PCB (Printed Circuit Board) alignment method and testing machine

Abstract

The invention relates to the technical field of printed circuit board manufacturing, and discloses a PCB alignment method and a testing machine, the PCB alignment method comprises the following steps: obtaining alignment information of a first PCB, the alignment information comprising first theoretical coordinates of at least two reference points in the first PCB in the first PCB; collecting images of at least two reference points; based on the images of the at least two reference points, the coordinates of the at least two reference points in the test machine are identified, and first actual coordinates of the at least two reference points are obtained; based on the first actual coordinate and the first theoretical coordinate, analyzing the coordinate deviation of the test machine relative to the first PCB to obtain deviation information; and performing motion compensation on a motion mechanism of the test machine based on the deviation information to realize alignment of the first PCB. According to the invention, the problem of inaccurate alignment of the PCB can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board manufacturing, in particular to a PCB alignment method and a test machine. BACKGROUND

[0002] In flying probe testing, a printed circuit board (PCB) may not match a test machine due to clamping deviation or board deformation, resulting in inaccurate alignment of the PCB. SUMMARY

[0003] The present application provides a PCB alignment method and a test machine to solve the problem of inaccurate alignment of a PCB.

[0004] In a first aspect, the present application provides a PCB alignment method applicable to a test machine, which comprises: obtaining alignment information of a first PCB, the alignment information comprising first theoretical coordinates of at least two reference points in the first PCB in the first PCB; collecting images of the at least two reference points; identifying coordinates of the at least two reference points in the test machine based on the images of the at least two reference points to obtain first actual coordinates of the at least two reference points; analyzing coordinate deviation of the test machine relative to the first PCB based on the first actual coordinates and the first theoretical coordinates to obtain deviation information; performing motion compensation on a motion mechanism of the test machine based on the deviation information to realize alignment of the first PCB.

[0005] In a second aspect, the present application provides a test machine, which comprises: a test machine body comprising a probe, a vision module, and a motion mechanism; a control device for executing the above-mentioned PCB alignment method.

[0006] The PCB alignment method provided by the embodiments of the present application obtains first theoretical coordinates of at least two reference points in a first PCB, identifies first actual coordinates of the at least two reference points based on collected images of the at least two reference points, and then compares and analyzes the first actual coordinates and the first theoretical coordinates, which can accurately quantify deviation information between the test machine and the first PCB. Furthermore, motion compensation can be performed on a motion mechanism of the test machine based on the deviation information to eliminate alignment errors, thereby realizing accurate alignment of the first PCB and the test machine and improving the accuracy of alignment of the first PCB. BRIEF DESCRIPTION OF DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the description of the embodiments or the prior art. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0008] Figure 1 is a schematic diagram of an application scenario according to an embodiment of the present application; Figure 2 is a first flowchart of a PCB alignment method according to an embodiment of the present application; Figure 3 is a structural block diagram of a PCB alignment device according to an embodiment of the present application; Figure 4 is a hardware structure diagram of a control device according to an embodiment of the present application. DETAILED DESCRIPTION

[0009] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0010] It can be understood that, before using the technical solutions disclosed in the embodiments of the present application, the type, use range, use scenario and the like of the personal information involved in the present application should be informed to the user and the authorization of the user should be obtained according to relevant laws and regulations through appropriate means.

[0011] The terms "first", "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0012] The first PCB board alignment is a key pre-process of the flying probe test. The core of the PCB board alignment is to achieve the accurate matching of the PCB board and the coordinate system of the test machine within 5 minutes through the cooperation of the mechanical coarse positioning and the visual fine calibration, so as to solve the test point misalignment problem of the first PCB board caused by the clamping deviation and the board deformation. The final goal of the PCB board alignment is that the deviation between the actual coordinate of the test point of the PCB board after the alignment and the theoretical coordinate of the test point is within 0.01 mm, the time consumption of the single PCB board alignment is within 3 minutes, which lays a foundation for the coordinate reuse of the subsequent batch test, and avoids the risks of the probe hitting the board and the test misjudgment caused by the PCB board alignment deviation.

[0013] As an optional application scenario of the embodiment of the application, as shown in Figure 1 The application is applied to a test machine. The test machine includes a control device 101 and a test machine body 102. The control device 101 is used for controlling a motion mechanism, a visual module and a probe in the test machine body 102, so as to complete the alignment of the first PCB board. In actual application, the control device controls the visual module to collect the image of the reference point in the first PCB board or collect the image of the probe, so as to realize the accurate identification of the first actual coordinate of the reference point and the first center coordinate of the probe. Further, the control device controls the probe to move to the test point of the first PCB board, analyzes the deviation of the test machine relative to the first PCB board, and obtains the deviation information. Finally, the control device controls the motion mechanism based on the deviation information, drives the motion mechanism of the test machine to perform motion compensation, so as to realize the accurate alignment of the first PCB board. The visual module adopts a camera, and the motion mechanism includes a clamping tool, an X-axis motion mechanism, a Y-axis motion mechanism, a Z-axis motion mechanism and a θ-axis motion mechanism.

[0014] According to the embodiment of the application, a PCB board alignment method embodiment is provided. It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a group of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0015] In this embodiment, a PCB board alignment method is provided, which can be used for a test machine, such as a test machine body, a control device, Figure 2 The flowchart of the PCB board alignment method according to the embodiment of the application is shown in Figure 2 The flowchart includes the following steps: In step S201, the alignment information of the first PCB board is obtained, and the alignment information includes the first theoretical coordinate of at least two reference points in the first PCB board in the first PCB board.

[0016] The first PCB board is the first PCB board to be tested by the test machine.

