An aluminum strip roll coating production line roll coating production process

Abstract

The present application relates to a kind of production processes of aluminum strip roll coating production line, including unwinding, splicing, inlet loop / unwinding storage rack, pretreatment, primer, printing, face / back coating, roll coating defect detection, outlet loop / coiling storage rack, film coating and winding and the like step.By precisely controlling tension and punching overlap splicing, in combination with chemical cleaning and passivation agent treatment aluminum plate surface, ensure coating adhesion.Primer and face / back coating adopt reverse coating mode, and printing is transferred to the pattern on the primer paint surface.In the aluminum strip roll coating production process, for different background texture roll coating image, it is found that whether there is defect in the image after aluminum strip roll coating, when defect is found, through unwinding storage rack to adjust the running of aluminum strip;Unwinding storage rack precisely controls the tension of aluminum strip during winding on production line, ensure the smooth running of aluminum strip when stop, to avoid the problem of relaxation or tightness when winding, improve the stability of production line and the quality of aluminum strip.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of intelligent monitoring of production equipment, and particularly relates to an aluminum strip roll coating production line roll coating production process. BACKGROUND

[0002] The aluminum strip roll coating production process is a manufacturing process for coating aluminum plates through pretreatment, primer roll coating, drying, topcoat roll coating, and curing, etc., to improve the surface performance and aesthetic appearance of the aluminum plates. The aluminum strip roll coating production process generally includes the following steps: pretreatment: the aluminum plate needs to be surface treated to remove oil stains, oxides, and other impurities, which is achieved through acid pickling, alkali washing, and wax removal, etc. Primer roll coating: after the pretreatment is completed, a layer of primer is roll coated on the aluminum plate. The primer helps to provide good adhesion and corrosion resistance. Drying: the aluminum plate after primer roll coating needs to be dried to completely cure the primer. This is done through an oven or other appropriate drying equipment. Topcoat roll coating: the dried aluminum plate will be roll coated with a topcoat. The topcoat provides the desired color, effect, and protection. Secondary drying and curing: after the topcoat roll coating is completed, the aluminum plate is again dried and cured. This ensures that the topcoat is completely cured, achieving the best weather resistance and appearance effect. Inspection and quality control: after roll coating, the aluminum plate needs to be inspected and quality controlled to ensure that it meets the relevant technical specifications and customer requirements.

[0003] However, in the aluminum strip roll coating production process, the roll coating pattern may become unclear or incomplete due to wear or other reasons after long-term operation of the roll coating wheel. If not discovered in time, it will cause the aluminum strip of this batch to be reworked or scrapped. In addition, due to the size limitation of the aluminum roll and other reasons, the roll needs to be changed during the production process, which will cause the machine to stop, resulting in a large amount of waste. SUMMARY

[0004] The technical solution adopted by the present application to solve the technical problem is:

[0005] The aluminum strip roll coating production line roll coating production process in the present application includes the following steps:

[0006] S1, unwinding: through the rotation of the cantilever type unwinder and the accurate control of the plate surface tension by the motor, the aluminum roll is uniformly and stably unwound;

[0007] S2, splicing: through the mechanical stamping die, the head and tail of the front and rear aluminum strips are overlapped and punched in the direction perpendicular to the aluminum strip, and the splicing strip is inserted and sewn;

[0008] S3, inlet loop / unwinding storage rack: since the production process in the coating process section must be continuous, the aluminum strip inlet of the production line has a stop when the roll is wound, at which time the operation of the aluminum strip is adjusted through the unwinding storage rack;

[0009] S4, pretreatment: through chemical cleaning agent and passivator, the surface of the aluminum plate is cleaned of oil and impurities, and a conversion film is formed on the surface of the aluminum plate to prevent oxidation of the aluminum plate and ensure the adhesion of the coating. It includes the following processes: pickling → squeezing → washing → squeezing → washing → squeezing → passivation → squeezing → drying;

[0010] S5, base coating: the coating is the core part of the production line, including a roller coating machine, an oven, and a cooling system. The base coating is coated by a 4-roll reverse coating with a scraper, including the following processes: base coating → drying → air cooling + water cooling cooling;

