Automatic punching control method and system for flexible circuit board

Abstract

The invention relates to the technical field of circuit board processing, in particular to an automatic punching control method and system for a flexible circuit board. According to the method, an initial positioning point is determined through edge saliency analysis in preliminary analysis image data, association between a physical FPC and ideal design coordinates is established, a more accurate position of an initial hole site is determined, deformation deviation is quantified for a second hole site in combination with the initial positioning point and the initial hole site, and through the influence proportion of a global error and a local error, the position of the second hole site is determined. And carrying out weight balance correction to obtain an error correction value to carry out dynamic compensation correction on the hole site. According to the method, the overall and local deformation conditions are quantified, error correction is carried out from direction and distance equilibrium deviation weights, tracking dynamic correction of continuous punching is carried out, batch error accumulation is reduced, and the accuracy of the punching position is improved in real time.

Description

Technical Field

[0001] This invention relates to the field of circuit board processing technology, specifically to an automatic control method and system for drilling holes in flexible circuit boards. Background Technology

[0002] Flexible printed circuit boards (FPCs) have become an indispensable core component in modern electronic devices due to their excellent flexibility, foldability, and high integration. However, the physical characteristics of FPC substrates—softness, easy deformation, and extremely high alignment precision requirements—pose significant challenges to their precision manufacturing processes, with the fabrication of microvias being particularly critical. These microvias are fundamental for achieving interlayer electrical interconnection and component mounting, and their fabrication quality directly determines the reliability of the circuit, signal integrity, and the yield of the final product.

[0003] Existing technologies mainly rely on semi-automatic or fully automatic CNC drilling systems that combine mechanical positioning with optical alignment. A typical workflow is as follows: First, offline programming software (such as CAM) generates coordinate files for the drilling positions, such as Gerber files, based on the circuit design diagram. Then, the operator fixes the FPC board onto the carrier plate and manually or with the aid of a low-precision camera locates the reference target (Mark point) on the board for initial alignment. The system drives the X and Y axis servo motors for positioning based on the input coordinate file, and finally, the spindle motor drives the drill bit to perform the drilling operation.

[0004] However, because FPC material is soft, it is easily stretched, deformed or wrinkled due to stress, temperature and humidity changes during fixing and processing. This causes the pre-programmed coordinates to deviate from the actual position of the material, resulting in batch alignment differences. The system lacks the ability to track and compensate in real time during operation. Summary of the Invention

[0005] To address the technical problems in the prior art, the present invention aims to provide an automatic drilling control method and system for flexible printed circuit boards, the specific technical solution of which is as follows: The first aspect of this application provides an automatic control method for drilling holes in a flexible printed circuit board, the method comprising: Obtain Gerber files and image data of flexible circuit boards; The initial positioning point is determined based on the saliency of features on the edge line in the image data; the initial hole position is obtained by drilling based on the initial positioning point and the hole position information in the Gerber file; the expected coordinates of the second hole position are determined based on the initial hole position. Based on the expected theoretical deviations between the second hole position and the initial hole position in terms of distance and direction, the local errors in distance and direction are determined respectively; based on the expected theoretical deviations between the second hole position and each initial positioning point in terms of distance and direction, the global errors in distance and direction are determined respectively; for each distance and direction, the error correction value of the second hole position is obtained by correcting the error magnitude through the deviation ratio between the global error and the local error. The expected coordinates of the second hole are corrected by using the error correction value, and the position of each hole to be drilled is corrected by using the error correction values ​​of all previous holes.

[0006] Furthermore, the method for obtaining the initial positioning point includes: Obtain the edge points of the flexible circuit board boundary in the image data, and calculate the pixel value difference between every two consecutive edge points; use the mean of the difference values ​​corresponding to each edge point as the difference degree of the edge point; Based on the degree of difference between each edge point and other edge points on the boundary, obtain the significance index of each edge point; The edge points are sorted from largest to smallest according to their significance index to obtain a significance sequence; the first three edge points in the significance sequence are used as initial positioning points; the initial positioning points are not continuous.

[0007] Furthermore, the method for obtaining the significance index includes: For any edge point, calculate the difference between the edge point and each edge point within a preset local range, and then use the sum of all differences as the neighborhood difference of the edge point. Calculate the ratio of the difference degree of the edge point to the mean difference degree of all edge points to obtain the difference significance of the edge point; By combining the neighborhood dissimilarity and differential significance of the edge point, the significance index of the edge point is obtained.

