Food packaging film double-layer composite laminating machine and laminating method

Abstract

The invention relates to the technical field of composite films, in particular to a food packaging film double-layer composite laminating machine and a laminating method. The method comprises the following steps: acquiring film data and temperature data; a tension fluctuation index is calculated based on tension difference and tension deviation conditions collected by a sensor, and abnormal nodes are screened; analyzing the correlation between the abnormal node and a target node based on the distance between the abnormal node and the unwinding side and the distance between the abnormal node and the winding side and the film compounding speed in combination with a tension fluctuation index so as to screen the abnormal side; adjusting the initial gain coefficient based on the abnormal node and the relevant features of the winding side and the unwinding side to obtain an adjusted gain coefficient; further adjusting the unwinding side based on the temperature to obtain an abnormal gain coefficient; according to different abnormal sides, different weights are carried out to obtain a final gain coefficient, and tension control is realized; and detecting the quality of the produced composite film. The probability of film wrinkling, stretching and the like is reduced, and the quality of finished products is effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of composite films, and in particular to a double-layer composite laminating machine and laminating method for food packaging films. Background Art

[0002] Food packaging film is a common material in the food packaging industry, primarily serving to protect food safety, extend food shelf life, and enhance packaging aesthetics. To further enhance food packaging's moisture resistance, barrier properties, mechanical strength, and aesthetics, companies typically combine two or more materials with complementary properties through a multi-layer composite process to create multi-layer composite films. A double-layer composite structure is currently the most fundamental and widely used.

[0003] Existing multi-layer film composite methods mainly include dry composite method, wet composite method and hot melt adhesive composite method, etc. The main principle of all of them is to apply adhesive between two layers of substrate, and perform different methods of dry adhesion according to the different states of the adhesive, so as to achieve film composite. However, traditional equipment can only complete a single-layer composite of two layers of substrate and one layer of adhesive in one process. If it is necessary to complete the composite twice or more (i.e., to form a multi-layer film), multiple repeated operations are required. Repeated operations will lead to reduced production efficiency. In addition, when bonding a single-layer composite film to the substrate, it is easy to cause wrinkles, stretching deformation or misalignment of the composite film due to unstable tension control, resulting in reduced product quality. Summary of the Invention

[0004] In order to solve the technical problem of low film quality, the present application provides a double-layer composite laminating machine and laminating method for food packaging film. The technical solutions adopted are as follows:

[0005] In a first aspect, the present application proposes a method for laminating a double-layer food packaging film, the method comprising the following steps:

[0006] Collect the film tension, film lamination speed, and temperature of the magnetic powder brake during the lamination process;

[0007] Each tension sensor is considered a node. A tension variation curve is constructed for the tension of each node and divided into sampling periods. The ratio of the standard deviation of the tension to the mean tension within the sampling period is used as the tension fluctuation amplitude. The tension deviation coefficient is obtained based on the difference between the maximum and minimum tension within the sampling period, and the difference between the mean tension of the sampling period and the theoretical tension. The tension fluctuation index is calculated based on the tension fluctuation amplitude and the tension deviation coefficient. The tension fluctuation index is compared with the abnormal threshold to filter out abnormal nodes.

[0008] Tension sensors placed around the unwinding and winding sides are recorded as target nodes. The tension delay coefficient is determined based on the distance between the target node and the abnormal node and the film lamination speed. The correlation between the target node and the abnormal node is obtained based on the ratio of all tension fluctuation indices of the abnormal node and the target node to the standard deviation of all tensions of the abnormal node and the target node. The degree of association between the abnormal node and the target node is determined based on the correlation and the tension delay coefficient. The abnormal side is screened by comparing the degree of association with the abnormal parameters.

[0009] An envelope is constructed using the tension variation curve, and the slope of the curve is calculated after fitting as the tension fluctuation trend. The tension fluctuation index is weighted using the distance from the abnormal node to the unwinding side and the rewinding side as the weight to obtain the corresponding tension index. The initial gain coefficient is adjusted based on the roll diameter change rate to obtain the adjusted gain coefficient. For the unwinding side, a compensation coefficient is obtained based on the temperature at each moment and the ideal operating temperature, and the adjusted gain coefficient is further adjusted based on the tension fluctuation trend to obtain the abnormal gain coefficient. Depending on the abnormal side, the adjusted gain coefficient and the abnormal gain coefficient are weighted using the correlation index of the abnormal side and the non-abnormal side to obtain the final gain coefficient to achieve tension control.

