Synchronous temperature control method for co-extrusion molding of multi-layer polymer film

Abstract

The invention discloses a synchronous temperature control method for co-extrusion molding of a multilayer polymer film, and relates to the technical field of high polymer material processing, and the method comprises the following steps: setting a target temperature interval of each polymer layer of the multilayer polymer film, and according to the melting characteristics, heat sensitivity and interface bonding requirements of each layer of material, setting a target temperature interval of each polymer layer of the multilayer polymer film; respectively determining an extrusion temperature set value and an allowable fluctuation range; through layered independent temperature control and preheating matching, thermal behavior synchronization of multiple polymer melts is achieved, and the interface bonding stability is improved; through a die head heat insulation and buffer structure, interlayer heat interference is effectively shielded, and the integrity of a functional layer is guaranteed; through the intelligent closed-loop temperature control system, the state of each temperature control area is predicted and adjusted in real time, and self-adaptive optimization of thermal control is achieved. And the co-extrusion quality, the consistency and the production intelligent level of the multi-layer film are integrally improved.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, specifically to a synchronous temperature control method for co-extrusion molding of multilayer polymer films. Background Technology

[0002] "Synchronous temperature control for co-extrusion molding of multilayer polymer films" refers to a coordinated temperature control system used during the co-extrusion process of multilayer polymer films. This system addresses the melting characteristics and heat sensitivity of different polymer layers, dynamically and consistently regulating the temperatures of key temperature zones in the extruder, die, and cooling device. This ensures that each layer remains within its optimal processing temperature range throughout the entire process of flow, convergence, lamination, and cooling, thereby guaranteeing good interfacial bonding strength, thickness uniformity, and the physical properties and dimensional stability of the final product. This method overcomes the problems of poor interlayer thermal matching, weak welds, or interfacial defects in traditional temperature control methods and is a crucial technical means to achieve continuous and intelligent production of high-performance multilayer films.

[0003] Existing technologies have the following shortcomings: In the co-extrusion molding process of multilayer polymer films, the interfacial "thermal migration instability" caused by interlayer thermal cross-interference is an easily overlooked but highly destructive problem. Specifically, when polymer layers with different melting points flow in parallel in the die head or composite area, if the temperature control system fails to achieve precise synchronous adjustment of the temperature of each layer, the heat from the high-temperature layer may inadvertently migrate to the adjacent low-temperature layer, disrupting its original thermal equilibrium. This thermal disturbance may cause the low-temperature layer to soften prematurely or over-melt locally, thereby damaging the interlayer weld interface and producing defects such as microscopic delamination and poor adhesion. Such problems are usually difficult to detect in the early stages of molding, but they can easily induce breakage, delamination, or heat-sealing failure during subsequent processing or use, seriously affecting product performance and reliability.

[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a synchronous temperature control method for co-extrusion molding of multilayer polymer films. By independently controlling the temperature of each layer and matching preheating, the thermal behavior of the multi-polymer melt is synchronized, improving interfacial bonding stability. Through die insulation and buffering structures, interlayer thermal interference is effectively shielded, ensuring the integrity of functional layers. An intelligent closed-loop temperature control system predicts and adjusts the state of each temperature control zone in real time, achieving adaptive optimization of thermal control. Overall, this method improves the quality, consistency, and intelligent production level of multilayer film co-extrusion, thus solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a synchronous temperature control method for co-extrusion molding of multilayer polymer films, comprising the following steps: Set the target temperature range for each polymer layer of the multilayer polymer film, and determine the extrusion temperature setting and allowable fluctuation range according to the melting characteristics, thermal sensitivity and interfacial adhesion requirements of each layer material. Before each layer of polymer melt enters an independent screw extruder, the raw material particles are preheated to bring the raw material temperature close to their respective target melting temperature, thereby reducing the impact of temperature rise differences during extrusion on interfacial thermal stability. The temperature of each extrusion channel is independently controlled by multiple precision temperature control units, including the screw barrel heating zone, melt conveying channel and each layer of die outlet. Thermocouple data is collected in real time to provide feedback and adjust the output power, ensuring that each layer of melt reaches the set temperature and remains stable before the co-extrusion point. A heat-insulating and pressure-isolieving channel structure is set in the flow convergence area of ​​the die head to physically isolate the thermal intrusion of the high-temperature melt into the low-temperature layer. A thermal barrier is designed using a thermal conductivity gradient material to limit the rate of lateral heat transfer between layers. Immediately after the film is demolded, it undergoes interlayer gradient cooling through a multi-segment independently temperature-controlled cooling roller system. Each cooling segment sets its cooling rate according to the glass transition temperature or crystallization temperature of its corresponding polymer, maintaining the synchronicity of cooling of each layer and reducing the accumulation of internal stress. Throughout the entire process, an intelligent control system dynamically coordinates and schedules each temperature control node. Based on melt flow rate, film thickness feedback, and historical thermal behavior models, the system automatically adjusts the temperature settings of each region, forming a dynamic closed-loop control system to achieve synchronous thermal behavior and stable interface control between different polymer layers.

[0007] Preferably, the target temperature range is based not only on the polymer's melting temperature, but also comprehensively considers its viscosity-temperature curve, molecular chain mobility change curve, and thermomechanical response window, specifically including the following processes: After selecting the polymer layer material, thermal response data at different heating rates were collected using differential scanning calorimetry, rotational rheometer analysis, and dynamic thermomechanical analysis. By combining the thermal conduction response model of the molding equipment, the optimal processing window suitable for the material under co-extrusion conditions is derived. The set value is taken as the central section of its thermal stability platform, and the fluctuation range is controlled within ±3℃ to ensure the stability of thermal behavior and the uniformity of interfacial energy.

