PET packing belt extrusion forming temperature self-adaptive control method

Abstract

The application relates to the technical field of PET packing belt forming temperature control, and discloses a PET packing belt extrusion forming temperature self-adaptive control method, which comprises the following steps: collecting raw material type information corresponding to PET packing belt to be extruded, and determining a forming temperature range based on the raw material type information; determining an optimal forming sub-temperature which makes the forming state meet preset performance indexes; in the process of extruding the PET packing belt to be extruded at the optimal forming sub-temperature, judging whether a water content rate parameter exceeds a water content rate parameter threshold value; if yes, collecting running state parameters of an extrusion forming device, determining a first temperature compensation amount according to the water content rate parameter, and determining a second temperature compensation amount according to the running state parameters; and obtaining an optimal forming temperature based on the optimal forming sub-temperature, the first temperature compensation amount and the second temperature compensation amount. The application improves temperature control precision, reduces belt defects, and improves PET packing belt forming quality and production stability.

Description

Technical Field

[0001] This invention relates to the field of PET strapping molding temperature control technology, and more specifically, to an adaptive control method for PET strapping extrusion molding temperature. Background Technology

[0002] PET (Polyethylene Terephthalate) strapping is widely used for packaging and bundling various items, such as cartons, wooden crates, and pallets, due to its excellent properties including high strength, high toughness, wear resistance, corrosion resistance, light weight, and recyclability. In the production process of PET strapping, extrusion molding is a crucial step, and extrusion temperature is one of the core process parameters affecting the quality and efficiency of extrusion molding.

[0003] Traditional PET strapping extrusion molding temperature control often relies on empirical settings or simple PID feedback regulation. However, the physical properties of PET raw materials vary from batch to batch, and during extrusion, factors such as ambient temperature fluctuations, screw speed changes, uneven feeding speeds, and die conditions all significantly affect the actual molding temperature. These complex and dynamically changing interference factors make it difficult to accurately control the extrusion molding temperature in real time using fixed temperature settings or simple feedback regulation. This can easily lead to uneven plasticization of the extruded material, melt pressure fluctuations, and consequently, quality problems such as thickness deviations, surface defects, and unstable mechanical properties in the strapping. Furthermore, improper temperature control may also lead to raw material degradation or increased energy consumption, reducing production efficiency and product qualification rates.

[0004] Therefore, it is necessary to design an adaptive control method for the extrusion molding temperature of PET strapping to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes an adaptive control method for the extrusion molding temperature of PET strapping, which aims to solve the problem that traditional PET strapping extrusion molding temperature control methods are difficult to achieve accurate control when facing complex dynamic disturbances.

[0006] This invention proposes an adaptive control method for the extrusion molding temperature of PET strapping, comprising the following steps: Collect the raw material type information corresponding to the PET packing tape to be extruded, and determine the molding temperature range based on the raw material type information; Based on the molding temperature range, several temperature sampling points are selected through a segmented step size strategy for extrusion tests to determine the optimal molding temperature that makes the molding state meet the preset performance indicators. During the extrusion process of the PET packing tape to be extruded at the optimal molding temperature, the moisture content parameter of the PET raw material is collected, and it is determined whether the moisture content parameter exceeds the moisture content parameter threshold. If so, collect the operating status parameters of the extrusion molding device, determine the first temperature compensation amount based on the moisture content parameter, and determine the second temperature compensation amount based on the operating status parameters; Based on the optimal molding temperature, the first temperature compensation amount, and the second temperature compensation amount, the optimal molding temperature is obtained, and the temperature control system of the extrusion molding device is adjusted according to the optimal molding temperature.

[0007] Furthermore, when determining the molding temperature range based on the raw material type information, the following steps are included: The raw material type information is parsed to obtain the category attributes of the PET raw material; wherein, the category attributes include virgin material, recycled material, and combinations thereof; Obtain the basic temperature range data corresponding to the category attribute; The characteristic parameters of the PET raw material are obtained based on the raw material type information; wherein, the characteristic parameters include intrinsic viscosity, filler ratio and additive type; The base temperature range data is corrected based on the aforementioned characteristic parameters to obtain the target temperature range; The target temperature range is defined as the molding temperature range.

[0008] Further, when correcting the basic temperature range data based on the characteristic parameters to obtain the target temperature range, the following steps are included: The characteristic parameters are quantified to obtain corresponding parameter values; wherein, the parameter values ​​include intrinsic viscosity, filling ratio, and additive content. Based on the preset parameter-temperature mapping relationship, the temperature correction amount corresponding to each parameter value is determined respectively; The various temperature correction values ​​are weighted to obtain a comprehensive temperature correction value. Based on the baseline temperature range data and the comprehensive temperature correction amount, the upper limit and / or lower limit of the baseline temperature range are adjusted to obtain the target temperature range.

[0009] Furthermore, when selecting several temperature sampling points for extrusion testing using a segmented step-size strategy, the following steps are included: Obtain the range span information of the basic temperature range, and determine the initial step size range based on the range span information; Collect correlation data between temperature changes and molding state changes during historical extrusion processes, and establish a temperature sensitivity evaluation index; The initial step size range is adjusted according to the temperature sensitivity evaluation index to obtain the segmented step size strategy; During the selection of temperature sampling points, the molding temperature range is non-uniformly divided based on the segmented step size strategy to obtain several temperature sampling points.

