A PCB-based PTH slot hole processing quality detection system

Abstract

The present application relates to the technical field of PCB electronic manufacturing, and relates to a PTH slot hole processing quality detection system based on a PCB board.The present application automatically identifies standard fixed points on a PCB board, and is fixed to a detection position through adsorption; based on a collected PCB board surface image, the center coordinates and contour of a PTH slot hole are obtained, and the geometric precision is judged by calculating the coordinate deviation and contour deviation degree thereof from a standard drawing; if the geometric precision is qualified, the slot hole is further probed into to collect an inner wall image of a copper plating layer, the completeness and thickness characteristics of the copper plating layer are analyzed, and the copper plating layer quality is comprehensively judged based on the completeness and thickness characteristics; the PCB board with qualified quality detection is subjected to destructive detection by sampling, and the qualified rate is counted and corresponding processing measures are taken.The present application realizes a full-process, multi-dimensional automatic detection system from external geometric dimensions to internal plating layer quality, and significantly improves the accuracy and reliability of PTH slot hole quality detection of the PCB board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of PCB electronic manufacturing, and relates to a PTH slot hole processing quality detection system based on a PCB. BACKGROUND

[0002] With the development of electronic devices towards miniaturization, high density and high power, PCB gradually upgrades to multi-layer and high precision, and the processing quality of PTH slot hole, as a key structure for realizing interlayer electrical connection of PCB, becomes a core factor affecting the performance of PCB. With the expansion of production capacity and the improvement of process complexity in the PCB industry, the traditional manual detection mode has been difficult to meet the production demand. Therefore, developing an efficient and accurate processing quality detection system has become an important demand of the industry.

[0003] However, the prior art has the following problems: 1. The existing technology measures the copper plating layer on the inner wall of the PTH slot hole as a whole, does not form a layered measurement mechanism for different depth layers of the slot hole, and cannot accurately obtain the thickness distribution and uniformity of the copper plating layer at different depth positions, resulting in incomplete detection dimension, difficulty in fully reflecting the actual quality state of the copper plating layer, and problems such as low efficiency, poor consistency and incomplete detection.

[0004] 2. The existing technology detects the processing quality of the PTH slot hole through a single means, and at the same time of non-destructive detection, does not consider destructive detection through quantitative sampling, lacks quantitative re-inspection mechanism, and is difficult to verify the authenticity of the non-destructive detection result, resulting in affecting the accuracy and reliability of the PTH slot hole processing quality detection. SUMMARY

[0005] The present application aims to solve the problems of the prior art and provides a PTH slot hole processing quality detection system based on a PCB. By measuring the geometric accuracy of the PTH slot hole and the completeness and thickness characteristics of the inner wall copper plating layer, and combining with quantitative destructive detection, the processing quality of the PTH slot hole is judged, and the reliability of quality detection is improved.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a PTH slot hole processing quality detection system based on a PCB, comprising a detection 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 relationship between the modules is: the detection positioning module is connected with the geometric accuracy detection module, the internal image acquisition module is connected with the defect judgment module and the geometric accuracy detection module respectively, and the quantitative re-inspection module is connected with the defect judgment module and the result feedback module respectively.

[0007] The detection positioning module: according to the fixed point set on the standard drawing of the PCB, the fixed point on the PCB body is recognized and selected, and fixed control is performed.

[0008] Geometric accuracy detection module: collect the surface image of the fixed PCB board, obtain the PTH slot hole center point coordinate from it, and judge whether the geometric accuracy of the PTH slot hole is qualified.

[0009] Internal image acquisition module: if the geometric accuracy is unqualified, it is determined that the PTH slot hole processing quality is unqualified, otherwise, according to the PTH slot hole center point coordinate, the PTH slot hole inner wall image is collected through the probe collection equipment, the defect area of the PTH slot hole inner wall image and the copper plating layer thickness of each detection section are obtained.

[0010] Defect judgment module: the completeness of the copper plating layer is calculated through the defect area of the PTH slot hole, the thickness characteristics of the copper plating layer are analyzed through the copper plating layer thickness of each detection section, and the processing quality of the PTH slot hole is judged according to the completeness and thickness characteristics of the copper plating layer.