[0008] Furthermore, the method for obtaining the local error includes: Calculate the distance between the predicted coordinates of the second hole and the initial hole, which is taken as the actual predicted distance between the second hole and the initial hole; obtain the distance between the theoretical coordinates of the initial hole and the second hole based on the Gerber file, which is taken as the theoretical distance; calculate the difference between the actual predicted distance and the theoretical distance to obtain the local error of the second hole in terms of distance. Calculate the orientation angle of the second hole position relative to the initial hole position in the expected coordinates, as the actual expected orientation angle; obtain the orientation angle of the second hole position relative to the initial hole position in the theoretical coordinates based on the Gerber file, as the theoretical orientation angle; calculate the difference between the actual expected orientation angle and the theoretical orientation angle to obtain the local error of the second hole position in the direction.

[0009] Furthermore, the method for obtaining the global error includes: For any initial positioning point, calculate the distance between the predicted coordinates of the second hole and the initial positioning point, and use it as the predicted positioning distance between the second hole and the initial positioning point; obtain the distance between the theoretical coordinates of the initial positioning point and the second hole based on the Gerber file, and use it as the theoretical positioning distance; calculate the difference between the predicted positioning distance and the theoretical positioning distance to obtain the positioning error in distance between the second hole and the initial positioning point; Calculate the orientation angle of the second hole position relative to the initial positioning point, and use it as the positioning orientation angle; obtain the orientation angle of the second hole position relative to the initial positioning point in the theoretical coordinates based on the Gerber file, and use it as the positioning theoretical orientation angle; calculate the difference between the positioning orientation angle and the positioning theoretical orientation angle to obtain the positioning error between the second hole position and the initial positioning point in the direction. The average of the distance errors between the second hole and all initial positioning points is taken as the global error of the second hole in terms of distance; the average of the orientation angle errors between the second hole and all initial positioning points is taken as the global error of the second hole in terms of orientation.

[0010] Furthermore, the method for obtaining the error correction value includes: In terms of distance, the mean of the local error and the global error of the second hole position is used as the error mean; the ratio of the global error to the local error is normalized to obtain the correction weight; the product of the correction weight and the error mean is used as the error correction value of the second hole position in terms of distance. In terms of direction, the average of the local and global errors of the second hole position is used as the error mean; the ratio of the global error to the local error is normalized to obtain the correction weight; the product of the correction weight and the error mean is used as the error correction value of the second hole position in the direction.

[0011] Further, the step of correcting the predicted coordinates of the second hole position by using the error correction value includes: The expected coordinates of the second hole are compared with the theoretical coordinates in the Gerber file. The direction angle is deflected by the error correction value, and the distance is corrected based on the distance error correction value to obtain the corrected coordinates of the second hole and then the hole is drilled.

[0012] Further, the step of correcting the coordinate position of each hole to be drilled based on the error correction values ​​of all previous holes includes: Arrange the holes in the drilling order to obtain the drilling sequence; In terms of distance, the error correction values ​​of all holes before the hole to be punched are weighted, averaged, and normalized using the sequence number in the punching sequence as the weight, to obtain the correction control coefficient of the hole to be punched in terms of distance; the mean of the local error and the global error of the hole to be punched in terms of distance is taken as the distance error of the hole to be punched; the product of the distance error and the correction control coefficient is taken as the error correction value of the hole to be punched in terms of distance. In terms of direction, the error correction values ​​of all holes before the hole to be drilled are weighted, averaged, and normalized using the sequence number in the drilling sequence as the weight, to obtain the distance correction control coefficient of the hole to be drilled; the mean of the local error and global error of the hole to be drilled is taken as the direction error of the hole to be drilled; the product of the direction error and the correction control coefficient is taken as the error correction value of the hole to be drilled in the direction. The expected coordinates of the hole to be drilled are corrected using the error correction value, and then the hole is drilled.

[0013] Furthermore, the method for obtaining the initial hole position includes: Based on the theoretical coordinates and hole position information of the initial hole position in the Gerber file, the drilling position on the flexible circuit board is determined by the three-point positioning method through the initial positioning point, and the hole is drilled at the drilling position to obtain the initial hole position.