[0010] Furthermore, determining the optimal molding temperature that ensures the molding state meets preset performance indicators includes: Collect the strip defect parameters corresponding to each temperature sampling point, and quantify the defect parameters to obtain defect characterization values; wherein, the defect parameters include surface defects, internal bubble defects, and dimensional deviations; The defect characterization values ​​are comprehensively calculated to obtain the defect evaluation index corresponding to each temperature sampling point; The temperature sampling point with the best defect evaluation index is selected as the candidate optimal temperature, and local densification sampling is performed in the neighborhood of the candidate optimal temperature according to the step size decreasing rule. Based on the local sampling results, a response relationship between temperature and defect evaluation index is constructed, and the temperature corresponding to the extreme point is determined as the optimal molding temperature based on the response relationship.

[0011] Further, when collecting the moisture content parameter of the PET raw material and determining whether the moisture content parameter exceeds the moisture content parameter threshold, the process includes: The moisture content parameter of the PET raw material is obtained by online detection, and the moisture content parameter is filtered to obtain the target moisture content parameter. The target moisture content parameter is compared with the moisture content parameter threshold, and a moisture deviation index is constructed by combining the rate of change of moisture content. The defect risk level used to characterize the trend of bubble defect occurrence is determined based on the moisture deviation index. When the defect risk level exceeds the preset level threshold, the abnormal moisture content judgment result is output and the temperature compensation calculation is triggered.

[0012] Further, when determining the first temperature compensation amount based on the moisture content parameter, the following steps are included: Extract the moisture deviation intensity parameter corresponding to the moisture deviation index; The effective moisture content in a unit mass of PET raw material is calculated based on the moisture deviation intensity parameter. Calculate the amount of thermal disturbance generated by water vaporization based on the effective moisture content; Determine the temperature compensation base value based on the thermal disturbance amount; The temperature compensation base value is corrected based on the rate of change of moisture content to obtain the temperature compensation amount, and the temperature compensation amount is used as the first temperature compensation amount.

[0013] Further, when correcting the temperature compensation base value based on the rate of change of moisture content to obtain the temperature compensation amount, the following steps are included: The rate of change of moisture content is compared with the first rate of change of moisture content and the second rate of change of moisture content, and the temperature correction coefficient of the temperature compensation base value is determined based on the comparison result; wherein, the first rate of change of moisture content is less than the second rate of change of moisture content. When the rate of change of moisture content is less than or equal to the rate of change of moisture content, the temperature correction coefficient is determined to be the first temperature correction coefficient. When the rate of change of moisture content is greater than the rate of change of the first moisture content and less than or equal to the rate of change of the second moisture content, the temperature correction coefficient is determined to be the second temperature correction coefficient. When the rate of change of moisture content is greater than the rate of change of the second moisture content, the temperature correction coefficient is determined to be the third temperature correction coefficient. The temperature compensation base value is multiplied by the temperature correction coefficient to obtain the temperature compensation amount.

[0014] Further, determining the second temperature compensation amount based on the operating status parameters includes: The operating status parameters are analyzed to obtain the screw speed, barrel pressure, and material flow fluctuation amplitude of the extrusion molding device; The material flow uniformity index of the extrusion molding device is calculated based on the screw speed, barrel pressure, and material flow fluctuation amplitude. Collect screw torque and melt viscosity data, and calculate the shear energy matching difference; The temperature change rate of each heating section of the barrel and the die head is collected, the temperature response curve is fitted, and the thermal inertia correction is calculated. Collect information on changes in cooling water temperature and calculate the cooling adjustment amount; The material flow uniformity index, shear energy matching difference, thermal inertia correction amount, and cooling adjustment amount are multiplied by the corresponding temperature correction direction factor, and then weighted and summed according to their respective weights to obtain the comprehensive temperature correction amount, which is then used as the second temperature compensation amount.

