PE blow molding production abnormal propagation path analysis method

Abstract

This invention discloses a method for analyzing the propagation path of anomalies in PE blow molding production, relating to the field of production path technology. It addresses the issues of fluctuating film structural performance and unstable product quality. By reshaping the circumferential angle of the film bubble, collecting the zoned current of the air ring drive motor and the outlet pressure of the air duct in each region to assess the air duct blockage trend, and triggering a propagation analysis mechanism when a blockage trend exists, the method obtains the circumferential temperature distribution of the film bubble and constructs temperature hysteresis characteristics based on the rotation speed. It identifies areas of abnormal cooling, aligns each region by rotation, collects the birefringence intensity of the film surface to assess the structural state and identify structural anomaly nodes, constructs a propagation path from air ring anomaly to structural anomaly, verifies the consistency of the propagation path, selects air duct cleaning or air ring adjustment based on the anomaly effect, and verifies the feedback through tensile strength testing after winding. This constructs a time-series propagation chain of air ring temperature and structural performance, enabling online identification and tracing of latent anomalies.

Description

Technical Field

[0001] This invention relates to the field of production path technology, and more specifically, to a method for analyzing the propagation path of anomalies in PE blow molding production. Background Technology

[0002] In the polyethylene (PE) blow molding process, the film bubble achieves rapid shaping under the cooling effect of the air ring. The uniformity of its cooling directly determines the thickness distribution, molecular orientation state and final mechanical properties of the film. In the existing production process, the air ring structure is usually used to provide a uniform circumferential airflow, and the dynamic equilibrium of the temperature field is achieved by combining the traction and rotation of the film bubble.

[0003] The existing technology has the following shortcomings: Currently, in actual operation, there is a lack of dynamic perception and correlation analysis methods for the coupling relationship between the airflow state of the wind ring, the circumferential temperature distribution of the membrane bubble, and the evolution of molecular structure. It is difficult to identify the formation of abnormal sources and their propagation paths in a timely manner, resulting in the inability to detect and accurately locate hidden cooling anomalies in advance, which in turn causes fluctuations in the performance of the film structure and instability in product quality. Therefore, a method for analyzing the propagation path of anomalies in PE blow molding production is proposed.

[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] To overcome the aforementioned deficiencies in the prior art, embodiments of the present invention provide a method for analyzing the abnormal propagation path in PE blow molding production. This method utilizes a multi-source data fusion modeling mechanism combined with cooling hysteresis feature extraction and abnormal propagation path construction and consistency verification methods to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for analyzing the propagation path of anomalies in PE blow molding production, comprising the following steps: Step S1: During PE blow molding, the blow molding area is reshaped at different angles. The partition current of the wind ring drive motor and the air outlet pressure of the air duct are collected for each reshaped angle area. The air duct blockage trend of each reshaped angle area is evaluated by combining the partition current and the air outlet pressure. Step S2: Determine whether the propagation analysis mechanism is triggered based on the air duct blockage trend. In the propagation analysis mechanism, detect the circumferential temperature and rotation speed of the membrane bubble in the reshaping angle region and analyze the cooling hysteresis characteristics. Mark the reshaping angle region according to the cooling hysteresis characteristics. Step S3: After rotating and aligning each remodeling angle region, the birefringence intensity of the film surface in the remodeling angle region is collected. Based on the birefringence intensity of the film surface, the molecular orientation state of the remodeling angle region is evaluated and structurally abnormal nodes are identified. The propagation path is constructed by combining the marked remodeling angle regions. Step S4: Perform consistency verification on the propagation path to assess the abnormal effect category of the propagation path. Based on the abnormal effect category, select to perform air duct cleaning or air ring adjustment. After the PE film is wound up, collect the tensile strength to determine whether to record the propagation path.

[0007] In a preferred embodiment, in step S1, before the PE blow molding production starts, a polar coordinate system is constructed based on the central axis of the air ring, and the circumferential direction of the film bubble is divided into several reshaping angle regions according to a preset angle resolution. A current sensor is installed in the power supply branch of the air duct partition motor corresponding to each reshaping angle region. The partition current of the air ring drive motor is continuously sampled at a preset sampling period to form a partition current time series. Zone current refers to the motor input current required to drive the airflow output of the corresponding duct. Pressure sensors were installed at the outlet positions of the air ducts corresponding to each reshaping angle region to synchronously collect the outlet air pressure and obtain the outlet air pressure time series. Outlet pressure refers to the static pressure of the airflow when it is output to the outside at the end of the duct.

