PTH slot processing quality detection system based on PCB

Abstract

The invention relates to the technical field of PCB electronic manufacturing, and relates to a PTH slot processing quality detection system based on a PCB. According to the invention, a standard fixed point location on the PCB is automatically identified, and the PCB is fixed to a detection position through adsorption; based on the acquired PCB surface image, acquiring the center coordinate and the contour of the PTH slot, and judging the geometric accuracy by calculating the coordinate deviation and the contour deviation degree of the PTH slot and a standard drawing; if the geometric accuracy is qualified, further stretching into the slotted hole to collect an inner wall image of the copper-plated layer, analyzing the integrity and thickness characteristics of the copper-plated layer, and comprehensively judging the quality of the copper-plated layer based on the integrity and thickness characteristics; and carrying out sampling destructive detection on the PCB which is qualified in quality detection, counting the qualified rate and taking corresponding treatment measures. According to the invention, a full-process and multi-dimensional automatic detection system from the external geometric dimension to the internal plating quality is realized, and the accuracy and reliability of quality detection of the PTH slot of the PCB are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of PCB electronic manufacturing technology, and specifically to a PTH slot processing quality inspection system based on PCB boards. Background Technology

[0002] As electronic devices develop towards miniaturization, high density, and high power, PCBs are gradually upgrading towards multi-layer and high precision. As a key structure for achieving interlayer electrical connections on PCBs, the processing quality of PTH vias has become a core factor affecting PCB performance. With the expansion of PCB industry capacity and the increase in process complexity, the traditional manual inspection mode can no longer meet production needs. Therefore, the development of efficient and accurate processing quality inspection systems has become an important requirement for the industry.

[0003] However, the existing technology has the following problems: 1. The existing method of measuring the inner wall copper plating layer of PTH slots as a whole does not form a layered measurement mechanism for different depths of the slots. It is impossible to accurately obtain the thickness distribution and uniformity of the copper plating layer at different depths, resulting in incomplete detection dimensions and difficulty in fully reflecting the actual quality status of the copper plating layer. This leads to problems such as low efficiency, poor consistency and incomplete detection.

[0004] 2. Existing technologies mostly use a single method to detect the processing quality of PTH slots. While conducting non-destructive testing, they do not consider destructive testing through quantitative sampling, lack a quantitative re-inspection mechanism, and find it difficult to verify the authenticity of non-destructive testing results, thus affecting the accuracy and reliability of PTH slot processing quality detection. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies by providing a PTH slot processing quality inspection system based on PCB boards. By measuring the geometric accuracy of the PTH slot and the integrity and thickness characteristics of the inner wall copper plating layer, combined with quantitative destructive testing, the processing quality of the PTH slot is determined, thereby improving the reliability of quality inspection.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a PTH slot processing quality inspection system based on PCB boards, comprising a detection and positioning module, a geometric accuracy detection module, an internal image acquisition module, a defect judgment module, a quantitative re-inspection module, and a result feedback module. The connection relationships between the modules are as follows: the detection and positioning module is connected to the geometric accuracy detection module; the internal image acquisition module is connected to both the defect judgment module and the geometric accuracy detection module; and the quantitative re-inspection module is connected to both the defect judgment module and the result feedback module.

[0007] Detection and positioning module: Based on the fixed points set in the standard PCB drawings, it identifies and selects the fixed points on the PCB board and performs fixation control.

[0008] Geometric accuracy inspection module: Acquires surface images of the fixed PCB board, obtains the coordinates of the center point of the PTH slot, and determines whether the geometric accuracy of the PTH slot is qualified.

[0009] Internal image acquisition module: If the geometric accuracy is not up to standard, the PTH slot hole processing quality is deemed unqualified; otherwise, based on the coordinates of the center point of the PTH slot hole, the inner wall image of the PTH slot hole is acquired by a probe acquisition device to obtain the defect area of ​​the inner wall image of the PTH slot hole and the copper plating thickness of each detection section.