[0015] Further, when obtaining the optimal molding temperature based on the optimal molding sub-temperature, the first temperature compensation amount, and the second temperature compensation amount, the process includes: The optimal molding temperature is added to the first temperature compensation amount and the second temperature compensation amount to obtain the preliminary adjustment temperature; The initial temperature adjustment is smoothed to obtain a smooth temperature; Based on the screw speed, barrel pressure and material flow fluctuation amplitude, the temperature regulation safety boundary is calculated, and the smoothing temperature is limited within the safety boundary to obtain the safe limit temperature. The safety limit temperature is used as the optimal molding temperature of the extrusion molding device, and an adjustment command is output to the temperature control system for temperature control.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention achieves refined and adaptive control of the PET strapping extrusion molding temperature by adaptively determining the molding temperature range based on raw material type, selecting the optimal molding sub-temperature using a segmented step-size strategy, and performing real-time dynamic temperature compensation based on changes in PET raw material moisture content and the operating parameters of the extrusion molding device. Specifically, the molding temperature range is first determined and corrected based on the PET raw material's category attributes and characteristic parameters, laying the foundation for precise temperature control. Temperature sampling experiments are conducted using a segmented step-size strategy, combined with strip defect parameter analysis and localized intensified sampling, to find the optimal molding sub-temperature that meets preset performance indicators. During actual extrusion, moisture content parameter monitoring and defect risk level assessment are introduced. When moisture content is abnormal, a first temperature compensation amount is calculated based on the moisture deviation and rate of change to address thermal disturbances; a second temperature compensation amount is calculated by analyzing operating parameters such as screw speed to offset the impact of dynamic changes in equipment operation on temperature. Finally, by integrating the optimal molding sub-temperature and the two types of compensation amounts and defining safety boundaries, the optimal molding temperature is obtained and implemented, improving temperature control accuracy, reducing strip defects, enhancing the molding quality and production stability of PET strapping, and reducing scrap rates. This has significant engineering application value and economic benefits. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart of an adaptive control method for PET strapping extrusion molding temperature provided in an embodiment of the present invention. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, embodiments and features in the embodiments of the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] See Figure 1 As shown in some embodiments of this application, this embodiment provides an adaptive control method for the extrusion molding temperature of PET strapping, including the following steps: S100: Collect information on the raw material type of the PET strapping to be extruded, and determine the molding temperature range based on the raw material type information; S200: Based on the molding temperature range, several temperature sampling points are selected through a segmented step size strategy to conduct extrusion tests and determine the optimal molding sub-temperature that makes the molding state meet the preset performance indicators. S300: During the extrusion process of the PET packing tape to be extruded at the optimal molding temperature, the moisture content parameter of the PET raw material is collected, and it is determined whether the moisture content parameter exceeds the moisture content parameter threshold. S400: If so, collect the operating status parameters of the extrusion molding device, determine the first temperature compensation amount based on the moisture content parameter, and determine the second temperature compensation amount based on the operating status parameters; S500: Based on the optimal molding temperature, the first temperature compensation amount, and the second temperature compensation amount, the optimal molding temperature is obtained, and the temperature control system of the extrusion molding device is adjusted according to the optimal molding temperature.

[0020] It is understandable that this embodiment adaptively determines the molding temperature range based on raw material type, selects the optimal molding sub-temperature using a segmented step-size strategy, and performs real-time dynamic temperature compensation based on changes in PET raw material moisture content and the operating parameters of the extrusion molding device, achieving refined and adaptive control of the PET strapping extrusion molding temperature. Specifically, the molding temperature range is first determined and corrected based on the PET raw material category attributes and characteristic parameters, laying the foundation for precise temperature control. Temperature sampling experiments are conducted using a segmented step-size strategy, combined with strip defect parameter analysis and localized intensified sampling, to find the optimal molding sub-temperature that meets preset performance indicators. During actual extrusion, moisture content parameter monitoring and defect risk level assessment are introduced. When the moisture content is abnormal, a first temperature compensation amount is calculated based on the moisture deviation and rate of change to address thermal disturbances; operating parameters such as screw speed are analyzed to calculate a second temperature compensation amount to offset the impact of dynamic changes in equipment operation on temperature. Finally, the optimal molding sub-temperature and the two types of compensation amounts are integrated, and a safety boundary is defined to obtain and execute the optimal molding temperature, improving temperature control accuracy, reducing strip defects, improving the molding quality and production stability of PET strapping, and reducing the scrap rate, which has significant engineering application value and economic benefits.

[0021] Specifically, when determining the molding temperature range based on raw material type information, the following are included: The raw material type information is parsed to obtain the category attributes of PET raw materials; among which, the category attributes include virgin materials, recycled materials and their combinations. Retrieve the basic temperature range data corresponding to the category attribute; The characteristic parameters of PET raw materials are obtained based on the raw material type information; among which, the characteristic parameters include intrinsic viscosity, filler ratio and additive type. The base temperature range data is corrected based on the characteristic parameters to obtain the target temperature range; The target temperature range is defined as the molding temperature range.

[0022] Understandably, obtaining the baseline temperature range data corresponding to the category attributes involves finding or extracting matching recommended extrusion temperature ranges from existing process experience, material handbooks, or historical extrusion experiments based on the PET raw material category attributes (virgin, recycled, or a mixture thereof). This serves as the initial reference range for subsequent temperature adjustments and optimizations. For example, the baseline temperature range for 100% virgin material is set at 260℃-280℃. For a mixed raw material with 30% recycled material, the baseline temperature range might be adjusted to 250℃-270℃, because the molecular chains of recycled material may break after multiple processing, resulting in a slightly lower melting temperature than virgin material. Characteristic parameters are obtained through experimental testing or technical data provided by raw material suppliers.

[0023] Specifically, when correcting the base temperature range data based on characteristic parameters to obtain the target temperature range, the following steps are included: The characteristic parameters are quantified to obtain the corresponding parameter values; among them, the parameter values ​​include intrinsic viscosity, filling ratio, and additive content. Based on the preset parameter-temperature mapping relationship, the temperature correction amount corresponding to each parameter value is determined respectively; The various temperature correction values ​​are weighted to obtain the comprehensive temperature correction value. Based on the baseline temperature range data and the comprehensive temperature correction, the upper and / or lower limits of the baseline temperature range are adjusted to obtain the target temperature range.