[0010] Carry out quality inspection on the composite film after production.

[0011] In the above scheme, the present application can collect data on the surface tension of the film at different laminating stages by arranging multiple film tension sensors in the laminating machine, providing a force data basis for determining abnormal tension nodes. Through abnormal node analysis and node correlation analysis, the correlation between the current abnormal tension node and different sides (unwinding side, winding side) can be determined, and then which side has the abnormality, thereby improving the abnormality traceability capability of the equipment during the laminating process. At the same time, the tension abnormalities on both sides of the laminating machine can be regulated in real time based on temperature changes and roll diameter changes, which greatly improves the adaptability during the laminating process, reduces the probability of film wrinkles, stretching, etc., and effectively improves the quality of the finished product.

[0012] In one embodiment, the method of constructing a tension variation curve for the tension of each node and dividing the sampling period is as follows:

[0013] Each time the equipment is running, the tension collected at each node is sorted in chronological order to obtain a tension change curve, the time it takes for the roller to rotate one circle around each node is used as the sampling period of the node, and the tension change curve is divided based on the sampling period.

[0014] In one embodiment, the tension deviation coefficient is positively correlated with the difference between the maximum tension and the minimum tension, and is positively correlated with the difference between the mean tension of the sampling period and the theoretical tension; the theoretical tension is the mean of all tensions in the history of each node.

[0015] In one embodiment, the tension fluctuation index is positively correlated with the tension fluctuation amplitude and the tension deviation coefficient, respectively.

[0016] In one embodiment, the method for determining the tension delay coefficient according to the distance between the target node and the abnormal node and the film composite speed is:

[0017] L x,k represents the distance between the kth abnormal node and the xth target node, v0 represents the film recombination velocity, norm() represents the normalization function, τ x,k Represents the tension delay coefficient between the kth abnormal node and the xth target node.

[0018] In one embodiment, the method for obtaining the correlation between the target node and the abnormal node based on the ratio of all tension fluctuation indexes of the abnormal node and the target node to the standard deviation of all tensions of the abnormal node and the target node is:

[0019] b k,j represents the tension fluctuation index of the kth abnormal node in the jth sampling period, b j (x) represents the tension fluctuation index of the x-th target node in the j-th sampling period, σ k represents the standard deviation of all tensions of the kth abnormal node, σ1(x) represents the standard deviation of all tensions of the xth target node, represents the correlation between the xth target node and the kth abnormal node.

[0020] In one embodiment, the method of obtaining the compensation coefficient based on the temperature at each moment and the ideal working temperature, and further adjusting the adjusted gain coefficient in combination with the fluctuation trend of the tension to obtain the abnormal gain coefficient is as follows:

[0021] The expression of the compensation coefficient is:

[0022] θ1=norm(ε×(w t -w0)),w t represents the temperature at time t, w0 represents the ideal operating temperature of the magnetic powder brake, ε represents the preset temperature variation coefficient, norm() represents the normalization function, and θ1 represents the temperature compensation coefficient on the unwinding side;

[0023] The expression of abnormal gain coefficient is:

[0024] θ1 represents the temperature compensation coefficient on the unwinding side, q t Indicates the fluctuation trend of tension at time t, Y P Indicates the adjusted proportional gain coefficient, YI represents the adjusted integral gain coefficient, skd() represents the bipolar sigmoid function, and Y′ P Indicates the abnormal proportional gain coefficient, Y′ I Indicates abnormal integral gain coefficient.

[0025] In one embodiment, the method for obtaining the final gain coefficient by weighting the adjusted gain coefficient and the abnormal gain coefficient according to the correlation index between the abnormal side and the non-abnormal side is:

[0026] If one of the winding side and the unwinding side is abnormal, the expression of the final gain coefficient is:

[0027] Y′ P,1 Indicates the adjusted proportional gain coefficient on the non-abnormal side, Y′ P,2 Indicates the abnormal proportional gain coefficient on the abnormal side, Represents the normalized value of the correlation index between the winding side and the unwinding side, Y′ I,1 Indicates the adjusted integral gain coefficient on the non-abnormal side, Y′ I,2 Indicates the adjusted integral gain coefficient on the abnormal side, Y PZ Represents the final proportional gain coefficient, Y IZ Indicates the final integral gain coefficient.