[0011] Quantitative re-inspection module: in the qualified PCB board, samples are randomly taken for destructive detection, the copper plating layer width characteristics of each vertical section of the PTH slot hole are obtained, and the processing quality is judged.

[0012] Result feedback module: the number of qualified samples is counted, and corresponding treatment measures are taken based on the sample qualification rate.

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

[0014] (2) the present application collects the PTH slot hole inner wall image through the probe collection equipment according to the center point coordinate of the PTH slot hole, obtains the defect area of the PTH slot hole inner wall image and the copper plating layer thickness of each detection section, and provides complete data support for subsequent accurate determination of the processing quality of the PTH slot hole.

[0015] (3) the present application calculates the completeness of the copper plating layer through the defect area of the PTH slot hole, analyzes the thickness characteristics of the copper plating layer through the copper plating layer thickness of each detection section, and judges the processing quality of the PTH slot hole according to the completeness and thickness characteristics of the copper plating layer, so as to guarantee the reliability of PCB interlayer conduction and provide scientific basis for the processing quality judgment of the PTH slot hole.

[0016] (4) the present application carries out destructive detection on the samples of the image acquisition and detection qualified PCB board, obtains the copper plating layer thickness characteristics of each vertical section, judges the copper plating layer quality according to the thickness characteristics, and more accurately judges the processing quality of the PTH slot hole through the cross verification of destructive detection and image acquisition detection. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the following embodiment descriptions will be briefly introduced. Obviously, the drawings in the following descriptions are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0018] Figure 1 The system module connection diagram of the present application.

[0019] Figure 2 The specific step flow diagram of the geometric precision detection module in the present application.

[0020] Figure 3 The PTH slot hole machining quality judgment step flow diagram in the present application. DETAILED DESCRIPTION

[0021] Various exemplary embodiments of the present application will now be described in detail below with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and values of the components and steps set forth in these embodiments are not intended to limit the scope of the present application unless otherwise specifically stated. It should also be understood that the sizes of the various portions shown in the drawings are not drawn to scale for the purpose of convenience in description.

[0022] The following description of at least one example embodiment is merely illustrative in nature and is in no way intended to limit the scope of the application or its application or uses. Techniques, methods, and devices known to those skilled in the art can not be discussed in detail, but should be considered as part of the specification where appropriate.

[0023] In all examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation. Thus, other examples of the example embodiments can have different values.

[0024] The application realizes a full-process, multi-dimensional automatic detection system from external geometric size to internal plating layer quality, significantly improves the accuracy and reliability of PTH slot hole quality detection of the PCB board.

[0025] Referring to Figure 1 As shown in the drawings, the application provides a PTH slot hole processing quality detection system based on a PCB board, which comprises a detection positioning module, a geometric precision detection module, an internal image acquisition module, a defect judgment module, a quantitative re-inspection module and a result feedback module. The connection relationship between the modules is as follows: the detection positioning module is connected with the geometric precision detection module, the internal image acquisition module is connected with the defect judgment module and the geometric precision detection module respectively, and the quantitative re-inspection module is connected with the defect judgment module and the result feedback module respectively.

[0026] The detection positioning module: according to the fixed point position set in the standard drawing of the PCB board, the fixed point position on the PCB board body is recognized and selected, and fixed control is performed.

[0027] It should be noted that the specific content of the detection positioning module is: when the PCB board is transmitted to the detection area, the board surface is scanned by a high-resolution industrial camera, and a rectangular coordinate system is established according to the fixed point position set in the pre-stored standard drawing of the PCB board. The fixed point position coordinates on the PCB board body are automatically recognized and positioned.

[0028] It should be noted that the establishment method of the rectangular coordinate system is to take the position of the midpoint of the fixed point position connecting line as the origin and the connecting line of the fixed point position as the horizontal axis to establish the rectangular coordinate system.

[0029] The vacuum suction device is moved to the fixed point position coordinates, and negative pressure is applied to suction and fix the PCB board. The PCB board is adjusted to the preset detection position.

