A circuit board aperture detection system and method

Abstract

This invention discloses a hole diameter detection system and method for circuit boards, relating to the field of small hole detection on circuit boards. It includes a three-degree-of-freedom conveying mechanism and a detection worktable. The detection worktable is arranged within the working range of the three-degree-of-freedom conveying mechanism. A small diameter detection component is installed on the detection worktable, comprising a high-precision detection cone and a high-precision distance sensor. The high-precision detection cone is vertically mounted on the top surface of the detection worktable and is formed by a frustum of a cone, with its small-diameter end positioned away from the detection worktable. The high-precision distance sensor is mounted on the top surface of the detection worktable, with its detection path vertically upwards. A horizontal feeding mechanism is installed on the three-degree-of-freedom conveying mechanism. Utilizing the linear axial change in the diameter of the high-precision detection cone, combined with the high-precision distance sensor for accurate detection of the circuit board height, the inner diameter can be directly calculated from the contact position of the small hole on the cone.

Description

Technical Field

[0001] This invention relates to the field of circuit board hole detection, specifically to a circuit board hole diameter detection system and method. Background Technology

[0002] In the electronics manufacturing industry, circuit boards are core components of electronic devices, and their processing precision directly affects the overall performance of the device. Among them, the inner diameter of various small holes on the circuit board (such as vias and mounting holes) is a critical parameter. If the hole diameter deviation exceeds the allowable range, it may lead to difficulties in component assembly, poor signal transmission, or even short circuits. Therefore, high-precision detection of the inner diameter of small holes is an important part of the circuit board production process.

[0003] Traditional methods for inspecting circuit board hole diameters are mainly divided into two categories: manual inspection and automated inspection. Manual inspection relies on tools such as calipers and plug gauges, and operators visually inspect or manually measure to determine whether the hole diameter is up to standard. This method is not only inefficient and difficult to adapt to the needs of mass production, but also its inspection accuracy is greatly affected by human factors and is prone to misjudgment.

[0004] In automated inspection methods, optical inspection is commonly used. Optical inspection uses a camera to capture images of small holes and calculates the aperture using image processing algorithms. However, due to limitations in the resolution of the optical system and interference from factors such as reflections from the inner wall of the hole and oil stains, the detection accuracy for tiny apertures (such as those with a diameter less than 1 cm) is often insufficient. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a circuit board aperture detection system and detection method to solve the deficiencies of the prior art.

[0006] The objective of this invention is achieved through the following technical solution: a circuit board aperture detection system, comprising a three-degree-of-freedom conveying mechanism and a detection worktable. The detection worktable is arranged within the working range of the three-degree-of-freedom conveying mechanism. A small-diameter detection component is provided on the detection worktable, comprising a high-precision detection cone and a high-precision distance sensor. The high-precision detection cone is vertically mounted on the top surface of the detection worktable, and is formed by a frustum of a cone, with its small-diameter end positioned away from the detection worktable. The high-precision distance sensor is mounted on the top surface of the detection worktable, with its detection path vertically upward. A horizontal feeding mechanism is installed on the three-degree-of-freedom conveying mechanism. The three-free conveying mechanism is used to drive the horizontal feeding mechanism to move along the X, Y, and Z axes in the spatial coordinate system. The horizontal feeding mechanism includes a base plate, a rectangular feeding plate frame, and a feeding tray. The feeding tray is arranged in the inner circle of the rectangular feeding plate frame. The bottom of the rectangular feeding plate frame has several first negative pressure holes. The top of the rectangular feeding plate frame is connected to a side sliding rod. The bottom of the feeding tray has several second negative pressure holes. The top of the feeding tray is connected to a central sliding rod. The central sliding rod and the side sliding rod are both slidably mounted on the base plate. The central sliding rod and the side sliding rod both have a degree of freedom to move in the vertical direction. The feeding tray and the rectangular feeding plate frame are arranged alternately in the vertical direction, so that the circuit board is fed only through the feeding tray or the rectangular feeding plate frame at a time.

[0007] Furthermore, the side slide rod includes a large-diameter rod and a small-diameter rod. The large-diameter rod slides through the base plate, and a detection hole is opened at the bottom of the large-diameter rod along its own axial direction. One end of the small-diameter rod is slidably fitted in the detection hole, and the other end is connected to a rectangular feeding plate frame. A spring is sleeved on the small-diameter rod, and the two ends of the spring are respectively connected to the rectangular feeding plate frame and the large-diameter rod.

[0008] Furthermore, a position detection component is provided inside the detection hole. The position detection component includes a drive plate, a detection spring, a pressure plate, and a pressure sensor. The two ends of the detection spring are respectively connected to the drive plate and the pressure plate. The drive plate is connected to a small-diameter rod. The pressure sensor is installed on the inner top wall of the detection hole. The pressure plate contacts the pressure shaft of the pressure sensor. The structure of the middle slide rod is the same as that of the side slide rod.

[0009] Furthermore, the top end of the side slide rod passes through the base plate and is connected to a first rack, and the top end of the middle slide rod passes through the base plate and is connected to a second rack. The second rack is arranged opposite to the first rack. A switching reduction motor is mounted on the base plate, and the output shaft of the switching reduction motor is connected to a switching gear. The switching gear is located between the first rack and the second rack, and both the first rack and the second rack mesh with the switching gear.

[0010] Furthermore, the horizontal feeding mechanism also includes a top plate, a transverse micro-motion plate, and a longitudinal micro-motion plate. The top plate is mounted on a three-degree-of-freedom conveying mechanism. The transverse micro-motion plate is slidably mounted on the bottom of the top plate. The longitudinal micro-motion plate is slidably mounted on the bottom of the transverse micro-motion plate. A connecting rod is fixed to the top of the base plate. The connecting rod is fixedly connected to the longitudinal micro-motion plate. The moving direction of the transverse micro-motion plate is perpendicular to the moving direction of the longitudinal micro-motion plate on the horizontal plane.

