PCB inner layer core plate punching alignment method and device and storage medium

Abstract

This application discloses a method, device, and storage medium for aligning punched holes in a PCB inner layer core board. The method includes obtaining the actual coordinates and theoretical reference coordinates of four Mark feature points on a single side; constructing a circular screening domain, and selecting the four corner points of an inscribed square parallel to the domain's axis as candidate points; calculating the cumulative offset of the four points on a single side corresponding to each candidate point as a compensation posture, and selecting the candidate point corresponding to the minimum value as the optimal target point; if the distance between the theoretical reference coordinates and the optimal target point is less than a precision threshold, outputting the compensation posture corresponding to the optimal target point as the alignment correction target; if it is not less than the threshold, iterating through the domain with the line connecting the two as the diameter until the distance is less than the precision threshold or the distance between two adjacent optimal target points is less than the platform's minimum executable step size, at which point the alignment correction target is output. This effectively adapts to the non-uniform expansion and contraction deformation of the board material, reduces local optima, and balances alignment accuracy and efficiency.

Description

Technical Field

[0001] This application relates to the field of printed circuit board (PCB) processing technology, and more specifically, to a PCB inner layer core board punching and alignment method, PCB punching and alignment equipment, and machine storage medium. Background Technology

[0002] In the PCB inner layer core board processing, the punching equipment must first perform precise alignment of the board material before punching. In existing technologies, visual positioning is typically used to achieve this alignment. Specifically, four Mark feature points are set on one side of the PCB inner layer core board. The actual coordinates of these four Mark feature points are acquired by an image acquisition device and compared with pre-stored theoretical reference coordinates. The current positional offset of the board material is calculated based on the coordinate deviation between the two. Then, the board material is moved by a servo platform to achieve posture correction. Once the board material is aligned to the target posture, the punching operation is performed.

[0003] However, the existing alignment methods described above have the following shortcomings. First, since only the position information of four Mark points on a single side is collected, the effective data dimension available for calculation is limited. In actual PCB manufacturing, the degree of deformation varies across different parts of the board due to multiple processes such as etching and lamination. Relying solely on four-point coordinates is insufficient to accurately describe the overall actual deformation state of the board. Second, existing technologies typically use a single calculation mode to process the coordinate data, limiting their adaptability to variations in board deformation. Third, when the posture obtained from a single calculation fails to meet accuracy requirements, the posture is usually adjusted by re-acquiring images and re-executing the complete calculation process. This process requires repeated image acquisition and data transmission, consuming significant time. Fourth, the servo platform itself has boundary constraints on its physical motion travel. The current calculation process lacks effective connection with the platform's actual motion capabilities, easily leading to situations where the theoretically calculated posture exceeds the platform's executable range, affecting alignment accuracy and operational stability. Fifth, the number of posture adjustment executions in existing solutions lacks deterministic control, resulting in significant fluctuations in alignment time between different boards, making it difficult to meet the stable cycle time requirements of mass production lines.

[0004] Therefore, how to make fuller use of existing data information and improve the accuracy and efficiency of alignment calculation under limited coordinate data conditions, and how to effectively match the theoretical calculation results with the actual execution capability of the servo platform and achieve reasonable control over the number of adjustments are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0005] The main objective of this application is to provide a PCB inner layer core board punching alignment method, PCB punching alignment equipment, and storage medium to solve the technical problems of existing alignment methods that rely on single fitting calculations, assume uniform deformation of the board material, are prone to getting stuck in local optima, cannot adapt to non-uniform expansion and contraction deformation, and have uncertain adjustment times, making it difficult to balance efficiency and accuracy. The application aims to achieve the goal of adapting to non-uniform deformation of the board material through a hierarchical and step-by-step shrinking convergence mechanism, reducing local optima, and balancing alignment accuracy and efficiency.

[0006] To achieve the above objectives, the first aspect of this application proposes a PCB inner layer core board punching alignment method, comprising the following steps: S1: Obtain the actual coordinates and corresponding theoretical reference coordinates of four Mark feature points on one side of the PCB inner layer core board; S2: Construct a circular screening domain using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates relative to the theoretical reference coordinates under the current posture as the screening radius; take the four corner points of the inscribed square parallel to the axis of the circular screening domain as candidate points, each candidate point representing a candidate alignment posture; S3: Take each candidate point as the current compensation posture of the PCB inner layer core board, calculate the sum of the linear offset distances of the actual coordinates of the four Mark feature points on one side under the compensation posture relative to their respective corresponding theoretical reference coordinates, and use this as the cumulative offset value of the four points on one side corresponding to each candidate point; take the candidate point corresponding to the minimum cumulative offset value as the current screening domain. S4: Determine whether the distance between the theoretical reference coordinates and the optimal target point is less than the preset accuracy threshold; S51: If it is less, then use the compensation posture corresponding to the current optimal target point as the alignment correction target; S52: If it is not less, then use the connection length between the theoretical reference coordinates and the current optimal target point as the diameter of the new circular screening domain, take the midpoint of the connection line as the new screening center, take the four corner points of the inscribed square parallel to the axis of the new screening domain as the new round of candidate points, determine the minimum new offset cumulative value of each new round of candidate points, repeat step S4 until the distance between the current optimal target point and the theoretical reference coordinates is less than the preset accuracy threshold, and output the compensation posture corresponding to the current optimal target point as the alignment correction target; or, when the distance between the optimal target points obtained by two adjacent iterations is less than the minimum executable step of the three-axis servo attitude adjustment platform, output the compensation posture corresponding to the current optimal target point as the alignment correction target.

[0007] In the above scheme, the method for calculating the cumulative total of four-point offset on a single surface includes: calculating the Euclidean distance between the actual coordinates of the four Mark feature points on a single surface and their respective theoretical reference coordinates, and summing the four Euclidean distance values ​​to obtain the cumulative total of four-point offset on a single surface under the compensated attitude.

[0008] In the above scheme, when the distance between the optimal target points obtained from two adjacent iterations is less than the minimum executable step size of the three-axis servo attitude adjustment platform, the compensation attitude corresponding to the current optimal target point is output as the alignment and correction target. This includes: if the distance between the optimal target points obtained from two adjacent iterations in a single attitude is less than the minimum executable step size of the three-axis servo attitude adjustment platform, and the distance between the theoretical reference coordinates and the optimal target point still does not meet the requirement of being less than a preset accuracy threshold, then the three-axis servo attitude adjustment platform is controlled to fine-tune the overall attitude of the inner core board of the PCB, and step S1 is re-executed in the adjusted attitude until the optimal compensation attitude corresponding to the distance between the theoretical reference coordinates and the optimal target point being less than the preset accuracy threshold is selected.

[0009] In the above scheme, the method further includes: if the number of times the three-axis servo attitude adjustment platform adjusts the overall attitude of the PCB inner core board exceeds the preset number, and the distance between the theoretical reference coordinate and the optimal target point still does not meet the requirement of being less than the preset accuracy threshold, then an out-of-tolerance alarm is triggered and the diversion mechanism is linked to discharge the PCB inner core board.

[0010] In the above scheme, obtaining the actual coordinates and corresponding theoretical reference coordinates of four Mark feature points on one side of the PCB inner core board includes: synchronously acquiring target images of the upper and lower surfaces of the PCB inner core board by using eight CCD cameras deployed on the upper and lower sides of the PCB inner core board, and extracting the actual coordinates of four Mark feature points on each of the upper and lower surfaces after image preprocessing.

[0011] In the above scheme, after outputting the compensation posture corresponding to the current optimal target point as the alignment and correction target, the method further includes: generating the independent whole-board compensation amount for the upper board surface and the independent whole-board compensation amount for the lower board surface based on the optimal compensation postures obtained by solving the upper board surface and the lower board surface respectively; determining the independent fine alignment compensation amount for the upper board surface and the independent fine alignment compensation amount for the lower board surface corresponding to the product specification information of the current PCB; superimposing the whole-board compensation amount for the upper board surface and the independent fine alignment compensation amount for the upper board surface to generate the final compensation amount for the upper board surface; superimposing the whole-board compensation amount for the lower board surface and the independent fine alignment compensation amount for the lower board surface to generate the final compensation amount for the lower board surface.

[0012] In the above scheme, constructing a circular screening domain using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates as the screening radius includes at least one of the following: calculating the offset distance between the actual coordinates of each Mark feature point and the corresponding theoretical reference coordinates; if any offset distance does not exceed a preset warning threshold, then using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates as the screening radius to construct a circular screening domain; calculating the lateral offset difference and the longitudinal offset difference between the actual coordinates of the same source Mark feature points on the upper and lower surfaces respectively; if the lateral offset difference or the longitudinal offset difference does not exceed a preset warning threshold... i If the deformation threshold is set, then the theoretical reference coordinates are used as the screening center, and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates is used as the screening radius to construct a circular screening domain.

[0013] In the above scheme, after outputting the compensation posture corresponding to the current optimal target point as the alignment and correction target, the method further includes: archiving the actual coordinates, cumulative offset value, optimal target point, compensation posture and good / bad judgment results during the alignment process, obtaining layer offset feedback data through bidirectional data interaction with the backend X-Ray detection equipment, and adaptively adjusting the preset accuracy threshold and / or the screening radius according to the layer offset feedback data.

[0014] To achieve the above objectives, a second aspect of this application proposes a PCB punching and alignment device, including a processor and a memory storing a computer program, wherein when the processor runs the computer program, it implements the steps of any of the above-described PCB inner layer core board punching and alignment methods.