[0008] In a preferred embodiment, in step S1, a moving average process is performed on the partition current time series and the outlet pressure time series to obtain the average partition current and the average outlet pressure. The maximum and minimum values ​​in the time series of zone current and outlet pressure are obtained, and the normalized zone current and normalized outlet pressure are constructed by combining the average zone current and average outlet pressure. The ratio of normalized zone current to normalized outlet pressure is used as the duct blockage trend.

[0009] In a preferred embodiment, in step S2, a trend determination threshold is set. When the airflow blockage trend in any reshaping angle region is greater than or equal to the trend determination threshold, the propagation analysis mechanism is triggered. Otherwise, the propagation analysis mechanism will not be triggered. In the propagation analysis mechanism, an array of infrared thermometers is arranged circumferentially on the outer surface of the membrane bubble. The circumferential temperature of the membrane bubble at the corresponding position of each remodeling angle region is continuously collected at a preset sampling period to form a time series of membrane bubble circumferential temperature. The circumferential temperature of a membrane bubble refers to the instantaneous temperature of the membrane bubble surface in the corresponding angular region. By using a rotary encoder installed in the membrane bubble traction system, the circumferential marker points of the membrane bubble are dynamically tracked to obtain the membrane bubble rotation angle that changes over time. The membrane bubble rotation speed refers to the angular velocity of the membrane bubble around its central axis. The rotation angle of the membrane bubble is calculated by difference to obtain the rotation speed of the membrane bubble, and a rotation speed sequence is constructed.

[0010] In a preferred embodiment, in step S2, the average value of the time series of the circumferential temperature of the membrane bubble in each remodeling angle region is calculated to obtain the average circumferential temperature of the membrane bubble, the average value of the average circumferential temperature of the membrane bubble in all remodeling angle regions is calculated to obtain the comprehensive average temperature, and the average circumferential temperature of the membrane bubble in each remodeling angle region is subtracted from the comprehensive average temperature to obtain the temperature deviation. The average rotational velocity is obtained by calculating the average value of the rotational velocity sequence. The rotational velocity of the membrane bubble at each sampling time is divided by the average rotational velocity to obtain the rotation correction coefficient. Multiply the temperature deviation by a rotation correction factor to construct the cooling hysteresis characteristic; Set a hysteresis judgment threshold. When the cooling hysteresis characteristic is greater than or equal to the hysteresis judgment threshold, the reshaping angle region is marked. Conversely, when the cooling hysteresis characteristic is less than the hysteresis determination threshold, the reshaping angle region is not marked.

[0011] In a preferred embodiment, in step S3, each reshaping angle region is rotated and aligned. Specifically, based on the reference angle marker set in the circumferential direction of the membrane bubble, each currently collected reshaping angle region is renumbered in circumferential angle order so that the current angle region is consistent with the marked reshaping angle region. Multiple equally spaced sampling points are selected as detection positions within the reshaping angle region. The transmitted light intensity at each detection position is collected by a linear polarization detection device. The transmitted light intensity after polarization light passes through the film surface is obtained. The ratio of the transmitted light intensity to the reference incident light intensity is calculated to obtain the birefringence intensity value of the film surface at the corresponding detection position. The average value of each birefringence intensity in the remodeling angle region is taken to obtain the birefringence intensity of the film surface in the remodeling angle region.

[0012] In a preferred embodiment, in step S3, if the birefringence intensity of the film surface is greater than the preset birefringence threshold of the film surface, the molecular orientation state of the remodeling angle region is determined to be a normal orientation state. Conversely, the molecular orientation state in the reshaping angle region is determined to be in an insufficient orientation state. The remodeling angle region where the molecular orientation state is insufficient is selected as the candidate abnormal region. The candidate anomalous region is matched with the marked reshaped angle region according to the angle number after rotation and alignment; when the two correspond in angular position, the reshaped angle region is identified as a structural anomalous node. By using the marked reshaped angle region as the propagation starting node and the structural anomaly node as the propagation response node, the propagation path is obtained.

[0013] In a preferred embodiment, in step S4, the molecular orientation state corresponding to each structurally abnormal node in the propagation path is selected, and it is determined whether the structurally abnormal node remains in an insufficient orientation state within a preset sampling period. When all structurally abnormal nodes are in an insufficient orientation state within a preset sampling period, the propagation path is determined to have passed the consistency check. Otherwise, it is determined that the consistency check has failed; The propagation path that passes the consistency check is classified into abnormal effect categories. The birefringence intensity of the film surface in the marked reshaping angle region in the propagation path is retrieved. When the birefringence intensity of the film surface is compared with the preset birefringence threshold, the absolute value of the difference is obtained to obtain the birefringence deviation. The birefringence deviation is compared with the preset birefringence deviation threshold. When the birefringence deviation exceeds the preset birefringence deviation threshold, the abnormal effect category is determined to be a significant structural anomaly. When the birefringence deviation is less than or equal to the preset birefringence deviation threshold, the abnormal effect is classified as a general structural abnormality.