[0017] Specifically, the state of the test machine is checked after the test machine is started. First, it is confirmed whether the movement mechanism of the test machine moves normally, including confirming whether the X-axis movement mechanism, the Y-axis movement mechanism and the Z-axis movement mechanism are free of jamming and abnormal sound, and whether the rotation accuracy of the θ-axis movement mechanism meets the requirement that the repeat positioning error is not more than ±0.1°. At the same time, by shooting the standard PCB calibration board, the imaging clarity of the vision module is checked to ensure that the edge of the shot image is free of blur and distortion phenomenon, and the light source brightness of the vision module is adjusted to 300-400 cd / m² (adapted to the material of most first PCB boards).

[0018] Further, after the state check of the test machine is completed, the GERBER file or test program of the first PCB board is imported into the test machine software to obtain the key parameters of the first PCB board. The key parameters of the first PCB board include the size (length, width and thickness) of the first PCB board, the number of reference points, the diameter of the reference points (the conventional diameter is 0.5-1.0 mm), the first theoretical coordinates of the reference points in the first PCB board, and the second theoretical coordinates of all test points in the first PCB board, to ensure that the data is consistent with the actual PCB board. Among them, the number of reference points is greater than or equal to 2, and the reference points distributed in diagonal lines are preferred.

[0019] Specifically, the alignment information of the first PCB board is obtained from the GERBER file or test program of the first PCB board.

[0020] Step S202, images of at least two reference points are collected.

[0021] Specifically, the images of at least two reference points are collected by the vision module on the test machine.

[0022] Step S203, based on the images of at least two reference points, the coordinates of at least two reference points in the test machine are identified to obtain the first actual coordinates of at least two reference points.

[0023] Specifically, based on the identification algorithm in the test machine software, the images of at least two reference points collected are identified to identify the coordinates of at least two reference points in the test machine, so as to obtain the first actual coordinates of at least two reference points.

[0024] Step S204, based on the first actual coordinates and the first theoretical coordinates, the coordinate deviation of the test machine relative to the first PCB board is analyzed to obtain deviation information.

[0025] Optionally, the deviation information includes at least one of coordinate translation deviation and coordinate rotation deviation.

[0026] Specifically, the deviation of the test machine relative to the first PCB is calculated according to the first actual coordinates of the reference points and the first theoretical coordinates of the reference points, and then the deviation information is obtained.

[0027] In step S205, the motion mechanism of the test machine is compensated based on the deviation information, so as to realize the alignment of the first PCB.

[0028] In actual application, when the origin of the test machine and the origin of the first PCB do not coincide, the origin of the test machine and the origin of the first PCB need to be aligned, so as to realize the alignment of the first PCB.

[0029] Specifically, according to the deviation information of the test machine relative to the first PCB, the test machine software converts the deviation information into test machine motion compensation instructions, and drives the motion mechanism of the test machine to perform motion compensation, so as to realize the alignment of the first PCB.

[0030] The PCB alignment method provided in the embodiment can obtain the first theoretical coordinates of at least two reference points in the first PCB, identify the first actual coordinates of the at least two reference points according to the collected images of the at least two reference points, and then compare and analyze the first actual coordinates and the first theoretical coordinates, so as to accurately quantify the deviation information between the test machine and the first PCB. Furthermore, the motion mechanism of the test machine can be compensated according to the deviation information, so as to eliminate the alignment error, realize the accurate alignment of the first PCB and the test machine, and improve the accuracy of the alignment of the first PCB.

[0031] In some optional embodiments, the image of the at least two reference points collected in the above step S202 includes: for each reference point, based on the first theoretical coordinates of the reference point, the visual module of the test machine is controlled to move towards the position of the reference point to collect the image of the reference point.

[0032] Specifically, before the visual module of the test machine is controlled to move towards the position of the reference point, the tooling and auxiliary tooling need to be prepared, including preparing the clamping tooling (such as vacuum chuck tooling, edge positioning tooling) special for the first PCB, ensuring that the clamping tooling positioning pin matches the test machine workbench positioning hole (the gap between the tooling positioning pin and the test machine workbench is not more than 0.005 mm), preparing a dust-free cloth and isopropyl alcohol to clean the oil stains and dust on the surface of the first PCB, and using a 0.01 mm precision feeler gauge to check the gap between the first PCB and the clamping tooling.

[0033] Specifically, before the visual module of the test machine is controlled to move towards the position of the reference point, the first PCB needs to be pre-processed, including checking the appearance of the first PCB, such as that the first PCB has no warping and deformation and the edge perpendicularity error of the first PCB is not more than 0.02 mm / m, wherein the edge perpendicularity error is used to measure the deviation degree between the edge of the first PCB and the ideal vertical state, and isopropyl alcohol is used to clean the surface of the first PCB with a dust-free cloth, and the reference point area is focused on to avoid stains affecting the recognition of the visual module. If the first PCB has slight warping (such as warping degree not more than 0.5 mm), the warping area of the first PCB needs to be marked, and the test points in the warping area are focused on for calibration during alignment.

[0034] Specifically, before the visual module of the test machine is controlled to move towards the position of the reference point, the first PCB needs to be pre-processed, including checking the appearance of the first PCB, such as that the first PCB has no warping and deformation and the edge perpendicularity error of the first PCB is not more than 0.02 mm / m, wherein the edge perpendicularity error is used to measure the deviation degree between the edge of the first PCB and the ideal vertical state, and isopropyl alcohol is used to clean the surface of the first PCB with a dust-free cloth, and the reference point area is focused on to avoid stains affecting the recognition of the visual module. If the first PCB has slight warping (such as warping degree not more than 0.5 mm), the warping area of the first PCB needs to be marked, and the test points in the warping area are focused on for calibration during alignment.

