A PCB inner layer detection method, a detection device and a detection equipment

Abstract

This invention relates to a method, device, and equipment for detecting the inner layers of a PCB board. The method includes: acquiring the parameters of the first hole, determining the distance between adjacent holes, segmented movement control, and iterative iteration. After acquiring the reference target parameters of the first hole, the method compares the positional distances of adjacent vias to determine whether the adjacent holes meet the preset spacing requirements. Based on the determination results, segmented movement detection is then performed. After each detection is completed, the reference target parameters are updated, and the detection steps are executed iteratively to achieve automated and accurate detection of the inner layers of the PCB board. This method shortens the detection time and improves the efficiency of batch detection while ensuring probe safety and measurement accuracy.

Description

Technical Field

[0001] This invention relates to the field of PCB board detection technology, and in particular to a method, device and equipment for detecting the inner layers of a PCB board. Background Technology

[0002] The thickness of the inner copper layers and the interlayer distance of a PCB are core indicators for judging the quality, electrical performance, and reliability of the PCB. In PCB manufacturing, high-precision probing equipment is needed to automate the measurement of the inner copper layers in batches of vias. Currently, the industry mainstream adopts non-contact probe inner layer probing technology, which involves inserting a probe into the via of the PCB to detect the vertical distance between the target inner copper layer and the surface of the via, thereby calculating the board thickness, copper layer position, and interlayer parameters.

[0003] Existing measurement solutions have significant technical flaws: PCB boards commonly exhibit warping and micro-deformation during production and processing, resulting in poor consistency in overall board thickness and height. To avoid hard collisions between the probe and deformed board material, which could lead to probe breakage, wear, and measurement misalignment, existing equipment typically uses the following control logic: after measuring each hole, the probe is raised to a safe height before being moved to the next hole. Furthermore, each measurement requires the probe to fully exit the hole to complete full-stroke calibration. While this method effectively protects the probe and avoids measurement failures caused by deformed board material, it significantly sacrifices measurement efficiency. For batch PCB board and high-density hole array inspection scenarios, the frequent probe raising and full-stroke entry / exit actions are extremely time-consuming, resulting in long cycle times and low throughput, failing to meet the current production demands for high-precision, high-efficiency batch PCB inspection. Summary of the Invention

[0004] This invention aims to solve the problem of low detection efficiency in existing PCB inner layer detection technology. By combining adjacent hole spacing classification and segmented height control with different travel detection modes, the detection action time is shortened and the batch detection efficiency is improved while ensuring probe safety and measurement accuracy.

[0005] To achieve the objectives of this invention, the embodiments of this invention adopt the following technical solutions:

[0006] A method for probing the inner layers of a PCB board, comprising:

[0007] Obtain the first hole parameters: The probe enters the first hole to be tested and obtains the reference target parameters;

[0008] Adjacent Hole Distance Determination: Obtain the straight-line distance between the currently measured hole and the next hole to be measured, and compare the straight-line distance with a preset distance threshold.

[0009] If the straight-line distance does not exceed the preset distance threshold, the next hole to be tested is classified as a near-distance hole;

[0010] If the straight-line distance exceeds the preset distance threshold, the next hole to be tested will be classified as a long-distance hole.

[0011] Segmented movement control:

[0012] When the next hole to be tested is a near-distance hole, the probe is controlled to rise to a low safe height and move to the next hole to be tested for detection. After the detection is completed, the reference target parameters are updated.

[0013] When the next test hole is a long-distance hole, control the probe to be raised to a preset high safety height and move to the next test hole, and re-execute the step of obtaining the first hole parameters to update the reference target parameters;

[0014] Iterative loop: Based on the updated benchmark target parameters, repeat the adjacent hole distance determination and segmented movement control steps until all holes to be tested are detected.

[0015] In some embodiments, in the step of obtaining the first hole parameters, the probe is controlled to enter the first hole to be tested in a full-stroke detection mode. When the hole to be tested is a close-range hole, a fast detection mode is executed. In the full-stroke detection mode, the probe's detection movement distance is greater than that in the fast detection mode.

[0016] In some embodiments, when the probe performs a full-stroke detection mode, the probe travels through the first hole; when the probe performs a fast detection mode, the probe travels to the target layer.

[0017] In some embodiments, the target layer prediction position of the hole to be tested is calculated based on the reference target parameters and preset parameters of the measured hole. When the fast detection mode is executed, the probe moves to the target layer prediction position.

[0018] In some embodiments, the reference target parameter includes the actual plate thickness, the preset parameter includes the theoretical plate thickness, the deformation compression ratio is calculated based on the ratio of the actual plate thickness to the theoretical plate thickness, the theoretical target layer depth of the hole to be tested is corrected according to the deformation compression ratio, and the predicted target layer position of the hole to be tested is generated.

[0019] In some embodiments, the reference target parameter includes the actual position of the target layer, the preset parameter includes a compensation value, and the predicted position of the target layer of the hole to be tested is the sum of the actual position parameter of the target layer of the hole already tested and the compensation value.

