is not yet complete and further drying is required.

[0157] The light transmittance of the acrylic board is measured in real time and compared with the set reference value. The allowable error range is dynamically determined by the product relationship between the thickness of the board and the target light transmittance. The light transmittance reflects the optical performance of the acrylic board. An appropriate light transmittance means that the drying degree is appropriate.

[0158] As a key indicator of optical performance, the light transmittance directly affects the use effect of the board. By dynamically adjusting the allowable error value and determining the accuracy of end point determination according to the thickness of the board and the target light transmittance, it can ensure that the transparency and optical performance of the board remain in an ideal state during the drying process and avoid the light transmittance not meeting the requirements due to over-drying or under-drying.

[0159] Use infrared thermal imaging technology to monitor the temperature distribution of the acrylic board in real time, and require that the standard deviation of the temperature distribution is less than the set threshold. This threshold is generated from the mapping relationship between the thickness of the board and the target optical performance. Through infrared imaging, it is possible to quickly determine whether there are areas of local overheating or unheated areas on the board.

[0160] Temperature uniformity is a crucial factor during the drying process. Non-uniform temperature may cause different drying degrees on the surface and inside of the board, resulting in deformation or uneven stress. By controlling the standard deviation not to exceed the set threshold, it can ensure that the temperature of each part of the board is balanced during the drying process, and finally obtain a good drying effect.

[0161] By monitoring humidity, light transmittance, and temperature distribution in real time, and combining the joint logical determination of multiple parameters, this method can more accurately control the drying process, ensuring high-quality drying of the acrylic board during processing. This not only improves production efficiency but also guarantees the optical performance and uniformity of the product.

[0162] Correspondingly, an embodiment of the present invention also provides a drying system for processing acrylic boards, which is used to run a drying method for processing acrylic boards according to an embodiment of the present invention, including:

[0163] Pretreatment module:

[0164] Equipped with an ultrasonic cleaning tank, a nitrogen purging nozzle, and an anti-moisture coating spraying device;

[0165] The spraying device integrates a laser interferometer. The optical path of the laser interferometer covers the surface of the board and is signal-connected to the control module, and is used to feedback the coating thickness deviation data in real time;

[0166] The output end of the pretreatment module is connected to the data input interface of the parameter acquisition module.

[0167] Parameter acquisition module:

[0168] Includes a non-contact laser thickness gauge, four groups of high-precision humidity sensors, and a spectrophotometer;

[0169] The laser thickness gauges are arranged at intervals along the board conveying track, and their scanned data are transmitted to the control module after the edge distortion is removed by the filtering unit;

[0170] The humidity sensors are respectively fixed on the brackets above, below, left, and right of the board in the drying box. The sensor group is connected to the control module through a bus;

[0171] The spectrophotometer is installed on the inlet side of the drying box, and its optical probe forms a set angle with the surface of the board, and the light transmittance data is uploaded to the control module in real time;

[0172] Dynamic regulation module:

[0173] It includes a mixed gas injection unit, a partition heating unit and a deflector drive unit;

[0174] The mixed gas injection unit consists of a nitrogen storage tank, a steam generator and a proportional regulating valve. The control end of the proportional regulating valve receives the mixing ratio instruction issued by the control module;

[0175] The partition heating unit includes multiple heating sub - zones with independent temperature control. Each sub - zone is equipped with a temperature sensor and a heater, and the power of the heater is dynamically adjusted by the control module according to the current humidity difference;

[0176] The deflector drive unit consists of a servo motor, an angle sensor and a deflector array. The control signal of the servo motor is generated by the humidity difference calculation module between adjacent sub - zones, and the feedback signal of the angle sensor is transmitted to the control module in real time;

[0177] Drying execution module:

[0178] It includes a high - speed circulation fan, a horizontal oscillation mechanism and a cooling system;

[0179] The rotation speed of the high - speed circulation fan is proportionally controlled by the control module according to the initial humidity difference value, and its air outlet is connected to the air flow channel of the deflector array;

[0180] The horizontal oscillation mechanism is mechanically connected to the deflector array through an eccentric wheel, and the rotation speed of the eccentric wheel is driven by the oscillation frequency instruction issued by the control module;

[0181] The cooling system includes a reverse air flow nozzle and an inert gas mixer. The nozzle angle is adjusted by the servo motor, and the gas proportional valve of the mixer is signal - connected to the control module;

[0182] Control module:

[0183] It includes a data fusion unit, a humidity gradient calculation unit and a multi - parameter determination unit;

