A biaxial stretching production line anti-downtime control system and control method

Abstract

The present invention provides a biaxial stretching production line anti-downtime control system and control method, the control system comprising: a measuring module, a central processing module, a communication module, a storage module and a fault processing module; the measuring module, the storage module and the fault processing module are respectively connected to the central processing module through the communication module, wherein the measuring module comprises a plurality of detection points arranged in the biaxial stretching production line, a temperature sensor and a pressure sensor are respectively arranged at each detection point, the central processing module monitors the operating status of the biaxial stretching production line according to the temperature and pressure values ​​detected by each detection point, the biaxial stretching production line anti-downtime control system and control method of the present invention have the advantages of high precision, and can accurately identify the deviation when the production process of the biaxial stretching production line deviates, thereby preventing some minor deviations in the production process from continuing to develop and eventually causing the production line to shut down.

Description

Technical Field

[0001] The present invention relates to the technical field of film preparation, and in particular to a biaxial stretching production line anti-downtime control system and a control method. Background Art

[0002] Plastic film is the product with the largest output and the widest application in the application of plastic products. Its application field not only involves industry, but also involves daily livelihood. Traditional plastic film forming processes include bubble blowing, cast film, multi-roll calendering, laminating, etc. The mechanical properties of the films prepared by these methods are mostly determined by the mechanical properties of the material itself. With the improvement of film performance requirements in different fields, the mechanical properties of traditional films can no longer meet the use requirements of the corresponding fields, especially in the field of flexible packaging. In order to improve the mechanical and barrier properties of films and realize the high performance and functionalization of film applications, the stretching process that changes the material properties with the help of the material crystal structure has emerged. By stretching the film, the internal molecular conformation of the material can be changed at the microscopic level, effectively improving the mechanical properties and barrier properties of the film. At present, the stretching processes for films mainly include uniaxial stretching and biaxial stretching. Among them, uniaxial stretching films only induce material crystallization in one direction, while insufficient crystallization or non-crystallization in the other direction will cause the material strength in that direction to drop significantly. Therefore, the biaxial stretching process can produce high-performance films with more uniform performance.

[0003] The basic principle of biaxial stretching technology is: after the polymer raw material is heated and melted through an extruder to be extruded into a thick sheet, it is stretched longitudinally and transversely by a certain multiple in the appropriate temperature range above the glass transition temperature and below the melting point (in a high elastic state) through a longitudinal stretching machine and a transverse stretching machine under the action of external force, so that the molecular chain or crystal plane is reoriented and arranged in an orderly manner in the direction parallel to the film plane, thereby adjusting and improving the aggregate structure of the polymer, and then heat-setting is performed under tension to fix the oriented macromolecular structure, and finally a permanent transparent film can be obtained after cooling and subsequent treatment. Therefore, after biaxial stretching, the tensile strength and elastic modulus of the plastic film are significantly increased, and the mechanical strength is significantly improved. In addition, the heat resistance, cold resistance, transparency, glossiness, air tightness, moisture resistance and other properties can also be improved, and it has a wide range of uses. At present, the main polymer materials used for the production of biaxially stretched films are: polypropylene, polyester, polystyrene, polyamide, polyvinyl alcohol, EVOH, polyvinylidene chloride, polyethylene, etc.

[0004] At present, the main forming methods of biaxially oriented films are flat film method and tube film method. The tube film method has low equipment investment and small footprint, but the product thickness accuracy is poor and the production efficiency is low. It is limited to the production of special products such as polypropylene heat shrink film and cigarette packaging film; the film produced by the flat film method has good quality, high thickness accuracy and high production efficiency. It is currently the most widely used biaxially oriented film preparation process. The flat film method can be further divided into two methods: step-by-step biaxial stretching and synchronous biaxial stretching. The step-by-step biaxial stretching method has mature equipment and high line speed, and is currently the mainstream of the flat film method; while the same-fabric biaxial stretching method is expensive due to the equipment, immature production process, and difficult process control. The production line is prone to electrical failures, mechanical failures, tension control problems, temperature control problems, pressure problems, etc. during the production process, resulting in frequent downtime (i.e., abnormalities and stoppages) due to various failures. In severe cases, it may even damage the production equipment and cause a large amount of waste of raw materials, which limits production and application. However, the step-by-step biaxial stretching process has a serious disadvantage, namely, a large bow effect. The prepared film has inconsistent diagonal heat shrinkage rates. Composite packaging produced using this base film may be deformed or warped. The bow effect will cause a considerable portion of the film products produced to fail to meet the end-user's requirements. The synchronous biaxial stretching process can effectively improve the bow effect problem. The produced film has the characteristics of good quality balance and good market prospects. In addition, for polymers with high elasticity, fast crystallization speed and high crystallinity, if longitudinal stretching is performed first, the polymer will be subjected to stress-induced crystallization, which will increase the crystallization rate and cause a large amount of crystallization. The crystallized part of the film is difficult to stretch again, which can easily increase the probability of film breakage during transverse stretching, so it must be prepared using a synchronous biaxial stretching process. Therefore, the development of a synchronous biaxial stretching production line that can operate stably is one of the technical problems that technicians in this field need to solve urgently.

[0005] To this end, those skilled in the art have made improvements in many directions. In summary, they can be divided into the following two types: one is to upgrade and transform the equipment to improve the adaptability and control accuracy of the equipment. For example, Chinese patents with publication (announcement) numbers CN111216345A, CN103240870A, CN111086196B, CN102069586A, CN105542363B, CN114536727B, CN112793138A, and CN104044263B disclose a variety of methods for transforming equipment in a biaxial stretching production line; the other is to improve the biaxial stretching process, such as the Chinese patents with publication (announcement) numbers CN111216345A, CN103240870A, CN111086196B, CN102069586A, CN105542363B, CN114536727B, CN112793138A, and CN104044263B disclose a variety of methods for transforming equipment in a biaxial stretching production line; Chinese patents No. 5071240A, CN102683631B, CN102683630B, CN114228122B, and CN107672191B disclose a variety of methods for optimizing and improving the stretching process; however, the biaxial stretching production line involves a large number of devices and the problems that cause failures are complex and diverse. The effect and scope of application of this method of improving individual devices or specific film preparation processes are very limited. In addition, these two methods either require a complete replacement or modification of the equipment, which is expensive, or are only applicable to a certain type or a certain class of specific film production processes, and have a small scope of application. They cannot solve the problems existing in the synchronous biaxial stretching process.

