A fast and accurate pad repair method and apparatus

Abstract

The application belongs to the field of pad repair, and discloses a fast and accurate pad repair method and equipment, which comprises the following steps: providing a circuit board with a defective pad; importing a Gerber file of the circuit board into a computer to prepare for starting the repair work; marking a point; performing mechanical positioning (a probe) on the defective pad; performing visual positioning on the defective pad; performing secondary mechanical positioning (a printing head) on the defective pad; printing the pad; solidifying the pad; and trimming the appearance of the pad. The application adopts a three-positioning method, i.e., firstly positioning the position of the pad by using a mechanical pointer, and then performing secondary positioning by using a scanning camera component, so that the positioning accuracy can be effectively improved. The application has a fast pad repair speed, and the speed advantage is more prominent especially for the case of a larger area pad defect. The application uses an electronic additive manufacturing technology to repair the pad, so that the material waste can be reduced, and the application is very friendly to the environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to but is not limited to the technical field of pad repair, and particularly relates to a rapid and accurate pad repair method and device. BACKGROUND

[0002] Electronic assembly technology is a process of combining and interconnecting individual components (components, mechanical and electrical parts, structural parts, functional assemblies and modules, etc.) that make up a product to produce a complete product that meets the system technical requirements. With the development of electronic assembly technology towards miniaturization, high integration and high density, the number of components has increased significantly, and the reliability of electronic products has become increasingly prominent.

[0003] The reliability of the solder joint is one of the important factors affecting the reliability of the electronic assembly, and whether the solder joint can maintain good mechanical and electrical connection is crucial to the reliability of the electronic product. The structure of the solder joint mainly includes the solder pad, the solder, the lead pin and the substrate. The damage of the solder pad is easy to cause the unreliable connection of the solder joint, the falling off of the electronic component, the disconnection of the PCB wire and other problems, and is the main factor affecting the reliability of the solder joint. In the process of assembling or using the electronic product, the solder pad is affected by mechanical stress, such as improper force in the welding process, improper assembly installation or accidental operation in the product maintenance process. These mechanical stresses cause the solder pad to crack, deform, fall off or break. In addition, in harsh environmental conditions, the solder pad is corroded by chemicals or humidity, causing the solder pad surface to oxidize, corrode or lose weldability. This corrosion weakens the mechanical strength and reliability of the solder pad.

[0004] Currently, for a small number of pad defects on the PCB surface, technicians generally use electroplating pens to repair one by one. This manual pad repair method is time-consuming, difficult to operate and uncontrollable in precision. In addition, some pad automatic repair methods and devices are also disclosed: such as CN116896830A discloses a pad repair method, mainly including the following steps: (1) providing a ceramic substrate with defective pads, removing the defective pads on the ceramic substrate; (2) spin coating photoresist on the side of the ceramic substrate where the defective pads appear to form a first photoresist layer; (3) using a first drawing to perform first exposure and development on the ceramic substrate to obtain an opening of the defective pad; (4) baking the ceramic substrate to cure the first photoresist layer; (5) plating a metal film on the surface of the first photoresist layer; (6) spin coating photoresist on the metal film to form a second photoresist layer; (7) using a second drawing to perform second exposure and development on the ceramic substrate to obtain an opening of the defective pad; (8) baking the ceramic substrate to cure the second photoresist layer; electroplating the ceramic substrate to obtain a repaired pad; (9) removing the first photoresist layer, the second photoresist layer and the metal film on the ceramic substrate. Such as CN116845710B discloses a pad repair method and repair device based on a glass substrate. Including the following steps: (1) detecting and positioning the defective pad position; (2) pretreating the defective position; (3) printing a surrounding structure around the defective position and curing; (4) printing a repair slurry in the surrounding structure, curing and finishing to complete the pad repair.

[0005] In view of the above analysis, the technical problems existing in the prior art that need to be solved urgently are:

[0006] (1) The current pad automatic repair technology usually uses a scanning camera component to position the damaged pad once. Although this positioning method can locate the damaged position, the precision is not high (about ±50μm), which leads to a large deviation between the repaired pad and the original pad, affecting the secondary welding after repair.

[0007] (2) Many current pad repair technologies (such as CN116347783A "A PCB micro-sized pad scratch and falling repair method") take 2-3 hours to repair, which is relatively slow.

