Packaging structure scheme optimization method and system based on multi-objective decision

Abstract

This invention discloses a method and system for optimizing packaging structure schemes based on multi-objective decision-making, belonging to the field of packaging design optimization technology. The method includes: S1, acquiring the packaging die-cutting diagram and folding parameters, simulating step-by-step folding, and generating folding contact anchor chains, defect anchor sequence, and candidate structural modifications; S2, applying two modifications to the same defect anchor in reverse order, generating a dual-order modified structure and anchor locking state, and filtering available modifications; S3, eliminating burden transfer modifications based on changes in contact normal force and intrusion depth, revoking and expanding each modification to generate first-level rectification, second-level performance improvement, and third-level alternative candidate sequences; S4, calculating the target margin value, filtering graded schemes, updating the die-cutting diagram, and outputting an editable optimized die-cutting diagram after verification by the folding contact anchor chain. This solves the problems in existing packaging structure optimization, such as difficulty in identifying the mutual influence between folding defects, leading to easy contact burden transfer caused by local modifications, a single candidate scheme, and insufficient reliability of die-cutting optimization.

Description

Technical Field

[0001] This invention relates to the field of packaging design optimization technology, specifically to a method and system for optimizing packaging structure schemes based on multi-objective decision-making. Background Technology

[0002] With the development of digital packaging design, 3D folding simulation and multi-objective decision-making technologies, packaging structure solutions are gradually shifting from manual experience-based design to automatic generation and optimization based on die data, product parameters and packaging performance indicators. Related technologies are now able to calculate, evaluate and select candidate solutions based on packaging form, logistics costs, material properties and packaging effect.

[0003] For example, application CN121809754A discloses a method for generating a transformer core packaging and transportation scheme, including the following steps: obtaining a task order and storing the task order in a preset temporary library; generating an initial scheme, several optimized schemes, and several consolidation schemes based on preset triggering conditions and the task order in the temporary library, each sub-scheme containing corresponding packaging information and logistics information; calculating the comprehensive score of the initial scheme, optimized schemes, and consolidation schemes respectively; and selecting the scheme with the highest comprehensive score as the optimal scheme.

[0004] For example, application CN120893631B discloses a machine learning-based intelligent active packaging optimization method and system. This includes: periodically detecting and recording the activity parameters of the target active food based on a test plan, constructing a detection parameter matrix, introducing a CNN model for matrix feature learning and characterizing parameter change patterns, calculating the first qualitative change coefficient using an ideal state matrix, fitting and predicting the qualitative change coefficient, introducing ideal activity parameters to evaluate the second qualitative change coefficient, and optimizing the fitting and prediction process. Finally, the packaging effect is evaluated based on the fitting results, and changes in food activity are predicted, thereby achieving precise optimization of the preset packaging test plan.

[0005] However, existing technologies mainly focus on comprehensively evaluating the complete packaging solution or predicting the packaging effect based on detection parameters. They do not establish the correlation between the first contact points in the step-by-step folding process of the packaging structure, and it is difficult to identify the mutual influence of multiple structural modifications corresponding to the same defect anchor point under different execution sequences. After local modifications eliminate the original defect, they may also transfer the contact normal force and contact intrusion to subsequent folding positions. Furthermore, there is a lack of a graded generation mechanism for rectification, performance improvement and template replacement solutions, as well as a die-cutting mold re-inspection mechanism.

[0006] Therefore, in order to address the above problems, there is an urgent need to provide a method and system for optimizing packaging structure schemes based on multi-objective decision-making. Summary of the Invention

[0007] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a method and system for optimizing packaging structure schemes based on multi-objective decision-making. This solves the problems in existing packaging structure optimization, such as the difficulty in identifying the mutual influence between folding defects, which leads to local modifications easily causing contact burden transfer, limited candidate schemes, and insufficient reliability of die-cutting optimization.

[0008] Technical solution To achieve the above objectives, the present invention provides the following technical solution: a packaging structure optimization method based on multi-objective decision-making, comprising: S1, obtaining a reference packaging die drawing, packaging folding parameters, and allowable parameters of the packaging structure; simulating the step-by-step folding of packaging structure units; determining the position where non-directly connected packaging structure units first make surface contact as the first contact point and connecting them to form a folding contact anchor chain; calculating the defect normalization value based on the first contact point and generating an original defect anchor sequence; and generating candidate structure modifications based on the original defect anchors; S2, applying two candidate structure modifications in reverse order to the same original defect anchor, generating a positive double-modification structure and a reverse double-modification structure. S3. Modify the structure and corresponding anchor locking status, and select the structural modifications to be retained; S4. Based on the changes in contact normal force and contact intrusion depth, remove contact burden transfer modifications from the retained structural modifications, form candidate contact closure sequences based on the remaining retained structural modifications and cancel them one by one, generate a first-level rectification candidate sequence, and generate a second-level performance improvement candidate sequence and a third-level replacement candidate sequence based on the remaining retained structural modifications and packaging structure template; S5. Calculate the target margin value of each level of candidate sequence, select the first-level rectification scheme, the second-level improvement scheme and the third-level replacement scheme, update the corresponding die-cutting diagram, and output the graded optimization scheme and editable optimized packaging die-cutting diagram after verification by folding contact anchor chain.

[0009] Further, the following steps are taken to obtain the benchmark packaging die drawing, packaging folding parameters, and allowable parameters of the packaging structure, simulate the step-by-step folding of packaging structure units, and determine the position where the first surface contact occurs between non-directly connected packaging structure units as the first contact point and connect them to form a folding contact anchor chain: Obtain the benchmark packaging die drawing, packaging material parameters, product external dimensions, product weight, packaging folding sequence, target angle value of the crease line, folding angle sampling step size, minimum adjustment amount of the die-cutting position, and allowable parameters of the packaging structure; extract the cutting line, crease line, window boundary line, and adhesive area boundary line; divide the packaging structure units according to the closed area enclosed by the cutting line, and determine the outline edge number of the packaging structure unit; control the active packaging structure unit to rotate step-by-step around the corresponding crease line according to the packaging folding sequence, with each rotation forming a fold... The sampling step size of the folding angle is used to calculate the minimum surface distance between the active packaging structural unit and all packaging structural units except those directly connected to the current indentation line. When the current minimum surface distance is not greater than zero and the previous minimum surface distance is greater than zero, linear interpolation is performed on the two minimum surface distances and the two folding angles to obtain the first contact angle value. The midpoint of the two surface points with the smallest distance under the first contact angle is determined as the first contact point. The first contact points are arranged according to the folding stage number and the first contact angle value. When the active packaging structural unit numbers of two adjacent first contact points are the same, and the two first contact points correspond to the same contour edge number after being projected onto the contour of the active packaging structural unit, or the corresponding contour edges have a common endpoint, the two adjacent first contact points are connected to form a folding contact anchor chain.

[0010] Further, based on the initial contact point, the defect normalization value is calculated and the original defect anchor sequence is generated. The specific steps for generating candidate structure modifications based on the original defect anchors are as follows: Calculate the effective overlap length of the tongue, the effective overlap area of ​​the lock bottom piece, the effective bonding width of the adhesive area, and the contact intrusion depth of the non-connected packaging structure unit under the folded state corresponding to each initial contact point; subtract the effective overlap length of the tongue, the effective overlap area of ​​the lock bottom piece, the effective bonding width of the adhesive area, and the contact intrusion depth of the non-connected packaging structure unit from the lower limit of the overlap length, and then divide each of these values ​​by the corresponding allowable parameters to obtain the four types of defect normalization values; determine each positive defect normalization value, the corresponding initial contact point, and the defect type as an original defect. The anchor positions are identified, and an original defect anchor position sequence is generated in ascending order of folding stage number and descending order of defect normalization value. For each original defect anchor position, candidate structure modifications are generated based on the defect type and contour edge number corresponding to the original defect anchor position. When the defect type is insufficient tongue overlap, the free end boundary of the tongue is moved along the insertion direction. When the defect type is insufficient lock bottom overlap, the free end boundary of the folded lock bottom piece is moved along the overlap direction. When the defect type is insufficient adhesive bonding, the outer boundary of the adhesive area is moved along the width direction. When the defect type is excessive contact intrusion, the free end boundary of the intrusion is moved in the opposite direction of the first contact point normal. Candidate structure modifications are generated with the minimum adjustment amount of the die-cutting position as the step size, and candidate structure modifications that cause cutting line intersection, packaging structure unit contour breakage, and indentation line entering the window area are deleted.

[0011] Furthermore, the specific steps for applying two candidate structural modifications in reverse order to the same original defect anchor position to generate a positive double-modification structure, a reverse double-modification structure, and the corresponding anchor position locking state are as follows: When the two candidate structural modifications correspond to the same original defect anchor position, and the two candidate structural modifications are applied to packaging structure units on both sides of the original defect anchor position or to different boundaries of the same packaging structure unit, the two candidate structural modifications are grouped into a candidate modification pair; the two candidate structural modifications are respectively designated as the first candidate structural modification and the second candidate structural modification, and applied separately to the same reference packaging structure to generate the first single-modification structure and the second single-modification structure; after applying the first candidate structural modification, the folded contact anchor chain is regenerated, and the updated first contact point is selected that contains the same two packaging structure units as the original defect anchor position and has the smallest absolute value of the first contact angle difference; the updated first contact point is calculated. The arc length ratio of the second contact point on the corresponding contour edge is used to move the application point of the second candidate structure modification to a position with the same arc length ratio in the updated contour edge. The angle between the modification direction and the outward normal of the updated contour edge remains unchanged. The second candidate structure modification is applied according to the original parameter change to generate a positive double modification structure. The same operation is performed in reverse order to generate a negative double modification structure. The original arc length ratio of the original defect anchor on the corresponding contour edge of the two packaging structure units is read. Two material points with the same original arc length ratio are selected in the positive double modification structure and the negative double modification structure, respectively. In the independent folding simulation copy, the midpoint of the two material points is constrained to coincide with the original defect anchor, and the normal angle of the surfaces where the two material points are located is constrained to be equal to the normal angle when the reference packaging structure first contacts, to obtain the positive anchor locking state and the negative anchor locking state.

[0012] Further, the specific steps for selecting and retaining structure modifications are as follows: Calculate the original defect normalization value of the first single modification structure, the second single modification structure, the forward double modification structure, the reverse double modification structure, the forward anchor locking state, and the reverse anchor locking state; when the original defect normalization value of the first single modification structure is not greater than zero, write the first candidate structure modification into the retained structure modification set; when the original defect normalization value of the second single modification structure is not greater than zero, write the second candidate structure modification into the retained structure modification set; when the original defect normalization values ​​of both the first and second single modification structures are greater than zero, and the original defect normalization values ​​of the forward double modification structure and the forward anchor locking state are not greater than zero, write the candidate modification pair and the forward execution order into the retained structure modification set; when the original defect normalization values ​​of both the first and second single modification structures are greater than zero, and the original defect normalization values ​​of the reverse double modification structure and the reverse anchor locking state are not greater than zero, write the candidate modification pair and the reverse execution order into the retained structure modification set.

[0013] Furthermore, based on the changes in contact normal force and contact intrusion depth, the contact burden transfer modification is eliminated from the retained structure modifications. Based on the remaining retained structure modifications, a candidate contact closure sequence is formed and then cancelled item by item. The specific steps for generating the first-level rectification candidate sequence are as follows: For individual modifications and candidate modification pairs in the retained structure modification set, folded contact anchor chains are regenerated. The contact normal force value before modification of the original defect anchor position is subtracted from the modified contact normal force value to obtain the contact normal force reduction value. For the first contact point after the original defect anchor position that contains any corresponding packaging structure unit number, the difference between the modified and unmodified contact normal force and the difference in contact intrusion depth are calculated to obtain the contact normal force increase value and the contact intrusion depth increase value. The contact normal force reduction value is greater than zero, the sum of all positive contact normal force increase values ​​is not less than the contact normal force reduction value, and any contact... When the increase in intrusion depth is greater than zero, delete the corresponding single modification or candidate modification pair; according to the original defect anchor sequence, apply a single modification or candidate modification pair that has not been deleted to the current original defect anchor; if the defect normalization value of the current original defect anchor is not greater than zero after application, and no new defect anchor is generated with a folding stage number not greater than the folding stage number of the current original defect anchor, continue processing the next original defect anchor until all defect normalization values ​​are not greater than zero, forming a candidate contact closure sequence; revoke the single modifications or candidate modification pairs in the candidate contact closure sequence item by item from back to front according to the execution order; if there is a defect normalization value greater than zero after revocation or any retained modification meets the deletion condition of the contact burden transfer modification again, restore the corresponding modification; otherwise, delete the corresponding modification. After all revocations are completed, a first-level rectification candidate sequence is generated.

[0014] Furthermore, the specific steps for generating secondary performance improvement candidate sequences and tertiary replacement candidate sequences based on the remaining retained structure modifications and packaging structure templates are as follows: For each primary rectification candidate sequence, an unadopted retained structure modification is added; when all defect normalization values ​​are still not greater than zero after adding, no contact burden transfer occurs, at least one target margin value increases and the remaining target margin values ​​do not decrease, a secondary performance improvement candidate sequence is generated; when there is no primary rectification candidate sequence where all four target margin values ​​are not less than zero, parametric die-cutting drawings with product external dimensions and product weight values ​​within the applicable range are selected from the packaging structure template, and the internal dimensions of the packaging and the positions of the tongue, slot, adhesive edge, locking bottom piece and indentation line are adjusted according to the product external dimensions and the lower limit of clearance, the folded contact anchor chain is regenerated and the defect normalization value is calculated to generate a tertiary replacement candidate sequence.