[0015] To achieve the above objectives, a third aspect of this application proposes a machine storage medium storing a computer program, which, when executed by a processor, implements the steps of the PCB inner layer core board punching and alignment method described above.

[0016] The technical solutions provided by the embodiments of this application may include the following beneficial effects: In this application, firstly, by constructing a circular sieving domain and iteratively shrinking the domain step by step, the candidate points continuously converge towards the theoretical reference coordinates. As the diameter of the sieving domain decreases in each iteration, the coverage area of ​​the corresponding candidate points narrows synchronously, and the distance between the target point and the reference point gradually approaches a preset accuracy threshold. This mechanism enables the optimal target point to approach the theoretical reference position, providing a technical path to progressively approach the target position within a limited number of iterations, which is beneficial for improving alignment accuracy. Secondly, by using only four corner points as candidate points in a single pose, only four cumulative sums need to be calculated in each iteration, and the acquired coordinate data is reused to complete subsequent calculations, eliminating the need to re-acquire images. Compared to exhaustive search schemes, the computational load is significantly reduced, which helps shorten the alignment calculation time for a single board piece; thirdly, by using the cumulative total offset of four points on a single face as the attitude evaluation index, the impact of data anomalies at a single point on the cumulative total is limited, thus enabling the calculation results to have fault tolerance for single-point data deviations. Simultaneously, this index comprehensively reflects the overall offset of the four points on a single face, ensuring that the selection of the optimal target point is based on global optimal evaluation, which helps reduce alignment deviations caused by local deformation under a single reference point alignment method, enhancing the algorithm's adaptability to boards with different deformations; Furthermore, by setting a termination condition where the distance between the optimal target points of two adjacent rounds is less than the platform's minimum executable step distance, the algorithm's output compensation posture is ensured to be within the actual executable physical travel range of the servo platform. This reduces situations where the algorithm idles or the platform fails to reach its position due to a mismatch between the theoretical output value and the physical capabilities of the actuator, ensuring the feasibility of the solution in actual production lines. Finally, if the initial screening meets the standards, the posture is directly output without additional posture fine-tuning or image resampling. If the standards are not met, convergence is achieved through iterative narrowing under the same posture data, reducing repeated image resampling. The overall process adaptively distributes traffic based on the convergence status, which is beneficial for balancing the alignment efficiency of plates with different degrees of deformation and adapting to the stable cycle requirements of mass production lines.

[0017] Therefore, this application embodiment uses a hierarchical, step-by-step domain shrinking convergence mechanism to make candidate points gradually approach the theoretical benchmark position, which can approach the preset accuracy threshold within a finite number of iterations; it uses the cumulative value of four-point offset as the evaluation index, which has redundant fault tolerance capability for single-point coordinate deviation; it reuses the acquired coordinate data to complete the domain shrinking iteration under the same posture, without the need to repeatedly collect images; and it uses mechanical limit termination conditions to ensure that the output posture is within the physical range that the actuator can actually reach, taking into account both micron-level alignment accuracy and the feasibility of actual production line implementation. Attached Figure Description

[0018] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1A schematic flowchart illustrating the PCB inner layer core board punching and alignment method provided in this application embodiment; Figure 2 This is a schematic diagram of the PCB punching and alignment device provided in an embodiment of this application. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0022] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linked," and "socketing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] It should be noted that the embodiments of this application can be applied to the field of visual alignment in the punching process of PCB inner core boards. For example, by deploying a single-sided four-CCD imaging module, a three-axis servo attitude adjustment platform, and an industrial control host on the production line of the PCB punching process, the images of the four corners of the PCB board on the conveying path and the real-time pose data of the platform are obtained. Using the method of this application, a circular screening domain is constructed with the theoretical reference coordinates as the screening center. The four corner points of the inscribed square parallel to the axis of this domain are taken as candidate alignment postures. The cumulative value of the single-sided four-point offset corresponding to each candidate posture is calculated one by one, and the optimal target point is screened. Through step-by-step domain shrinking iteration, the optimal target point is gradually converged to the theoretical reference coordinates. Finally, the alignment control parameters containing the attitude correction amount are output to drive the actuator to complete the punching positioning. This aims to replace the technical limitations of the traditional single-fit alignment method, which is difficult to balance accuracy and efficiency and has insufficient adaptability to non-uniform deformation of the board material.

[0025] Understandably, existing solutions face the following technical challenges in achieving high-precision punching alignment for PCB inner core boards. First, traditional methods typically employ a single-step fitting calculation, calculating compensation parameters based on the currently acquired four-point coordinates. This lacks a mechanism for verifying and correcting the validity of the calculation results. When the board exhibits localized non-uniform deformation, the single-step fitting is prone to deviating from the global optimum, leading to substandard alignment accuracy and necessitating re-image acquisition and recalculation, increasing the alignment time per board. Second, when the posture obtained from a single fitting fails to meet accuracy requirements, existing solutions typically require re-triggering image acquisition and repeating the entire coordinate extraction and fitting calculation process. This iterative process involves image transmission and processing, increasing the processing time per board and making it difficult to adapt to the stable cycle time requirements of mass production lines. Furthermore, the traditional calculation process is not integrated with the actual physical travel capability of the servo platform, and the theoretical compensation amount may exceed the platform's execution range, causing alignment deviations. Simultaneously, existing solutions lack deterministic control over the number of posture adjustment executions, resulting in significant fluctuations in alignment time between different boards, which is detrimental to the unified management of production line cycle time.

[0026] Based on this, the embodiments of this application aim to provide a PCB inner layer core board punching alignment method. Through a hierarchical convergence mechanism of screening domain initialization, step-by-step domain shrinking iteration and dual termination judgment, the optimal compensation posture is approximated within a limited iterative calculation, so that the theoretical calculation results match the actual execution capability of the platform, taking into account both micron-level alignment accuracy and production line mass production efficiency, and improving the positioning stability and product yield of the PCB punching process.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Figure 1 This is a flowchart illustrating the PCB board alignment method provided in the embodiments of this application, as shown below. Figure 1 As shown, the method, applied to a PCB punching and alignment device, includes: Step S1: Obtain the actual coordinates and corresponding theoretical reference coordinates of the four Mark feature points on one side of the inner core board of the PCB.

[0029] It should be noted that this method is executed by a PCB punching alignment device, which typically includes an industrial control host, a vision imaging module, a three-axis servo attitude adjustment platform, and a punching execution mechanism. The industrial control host, as the core control unit, is responsible for running the program instructions of the PCB inner layer core board punching alignment method described in this application embodiment; the vision imaging module (such as a CCD camera) is used to acquire target images of the PCB inner layer core board; the three-axis servo attitude adjustment platform is used to adjust the board posture according to the alignment result; and the punching execution mechanism is used to perform the punching operation after alignment is completed.

[0030] A PCB (Printed Circuit Board) serves as the support and electrical connection carrier for electronic components. The inner core of a PCB refers to the substrate inside a multilayer PCB used to form the inner layer circuitry. Its surface is covered with copper foil, which is etched to form the inner conductive patterns. In the manufacturing process of multilayer PCBs, the core is usually used as the starting layer. Prepreg (PP) sheets and outer copper foil are alternately stacked on both sides of the core and then laminated to form a multilayer board structure. A multilayer PCB is made by laminating multiple inner cores, and the conductor patterns on each core layer need to maintain a precise alignment. To achieve interlayer alignment, the inner cores need to be punched before lamination, and these punched holes serve as positioning references for subsequent lamination processes. Therefore, precise positioning of the inner cores during the punching process is a prerequisite for ensuring the interlayer alignment accuracy of the multilayer board.

[0031] Among them, Mark feature points, also known as fiducial marks, markers, or optical positioning points, are specially designed, high-contrast position identification marks on the PCB board. The function of Mark feature points is to provide a common, measurable reference point for the vision system of automated equipment, enabling the equipment to accurately locate the position of the PCB board.

[0032] For example, the Mark feature points are preferably circular marks, such as solid copper circles with a diameter of 1 mm (±0.2 mm), smooth and neat edges, and a color that is clearly different from the surrounding background. The Mark feature points are usually set near the four corners of the PCB board, with the four points located diagonally along the PCB and as far apart as possible.

[0033] It is understood that the "four Mark feature points on one side" mentioned in step S1 refers to four Mark feature points set on one side of the PCB inner core board (i.e., the side facing the CCD camera of the punching equipment), located in the four corner areas of the board. The spatial distribution of these four feature points constitutes the geometric reference describing the current placement posture of the board.

[0034] The actual coordinates refer to the physical coordinates of the four Mark feature points on one side of the PCB inner layer core board, acquired by the vision imaging system, within the device's unified world coordinate system. Specifically, after the CCD camera acquires an image of the PCB inner layer core board, the industrial control host performs image preprocessing (including grayscale conversion, filtering and noise reduction, edge extraction, etc.) on the acquired target image to identify the image position of each Mark feature point (represented by pixel coordinates). Subsequently, using a multi-camera unified world coordinate calibration method, that is, using pre-calibrated camera parameters and coordinate transformation matrices, the pixel coordinates of each Mark feature point are transformed to the device's unified world coordinate system to obtain physical coordinate values ​​in millimeters. For example, the actual coordinates reflect the true position of the four Mark feature points on the PCB inner layer core board in the device space under the current placement posture. Due to potential positional deviations during the transport and placement of the board material, there is usually a certain offset between the actual coordinates and the theoretical positions.