[0035] Further, after the preparation of the tooling and auxiliary tool, the pre-processing of the first PCB and the installation of the first PCB are completed, the test machine is controlled to move in the X and Y axes, so that the visual module moves towards the first theoretical coordinates of the reference point, and the position error between the actual arrival position of the visual module and the first theoretical coordinates is not more than ±2 mm.

[0036] Further, through the "jog control" function of the test machine operation panel, the step length of the X-axis movement mechanism and the Y-axis movement mechanism of the test machine is manually adjusted to 0.1 mm, and after the step length is adjusted, the test machine is controlled to move in the X and Y axes until the reference point can be clearly observed in the camera field of view (without precise alignment, the reference point only needs to be completely present in the field of view), so as to collect the image of the reference point.

[0037] Alternatively, at least two reference points can be included in the camera field of view one by one by moving the X and Y axes to switch the single camera field of view, or at least two reference points can be included in the camera field of view at the same time by using multiple cameras, which is not limited here.

[0038] In addition, a feeler gauge with an accuracy of 0.01 mm is also needed to check the fitting gap between the first PCB and the clamping tooling. If the feeler gauge can be inserted into the gap and the gap depth is greater than 1 mm, the pressure of the clamping tooling needs to be adjusted again (such as the vacuum chuck tooling can increase the vacuum degree, and the mechanical tooling can adjust the force of the pressure block), so as to ensure that the gap is not more than 0.01 mm.

[0039] The PCB alignment method provided in the embodiment enables the vision module of the test machine to move towards the positions of the reference points, so that at least two reference points enter the field of view of the vision module, and the images of the reference points are collected, thereby providing data basis for subsequent visual recognition of the reference points under the test machine.

[0040] In some optional embodiments, the step S203 of identifying the coordinates of the at least two reference points in the test machine based on the images of the at least two reference points to obtain the first actual coordinates of the at least two reference points comprises: For each reference point, edge detection is performed based on the image of the reference point to obtain edge information of the reference point, and center fitting is performed based on the edge information to obtain the first actual coordinates of the reference point.

[0041] Specifically, for the image of each reference point, the test machine software starts the "reference point recognition" function to automatically identify the first actual coordinates of the reference point. First, edge detection is performed on the image of the reference point to obtain edge information of the reference point, and then center fitting is performed on the edge information to obtain the first actual coordinates of the reference point. The fitting error of the center fitting is not more than ±0.002 mm.

[0042] The PCB alignment method provided in the embodiment effectively overcomes the positioning deviation caused by image blur and edge noise by performing edge detection and center fitting on the images of the reference points, thereby achieving accurate identification of the first actual coordinates of the at least two reference points, providing reliable position data for calibration of the alignment of the first PCB and the test machine, and improving the accuracy of the alignment of the first PCB and the test machine.

[0043] In some optional embodiments, the PCB alignment method further comprises: In step a1, if the first actual coordinates of the reference point are not identified, the area image of the reference point is obtained in response to an area selection operation on the image of the reference point, and the identification parameters for edge detection are adjusted to obtain adjusted identification parameters.

[0044] Specifically, when the reference point is oxidized or scratched, the first actual coordinates of the reference point cannot be identified. At this time, the area of the image of the reference point is selected by operating the operation panel of the test machine, the area image of the reference point is manually framed, and the test machine software automatically optimizes the identification parameters for edge detection of the area image of the reference point to obtain adjusted identification parameters.

[0045] Optionally, the identification parameters can be contrast threshold values or resolutions, which are not limited here.

[0046] In step a2, edge detection is performed on the area image based on the adjusted identification parameters to obtain the first actual coordinates of the reference point.

[0047] Specifically, if the first actual coordinates of the fiducials are not recognized (e.g., the test machine software prompts "fiducials not recognized" or "fiducial edge incomplete"), a first abnormality indication is generated. The first abnormality indication is used to indicate that a first abnormality processing is performed. The first abnormality processing includes: (1) cleaning the surface of the fiducials with isopropyl alcohol to remove oxidation and stains; (2) adjusting the light source brightness of the camera or the camera exposure time, for example, increasing or decreasing 50 cd / m2 based on the light source brightness used in step a2, or fine-tuning the camera exposure time in the range of 50-200 μs; (3) if the fiducials are damaged, re-designating a backup fiducial in the test machine software, and the backup fiducial has been marked in the GERBER file of the first PCB board.

[0048] In some optional embodiments, the PCB board alignment method further includes: Step b1, obtaining an actual distance between the at least two fiducials based on the first actual coordinates between the at least two fiducials.

[0049] Specifically, the actual distance between the at least two fiducials is calculated based on the first actual coordinates between the at least two fiducials. Taking two fiducials as an example, the actual distance between the two fiducials is represented by the following formula:

[0050] wherein, L is the actual distance between the two fiducials, X2 is the horizontal coordinate of the first actual coordinate of the second fiducial, X1 is the horizontal coordinate of the first actual coordinate of the first fiducial, Y2 is the vertical coordinate of the first actual coordinate of the second fiducial, Y1 is the vertical coordinate of the first actual coordinate of the second fiducial.

[0051] Step b2, obtaining a theoretical distance between the at least two fiducials based on the first theoretical coordinates between the at least two fiducials.

[0052] Specifically, the theoretical distance between the at least two fiducials is calculated based on the first theoretical coordinates between the at least two fiducials. Taking two fiducials as an example, the theoretical distance between the two fiducials is represented by the following formula:

[0053] wherein, L is the theoretical distance between the two fiducials, X2 is the horizontal coordinate of the first theoretical coordinate of the second fiducial, X1 is the horizontal coordinate of the first theoretical coordinate of the first fiducial, Y2 is the vertical coordinate of the first theoretical coordinate of the second fiducial, and Y1 is the vertical coordinate of the first theoretical coordinate of the second fiducial.