[0006] In fact, through investigation and statistical analysis, it was found that most of the reasons for the failure and downtime of the biaxial stretching production line were due to some minor deviations in the production process that were not discovered in time, which eventually led to the production line being stuck or malfunctioning and unable to operate. For example, the temperature of the melt extrusion device was lower than the normal value, resulting in the subsequent low temperature of the casting and failure to reach the stretching temperature of the film, resulting in reduced tensile performance of the casting, and subsequent problems such as film breakage and tearing were prone to occur during the synchronous biaxial stretching process. For example, in the process of cooling the material extruded by the melt extrusion device through the cold drum, the cold drum did not suck the casting tightly due to an electrical failure, resulting in insufficient cooling of the casting and high temperature. In the subsequent synchronous biaxial stretching process, the material was prone to adhere to the equipment and could not be drawn into a film, resulting in a decrease in the uniformity of the film thickness and an increase in the haze. For example, in the synchronous biaxial stretching process, the thickness of the film was uneven and the performance was reduced due to the abnormal operation of some of the chain clips and the failure to open and clamp the casting in time. For example, the film gradually deviated during the forward movement, eventually leading to abnormal film production.

[0007] Therefore, it is of great significance to promote the promotion and development of the synchronous biaxial stretching process to provide an anti-downtime control system and control method for the biaxial stretching production line with low modification cost and wide application range, so as to timely identify these tiny deviations and prevent them from further development and causing production line downtime. Summary of the invention

[0008] The present invention designs a biaxial stretching production line anti-downtime control system and control method with low modification cost and wide application range, so as to timely identify slight deviations in the production process of the biaxial stretching production line, guide operators to correct them in time, and prevent their continuous development and cause technical problems of production line downtime.

[0009] To solve the above problems, the present invention discloses a biaxial stretching production line anti-downtime control system, comprising: a measuring module, a central processing module, a communication module, a storage module and a fault processing module; the measuring module, the storage module and the fault processing module are respectively connected to the central processing module through the communication module, wherein the measuring module comprises a plurality of detection points arranged in the biaxial stretching production line, a temperature sensor and a pressure sensor are respectively arranged at each detection point, and the central processing module monitors the operating status of the biaxial stretching production line according to the temperature and pressure values ​​detected at each detection point.

[0010] Furthermore, a plurality of detection points distributed in a spiral shape are respectively arranged on the roller-shaped devices in the biaxial stretching production line.

[0011] Further, the roller device comprises:

[0012] A central shaft, which is connected to the driving device and can rotate around its central axis under the drive of the driving device;

[0013] A roller core part, which is arranged on the periphery of the central shaft and can rotate synchronously with the central shaft;

[0014] A roller portion, which is arranged on the periphery of the roller core and can rotate synchronously with the drive of the central shaft;

[0015] A sensor receiving groove is spirally arranged on the surface of the roller core, and a temperature sensor and a pressure sensor are arranged in the sensor receiving groove to form the detection point.

[0016] Furthermore, a spiral line formed by the plurality of sensor accommodating grooves extends from one end of the roller to the other end, and a pitch of the spiral line is equal to an axial length of the roller core.

[0017] Furthermore, a detection point is respectively arranged on the clamping surface of each chain clamp in the synchronous biaxial stretching device in the biaxial stretching production line.

[0018] A method for preventing downtime of a biaxial stretching production line is disclosed, and the method is used for the above-mentioned control system. The control method comprises the following steps:

[0019] S1, debug the biaxial stretching production line, and obtain multiple temperature values ​​and multiple pressure values ​​of each detection point at different times when the biaxial stretching production line is running stably;

[0020] S2, determining the standard value of each detection point according to the temperature value and pressure value of each detection point obtained in step S1;

[0021] S3, determining a feature vector group of each detection point according to the standard value of each detection point, and storing the feature vector group in a storage module;

[0022] S4, during the daily operation of the biaxial stretching production line, the temperature and pressure values ​​of each detection point are measured in real time;

[0023] S5, calculating the simulation value of each detection point according to the temperature value and pressure value of each detection point measured in real time in step S4;

[0024] S6, comparing the simulation value of each detection point obtained in step S5 with the real-time detection value obtained in step S4, and determining whether the difference between the simulation value and the detection value of the detection point is less than or equal to a preset threshold; if so, it is considered that the detection point is operating normally; if not, it is considered that the detection point may be operating abnormally, and step S7 is continued;

[0025] S7, obtaining multiple measured values ​​of each detection point within a period of time;

[0026] S8, respectively determining the average value, maximum value and minimum value of the multiple measured values ​​of each detection point obtained in step S7;

[0027] S9, comparing the average value, maximum value and minimum value of each detection point obtained in step S8 with the standard value obtained in step S2, and then issuing a corresponding fault handling instruction according to the comparison result.

[0028] Furthermore, the step S2 includes:

[0029] S21, firstly, marking the coordinate points corresponding to all the temperature values ​​and pressure values ​​of one of the detection points obtained in step S1 in the temperature-pressure coordinate system;

[0030] S22, in the temperature-pressure coordinate system, draw a circle with the smallest radius so that 70% to 90% of the coordinate points corresponding to the detection points are located in the drawn circle;

[0031] S23, respectively calculating the average values ​​of the horizontal coordinate and the vertical coordinate of each coordinate point in the circle, and using them as the standard values ​​of the temperature and pressure of the detection point;

[0032] S24, traverse all the detection points in turn to obtain the standard value of the temperature and pressure of each detection point.

[0033] Furthermore, the step S3 includes:

[0034] S31, number each inspection point according to the order of material movement, and record the number of each inspection point as J ab , where a is the serial number of each process and b is the serial number of the inspection point of the process;

[0035] S32, in the temperature-pressure coordinate system, taking the standard value of the current detection point as the end point and taking the standard values ​​of other detection points as the starting points, drawing multiple vectors, and the obtained multiple vectors are the characteristic vector group of the current detection point;

[0036] S33, traverse all the detection points in sequence to obtain the feature vector group of each detection point.