[0035] The theoretical reference coordinates refer to the standard coordinate values ​​of the four Mark feature points on a single side of the PCB inner layer core board in the unified world coordinate system of the device under ideal alignment (i.e., when the board is in a standard placement posture). For example, the theoretical reference coordinates are obtained as follows: a standard PCB reference template (i.e., an ideal template whose size and graphics meet the design requirements) is selected and placed on the device platform in a standard posture. The Mark feature point image of the template surface is acquired through a vision imaging system. After coordinate calibration and conversion, the coordinate values ​​of the four Mark feature points in this standard posture are obtained and stored as the theoretical reference coordinates. These four theoretical reference coordinates together constitute a reference system describing the standard placement posture of the board. Here, the theoretical reference coordinates serve as a reference for the subsequent screening and alignment algorithm, used to compare with the actual coordinates obtained in step S1 to calculate the degree of offset of the board's current posture relative to the standard posture.

[0036] Thus, step S1 acquires the actual coordinates of four Mark feature points on one side of the PCB inner core board using a vision imaging system, and obtains the corresponding pre-stored theoretical reference coordinates, providing basic data for subsequent steps. The deviation between these four actual coordinates and the four theoretical reference coordinates reflects the difference between the current board posture and the standard posture, serving as the data basis for subsequent screening domain construction, candidate point generation, and optimal posture selection.

[0037] Step S2: Using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates under the current posture relative to the theoretical reference coordinates as the screening radius, construct a circular screening domain; take the four corner points of the inscribed square parallel to the axis of the circular screening domain as candidate points, and each candidate point represents a candidate alignment posture.

[0038] Here, the screening center refers to the center position of the circular screening area. For example, the screening center is one of the four theoretical reference coordinates obtained in step S1. The specific coordinate selected can be determined by the number of the Mark feature point (for example, selecting the theoretical reference coordinate corresponding to Mark point 1 as the screening center). The reason for selecting the theoretical reference coordinate as the screening center is that it reflects the ideal position of the Mark feature point when the plate is in a standard alignment posture. Using this position as the reference center for the search aligns with intuitive understanding; that is, the greater the actual position offset, the wider the search area needs to be.

[0039] The screening radius refers to the distance from the screening center to the boundary of the circular screening domain. For example, the screening radius is the offset distance of the actual coordinates of the Mark feature point corresponding to the screening center relative to the theoretical reference coordinates in the current posture; that is, the Euclidean distance between the actual and theoretical positions. The value of this radius directly reflects the degree of offset of the Mark feature point in the current posture: the larger the offset, the larger the screening radius and the wider the coverage of the screening domain; the smaller the offset, the smaller the screening radius and the narrower the coverage of the screening domain.

[0040] The screening domain is a circular area constructed with the screening center as the center and the screening radius as the radius. Geometrically, the screening domain represents the spatial range that a Mark feature point might pass through or fall into as it shifts from its theoretical reference position to its actual position under the current plate posture. This circular area is subsequently used to generate candidate points. It should be noted that the screening domain is constructed using a single-point offset distance as the screening radius, rather than a four-point combined offset, to ensure a deterministic correspondence between the center and boundaries of the screening domain and the actual physical state, providing a clear mathematical basis for the subsequent geometric convergence of the progressively narrowing domain.

[0041] Candidate points refer to specific locations selected from within the screening domain for evaluating the quality of each posture. For example, candidate points are the four corner points of an axis-inscribed square within a circular screening domain. This application uses the four corner points of an axis-inscribed square as candidate points because: the screening domain itself is circular, and each point on the circumference represents an offset in a certain direction relative to the center (theoretical reference coordinates). Searching for the optimal offset direction across the entire circumference would theoretically involve an infinite amount of computation. By taking an axis-inscribed square within the circular screening domain, the four corner points of the square represent the offset (and combinations thereof) in four extreme directions: horizontal to the right, horizontal to the left, vertical upward, and vertical downward. In other words, these four corner points cover the four extreme positions on the boundary of the screening domain, representing four extreme offset schemes. After determining the optimal corner points, the square size is reduced by progressively shrinking the domain, causing the corner points to gradually approach the center, thereby achieving rapid convergence of the optimal point.

[0042] The alignment posture refers to the spatial pose of the inner PCB core board on the equipment platform, specifically including three degrees of freedom: translational deviation along the X-axis, translational deviation along the Y-axis, and rotation angle in the XY plane (usually represented by θ). In this embodiment, each candidate point (i.e., a corner point of an inscribed square) represents a candidate alignment posture. The changes in the coordinates of the candidate point (the offset direction and amount relative to the screening center) correspond to different adjustment schemes when the platform compensates for the board posture. That is, the offset of the candidate point relative to the screening center represents the compensation direction and compensation magnitude when adjusting the current actual posture of the board to the posture corresponding to the candidate point.

[0043] Thus, step S2 constructs a circular screening domain with the theoretical reference coordinates as the screening center and the actual offset distance of a single point as the radius, and extracts the four corner points of the axis-parallel inscribed square within this domain as candidate points. This step transforms the infinite continuous spatial search problem into a finite discrete point evaluation problem by "determining the screening range with the offset distance of a single point and extracting a finite number of candidate points with the inscribed square," providing a data foundation for the efficient screening in the subsequent step S3.

[0044] Step S3: Using each candidate point as the compensation posture of the current PCB inner layer core board, calculate the sum of the linear distances of the actual coordinates of the four Mark feature points on one side under the compensation posture relative to their respective theoretical reference coordinates, and use it as the cumulative value of the single-side four-point offset corresponding to each candidate point; take the candidate point corresponding to the minimum cumulative offset value as the optimal target point in the current screening domain.

[0045] The compensation posture refers to the spatial pose state achieved after adjusting the board's position according to the direction and magnitude indicated by a candidate point, based on the board's actual placement posture. Specifically, the four candidate points determined in step S2 are the four corner points of a square inscribed in a circular screening domain. Each corner point has a definite offset direction and offset amount relative to the screening center (i.e., the theoretical reference coordinates). Using this candidate point as the compensation posture means that, assuming the Mark feature point of the current PCB inner layer core board is adjusted from its actual position to the candidate point position, the posture of the entire board will undergo corresponding translation and / or rotation changes, forming a hypothetical alignment posture. Step S3 then evaluates each of these four hypothetical compensation postures, calculating the alignment effect index under each posture.

[0046] Here, the offset straight-line distance refers to the Euclidean distance between the actual coordinates of a single Mark feature point and its corresponding theoretical reference coordinates in a given posture. For example, in the actual production of PCB inner layer core boards, due to the influence of multiple processes such as etching, lamination, high-temperature baking, and stress release, the offsets of the four Mark feature points relative to their theoretical reference positions are usually different. Traditional single-point evaluation methods only focus on the offset of a single Mark point, which cannot comprehensively reflect the overall deformation state of the entire board. To avoid this limitation, this application adopts a comprehensive evaluation strategy of the offsets of four Mark points. For example, let the current posture be... i The actual coordinates of the Mark feature points are (x) i， y i ), whose corresponding theoretical reference coordinates are (x 0i y 0i ), then the first iThe linear distance of the offset of each Mark feature point L i Calculate as follows: Calculate the difference between the actual coordinates and the theoretical reference coordinates of the point in the X and Y directions respectively, then take the square root of the sum of the squares of the two differences to obtain the linear offset distance of the point. L i . Specifically, L i = √[(x i - x 0i )² + (y i - y 0i )²] The magnitude of this distance directly reflects the degree to which the Mark feature point deviates from its theoretical position in the current pose. Li A smaller value indicates that the point is closer to its theoretical position, and vice versa.

[0047] Among them, the cumulative value of the four-point offset on a single surface L sum This refers to the summation of the linear offset distances of the four Mark feature points on a single surface under a given candidate compensation pose. L sum = Σ L i ,in i =1, 2, 3, 4. It is understandable that this cumulative total value serves as the sole criterion for evaluating the quality of a particular orientation in this application. Its technical significance lies in the fact that the linear offset distance of a single Mark point only reflects the degree of deviation of that point itself, while the sum of the linear offset distances of the four points comprehensively reflects the overall deviation of the four corner areas of a single side of the entire PCB inner core board relative to its theoretical position. It should be noted that this invention does not use single-point offset as the criterion for evaluation, but rather calculates the cumulative linear offset distances of the four Mark feature points on a single side relative to their corresponding theoretical reference points under the same orientation, using the total offset value as the sole criterion for evaluating the quality of the orientation. The smaller the cumulative total value, the closer the four Mark feature points under the compensated orientation are to their respective theoretical reference positions, meaning the overall alignment performance of the orientation is superior.

[0048] For example, assuming that in a certain candidate pose, the linear offset distances of the four Mark feature points are 0.003mm, 0.005mm, 0.004mm, and 0.006mm respectively, then the cumulative total value of the single-plane four-point offsets corresponding to this pose is 0.003 + 0.005 + 0.004 + 0.006 = 0.018mm; if in another candidate pose the linear offset distances of the four Mark points are 0.008mm, 0.007mm, 0.009mm, and 0.008mm respectively, then its cumulative total value is 0.032mm. The former is judged as the better pose because its cumulative total value is smaller.

[0049] The optimal target point refers to the candidate point among the four candidate points within the current screening domain that minimizes the cumulative offset of the four points on a single side. This point is recorded as the optimal target point for this round of screening. P n .