[0014] In a preferred embodiment, in step S4, when the abnormal effect category is significant structural abnormality, duct cleaning is performed; when the abnormal effect category is general structural abnormality, air ring adjustment is performed. After the PE film is wound up, the tensile strength of the remodeling angle region corresponding to the structurally abnormal nodes in the propagation path is collected by an online tensile testing device after winding, and the tensile strength is compared with a preset tensile strength threshold. When the tensile strength is lower than the preset tensile strength threshold, the propagation path will be recorded in the propagation path record library. Conversely, the transmission path is not recorded.

[0015] The technical effects and advantages of this invention are as follows: This invention reshapes the circumferential angle of the membrane bubble, collects the zoned current of the wind ring drive motor and the outlet pressure of the wind duct corresponding to each angle region to assess the wind duct blockage trend. When a blockage trend is detected, a propagation analysis mechanism is triggered to obtain the circumferential temperature distribution of the membrane bubble and construct temperature hysteresis characteristics based on the membrane bubble rotation speed to identify abnormal cooling areas. Furthermore, each reshaped angle region is rotated and aligned, and the birefringence intensity of the membrane surface is collected to assess the structural evolution state and identify structural anomaly nodes. Based on this, a propagation path from wind ring anomaly to structural anomaly is constructed. Finally, the consistency of the propagation path is checked to determine the effectiveness of anomaly propagation, and wind duct cleaning or wind ring zone adjustment is selected according to the anomaly effect category. Simultaneously, tensile strength testing is used to verify and provide feedback on the path analysis results after winding. By constructing a time-series propagation chain of wind ring—temperature—structure—performance, online identification and tracing of latent anomalies are achieved. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the implementation of the method for analyzing the propagation path of anomalies in PE blow molding production according to the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the steps of a method for analyzing the propagation path of anomalies in PE blow molding production according to the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This invention reshapes the circumferential angle of the membrane bubble and collects the zoned current of the wind ring drive motor and the outlet pressure of the wind duct corresponding to each angle region to assess the wind duct blockage trend. When a blockage trend is determined, a propagation analysis mechanism is triggered to obtain the circumferential temperature distribution of the membrane bubble and construct temperature hysteresis characteristics based on the membrane bubble rotation speed to identify abnormal cooling areas. Furthermore, each reshaped angle region is rotated and aligned, and the birefringence intensity of the membrane surface is collected to assess the structural evolution state and identify structural anomaly nodes. Based on this, a propagation path from wind ring anomaly to structural anomaly is constructed. Finally, the consistency of the propagation path is checked to determine the effectiveness of anomaly propagation, and wind duct cleaning or wind ring zone adjustment is selected according to the anomaly effect category. Simultaneously, the path analysis results are verified and feedback is provided through tensile strength testing after winding.

[0020] Example 1, as Figures 1 to 2 As shown, a method for analyzing the propagation path of anomalies in PE blow molding production includes the following steps: Step S1: During PE blow molding, the blow molding area is reshaped at different angles. The partition current of the wind ring drive motor and the air outlet pressure of the air duct are collected for each reshaped angle area. The air duct blockage trend of each reshaped angle area is evaluated by combining the partition current and the air outlet pressure. Step S2: Determine whether the propagation analysis mechanism is triggered based on the air duct blockage trend. In the propagation analysis mechanism, detect the circumferential temperature and rotation speed of the membrane bubble in the reshaping angle region and analyze the cooling hysteresis characteristics. Mark the reshaping angle region according to the cooling hysteresis characteristics. Step S3: After rotating and aligning each remodeling angle region, the birefringence intensity of the film surface in the remodeling angle region is collected. Based on the birefringence intensity of the film surface, the molecular orientation state of the remodeling angle region is evaluated and structurally abnormal nodes are identified. The propagation path is constructed by combining the marked remodeling angle regions. Step S4: Perform consistency verification on the propagation path to assess the abnormal effect category of the propagation path. Based on the abnormal effect category, select to perform air duct cleaning or air ring adjustment. After the PE film is wound up, collect the tensile strength to determine whether to record the propagation path.

[0021] The specific implementation is as follows: In step S1, before the PE blow molding production run, the blow molding area is subjected to angle reshaping treatment to establish an angle discrete space that can be used for zonal evaluation.

