Electronic component defect self-adaptive detection device and method based on machine vision

Abstract

The invention belongs to the technical field of electronic component defect detection, and particularly relates to an electronic component defect self-adaptive detection device and method based on machine vision. The negative pressure pipe is used for conveying a to-be-tested piece under a negative pressure condition, an emptying mechanism used for bending and emptying the negative pressure pipe is arranged in the cabinet body, and when the to-be-tested piece enters the cabinet body, a port of the negative pressure pipe sucks the to-be-tested piece, so that the to-be-tested piece advances along the interior of the negative pressure pipe in a suspended manner; moreover, the aerial mechanism carries out the vibration reduction of the negative pressure pipe, so as to reduce the friction between the to-be-tested piece and the negative pressure pipe. The machine vision camera penetrates through the negative pressure tube; the method comprises the following steps: putting pieces to be tested into a vibration disc, conveying the pieces to be tested one by one by utilizing the vibration effect of the vibration disc until the pieces enter a cabinet body, and conveying the pieces to be tested into a negative pressure pipe. According to the device, the to-be-detected piece is conveyed in the flat-opening pipe under the negative pressure condition, meanwhile, vibration in the conveying process is reduced, scratches for shielding the to-be-detected piece in the device are effectively reduced, and interference on a visual detection result is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of electronic component defect detection technology, specifically relating to an adaptive detection device and method for electronic component defects based on machine vision. Background Technology

[0002] Electronic components may have defects during the manufacturing process, such as whether the markings on the front are clear and complete, whether the laser markings or logos on the back are clear and complete, or whether there are defects such as cracks, scratches, deformations, or poor solder joints on the front and back. These defects are usually placed downstream of the production line and visually inspected by industrial cameras, combined with machine learning and deep learning algorithms to identify defect features, such as YOLO, SSD, and Faster R-CNN.

[0003] On the product inspection line, products such as capacitors, resistors, transformers, and diodes are separated from the conveyor belt by a high-frequency vibrating plate or a high-speed rotating plate and quickly and in bulk are transported to the conveyor belt. This process needs to be precisely matched with the speed of the vision system to avoid waiting or blocking the production line. High-resolution machine vision cameras are responsible for capturing clear images of components on a conveyor belt. They generally have high dynamic range, long exposure time (suitable for highly reflective surfaces) or other special imaging capabilities, and can adapt to observation needs at different angles and speeds. They are often suspended above or to the side of the product by an alloy bracket. The rotary loading stage, driven by a servo motor, rotates at a constant speed, receiving electronic components fed by a conveyor belt and delivering them one by one into the field of view of a high-resolution machine vision camera. This rotary loading stage is typically made of transparent glass to ensure good light transmission for supplemental lighting of the high-resolution machine vision camera. However, in the actual inspection of electronic components, the following aspects still need improvement: 1. Electronic components are placed on a transparent glass stage. After the image is captured, the components are fed out using compressed air. Friction occurs between the components and the transparent glass stage. In addition, the detection speed of electronic components can reach thousands per minute, causing scratches to appear on the transparent glass stage due to wear. These scratches obscure the electronic components and become a factor that interferes with the visual inspection results.

[0004] 2. When electronic components are unloaded, several air pipes arranged above the transparent glass loading platform intermittently emit compressed air to blow the components. The compressed air impacts the transparent glass loading platform. In addition, the impact can reach thousands of times per minute, which may cause the transparent glass loading platform to vibrate. On the one hand, this increases the friction between the transparent glass loading platform and the electronic components. On the other hand, the vibration of the electronic components may damage their solder joints. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive detection device and method for electronic component defects based on machine vision. The device transports the test component under negative pressure inside a flat-mouthed tube, while reducing vibration during transport. This effectively reduces scratches on the test component inside the device and greatly reduces interference with the visual inspection results.

[0006] The specific technical solution adopted by this invention is as follows: An adaptive defect detection device for electronic components based on machine vision, comprising: Cabinet; The negative pressure tube that transports the test piece under negative pressure conditions is equipped with an air-lifting mechanism inside the cabinet for bending and air-lifting the negative pressure tube. When the test piece enters the cabinet, the port of the negative pressure tube attracts the test piece, causing the test piece to travel suspended along the inside of the negative pressure tube. Furthermore, the levitation mechanism dampens the negative pressure tube to reduce friction between the test piece and the negative pressure tube; A machine vision camera extends through the negative pressure tube, and the machine vision camera is used to acquire images of the test piece inside the negative pressure tube.