[0054] Step b3, if the distance error between the actual distance and the theoretical distance is greater than the preset distance error threshold, re-identify the first actual coordinates of the at least two reference points.

[0055] Specifically, if the distance error |(L'-L) / L| between the actual distance and the theoretical distance is greater than the preset distance error threshold 0.1%, the test machine software prompts "abnormal reference point identification", and the first actual coordinates of the at least two reference points need to be identified again after cleaning the reference points.

[0056] The PCB alignment method provided in the embodiment calculates the actual distance and the theoretical distance between the reference points according to the first actual coordinates and the first theoretical coordinates, and then compares the distance error of the actual distance and the theoretical distance with the preset distance error threshold. If the distance error is greater than the preset distance error threshold, an abnormality is prompted and the first actual coordinates of the reference points are re-identified. The alignment error caused by the identification deviation of the reference points can be identified and corrected, and the accuracy of the first PCB alignment is improved.

[0057] In some optional embodiments, the step S204 of analyzing the coordinate deviation of the test machine relative to the first PCB based on the first actual coordinates and the first theoretical coordinates to obtain the deviation information includes: Step c1, obtaining the coordinate translation deviation of the test machine relative to the first PCB based on the first actual coordinates and the corresponding first theoretical coordinates of the same reference point.

[0058] The coordinate translation deviation refers to the linear displacement amount of the actual position of the first PCB relative to the theoretical position in the X-axis and Y-axis directions of the test machine when the first PCB is actually placed, and reflects the translation misplacement of the first PCB in the plane.

[0059] Optionally, the coordinate translation deviation can be obtained based on the first actual coordinates and the corresponding first theoretical coordinates of one reference point from the at least two reference points, or the deviation of the first actual coordinates and the corresponding first theoretical coordinates of each reference point can be processed by averaging to obtain the coordinate translation deviation, which is not limited here.

[0060] Specifically, taking the first reference point as an example, the coordinate translation deviation of the test machine relative to the first PCB is calculated based on the first actual coordinates and the first theoretical coordinates of the reference point. The coordinate translation deviation can be represented by the following formula:

[0061]

[0062] wherein, is the coordinate translation deviation in the X-axis direction, a coordinate translation deviation of the Y axis.

[0063] Step c2, based on the first actual coordinates and the first theoretical coordinates, a first reference line and a second reference line formed by the at least two reference points are respectively constructed, and the rotation angle between the first reference line and the second reference line is analyzed to obtain a coordinate rotation deviation of the test machine relative to the first PCB.

[0064] The coordinate rotation deviation refers to the difference between the actual rotation angle and the theoretical rotation angle of the first PCB when the first PCB is actually placed, and reflects the rotation misplacement of the first PCB in the plane. The first reference line is a line segment formed according to the first actual coordinates of the at least two reference points, and the second reference line is a line segment formed according to the first theoretical coordinates of the at least two reference points.

[0065] Specifically, the coordinate rotation deviation of the test machine relative to the first PCB is obtained by calculating the rotation angle between the first reference line under the test machine and the second reference line under the first PCB. The coordinate rotation deviation is represented by the following formula:

[0066] Wherein, θ is the coordinate rotation deviation of the test machine relative to the first PCB.

[0067] Specifically, if the coordinate rotation deviation exceeds the safe rotation range of the equipment, that is, if the coordinate rotation deviation θ is greater than ±5°, a second abnormality indication is generated. The second abnormality indication is used to indicate a second abnormality processing. The second abnormality processing includes: (1) manually checking whether the direction of the first PCB clamping tooling is reversed, such as mistakenly installing the "TOP surface" as the "BOTTOM surface"; (2) reacquiring the image of the reference point and identifying the first actual coordinates of the reference point.

[0068] Step c3, taking the coordinate translation deviation and the coordinate rotation deviation as the deviation information.

[0069] The PCB alignment method provided in the embodiment calculates the coordinate translation deviation and the coordinate rotation deviation according to the first actual coordinates and the first theoretical coordinates, realizes the quantitative analysis of the position deviation of the first PCB, and significantly improves the alignment accuracy of the first PCB.

[0070] In some optional embodiments, the motion compensation of the motion mechanism of the test machine based on the deviation information in the above step S205 to realize the alignment of the first PCB includes: Step d1, based on the first actual coordinates between the at least two reference points, an actual distance between the at least two reference points is obtained.

[0071] Specifically, reference can be made to step b1, which is not repeated here.

[0072] Step d2, obtaining a theoretical distance between the at least two reference points based on the first theoretical coordinates between the at least two reference points.

[0073] Specifically, reference can be made to step b2, which will not be repeated here.

[0074] Step d3, obtaining a size correction coefficient of the first PCB based on a ratio of the actual distance to the theoretical distance.

[0075] Specifically, when the first PCB has slight scaling (e.g. thermal deformation caused after soldering), the ratio K = L' / L of the actual distance to the theoretical distance is calculated. If the K value is within the range of 0.999-1.001, the first PCB is within the normal scaling range; if the K value exceeds the range of 0.999-1.001, the test machine software prompts "abnormal board type", and the test machine software automatically introduces a size correction coefficient to scale and compensate the K value, so as to restore the K value to the range of 0.999-1.001.

[0076] Step d4, performing motion compensation on the motion mechanism of the test machine based on the deviation information and the size correction coefficient, so as to realize the alignment of the first PCB.