[0014] Secondly, this application provides an automatic drilling control system for flexible printed circuit boards, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the automatic drilling control method for flexible printed circuit boards described above.

[0015] Thirdly, this application provides a computer device including a memory and a processor. The memory is used to store computer program code, and the processor is used to call and run the computer program code from the memory to perform the method as described in the first aspect of this application or any embodiment of the first aspect.

[0016] Fourthly, this application provides a computer program product comprising computer program code, which, when executed, performs the method as described in the first aspect of this application or any embodiment thereof.

[0017] Fifthly, this application provides a computer-readable storage medium that stores computer program code, which, when executed, performs the method as described in the first aspect of this application or any embodiment thereof.

[0018] The present invention has the following beneficial effects: This invention determines the initial positioning point through edge saliency analysis of image data, establishes a correlation between the physical FPC and the ideal design coordinates, and determines a more accurate initial hole position. Further, for the second hole position, it quantifies the deformation deviation between the initial positioning point and the initial hole position, and performs weighted balancing correction by calculating dual-reference errors, considering the different weights of deformation in the global and local contexts. This makes the error correction for hole positioning more accurate and reliable. Finally, the accumulated error correction value is used to dynamically compensate and correct the holes to be drilled subsequently, improving drilling accuracy. This invention quantifies the overall and local deformation, balances the deviation weights in direction and distance for error correction, and performs dynamic correction for continuous drilling, reducing batch error accumulation and improving the accuracy of drilling position in real time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A flowchart illustrating an automatic drilling control method for a flexible circuit board according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a computer device structure provided in one embodiment of the present invention. Detailed Implementation

[0021] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an automatic drilling control method and system for flexible circuit boards proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] The following description, in conjunction with the accompanying drawings, details the specific scheme of the automatic drilling control method and system for flexible circuit boards provided by the present invention.

[0024] Flexible printed circuit boards (FPCs) are commonly used in high-density interconnect (HDI) applications, where vias are the sole pathway for connecting electrical signals across multiple layers of circuitry. Even the slightest deviation in via placement can cause misalignment between layers, leading to fatal defects such as open circuits, short circuits, or impedance mismatches, ultimately rendering the entire module unusable. Unlike rigid PCBs, the via walls of FPCs must withstand the stress of repeated bending. Therefore, extremely high quality requirements are placed on the vias, such as burr-free surfaces and smooth inner walls. This must be achieved through precise control of the drill bit's rotation speed, feed rate, and tool change frequency to prevent material tearing, carbonization, or melting, thereby ensuring the integrity of the via wall structure and its long-term durability under dynamic bending.

[0025] During the fabrication of flexible circuit boards, the flexible substrate (such as polyimide PI) is soft and prone to elastic deformation. Stress, temperature and humidity changes, and adhesive shrinkage during processing can easily cause the board to expand, warp, or wrinkle. Furthermore, the flexible surface makes it difficult to control the adhesion and uniformity of photoresist or dry film, which can easily lead to poor coverage, peeling, or lateral etching, resulting in linewidth accuracy deviations, broken lines, or short circuits.

[0026] Therefore, in order to more accurately drill holes in flexible circuit boards, this application provides an automatic control method for drilling holes in flexible circuit boards through dynamic compensation and automatic control. Please refer to [link to relevant documentation]. Figure 1 The diagram illustrates an automatic drilling control method for flexible printed circuit boards according to an embodiment of the present invention. The method includes the following steps: S1: Obtain Gerber files and image data of the flexible circuit board.

[0027] Due to their bendable nature, flexible circuit boards are prone to deformation and displacement during processing, thus requiring more precise hole positioning compared to rigid PCBs. In this embodiment of the invention, design files, such as Gerber files, are acquired, including precise theoretical coordinates for hole positioning, hole diameter information, and layer information, providing a processing benchmark for actual operations. Simultaneously, a high-resolution CCS camera is installed next to the drilling machine spindle to photograph and capture alignment marks, enabling real-time image analysis and calculation, providing a data analysis basis for subsequent dynamic compensation.

[0028] The entire flexible circuit board substrate is captured by a camera, and image data is obtained through image preprocessing. Image preprocessing may specifically include image grayscale conversion and image denoising, etc. Image preprocessing is a well-known technique in the field and is not limited thereto.