[0184] The data fusion unit receives the thickness, humidity and light transmittance data from the pre - processing module and the parameter acquisition module, eliminates the outliers and then outputs them to the humidity gradient calculation unit;

[0185] The humidity gradient calculation unit generates a target gradient curve according to the thickness and the initial humidity distribution, outputs a mixing ratio instruction to the dynamic regulation module, and sends a sub - zone temperature setting value to the partition heating unit;

[0186] The multi - parameter determination unit receives the humidity standard deviation, the light transmittance deviation and the temperature uniformity data in real time. When the threshold conditions are met simultaneously, it triggers a drying termination signal, and the control module turns off the heating unit and starts the cooling system;

[0187] Inter-module connection relationship:

[0188] The coating thickness deviation data of the pretreatment module is transmitted to the deflector drive unit of the dynamic regulation module through the control module;

[0189] The data of the humidity sensor group of the parameter acquisition module is processed by the data fusion unit and then input to the humidity gradient calculation unit to generate a mixed gas ratio instruction;

[0190] The high-speed circulating fan of the drying execution module receives the wind speed instruction issued by the control module, and the angle of the reverse air flow nozzle of the cooling system is triggered and adjusted by the termination signal of the multi-parameter determination unit;

[0191] The servo motor control signal of the deflector drive unit is jointly generated by the humidity gradient calculation unit and the adjacent sub-region humidity difference calculation module, and the angle feedback signal is transmitted back to the data fusion unit of the control module in real time.

[0192] The present invention covers any substitutions, modifications, equivalent methods and solutions made on the essence and scope of the present invention. In order to enable the public to have a thorough understanding of the present invention, specific details are described in detail in the preferred embodiments of the present invention, and those skilled in the art can fully understand the present invention without these detailed descriptions. In addition, well-known methods, processes, procedures, components and circuits are not described in detail to avoid unnecessary confusion to the essence of the present invention.

[0193] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A drying system for acrylic sheet processing, characterized in that, Including: Pretreatment module: Equipped with an ultrasonic cleaning tank, a nitrogen purging nozzle, and an anti-humidity-absorbing coating spraying device; The spraying device integrates a laser interferometer. The optical path of the laser interferometer covers the surface of the sheet and is signal-connected to the control module, and is used to feedback the coating thickness deviation data in real time; The output end of the pretreatment module is connected to the data input interface of the parameter acquisition module; Parameter acquisition module: Including a non-contact laser thickness gauge, four groups of high-precision humidity sensors, and a spectrophotometer; The laser thickness gauges are arranged at intervals along the sheet conveying track. After the scanned data is filtered by the filtering unit to eliminate edge distortion, it is transmitted to the control module; The humidity sensors are respectively fixed on the brackets above, below, left, and right of the sheet in the drying oven. The sensor group is connected to the control module through a bus; The spectrophotometer is installed on the inlet side of the drying oven. Its optical probe forms a set angle with the surface of the sheet, and the transmittance data is uploaded to the control module in real time; Dynamic regulation module: Including a mixed gas injection unit, a partition heating unit, and a baffle plate driving unit; The mixed gas injection unit consists of a nitrogen storage tank, a steam generator, and a proportional regulating valve. The control end of the proportional regulating valve receives the mixing ratio instruction issued by the control module; The partition heating unit contains multiple heating sub-zones with independent temperature control. Each sub-zone is equipped with a temperature sensor and a heater; The baffle plate driving unit consists of a servo motor, an angle sensor, and a baffle plate array. The control signal of the servo motor is generated by the humidity difference calculation module between adjacent sub-zones, and the feedback signal of the angle sensor is transmitted to the control module in real time; Drying execution module: Including a high-speed circulating fan, a horizontal oscillation mechanism, and a cooling system. The air outlet of the high-speed circulating fan is communicated with the air flow channel of the baffle plate array; The horizontal oscillation mechanism is mechanically connected to the baffle plate array through an eccentric wheel. The rotation speed of the eccentric wheel is driven by the oscillation frequency instruction issued by the control module; The cooling system includes a reverse air flow nozzle and an inert gas mixer. The nozzle angle is adjusted by a servo motor, and the gas proportional valve of the mixer is signal-connected to the control module; Control module: Including a data fusion unit, a humidity gradient calculation unit, and a multi-parameter determination unit; The data fusion unit receives the thickness, humidity, and transmittance data of the pretreatment module and the parameter acquisition module, eliminates the outliers, and then outputs them to the humidity gradient calculation unit; The humidity gradient calculation unit generates a target gradient curve according to the thickness and the initial humidity distribution, outputs a mixing ratio instruction to the dynamic regulation module, and sends a sub-zone temperature setting value to the partition heating unit; The multi-parameter determination unit receives the humidity standard deviation, transmittance deviation, and temperature uniformity data in real time. When the threshold conditions are met simultaneously, it triggers a drying termination signal, and the control module turns off the heating unit and starts the cooling system; Connection relationship between modules: The coating thickness deviation data of the pretreatment module is transmitted to the baffle plate driving unit of the dynamic regulation module through the control module; The humidity sensor group data of the parameter acquisition module is processed by the data fusion unit of the control module and then input to the humidity gradient calculation unit to generate a mixed gas ratio instruction; The high-speed circulation fan of the drying execution module receives the wind speed command issued by the control module, and the reverse airflow nozzle angle of the cooling system is adjusted by the termination signal of the multi-parameter determination unit; The servo motor control signal of the guide plate driving unit is jointly generated by the humidity gradient calculation unit of the control module and the adjacent sub-area humidity difference calculation module, and the angle feedback signal is transmitted back to the data fusion unit of the control module in real time.