[0010] Defect Judgment Module: The integrity of the copper plating layer is calculated by the area of ​​the defective region of the PTH slot, the thickness characteristics of the copper plating layer are analyzed by the thickness of the copper plating layer at each inspection section, and the processing quality of the PTH slot is judged based on the integrity and thickness characteristics of the copper plating layer.

[0011] Quantitative re-inspection module: Randomly select samples from qualified PCB boards for destructive testing to obtain the copper plating width characteristics of each vertical section of the PTH slot and determine its processing quality.

[0012] Results feedback module: counts the number of samples that pass the quality test and takes corresponding measures based on the sample pass rate.

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention identifies and selects the fixed points of the PCB board body by setting the fixed points in the standard drawings of the PCB board, and fixes them; the position of the PCB board is accurately corrected to the preset detection state, so as to eliminate the influence of the position and angle deviation of the detection process on image acquisition and subsequent detection results.

[0014] (2) The present invention obtains images of the inner wall of the PTH slot by probing the acquisition device according to the center point coordinates of the PTH slot, and obtains the defect area of ​​the inner wall of the PTH slot and the copper plating thickness of each detection section, providing complete data support for subsequent accurate determination of the processing quality of the PTH slot.

[0015] (3) The present invention calculates the integrity of the copper plating layer by the area of ​​the defective region of the PTH slot, analyzes the thickness characteristics of the copper plating layer by the thickness of the copper plating layer of each test section, and judges the processing quality of the PTH slot based on the integrity and thickness characteristics of the copper plating layer, so as to ensure the conductivity reliability between PCB layers and provide a scientific basis for judging the processing quality of PTH slot.

[0016] (4) The present invention performs destructive testing on PCB boards that have passed image acquisition and inspection, obtains the copper plating thickness characteristics of each vertical section, and judges the quality of the copper plating based on the thickness characteristics. Through cross-verification of destructive testing and image acquisition and inspection, the processing quality of PTH slots can be judged more accurately. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments 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.

[0018] Figure 1 This is a schematic diagram of the system module connections of the present invention.

[0019] Figure 2 This is a schematic diagram illustrating the specific steps of the geometric accuracy detection module in this invention.

[0020] Figure 3 This is a schematic diagram of the process for judging the processing quality of PTH slots in this invention. Detailed Implementation

[0021] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0022] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0023] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0024] This invention automatically identifies standard fixed points on a PCB board and fixes them to the detection position via adsorption. Based on the acquired PCB board surface image, it obtains the center coordinates and outline of the PTH slot. Geometric accuracy is judged by calculating the coordinate deviation and outline deviation from the standard drawing. If the geometric accuracy is qualified, it further probes into the slot to acquire images of the inner wall of the copper plating layer, analyzes the integrity and thickness characteristics of the copper plating layer, and comprehensively judges the quality of the copper plating layer based on the integrity and thickness characteristics. PCB boards that pass the quality inspection are sampled for destructive testing, and the pass rate is calculated, and corresponding processing measures are taken. This invention realizes a fully automated, multi-dimensional inspection system from external geometric dimensions to internal plating quality, significantly improving the accuracy and reliability of PTH slot quality inspection on PCB boards.

[0025] Please see Figure 1 As shown, this invention provides a PTH slot processing quality inspection system based on PCB boards, including a detection and positioning module, a geometric accuracy detection module, an internal image acquisition module, a defect judgment module, a quantitative re-inspection module, and a result feedback module. The connections between the modules are as follows: the detection and positioning module is connected to the geometric accuracy detection module; the internal image acquisition module is connected to both the defect judgment module and the geometric accuracy detection module; and the quantitative re-inspection module is connected to both the defect judgment module and the result feedback module.

[0026] Detection and positioning module: Based on the fixed points set in the standard PCB drawings, it identifies and selects the fixed points on the PCB board and performs fixation control.

[0027] It should be noted that the specific content of the detection and positioning module is as follows: when the PCB board is transferred to the detection area, the board surface is scanned by a high-resolution industrial camera, and a rectangular coordinate system is established based on the fixed points set in the pre-stored standard PCB board drawings to automatically identify and locate the coordinates of the fixed points on the PCB board.