[0037] Furthermore, the step S5 comprises:

[0038] S51, obtaining a feature vector group of each detection point stored in the storage module, and marking the temperature value and pressure value of each detection point measured in real time in step S4 in the temperature-pressure coordinate system to obtain the coordinate point of the measured value corresponding to each detection point;

[0039] S52, sequentially translating each feature vector in the feature vector group of the current detection point so that the starting point of the translated feature vector is the coordinate point of the measured value of each other detection point;

[0040] S53, obtaining the end points of each translated characteristic vector and the temperature and pressure values ​​corresponding to the end points;

[0041] S54, calculating the average value of the temperature value and the average value of the pressure value corresponding to the end point after the translation of each characteristic vector from the same process, and using them as the simulated value of the temperature and pressure from the process, and correspondingly, the coordinate point of the simulated value of the temperature and pressure in the temperature-pressure coordinate system is the simulated coordinate point from the process;

[0042] S55, obtaining the simulated coordinate points of the current detection point from each process;

[0043] S56, sequentially connecting the simulated coordinate points of the current detection point from each process to obtain a polygon;

[0044] S57, finding the center of gravity of the polygon, and the temperature and pressure values ​​corresponding to the center of gravity are the simulation values ​​of the current detection point;

[0045] S58, traverse all the detection points in sequence to obtain the simulation values ​​corresponding to all the detection points.

[0046] Furthermore, the step S9 includes:

[0047] S91, first compare the average value of the current detection point with the corresponding standard value obtained in step S2:

[0048] If |average value - standard value| ≤ 3% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 1 is 0;

[0049] If 3% of the standard value < | average value - standard value | ≤ 5% of the standard value, the process is considered to be abnormal, and the abnormality index K 1 is α 1 *|average value-standard value| / standard value;

[0050] If 5% of the standard value is less than |average value-standard value|, the process is considered to be abnormal, and the abnormality index K 1 is α 2 *|average value-standard value| / standard value;

[0051] Among them, 0.5<α 1 <α 2 <3, α 1 and α 2 The specific value of is determined through experiments;

[0052] S92, then compare the maximum value of the current detection point with the standard value obtained in step S2:

[0053] If |maximum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 2 is 0;

[0054] If 5% of the standard value is less than | maximum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K 2 β 1 *|Maximum value-standard value| / standard value;

[0055] If 8% of the standard value is less than |maximum value-standard value|, the process is considered to be abnormal, and the abnormality index K 2 β 2 *|Maximum value-standard value| / standard value;

[0056] Among them, 0<β 1 <β 2 <0.5, β 1 and β 2 The specific value of is determined through experiments;

[0057] S93, then compare the minimum value of the current detection point with the standard value obtained in step S2:

[0058] If |minimum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 3 is 0;

[0059] If 5% of the standard value is less than | minimum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K 3 For γ 1 *|minimum value-standard value| / standard value;

[0060] If 8% of the standard value is less than |minimum value - standard value|, the process is considered to be abnormal, and the abnormality index K 3 For γ 2 *|minimum value-standard value| / standard value;

[0061] Among them, 0<γ 1 <γ 2 <0.5,γ 1 and γ 2 The specific value of is determined through experiments;

[0062] S94, calculate the total abnormality index K of each detection point 总 , where the total abnormality index K 总 =K 1 +K 2 +K 3 ;

[0063] S95, the total abnormality index K of each detection point 总 Compared with the preset total abnormality index K 异常 For comparison:

[0064] If K 总 ≤K 异常 , then it is considered that the detection point is operating normally;

[0065] If K 异常 <K 总 ≤1.5*K 异常 , it is considered that the detection point is running slightly abnormally, a fault log is generated, and a fault handling instruction - abnormal reminder is issued;

[0066] If 1.5*K 异常 <K 总 ≤2*K 异常 , the detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - delayed shutdown:

[0067] If 2*K 异常 <K 总， The detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - immediate shutdown.

[0068] The anti-downtime control system and control method for the biaxial stretching production line described in the present invention have the advantages of high precision and can accurately identify deviations when deviations occur in the production process of the biaxial stretching production line, thereby preventing some minor deviations in the production process from continuing to develop and eventually causing the production line to shut down. At the same time, the anti-downtime control system and control method for the biaxial stretching production line described in the present invention also have the advantages of low modification cost and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic diagram of the module structure of the anti-downtime control system for the biaxial stretching production line of the present invention;

[0070] Figure 2 It is a schematic diagram of the biaxial stretching production line and its data detection method according to the present invention;

[0071] Figure 3 It is a schematic diagram of the structure of the roller device in the biaxial stretching production line of the present invention;

[0072] Figure 4 A schematic diagram of the distribution of detection points on the roller-shaped device of the present invention;

[0073] Figure 5 This is an example of the feature vector calculation process of the detection point of the present invention;

[0074] Figure 6 This is an example of the calculation process of the simulation value of the detection point described in the present invention.

[0075] Explanation of reference numerals: 1. roller surface portion; 2. roller core portion; 3. center axis; 4. sensor receiving groove. DETAILED DESCRIPTION

[0076] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0077] like Figures 1 to 4 As shown, a biaxial stretching production line anti-downtime control system includes: a measurement module, a central processing module, a communication module, a storage module and a fault processing module;

[0078] Wherein, the measuring module is connected to the central processing module through the communication module, so that the data detected by the measuring module can be transmitted to the central processing module through the communication module;

[0079] The storage module is connected to the central processing module through the communication module, so that the central processing module can transmit the information to be stored to the storage module through the communication module;

[0080] The fault processing module is connected to the central processing module through the communication module, so that the central processing module can transmit the fault processing instruction to the fault processing module through the communication module.

[0081] As some embodiments of the present invention, the fault handling module can be directly connected to the control center of the biaxial stretching production line. When a device fails, the control center of the biaxial stretching production line can adjust the operating status of each device in the production line according to the instructions issued by the fault handling module. In this way, the anti-downtime control system of the biaxial stretching production line has a higher degree of automation and is more intelligent.

[0082] As some other embodiments of the present invention, the biaxial stretching production line anti-downtime control system also includes a display, and the fault handling module can also be directly connected to the display, and output the instructions issued by the fault handling module through the display, and then the operator controls the operating status of each device in the production line according to the instructions issued by the fault handling module. In this way, the structure of the biaxial stretching production line anti-downtime control system can be simplified and the user's operating freedom can be improved.

[0083] Furthermore, the measuring module includes a plurality of detection points arranged in the biaxial stretching production line, and a temperature sensor and a pressure sensor are respectively arranged at each detection point.