[0022] Specifically, a polar coordinate system is constructed based on the central axis of the air ring, and the circumferential direction of the membrane bubble is divided into several reshaping angle regions according to a preset angular resolution. Each reshaping angle region corresponds to a physical partition air outlet unit of the air ring. The purpose of angle reshaping is to discretize the original continuous circumferential flow field into independently analyzable spatial units, so as to realize the partitioned evaluation of the air duct state.

[0023] Among them, the angular resolution is determined by the size of the wind ring structure and the detection accuracy requirements. The smaller the value, the more refined the angle division, the stronger the ability to characterize local blockage features, and the corresponding increase in data acquisition intensity.

[0024] After the angle reshaping process is completed, the operating parameters are collected and processed for each reshaping angle region. Specifically, current sensors are installed in the power supply branch of the duct section motor corresponding to each reshaping angle region, and the section current of the air ring drive motor is continuously sampled at a preset sampling period to form a section current time series.

[0025] Zone current refers to the motor input current required to drive the airflow output of the corresponding duct. It characterizes the duct drive load state. The larger the value, the greater the airflow resistance in the corresponding duct area and the greater the possibility of potential blockage.

[0026] It should be noted that the duct zone motor refers to the actuator motor that drives the air outlet unit of each independent duct zone of the air ring; the current sensor refers to the current detection device installed in the power supply branch of the duct zone motor, which is used to collect the motor input current signal in real time; and the air ring drive motor refers to the power device used to drive the airflow output of the entire air ring or its zones.

[0027] Meanwhile, pressure sensors are installed at the air duct outlet positions corresponding to each reshaping angle region to synchronously collect the air outlet pressure and obtain the air outlet pressure time series.

[0028] Outlet pressure refers to the static pressure of airflow at the end of the duct when it is output to the outside. It represents the airflow output capacity. The smaller the value, the higher the degree of airflow obstruction and the greater the possibility of dust accumulation or structural blockage in the duct.

[0029] Based on the time series of zone current and outlet air pressure, the duct blockage trend in each reshaping angle region is evaluated. Specifically, a moving average is first applied to the time series of zone current and outlet air pressure to obtain the average zone current and average outlet air pressure, as expressed below: ; in, It is the average zone current. It is the average outlet air pressure. It is a partitioned current time series. It is a time series of air outlet pressure. It is the sampling time. It is the sampling time index value. It represents the total number of sampling times.

[0030] Average zone current is used to eliminate the impact of instantaneous fluctuations on load assessment; a higher value indicates a higher continuous load. Average outlet pressure is used to characterize the ability to output stable airflow; a lower value indicates insufficient continuous airflow.

[0031] Furthermore, the maximum and minimum values ​​of the zone current time series and the outlet air pressure time series are obtained, and combined with the average zone current and the average outlet air pressure, normalized zone current and normalized outlet air pressure are constructed: ; in, and These are the normalized zone current and the normalized outlet pressure, respectively. It is the average zone current. It is the average outlet air pressure. and These are the maximum and minimum values ​​in the partitioned current time series, respectively. and These are the maximum and minimum values ​​in the time series of air outlet pressure, respectively.

[0032] The ratio of normalized zone current to normalized outlet pressure is used as the duct blockage trend. The duct blockage trend is the wind power matching ratio, which represents the matching relationship between the drive load and the output capacity. The larger the value, the higher the drive current consumed at a relatively low outlet pressure, reflecting the flow obstruction phenomenon inside the duct, that is, the energy consumption corresponding to the unit output capacity is abnormally high, thus indicating that the duct blockage trend is enhanced. The smaller the value, the higher the drive efficiency and the smooth duct.

[0033] Through the above processing, a quantitative assessment of the airflow blockage trend in each reshaping angle region is achieved, providing a unified and quantifiable data foundation for subsequent abnormal propagation path analysis and control strategy generation.

[0034] In step S2, based on the airflow blockage trend in each reshaping angle region, a propagation analysis mechanism is executed to trigger a judgment process.

[0035] Specifically, a trend determination threshold is set, which is determined based on the statistical distribution of the duct blockage trend in each reshaping angle region under historical normal operating conditions, such as the sum of the mean and standard deviation of the duct blockage trend in each reshaping angle region under historical normal operating conditions.

[0036] When the airflow blockage trend in any reshaped angle region is greater than or equal to the trend determination threshold, the propagation analysis mechanism is triggered; otherwise, the propagation analysis mechanism is not triggered, and the normal monitoring state described in step S1 is maintained.

[0037] In the propagation analysis mechanism, synchronous detection and processing of the circumferential temperature and rotational speed of the membrane bubble are performed in each remodeling angle region. Specifically, an array of infrared thermometers is deployed circumferentially on the outer surface of the membrane bubble, and the circumferential temperature of the membrane bubble at the corresponding position in each remodeling angle region is continuously collected at a preset sampling period to form a time series of membrane bubble circumferential temperature.