[0024] Understandably, the parameter-temperature mapping relationship is a mathematical model or reference table constructed from a large amount of experimental data and process experience, used to describe the correspondence between characteristic parameter values ​​and temperature correction amounts. For example, a decrease of 0.1 dL / g in intrinsic viscosity (within a certain range) corresponds to a decrease of 2-3℃, because this decrease means shorter molecular chains and increased melt fluidity, requiring a lower temperature to meet melting requirements; an increase of 5% in filler ratio increases temperature by 1-2℃, because fillers increase melt viscosity and thermal conductivity, requiring higher temperatures to ensure mixing and molding quality; different additives have different temperature correction amounts, plasticizers may lower the temperature by 1-3℃, while some reinforcing additives require an increase of 2-4℃. When weighting the temperature correction amount, weights are assigned according to the significance of each characteristic parameter's influence on molding temperature, such as intrinsic viscosity 0.5, filler ratio 0.3, and additive type 0.2. The temperature correction amount of each parameter is multiplied by its weight and then summed to obtain the comprehensive temperature correction amount. Finally, the comprehensive temperature correction amount is added to the upper and lower limits of the base temperature range (positive addition, negative subtraction) to obtain the corrected target temperature range, i.e., the molding temperature range.

[0025] Specifically, when selecting several temperature sampling points for extrusion testing using a segmented step-size strategy, the following is included: Obtain the range span information of the basic temperature range, and determine the initial step size range based on the range span information; Collect correlation data between temperature changes and molding state changes during historical extrusion processes, and establish a temperature sensitivity evaluation index; The initial step size range is adjusted based on the temperature sensitivity evaluation index to obtain a segmented step size strategy; During the selection of temperature sampling points, the molding temperature range is non-uniformly divided based on a segmented step size strategy to obtain several temperature sampling points.

[0026] Understandably, the interval span information refers to the difference between the upper and lower limits of the molding temperature range. For example, when the molding temperature range is 250℃-270℃, the interval span is 20℃. The initial step size range is preferably 1 / 5 to 1 / 10 of the interval span. The temperature sensitivity evaluation index is used to measure the sensitivity of temperature changes to the molding state. When adjusting the initial step size range according to the temperature sensitivity evaluation index, a smaller step size is used in the temperature region with high sensitivity to improve sampling accuracy; a larger step size is used in the region with low sensitivity to reduce the number of tests. For example, if the temperature sensitivity is high in the 255℃-265℃ range, the step size in this range can be set to 2℃, while the step size is set to 4℃ in the regions with lower sensitivity, namely 250℃-255℃ and 265℃-270℃, thus forming a non-uniform segmented step size strategy. Based on this strategy, the molding temperature range can be divided to obtain several temperature sampling points, such as 250℃, 254℃, 256℃, 258℃, 260℃, 262℃, 264℃, 268℃, 270℃, etc., which provide specific temperature setting basis for subsequent extrusion tests.

[0027] Understandably, when obtaining temperature sensitivity evaluation indicators, it is necessary to collect molding state parameter data at different temperatures during the historical extrusion process, including the tensile strength, surface roughness, and thickness deviation of the strip. These data are then normalized to eliminate dimensional differences. The rate of change of molding state parameters corresponding to each temperature sampling point is calculated, which is the ratio of the change in molding state parameters to the change in temperature. The rates of change are then weighted and averaged, with the weights set according to the importance of each molding state parameter to product quality. For example, tensile strength has a weight of 0.4, surface roughness has a weight of 0.3, and thickness deviation has a weight of 0.3, resulting in a comprehensive temperature sensitivity evaluation index.

[0028] Specifically, determining the optimal molding temperature that ensures the molding state meets preset performance indicators includes: The defect parameters of the strip corresponding to each temperature sampling point are collected and the defect parameters are quantified to obtain the defect characterization value; among them, the defect parameters include surface defects, internal bubble defects and dimensional deviations. The defect characterization values ​​are comprehensively calculated to obtain the defect evaluation index corresponding to each temperature sampling point; The temperature sampling point with the best defect evaluation index is selected as the candidate optimal temperature, and local densification sampling is carried out in the neighborhood of the candidate optimal temperature according to the step size decreasing rule. Based on the local sampling results, a response relationship between temperature and defect evaluation index is constructed, and the temperature corresponding to the extreme point is determined as the optimal molding temperature based on the response relationship.

[0029] Understandably, strip defect parameters are collected through visual inspection systems, non-destructive testing equipment, or manual inspection. Surface defects (scratches, pits, blemishes, etc.) are statistically analyzed using image recognition technology to determine the number and maximum size of defects per unit area; internal bubble defects are determined using ultrasonic or X-ray inspection to determine their volume percentage and distribution density; dimensional deviations are measured using laser diameter gauges or calipers to measure the percentage deviation of the actual thickness and width from the standard value. When quantifying defect parameters, basic scores and weights are assigned to different types of defects. For example, surface defects are scored 1-5 points based on quantity and size (weight 0.4), internal bubbles are scored 1-5 points based on volume percentage (weight 0.3), and dimensional deviations are scored 1-5 points based on percentage deviation (weight 0.3). The weighted sum is then used to obtain the defect characterization value. The defect evaluation index is the reciprocal of the defect characterization value; the higher the value, the better the forming condition. After selecting the temperature sampling point with the optimal defect evaluation index, local sampling is intensified in its neighborhood (e.g., within ±5℃ range) using a step-decreasing rule (e.g., the original step size is 2℃, decreasing to 1℃, 0.5℃) to capture the changing trend of the defect evaluation index. Based on locally sampled temperature-defect evaluation index data, a response relationship model is constructed using quadratic curve fitting or interpolation algorithms. The extreme points are then solved, and the corresponding temperatures are the optimal molding temperatures that enable the molding state to meet preset performance indicators (such as the defect evaluation index reaching or exceeding a set threshold).