[0011] Furthermore, the bottom of the top plate has two parallel horizontal inverted T-shaped grooves, and a horizontal inverted T-shaped block is slidably fitted in the horizontal inverted T-shaped groove. The horizontal inverted T-shaped block is fixedly connected to a horizontal micro-motion plate. A horizontal telescopic rod is provided in the horizontal inverted T-shaped groove. The two ends of the horizontal telescopic rod are respectively connected to the top plate and the horizontal inverted T-shaped block. A horizontal micro-motion spring is sleeved on the horizontal telescopic rod. The bottom of the horizontal micro-motion plate has two parallel vertical inverted T-shaped grooves, and the vertical inverted T-shaped grooves are perpendicular to the horizontal inverted T-shaped grooves. A vertical inverted T-shaped block is slidably fitted in the vertical inverted T-shaped groove. The vertical inverted T-shaped block is fixedly connected to a vertical micro-motion plate. A vertical telescopic rod is provided in the vertical inverted T-shaped groove. The two ends of the vertical telescopic rod are respectively connected to the horizontal micro-motion plate and the vertical inverted T-shaped block. A vertical micro-motion spring is sleeved on the vertical telescopic rod.

[0012] Furthermore, the three-degree-of-freedom conveying mechanism includes a lifting beam, a sliding crossbeam, and a sliding seat. Two lifting beams are arranged in parallel, and each lifting beam has a degree of freedom to move in the vertical direction. The two ends of the sliding crossbeam are slidably mounted on the two lifting beams respectively. The sliding seat is slidably mounted on the sliding crossbeam, and the direction of movement of the sliding crossbeam is perpendicular to the direction of movement of the sliding seat in the horizontal plane.

[0013] Furthermore, both ends of the lifting beam are vertically equipped with lifting cylinders, the telescopic shafts of the lifting cylinders are connected to the lifting beam, a first lead screw is rotatably mounted on the top of the lifting beam, a first lead screw nut slider is threaded onto the first lead screw, the first lead screw nut slider slides onto a first guide rail, the first guide rail is fixed on the lifting beam, two first lead screw nut sliders are respectively connected to both ends of the sliding crossbeam, a second lead screw is rotatably mounted on the top of the sliding crossbeam, a second lead screw nut slider is threaded onto the second lead screw, the second lead screw nut slider slides onto a second guide rail, the second guide rail is fixed on the sliding crossbeam, a sliding seat is mounted on the second lead screw nut slider, a first motor and a second motor are respectively mounted on the lifting beam and the sliding crossbeam, the output shaft of the first motor is driven and connected to the first lead screw, and the output shaft of the second motor is driven and connected to the second lead screw.

[0014] Furthermore, a threaded column is coaxially fixed to the large-diameter end of the high-precision detection cone rod, and a threaded hole is opened on the top of the detection worktable, with the threaded column threaded into the threaded hole.

[0015] A method for detecting the aperture of a circuit board, utilizing the aforementioned circuit board aperture detection system, includes the following steps:

[0016] S1. Select the feeding and adsorption area according to the position of the hole to be detected on the circuit board. If the hole is located in the middle of the circuit board, feed it through the rectangular feeding plate frame; if the hole is located around the circuit board, feed it through the feeding tray, so that the hole to be detected is completely exposed.

[0017] S2. After the circuit board is horizontally adsorbed and loaded, the circuit board is driven by the three-degree-of-freedom conveying mechanism to drive the corresponding high-precision detection cone rod.

[0018] S3. The circuit board moves downward, allowing the high-precision detection cone to pass through the small hole to be detected. When the diameter of the high-precision detection cone matches the diameter of the small hole to be detected, the circuit board can no longer move downward.

[0019] S4. The height of the circuit board is detected by a high-precision distance sensor, which reflects the position of the detection hole on the high-precision detection cone. The diameter of the high-precision detection cone changes linearly with its own axial height. The inner diameter of the detection hole can be obtained by using the high-precision detection cone with known dimensions, thus completing the inner diameter detection of the circuit board hole.

[0020] The beneficial effects of this invention are:

[0021] 1. The inner diameter of small holes on circuit boards is detected using a mechanical automatic detection method. The diameter of the high-precision detection cone changes linearly along the axial direction. Combined with the high-precision distance sensor for accurate detection of the height of the circuit board, the inner diameter can be directly calculated from the contact position of the small hole on the cone. This avoids the image interference and errors that affect the detection accuracy in optical detection, and the detection accuracy can meet the detection requirements of small holes (diameter less than 1mm). The results are highly stable, accurate, automated, and capable of batch detection.

[0022] 2. The three-degree-of-freedom conveying mechanism enables flexible movement and precise positioning of the circuit board in the X, Y, and Z directions. Combined with the rapid switching of the horizontal feeding mechanism, it can continuously inspect small holes at different positions on the circuit board without frequent equipment adjustments or tooling changes, significantly shortening the inspection cycle and meeting the high-efficiency inspection needs of mass production.