[0007] As an optional solution, the machine vision camera is provided with an outer sheath that wraps around the negative pressure tube, an inner lining that penetrates the negative pressure tube and the outer sheath, and an outer lining that wraps around the outer sheath. An LED lamp holder and a glass liner that penetrate the negative pressure tube are installed on the inner wall of the outer sheath tube; The glass liner is used to separate the machine vision camera, the LED lamp head, and the device under test.

[0008] As an optional solution, the levitation mechanism includes: A double-layered armor plate is installed along the arc surface on the surface of the negative pressure pipe, and the double-layered armor plate is used to maintain the shape of the negative pressure pipe; A suspended bracket is provided outside the negative pressure pipe, and a tensioning member is connected between the inner wall of the suspended bracket and the outer side of the compound armor plate. A damper located at the bottom of the suspended bracket is used to reduce the vibration of the suspended bracket.

[0009] As an alternative, the end of the negative pressure pipe is connected to a discharge chute, two distribution pipes penetrating the outside of the discharge chute, and two compressed air nozzles; The two distribution pipes are staggered, and the two compressed air nozzles are respectively positioned directly opposite the two distribution pipes.

[0010] As an optional solution, the cabinet also includes a bearing frame and two limiting rollers spaced apart inside the bearing frame; A transmission gear is installed between one end of the two limiting rollers, and a servo motor for driving the two limiting rollers is installed on the outside of the bearing frame. When the servo motor is working, the two limiting rollers feed the test piece into the port of the negative pressure tube and separate subsequent test pieces from the negative pressure tube, so as to realize the feeding of test pieces one by one.

[0011] As an optional solution, a third support flange and a perforated plate are connected vertically between the bottom surface of the suspended bracket and the top of the damper. The perforated plate connects the third support flange and the damper; A guide rod is fixed inside the cabinet, passing through the hole in the perforated plate, and the guide rod avoids the negative pressure pipe.

[0012] As an alternative, an alloy gas pipe runs through the bottom of the negative pressure pipe, and the alloy gas pipe is connected in sequence to a vacuum buffer tank and a variable frequency fan; When the variable frequency fan starts, the alloy air pipe draws air from inside the negative pressure pipe to create a negative pressure condition.

[0013] As an optional solution, the cabinet also includes an internal controller and an acceleration sensor electrically connected to the internal controller; The accelerometer is vertically mounted on the outside of the outer sheath and is used to monitor the vibration signal of the negative pressure tube. The internal controller receives vibration signals and controls the wind speed of the variable frequency fan based on the vibration signals.

[0014] As an optional solution, both of the two material distribution pipes are equipped with a transfer platform on the outside and a sponge pad inside the transfer platform; The inner wall of the transfer table is provided with an inverted T-shaped groove and a support plate located inside the inverted T-shaped groove, and the support plate is connected to the sponge pad.

[0015] A method for detecting defects in electronic components includes the following steps: The test piece is placed in the vibratory feeder, and the vibration of the vibratory feeder is used to transport the test piece one by one until it enters the cabinet and is sent into the negative pressure tube. A negative pressure airflow is formed inside the negative pressure tube, causing the test piece to travel suspended along the inside of the negative pressure tube, reducing the friction between the test piece and the negative pressure tube, thereby reducing scratches caused by the inside of the device obstructing the test piece. At least four machine vision cameras penetrating the negative pressure tube acquire images of the workpiece from different angles inside the tube. The image signals are transmitted to an external controller, which uses a preset algorithm to identify defects in the workpiece images. The negative pressure tube is opened to maintain its shape and to support the tube as it bends and suspends in the air. This prevents increased friction between the negative pressure tube and the test piece and avoids damage to the weld joints caused by vibration of the test piece. Divide the testing area and the unloading area, and place the negative pressure pipe in the testing area to avoid friction between the test piece and the testing area when the test piece is unloaded in the unloading area; Control two compressed air streams to separately blow defective and qualified products; Stop the compressed airflow and feeding, spray a measured amount of atomized cleaning agent into the negative pressure pipe, and use the negative pressure airflow to clean the inner wall of the negative pressure pipe.

[0016] The technical effects achieved by this invention are as follows: To reduce friction on the test piece during the testing process, this invention employs a flat-mouthed negative pressure tube to transport the test piece under negative pressure conditions. This allows the test piece to travel suspended inside the negative pressure tube, and subsequent test pieces are separated from the negative pressure tube for sequential feeding. This effectively reduces scratches that obstruct the test piece inside the device, significantly reducing interference with visual inspection results. Simultaneously, it reduces vibration between the test piece and the negative pressure tube, preventing increased friction between them and avoiding damage to the solder joints caused by vibration.