[0077] Specifically, according to the deviation information and the size correction coefficient, the test machine software generates test machine motion instructions to drive the motion mechanism of the test machine to perform motion compensation. For example, if the test machine has coordinate translation deviation relative to the first PCB, the X-axis motion mechanism or the Y-axis motion mechanism of the test machine is executed for translation compensation; if the test machine has coordinate rotation deviation relative to the first PCB, the θ-axis motion mechanism of the test machine is executed for rotation compensation with the reference point as the rotation center.

[0078] Further, after the motion mechanism of the test machine completes the motion compensation, the vision module of the test machine reacquires the at least two reference points. If each deviation in the deviation information of the test machine after completing the motion compensation relative to the first PCB is less than the corresponding deviation threshold, it is determined that the alignment of the first PCB is completed. If the deviation information of the test machine after completing the motion compensation relative to the first PCB satisfies the preset deviation range, the process of identifying the reference points, calculating the deviation information and performing the motion compensation is reperformed. If each deviation in the deviation information is still greater than or equal to the corresponding deviation information threshold after reperforming the process, adjustment is made through manual intervention. Wherein, each deviation less than the corresponding deviation information threshold includes: X-axis coordinate translation deviation less than a preset X-axis deviation threshold, Y-axis coordinate translation deviation less than a preset Y-axis deviation threshold, and θ-axis coordinate rotation deviation less than a preset coordinate rotation deviation threshold.

[0079] The PCB alignment method provided by the embodiment compensates the scaling deformation of the first PCB by the size correction coefficient, so as to ensure the size accuracy of the board type. According to the multivariate motion compensation of the coordinate translation deviation information and the coordinate rotation deviation information, the position of the first PCB can be accurately corrected, and the accuracy of the alignment of the first PCB is improved.

[0080] In some optional embodiments, the alignment information further includes a second theoretical coordinate of a test point in the first PCB on the first PCB; and the method further includes: Step e1, moving the probe of the test machine to the second theoretical coordinate of a first test point in the test points.

[0081] Specifically, to ensure the alignment accuracy covering all the test points of the first PCB, the representative first test points are selected from the test points for verification, so as to avoid local deviation.

[0082] In actual application, one first test point is selected from each of the four corners and the central region of the first PCB, and the first test point far away from the reference point is preferentially selected, so as to obtain five first test points, and the second theoretical coordinates of the first test points are recorded. Then, the probe of the test machine is moved to the second theoretical coordinate of a first test point in the test points.

[0083] Step e2, capturing the image of the probe, and identifying the coordinate of the probe in the test machine based on the image of the probe, to obtain the center point coordinate of the probe.

[0084] Specifically, the image of the probe is captured by the camera, and the coordinate of the probe in the test machine is identified, to obtain the center point coordinate of the probe.

[0085] Step e3, if the coordinate deviation between the center point coordinate and the second theoretical coordinate of the first test point is greater than a preset deviation threshold, the coordinate of the first test point in the test machine is corrected.

[0086] Optionally, the preset deviation threshold can be any value in 0.04-0.06 mm, which is not limited herein.

[0087] Specifically, if the coordinate deviation between the center point coordinate after alignment and the second theoretical coordinate of the first test point is greater than the preset deviation threshold and there is no local deformation, a third abnormality indication is generated. The third abnormality indication is used to indicate that a third abnormality processing is performed. The third abnormality processing includes: (1) checking whether the clamping tool of the first PCB board is loose and whether the vacuum degree meets the standard; (2) excluding the error in identification, and re-identifying the first actual coordinate of the reference point; (3) if the coordinate deviation is still greater than the preset deviation threshold after (1) and (2) are performed, the difference between the actual size and the theoretical size of the first PCB board is measured, and it is judged whether the board type is out of tolerance, for example, the actual length is 0.1mm longer than the theoretical length, and the first PCB board size compensation value needs to be manually input in the test machine software.

[0088] The PCB alignment method provided by the embodiment avoids local deviation by selecting a representative first test point for verification, and can comprehensively detect the positioning accuracy of different regions of the first PCB board. Based on the coordinate deviation between the center point coordinate and the second theoretical coordinate of the first test point, the alignment deviation can be found and corrected, and the reliability and accuracy of the alignment in the test link of the first PCB board are effectively improved.

[0089] In some optional embodiments, the correction of the coordinate of the first test point in the test machine in the step e3 includes: Step e31, determining a second test point within a preset range of the first test point.

[0090] Specifically, if the coordinate deviation between the center point coordinate and the second theoretical coordinate of the first test point is greater than the preset deviation threshold, the second test point within the preset range of the first test point is determined from the plurality of test points.

[0091] Step e32, analyzing the offset of the first test point relative to the at least two reference points to obtain a first offset condition.

[0092] Specifically, based on the first theoretical coordinate of the first test point and the first actual coordinate of the at least two reference points, the first offset condition of the first test point relative to the at least two reference points is determined.

[0093] Step e33, analyzing the offset of the second test point relative to the at least two reference points to obtain a second offset condition.

[0094] Specifically, based on the second theoretical coordinate of the second test point and the first actual coordinate of the at least two reference points, the second offset condition of the second test point relative to the at least two reference points is determined.

[0095] Step e34, determining the deformation condition of the first PCB board within the preset range based on the first offset condition and the second offset condition.

[0096] Step e35, if the first PCB board is deformed within the preset range, the coordinates of the first test point in the coordinate system of the testing machine are corrected.

[0097] The first offset condition is represented by a translational offset.