[0011] S6, printing: the pattern on the printing roller is transferred to the surface of the base coating paint by a printing machine, including a printing machine, an oven, and a cooling system. It includes the following processes: printing → drying → air cooling + water cooling cooling;

[0012] S7, face / back coating: the coating is the core part of the production line, including a roller coating machine, an oven, and a cooling system. The face coating is coated by a 4-roll reverse coating with a scraper, and the back coating is coated by a 2-roll reverse coating without a scraper. It includes the following processes: face / back coating → drying → air cooling + water cooling cooling;

[0013] S8, roll coating defect detection: an online image-based detection system is used to monitor the roll coating defects of the aluminum strip. When roll coating defects are detected, the running of the aluminum strip is adjusted by the unwinding storage rack to check or adjust the roll;

[0014] S9, exit loop / take-up storage rack: since the production process in the coating process section must be continuous, and the production line aluminum strip outlet has a pause when changing paper tubes, the running of the aluminum strip is adjusted by the take-up storage rack at this time;

[0015] S10, film covering: a protective film for protecting the paint coating is adhered to the surface of the coated aluminum strip by a film covering machine;

[0016] S11, winding: the roll coating finished aluminum strip is neatly wound into a roll by the rotary operation of the cantilever type winding machine.

[0017] Preferably, the unwinding storage rack is used to adjust the running of the aluminum strip during the pause when the aluminum strip is wound at the inlet of the production line, including the following components:

[0018] Main frame: made of steel or aluminum alloy;

[0019] Supporting rollers: a plurality of supporting rollers on the storage rack are used to bear the weight of the aluminum roll and provide support, ensuring that the aluminum roll slides or rolls smoothly; the two ends of the supporting rollers are slidably arranged on the main frame, and the spacing of the supporting rollers is adjusted under the drive of the spacing adjustment device, thereby adjusting the running of the aluminum strip;

[0020] Tension control device: The tension control device adjusts and maintains the tension of the aluminum roll by controlling the spacing adjustment device, thereby adjusting the tension of the roll to control its running state on the storage rack.

[0021] The tension control device includes the following control steps:

[0022] S31, Set up tension sensor: Install a tension sensor on the support roller of the storage rack, which is used to monitor the tension change of the aluminum roll on the storage rack. The sensor is connected to the tension control device.

[0023] S32, Set target tension value: According to the working conditions required by the storage rack and the characteristics of the material, set a target tension value. The value is adjusted according to the actual demand. For example, considering the width, weight and running speed of the aluminum roll to determine the target tension value.

[0024] S33, Real-time monitoring of tension: Real-time monitoring of the tension of the aluminum roll on the storage rack through the sensor, and transmitting the monitored tension value to the tension control device.

[0025] S34, Compare actual tension with target tension: The control system compares the actual tension value with the set target tension value, and calculates the error signal between the two.

[0026] S35, Control signal generation: According to the error signal, the tension control device generates corresponding control signal for adjusting the spacing adjustment device of the storage rack.

[0027] S36, Spacing adjustment device: According to the control signal, the tension of the aluminum roll is changed by adjusting the spacing adjustment device. The specific adjustment method is determined according to the design of the storage rack and the characteristics of the mechanism, such as adjusting the spacing of the support roller through hydraulic system.

[0028] S37, Feedback control: Continue to monitor and compare the actual tension with the target tension, and execute steps 34 to 36 in a loop until the actual tension reaches or approaches the target tension, realizing real-time adjustment and control of the tension of the aluminum roll, and further ensuring the running of the aluminum strip during the stop of the aluminum strip at the inlet of the production line.

[0029] Preferably, in step S9, an online image-based detection system is used to monitor the roll coating defects of the aluminum strip. In the image analysis and processing algorithm of roll coating defect detection, an automatic threshold processing method is used. Because the image-based presentation is multimodal histogram distribution, and the related defects usually occupy a very small part of the captured image, a two-step automatic threshold algorithm is used, in which a statistical process control-based algorithm is used to determine the initial threshold to remove most of the background pixels, which helps to use the automatic threshold processing method to determine the final threshold to isolate the fine defect area.