[0028] It should be noted that the rectangular coordinate system is established by taking the midpoint of the line connecting the fixed points as the origin and the line connecting the fixed points as the horizontal axis.

[0029] Move the vacuum adsorption device to the fixed point coordinates and apply negative pressure to adsorb and fix the PCB board, then adjust the PCB board to the preset detection position.

[0030] In a specific example, the specific steps for moving the vacuum adsorption device to a fixed position are as follows: The present invention uses an adsorption device with an integrated double suction cup. The suction cup is positioned vertically facing the horizontal plane of the PCB board. Two coordinate points are obtained on the surface of the PCB board by the vertical projection of the integrated double suction cup. The horizontal and vertical coordinate deviations between the projection point of the midpoint of the line connecting the double suction cups and the origin of the coordinates are calculated. The horizontal and vertical coordinate deviations are moved horizontally until the projection point coincides with the midpoint of the line connecting the fixed position.

[0031] Obtain the coordinates of the integrated dual suction cups projected vertically onto the PCB board surface in the positive direction of the horizontal axis, and calculate the angle between the vector of the line connecting the integrated dual suction cups and the horizontal axis based on these coordinates, which is recorded as the deflection angle.

[0032] Using the midpoint of the line connecting the two suction cups as the center of rotation, when the vertical coordinate of the projection point is negative, rotate the integrated double suction cup counterclockwise; when the vertical coordinate of the projection point is positive, rotate the integrated double suction cup clockwise. The rotation angle is the deflection angle, so that the line connecting the fixed points is parallel to the line connecting the two suction cups. At this time, move the adsorption device vertically downward until it contacts the fixed point on the PCB board.

[0033] It should be noted that adjusting the PCB board to the preset detection position means that the PCB board, which is adsorbed by the vacuum adsorption device driven by the robotic arm, is detached from the conveyor belt, lifted vertically upwards, and rotated to a specific position, laying the foundation for the subsequent geometric accuracy detection module to acquire clear and stable surface images.

[0034] This invention identifies and fixes fixed points on the PCB board by setting fixed points in the standard PCB board drawings; it accurately corrects the position of the PCB board to the preset detection state to eliminate the influence of position and angle deviations during the detection process on image acquisition and subsequent detection results.

[0035] Geometric accuracy inspection module: Acquires surface images of the fixed PCB board, obtains the coordinates of the center point of the PTH slot, and determines whether the geometric accuracy of the PTH slot is qualified.

[0036] like Figure 2 As shown, the geometric accuracy detection module includes: S1, acquiring PCB board surface images through a high-precision industrial camera, obtaining the edge contour of the inner wall of the slot through a sub-pixel contour positioning algorithm, determining the center point of the contour based on the edge contour of the inner wall of the slot, and obtaining the coordinates of the center point according to the established rectangular coordinate system.

[0037] S2. Calculate the deviation between the center point coordinates and the center point coordinates of the PTH slot in the standard drawing. The deviation can be calculated using the Euclidean distance formula to determine the distance between the center point coordinates of the PTH slot and the center point coordinates of the PTH slot in the standard drawing.

[0038] S3. Based on the edge contour of the inner wall of the slot, compare it with the contour of the standard drawing and calculate the contour deviation.

[0039] It should be further explained that the specific method for calculating the contour deviation includes:

[0040] Align the center point coordinates of the PTH slot with the center point coordinates of the PTH slot in the standard drawing, and re-establish a rectangular coordinate system with the coincident center point to obtain the contour point set of the PTH slot.

[0041] Compare the contour point set of the PTH slot with the contour point set in the standard drawing, measure the shortest distance from each point on the PTH slot contour to the contour point in the standard drawing, and take the maximum value among all the shortest distances as the contour deviation.

[0042] S4. Compare the coordinate deviation value and the contour deviation with the corresponding preset deviation threshold. If the coordinate deviation value is greater than the set coordinate deviation threshold or the contour deviation is greater than the set contour deviation threshold, the geometric accuracy is deemed unqualified. Otherwise, the geometric accuracy is deemed qualified. The set coordinate deviation threshold and the set contour deviation threshold need to be determined according to the industry's precision requirements for PCB boards. For details, please refer to the PCB board processing standard database.