[0015] Further, the specific steps for calculating the target margin values ​​of candidate sequences at each level and screening the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan are as follows: Calculate the target margin values ​​for each level of candidate sequences. The target margin values ​​include structural safety margin, remaining material cost, remaining production time, and operational margin. Delete any candidate sequence with a target margin value less than zero. Arrange the candidate sequences at each level in descending order according to the minimum value among the target margin values. Determine the first position in each level as the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan.

[0016] Further, the specific steps for updating the corresponding die-cutting diagram and outputting the graded optimization scheme and editable optimized packaging die-cutting diagram after verification by folded contact anchor chain are as follows: Update the baseline packaging die-cutting diagram according to the first-level rectification scheme and the second-level improvement scheme, and update the parameterized die-cutting diagram according to the third-level alternative scheme. Mark the modified boundary and parameter change in the updated die-cutting diagram to generate the corresponding optimized packaging die-cutting diagram; reread each optimized packaging die-cutting diagram, generate the folded contact anchor chain, and recalculate the defect normalization value and target margin value; when the first-level rectification scheme and the second-level improvement scheme do not show contact burden transfer, all defect normalization values ​​are not greater than zero, and all target margin values ​​are not less than zero, output the corresponding graded optimization scheme and editable optimized packaging die-cutting diagram; when all defect normalization values ​​of the third-level alternative scheme are not greater than zero and all target margin values ​​are not less than zero, output the third-level alternative scheme and editable optimized packaging die-cutting diagram; if any condition is not met, delete the corresponding scheme and read the next sorting result at the same level.

[0017] The second aspect of this invention provides a packaging structure optimization system based on multi-objective decision-making, comprising: a folding anchor chain generation module, used to acquire a reference packaging die drawing, packaging folding parameters, and allowable parameters of the packaging structure; simulate the step-by-step folding of packaging structure units; determine the position where non-directly connected packaging structure units first make surface contact as the first contact point and connect them to form a folding contact anchor chain; calculate the defect normalization value based on the first contact point and generate an original defect anchor sequence; and generate candidate structure modifications based on the original defect anchors; and a dual-order anchor solution module, used to apply two candidate structure modifications in reverse order to the same original defect anchor, generating a forward dual-modification structure, a reverse dual-modification structure, and corresponding... The anchor position is locked, and structural modifications are selected and retained. The closed-level generation module is used to eliminate contact burden transfer modifications from the retained structural modifications based on changes in contact normal force and contact intrusion depth. Based on the remaining retained structural modifications, candidate contact closure sequences are formed and canceled one by one, generating a first-level rectification candidate sequence. Based on the remaining retained structural modifications and packaging structure template, second-level performance improvement candidate sequences and third-level replacement candidate sequences are generated. The hierarchical decision write-back module is used to calculate the target margin values ​​of each level of candidate sequences, select first-level rectification schemes, second-level improvement schemes and third-level replacement schemes, update the corresponding die-cutting diagrams, and output hierarchical optimization schemes and editable optimized packaging die-cutting diagrams after verification by folded contact anchor chains.

[0018] Beneficial effects The present invention has the following beneficial effects: (1) A method and system for optimizing packaging structure schemes based on multi-objective decision-making, by simulating the packaging structure unit to fold step by step and connecting the first contact point to form a folding contact anchor chain, establishes a continuous correlation between the contact position, contact sequence and defect type generated by the packaging structure at different folding stages, so that the original defect anchor can be accurately located according to the folding stage, thereby improving the integrity and traceability of packaging structure defect identification.

[0019] (2) The packaging structure optimization method and system based on multi-objective decision-making can identify the structural coupling differences caused by the modification order by performing forward and reverse double-order application on two candidate structure modifications corresponding to the same original defect anchor position and filtering them in combination with the anchor position locking state, thereby eliminating invalid modifications formed by defect anchor position migration and enhancing the authenticity and feasibility of candidate structure modifications.

[0020] (3) A packaging structure optimization method and system based on multi-objective decision-making, by comparing the changes in contact normal force and contact intrusion depth between the original defect anchor position and the subsequent first contact point, eliminates structural modifications that transfer the local contact burden to the subsequent folding position, and retains necessary modifications by canceling each item, so that the first-level rectification candidate sequence can reduce new interference and redundant modifications while eliminating the original defects.

[0021] (4) A packaging structure optimization method and system based on multi-objective decision-making generates a first-level rectification candidate sequence, a second-level performance improvement candidate sequence and a third-level replacement candidate sequence, and performs hierarchical screening based on the target margin values ​​corresponding to structural safety, material cost, production time and usage operation. Then, the optimized packaging die drawing is output after the folding contact anchor chain is re-inspected. This makes the packaging structure optimization take into account defect rectification, performance improvement and structural replacement, and improves the adaptability, reliability and engineering application value of the optimization scheme. Attached Figure Description

[0022] Figure 1 A flowchart illustrating a packaging structure optimization method based on multi-objective decision-making; Figure 2 A schematic diagram illustrating the screening and contact burden transfer in packaging structure modifications; Figure 3 A schematic diagram illustrating the graded optimization of packaging structure and the verification of target margins; Figure 4 Optimize the system structure diagram for packaging structure schemes based on multi-objective decision-making. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-4This invention provides a technical solution: a packaging structure optimization method based on multi-objective decision-making, comprising: S1, acquiring a reference packaging die drawing, packaging folding parameters, and allowable parameters of the packaging structure; simulating the step-by-step folding of packaging structure units; determining the position where non-directly connected packaging structure units first make surface contact as the first contact point and connecting them to form a folding contact anchor chain; calculating the defect normalization value based on the first contact point and generating an original defect anchor sequence; and generating candidate structure modifications based on the original defect anchors; S2, applying two candidate structure modifications in reverse order to the same original defect anchor, generating a positive double-modification structure and a negative double-modification structure. S3. Based on the changes in contact normal force and contact intrusion depth, remove contact burden transfer modifications from the retained structural modifications. Based on the remaining retained structural modifications, form a candidate contact closure sequence and cancel each one, generating a first-level rectification candidate sequence. Based on the remaining retained structural modifications and packaging structure template, generate a second-level performance improvement candidate sequence and a third-level replacement candidate sequence. S4. Calculate the target margin value of each level of candidate sequence, select the first-level rectification scheme, the second-level improvement scheme and the third-level replacement scheme, update the corresponding die-cutting diagram, and output the graded optimization scheme and editable optimized packaging die-cutting diagram after verification by folding contact anchor chain.

[0025] Specifically, the steps for obtaining the benchmark packaging die-cutting drawing, packaging folding parameters, and allowable packaging structure parameters, simulating the step-by-step folding of packaging structure units, and determining the first contact point as the location where non-directly connected packaging structure units first make surface contact to form a folding contact anchor chain are as follows: Obtain the benchmark packaging die-cutting drawing, packaging material parameters, product dimensions, product weight, packaging folding sequence, indentation line target angle value, folding angle sampling step size, minimum adjustment amount for die-cutting position, and allowable packaging structure parameters. In practice, the benchmark packaging die-cutting drawing in DXF format is read from the packaging design database, including the drawing unit, layer name, line segment endpoint coordinates, arc center coordinates, and arc half-length. The coordinate system includes the diameter value, the start and end angles of the arc, and the closed path markings. Using the lower left corner of the baseline packaging die drawing as the origin, the X-axis is defined as the horizontal direction to the right, the Y-axis as the vertical direction upwards, and the Z-axis as the direction from the normal of the unfolded cardboard surface towards the outside of the packaging. All geometric coordinates in the baseline packaging die drawing are then uniformly transformed to this coordinate system. Packaging material parameters are read from the cardboard material parameter table. These parameters include at least the cardboard thickness, elastic modulus, Poisson's ratio, bending stiffness, and surface friction coefficient. The cardboard thickness can range from 0.8 mm to 4.5 mm, and the elastic modulus can range from 150 MPa to 1200 MPa. The specific values ​​are determined based on the compression test records and bending test records of the same batch of cardboard; the product's external dimensions are read from the bounding box data of the product's 3D model. If the product's 3D model is missing, a coordinate measuring machine is used to collect the product's length, width, and height values. The product's weight is collected by an electronic scale with a resolution of no more than 1g; the packaging folding sequence and the target angle value of the crease line are read from the packaging process card, and the target angle value of each crease line is limited to the range of 0° to 180°; the folding angle sampling step can be 1° to 5°, and the folding angle sampling step is determined based on the minimum crease line rotation radius value and the collision detection accuracy. The smaller the minimum crease line rotation radius value, the smaller the folding angle sampling step. The minimum adjustment range for the die-cutting position can be 0.1mm to 0.5mm. The minimum adjustment range for the die-cutting position is determined based on the positioning accuracy of the die-cutting machine, the cutting accuracy of the cutter line, and the springback error of the cardboard. The allowable parameters of the packaging structure can be read from the packaging structure parameter table. The allowable parameters of the packaging structure include at least the lower limit of the tongue overlap length, the lower limit of the bottom lock overlap area, the lower limit of the adhesive bonding width, the upper limit of the contact penetration depth, the allowable stress value of the structure, the upper limit of the material cost, the upper limit of the production time, the upper limit of the tongue insertion force, the upper limit of the packaging opening operation force, the upper limit of the bottom lock closing operation force, and the lower limit of the product removal clearance. The allowable parameters of the packaging structure are determined based on the product protection requirements, the performance of the cardboard material, and the packaging production process.Extracting cutting lines, indentation lines, window opening boundary lines, and bonding area boundary lines: In practice, first identify the cutting lines, indentation lines, window opening boundary lines, and bonding area boundary lines based on the layer names in the baseline packaging die drawing. If the layer name is missing, identification is completed based on the line type code value, line width value, closed path marker, and area fill marker. For adjacent line segments whose endpoint distance is no greater than the endpoint closure tolerance value, perform endpoint snapping. The endpoint closure tolerance value can be taken as 0.05mm to 0.20mm. Generate contour paths according to the line segment connection order. During the extraction process, delete isolated line segments with a length less than the minimum effective line length value, which can be taken as 0.10mm to 0.50mm. For duplicate line segments, delete them according to their endpoints. Coordinate values ​​and line segment length values ​​are merged; packaging structure units are divided according to the closed area enclosed by the cutting lines, and the outline edge numbers of the packaging structure units are determined; in specific implementation, each closed path is uniformly processed in a clockwise direction, the interior of the closed path is determined as a packaging structure unit, the indentation line connecting two packaging structure units is recorded as the folding connection edge between the corresponding packaging structure units, and the outline edge numbers are generated sequentially in a clockwise direction from the starting point of the closed path; each packaging structure unit records the packaging structure unit number, outline edge number sequence, indentation line number sequence, boundary point coordinate value sequence, and adjacent packaging structure unit number sequence, thereby establishing the folding connection relationship between packaging structure units; according to the packaging folding... The stacking sequence control mechanism rotates the active packaging structural units step-by-step around the corresponding crease lines. In practice, packaging structural units not currently involved in the folding action are kept in their current spatial positions. The two endpoints of the current crease line are defined as the rotation axis. Each contour point and surface grid point on the active packaging structural unit undergoes rigid body rotation around the rotation axis, with the rotation angle gradually increasing from the initial angle value to the target rotation angle value of the crease line. In the rotation calculation, the cardboard thickness value is extended to both sides along the surface normal of the packaging structural unit by half the cardboard thickness, generating a packaging structural unit surface with actual thickness, avoiding false penetration caused by calculating only a zero-thickness plane. For each folding angle, a sampling step size is used to calculate the relationship between the active packaging structural unit and the folding sequence. The minimum surface distance between packaging structural units other than those directly connected by the front indentation line; in specific implementation, the surface of each packaging structural unit is discretized into triangular facets, and a bounding box hierarchy is established. First, the bounding box hierarchy is used to exclude spatially non-intersecting triangular facet combinations, and then the point-to-face distance, edge-to-edge distance, and face-to-face penetration depth between the remaining triangular facet combinations are calculated. When no penetration occurs, the minimum value among the point-to-face distance and edge-to-edge distance is recorded as the positive minimum surface distance value. When there is just contact, the minimum surface distance value is recorded as zero. When penetration occurs, the maximum value among the face-to-face penetration depths is negative and recorded as the minimum surface distance value. The absolute value of the negative value represents the contact penetration depth.When the current minimum surface distance value is not greater than zero and the previous minimum surface distance value is greater than zero, linear interpolation is performed on the two minimum surface distance values ​​and the two folding angles to obtain the first contact angle value. Specifically, the previous folding angle value is added to the ratio of the previous minimum surface distance value to the difference between the previous minimum surface distance value and the current minimum surface distance value, multiplied by the difference between the current folding angle value and the previous folding angle value to obtain the first contact angle value. Linear interpolation uses the sign change of the minimum surface distance values ​​under adjacent folding sampling states to locate the zero-distance position, which can improve the calculation accuracy of the first contact angle value without further reducing the folding angle sampling step size. The midpoint of the two surface points with the smallest distance under the first contact angle is determined as the first contact point. In practice, the pose of the active packaging structure unit is recalculated according to the first contact angle value. The first and second surface points with the smallest distance are determined from all candidate triangular facet combinations. The average three-dimensional coordinates of the first and second surface points are calculated, and the average three-dimensional coordinates are written into the first contact angle. The coordinates of the contact points are recorded, along with the corresponding folding stage number, initial contact angle value, active packaging structural unit number, contacted packaging structural unit number, contour edge number of the first surface point, and contour edge number of the second surface point. When multiple minimum distance point combinations exist in the same folding stage, these combinations are arranged in ascending order of X and Y coordinate values ​​of the initial contact point, and each combination generates an initial contact point. The initial contact points are arranged according to the folding stage number and the initial contact angle value. In practice, the initial contact points are first arranged in ascending order of folding stage number, then in ascending order of initial contact angle value when the folding stage numbers are the same, and finally in ascending order of active packaging structural unit number when the initial contact angle values ​​are the same, forming an ordered sequence of initial contact points. When two adjacent initial contact points have the same active packaging structural unit number, and the two initial contact points correspond to the same contour edge number after being projected onto the contour of the active packaging structural unit, or when the corresponding contour edges have a common endpoint, the two adjacent initial contact points are connected to form a folding contact anchor chain. In practice, the initial contact point is projected onto the contour of the movable packaging structural unit along the surface normal of the movable packaging structural unit. When the projection point is within the contour edge segment, the corresponding contour edge number is recorded; when the projection point is outside the contour edge segment, the nearest contour endpoint is determined as the projection position. When two initial contact points correspond to the same contour edge number, a directed connection is established according to the arc length ratio of the two initial contact points on the contour edge. When two initial contact points have a common endpoint on the corresponding contour edge, a directed connection is established according to the contour continuity relationship at the common endpoint. Each directed connection is generated in ascending order of the folding stage number. The chain nodes in the folding contact anchor chain record the coordinates of the initial contact point, the initial contact angle, the movable packaging structural unit number, the contacted packaging structural unit number, and the contour edge number. The chain edge records the preceding and following chain node numbers and the folding stage connection relationship, thereby organizing the initial contact positions scattered across different folding stages into a continuously traceable contact evolution path.