[0030] Preferably, drying is performed by a drying oven.

[0031] Preferably, the system further comprises a deviation rectifying system, including deviation rectifying devices respectively arranged at the outlet of the pre-treatment drying oven, the outlet guide roller of the primer drying oven, the printing machine, the outlet guide roller of the topcoat drying oven, and the base of the winding machine.

[0032] Compared with the prior art, the present application has the following advantages:

[0033] (1) The present application can better control the tension of the aluminum strip, improve the stability of the product, improve the firmness of the joint by improved tabbing method, solve the running problem caused by the stop of the aluminum strip at the inlet and outlet, improve the continuity of the production line, make the surface of the aluminum plate cleaner and the adhesion better by optimizing the pre-treatment process, improve the coating quality and production efficiency by improving the primer, printing and topcoat / backcoat processes, solve the problem of winding stop by using the winding storage rack, and improve the efficiency of the production line; and the film coating technology protects the coating quality.

[0034] (2) In the aluminum strip roll coating production process, a two-step threshold algorithm is used for roll-coated images with different background textures to detect whether there are defects in the roll-coated images of the aluminum strip. When defects are found, the winding storage rack is used to adjust the running of the aluminum strip to check or adjust the roll to avoid production loss.

[0035] (3) The winding storage rack precisely controls the tension of the aluminum strip during the winding process on the production line, ensures the smooth running of the aluminum strip when it stops, avoids the problem of relaxation or tightness of the wound material when it stops, improves the stability of the production line and the quality of the aluminum strip. At the same time, through the automatic adjustment of the tension control device, the need for manual intervention can be reduced, the production efficiency and operation safety can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a flow chart of the roll coating production process of the aluminum strip roll coating production line in the present application;

[0037] Figure 2 is a control flow chart of the tension control device of the roll coating production process of the aluminum strip roll coating production line in the present application;

[0038] Figure 3 is a flow chart of the roll coating defect detection of the roll coating production process of the aluminum strip roll coating production line in the present application. DETAILED DESCRIPTION

[0039] For the purposes of making the present application, technical solutions and advantages clearer, the following will combine the drawings in the embodiments of the present application to describe the technical solutions in the embodiments of the present application in more detail. In the drawings, the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The structure and technical solutions of the present application will be further described below in combination with the drawings, and an embodiment of the present application is given.

[0040] Figures 1-2 It is a roll coating production process of an aluminum strip roll coating production line in the present application, comprising the following steps:

[0041] S1, unwinding: through the rotation operation of a cantilever type unwinder and the accurate control of the plate tension by a motor, the uniform and stable operation of the aluminum roll is ensured to be opened;

[0042] S2, patching: through a mechanical stamping die, the head and tail of the front and rear aluminum strips are overlapped and punched in the direction perpendicular to the aluminum strip, and a patch strip is penetrated to be sewn;

[0043] S3, inlet loop / unwinding storage rack: since the production process in the coating process section must be continuously operated, and the aluminum strip inlet of the production line has a stop when winding, at this time the operation of the aluminum strip is adjusted through the unwinding storage rack;

[0044] S4, pretreatment: through chemical cleaning agent and passivator, the oil stains and impurities on the surface of the aluminum plate are removed clean, so that a conversion film is formed on the surface of the aluminum plate to prevent the oxidation of the aluminum plate and ensure the adhesion of the coating. Including the following procedures: pickling → squeezing → cleaning → squeezing → cleaning → squeezing → passivation → squeezing → drying;

[0045] S5, base coating: coating is the core part of the production line, including a roll coater, an oven, and a cooling system. The base coating is coated in a 4-roll reverse coating mode with a scraper, including the following procedures: base coating → drying → air cooling + water cooling cooling;