[0017] This invention combines a negative pressure tube and its associated armor while transporting the test piece. The associated armor can open the negative pressure tube along an elliptical path to maintain its shape, allowing it to bend and levitate after being supported. Furthermore, the associated armor dampens the negative pressure tube, reducing friction between the test piece and the negative pressure tube.

[0018] This invention divides the testing area and the unloading area, effectively avoiding scratches caused by friction in the testing area when the test parts are unloaded. It controls two compressed air streams to blow defective products and qualified products separately. When the upper compressed air nozzle sprays air, it can blow defective products into the adjacent distribution pipe. When the lower compressed air nozzle sprays air, it can blow qualified products into the adjacent distribution pipe. Moreover, it will not rub against the negative pressure pipe.

[0019] After the visual inspection of the test piece is completed, the present invention uses an atomized cleaning agent and negative pressure airflow to clean the inner wall of the negative pressure tube. The residue is minimal, the cleaning is convenient, no additional cleaning equipment is required, and the insertion or puncture of the negative pressure tube is avoided, making it more user-friendly to the entire device. Attached Figure Description

[0020] Figure 1 This is a front view of the adaptive detection device for electronic component defects in Embodiment 1 of the present invention; Figure 2 This is a rear view of the adaptive detection device for electronic component defects in Embodiment 1 of the present invention; Figure 3 This is a front view of the negative pressure pipe in Embodiment 1 of the present invention; Figure 4 This is a top view of the negative pressure tube in Embodiment 1 of the present invention; Figure 5 This is a bottom view of the negative pressure pipe in Embodiment 1 of the present invention; Figure 6 This is a front view of the limiting roller in Embodiment 1 of the present invention; Figure 7 This is a partial cross-sectional view of the negative pressure pipe in Embodiment 1 of the present invention; Figure 8 This is a structural schematic diagram of the assembled state of the compound armor plate and the suspended bracket in Embodiment 1 of the present invention; Figure 9 This is a side view of the negative pressure mechanism in Embodiment 1 of the present invention; Figure 10 This is a front view of the accelerometer sensor in Embodiment 1 of the present invention; Figure 11 This is a cross-sectional view of the transfer station in Embodiment 1 of the present invention; Figure 12 This is a system block diagram of the external controller control signal transmission in Embodiment 1 of the present invention; Figure 13 This is a system block diagram of the internal controller control signal transmission in Embodiment 1 of the present invention; Figure 14 This is a top view of the test piece in the cracked state according to the present invention; Figure 15 This is a flowchart of the electronic component defect detection method in Embodiment 2 of the present invention.

[0021] The attached diagram lists the components represented by each number as follows: 1. Cabinet; 2. Vibratory feeder; 3. Material guide chute; 4. Feeding conveyor belt; 5. Bearing bracket; 501. First support flange; 6. Limiting roller; 601. Transmission gear; 7. Servo motor; 8. Negative pressure pipe; 9. Machine vision camera; 10. Outer sheath; 11. Inner edging; 12. LED lamp head; 13. Outer edging; 14. Glass liner; 15. Double armor plate; 16. Pulling component; 17. Suspended bracket; 18. Damper; 19. Second support flange; 20. Third support flange; 21. Perforated plate; 22. Guide rod; 23. Alloy air pipe; 24. Vacuum buffer tank; 25. Variable frequency fan; 26. Accelerometer sensor; 27. Internal controller; 28. Discharge chute; 29. ​​Distribution pipe; 30. Compressed air nozzle; 31. Transfer table; 32. Inverted T-slot; 33. Bearing plate; 34. Sponge pad. Detailed Implementation

[0022] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention.

[0023] Electronic components may experience issues during manufacturing, such as insufficient soldering temperature, inadequate soldering time, oxidation of pads or leads, resulting in poor soldering; fractures due to poor machining processes like drilling; or cracks caused by mechanical stress. (See also...) Figure 14 As can be seen, obvious cracks have appeared on the surface of the electronic component, directly affecting product quality. Therefore, downstream of the electronic component production line, machine vision is generally used for appearance inspection. Existing defect detection algorithms include: The YOLO module uses rectangular boxes to label defect types. Feature extraction modules, such as SIFT (Scale Invariant Features), HOG (Histogram of Oriented Gradients), and LBP (Local Binary Pattern); SVM models are trained by feeding in preprocessed data and are used for real-time detection of electronic components on the production line, such as YOLOv5 for detecting cold solder joints and bridging.