[0026] In this implementation scheme, the geometric boundaries, packaging folding sequence, packaging material parameters, and allowable parameters of the packaging structure in the benchmark packaging die drawing are uniformly mapped to the packaging die coordinate system. The first contact point and the connection relationship of the contour edge are continuously tracked in the step-by-step folding state with the actual cardboard thickness. This enables the folding contact anchor chain to stably characterize the contact evolution path of the packaging structure from the initial unfolded state to the target folded state, reducing the identification deviation caused by zero-thickness modeling, discrete sampling errors, and isolated contact points. This provides continuous, verifiable, and geometrically consistent basic data for subsequent original defect anchor location, candidate structure modification generation, and contact burden transfer judgment.

[0027] Specifically, the steps for calculating the defect normalization value based on the first contact point and generating the original defect anchor sequence, and generating candidate structure modifications based on the original defect anchors are as follows: Calculate the effective overlap length of the tongue, the effective overlap area of ​​the locking plate, the effective bonding width of the adhesive area, and the contact intrusion depth of the non-connected packaging structure unit in the folded state corresponding to each first contact point; in specific implementation, read the folding stage number, the first contact angle value, the active packaging structure unit number, the contacted packaging structure unit number, the coordinate value of the first contact point, the coordinate value of the first surface point, the coordinate value of the second surface point, and the corresponding contour edge number according to the first contact point number. The first surface point is located on the surface of the active packaging structure unit, and the second surface point is located on the surface of the contacted packaging structure unit. The process involves: 1) restoring each active packaging structural unit to its spatial pose corresponding to the initial contact angle value; 2) projecting the free end boundary of the tongue along the insertion direction onto the plane of the slot opening, extracting the overlapping line segment between the tongue projection contour and the effective bearing area of ​​the slot, and determining the length of the overlapping line segment along the insertion direction as the effective overlap length value of the tongue; 3) identifying the rear-folded and front-folded bottom pieces according to the packaging folding sequence, projecting the three-dimensional surfaces of the two bottom pieces onto the closed plane of the bottom, performing polygon intersection on the two projected polygons, and determining the intersection polygons... The area of ​​the polygon is determined as the effective overlapping area of ​​the bottom plate. The bottom plate closure plane is taken as the least squares fitted plane of the receiving surfaces of each bottom plate after the bottom plate structure completes the target corner. The slotted area and the cut area are deducted during the projection process. For the adhesive structure, the boundary of the adhesive area and the surface of the corresponding receiving packaging structure unit are projected onto the adhesive bonding plane. Width sampling lines with a spacing of 1mm to 3mm are established along the length of the adhesive area. The length of each width sampling line within the overlapping range of the adhesive area and the receiving packaging structure unit is calculated, and the minimum value of each line segment length is determined as the effective bonding width value of the adhesive area. The spacing of the width sampling lines is determined according to the minimum width value of the adhesive area and the geometric resolution of the reference packaging die drawing. For non-connected packaging structure units, the movable packaging structure is... The surface of each unit and the surfaces of each packaging structure unit not directly connected through the current indentation line are divided into triangular facets. The combination of triangular facets that have penetrated is read. The outer normal of the active packaging structure unit surface is subtracted from the outer normal of the contacted packaging structure unit surface and then normalized to obtain the first contact point normal. The first contact point normal is corrected according to the vector obtained by subtracting the coordinates of the first surface point from the coordinates of the second surface point, so that the first contact point normal points from the active packaging structure unit to the contacted packaging structure unit. When the magnitude of the difference vector between the two outer normals is less than the lower limit of the normal calculation, the outer normal of the active packaging structure unit surface is used and the direction is corrected in the same way. The lower limit of the normal calculation can be 0.01 to 0.05, and the specific value is determined based on the triangular facet normal calculation error.For triangular facet combinations that have experienced penetration, the facet penetration depth values ​​returned by the collision detection of the triangular facets are negatively evaluated and determined as the corresponding directed distance values. The maximum absolute value among all negative directed distances is determined as the contact intrusion depth value of the non-connected packaging structure unit. The normalized value of the tongue overlap defect is the difference between the lower limit of the overlap length and the effective overlap length of the tongue, divided by the lower limit of the overlap length. The normalized value of the lock bottom overlap defect is the difference between the lower limit of the overlap area and the effective overlap area of ​​the lock bottom piece, divided by the lower limit of the overlap area. The normalized value of the adhesive bonding defect is the difference between the lower limit of the bonding width and the effective bonding width of the adhesive area, divided by the lower limit of the bonding width. The normalized value of the contact intrusion defect is the difference between the contact intrusion depth value of the non-connected packaging structure unit and the upper limit of the intrusion depth, divided by the intrusion depth. The upper limit for depth; the lower limits for overlap length, overlap area, bonding width, and intrusion depth are read from the allowable parameters of the packaging structure. All four allowable parameters must be greater than zero. If any allowable parameter is not greater than zero, the current packaging structure optimization task will stop. The lower limit for overlap length can be 5mm to 15mm, the lower limit for overlap area can be 150mm² to 600mm², the lower limit for bonding width can be 8mm to 20mm, and the upper limit for intrusion depth can be 0.10mm to 0.50mm. The specific values ​​are determined based on the packaging material parameters, product weight, transportation vibration level, and die-cutting processing error. A defect normalization value greater than zero indicates that the corresponding actual value does not meet the allowable parameters of the packaging structure, and a defect normalization value of zero indicates that the corresponding actual value is within the allowable parameters. For boundary conditions, a defect normalized value less than zero indicates that the corresponding actual value has a margin of safety. Each positive defect normalized value, its corresponding first contact point, and defect type are defined as an original defect anchor position. An original defect anchor position sequence is generated in ascending order of folding stage number and descending order of defect normalized value. In specific implementation, an original defect anchor position number is generated for each original defect anchor position, and the first contact point number, folding stage number, first contact angle value, defect type, defect normalized value, active packaging structure unit number, contacted packaging structure unit number, first contact point coordinate value, and contour edge number are written into the original defect anchor position record. When the same first contact point corresponds to multiple positive defect normalized values, multiple original defect anchor positions are generated according to the defect type. During sorting... First, arrange the components according to the folding stage number from smallest to largest. If the folding stage numbers are the same, arrange them according to the defect normalization value from largest to smallest. If the defect normalization values ​​are the same, arrange them according to the first contact angle value from smallest to largest. If the first contact angle values ​​are the same, arrange them according to the original defect anchor number from smallest to largest. For each original defect anchor, generate candidate structure modifications based on the defect type and contour edge number corresponding to the original defect anchor. In specific implementation, the candidate structure modification record is written with the candidate structure modification number, original defect anchor number, function packaging structure unit number, function contour edge number, modification direction vector, parameter change amount, and modified boundary point coordinate value sequence. The reference packaging die drawing is copied as an independent die drawing copy, and a single candidate structure modification is applied to the independent die drawing copy.When the defect type is insufficient tongue overlap, the unit vector pointing from the center point of the tongue root to the center point of the slot opening is determined as the insertion direction, and the free end boundary of the tongue is moved along the insertion direction. The two sides of the tongue extend to the moved free end boundary of the tongue, and the width of the tongue remains unchanged after the movement. When the defect type is insufficient lock bottom overlap, the unit vector pointing from the midpoint of the free end boundary of the rear folded lock bottom piece to the centroid of the projection area of ​​the first folded lock bottom piece is determined as the overlap direction, and the free end boundary of the rear folded lock bottom piece is moved along the overlap direction. The two sides of the lock bottom piece re-intersect with the moved free end boundary to form a closed lock bottom piece outline. When the defect type is insufficient adhesive bonding, the center line of the adhesive area length is oriented towards the outside of the adhesive area. The unit normal of the side is determined as the width direction, and the outer boundary of the bonding area is moved along the width direction while keeping the inner and outer boundaries of the bonding area unchanged. The closed contour of the bonding area is recalculated. When the defect type is excessive contact intrusion, the normal of the first contact point is projected in the opposite direction to the plane of the reference packaging die drawing. When the magnitude of the projection vector is not less than the lower limit of the direction, the normalized projection vector is determined as the adjustment direction of the free end boundary that caused the intrusion. When the magnitude of the projection vector is less than the lower limit of the direction, the vector pointing from the midpoint of the free end boundary that caused the intrusion to the centroid of the projection area of ​​the contacted packaging structural unit is inverted and normalized to obtain the adjustment direction away from the contacted packaging structural unit. The lower limit of the direction can be taken from 0.01 to 0.0. 5. The insertion direction, overlap direction, width direction, and direction away from the contacted packaging structural unit are respectively determined as the positive adjustment directions corresponding to insufficient tongue overlap, insufficient bottom overlap, insufficient adhesive bonding, and excessive contact intrusion. Candidate structural modifications are generated only along the corresponding positive adjustment directions for the four types of defects. The minimum adjustment amount of the die-cutting position is read, and the maximum compensation displacement value of the die-cutting equipment is read from the die-cutting equipment parameter table. The minimum positive distance values ​​from the action contour edge to the non-adjacent cutting line, window boundary, indentation line protection boundary, and the effective extension range boundary of the adjacent contour edge are calculated along the corresponding positive adjustment directions. The indentation line protection boundary is formed by offsetting the indentation line to both sides by the indentation line protection distance, which is read from the die-cutting process parameter table. The effective extension range boundary of adjacent contour edges is the limit position where, after the action contour edge moves, the adjacent contour edge can still intersect with the endpoint of the action contour edge and form a closed contour. The geometric safety interval value is subtracted from each minimum positive distance value. When the difference is less than zero, the difference is corrected to zero. The minimum value among the correction results and the maximum compensation displacement value of the die-cutting equipment is determined as the upper limit of the allowable adjustment range for the corresponding contour edge. The geometric safety interval value can be taken from 0.05mm to 0.20mm, and the specific value is determined based on the coordinate accuracy of the reference packaging die drawing, the die-cutting position error, and the die line processing error. When the upper limit of the allowable adjustment range for the corresponding contour edge is less than the minimum adjustment amount of the die-cutting position, no candidate structure modification corresponding to the current original defect anchor position is generated.When the upper limit of the allowable adjustment range of the corresponding contour edge is not less than the minimum adjustment amount of the die-cutting position, the result of dividing the upper limit of the allowable adjustment range of the corresponding contour edge by the minimum adjustment amount of the die-cutting position and rounding down is determined as the candidate quantity value. Candidate structure modifications are generated sequentially in multiples of the minimum adjustment amount of the die-cutting position, and generation stops when the candidate quantity value is reached. For each candidate structure modification, checks are performed on the intersection points inside non-adjacent cutting lines, the connectivity of the contour edge endpoint adjacency graph, and the intersection of the indentation line and the windowed area. If any check fails, the corresponding candidate structure modification is deleted, and candidate structure modifications that pass all checks are retained.