[0030] In a specific example, the specific step of moving the vacuum suction device to the fixed point is: the present application adopts a suction device with a double suction disc, the suction disc is in a vertical state facing the horizontal plane of the PCB, two coordinate points of the vertical projection of the double suction disc on the surface of the PCB are obtained, the deviation amount of the projection point of the midpoint of the double suction disc connecting line and the coordinate origin is calculated, the horizontal direction is moved by the deviation amount of the horizontal and vertical coordinates respectively, and the midpoint of the connecting line of the projection point and the fixed point is coincided.

[0031] The coordinate of the vertical projection of the double suction disc on the surface of the PCB in the positive direction of the horizontal axis is obtained, and the angle between the double suction disc connecting vector and the horizontal axis is calculated based on the coordinate, which is recorded as the deflection angle.

[0032] Taking the midpoint of the double suction disc connecting line as the rotation center, when the vertical coordinate of the projection point coordinate is negative, the double suction disc is counterclockwise rotated, and when the vertical coordinate of the projection point coordinate is positive, the double suction disc is clockwise rotated, the rotation angle is the deflection angle, so that the connecting line between the fixed point and the double suction disc is parallel, and then the suction device is vertically moved downward until it contacts the fixed point on the surface of the PCB.

[0033] It should be noted that adjusting the PCB to the preset detection position means that the PCB adsorbed by the vacuum suction device is separated from the conveying belt, vertically lifted up and rotated to a specific position by the mechanical arm, which lays a foundation for the subsequent geometric precision detection module to collect clear and stable surface images.

[0034] The present application identifies and selects the fixed point of the PCB body through the fixed point set by the standard drawing of the PCB, and fixes it; the position of the PCB is accurately corrected to the preset detection state, so as to eliminate the influence of position and angle deviation in the detection process on image acquisition and the influence of subsequent detection results.

[0035] Geometric precision detection module: collect the surface image of the fixed PCB, obtain the PTH slot hole center point coordinate from it, and judge whether the geometric precision of the PTH slot hole is qualified.

[0036] As shown in Figure 2 The geometric precision detection module comprises the following steps: S1, collecting the surface image of the PCB by a high-precision industrial camera, obtaining the edge profile of the inner wall of the slot hole by a sub-pixel contour positioning algorithm, determining the profile center point based on the edge profile of the inner wall of the slot hole, and obtaining the center point coordinate according to the established rectangular coordinate system.

[0037] S2, calculating the deviation value of the center point coordinate and the PTH slot hole center point coordinate in the standard drawing, wherein the deviation value can be calculated by the Euclidean distance formula to calculate the distance between the center point coordinate of the PTH slot hole and the PTH slot hole center point coordinate in the standard drawing.

[0038] S3, according to the edge profile of the inner wall of the slot hole, the standard drawing profile is overlapped and compared, and the profile deviation is calculated.

[0039] Need to be explained is that the specific method of calculating the profile deviation includes:

[0040] The center point coordinates of the PTH slot hole are overlapped with the center point coordinates of the PTH slot hole in the standard drawing, a rectangular coordinate system is re-established with the overlapped center point, and the profile point set of the PTH slot hole is obtained.

[0041] The profile point set of the PTH slot hole is compared with the profile point set in the standard drawing, the shortest distance from each point on the profile of the PTH slot hole to the profile point in the standard drawing is measured, and the maximum value in all the shortest distances is taken as the profile deviation.

[0042] S4, the coordinate deviation value and the profile deviation are compared with the corresponding preset deviation threshold value respectively, when the coordinate deviation value is greater than the set coordinate deviation threshold value or the profile deviation is greater than the set profile deviation threshold value, it is determined that the geometric precision is unqualified, otherwise it is determined that the geometric precision is qualified, wherein the set coordinate deviation threshold value and the set profile deviation threshold value need to be determined according to the precision requirement of PCB in the industry, and the specific can query the PCB processing standard database.

[0043] The present application obtains the clear image of the PTH slot on the surface of the PCB, then obtains the edge profile of the inner wall of the PTH slot and the center coordinate point, compares with the standard drawing of the PCB, obtains the coordinate deviation value and the profile deviation value, compares the two with the corresponding threshold value respectively, judges whether the geometric precision is qualified, and removes the geometric precision unqualified piece in advance, improves the overall detection efficiency.