[0024] When inspecting electronic components, they are placed on a transparent glass stage. After the image is captured, the components are fed out using compressed air. Friction occurs between the components and the transparent glass stage. In addition, the inspection speed of electronic components can reach thousands per minute, causing scratches to appear on the transparent glass stage due to wear. These scratches can obscure the electronic components and become a factor that interferes with the visual inspection results.

[0025] Therefore, this application improves the machine vision inspection device for inspecting electronic components by using negative pressure airflow to greatly reduce the friction on electronic components during the inspection process, abandoning the traditional transparent glass loading stage and avoiding scratches on the transparent glass caused by friction that would interfere with the subsequent visual inspection of electronic components.

[0026] Example 1: like Figures 1-13 As shown, an adaptive defect detection device for electronic components based on machine vision includes a cabinet 1 and an external controller. To facilitate the loading of electronic components, a vibratory feeder 2 is installed on the outside of the cabinet 1 and grounded. A batch of components to be tested is placed into the vibratory feeder 2, and the components are fed out one by one by vibration. A guide groove 3 and a feeding conveyor belt 4 are installed horizontally on the top of the vibratory feeder 2 by bolts, so that the components to be tested slide one by one through the guide groove 3 and the feeding conveyor belt 4 until they enter the cabinet 1. The machine vision system collects images to complete defect detection and classify defective products into qualified products.

[0027] Among them, see Figure 1 and Figure 12 An external controller is electrically connected to the motor of the vibratory plate 2 and the three-phase asynchronous motor of the feeding conveyor belt 4. It is used to control the discharge of the vibratory plate 2 and the conveying of the feeding conveyor belt 4 to maintain the same speed and rhythm. The working principle of the vibratory plate 2 is mainly to use an electromagnet / motor to generate high-frequency micro-amplitude vibration, and spring plates / shock absorbers to support the hopper and control the vibration direction (tilt or twist). Baffles, notches, air holes, etc., screen the components that meet the orientation.

[0028] See attached document Figure 2 , Figure 3 and Figure 8 In order to feed the test pieces one by one, this embodiment also provides a bearing frame 5 and two limiting rollers 6 installed at intervals inside the bearing frame 5 inside the cabinet 1. Both limiting rollers 6 can rotate relative to the bearing frame 5 through the bearing, and the interval between them is used to hold one test piece. Furthermore, in this embodiment, a servo motor 7 for driving two limit rollers 6 is installed on the outside of the bearing frame 5 by screws as a power source. Since the external controller is electrically connected to the servo motor 7, when the external controller is operated to start the servo motor 7, one of the limit rollers 6 can be driven to rotate. Four sequentially meshing transmission gears 601 are installed between one end of the two limit rollers 6, so that the two limit rollers 6 rotate synchronously in opposite directions. When the servo motor 7 is working, the two limit rollers 6 send the test piece into the port of the negative pressure tube 8 and separate the subsequent test pieces from the negative pressure tube 8, so as to realize the feeding of the test pieces one by one.

[0029] Two transmission gears 601 are coaxially welded to the ends of the two limiting rollers 6, and two other transmission gears 601 are mounted on the outside of the bearing frame 5 via a rotating shaft, enabling them to rotate stably.

[0030] See attached document Figure 2 , Figure 3 and Figure 4 To reduce friction of the test piece during the testing process, the negative pressure tube 8 used in this embodiment transports the test piece under negative pressure conditions. When the test piece enters the cabinet 1, a single test piece passes through two limiting rollers 6 and is attracted by the port of the negative pressure tube 8, causing the test piece to travel suspended along the inside of the negative pressure tube 8. As an optional embodiment, the negative pressure tube 8 is made of UHMWPE (Ultra-High Molecular Weight Polyethylene), which is wear-resistant and scratch-resistant. The cross-section of the negative pressure tube 8 is elliptical, which allows the test piece to be vertically limited after it enters horizontally, preventing the test piece from tipping over. Meanwhile, this embodiment employs at least four machine vision cameras 9 that penetrate the negative pressure tube 8 and are distributed in different positions. These machine vision cameras 9 are used to acquire images of the test piece inside the negative pressure tube 8. The images cover different sides of the test piece. In addition, the test piece is carried by the negative pressure airflow and completes the visual inspection in a suspended manner throughout the process. It hardly rubs against the negative pressure tube 8 and the machine vision cameras 9, effectively reducing scratches inside the device that obstruct the test piece and greatly reducing interference with the visual inspection results.