[0029] S2: Determine the initial positioning point based on the salience of features on the edge line in the image data; drill holes to obtain the initial hole positions based on the initial positioning point and the hole position information in the Gerber file; determine the expected coordinates of the second hole position based on the initial hole positions.

[0030] Considering the stretching, rotation, and offset that may occur during the processing of flexible printed circuit boards (FPCs), the physical edge of the FPC is first theoretically located by selecting positioning points. This allows for a more accurate mapping between the position coordinates in the Gerber design file and the actual position. Then, the initial hole positions are determined using the three-point positioning method for drilling.

[0031] In this embodiment of the invention, the method for obtaining the initial positioning point includes: The edge points of the flexible circuit board boundary in the image data are obtained, and the pixel value difference between every two consecutive edge points is calculated. The mean of the difference values ​​corresponding to each edge point is used as the difference degree of the edge point. When the first-order difference between adjacent pixels is large, the pixels are more prominent as inflection points or feature points on the edge, and are easier to locate accurately due to their prominent features on the edge.

[0032] Based on the significance of the difference between each edge point and other edge points on the boundary, a significance index for each edge point is obtained. In this embodiment of the invention, for any edge point, after calculating the difference between the edge point and each edge point within a preset local range, the sum of all differences is used as the neighborhood difference of the edge point. By calculating the difference between the edge point and each other edge point in the local range, the prominence of the difference within the local range is reflected. The preset local range is set to a size encompassing seven edge points centered on the edge point. The specific setting can be adjusted by the implementer according to the specific implementation scenario and is not limited here.

[0033] Furthermore, the ratio of the differential degree of the edge point to the mean differential degree of all edge points is calculated to obtain the differential significance of the edge point. Through relative analysis with the overall differential situation, the prominence of the differential situation within the overall range is reflected. Finally, combining the neighborhood variability and differential significance of the edge point, a significance index for the edge point is obtained. In this embodiment of the invention, the sum of the neighborhood variability and differential significance is used as the significance index of the edge point. The larger the significance index, the stronger the characterization ability of the edge point.

[0034] The edge points are sorted from largest to smallest according to their significance index to obtain a significance sequence. The first three edge points in the significance sequence are used as initial positioning points. Taking three positioning points facilitates accurate positioning, and it is necessary to ensure that the initial positioning points are not continuous.

[0035] The initial positioning point allows for accurate correspondence between the initial drilling point and the actual drilling location. In this embodiment of the invention, based on the theoretical coordinates and hole position information of the initial hole position in the Gerber file, the drilling position on the flexible circuit board is determined using the three-point positioning method with the initial positioning point. Drilling is then performed at the drilling position to obtain the initial hole position. It should be noted that the three-point positioning method is a well-known technique among those skilled in the art and will not be elaborated upon here.

[0036] After determining the initial hole position, the position of the new hole needs to be determined based on the previously drilled holes during subsequent drilling. Therefore, based on the determined initial hole position, the expected coordinates of the second hole position are obtained through the positional relationship in the Gerber file.

[0037] S3: Based on the expected theoretical deviations between the second hole position and the initial hole position in terms of distance and direction, determine the local errors in distance and direction respectively; based on the expected theoretical deviations between the second hole position and each initial positioning point in terms of distance and direction, determine the global errors in distance and direction respectively; analyze the distance and direction respectively, and correct the error magnitude by adjusting the deviation ratio between the global error and the local error to obtain the error correction value of the second hole position.

[0038] However, due to material expansion and contraction, clamping stress, or temperature changes, the sheet material will exhibit translational, rotational, and scaling deviations. Material expansion and contraction occur because the sheet material absorbs moisture from the environment before storage and processing, or retains internal stress during manufacturing. When it undergoes baking or environmental changes during processing, it will experience microscopic shrinkage or expansion. This anisotropic or isotropic dimensional change directly manifests as an overall scaling deviation. Secondly, clamping stress is generated during the process of fixing the flexible sheet to the drilling machine's worktable. To achieve flat processing, clamps or vacuum adsorption tables must be used to fix the flexible FPC. However, any uneven locking or adsorption force will apply additional mechanical stress to the sheet material, causing it to be locally stretched or compressed, thus triggering minute translations or rotations, or even complex nonlinear twisting.