[0050] For example, in step S3, the cumulative offset of the four candidate points on one side is calculated for each of the four candidate points in step S2, resulting in four cumulative values. By comparing these values ​​laterally, the candidate point with the smallest value is identified, and this smallest value is the optimal target point within the current screening domain. Specifically, by comparing the total offset values ​​of each point laterally, inferior points with large offsets are eliminated, and the optimal point within the current screening domain is determined and recorded as the target point. P 1.

[0051] It should be noted that the determination of the optimal target point has a dual significance: on the one hand, the compensation posture corresponding to this point is the one with the best overall alignment performance among the four candidate postures in the current sieving domain. If it meets the preset accuracy requirements, it will be directly used as the final alignment and correction target output; on the other hand, if it does not meet the accuracy requirements, the optimal target point will be used as the reference point for the next round of domain narrowing iteration, that is, connecting the theoretical reference coordinates with the current optimal target point, and constructing a new domain narrowing sieving domain with this line as the diameter, so as to achieve the gradual narrowing of the sieving range.

[0052] Thus, step S3, by replacing the single-point offset with the sum of the four points as the attitude evaluation index, transforms the local evaluation of the single-point offset into a comprehensive global evaluation of the four points, effectively avoiding alignment deviations caused by anomalies or local deformations of a single Mark point. Simultaneously, this step uses the four candidate points provided in step S2 as the selection criteria, determining the optimal target point within the current selection domain through a finite number of calculations, avoiding infinite searches in continuous space, and laying a data foundation for rapid convergence in subsequent steps.

[0053] In some implementations, the method for calculating the cumulative total of four-point offsets on a single surface includes: Calculate the Euclidean distance between the actual coordinates of the four Mark feature points on a single surface and their corresponding theoretical reference coordinates. Sum the four Euclidean distance values ​​to obtain the cumulative value of the four-point offset on a single surface under the compensated posture.

[0054] Specifically, to adapt to the differentiated offset characteristics of the four corner Marks on a single face, this application does not use single-point offset as the screening criterion. Instead, it calculates the sum of the linear distances of the offsets of the four Mark feature points on a single face relative to the corresponding theoretical reference points under the same posture, and uses the total offset value as the sole screening index for posture quality. The formula is as follows:

[0055] In the formula: is the linear offset distance of the i-th actual Mark feature point relative to the theoretical reference point; This represents the total offset distance of four points on a single side of the entire board. The smaller the value, the better the overall alignment performance of the current posture. Meanwhile, based on the theoretical benchmark... The straight-line distance from the iterative optimal attitude point is used as the criterion for determining the final convergence of the screening operation.

[0056] In the embodiments of this application, the actual deviation of each Mark point is quantified by Euclidean distance and summed, and the local offset information of a single point is integrated into a comprehensive evaluation index that reflects the overall alignment deviation of the board, making the judgment of posture quality more objective and reliable.

[0057] Step S4: Determine whether the distance between the theoretical reference coordinates and the optimal target point is less than the preset accuracy threshold.

[0058] The preset accuracy threshold is a pre-defined distance threshold used to determine whether the alignment accuracy meets the standard. This threshold represents the maximum allowable alignment deviation in the PCB inner layer core board punching process, and its value directly determines the accuracy level of the punching alignment. In this embodiment, the specific value of the preset accuracy threshold can be entered by the staff through the human-machine interface during the process parameter configuration stage, according to different product grades, customer order requirements, and equipment capabilities. It can be understood that the technical meaning of the preset accuracy threshold is: when the distance between the optimal target point and the theoretical reference coordinates is less than the threshold, it indicates that the Mark feature point is close enough to its theoretical reference position under the current compensation posture, the accuracy gain brought by the continued shrinking iteration is not significant, and the overall comprehensive alignment performance of the four Mark feature points under the current compensation posture meets the process requirements, so the screening can be terminated and the posture can be output for punching operation; conversely, when the distance is greater than or equal to the threshold, it indicates that the accuracy of the current compensation posture does not yet meet the process requirements, and it is necessary to further approach the theoretical reference position through shrinking iteration.

[0059] For example, if the preset accuracy threshold is 0.02mm (i.e. 20μm), the distance between the optimal target point determined in step S3 and the theoretical reference coordinates is calculated to be 0.008mm. Since 0.008mm < 0.02mm, the distance is less than the preset accuracy threshold, and the alignment accuracy has been met. The process jumps to step S51 to output the correction target. If the distance is calculated to be 0.035mm, since 0.035mm ≥ 0.02mm, the distance is not less than the preset accuracy threshold, and the alignment accuracy has not been met. The process jumps to step S52 to perform the shrinkage iteration.

[0060] Step S51: If it is less than, then the compensation posture corresponding to the current optimal target point is used as the alignment and correction target.

[0061] Step S52: If it is not less than, then take the length of the line connecting the theoretical reference coordinates and the current optimal target point as the diameter of the new circular screening area, take the midpoint of the line as the new screening center, take the four corner points of the inscribed square parallel to the axis of the new screening area as the new round of candidate points, determine the minimum new offset cumulative value of each new round of candidate points, repeat step S4 until the distance between the current optimal target point and the theoretical reference coordinates is less than the preset accuracy threshold, and output the compensation attitude corresponding to the current optimal target point as the alignment correction target; or, when the distance between the optimal target points obtained by two adjacent iterations is less than the minimum executable step of the three-axis servo attitude adjustment platform, output the compensation attitude corresponding to the current optimal target point as the alignment correction target.

[0062] In some implementations, when the distance between the optimal target points obtained from two adjacent iterations is less than the minimum executable step size of the three-axis servo attitude adjustment platform, the compensated attitude corresponding to the current optimal target point is output as the alignment correction target, including: If the distance between the optimal target points obtained from two adjacent iterations in a single attitude is less than the minimum executable step of the three-axis servo attitude adjustment platform, and the distance between the theoretical reference coordinates and the optimal target point still does not meet the requirement of being less than the preset accuracy threshold, then the three-axis servo attitude adjustment platform is controlled to fine-tune the overall attitude of the inner core board of the PCB, and step S1 is re-executed in the adjusted attitude until the optimal compensation posture corresponding to the distance between the theoretical reference coordinates and the optimal target point being less than the preset accuracy threshold is selected.

[0063] In some embodiments, the method further includes: if the number of times the three-axis servo attitude adjustment platform adjusts the overall attitude of the PCB inner core board exceeds a preset number, and the distance between the theoretical reference coordinate and the optimal target point still does not meet the requirement of being less than a preset accuracy threshold, then an out-of-tolerance alarm is triggered and the diversion mechanism is linked to discharge the PCB inner core board.

[0064] In the out-of-tolerance alarm, "out of tolerance" is short for "exceeding tolerance," which means that the actual measured value or processing result exceeds the preset allowable deviation range (i.e., tolerance zone). When the tolerance of a certain parameter is ±0.02mm, if the measured deviation reaches 0.035mm, it constitutes out of tolerance.

[0065] Here, the out-of-tolerance alarm refers to a device-level anomaly warning mechanism triggered when the inner layer core board of a PCB still fails to meet the preset accuracy threshold after multiple orientation adjustments. This mechanism generates an alarm signal through the industrial control host, driving the audible and visual alarm to issue an audible and visual warning. At the same time, it displays the reason for the out-of-tolerance error and the corresponding board number on the human-machine interface to inform the production line operators that the current board has an uncorrectable deformation defect that requires manual intervention.

[0066] The diversion mechanism refers to the mechanical actuators installed on the conveying path of the PCB punching equipment, which are used to separate and discharge the unqualified boards from the main conveying channel to prevent them from continuing to flow into subsequent processes.

[0067] For example, the diversion mechanism is integrated into the sheet material conveying and diversion module, specifically including a defective sheet material pusher component and a limit stop. When an out-of-tolerance alarm is triggered, the industrial control host sends a discharge command to the diversion mechanism. The limit stop activates to prevent the defective sheet material from continuing to be conveyed forward, and the defective sheet material pusher component pushes the sheet material to the defective product collection area in a direction perpendicular to the conveying direction, thereby completing the automated diversion of defective sheet material.

[0068] Understandably, the interaction between the two is as follows: the out-of-tolerance alarm is an information-level response, informing operators that an uncorrectable anomaly has occurred, requiring manual confirmation and handling; the diversion mechanism is a physical execution-level response, separating and discharging defective boards from the normal processing flow, preventing them from continuing into subsequent processes such as pressing and causing the entire board to be scrapped. Working together, they achieve closed-loop management of defective boards.

[0069] For example, the preset number of times can be 6.

[0070] Specifically, a single screening operation refers to a complete closed-loop process of pure computation, based on the collected image data, to complete the initialization of the screening area, feature point calculation, screening of inferior postures, and dynamic updating of the screening area under a fixed plate placement posture. The specific execution steps are as follows: (1) Initialize the sieving domain: based on the preset theoretical benchmark. Using the screening center as the center, and the linear offset distance of the actual Mark feature point relative to the theoretical reference point under the current plate posture as the screening radius, a circular screening domain is constructed; the axis-parallel inscribed square corresponding to the circular screening domain is solved, and the geometric feature points at the four corners of the square are defined as the set of candidate points to be screened.

[0071] (2) First round of attitude screening: Based on the previously completed synchronous acquisition of upper and lower plate image data, calculate the corresponding geometric feature points of each candidate geometric feature point one by one. Numerical analysis; by comparing the total offset of each point horizontally, inferior points with large offsets are eliminated, and the optimal point within the current screening domain is determined and recorded as the target point. Testing various theoretical benchmarks. and corresponding target point If the straight-line distances meet the preset accuracy convergence thresholds, then the current round of screening will end directly.