[0046] S6, printing: through a printing machine, the patterns on the printing roller are transferred to the surface of the base coating paint, including a printing machine, an oven, and a cooling system. Including the following procedures: printing → drying → air cooling + water cooling cooling;

[0047] S7, Face / back coating: Coating is the core part of the production line, including roll coater, oven, cooling system. The face coating adopts 4-roll reverse coating with scraper, and the back coating adopts 2-roll reverse coating without scraper. The process includes the following steps: face / back coating→drying→air cooling+water cooling;

[0048] S8, Roll coating defect detection: An online image-based detection system is used to monitor the roll coating defects of the aluminum strip. When roll coating defects are detected, the running of the aluminum strip is adjusted through the unwinding storage rack, so as to check or adjust the roll;

[0049] S9, Outlet loop / take-up storage rack: Since the coating process section must be continuously running during production, and the aluminum strip outlet of the production line has a downtime when changing paper tubes, the running of the aluminum strip is adjusted through the take-up storage rack at this time;

[0050] S10, Film covering: The protective film for protecting the paint coating is adhered to the surface of the coated aluminum strip through the film covering unit;

[0051] S11, Winding: The roll-coated finished aluminum strip is neatly wound into a roll through the rotary operation of the cantilever winding machine.

[0052] Among them, the unwinding storage rack is used to adjust the running of the aluminum strip through the unwinding storage rack during the downtime when the aluminum strip is wound at the inlet of the production line, which includes the following components:

[0053] Main frame: made of steel or aluminum alloy;

[0054] Supporting rollers: A plurality of supporting rollers on the storage rack are used to bear the weight of the aluminum roll and provide support, ensuring that the aluminum roll slides or rolls smoothly; the two ends of the supporting rollers are slidably arranged on the main frame, and the spacing adjustment device is driven to adjust the spacing of the supporting rollers, thereby adjusting the running of the aluminum strip;

[0055] Tension control device: The tension control device adjusts and maintains the tension of the aluminum roll by controlling the spacing adjustment device, thereby adjusting the tension of the roll to control its running state on the storage rack.

[0056] Among them, the tension control device includes the following control steps:

[0057] S31, Set the tension sensor: Install a tension sensor on the supporting rollers of the storage rack, which is used to monitor the tension change of the aluminum roll on the storage rack. The sensor is connected to the tension control device.

[0058] S32, Set the target tension value: According to the working conditions required by the storage rack and the characteristics of the material, set a target tension value. This value is adjusted according to actual needs. For example, consider the width, weight and running speed of the aluminum roll to determine the target tension value.

[0059]

[0059] S33, real-time monitoring of tension: real-time monitoring of the tension of the aluminum coil on the storage rack is performed by a sensor, and the monitored tension value is transmitted to the tension control device.

[0060] S34, comparison of actual tension and target tension: the control system compares the actual tension value with the set target tension value, and calculates the error signal between the two.

[0061] S35, control signal generation: according to the error signal, the tension control device generates a corresponding control signal for adjusting the spacing adjustment device of the storage rack.

[0062] S36, spacing adjustment device: according to the control signal, the tension of the aluminum coil is changed by adjusting the spacing adjustment device. The specific adjustment method is determined according to the design of the storage rack and the characteristics of the mechanism, for example, adjusting the spacing of the supporting rollers through a hydraulic system.

[0063] S37, feedback control: continue to monitor and compare the actual tension and the target tension, and execute steps 34 to 36 in a loop until the actual tension reaches or approaches the target tension, realizing real-time adjustment and control of the tension of the aluminum coil, and further ensuring the running of the aluminum strip during the stop at the entrance of the production line.

[0064] Preferably, drying is performed through a drying oven.

[0065] Preferably, it also includes a correction system, which includes a correction device respectively arranged at the outlet of the pre-treatment drying oven, the outlet guide roller of the primer drying oven, the printing machine, the outlet guide roller of the topcoat drying oven, and the base of the winding machine.