[0008] Preferably, in setting the target temperature range for each polymer layer, a multi-parameter thermophysical model is used for accurate calculation. The multi-parameter thermophysical model is adjusted not only based on the thermal transition point of the material, but also taking into account its dynamic processing behavior. The steps are as follows: The theoretically optimal melting temperature is calculated using the following expression: In the formula, It is the glass transition temperature. It is the material's crystallization temperature. It is the thermal behavior adjustment coefficient. It is the theoretically optimal melting temperature; To ensure that the melt temperature adapts to the system's thermal inertia during co-extrusion, the median processing window is calculated as an intermediate temperature between theory and actual operation. The calculation formula is as follows: In the formula, This is the system's initial temperature rise setpoint. It is the value within the processing window; Considering factors such as heat dissipation of the equipment, heat concentration at the die head, and thermal interference at the material interface, a temperature rise compensation term is introduced to calculate the center value of the target temperature control range. The calculation expression is as follows: In the formula, It is the temperature rise compensation value. It is the center value of the target temperature control range.

[0009] Preferably, the preheating treatment adopts a stepped preheating strategy, which controls the heating process of the polymer raw material particles through three temperature zones, as follows: The first stage is controlled within a slow heating zone 10°C below the material's glass transition temperature to prevent sudden changes in internal stress. The second stage is controlled in the isothermal region 510°C below its melting point, which is used for thermal stability and diffusion equilibrium. The third stage is a short-term rapid increase stage, which allows the particle temperature to reach the transition critical point of 23°C away from its melting temperature in a short time. The entire process uses a closed-loop hot air circulation system to achieve efficient heat reuse, and uses a near-infrared thermal imager to automatically monitor and screen the discharge temperature of each batch of raw material particles to ensure that the temperature deviation when they enter the extruder is controlled within 1.5℃.

[0010] Preferably, a distributed fiber optic temperature sensing system is used to collect the temperature of each extrusion channel in real time. High-density fiber Bragg grating sensing units are installed along the screw barrel and the die outlet, with a spacing of no more than 15 mm, so as to achieve a spatial resolution of less than 0.5℃ for the temperature field. The collected data is connected to the central data processor via a high-speed industrial Ethernet, and combined with a neural network prediction model to judge and warn of temperature fluctuation trends.

[0011] Preferably, the heat-insulating and pressure-isolating channel structure is constructed using multi-layer composite materials. Its core layer is a high-molecular aerogel material with a thermal conductivity of less than 0.15 W / m·K, and the outer layer is coated with a high-temperature resistant ceramic coating to improve structural strength and thermal shock resistance. The channel thickness is controlled to be more than 3 mm. The inner surface of the channel is formed into a three-dimensional micro-groove array through laser micro-engraving, which enhances the guiding and diversion effect of the melt flow in the interface layer, reduces the interface thermal contact area, and reduces the lateral heat conduction path. In addition, the heat insulation channel is equipped with a micro-pressure compensation chamber to alleviate the asymmetric pressure effect of the viscosity gradient caused by the temperature difference on the interface weld line of each melt.

[0012] Preferably, the cooling roller system adopts a five-segment independent temperature control structure. The surface of each cooling roller is covered with a different thermally conductive material coating, which is matched with the thermal diffusion characteristics of the five types of polymer layers. Each segment is equipped with an independent closed-loop liquid cooling system. The cooling medium is a water-glycol mixture with adjustable temperature, and the control accuracy reaches ±0.2℃. To improve cooling uniformity, transverse corrugated grooves are embedded on the surface of the cooling roller to disturb the boundary layer and prevent the formation of cooling blind zones. At the same time, a laser thickness gauge and an infrared thermal imager are installed on the cooling discharge side of each section to measure the changes in film thickness and surface temperature fluctuations of each layer in real time, so as to adjust the surface temperature of the cooling roller and achieve synchronous cooling of each layer.

[0013] Preferably, the intelligent control system adopts a multi-model fusion temperature control scheduling algorithm and integrates a feedforward-feedback hybrid control mechanism; The feedforward module builds a neural network prediction model based on historical batch operation data to quickly estimate the target temperature control parameters; the feedback module receives data streams collected by multiple sensors in real time and calculates the current temperature difference deviation based on the fuzzy logic controller.

[0014] Preferably, when executing the dynamic closed-loop temperature control system scheduling strategy, a multi-stage control consisting of four steps—error detection, weighted judgment, power correction, and actual temperature adjustment—is adopted to achieve high coordination and accelerated response among the temperature control nodes. The specific steps are as follows: At the beginning of each temperature control cycle, the set temperature and the current actual measured temperature are read in real time, and the temperature control error is calculated. The calculation expression is as follows: In the formula, It is the temperature control zone. The target temperature of the node, It is the temperature control zone. The current actual temperature of the node. It is the temperature control zone. Temperature error at the node; The corresponding weight adjustment factor is set based on the magnitude of the current absolute value of the error, and the calculation expression is as follows: In the formula, It is a sensitivity control factor. It is the temperature control zone. The node's weight adjustment factor; Based on the acquired temperature error and weighting adjustment factor Based on empirical gain parameters, the output power adjustment is calculated using the following expression: In the formula, It is the gain adjustment coefficient. It is the temperature control zone. The power adjustment amount of the node; The adjusted power input is converted into a corresponding temperature change using the device's thermal response ratio, and the actual target temperature of the current temperature control zone is updated accordingly. The calculation formula is as follows: In the formula, It is the temperature control zone. The thermal response ratio of the node, It is the temperature control zone. Temperature prediction values ​​after node adjustment.

[0015] The technical effects and advantages provided by the present invention in the above technical solution are as follows: This invention effectively solves the problem of inconsistent temperature control in the co-extrusion process of multilayer polymers by constructing a layered independent temperature control and preheating matching system. In traditional co-extrusion molding processes, due to differences in the melting temperature zones of different polymers, thermal imbalance is prone to occur before the die convergence, leading to hidden defects such as decreased interlayer bonding or interface desorption. This invention introduces a three-stage preheating mechanism before the raw material enters the extrusion machine and employs high-precision segmented temperature control technology in each extrusion channel, combined with a distributed temperature sensing system and fuzzy logic control algorithm, to achieve real-time dynamic temperature control of each layer of melt, ensuring consistent thermal behavior at the die convergence point and significantly improving the stability of the co-extruded structure and the consistency of the film product. Practice shows that this method significantly reduces typical problems such as interfacial non-adhesion and uneven film thickness, greatly improving product yield and processing window tolerance.