[0028] In this implementation plan, the effective overlap length of the tongue, the effective overlap area of ​​the locking plate, the effective bonding width of the adhesive area, and the contact intrusion depth of the non-connected packaging structural unit are uniformly converted into defect normalization values ​​with consistent judgment direction. The original defect anchor sequence is used to associate the defect type, folding stage, first contact point, and contour edge number, so that packaging structural defects of different dimensions can be sorted and located under the same evaluation benchmark. At the same time, the geometric integrity constraint retains candidate structural modifications with clear action boundaries, modification directions, and parameter changes, reducing the risk of contour damage and processing infeasibility caused by local boundary adjustments. This provides traceable, comparable, and implementable basic data for subsequent judgments of positive double modification structures, reverse double modification structures, anchor locking status, and contact burden transfer.

[0029] Specifically, the steps for applying two candidate structural modifications in reverse order to the same original defect anchor position to generate a positive double-modification structure, a reverse double-modification structure, and the corresponding anchor position locking state are as follows: Read the candidate structural modification record according to the original defect anchor position number. When the two candidate structural modifications are applied to the packaging structure units on both sides of the original defect anchor position, they form a candidate modification pair. When the two candidate structural modifications are applied to different contour edges of the same packaging structure unit, they also form a candidate modification pair. When the two candidate structural modifications are applied to the same contour edge, they do not form a candidate modification pair. According to the candidate structural modification numbers in ascending order, determine the two candidate structural modifications in the candidate modification pair as the first candidate structural modification and the second candidate structural modification, and then... Do not apply modifications to the same baseline packaging structure alone; instead, generate a first and a second single-modification structure. In practice, copy the baseline packaging structure and its corresponding folding simulation data to create a first and a second independent geometric copy. Apply only the first candidate structure modification to the first independent geometric copy, and only the second candidate structure modification to the second independent geometric copy. Both the first and second single-modification structures undergo complete folding simulation from the unfolded pose, using the same packaging folding sequence, indentation line target angle value, folding angle sampling step size, surface triangular patch division accuracy, and contact detection accuracy. After applying the first candidate structure modification, regenerate the folded contact anchor chain, selecting the first one containing the same two packaging structure units as the original defect anchor position. The first contact point with the smallest absolute value of the initial contact angle difference is updated. Specifically, the contact unit pairing key is formed by assigning the numbers of the two packaging structure units contained in the original defect anchor position in ascending numerical order. Candidate first contact points with the same contact unit pairing key are then selected from the newly generated first contact points. If no candidate first contact point exists, the current application sequence is terminated. If multiple candidate first contact points exist, they are sorted in ascending order by the absolute value of the initial contact angle difference, then by the Euclidean distance between the coordinates of the first contact point and the coordinates of the original defect anchor position, and finally by the initial contact point number. The first point in the sorted sequence is determined as the first contact point to be updated. If the absolute value of the initial contact angle difference of the updated first contact point is greater than the updated contact angle tolerance value, the current application sequence is terminated. The application order and the updated contact angle tolerance value can be taken as half to one folding angle sampling step, with the specific value determined based on the folding angle sampling step and the linear interpolation error of the first contact angle value. The corresponding contour edge of the second candidate structure modification action contour edge after the first candidate structure modification is determined as the updated contour edge. In specific implementation, the starting endpoint identity code and ending endpoint identity code of the second candidate structure modification action contour edge are mapped to the same packaging structure unit after the first candidate structure modification is applied, and the continuous boundary between the two endpoint identity codes is determined as the updated contour edge. If no updated contour edge is found, the current application order is terminated. If multiple continuous boundaries are found, the first continuous boundary is selected in ascending order of continuous boundary number.From the two surface points of the initial contact point, select the surface point located on the surface of the packaging structural unit that is the target of the second candidate structural modification. Project the corresponding surface point along the surface normal of the packaging structural unit onto the updated contour edge. Divide the cumulative arc length from the starting endpoint of the updated contour edge to the projection point by the total arc length of the updated contour edge to obtain the arc length ratio. When the projection point is outside the range of the updated contour edge, determine the endpoint of the updated contour edge closest to the projection point as the projection position. Determine the update action point of the second candidate structural modification on the updated contour edge according to the arc length ratio. Based on the angle and lateral relationship between the modification direction of the second candidate structural modification and the outward normal of the original action contour edge, generate the corresponding update contour edge. Update the modification direction vector; move the boundary corresponding to the update action point along the update modification direction vector according to the parameter change in the second candidate structure modification record, update the affected boundary and perform a geometric integrity check. After the check passes, write the first candidate structure modification and the repositioned second candidate structure modification together into the positive double modification structure; perform the same operation in reverse order, first apply the second candidate structure modification, then map the first candidate structure modification corresponding to the update first contact point, update the contour edge, update the action point and update the modification direction vector, apply the first candidate structure modification according to the parameter change in the first candidate structure modification record, and generate the reverse double modification structure; the current application order may have un-updated parts. The corresponding application sequence is terminated if any of the following occurs: initial contact point, failure to obtain updated contour edges, or failure to pass the geometric integrity check; the forward double modification structure and the reverse double modification structure are respectively associated with the candidate modification pair number, execution order code value, and corresponding geometric state data; the original arc length ratio values ​​of the original defect anchors on the corresponding contour edges of the two packaging structure units are read; in specific implementation, the two surface points corresponding to the initial contact point of the original defect anchors are projected onto the corresponding contour edges of the two packaging structure units respectively, and the first and second original arc length ratio values ​​are generated by dividing the cumulative arc length value from the starting endpoint of the corresponding contour edge to the projection point by the total arc length value of the corresponding contour edge; in the forward double modification structure and the reverse double modification structure... In the double-modification structure, two material points are determined according to the identity codes of the starting and ending endpoints of the corresponding contour edges and the corresponding original arc length ratios. When the corresponding contour edges are re-divided into triangular patches, the centroid coordinates of the material points are calculated in the updated triangular patches containing the material points, and the coordinates of the material points and the surface normal vectors are determined according to the vertex coordinates of the updated triangular patches. In the independent folding simulation replicas of the positive and negative double-modification structures, the midpoints of the two material points are constrained to coincide with the original defect anchors, and the included angle of the normals of the surfaces where the two material points are located is constrained to be consistent with the included angle of the normals when the reference packaging structure first contacts, thus obtaining the positive anchor locking state and the negative anchor locking state.In practice, the baseline packaging structure, forward double-modification structure, reverse double-modification structure, forward locking simulation copy, and reverse locking simulation copy all adopt the packaging die coordinate system. The origin and the X, Y, and Z axes of the packaging die coordinate system remain unchanged. The unfolded coordinate values ​​of each packaging structure unit are converted into spatial coordinate values ​​through the rigid body transformation matrix of the corresponding folding stage. The original defect anchor coordinate values ​​and the normal vectors of the surfaces where the two material points are located at the first contact are read from the baseline packaging structure, and the baseline normal angle between the two normal vectors is calculated. The packaging structure unit that is directly connected to the current indentation line and remains stationary in the current folding stage is determined as the reference packaging structure unit. The unit containing two material points and capable of connecting along the folding joint is defined as the reference packaging structure unit. The packaging structure unit in motion is determined to be an adjustable packaging structure unit; the spatial pose of the reference packaging structure unit remains unchanged. The translation increments and rotation increments around the X, Y, and Z axes of each adjustable packaging structure unit along the packaging die coordinate system are used as constraint variables. The connection relationship between adjacent packaging structure units is maintained through the coincidence constraint of the indentation line endpoints and the constraint of the folding connection axis. The parameter changes of the candidate structure modification remain unchanged. The three-dimensional coordinate difference vector between the midpoint coordinates of two material points and the original defect anchor coordinates is determined as the position constraint residual. The difference between the included angle of the surface normals of the two material points and the included angle of the reference normal is determined as the attitude constraint residual. The coordinate difference between the endpoints of the indentation line of the unit is determined as the connection constraint residual. An augmented Lagrangian constraint solution method is used, iteratively updating the translation and rotation increments of each adjustable packaging structure unit based on the position constraint residual, attitude constraint residual, and connection constraint residual. In each iteration, the material point coordinates and surface normal vector are updated, and the three constraint residuals are recalculated. The constraint solution is considered convergent when the magnitude of the position constraint residual is not greater than the anchor locking position tolerance, the absolute value of the attitude constraint residual is not greater than the anchor locking angle tolerance, and the magnitude of the connection constraint residual is not greater than the indentation line connection tolerance. The anchor locking position tolerance can be taken from 0.05mm to 0.20mm, with the specific value determined based on the packaging die coordinate resolution and the average side length of the triangular facet. The minimum adjustment amount for the value and die-cutting position is determined. The tolerance value for the anchor locking angle can be 0.1° to 0.5°, with the specific value determined based on the sampling step size of the folding angle and the calculation error of the surface normal. The tolerance value for the indentation line connection can be 0.02mm to 0.10mm, with the specific value determined based on the coordinate accuracy of the reference packaging die drawing and the average side length of the triangular facet. The maximum number of iterations can be 50 to 200. If the three convergence conditions are not met even after reaching the maximum number of iterations, the corresponding anchor locking state is not generated, and the corresponding execution order is determined as anchor locking failure. When the three convergence conditions are met, a positive anchor locking state and a negative anchor locking state are generated respectively, and the candidate modification pair number, execution order code value, and convergence result are associated.

[0030] In this implementation scheme, by comparing the same candidate modification pair in pairs under positive double modification structure, reverse double modification structure and corresponding anchor locking state, and by using the arc length ratio value to maintain the material consistency of the candidate structure modification action position, the geometric deviation caused by the migration of the first contact point can be separated from the influence of the application order of the two candidate structure modifications. This allows for a consistent evaluation of the sequential coupling relationship, anchor retention capability and defect improvement stability of the candidate modification pair, reducing misjudgments caused by absolute coordinate drift, material point mismatch and contact posture changes. This provides a verifiable and sequentially comparable structural state basis for subsequent retention of structure modification screening, contact burden transfer judgment and candidate contact closure sequence construction.

[0031] Specifically, the steps for selecting and retaining structural modifications are as follows: Read the corresponding original defect anchor position, first candidate structural modification, second candidate structural modification, first single modification structure, second single modification structure, forward double modification structure, reverse double modification structure, forward anchor position locking status, and reverse anchor position locking status according to the candidate modification pair number; if the first single modification structure or the second single modification structure is not formed, or fails the cutting line intersection check, packaging structure unit contour connectivity check, and indentation line and window area intersection check, the corresponding single candidate structural modification write judgment is not executed; if the forward double modification structure is not formed, fails the geometric check, or the forward anchor position locking status does not meet the convergence condition, the forward execution order write judgment is not executed; reverse double modification structure... If the reverse anchor locking state fails to form, fails to pass geometric checks, or does not meet the convergence conditions, the write judgment for the reverse execution order is not executed. Independent folding simulation copies are established for each structural state, using the same packaging folding order, indentation line target angle value, folding angle sampling step size, packaging material parameters, surface triangular patch division accuracy, and contact detection accuracy, executing from the unfolded pose to the folding stage corresponding to the original defect anchor. The normalized value of the original defect is calculated for the first single-modification structure, the second single-modification structure, the forward double-modification structure, the reverse double-modification structure, the forward anchor locking state, and the reverse anchor locking state. The normalized value of the original defect refers to the defect type recorded for the original defect anchor corresponding to the candidate modification pair. The normalized values ​​of the same type of defects recalculated under each structural state are not the original values ​​saved in the baseline packaging structure, nor are they the aggregated results of the normalized values ​​of the four types of defects. When the defect type of the original defect anchor is insufficient tongue overlap, insufficient lock bottom overlap, insufficient adhesive bonding, and excessive contact intrusion, the normalized values ​​of tongue overlap defect, lock bottom overlap defect, adhesive bonding defect, and contact intrusion defect are calculated respectively under the corresponding structural state. The first single modification structure, the second single modification structure, the forward double modification structure, and the reverse double modification structure determine the corresponding updated first contact point according to the contact unit pairing key, the absolute value of the first contact angle difference, the Euclidean distance value of the first contact point, and the first contact point number, and are updated in the corresponding first contact point. At the contact point, the normalized value of the same type of defect is calculated; the forward anchor locking state and the reverse anchor locking state are mapped to two material points according to the first original arc length ratio value and the second original arc length ratio value, and the normalized value of the same type of defect is calculated when the midpoint of the two material points coincides with the original defect anchor point and the included angle of the surface normal of the two material points is consistent with the included angle of the reference normal; when the single modified structure does not obtain the corresponding updated first contact point, it is determined that the corresponding single candidate structure modification does not meet the writing condition; when the mapping of the corresponding material point of the forward double modified structure fails or the forward anchor locking fails, it is determined that the forward execution order does not meet the writing condition; when the mapping of the corresponding material point of the reverse double modified structure fails or the reverse anchor locking fails, it is determined that the reverse execution order does not meet the writing condition.The original defect normalized value is retained to six decimal places. When the absolute value is not greater than the normalized calculation tolerance value, it is corrected to zero. The normalized calculation tolerance value can be taken as follows: to The specific values ​​are determined based on the coordinate accuracy of the reference packaging die drawing, the average side length of the triangular facets, and the interpolation error of the first contact angle. When the normalized value of the original defect of the first single modification structure is not greater than zero, the first candidate structure modification is written into the reserved structure modification set. When the normalized value of the original defect of the second single modification structure is not greater than zero, the second candidate structure modification is written into the reserved structure modification set. When the normalized values ​​of the original defects of both the first and second single modification structures are greater than zero, and the normalized values ​​of the original defects of the forward double modification structure and the forward anchor locking state are not greater than zero, the candidate modification pair and the forward execution order are written into the reserved structure modification set. When the normalized values ​​of the original defects of both the first and second single modification structures are greater than zero, and the normalized values ​​of the original defects of the reverse double modification structure and the reverse anchor locking state are not greater than zero, the candidate modification pair and the reverse execution order are written into the reserved structure modification set. When both the forward and reverse execution orders of the same candidate modification pair meet the writing conditions, two records are retained respectively, and they are distinguished by the execution order code value. When the same candidate structural modification participates in multiple candidate modification pairs and repeatedly meets the write conditions, deduplication is performed according to the original defect anchor number and the candidate structural modification number. The retained structural modification indicates that it has passed the phased screening results of the same type of defect closure verification and the anchor locking verification of the candidate modification pair for the corresponding original defect anchor position. Subsequently, for the retained structural modification, a complete folded contact anchor chain is regenerated, the normalized values ​​of the four types of defects at each first contact point are recalculated, and the contact burden transfer modification is eliminated in combination with the changes in contact normal force and contact intrusion depth. After the screening of all candidate modification pairs is completed, the retained structural modification set is sorted in ascending order according to the arrangement position in the original defect anchor position sequence. Within the same original defect anchor position, the individual candidate structural modification is arranged before the candidate modification pair. The individual candidate structural modification is arranged in ascending order according to the candidate structural modification number, and the candidate modification pair is arranged in ascending order according to the candidate modification pair number. The individual candidate structural modification is recorded according to one execution step, and the candidate modification pair is recorded according to two consecutive execution steps. The arrangement order of the two consecutive execution steps is consistent with the execution order code value.