[0038] The circumferential temperature of a membrane bubble refers to the instantaneous temperature of the membrane bubble surface in the corresponding angular region, which characterizes the local cooling state. The larger the value, the more insufficient the heat dissipation and the greater the degree of cooling lag in that region.

[0039] Meanwhile, by using a rotary encoder installed in the membrane bubble traction system, the circumferential marker points of the membrane bubble are dynamically tracked to obtain the membrane bubble rotation angle that changes over time. The membrane bubble rotation speed refers to the angular velocity of the membrane bubble around its central axis, which characterizes the material migration rate of the membrane bubble in the circumferential direction. The larger the value, the shorter the cooling path that the same material experiences per unit time, which enhances the local temperature homogenization.

[0040] It should be noted that the infrared temperature sensor array refers to a detection system composed of multiple non-contact temperature detection units arranged circumferentially along the bubble. Each sensor is arranged according to the reshaping angle region to synchronously collect the surface temperature of the bubble at different angle positions. The bubble traction system refers to a mechanical structure set downstream of the blow molding production line for stretching, stabilizing, and conveying the bubble. The rotary encoder refers to an angular displacement detection device installed on the bubble traction system or the bubble surface marking point tracking device to measure the change in the rotation angle of the bubble around the central axis.

[0041] The rotation angle of the membrane bubble is calculated differentially to obtain the rotation velocity, and a rotation velocity sequence is constructed. After obtaining the circumferential temperature and rotation velocity of the membrane bubble, cooling hysteresis feature extraction is performed on each remodeling angle region.

[0042] Specifically, the average value of the time series of membrane bubble circumferential temperature in each remodeling angle region is calculated to obtain the average membrane bubble circumferential temperature. The average value of the average membrane bubble circumferential temperature in all remodeling angle regions is calculated to obtain the comprehensive average temperature. The temperature deviation is obtained by subtracting the comprehensive average temperature from the average membrane bubble circumferential temperature in each remodeling angle region. Temperature deviation is used to characterize the degree of deviation of local temperature from the overall average level. The larger the value, the more abnormal the temperature rise in that area and the more obvious the insufficient cooling.

[0043] The average rotational speed is obtained by further calculating the average value of the rotational speed sequence. The rotational speed of the membrane bubble at each sampling time is divided by the average rotational speed to obtain the rotation correction coefficient.

[0044] The rotation correction factor is used to characterize the ability of rotation speed to regulate temperature distribution. The larger the value, the lower the current rotation speed is than the average level, making it difficult for local temperature to be homogenized through circumferential motion.

[0045] The cooling hysteresis characteristic is constructed by multiplying the temperature deviation by the rotation correction factor. The cooling hysteresis characteristic reflects the coupling effect between temperature anomalies and insufficient rotation adjustment. The larger the value, the more significant the cooling hysteresis in the reshaping angle region, and the higher the potential defect risk.

[0046] The reshaping angle region is marked based on the cooling hysteresis characteristics. Specifically, a hysteresis judgment threshold is set. When the cooling hysteresis characteristic is greater than or equal to the hysteresis judgment threshold, it indicates that the cooling hysteresis of the corresponding reshaping angle region is abnormal, and it is marked. Conversely, when the cooling hysteresis characteristic is less than the hysteresis judgment threshold, it indicates that the cooling hysteresis of the corresponding reshaping angle region is normal, and it is not marked.

[0047] It should be noted that the hysteresis judgment threshold is a quantitative standard used to determine whether the cooling hysteresis characteristics are abnormal, and it is statistically determined based on historical normal operating data. Specifically, within a historical time window during which the equipment operates stably and without quality defects, cooling hysteresis characteristics of each reshaping angle region are collected to form a historical hysteresis characteristic sample set. The mean and standard deviation of the historical hysteresis characteristic sample set are calculated, and the sum of the mean and standard deviation is used as the hysteresis judgment threshold.

[0048] The labeling results are used to indicate the spatial distribution of areas with uneven cooling, providing a basis for subsequent analysis of abnormal propagation paths and optimization of control strategies.

[0049] In step S3, each reshaping angle region is rotated and aligned. Specifically, a reference angle mark is set in the circumferential direction of the membrane bubble. When collecting the birefringence intensity of the membrane surface, the current position corresponding to the reference angle mark is used as the starting angle of the circumference. Each reshaping angle region currently collected is renumbered according to the circumferential angle order, so that the current angle region corresponding to the birefringence intensity of the membrane surface is consistent with the reshaping angle region marked in step S2, thus completing the rotation alignment.