[0016] This invention effectively shields interlayer thermal cross-interference by introducing composite thermal insulation and micro-pressure buffer channels into the die structure. Compared to existing processes that indirectly control interfacial thermal behavior solely through temperature settings, this invention employs a multi-layered thermal insulation structure combined with thermal conductive groove guidance technology to construct a physical barrier between material flow nodes, effectively reducing lateral thermal radiation and conduction caused by the high-temperature layer to the low-melting-point material. Simultaneously, the addition of a micro-pressure differential buffer cavity and stress absorption structure further suppresses interfacial disturbances caused by flow rate differences or viscosity abrupt changes, allowing the intermediate functional layer to form stably without being affected by high-temperature disturbances. This active thermal insulation + buffer composite structure results in a clearer film interface and superior physical properties, making it particularly suitable for the precision manufacturing of high-functionality barrier films and high-temperature structural films.

[0017] This invention constructs an intelligent temperature control system with predictive, adaptive, and closed-loop correction capabilities, providing crucial support for the intelligent manufacturing of multilayer polymer films. The system integrates fiber optic temperature sensing monitoring, a neural network controller, a fuzzy logic controller, and an edge computing platform to achieve digital and intelligent management of the entire co-extrusion temperature control process. Under production conditions involving complex material switching and high-frequency process changes, the system can quickly identify abnormal trends in thermal behavior and proactively adjust the temperature control strategies for each area, effectively preventing interface temperature instability caused by response lag in traditional systems. Simultaneously, the system supports online thermal imaging analysis and finished product feedback adjustment, enabling thermal control and quality control to form a closed-loop cycle, significantly improving the self-regulating capability and stability of the production line, reducing the frequency of human intervention, and providing a strong guarantee for the mass production and intelligent manufacturing of high-performance co-extruded products. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a flowchart of the synchronous temperature control method for co-extrusion molding of multilayer polymer films according to the present invention. Detailed Implementation

[0020] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0021] This invention provides, for example Figure 1The synchronous temperature control method shown for co-extrusion molding of multilayer polymer films includes the following steps: Set the target temperature range for each polymer layer of the multilayer polymer film, and determine the extrusion temperature setting and allowable fluctuation range according to the melting characteristics, thermal sensitivity and interfacial adhesion requirements of each layer material. The target temperature range is based not only on the polymer's melting temperature, but also comprehensively considers its viscosity-temperature curve, molecular chain mobility change curve, and thermomechanical response window, specifically including the following processes: After selecting the polymer layer material, thermal response data at different heating rates were collected using differential scanning calorimetry (DSC), rotational rheometer analysis, and dynamic thermomechanical analysis (DMA). By combining the thermal conduction response model of the molding equipment, the optimal processing window suitable for the material under co-extrusion conditions is derived. The set value is taken as the central section of its thermal stability platform, and the fluctuation range is controlled within ±3℃ to ensure the stability of thermal behavior and the uniformity of interfacial energy.

[0022] This method is applicable to thermosensitive thin-layer polymer systems and can effectively prevent uneven thickness and delamination caused by local overmelting or undermelting.

[0023] In setting the target temperature range for each polymer layer, a multi-parameter thermophysical model is used for accurate calculation. The multi-parameter thermophysical model is adjusted not only based on the thermal transition point of the material, but also taking into account its dynamic processing behavior. The steps are as follows: The theoretically optimal melting temperature is calculated using the following expression: In the formula, The glass transition temperature is the critical temperature at which a polymer transitions from a glassy (hard and brittle) state to a rubbery (soft) state. Below this temperature, the polymer molecular chains are almost frozen; above this temperature, the molecular chains begin to move locally. This value is usually obtained by differential scanning calorimetry (DSC) and is an important reference for evaluating the processing properties of heat-sensitive polymers. This is the material's crystallization temperature, representing the temperature at which crystalline regions form in a semi-crystalline polymer during cooling, reflecting the intensity and rate of its crystallization behavior. This value is not applicable to amorphous polymers; instead, the upper limit of their melting plateau is used. This value affects the stable viscosity range of the material's melt and is an important reference for co-extrusion of high-layer structures. This is a thermal behavior adjustment coefficient, ranging from 0.4 to 0.6, used to represent the thermal sensitivity of a polymer as it transitions from a glassy state to a molten state. A higher value indicates a higher flow initiation temperature, while a lower value indicates a more sensitive thermal response. This parameter can be qualitatively set by fitting rheological experimental curves or material handbooks, or it can be extracted from practical temperature control adjustment experience. It is the theoretical optimal melting temperature, which is the ideal processing temperature of the material derived by weighting the thermal behavior between the glass transition and the crystallization region. It serves as the central basis for setting the temperature control range in subsequent co-extrusion. Compared with the melting point measured in actual operation, it has better process adaptability and is particularly suitable for multi-layer collaborative temperature control settings. To ensure that the melt temperature adapts to the system's thermal inertia during co-extrusion, the median processing window is calculated as an intermediate temperature between theory and actual operation. The calculation formula is as follows: In the formula, This is the initial system temperature setpoint, the target heating temperature set at the start of extrusion. It is generally determined by considering the preheating system capacity and the thermal state of the front-end particles. This value controls the thermal energy base of the material before it enters the screw system and is an important parameter affecting the stability of melt start-up. It is usually set by process engineers based on equipment configuration and experience. It is the average value within the processing window, representing the difference between the theoretical melting temperature and the initial temperature rise. It serves as the baseline for the intelligent temperature control system to initially adjust the temperature of each layer of material. It provides a buffer zone, reducing the risk of sudden over-melting or under-melting due to excessively high or low settings, while also laying a stable foundation for subsequent temperature rise compensation. The mean value processing method is used here to provide a stable transition platform between model calculation and actual temperature control.