[0098] Specifically, if the first offset condition of the first test point relative to the at least two reference points is different from the second offset condition of the second test point relative to the at least two reference points (for example, the second test point has no deviation relative to the at least two reference points, and the first test point is deviated to the left relative to the at least two reference points), it is considered that the coordinates of the first test point are identified incorrectly, and the coordinates of the first test point need to be identified again. If the first offset condition of the first test point relative to the at least two reference points is the same as the second offset condition of the second test point relative to the at least two reference points (for example, the first test point is deviated to the left relative to the at least two reference points, and the second test point is also deviated to the left relative to the at least two reference points), it is considered that the first PCB board is deformed within the preset range, and the coordinates of the first test point in the coordinate system of the testing machine need to be corrected. It should be noted that only the coordinates of the first test point in the coordinate system of the testing machine are corrected, which does not affect the global coordinate system.

[0099] In some optional embodiments, the PCB alignment method further comprises: Step f1, if the coordinate deviation between the center point coordinates and the second theoretical coordinates of the first test point is less than or equal to a preset deviation threshold, the model of the first PCB board is obtained.

[0100] Step f2, based on the model and the deviation information, alignment of a second PCB board of the same model is realized.

[0101] Specifically, if the coordinate deviation between the center point coordinates and the second theoretical coordinates of the first test point is less than or equal to a preset deviation threshold, the model of the first PCB board is obtained. At the same time, “coordinate locking” is clicked in the testing machine software, and the X-axis deviation information, Y-axis deviation information, θ-axis deviation information and K value of the first PCB board are saved as an alignment template, and subsequent second PCB boards of the same model as the first PCB board can directly call the alignment template for alignment without repeated alignment.

[0102] The PCB alignment method provided in this embodiment, when the first PCB board is completed, the model thereof is obtained, and combined with the deviation information, subsequent second PCB boards of the same model can be directly completed, avoiding the efficiency loss caused by repeated measurement and calculation, and significantly improving the efficiency of PCB alignment in batch production.

[0103] In some optional embodiments, after the alignment is completed, the accuracy and efficiency of the alignment result are tested, comprising: Specifically, the precision inspection includes: (1) verifying whether the deviation of the first actual coordinates of the reference points from the first theoretical coordinates is not more than ±0.01 mm; (2) randomly selecting 20 test points from the first PCB, verifying the deviation of the second theoretical coordinates of each test point from the first center coordinates of the probe, and performing mean value processing on the 20 deviations to verify whether the average deviation is not more than ±0.012 mm and the maximum deviation is not more than ±0.015 mm; (3) repeating the alignment for the first PCB for three times, verifying whether the standard deviation of the coordinate translation deviation of the three times of alignment is not more than ±0.003 mm and whether the coordinate rotation deviation of the three times of alignment is not more than ±0.01°.

[0104] The efficiency inspection includes: (1) from clamping the first PCB to locking the coordinates, the total time consumption is not more than 3 minutes, wherein the mechanical coarse alignment (i.e., collecting the image of the reference points) is not more than 1 minute, the visual fine alignment (i.e., identifying the first actual coordinates of the reference points) is not more than 1.5 minutes, and the deviation verification between the first center coordinates and the second theoretical coordinates of the first test point is not more than 0.5 minutes; (2) after the second PCB of the same type is called for alignment template, verifying whether the time consumption of the alignment is not more than 1 minute and whether the verification of the first test point is not needed (only the deviation of the first actual coordinates of the two reference points from the first theoretical coordinates needs to be checked).

[0105] As an application embodiment of the embodiment of the present application, for the PCB type produced for a long time, a preset alignment template is created in the test software in advance, the alignment template contains information such as the tool type, the light source parameter, and the reference point coordinates, the first PCB can directly call the preset alignment template during alignment, and the parameter adjustment time in the alignment process is reduced. Moreover, the test machine is equipped with double cameras (corresponding to the diagonal directions of the first PCB respectively), can identify two reference points at the same time, reduces the moving time of camera switching the field of view, and shortens the identification time of the first actual coordinates of the reference points to within 1 minute. Before alignment, an automatic cleaning function is used, an automatic cleaning nozzle is additionally installed beside the tool, and is used to spray a small amount of isopropyl alcohol mist to automatically clean the reference points before alignment, thereby reducing the manual cleaning steps.

[0106] In the embodiment, a PCB alignment device is also provided, which is used to implement the above-mentioned embodiments and preferred embodiments, and will not be described again. As used below, the term "module" can be a combination of software and / or hardware that implements a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware, or a combination of software and hardware is also possible and contemplated.

[0107] The embodiment provides a PCB alignment device, as shown in Figure 3 , comprising: The data acquisition module 301 is configured to acquire alignment information of the first PCB board, and the alignment information comprises first theoretical coordinates of at least two reference points in the first PCB board.

[0108] The image acquisition module 302 is configured to acquire images of the at least two reference points.

[0109] The first processing module 303 is configured to identify coordinates of the at least two reference points in the test machine based on the images of the at least two reference points, and obtain first actual coordinates of the at least two reference points.

[0110] The second processing module 304 is configured to analyze a coordinate deviation of the test machine relative to the first PCB board based on the first actual coordinates and the first theoretical coordinates, and obtain deviation information.

[0111] The alignment module 305 is configured to perform motion compensation on a motion mechanism of the test machine based on the deviation information, so as to realize alignment of the first PCB board.

[0112] In some optional embodiments, the image acquisition module 302 comprises: An image acquisition unit is configured to, for each reference point, control a vision module of the test machine to move towards a position of the reference point based on the first theoretical coordinates of the reference point, so as to acquire an image of the reference point.