[0050] An online polarization detection device deployed on the outer periphery of the membrane bubble is used to collect the birefringence intensity of the membrane surface in each reshaping angle region. Multiple equally spaced sampling points are selected as detection positions within the reshaping angle region. The detection positions can be obtained by dividing the membrane bubble circumference into equal arc lengths.

[0051] The transmitted light intensity at each detection position is collected by a linear polarization detection device. The transmitted light intensity after the polarized light passes through the film surface is obtained. The ratio of the transmitted light intensity to the reference incident light intensity is calculated to obtain the birefringence intensity value of the film surface at the corresponding detection position.

[0052] It should be explained that the reference angle mark is used to provide a uniform angular reference starting point in the circumferential direction during the rotation of the membrane bubble, and can be set according to the identification method of the detection device or the identifiable features of the membrane bubble surface; the linear polarization detection device is an online detection device that detects the optical anisotropy of the membrane surface based on the principle of polarization optics; the reference incident light intensity can be set according to the device calibration curve or the results of periodic calibration.

[0053] The average value of each birefringence intensity in the remodeling angle region is used to obtain the birefringence intensity of the film surface in the remodeling angle region. It reflects the degree of orientation of the molecular chains in the stretching direction in the remodeling angle region. The larger the value, the more regular the molecular arrangement and the higher the degree of orientation. The smaller the value, the looser the molecular arrangement and the insufficient orientation. The molecular orientation state in the remodeling angle region is evaluated by comparing the birefringence intensity of the film surface with a preset birefringence threshold. If the birefringence intensity of the film surface is greater than the preset birefringence threshold, the molecular orientation state in the remodeling angle region is determined to be a normal orientation state. Conversely, the molecular orientation state in the reshaping angle region is determined to be in an insufficient orientation state. The remodeling angle region where the molecular orientation state is insufficient is selected as the candidate abnormal region. The candidate anomalous region is matched with the marked reshaped angle region according to the angle number after rotation and alignment; when the two correspond in angular position, the reshaped angle region is identified as a structural anomalous node. Based on structural anomaly nodes and marked remodeling angle regions, a propagation path from cooling anomalies to structural anomalies is established. Specifically, the marked remodeling angle region is used as the propagation initiation node, and the structural anomaly node as the propagation response node. This propagation path reflects the conduction relationship of molecular orientation degradation caused by cooling hysteresis within the corresponding angle region of the membrane bubble.

[0054] It should be noted that the preset birefringence threshold can be set based on the statistical results of the birefringence intensity of historical qualified products.

[0055] In step S4, the molecular orientation state corresponding to each structurally abnormal node in the propagation path is selected, and it is determined whether the structurally abnormal node remains in an insufficient orientation state within the preset sampling period. When all structurally abnormal nodes are in an insufficient orientation state within a preset sampling period, the propagation path is determined to have passed the consistency check. Otherwise, it is determined that the consistency check has failed.

[0056] It should be explained that the preset sampling period can be set according to the sampling frequency of the production line, the rotation period of the membrane bubble, and the duration of orientation fluctuations in historical stable production data.

[0057] Propagation paths that are determined to fail the consistency check are removed.

[0058] The propagation paths that pass the consistency check are classified into abnormal effect categories. Specifically, the birefringence intensity of the film surface in the marked reshaping angle region in the propagation path is retrieved. The absolute value of the difference between the birefringence intensity and the preset birefringence threshold is taken to obtain the birefringence deviation. The birefringence deviation is then compared with the preset birefringence deviation threshold. When the birefringence deviation exceeds the preset birefringence deviation threshold, the abnormal effect category is determined to be a significant structural anomaly. When the birefringence deviation is less than or equal to the preset birefringence deviation threshold, the abnormal effect is classified as a general structural abnormality. When the abnormal effect category is significant structural abnormality, select to perform air duct cleaning treatment. Specifically, perform cleaning operation on the air duct corresponding to the marked reshaping angle area that serves as the propagation starting node in the propagation path, in order to remove the dust or blockage in the area and restore the airflow and wind speed level of the area. When the abnormal effect category is general structural abnormality, select to perform air ring adjustment processing. Specifically, perform air ring air volume distribution or air outlet parameter adjustment on the reshaping angle area corresponding to the structural abnormality node in the propagation path to improve local cooling uniformity. After the PE film is wound up, the tensile strength of the remodeling angle region corresponding to the structurally abnormal nodes in the propagation path is collected by an online tensile testing device after winding. The tensile strength is compared with a preset tensile strength threshold to determine whether the propagation path should be recorded. When the tensile strength is lower than the preset tensile strength threshold, the propagation path will be recorded in the propagation path record library. Conversely, the transmission path is not recorded.