[0024] Considering factors such as heat dissipation of the equipment, heat concentration at the die head, and thermal interference at the material interface, a temperature rise compensation term is introduced to calculate the center value of the target temperature control range. The calculation expression is as follows: In the formula, This is the temperature rise compensation value, a compensation item set to compensate for the actual temperature deviation caused by factors such as the thermal resistance of the equipment structure, local heat accumulation in the die head, and environmental heat loss. It is typically calculated using simulation software (such as ANSYS Polyflow or COMSOL Multiphysics) to establish a heat conduction model, based on the heat migration path and heat loss of each material within the die head, or by comparing with a large amount of actual production data. The typical value range is between 3℃ and 5℃. It is the center value of the target temperature control range, which is the key target temperature value used to configure the temperature control zone of each polymer layer, and serves as the main setpoint for each heating zone of the temperature control system. This value ensures that the melt temperature is consistent with the center of the theoretical processing window under actual working conditions, and is a basic parameter to prevent thermal migration instability.

[0025] These are empirical compensation values ​​obtained through thermal simulation tools, ensuring the stability of the melt state during continuous production and avoiding the risk of thermal migration instability caused by interlayer temperature differences. This calculation model is applicable to the initial temperature control settings of multilayer co-extrusion under different material laminate structures, improving system adaptability and material co-processing capabilities.

[0026] Before each layer of polymer melt enters an independent screw extruder, the raw material particles are preheated to bring the raw material temperature close to their respective target melting temperature, thereby reducing the impact of temperature rise differences during extrusion on interfacial thermal stability. The preheating process employs a stepped preheating strategy, controlling the heating process of the polymer raw material particles through three temperature zones, as follows: The first stage is controlled within a slow heating zone 10°C below the material's glass transition temperature to prevent sudden changes in internal stress. The second stage is controlled in the isothermal region 510°C below its melting point, which is used for thermal stability and diffusion equilibrium. The third stage is a short-term rapid increase stage, which allows the particle temperature to reach the transition critical point of 23°C away from its melting temperature in a short time. The entire process employs a closed-loop hot air circulation system to achieve efficient heat reuse, and uses a near-infrared thermal imager to automatically monitor and screen the discharge temperature of each batch of raw material particles, ensuring that the temperature deviation when entering the extruder is controlled within 1.5℃, thereby significantly improving the consistency of the subsequent melt output temperature.

[0027] The temperature of each extrusion channel is independently controlled by multiple precision temperature control units, including the screw barrel heating zone, melt conveying channel and each layer of die outlet. Thermocouple data is collected in real time to provide feedback and adjust the output power, ensuring that each layer of melt reaches the set temperature and remains stable before the co-extrusion point. The real-time acquisition of temperature in each extrusion channel adopts a distributed optical fiber temperature sensing system. High-density fiber Bragg grating (FBG) sensing units are installed along the screw barrel and die outlet with a spacing of no more than 15 mm to achieve a spatial resolution of less than 0.5℃ for the temperature field. The collected data is connected to the central data processor via a high-speed industrial Ethernet, and combined with a neural network prediction model to judge and warn of temperature fluctuation trends.

[0028] This system can not only respond to nonlinear behaviors such as sudden changes in material viscosity, but also trigger the intervention of the active cooling unit in advance when the material is blocked or locally heated, effectively suppressing the destructive effect of overheated areas on the co-extrusion quality.

[0029] A heat-insulating and pressure-isolieving channel structure is set in the flow convergence area of ​​the die head to physically isolate the thermal intrusion of the high-temperature melt into the low-temperature layer. A thermal barrier is designed using a thermal conductivity gradient material to limit the rate of lateral heat transfer between layers. The thermal insulation and pressure isolation channel structure is constructed using multi-layer composite materials. Its core layer is a high-molecular aerogel material with a thermal conductivity of less than 0.15 W / m·K, and the outer layer is coated with a high-temperature resistant ceramic coating to improve structural strength and thermal shock resistance. The channel thickness is controlled to be more than 3 mm. The inner surface of the channel is formed into a three-dimensional micro-groove array through laser micro-engraving, which enhances the guiding and diversion effect of the melt flow in the interface layer, reduces the interface thermal contact area, and reduces the lateral heat conduction path. In addition, the heat insulation channel is equipped with a micro-pressure compensation cavity to alleviate the asymmetric pressure effect of the viscosity gradient caused by the temperature difference on the interface weld line of each melt, thereby achieving a thermal pressure equilibrium state of multilayer materials at the microscale.

[0030] In the co-extrusion process of multilayer polymer films, the "high-temperature melt" and "low-temperature layer" typically refer to the use of different polymer materials in the same film structure, each with different melting temperatures and processing heat sensitivities. The high-temperature melt refers to polymers that need to melt and flow at relatively high temperatures, such as polyester (PET), polyamide (PA), and polycarbonate (PC), with a typical processing temperature range of 220°C to 300°C. The low-temperature layer, on the other hand, refers to materials with lower melting temperatures and narrow processing heat windows, such as low-density polyethylene (LDPE), ethylene-vinyl acetate copolymer (EVA), and thermoplastic polyurethane (TPU), with processing temperatures generally between 110°C and 180°C. In the co-extrusion die, these high- and low-temperature melts flow simultaneously in parallel to form a multilayer structure. If temperature control is not precise, the high-temperature layer may cause thermal disturbance to the low-temperature layer, leading to interfacial instability. Therefore, when designing the co-extrusion process, it is essential to strictly distinguish the heat processing zones of different materials to prevent cross-diffusion of heat and resulting interfacial defects.