[0032] In this implementation scheme, by jointly comparing the original defect normalization values ​​of the first single-modification structure, the second single-modification structure, the forward double-modification structure, the reverse double-modification structure, the forward anchor locking state, and the reverse anchor locking state under consistent folding simulation conditions, it is possible to distinguish between defect closure achieved independently by a single candidate structure modification, defect closure achieved by a candidate modification pair depending on the execution order, and surface closure results caused by the migration of the first contact point. This ensures that the single candidate structure modifications, candidate modification pairs, and execution order written into the retained structure modification set all have clear defect elimination and anchor maintenance bases. Furthermore, by repeatedly recording deduplication and organizing execution steps, the consistency of the subsequent application process is maintained, thereby improving the stability, verifiability, and actual execution reliability of the retained structure modification screening results, and providing reliable input for contact burden transfer judgment and candidate contact closure sequence generation.

[0033] Specifically, the steps for generating a first-level rectification candidate sequence are as follows: Based on the changes in contact normal force and contact intrusion depth, contact burden transfer modifications are eliminated from the retained structure modifications. Candidate contact closure sequences are formed based on the remaining retained structure modifications and then revoked item by item. For each individual modification and candidate modification pair in the retained structure modification set, the baseline packaging structure and corresponding folding simulation data are copied. For each individual modification, only the corresponding candidate structure modification is applied. For each candidate modification pair, two candidate structure modifications are applied sequentially according to the execution order encoding values, and the step-by-step folding is re-executed from the unfolded pose. The baseline packaging structure and the modified packaging structure use the same thin-shell finite element model, packaging folding order, indentation line target angle value, and folding angle sampling step size. The surface triangular facet division method, contact stiffness parameters, surface friction coefficient, and contact convergence error are considered. The thin-shell finite element model is established based on the elastic modulus, Poisson's ratio, bending stiffness, and cardboard thickness parameters of the packaging material. Packaging structural units not involved in the current folding action are maintained in their current spatial pose. Active packaging structural units are subjected to angular boundary conditions around the corresponding indentation lines, and the folding connection between adjacent packaging structural units is maintained through the coincidence of the indentation line endpoints. A penalty function contact calculation method is used to detect the contact state of the packaging structural unit surface. The contact stiffness parameters are determined based on the elastic modulus, cardboard thickness, and average triangular facet area of ​​the contact region. For each initial contact point in the baseline packaging structure, [the following parameters are considered]. The angle value obtained by adding a folding angle sampling step to the initial contact angle value is determined as the corresponding contact evaluation angle value. When the added angle value is greater than the target rotation angle value of the corresponding indentation line, the target rotation angle value of the corresponding indentation line is determined as the corresponding contact evaluation angle value. Contact data is extracted for the corresponding initial contact points before and after modification under the same folding stage and the same contact evaluation angle value. The reaction force components of each contact node in the contact area along the normal direction of the initial contact point are accumulated to obtain the contact normal force value in N. The maximum value of the penetration depth values ​​of each contact node returned by the penalty function contact calculation is determined as the contact intrusion depth value in mm. The contact normal force value before modification of the original defect anchor position is subtracted from the modified contact normal force value to obtain the contact normal force value. Normal force reduction value; according to the original defect anchor number, read the corresponding packaging structure unit number, folding stage number, first contact angle value and two original arc length ratio values. In the modified folded contact anchor chain, select the updated first contact point with the same contact unit pairing key and folding stage number. Then, select the first updated first contact point in ascending order of the absolute value of the first contact angle difference, the sum of the differences of the two arc length ratio values, and the updated first contact point number. This first updated first contact point is determined as the corresponding first contact point after modification. If no corresponding first contact point after modification is found, the modified contact normal force value and contact intrusion depth value are recorded as zero. If the contact normal force reduction value is not greater than zero, the contact burden transfer deletion judgment for the corresponding retained structure modification is not performed.The first contact point located after the original defect anchor and containing any packaging structure unit number of the original defect anchor is extracted from the folded contact anchor chain of the reference packaging structure to form a set of subsequent first contact points. These are then paired in the modified folded contact anchor chain according to the contact unit pairing key, folding stage number, absolute value of the first contact angle difference, and first contact point number. For successfully paired subsequent first contact points, the increase in contact normal force is obtained by subtracting the original contact normal force value from the modified contact normal force value, and the increase in contact penetration depth is obtained by subtracting the original contact penetration depth value from the modified contact penetration depth value. For subsequent first contact points that existed before modification but did not form a pair after modification, the modified contact normal force value is... The contact penetration depth value is recorded as zero. For subsequent first contact points added after modification but not paired before modification, the contact normal force value and contact penetration depth value before modification are recorded as zero. The smaller value between the newly added first contact angle value after adding a folding angle sampling step and the corresponding indentation line target angle value is determined as the contact evaluation angle value. The absolute value of the increase in contact normal force is corrected to zero when it is not greater than the contact normal force numerical comparison tolerance value. The absolute value of the increase in contact penetration depth is corrected to zero when it is not greater than the contact penetration depth numerical comparison tolerance value. The contact normal force numerical comparison tolerance value can be taken from 0.1N to 1N, and the specific value is determined based on the contact solution residual and force value verification error. The contact penetration depth numerical comparison tolerance value is... The value can be taken from 0.01mm to 0.05mm, and the specific value is determined based on the coordinate accuracy of the reference packaging die drawing and the average side length of the surface triangular facets. When the decrease in contact normal force is greater than zero, the sum of all positive increases in contact normal force is not less than the decrease in contact normal force, and any increase in contact penetration depth is greater than zero, the corresponding single modification or candidate modification pair is identified as a contact burden transfer modification and deleted. Among them, the sum of all positive increases in contact normal force only accumulates the increases in contact normal force that are greater than zero. According to the original defect anchor position sequence, each original defect anchor position is processed from front to back. For all the single modifications and candidate modification pairs that have not been deleted corresponding to the current original defect anchor position, they are sorted according to the order in the retained structural modification set. Independent sub-paths are established sequentially, with a single modification applied as one execution step. Candidate modifications are applied as two consecutive execution steps based on their encoded values ​​in the execution order. After each sub-path is modified, the complete folded contact anchor chain is regenerated, and the normalized values ​​of the four types of defects corresponding to all first contact points are recalculated. All first contact points include the first contact point corresponding to the original defect anchor and the newly generated first contact point after the modification is applied. If the normalized value of the same type of defect of the current original defect anchor is not greater than zero, and no new defect anchor with a folding stage number not greater than the folding stage number of the current original defect anchor is generated, the corresponding sub-path is retained and the next original defect anchor is processed; otherwise, the corresponding sub-path is deleted.If there is no eligible retained structure modification for the current original defect anchor position and the current original defect anchor position is not the first position in the original defect anchor position sequence, backtrack to the previous original defect anchor position and continue expanding from the next unenumerated retained structure modification. If there is no unenumerated retained structure modification for the previous original defect anchor position, continue backtracking forward. If the current original defect anchor position is the first position in the original defect anchor position sequence and there is no eligible retained structure modification, terminate the current search path. The same retained structure modification in the same search path is applied only once. For sub-paths that repeatedly form the same sequence of boundary point coordinate values, only the sub-path with the earlier order is retained. After all original defect anchor positions are processed, the complete folded contact anchor chain is regenerated and the normalized values ​​of the four types of defects corresponding to all first contact points are calculated. When all defect normalized values ​​are not greater than zero, the corresponding execution step sequence is determined as a candidate contact closure sequence. All finite branches are completed. If no candidate contact closure sequence is formed during enumeration, the generation process of the first-level rectification candidate sequence is terminated, and no first-level rectification candidate sequence is output. Individual modifications and candidate modification pairs in the candidate contact closure sequence are revoked sequentially from back to front according to the execution order. Candidate modification pairs are revoked all at once as indivisible continuous execution units. After each revocation, the complete folding simulation is re-executed to generate the revoked folded contact anchor chain. The normalized values ​​of the four types of defects corresponding to all first contact points are recalculated, and the contact burden transfer judgment is re-executed for each retained structural modification after revocation. If there is a defect normalized value greater than zero after revocation, or if any retained structural modification again meets the deletion condition for contact burden transfer modification, the revoked individual modification or candidate modification pair is restored to its original execution position; otherwise, the corresponding individual modification or candidate modification pair is permanently deleted. After all revocations are completed, the first-level rectification candidate sequence is generated according to the original order of the retained execution steps.

[0034] In this implementation scheme, the local load reduction results of the original defect anchor position are jointly verified with the changes in contact normal force and contact intrusion depth at the subsequent first contact point of the folded contact anchor chain. The candidate contact closure sequence is then subjected to reverse cancellation verification. This ensures that the first-level rectification candidate sequence retains only the necessary single-item modifications and candidate modification pairs that maintain the normalized values ​​of all defects at no greater than zero and do not cause contact burden transfer. This avoids the formation of new stress concentration and intrusion risks at subsequent folding positions after the elimination of local defects, reduces redundant structural modifications, and improves the geometric integrity, stress coordination, execution simplicity, and verification reliability of the first-level rectification candidate sequence. This provides a clear and stable structural foundation for the generation of subsequent second-level performance improvement candidate sequences and the selection of hierarchical optimization schemes.

[0035] In this embodiment, the optimization task of the cardboard packaging structure of an electronic sensor is taken as an example. The product dimensions of the electronic sensor are 180mm×120mm×75mm, and the product weight is 0.85kg. The baseline packaging die-cutting pattern corresponds to an E-flute corrugated cardboard folding box. The baseline packaging die-cutting pattern, packaging material parameters, packaging folding sequence, target corner value of the creasing line, folding angle sampling step, minimum adjustment of the die-cutting position, and allowable parameters of the packaging structure are obtained. The folding angle sampling step is 5°, the lower limit of the tongue overlap length is 8mm, the lower limit of the bottom overlap area is 320mm², the lower limit of the adhesive bonding width is 12mm, and the upper limit of the contact penetration depth is 0.20mm. The active packaging structure units are simulated to fold step by step according to the packaging folding sequence, generating four original defect anchor positions: A1, A2, A3, and A4. For A1, a boundary modification M1 is generated for the free end of the tongue. For A2, a candidate modification pair P23 consisting of two candidate structural modifications is generated. The two candidate structural modifications in the candidate modification pair P23 are applied in reverse order, forming a forward execution order P23+ and a reverse execution order P23-, respectively. For A3, a first adhesive modification M4a and a second adhesive modification M4b are generated. For A4, an intrusion edge back-cutting modification P56 is generated. The defect normalization values ​​of the forward double modification structure and the forward anchor locking state formed by the candidate modification pair P23 according to the forward execution order P23+ are not greater than zero, and the candidate modification pair P23 and the forward execution order P23+ pass the screening. The defect normalization value of the reverse anchor locking state formed by the candidate modification pair P23 according to the reverse execution order P23- is greater than zero, and the reverse execution order P23- fails the screening. The first adhesive modification M4a increases the contact normal force value and contact intrusion depth value at the first contact point corresponding to A4, satisfying the deletion condition of the contact burden transfer modification. The second adhesive modification M4b does not produce contact burden transfer. Therefore, M1, candidate modification pair P23, and forward execution order P23+, M4b, and P56 are written into the retained structure modification set, but not into the reverse execution order P23-. M4a that meets the contact burden transfer modification deletion condition is deleted. A hierarchical optimization scheme is generated based on the retained structure modification set and the packaging structure template. After verification by folding contact anchor chain, an editable optimized packaging die drawing is output.