[0084] Furthermore, the biaxial stretching production line includes: a batching and mixing device, a crystallization and drying device, a melt extrusion device, a cast sheet cooling device, a synchronous biaxial stretching device and a heat setting device.

[0085] In addition, the biaxial stretching production line also includes: a cooling device, a traction and winding device, etc.

[0086] Further, such as Figure 2 As shown, a plurality of detection points are respectively set on the devices of each process constituting the biaxial stretching production line, and each detection point is numbered.

[0087] Specifically, the detection points of each process can be numbered in sequence according to the order in which the materials advance. Preferably, the numbering format of the detection points is J ab , where a is the serial number of each process. For example, for the batching and mixing device in the first process, the value of a is 1; for the crystallization and drying device in the second process, the value of a is 2; b is the serial number of the detection point in each process. For example, if there are two detection points in the crystallization and drying device in the second process, the value of b can be set to 1 and 2 respectively. Then, the numbers of the two detection points in the crystallization and drying device in the second process will be detection point J. 21 and J 22 .

[0088] According to actual production experience, the biaxial stretching production line includes at least crystallization and drying devices, melt extrusion devices, cast sheet cooling devices, synchronous biaxial stretching devices and other processes. Therefore, the maximum value of a is ≥4.

[0089] Preferably, for the roller-shaped devices in the biaxial stretching production line, such as the quenching roller in the casting cooling device, the cooling roller in the cooling device, the winding roller in the traction and winding device, etc., multiple detection points distributed in a spiral shape are set on each roller, and a temperature sensor and a pressure sensor are set on each detection point. The detection points on each roller are numbered from one end to the other. In this way, data at different circumferential and radial positions of the roller-shaped device can be detected, laying the foundation for subsequent accurate abnormal condition judgment.

[0090] As some embodiments of the present application, the structure of the roller device in the biaxial stretching production line is as follows: Figure 3~4 As shown: Each roller device includes:

[0091] The central shaft 3 is connected to the driving device and can rotate around its central axis under the drive of the driving device;

[0092] The roller core 2 is arranged on the periphery of the central shaft 3 and can rotate synchronously with the central shaft 3;

[0093] The roller portion 1 is arranged on the periphery of the roller core 2 and can rotate synchronously with the drive of the central shaft 3;

[0094] The sensor receiving groove 4 is spirally arranged on the surface of the roller core 2, and a temperature sensor and a pressure sensor are arranged in the sensor receiving groove 4 to form the detection point.

[0095] Preferably, the surfaces of the temperature sensor and the pressure sensor are flush with the surface of the roller core 2 .

[0096] As some embodiments of the present application, the central shaft 3 and the roller core 2 are made of cemented carbide, and the roller surface portion 1 is made of elastic polymer materials, such as plastic, rubber, etc.

[0097] Preferably, the thickness ratio of the roller core portion 2 to the roller surface portion 1 in the radial direction is ≥50:1.

[0098] Preferably, a spiral line formed by the multiple sensor accommodating grooves 4 extends from one end of the roller to the other end, and the pitch of the spiral line is equal to the axial length of the roller core 2, so that the projection of the sensor accommodating grooves 4 on the end surface of the roller is a circle with uniform intervals, and the sensors in the sensor accommodating grooves 4 can detect the temperature and pressure at the detection points at different radial and circumferential positions in each roller.

[0099] As some embodiments of the present application, 8 to 20 detection points distributed in a spiral shape may be set on each roller according to the length of the roller.

[0100] In addition, for non-roller-shaped devices such as a batching and mixing device, a crystallization and drying device, a melt extrusion device, a synchronous biaxial stretching device, and a heat setting device, at least one detection point is set on each device.

[0101] As some embodiments of the present application, 1 to 2 detection points can be set in the batching and mixing device and the crystallization and drying device respectively, and temperature sensors and pressure sensors can be set at the detection points to detect the temperature and pressure of the materials therein.

[0102] Preferably, two detection points can be set inside the batching and mixing device and the crystallization and drying device respectively, one of which is located inside the batching and mixing device and the crystallization and drying device, and the other is located at the discharge port of the batching and mixing device and the crystallization and drying device.

[0103] As some embodiments of the present application, 3 to 5 detection points can be set inside the melt extrusion device and the heat setting device. For example, 2 to 3 detection points can be evenly spaced in the heat setting device, and a temperature sensor and a pressure sensor can be set at each detection point to detect the temperature and pressure at the location thereof.

[0104] Preferably, at least one detection point should be respectively set at the barrel and the extrusion head of the melt extrusion device, and a temperature sensor and a pressure sensor should be respectively set at each detection point to detect the temperature and pressure at the location thereof.

[0105] As some embodiments of the present application, a detection point is respectively set on the clamping surface of each chain clamp in the synchronous biaxial stretching device, and a temperature sensor and a pressure sensor are respectively set at each detection point to detect the temperature and pressure at the location thereof; wherein the chain clamp is the position of the synchronous biaxial stretching device for clamping the film, and the clamping surface of the chain clamp is the position where it contacts the film.

[0106] Preferably, a groove is provided on the clamping surface of the chain clamp, the temperature sensor and the pressure sensor are arranged in the groove, and then the groove is covered with an elastic polymer material, such as plastic, rubber, etc.

[0107] The detection points described in the present invention can be realized by simply modifying and adding detection points to existing production line equipment, which is low-cost and easy to implement.

[0108] As some embodiments of the present application, the anti-downtime control system for the biaxial stretching production line described in the present invention can be directly applied to the existing synchronous biaxial stretching process, and its general process is as follows: Figure 2 As shown: a prepared mixture is obtained through a batching and mixing device, and then the mixture is sent to a crystallization and drying device for drying. The dried mixture is sent to a melt extrusion device for melt extrusion. The extruded material is cooled by a casting cooling device to obtain a casting, and then stretched by a synchronous biaxial stretching device. The stretched material is heat-set by a heat-setting device, and then cooled and wound by a cooling device, a traction and winding device, etc. to obtain a film product.

[0109] Of course, the above-mentioned synchronous biaxial stretching process can also be appropriately modified. In this case, it is only necessary to add detection points to the corresponding equipment as needed.

