A paper roll slitting scheduling optimization method and system considering paper disease transverse position

Abstract

The application discloses a paper roll slitting scheduling optimization method and system considering paper disease transverse position, wherein the method comprises the following steps: obtaining mother roll paper disease detection data to determine the forbidden zone interval, generating a candidate cutting mode according to order requirements, dividing the mother roll width into available intervals based on the forbidden zone interval and filtering the candidate cutting mode for feasibility to eliminate unfeasible modes, immediately entering the slitting process after the mother roll is unloaded, maintaining the current cutting mode and its corresponding forbidden zone characteristics, calculating the forbidden zone similarity when a new mother roll arrives, continuing to use if the similarity is similar and the current mode is feasible, otherwise switching to a new mode, selecting a target cutting mode and establishing an integer programming model for global optimization with the minimum number of tool changes and paper edge waste as the target, and outputting the scheduling scheme and production summary table. The application reduces the waste rate by actively avoiding the paper disease area, reduces the number of tool changes by dynamic mode maintenance, improves the slitting efficiency, and can be used for high-speed special paper production of cigarette paper base paper and glassine paper.

Description

Technical Field

[0001] This invention belongs to the field of automation technology in the papermaking industry, and particularly relates to a method and system for optimizing paper roll slitting and scheduling considering the lateral position of paper defects. Background Technology

[0002] Paper roll slitting is a crucial step in the papermaking process. Its task is to cut the large master rolls produced by the paper machine into finished paper rolls of varying widths and quantities according to customer order requirements. The quality of the slitting scheduling plan directly impacts a company's raw material utilization, production efficiency, and economic benefits. Currently, paper companies primarily employ scheduling methods based on minimizing paper edge waste. Existing technologies commonly use integer linear programming models to solve for the optimal cutting scheme with the goal of minimizing paper edge waste. For example, some literature documents optimized scheduling models with no leftover scrap, minimizing paper edge waste by exhaustively enumerating feasible cutting schemes and using a solver to solve integer programming problems. Further research has considered inventory costs, establishing a hybrid integer linear programming model for paper roll slitting and inventory management.

[0003] However, none of the above methods consider the distribution of paper defects in the master roll. In actual production, master rolls often have paper defects such as holes, dirt spots, and wrinkles. These defects have specific lateral positions in the width direction. If the cutting scheme places these defects within the finished paper roll's width, the finished product will be scrapped, resulting in material waste. Existing methods only target paper edge waste and cannot avoid finished product losses caused by paper defects. Some existing technologies address paper defects, but only for rescheduling after paper breaks or defects occur. For example, some research-developed paper roll scheduling and slitting integrated optimization systems include a rescheduling module. When paper breaks or defects occur during slitting, the system remodels and reschedules based on the completed output. These methods only remedy the situation after defects occur and fail to proactively avoid defects during the scheduling stage. Furthermore, they do not utilize the lateral position information of the paper defects for pre-optimization of the cutting scheme. Therefore, they still cannot effectively reduce the scrap rate caused by paper defects.

[0004] Furthermore, existing scheduling methods typically prioritize raw material utilization as the sole optimization objective, neglecting the cost of blade changes during the slitting process. When switching cutting schemes, slitting machines require adjusting blade positions, necessitating downtime and consuming labor and time. This is particularly problematic in high-speed specialty paper production, where frequent blade changes significantly reduce slitting efficiency and increase labor burden. Currently, no slitting scheduling optimization method simultaneously considers the lateral location of paper defects and blade change costs. In summary, existing paper roll slitting and scheduling technologies suffer from the following shortcomings: they fail to consider the lateral location of paper defects, treating the mother roll as undifferentiated raw material, making it impossible to proactively avoid defects during scheduling, resulting in defects falling within the finished paper roll width and causing waste; they do not consider blade change costs, focusing solely on raw material utilization, leading to frequent blade changes and reduced slitting efficiency; and they lack dedicated scheduling methods for high-speed specialty papers, making it difficult to meet the dual requirements of quality and efficiency for high-speed specialty papers such as cigarette paper base paper and glassine paper. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a paper roll slitting and production optimization method and system that considers the lateral position of paper defects, thereby resolving the problems existing in the prior art.