[0020] In some embodiments, the reference target parameters include the in-hole height, actual board thickness, and actual position of the target layer, and the low-level safety height is determined based on the in-hole height of the most recently measured hole.

[0021] In some embodiments, before the step of obtaining the first hole parameters, a data loading step is also included, which imports the planar coordinates of all holes on the PCB board to be detected, the theoretical position of the inner copper layer, the preset distance threshold, the low-level safety height, and the high-level safety height.

[0022] A detection device, comprising

[0023] The probe module is used to perform probing actions and collect parameters;

[0024] A drive module is used to drive the probe to move in the vertical and horizontal directions;

[0025] The storage module is used to store preset distance thresholds, low-level safety height values, high-level safety height values, and PCB board parameters.

[0026] The processing module is communicatively connected to the probe module, the driver module, and the storage module, respectively. The processing module is configured as follows:

[0027] Implement probe detection control methods.

[0028] A testing device, comprising:

[0029] The testing equipment is used to support the PCB board to be tested.

[0030] Probe detection device.

[0031] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described PCB inner layer detection method.

[0032] The present invention has the following main advantages:

[0033] This invention categorizes holes to be tested into near-distance and far-distance holes based on adjacent hole distance. It employs a segmented lifting height control strategy for different categories and combines full-stroke detection and rapid detection modes. While ensuring probe safety and avoiding collisions that could deform the board surface, it significantly reduces the time spent on probe movement between holes and detection within holes, thereby greatly improving the overall efficiency of inner-layer probing for batch PCBs. Furthermore, based on the baseline target parameters of the already tested holes, the target layer position of subsequent holes to be tested is predicted and corrected, effectively compensating for positional deviations caused by board deformation and further ensuring detection accuracy. Other advantages of this invention are described in specific embodiments. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a PCB board inner layer detection method provided in an embodiment of the present invention.

[0036] Figure 2 This is a flowchart of a PCB board inner layer detection method provided by an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the PCB board under test provided in an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the full-stroke detection mode during the first hole detection provided in the embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the fast detection mode provided in the embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0041] In this embodiment, "several" and "more than" refer to two or more. In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] <Example 1>

[0044] like Figures 1 to 5 As shown in the figure, this embodiment provides a PCB inner layer detection method for batch inner layer copper layer parameter detection of PCBs, which can be implemented by combining with the probe system of existing detection equipment. Multiple test holes are distributed on the PCB to be tested, each with corresponding hole position planar coordinates. The probe enters the test holes sequentially according to a predetermined hole position order and performs detection within the holes. Existing technologies use a uniform action logic of "lifting to a higher position - translation - full-stroke entry - full-stroke exit" for all holes, without differentiated adaptation. The invalid stroke of a large number of holes occupies most of the detection time, resulting in a significant shortcoming in batch detection efficiency.

[0045] The PCB inner layer detection method in this embodiment includes the following steps:

[0046] S1 Obtain First Hole Parameters: The probe enters the first hole to be tested and obtains the reference target parameters. The first hole to be tested is the hole position selected first at the start of the current detection task. It can be the first hole obtained by sorting the hole position coordinates, a reference hole pre-specified by the detection program, or the hole position closest to the probe at the start of the detection task. The difference between the first hole to be tested and ordinary holes to be tested is that the first hole to be tested is used to establish the reference target parameters required for subsequent hole position detection, rather than just to output an independent detection result. The reference target parameters can reflect information such as the probe's entry height into the hole, the actual thickness of the PCB board, and the actual position of the target layer. The detection stroke, layer positioning, and movement height of subsequent holes can be determined using these reference target parameters. After the first hole parameters are formed, the first hole to be tested is recorded as the currently tested hole. The currently tested hole is not limited to the first hole to be tested at the start of the detection task. During the iterative process, the hole that has most recently completed detection and formed valid parameters can be used as the currently tested hole. When a new hole to be tested completes detection, the identifier of the currently tested hole can be updated, and the reference target parameters can be updated according to the detection parameters of that hole. In this way, the currently measured hole always corresponds to the hole position that has been detected in the current detection sequence and can provide a reference for the next hole movement.

[0047] S2 Neighbor Distance Determination: Obtain the straight-line distance between the currently measured hole and the next hole to be measured, and compare the straight-line distance with a preset distance threshold; if the straight-line distance does not exceed the preset distance threshold, the next hole to be measured is classified as a near-distance hole; if the straight-line distance exceeds the preset distance threshold, the next hole to be measured is classified as a far-distance hole.