[0023] 3. The horizontal feeding mechanism, through the staggered arrangement and flexible switching of the rectangular feeding plate frame and the feeding tray, can select the appropriate feeding method according to the position of the hole on the circuit board, ensuring that the hole to be tested is completely exposed and avoiding obstruction by the feeding mechanism. It is suitable for hole testing on circuit boards with various layouts. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a circuit board aperture detection system according to the present invention. Figure 1 ;

[0025] Figure 2 This is a schematic diagram of the horizontal feeding mechanism in a circuit board aperture detection system according to the present invention. Figure 1 ;

[0026] Figure 3 This is a schematic diagram of the horizontal feeding mechanism in a circuit board aperture detection system according to the present invention. Figure 2 ;

[0027] Figure 4 This is a schematic diagram of the internal structure of the sliding probe in a circuit board aperture detection system according to the present invention;

[0028] Figure 5 This is a schematic diagram of the top plate structure in a circuit board aperture detection system according to the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of a transverse micro-motion plate in a circuit board aperture detection system according to the present invention;

[0030] Figure 7 This is a schematic diagram of the structure of a circuit board aperture detection system according to the present invention. Figure 2 ;

[0031] Figure 8 This is a schematic diagram of the internal structure of the detection workbench in a circuit board aperture detection system according to the present invention.

[0032] In the diagram, 1-Detection workbench, 2-High-precision detection cone rod, 3-High-precision distance sensor, 4-Base plate, 5-Rectangular feeding plate frame, 6-Feeding tray, 7-First negative pressure hole, 8-Side sliding rod, 9-Second negative pressure hole, 10-Middle sliding rod, 11-Large diameter rod, 12-Small diameter rod, 13-Detection hole, 14-Spring, 15-Drive plate, 16-Detection spring, 17-Pressure plate, 18-Pressure sensor, 19-First rack, 20-Second rack, 21-Switching reduction motor, 22-Switching gear, 23-Top plate, 24-Horizontal micro-motion plate, 25-Longitudinal micro-motion plate, 26-Connecting rod, 27-Horizontal inverted T-slot, 28-Horizontal inverted T-block, 29-Horizontal telescopic rod, 30-Horizontal micro-motion... Spring, 31-Longitudinal inverted T-block, 32-Longitudinal telescopic rod, 33-Longitudinal micro-motion spring, 34-Lifting beam, 35-Sliding crossbeam, 36-Sliding seat, 37-Lifting cylinder, 38-First lead screw, 39-First lead screw nut slider, 40-First guide rail, 41-Second lead screw, 42-Second lead screw nut slider, 43-Second guide rail, 44-First motor, 45-Second motor, 46-Threaded column, 47-Threaded hole, 48-Limiting rotating column, 49-Limiting pin, 50-Cavity, 51-Through hole, 52-Limiting column, 53-Rectangular limiting groove, 54-Limiting conical hole, 55-Large gear ring, 56-Self-locking motor, 57-Pinary gear, 58-Limiting cylinder, 59-Longitudinal inverted T-groove. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0034] Example 1

[0035] like Figures 1 to 8As shown, a circuit board aperture detection system includes a three-degree-of-freedom conveying mechanism and a detection worktable 1. The detection worktable 1 is arranged within the working range of the three-degree-of-freedom conveying mechanism. A small-diameter detection component is installed on the detection worktable 1, including a high-precision detection cone 2 and a high-precision distance sensor 3. The high-precision detection cone 2 is vertically mounted on the top surface of the detection worktable 1 and is formed by a frustum of a cone. The small-diameter end of the high-precision detection cone 2 is positioned away from the detection worktable 1. The high-precision distance sensor 3 is installed on the top surface of the detection worktable 1, and its detection path is vertically upward. A horizontal feeding mechanism is installed on the three-degree-of-freedom conveying mechanism, which is used to drive the horizontal feeding mechanism along the X-axis in the spatial coordinate system. The horizontal feeding mechanism, which allows movement along three axes (Y, Z), includes a substrate 4, a rectangular feeding plate frame 5, and a feeding tray 6. The feeding tray 6 is arranged in the inner circle of the rectangular feeding plate frame 5. The bottom of the rectangular feeding plate frame 5 has several first negative pressure holes 7, and the top of the rectangular feeding plate frame 5 is connected to a side sliding rod 8. The bottom of the feeding tray 6 has several second negative pressure holes 9, and the top of the feeding tray 6 is connected to a central sliding rod 10. Both the central sliding rod 10 and the side sliding rod 8 are slidably mounted on the substrate 4, and both have a degree of freedom to move vertically. The feeding tray 6 and the rectangular feeding plate frame 5 are staggered vertically, allowing the circuit board to be fed through either the feeding tray 6 or the rectangular feeding plate frame 5 at a time. Circuit boards requiring aperture inspection are stacked in the feeding box and fed through three axes. A horizontal feeding mechanism, driven by a conveyor, picks up circuit boards from the top of the feeding box. First, it switches between a rectangular feeding plate frame 5 and a feeding tray 6 based on the position of the small hole to be detected on the circuit board. Specifically, when the detection hole is located in the center of the circuit board, i.e., within the coverage area of ​​the feeding tray 6, the feeding tray 6 moves upward, and the rectangular feeding plate frame 5 moves downward, picking up the circuit board through the first negative pressure hole 7 of the rectangular feeding plate frame 5 for feeding detection. When the detection hole is located around the perimeter of the circuit board, i.e., within the coverage area of ​​the rectangular feeding plate frame 5, the feeding tray 6 moves downward, and the rectangular feeding plate frame 5 moves upward, picking up the circuit board through the second negative pressure hole 9 of the feeding tray 6 for feeding detection. This ensures that the small hole to be detected is completely exposed, avoiding obstruction by the feeding mechanism, and is suitable for various applications. The circuit board is designed for small hole detection. Then, based on the coordinate position of the hole to be detected on the circuit board, a three-degree-of-freedom conveying mechanism is planned to make the small hole to be detected on the circuit board directly above the high-precision detection cone 2. The circuit board is then moved downwards so that the high-precision detection cone 2 passes into the small hole to be detected. When the diameter of the high-precision detection cone 2 matches the diameter of the small hole to be detected, the circuit board can no longer move downwards. The height of the circuit board at this time is detected by the high-precision distance sensor 3, which reflects the position of the small hole on the high-precision detection cone 2. The diameter of the high-precision detection cone 2 changes linearly with its own axial height. The inner diameter of the small hole can be obtained by using the high-precision detection cone 2 with known dimensions, thus completing the inner diameter detection of the small hole on the circuit board.The specific detection principle is as follows: the high-precision distance sensor 3 detects the position of the bottom surface of the circuit board on the high-precision detection cone 2, thus dividing the high-precision detection cone 2 horizontally into upper and lower parts through the circuit board. Both parts form similar frustums of cones with the high-precision detection cone 2. Since the axial length, top diameter, and bottom diameter of the high-precision detection cone 2 are known, and the height of the circuit board on the high-precision detection cone 2 is obtained, the aperture of the small hole can be calculated according to the similarity theorem—corresponding sides are proportional. A mechanical automatic detection method is used to detect the inner diameter of the small hole on the circuit board, avoiding image interference and errors that affect detection accuracy in optical detection. This ensures that the detection accuracy meets the requirements for detecting micro-apertures (diameter less than 1mm), resulting in strong stability, high detection accuracy, high automation, and the ability to perform batch detection. In specific implementation, the high-precision distance sensor 3 uses a laser rangefinder sensor, which has high detection accuracy.