[0043] This invention acquires a clear image of the PTH groove on the surface of a PCB board, then obtains the inner wall edge contour and center coordinates of the PTH groove. By comparing it with the standard PCB drawing, coordinate deviation value and contour deviation value are obtained. By comparing the two with the corresponding thresholds, it is determined whether the geometric accuracy is qualified. Parts with unqualified geometric accuracy can be rejected in advance, thus improving the overall inspection efficiency.

[0044] Internal image acquisition module: If the geometric accuracy is not up to standard, the PTH slot hole processing quality is deemed unqualified; otherwise, based on the coordinates of the center point of the PTH slot hole, the inner wall image of the PTH slot hole is acquired by a probe acquisition device to obtain the defect area of ​​the inner wall image of the PTH slot hole and the copper plating thickness of each detection section.

[0045] The acquisition equipment includes a high-resolution industrial camera, an X-ray fluorescence measuring instrument, and a ring light. The high-resolution industrial camera is used to acquire images of the inner wall of the PTH slot to obtain the defect area. The X-ray fluorescence measuring instrument is used to measure the copper plating thickness of each detection section of the PTH slot. The ring light can form a 360° uniform illumination around the slot axis, making the brightness of each circumferential position of the inner wall consistent, clearly restoring the outline features of the copper plating defect, avoiding the omission or misjudgment of defects due to uneven illumination, and providing a high-quality image foundation for subsequent image segmentation and defect area calculation.

[0046] It should be noted that the method for obtaining the defect area and the copper plating thickness of each detection section of the PTH slot inner wall image includes: performing dehazing and noise reduction processing on the PTH slot inner wall image to obtain a grayscale image; using an image segmentation algorithm to divide the grayscale image of the PTH slot inner wall into a normal plating area and a defect area; and calculating the total pixel area of ​​the defect area based on the defect area contour.

[0047] It should be noted that defective areas include recessed areas and protruding nodules in the copper plating layer. The normal plating area on the inner wall of the PTH slot exhibits continuous and stable grayscale values ​​in the grayscale image due to the uniformity of the copper plating. However, the recessed and protruding nodule areas show significant differences in grayscale values ​​compared to the normal area. Based on this characteristic, an adaptive threshold segmentation algorithm is employed. This algorithm automatically analyzes the grayscale distribution pattern of the image to determine the grayscale threshold that distinguishes between normal and defective areas. Then, based on this threshold, the grayscale image is divided into pixel-level segments. Pixels with grayscale values ​​matching the characteristics of normal plating are classified as normal plating areas, while pixels with grayscale values ​​exceeding the threshold range are classified as defective areas.

[0048] The number of pixels in the defective area is counted. Based on the correspondence between pixel size and actual physical size, the counted number of pixels is multiplied by the actual area corresponding to a single pixel to obtain the area of ​​the defective area.

[0049] The PTH slot is divided into test sections at equal intervals along the depth direction. Annular test points are evenly distributed on each section, and the copper plating thickness corresponding to each test point on each test section is collected using an X-ray fluorescence measuring instrument.

[0050] This invention acquires images of the inner wall of a PTH slot by inserting a data acquisition device based on the coordinates of the center point of the PTH slot, and obtains the defect area and copper plating thickness of each detection section of the PTH slot inner wall image, providing complete data support for subsequent accurate determination of the PTH slot processing quality.

[0051] Defect Judgment Module: The integrity of the copper plating layer is calculated by the area of ​​the defective region of the PTH slot, the thickness characteristics of the copper plating layer are analyzed by the thickness of the copper plating layer at each inspection section, and the processing quality of the PTH slot is judged based on the integrity and thickness characteristics of the copper plating layer.

[0052] It should be noted that the specific method for calculating the integrity of the copper plating layer includes: recording the difference between the total pixel area of ​​the detection area of ​​the PTH slot inner wall and the total pixel area of ​​the defect area as the complete pixel area.