[0048] After the current hole has been detected, the next hole to be detected is retrieved from the queue of holes to be detected, and the planar coordinates of the current hole and the next hole to be detected are read. The next hole to be detected can be the hole closest to the current hole. The straight-line distance is the linear interval between the planar coordinates of the two holes, used to reflect the horizontal movement span of the probe when moving from the current hole to the next hole to be detected. If the planar coordinates of the current hole are the first coordinates and the planar coordinates of the next hole to be detected are the second coordinates, the difference between the two coordinates in the horizontal direction is used to calculate the straight-line distance corresponding to the current transfer path. This straight-line distance is used to classify the movement path, not to change the detection order of the holes themselves. A preset distance threshold is set before the detection begins. This threshold is used to distinguish between near and far holes, and its value can be set according to the hole layout of the PCB board and the motion characteristics of the machine. The straight-line distance between the current hole and the next hole to be detected is compared with the preset distance threshold. When the straight-line distance does not exceed the preset distance threshold, the next hole to be detected is classified as a near hole. When the straight-line distance exceeds a preset distance threshold, the processing module classifies the next hole to be tested as a long-distance hole. The comparison result only affects the current transfer path and does not change the hole position attribute itself, nor does it require all holes to be fixedly classified into the same category at the start of detection. The same hole position may correspond to different transfer distance judgment results under different detection sequences or different currently measured hole conditions.

[0049] S3 segmented motion control:

[0050] When the next hole to be tested is a near-distance hole, the probe is controlled to rise to a low safety height and then moved to the next hole for testing. For near-distance holes, the probe is first controlled to rise vertically to a low safety height, and then moved horizontally to the next hole. The low safety height is the height at which the probe can complete a horizontal transfer near the board surface after leaving the current hole's detection position. This height should allow the probe to leave the current hole's detection position while providing necessary clearance for the probe to move from the current hole to the next hole. In the prior art, to prevent probe breakage, a relatively large safety insertion height must be reserved, which cannot achieve precise insertion into holes at short distances, and cannot compress the detection stroke or increase the speed while ensuring probe safety.

[0051] In this embodiment, the low-level safety height can be determined based on the entry height of the most recently measured hole, or an imported low-level safety height value can be directly used. The low-level safety height does not need to be the same across all hole positions; the specific height can vary according to the reference parameters of the most recently measured hole. After the probe reaches the low-level safety height, it moves horizontally according to the hole position plane coordinates of the next hole to be measured, stopping after reaching the corresponding hole position. Subsequently, the probe is controlled to enter the next hole to be measured from the low-level safety height to perform the detection action for that hole. After detection is completed, the hole is marked as the new currently measured hole, and the reference target parameters are updated.

[0052] In existing measurement methods, the probe must be fully inserted through the hole to complete the detection for each measurement. Even for conventional holes that do not require full-stroke detection, the probe still needs to complete the full stroke, which not only reduces the speed but also increases the mechanical wear and tear on the probe and increases equipment maintenance costs.

[0053] When the next hole to be tested is a long-distance hole, the probe is controlled to rise to a pre-set high safety height and move to the next hole to be tested. The step of obtaining the first hole parameters is then repeated to update the reference target parameters. For long-distance holes, the probe is first controlled to rise vertically to a pre-set high safety height, and then controlled to move horizontally to the next hole to be tested. The high safety height is used to increase the distance between the probe and the PCB board under a large horizontal span, reducing the possibility of interference between the probe, board surface, hole edge, or other detection parts. The high safety height can be a fixed control parameter loaded before the detection task begins. The high safety height and low safety height correspond to different transfer conditions. The low safety height is used for the transfer of near-distance holes, and the high safety height is used for the transfer of long-distance holes. The two can have different height values, with the value of the high safety height being greater than that of the low safety height, but this embodiment does not limit the specific difference between the two. For long-distance holes, the vertical lifting action and the horizontal transfer action are sequential; the corresponding horizontal transfer is only performed after the probe reaches the high safety height.

[0054] After the long-distance transfer is completed, instead of directly using the baseline target parameters from before the long-distance transfer to perform the next round of all hole detection, the step of acquiring the first hole parameters is repeated after the probe reaches the next hole to be tested. This re-execution means establishing the next hole to be tested as a new baseline, controlling the probe to enter that hole, and acquiring the corresponding baseline target parameters. Re-establishing the baseline after the long-distance transfer allows the new detection stage to obtain parameters corresponding to the current position. The actual board thickness, target layer position, or via height may differ at different locations on the PCB board; the new baseline parameters after the long-distance transfer can reflect the local detection status of that stage. Therefore, subsequent near-distance holes do not need to continue relying on the baseline target parameters from before the long-distance transfer for complete positioning, thus making the predicted position used for rapid detection closer to the parameter state of the current detection area.

[0055] S4 Iterative Loop: Based on the updated benchmark target parameters, the adjacent hole distance determination and segmented movement control steps are repeatedly executed until all holes to be tested are detected. After the current hole to be tested is detected, the processing module checks whether there are still undetected holes in the hole queue. If there are undetected holes, the next hole is reassigned as the next hole to be tested, the new planar coordinates of the currently detected hole and the next hole to be tested are read, and the adjacent hole distance determination is repeated. If the new straight-line distance does not exceed the preset distance threshold, a low-position safety height transfer is performed; if the new straight-line distance exceeds the preset distance threshold, a high-position safety height transfer is performed, and the first hole parameters are reacquired upon arrival. If the hole queue is empty, the iterative loop ends, and the detection status of all holes is saved.