[0028] In one embodiment, the correlation index between the winding side and the unwinding side is the average value of the correlation between any two nodes on the winding side and the unwinding side.

[0029] On the second aspect, the present application proposes a double-layer composite laminating machine for food packaging film to realize a double-layer composite laminating method for food packaging film, the laminating machine including: a film material roller, a paper material roller, a glue coating roller, a positioning roller, a winding drum, a tensioning roller, a pressure roller, and a glue roller; the unwinding side is a film material roller and a paper material roller; the winding side is a winding drum.

[0030] The beneficial effects of this application are:

[0031] This application can collect data on the surface tension of the film at different laminating stages by arranging multiple film tension sensors in the laminating machine, providing a force data basis for determining abnormal tension nodes. Through abnormal node analysis and node correlation analysis, the correlation between the current abnormal tension node and different sides (unwinding side, winding side) can be determined, and then which side has the abnormality, thereby improving the abnormality traceability capability of the equipment during the laminating process. At the same time, the tension abnormalities on both sides of the laminating machine can be regulated in real time based on temperature changes and roll diameter changes, which greatly improves the adaptability during the laminating process, reduces the probability of film wrinkles, stretching, etc., and effectively improves the quality of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present application or the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 A flow chart of a double-layer composite lamination method for food packaging film provided in one embodiment of the present application;

[0034] Figure 2 is the tension change curve;

[0035] Figure 3 It is a schematic diagram of the overall structure of the laminating machine;

[0036] Figure 4 This is the main view of the laminating machine;

[0037] Figure 5 This is a top view of the laminating machine;

[0038] Figure 6 Schematic diagram of the internal structure of the glue storage tank;

[0039] Figure 7 for Figure 4 Schematic diagram of the enlarged part of A. DETAILED DESCRIPTION

[0040] To further illustrate the technical means and effectiveness of this application's objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of a double-layer composite laminating machine and laminating method for food packaging film proposed in this application. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0041] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0042] A food packaging film double-layer composite laminating machine and laminating method embodiment:

[0043] The following describes in detail a double-layer composite laminating machine and laminating method for food packaging film provided by the present application with reference to the accompanying drawings.

[0044] See also Figure 1, which shows a flow chart of a double-layer composite laminating machine and laminating method for food packaging film provided by one embodiment of the present application, the method comprising the following steps:

[0045] Step S001: collecting film data and temperature data.

[0046] While the laminating machine is operating, tension sensors are installed on the equipment to measure the surface tension of the film in real time. These sensors are positioned around the laminating machine's rollers to measure the rotational speed of each roller. The collected tension data is uploaded to the control system in real time and stored. The tension sensor's acquisition frequency is 20 Hz. The rotational speed of the pressure roller is recorded as the film laminating speed.

[0047] Magnetic powder brakes are installed on the rotating shafts of the film material roller and the paper material roller, and the driving base at the reel is a servo motor. The magnetic powder brake controls the torque through current and actively adjusts the unwinding resistance to balance the film tension in the unwinding section. The servo motor monitors the roll diameter to achieve taper tension control, that is, the tension automatically decreases as the roll diameter increases.

[0048] Collect temperature data and current data of the magnetic powder brake, and obtain voltage data of the servo motor.

[0049] At this point, the film tension, composite speed, magnetic powder brake current, temperature, and servo motor voltage are obtained.

[0050] Step S002: Calculate the tension fluctuation index based on the tension difference and tension deviation collected by the sensor to filter out abnormal nodes.

[0051] According to the multiple tension sensors arranged inside the laminating machine, the tension changes at different stages of film lamination can be obtained. By analyzing the fluctuation of the tension at each sensor separately, the abnormal fluctuation points, that is, the locations where the tension becomes unstable, can be determined.

[0052] Each tension sensor is regarded as a node. For each node, when the device is running, all tensions are combined into a tension change curve in time sequence. Figure 2 shown.

[0053] The time it takes for the roller to rotate one circle around each node is taken as the sampling period of the node, and the tension change curve is divided into periods based on the sampling period.