[0039] Because the initial hole position is fixed, and the second hole position is determined by the first hole position, but because the substrate is deformed, if the second hole position is determined directly according to the initial hole position, the actual position of the second hole position will differ from the theoretical position, so it needs to be corrected.

[0040] Specifically, the degree of positional error deviation is first analyzed from the perspectives of the initial hole position and the initial positioning point. The deviation is analyzed based on the initial hole position, focusing on the influence of local expansion and contraction rotation between the second hole position and the initial hole position. The deviation is analyzed based on the initial positioning point, focusing on the influence caused by the overall deformation of the substrate board, and the error of the second hole position is corrected.

[0041] Preferably, in this embodiment of the invention, the method for obtaining local errors includes: From a distance perspective, the distance between the predicted coordinates of the second hole and the initial hole is calculated as the actual predicted distance between the two holes. The theoretical distance between the initial and second hole positions is obtained based on the Gerber file. The difference between the actual predicted distance and the theoretical distance is calculated to obtain the local error in the distance of the second hole. For example, if the theoretical distance is 5mm, but due to FPC deformation, such as local extrusion causing a larger hole spacing, the calculated actual predicted distance is 5.05mm, then the local error is 0.05mm.

[0042] From a directional perspective, the orientation angle of the second hole position relative to the initial hole position in the predicted coordinates is calculated as the actual predicted orientation angle. The orientation angle of the second hole position relative to the initial hole position in the theoretical coordinates is obtained based on the Gerber file and is taken as the theoretical orientation angle. The difference between the actual predicted orientation angle and the theoretical orientation angle is calculated to obtain the local error of the second hole position in the direction. For example, if the theoretical orientation angle is 0°, but due to deformation, the calculated actual predicted orientation angle is 1°, then the local error is 1°.

[0043] Preferably, in this embodiment of the invention, the method for obtaining the global error includes: For any initial positioning point, calculate the distance between the predicted coordinates of the second hole and the initial positioning point. This distance is used as the predicted positioning distance between the second hole and the initial positioning point. The theoretical distance between the initial positioning point and the second hole is obtained based on the Gerber file and is used as the theoretical positioning distance. The difference between the predicted and theoretical positioning distances is calculated to obtain the positioning error in distance between the second hole and the initial positioning point. For example, if the theoretical positioning distance is 10mm, due to FPC deformation, such as stretching or rotation during FPC extension, the actual distance side length and the angle along the actual direction will increase. Therefore, the predicted positioning distance is calculated to be 10.1mm, and the positioning error is 0.1mm.

[0044] Calculate the orientation angle of the second hole position relative to the initial positioning point, using this as the predicted orientation angle. Obtain the orientation angle of the second hole position relative to the initial positioning point in theoretical coordinates based on the Gerber file, using this as the theoretical orientation angle. Calculate the difference between the predicted and theoretical orientation angles to obtain the positioning error between the second hole position and the initial positioning point. For example, if the theoretical orientation angle is 30°, but the actual predicted orientation angle calculated due to deformation is 32°, then the positioning error is 2°.

[0045] By comprehensively analyzing the deviations of all positioning points to reflect the global error level, the average of the distance positioning errors between the second hole and all initial positioning points is taken as the global distance error of the second hole. Similarly, the average of the directional angle positioning errors between the second hole and all initial positioning points is taken as the global directional error of the second hole.

[0046] Then, error correction is performed based on the global error between the second hole position and the initial positioning point, as well as the local error between the second hole position and the initial hole position. When correcting the hole position, the correction should not be too large because the drilling position needs to be balanced. However, it is also necessary to ensure that the corrected hole position layout is reasonable and does not affect the quality of the flexible circuit board.

[0047] Preferably, in this embodiment of the invention, the method for obtaining the error correction value includes: Regarding distance, the average of the local and global errors of the second hole position is used as the error mean, reflecting the degree of error in the overall error analysis of distance. The ratio of global to local error is then normalized to obtain a correction weight. When the error of the second hole position is more biased towards local error, the correction degree needs to be slightly smaller to avoid unreasonable circuit board layout due to excessive hole position correction. When it is more biased towards global error, it indicates that the substrate deformation is more severe, and therefore the correction degree is larger.