[0110] In addition, the present invention also provides a biaxial stretching production line anti-downtime control method, the control method is used for the above-mentioned control system, and the control method comprises the steps of:

[0111] S1, debug the biaxial stretching production line, and obtain multiple temperature values ​​and multiple pressure values ​​of each detection point at different times when the biaxial stretching production line is running stably;

[0112] S2, determining the standard value of each detection point according to the temperature value and pressure value of each detection point obtained in step S1;

[0113] S3, determining a feature vector group of each detection point according to the standard value of each detection point, and storing the feature vector group in a storage module;

[0114] S4, during the daily operation of the biaxial stretching production line, the temperature and pressure values ​​of each detection point are measured in real time;

[0115] S5, calculating the simulation value of each detection point according to the temperature value and pressure value of each detection point measured in real time in step S4;

[0116] S6, comparing the simulation value of each detection point obtained in step S5 with the real-time detection value obtained in step S4, and determining whether the difference between the simulation value and the detection value of the detection point is less than or equal to a preset threshold; if so, it is considered that the detection point is operating normally; if not, it is considered that the detection point may be operating abnormally, and step S7 is continued;

[0117] S7, obtaining multiple measured values ​​of each detection point within a period of time;

[0118] S8, respectively determining the average value, maximum value and minimum value of the multiple measured values ​​of each detection point obtained in step S7;

[0119] S9, comparing the average value, maximum value and minimum value of each detection point obtained in step S8 with the standard value obtained in step S2, and then issuing a corresponding fault handling instruction according to the comparison result.

[0120] Furthermore, the time interval is set, such as automatically controlling the biaxial stretching production line to execute the above-mentioned biaxial stretching production line anti-downtime control method once every 1 minute to 5 minutes.

[0121] Specifically, in step S1, when the biaxial stretching production line is in stable operation, a plurality of temperature values ​​and a plurality of pressure values ​​of each detection point can be obtained through the measurement module at certain intervals, such as 0.1s to 1min, and stored in the storage module.

[0122] It should be noted that, in step S1, for the detection points that move in the production line, such as the detection points set on the roller device and the detection points set on the chain clamp, the detection points should be in the same position each time the measurement data is obtained.

[0123] Preferably, the measurement data is acquired at the intermediate moment when the detection point contacts the material, such as acquiring the measurement data when the detection point on the roller-shaped device moves to the center line of the contact area between the roller and the material; or acquiring the measurement data when the detection point on the chain clamp moves to the middle position of all the chain clamps that clamp the material.

[0124] As some embodiments of the present application, in step S1, 10 to 60 temperature values ​​and pressure values ​​of each detection point can be obtained at regular intervals while the biaxial stretching production line is operating stably.

[0125] Specifically, in step S2, the specific process of determining the standard value of each detection point according to the temperature value and pressure value of each detection point obtained in step S1 is as follows:

[0126] S21, firstly, marking the coordinate points corresponding to all the temperature values ​​and pressure values ​​of one of the detection points obtained in step S1 in the temperature-pressure coordinate system;

[0127] S22, in the temperature-pressure coordinate system, draw a circle with the smallest radius so that 70% to 90% of the coordinate points corresponding to the detection points are located in the drawn circle;

[0128] S23, respectively calculating the average values ​​of the horizontal coordinate and the vertical coordinate of each coordinate point in the circle, and using them as the standard values ​​of the temperature and pressure of the detection point;

[0129] S24, traverse all the detection points in turn to obtain the standard value of the temperature and pressure of each detection point.

[0130] In step S22, data with large deviations of 10% to 30% can be eliminated by drawing circles, which simplifies the calculation process and provides a basis for obtaining standard values ​​closer to normal levels in the subsequent step S23.

[0131] Furthermore, in step S3, the process of determining the feature vector group of each detection point according to the standard value of each detection point is as follows:

[0132] S31, number each inspection point according to the order of material movement, and record the number of each inspection point as J ab , where a is the serial number of each process and b is the serial number of the inspection point of the process;

[0133] S32, in the temperature-pressure coordinate system, taking the standard value of the current detection point as the end point and taking the standard values ​​of other detection points as the starting points, drawing multiple vectors, and the obtained multiple vectors are the characteristic vector group of the current detection point;

[0134] S33, traverse all the detection points in sequence to obtain the feature vector group of each detection point.

[0135] As some embodiments of the present invention, in step S32, for example, 11 The standard value of the detection point is the end point, and the standard values ​​of other detection points are the starting points. Draw multiple vectors, and the multiple vectors obtained are the Jth 11 The eigenvector group of the detection points.

[0136] Furthermore, in step S4, when acquiring the temperature and pressure data of each moving detection point, the position of each detection point should be consistent with the position of the detection point when acquiring the detection point data in step S1.

[0137] Furthermore, in step S4, the temperature value and pressure value of each detection point can be measured once in real time; or the temperature value and pressure value of each detection point can be measured multiple times in real time, and the average value thereof can be used as the measured temperature value and pressure value of the detection point.

[0138] Furthermore, in step S5, the process of calculating the simulation value of each detection point according to the temperature value and pressure value of each detection point measured in real time in step S4 is as follows:

[0139] S51, obtaining a feature vector group of each detection point stored in the storage module, and marking the temperature value and pressure value of each detection point measured in real time in step S4 in the temperature-pressure coordinate system to obtain the coordinate point of the measured value corresponding to each detection point;

[0140] S52, sequentially translating each feature vector in the feature vector group of the current detection point so that the starting point of the translated feature vector is the coordinate point of the measured value of each other detection point;

[0141] S53, obtaining the end points of each translated characteristic vector and the temperature and pressure values ​​corresponding to the end points;

[0142] S54, calculating the average value of the temperature value and the average value of the pressure value corresponding to the end point after the translation of each characteristic vector from the same process, and using them as the simulated value of the temperature and pressure from the process, and correspondingly, the coordinate point of the simulated value of the temperature and pressure in the temperature-pressure coordinate system is the simulated coordinate point from the process;

[0143] S55, obtaining the simulated coordinate points of the current detection point from each process (except the process where the current detection point is located);

[0144] S56, sequentially connecting the simulated coordinate points of the current detection point from each process to obtain a polygon;

[0145] S57, finding the center of gravity of the polygon, and the temperature and pressure values ​​corresponding to the center of gravity are the simulation values ​​of the current detection point;

[0146] S58, traverse all the detection points in sequence to obtain the simulation values ​​corresponding to all the detection points.