[0072] (3) Iterative narrowing of the sieving domain: If the first round of sieving results does not meet the accuracy standard, the sieving domain parameters are dynamically updated: connect the reference origin. The optimal target point retained from the previous stage The length of the line segment is taken as the diameter of the new circular screening area; the midpoint of the line segment is taken as the screening center of the updated screening area, and the screening radius is half the length of the line segment. The inscribed square and the four corner geometric feature points of the new screening area are solved again. The offset calculation and point selection are repeated using the existing image data to obtain the optimal target point for the new stage. .

[0073] (4) Screening termination condition: The operation process of updating the screening domain, sampling geometric feature points, eliminating inferior postures, and retaining the optimal posture is executed in a loop to continuously shrink the screening range and make the optimal posture gradually converge to the theoretical reference point. When the distance between the optimal target point and the theoretical reference point is less than the preset accuracy convergence threshold or the iteration reaches the mechanical convergence limit of the current posture, the screening operation of all levels in this round is terminated immediately, and the point is the optimal processing posture under the current posture.

[0074] After the pre-alignment and coarse adjustment of the board material, the system completes a double-sided image acquisition and initializes the screening domain. It then initiates multi-level iterative calculations under the same orientation, continuously compressing the screening range until the mechanical convergence limit of that orientation is reached. If the accuracy tolerance is still not met after reaching the mechanical limit, the current board material orientation is deemed to have limitations. The system issues a command to control the three-axis servo platform to complete the overall orientation adjustment, and re-acquires images and initializes the screening domain. This process is recorded as one complete orientation adjustment cycle. After orientation adjustment, the single screening operation is restarted, repeatedly executing orientation adjustment and screening until the optimal processing orientation that meets the accuracy requirements is selected. Combining the mechanical and physical properties of the servo equipment with the actual deformation range of the PCB board material, extensive mass production testing has verified that this orientation adjustment cycle can achieve accuracy convergence in a maximum of 6 iterations, eliminating the need for an unlimited number of calculations.

[0075] In this embodiment, a complete closed-loop control logic of "iteration termination → multi-round attitude adjustment → out-of-tolerance rejection" is formed. Specifically, when the mechanical convergence limit is not met in a single attitude iteration, the three-axis servo platform is actively triggered to fine-tune the body attitude and re-execute the acquisition and screening process. This provides another opportunity for optimization for materials that cannot converge due to the inherent limitations of the current placement attitude, avoiding material waste caused by direct rejection. Furthermore, an upper limit is set for the number of attitude adjustments. When the target is still not met after exceeding this limit, an out-of-tolerance alarm is triggered, and material diversion and discharge are linked. This prevents infinite loop calculations and ineffective processing of materials with extreme deformation, while ensuring the determinism of the production line cycle time. Through the above mechanism, this embodiment pursues micron-level alignment accuracy while also considering the controllability of production line efficiency and the automated handling capability of abnormal materials, forming a closed-loop alignment system that unifies accuracy assurance, efficiency optimization, and cost control.

[0076] In some implementations, obtaining the actual coordinates and corresponding theoretical reference coordinates of four Mark feature points on a single side of the PCB inner layer core board includes: Eight CCD cameras deployed on the upper and lower sides of the PCB inner core board synchronously acquire target images of the upper and lower surfaces of the PCB inner core board. After image preprocessing, the actual coordinates of four Mark feature points on each of the upper and lower surfaces are extracted.

[0077] In this embodiment, the PCB punching and alignment equipment is equipped with four sets of industrial CCD cameras above and below the conveying path of the inner PCB core board, totaling eight imaging units. The four upper CCD cameras are used to acquire target images on the surface of the inner PCB core board, while the four lower CCD cameras are used to acquire target images on the lower surface. Each CCD camera is equipped with a high-resolution lens and a ring-shaped supplementary light source. The light source can adopt a low-angle ring illumination method to ensure a clear contrast between the Mark feature points and the PCB background. All eight CCD cameras are electrically connected to a synchronous trigger board, which uniformly issues trigger signals to achieve microsecond-level synchronous capture of the eight cameras.

[0078] For example, after the inner layer core board of the PCB is transported to the punching station by the conveyor mechanism and pre-alignment coarse adjustment is completed, the industrial control host sends an image acquisition command to the synchronous trigger board. The synchronous trigger board simultaneously outputs trigger pulse signals to eight CCD cameras. Upon receiving the trigger signals, the eight cameras simultaneously photograph the four corner areas of the upper and lower surfaces of the inner layer core board, respectively acquiring local area images containing each Mark feature point. The field of view of a single camera can be adapted and adjusted according to the size and spacing of the Mark feature points, typically covering a local area of ​​3mm×3mm to 5mm×5mm.

[0079] It should be noted that the eight-channel CCD camera uses a synchronous rather than time-division acquisition method. The technical significance of this is that it avoids the inconsistency error in acquisition time caused by the slight displacement of the board material that may occur during time-division shooting (such as conveyor belt vibration, platform micro-motion, etc.). It ensures that the target data of the four corners of the upper board surface and the target data of the four corners of the lower board surface acquired at the same time are strictly aligned in time, providing original data with consistent time reference for subsequent double-sided layer offset calculation.

[0080] For example, after the eight CCD cameras complete synchronous acquisition, they transmit the target images they have acquired to the industrial control host in the form of digital signals. The industrial control host performs the following preprocessing operations on each image in sequence: (1) Grayscale processing: If the original image acquired by the CCD camera is a color image, the industrial control host first converts it into a grayscale image. Grayscale processing integrates the information of the R, G, and B channels of the color image into single-channel grayscale information, which greatly reduces the amount of data for subsequent processing and improves the computational efficiency while preserving the contour and position information of the Mark feature points in the image.

[0081] (2) Gaussian filtering noise reduction: Gaussian filtering is applied to the grayscale image to eliminate various noises introduced during image acquisition, including electronic noise from the CCD sensor itself, ambient light interference, artifacts caused by minor scratches or dust particles on the PCB board. Gaussian filtering effectively suppresses noise while preventing the edge information of Mark feature points from being overly smoothed by weighting the grayscale value of each pixel in the image with the grayscale values ​​of its neighboring pixels.

[0082] (3) Edge extraction: Edge detection processing is performed on the denoised image. Specifically, the Sobel operator can be used to extract the contour edges of the Mark feature points. Since the Mark feature points are preferably circular markers, their edges have a closed loop structure, and the edge detection algorithm can accurately extract the loop contour. For the extracted edge points, sub-pixel interpolation methods (such as gray-level centroid method or Gaussian fitting) can be further used to improve the positioning accuracy to the sub-pixel level.

[0083] (4) Invalid noise contour removal: In the edge extraction results, there may be invalid contours that are not Mark feature points caused by PCB board texture, slight scratches or residual stains. The industrial control host screens and filters all extracted contours according to the preset geometric parameters of Mark feature points (such as roundness, area range, diameter range, etc.), removes invalid noise contours that do not conform to the preset geometric features, and retains only the valid contours that match the geometric attributes of Mark feature points.

[0084] Further, after image preprocessing, the industrial control host performs center positioning calculations on the retained valid Mark contours. For circular Mark feature points, the centroid of the region enclosed by the contour is calculated as the center position of the Mark feature point, output in pixel coordinates. Subsequently, using the coordinate transformation matrix generated by the pre-completed multi-camera unified world coordinate calibration, the pixel coordinates of each Mark feature point are transformed one by one to the device's unified world coordinate system, obtaining the actual physical coordinates in millimeters. After the above processing, the actual coordinates of the four Mark feature points on the upper plate and the four Mark feature points on the lower plate are finally extracted for subsequent screening and alignment calculations.

[0085] Through the above implementation method, the synchronous acquisition mechanism of eight CCD cameras eliminates the displacement error that may be introduced by time-division acquisition, ensuring strict alignment of the target data on the upper and lower plates in the time dimension. Through a series of preprocessing operations such as grayscale conversion, Gaussian filtering, edge extraction, and invalid contour removal, various noise interferences are effectively filtered out, improving the accuracy and stability of Mark feature point recognition. With the unified world coordinate calibration of multiple cameras, the independent pixel coordinates of each camera are uniformly transformed to the same physical reference, providing original data with a consistent spatial reference for subsequent double-sided layer offset verification and double-sided difference compensation.

[0086] In some implementations, after outputting the compensated attitude corresponding to the current optimal target point as the alignment and correction target, the method further includes: Based on the optimal compensation postures obtained from solving the upper and lower plate surfaces respectively, the independent whole-plate compensation amounts for the upper plate surface and the independent whole-plate compensation amounts for the lower plate surface are generated. Based on the current PCB product specifications, determine the independent precision alignment compensation amount for the upper board surface and the independent precision alignment compensation amount for the lower board surface, which correspond to the product specifications. The independent whole-board compensation amount of the upper board surface is superimposed with the independent precision alignment compensation amount of the upper board surface to generate the final compensation amount of the upper board surface; the independent whole-board compensation amount of the lower board surface is superimposed with the independent precision alignment compensation amount of the lower board surface to generate the final compensation amount of the lower board surface.

[0087] The independent whole-board compensation amount for the upper board refers to the translation and rotation compensation applied to the entire upper board surface of the PCB, including three components: ΔX_U, ΔY_U, and θ_U, which are used to correct the offset and deflection of the entire upper board surface relative to the theoretical reference position. The independent whole-board compensation amount for the lower board refers to the translation and rotation compensation applied to the entire lower board surface of the PCB, including three components: ΔX_D, ΔY_D, and θ_D, which are used to correct the offset and deflection of the entire lower board surface relative to the theoretical reference position.