[0006] In a first aspect, to achieve the above objective, the present invention provides a method for optimizing paper roll slitting and production scheduling considering the lateral position of paper defects, comprising the following steps: Obtain paper defect detection data of the master roll, and determine the restricted area in the width direction of the master roll based on the paper defect detection data; Candidate cutting patterns are generated based on order requirements. Each candidate cutting pattern includes a combination of widths of finished paper rolls and the number of finished paper rolls of each width in that pattern. The width of the master roll is divided into an available range according to the restricted area. The finished paper rolls in the candidate cutting modes are placed into the available range in turn for feasibility judgment. The candidate cutting modes that are judged to be feasible are marked as feasible modes, and the infeasible candidate cutting modes are eliminated. The system maintains the current cutting mode and its corresponding restricted area features. When a new master volume arrives, the restricted area of ​​the new master volume is obtained and the similarity with the restricted area features corresponding to the current cutting mode is calculated. Based on the similarity judgment result and the feasibility of the current cutting mode for the restricted area of ​​the new master volume, it is determined whether to switch to a new cutting mode. Select the target cutting mode from the feasible modes, and assign the cutting mode to each master volume so that the allocation result meets the order requirements; Output a production scheduling plan, which includes the cutting mode and cutter position for each master roll.

[0007] Optionally, the process of determining the restricted area includes: when there are multiple paper defects in the mother roll, the lateral position of each paper defect in the width direction of the mother roll is represented as an interval, and the set of all intervals is taken as the restricted area, which is the union of multiple discontinuous intervals.

[0008] Optionally, the feasibility assessment process includes: dividing the width of the master roll into usable intervals according to the restricted area; arranging the finished paper rolls in the candidate cutting modes in descending order of width; attempting to place each finished paper roll into the usable intervals in the order of arrangement, and selecting the first usable interval that can accommodate the width of the finished paper roll; when all the finished paper rolls in the candidate cutting modes can be placed into the usable intervals, marking the candidate cutting mode as a feasible mode, otherwise marking it as an infeasible mode.

[0009] Optionally, when there are multiple arrangement orders for finished paper rolls within the available range in the same candidate cutting mode, the feasibility judgment process includes: trying various arrangement orders in turn, and when there is at least one arrangement order that allows all finished paper rolls in the candidate cutting mode to be placed in the available range, marking the candidate cutting mode as a feasible mode.

[0010] Optionally, the process of determining whether to switch to a new cutting mode includes: the system maintaining the current cutting mode and its corresponding restricted area features; when a new parent volume arrives, obtaining the restricted area interval of the new parent volume, and calculating the similarity between the restricted area interval of the new parent volume and the restricted area features corresponding to the current cutting mode; when the similarity is greater than a preset threshold and the current cutting mode is feasible for the restricted area interval of the new parent volume, continuing to use the current cutting mode; when the similarity is less than or equal to the preset threshold, or the current cutting mode is not feasible for the restricted area interval of the new parent volume, selecting a cutting mode feasible for the restricted area interval of the new parent volume from the feasible modes as the new cutting mode and triggering a tool-changing operation, updating the current cutting mode to the new cutting mode, and updating the restricted area features corresponding to the current cutting mode to the restricted area interval of the new parent volume.

[0011] Optionally, the process of assigning cutting modes to each master roll includes: selecting a target cutting mode from the feasible modes, and establishing an integer programming model with the number of cutter changes and paper edge waste as optimization objectives; the integer programming model uses the number of times each cutting mode is used as a decision variable, the feasibility of the cutting mode assigned to each master roll within its restricted area as a constraint, and the requirement that the output of all master rolls meets the order demand as a constraint; solving the integer programming model, determining the number of times each cutting mode is used based on the solution results, and assigning cutting modes sequentially according to the arrival order of each master roll, with different cutting modes between adjacent master rolls counted as one cutter change.

[0012] Secondly, the present invention also provides a paper roll slitting and scheduling optimization system that considers the lateral position of paper defects, for implementing a paper roll slitting and scheduling optimization method that considers the lateral position of paper defects, the system comprising: The data acquisition module is used to acquire paper defect detection data and order requirements of the master roll, and determine the restricted area in the width direction of the master roll based on the paper defect detection data; The pattern generation module is used to generate candidate cutting patterns according to the order requirements. Each candidate cutting pattern includes a combination of widths of finished paper rolls and the number of finished paper rolls of each width in the pattern. The feasibility filtering module is used to divide the width of the master roll into an available range according to the restricted range, put the finished paper rolls in the candidate cutting modes into the available range for feasibility judgment, mark the candidate cutting modes that are judged to be feasible as feasible modes, and remove the candidate cutting modes that are not feasible. The real-time decision module is used to maintain the current cutting mode and its corresponding restricted area features. When a new parent volume arrives, it obtains the restricted area of ​​the new parent volume and calculates the similarity with the restricted area features corresponding to the current cutting mode. Based on the similarity judgment result and the feasibility of the current cutting mode for the restricted area of ​​the new parent volume, it determines whether to switch to a new cutting mode. The optimization solution module is used to select a target cutting mode from the feasible modes, assign cutting modes to each master volume, and make the allocation results meet the order requirements. The production scheduling output module is used to output a production scheduling plan, which includes the cutting mode and cutter position for each master roll.