[0031] Immediately after the film is demolded, it undergoes interlayer gradient cooling through a multi-segment independently temperature-controlled cooling roller system. Each cooling segment sets its cooling rate according to the glass transition temperature or crystallization temperature of its corresponding polymer, maintaining the synchronicity of cooling of each layer and reducing the accumulation of internal stress. The cooling roller system adopts a five-segment independent temperature control structure. The surface of each cooling roller is covered with a different thermally conductive material coating, which is matched with the thermal diffusion characteristics of five types of polymer layers. Each segment is equipped with an independent closed-loop liquid cooling system. The cooling medium is a water-glycol mixture with adjustable temperature, and the control accuracy is ±0.2℃. To improve cooling uniformity, transverse corrugated grooves are embedded on the surface of the cooling roller to disturb the boundary layer and prevent the formation of cooling blind zones. At the same time, a laser thickness gauge and an infrared thermal imager are installed on the cooling discharge side of each section to measure the changes in film thickness and surface temperature fluctuations of each layer in real time, so as to adjust the surface temperature of the cooling roller and achieve synchronous cooling of each layer.

[0032] Throughout the process, an intelligent control system dynamically coordinates and schedules each temperature control node, automatically adjusting the temperature settings of each region based on melt flow rate, film thickness feedback, and historical thermal behavior models, forming a dynamic closed-loop control system to achieve synchronous thermal behavior and stable interface control between different polymer layers. The intelligent control system adopts a multi-model fusion temperature control scheduling algorithm and integrates a feedforward-feedback hybrid control mechanism; The feedforward module builds a neural network prediction model based on historical batch operation data to quickly estimate the target temperature control parameters; the feedback module receives data streams collected by multiple sensors in real time and calculates the current temperature difference deviation based on the fuzzy logic controller.

[0033] The system employs a periodic iterative temperature control scheme, which uses a boundary condition optimization algorithm to adjust the heat input of each temperature control zone in the next cycle, thereby maintaining stable system operation and adapting to different material ratios and external environmental disturbances.

[0034] When implementing the dynamic closed-loop temperature control system scheduling strategy, a multi-stage control consisting of four steps—error detection, weighted judgment, power correction, and actual temperature adjustment—is adopted to achieve high coordination and accelerated response among the temperature control nodes. The specific steps are as follows: At the beginning of each temperature control cycle, the set temperature and the current actual measured temperature are read in real time, and the temperature control error is calculated. The calculation expression is as follows: In the formula, It is the temperature control zone. The target temperature of a node is a theoretical value set based on the optimal processing temperature of the polymer material. It represents the temperature that the temperature control node is expected to maintain and serves as the reference value for closed-loop control. It is the core objective of temperature regulation. It is the temperature control zone. The current actual temperature of the node, measured using thermocouples, infrared sensors, or fiber Bragg grating (FBG) sensors, is compared with the target temperature to determine the deviation of the system's current state and serves as the basis for control adjustments. It is the temperature control zone. The temperature error at a node represents the difference between the target temperature and the measured temperature, indicating the degree of deviation of the system's temperature control. A positive error value indicates insufficient temperature, requiring heating; a negative error value indicates excessive temperature, requiring cooling. The magnitude of the error directly affects the control output. This error value is used to determine the degree of deviation of each temperature control zone from its target state, serving as the primary driving variable for regulation.

[0035] The corresponding weight adjustment factor is set based on the magnitude of the current absolute value of the error, and the calculation expression is as follows: In the formula, This is the control sensitivity factor, used to adjust the degree of influence of errors on the weights of the control system. It reflects the system's sensitivity to temperature errors, and its value range is manually set by the system commissioning personnel based on the material's thermal response rate and the system's thermal inertia. It is usually between 0.1 and 0.5. The larger the β value, the more conservative the system is in response to errors, and the slower the response; the smaller the value, the more aggressive the system response. It is used to prevent system overshoot or oscillation. It is the temperature control zone. The node weight adjustment factor reduces the power adjustment amplitude to stabilize the system when the error is large, and improves the adjustment efficiency and enhances the precision control when the error is small. This formula ensures that the larger the error, the lower the weight of the control output, thereby avoiding system oscillation or temperature overshoot caused by the controller overreacting.

[0036] Based on the acquired temperature error and weighting adjustment factor Based on empirical gain parameters, the output power adjustment is calculated using the following expression: In the formula, This is the gain adjustment coefficient, an amplification factor for the controller's error correction actions. It determines the rate of change of the actual power output under a given error condition, thus determining the controller's "strength." Too high a value may cause temperature overshoot, while too low a value may lead to sluggish control. It typically needs to be optimized during system operation. It is the temperature control zone. The power adjustment of the node, combined with temperature error, control sensitivity and system gain, is the heat input adjustment value, which can be expressed in watts. It guides the system to increase or decrease the amount of heat input in the next control cycle and is the core output variable of temperature control response. This power adjustment is applied to the actual controller of each heating unit to correct the heat flow input of the heater or cooling module.

[0037] The adjusted power input is converted into a corresponding temperature change using the device's thermal response ratio, and the actual target temperature of the current temperature control zone is updated accordingly. The calculation formula is as follows: In the formula, It is the temperature control zone. The node's thermal response ratio is used to convert power regulation values ​​into specific temperature adjustment amounts, reflecting the actual physical coupling relationship between thermal energy and temperature changes. It is the temperature control zone. The adjusted temperature prediction value of the node, after applying power regulation, is the temperature that the temperature control zone is expected to reach in the next moment. It serves as a feedback reference for dynamic control and is used as the basis for adjusting the controller feedforward module in the next cycle, thereby improving the system response accuracy and stability.

[0038] Through the aforementioned dynamic control process, precise temperature tracking and real-time adjustment are achieved during the processing of each polymer layer. This ensures stable and rapid response of the thermal field control during co-extrusion molding, making it particularly suitable for continuous production environments of high-layer film structures or combinations of heat-sensitive materials. The algorithm possesses high stability, high adaptability, and system anti-interference performance, making it a key module for ensuring the intelligent operation of the temperature control system in complex multi-layer co-extrusion production.

[0039] Implementation Method 1: In the co-extrusion molding process of multilayer polymer films, if there are significant differences in the melting temperature and thermal sensitivity of the polymers used in each layer, without intervention, a "thermal migration instability" phenomenon can easily occur in the die-joining area, leading to a weak interface layer structure, reduced bonding strength, and even delamination or breakage during subsequent use. To address this critical issue, this implementation method adopts a thermal field coordination strategy of "independent temperature control for each layer + staged preheating" to ensure that each polymer layer is always under optimal temperature control throughout the entire process from raw material feeding to melt co-extrusion, thus curbing the risk of thermal migration at its source.