[0030] Specifically, when collecting the moisture content parameter of PET raw materials and determining whether the moisture content parameter exceeds the moisture content parameter threshold, the following steps are included: The moisture content parameter of PET raw material is obtained by online detection, and the moisture content parameter is filtered to obtain the target moisture content parameter; The target moisture content parameter is compared with the moisture content parameter threshold, and a moisture deviation index is constructed by combining the rate of change of moisture content. The defect risk level is determined based on the moisture deviation index to characterize the trend of bubble defect occurrence; When the defect risk level exceeds the preset threshold, the abnormal moisture content judgment result is output and the temperature compensation calculation is triggered.

[0031] Understandably, online detection can employ near-infrared moisture meters or microwave moisture meters to continuously collect real-time moisture content data of PET raw materials before extrusion, with a sampling frequency of no less than 1 time / second. Filtering processes utilize moving average filtering or Kalman filtering algorithms to remove high-frequency noise and transient interference, resulting in a smooth and stable target moisture content parameter. The moisture content parameter threshold is set according to the raw material type and process requirements; for example, it is typically set at 0.05% for virgin materials and can be relaxed to 0.1% for recycled materials. The formula for calculating the moisture deviation index is: Moisture Deviation = (Target Moisture Content Parameter - Moisture Content Parameter Threshold) / Moisture Content Parameter Threshold × 100% + k × Moisture Content Change Rate, where k is the rate influence coefficient, calibrated based on historical data, used to reflect the aggravating effect of the rate of moisture content change on defect risk. Defect risk levels are divided into three levels: low, medium, and high, corresponding to different ranges of the moisture deviation index; for example, deviation < 5% is low risk, 5%-15% is medium risk, and > 15% is high risk. When the defect risk level reaches medium risk or above (i.e., exceeds the preset low risk level threshold), the moisture content is determined to be abnormal, and the calculation process of the first temperature compensation amount needs to be initiated.

[0032] Specifically, determining the first temperature compensation amount based on the moisture content parameter includes: Extract the moisture deviation intensity parameter corresponding to the moisture deviation index; Calculate the effective moisture content in a unit mass of PET raw material based on the moisture deviation strength parameter; Calculate the amount of thermal disturbance generated by water vaporization based on the effective moisture content; Determine the temperature compensation base value based on the amount of thermal disturbance; The temperature compensation base value is corrected based on the rate of change of moisture content to obtain the temperature compensation amount, and the temperature compensation amount is used as the first temperature compensation amount.

[0033] Understandably, the moisture deviation intensity parameter can be quantified using a moisture deviation index. For example, the absolute value of the moisture deviation index can be used as the base value for the deviation intensity; the greater the deviation, the higher the deviation intensity parameter. The formula for calculating the effective moisture content is: Effective Moisture Content = PET Raw Material Mass × (Target Moisture Content Parameter - Moisture Content Parameter Threshold), where the PET raw material mass can be obtained from the metering data of the feeding system of the extrusion molding device. The thermal disturbance generated by moisture vaporization is related to the effective moisture content and the latent heat of vaporization of water. The calculation formula is: Thermal Disturbance = Effective Moisture Content × Latent Heat of Vaporization of Water (approximately 2260 kJ / kg). This thermal disturbance represents the heat absorbed by moisture evaporation, which leads to a decrease in melt temperature, thus requiring compensation by increasing the temperature. The temperature compensation base value is calculated based on the ratio of thermal disturbance to the heat capacity of the extrusion system, i.e., Temperature Compensation Base Value = Thermal Disturbance / (PET Raw Material Mass × PET Specific Heat Capacity), where the PET specific heat capacity is approximately 1.3-1.5 kJ / (kg·℃). Considering the impact of the rate of change in moisture content, when the moisture content rises rapidly, the rate of moisture vaporization accelerates, and the thermal disturbance becomes more severe. Therefore, a correction factor greater than 1 needs to be multiplied from the temperature compensation base value. The temperature compensation amount obtained after the above calculation and correction is the first temperature compensation amount, which is used to offset the impact of thermal disturbance caused by abnormal moisture content on the molding temperature.