[0056] In a continuous hole detection variation, the queue of holes to be tested is generated according to a horizontal arrangement, a vertical arrangement, or a predetermined scanning path. The processing module does not require the next hole to be tested to be the geometrically closest hole; instead, it determines the distance to the next hole actually selected in the current detection sequence. Therefore, the hole sorting method and the distance classification mechanism are independent of each other: the sorting mechanism is responsible for determining the detection order, and the distance determination is responsible for determining the transfer height under that order. For the same PCB board, different hole orderings can be used for different detection tasks without changing the control logic for near and far holes.

[0057] This method determines the planar distance between the currently measured hole and the next hole to be measured. For closely spaced adjacent holes, a low-position height transfer is used, eliminating the need to raise the probe to the original safe height each time. This shortens the average detection time for a single hole, significantly improving the overall detection efficiency in high-density hole array batch detection scenarios while still ensuring probe movement safety and avoiding probe collision damage caused by deformed board material. For holes requiring long-distance transfer, the steps of high-position lifting and re-acquiring reference parameters are retained, taking into account parameter differences caused by deformation in different areas of the PCB board. This improves efficiency while ensuring detection accuracy. No modification to the existing equipment hardware structure is required; the modification can be implemented simply by optimizing the motion control logic, resulting in low modification cost and strong adaptability.

[0058] Preferably, in the step of obtaining the first hole parameters, the probe is controlled to enter the first hole to be tested in a full-stroke detection mode. When the hole to be tested is a close-range hole, a fast detection mode is executed. In the full-stroke detection mode, the probe's detection movement distance is greater than that in the fast detection mode. The full-stroke detection mode refers to the probe moving a larger detection distance along the detection direction of the hole to obtain the layer information required to form a reference within the first hole to be tested. After entering the first hole to be tested, the probe is driven to move in a predetermined detection direction, and the probe's stroke penetrates the first hole, meaning the effective detection process of the probe covers the plate thickness direction of the first hole or passes through the detection range corresponding to the first hole. During the movement, the probe module collects layer response data, identifies the actual position of the target layer based on the collection results, and obtains reference target parameters such as the actual plate thickness and the hole height for subsequent calculations.

[0059] In full-stroke detection mode, the probe travels a greater distance than in rapid detection mode. The probe travels vertically downwards from above the hole to be tested, typically referred to as the Z-axis travel. The primary function of full-stroke detection mode is to establish a baseline, not to shorten the detection process for a single hole. Rapid detection mode, on the other hand, utilizes existing baseline parameters to position the probe at the predicted location in the target layer. The first hole to be tested uses full-stroke detection mode when no existing baseline is available. Subsequent holes identified as nearby can use rapid detection mode. For distant holes, the probe re-acquires the parameters of the first hole after moving to the next hole to be tested. This next hole can still use full-stroke detection mode during the establishment of a new baseline.

[0060] Before the full-stroke detection begins, the planar coordinates of the first hole to be tested, the theoretical position of the inner copper layer, and the theoretical parameters of the PCB board can be read. After the probe completes horizontal positioning, it enters the first hole to be tested vertically. As the probe moves vertically, the probe module continuously or according to a predetermined sampling method collects layer responses and associates the collected parameters with the probe's current position. When the probe executes the fast detection mode, it first calculates the predicted position of the target layer based on the reference target parameters. The probe only moves from a low safe height to the vicinity of the predicted position to complete the detection and acquisition, without needing to scan the entire hole depth, significantly shortening the movement distance and time of single-hole detection. The response data collected during the detection process only needs to be matched and identified around the predicted position. After the matching is completed, the movement can stop and the detection result can be output. It is not necessary to continue moving downwards to the bottom of the hole, effectively reducing the invalid movement of the probe and further compressing the detection time of a single hole. In batch detection scenarios, it can accumulate significant efficiency improvements.

[0061] In this embodiment, when the probe performs full-stroke detection mode, the probe travels through the first hole; when the probe performs fast detection mode, the probe travels to the target layer. The target layer is the copper layer inside the hole from which detection data is to be acquired, typically the target detection layer of the inner copper layer. Acquiring the parameter data of this target layer yields the inner layer detection result corresponding to the hole position, eliminating the need for further downward detection. Specifically, the predicted position of the target layer of the hole to be tested is calculated based on the baseline target parameters and preset parameters of the already tested holes. When performing fast detection mode, the probe moves to the predicted position of the target layer and stops moving only after completing the detection and acquisition at the predicted position, without needing to move further down to the bottom of the hole. Combined with motion optimization for low-position safety height transfer, the entire process from transfer to detection of near-distance holes is simplified, and ineffective movements are significantly reduced, which can significantly improve the overall speed of inner layer detection of batch PCB boards without changing the hardware structure. Meanwhile, since the near-distance hole relies on the updated current measured hole reference to obtain the target layer prediction position, the reference parameters are updated once after each hole detection is completed. This can adapt to local thickness or layer deviations of the PCB board, ensuring the detection accuracy of each hole and preventing accuracy loss due to compression stroke.