[0036] Example 2

[0037] Based on Example 1, such as Figures 1 to 7As shown, the three-degree-of-freedom conveying mechanism includes a lifting beam 34, a sliding crossbeam 35, and a sliding seat 36. Two lifting beams 34 are arranged in parallel, and each lifting beam 34 has a degree of freedom to move vertically. The two ends of the sliding crossbeam 35 are slidably mounted on the two lifting beams 34, respectively. The sliding seat 36 is slidably mounted on the sliding crossbeam 35. The direction of movement of the sliding crossbeam 35 is perpendicular to the direction of movement of the sliding seat 36 in the horizontal plane. Lifting cylinders 37 are vertically installed at both ends of the lifting beam 34. The telescopic shafts of the lifting cylinders 37 are connected to the lifting beam 34. A first lead screw 3 is rotatably mounted on the top of the lifting beam 34. 8. A first lead screw nut slider 39 is threaded onto the first lead screw 38. The first lead screw nut slider 39 is slidably fitted onto the first guide rail 40, which is fixed to the lifting beam 34. Two first lead screw nut sliders 39 are connected to each end of the sliding beam 35. A second lead screw 41 is rotatably mounted on the top of the sliding beam 35. A second lead screw nut slider 42 is threaded onto the second lead screw 41. The second lead screw nut slider 42 is slidably fitted onto the second guide rail 43, which is fixed to the sliding beam 35. A sliding seat 36 is mounted on the second lead screw nut slider 42. A first motor 44 and a second motor 45 are respectively installed on the lifting beam 34 and the sliding crossbeam 35. The output shaft of the first motor 44 is connected to the first lead screw 38, and the output shaft of the second motor 45 is connected to the second lead screw 41. The lifting cylinder 37 drives the lifting beam 34 to move up and down, so that the horizontal feeding mechanism can drive the circuit board to move up and down, that is, the horizontal feeding mechanism can drive the circuit board to move along the Y-axis. The first motor 44 drives the first lead screw 38 to rotate, so that the first lead screw nut slider 39 drives the sliding crossbeam 35 to move along the axial direction of the first lead screw 38. That is, the horizontal feeding mechanism can drive the circuit board to move along the Y-axis. The circuit board moves along the X-axis, and the second motor 45 drives the second lead screw 41 to rotate, causing the second lead screw nut slider 42 to drive the sliding seat 36 to move along the axial direction of the second lead screw 41. The horizontal feeding mechanism is installed on the sliding seat 36, which means that the horizontal feeding mechanism can drive the circuit board to move along the Y-axis, realizing the flexible movement and precise positioning of the circuit board in the X, Y, and Z directions. With the rapid switching of the horizontal feeding mechanism, small holes at different positions on the circuit board can be continuously inspected without frequent equipment adjustments or tooling changes, greatly shortening the inspection cycle and meeting the high-efficiency inspection needs of mass production.

[0038] Example 3

[0039] Based on Embodiment 2, a threaded post 46 is coaxially fixed to the large-diameter end of the high-precision detection cone rod 2. A threaded hole 47 is provided on the top of the detection worktable 1. The threaded post 46 is threaded into the threaded hole 47. By setting the threaded post 46, the high-precision detection cone rod 2 can be detachably installed on the detection worktable 1, which facilitates the replacement of the high-precision detection cone rod 2 of different sizes and the adjustment of the detection range of the hole diameter, so as to meet the detection of different types of hole diameters on the circuit board.