[0054] For each node, the mean and standard deviation of the tension in each sampling period are calculated, and the tension fluctuation amplitude is obtained based on the two. The larger the tension fluctuation amplitude, the worse the tension stability in the sampling period.

[0055] Preferably, in this embodiment, the expression of the tension fluctuation amplitude is:

[0056] σ i,j represents the standard deviation of all tensions at the i-th node in the j-th sampling period, represents the mean value of all tensions of the i-th node in the j-th sampling period, α i,j Represents the tension fluctuation amplitude of the i-th node in the j-th sampling period.

[0057] Furthermore, the maximum tension and the minimum tension are obtained in each sampling period, and the tension deviation coefficient is determined based on the theoretical tension at the i-th node when the equipment is running. The theoretical tension is the average of all tensions in the history of the node.

[0058] The tension deviation coefficient is positively correlated with the difference between the maximum tension and the minimum tension, and is positively correlated with the difference between the mean value of the tension in the sampling period and the theoretical tension.

[0059] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large; the specific relationship is determined by actual application and this application does not impose any special restrictions.

[0060] Preferably, in this embodiment, the expression of the tension deviation coefficient is:

[0061] Z i,j_max represents the maximum tension of the i-th node in the j-th sampling period, Z i,j_min represents the minimum tension of the i-th node in the j-th sampling period, represents the mean value of all tensions of the i-th node in the j-th sampling period, Z i,0 represents the theoretical tension of the i-th node, β i,j Represents the tension deviation coefficient of the i-th node in the j-th sampling period.

[0062] The greater the difference between the tension in the current sampling period and the tension in the history, the greater the deviation. The greater the amplitude of the tension change in the sampling period, the greater the deviation.

[0063] The tension fluctuation index of the sampling period is calculated based on the tension fluctuation amplitude and tension deviation coefficient of the sampling period of each node.

[0064] The tension fluctuation index is positively correlated with the tension fluctuation amplitude and the tension deviation coefficient respectively.

[0065] Preferably, in this embodiment, the expression of the tension fluctuation index is:

[0066] b i,j=norm(α i,j ×β i,j ), α i,j represents the tension fluctuation amplitude of the i-th node in the j-th sampling period, β i,j represents the tension deviation coefficient of the i-th node in the j-th sampling period, norm() represents the normalization function, b i,j represents the tension fluctuation index of the i-th node in the j-th sampling period. In this embodiment, the normalization function uses the maximum and minimum value normalization method.

[0067] For each node, the time interval from the end of each sampling period to the current time is used as a weight to weight the tension fluctuation indexes of all sampling periods to obtain the tension fluctuation index of each node.

[0068] The tension fluctuation index is compared with the abnormal threshold to screen abnormal nodes. In this embodiment, if the tension fluctuation index of the node is greater than or equal to the abnormal threshold, the film tension of the node is unstable and marked as an abnormal node. The abnormal threshold is 0.6.

[0069] At this point, the abnormal nodes are obtained after marking the nodes.

[0070] Step S003 , analyzing the correlation between the abnormal node and the target node based on the distance between the abnormal node and the unwinding side, the winding side, and the film lamination speed in combination with the tension fluctuation index, thereby screening the abnormal side.

[0071] In food packaging film laminating machines, the role played by the rollers in the film laminating process varies depending on their position. Some rollers belong to the winding side, while other rollers belong to the unwinding side. It should be noted that the unwinding and winding speeds of the unwinding and winding sides affect the tension during the film laminating process. Therefore, the tension fluctuations at different nodes are mostly related to these two sides. Therefore, by analyzing the correlation, it can be determined which side has a greater impact on the abnormal node, thereby more effectively stabilizing the tension fluctuations.

[0072] The tension fluctuation index of the abnormal node is compared with that of the winding side and the unwinding side nodes respectively. Combined with the distance between the nodes and the special parameters of the winding side and the unwinding side, the degree of correlation between the abnormal node and the two sides is determined, and then the abnormal side is determined.

[0073] After filtering out the abnormal nodes through the above steps, the distance between each node on the unwinding and winding sides and the abnormal node is obtained. The tension delay coefficient is calculated based on the distance and the film lamination speed. The nodes on the unwinding and winding sides are recorded as target nodes.