[0048] It should be noted that normalization is a technique well known to those skilled in the art. The choice of normalization can be linear normalization or standard normalization, etc., and the specific normalization method is not limited here.

[0049] Finally, the product of the correction weight and the error mean is used as the error correction value for the second hole position in terms of distance, quantifying the degree of error that needs to be adjusted in terms of distance.

[0050] Similarly, the error correction value in the direction is analyzed. In the direction, the average of the local error and the global error of the second hole position is used as the error mean, reflecting the overall error level in the direction. The ratio of the global error to the local error is normalized to obtain the correction weight. Through the balancing adjustment of the global error and the local error, the product of the correction weight and the error mean is used as the error correction value of the second hole position in the direction. The specific meaning will not be elaborated here.

[0051] This completes the error analysis for the second hole.

[0052] S4: Correct the expected coordinates of the second hole position by using the error correction value, and correct the coordinates of each hole position to be drilled according to the error correction values ​​of all previous holes.

[0053] The predicted coordinates of the second hole can be corrected based on the error correction values ​​for distance and direction. In this embodiment of the invention, the predicted coordinates of the second hole are shifted towards the theoretical coordinates in the Gerber file. An error correction value is applied to the direction angle, and the distance is corrected based on the distance error correction value. The corrected coordinates of the second hole are then obtained, and drilling is performed. As an example, the error correction value for the direction of the second hole is 2°, the error correction value for the distance is 0.131mm, and the direction angle of the theoretical coordinates is 30°. The predicted coordinates are adjusted by 2° towards the theoretical coordinates, and the hole is moved by 0.131mm. The corrected coordinates are obtained by using the adjusted distance and direction angle, combined with the coordinates of the initial positioning point, and a Cartesian coordinate system transformation formula, ultimately yielding the accurate actual drilling coordinates of the second hole.

[0054] Because there are many holes on the circuit board, and the deformation of the substrate varies at different locations, continuous error analysis is needed for dynamic correction and compensation. For each hole, the closer the hole is to the target location during continuous drilling, the more similar the substrate deformation, and the more reliable the error analysis for that hole. In this embodiment, the holes are arranged in drilling order. To further ensure proximity reference, a preset number of holes preceding the target hole are selected and sorted to obtain the drilling sequence. The preset number of holes is set to 10. If there are fewer than 10 holes, all holes are sorted. The larger the sequence number, the closer the hole is to the target location, the stronger the reference value, and the higher the confidence level of the error analysis.

[0055] In terms of distance, the error correction values ​​of all holes before the hole to be punched are weighted and averaged using the sequence number in the punching sequence as the weight. That is, the sequence number of each hole in the punching sequence is multiplied by the error correction value to obtain the weighted value. The weighted values ​​of all holes in the punching sequence are averaged to obtain the weighted mean. The weighted mean is negatively correlated and normalized to obtain the correction control coefficient of the hole to be punched in terms of distance. The deformation stability is reflected by the historical continuous correction process. When the participating errors are more consistent and smaller, the error analysis stability of batch processing is better, the correction adjustment can be smaller, and therefore the larger the control coefficient, the more error analysis is retained.

[0056] Furthermore, the average of the local and global distance errors at the location to be drilled is taken as the distance error of the location to be drilled. The product of the distance error and the correction control coefficient is taken as the distance error correction value for the location to be drilled. Through continuous dynamic compensation, the reliability and accuracy of subsequent error corrections are adjusted. It should be noted that negative correlation mapping is a technique well-known to those skilled in the art, such as inverse proportional or negative exponential forms, and is not limited here.

[0057] Similarly, in the direction, the error correction values ​​of all holes preceding the hole to be drilled are weighted and averaged using the sequence number in the drilling sequence as the weight. This is then negatively correlated and normalized to obtain the distance correction control coefficient for the hole to be drilled. The mean of the local and global errors in the direction of the hole to be drilled is taken as the direction error of the hole to be drilled. The product of the direction error and the correction control coefficient is taken as the error correction value in the direction of the hole to be drilled. The specific meaning of these values ​​will not be elaborated upon here.

[0058] Finally, the coordinates of the expected coordinates of the hole to be drilled are corrected by the error correction value and the hole is drilled. The coordinates of subsequent holes are corrected in turn, thereby completing the automatic control of the hole coordinate correction of the flexible circuit board.