[0031] The machine vision camera 9 can be an ME2C-G series area scan camera. It transmits image signals to an external controller through the I / O interface. At this time, the ISP algorithm pre-loaded by the external controller can identify defects in the image of the part under test.

[0032] Whether it is the transparent glass loading platform or the negative pressure tube 8, the structures that transport the test piece may vibrate due to airflow. This vibration may increase the friction between the test piece and external objects. In order to reduce this friction, this embodiment needs to add certain vibration reduction measures to the outside of the negative pressure tube 8.

[0033] See attached document Figure 3 , Figure 4 and Figure 7 To facilitate vibration reduction, this embodiment includes an outer sheath 10 that encloses the negative pressure tube 8, an inner lining 11 that penetrates the negative pressure tube 8 and the outer sheath 10, and an outer lining 13 that encloses the outer sheath 10, all bonded to the outside of the machine vision camera 9. The outer sheath 10 is used to support the machine vision camera 9. (See also...) Figure 7 The inner edge 11 and the outer edge 13 respectively seal the front and rear ends of the machine vision camera 9; The outer sheath 10 can be made of transparent silicone material for easy insertion, and both the inner edge 11 and the outer edge 13 can be made of silicone adhesive material for good airtightness. To provide an exposure environment, this embodiment also installs an LED lamp head 12 that penetrates the negative pressure tube 8 and a glass substrate 14 on the inner wall of the outer sheath tube 10. The LED lamp head 12 is electrically connected to an external controller, and the lighting time of the LED lamp head 12 is controlled by a preset program so that the test piece can be illuminated when it reaches the glass substrate 14. The glass liner 14 is used to separate the machine vision camera 9, the LED lamp head 12 and the test piece. In addition, the glass liner 14 has the same curvature as the inner arc surface of the negative pressure tube 8, so as to support the test piece carried by the negative pressure airflow with a smaller contact surface, and the friction between the glass liner 14 and the test piece is small.

[0034] See attached document Figure 4 , Figure 5 and Figure 8 The interior of cabinet 1 also includes: The double armor plate 15 is bonded to the surface of the negative pressure tube 8 along the arc surface. The double armor plate 15 is made of alloy material and can open the negative pressure tube 8 along the elliptical path to maintain the shape of the negative pressure tube 8. The arc-shaped suspended bracket 17 located outside the negative pressure tube 8 has an elastic tension member 16 connecting the inner wall of the suspended bracket 17 and the outer side of the double armor plate 15. This allows the negative pressure tube 8 to bend and levitate after being supported. Furthermore, the elastic tension member 16 dampens the negative pressure tube 8, thereby reducing the friction between the test piece and the negative pressure tube 8. This prevents the friction between the negative pressure tube 8 and the test piece from intensifying and avoids damage to the weld points of the test piece caused by vibration. The damper 18 located at the bottom of the suspended bracket 17 can use its own air to play a damping role, absorb the impact of the suspended bracket 17, reduce the vibration of the suspended bracket 17, and further reduce the vibration of the negative pressure pipe 8.

[0035] Furthermore, a second support flange 19 is installed at the bottom of each damper 18 by screws. The second support flange 19 is installed inside the cabinet 1 by welding or bolting, so that each suspended bracket 17 uses a second support flange 19 of different lengths, causing the negative pressure pipe 8 to bend and be suspended.

[0036] See attached document Figure 2 and Figure 8 A third support flange 20 and a perforated plate 21 are connected vertically between the bottom surface of the suspended bracket 17 and the top of the damper 18. The third support flange 20 can be welded to the middle of the bottom of the suspended bracket 17 to play the role of central support. The top of the perforated plate 21 is welded to the third support flange 20, and the bottom is hinged to the damper 18, so that the negative pressure pipe 8 is supported along the axial direction of the damper 18. Inside the cabinet 1, a guide rod 22 is fixed by a nut, which passes through the hole of the perforated plate 21 to achieve horizontal limiting of the perforated plate 21. The guide rod 22 avoids the negative pressure pipe 8 to prevent squeezing the negative pressure pipe 8.