[0088] It should be noted that the upper and lower surfaces of the PCB undergo independent etching and exposure processes during manufacturing. Due to factors such as uneven distribution of etching solution, exposure alignment deviation, and differences in stress release during pressing, the deformation amplitude and direction of the upper and lower surfaces are often inconsistent. Therefore, the independent whole-board compensation amount of the upper surface and the independent whole-board compensation amount of the lower surface are independent of each other and calculated separately to adapt to the different deformation states of the upper and lower surfaces.

[0089] Product specification information refers to a set of parameters characterizing the characteristics of the current PCB batch, which may include at least one of the following: number of PCB layers, board thickness, core material type, copper thickness, design expansion / contraction coefficient, and customer alignment accuracy level. Different PCB specifications exhibit differences in fixture positioning characteristics, tool wear compensation requirements, and platform dynamic response characteristics during the punching process. These differences introduce additional systematic positioning deviations beyond the overall board compensation amount, requiring correction through "precision alignment compensation."

[0090] The precise alignment compensation amount is a correction amount used to compensate for systematic errors at the product specification level. It differs from the whole-board compensation amount in step S31. The whole-board compensation amount comes from the actual offset detection of the current board material based on the target coordinate data, reflecting the current physical posture deviation of the board material. The precise alignment compensation amount comes from the machine tool error correction parameters obtained by pre-calibration for different product specifications, reflecting the systematic deviation characteristics of the punching equipment when processing this type of board material, including but not limited to: the clamping position deviation caused by different board thicknesses, the target imaging offset caused by different copper thicknesses, and the reference error caused by different material expansion and contraction characteristics.

[0091] For example, the precision alignment compensation amount can be predetermined as follows: During the equipment debugging phase, for each product specification, multiple punching tests are performed using a standard template. The measured positioning deviations after punching are statistically analyzed, and the obtained systematic error is entered into the industrial control host as the precision alignment compensation amount corresponding to that product specification and stored in the product parameter library. When a PCB board of a certain product specification enters the punching process, the industrial control host automatically retrieves the corresponding independent precision alignment compensation amounts for the upper and lower surfaces from the parameter library based on the current product specification information. The independent precision alignment compensation amount and the independent whole-board compensation amount are different types of compensation amounts, and they are stored and retrieved separately.

[0092] It is understandable that the superposition in step S33 refers to vector addition of the overall plate compensation amount and the fine alignment compensation amount in the X and Y directions, respectively, and angular addition in the θ direction. Since both the overall plate compensation amount and the fine alignment compensation amount include translational components in the X and Y directions and rotational components around the Z axis, the final compensation amount after superposition also correspondingly includes translational components in the X and Y directions and rotational components around the Z axis. Specifically, the X-direction component of the final compensation amount for the upper plate surface is the sum of the X-direction translation of the independent overall plate compensation amount for the upper plate surface and the X-direction translation of the fine alignment compensation amount for the upper plate surface; the Y-direction component is calculated similarly, and the θ-direction component is calculated similarly. The calculation method for the final compensation amount for the lower plate surface is the same, but the independent overall plate compensation amount for the lower plate surface and the independent fine alignment compensation amount for the lower plate surface are superimposed. From a functional perspective, the independent whole-board compensation addresses the deviation between the actual placement posture of the PCB board and the theoretical benchmark, belonging to feedback compensation based on real-time target detection. The independent precision alignment compensation addresses the systematic positioning deviation of the punching equipment for different specifications of board materials, belonging to feedforward compensation based on offline calibration. Feedback compensation ensures the correction of individual posture deviations of the board material, while feedforward compensation ensures the correction of system deviations of the equipment. When combined, the final compensation simultaneously takes into account both individual difference correction and system error correction, ensuring that the punching positioning accuracy meets the micron-level processing requirements.

[0093] In some implementations, after the final compensation amount is generated by superposition, it is also necessary to verify whether the final compensation amount of each punch position exceeds the preset global locking boundary. The "global locking boundary" refers to the maximum allowable compensation range preset according to the physical travel limit and process safety requirements of the equipment's three-axis servo attitude adjustment platform. If the final compensation amount of a certain punch position exceeds the locking boundary, the boundary value is used as the actual compensation amount of that punch position to avoid the theoretically calculated compensation amount exceeding the physical execution capability of the equipment.

[0094] Thus, in this embodiment, the independent whole-board compensation amounts for the upper and lower boards are calculated independently based on the target offset data for each board. This accurately adapts to the differential deformations of the upper and lower boards caused by previous processes such as etching and lamination, avoiding the crude approach of using the same set of compensation amounts for both boards in single-sided imaging schemes. Simultaneously, it introduces independent precision alignment compensation based on product specifications, setting compensation amounts for different PCB board specifications. This effectively compensates for systemic positioning deviations caused by factors such as board thickness, copper thickness, and fixture characteristics, improving... The equipment's adaptability to products of different specifications has been improved; independent whole-plate compensation and independent precision alignment compensation are layered independently and do not interfere with each other. The whole-plate compensation based on real-time target detection solves the individual posture deviation of each plate, while the precision alignment compensation based on offline calibration solves the systemic deviation of the equipment for different specifications of plates. The two are superimposed to simultaneously correct the positioning errors from two different sources, forming a complete error compensation chain. This takes into account the individual differences of each plate in the mass production line and the system adaptation requirements of the equipment for different specifications of products, ensuring that the punching positioning accuracy meets the micron-level processing requirements.

[0095] In some implementations, a circular screening domain is constructed using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates as the screening radius, including at least one of the following: Calculate the offset distance between the actual coordinates of each Mark feature point and the corresponding theoretical reference coordinates. If any offset distance does not exceed the preset warning threshold, then use the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates relative to the theoretical reference coordinates in the current posture as the screening radius to construct a circular screening area. The lateral and longitudinal offset differences between the actual coordinates of the same Mark feature points on the upper and lower plates are calculated respectively. If the lateral or longitudinal offset difference does not exceed the preset i-deformation threshold, the theoretical reference coordinates are used as the screening center, and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates is used as the screening radius to construct a circular screening domain.

[0096] Among them, single-point offset screening refers to: calculating the offset distance between the actual coordinates of each Mark feature point and the corresponding theoretical reference coordinates. If any of the offset distances exceeds the preset warning threshold, it is determined that the current PCB inner layer core board size is out of tolerance, the subsequent steps are terminated and the diversion and material arrangement are performed.

[0097] Specifically, in step S1, the industrial control host has obtained the actual coordinates (x, y, x) of the four Mark feature points on the upper panel. u1 ,y u1 ), (x u2 ,y u2 ), (xu3 ,y u3 ), (x u4 ,y u4 ) and the corresponding theoretical reference coordinates (x 0U1 ,y 0U1 ), (x 0U2 ,y 0U2 ), (x 0U3 ,y 0U3 ), (x 0U4 ,y 0U4 For the i-th Mark feature point on the upper panel, the industrial control host calculates its offset distance as follows: calculate the difference between the actual coordinates and the theoretical reference coordinates of the point in the X and Y directions respectively, and then take the square root of the sum of the squares of the two differences to obtain the offset straight-line distance of the point. Similarly, for the i-th Mark feature point on the lower panel, the industrial control host calculates its offset straight-line distance in the same way.

[0098] The industrial control host compares each of the eight offset distances calculated above with a preset warning threshold. The preset warning threshold is a pre-set critical value used to determine whether a single-point offset exceeds the limit. Its value is greater than the preset accuracy threshold in step S4, and is usually several times the accuracy threshold (for example, when the accuracy threshold is 0.02mm, the warning threshold can be set to 0.05mm to 0.10mm). If the offset distance of any Mark feature point exceeds the preset warning threshold, it indicates that there is a serious positional deviation in a corner of the board. This deviation is far beyond the range that the subsequent dynamic screening domain convergence screening algorithm can compensate for. The industrial control host then determines that the current PCB inner layer core board size is out of tolerance and belongs to an unrepairable defective board. It then terminates all subsequent alignment and punching steps and links the diversion mechanism to discharge the board from the main conveying channel.

[0099] For example, double-sided deformation screening refers to: calculating the lateral offset difference and the longitudinal offset difference between the actual coordinates of the same source Mark feature points on the upper and lower surfaces respectively; if the lateral offset difference or the longitudinal offset difference exceeds the preset deformation threshold, it is determined that the double-sided deformation of the current PCB inner layer core board is unbalanced, the subsequent steps are terminated and the diversion and material arrangement are performed.

[0100] Specifically, theoretically, the source Mark feature points on the upper and lower surfaces of the PCB inner layer core board should have completely overlapping coordinate positions, meaning that the theoretical reference coordinates of the i-th Mark feature point on the upper surface and the i-th Mark feature point on the lower surface are numerically identical. However, in actual production, due to multiple factors such as uneven etching solution spraying, differences in copper layer thickness, and stress release during lamination, the deformation amplitude of the upper and lower surfaces of the same board often differs, causing the actual coordinates of the source Mark feature points to no longer coincide in space.

[0101] Specifically, in step S1, the industrial control host has obtained the actual coordinates of the four Mark feature points on the upper panel and the four Mark feature points on the lower panel, respectively. For the i-th pair of Mark feature points from the same source, the industrial control host calculates their offset difference as follows: Lateral offset difference:

[0102] That is, the X coordinate of the i-th Mark feature point on the upper plate minus the X coordinate of the i-th Mark feature point on the lower plate; the longitudinal offset difference is the Y coordinate of the i-th Mark feature point on the upper plate minus the Y coordinate of the i-th Mark feature point on the lower plate.