2. A drying method for processing acrylic plates, which is implemented by using the drying system for processing acrylic plates described in claim 1, and is characterized in that, The following steps are involved: Step 1: Pretreatment and parameter collection: Clean the surface of the high-precision optical acrylic plate and spray an anti-hygroscopic coating, and simultaneously collect the plate thickness, initial humidity distribution and transmittance benchmark value; Step 2: Dynamic zoning and humidity-temperature coordinated control: According to the thickness and initial humidity distribution data, the drying area is divided into multiple independent sub-areas, and a humidity gradient target value decreasing from the edge to the center is generated. Dynamic humidity regulation is achieved by injecting mixed gas and independent temperature control of the sub-areas; Step 3: Stress-coordinated drying in stages: Rapid dehumidification, homogenization humidity control and final drying calibration are performed in sequence. Internal stress is eliminated through gradient heating, dynamic orientation of guide plates and cooling reverse airflow. The endpoint judgment must simultaneously meet the humidity standard deviation, transmittance deviation and temperature uniformity thresholds. The staged stress coordinated drying comprises: Rapid dehumidification stage: start the high wind speed circulation mode, the air flow speed is controlled by the difference ratio between the initial humidity and the target humidity, the greater the difference, the higher the wind speed; the temperature rises in steps, and the temperature rise amplitude in each stage is determined by the inverse product of the current humidity gradient and the thickness, and the humidity gradient is calculated by the ratio of the humidity difference between adjacent sub-areas to the distance; Homogenization and humidity control stage: When the overall humidity of the board drops to the preset critical value, it switches to low wind speed constant temperature mode, and the guide plate switches to horizontal oscillation mode. The oscillation frequency increases linearly with the rate of humidity decrease, and the frequency increase is determined by the product of the rate change amplitude and the thickness; Final drying calibration stage: turn off the heating element and turn on the cooling system. The cooling wind speed is adjusted in proportion to the thickness. The greater the thickness, the lower the wind speed. The cooling airflow direction is set at an angle opposite to the airflow direction in the drying stage. The reverse angle is determined by the output value of the residual stress distribution model. The model is constructed by the mapping relationship between thickness and historical stress concentration area. Step 4: Post-processing balance: Let the board stand until the ambient temperature is balanced, and maintain a small amount of air circulation to suppress humidity rebound.

3. A drying method for processing acrylic plates according to claim 2, characterized in that, The specific operations of step 1 include: Ultrasonic cleaning and nitrogen purging were used to remove surface impurities and droplets, and the cleaning time was a function of the plate thickness; The surface of the anti-hygroscopic coating is scanned in real time by a laser interferometer. If the local thickness deviation is detected to exceed the set threshold, an offset of the correction path is generated. The offset is calculated by the area and position coordinates of the deviation area. Four sets of high-precision humidity sensors are arranged in the drying box, located at set distances above, below, on the left and on the right of the board, to collect initial humidity distribution data and calculate the standard deviation; Use a non-contact laser thickness gauge to scan the thickness data at intervals along the length of the plate. The scanning interval is dynamically determined by the ratio of the plate area to the thickness. After eliminating the edge distortion data, the average thickness value is calculated. Measure the initial light transmittance under a standard light source using a spectrophotometer. When measuring, the surface of the sheet material forms a set angle with the light source, and the allowable error of the light transmittance reference value is dynamically determined by the target optical performance index.