[0074] Preferably, the expression of the tension delay coefficient is:

[0075] Lx,k represents the distance between the kth abnormal node and the xth target node, v0 represents the film recombination velocity, norm() represents the normalization function, τ x,k Represents the tension delay coefficient between the kth abnormal node and the xth target node.

[0076] For target and abnormal nodes, the correlation between the two nodes is determined based on the tension fluctuation index and the standard deviation of all tensions in the same period. Within the same sampling period, the larger the product of the tension fluctuation index of the target and abnormal nodes, the more consistent their abnormal tension fluctuations. Furthermore, the smaller the tension standard deviation of the two nodes, the more significant their abnormal tension fluctuations are, and the greater the cross-correlation index between the two nodes.

[0077] Preferably, the expression of the correlation between the target node and the abnormal node is:

[0078] b k,j represents the tension fluctuation index of the kth abnormal node in the jth sampling period, b j (x) represents the tension fluctuation index of the x-th target node in the j-th sampling period, σ k represents the standard deviation of all tensions of the kth abnormal node, σ1(x) represents the standard deviation of all tensions of the xth target node, represents the correlation between the xth target node and the kth abnormal node.

[0079] The degree of association between the abnormal node and the target node is determined according to the correlation and tension delay coefficient between the target node and the abnormal node.

[0080] The degree of association is positively correlated with the relevance between the target node and the abnormal node, and negatively correlated with the tension delay coefficient between the target node and the abnormal node.

[0081] It should be noted that negative correlation means that when one variable increases, the other variable decreases accordingly, and the two variables change in opposite directions. When one variable changes from large to small or from small to large, the other variable also changes from small to large or from large to small. The specific relationship is determined by actual application and this application does not impose any special restrictions.

[0082] Preferably, in this embodiment, the expression of the degree of association is:

[0083] represents the correlation between the xth target node and the kth abnormal node, τ x,k represents the tension delay coefficient between the kth abnormal node and the xth target node, exp() represents the exponential function with the natural constant as the base, norm() represents the normalization function, G x,kIndicates the degree of association between the xth target node and the kth abnormal node.

[0084] The average value of the association degree between all target nodes on the winding side and the kth abnormal node is calculated as the association degree between the winding side and the kth abnormal node; the average value of the association degree between all target nodes on the unwinding side and the kth abnormal node is calculated as the association degree between the unwinding side and the kth abnormal node.

[0085] The degree of association is compared with the abnormal parameter to determine the abnormal side.

[0086] Preferably, in this embodiment, if the correlation degree between the abnormal node and the unwinding side is greater than 0.7, and the correlation degree between the abnormal node and the winding side is less than 0.3, the unwinding side is considered to be the abnormal side. If the correlation degree between the abnormal node and the winding side is greater than 0.7, and the correlation degree between the abnormal node and the unwinding side is less than 0.3, the winding side is considered to be the abnormal side. If the correlation degree between the abnormal node and both the unwinding side and the winding side is between 0.45-0.55, both sides are considered to be the abnormal side.

[0087] At this point, the abnormal side is obtained.

[0088] Step S004: Adjust the initial gain coefficient based on the abnormal node and the relevant characteristics of the winding side and the unwinding side to obtain the adjusted gain coefficient; then further adjust the unwinding side based on the temperature to obtain the abnormal gain coefficient; and perform different weightings according to different abnormal sides to obtain the final gain coefficient to achieve tension control.

[0089] After determining the abnormal side in the laminating machine, the PID control algorithm is combined with the magnetic powder brake and the servo motor to stabilize the film tension during the lamination process. The magnetic powder brake is for the unwinding side, and the servo electrode is for the winding side. The larger the abnormal index of the node, the greater the impact on the PID control algorithm parameters.

[0090] At the same time, when one side of the laminating machine is controlled, the other side also needs to be compensated accordingly to avoid sudden changes in tension. For example, in order to reduce the tension, the unwinding side increases the unwinding speed. At this time, the winding side needs to increase the winding speed appropriately to adapt to the changes in the composite speed. That is, coordinated control is performed according to the correlation of the tension changes on both sides to achieve tension stability.

[0091] For the tension variation curve of the abnormal node, construct its upper and lower envelopes, and calculate the mean of the upper and lower envelopes at the same time to obtain the fitting curve. The slope of the fitting curve at each time is used as the tension fluctuation trend.