[0013] Thirdly, the present invention also provides a computer terminal device, comprising: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the steps of the paper roll slitting and scheduling optimization method that takes into account the lateral position of paper defects in the first aspect described above.

[0014] Fourthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, it implements the steps of the paper roll slitting and scheduling optimization method considering the lateral position of paper defects in the first aspect described above.

[0015] Fifthly, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the paper roll slitting and scheduling optimization method considering the lateral position of paper defects in the first aspect described above.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: This invention provides a paper roll slitting and scheduling optimization method and system that considers the lateral position of paper defects. By introducing constraints on the lateral position of paper defects during the scheduling stage, and using the restricted area as the basis for judging the feasibility of the cutting mode, this invention ensures that the cutting scheme actively avoids areas with paper defects, preventing paper defects from falling within the finished paper roll width. This significantly reduces the scrap rate of finished products caused by paper defects. Compared with the existing technology that only remedies the situation after the paper defects occur, this invention achieves proactive avoidance of paper defects. Through dynamic pattern maintenance and similarity judgment, this invention only changes the blade when there is a significant change in the restricted area, under the condition of immediate slitting of the mother roll. This avoids frequent blade changes, reduces the burden of manual operation, and improves slitting efficiency. Compared with the existing technology that focuses on the utilization rate of a single raw material and ignores the cost of blade changes, this invention also takes into account the cost of blade changes. This invention is particularly suitable for the production of high-speed specialty papers such as cigarette paper base paper and glassine paper. By actively avoiding paper defects and optimizing the cost of changing blades, it meets the dual requirements of quality and efficiency for high-speed specialty papers and has strong industrial applicability. At the same time, it can be solved accurately using integer programming methods or quickly using heuristic algorithms, adapting to production scheduling scenarios of different scales and constraints. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart illustrating a paper roll slitting and production optimization method considering the lateral position of paper defects according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the defect-prone area of ​​the mother roll paper according to an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the division of usable intervals based on restricted area intervals according to an embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the feasibility of placing the finished paper roll into the usable area according to an embodiment of the present invention. Figure 5 This is a flowchart illustrating the real-time splitting decision and dynamic mode maintenance in an embodiment of the present invention. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the steps illustrated in the flowcharts of the accompanying drawings may be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowcharts, in some cases, the steps shown or described may be executed in an order different from that herein.

[0020] Embodiment One As shown in Figures 1-5 , the present embodiment provides an optimization method for paper roll slitting production scheduling considering the transverse position of paper defects, comprising: acquiring paper defect detection data of a parent roll, and determining a forbidden zone interval in the width direction of the parent roll according to the paper defect detection data; generating candidate cutting modes according to order requirements, wherein each of the candidate cutting modes includes a width combination of finished paper rolls and the number of finished paper rolls of each width in the mode; dividing the width of the parent roll into available intervals according to the forbidden zone intervals, sequentially placing the finished paper rolls in the candidate cutting modes into the available intervals for feasibility judgment, marking the candidate cutting modes judged to be feasible as feasible modes, and eliminating the infeasible candidate cutting modes; the system maintains the current cutting mode and its corresponding forbidden zone feature, when a new parent roll arrives, acquiring the forbidden zone interval of the new parent roll and calculating the similarity with the forbidden zone feature corresponding to the current cutting mode, and determining whether to switch to a new cutting mode according to the similarity judgment result and the feasibility of the current cutting mode for the forbidden zone interval of the new parent roll; selecting a target cutting mode from the feasible modes, and allocating cutting modes to each parent roll so that the allocation result meets the order requirements; outputting a production scheduling scheme, wherein the production scheduling scheme includes the cutting mode of each parent roll and the position of the cutting knife.

[0021] Further, the process of determining the forbidden zone interval includes: when there are multiple paper defects in the parent roll, respectively representing the transverse positions of each paper defect in the width direction of the parent roll in the form of intervals, and taking the set of all intervals as the forbidden zone interval, wherein the forbidden zone interval is the union of a plurality of discontinuous intervals.