[0113] In some optional embodiments, the first processing module 303 comprises: A first identification unit is configured to, for each reference point, perform edge detection based on the image of the reference point to obtain edge information of the reference point, and perform center fitting based on the edge information to obtain the first actual coordinates of the reference point.

[0114] In some optional embodiments, the PCB board alignment device further comprises: A first distance module is configured to obtain an actual distance between the at least two reference points based on the first actual coordinates of the at least two reference points.

[0115] A second distance module is configured to obtain a theoretical distance between the at least two reference points based on the first theoretical coordinates of the at least two reference points.

[0116] A third processing module is configured to, if a distance difference between the actual distance and the theoretical distance is greater than a preset distance threshold, re-identify the first actual coordinates of the at least two reference points.

[0117] In some optional embodiments, the second processing module 304 comprises: A first deviation unit is configured to obtain a coordinate translation deviation of the test machine relative to the first PCB board based on the first actual coordinates and the corresponding first theoretical coordinates of the same reference point.

[0118] a second deviation unit, configured to construct a first reference line and a second reference line based on the first actual coordinates and the first theoretical coordinates respectively, and analyze a rotation angle between the first reference line and the second reference line to obtain a coordinate rotation deviation of the testing machine relative to the first PCB.

[0119] a third deviation unit, configured to take the coordinate translation deviation and the coordinate rotation deviation as the deviation information.

[0120] In some optional embodiments, the alignment module 305 comprises: a size correction unit, configured to obtain a size correction coefficient of the first PCB based on a ratio of the actual distance and the theoretical distance.

[0121] an alignment unit, configured to perform motion compensation on a motion mechanism of the testing machine based on the deviation information and the size correction coefficient, so as to realize alignment of the first PCB.

[0122] In some optional embodiments, the alignment information further comprises second theoretical coordinates of the test points in the first PCB, and the PCB alignment apparatus further comprises: a moving module, configured to control the probe of the testing machine to move to the second theoretical coordinates of a first test point in the test points.

[0123] a second acquisition module, configured to acquire an image of the probe, and identify coordinates of the probe in the testing machine based on the image of the probe, to obtain a center point coordinate of the probe.

[0124] a first correction module, configured to correct the coordinates of the first test point in the testing machine if a coordinate deviation between the center point coordinate and the second theoretical coordinates of the first test point is greater than a preset deviation threshold.

[0125] In some optional embodiments, the first correction module comprises: a first determination unit, configured to determine a second test point in a preset range of the first test point.

[0126] a first analysis unit, configured to analyze a first offset condition of the first test point relative to the at least two reference points.

[0127] a second analysis unit, configured to analyze a second offset condition of the second test point relative to the at least two reference points.

[0128] a third analysis unit, configured to determine a deformation condition of the first PCB in the preset range based on the first offset condition and the second offset condition.

[0129] The fourth analysis unit is configured to correct the coordinates of the first test point in the testing machine if the first PCB board is deformed within a preset range.

[0130] In some optional embodiments, the PCB board alignment device further comprises: The first obtaining module is configured to obtain the model of the first PCB board if the coordinate deviation between the center point coordinates and the second theoretical coordinates of the first test point is less than or equal to a preset deviation threshold.

[0131] The template construction module is configured to construct an alignment template based on the model and the deviation information, and the alignment template is used for alignment of a second PCB board of the same model.

[0132] The PCB board alignment device provided by the embodiments of the present application can execute the PCB board alignment method provided by any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of the execution method. The further function description of each of the above modules and units is the same as that of the corresponding embodiments, and will not be repeated here.

[0133] In the present embodiment, a testing machine is also provided, as shown in Figure 1 The testing machine comprises a testing machine body and a control device. The testing machine body comprises a probe, a vision module and a motion mechanism.

[0134] Specifically, the vision module adopts a camera, and the motion mechanism comprises a clamping tool, an X-axis motion mechanism, a Y-axis motion mechanism, a Z-axis motion mechanism and a θ-axis motion mechanism.

[0135] Specifically, the control device is configured to execute the above PCB board alignment method.

[0136] Referring to Figure 4 , Figure 4 A structural schematic diagram of a control device provided by the embodiments of the present application is provided.

[0137] Specific reference is made to Figure 4 , which shows a structural schematic diagram of a control device suitable for use to implement the control device in the embodiments of the present application. The control device can comprise a processor (such as a central processor, a graphics processor, etc.) 401, which can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 402 or programs loaded from a storage 408 into a random access memory (RAM) 403. In the RAM 403, various programs and data required for operation of the control device are also stored. The processor 401, the ROM 402 and the RAM 403 are connected to each other through a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0138] Generally, the following devices can be connected to the I / O interface 405: input devices 406 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, and the like; output devices 407 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, and the like; storage devices 408 including, for example, a magnetic tape, a hard disk, and the like; and communication devices 409. The communication devices 409 can allow the control device to communicate wirelessly or wired with other devices to exchange data. Although Figure 4 The control device is shown with various devices, but it is understood that not all of the shown devices are required to be implemented or present, and more or fewer devices can alternatively be implemented or present.

[0139] In particular, the processes described above with reference to the flowcharts can be implemented as a computer software program according to embodiments of the present application. For example, embodiments of the present application include a computer program product comprising a computer program carried on a non-transitory computer readable medium, the computer program containing program code for performing the methods illustrated by the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via the communication devices 409, or installed from the storage devices 408, or installed from the ROM 402. When the computer program is executed by the processor 401, the above-described functions defined in the PCB board alignment method of embodiments of the present application are performed.

[0140] Figure 4 The control device shown is merely an example and should not limit the functions and scope of use of embodiments of the present application.