[0037] See attached document Figure 3 , Figure 9 and Figure 12 To provide negative pressure conditions, in this embodiment, an alloy gas pipe 23 is inserted through the bottom of the negative pressure pipe 8. The alloy gas pipe 23 is connected in sequence to the vacuum buffer tank 24 and the variable frequency fan 25. The variable frequency fan 25 is electrically connected to an external controller, which can directly control the start and stop of the variable frequency fan 25. When the variable frequency fan 25 starts, it draws out the air inside the vacuum buffer tank 24 to form a negative pressure environment. Simultaneously, the alloy air pipe 23 draws in the air inside the negative pressure pipe 8 to form negative pressure conditions, so that the negative pressure airflow in the negative pressure pipe 8 can flow from top to bottom.

[0038] See attached document Figure 10 , Figure 12and Figure 13 In order to monitor the vibration signal during the transport of the test piece, this embodiment also provides an internal controller 27 and an acceleration sensor 26 electrically connected to the internal controller 27 inside the cabinet 1. The acceleration sensor 26 can be a current output type acceleration sensor of the ULT02 series. The sensor uses an RS485 interface to transmit vibration signals. Accelerometer 26 is vertically bonded to the outside of outer sheath 10 to monitor the vibration signal of negative pressure tube 8; The internal controller 27 receives vibration signals and uses PID control to adjust the speed of the variable frequency fan 25. Based on the vibration signals, it controls the wind speed of the variable frequency fan 25 to keep the negative pressure airflow speed at 1.2 to 1.5 times the suspension speed of the test piece, maintaining the negative pressure stability (fluctuation within ±5%). The vibration speed of the negative pressure tube 8 is ≤10mm / s (permissible value according to ISO 10816 standard).

[0039] See attached document Figure 4 and Figure 5 In this embodiment, the detection area and the unloading area are divided to effectively avoid scratches caused by friction in the detection area when the test piece is unloaded. For example, the end of the negative pressure pipe 8 is connected to the discharge slide 28, and two distribution pipes 29 and two compressed air nozzles 30 pass through the outside of the discharge slide 28. The two feed pipes 29 are staggered, and the two compressed air nozzles 30 are respectively facing the two feed pipes 29. Since the compressed air nozzles 30 are connected in sequence to the nozzle solenoid valve, the air tank solenoid valve and the air compressor, which are electrically connected to the internal controller 27, the air compressor draws in and compresses the outside air and stores it in the air tank. When the nozzle solenoid valve and the air tank solenoid valve are opened, the compressed air nozzles 30 can spray compressed air. When the compressed air nozzle 30 at the top sprays air, it can blow defective products into the adjacent distribution pipe 29; When the compressed air nozzle 30 below sprays air, it can blow qualified products into the adjacent distribution pipe 29; This allows for the separate feeding of defective and qualified products without friction against the negative pressure pipe.

[0040] See attached document Figure 4 , Figure 5 and Figure 11 When the test piece leaves the distribution pipe 29, this embodiment uses a transfer platform 31 set outside the two distribution pipes 29 and a sponge pad 34 located inside the transfer platform 31 to assist in unloading. The soft sponge pad 34 absorbs the kinetic energy of the test piece, which can slow down the speed of the test piece's descent and will not damage the test piece, allowing the test piece to slide onto the discharge conveyor belt at a low speed. The inner wall of the transfer table 31 is provided with an inverted T-shaped groove 32 and a bearing plate 33 located inside the inverted T-shaped groove 32. Since the bearing plate 33 is bonded to the sponge pad 34, it can limit the sponge pad 34 and prevent the sponge pad 34 from falling off or tilting due to the impact of the test piece. Once the sponge pad 34 is worn to a certain extent, it can be pulled out along the inverted T-shaped groove 32 for easy replacement.

[0041] An industrial computer can be used as the external controller, while a Mitsubishi microcontroller can be used as the internal controller 27.