[0059] It should be noted that the preset birefringence deviation threshold is used to distinguish the severity of structural anomalies, and its value can be set according to the statistical distribution of the deviation of film surface birefringence intensity in historical qualified products and abnormal products; the preset tensile strength threshold can be set according to the statistical distribution of tensile strength of historical qualified products and quality control specifications; the online tensile testing device is an online mechanical property testing device installed after the winding station; the propagation path record library is a data storage unit used to store abnormal propagation path information that has passed consistency verification and performance verification.

[0060] This step filters out invalid propagation paths through consistency checks to prevent misjudged paths from entering the control loop. At the same time, by matching the degree of anomaly with two types of treatment strategies—duct cleaning and air ring adjustment—targeted intervention for different anomaly mechanisms is achieved, improving the accuracy and efficiency of cooling control. Furthermore, the propagation path is verified and screened by combining the tensile strength after winding, making the anomaly propagation chain verifiable and traceable, thereby achieving closed-loop control from process identification to result verification.

[0061] Finally, it should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0062] 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 limitation, 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 said element.

[0063] In this document, the singular forms “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that terms such as “comprising / including” or “having” specify the presence of the stated features, integrals, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integrals, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0064] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0065] The above description of the disclosed embodiments will enable those skilled in the art to make or use various modifications to these embodiments. It will be readily apparent to those skilled in the art that the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for analyzing the propagation path of anomalies in PE blow molding production, characterized in that: Includes the following steps: Step S1: During PE blow molding, the blow molding area is reshaped at different angles. The partition current of the wind ring drive motor and the air outlet pressure of the air duct are collected for each reshaped angle area. The air duct blockage trend of each reshaped angle area is evaluated by combining the partition current and the air outlet pressure. Step S2: Determine whether the propagation analysis mechanism is triggered based on the air duct blockage trend. In the propagation analysis mechanism, detect the circumferential temperature and rotation speed of the membrane bubble in the reshaping angle region and analyze the cooling hysteresis characteristics. Mark the reshaping angle region according to the cooling hysteresis characteristics. Step S3: After rotating and aligning each remodeling angle region, the birefringence intensity of the film surface in the remodeling angle region is collected. Based on the birefringence intensity of the film surface, the molecular orientation state of the remodeling angle region is evaluated and structurally abnormal nodes are identified. The propagation path is constructed by combining the marked remodeling angle regions. Step S4: Perform consistency verification on the propagation path to assess the abnormal effect category of the propagation path. Based on the abnormal effect category, select to perform air duct cleaning or air ring adjustment. After the PE film is wound up, collect the tensile strength to determine whether to record the propagation path.

2. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 1, characterized in that: In step S1, before the PE blow molding production begins, a polar coordinate system is constructed based on the central axis of the air ring, and the circumferential direction of the film bubble is divided into several reshaping angle regions according to a preset angle resolution. A current sensor is installed in the power supply branch of the air duct partition motor corresponding to each reshaping angle region. The partition current of the air ring drive motor is continuously sampled at a preset sampling period to form a partition current time series. Zone current refers to the motor input current required to drive the airflow output of the corresponding duct. Pressure sensors were installed at the outlet positions of the air ducts corresponding to each reshaping angle region to synchronously collect the outlet air pressure and obtain the outlet air pressure time series. Outlet pressure refers to the static pressure of the airflow when it is output to the outside at the end of the duct.

3. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 2, characterized in that: In step S1, a moving average process is performed on the partition current time series and the outlet air pressure time series to obtain the average partition current and the average outlet air pressure. The maximum and minimum values ​​in the time series of zone current and outlet pressure are obtained, and the normalized zone current and normalized outlet pressure are constructed by combining the average zone current and average outlet pressure. The ratio of normalized zone current to normalized outlet pressure is used as the duct blockage trend.

4. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 3, characterized in that: In step S2, a trend determination threshold is set. When the airflow blockage trend in any reshaping angle region is greater than or equal to the trend determination threshold, the propagation analysis mechanism is triggered. Otherwise, the propagation analysis mechanism will not be triggered. In the propagation analysis mechanism, an array of infrared thermometers is arranged circumferentially on the outer surface of the membrane bubble. The circumferential temperature of the membrane bubble at the corresponding position of each remodeling angle region is continuously collected at a preset sampling period to form a time series of membrane bubble circumferential temperature. The circumferential temperature of a membrane bubble refers to the instantaneous temperature of the membrane bubble surface in the corresponding angular region. By using a rotary encoder installed in the membrane bubble traction system, the circumferential marker points of the membrane bubble are dynamically tracked to obtain the membrane bubble rotation angle that changes over time. The membrane bubble rotation speed refers to the angular velocity of the membrane bubble around its central axis. The rotation angle of the membrane bubble is calculated by difference to obtain the rotation speed of the membrane bubble, and a rotation speed sequence is constructed.