[0141] Embodiments of the present application also provide a computer readable storage medium, the above-mentioned method according to embodiments of the present application can be implemented in hardware, firmware, or as computer code that can be recorded on a storage medium, or be originally stored in a remote storage medium or a non-transitory machine readable storage medium and downloaded through a network and stored in a local storage medium, so that the method described herein can be processed by such software stored on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk or a solid state disk, etc.; further, the storage medium can also include a combination of the above types of storage. It can be understood that the computer, processor, microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, processor or hardware, the PCB board alignment method shown in the above embodiments is implemented.

[0142] Part of the present application can be applied as a computer program product, for example, computer program instructions, when executed by a computer, through the operation of the computer, can invoke or provide the method and / or technical solutions according to the present application. Those skilled in the art should understand that the form of computer program instructions in computer readable medium includes but is not limited to source files, executable files, installation package files and the like, and accordingly, the way of computer program instructions executed by computer includes but is not limited to: the computer directly executes the instructions, or the computer compiles the instructions and then executes the corresponding compiled program, or the computer reads and executes the instructions, or the computer reads and installs the instructions and then executes the corresponding installed program. Here, the computer readable medium can be any available computer readable storage medium or communication medium accessible to the computer.

[0143] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. A PCB board alignment method, characterized in that, The method is suitable for a testing machine, and the method comprises: obtaining alignment information of a first PCB board, the alignment information comprising first theoretical coordinates of at least two reference points in the first PCB board; collecting images of the at least two reference points; identifying coordinates of the at least two reference points in the testing machine based on the images of the at least two reference points to obtain first actual coordinates of the at least two reference points; analyzing coordinate deviation of the testing machine relative to the first PCB board based on the first actual coordinates and the first theoretical coordinates to obtain deviation information; performing motion compensation on a motion mechanism of the testing machine based on the deviation information to realize alignment of the first PCB board.

2. The PCB board alignment method of claim 1, wherein, The collecting of the images of the at least two reference points comprises: for each of the reference points, controlling a vision module of the testing machine to move towards a position of the reference point based on the first theoretical coordinates of the reference point to collect an image of the reference point.

3. The PCB board alignment method of claim 1, wherein, The identifying of the coordinates of the at least two reference points in the testing machine based on the images of the at least two reference points to obtain the first actual coordinates of the at least two reference points comprises: for each of the reference points, performing edge detection based on the image of the reference point to obtain edge information of the reference point, and performing center fitting based on the edge information to obtain the first actual coordinates of the reference point.

4. The PCB board alignment method of claim 1, wherein, The method further comprises: obtaining an actual distance between the at least two reference points based on the first actual coordinates of the at least two reference points; obtaining a theoretical distance between the at least two reference points based on the first theoretical coordinates of the at least two reference points; if a distance error between the actual distance and the theoretical distance is greater than a preset distance error threshold, re-identifying the first actual coordinates of the at least two reference points.

5. The PCB board alignment method of claim 1, wherein, The analyzing of the coordinate deviation of the testing machine relative to the first PCB board based on the first actual coordinates and the first theoretical coordinates to obtain the deviation information comprises: obtaining a coordinate translation deviation of the testing machine relative to the first PCB board based on the first actual coordinates and the corresponding first theoretical coordinates of the same reference point; constructing a first reference line and a second reference line formed by the at least two reference points based on the first actual coordinates and the first theoretical coordinates, respectively, and analyzing a rotation angle between the first reference line and the second reference line to obtain a coordinate rotation deviation of the testing machine relative to the first PCB board; taking the coordinate translation deviation and the coordinate rotation deviation as the deviation information.

6. The PCB board alignment method of claim 1, wherein, The performing of the motion compensation on the motion mechanism of the testing machine based on the deviation information to realize the alignment of the first PCB board comprises: obtaining the actual distance between the at least two reference points based on the first actual coordinates of the at least two reference points; obtaining the theoretical distance between the at least two reference points based on the first theoretical coordinates of the at least two reference points; obtaining a size correction coefficient of the first PCB board based on the ratio of the actual distance and the theoretical distance; performing motion compensation on a motion mechanism of the test machine based on the deviation information and the size correction coefficient, so as to realize alignment of the first PCB board.

7. The PCB board alignment method of claim 1, wherein, The alignment information further comprises second theoretical coordinates of test points in the first PCB board; and the method further comprises: controlling a probe of the test machine to move to the second theoretical coordinates of a first test point among the test points; acquiring an image of the probe, and identifying coordinates of the probe in the test machine based on the image of the probe, to obtain a center point coordinate of the probe; if a coordinate deviation between the center point coordinate and the second theoretical coordinates of the first test point is greater than a preset deviation threshold, correcting coordinates of the first test point in the test machine.

8. The PCB board alignment method of claim 7, wherein, The correcting of the coordinates of the first test point in the test machine comprises: determining a second test point within a preset range of the first test point; analyzing an offset condition of the first test point relative to the at least two reference points to obtain a first offset condition; analyzing an offset condition of the second test point relative to the at least two reference points to obtain a second offset condition; determining a deformation condition of the first PCB board within the preset range based on the first offset condition and the second offset condition; if the first PCB board deforms within the preset range, correcting the coordinates of the first test point in the test machine.

9. The PCB board alignment method of claim 7, wherein, The method further comprises: if the coordinate deviation between the center point coordinate and the second theoretical coordinates of the first test point is less than or equal to the preset deviation threshold, obtaining a model of the first PCB board; realizing alignment of a second PCB board of the same model based on the model and the deviation information.

10. A testing machine characterized by, comprises: a test machine body comprising a probe, a vision module and a motion mechanism; a control device configured to execute the PCB board alignment method of any one of claims 1 to 9.

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