[0066] Among them, a set of correction devices are arranged at the outlet of the pre-treatment drying oven to prevent the aluminum strip from deviating; a set of correction devices are arranged at the outlet guide roller of the primer drying oven to prevent the aluminum strip from deviating; a set of correction devices are arranged at each group of printing machines to cope with precise printing, color matching, and frame matching; a set of correction devices are arranged at the outlet guide roller of the topcoat drying oven to prevent the aluminum strip from deviating; and a set of correction devices are arranged at the base of the winding machine to neatly wind the finished aluminum strip into a roll.

[0067] Among them, in step S9, an online image-based detection system is used to monitor the roll coating defects of the aluminum strip. In the image analysis and processing algorithm of roll coating defect detection, an automatic threshold processing method is used. Since the image-based presentation is multimodal histogram distribution, and the related defects usually occupy a very small part of the captured image, a two-step automatic threshold algorithm is used, in which a statistical process control-based algorithm is used to determine the initial threshold to remove most of the background pixels, which helps to use the automatic threshold processing method to determine the final threshold for isolating the fine defect area.

[0068] Assuming g i(x, y) is the ith captured grayscale image of size m x n, where x = 0, 1,..., m-1 and y = 0, 1,..., n-1, g i The range of (x, y) values is from 0 to L-1, where L is the number of different gray levels.

[0069] To find the threshold using statistical process control, first compute the average gray level μ i of the ith captured grayscale image as follows:

[0070]

[0071] The corresponding variance v i is computed as follows:

[0072]

[0073] Given μ i and v i , the threshold T 1i for the ith image is defined as:

[0074] T 1i = μ i - kσ i

[0075] where, k is an adjustable control factor that sets the threshold according to the distance from the average gray value. The choice of control factor k is a matter of preference when using statistical process control threshold. A constant control factor with best performance is chosen during training, such as k = 2.

[0076] To compute the threshold using the adaptive threshold selection algorithm, the number of pixels q(I) at gray level I is given by:

[0077]

[0078] where,

[0079] Remove the pixels with gray levels greater than the threshold T 1i , i.e., if I > T 1i , q(I) = 0.

[0080] Given the number of pixels associated with a given gray level I, the occurrence probability h(I) is:

[0081]

[0082] The cumulative probability p0(t) of gray levels less than the threshold t is given by:

[0083]

[0084] Similarly, the cumulative probability p1(t) of gray levels greater than the threshold t is given by the following formula:

[0085]

[0086] The average gray level u0(t) of pixels with a gray level less than t is:

[0087]

[0088] Similarly, the average gray level u1(t) of pixels with a gray level greater than t is:

[0089]

[0090] Maximum inter-class variance of pixel gray levels less than and greater than threshold t It is given by the following formula:

[0091]

[0092] The optimal adaptive threshold selection algorithm for the i-th image has a threshold T. 2i This is achieved by finding the gray level t that maximizes the inter-class variance σ, such as:

[0093]

[0094] Pixels with gray levels less than T2i are classified as defective pixels:

[0095] If g i (x, y) < T 2i g i (x, y) = L-1

[0096] Pixels with a gray level greater than T2i are classified as background pixels:

[0097] If g i (x, y) > T 2i g i (x, y) = 0.

[0098] A two-step approach combining statistical process control (SPC) thresholding and an adaptive threshold selection algorithm: First, SPC is applied to find the threshold T1i. 1i This removes most of the background. Then, an adaptive threshold selection algorithm is applied to the remaining pixels to find a threshold T for defect segmentation. 2i Gray level less than T 2ipixels are defined as defect pixels. A two-step thresholding algorithm is employed, which uses a statistical process control to generate a preliminary threshold to remove most of the background in the captured image, and then an adaptive thresholding algorithm to generate a final threshold, which the image is segmented by the preliminary threshold. Then the defect pixels are segmented from the original captured image using the final threshold, which can segment the defect pixels at a consistent rate in both uniform and non-uniform background textures. In the production process of aluminum strip roll coating, the two-step thresholding algorithm is used to detect whether there are defects in the image after roll coating of the aluminum strip, and when defects are found, the running of the aluminum strip is adjusted through the unwinding storage rack, so that the roll can be checked or adjusted, avoiding production loss.