[0059] In summary, this invention determines the initial positioning point through edge saliency analysis of image data, establishes the correlation between the physical FPC and the ideal design coordinates, and determines a more accurate initial hole position. Further, for the second hole position, it quantifies the deformation deviation between the initial positioning point and the initial hole position, and performs weighted balancing correction by calculating dual-reference errors, considering the different proportions of the global and local influence of possible deformations. This makes the error correction for hole position positioning more accurate and reliable. Finally, the accumulated error correction value is used to continuously and dynamically compensate and correct the holes to be drilled, improving drilling accuracy. This invention quantifies the overall and local deformation, balances the deviation weights in direction and distance for error correction, performs dynamic tracking correction for continuous drilling, reduces batch error accumulation, and improves the accuracy of drilling position in real time.

[0060] This application also provides an automatic drilling control system for flexible printed circuit boards, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the automatic drilling control method for flexible printed circuit boards described above.

[0061] This application also provides a computer device; please refer to [link / reference]. Figure 2 The illustration shows a schematic diagram of a computer device structure according to an embodiment of the present invention. The computer device includes a memory 301, a processor 302, and a computer program 303 stored in the memory 301 and running on the processor 302. When the processor 302 executes the computer program 303, the computer device can execute any of the aforementioned automatic control methods for drilling holes in flexible circuit boards.

[0062] This application also provides a computer program product that, when run on a computer device, enables the computer device to execute any of the aforementioned automatic drilling control methods for flexible circuit boards.

[0063] This application also provides a computer-readable storage medium storing computer program code. When the computer program code is run on a computer device, the computer device can execute any of the aforementioned automatic drilling control methods for flexible circuit boards.

[0064] In the embodiments provided in this application, it should be understood that the computer device, computer program product and computer-readable storage medium provided are all used to perform the corresponding methods provided above, and therefore the beneficial effects they can achieve can be referred to the beneficial effects of the methods provided above, which will not be repeated here.

[0065] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0066] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. An automatic control method for drilling holes in a flexible circuit board, characterized in that, The method includes: Obtain Gerber files and image data of flexible circuit boards; The initial positioning point is determined based on the saliency of features on the edge line in the image data; the initial hole position is obtained by drilling based on the initial positioning point and the hole position information in the Gerber file; the expected coordinates of the second hole position are determined based on the initial hole position. Based on the expected theoretical deviations between the second hole position and the initial hole position in terms of distance and direction, the local errors in distance and direction are determined respectively; based on the expected theoretical deviations between the second hole position and each initial positioning point in terms of distance and direction, the global errors in distance and direction are determined respectively; for each distance and direction, the error correction value of the second hole position is obtained by correcting the error magnitude through the deviation ratio between the global error and the local error. The expected coordinates of the second hole are corrected by using the error correction value, and the position of each hole to be drilled is corrected by using the error correction values ​​of all previous holes.

2. The automatic drilling control method for flexible circuit boards according to claim 1, characterized in that, The method for obtaining the initial positioning point includes: Obtain the edge points of the flexible circuit board boundary in the image data, and calculate the pixel value difference between every two consecutive edge points; use the mean of the difference values ​​corresponding to each edge point as the difference degree of the edge point; Based on the degree of difference between each edge point and other edge points on the boundary, obtain the significance index of each edge point; The edge points are sorted from largest to smallest according to their significance index to obtain a significance sequence; the first three edge points in the significance sequence are used as initial positioning points; the initial positioning points are not continuous.

3. The automatic drilling control method for flexible circuit boards according to claim 2, characterized in that, The methods for obtaining the significance index include: For any edge point, calculate the difference between the edge point and each edge point within a preset local range, and then use the sum of all differences as the neighborhood difference of the edge point. Calculate the ratio of the difference degree of the edge point to the mean difference degree of all edge points to obtain the difference significance of the edge point; By combining the neighborhood dissimilarity and differential significance of the edge point, the significance index of the edge point is obtained.