[0036] like Figure 2As shown, A1, A2, A3, and A4 are connected in the order of folding stages to form a folded contact anchor chain. A1 to A4 correspond to insufficient tongue overlap, insufficient bottom overlap, insufficient adhesive bonding, and excessive contact intrusion, respectively. M1 represents the tongue modification corresponding to A1, P23 represents the candidate modification pair corresponding to A2, P23+ and P23- represent the forward execution order and reverse execution order formed by applying two candidate structural modifications in the candidate modification pair P23 in reverse order, respectively, M4a and M4b represent the first adhesive modification and the second adhesive modification corresponding to A3, respectively, and P56 represents the intrusion edge back-cutting modification corresponding to A4. The candidate modification pair P23 and the forward execution order P23+ are written into the reserved structural modification set after being locked in the forward anchor position. The reverse execution order P23- is not written into the reserved structural modification set because the reverse anchor position locking fails. M4a is deleted because it meets the deletion condition of the contact burden transfer modification. M1, M4b, and P56 do not generate contact burden transfer and are written into the reserved structural modification set. Figure 2 Solid lines in the diagram represent retained paths, while dashed lines represent paths where anchor locking failed or where the conditions for modification / deletion of contact burden transfer were met.

[0037] Specifically, the steps for generating secondary performance improvement candidate sequences and tertiary replacement candidate sequences based on the remaining retained structure modifications and packaging structure templates are as follows: For each primary rectification candidate sequence, read the individual modification number, candidate modification pair number, execution order code value, and corresponding die state according to the primary rectification candidate sequence number. Identify the individual modifications and candidate modification pairs in the retained structure modification set that are not written into the current primary rectification candidate sequence as remaining retained structure modifications. For each remaining retained structure modification, copy the die state corresponding to the primary rectification candidate sequence, and add only one remaining retained structure modification to each independent die copy. The candidate modification pair is added as an indivisible continuous execution unit. The order of application and execution of structural modifications is consistent with the coded values. All folding stages are re-executed from the unfolded pose, using the same packaging folding sequence, indentation line target angle value, folding angle sampling step size, packaging material parameters, surface triangular patch division accuracy, contact stiffness parameters, and contact convergence error as the source primary rectification candidate sequence. The folding contact anchor chain is regenerated, and the normalized values ​​of the four types of defects corresponding to all first contact points are calculated. Target margin values ​​include structural safety margin, remaining material cost, remaining production time, and operational margin. The structural safety margin is the difference between the allowable structural stress value and the maximum actual stress value divided by the allowable structural stress value. The remaining material cost is the difference between the upper limit of material cost and the actual material cost. The difference in material cost is divided by the upper limit of material cost. The remaining production time is the difference between the upper limit of production time and the actual production time, divided by the upper limit of production time. The operating margin is the minimum of the normalized margin values ​​corresponding to the tongue insertion force, packaging opening operating force, bottom locking closing operating force, and product removal clearance value. Specifically, the normalized margin for the three operating forces is the difference between the upper limit of the corresponding operating force and the actual operating force, divided by the upper limit of the corresponding operating force. The normalized margin for the product removal clearance value is the difference between the product removal clearance value and the lower limit of the product removal clearance value, divided by the lower limit of the product removal clearance value. All denominators are greater than zero. Using the same data source, calculation model, and numerical precision, independent die-cutting molds are calculated separately. The four target margin values ​​of the candidate sequence for primary rectification are compared with those of the original and the source, and the four target margin values ​​of the candidate sequence for primary rectification are determined as the comparison benchmark. The independent die copy is re-verified according to the judgment steps of contact burden transfer modification. When all defect normalized values ​​are not greater than zero, no contact burden transfer occurs, at least one target margin value increases more than the margin comparison tolerance value relative to the comparison benchmark, and the changes of other target margin values ​​relative to the comparison benchmark are not less than the negative value of the margin comparison tolerance value, a secondary performance improvement candidate sequence is generated. The margin comparison tolerance value can be taken from 0.001 to 0.01, and the specific value is determined based on the calculation accuracy of the target margin value, the measurement error of the packaging material parameters, and the statistical error of the processing time.When different remaining structures are modified into the same primary rectification candidate sequence, secondary performance improvement candidate sequences are generated separately. When different addition paths result in the same die geometry, a geometric summary value is generated based on the coordinate sequence of the packaging structure unit contour points, the coordinate sequence of the indentation line endpoints, and the coordinate sequence of the bonding area boundary points. If the geometric summary values ​​are the same, the secondary performance improvement candidate sequence with the larger minimum target margin value is retained. If the minimum values ​​are the same, the secondary performance improvement candidate sequence with the larger sum of the four target margin values ​​is retained. If there is no primary rectification candidate sequence with all four target margin values ​​not less than zero, parametric die drawings with product dimensions and weight values ​​within the applicable range are selected from the packaging structure template. The template table reads the template number, applicable product length range, applicable product width range, applicable product height range, applicable product weight range, packaging structure unit connection relationship, packaging material code value, parameterized position, and parameter adjustment range. Each applicable range includes a lower limit and an upper limit, with the upper limit of each applicable range being greater than the corresponding lower limit. Based on similar packaging structure templates that have completed physical trial assembly, load-bearing tests, and folding verification, these values ​​are pre-written into the packaging structure template table. When the product length, width, height, and weight values ​​are not less than the corresponding lower limit and not greater than the corresponding upper limit, the corresponding parameterized die-cutting pattern is determined as a candidate parameterized die-cutting pattern. The endpoints of the range are included in the applicable range. When multiple candidate parametric die-cutting patterns exist, the absolute differences between the product length, product width, product height, and product weight values ​​and the corresponding center values ​​of the applicable range are calculated separately, and then divided by the difference between the upper limit and lower limit of the applicable range to obtain four normalized deviation values. The candidate parametric die-cutting patterns are arranged in ascending order according to the sum of the four normalized deviation values, and template replacement paths are generated according to the arrangement order. The parametric die-cutting pattern records the local coordinate system of each packaging structure unit, the connection relationship of the packaging structure unit, the parent contour edge number corresponding to the indentation line, the relative position parameters of the tongue root, the relative position parameters of the slot center, the adhesive edge width parameters, the relative position parameters of the free end of the locking bottom piece, and the allowable parameters for each parameter. Adjust the range; when generating the template alternative path, first adjust the internal length value of the packaging to the sum of the product length value and the lower limit of the clearance on both sides, adjust the internal width value of the packaging to the sum of the product width value and the lower limit of the clearance on both sides, and adjust the internal height value of the packaging to the sum of the product height value, the lower limit of the top clearance, and the lower limit of the bottom clearance. The lower limit of the clearance can be 1mm to 10mm, and the specific value is determined according to the product surface protection requirements, the thickness of the cushioning material, the product loading direction, and the product unloading path; then, according to the adjusted internal dimensions of the packaging, reposition the embossing line that forms the main body of the packaging, and translate the packaging structural units connected to the embossing line synchronously according to the local coordinate system, keeping the connection relationship of the packaging structural units and the connection relationship of the endpoints of the embossing line unchanged;Subsequently, the structural positions are updated sequentially according to the parent boundary numbers of the tongue, slot, adhesive edge, and locking bottom piece. The root of the tongue moves synchronously with the corresponding crease line, and the free end boundary of the tongue is adjusted along the insertion direction until the effective overlap length of the tongue is not less than the lower limit of the overlap length. The center of the slot is determined according to the projection position of the tongue centerline on the receiving packaging structural unit. The slot opening width is determined according to the sum of the tongue thickness and the insertion gap. The insertion gap can be 0.2mm to 1.0mm, and the specific value is determined based on the cardboard thickness tolerance and die-cutting position error. The inner boundary of the adhesive edge remains unchanged in its connection position with the corresponding crease line, and the outer boundary of the adhesive edge is adjusted along the width direction until the effective bonding width of the adhesive area is not less than the lower limit of the bonding width. The root boundary of the locking bottom piece remains aligned with the corresponding crease line, and the free end boundary of the locking bottom piece is adjusted along the overlap direction until the effective overlap area of ​​the locking bottom piece is not less than the lower limit of the overlap area. Limits; the changes at each position are limited to the allowable adjustment range of the parameters, and are updated according to integer multiples of the minimum adjustment amount of the die-cutting position; after the parameter linkage update is completed, the following checks are performed: cutting line intersection check, packaging structure unit contour connectivity check, crease line and window area intersection check, cardboard unfolding boundary check, crease line endpoint connection check, and parameter allowable adjustment range check. If any check fails, the corresponding template replacement path is deleted and the next candidate parameterized die drawing is read; for parameterized die drawings that pass all checks, a complete step-by-step fold is performed from the unfolded pose, the folding contact anchor chain is regenerated, and the normalized values ​​of the four types of defects corresponding to all first contact points are calculated. When all defect normalized values ​​are not greater than zero, a third-level replacement candidate sequence is generated; when all candidate parameterized die drawings fail the geometric check and defect normalized value check, the third-level replacement candidate sequence generation process is terminated, and no third-level replacement candidate sequence is output.

[0038] In this implementation plan, a remaining structural modification is introduced based on the primary rectification candidate sequence. Under the joint constraints of defect normalization value, contact burden transfer, and four target margin values, a secondary performance improvement candidate sequence is generated. At the same time, when the primary rectification candidate sequence cannot meet the target margin requirements, a tertiary replacement candidate sequence is generated using the packaging structure template. This makes the packaging structure optimization form a continuous decision path from partial rectification and performance improvement to overall replacement. It avoids performance improvement at the expense of defect reproduction, contact burden transfer, and other target margin reductions. It also provides a complete replacement solution for the baseline packaging die drawing that is not suitable for further partial modification. This improves the coverage, structural adaptability, performance coordination, and reliability of subsequent optimization scheme selection of the hierarchical candidate sequence.

[0039] Specifically, the steps for calculating the target margin values ​​of each level of candidate sequences and screening the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan are as follows: According to the candidate sequence number, read the die-cutting drawings, packaging material parameters, product dimensions, product weight, packaging structure allowable parameters, and folding contact anchor chains corresponding to the first-level rectification candidate sequence, the second-level performance improvement candidate sequence, and the third-level alternative candidate sequence. Under the same packaging folding sequence, indentation line target angle value, folding angle sampling step size, surface triangular facet division accuracy, and contact calculation conditions, calculate the structural safety margin value, remaining material cost value, and remaining production time value, respectively. The margin values ​​and operational margin values; all four indicator margin values ​​are dimensionless values. Positive values ​​indicate that the corresponding technical indicator has a surplus, zero indicates that the corresponding technical indicator has reached the allowable boundary, and negative values ​​indicate that the corresponding technical indicator has exceeded the allowable boundary. When calculating the structural safety margin value, the product of the product weight value and the gravitational acceleration value is allocated to the corresponding packaging structural unit according to the contact area ratio between the product and the packaging structural unit. The contact normal force value extracted from the folding contact anchor chain is applied to the corresponding contact area. Based on the elastic modulus value, Poisson's ratio value, bending stiffness value, and cardboard thickness value, thin-shell finite element calculation is performed on each packaging structural unit. The maximum value among the maximum equivalent stress values ​​is determined as the maximum actual stress value; the allowable structural stress value is generated by dividing the ultimate stress value obtained from the compression test of the same material paperboard by the structural safety factor, which can be taken as 1.2 to 2.0, and the specific value is determined according to the product weight grade, the number of stacking layers during transportation, and the level of transportation vibration; the difference between the allowable structural stress value and the maximum actual stress value is divided by the allowable structural stress value to obtain the structural safety margin value, and the units of the maximum actual stress value and the allowable structural stress value are both MPa; when calculating the remaining material cost value, the actual usable area value of the paperboard is calculated based on the die-cutting diagram corresponding to the candidate sequence, and the cutting... The total length of the cutting lines, the total length of the crease lines, and the total length of the bonding path are calculated by multiplying the actual usable area of ​​the cardboard by the price per unit area, the total length of the cutting lines by the price per unit cutting length, the total length of the crease lines by the price per unit crease length, and the total length of the bonding path by the price per unit bonding length. This yields the actual material cost. Each unit price is retrieved from the material price list corresponding to the current packaging material code and the processing price list corresponding to the current production equipment. The difference between the upper limit of material cost and the actual material cost is divided by the upper limit of material cost to obtain the remaining material cost.The actual material cost and the upper limit of material cost are in the same currency unit. When calculating the remaining production time, the average processing speed, single start-stop time, and bonding curing time are read from the die-cutting equipment operation log, creasing equipment operation log, and bonding equipment operation log. The total length of the cutting lines is divided by the average feed speed of the die-cutting equipment, and then the product of the number of cutting paths and the single start-stop time is added to obtain the die-cutting time. The total length of the creasing lines is divided by the average processing speed of the creasing equipment to obtain the creasing time. The total length of the bonding paths is divided by the average processing speed of the bonding equipment, and then the bonding curing time is added to obtain the bonding time. The actual production time is then calculated by adding the die-cutting time, creasing time, and bonding time together. The upper limit of production time is then... The difference between the actual production time and the upper limit of production time is divided to obtain the remaining production time. Both the actual and upper limit production time are in seconds. When calculating the operational margin, simulations of tongue insertion, packaging opening, bottom locking, and product removal are performed at the same quasi-static operating speed. The quasi-static operating speed can range from 1 mm / s to 10 mm / s, with the specific value determined based on the packaging operation test speed and the operating force sampling frequency. The insertion direction is determined by the direction from the tongue centerline to the slot centerline. The packaging opening direction and product removal direction are read from the packaging process card. The maximum reaction force during the tongue's movement along the insertion direction is determined as the tongue insertion force value. The maximum reaction force during the movement of the product along the packaging opening direction is determined as the packaging opening operation force value; the maximum reaction force during the movement of the locking bottom plate to the closed position is determined as the locking bottom closing operation force value; the minimum distance between the product surface and the packaging structural unit during the product movement along the product removal direction is determined as the product removal clearance value; the difference between the upper limit of the tongue insertion force and the upper limit of the tongue insertion force is divided by the upper limit of the tongue insertion force to obtain the tongue operation margin value; the difference between the upper limit of the packaging opening operation force and the upper limit of the packaging opening operation force is divided by the upper limit of the packaging opening operation force to obtain the opening operation margin value; the difference between the upper limit of the locking bottom closing operation force and the upper limit of the locking bottom closing operation force is divided by the upper limit of the locking bottom closing operation force to obtain the locking bottom closing operation force value. The bottom operation margin value is obtained by dividing the difference between the product removal clearance value and the lower limit of the product removal clearance value by the lower limit of the product removal clearance value. The minimum value among the four operation margin values ​​is determined as the operating margin value. The units of the tongue insertion force value, packaging opening operation force value, and bottom locking operation force value are all in N, and the unit of the product removal clearance value is mm. The allowable structural stress value, material cost upper limit value, production time upper limit value, tongue insertion force upper limit value, packaging opening operation force upper limit value, bottom locking operation force upper limit value, and product removal clearance lower limit value must all be greater than zero. If any normalized reference value is not greater than zero, the target margin calculation of the corresponding candidate sequence is stopped and the corresponding candidate sequence is deleted.After calculating the target margin value, delete any candidate sequence with a target margin value less than zero. Within the Level 1 rectification candidate sequence, Level 2 performance improvement candidate sequence, and Level 3 replacement candidate sequence, arrange them in descending order of the minimum of the four target margin values. The first position in each ranking is then determined as the Level 1 rectification plan, Level 2 improvement plan, and Level 3 replacement plan, respectively. If multiple candidate sequences with the same minimum target margin value exist within the same level, they are arranged sequentially in descending order of the sum of the four target margin values, ascending order of the number of candidate structure modifications, and ascending order of the candidate sequence number, resulting in a unique ranking. If no candidate sequence with a target margin value greater than zero exists at any level, no optimization plan is generated for that level, and the selection of candidate sequences for other levels continues. If no candidate sequence with a target margin value greater than zero exists at any of the three levels, the hierarchical scheme selection is terminated, and no Level 1 rectification plan, Level 2 improvement plan, or Level 3 replacement plan is output.