[0042] Example 2: like Figure 15 As shown, a method for detecting defects in electronic components includes the following steps: Feeding: A batch of test pieces are placed into the vibratory feeder 2. The vibration of the vibratory feeder 2 is used to transport the test pieces one by one, so that the test pieces slide one by one over the guide chute 3 and the feeding conveyor belt 4 until they enter the cabinet 1. Feeding: The servo motor 7 is controlled to rotate two limit rollers 6 to feed the test piece into the port of the negative pressure tube 8 and to separate the subsequent test pieces from the negative pressure tube 8, so as to feed the test pieces one by one. Negative pressure conditions: The external controller starts the variable frequency fan 25 to draw out the air inside the vacuum buffer tank 24 to form a negative pressure environment. At the same time, the alloy air pipe 23 draws in the air inside the negative pressure pipe 8 to form negative pressure conditions. The negative pressure airflow inside the negative pressure pipe 8 flows from top to bottom, so that the test piece moves in the air along the inside of the negative pressure pipe 8. There is almost no friction against the negative pressure pipe 8, which effectively reduces the scratches inside the device that block the test piece and greatly reduces the interference with the visual inspection results. Image sample acquisition: Images of the test piece are acquired from different angles inside the negative pressure tube 8 by at least four machine vision cameras 9 that penetrate the negative pressure tube 8. The images cover different sides of the test piece. The image signals are transmitted to the external controller through the I / O interface. At this time, the ISP algorithm preset by the external controller can identify defects in the image of the test piece. The image covers the side of the part under test, including at least the top, bottom, left and right sides of the part under test. The number of machine vision cameras 9 can also be increased to further acquire images of the front, back or edges of the part under test. Vibration control: The negative pressure tube 8 is opened along an elliptical path by the double armor plate 15 on the surface of the negative pressure tube 8 to maintain the shape of the negative pressure tube 8, and the negative pressure tube 8 is supported to bend and lift by the suspension bracket 17, the double armor plate 15 and the tension member 16. In addition, the elastic tension member 16 dampens the negative pressure tube 8 to reduce the friction between the test piece and the negative pressure tube 8. On the one hand, it prevents the friction between the negative pressure tube 8 and the test piece from intensifying, and on the other hand, it avoids the damage to the weld points of the test piece caused by vibration. At the same time, the damping effect of the damper 18 at the bottom of the suspended bracket 17 absorbs the impact of the suspended bracket 17, thereby reducing the vibration of the suspended bracket 17 and further reducing the vibration of the negative pressure pipe 8. Material feeding: The detection area and the feeding area are divided. The negative pressure pipe 8 is arranged in the detection area to effectively avoid friction between the detection area and the test piece during feeding. When the compressed air nozzle 30 at the top sprays air, it can blow defective products into the adjacent distribution pipe 29; When the compressed air nozzle 30 below sprays air, it can blow qualified products into the adjacent distribution pipe 29; This allows for the separate feeding of defective and qualified products without friction against the negative pressure pipe 8; Internal cleaning of the device: Stop the compressed air flow and feeding, spray a metered amount of atomized deionized water or 75% alcohol (isopropanol or ethanol) as a cleaning agent into the opening of the negative pressure pipe 8, and use the negative pressure air flow to clean the inner wall of the negative pressure pipe 8. 75% alcohol is preferred as it leaves less residue, but attention should be paid to anti-static treatment, such as contacting the negative pressure tube 8 with an ionized body during cleaning to neutralize static electricity.

[0043] In summary, this embodiment controls the suspended movement of the test piece through the above steps, quickly completing visual inspection. The inspection speed can reach more than 1000 pieces / min. After completing the visual inspection, the compressed airflow and feeding are stopped, a quantitative atomized cleaning agent is sprayed into the negative pressure tube, and the inner wall of the negative pressure tube is cleaned by the suction of the negative pressure airflow. There is little residue, cleaning is convenient, no need to add cleaning equipment, and it avoids inserting or puncturing the negative pressure tube 8, which is more user-friendly to the whole device.

[0044] The above description is merely an optional embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. An adaptive defect detection device for electronic components based on machine vision, characterized in that, include: Cabinet (1); The negative pressure tube (8) that transports the test piece under negative pressure conditions is provided inside the cabinet (1) for the negative pressure tube (8) to bend and levitate. When the test piece enters the cabinet (1), the port of the negative pressure tube (8) attracts the test piece, so that the test piece travels in the air along the inside of the negative pressure tube (8). Furthermore, the levitation mechanism dampens the negative pressure tube (8) to reduce friction between the test piece and the negative pressure tube (8); A machine vision camera (9) passes through the negative pressure tube (8) and is used to acquire images of the test piece inside the negative pressure tube (8).

2. The adaptive detection device for electronic component defects according to claim 1, characterized in that: The machine vision camera (9) is provided with an outer sheath (10) that wraps around the negative pressure tube (8), an inner lining (11) that penetrates the negative pressure tube (8) and the outer sheath (10), and an outer lining (13) that wraps around the outer sheath (10). The inner wall of the outer sheath (10) is fitted with an LED lamp head (12) that penetrates the negative pressure tube (8) and a glass liner (14). The glass liner (14) is used to separate the machine vision camera (9), the LED lamp head (12) and the device under test.