[0040] Example 4

[0041] Because the threads are removable, they are prone to loosening. Since the hole diameters on circuit boards are very small, even slight loosening can cause significant testing errors, resulting in a large discrepancy between the test results and the actual values. This can render certain hole diameters on subsequent circuit boards unusable. Therefore, based on Example 3, as... Figure 1 and Figure 8As shown, the testing workbench 1 is equipped with an anti-loosening mechanism, which includes a limiting rotating post 48 and a limiting pin 49. The limiting rotating post 48 is rotatably connected to the testing workbench 1 via a bearing. The testing workbench 1 has a cavity 50. The bottom wall of the threaded hole 47 has a through hole 51 coaxially opened, which connects to the cavity 50. The bottom of the threaded post 46 is coaxially fixed with a limiting post 52, which is rectangular in shape. The top of the limiting rotating post 48 passes into the cavity 50 and has a rectangular limiting groove 53. The axial length of the rectangular limiting groove 53 is greater than the axial length of the limiting post 52. The limiting post 52 passes through the through hole 51 and fits into the rectangular limiting groove 53. The bottom of the limiting rotating post 48 is located at the bottom of the testing workbench 1. The bottom of the worktable 1 protrudes through a limiting cone hole 54 on the side wall of the limiting rotating column 48, which is located below the inspection worktable 1. The limiting pin 49 has the freedom to move closer to or further away from the limiting rotating column 48. The limiting pin 49 is inserted into the limiting cone hole 54 to restrict the rotation of the limiting rotating column 48. When installing the high-precision inspection cone rod 2, the limiting pin 49 is separated from the limiting cone hole 54, allowing the limiting rotating column 48 to rotate normally. During the process of screwing the threaded column 46 into the threaded hole 47, the limiting column 52 passes through the through hole 51 into the cavity 50. When the limiting column 52 and the rectangular limiting groove 53 are intersected, the limiting column 52 abuts against the top of the limiting rotating column 48. The threaded post 46 cannot be fully screwed into the threaded hole 47. The position of the rectangular limiting groove 53 is adjusted by rotating the limiting post 48, allowing the limiting post 52 to smoothly insert into the rectangular limiting groove 53. To facilitate the rotation of the limiting post 48, a rotating arm is fixed to the bottom of the limiting post 48. The rotating arm extends from one side of the inspection workbench 1. The worker can deflect the limiting post 48 by deflecting the rotating arm, allowing the limiting post 52 to smoothly insert into the rectangular limiting groove 53. Through the cooperation of the limiting post 52 and the rectangular limiting groove 53, the limiting post 52 and the limiting post 48 are connected together. At this time, rotating the high-precision inspection cone 2 allows the threaded post 46 to continue to be screwed into the threaded hole 47. The threaded post 46 also has... With high machining accuracy, when the threaded post 46 is fully screwed into the threaded hole 47, the bottom surface of the high-precision detection cone 2 is flush with the detection origin of the high-precision distance sensor 3, avoiding the impact of installation error on the detection accuracy. After the threaded post 46 is screwed into place, the limiting cone hole 54 of the limiting rotating post 48 is located on the moving path of the limiting pin 49. Inserting the limiting pin 49 into the limiting cone hole 54 restricts the rotational freedom of the limiting rotating post 48, thus preventing the threaded fit of the threaded post 46 from loosening and rotating. While ensuring that the high-precision detection cone 2 is detachable, it can also ensure that the high-precision detection cone 2 can maintain high-precision installation for a long time without affecting its detection accuracy.

[0042] Example 5

[0043] Due to machining or installation errors, after the threaded post 46 is installed, the positions of the limiting cone hole 54 and the limiting pin 49 may shift, causing the limiting pin 49 to fail to insert into the limiting cone hole 54. Therefore, based on embodiment four, as follows... Figures 1 to 8 As shown, the anti-loosening mechanism also includes a large gear ring 55 and a self-locking motor 56. The large gear ring 55 is rotatably mounted on the bottom of the inspection workbench 1, and the self-locking motor 56 is mounted on the inspection workbench 1. The output shaft of the self-locking motor 56 is connected to a pinion 57, which meshes with the large gear ring 55. A limit cylinder 58 is horizontally mounted on the large gear ring 55, and the output shaft of the limit cylinder 58 is connected to a limit pin 49. When the threaded column 46 rotates to its position, the limit cylinder 58 drives the limit pin 49 to move closer to the limit cone hole 54. When there is a deviation between the limit pin 49 and the limit cone hole 54, the limit pin 49 abuts against the side wall of the limit rotating column 48. At this time, the movement path of the limit cylinder 58 has not reached the specified value, which indicates that there is a deviation between the position of the limit pin 49 and the limit cone hole 54. At this time, the self-locking motor 56 drives the pinion 57 to rotate, and the pinion 57 drives the large gear ring 55 to rotate. By reducing the transmission... The high rotational accuracy of the large gear ring 55 is achieved through a dynamic ratio mechanism. A certain pressure is applied by the limit cylinder 58, and the position between the limit pin 49 and the limit cone hole 54 is adjusted via the large gear ring 55. When the limit pin 49 corresponds to the limit cone hole 54, it can smoothly insert into the limit cone hole 54 under the pressure of the limit cylinder 58. The extension / retraction value of the limit cylinder 58 determines whether the limit pin 49 is fully inserted into the limit cone hole 54. Once fully inserted, both the self-locking motor 56 and the limit cylinder 58 stop operating, thus overcoming errors and locking the limit rotating post 48, preventing loosening of the threaded post 46. In practice, the rotation direction of the large gear ring 55 is the same as the threading direction of the threaded post 46, ensuring that when the limit pin 49 abuts against the limit rotating post 48, it does not cause the limit rotating post 48 to rotate, thus keeping the threaded post 46 always in a tightened state.