[0147] As some embodiments of the present application, in step S57, the method for determining the center of gravity of a polygon may be a hanging method or a geometric method, wherein the process of determining the center of gravity of a polygon by the geometric method is as follows: first, connect the diagonals of several polygons to divide the polygon into multiple triangles, and then determine the center of gravity of each triangle respectively. The intersection of the lines connecting the centers of gravity of the multiple triangles is the center of gravity of the polygon.

[0148] The following takes a quadrilateral as an example to illustrate the process of determining its center of gravity: first connect one diagonal of the quadrilateral, so that the quadrilateral becomes a combination of two triangles, then make the center of gravity of the two triangles respectively, denoted as A and B, and connect the two centers of gravity into a straight line AB. Similarly, connect the other diagonal of the quadrilateral, the quadrilateral becomes a combination of another two triangles, then make the center of gravity of the two triangles respectively, denoted as C and D, and connect the two centers of gravity into a straight line CD, then the intersection of straight lines AB and CD is the center of gravity of the quadrilateral.

[0149] On this basis, according to the known geometric theorem: if a figure 3 is formed by the combination of two figures 1 and 2, then the center of gravity of figure 3 must be on the continuous line segment between the center of gravity of figure 1 and the center of gravity of figure 2. The center of gravity of polygons such as pentagons and hexagons can be calculated.

[0150] The following combination Figures 5 and 6 The process described in the above steps S51 to S58 is illustrated by way of example:

[0151] To simplify the description, it is assumed that a biaxial stretching production line includes only four processes, namely process 1, process 2, process 3 and process 4. In particular, process 1 is equipped with one detection point J. 11 , process 2 sets 2 inspection points J 21 and J 22 , process 3 sets 1 detection point J 31 , process 4 sets 1 detection point J 41 When executing steps S51 to S58, the detection point J is first selected. 11 The simulation value calculation is as follows:

[0152] S51, first obtain the characteristic vector group of each detection point stored in the storage module, and mark the temperature value and pressure value of each detection point measured in real time in step S4 in the temperature-pressure coordinate system to obtain the coordinate point of the measured value corresponding to each detection point; wherein, Figure 5 Shows the detection point J 11 The eigenvector group composed of the four eigenvectors of ;

[0153] S52, sequentially translate each feature vector in the feature vector group of the current detection point so that the starting point of the translated feature vector is the coordinate point of the measured value of each other detection point. Figure 6 As shown;

[0154] S53, obtaining the end points of each translated characteristic vector and the temperature and pressure values ​​corresponding to the end points;

[0155] S54, calculating the average value of the temperature value and the average value of the pressure value corresponding to the end point after the translation of each characteristic vector from the same process, and using them as the simulated value of the temperature and pressure from the process, and correspondingly, the coordinate point of the simulated value of the temperature and pressure in the temperature-pressure coordinate system is the simulated coordinate point from the process; Figure 6 In the process 2, the detection point J 21 and J 22 Therefore, we need to calculate J 21 and J 22 The average value of the corresponding temperature value and the average value of the pressure value are used as the simulated values ​​of the temperature and pressure from process 2. Correspondingly, the coordinate point J of the simulated values ​​of the temperature and pressure in the temperature-pressure coordinate system is 模拟2 It is the simulated coordinate point from this process; the other processes 2 and 4 only contain one detection point, so they can be directly used as the simulated values ​​of temperature and pressure from this process;

[0156] S55, obtain the simulated coordinate point J of the current detection point from processes 2, 3, and 4 模拟2 , J 模拟3 and J 模拟4 ;

[0157] S56, connect the simulation coordinate points J in sequence 模拟2 , J 模拟3 and J 模拟4 , and we get a triangle;

[0158] S57, find the center of gravity of the triangle, and the temperature and pressure values ​​corresponding to the center of gravity are the current detection point J 11 The simulated value of

[0159] S58, traversing the detection points in sequence to obtain simulation values ​​corresponding to all detection points.

[0160] Among them, for processes with more than one detection point, by first calculating the simulated coordinate points of the process, the adverse effect of the inconsistent number of detection points in each process on the simulated value of the detection point can be eliminated, so that the contribution of each process in the production line to the simulated value of the current detection point is consistent, and the simulated value can be better adjusted according to the overall status changes of the production line.

[0161] Furthermore, in step S6, the preset threshold value may be determined through experiments or based on experience, such as the preset threshold value may be 2% to 8% of the standard value.

[0162] Furthermore, in steps S1 and S7, when obtaining multiple measured values ​​of each detection point within a period of time, it should be noted that when obtaining the temperature and pressure data of each mobile detection point, the position of each detection point should be consistent with the position of the detection point when the detection point data was obtained in step S1.

[0163] Furthermore, in step S7, when obtaining multiple measured values ​​of each detection point within a period of time, it is preferred that the data detected for the same detection point is no less than 8.

[0164] Furthermore, in step S7, for non-roller devices in the production line, it is only necessary to obtain multiple measured values ​​of each detection point at even intervals in chronological order within a set time.

[0165] Furthermore, in step S9, the average value, maximum value and minimum value of each detection point obtained in step S8 are compared with the standard value obtained in step S2, and the process of issuing a corresponding fault handling instruction according to the comparison result includes:

[0166] S91, first compare the average value of the current detection point with the corresponding standard value obtained in step S2:

[0167] If |average value - standard value| ≤ 3% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 1 is 0;

[0168] If 3% of the standard value < | average value - standard value | ≤ 5% of the standard value, the process is considered to be abnormal, and the abnormality index K 1 is α 1 *|average value-standard value| / standard value;

[0169] If 5% of the standard value is less than |average value-standard value|, the process is considered to be abnormal, and the abnormality index K 1 is α 2 *|average value-standard value| / standard value;

[0170] Among them, 0.5<α 1 <α 2 <3, α 1 and α 2 The specific value of can be determined through experiments;

[0171] S92, then compare the maximum value of the current detection point with the standard value obtained in step S2:

[0172] If |maximum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 2 is 0;

[0173] If 5% of the standard value is less than | maximum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K 2 β 1 *|Maximum value-standard value| / standard value;

[0174] If 8% of the standard value is less than |maximum value-standard value|, the process is considered to be abnormal, and the abnormality index K 2 β 2 *|Maximum value-standard value| / standard value;