[0040] In this implementation plan, structural safety margin, remaining material cost, remaining production time, and operational margin are uniformly converted into dimensionless evaluation results with consistent direction. The minimum target margin is used as the primary ranking criterion for each level of candidate sequence. This ensures that the first-level rectification candidate sequence, the second-level performance improvement candidate sequence, and the third-level replacement candidate sequence maintain an overall balance among safety load, material input, production efficiency, and operational considerations. This avoids situations where outstanding performance of a single objective masks weak objectives approaching the allowable boundary. Furthermore, by combining negative value deletion conditions and unique ranking rules, it ensures that the first-level rectification scheme, the second-level improvement scheme, and the third-level replacement scheme all have clear constraint satisfaction, stable priority order, and verifiable decision results. This improves the reliability of the hierarchical optimization scheme selection and its practical application adaptability.

[0041] Specifically, the steps for updating the corresponding die-cutting pattern and outputting the graded optimization scheme and editable optimized packaging die-cutting pattern after verification by folding contact anchor chains are as follows: According to the sorting results of the first-level rectification candidate sequence, the second-level performance improvement candidate sequence, and the third-level replacement candidate sequence, verification is performed sequentially starting from the first in the sorting order; for the first-level rectification candidate sequence and the second-level performance improvement candidate sequence, the baseline packaging die-cutting pattern is copied, and corresponding candidate structure modifications are applied according to the candidate structure modification number sequence. A single modification is treated as an execution step to update the action contour edge. For each candidate modification, two action contour edges are continuously updated according to the execution order code value, and the coordinate values ​​of the endpoints of the affected contour edges, the intersection points of adjacent contour edges, and the coordinate values ​​of the intersection points are recalculated. Closed path connection relationships; For the third-level alternative candidate sequence, copy the parametric die-cutting diagram corresponding to the packaging structure template number, update the parametric geometric constraints according to the internal dimensions of the packaging, the position parameters of the tongue, the slot, the adhesive edge, the locking plate, and the indentation line, and resolve the contour point coordinates of each packaging structure unit; After the die-cutting diagram is updated, perform cutting line intersection checks, packaging structure unit contour connectivity checks, indentation line and window area intersection checks, adjacent packaging structure unit common edge consistency checks, and die-cutting diagram outer boundary checks. If any check fails, terminate the current candidate sequence re-verification and read the next ranked candidate sequence at the same level; All geometric checks pass. Outdated designs are retained in the updated die-cutting pattern drawing, the original contour edge numbers are preserved, a modification version number is added to the modified boundary, and the candidate structure modification number, the sequence of modified front-end point coordinate values, the sequence of modified rear-end point coordinate values, parameter changes, and execution order encoding values ​​are recorded. The die-cutting pattern drawing corresponding to the three-level replacement candidate sequence simultaneously records the packaging structure template number and the values ​​of the template parameters before and after modification. The die-cutting geometry is saved as a DXF vector file, and the contour edge numbers, parameter changes, candidate sequence numbers, and modification version numbers are saved as a JSON associated file. The DXF vector file and the JSON associated file are linked using the same die-cutting pattern drawing number to establish a correspondence, generating an editable optimized packaging die-cutting pattern drawing. The saved DXF vector file and JSON associated file are reread for cutting lines, indentation lines, window boundary lines, adhesive area boundary lines, contour edge numbers, parameter changes, and packaging folding parameters. The packaging structural units are re-divided and the connection relationships between the packaging structural units are established. Complete step-by-step folding is performed from the unfolded pose. The verification process uses the same packaging folding sequence, indentation line target angle value, folding angle sampling step size, surface triangular patch division accuracy, contact stiffness parameters, and contact convergence error as the corresponding candidate sequence generation stage. The folding contact anchor chain is reconstructed based on the recalculated first contact angle value, first contact point, active packaging structural unit number, contacted packaging structural unit number, and contour edge number.For all reconstructed initial contact points, recalculate the normalized values ​​for tongue overlap defects, lock bottom overlap defects, adhesive bonding defects, and contact intrusion defects. Also recalculate the structural safety margin, remaining material cost, remaining production time, and operational margin. For the first-level rectification candidate sequence and the second-level performance improvement candidate sequence, complete the initial contact point pairing before and after optimization according to the contact unit pairing key, folding stage number, absolute value of the initial contact angle difference, and initial contact point number. Recalculate the reduction in contact normal force at the original defect anchor position, the sum of the positive increase in contact normal force at subsequent initial contact points, and the increase in contact intrusion depth. Perform a re-verification according to the deletion conditions for contact burden transfer modification. If no contact burden transfer occurs, all defect normalized values ​​are not greater than zero, and all four objective margin values ​​are not less than zero, the corresponding candidate sequence is determined as a first-level rectification scheme or a second-level improvement scheme, written into the hierarchical optimization scheme, and the corresponding editable optimized packaging die drawing is output. For the third-level replacement candidate sequence... When all defect normalized values ​​are not greater than zero and all four objective margin values ​​are not less than zero, the corresponding candidate sequence is determined as a level 3 alternative solution, written into the hierarchical optimization scheme, and the corresponding editable optimized packaging die drawing is output. If any re-verification condition is not met, the next ranked candidate sequence of the same level is read and the die drawing update, geometric check, folded contact anchor chain reconstruction, and re-verification are re-executed. When all level 1 rectification candidate sequences are exhausted and no level 1 rectification solution is formed, no level 1 rectification solution or corresponding optimized packaging die drawing is output, and the level 2 performance improvement candidate sequence is re-verified. When all level 2 performance improvement candidate sequences are exhausted and no level 2 improvement solution is formed, no level 2 improvement solution or corresponding optimized packaging die drawing is output, and the level 3 alternative candidate sequence is re-verified. When all level 3 alternative candidate sequences are exhausted and no level 3 alternative solution is formed, no level 3 alternative solution or corresponding optimized packaging die drawing is output. When all three levels of candidate sequences are exhausted and none pass the re-verification, the hierarchical optimization scheme output process is terminated, and no hierarchical optimization scheme or editable optimized packaging die drawing is output.

[0042] In this implementation plan, the optimized packaging die-cutting pattern corresponding to the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan are treated as independent verification objects. The regenerated folded contact anchor chain, defect normalization value, and target margin value are used as unified verification criteria. This ensures that the screening results of the hierarchical optimization plan can be truly mapped to the final die-cutting geometry, avoiding the influence of temporary geometric states, contact solution history, and parameter caching on the output results during the candidate sequence generation process. At the same time, combined with the contact burden transfer verification and the supplementary mechanism of the next-level sorting result, it is ensured that the final output hierarchical optimization plan and the editable optimized packaging die-cutting pattern are consistent in terms of boundary modification, folded contact relationship, defect closure state, and target margin constraint, thereby improving the executability, traceability, and delivery reliability of the optimization results.

[0043] like Figure 3 As shown, structural modifications are applied to the original defect anchor sequence, and candidate contact closure sequences are canceled one by one to generate a first-level rectification candidate sequence. For each first-level rectification candidate sequence, an unused structural modification is added to generate a second-level performance improvement candidate sequence. When there is no first-level rectification candidate sequence with all four target margin values ​​not less than zero, parametric die-cutting diagrams with product external dimensions and product weight values ​​within the applicable range are selected from the packaging structure template, and the internal dimensions of the packaging and the corresponding structural positions are adjusted to generate a third-level alternative candidate sequence. The structural safety margin, remaining material cost, remaining production time, and operational margin values ​​of each level of candidate sequence are calculated respectively. The candidate sequences at each level are sorted in descending order according to the minimum value among the target margin values, and the first position of each level is determined as the first-level rectification scheme, the second-level improvement scheme, and the third-level alternative scheme, respectively. The corresponding die-cutting diagrams are updated according to the optimization schemes at each level. After verification by folding the contact anchor chain, the corresponding graded optimization schemes and editable optimized packaging die-cutting diagrams are output.

[0044] like Figure 4 As shown, the second aspect of the present invention provides a packaging structure optimization system based on multi-objective decision-making, comprising: a folding anchor chain generation module, used to acquire a reference packaging die drawing, packaging folding parameters, and allowable parameters of the packaging structure; simulate the step-by-step folding of packaging structure units; determine the position where the non-directly connected packaging structure units first make surface contact as the first contact point and connect them to form a folding contact anchor chain; calculate the defect normalization value based on the first contact point and generate an original defect anchor sequence; and generate candidate structure modifications based on the original defect anchors; and a dual-order anchor solution module, used to apply two candidate structure modifications in reverse order to the same original defect anchor, generating a forward dual-modification structure, a reverse dual-modification structure, and... The system is designed to: filter and retain structural modifications corresponding to the anchor locking status; generate a closed-level generation module to eliminate contact burden transfer modifications from the retained structural modifications based on changes in contact normal force and contact intrusion depth, form candidate contact closure sequences based on the remaining retained structural modifications and cancel them one by one, generate a first-level rectification candidate sequence, and generate a second-level performance improvement candidate sequence and a third-level replacement candidate sequence based on the remaining retained structural modifications and packaging structure template; and use a graded decision write-back module to calculate the target margin values ​​of each level of candidate sequence, filter the first-level rectification scheme, the second-level improvement scheme and the third-level replacement scheme, update the corresponding die-cutting diagram, and output the graded optimization scheme and an editable optimized packaging die-cutting diagram after verification by folding the contact anchor chain.

[0045] In this implementation scheme, by connecting the folded contact anchor chain, the original defect anchor sequence, retained structural modifications, hierarchical candidate sequences, target margin values, and optimized packaging die-cutting diagrams into a continuous data processing chain, the packaging structure scheme can form a closed decision-making process from folded contact defect location, candidate structural modification screening, contact burden transfer and elimination, necessary modification retention, performance improvement, template replacement, to die-cutting diagram verification. This can identify the impact of the execution order of candidate structural modifications and anchor migration, while also taking into account structural safety margin values, remaining material cost values, remaining production time values, and operational margin values. It avoids the subsequent increase in contact burden and the decrease in other target margins caused by the improvement of local defects, and ensures that the final output hierarchical optimization scheme and the editable optimized packaging die-cutting diagram are consistent in terms of folded contact relationships, defect closure states, target margin constraints, and actual geometric boundaries, thereby improving the integrity, reliability, executability, and traceability of the packaging structure optimization results.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0047] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A packaging structure optimization method based on multi-objective decision-making, characterized in that, For folding cardboard box packaging structures, the packaging structure is composed of multiple packaging structure units enclosed by cutting lines and crease lines, including: S1. Obtain the baseline packaging die drawing, packaging folding parameters and packaging structure allowable parameters. Simulate the packaging structure unit folding step by step. Determine the first contact point as the first contact point of the non-directly connected packaging structure unit and connect them to form a folding contact anchor chain. Calculate the defect normalization value based on the first contact point and generate the original defect anchor sequence. Generate candidate structure modification based on the original defect anchor. S2, apply two candidate structural modifications to the same original defect anchor position in reverse order to generate a positive double modification structure, a reverse double modification structure and the corresponding anchor position locking status, and filter to retain the structural modifications; S3, based on the changes in contact normal force and contact intrusion depth, remove contact burden transfer modifications from the retained structure modifications, form candidate contact closure sequences based on the remaining retained structure modifications and cancel them one by one, generate a first-level rectification candidate sequence, and generate a second-level performance improvement candidate sequence and a third-level replacement candidate sequence based on the remaining retained structure modifications and packaging structure template; S4 calculates the target margin value of each candidate sequence, filters the first-level rectification plan, the second-level improvement plan and the third-level alternative plan, updates the corresponding die-cutting pattern, and outputs the graded optimization plan and editable optimized packaging die-cutting pattern after verification by folding contact anchor chain.