[0053] The integrity is defined as the ratio of the area of ​​complete pixels to the total pixel area of ​​the detection region on the inner wall of the PTH slot.

[0054] It should also be noted that the thickness characteristics of the copper plating layer include the average thickness and the degree of thickness fluctuation. The specific analysis method for the thickness characteristics of the copper plating layer includes: selecting the maximum and minimum thickness values ​​of each detection section from the thicknesses corresponding to each annular detection point of each detection section, and calculating the average thickness of each detection section.

[0055] The thickness difference is obtained by the difference between the maximum and minimum thickness values ​​of each test section. The ratio of the thickness difference to the average thickness is used as the degree of thickness fluctuation of the test section.

[0056] like Figure 3 As shown, the method of judging the PTH slot processing quality based on the integrity and thickness characteristics of the copper plating layer includes: W1, when the integrity is lower than the integrity threshold set in the PCB board processing standard database, it is determined that the integrity of the copper plating thickness does not meet the standard; otherwise, it is determined that the integrity of the copper plating thickness meets the standard.

[0057] W2. Compare the average thickness and thickness fluctuation of each test section with the specified thickness range and maximum fluctuation standard value in the PCB board processing standard database.

[0058] W3. When the average thickness of a certain test section is not within the specified thickness range or the thickness fluctuation is higher than the maximum standard value, the copper plating thickness uniformity is determined to be non-compliant with the standard; otherwise, the copper plating thickness uniformity is determined to be compliant with the standard.

[0059] W4. If the integrity or uniformity of the copper plating thickness of the PTH slot does not meet the standard, the processing quality of the PTH slot is deemed unqualified.

[0060] W5. Conversely, if the PTH slot is found to be of acceptable quality, the coordinate deviation value, contour deviation, copper plating integrity, and thickness fluctuation will be comprehensively evaluated to obtain the overall quality score of the PTH slot. The processing quality level of the PTH slot will be determined based on the overall quality score.

[0061] The specific steps for calculating the overall quality score of the PTH slot include: using the product of the integrity and the set total overall quality score as the base score.

[0062] The thickness fluctuation of each test section is averaged to obtain the overall fluctuation of the PTH slot.

[0063] The ratios of coordinate deviation value to set coordinate deviation threshold and contour deviation degree to set contour deviation threshold are obtained respectively. The deduction coefficient is obtained by weighting the ratios of coordinate deviation value to coordinate deviation threshold, contour deviation degree to contour deviation threshold and overall fluctuation degree.

[0064] It should be noted that the weights of the ratio of coordinate deviation value to coordinate deviation threshold, the ratio of contour deviation degree to contour deviation threshold, and the overall fluctuation degree can be set based on industry experience or obtained through a limited number of experimental data. For example, a large number of PCB board samples with known comprehensive quality scores can be collected first, and the ratios of coordinate deviation value to coordinate deviation threshold, contour deviation degree to contour deviation threshold, and overall fluctuation degree of each sample can be extracted. The information entropy of the ratios of coordinate deviation value to coordinate deviation threshold, contour deviation degree to contour deviation threshold, and overall fluctuation degree can be calculated, and their information entropy difference coefficients can be evaluated. The proportion of the information entropy difference coefficients can be converted into the weights of the ratios of coordinate deviation value to coordinate deviation threshold, contour deviation degree to contour deviation threshold, and overall fluctuation degree, and the total weights are 1.

[0065] The difference between the base score and the set passing score for the overall quality rating is obtained, and the product of this difference and the deduction coefficient is used as the deduction score. Since the deduction coefficient is within [0, 1], the difference between the base score and the set passing score for the overall quality rating is used as the base score for deduction. This ensures that the overall quality rating after deduction is always higher than the set passing score for the overall quality rating, and can well reflect the impact of coordinate deviation, contour deviation, and thickness fluctuation on the overall quality rating.

[0066] It should be noted that the total score for the overall quality rating is set at 100 points in this invention.