[0175] Among them, 0<β 1 <β 2 <0.5, β 1 and β 2 The specific value of can be determined through experiments;

[0176] S93, then compare the minimum value of the current detection point with the standard value obtained in step S2:

[0177] If |minimum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K 3 is 0;

[0178] If 5% of the standard value is less than | minimum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K 3 For γ 1 *|minimum value-standard value| / standard value;

[0179] If 8% of the standard value is less than |minimum value - standard value|, the process is considered to be abnormal, and the abnormality index K 3 For γ 2 *|minimum value-standard value| / standard value;

[0180] Among them, 0<γ 1 <γ 2 <0.5,γ 1 and γ 2 The specific value of can be determined through experiments;

[0181] S94, calculate the total abnormality index K of each detection point 总 , where the total abnormality index K 总 =K 1 +K 2 +K 3 ;

[0182] S95, the total abnormality index K of each detection point 总 Compared with the preset total abnormality index K 异常 For comparison:

[0183] If K 总 ≤K 异常 , then it is considered that the detection point is operating normally;

[0184] If K 异常 <K 总 ≤1.5*K 异常 , it is considered that the detection point is running slightly abnormally, a fault log is generated, and a fault handling instruction - abnormal reminder is issued;

[0185] If 1.5*K 异常 <K 总 ≤2*K 异常 , the detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - delayed shutdown:

[0186] If 2*K 异常 <K 总， The detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - immediate shutdown.

[0187] Furthermore, the position of the detection point, the simulation value obtained in step S5, the comparison result between the difference between the simulation value and the detection value and the preset threshold value in step S6, the average value, maximum value and minimum value of the multiple measured values ​​of the detection point obtained in step S8, and the K value obtained in step S9 are recorded in the fault log. 1 , K 2 , K 3 and K 总 The value of K 总 With K 异常 The comparison results etc.

[0188] In addition, the present invention also provides a storage medium, on which a biaxial stretching production line anti-downtime control program is stored. When the control program is executed by a processor, namely a central processing module, the above-mentioned biaxial stretching production line anti-downtime control method can be implemented.

[0189] The anti-downtime control system and control method of the biaxial stretching production line described in the present invention have the following advantages:

[0190] First, the anti-downtime control system for the biaxial stretching production line of the present invention can be realized by simply modifying the existing production line equipment and adding detection points, which is low-cost and easy to implement;

[0191] Second, the anti-downtime control system and control method of the biaxial stretching production line described in the present invention do not depend on specific working conditions or film materials and have a wide range of applications;

[0192] Third, the anti-downtime control method for the biaxial stretching production line of the present invention fully considers the characteristics that the operating status of the entire production line equipment is closely related, mutually restrained and influenced during the film drawing process. First, the standard value of each detection point with good reference value is obtained through steps S1~S3. Then, in the daily operation of the biaxial stretching production line, the "joint inspection" between different processes is realized through the simulation values ​​in steps S4~S6, avoiding the disadvantage that the traditional single process is inspected independently and cannot reflect the influence of other processes, which easily leads to low accuracy of the detection result;

[0193] Fourth, after the "joint inspection" between different processes is performed in steps S4 to S6, the method for preventing downtime of the biaxial stretching production line of the present invention further performs a regional in-depth inspection of the abnormal process in units of detection points through steps S7 to S9, and calculates the total abnormality index K of each detection point. 总 The degree of abnormality was determined. After determining the degree of abnormality of each detection point, different fault handling methods were used to handle it, achieving accurate measurement and processing of abnormal conditions.

[0194] Although the present invention is disclosed as above, the present invention is not limited thereto. In the description of this specification, the description of reference terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, so the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A biaxial stretching production line anti-downtime control system, the biaxial stretching production line comprising: The batching and mixing device, the crystallization and drying device, the melt extrusion device, the casting cooling device, the synchronous biaxial stretching device and the heat setting device are characterized by: The anti-downtime control system of the biaxial stretching production line includes: a measurement module, a central processing module, a communication module, a storage module and a fault processing module; The measuring module, storage module and fault processing module are respectively connected to the central processing module through the communication module; The measuring module includes a plurality of detection points arranged in the biaxial stretching production line, wherein a plurality of detection points distributed in a spiral shape are arranged on the roller-shaped device in the biaxial stretching production line, a temperature sensor and a pressure sensor are arranged on each detection point, and the central processing module monitors the operation status of the biaxial stretching production line according to the temperature and pressure values ​​detected by each detection point; The control method adopted by the biaxial stretching production line anti-downtime control system comprises the following steps: S1, debug the biaxial stretching production line, and obtain multiple temperature values ​​and multiple pressure values ​​of each detection point at different times when the biaxial stretching production line is running stably; S2, determining the standard value of each detection point according to the temperature value and pressure value of each detection point obtained in step S1; S3, determining a feature vector group of each detection point according to the standard value of each detection point, and storing the feature vector group in a storage module; S4, during the daily operation of the biaxial stretching production line, the temperature and pressure values ​​of each detection point are measured in real time; S5, calculating the simulation value of each detection point according to the temperature value and pressure value of each detection point measured in real time in step S4; S6, comparing the simulation value of each detection point obtained in step S5 with the real-time detection value obtained in step S4, and determining whether the difference between the simulation value and the detection value of the detection point is less than or equal to a preset threshold; if so, it is considered that the detection point is operating normally; if not, it is considered that the detection point may be operating abnormally, and step S7 is continued; S7, obtaining multiple measured values ​​of each detection point within a period of time; S8, respectively determining the average value, maximum value and minimum value of the multiple measured values ​​of each detection point obtained in step S7; S9, comparing the average value, maximum value and minimum value of each detection point obtained in step S8 with the standard value obtained in step S2, and then issuing a corresponding fault handling instruction according to the comparison result.

2. The anti-downtime control system for the biaxial stretching production line according to claim 1 is characterized in that: The roller device comprises: A central shaft (3) connected to the driving device and capable of rotating around its central axis under the drive of the driving device; A roller core (2) which is arranged on the periphery of the central shaft (3) and is capable of rotating synchronously with the central shaft (3); A roller surface portion (1) is arranged on the periphery of the roller core portion (2) and is capable of rotating synchronously with the drive of the central shaft (3); A sensor receiving groove (4) is spirally arranged on the surface of the roller core (2), and a temperature sensor and a pressure sensor are arranged in the sensor receiving groove (4) to form the detection point; The spiral line formed by the plurality of sensor accommodating grooves (4) extends from one end of the roller to the other end, and the pitch of the spiral line is equal to the axial length of the roller core (2).