[0044] Example 6

[0045] Based on Example 5, such as Figures 1 to 4As shown, the side slide bar 8 includes a large-diameter rod 11 and a small-diameter rod 12. The large-diameter rod 11 slides through the base plate 4. A detection hole 13 is opened at the bottom of the large-diameter rod 11 along its own axial direction. One end of the small-diameter rod 12 is slidably fitted in the detection hole 13, and the other end is connected to the rectangular feeding plate frame 5. A spring 14 is sleeved on the small-diameter rod 12. The two ends of the spring 14 are respectively connected to the rectangular feeding plate frame 5 and the large-diameter rod 11. A position detection component is set in the detection hole 13. The position detection component includes a drive plate 15, a detection spring 16, a pressure plate 17, and a pressure sensor 18. The two ends of the detection spring 16 are respectively connected to the drive plate 15 and the pressure plate 17. The drive plate 15 is connected to the small-diameter rod 12. The pressure sensor 18 is installed on the inner top wall of the detection hole 13. The pressure plate 17 contacts the pressure shaft of the pressure sensor 18. The structure of the middle slide bar 10 is the same as that of the side slide bar 8. Similarly, the middle slide bar 10 is also equipped with a position detection component. The circuit board is equipped with a position detection component. The horizontal feeding mechanism drives the circuit board downward, allowing the high-precision detection cone 2 to pass through the small hole of the circuit board. When the circuit board can no longer move downward, the three-degree-of-freedom conveying mechanism continues to drive the circuit board downward. At this time, the small-diameter rod 12 moves the compression spring 14 into the detection hole 13. Then, the small-diameter rod 12 drives the pressure plate 17 to squeeze the pressure shaft of the pressure sensor 18 through the drive plate 15. The pressure signal of the pressure sensor 18 determines whether the circuit board has moved into position on the high-precision detection cone 2. When the pressure reaches the set value, the diameter of the small hole of the circuit board corresponds to the diameter of the high-precision detection cone 2. Then, the three-degree-of-freedom conveying mechanism stops driving, and the high-precision distance sensor 3 starts to perform distance detection. On the one hand, the spring 14 can buffer the circuit board to avoid continuous deformation under pressure, and on the other hand, it can accurately determine whether the circuit board has moved into position downward.

[0046] Example 7

[0047] Based on Embodiment Six, the top end of the side slide bar 8 passes through the substrate 4 and is connected to a first rack 19, and the top end of the middle slide bar 10 passes through the substrate 4 and is connected to a second rack 20. The second rack 20 is arranged opposite to the first rack 19. A switching reduction motor 21 is mounted on the substrate 4, and the output shaft of the switching reduction motor 21 is connected to a switching gear 22. The switching gear 22 is located between the first rack 19 and the second rack 20. Both the first rack 19 and the second rack 20 mesh with the switching gear 22. The switching reduction motor 21 drives the switching gear 22 to rotate, and the switching gear 22 simultaneously drives the first rack 19 and the second rack 20 to move. Since the first rack 19 and the second rack 20 are arranged opposite to each other, the moving direction of the first rack 19 is opposite to the moving direction of the second rack 20. As a result, when the feeding tray 6 moves upward, the rectangular feeding plate frame 5 moves downward, so that the feeding tray 6 and the rectangular feeding plate frame 5 can only be in working state independently, which facilitates switching the operation of the feeding tray 6 or the rectangular feeding plate frame 5 according to the position of the small hole on the circuit board.

[0048] Example 8

[0049] Due to the operational error of the three-degree-of-freedom conveying mechanism, even if the path is planned according to the coordinates of the aperture, it cannot be guaranteed that the small aperture is coaxial with the high-precision detection cone 2, resulting in a certain positional deviation. Therefore, based on Example 7, as follows... Figures 1 to 6As shown, the horizontal feeding mechanism also includes a top plate 23, a transverse micro-motion plate 24, and a longitudinal micro-motion plate 25. The top plate 23 is mounted on the three-degree-of-freedom conveying mechanism. The transverse micro-motion plate 24 is slidably mounted on the bottom of the top plate 23, and the longitudinal micro-motion plate 25 is slidably mounted on the bottom of the transverse micro-motion plate 24. A connecting rod 26 is fixedly mounted on the top of the base plate 4, and the connecting rod 26 is fixedly connected to the longitudinal micro-motion plate 25. The moving direction of the transverse micro-motion plate 24 is perpendicular to the moving direction of the longitudinal micro-motion plate 25 on the horizontal plane. Two transverse inverted T-shaped grooves 27 are parallel to each other on the bottom of the top plate 23. A transverse inverted T-shaped block 28 is slidably fitted in the transverse inverted T-shaped grooves 27, and the transverse inverted T-shaped block 28 is fixedly connected to the transverse micro-motion plate 24. The transverse inverted T-shaped grooves 27 are provided with A transverse telescopic rod 29 is provided, with its two ends connected to a top plate 23 and a transverse inverted T-shaped block 28, respectively. A transverse micro-motion spring 30 is fitted on the transverse telescopic rod 29. Two longitudinal inverted T-shaped grooves 59 are parallel to each other at the bottom of the transverse micro-motion plate 24. The longitudinal inverted T-shaped grooves 59 are perpendicular to the transverse inverted T-shaped grooves 27. A longitudinal inverted T-shaped block 31 is slidably fitted inside the longitudinal inverted T-shaped grooves 59. The longitudinal inverted T-shaped block 31 is fixedly connected to the longitudinal micro-motion plate 25. A longitudinal telescopic rod 32 is provided inside the longitudinal inverted T-shaped grooves 59, with its two ends connected to the transverse micro-motion plate 24 and the longitudinal inverted T-shaped block 31, respectively. A longitudinal micro-motion spring 33 is fitted on the longitudinal telescopic rod 32. The elastic modulus of the longitudinal micro-motion spring 33 is small. Regarding the elastic modulus of spring 14, when the high-precision detection cone 2 is inserted into the small hole of the circuit board, and the small hole and the high-precision detection cone 2 are not coaxial, the side wall of the high-precision detection cone 2 will squeeze the inner wall of the small hole. Under the guidance of the cone surface of the high-precision detection cone 2, and because the elastic modulus of the longitudinal micro-motion spring 33 is less than that of spring 14, the transverse micro-motion plate 24 and the longitudinal micro-motion plate 25 are first finely adjusted for positioning. Specifically, when the small diameter and the high-precision detection cone 2 only have a lateral offset, under the squeezing force of the circuit board and the high-precision detection cone 2, the transverse inverted T-shaped block 28 squeezes the transverse micro-motion spring 30 to move, thereby achieving fine adjustment of the lateral position on the horizontal plane. When the circuit shifts, the pressure exerted by the circuit board and the high-precision detection cone 2 causes the longitudinal inverted T-shaped block 31 to compress the longitudinal micro-motion spring 33, thus achieving fine adjustment of the longitudinal position on the horizontal plane. When both lateral and longitudinal shifts occur simultaneously, the lateral micro-motion plate 24 and the longitudinal micro-motion plate 25 move adaptively at the same time, so that the small hole of the circuit board can completely match the corresponding position of the high-precision detection cone 2. After the matching is completed, the circuit board can no longer move downward. At this time, the pressure exerted by the circuit board and the high-precision detection cone 2 increases, which drives the small diameter rod 12 to compress the spring 14, causing the small diameter rod 12 to act on the position detection component to send a matching completion signal. It has the ability of micro-motion adaptive adjustment, thereby further improving the detection accuracy.