2. The packaging structure optimization method based on multi-objective decision-making according to claim 1, characterized in that: The specific steps for obtaining the baseline packaging die drawing, packaging folding parameters, and permissible packaging structure parameters, simulating the step-by-step folding of packaging structure units, and determining the location where non-directly connected packaging structure units first experience surface contact as the first contact point and connecting them to form a folding contact anchor chain are as follows: Obtain the baseline packaging die drawing, packaging material parameters, product dimensions, product weight, packaging folding sequence, crease line target angle value, folding angle sampling step, minimum adjustment amount of die-cutting position, and allowable parameters of packaging structure. Extract cutting lines, crease lines, window boundary lines, and adhesive area boundary lines. Divide the packaging structure into units according to the closed area enclosed by the cutting lines and determine the outline edge number of the packaging structure unit. According to the packaging folding sequence, control the active packaging structure unit to rotate around the corresponding crease line step by step. For each rotation of a folding angle, sample the step size and calculate the minimum surface distance between the active packaging structure unit and each packaging structure unit other than the packaging structure unit directly connected to the current crease line. When the current minimum surface distance value is not greater than zero and the previous minimum surface distance value is greater than zero, perform linear interpolation on the two minimum surface distance values ​​and the two folding angles to obtain the first contact angle value, and determine the midpoint of the two surface points with the smallest distance under the first contact angle as the first contact point; The first contact points are arranged according to the folding stage number and the first contact angle value; When two adjacent initial contact points have the same active packaging structure unit number, and the two initial contact points are projected onto the active packaging structure unit outline and correspond to the same outline edge number, or the corresponding outline edges have a common endpoint, the two adjacent initial contact points are connected to form a folded contact anchor chain.

3. The packaging structure optimization method based on multi-objective decision-making according to claim 2, characterized in that: The specific steps for calculating the defect normalization value based on the first contact point and generating the original defect anchor sequence, and generating candidate structure modifications based on the original defect anchors, are as follows: Calculate the effective overlap length of the tongue, the effective overlap area of ​​the locking plate, the effective bonding width of the adhesive area, and the contact intrusion depth of the non-connected packaging structure unit under the folded state corresponding to each initial contact point; subtract the effective overlap length of the tongue, the effective overlap area of ​​the locking plate, the effective bonding width of the adhesive area, and the upper limit of the intrusion depth of the non-connected packaging structure unit from the lower limit of the overlap length, and then divide them by the corresponding allowable parameters to obtain the normalized values ​​for the four types of defects. Each positive defect normalization value, the corresponding first contact point, and the defect type are determined as an original defect anchor position, and an original defect anchor position sequence is generated according to the ascending order of the folding stage number and the descending order of the defect normalization value. For each original defect anchor position, candidate structure modifications are generated based on the defect type and contour edge number corresponding to the original defect anchor position. When the defect type is insufficient tongue overlap, the free end boundary of the tongue is moved along the insertion direction. When the defect type is insufficient lock bottom overlap, the free end boundary of the folded lock bottom piece is moved along the overlap direction. When the defect type is insufficient adhesive bonding, the outer boundary of the adhesive area is moved along the width direction. When the defect type is excessive contact intrusion, the free end boundary of the intrusion is moved in the opposite direction of the normal of the first contact point. Candidate structure modifications are generated with the minimum adjustment amount of the die-cutting position as the step size, and candidate structure modifications that cause cutting line intersection, packaging structure unit contour breakage, and indentation line entering the window area are deleted.

4. The packaging structure optimization method based on multi-objective decision-making according to claim 3, characterized in that: The specific steps for applying two candidate structural modifications to the same original defect anchor position in reverse order to generate a positive double-modification structure, a reverse double-modification structure, and the corresponding anchor position locking state are as follows: When two candidate structural modifications correspond to the same original defect anchor position, and the two candidate structural modifications are applied to the packaging structure units on both sides of the original defect anchor position or different boundaries of the same packaging structure unit, the two candidate structural modifications are combined into a candidate modification pair; the two candidate structural modifications are respectively recorded as the first candidate structural modification and the second candidate structural modification, and are applied separately to the same reference packaging structure to generate the first single modification structure and the second single modification structure. After applying the first candidate structure modification, the folded contact anchor chain is regenerated. The updated first contact point is selected that contains the same two packaging structure units as the original defect anchor position and has the smallest absolute value of the first contact angle difference. The corresponding contour edge of the second candidate structure modification action contour edge after the first candidate structure modification is determined as the updated contour edge. The arc length ratio value of the updated first contact point on the updated contour edge is calculated. The action point of the second candidate structure modification is moved to a position with the same arc length ratio value in the updated contour edge. The angle between the modification direction of the second candidate structure modification and the outward normal of the updated contour edge remains unchanged. The second candidate structure modification is applied according to the parameter change of the second candidate structure modification to generate a positive double modification structure. Perform the same operations in reverse order to generate a reversed double-modification structure; Read the original arc length ratio values ​​of the original defect anchor positions on the corresponding contour edges of the two packaging structure units; Two material points with the same original arc length ratio are selected in the positive double modification structure and the negative double modification structure, respectively. In the independent folding simulation copy, the midpoint of the two material points is constrained to coincide with the original defect anchor position, and the normal angle of the surfaces where the two material points are located is constrained to be equal to the normal angle when the reference packaging structure first contacts, so as to obtain the positive anchor position locking state and the negative anchor position locking state.

5. The packaging structure optimization method based on multi-objective decision-making according to claim 4, characterized in that: The specific steps for modifying the filter retention structure are as follows: Calculate the normalized value of the original defects for the first single-modification structure, the second single-modification structure, the forward double-modification structure, the reverse double-modification structure, the forward anchor lock state, and the reverse anchor lock state. When the normalized value of the original defects of the first single-modification structure is not greater than zero, write the first candidate structure modification into the reserved structure modification set. When the normalized value of the original defects of the second single-modification structure is not greater than zero, write the second candidate structure modification into the reserved structure modification set. When the normalized values ​​of the original defects of both the first and second single-modification structures are greater than zero, and the normalized values ​​of the original defects of the forward double-modification structure and the forward anchor lock state are not greater than zero, write the candidate modification pair and the forward execution order into the reserved structure modification set. When the normalized values ​​of the original defects of both the first and second single-modification structures are greater than zero, and the normalized values ​​of the original defects of the reverse double-modification structure and the reverse anchor lock state are not greater than zero, write the candidate modification pair and the reverse execution order into the reserved structure modification set.

6. The packaging structure optimization method based on multi-objective decision-making according to claim 5, characterized in that: The specific steps for generating a first-level remediation candidate sequence by eliminating contact burden transfer modifications from the retained structure modifications based on changes in contact normal force and contact intrusion depth, forming a candidate contact closure sequence based on the remaining retained structure modifications, and canceling each one sequentially are as follows: For the single modification and candidate modification pairs in the retained structural modification set, the folded contact anchor chain is regenerated, and the contact normal force value before the original defect anchor position is modified is subtracted from the contact normal force value after modification to obtain the contact normal force reduction value; For the first contact point after the original defect anchor point that contains any corresponding packaging structure unit number, calculate the difference in contact normal force and the difference in contact penetration depth between the modified and unmodified points to obtain the increase in contact normal force and the increase in contact penetration depth. If the decrease in contact normal force is greater than zero, the sum of all positive increases in contact normal force is not less than the decrease in contact normal force, and any increase in contact penetration depth is greater than zero, delete the corresponding single modification or candidate modification pair. Based on the original defect anchor sequence, apply a single modification or candidate modification pair that has not been deleted to the current original defect anchor. If the defect normalization value of the current original defect anchor is not greater than zero after application, and no new defect anchor is generated with a folding stage number not greater than the folding stage number of the current original defect anchor, continue processing the next original defect anchor until all defect normalization values ​​are not greater than zero, forming a candidate contact closure sequence. Cancel individual modifications or candidate modification pairs in the candidate contact closure sequence one by one from back to front, in the execution order. If, after revocation, a defect normalization value greater than zero exists or any retained modification re-meets the deletion condition for contact burden transfer modification, the corresponding modification is restored; otherwise, the corresponding modification is deleted. After all revocations are completed, a first-level rectification candidate sequence is generated.

7. The packaging structure optimization method based on multi-objective decision-making according to claim 6, characterized in that: The specific steps for generating secondary performance improvement candidate sequences and tertiary replacement candidate sequences based on the remaining retained structure modification and the packaging structure template are as follows: For each first-level rectification candidate sequence, a retained structure modification that was not adopted is added; when all defect normalized values ​​are still not greater than zero after the addition, no contact burden transfer occurs, at least one target margin value increases and the remaining target margin values ​​do not decrease, a second-level performance improvement candidate sequence is generated. When there is no first-level rectification candidate sequence where the margin values ​​of all four objectives are not less than zero, the parametric die-cutting diagrams with product external dimensions and product weight values ​​within the applicable range are selected from the packaging structure template. The internal dimensions of the packaging and the positions of the tongue, slot, adhesive edge, locking bottom piece and indentation line are adjusted according to the product external dimensions and the lower limit of the clearance. The folded contact anchor chain is regenerated and the defect normalization value is calculated to generate a third-level alternative candidate sequence.

8. The packaging structure optimization method based on multi-objective decision-making according to claim 7, characterized in that: The specific steps for calculating the target margin values ​​of candidate sequences at each level and screening the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan are as follows: Target margin values ​​are calculated for each level of candidate sequence. The target margin values ​​include structural safety margin, remaining material cost, remaining production time, and operational margin. Candidate sequences with any target margin value less than zero are deleted. Candidate sequences at each level are arranged in descending order of the minimum value among the target margin values, and the first-ranked sequence at each level is determined as the first-level rectification plan, the second-level improvement plan, and the third-level alternative plan.

9. The packaging structure optimization method based on multi-objective decision-making according to claim 8, characterized in that: The specific steps for updating the corresponding die-cutting pattern and outputting the graded optimization scheme and editable optimized packaging die-cutting pattern after verification by folding the contact anchor chain are as follows: Update the baseline packaging die-cutting pattern according to the Level 1 rectification plan and Level 2 improvement plan, update the parameterized die-cutting pattern according to the Level 3 alternative plan, mark the modified boundaries and parameter changes in the updated die-cutting pattern, and generate the corresponding optimized packaging die-cutting pattern. Reread each optimized packaging die drawing, generate folded contact anchor chains, and recalculate defect normalization values ​​and target margin values; When the Level 1 rectification plan and Level 2 improvement plan do not involve contact burden transfer, all defect normalization values ​​are not greater than zero, and all target margin values ​​are not less than zero, output the corresponding hierarchical optimization plan and editable optimized packaging die drawing; When all defect normalized values ​​of the third-level alternative scheme are not greater than zero and the target margin values ​​are not less than zero, output the third-level alternative scheme and the editable optimized packaging die drawing; if any condition is not met, delete the corresponding scheme and read the next sorting result at the same level.

10. A packaging structure optimization system based on multi-objective decision-making, characterized in that, include: The module includes a folded anchor chain generation module, a dual-sequence anchor position solution module, a closed-loop hierarchical generation module, and a hierarchical decision write-back module, among which: The folding anchor chain generation module is used to obtain the reference packaging die drawing, packaging folding parameters and packaging structure allowable parameters, simulate the folding of packaging structure units step by step, determine the position where the non-directly connected packaging structure units first have surface contact as the first contact point and connect them to form a folding contact anchor chain, calculate the defect normalization value based on the first contact point and generate the original defect anchor position sequence, and generate candidate structure modification based on the original defect anchor positions. The dual-order anchor position solving module is used to apply two candidate structural modifications to the same original defect anchor position in reverse order, generate a positive dual-modification structure, a reverse dual-modification structure and a corresponding anchor position locking state, and filter and retain the structural modifications. The closed-level generation module is used to eliminate contact burden transfer modifications from the retained structure modifications based on changes in contact normal force and contact intrusion depth, form candidate contact closure sequences based on the remaining retained structure modifications and cancel them one by one, generate a first-level rectification candidate sequence, and generate a second-level performance improvement candidate sequence and a third-level replacement candidate sequence based on the remaining retained structure modifications and packaging structure template. The hierarchical decision-making write-back module is used to calculate the target margin value of each level of candidate sequence, screen the first-level rectification plan, the second-level improvement plan and the third-level alternative plan, update the corresponding die-cutting pattern, and output the hierarchical optimization plan and editable optimized packaging die-cutting pattern after verification by folding contact anchor chain.

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