3. The anti-downtime control system for the biaxial stretching production line according to claim 2 is characterized in that: The surfaces of the temperature sensor and the pressure sensor are flush with the surface of the roller core (2).

4. The anti-downtime control system for the biaxial stretching production line according to claim 2 is characterized in that: The central shaft (3) and the roller core (2) are made of hard alloy, the roller surface (1) is made of a polymer material having elasticity, and the ratio of the thickness of the roller core (2) to the roller surface (1) in the radial direction is ≥50:

1.

5. The anti-downtime control system for the biaxial stretching production line according to claim 1 is characterized in that: A detection point is respectively set on the clamping surface of each chain clamp in the synchronous biaxial stretching device in the biaxial stretching production line, wherein the chain clamp is a device used by the synchronous biaxial stretching device to clamp the film, and the clamping surface of the chain clamp is the position where it contacts the film.

6. The anti-downtime control system for the biaxial stretching production line according to claim 1 is characterized in that: The step S2 comprises: S21, firstly, marking the coordinate points corresponding to all the temperature values ​​and pressure values ​​of one of the detection points obtained in step S1 in the temperature-pressure coordinate system; S22, in the temperature-pressure coordinate system, draw a circle with the smallest radius so that 70% to 90% of the coordinate points corresponding to the detection points are located in the drawn circle; S23, respectively calculating the average values ​​of the horizontal coordinate and the vertical coordinate of each coordinate point in the circle, and using them as the standard values ​​of the temperature and pressure of the detection point; S24, traverse all the detection points in turn to obtain the standard value of the temperature and pressure of each detection point.

7. The anti-downtime control system for the biaxial stretching production line according to claim 1 is characterized in that: The step S3 comprises: S31, number each inspection point according to the order of material movement, and record the number of each inspection point as J ab , where a is the serial number of each process and b is the serial number of the inspection point of the process; S32, in the temperature-pressure coordinate system, taking the standard value of the current detection point as the end point and taking the standard values ​​of other detection points as the starting points, drawing multiple vectors, and the obtained multiple vectors are the characteristic vector group of the current detection point; S33, traverse all the detection points in sequence to obtain the feature vector group of each detection point.

8. The anti-downtime control system for the biaxial stretching production line according to claim 1 is characterized in that: The step S5 comprises: S51, obtaining a feature vector group of each detection point stored in the storage module, and marking the temperature value and pressure value of each detection point measured in real time in step S4 in the temperature-pressure coordinate system to obtain the coordinate point of the measured value corresponding to each detection point; S52, sequentially translating each feature vector in the feature vector group of the current detection point so that the starting point of the translated feature vector is the coordinate point of the measured value of each other detection point; S53, obtaining the end points of each translated characteristic vector and the temperature and pressure values ​​corresponding to the end points; S54, calculating the average value of the temperature value and the average value of the pressure value corresponding to the end point after the translation of each characteristic vector from the same process, and using them as the simulated value of the temperature and pressure from the process, and correspondingly, the coordinate point of the simulated value of the temperature and pressure in the temperature-pressure coordinate system is the simulated coordinate point from the process; S55, obtaining the simulated coordinate points of the current detection point from each process; S56, sequentially connecting the simulated coordinate points of the current detection point from each process to obtain a polygon; S57, finding the center of gravity of the polygon, and the temperature and pressure values ​​corresponding to the center of gravity are the simulation values ​​of the current detection point; S58, traverse all the detection points in sequence to obtain the simulation values ​​corresponding to all the detection points.

9. The anti-downtime control system for the biaxial stretching production line according to claim 1, characterized in that: The step S9 comprises: S91, first compare the average value of the current detection point with the corresponding standard value obtained in step S2: If |average value - standard value| ≤ 3% of the standard value, the detection point is considered to be operating normally, and the abnormality index K1 is 0; If 3% of the standard value < | average value - standard value | ≤ 5% of the standard value, the process is considered to be abnormal, and the abnormality index K1 is α1* | average value - standard value | / standard value; If 5% of the standard value is less than |average value - standard value|, the process is considered to be abnormal, and the abnormality index K1 is α2*|average value - standard value| / standard value; Among them, 0.5<α1<α2<3, and the specific values ​​of α1 and α2 are determined through experiments; S92, then compare the maximum value of the current detection point with the standard value obtained in step S2: If |maximum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K2 is 0; If 5% of the standard value < | maximum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K2 is β1* | maximum value - standard value | / standard value; If 8% of the standard value is less than |maximum value - standard value|, the process is considered to be abnormal, and the abnormality index K2 is β2*|maximum value - standard value| / standard value; Among them, 0<β1<β2<0.5, and the specific values ​​of β1 and β2 are determined through experiments; S93, then compare the minimum value of the current detection point with the standard value obtained in step S2: If |minimum value - standard value| ≤ 5% of the standard value, the detection point is considered to be operating normally, and the abnormality index K3 is 0; If 5% of the standard value < | minimum value - standard value | ≤ 8% of the standard value, the process is considered to be abnormal, and the abnormality index K3 is γ1* | minimum value - standard value | / standard value; If 8% of the standard value is less than |minimum value - standard value|, the process is considered to be abnormal, and the abnormality index K3 is γ2*|minimum value - standard value| / standard value; Among them, 0<γ1<γ2<0.5, and the specific values ​​of γ1 and γ2 are determined through experiments; S94, calculate the total abnormality index K of each detection point 总 , where the total abnormality index K 总 =K1+K2+K3; S95, the total abnormality index K of each detection point 总 Compared with the preset total abnormality index K 异常 For comparison: If K 总 ≤K 异常 , then it is considered that the detection point is operating normally; If K 异常 <K 总 ≤1.5*K 异常 , it is considered that the detection point is running slightly abnormally, a fault log is generated, and a fault handling instruction - abnormal reminder is issued; If 1.5*K 异常 <K 总 ≤2*K 异常 , the detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - delayed shutdown: If 2*K 异常 <K 总， The detection point is considered to be operating abnormally, a fault log is generated, and a fault handling instruction is issued - immediate shutdown.

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