[0062] In this embodiment, the predicted location of the target layer is obtained in the following two ways:

[0063] As one implementation method, the reference target parameters include the actual board thickness, and the preset parameters include the theoretical board thickness. Based on the ratio of the actual board thickness to the theoretical board thickness, the deformation compression ratio is calculated. The theoretical target layer depth of the hole to be tested is then corrected according to the deformation compression ratio to generate the predicted target layer position of the hole. In actual production, the PCB board is affected by factors such as lamination processes and material shrinkage, resulting in a deviation between the overall board thickness and the theoretical board thickness designed in the design stage. PCB board warping is a local deformation characteristic, and there are differences in board thickness and board surface height in different areas of the same board material. However, existing technologies use uniform detection parameters for the entire board, failing to utilize the consistent thickness characteristics of local areas of the board material, resulting in poor parameter adaptability. In this embodiment, the deformation compression ratio is calculated using the actual board thickness obtained from the currently measured hole, allowing for a proportional correction of the theoretical target layer depth of subsequent holes to be tested. This makes the corrected predicted target layer position more closely match the actual production state of the current area, further improving positioning accuracy. The deformation compression ratio reflects the thickness change relationship of the PCB board under test relative to the theoretical board thickness under actual detection conditions. If the actual plate thickness and the theoretical plate thickness are expressed as the corresponding measured value and theoretical value, respectively, the deformation compression ratio can be calculated according to the ratio relationship: K=T a / T t Where K represents the deformation compression ratio, and T... a T represents the actual plate thickness. tThis represents the theoretical plate thickness. After obtaining this ratio, the theoretical target layer depth of the hole to be tested is corrected according to the deformation compression ratio to generate the predicted target layer position of the hole. In this calculation process, the actual plate thickness comes from the reference target parameters formed by the measured holes, and the theoretical plate thickness comes from preset parameters. The predicted depth corrected by the deformation compression ratio can be expressed as: D p =K*D t , where D p D represents the predicted depth corresponding to the predicted location of the target layer in the borehole to be measured. t This indicates the theoretical target layer depth of the borehole to be tested.

[0064] In another implementation, the reference target parameters include the actual position of the target layer, the preset parameters include a compensation value, and the predicted target layer position of the borehole to be tested is the sum of the actual target layer position parameters of the previously tested boreholes and the compensation value. This method utilizes the characteristic of smooth deviations in the actual target layer positions of adjacent local regions, directly superimposing the preset compensation value on the actual target layer position of the previous tested borehole to obtain the predicted target layer position of the next nearby borehole. The calculation method is simpler, consumes less computing resources in the processing module, and can improve the computational response speed while ensuring prediction accuracy. The compensation value is used to reflect the difference in target layer position between the currently tested borehole and the borehole to be tested. It can be directly provided by the preset parameters or read according to the established borehole position correspondence. Obtain the actual target layer position parameters of the tested boreholes and add these parameters to the compensation value to obtain the predicted target layer position of the borehole to be tested. This calculation relationship can be expressed as: P p =P a +△P, where P p P represents the predicted location of the target layer of the borehole to be tested. a This indicates the actual position parameters of the target layer in the measured borehole, and △P represents the compensation value.

[0065] The two target layer prediction methods described above can be used for different reference data conditions. The first method uses the ratio between the actual plate thickness and the theoretical plate thickness as the correction basis, and is suitable for situations where the target layer depth is estimated based on plate thickness variations. The second method uses the actual position of the target layer of the measured hole and the compensation value as the basis, and is suitable for situations where the actual position of the target layer has been obtained and the inter-hole compensation relationship can be determined. One of the prediction methods can be selected according to the parameter status in the storage module. Those skilled in the art will understand that the above are only two feasible methods for calculating the target layer prediction position, and other existing calculation methods can also be used to obtain the target layer prediction position, which is not limited in this application. The target layer prediction position is the positioning result calculated from existing parameters and is not equivalent to the final actual position that has not been detected and confirmed. After the probe reaches the target layer prediction position, target layer detection is still performed. The actual detection result is used to confirm the actual position of the target layer. Usually, the depth of the target layer prediction position is greater than the theoretical position, thereby ensuring that the probe can pass through the target layer. Predictive positioning and target layer confirmation play the roles of pre-positioning and detection confirmation in the control flow, respectively. If there is a difference between the confirmed actual position of the target layer and the target layer prediction position, the difference can be saved, and the actual position of the current hole can be used for subsequent reference recording.

[0066] In this embodiment, the reference target parameters include the inlet height, actual plate thickness, and actual target layer position. The low-level safety height is determined based on the inlet height of the most recently measured hole, where the inlet height is the height of the currently measured hole opening. The low-level safety height is higher than the inlet height by a fixed lifting distance. Using this method to determine the low-level safety height allows it to automatically adjust with the current plate height, preventing collisions during probe transfer caused by localized plate warping, thus further improving movement safety. The lifting distance can be preset according to the machine's accuracy and the plate warping range, minimizing the lifting height while meeting clearance requirements and preserving the efficiency advantage of close-range transfer. The actual plate thickness is calculated based on the surface and bottom layer parameters collected during the full-stroke detection process, and the actual target layer position is also identified from the full-stroke detection data. These three parameters together serve as the reference parameters for the current detection area, providing a basis for subsequent close-range hole position correction and transfer height setting.