[0034] Specifically, when correcting the temperature compensation baseline based on the rate of change in moisture content to obtain the temperature compensation amount, the following steps are included: The rate of change of moisture content is compared with the first rate of change of moisture content and the second rate of change of moisture content. The temperature correction coefficient of the temperature compensation base value is determined based on the comparison result. The first rate of change of moisture content is less than the second rate of change of moisture content. When the rate of change of moisture content is less than or equal to the first rate of change of moisture content, the temperature correction factor is determined to be the first temperature correction factor. When the rate of change of moisture content is greater than the first rate of change of moisture content and less than or equal to the second rate of change of moisture content, the temperature correction factor is determined to be the second temperature correction factor. When the rate of change of moisture content is greater than the rate of change of the second moisture content, the temperature correction factor is determined to be the third temperature correction factor. Multiply the temperature compensation base value by the temperature correction factor to obtain the temperature compensation amount.

[0035] Understandably, the first and second moisture content change rates are threshold values ​​set according to process requirements to differentiate the urgency of moisture content changes. For example, the first moisture content change rate can be set to 0.01% / min, and the second to 0.05% / min. The corresponding temperature correction coefficients are set based on the degree to which the moisture content change rate intensifies the thermal disturbance. The first temperature correction coefficient (corresponding to slow changes) is set to 1.0, meaning no additional correction is needed; the second temperature correction coefficient (corresponding to medium-speed changes) is set to 1.2 to address thermal disturbances caused by slightly faster moisture increases; and the third temperature correction coefficient (corresponding to rapid changes) is set to 1.5 to compensate for significant heat loss due to a sharp increase in moisture. For example, when the calculated temperature compensation base value is 5℃, and the moisture content change rate is 0.03% / min (between the first and second rates), selecting a second temperature correction coefficient of 1.2 would result in a final temperature compensation of 5℃ × 1.2 = 6℃. This tiered correction method can more accurately match the temperature compensation requirements under different moisture content change rates, avoiding insufficient or excessive compensation.

[0036] Specifically, determining the second temperature compensation amount based on operating status parameters includes: The operating parameters are analyzed to obtain the screw speed, barrel pressure and material flow fluctuation of the extrusion molding unit. The uniformity index of the extrusion molding device is calculated based on screw speed, barrel pressure and material flow fluctuation amplitude. Collect screw torque and melt viscosity data, and calculate the shear energy matching difference; The temperature change rate of each heating section of the barrel and the die head is collected, the temperature response curve is fitted, and the thermal inertia correction is calculated. Collect information on changes in cooling water temperature and calculate the cooling adjustment amount; After multiplying the material flow uniformity index, shear energy matching difference, thermal inertia correction amount, and cooling adjustment amount by the corresponding temperature correction direction factor, the values ​​are weighted and summed according to their respective weights to obtain the comprehensive temperature correction amount, which is then used as the second temperature compensation amount.

[0037] Understandably, the operating status parameters encompass key physical quantities reflecting the dynamic operation of the equipment during the extrusion molding process. In their analysis, screw speed is acquired in real-time via an encoder, measured in r / min; barrel pressure is monitored at multiple points in the melting and homogenizing sections using pressure sensors, measured in MPa; and the material flow fluctuation amplitude is obtained by calculating the ratio of the standard deviation to the average flow rate per unit time using a flow sensor installed at the die outlet. The material flow uniformity index is calculated using a weighted composite method, with the formula: Material flow uniformity index = 0.4 × (1 - screw speed fluctuation coefficient) + 0.3 × (1 - barrel pressure fluctuation coefficient) + 0.3 × (1 - material flow fluctuation amplitude), where each fluctuation coefficient is the ratio of the standard deviation of the corresponding parameter to the set value. The closer the index is to 1, the more uniform the material flow. The shear energy matching difference is calculated by comparing the product of the measured screw torque (N·m) and the melt viscosity (Pa·s) with the theoretical shear energy calculated based on standard process parameters. The difference is the measured value minus the theoretical value, measured in N·m·Pa·s. Temperature response curve fitting is performed using temperature sensor data from each heating section of the barrel (e.g., feeding section, compression section, homogenization section) and the die head. A first-order inertial plus pure hysteresis model is used for fitting. The thermal inertia correction is calculated based on the time constant and hysteresis time of the curve. When the actual heating rate is slower than the theoretical value, the correction is positive; otherwise, it is negative. The unit is °C. Cooling adjustment is calculated based on the temperature difference between the cooling water inlet and outlet (unit: °C) and the flow rate (unit: L / min). This is then combined with the cooling requirements of the PET melt to convert it into a correction value for the molding temperature. If the cooling is too strong, the temperature compensation needs to be increased; otherwise, it needs to be decreased. The unit is °C. The temperature correction direction factor is set according to the influence of each parameter on the temperature. For example, when the material flow uniformity index decreases (material flow deteriorates), the temperature needs to be increased, and the direction factor is positive; when the shear energy matching difference is positive (shear energy is too high), the temperature needs to be decreased, and the direction factor is negative. The weighting is determined based on the degree of influence of each factor on the molding temperature. For example, the weight of the material flow uniformity index is 0.3, the weight of the shear energy matching difference is 0.3, the weight of the thermal inertia correction is 0.2, and the weight of the cooling adjustment is 0.2. Multiplying the above parameters by the direction factor and the weight and then summing them gives the second temperature compensation amount used to compensate for fluctuations in the equipment's operating status.