[0022] Specifically, the implementation process of the present embodiment includes: acquiring the paper defect detection data of each parent roll, extracting the transverse position information of the paper defects in the width direction of the parent roll, and generating a forbidden zone interval. The forbidden zone interval is represented as [l, r], where 0 ≤ l < r ≤ W, and W is the width of the parent roll; when there are multiple paper defects in the parent roll, the forbidden zone interval is the union of a plurality of discontinuous intervals.

[0023] Further, generating candidate cutting modes according to order requirements specifically includes: generating candidate cutting modes according to order requirements. The order requirements include the width w of the finished paper rollj and demand b j Each candidate cutting pattern is represented as a vector (a1, a2, ..., a...). n ), where a j Indicates a width of w j The number of finished paper rolls in this pattern. Candidate cutting patterns can be generated by enumeration or dynamic programming.

[0024] Furthermore, the feasibility assessment process includes: dividing the width of the master roll into usable intervals based on the restricted area; arranging the finished paper rolls in the candidate cutting modes in descending order of width; attempting to place each finished paper roll into the usable intervals in sequence according to the arrangement order, and selecting the first usable interval that can accommodate the width of the finished paper roll; when all finished paper rolls in the candidate cutting mode can be placed into the usable intervals, marking the candidate cutting mode as a feasible mode, otherwise marking it as an infeasible mode.

[0025] Furthermore, when there are multiple arrangement orders for finished paper rolls within the available range in the same candidate cutting mode, the feasibility judgment process includes: trying various arrangement orders in turn, and when there is at least one arrangement order that allows all finished paper rolls in the candidate cutting mode to be placed in the available range, marking the candidate cutting mode as a feasible mode.

[0026] Specifically, the implementation process of this embodiment includes: For each parent volume, the feasibility of candidate cutting modes is assessed based on its restricted area, specifically including: 1) Divide the width of the parent volume into several usable intervals based on the restricted intervals of the parent volume. Let the width of the parent volume be W, and the restricted intervals be [l1, r1], [l2, r2], ..., [l...]. k ,r k The usable intervals are [0, l1), (r1, l2), ..., (r... k ,W].

[0027] 2) Arrange the finished paper rolls in the candidate cutting modes in descending order of width, and try to put them into the available range one by one. Select the first available range that can accommodate its width.

[0028] 3) If all finished paper rolls can be placed in the available area, the candidate cutting mode is marked as a feasible mode; otherwise, it is marked as an infeasible mode and discarded.

[0029] When there are multiple arrangements of the same candidate cutting pattern, if there is at least one arrangement that allows all finished paper rolls to be placed in the usable area, then the candidate cutting pattern is marked as a feasible pattern.

[0030] When the master roll is free of paper defects, the restricted area is an empty set, and the available area is the entire width of the master roll. At this time, all cutting modes that meet the width and number of cutters constraints are feasible modes.

[0031] When all candidate cutting patterns are marked as infeasible, the system outputs a prompt message indicating that the master volume cannot be used for the current order and suggests downgrading its use or taking other actions.

[0032] Furthermore, the process of determining whether to switch to a new cutting mode includes: the system maintaining the current cutting mode and its corresponding restricted area features; when a new parent volume arrives, obtaining the restricted area interval of the new parent volume, and calculating the similarity between the restricted area interval of the new parent volume and the restricted area features corresponding to the current cutting mode; when the similarity is greater than a preset threshold and the current cutting mode is feasible for the restricted area interval of the new parent volume, continuing to use the current cutting mode; when the similarity is less than or equal to the preset threshold, or the current cutting mode is not feasible for the restricted area interval of the new parent volume, selecting a cutting mode feasible for the restricted area interval of the new parent volume from the feasible modes as the new cutting mode and triggering a tool-changing operation, updating the current cutting mode to the new cutting mode, and updating the restricted area features corresponding to the current cutting mode to the restricted area interval of the new parent volume.

[0033] Specifically, the implementation process of this embodiment includes: Real-time splitting decision and dynamic pattern maintenance: The master roll immediately enters the slitting process after it leaves the machine. The system uses a dynamic mode maintenance strategy for real-time decision-making. 1) The system maintains the current cutting mode P. curr and its corresponding restricted area feature F curr .

[0034] 2) When the new parent volume arrives, obtain its restricted area F. new Calculate F new With F curr The similarity is determined based on whether the deviation of the center position of the restricted area is less than a preset threshold, or whether the overlap of the restricted area intervals is greater than a preset threshold.

[0035] 3) If F new With F curr Similar, and the current pattern P curr For F new If feasible, then the current mode can be used directly for splitting.