4. The automatic drilling control method for flexible circuit boards according to claim 1, characterized in that, The method for obtaining the local error includes: Calculate the distance between the predicted coordinates of the second hole and the initial hole, which is taken as the actual predicted distance between the second hole and the initial hole; obtain the distance between the theoretical coordinates of the initial hole and the second hole based on the Gerber file, which is taken as the theoretical distance; calculate the difference between the actual predicted distance and the theoretical distance to obtain the local error of the second hole in terms of distance. Calculate the orientation angle of the second hole position relative to the initial hole position in the expected coordinates, as the actual expected orientation angle; obtain the orientation angle of the second hole position relative to the initial hole position in the theoretical coordinates based on the Gerber file, as the theoretical orientation angle; calculate the difference between the actual expected orientation angle and the theoretical orientation angle to obtain the local error of the second hole position in the direction.

5. The automatic drilling control method for flexible circuit boards according to claim 1, characterized in that, The method for obtaining the global error includes: For any initial positioning point, calculate the distance between the predicted coordinates of the second hole and the initial positioning point, and use it as the predicted positioning distance between the second hole and the initial positioning point; obtain the distance between the theoretical coordinates of the initial positioning point and the second hole based on the Gerber file, and use it as the theoretical positioning distance; calculate the difference between the predicted positioning distance and the theoretical positioning distance to obtain the positioning error in distance between the second hole and the initial positioning point; Calculate the orientation angle of the second hole position relative to the initial positioning point, and use it as the positioning orientation angle; obtain the orientation angle of the second hole position relative to the initial positioning point in the theoretical coordinates based on the Gerber file, and use it as the positioning theoretical orientation angle; calculate the difference between the positioning orientation angle and the positioning theoretical orientation angle to obtain the positioning error between the second hole position and the initial positioning point in the direction. The average of the distance errors between the second hole and all initial positioning points is taken as the global error of the second hole in terms of distance; the average of the orientation angle errors between the second hole and all initial positioning points is taken as the global error of the second hole in terms of orientation.

6. The automatic drilling control method for a flexible circuit board according to claim 1, characterized in that, The method for obtaining the error correction value includes: In terms of distance, the mean of the local error and the global error of the second hole position is used as the error mean; the ratio of the global error to the local error is normalized to obtain the correction weight; the product of the correction weight and the error mean is used as the error correction value of the second hole position in terms of distance. In terms of direction, the average of the local and global errors of the second hole position is used as the error mean; the ratio of the global error to the local error is normalized to obtain the correction weight; the product of the correction weight and the error mean is used as the error correction value of the second hole position in the direction.

7. The automatic drilling control method for flexible circuit boards according to claim 1, characterized in that, The step of correcting the predicted coordinates of the second hole position by using an error correction value includes: The expected coordinates of the second hole are compared with the theoretical coordinates in the Gerber file. The direction angle is deflected by the error correction value, and the distance is corrected based on the distance error correction value to obtain the corrected coordinates of the second hole and then the hole is drilled.

8. The automatic drilling control method for flexible circuit boards according to claim 1, characterized in that, The step of correcting the coordinate position of each hole to be drilled based on the error correction values ​​of all previous holes includes: Arrange the holes in the drilling order to obtain the drilling sequence; In terms of distance, the error correction values ​​of all holes before the hole to be punched are weighted, averaged, and normalized using the sequence number in the punching sequence as the weight, to obtain the correction control coefficient of the hole to be punched in terms of distance; the mean of the local error and the global error of the hole to be punched in terms of distance is taken as the distance error of the hole to be punched; the product of the distance error and the correction control coefficient is taken as the error correction value of the hole to be punched in terms of distance. In terms of direction, the error correction values ​​of all holes before the hole to be drilled are weighted, averaged, and normalized using the sequence number in the drilling sequence as the weight, to obtain the distance correction control coefficient of the hole to be drilled; the mean of the local error and global error of the hole to be drilled is taken as the direction error of the hole to be drilled; the product of the direction error and the correction control coefficient is taken as the error correction value of the hole to be drilled in the direction. The expected coordinates of the hole to be drilled are corrected using the error correction value, and then the hole is drilled.

9. The automatic drilling control method for a flexible circuit board according to claim 1, characterized in that, The method for obtaining the initial hole position includes: Based on the theoretical coordinates and hole position information of the initial hole position in the Gerber file, the drilling position on the flexible circuit board is determined by the three-point positioning method through the initial positioning point, and the hole is drilled at the drilling position to obtain the initial hole position.

10. An automatic drilling control system for flexible printed circuit boards, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the automatic drilling control method for a flexible circuit board as described in any one of claims 1 to 9.

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