[0044] The internal image acquisition module: if the geometric precision is unqualified, it is determined that the PTH slot hole machining quality is unqualified, otherwise according to the PTH slot hole center point coordinate, the PTH slot hole inner wall image is collected through the probe collection equipment, the defect area of the PTH slot hole inner wall image and the plating copper layer thickness of each detection section are obtained.

[0045] The collection equipment includes a high-resolution industrial camera, an X-ray fluorescence measuring instrument and a ring light, wherein the high-resolution industrial camera is used for collecting the PTH slot hole inner wall image to obtain the defect area, the X-ray fluorescence measuring instrument is used for measuring the plating copper layer thickness of each detection section of the PTH slot hole, and the ring light can form 360° uniform illumination around the slot hole axis, so that the brightness of each circumferential position of the inner wall is consistent, the profile characteristics of the plating copper layer defect are clearly restored, the defect is avoided due to uneven illumination, and high-quality image basis is provided for subsequent image segmentation and defect area calculation.

[0046] It should be noted that the method for obtaining the defect area of the PTH hole inner wall image and the plating copper layer thickness of each detection section comprises: performing fog removal and noise reduction processing on the PTH hole inner wall image to obtain a gray image, dividing the gray image of the PTH hole inner wall into a normal plating layer area and a defect area by using an image segmentation algorithm, and calculating the total pixel area of the defect area according to the defect area profile.

[0047] It should be noted that the defect area includes a recessed area and a protruding nodule area of the plating copper layer; the normal plating layer area of the PTH hole inner wall is uniform due to the plating copper layer, and presents the characteristics of continuity and stable gray value in the gray image; and the recessed area and the protruding nodule area of the plating copper layer have obvious differences in gray value from the normal area. Based on this characteristic, an adaptive threshold segmentation algorithm is used to automatically analyze the gray distribution rule of the image and determine the gray threshold for distinguishing the normal area and the defect area; and then the gray image is divided at the pixel level according to the threshold, the pixels with gray values conforming to the characteristics of the normal plating layer are classified into the normal plating layer area, and the pixels with gray values exceeding the threshold range are classified into the defect area.

[0048] The number of pixels in the defect area is counted, and the area of the defect area is obtained by multiplying the number of counted pixels by the actual area corresponding to a single pixel according to the corresponding relationship between the pixel size and the actual physical size.

[0049] The PTH hole is equally divided into detection sections along the depth direction, ring-shaped detection points are uniformly arranged on each section, and an X-ray fluorescence measuring instrument is used to collect the plating copper layer thickness corresponding to each detection point of each detection section.

[0050] The present application provides complete data support for subsequent accurate determination of the processing quality of the PTH hole by collecting the PTH hole inner wall image according to the central point coordinate of the PTH hole, obtaining the defect area of the PTH hole inner wall image and the plating copper layer thickness of each detection section.

[0051] The defect judgment module calculates the completeness of the plating copper layer by the defect area of the PTH hole, analyzes the thickness characteristics of the plating copper layer by the plating copper layer thickness of each detection section, and judges the processing quality of the PTH hole according to the completeness and thickness characteristics of the plating copper layer.

[0052] It should be noted that the specific method for calculating the completeness of the plating copper layer comprises: taking the difference between the total pixel area of the PTH hole inner wall detection area and the total pixel area of the defect area as the complete pixel area.

[0053] The ratio of the complete pixel area to the total pixel area of the PTH hole inner wall detection area is taken as the completeness.

[0054] It also needs to be explained that the thickness characteristics of the copper plating layer include thickness average value and thickness fluctuation degree, and the specific analysis method of the thickness characteristics of the copper plating layer comprises: screening the maximum value and the minimum value of the thickness of each detection section from the thickness corresponding to each annular detection point of each detection section, and calculating the thickness average value of each detection section.

[0055] The thickness difference is obtained by the difference between the maximum value and the minimum value of the thickness of each detection section, and the ratio of the thickness difference to the thickness average value is taken as the thickness fluctuation degree of the detection section.