[0038] Specifically, when obtaining the optimal molding temperature based on the optimal molding temperature, the first temperature compensation amount, and the second temperature compensation amount, the following steps are included: The optimal molding temperature is added together with the first temperature compensation amount and the second temperature compensation amount to obtain the initial adjustment temperature; The initial temperature adjustment is smoothed to obtain a smooth temperature. Based on screw speed, barrel pressure and material flow fluctuation amplitude, the temperature regulation safety boundary is calculated, and the smoothing temperature is limited within the safety boundary to obtain the safe limit temperature. The safe limit temperature is used as the optimal molding temperature for the extrusion molding device, and the adjustment command is output to the temperature control system for temperature control.

[0039] Understandably, the initial temperature adjustment is obtained by directly adding the optimal molding temperature (base temperature) to the first temperature compensation (moisture content compensation) and the second temperature compensation (operating status compensation), i.e., initial temperature adjustment = optimal molding temperature + first temperature compensation + second temperature compensation. Smoothing aims to avoid drastic temperature fluctuations impacting the molding process. This is typically achieved using an exponential moving average or a limiting filter method. For example, a maximum allowable step size for temperature changes is set (e.g., ±2℃ / adjustment). If the difference between the initial temperature adjustment and the current actual temperature exceeds this step size, the adjustment is performed according to the maximum step size; otherwise, the initial temperature adjustment is used directly as the smoothing temperature. The calculation of the temperature adjustment safety boundary must comprehensively consider equipment safety and process feasibility. When the screw speed is too high, an upper temperature limit needs to be set to avoid excessive melt shearing leading to degradation; when the barrel pressure exceeds the warning value, the temperature needs to be reduced to decrease melt viscosity and prevent equipment failure due to excessive pressure; when the material flow fluctuation is too large, the temperature adjustment range needs to be narrowed to maintain stability. The safety boundary is typically set as a temperature range, such as [250℃, 280℃], with the specific value determined based on the equipment model, raw material characteristics, and product specifications. The smoothing temperature is compared to the safety boundary. If the smoothing temperature is within the boundary range, it is directly used as the safety limit temperature; if it exceeds the upper limit, the upper boundary value is used; if it is below the lower limit, the lower boundary value is used. The final determined safety limit temperature is the optimal molding temperature for the current operating conditions of the extrusion molding unit. The control system converts this temperature value into corresponding heating or cooling control commands and outputs them to the temperature control modules of each heating section of the barrel and the die head, achieving precise and adaptive adjustment of the extrusion molding temperature.

[0040] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program goods. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program goods embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0041] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program goods according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0042] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0043] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for adaptive control of PET strapping extrusion molding temperature, characterized in that, include: Collect the raw material type information corresponding to the PET packing tape to be extruded, and determine the molding temperature range based on the raw material type information; Based on the molding temperature range, several temperature sampling points are selected through a segmented step size strategy for extrusion tests to determine the optimal molding temperature that makes the molding state meet the preset performance indicators. During the extrusion process of the PET packing tape to be extruded at the optimal molding temperature, the moisture content parameter of the PET raw material is collected, and it is determined whether the moisture content parameter exceeds the moisture content parameter threshold. If so, collect the operating status parameters of the extrusion molding device, determine the first temperature compensation amount based on the moisture content parameter, and determine the second temperature compensation amount based on the operating status parameters; Based on the optimal molding temperature, the first temperature compensation amount, and the second temperature compensation amount, the optimal molding temperature is obtained, and the temperature control system of the extrusion molding device is adjusted according to the optimal molding temperature.

2. The adaptive temperature control method for PET strapping extrusion molding according to claim 1, characterized in that, When determining the molding temperature range based on the raw material type information, the following are included: The raw material type information is parsed to obtain the category attributes of the PET raw material; wherein, the category attributes include virgin material, recycled material, and combinations thereof; Obtain the basic temperature range data corresponding to the category attribute; The characteristic parameters of the PET raw material are obtained based on the raw material type information; wherein, the characteristic parameters include intrinsic viscosity, filler ratio and additive type; The base temperature range data is corrected based on the aforementioned characteristic parameters to obtain the target temperature range; The target temperature range is defined as the molding temperature range.

3. The adaptive temperature control method for PET strapping extrusion molding according to claim 2, characterized in that, When correcting the base temperature range data based on the aforementioned characteristic parameters to obtain the target temperature range, the following steps are included: The characteristic parameters are quantified to obtain corresponding parameter values; wherein, the parameter values ​​include intrinsic viscosity, filling ratio, and additive content. Based on the preset parameter-temperature mapping relationship, the temperature correction amount corresponding to each parameter value is determined respectively; The various temperature correction values ​​are weighted to obtain a comprehensive temperature correction value. Based on the baseline temperature range data and the comprehensive temperature correction amount, the upper limit and / or lower limit of the baseline temperature range are adjusted to obtain the target temperature range.

4. The adaptive temperature control method for PET strapping extrusion molding according to claim 3, characterized in that, When selecting several temperature sampling points for extrusion testing using a segmented step-size strategy, the following are included: Obtain the range span information of the basic temperature range, and determine the initial step size range based on the range span information; Collect correlation data between temperature changes and molding state changes during historical extrusion processes, and establish a temperature sensitivity evaluation index; The initial step size range is adjusted according to the temperature sensitivity evaluation index to obtain the segmented step size strategy; During the selection of temperature sampling points, the molding temperature range is non-uniformly divided based on the segmented step size strategy to obtain several temperature sampling points.