[0067] Before obtaining the parameters of the first hole, a data loading step is also included, which imports the planar coordinates of all holes on the PCB board to be inspected, the theoretical position of the inner copper layer, the preset distance threshold, the low safety height, and the high safety height. The planar coordinates of all holes are used to establish the queue of holes to be tested and to determine the horizontal positioning position of each hole. The theoretical position of the inner copper layer is used to provide a theoretical layer reference for the full-stroke detection of the first hole and subsequent target layer identification; the preset distance threshold is used for classifying near-distance and far-distance holes; the low safety height and the high safety height are used for near-distance horizontal transfer and far-distance horizontal transfer, respectively.

[0068] This embodiment utilizes the characteristic of continuous and gradual warping of PCB materials: the thickness, deformation degree, and copper layer position parameters of closely adjacent holes are basically the same, while holes that are far apart tend to cross deformation areas and have larger parameter differences. The overall system adopts a dynamic determination mode for adjacent hole distance without partitioning, without preset fixed detection areas, and dynamically switches the probe movement strategy and parameter reuse logic according to the distance between adjacent holes.

[0069]

Specific example

[0070] The following description will further illustrate this embodiment in conjunction with a specific application scenario. This embodiment takes the detection of through holes on a PCB board as an example. In other embodiments, the hole to be tested is not limited to a through hole.

[0071] S100 Data Loading: The testing equipment loads the control program, importing basic data such as the plane coordinates of all holes on the PCB to be tested and the theoretical position of the inner copper layer; the system presets the distance judgment threshold, the low-position safety height of the probe, and the high-position safety height, and various parameters can be flexibly adjusted according to the degree of board warping and the accuracy of the testing equipment.

[0072] S200 obtains the first borehole reference target parameters:

[0073] After the device is started, it performs a full-stroke detection mode on the first hole to be tested on the PCB board, such as... Figure 4 The image shown is a cross-sectional view of the first hole to be tested on the PCB board.

[0074] S210: Control the probe to rise to the preset high safety height and move it horizontally to directly above the first hole.

[0075] S220: The probe travels down the entire length of the via to be tested, sequentially completing the actions of entering the via, probing the target copper layer Z, and exiting the bottom of the via along path L1.

[0076] S230: Collect measured data, including actual hole height, actual board thickness, and actual position of the target copper layer; combine with the theoretical copper layer position in the drawings to calculate the deformation compression ratio = actual copper layer thickness ÷ theoretical copper layer thickness; store the actual hole height, actual board thickness, and deformation compression ratio as benchmark target parameters for subsequent hole position measurements.

[0077] S300 Adjacent Hole Spacing Calculation and Threshold Determination:

[0078] After the current hole position measurement is completed, the system retrieves the hole position coordinate data, automatically calculates the straight-line distance between the currently measured hole and the next hole to be measured, and compares it with the preset distance threshold. Holes that do not exceed the preset distance threshold are classified as close-distance holes (hole distance ≤ preset threshold), while holes that exceed the preset distance threshold are classified as far-distance holes (hole distance > preset threshold).

[0079] S400 Close-Range Hole Position Rapid Measurement:

[0080] like Figure 5 The image shown is a cross-sectional view of the closely spaced holes. It is determined that the two holes are in the same continuous deformation region, with no significant changes in plate thickness or warpage. Therefore, the rapid measurement logic is executed.

[0081] S410: The probe only rises slightly to the low safety height, and does not rise to the high safety height.

[0082] S420: The probe is kept in a low position and moved to the position above the next hole, i.e. the second hole to be tested, and the hole height in the current reference target parameters is directly reused.

[0083] S430: The predicted position of the target copper layer Z is obtained by multiplying the deformation compression ratio by the theoretical copper layer position of the hole to be tested.

[0084] S440: The measurement is completed when the probe descends along path L2 to the corrected target copper layer prediction position. There is no need to continue descending to the bottom of the hole, thus canceling the invalid exit stroke.

[0085] S450: After the measurement is completed, the benchmark target parameters are updated with the measured data of the current hole position to realize the parameter iteration hole by hole and adapt to the small continuous deformation of the plate.

[0086] S500 Remote Hole Safety Reset and Recalibration

[0087] After the detection of area A is completed, the next hole to be tested is hole 13, whose distance from the already tested holes in area A exceeds the threshold. When detecting holes at a distance, it is determined that the two holes cross different deformation areas, and the plate thickness and warpage parameters have large deviations, posing a risk of needle breakage. Therefore, the safety detection logic is executed.

[0088] S510: The probe is raised to a preset high safety height to avoid collision hazards caused by board deformation.

[0089] S520: The probe moves horizontally to the next test hole, i.e., test hole 13, while maintaining a high safety height.

[0090] S530: Re-execute the full-stroke detection mode for this hole location, collect new hole height, actual plate thickness, deformation compression ratio, and update the system's baseline target parameters.