[0056] As shown in Figure 3 PTH slot hole processing quality is judged according to the integrity and thickness characteristics of the copper plating layer, which comprises: W1, when the integrity is lower than the set integrity threshold value in the PCB processing standard database, it is determined that the copper plating thickness integrity does not meet the standard, otherwise it is determined that the copper plating thickness integrity meets the standard.

[0057] W2, the thickness average value and the thickness fluctuation degree of each detection section are compared with the specified thickness value range and the maximum value of the fluctuation degree standard in the PCB processing standard database respectively.

[0058] W3, when the thickness average value of a certain detection section is not within the specified thickness value range or the thickness fluctuation degree is higher than the maximum value of the fluctuation degree standard, it is determined that the copper plating thickness uniformity does not meet the standard, otherwise it is determined that the copper plating thickness uniformity meets the standard.

[0059] W4, when the copper plating thickness integrity or the copper plating thickness uniformity of the PTH slot hole does not meet the standard, it is determined that the PTH slot hole processing quality is unqualified.

[0060] W5, otherwise, it is determined that the PTH slot hole processing quality is qualified, and the coordinate deviation value, the profile deviation degree, the copper plating layer integrity and the thickness fluctuation degree are comprehensively scored and evaluated to obtain the comprehensive quality score of the PTH slot hole, and the processing quality grade of the PTH slot hole is determined based on the comprehensive quality score.

[0061] The specific steps of calculating the comprehensive quality score of the PTH slot hole comprise: taking the product of the integrity and the set comprehensive quality score total score as the base score.

[0062] The thickness fluctuation degrees of each detection section are processed by mean value to obtain the overall fluctuation degree of the PTH slot hole.

[0063] The ratio of the coordinate deviation value to the set coordinate deviation threshold value and the ratio of the profile deviation degree to the set profile deviation threshold value are obtained respectively, and the ratio of the coordinate deviation value to the coordinate deviation threshold value, the ratio of the profile deviation degree to the profile deviation threshold value and the overall fluctuation degree are weighted to obtain the deduction coefficient.

[0064] It should be noted that the weight of the ratio of the coordinate deviation value to the coordinate deviation threshold, the ratio of the profile deviation to the profile deviation threshold and the overall fluctuation degree can be set according to industry experience, or can be obtained through a limited number of test data. For example, a large number of PCB samples with known comprehensive quality scores are first collected, the ratio of the coordinate deviation value to the coordinate deviation threshold, the ratio of the profile deviation to the profile deviation threshold and the overall fluctuation degree of each sample are extracted, the information entropy of the ratio of the coordinate deviation value to the coordinate deviation threshold, the ratio of the profile deviation to the profile deviation threshold and the overall fluctuation degree is calculated, the information entropy difference coefficient is evaluated, and the proportion of the information entropy difference coefficient is converted into the weight of the ratio of the coordinate deviation value to the coordinate deviation threshold, the ratio of the profile deviation to the profile deviation threshold and the overall fluctuation degree, and the total weight is 1.

[0065] The difference between the base score and the qualified score line of the set comprehensive quality score is obtained, and the product of the difference and the deduction coefficient is taken as the deduction score. Since the deduction coefficient is in [0, 1], the difference between the base score and the qualified score line of the set comprehensive quality score is taken as the deduction base score, so that the comprehensive quality score after deduction is always higher than the qualified score line of the set comprehensive quality score, and can well reflect the influence of the coordinate deviation value, the profile deviation and the thickness fluctuation degree on the comprehensive quality score.

[0066] It should be noted that the total score of the set comprehensive quality score in the present application is 100 points.

[0067] Since the PCBs participating in the comprehensive evaluation are all image acquisition and detection qualified PCBs, the qualified score line of the set comprehensive quality score is set, and the qualified score line in the present application is set to 60 points.

[0068] The difference between the base score and the deduction score is taken as the comprehensive quality score.

[0069] In a specific example, the specific content of dividing the qualified PTH slot hole quality level based on the comprehensive quality score is that the quality level with a comprehensive quality score of 90-100 points is divided into an excellent level, the quality level with a comprehensive quality score of 70-89 points is divided into a good level, and the quality level with a comprehensive quality score of 60-69 points is divided into a qualified level.