3. The adaptive detection device for electronic component defects according to claim 1, characterized in that, The levitation mechanism includes: A double-layered armor plate (15) is installed along the arc surface on the surface of the negative pressure tube (8), the double-layered armor plate (15) is used to maintain the shape of the negative pressure tube (8); A suspended bracket (17) is provided outside the negative pressure pipe (8), and a tension member (16) is connected between the inner wall of the suspended bracket (17) and the outer side of the compound armor plate (15). A damper (18) is located at the bottom of the suspended bracket (17), the damper (18) being used to reduce the vibration of the suspended bracket (17).

4. The adaptive detection device for electronic component defects according to claim 1, characterized in that: The end of the negative pressure pipe (8) is connected to the discharge chute (28), two distribution pipes (29) that pass through the outside of the discharge chute (28), and two compressed air nozzles (30). The two feed pipes (29) are staggered from each other, and the two compressed air nozzles (30) are respectively facing the two feed pipes (29).

5. The adaptive detection device for electronic component defects according to claim 1, characterized in that: The cabinet (1) is also equipped with a bearing frame (5) and two limiting rollers (6) installed at intervals inside the bearing frame (5). A transmission gear (601) is installed between one end of the two limiting rollers (6), and a servo motor (7) for driving the two limiting rollers (6) is installed on the outside of the bearing frame (5). When the servo motor (7) is working, the two limiting rollers (6) send the test piece into the port of the negative pressure tube (8) and separate the subsequent test pieces from the negative pressure tube (8), so as to realize the feeding of the test pieces one by one.

6. The adaptive detection device for electronic component defects according to claim 3, characterized in that: A third support flange (20) and a perforated plate (21) are connected vertically between the bottom surface of the suspended bracket (17) and the top surface of the damper (18). The perforated plate (21) connects the third support flange (20) and the damper (18). The cabinet (1) is fixed with a guide rod (22) that passes through the hole of the perforated plate (21), and the guide rod (22) avoids the negative pressure pipe (8).

7. The adaptive detection device for electronic component defects according to claim 2, characterized in that, The bottom of the negative pressure pipe (8) is connected to an alloy gas pipe (23), which is connected in sequence to a vacuum buffer tank (24) and a variable frequency fan (25). When the variable frequency fan (25) starts, the alloy air pipe (23) draws air from the inside of the negative pressure pipe (8) to form a negative pressure condition.

8. The adaptive detection device for electronic component defects according to claim 7, characterized in that: The cabinet (1) is also equipped with an internal controller (27) and an acceleration sensor (26) electrically connected to the internal controller (27). The accelerometer (26) is vertically mounted on the outside of the outer sheath (10) to monitor the vibration signal of the negative pressure tube (8); The internal controller (27) receives vibration signals and controls the wind speed of the variable frequency fan (25) according to the vibration signals.

9. The adaptive detection device for electronic component defects according to claim 4, characterized in that: Both of the two material distribution pipes (29) are equipped with a transfer table (31) on the outside and a sponge pad (34) inside the transfer table (31). The inner wall of the transfer table (31) is provided with an inverted T-shaped groove (32) and a support plate (33) located inside the inverted T-shaped groove (32), and the support plate (33) is connected to the sponge pad (34).

10. A method for detecting defects in electronic components, applied to the adaptive detection device for electronic component defects according to any one of claims 1-9, characterized in that, Includes the following steps: The test piece is placed in the vibratory plate (2), and the test piece is transported one by one by the vibration of the vibratory plate (2) until it enters the cabinet (1) and is sent into the negative pressure tube (8). A negative pressure airflow is formed inside the negative pressure tube (8), causing the test piece to travel in the air along the inside of the negative pressure tube (8), reducing the friction between the test piece and the negative pressure tube (8), so as to reduce the scratches on the test piece inside the device. At least four machine vision cameras (9) passing through the negative pressure tube (8) acquire images of the test piece from different angles inside the negative pressure tube (8). The image signals are transmitted to an external controller, and the external controller identifies defects in the test piece images through a preset algorithm. Open the negative pressure tube (8) to maintain its shape and support the pressure tube (8) to bend and lift it into the air. On the one hand, this prevents the friction between the negative pressure tube (8) and the test piece from intensifying, and on the other hand, it avoids damage to the weld joints of the test piece due to vibration. Divide the testing area and the unloading area, and place the negative pressure pipe (8) in the testing area to avoid friction between the test piece and the testing area when the test piece is unloaded in the unloading area; Control two compressed air streams to separately blow defective and qualified products; Stop the compressed airflow and feeding, spray a metered amount of atomized cleaning agent into the negative pressure pipe (8), and use the negative pressure airflow to clean the inner wall of the negative pressure pipe (8).

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