[0103] The industrial control host compares each of the eight offset differences (four lateral offset differences + four longitudinal offset differences) calculated above with a preset deformation threshold. The preset deformation threshold is a pre-set critical value used to determine whether the double-sided deformation is unbalanced. Its specific value can be entered by staff through a human-machine interface during the process parameter configuration stage, based on the board specifications, customer order requirements, and equipment capabilities. If the lateral or longitudinal offset difference of any pair of identical Mark feature points exceeds the preset deformation threshold, it indicates that the deformation difference between the upper and lower surfaces of the board has exceeded the acceptable range. That is, the deviation between the upper and lower surface graphic offsets is too large, constituting a layer misalignment risk. The industrial control host then determines that the current PCB inner layer core board has a double-sided deformation imbalance, belonging to an unrepairable defective board, and immediately terminates all subsequent alignment and punching steps, and activates the diversion mechanism to discharge the board.

[0104] It should be noted that if the above single-point offset screening and double-sided deformation screening are both passed (i.e., the offset distance of all single points does not exceed the preset warning threshold, and the lateral offset difference and longitudinal offset difference of all targets of the same origin do not exceed the preset deformation threshold), it indicates that the current PCB inner layer core board is a good quality board with qualified dimensions and basically consistent deformation of the upper and lower board surfaces. The industrial control host continues to execute the subsequent steps S2 (constructing a circular screening area) and the screening and alignment process of steps S3 to S4.

[0105] In this embodiment, before activating the core screening algorithm, complete target data from both upper and lower board surfaces are acquired through simultaneous dual-sided acquisition using eight-channel CCDs, enabling a dual-layer pre-judgment logic that traditional 2CCD / 4CCD single-sided imaging equipment cannot achieve. Specifically, single-point offset screening intercepts boards with severe dimensional deviations before screening and alignment, avoiding ineffective domain shrinkage iteration calculations and punching processes. Dual-sided deformation screening identifies boards with excessively large deformation differences between the upper and lower board surfaces, posing a risk of layer misalignment, and removes them before the punching process, preventing them from flowing into subsequent lamination processes and causing the entire board to be scrapped. Through this multi-dimensional pre-judgment defect screening mechanism, this embodiment effectively reduces the ineffective computational load of PCB punching and alignment equipment and the ineffective processing losses of the punching process, reducing the scrap cost of high-end multilayer PCBs due to layer misalignment from the source.

[0106] In some implementations, after outputting the compensated attitude corresponding to the current optimal target point as the alignment and correction target, the method further includes: The actual coordinates, cumulative offset, optimal target point, compensation posture, and quality judgment results during the alignment process are archived. Layer offset feedback data is obtained through bidirectional data interaction with the backend X-Ray detection equipment. The preset accuracy threshold and / or the screening radius are adaptively adjusted based on the layer offset feedback data.

[0107] After the punching operation is completed, the industrial control host automatically archives and stores all the process data generated during the alignment and punching of the inner core boards of this batch of PCBs, including but not limited to the following data types: (1) Target coordinate data: The actual coordinates and corresponding theoretical reference coordinates of the four Mark feature points on the upper and lower surfaces obtained in step S1; (2) Total offset accumulation: The total offset accumulation of four points on a single surface corresponding to each candidate point calculated in step S3, and the total offset accumulation of the finally selected optimal target point; (3) Optimal target point and compensation attitude: the coordinates of the optimal target point determined in step S3, and the compensation attitude (including the compensation amount in the X direction, Y direction and θ rotation direction) of the alignment and correction target output in step S51 or S52. (4) Screening parameters: the coordinates of the screening center, screening radius, number of shrinkage iterations, and coordinates of the optimal target point in each round of screening iterations; (5) Compensation coefficient: including the point-level fine adjustment amount of each punch position generated during the double-sided differential compensation process, and the independent whole-plate compensation amount of the upper plate surface and the independent whole-plate compensation amount of the lower plate surface formed by superimposing the point-level fine adjustment amount; superimposing the independent whole-plate compensation amount of the upper plate surface with the independent fine alignment compensation amount of the upper plate surface to generate the final compensation amount of the upper plate surface; superimposing the independent whole-plate compensation amount of the lower plate surface with the independent fine alignment compensation amount of the lower plate surface to generate the final compensation amount of the lower plate surface; (6) Quality judgment results: the judgment results of the pre-defect screening (single-point offset screening and double-sided deformation screening), the accuracy judgment results of step S4, and the qualified / unqualified mark of the plate after the final punching is completed.

[0108] The aforementioned comprehensive process data is indexed according to the batch number and sheet number of the sheet material, and stored in the local database of the industrial control host or uploaded to the factory's MES (Manufacturing Execution System) via Ethernet. The data archive adopts a structured storage format to facilitate subsequent retrieval, statistical analysis, and trend tracking.

[0109] For example, after the punching process is completed, the inner layer core board of the PCB enters the subsequent lamination process. After lamination, the laminated multilayer board needs to be inspected for layer misalignment to verify whether the alignment accuracy between the core boards of each layer meets the design requirements. This layer misalignment inspection is performed by a back-end X-ray inspection device.

[0110] For example, X-ray inspection equipment utilizes X-ray imaging technology to penetrate multilayer PCB boards and acquire projected images of targets in each layer (including Mark feature points on each inner core board and concentric alignment rings formed after lamination). By comparing and analyzing the projected positions of the targets in each layer, the X-ray inspection equipment can accurately calculate the layer offset between each layer.

[0111] For example, a bidirectional data link is established between the punching alignment device and the back-end X-Ray inspection device via an Ethernet communication unit. Specifically, this includes: (1) Forward data transmission: After completing the punching operation, the punching alignment equipment sends the following data of the current batch of plates to the X-Ray detection equipment: the batch number and serial number of each plate, the actual coordinates and theoretical reference coordinates of each Mark feature point obtained in step S1, the compensation posture corresponding to the alignment correction target output in step S51 or S52, and the final compensation amount of double-sided differentiation generated after outputting the compensation posture corresponding to the current optimal target point as the alignment correction target. After receiving the above data, the X-Ray detection equipment can use it as a reference benchmark for layer deviation detection. For example, it can compare the target positions of each layer detected by X-Ray with the theoretical reference coordinates and compensation postures provided by the punching equipment to evaluate the actual effect of punching alignment and the contribution relationship of layer deviation.

[0112] (2) Backward data feedback: After the X-Ray inspection equipment completes the layer deviation detection, it feeds back the detection results to the industrial control host of the punching alignment equipment. The feedback data includes: the actual layer deviation of each plate (including the layer deviation values ​​in the X and Y directions), the judgment result of whether the layer deviation is qualified, and the number and deviation value of the plate with excessive layer deviation.

[0113] Through the aforementioned two-way data interaction, a complete data closed loop is formed between the punching alignment equipment and the X-Ray inspection equipment. That is, the alignment parameters of the punching equipment are output to the X-Ray equipment as an inspection reference, and the inspection results of the X-Ray equipment are fed back to the punching equipment as a basis for parameter optimization.

[0114] Furthermore, the industrial control host adaptively adjusts the preset accuracy threshold used in step S4 and / or the screening radius initially constructed in step S2 based on the layer offset data fed back by the X-Ray detection equipment.

[0115] Specific adaptive adjustment methods include: (1) Threshold adjustment based on layer deviation statistics: The industrial control host performs statistical analysis on the layer deviation data of each board material fed back by X-Ray over a period of time (e.g., the past 24 hours or the past 100 batches). If the statistical results show that the layer deviation is generally large and close to the upper limit of the preset layer deviation acceptable tolerance, it indicates that there is still room for improvement in the current punching alignment accuracy. The industrial control host will then appropriately tighten the preset accuracy threshold (e.g., from 0.02mm to 0.015mm) to make the punching alignment of subsequent batches more stringent, thereby reducing the risk of layer deviation. Conversely, if the statistical results show that the layer deviation is generally much smaller than the acceptable tolerance and the punching alignment takes a long time, the industrial control host can appropriately relax the preset accuracy threshold (e.g., from 0.02mm to 0.025mm) to improve the alignment efficiency while ensuring the layer deviation is acceptable.

[0116] (2) Screening radius adjustment based on layer offset distribution characteristics: The industrial control host analyzes the distribution characteristics of the layer offset data of each board material fed back by X-Ray. If a clear directional trend of layer offset is found (for example, the layer offset of most boards is mainly concentrated in the positive X direction), it indicates that there is a systematic unidirectional deformation deviation in the upstream process (such as etching or pressing). The industrial control host can adaptively adjust the value of the initial screening radius according to this trend. For example, a directional offset is superimposed on the screening radius so that the center of the initial screening domain is no longer located at the theoretical reference coordinate, but is moderately offset in the opposite direction of the systematic deviation, so as to cover the area that is more likely to contain the optimal solution in the first round of screening and reduce the number of domain shrinkage iterations.

[0117] (3) Comprehensive parameter tuning based on historical yield data: The industrial control host integrates the yield data of the punching and alignment process with the layer deviation pass rate data of X-Ray detection to establish a correlation model between process parameters and product quality. When it is found that the layer deviation pass rate corresponding to a certain parameter combination (such as a combination of a certain preset accuracy threshold and a certain initial screening radius) is significantly higher than that of other combinations, the industrial control host automatically applies the parameter combination as the preferred solution to subsequent batches.