[0067] All PCBs participating in the comprehensive evaluation are qualified PCBs for image acquisition and detection. Therefore, a passing score for the comprehensive quality score is set. In this invention, the passing score is set to 60 points.

[0068] The difference between the base score and the deducted score is recorded as the overall quality score.

[0069] In one specific example, the specific content of classifying the quality level of qualified PTH slots based on the comprehensive quality score is as follows: the quality level with a comprehensive quality score of 90-100 is classified as excellent, the quality level with a comprehensive quality score of 70-89 is classified as good, and the quality level with a comprehensive quality score of 60-69 is classified as qualified.

[0070] It should be noted that different electronic devices have significantly different performance requirements for PCBs: for example, aerospace equipment requires extremely high reliability, while ordinary consumer electronics require stable basic functions. By using rating levels, products can be classified into excellent, good, and qualified levels. This allows excellent products to be adapted to high-power and high-precision scenarios, while qualified products meet basic functional requirements, thus avoiding cost waste caused by using high-quality products underutilized or equipment failure caused by using low-quality products overutilized.

[0071] This invention calculates the integrity of the copper plating layer by measuring the area of ​​the defective region of the PTH slot, analyzes the thickness characteristics of the copper plating layer by measuring the thickness of the copper plating layer at each test section, and judges the processing quality of the PTH slot based on the integrity and thickness characteristics of the copper plating layer, thus ensuring the conductivity reliability between PCB layers and providing a scientific basis for judging the processing quality of PTH slots.

[0072] Quantitative re-inspection module: Randomly select samples from qualified PCB boards for destructive testing to obtain the copper plating width characteristics of each vertical section of the PTH slot and determine its processing quality.

[0073] The specific content of the quantitative re-inspection module, which needs to be further explained, includes: randomly selecting samples to be inspected from qualified PCB boards according to a set ratio for destructive testing, performing multiple vertical cuts on the PTH slots, and measuring the copper plating width of each vertical cut surface.

[0074] It should be noted that the vertical cut surface needs to pass through the internal slot of PTH to form the vertical cut surface of the copper plating layer in the left and right parts. Measurement points are evenly distributed from top to bottom on each vertical cut surface to measure the width of the copper plating layer at each measurement point.

[0075] Based on the copper plating width at each measurement point corresponding to each vertical cut surface, the maximum and minimum width values ​​in each vertical cut surface are selected, and the average copper plating width and the degree of width fluctuation of each vertical section are calculated.

[0076] The fluctuation of the copper plating width of each vertical section of the PTH slot is compared with the maximum value of the fluctuation standard in the PCB board processing standard database. When the fluctuation of the copper plating width of a certain vertical section is greater than the maximum value of the fluctuation standard, the PTH slot is judged to be unqualified in processing quality; otherwise, the PTH slot is judged to be qualified in processing quality.

[0077] This invention performs destructive testing on samples of PCBs that have passed image acquisition and inspection to obtain the copper plating thickness characteristics of each vertical section. The quality of the copper plating is then judged based on the thickness characteristics. Through cross-validation of destructive testing and image acquisition and inspection, the processing quality of PTH slots can be judged more accurately.

[0078] Results feedback module: counts the number of samples that pass the quality test and takes corresponding measures based on the sample pass rate.

[0079] It should be noted that the sample pass rate is calculated by dividing the number of qualified samples by the number of samples taken. It is used to directly reflect the overall quality level of PTH slot processing in the current batch. When the pass rate is higher than the set pass rate threshold, the batch of products is deemed to be of qualified quality. When the pass rate is lower than the set pass rate threshold, the batch of products is deemed to have quality inspection problems, and the remaining PCB boards in the batch are re-inspected. The pass rate threshold can be set based on industry testing experience.

[0080] This invention calculates the pass rate of sampled products by statistically analyzing the number of qualified samples. By comparing the pass rate with a threshold, it combines destructive testing results with non-destructive testing results to reflect the testing results of the PTH slots in this batch. This can more accurately reflect the processing quality level of the PTH slots in the batch of PCB boards and solve the problem of inaccurate results from non-destructive testing.