[0092] In the PID control algorithm, the proportional gain (P) is mainly used for control, the integral gain (I) is mainly used to eliminate errors, and the differential gain (D) is mainly used for prediction. The process of tension stabilization mainly involves the adjustment of the proportional gain (P) and the integral gain (I).

[0093] The gain coefficient is adjusted differently according to the abnormal side.

[0094] When the abnormal side is the unwinding side, control is performed based on the temperature at each moment. The distance from the abnormal node to the unwinding side is used as a weight to sum the tension fluctuation index of the abnormal node, which is used as the unwinding side tension index. If there are multiple nodes on the unwinding side, the distance from the abnormal node to the unwinding side is the average of the distances from the abnormal node to all nodes on the unwinding side. The ratio of the decrease in the unwinding side coil diameter to time is normalized and used as the coil diameter change rate.

[0095] According to the change rate of the roll diameter and the tension index on the unwinding side, the initial integral gain coefficient and the initial proportional gain coefficient are adjusted respectively. The specific expressions are as follows:

[0096] Y I =Y I_0 ×(1-μ×v1), Indicates the tension index on the unwinding side, v1 indicates the change rate of the roll diameter on the unwinding side, Y P_0 Indicates the initial proportional gain coefficient, Y I_0 Indicates the initial integral gain coefficient, Y P Represents the adjusted proportional gain coefficient, Y I represents the adjusted integral gain coefficient, μ represents the adjustment parameter. In this embodiment, the adjustment parameter is 0.2, the initial proportional gain coefficient is 0.3, and the initial integral gain coefficient is 0.005.

[0097] Furthermore, the temperature compensation coefficient θ1 of the unwinding side is obtained by combining the temperature variation coefficient ε of the magnetic powder brake and the real-time temperature difference. The higher the temperature, the worse the braking ability and the larger the compensation coefficient.

[0098] Preferably, in this embodiment, the expression of the compensation coefficient is:

[0099] θ1=norm(ε×(w t -w0)),w t represents the temperature at time t, w0 represents the ideal operating temperature of the magnetic powder brake, ε represents the temperature variation coefficient, norm() represents the normalization function, and θ1 represents the temperature compensation coefficient on the unwinding side.

[0100] In this embodiment, the ideal operating temperature is 25 degrees. The temperature variation coefficient is obtained through experimental control. In this embodiment, the temperature variation coefficient is 1.

[0101] Based on the tension fluctuation trend and temperature compensation coefficient, the gain coefficient is further adjusted to obtain the abnormal proportional gain coefficient and abnormal integral gain coefficient. The expression is:

[0102] θ1 represents the temperature compensation coefficient on the unwinding side, q t Indicates the fluctuation trend of tension at time t, Y P Represents the adjusted proportional gain coefficient, Y I represents the adjusted integral gain coefficient, skd() represents the bipolar sigmoid function, which is used to normalize the internal data to the interval of (-1, 1), Y′ P Indicates the abnormal proportional gain coefficient, Y′ I Indicates abnormal integral gain coefficient.

[0103] Thus, when the abnormal side is the unwinding side, an abnormal proportional gain coefficient and an abnormal integral gain coefficient are acquired.

[0104] When the abnormal side is the winding side, the distance from the abnormal node to the winding side is used as the weight to perform weighted summation of the tension fluctuation index of the abnormal node, which is used as the tension index of the winding side; similarly, the ratio of the reduction amplitude of the winding diameter on the winding side to the time is obtained and normalized as the winding diameter change rate of the winding side.

[0105] The initial integral gain coefficient and initial proportional gain coefficient are adjusted based on the winding diameter change rate and the winding tension index. Since the servo motor is less affected by temperature, temperature compensation is not required. The abnormal proportional gain coefficient and abnormal integral gain coefficient on the winding side are the adjusted proportional gain coefficient and integral gain coefficient, respectively.

[0106] The correlation between each node on the winding side and each node on the unwinding side is calculated, and the mean of all correlations is calculated as the association index between the winding side and the unwinding side.