5. The adaptive temperature control method for PET strapping extrusion molding according to claim 4, characterized in that, Determining the optimal molding temperature that enables the molding state to meet preset performance indicators includes: Collect the strip defect parameters corresponding to each temperature sampling point, and quantify the defect parameters to obtain defect characterization values; wherein, the defect parameters include surface defects, internal bubble defects, and dimensional deviations; The defect characterization values ​​are comprehensively calculated to obtain the defect evaluation index corresponding to each temperature sampling point; The temperature sampling point with the best defect evaluation index is selected as the candidate optimal temperature, and local densification sampling is performed in the neighborhood of the candidate optimal temperature according to the step size decreasing rule. Based on the local sampling results, a response relationship between temperature and defect evaluation index is constructed, and the temperature corresponding to the extreme point is determined as the optimal molding temperature based on the response relationship.

6. The adaptive temperature control method for PET strapping extrusion molding according to claim 5, characterized in that, When collecting the moisture content parameter of PET raw material and determining whether the moisture content parameter exceeds the moisture content parameter threshold, the process includes: The moisture content parameter of the PET raw material is obtained by online detection, and the moisture content parameter is filtered to obtain the target moisture content parameter. The target moisture content parameter is compared with the moisture content parameter threshold, and a moisture deviation index is constructed by combining the rate of change of moisture content. The defect risk level used to characterize the trend of bubble defect occurrence is determined based on the moisture deviation index. When the defect risk level exceeds the preset level threshold, the abnormal moisture content judgment result is output and the temperature compensation calculation is triggered.

7. The adaptive temperature control method for PET strapping extrusion molding according to claim 6, characterized in that, When determining the first temperature compensation amount based on the moisture content parameter, the following is included: Extract the moisture deviation intensity parameter corresponding to the moisture deviation index; The effective moisture content in a unit mass of PET raw material is calculated based on the moisture deviation intensity parameter. Calculate the amount of thermal disturbance generated by water vaporization based on the effective moisture content; Determine the temperature compensation base value based on the thermal disturbance amount; The temperature compensation base value is corrected based on the rate of change of moisture content to obtain the temperature compensation amount, and the temperature compensation amount is used as the first temperature compensation amount.

8. The adaptive temperature control method for PET strapping extrusion molding according to claim 7, characterized in that, When correcting the temperature compensation base value based on the rate of change of moisture content to obtain the temperature compensation amount, the following steps are included: The rate of change of moisture content is compared with the first rate of change of moisture content and the second rate of change of moisture content, and the temperature correction coefficient of the temperature compensation base value is determined based on the comparison result; wherein, the first rate of change of moisture content is less than the second rate of change of moisture content. When the rate of change of moisture content is less than or equal to the rate of change of moisture content, the temperature correction coefficient is determined to be the first temperature correction coefficient. When the rate of change of moisture content is greater than the rate of change of the first moisture content and less than or equal to the rate of change of the second moisture content, the temperature correction coefficient is determined to be the second temperature correction coefficient. When the rate of change of moisture content is greater than the rate of change of the second moisture content, the temperature correction factor is determined to be the third temperature correction factor. The temperature compensation base value is multiplied by the temperature correction coefficient to obtain the temperature compensation amount.

9. The adaptive temperature control method for PET strapping extrusion molding according to claim 8, characterized in that, When determining the second temperature compensation amount based on the operating status parameters, the following are included: The operating status parameters are analyzed to obtain the screw speed, barrel pressure, and material flow fluctuation amplitude of the extrusion molding device; The material flow uniformity index of the extrusion molding device is calculated based on the screw speed, barrel pressure, and material flow fluctuation amplitude. Collect screw torque and melt viscosity data, and calculate the shear energy matching difference; The temperature change rate of each heating section of the barrel and the die head is collected, the temperature response curve is fitted, and the thermal inertia correction is calculated. Collect information on changes in cooling water temperature and calculate the cooling adjustment amount; The material flow uniformity index, shear energy matching difference, thermal inertia correction amount, and cooling adjustment amount are multiplied by the corresponding temperature correction direction factor, and then weighted and summed according to their respective weights to obtain the comprehensive temperature correction amount, which is then used as the second temperature compensation amount.

10. The adaptive control method for PET strapping extrusion molding temperature according to claim 9, characterized in that, When obtaining the optimal molding temperature based on the optimal molding temperature, the first temperature compensation amount, and the second temperature compensation amount, the following steps are included: The optimal molding temperature is added to the first temperature compensation amount and the second temperature compensation amount to obtain the preliminary adjustment temperature; The initial temperature adjustment is smoothed to obtain a smooth temperature; Based on the screw speed, barrel pressure and material flow fluctuation amplitude, the temperature regulation safety boundary is calculated, and the smoothing temperature is limited within the safety boundary to obtain the safe limit temperature. The safety limit temperature is used as the optimal molding temperature of the extrusion molding device, and an adjustment command is output to the temperature control system for temperature control.

Images