[0091] S600 full-board cyclic measurement:

[0092] Repeat steps S300 to S500 to complete the adaptive measurement of all holes on the entire PCB board, one hole at a time, until all holes have been measured. That is, first complete the measurement of region A, then complete the measurement of region B, until all holes have been measured, forming the probe movement path S.

[0093] The PCB inner layer detection method in this embodiment has the following technical advantages:

[0094] 1. The near-distance aperture adopts a fast mode of low-position translation, parameter reuse, and compressed detection stroke; the far-distance aperture automatically switches to high-position translation and recalibrates, achieving a dynamic balance between probe protection and detection efficiency.

[0095] 2. The compression ratio is calculated by comparing the measured value with the theoretical value, and the copper layer detection position is dynamically corrected. The probe does not need to penetrate the bottom of the hole to complete the accurate measurement, completely eliminating the redundant action of exiting the hole throughout the entire stroke.

[0096] 3. It can achieve precise entry into the hole with an extremely small safety distance, while eliminating the need for full-stroke exit detection, thus minimizing the probe's travel distance and maximizing the detection speed while eliminating the risk of needle breakage.

[0097] <Example 2>

[0098] Compared to Embodiment 1, this embodiment provides a detection device for executing the aforementioned detection process. The probe detection device of this embodiment includes a probe module, a drive module, a storage module, and a processing module. The probe module performs detection actions and collects parameters. The drive module drives the probe to move vertically and horizontally. The storage module stores preset distance thresholds, low-level safety height values, high-level safety height values, and PCB board parameters. The processing module is communicatively connected to the probe module, drive module, and storage module. The processing module reads detection task parameters from the storage module, sends position control commands to the drive module, and receives detection parameters generated by the probe module, thereby achieving coordinated control of hole position transfer, hole detection, distance determination, and reference update.

[0099] The probe module can perform full-stroke detection after the probe enters the borehole to be tested, or it can perform rapid detection after obtaining the predicted position of the target layer. The parameters collected by the probe module are used to determine the parameters of the first borehole or the target layer detection result of the current borehole. The parameters generated by the probe module are transmitted to the processing module, which identifies and records the parameters. The probe module can also provide the processing module with the current probe detection status, enabling the processing module to distinguish whether the probe is in the state of external transfer, internal insertion, full-stroke detection, rapid detection, or detection completed.

[0100] The drive module includes a drive section for vertical movement and a drive section for horizontal movement. Vertical movement is used to move the probe into the hole to be tested, raise it from the hole to a low or high safety height, and move it from the safety height into the next hole to be tested. Horizontal movement is used to move the probe between the current hole position and the next hole to be tested. The processing module selects different movement control paths based on distance determination results: low safety height for nearby holes, and high safety height for distant holes. After receiving a control command, the drive module executes the corresponding movement and reports the movement completion status back to the processing module. The processing module triggers the next action after confirming the completion of the movement.

[0101] The storage module saves preset distance thresholds, low-level safety height values, high-level safety height values, hole position plane coordinates, and PCB board parameters. PCB board parameters include the theoretical position of the inner copper layer and the theoretical board thickness used for target layer prediction. The storage module can also save currently measured holes, the next hole to be measured, baseline target parameters, target layer prediction positions, and detection results, enabling the processing module to continuously call up data generated in the previous detection stage during iterative processing. The stored content is organized according to the detection task; hole position data and theoretical parameters for different PCB boards can be saved separately.

[0102] When the processing module performs distance determination, it reads the planar coordinates of the currently measured hole and the next hole to be measured from the storage module to obtain the straight-line distance between the two holes, and compares the straight-line distance with a preset distance threshold. After the classification result is formed, the processing module sends a low-order or high-order movement command to the drive module; if the classification result is a long-distance hole, the processing module calls the probe module to re-execute the acquisition of the first hole parameters after the horizontal transfer is completed, so as to update the baseline target parameters; if the classification result is a short-distance hole, the processing module can call the existing baseline target parameters for rapid detection. For the distance determination, segmented movement, rapid detection and parameter update process, please refer to the above sections on inter-hole distance diversion and segmented detection control, first hole full-stroke detection and target layer prediction and positioning, and detection initialization and short-distance transfer safety height.

[0103] <Example 3>

[0104] This embodiment provides a testing device, including a machine base and a probe testing device. The machine base is used to support the PCB board to be tested, and the probe testing device is installed, set, or arranged in the corresponding testing area of ​​the machine base. After the PCB board to be tested is placed in the testing area of ​​the machine base, the machine base provides a relatively stable spatial reference for the planar coordinates of the hole positions. The probe testing device controls the probe to perform horizontal positioning above the PCB board based on the hole position data, and then enters the corresponding hole to be tested vertically. The machine base and the probe testing device can cooperate through a control interface or the same control system; the specific connection method is not limited.

[0105] Before testing begins, the PCB board to be tested is located in the testing area of ​​the machine. The probe testing device reads the corresponding hole plane coordinates, the theoretical position of the inner copper layer, the preset distance threshold, and the low and high safety heights. The probe testing device completes the full-stroke detection of the first hole to be tested according to the aforementioned method, and selects either the low or high safety height for hole transfer based on the straight-line distance between holes. The machine provides a reference for the PCB board's support and testing, while the probe module, drive module, storage module, and processing module undertake the specific detection and control actions. For the module composition, communication relationships, and execution process of the probe testing device, please refer to the module collaboration section of the aforementioned probe testing device.