[0036] 4) If F new With F curr If the patterns are dissimilar, or the current pattern is not feasible, then a pair F is selected or generated from the set of feasible patterns. new A feasible new model P newThis triggers a tool change operation, switching the slitting machine to a new mode and updating P. curr =P new F curr =F new .

[0037] Furthermore, the process of allocating cutting modes to each master roll includes: selecting a target cutting mode from the feasible modes, and establishing an integer programming model with the number of cutter changes and paper edge waste as optimization objectives; the integer programming model uses the number of times each cutting mode is used as a decision variable, the feasibility of the cutting mode allocated to each master roll within its restricted area as a constraint, and the requirement that the output of all master rolls meets the order demand as a constraint; solving the integer programming model, determining the number of times each cutting mode is used based on the solution results, and allocating cutting modes sequentially according to the arrival order of each master roll, with different cutting modes between adjacent master rolls counted as one cutter change.

[0038] Specifically, the implementation process of this embodiment includes: Select target cutting mode: The target cutting mode is selected from the filtered feasible modes. The optimization objective of the selected target cutting mode includes at least one of the following: minimizing the number of blade changes; minimizing paper scrap; and minimizing production costs, wherein the production costs include at least one of paper scrap costs, blade change costs, and inventory costs.

[0039] The target cutting pattern can be selected using integer programming or heuristic algorithms. When using integer programming, the following optimization model is established: The decision variable is the number of times each cutting pattern is used, x. j (Integer), the objective function is: ; Where G is the total number of parent volumes, g is the parent volume splitting sequence number, and C is the total number of parent volumes. change For the cost of a single tool change, 1 {方案g≠方案g-1} For tool change detection indication function, C trim The cost of waste paper per unit area. j Let x be the area of ​​paper scrap in pattern j. j Let j be the number of times pattern j is used. This objective function is used to minimize the sum of tool change cost and paper scrap cost.

[0040] The constraints include: each master roll must be assigned a cutting pattern that is feasible for its restricted areas; the total output of all master rolls must meet the order requirements: ∑ j a ij x j ≥b i , where a ij b represents the number of product i portions in pattern j. iLet i be the order demand for product i.

[0041] Furthermore, the production scheduling plan will be output, specifically including: Output the production scheduling plan, including the cutting mode, cutting blade position, slitting sequence, blade change time point for each master roll, and a production summary table. The production summary table includes the order demand, planned production quantity, whether it is met, and suggestions for handling the difference for each product. The master roll slitting instruction table (production scheduling plan) is shown in Table 1, and the production summary table is shown in Table 2.

[0042] Table 1 Table 2 Example 2 Based on the same general inventive concept, this invention also provides a paper roll slitting and scheduling optimization system that considers the lateral position of paper defects. The paper roll slitting and scheduling optimization system considering the lateral position of paper defects provided by this invention is described below. The paper roll slitting and scheduling optimization system considering the lateral position of paper defects described below can be referred to in correspondence with the paper roll slitting and scheduling optimization method considering the lateral position of paper defects described above. The system includes: The data acquisition module is used to acquire paper defect detection data and order requirements of the master roll, and determine the restricted area in the width direction of the master roll based on the paper defect detection data; The pattern generation module is used to generate candidate cutting patterns according to the order requirements. Each candidate cutting pattern includes a combination of widths of finished paper rolls and the number of finished paper rolls of each width in the pattern. The feasibility filtering module is used to divide the width of the master roll into an available range according to the restricted range, put the finished paper rolls in the candidate cutting modes into the available range for feasibility judgment, mark the candidate cutting modes that are judged to be feasible as feasible modes, and remove the candidate cutting modes that are not feasible. The real-time decision module is used to maintain the current cutting mode and its corresponding restricted area features. When a new parent volume arrives, it obtains the restricted area of ​​the new parent volume and calculates the similarity with the restricted area features corresponding to the current cutting mode. Based on the similarity judgment result and the feasibility of the current cutting mode for the restricted area of ​​the new parent volume, it determines whether to switch to a new cutting mode. The optimization solution module is used to select a target cutting mode from the feasible modes, assign cutting modes to each master volume, and make the allocation results meet the order requirements. The production scheduling output module is used to output a production scheduling plan, which includes the cutting mode and cutter position for each master roll.

[0043] Example 3 (equivalent to Example 2 above) In this embodiment, a computer terminal device is provided, including: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the steps of the paper roll slitting and scheduling optimization method that takes into account the lateral position of paper defects.

[0044] In this embodiment, a computer-readable storage medium is also provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the above-described paper roll slitting and scheduling optimization method that takes into account the lateral position of paper defects.