[0008] (3) Many current pad repair technologies (such as CN116896830A "A pad repair method") use copper plating, electroplating, etching and other processes. The chemical reagents required in the process will have adverse effects on the environment. SUMMARY

[0009] In view of the problems existing in the prior art, the present application provides a fast and accurate pad repair method and device.

[0010] The application is achieved in a quick and accurate pad repair method, which is characterized in that the quick and accurate pad repair method specifically comprises the following steps.

[0011] S1: providing a circuit board with a defective pad;

[0012] S2: importing the Gerber file of the circuit board into a computer and preparing to start the repair work;

[0013] S3: marking points;

[0014] S4: performing a mechanical positioning (probe) on the defective pad;

[0015] S5: performing visual positioning on the defective pad;

[0016] S6: performing a secondary mechanical positioning (print head) on the defective pad;

[0017] S7: pad printing;

[0018] S8: pad curing;

[0019] S9: pad appearance finishing.

[0020] Further, in S4, a specific mechanical positioning method is as follows:

[0021] S41: fixed screw positioning, mainly detecting whether the PCB is installed firmly;

[0022] S42: probe XY direction positioning, mainly determining the probe XY direction origin position;

[0023] S43: probe Z-axis direction positioning, mainly determining the probe Z direction origin position;

[0024] S44: bottom flatness detection, mainly detecting whether the equipment platform is flat;

[0025] S45: PCB flatness detection, mainly detecting whether the PCB surface is flat.

[0026] Further, in S5, a specific visual positioning method is as follows: the camera scans the Mark points marked in step S3 in the order of right upper, middle upper, left upper, left middle 1, left middle 2, right lower, middle lower, right lower, and right middle.

[0027] Further, in S6, a specific secondary mechanical positioning method is as follows:

[0028] S61. print head XY direction positioning, mainly determining the print head XY direction origin position;

[0029] S62. print head Z direction positioning, mainly determining the print head Z direction origin position.

[0030] Further, the S7 before the pad printing, also includes printing parameter debugging process, printing parameter debugging is mainly divided into two parts:

[0031] (1) height compensation debugging: mainly adjust the height of the printing head distance PCB surface;

[0032] (2) ink compensation adjustment: mainly adjust the amount of ink printing head.

[0033] Another purpose of the present application is to provide a kind of fast and accurate pad repair equipment, including pedestal 1, upper cover 2, printing platform 3, calibration component 4, debugging area 5, X axis 6, clamping component 7, print head 8, gas support 9, power switch 10, indicator light 11, emergency stop button 12.

[0034] Further, the positioning mechanism of the pad repair equipment includes camera 13, telescopic probe 14, print head 15, XY four quadrant limit stop 16, height limit stop 17.

[0035] In combination with the above technical solutions and the technical problems solved, the technical solutions protected by the present application have the following advantages and positive effects:

[0036] First, positioning accuracy is high: the present application adopts "three positioning method", first, use mechanical pointer to position the pad position, then use scanning camera component to position twice, which can effectively improve positioning accuracy;

[0037] Repair speed is fast: the present application has fast repair pad speed, especially for larger area pad defect, speed advantage is more prominent, has very obvious speed advantage;

[0038] Environment friendly: the present application uses electronic additive manufacturing technology to repair pad, which not only reduces material waste, but also is very friendly to environment.

[0039] Second, the technical solutions of the present application solve the technical problems that people have been eager to solve but have failed to obtain success:

[0040] In this age of electronic products, all electronic products are basically composed of electronic components and PCB, and the production and manufacturing process of PCB is a very high and very rigorous process, which is prone to cause PCB pad to fall off during production, maintenance, debugging and use. The traditional maintenance often uses fly line method, which greatly reduces the quality of PCB. Therefore, it is urgent to find a high-efficiency, low-cost and high-automation PCB pad repair method.