[0099] Compared with the prior art, the present application has the following advantages:

[0100] (1) Better control of the tension of the aluminum strip, improving the stability of the product; improved tabbing method improves the firmness of the joint; solves the running problem caused by the pause at the inlet and outlet of the aluminum strip, improving the continuity of the production line; optimization of the pretreatment process makes the surface of the aluminum plate cleaner and the adhesion better; improvement of the primer, printing and face / back coating processes improves the coating quality and production efficiency; the use of the winding storage rack solves the problem of winding pause, improving the efficiency of the production line; the film coating technology protects the coating quality.

[0101] (2) In the production process of aluminum strip roll coating, the two-step thresholding algorithm is used to detect whether there are defects in the image after roll coating of the aluminum strip, and when defects are found, the running of the aluminum strip is adjusted through the unwinding storage rack, so that the roll can be checked or adjusted, avoiding production loss.

[0102] (3) The unwinding storage rack precisely controls the tension of the aluminum strip during the winding process on the production line, ensuring smooth running of the aluminum strip when paused, to avoid problems such as relaxation or tightness of the wound material when paused, improving the stability of the production line and the quality of the aluminum strip. At the same time, through the automatic adjustment of the tension control device, the need for manual intervention can also be reduced, improving production efficiency and operational safety.

[0103] The part of the present application not described in detail is the common knowledge in the field.

[0104] The above examples fully and effectively achieve the purpose of the present application. Those skilled in the art can understand that the present application includes but is not limited to what is described in the drawings and the above specific embodiments. Although the present application has been described in relation to the presently preferred and most practical embodiments, it should be understood that the present application is not limited to the disclosed embodiments, and any modification that does not deviate from the functional and structural principles of the present application will be included in the scope of the claims.

Claims

1. An aluminum strip roll coating production line roll coating production process characterized by, Comprising the following steps: S1, unwinding: through cantilever type unwinding machine rotation operation and motor accurate control of the surface tension, to ensure the aluminum roll uniform speed and smooth operation open; S2, patch: through mechanical stamping die in the direction of the vertical aluminum strip on the front and rear of the aluminum strip head tail overlap punching, and into the patch strip, suture; S4, pretreatment: through chemical cleaning agent and passivator, the aluminum plate surface oil, impurities clean, make the aluminum plate surface form a layer of conversion film, prevent the oxidation of aluminum plate to ensure the adhesion of the coating; including the following processes: pickling, squeezing, cleaning, squeezing, cleaning, squeezing, passivation, squeezing, drying; S5, primer: coating is the core part of the production line, including roll coater, oven, cooling system; primer is coated by 4 roll inverse coating with scraper, including the following processes: primer, drying, air cooling and water cooling cooling; S6, printing: through the printing machine, the pattern on the printing roller transfer to the primer paint surface, including printing machine, oven, cooling system; including the following processes: printing, drying, air cooling and water cooling cooling; S7, face / back coating: coating is the core part of the production line, including roll coater, oven, cooling system; face coating is coated by 4 roll inverse coating with scraper, back coating is coated by 2 roll inverse coating without scraper; including the following processes: face / back coating, drying, air cooling and water cooling cooling; S8, roll coating defect detection: using image-based online detection system, monitoring the roll coating defects of aluminum strip; when detecting roll coating defects, the running of aluminum strip is adjusted through the unwinding storage rack, so as to check or adjust the roll; S9, outlet loop / take-up storage rack: because the production process of coating process section must be continuous, and there is a stop when the paper tube is replaced at the outlet of the aluminum strip of the production line, at this time the running of the aluminum strip is adjusted through the take-up storage rack; S10, film covering: through the film covering machine group, the protective film for protecting the paint coating is adhered to the surface of the coated aluminum strip; In step S8, an image-based online detection system is used to monitor the roll coating defects of the aluminum strip; a two-step threshold algorithm is used to generate a preliminary threshold value to remove most of the background in the captured image, and then an adaptive threshold selection algorithm is used to generate a final threshold value, the image is segmented by the preliminary threshold value, and the defect pixels are segmented from the original captured image by using the final threshold value; in detail: The corresponding variance υi is calculated as follows: The average gray level u1(t) of the pixels with a gray level greater than t is: Assume is the i-th captured grayscale image of size m x n, where x = 0, 1,..., m-1 and y = 0, 1,..., n-1, the value of gi(x, y) ranges from 0 to L-1, where L is the number of different gray levels; To find the threshold using statistical process control, first calculate the average gray level of the i-th captured gray scale image The formula is as follows: The optimal adaptive threshold selection algorithm threshold T2i of the i-th image is found by finding the gray level t that maximizes the inter-class variance σ, as follows: Given μi and υi, the threshold value of the ith image is defined as: wherein, k is an adjustable control factor that sets the threshold according to the distance from the average gray value; To calculate the threshold using the adaptive threshold selection algorithm, the number of pixels at gray level I is given by the equation: wherein, removing pixels having a gray scale greater than a threshold value if , ; Given the number of pixels associated with a given gray level I, the occurrence probability is: cumulative probability of gray levels less than threshold t is given by: cumulative probability of gray levels greater than threshold t is given by: average gray level of pixels having a gray level less than t is: The unwinding storage rack is used to adjust the running of the aluminum strip through the unwinding storage rack when the production line aluminum strip inlet is stopped, comprising the following components: maximum between-class variance of pixel gray levels less than and greater than the threshold t is given by Main frame: made of steel or aluminum alloy; Pixels with a gray level less than T2i are classified as defective pixels: if , ; pixels with a gray level greater than T2i are classified as background pixels: if , .