[0070] It should be noted that the performance requirements of different electronic devices for PCBs are significantly different. For example, aerospace equipment requires extremely high reliability, and ordinary consumer electronics require stable basic functions. Through the score level, excellent, good and qualified products can be classified, so that the excellent level is suitable for high-power and high-precision scenes, the qualified level meets the basic functional requirements, and cost waste caused by excellent low use or device failure caused by low-quality high use is avoided.

[0071] The application calculates the completeness of the copper plating layer through the PTH slot hole defect area, analyzes the thickness characteristics of the copper plating layer through the thickness of the copper plating layer of each detection section, judges the PTH slot hole processing quality according to the completeness and thickness characteristics of the copper plating layer, guarantees the PCB interlayer conductive reliability, and provides a scientific basis for PTH slot hole processing quality judgment.

[0072] The quantitative re-inspection module: in the quality qualified PCB board, randomly take samples for destructive detection, obtain the copper plating layer width characteristics of each vertical section of the PTH slot hole, and judge the processing quality.

[0073] Among the need to be supplemented, the specific content of the quantitative re-inspection module includes: in the quality qualified PCB board, randomly take samples for destructive detection according to the set proportion, cut the PTH slot hole vertically for multiple times, and measure the copper plating layer width of each vertical cutting surface.

[0074] It should be noted that the cutting surface of vertical cutting needs to pass through the internal slot hole of the PTH to form the left and right copper plating layer vertical cutting surfaces, and uniformly arrange the measurement points from top to bottom on each vertical cutting surface to measure the copper plating layer width of each measurement point.

[0075] According to the copper plating layer width of each measurement point corresponding to each vertical cutting surface, the maximum value and the minimum value of the width of each vertical cutting surface are screened, and the average value of the copper plating layer width of each vertical section and the width fluctuation degree are calculated.

[0076] The copper plating layer width fluctuation degree of each vertical section of the PTH slot hole is compared with the maximum value of the fluctuation degree standard in the PCB board processing standard database, when the copper plating layer width fluctuation degree of a certain vertical section is greater than the maximum value of the fluctuation degree standard, it is judged that the processing quality of the PTH slot hole is unqualified, otherwise it is judged that the processing quality of the PTH slot hole is qualified.

[0077] The application carries out destructive detection on the sampled PCB board detected by image acquisition, obtains the copper plating layer thickness characteristics of each vertical section, judges the quality of the copper plating layer according to the thickness characteristics, and more accurately judges the processing quality of the PTH slot hole through the cross verification of destructive detection and image acquisition detection.

[0078] The result feedback module: count the number of qualified samples, and take corresponding processing measures based on the sample qualification rate.

[0079] It should be noted that the sample pass rate refers to the ratio of the number of qualified samples to the number of extracted samples to calculate the pass rate of the extracted samples, which is used to intuitively reflect the overall level of the current batch PTH slot hole processing quality, when the pass rate is higher than the set pass rate threshold, it is determined that the quality of the current batch product is qualified, when the pass rate is lower than the set pass rate threshold, it is determined that there is a problem with the quality detection result of the current batch, and the remaining PCB boards in the current batch are re-detected, and the pass rate threshold can be set according to the detection experience in the industry.

[0080] The application calculates the pass rate of the sampled samples by counting the qualified number of the sampled samples, reflects the detection result of the PTH slot hole of the current batch by comparing with the threshold value, and reflects the PTH slot hole processing quality level of the batch PCB board by combining the destructive detection result with the non-destructive detection result, so as to solve the problem of inaccurate non-destructive detection result.

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

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

[0083] In addition, the functional modules in each embodiment of the present application can be integrated in one processing module, or each module can exist physically, or two or more modules can be integrated in one module.