[0040] In practice, each polymer is first stored in separate compartments according to its layer, and each is equipped with an independent preheating unit. Taking a typical five-layer structure (PP / EVA / PA / PE / PET) as an example, each type of raw material granules is processed through a three-stage preheating system. The first stage is the initial heating zone, which slowly heats the raw material to about 10°C below its glass transition temperature. The main purpose is to relieve the structural stress of the material in its cold state and avoid micro-cracks caused by sudden temperature rise. The second stage is the thermal stabilization zone, which stably controls the temperature between 5 and 10°C below the material's melting point, making the internal heat distribution of the granules more uniform and contributing to the stability of the subsequent melting process. The third stage is the rapid heating zone, which heats the granules to the melting point front in a short time as a transitional treatment before screw extrusion.

[0041] Next, the raw materials enter extruders with different screw structures. To address the viscosity variations and differences in heat sensitivity of different materials, a multi-segment temperature-controlled heating mantle and a forced air-cooling module are used for coordinated adjustment. The temperature control range for each segment is precisely set, with a response rate within 200ms. The system incorporates temperature monitoring nodes, spaced no more than 10mm apart, using fiber Bragg grating sensing units with a spatial resolution better than 0.5℃. All sensor data is aggregated to the central control system, equipped with an edge computing module and a fuzzy logic controller, to analyze the temperature status and fluctuation trends of each segment in real time. If the temperature in a certain area deviates from the set value by more than 1.5℃, the system automatically adjusts the power of the corresponding heating module or triggers the forced cooling mechanism.

[0042] The most crucial aspect is the thermal behavior management of the die head confluence section. Since all the melt will eventually converge here to form a multi-layer structure, the system is specially equipped with a "thermal coupling adjustment module". Based on the melt flow rate, viscosity, preset film thickness ratio, and upstream and downstream temperature difference of each layer, it dynamically calculates the thermal compensation amount at the exit of each die head, and maintains the thermal matching of each layer of material at the moment of contact by finely controlling the interface temperature through an independent annular heater.

[0043] After processing in this way, in practical applications, it is not necessary to completely re-adjust the system parameters when switching between different batches of materials. Only by importing the historical thermal behavior model and making appropriate fine-tuning of the preheating and die head temperature control sections, stable production can be achieved. Statistical results show that the system effectively reduces the interface delamination rate by about 72%, controls the product thickness deviation within ±3%, and significantly improves the overall structural stability and continuous molding efficiency of the co-extruded film.

[0044] Implementation Method 2: In some multilayer thin film applications, combinations of heat-sensitive materials and high-melting-point materials are often involved, such as the structure where the gas barrier layer EVOH is sandwiched between PET and PE. This structure places extremely high demands on thermal control. Once the high-temperature layer causes thermal disturbance to the intermediate layer, it can easily lead to excessive melting at the interface and adhesion failure, and may even trigger a degradation reaction of the EVOH material, affecting the film's gas barrier performance and service life. To address this, this implementation method designs a physical heat insulation-pressure isolation structure, constructing a thermal barrier in the die head convergence area to block the lateral heat transfer pathway at the structural level.

[0045] The structure mainly consists of three parts: first, the intermediate filling layer, which is a high-performance nano-aerogel material with a thickness of 5 mm and a thermal conductivity of less than 0.1 W / m·K. It can still maintain good thermal insulation performance and block heat penetration under high temperature environment; second, the outer coating layer, which is composed of a high-temperature resistant zirconia ceramic coating, which not only enhances the mechanical structure strength, but also has excellent thermal radiation reflection performance; and third, the microfluidic guiding layer, which uses laser engraving technology to process a micro-groove array on the aerogel surface. The arrangement is based on a cross grid layout, which significantly increases the thermal flow path of the boundary layer and effectively delays the heat transfer time.

[0046] In addition, micro-pressure buffer cavities are set at both ends of the heat insulation channel, which are filled with elastic silicone rubber diaphragms, and each cavity is equipped with a one-way pressure relief valve. When the high-temperature melt enters the die head and causes pressure disturbance due to pressure difference, the diaphragm absorbs part of the stress, maintains the pressure symmetry at the co-extrusion port, and prevents the local interface from cracking due to excessive compressive strain.

[0047] After applying this structure, in testing the PET+EVOH+PE three-layer film, even with a processing temperature as high as 280℃ for the PET layer, the EVOH layer maintained intact interfacial bonding at a controlled temperature of 175℃. Microscopic analysis showed no melt penetration traces, and the thickness fluctuation was less than 2 micrometers. Gas barrier performance was improved by 22%, interlayer peel strength was increased by more than 30%, and the film showed no bubbles or delamination in the 180℃ heat-sealing test, demonstrating good industrial applicability.

[0048] Implementation Method 3: In modern multilayer polymer film production processes, to meet increasingly complex functional and high-performance requirements, production lines need to frequently switch material types, film thickness specifications, and environmental parameters. This places extremely high demands on the adaptability and adjustment accuracy of the temperature control system. Traditional manual setting and static PID control are no longer sufficient to meet the needs of high-frequency adjustment and dynamic coordination. Therefore, this implementation method adopts industrial Internet of Things (IoT) technology to construct a self-learning, self-adjusting, and self-feedback intelligent closed-loop temperature control system to achieve dynamic adjustment of thermal behavior throughout the entire process.

[0049] At the equipment structure level, each extrusion channel, die section, and cooling section is equipped with a temperature control unit and a fiber Bragg grating temperature sensor. The spacing between each sensing point is within 10mm, the temperature measurement accuracy reaches 0.3℃, and the response time is less than 200ms. Each sensing node is connected to the central control server via industrial Ethernet. The server runs a deep neural network model trained based on historical data and generates a preliminary temperature control strategy based on the raw material DSC curve, target film thickness, equipment parameters, etc.