5. The method for analyzing the propagation path of abnormalities in PE blow molding production according to claim 4, characterized in that: In step S2, the average value of the time series of membrane bubble circumferential temperature in each remodeling angle region is calculated to obtain the average membrane bubble circumferential temperature. The average value of the average membrane bubble circumferential temperature in all remodeling angle regions is calculated to obtain the comprehensive average temperature. The average membrane bubble circumferential temperature in each remodeling angle region is subtracted from the comprehensive average temperature to obtain the temperature deviation. The average rotational velocity is obtained by calculating the average value of the rotational velocity sequence. The rotational velocity of the membrane bubble at each sampling time is divided by the average rotational velocity to obtain the rotation correction coefficient. Multiply the temperature deviation by a rotation correction factor to construct the cooling hysteresis characteristic; Set a hysteresis judgment threshold. When the cooling hysteresis characteristic is greater than or equal to the hysteresis judgment threshold, the reshaping angle region is marked. Conversely, when the cooling hysteresis characteristic is less than the hysteresis determination threshold, the reshaping angle region is not marked.

6. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 1, characterized in that: In step S3, each reshaping angle region is rotated and aligned. Specifically, based on the reference angle marker set in the circumferential direction of the membrane bubble, each currently acquired reshaping angle region is renumbered in circumferential angle order so that the current angle region is consistent with the marked reshaping angle region. Multiple equally spaced sampling points are selected as detection positions within the reshaping angle region. The transmitted light intensity at each detection position is collected by a linear polarization detection device. The transmitted light intensity after polarization light passes through the film surface is obtained. The ratio of the transmitted light intensity to the reference incident light intensity is calculated to obtain the birefringence intensity value of the film surface at the corresponding detection position. The average value of each birefringence intensity in the remodeling angle region is taken to obtain the birefringence intensity of the film surface in the remodeling angle region.

7. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 6, characterized in that: In step S3, if the birefringence intensity of the film surface is greater than the preset birefringence threshold, the molecular orientation state of the remodeling angle region is determined to be a normal orientation state. Conversely, the molecular orientation state in the reshaping angle region is determined to be in an insufficient orientation state. The remodeling angle region where the molecular orientation state is insufficient is selected as the candidate abnormal region. The candidate anomalous region is matched with the marked reshaped angle region according to the angle number after rotation and alignment; when the two correspond in angular position, the reshaped angle region is identified as a structural anomalous node. By using the marked reshaped angle region as the propagation starting node and the structural anomaly node as the propagation response node, the propagation path is obtained.

8. The method for analyzing the propagation path of anomalies in PE blow molding production according to claim 7, characterized in that: In step S4, the molecular orientation state corresponding to each structurally abnormal node in the propagation path is selected, and it is determined whether the structurally abnormal node remains in an insufficient orientation state within the preset sampling period. When all structurally abnormal nodes are in an insufficient orientation state within a preset sampling period, the propagation path is determined to have passed the consistency check. Otherwise, it is determined that the consistency check has failed; The propagation path that passes the consistency check is classified into abnormal effect categories. The birefringence intensity of the film surface in the marked reshaping angle region in the propagation path is retrieved. When the birefringence intensity of the film surface is compared with the preset birefringence threshold, the absolute value of the difference is obtained to obtain the birefringence deviation. The birefringence deviation is compared with the preset birefringence deviation threshold. When the birefringence deviation exceeds the preset birefringence deviation threshold, the abnormal effect category is determined to be a significant structural anomaly. When the birefringence deviation is less than or equal to the preset birefringence deviation threshold, the abnormal effect is classified as a general structural abnormality.

9. The method for analyzing the propagation path of abnormalities in PE blow molding production according to claim 8, characterized in that: In step S4, when the abnormal effect category is significant structural abnormality, the air duct cleaning process is selected; When the abnormal effect category is general structural abnormality, select to perform air ring adjustment treatment; After the PE film is wound up, the tensile strength of the remodeling angle region corresponding to the structurally abnormal nodes in the propagation path is collected by an online tensile testing device after winding, and the tensile strength is compared with a preset tensile strength threshold. When the tensile strength is lower than the preset tensile strength threshold, the propagation path will be recorded in the propagation path record library. Conversely, the transmission path is not recorded.

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