[0107] If one side is abnormal and the other side is not abnormal, the gain coefficient of the abnormal side is adjusted based on the correlation index of the two sides and then combined with the gain coefficient of the non-abnormal side to obtain the final gain coefficient. The expression is:

[0108] Y′ P,1 Indicates the adjusted proportional gain coefficient on the non-abnormal side, Y′ P,2 Indicates the abnormal proportional gain coefficient on the abnormal side, Represents the normalized value of the correlation index between the winding side and the unwinding side, Y′ I,1Indicates the adjusted integral gain coefficient on the non-abnormal side, Y′ I,2 Indicates the adjusted integral gain coefficient on the abnormal side, Y PZ Represents the final proportional gain coefficient, Y IZ Indicates the final integral gain coefficient.

[0109] If both are abnormal, restart the device for adjustment.

[0110] The current of the magnetic powder brake and the voltage of the servo motor are controlled based on the final proportional gain coefficient and the final integral gain coefficient to achieve tension control.

[0111] Step S005: Perform quality inspection on the composite film.

[0112] Through the above steps, by controlling the tension, the film tension can be stabilized during the composite process of the single-layer composite film and the substrate, thereby reducing the probability of wrinkles, stretching, tearing, etc. in the film.

[0113] After the lamination is completed, a double-layer composite film is obtained on the winding side. According to the quality requirements of the finished film, the composite quality of the film is evaluated. If there are quality problems with the film, the defect is evaluated. At the same time, if the defect is more serious, it means that the laminating machine may have an equipment failure, so it is necessary to stop the laminating machine and perform fault detection on it.

[0114] See also Figures 3 to 7 The present application provides a laminating machine for realizing the above-mentioned laminating method, including a frame 1, a film material roller 2, a paper material roller 3, a glue storage tank 4, a glue coating roller 5, a positioning roller 6, a hexagonal shaft 7, a hexagonal hole 8, a winding drum 9, a tensioning roller 10, a mounting frame 11, an electric cylinder 12, a fixing plate 13, a pressure roller 14, a drive box 15, a control panel 16, an air cylinder 17, a drive seat 18, a mounting plate 19, a fixing frame 20, a glue coating roller 21, a feeding port 22, a positioning shaft 23, a limit groove 24, and a limit plate 25.

[0115] Figure 7 for Figure 3 A partial enlargement of center A.

[0116] In the laminating machine, there is a tension sensor around each roller; including: film material roller 2, paper material roller 3, glue roller 5, positioning roller 6, winding roller 9, tension roller 10, pressure roller 14, and glue roller 21.

[0117] The unwinding side is a film material roller 2 and a paper material roller 3; the winding side is a winding drum 9.

[0118] It should be noted that the above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and should all be included in the scope of protection of the present application.

[0119] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A double-layer composite laminating method for food packaging film, characterized in that: The method comprises the following steps: Collect the film tension, film lamination speed, and temperature of the magnetic powder brake during the lamination process; Each tension sensor is considered a node. A tension variation curve is constructed for the tension of each node and divided into sampling periods. The ratio of the standard deviation of the tension to the mean tension within the sampling period is used as the tension fluctuation amplitude. The tension deviation coefficient is obtained based on the difference between the maximum and minimum tension within the sampling period, and the difference between the mean tension of the sampling period and the theoretical tension. The tension fluctuation index is calculated based on the tension fluctuation amplitude and the tension deviation coefficient. The tension fluctuation index is compared with the abnormal threshold to filter out abnormal nodes. Tension sensors placed around the unwinding and winding sides are recorded as target nodes. The tension delay coefficient is determined based on the distance between the target node and the abnormal node and the film lamination speed. The correlation between the target node and the abnormal node is obtained based on the ratio of all tension fluctuation indices of the abnormal node and the target node to the standard deviation of all tensions of the abnormal node and the target node. The degree of association between the abnormal node and the target node is determined based on the correlation and the tension delay coefficient. The abnormal side is screened by comparing the degree of association with the abnormal parameters. An envelope is constructed using the tension variation curve, and the slope of the curve is calculated after fitting as the tension fluctuation trend. The tension fluctuation index is weighted using the distance from the abnormal node to the unwinding side and the rewinding side as the weight to obtain the corresponding tension index. The initial gain coefficient is adjusted based on the roll diameter change rate to obtain the adjusted gain coefficient. For the unwinding side, a compensation coefficient is obtained based on the temperature at each moment and the ideal operating temperature, and the adjusted gain coefficient is further adjusted based on the tension fluctuation trend to obtain the abnormal gain coefficient. Depending on the abnormal side, the adjusted gain coefficient and the abnormal gain coefficient are weighted using the correlation index of the abnormal side and the non-abnormal side to obtain the final gain coefficient to achieve tension control. Carry out quality inspection on the composite film after production.

2. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The method for constructing a tension variation curve for the tension of each node and dividing the sampling period is as follows: Each time the equipment is running, the tension collected at each node is sorted in chronological order to obtain a tension change curve, the time it takes for the roller to rotate one circle around each node is used as the sampling period of the node, and the tension change curve is divided based on the sampling period.

3. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The tension deviation coefficient is positively correlated with the difference between the maximum tension and the minimum tension, and is positively correlated with the difference between the mean value of the tension in the sampling period and the theoretical tension; The theoretical tension is the average of all tensions in the history of each node.

4. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The tension fluctuation index is positively correlated with the tension fluctuation amplitude and the tension deviation coefficient respectively.

5. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The method for determining the tension delay coefficient according to the distance between the target node and the abnormal node and the film composite speed is: L x,k represents the distance between the kth abnormal node and the xth target node, v0 represents the film recombination velocity, norm() represents the normalization function, τ x,k Represents the tension delay coefficient between the kth abnormal node and the xth target node.

6. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The method for obtaining the correlation between the target node and the abnormal node based on the ratio of all tension fluctuation indexes of the abnormal node and the target node to the standard deviation of all tensions of the abnormal node and the target node is: b k,j represents the tension fluctuation index of the kth abnormal node in the jth sampling period, b j (x) represents the tension fluctuation index of the x-th target node in the j-th sampling period, σ k represents the standard deviation of all tensions of the kth abnormal node, σ1(x) represents the standard deviation of all tensions of the xth target node, represents the correlation between the xth target node and the kth abnormal node.

7. A method for double-layer composite lamination of food packaging film according to claim 1, characterized in that: The method for obtaining the compensation coefficient based on the temperature at each moment and the ideal working temperature, and further adjusting the adjusted gain coefficient in combination with the fluctuation trend of the tension to obtain the abnormal gain coefficient is as follows: The expression of the compensation coefficient is: θ1=norm(ε×(w t -w0)),w t represents the temperature at time t, w0 represents the ideal operating temperature of the magnetic powder brake, ε represents the preset temperature variation coefficient, norm() represents the normalization function, and θ1 represents the temperature compensation coefficient on the unwinding side; The expression of abnormal gain coefficient is: θ1 represents the temperature compensation coefficient on the unwinding side, q t Indicates the fluctuation trend of tension at time t, Y P Indicates the adjusted proportional gain coefficient, Y I represents the adjusted integral gain coefficient, skd() represents the bipolar sigmoid function, and Y′ P Indicates the abnormal proportional gain coefficient, Y′ I Indicates abnormal integral gain coefficient.

8. A double-layer composite laminating method for food packaging film according to claim 1, characterized in that: The method for obtaining the final gain coefficient by weighting the adjusted gain coefficient and the abnormal gain coefficient according to the correlation index between the abnormal side and the non-abnormal side is as follows: If one of the winding side and the unwinding side is abnormal, the expression of the final gain coefficient is: Y′ P,1 Indicates the adjusted proportional gain coefficient on the non-abnormal side, Y′ P,2 Indicates the abnormal proportional gain coefficient on the abnormal side, Represents the normalized value of the correlation index between the winding side and the unwinding side, Y′ I,1 Indicates the adjusted integral gain coefficient on the non-abnormal side, Y′ I,2 Indicates the adjusted integral gain coefficient on the abnormal side, Y PZ Represents the final proportional gain coefficient, Y IZ Indicates the final integral gain coefficient.

9. A double-layer composite laminating method for food packaging film according to claim 8, characterized in that: The correlation index between the winding side and the unwinding side is the average value of the correlation between each node on the winding side and the unwinding side.

10. A double-layer composite laminating machine for food packaging film, characterized in that: The laminating machine comprises: a film material roller, a paper material roller, a glue coating roller, a positioning roller, a winding drum, a tension roller, a pressure roller, and a glue roller; the unwinding side is the film material roller and the paper material roller; the winding side is the winding drum.

Images