2. The roll coating production process of an aluminum strip roll coating production line according to claim 1, characterized in that, ​ ​ Support rollers: A plurality of support rollers on the storage rack are used to bear the weight of the aluminum roll and provide support, ensuring that the aluminum roll slides or rolls smoothly; the two ends of the support rollers are slidably arranged on the main frame, and the adjustment of the spacing of the support rollers is realized under the driving of the spacing adjustment device, thereby adjusting the running of the aluminum strip; Tension control device: the tension control device adjusts and maintains the tension of the aluminum roll by controlling the spacing adjustment device, thereby adjusting the tension of the roll to control its running state on the storage rack.

3. An aluminum strip roll coating production line roll coating production process as claimed in claim 2, characterized in that, The tension control device includes the following control steps: S31, setting a tension sensor: a tension sensor is installed on the support roller of the storage rack, which is used to monitor the tension change of the aluminum roll on the storage rack; the sensor is connected to the tension control device; S32, setting a target tension value: according to the required working conditions of the storage rack and the characteristics of the material, a target tension value is set; the target tension value is adjusted according to the actual demand; S33, real-time monitoring of tension: the tension of the aluminum roll on the storage rack is monitored in real time through the sensor, and the monitored tension value is transmitted to the tension control device; S34, comparing the actual tension with the target tension: the control system compares the actual tension value with the set target tension value, and calculates the error signal between the two; S35, control signal generation: according to the error signal, the tension control device generates corresponding control signal for adjusting the spacing adjustment device of the storage rack; S36, spacing adjustment device: according to the control signal, the tension of the aluminum roll is changed by adjusting the spacing adjustment device; S37, feedback control: continue to monitor and compare the actual tension with the target tension, and execute steps 34 to 36 cyclically until the actual tension reaches or approaches the target tension, realizing real-time adjustment and control of the tension of the aluminum roll, and further guaranteeing the running of the aluminum strip when the production line aluminum strip inlet is wound.

4. The roll coating process for an aluminum strip roll coating production line according to claim 1, characterized in that, Drying is carried out through a drying box.

5. An aluminum strip roll coating production line roll coating production process as defined in claim 4, characterized in that, It also includes a correction system, which includes a correction device respectively arranged at the outlet of the pre-treatment drying box, the outlet guide roller of the primer drying box, the printing machine, the outlet guide roller of the topcoat drying box, and the base of the winding machine.

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