[0045] In this embodiment, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps of the above-described paper roll slitting and scheduling optimization method that considers the lateral position of paper defects.

[0046] An application example of this invention is as follows: This embodiment uses the high-speed specialty paper production of a paper mill as an example. The width of the master roll produced by the paper machine is W=4.0m. The slitting machine has 8 cutters, meaning that the total number of finished paper rolls in a single cutting mode does not exceed 7. Paper defect detection data for each master roll is acquired in real time through a paper defect detection system (WIS). In this embodiment, the restricted area is divided into two typical cases: the left restricted area is located near the left edge of the master roll, for example [0,0.3]; the middle restricted area is located in the middle of the master roll, for example [1.9,2.1]. The order requirements for this embodiment are shown in Table 3.

[0047] Table 3 Based on order requirements, a set of candidate cutting patterns is pre-generated. This embodiment uses an enumeration method to generate all possible cutting patterns, with constraints including: the total width of the cutting patterns does not exceed the effective width of the master roll W = 4.0m; the total number of finished paper rolls in a single cutting pattern does not exceed 7. Some candidate cutting patterns are shown in Table 4.

[0048] Table 4 For each master roll, the feasibility of candidate cutting patterns is assessed based on its restricted areas. The core of this feasibility assessment is to divide the master roll width into several usable intervals and determine whether all finished paper rolls in the cutting pattern can be placed within these usable intervals. The specific method is as follows: First, the usable intervals are divided according to the restricted areas. Let the master roll width be W, and the restricted areas be [l1, r1], [l2, r2], ..., [l...]. k ,r kThe usable intervals are [0, l1), (r1, l2), ..., (r... k Then, the finished paper rolls in the cutting mode are arranged in descending order of width, and each roll is placed into the available space in turn. The first available space that can accommodate its width is selected for placement. If all paper rolls can be placed, the mode is feasible; otherwise, it is not. When there are multiple arrangement orders for the same candidate cutting mode, if at least one arrangement order allows all paper rolls to be placed into the available space, the mode is feasible. When the parent roll has no paper defects, the restricted area is an empty set, and the available space is the entire width of the parent roll. At this time, all cutting modes that meet the width and cutter count constraints are feasible. When all candidate cutting modes are marked as infeasible, the system outputs a prompt message indicating that the parent roll cannot be used for the current order and it is recommended to downgrade its use or handle it differently.

[0049] The above process is illustrated below with a specific numerical example. Assume that five parent volumes are reached consecutively, and their restricted areas are shown in Table 5.

[0050] Table 5 Taking Mode 5 (1A+2B) as an example, the following checks are performed on the left restricted area mother roll: The paper roll list is B(1.2), B(1.2), A(0.8), arranged in descending order of width. After placing roll 1 (B) into the usable area, there is 2.5m remaining; after placing roll 2 (B) into the usable area, there is 1.3m remaining; after placing roll 3 (A) into the usable area, there is 0.5m remaining. All paper rolls are successfully placed, therefore Mode 5 is feasible for the left restricted area. The following checks are performed on the middle restricted area mother roll: Roll 1 (B) is placed in the left area, leaving 0.7m remaining; Roll 2 (B) cannot be placed in the left area, but is placed in the right area, leaving 0.7m remaining; Roll 3 (A) cannot be placed in either the left or right area (both leaving 0.7m, less than 0.8m), therefore Mode 5 is not feasible for the middle restricted area.

[0051] In actual production, the master roll immediately enters the slitting process after leaving the machine, and the system uses a dynamic mode maintenance strategy for real-time decision-making. The system maintains the current cutting mode P. curr and its corresponding restricted area feature F curr When the new parent volume arrives, obtain its restricted area F. new Calculate F new With F curr The similarity is determined based on whether the deviation of the center position of the restricted area is less than a preset threshold, or whether the overlap of the restricted area intervals is greater than a preset threshold. If F new With F curr Similar, and the current pattern P curr For F new If feasible, then directly use the current mode for splitting; if F new With F currIf the patterns are dissimilar, or the current pattern is not feasible, then a pair F is selected or generated from the set of feasible patterns. new A feasible new model P new This triggers a tool change operation, switching the slitting machine to a new mode and updating P. curr =P new F curr =F new .