[0050] A method for detecting the aperture of a circuit board, utilizing the aforementioned circuit board aperture detection system, includes the following steps:

[0051] S1. Select the feeding and adsorption area according to the position of the hole to be detected on the circuit board. If the hole is located in the middle of the circuit board, it is fed through the rectangular feeding plate frame 5; if the hole is located around the circuit board, it is fed through the feeding tray 6, so that the hole to be detected is in a completely exposed state.

[0052] S2. After the circuit board is horizontally adsorbed and loaded, the circuit board is driven by the three-degree-of-freedom conveying mechanism to drive the corresponding high-precision detection cone rod.

[0053] S3. The circuit board moves downward, allowing the high-precision detection cone 2 to pass into the small hole to be detected. When the diameter of the high-precision detection cone 2 matches the diameter of the small hole to be detected, the circuit board can no longer move downward.

[0054] S4. The height of the circuit board is detected by the high-precision distance sensor 3, which reflects the position of the detection hole on the high-precision detection cone 2. The diameter of the high-precision detection cone 2 changes linearly with its own axial height. The inner diameter of the detection hole can be obtained by using the high-precision detection cone 2 with known dimensions, thus completing the inner diameter detection of the circuit board hole.

Claims

1. A circuit board aperture detection system, characterized in that, The system includes a three-degree-of-freedom conveying mechanism and a detection worktable. The detection worktable is arranged within the working range of the three-degree-of-freedom conveying mechanism. A small-diameter detection component is installed on the detection worktable, comprising a high-precision detection cone and a high-precision distance sensor. The high-precision detection cone is vertically mounted on the top surface of the detection worktable and is truncated into a frustum shape, with its small-diameter end positioned away from the detection worktable. The high-precision distance sensor is mounted on the top surface of the detection worktable, with its detection path vertically upwards. A horizontal feeding mechanism is installed on the three-degree-of-freedom conveying mechanism, which is used to drive the horizontal feeding mechanism. The feeding mechanism moves along the X, Y, and Z axes in a spatial coordinate system. The horizontal feeding mechanism includes a substrate, a rectangular feeding plate frame, and a feeding tray. The feeding tray is arranged in the inner circle of the rectangular feeding plate frame. The bottom of the rectangular feeding plate frame has several first negative pressure holes. The top of the rectangular feeding plate frame is connected to a side sliding rod. The bottom of the feeding tray has several second negative pressure holes. The top of the feeding tray is connected to a central sliding rod. Both the central sliding rod and the side sliding rod are slidably mounted on the substrate. Both the central sliding rod and the side sliding rod have a degree of freedom to move in the vertical direction. The feeding tray and the rectangular feeding plate frame are arranged alternately in the vertical direction, so that the circuit board is fed only through the feeding tray or the rectangular feeding plate frame at a time. The high-precision detection cone rod has a threaded post coaxially fixed to its large-diameter end. The top of the detection worktable has a threaded hole, and the threaded post is threaded into the threaded hole. The detection worktable is equipped with an anti-loosening mechanism, which includes a limiting rotating post and a limiting pin. The limiting rotating post is rotatably connected to the detection worktable via a bearing. The detection worktable has a cavity. The bottom wall of the threaded hole has a through hole coaxially connected to the cavity. The bottom of the threaded post is coaxially fixed with a limiting post, which is cuboid in shape. The top of the limiting rotating post passes into the cavity and has a rectangular limiting groove. The axial length of the rectangular limiting groove is greater than the axial length of the limiting post. The limiting post passes through the through hole and is fitted into the rectangular limiting groove. The bottom of the limiting rotating post extends out from the bottom of the detection worktable. The side wall of the limiting rotating post has a limiting cone hole located below the detection worktable. The limiting pin has the freedom to move closer to or away from the limiting rotating post. The limiting pin is inserted into the limiting cone hole to restrict the rotation of the limiting rotating post. The anti-loosening mechanism also includes a large gear ring and a self-locking motor. The large gear ring is rotatably mounted on the bottom of the inspection workbench, and the self-locking motor is mounted on the inspection workbench. The output shaft of the self-locking motor is connected to a pinion, which meshes with the large gear ring. A limit cylinder is horizontally mounted on the large gear ring, and the output shaft of the limit cylinder is connected to a limit pin.

2. The circuit board aperture detection system according to claim 1, characterized in that, The side slide rod includes a large-diameter rod and a small-diameter rod. The large-diameter rod slides through the base plate. A detection hole is opened at the bottom of the large-diameter rod along its own axial direction. One end of the small-diameter rod slides in the detection hole, and the other end is connected to a rectangular feeding plate frame. A spring is sleeved on the small-diameter rod, and the two ends of the spring are respectively connected to the rectangular feeding plate frame and the large-diameter rod.