[0106] <Example 4>

[0107] This embodiment provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the aforementioned PCB board inner layer detection method, including data loading, obtaining first hole parameters, determining adjacent hole distances, segmented movement control, and iterative looping. The computer-readable storage medium can be any medium capable of storing the computer program and being read by a processor; the specific medium form is not limited. The functional instructions in the computer program establish the execution relationship between parameter reading, distance comparison, mode selection, and movement control according to the method steps. The computer-readable storage medium can be any tangible medium containing or storing a program, including but not limited to: USB flash drive, portable hard drive, read-only memory (ROM), random access memory (RAM), magnetic disk, or optical disk, etc.

[0108] In the above embodiments one to four, during the working process, depending on the different working environments, some of the technical implementation methods of embodiments one to four can be combined or replaced.

[0109] The technical principles of the present invention have been described above in conjunction with specific embodiments. However, it should be noted that these descriptions are merely for explaining the principles of the present invention and should not be construed as limiting the scope of protection of the present invention in any way. Based on this explanation, those skilled in the art can conceive of other specific embodiments or equivalent substitutions of the present invention without creative effort, and all such embodiments will fall within the scope of protection of the present invention.

Claims

1. A method for detecting the inner layers of a PCB board, characterized in that, include: Obtain the first hole parameters: The probe enters the first hole to be tested and obtains the reference target parameters; Adjacent Hole Distance Determination: Obtain the straight-line distance between the currently measured hole and the next hole to be measured, and compare the straight-line distance with a preset distance threshold. If the straight-line distance does not exceed the preset distance threshold, the next hole to be tested is classified as a near-distance hole; If the straight-line distance exceeds the preset distance threshold, the next hole to be tested will be classified as a long-distance hole. Segmented movement control: When the next hole to be tested is a near-distance hole, the probe is controlled to rise to a low safe height and move to the next hole to be tested for detection. After the detection is completed, the reference target parameters are updated. When the next test hole is a long-distance hole, control the probe to be raised to a preset high safety height and move to the next test hole, and re-execute the step of obtaining the first hole parameters to update the reference target parameters; Iterative loop: Based on the updated benchmark target parameters, repeat the adjacent hole distance determination and segmented movement control steps until all holes to be tested are detected.

2. The PCB board inner layer detection method according to claim 1, characterized in that, In the step of obtaining the first hole parameters, the probe is controlled to enter the first hole to be tested in full-stroke detection mode. When the hole to be tested is a close-range hole, a fast detection mode is executed. In the full-stroke detection mode, the probe's detection movement distance is greater than that in the fast detection mode.

3. The PCB board inner layer detection method according to claim 2, characterized in that, When the probe is in full-stroke detection mode, the probe travels through the first hole; when the probe is in fast detection mode, the probe travels to the target layer.

4. The PCB board inner layer detection method according to claim 3, characterized in that, The target layer prediction position of the hole to be tested is calculated based on the reference target parameters and preset parameters of the measured hole. When the fast detection mode is executed, the probe moves to the target layer prediction position.

5. The PCB board inner layer detection method according to claim 4, characterized in that, The reference target parameters include the actual plate thickness, and the preset parameters include the theoretical plate thickness. Based on the ratio of the actual plate thickness to the theoretical plate thickness, the deformation compression ratio is calculated. The theoretical target layer depth of the hole to be tested is corrected according to the deformation compression ratio to generate the predicted target layer position of the hole to be tested.

6. The PCB board inner layer detection method according to claim 4, characterized in that, The reference target parameters include the actual position of the target layer, the preset parameters include compensation values, and the predicted position of the target layer of the hole to be tested is the sum of the actual position parameters of the target layer of the tested hole and the compensation values.

7. The PCB board inner layer detection method according to claim 1, characterized in that, The benchmark target parameters include the in-hole height, actual plate thickness, and actual position of the target layer. The low-level safety height is determined based on the in-hole height of the most recently measured hole.

8. The PCB board inner layer detection method according to claim 1, characterized in that, Before the step of obtaining the first hole parameters, a data loading step is also included, which imports the planar coordinates of all holes on the PCB board to be tested, the theoretical position of the inner copper layer, the preset distance threshold, the low-level safety height, and the high-level safety height.

9. A detection device, characterized in that, include The probe module is used to perform probing actions and collect parameters; A drive module is used to drive the probe to move in the vertical and horizontal directions; The storage module is used to store preset distance thresholds, low-level safety height values, high-level safety height values, and PCB board parameters. The processing module is communicatively connected to the probe module, the driver module, and the storage module, respectively. The processing module is configured as follows: Perform the probe detection control method as described in any one of claims 1 to 8.

10. A testing device, characterized in that, include: The testing equipment is used to support the PCB board to be tested. The probe detection device as described in claim 9.

11. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1 to 8.

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