4. A drying method for processing acrylic sheets according to claim 3, characterized in that, The generation logic of the humidity gradient target value in step 2 includes: If the standard deviation of the initial humidity distribution exceeds the set threshold, the humidity target value in the edge area is set to a set proportion of the humidity in the central area, and the proportion is dynamically determined by the experimental fitting curve of the thickness and the moisture absorption rate of the sheet material; The mixed gas is composed of dry nitrogen and controllable steam mixed in proportion. The mixing proportion is dynamically adjusted according to the difference between the current humidity and the target humidity. The greater the difference, the higher the proportion of nitrogen; The calculation formula for the set temperature value of independent heating in each sub-region is: the difference between the target humidity and the current humidity multiplied by the thickness correction factor, and the correction factor is generated from the mapping relationship between the humidity difference and the sheet material deformation amount in historical production data.

5. A drying method for processing acrylic plates according to claim 4, characterized in that, The rapid dehumidification stage has a local overheating suppression method, which specifically includes: Real-time monitor the surface temperature distribution of the sheet material through an infrared thermal imager. If a local temperature mutation area is detected, that is, a continuous area where the temperature change rate exceeds the set threshold, immediately reduce the heating power of the corresponding sub-region to a set proportion of the initial value and trigger local air flow acceleration; The local air flow acceleration time is a function of the area of the mutation area. After the acceleration time ends, the heating rate resumes to a set proportion of the original calculated value, and the proportion value is determined by the product of the duration and area of the mutation area; If the overheating suppression is continuously triggered twice in the same sub-region, lock the temperature of the sub-region and trigger an alarm.

6. A drying method for processing acrylic plates according to claim 5, characterized in that, The homogenization humidity control stage has an oscillation frequency control logic, which specifically includes: The initial value of the oscillation frequency is determined by the product relationship between the thickness of the sheet material and the current humidity decrease rate; Real-time monitor the humidity decrease rate. If the rate increases, the oscillation frequency increases linearly according to the change amplitude of the rate; Monitor the shape change rate through a strain gauge array attached to the diagonal of the sheet material. If the shape change rate exceeds the threshold, immediately switch the oscillation frequency to a fixed value, and the fixed value is determined by the ratio of the shape change rate to the thickness until the shape change rate resumes below the threshold.

7. A drying method for processing acrylic plates according to claim 4, characterized in that, In the final drying and calibration stage, it includes reverse control of the cooling air flow. The reverse control of the cooling air flow specifically includes: The direction of the cooling air flow forms a reverse set angle with the air flow direction in the drying stage, and the reverse angle is determined by the output value of the thickness and the residual stress distribution model; During the cooling process, real-time collect the surface temperature gradient data of the sheet material. If the gradient exceeds the threshold, adjust the reverse angle to a set proportion of the current angle, and the proportion value is calculated from the area of the gradient exceeding the standard area; A trace amount of inert gas is mixed into the cooling air flow, and the proportion of the inert gas is dynamically adjusted by the ratio of the ambient humidity to the moisture absorption rate of the sheet material.

8. A drying method for processing acrylic plates according to claim 2, characterized in that, In step 4, it includes: The standing time is the ratio of the thickness to the cooling rate multiplied by the thermal expansion coefficient correction factor, and the correction factor is generated by fitting the experimental data of the material thermal expansion coefficient; The speed of the trace air flow during the standing period is a set proportion of the maximum wind speed in the drying stage, and the proportion value is determined by the ratio of the ambient humidity to the moisture absorption rate of the sheet material; If a local humidity rebound exceeding the threshold is detected during the standing process, trigger a short-term high-speed air flow cycle, and the cycle time is determined by the product relationship between the humidity exceeding the standard amplitude and the area of the rebound area.

9. A drying method for processing acrylic plates according to claim 2, characterized in that, The multi-parameter combined logic for end point determination includes: Collect four groups of humidity sensor data in real time, calculate the standard deviation after removing outliers that deviate from the mean by more than the set range; The deviation between the real-time measured value of the light transmittance and the reference value needs to be less than the allowable error, and the allowable error is dynamically determined by the product relationship between the thickness and the target light transmittance; The temperature distribution uniformity shown by the infrared thermal imaging needs to meet the standard deviation less than the threshold value, and the threshold value is generated by the mapping relationship between the plate thickness and the target optical performance.

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