[0081] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0082] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0083] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0084] 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.

[0085] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A PTH slot processing quality inspection system based on PCB board, characterized in that, include: The detection and positioning module identifies and controls the fixed points on the PCB board according to the fixed points set in the standard PCB board drawings. The geometric accuracy detection module acquires surface images of the fixed PCB board, obtains the coordinates of the center point of the PTH slot from it, and determines whether the geometric accuracy of the PTH slot is qualified. If the geometric accuracy of the internal image acquisition module is not up to standard, the processing quality of the PTH slot is determined to be unqualified. Otherwise, based on the coordinates of the center point of the PTH slot, the inner wall image of the PTH slot is acquired by the probe acquisition device to obtain the defect area of ​​the inner wall image of the PTH slot and the copper plating thickness of each detection section. The defect judgment module calculates the integrity of the copper plating layer by measuring the area of ​​the defective region of the PTH slot, analyzes the thickness characteristics of the copper plating layer by measuring the thickness of the copper plating layer at each inspection section, and judges the processing quality of the PTH slot based on the integrity and thickness characteristics of the copper plating layer. The quantitative re-inspection module randomly selects samples from qualified PCB boards for destructive testing to obtain the copper plating width characteristics of each vertical cross-section of the PTH slot and determine its processing quality. The results feedback module counts the number of samples that pass the quality test and takes corresponding measures based on the sample pass rate.

2. The PTH slot processing quality inspection system based on PCB board according to claim 1, characterized in that: The detection and positioning module includes: When the PCB board is transferred to the inspection area, the board surface is scanned by a high-resolution industrial camera, and a rectangular coordinate system is established based on the fixed points set in the pre-stored standard PCB board drawings to automatically identify and locate the coordinates of the fixed points on the PCB board. Move the vacuum adsorption device to the fixed point coordinates and apply negative pressure to adsorb and fix the PCB board, then adjust the PCB board to the preset detection position.

3. The PTH slot processing quality inspection system based on PCB board according to claim 2, characterized in that: The geometric accuracy detection module includes: The PCB board surface image is acquired by a high-precision industrial camera, the edge contour of the inner wall of the slot is obtained by a sub-pixel contour positioning algorithm, the center point of the contour is determined based on the edge contour of the inner wall of the slot, and the coordinates of the center point are obtained according to the established rectangular coordinate system. Calculate the deviation between the center point coordinates and the PTH slot center point coordinates in the standard drawing; Based on the edge contour of the inner wall of the slot, compare it with the contour of the standard drawing and calculate the contour deviation. The coordinate deviation value and the contour deviation degree are compared with the corresponding preset deviation thresholds. If the coordinate deviation value is greater than the set coordinate deviation threshold or the contour deviation degree is greater than the set contour deviation threshold, the geometric accuracy is determined to be unqualified; otherwise, the geometric accuracy is determined to be qualified.

4. The PTH slot processing quality inspection system based on PCB board according to claim 3, characterized in that: The specific method for calculating the profile deviation includes: Align the center point coordinates of the PTH slot with the center point coordinates of the PTH slot in the standard drawing, and re-establish a rectangular coordinate system with the coincident center point to obtain the contour point set of the PTH slot. Compare the contour point set of the PTH slot with the contour point set in the standard drawing, measure the shortest distance from each point on the PTH slot contour to the contour point in the standard drawing, and take the maximum value among all the shortest distances as the contour deviation.

5. The PTH slot processing quality inspection system based on PCB board according to claim 1, characterized in that, The method for obtaining the defect area and copper plating thickness of each inspection section of the PTH slot inner wall image includes: The PTH slot inner wall image is dehazed and denoised to obtain a grayscale image. An image segmentation algorithm is used to divide the grayscale image of the PTH slot inner wall into a normal coating area and a defect area. The total pixel area of ​​the defect area is calculated based on the contour of the defect area. The PTH slot is divided into test sections at equal intervals along the depth direction. Annular test points are evenly distributed on each section, and the copper plating thickness corresponding to each test point on each test section is collected using an X-ray fluorescence measuring instrument.