[0084] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0085] Finally, the above is only a preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A PCB-based PTH slot hole processing quality detection system, characterized in that, The method comprises the following steps: A detection positioning module identifies and selects the fixed point on the PCB body according to the fixed point set in the standard drawing of the PCB and fixes the control; A geometric precision detection module collects the surface image of the fixed PCB and obtains the PTH slot hole center point coordinate from the image to determine whether the geometric precision of the PTH slot hole is qualified; If the geometric precision is unqualified, it is determined that the PTH slot hole processing quality is unqualified, otherwise, according to the PTH slot hole center point coordinate, the PTH slot hole inner wall image is collected by the probe collection equipment, the defect area of the PTH slot hole inner wall image and the plating copper layer thickness of each detection section are obtained, including: the PTH slot hole inner wall image is processed to obtain a gray image, the gray image of the PTH slot hole inner wall is divided into a normal plating layer area and a defect area by using an image segmentation algorithm, and the total pixel area of the defect area is calculated according to the defect area profile; the PTH slot hole is equally divided into detection sections along the depth direction, ring detection points are uniformly arranged on each section, and the plating copper layer thickness corresponding to each detection point of each detection section is collected by using an X-ray fluorescence measuring instrument; A defect judgment module calculates the completeness of the plating copper layer by the PTH slot hole defect area, including: the difference between the total pixel area of the PTH slot hole inner wall detection area and the total pixel area of the defect area is taken as the complete pixel area; the ratio of the complete pixel area to the total pixel area of the PTH slot hole inner wall detection area is taken as the completeness; The thickness characteristics of the plating copper layer are analyzed by the plating copper layer thickness of each detection section, and the PTH slot hole processing quality is judged according to the completeness and thickness characteristics of the plating copper layer; A quantitative re-inspection module randomly selects samples for destructive testing in the qualified PCBs to obtain the plating copper layer width characteristics of each vertical section of the PTH slot hole and judge the processing quality thereof; The specific content of the quantitative re-inspection module comprises the following steps: in the qualified PCBs, samples are randomly selected for destructive testing according to a set proportion, the PTH slot hole is vertically cut multiple times, and the plating copper layer width of each vertical cutting surface is measured; the maximum value and the minimum value of the plating copper layer width of each vertical cutting surface are selected according to the plating copper layer width of each vertical cutting surface, and the average value and the width fluctuation degree of the plating copper layer width of each vertical section are calculated; the plating copper layer width fluctuation degree of each vertical section of the PTH slot hole is compared with the maximum standard fluctuation degree in the PCB processing standard database, when the plating copper layer width fluctuation degree of a certain vertical section is greater than the maximum standard fluctuation degree, it is determined that the PTH slot hole processing quality is unqualified, otherwise, it is determined that the PTH slot hole processing quality is qualified; A result feedback module counts the number of samples with qualified processing quality and takes corresponding processing measures based on the sample qualification rate.

2. The PCB-based PTH slot hole processing quality detection system according to claim 1, characterized in that: The detection positioning module comprises the following steps: When the PCB is transmitted to the detection area, the board surface is scanned by a high-resolution industrial camera, a rectangular coordinate system is established according to the fixed point set in the pre-stored standard drawing of the PCB, and the fixed point coordinate on the PCB body is automatically identified and positioned; 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 PCB-based PTH slot hole processing quality detection system 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 PCB-based PTH slot hole processing quality detection system 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 PCB-based PTH slot hole processing quality detection system according to claim 1, 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.

6. The PCB-based PTH slot hole processing quality detection system according to claim 5, 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 determined to be qualified. The coordinate deviation value, contour deviation, copper plating integrity and thickness fluctuation are comprehensively evaluated to obtain the comprehensive quality score of the PTH slot. The machining quality level of the PTH slot is determined based on the comprehensive quality score.

7. The PCB-based PTH slot hole processing quality detection system according to claim 6, characterized in that, The specific steps for calculating the overall quality score of PTH slots include: The product of the completeness and the set total score of the comprehensive quality score is taken as a base score; The thickness fluctuation degrees of each detection section are processed by averaging to obtain an overall fluctuation degree of the PTH slot hole; The ratio of the coordinate deviation value to the set coordinate deviation threshold value and the ratio of the profile deviation to the set profile deviation threshold value are obtained respectively, and the ratio of the coordinate deviation value to the coordinate deviation threshold value, the ratio of the profile deviation to the profile deviation threshold value, and the overall fluctuation degree are weighted to obtain a deduction coefficient; The difference between the base score and the qualified score line of the set comprehensive quality score is obtained, and the product of the difference and the deduction coefficient is taken as a deduction score; The difference between the base score and the deduction score is taken as the comprehensive quality score.

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