[0052] Using the numerical example above, the system initializes without a current mode. When parent volume 1 arrives, mode 5 is selected, and the initial tool change count is not included in the tool change count. Parent volume 2 has the same restricted area as parent volume 1, so the similarity assessment is similar, and mode 5 is feasible; therefore, mode 5 is used without a tool change. The same applies to parent volume 3. Parent volume 4 has a restricted area of ​​[1.9, 2.1], which is dissimilar to the current restricted area [0, 0.3], and mode 5 is not feasible. The system selects a new mode from the feasible mode set that is feasible for the middle restricted area, triggering a tool change operation and switching to the new mode. Parent volume 5 has the same restricted area as parent volume 4, so the similarity assessment is similar, and the new mode is feasible; therefore, the new mode is used without a tool change. The total number of tool changes during the entire process is 1.

[0053] In actual production, the number of master rolls is large, and order demands are diverse, requiring the system to consider a global optimization objective. The system employs an integer programming model for global optimization, with the decision variable being the number of times each cutting pattern is used (x). j (Integer). The objective function is: ; Where G is the total number of parent volumes, g is the parent volume splitting sequence number, and C is the total number of parent volumes. change For the cost of a single tool change, 1 {方案g≠方案g-1} For tool change detection indication function, C trim The cost of waste paper per unit area. j Let x be the area of ​​paper scrap in pattern j. j Let j be the number of times pattern j is used. This objective function is used to minimize the sum of tool change cost and paper scrap cost.

[0054] The constraints include: each master roll must be assigned a cutting pattern that is feasible for its restricted areas; the total output of all master rolls must meet the order requirements: ∑ j a ij x j ≥b i , where a ij b represents the number of product i portions in pattern j. i Let i be the order demand for product i.

[0055] After solving the problem, the system automatically calculates the planned total production volume for each product and compares it with the order demand. For example, assuming the solution result is that mode 5 is repeated x5 times and mode 3 is repeated x3 times, then the planned production volume of product A is 1·x5 + 3·x3, and the planned production volume of product B is 2·x5 + 1·x3. The system outputs a summary table of production volumes as shown in Table 6.

[0056] Table 6 If overproduction occurs, the system will automatically mark the overproduction portion and suggest that it be put into storage as regular inventory.

[0057] The final production schedule includes the cutting mode, cutter position, slitting sequence, cutter change time for each master roll, and the aforementioned production summary table. Slitting machine operators execute cutter scheduling and slitting production according to this plan, and warehouse management personnel can decide whether to call upon inventory or arrange supplementary production based on the discrepancy.

[0058] This invention provides a paper roll slitting and scheduling optimization method and system that considers the lateral position of paper defects. By introducing constraints on the lateral position of paper defects during the scheduling stage, and using the restricted area as the basis for judging the feasibility of the cutting mode, this invention ensures that the cutting scheme actively avoids areas with paper defects, preventing paper defects from falling within the finished paper roll width. This significantly reduces the scrap rate of finished products caused by paper defects. Compared with the existing technology that only remedies the situation after the paper defects occur, this invention achieves proactive avoidance of paper defects. Through dynamic pattern maintenance and similarity judgment, this invention only changes the blade when there is a significant change in the restricted area, under the condition of immediate slitting of the mother roll. This avoids frequent blade changes, reduces the burden of manual operation, and improves slitting efficiency. Compared with the existing technology that focuses on the utilization rate of a single raw material and ignores the cost of blade changes, this invention also takes into account the cost of blade changes. This invention is particularly suitable for the production of high-speed specialty papers such as cigarette paper base paper and glassine paper. By actively avoiding paper defects and optimizing the cost of changing blades, it meets the dual requirements of quality and efficiency for high-speed specialty papers and has strong industrial applicability. At the same time, it can be solved accurately using integer programming methods or quickly using heuristic algorithms, adapting to production scheduling scenarios of different scales and constraints.

[0059] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for optimizing paper roll slitting and production scheduling considering the lateral position of paper defects, characterized in that, include: Obtain paper defect detection data of the master roll, and determine the restricted area in the width direction of the master roll based on the paper defect detection data; Candidate cutting patterns are generated based on order requirements. Each candidate cutting pattern includes a combination of widths of finished paper rolls and the number of finished paper rolls of each width in that pattern. The width of the master roll is divided into an available range according to the restricted area. The finished paper rolls in the candidate cutting modes are placed into the available range in turn for feasibility judgment. The candidate cutting modes that are judged to be feasible are marked as feasible modes, and the infeasible candidate cutting modes are eliminated. The system maintains the current cutting mode and its corresponding restricted area features. When a new master volume arrives, the restricted area of ​​the new master volume is obtained and the similarity with the restricted area features corresponding to the current cutting mode is calculated. Based on the similarity judgment result and the feasibility of the current cutting mode for the restricted area of ​​the new master volume, it is determined whether to switch to a new cutting mode. Select the target cutting mode from the feasible modes, and assign the cutting mode to each master volume so that the allocation result meets the order requirements; Output a production scheduling plan, which includes the cutting mode and cutter position for each master roll.