3. The circuit board aperture detection system according to claim 2, characterized in that, A position detection component is provided inside the detection hole. The position detection component includes a drive plate, a detection spring, a pressure plate, and a pressure sensor. The two ends of the detection spring are respectively connected to the drive plate and the pressure plate. The drive plate is connected to a small-diameter rod. The pressure sensor is installed on the inner top wall of the detection hole. The pressure plate contacts the pressure shaft of the pressure sensor. The structure of the middle slide rod is the same as that of the side slide rod.

4. The circuit board aperture detection system according to claim 1, characterized in that, The top end of the side slide rod passes through the base plate and is connected to a first rack. The top end of the middle slide rod passes through the base plate and is connected to a second rack. The second rack is arranged opposite to the first rack. A switching reduction motor is mounted on the base plate. The output shaft of the switching reduction motor is connected to a switching gear. The switching gear is located between the first rack and the second rack. Both the first rack and the second rack mesh with the switching gear.

5. The circuit board aperture detection system according to claim 1, characterized in that, The horizontal feeding mechanism also includes a top plate, a transverse micro-motion plate, and a longitudinal micro-motion plate. The top plate is mounted on a three-degree-of-freedom conveying mechanism. The transverse micro-motion plate is slidably mounted on the bottom of the top plate. The longitudinal micro-motion plate is slidably mounted on the bottom of the transverse micro-motion plate. A connecting rod is fixed to the top of the base plate. The connecting rod is fixedly connected to the longitudinal micro-motion plate. The direction of movement of the transverse micro-motion plate is perpendicular to the direction of movement of the longitudinal micro-motion plate on the horizontal plane.

6. The circuit board aperture detection system according to claim 5, characterized in that, The bottom of the top plate has two parallel horizontal inverted T-shaped grooves. A horizontal inverted T-shaped block is slidably fitted in each horizontal inverted T-shaped groove. The horizontal inverted T-shaped block is fixedly connected to a horizontal micro-motion plate. A horizontal telescopic rod is installed in each horizontal inverted T-shaped groove. The two ends of the horizontal telescopic rod are respectively connected to the top plate and the horizontal inverted T-shaped block. A horizontal micro-motion spring is sleeved on the horizontal telescopic rod. The bottom of the horizontal micro-motion plate has two parallel vertical inverted T-shaped grooves. The vertical inverted T-shaped grooves are perpendicular to the horizontal inverted T-shaped grooves. A vertical inverted T-shaped block is slidably fitted in each vertical inverted T-shaped groove. The vertical inverted T-shaped block is fixedly connected to a vertical micro-motion plate. A vertical telescopic rod is installed in each vertical inverted T-shaped groove. The two ends of the vertical telescopic rod are respectively connected to the horizontal micro-motion plate and the vertical inverted T-shaped block. A vertical micro-motion spring is sleeved on the vertical telescopic rod.

7. The circuit board aperture detection system according to claim 1, characterized in that, The three-degree-of-freedom conveying mechanism includes a lifting beam, a sliding crossbeam, and a sliding seat. Two lifting beams are arranged in parallel, and each lifting beam has a degree of freedom to move in the vertical direction. The two ends of the sliding crossbeam are slidably mounted on the two lifting beams respectively. The sliding seat is slidably mounted on the sliding crossbeam, and the direction of movement of the sliding crossbeam is perpendicular to the direction of movement of the sliding seat in the horizontal plane.

8. The circuit board aperture detection system according to claim 7, characterized in that, Both ends of the lifting beam are vertically equipped with lifting cylinders. The telescopic shafts of the lifting cylinders are connected to the lifting beam. A first lead screw is rotatably mounted on the top of the lifting beam. A first lead screw nut slider is threaded onto the first lead screw. The first lead screw nut slider slides onto a first guide rail, which is fixed to the lifting beam. Two first lead screw nut sliders are respectively connected to both ends of the sliding crossbeam. A second lead screw is rotatably mounted on the top of the sliding crossbeam. A second lead screw nut slider is threaded onto the second lead screw. The second lead screw nut slider slides onto a second guide rail, which is fixed to the sliding crossbeam. A sliding seat is mounted on the second lead screw nut slider. A first motor and a second motor are respectively mounted on the lifting beam and the sliding crossbeam. The output shaft of the first motor is driven by the first lead screw, and the output shaft of the second motor is driven by the second lead screw.

9. A method for detecting the aperture of a circuit board, utilizing the circuit board aperture detection system as described in claim 1, characterized in that, Includes the following steps: S1. Select the feeding and adsorption area according to the position of the hole to be detected on the circuit board. If the hole is located in the middle of the circuit board, feed it through the rectangular feeding plate frame; if the hole is located around the circuit board, feed it through the feeding tray, so that the hole to be detected is completely exposed. S2. After the circuit board is horizontally adsorbed and loaded, the circuit board is driven by the three-degree-of-freedom conveying mechanism to drive the corresponding high-precision detection cone rod. S3. The circuit board moves downward, allowing the high-precision detection cone to pass through the small hole to be detected. When the diameter of the high-precision detection cone matches the diameter of the small hole to be detected, the circuit board can no longer move downward. S4. The height of the circuit board is detected by a high-precision distance sensor, which reflects the position of the detection hole on the high-precision detection cone. The diameter of the high-precision detection cone changes linearly with its own axial height. The inner diameter of the detection hole can be obtained by using the high-precision detection cone with known dimensions, thus completing the inner diameter detection of the circuit board hole.

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