[0050] During production, the system scans the entire network of sensor data once per second. If a temperature difference exceeding 1°C is detected in a certain section, the system immediately uses a fuzzy inference algorithm to deduce the cause of the temperature difference and automatically adjusts the power output of the heating modules. Simultaneously, the system analyzes whether there is coupled thermal interference in neighboring sections and uses a weighted adjustment mechanism to synchronously adjust adjacent nodes. The entire control logic iterates continuously, fine-tuning parameters every 10 minutes and performing a model retraining cycle every 6 hours, ensuring the system remains adaptable to new materials and environmental changes.

[0051] Furthermore, the system integrates infrared thermal imaging analysis and laser thickness measurement feedback mechanisms to correct interlayer thickness variations in real time. When layer thickness fluctuations exceed preset values ​​or interface temperature deviations continue to widen, the system automatically triggers an alarm and generates control suggestions in the background for manual review. In practice, the system has reduced product defect rates by nearly 70% and significantly improved production stability, providing a reliable guarantee for enterprises to achieve continuous, intelligent, and flexible multi-variety manufacturing.

[0052] This invention effectively solves the problem of inconsistent temperature control in the co-extrusion process of multilayer polymers by constructing a layered independent temperature control and preheating matching system. In traditional co-extrusion molding processes, due to differences in the melting temperature zones of different polymers, thermal imbalance is prone to occur before the die convergence, leading to hidden defects such as decreased interlayer bonding or interface desorption. This invention introduces a three-stage preheating mechanism before the raw material enters the extrusion machine and employs high-precision segmented temperature control technology in each extrusion channel, combined with a distributed temperature sensing system and fuzzy logic control algorithm, to achieve real-time dynamic temperature control of each layer of melt, ensuring consistent thermal behavior at the die convergence point and significantly improving the stability of the co-extruded structure and the consistency of the film product. Practice shows that this method significantly reduces typical problems such as interfacial non-adhesion and uneven film thickness, greatly improving product yield and processing window tolerance.

[0053] This invention effectively shields interlayer thermal cross-interference by introducing composite thermal insulation and micro-pressure buffer channels into the die structure. Compared to existing processes that indirectly control interfacial thermal behavior solely through temperature settings, this invention employs a multi-layered thermal insulation structure combined with thermal conductive groove guidance technology to construct a physical barrier between material flow nodes, effectively reducing lateral thermal radiation and conduction caused by the high-temperature layer to the low-melting-point material. Simultaneously, the addition of a micro-pressure differential buffer cavity and stress absorption structure further suppresses interfacial disturbances caused by flow rate differences or viscosity abrupt changes, allowing the intermediate functional layer to form stably without being affected by high-temperature disturbances. This active thermal insulation + buffer composite structure results in a clearer film interface and superior physical properties, making it particularly suitable for the precision manufacturing of high-functionality barrier films and high-temperature structural films.

[0054] This invention constructs an intelligent temperature control system with predictive, adaptive, and closed-loop correction capabilities, providing crucial support for the intelligent manufacturing of multilayer polymer films. The system integrates fiber optic temperature sensing monitoring, a neural network controller, a fuzzy logic controller, and an edge computing platform to achieve digital and intelligent management of the entire co-extrusion temperature control process. Under production conditions involving complex material switching and high-frequency process changes, the system can quickly identify abnormal trends in thermal behavior and proactively adjust the temperature control strategies for each area, effectively preventing interface temperature instability caused by response lag in traditional systems. Simultaneously, the system supports online thermal imaging analysis and finished product feedback adjustment, enabling thermal control and quality control to form a closed-loop cycle, significantly improving the self-regulating capability and stability of the production line, reducing the frequency of human intervention, and providing a strong guarantee for the mass production and intelligent manufacturing of high-performance co-extruded products.

[0055] The above formulas are all dimensionless calculations. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art according to the actual situation.

[0056] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

[0057] It should be noted that, in this document, the use of relational terms such as "first" and "second" is merely for distinguishing one entity or operation from another, and does not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0058] It should be understood that in the various embodiments of this application, the order of the above-mentioned processes does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0059] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0060] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0061] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0062] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0063] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0064] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A synchronous temperature control method for co-extrusion molding of multilayer polymer films, characterized in that, Includes the following steps: Set the target temperature range for each polymer layer of the multilayer polymer film, and determine the extrusion temperature setting and allowable fluctuation range according to the melting characteristics, thermal sensitivity and interfacial adhesion requirements of each layer material. Before each layer of polymer melt enters an independent screw extruder, the raw material particles are preheated to bring the raw material temperature close to their respective target melting temperature, thereby reducing the impact of temperature rise differences during extrusion on interfacial thermal stability. The temperature of each extrusion channel is independently controlled by multiple precision temperature control units, including the screw barrel heating zone, melt conveying channel and each layer of die outlet. Thermocouple data is collected in real time to provide feedback and adjust the output power, ensuring that each layer of melt reaches the set temperature and remains stable before the co-extrusion point. A heat-insulating and pressure-isolieving channel structure is set in the flow convergence area of ​​the die head to physically isolate the thermal intrusion of the high-temperature melt into the low-temperature layer. A thermal barrier is designed using a thermal conductivity gradient material to limit the rate of lateral heat transfer between layers. Immediately after the film is demolded, it undergoes interlayer gradient cooling through a multi-segment independently temperature-controlled cooling roller system. Each cooling segment sets its cooling rate according to the glass transition temperature or crystallization temperature of its corresponding polymer, maintaining the synchronicity of cooling of each layer and reducing the accumulation of internal stress. Throughout the entire process, an intelligent control system dynamically coordinates and schedules each temperature control node. Based on melt flow rate, film thickness feedback, and historical thermal behavior models, the system automatically adjusts the temperature settings of each region, forming a dynamic closed-loop control system to achieve synchronous thermal behavior and stable interface control between different polymer layers.

2. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The target temperature range is based not only on the polymer's melting temperature, but also comprehensively considers its viscosity-temperature curve, molecular chain mobility change curve, and thermomechanical response window, specifically including the following processes: After selecting the polymer layer material, thermal response data at different heating rates were collected using differential scanning calorimetry, rotational rheometer analysis, and dynamic thermomechanical analysis. By combining the thermal conduction response model of the molding equipment, the optimal processing window suitable for the material under co-extrusion conditions is derived. The set value is taken as the central section of its thermal stability platform, and the fluctuation range is controlled within ±3℃ to ensure the stability of thermal behavior and the uniformity of interfacial energy.

3. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, In setting the target temperature range for each polymer layer, a multi-parameter thermophysical model is used for accurate calculation. The multi-parameter thermophysical model is adjusted not only based on the thermal transition point of the material, but also taking into account its dynamic processing behavior. The steps are as follows: The theoretically optimal melting temperature is calculated using the following expression: In the formula, It is the glass transition temperature. It is the material's crystallization temperature. It is the thermal behavior adjustment coefficient. It is the theoretically optimal melting temperature; To ensure that the melt temperature adapts to the system's thermal inertia during co-extrusion, the median processing window is calculated as an intermediate temperature between theory and actual operation. The calculation formula is as follows: In the formula, This is the system's initial temperature rise setpoint. It is the value within the processing window; Considering factors such as heat dissipation of the equipment, heat concentration at the die head, and thermal interference at the material interface, a temperature rise compensation term is introduced to calculate the center value of the target temperature control range. The calculation expression is as follows: In the formula, It is the temperature rise compensation value. It is the center value of the target temperature control range.

4. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The preheating process employs a stepped preheating strategy, controlling the heating process of the polymer raw material particles through three temperature zones, as follows: The first stage is controlled within a slow heating zone 10°C below the material's glass transition temperature to prevent sudden changes in internal stress. The second stage is controlled in the isothermal region 510°C below its melting point, which is used for thermal stability and diffusion equilibrium. The third stage is a short-term rapid increase stage, which allows the particle temperature to reach the transition critical point of 23°C away from its melting temperature in a short time. The entire process uses a closed-loop hot air circulation system to achieve efficient heat reuse, and uses a near-infrared thermal imager to automatically monitor and screen the discharge temperature of each batch of raw material particles to ensure that the temperature deviation when they enter the extruder is controlled within 1.5℃.

5. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The real-time acquisition of temperature in each extrusion channel adopts a distributed optical fiber temperature sensing system. High-density fiber Bragg grating sensing units are installed along the screw barrel and die outlet, with a spacing of no more than 15 mm, so as to achieve a spatial resolution of less than 0.5℃ for the temperature field. The collected data is connected to the central data processor via a high-speed industrial Ethernet, and combined with a neural network prediction model to judge and warn of temperature fluctuation trends.

6. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The thermal insulation and pressure isolation channel structure is constructed using multi-layer composite materials. Its core layer is a high-molecular aerogel material with a thermal conductivity of less than 0.15 W / m·K, and the outer layer is coated with a high-temperature resistant ceramic coating to improve structural strength and thermal shock resistance. The channel thickness is controlled to be more than 3 mm. The inner surface of the channel is formed into a three-dimensional micro-groove array through laser micro-engraving, which enhances the guiding and diversion effect of the melt flow in the interface layer, reduces the interface thermal contact area, and reduces the lateral heat conduction path. In addition, the heat insulation channel is equipped with a micro-pressure compensation chamber to alleviate the asymmetric pressure effect of the viscosity gradient caused by the temperature difference on the interface weld line of each melt.

7. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The cooling roller system adopts a five-segment independent temperature control structure. The surface of each cooling roller is covered with a different thermally conductive material coating, which is matched with the thermal diffusion characteristics of five types of polymer layers. Each segment is equipped with an independent closed-loop liquid cooling system. The cooling medium is a water-glycol mixture with adjustable temperature, and the control accuracy is ±0.2℃. To improve cooling uniformity, transverse corrugated grooves are embedded on the surface of the cooling roller to disturb the boundary layer and prevent the formation of cooling blind zones. At the same time, a laser thickness gauge and an infrared thermal imager are installed on the cooling discharge side of each section to measure the changes in film thickness and surface temperature fluctuations of each layer in real time, so as to adjust the surface temperature of the cooling roller and achieve synchronous cooling of each layer.

8. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, The intelligent control system adopts a multi-model fusion temperature control scheduling algorithm and integrates a feedforward-feedback hybrid control mechanism; The feedforward module builds a neural network prediction model based on historical batch operation data to quickly estimate the target temperature control parameters; the feedback module receives data streams collected by multiple sensors in real time and calculates the current temperature difference deviation based on the fuzzy logic controller.

9. The synchronous temperature control method for co-extrusion molding of multilayer polymer films according to claim 1, characterized in that, When implementing the dynamic closed-loop temperature control system scheduling strategy, a multi-stage control consisting of four steps—error detection, weighted judgment, power correction, and actual temperature adjustment—is adopted to achieve high coordination and accelerated response among the temperature control nodes. The specific steps are as follows: At the beginning of each temperature control cycle, the set temperature and the current actual measured temperature are read in real time, and the temperature control error is calculated. The calculation expression is as follows: In the formula, It is the temperature control zone. The target temperature of the node, It is the temperature control zone. The current actual temperature of the node. It is the temperature control zone. Temperature error at the node; The corresponding weight adjustment factor is set based on the magnitude of the current absolute value of the error, and the calculation expression is as follows: In the formula, It is a sensitivity control factor. It is the temperature control zone. The node's weight adjustment factor; Based on the acquired temperature error and weighting adjustment factor Based on empirical gain parameters, the output power adjustment is calculated using the following expression: In the formula, It is the gain adjustment coefficient. It is the temperature control zone. The power adjustment amount of the node; The adjusted power input is converted into a corresponding temperature change using the device's thermal response ratio, and the actual target temperature of the current temperature control zone is updated accordingly. The calculation formula is as follows: In the formula, It is the temperature control zone. The thermal response ratio of the node, It is the temperature control zone. Temperature prediction values ​​after node adjustment.

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