2. The method according to claim 1, characterized in that, The process of determining the restricted area includes: when there are multiple paper defects in the mother roll, the horizontal position of each paper defect in the width direction of the mother roll is represented as an interval, and the set of all intervals is the restricted area, which is the union of multiple discontinuous intervals.

3. The method according to claim 1, characterized in that, The feasibility assessment process includes: dividing the width of the master roll into usable intervals according to the restricted area; arranging the finished paper rolls in the candidate cutting modes in descending order of width; attempting to place each finished paper roll into the usable intervals in the order of arrangement, and selecting the first usable interval that can accommodate the width of the finished paper roll; when all the finished paper rolls in the candidate cutting modes can be placed into the usable intervals, the candidate cutting mode is marked as a feasible mode, otherwise it is marked as an infeasible mode.

4. The method according to claim 3, characterized in that, When there are multiple arrangement orders for finished paper rolls within the available range in the same candidate cutting mode, the feasibility judgment process includes: trying various arrangement orders in turn, and when there is at least one arrangement order that allows all finished paper rolls in the candidate cutting mode to be placed in the available range, the candidate cutting mode is marked as a feasible mode.

5. The method according to claim 1, characterized in that, The process of determining whether to switch to a new cutting mode includes: the system maintaining the current cutting mode and its corresponding restricted area features; when a new parent volume arrives, obtaining the restricted area of ​​the new parent volume, and calculating the similarity between the restricted area of ​​the new parent volume and the restricted area features corresponding to the current cutting mode; when the similarity is greater than a preset threshold and the current cutting mode is feasible for the restricted area of ​​the new parent volume, the current cutting mode continues to be used; when the similarity is less than or equal to the preset threshold, or the current cutting mode is not feasible for the restricted area of ​​the new parent volume, a cutting mode feasible for the restricted area of ​​the new parent volume is selected from the feasible modes as the new cutting mode and a tool-changing operation is triggered, updating the current cutting mode to the new cutting mode, and updating the restricted area features corresponding to the current cutting mode to the restricted area of ​​the new parent volume.

6. The method according to claim 1, characterized in that, The process of assigning cutting modes to each master roll includes: selecting a target cutting mode from the feasible modes, and establishing an integer programming model with the number of cutter changes and paper edge waste as optimization objectives; the integer programming model uses the number of times each cutting mode is used as a decision variable, the feasibility of the cutting mode assigned to each master roll within its restricted area as a constraint, and the requirement that the output of all master rolls meets the order demand as a constraint; solving the integer programming model, determining the number of times each cutting mode is used based on the solution results, and assigning cutting modes sequentially according to the arrival order of each master roll, with different cutting modes between adjacent master rolls counted as one cutter change.

7. A paper roll slitting and scheduling optimization system considering the lateral position of paper defects, characterized in that, The system for implementing the method of any one of claims 1-6 comprises: The data acquisition module is used to acquire paper defect detection data and order requirements of the master roll, and determine the restricted area in the width direction of the master roll based on the paper defect detection data; The pattern generation module is used to generate candidate cutting patterns according to the order requirements. Each candidate cutting pattern includes a combination of widths of finished paper rolls and the number of finished paper rolls of each width in the pattern. The feasibility filtering module is used to divide the width of the master roll into an available range according to the restricted range, put the finished paper rolls in the candidate cutting modes into the available range for feasibility judgment, mark the candidate cutting modes that are judged to be feasible as feasible modes, and remove the candidate cutting modes that are not feasible. The real-time decision module is used to maintain the current cutting mode and its corresponding restricted area features. When a new parent volume arrives, it obtains the restricted area of ​​the new parent volume and calculates the similarity with the restricted area features corresponding to the current cutting mode. Based on the similarity judgment result and the feasibility of the current cutting mode for the restricted area of ​​the new parent volume, it determines whether to switch to a new cutting mode. The optimization solution module is used to select a target cutting mode from the feasible modes, assign cutting modes to each master volume, and make the allocation results meet the order requirements. The production scheduling output module is used to output a production scheduling plan, which includes the cutting mode and cutter position for each master roll.

8. A computer terminal device, characterized in that, include: One or more processors; A memory, coupled to the processor, for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors perform the steps of the method as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-6.

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