6. The PTH slot processing quality inspection system based on PCB board according to claim 5, characterized in that, The specific method for calculating the integrity of the copper plating layer includes: The difference between the total pixel area of ​​the detection area on the inner wall of the PTH slot and the total pixel area of ​​the defect area is recorded as the complete pixel area. The integrity is defined as the ratio of the area of ​​complete pixels to the total pixel area of ​​the detection region on the inner wall of the PTH slot.

7. The PTH slot processing quality inspection system based on PCB board according to claim 5, characterized in that, The thickness characteristics of the copper plating layer include the average thickness and the degree of thickness fluctuation. Specific analysis methods for the thickness characteristics of the copper plating layer include: From the thicknesses corresponding to the annular detection points of each detection section collected, the maximum and minimum thicknesses of each detection section are selected, and the average thickness of each detection section is calculated. The thickness difference is obtained by the difference between the maximum and minimum thickness values ​​of each test section. The ratio of the thickness difference to the average thickness is used as the degree of thickness fluctuation of the test section.

8. The PTH slot processing quality inspection system based on PCB board according to claim 7, characterized in that, The method of judging the PTH slot processing quality based on the integrity and thickness characteristics of the copper plating layer includes: When the integrity is lower than the integrity threshold set in the PCB board processing standard database, the integrity of the copper plating thickness is determined to be non-compliant with the standard; otherwise, the integrity of the copper plating thickness is determined to be compliant with the standard. The average thickness and thickness fluctuation of each test section are compared with the specified thickness range and maximum fluctuation standard in the PCB board processing standard database. When the average thickness of a certain test section is outside the specified thickness range or the thickness fluctuation is higher than the maximum standard value, the copper plating thickness uniformity is determined to be non-compliant with the standard; otherwise, the copper plating thickness uniformity is determined to be compliant with the standard. If the integrity or uniformity of the copper plating thickness of the PTH slot does not meet the standard, the processing quality of the PTH slot is deemed unqualified. Conversely, if the PTH slot does not meet the quality requirements, the machining quality of the PTH slot is deemed acceptable. The coordinate deviation value, contour deviation, copper plating integrity, and thickness fluctuation are comprehensively evaluated to obtain the overall quality score of the PTH slot. Based on the overall quality score, the machining quality level of the PTH slot is determined.

9. A PCB-based PTH slot processing quality inspection system according to claim 8, characterized in that, The specific steps for calculating the overall quality score of the PTH slot include: The product of completeness and the total score of the overall quality assessment is used as the base score; The thickness fluctuation of each test section is averaged to obtain the overall fluctuation of the PTH slot. The ratio of coordinate deviation value to set coordinate deviation threshold and the ratio of contour deviation degree to set contour deviation threshold are obtained respectively. The deduction coefficient is obtained by weighting the ratio of coordinate deviation value to coordinate deviation threshold, the ratio of contour deviation degree to contour deviation threshold and the overall fluctuation degree. The difference between the base score and the passing score for the overall quality score is obtained, and the product of the difference and the deduction coefficient is used as the deduction score. The difference between the base score and the deducted score is recorded as the overall quality score.

10. A PCB-based PTH slot processing quality inspection system according to claim 1, characterized in that, The specific contents of the quantitative retest module include: In qualified PCB boards, samples to be inspected are randomly selected according to a set ratio for destructive testing. The PTH slots are cut vertically multiple times, and the copper plating width of each vertical cut surface is measured. Based on the copper plating width of each vertical cut surface, the maximum and minimum width values ​​of each vertical cut surface are selected, and the average copper plating width and the degree of width fluctuation of each vertical section are calculated. The fluctuation of the copper plating width of each vertical section of the PTH slot is compared with the maximum value of the fluctuation standard in the PCB board processing standard database. When the fluctuation of the copper plating width of a certain vertical section is greater than the maximum value of the fluctuation standard, the PTH slot is judged to be unqualified in processing quality; otherwise, the PTH slot is judged to be qualified in processing quality.

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