[0118] The aforementioned adaptive adjustments can be performed in real time after each batch of production is completed, or in batches according to a set cycle (e.g., every 100 batches). The adjusted new parameters are automatically applied to the punching and alignment process of subsequent batches without manual intervention.

[0119] In this embodiment, a complete data closed loop is constructed, from punching alignment to layer deviation detection and then to parameter optimization. Automatic archiving of full-dimensional process data provides a data foundation for quality traceability and process analysis; bidirectional data interaction between the punching equipment and X-ray inspection equipment enables layer deviation detection results to guide the optimization of punching alignment parameters; and an adaptive threshold and screening radius adjustment mechanism based on layer deviation feedback data allows process parameters to be autonomously iteratively optimized according to actual fluctuations in upstream processes, reducing reliance on operator experience and facilitating continuous improvement in punching alignment accuracy and product yield.

[0120] Based on the same inventive concept as the foregoing embodiments, this application provides a PCB punching and alignment device, such as... Figure 2 As shown, the device includes: a processor 310 and a memory 311 storing a computer program; wherein, Figure 2 The processor 310 shown in the diagram does not indicate that there is only one processor 310, but only indicates the positional relationship of the processor 310 relative to other devices. In practical applications, there can be one or more processors 310; similarly, Figure 2 The memory 311 illustrated in the diagram has the same meaning, that is, it is only used to indicate the positional relationship of memory 311 relative to other devices. In practical applications, the number of memories 311 can be one or more. When the processor 310 runs the computer program, the medical interpretation processing method applied to the above-mentioned device is implemented. The device may also include: at least one network interface 312. The various components in the device are coupled together through a bus system 313. It is understood that the bus system 313 is used to realize the connection and communication between these components. In addition to a data bus, the bus system 313 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in Figure 2 The general designated all buses as Bus System 313.

[0121] The memory 311 can be volatile memory or non-volatile memory, or both. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferromagnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM); magnetic surface memory can be disk storage or magnetic tape storage. Volatile memory can be random access memory (RAM), used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), SyncLink Dynamic Random Access Memory (SLDRAM), and Direct Rambus Random Access Memory (DRRAM).The memory 311 described in the embodiments of this application is intended to include, but is not limited to, these and any other suitable types of memory.

[0122] The memory 311 in this embodiment is used to store various types of data to support the operation of the device. Examples of this data include: any computer programs used to operate on the device, such as operating systems and applications; contact data; phonebook data; messages; pictures; videos, etc. The operating system includes various system programs, such as the framework layer, core library layer, driver layer, etc., used to implement various basic services and handle hardware-based tasks. Applications can include various applications, such as media players, browsers, etc., used to implement various application services. Here, the program implementing the method of this embodiment can be included in the application.

[0123] Based on the same inventive concept as the foregoing embodiments, this embodiment also provides a computer-readable storage medium storing a computer program. The computer-readable storage medium can be a magnetic random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM), etc.; it can also be various devices including one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc. When the computer program stored in the computer-readable storage medium is executed by a processor, it implements the above-described medical interpretation method. For the specific steps implemented when the computer program is executed by the processor, please refer to [link to relevant documentation]. Figure 1 The description of the illustrated embodiments will not be repeated here.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0126] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for aligning punched holes in the inner layer core board of a PCB, characterized in that, Includes the following steps: S1: Obtain the actual coordinates and corresponding theoretical reference coordinates of four Mark feature points on one side of the inner core board of the PCB. S2: Using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates under the current posture relative to the theoretical reference coordinates as the screening radius, a circular screening domain is constructed; the four corner points of the inscribed square parallel to the axis of the circular screening domain are taken as candidate points, and each candidate point represents a candidate alignment posture. S3: Using each candidate point as the compensation posture of the current PCB inner layer core board, calculate the sum of the offset straight-line distances of the actual coordinates of the four Mark feature points on a single side under the compensation posture relative to their respective theoretical reference coordinates, and use it as the cumulative offset of the four points on a single side corresponding to each candidate point; take the candidate point corresponding to the minimum cumulative offset as the optimal target point in the current screening domain. S4: Determine whether the distance between the theoretical reference coordinates and the optimal target point is less than a preset accuracy threshold; S51: If it is less than, then the compensation posture corresponding to the current optimal target point shall be used as the alignment and correction target; S52: If not less than, then take the length of the line connecting the theoretical reference coordinates and the current optimal target point as the diameter of the new circular screening domain, take the midpoint of the line as the new screening center, take the four corner points of the axis-parallel inscribed square of the new screening domain as the new round of candidate points, determine the minimum new offset cumulative value of each new round of candidate points, repeat step S4 until the distance between the current optimal target point and the theoretical reference coordinates is less than the preset accuracy threshold, and output the compensation posture corresponding to the current optimal target point as the alignment correction target; or, when the distance between the optimal target points obtained by two adjacent iterations is less than the minimum executable step of the three-axis servo attitude adjustment platform, output the compensation posture corresponding to the current optimal target point as the alignment correction target.

2. The method according to claim 1, characterized in that, The method for calculating the cumulative total of four-point offsets on a single surface includes: Calculate the Euclidean distance between the actual coordinates of the four Mark feature points on a single surface and their corresponding theoretical reference coordinates. Sum the four Euclidean distance values ​​to obtain the cumulative value of the four-point offset on a single surface under the compensated posture.

3. The method according to claim 1, characterized in that, When the optimal target point distance obtained from two adjacent iterations is less than the minimum executable step size of the three-axis servo attitude adjustment platform, the compensation attitude corresponding to the current optimal target point is output as the alignment correction target, including: If the distance between the optimal target points obtained from two adjacent iterations in a single attitude is less than the minimum executable step of the three-axis servo attitude adjustment platform, and the distance between the theoretical reference coordinates and the optimal target point still does not meet the requirement of being less than the preset accuracy threshold, then the three-axis servo attitude adjustment platform is controlled to fine-tune the overall attitude of the inner core board of the PCB, and step S1 is re-executed in the adjusted attitude until the optimal compensation posture corresponding to the distance between the theoretical reference coordinates and the optimal target point being less than the preset accuracy threshold is selected.

4. The method according to claim 3, characterized in that, The method further includes: If the number of times the three-axis servo attitude adjustment platform adjusts the overall attitude of the PCB inner core board exceeds the preset number, and the distance between the theoretical reference coordinate and the optimal target point still does not meet the preset accuracy threshold, then an out-of-tolerance alarm is triggered and the diversion mechanism is linked to discharge the PCB inner core board.

5. The method according to claim 1, characterized in that, The process of obtaining the actual coordinates and corresponding theoretical reference coordinates of four Mark feature points on one side of the PCB inner layer core board includes: Eight CCD cameras deployed on the upper and lower sides of the PCB inner core board synchronously acquire target images of the upper and lower surfaces of the PCB inner core board. After image preprocessing, the actual coordinates of four Mark feature points on each of the upper and lower surfaces are extracted.

6. The method according to claim 5, characterized in that, After outputting the compensated attitude corresponding to the current optimal target point as the alignment and correction target, the method further includes: Based on the optimal compensation postures obtained from solving the upper and lower plate surfaces respectively, the independent whole-plate compensation amounts for the upper plate surface and the independent whole-plate compensation amounts for the lower plate surface are generated. Based on the current PCB product specifications, determine the independent precision alignment compensation amount for the upper board surface and the independent precision alignment compensation amount for the lower board surface corresponding to the product specifications. The independent whole-board compensation amount of the upper board surface is superimposed with the independent precision alignment compensation amount of the upper board surface to generate the final compensation amount of the upper board surface; the whole-board compensation amount of the lower board surface is superimposed with the independent precision alignment compensation amount of the lower board surface to generate the final compensation amount of the lower board surface.

7. The method according to claim 5, characterized in that, The construction of a circular screening domain, using the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates as the screening radius, includes at least one of the following: Calculate the offset distance between the actual coordinates of each Mark feature point and the corresponding theoretical reference coordinates. If any offset distance does not exceed the preset warning threshold, then use the theoretical reference coordinates as the screening center and the offset distance of the actual coordinates relative to the theoretical reference coordinates in the current posture as the screening radius to construct a circular screening area. Calculate the lateral and longitudinal offset differences between the actual coordinates of the original Mark feature points on the upper and lower surfaces respectively. If the lateral or longitudinal offset difference does not exceed a preset value... i If the deformation threshold is set, then the theoretical reference coordinates are used as the screening center, and the offset distance of the actual coordinates in the current posture relative to the theoretical reference coordinates is used as the screening radius to construct a circular screening domain.

8. The method according to claim 5, characterized in that, After outputting the compensated attitude corresponding to the current optimal target point as the alignment and correction target, the method further includes: The actual coordinates, cumulative offset, optimal target point, compensation posture, and quality judgment results during the alignment process are archived. Layer offset feedback data is obtained through bidirectional data interaction with the backend X-Ray detection equipment. The preset accuracy threshold and / or the screening radius are adaptively adjusted based on the layer offset feedback data.

9. A PCB punching and alignment device, characterized in that, include: A processor and a memory storing a computer program, wherein when the processor runs the computer program, the steps of the PCB inner layer core board punching and alignment method as described in any one of claims 1 to 8 are implemented.

10. A machine storage medium, characterized in that, The device contains a computer program that, when executed by a processor, implements the steps of the PCB inner layer core board punching and alignment method according to any one of claims 1 to 8.

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