[0041] Currently, many experts and scholars have studied the methods of pad repair: Hou Keyu et al. used two layers of photoresist and a layer of metal film to repair imperfect pads, effectively reducing the scrap rate of products, however, this method requires the damaged pads to be completely removed before repair; Zhang Wei et al. developed a device that combines pad cleaning and other components, shortening the process flow and saving time and labor costs, but this method cannot accurately position the damaged pads, and all pads need to be repaired, which undoubtedly increases the repair time; Jixiong et al. used a subtractive manufacturing method of hydrofluoric acid etching to repair the pads, which can quickly and effectively repair the pads, but harmful gases such as ammonia and silicon tetrafluoride are produced during the process, causing environmental pollution. Therefore, the current pad repair methods mainly have the problems of long repair time, difficulty in accurate positioning, and unfriendly process environment.

[0042] Therefore, this paper proposes a fast and accurate pad repair method. This method not only has high positioning accuracy and can accurately repair damaged pads, but also has fast repair speed and friendly process environment, which greatly solves the long-anticipated but inefficient PCB pad repair problem in the industry.

[0043] Thirdly, the present application solves the problem of low positioning accuracy in the prior art. In traditional pad repair technology, visual positioning is usually relied on, which is difficult to meet the demand of high precision and is prone to cause the offset or incompleteness of the repaired pads, affecting the overall performance and service life of the circuit board. The present application introduces a combination of mechanical positioning, visual positioning and secondary mechanical positioning through the "three positioning method", which greatly improves the accuracy of pad repair and effectively avoids the error accumulation problem in traditional methods.

[0044] In industrial applications, the technical solution of the present application improves the accuracy of pad repair, especially suitable for the repair of precise circuit boards. This has significant application value for the manufacturing and maintenance of electronic products, especially in the fields of high-precision semiconductors, aerospace, medical equipment, etc. The present application can reduce the failure rate of pad repair, reduce the cost of product repair and maintenance for enterprises, and improve production efficiency and yield.

[0045] In addition, the present application also solves the problem of repair failure caused by inappropriate distance between the print head and the circuit board, excessive or insufficient ink output during the pad repair process through high compensation debugging and ink output compensation adjustment. This flexible parameter adjustment mechanism not only improves the quality of pad repair, but also can adapt to circuit boards of different thickness and material, increasing the applicability and application range of the technology.

[0046] The present application has obtained significant technical progress in industrial application, through high-precision pad positioning method and intelligent printing parameter debugging, the accuracy and success rate of pad repair are improved, the cost of manufacturing enterprises is significantly reduced, the quality and reliability of products are improved, and the technical upgrading and industrial development of electronic manufacturing industry are promoted. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a rapid and accurate pad repair method flowchart provided by the embodiment of the present application;

[0048] Figure 2 is a schematic diagram of the overall structure of the rapid and accurate pad repair device provided by the embodiment of the present application;

[0049] Figure 3 is a positioning mechanism structure schematic diagram of the rapid and accurate pad repair device provided by the embodiment of the present application;

[0050] Figure 4 is a repair effect schematic diagram provided by the embodiment of the present application;

[0051] Figure 5 is a repair accuracy schematic diagram provided by the embodiment of the present application;

[0052] In the figure: 1, base; 2, upper cover; 3, printing platform; 4, calibration component; 5, debugging area; 6, X axis; 7, clamping component; 8, printing head; 9, air support; 10, power switch; 11, indicator light; 12, emergency stop button; 13, camera; 14, telescopic probe; 15, printing head; 16, XY four-quadrant position limiter; 17, height position limiter. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present application clearer and more apparent, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0054] Application Example 1: Pad repair of high-precision electronic equipment

[0055] In the production of high-end electronic devices, such as smartphones and laptops, solder pads on circuit boards often become defective due to wear and tear during manufacturing or use, causing the devices to malfunction. The "three-stage positioning method" solder pad repair technology of this invention can be applied to the repair of solder pads in such precision electronic devices. Using this method, manufacturers can perform high-precision repair of defective solder pads during equipment production or rework, ensuring that the connection quality between the solder pads and components is not affected by the repair, thus avoiding malfunctions or shortened lifespan of the equipment. This application has significant value in the electronics manufacturing industry, especially in the high-end consumer electronics sector, and can greatly improve equipment reliability and customer satisfaction.

[0056] Application Example 2: Repairing solder pads on aerospace circuit boards

[0057] Circuit boards in aerospace equipment have extremely high requirements for the quality of solder pads. Even the slightest error can lead to equipment malfunction or even jeopardize flight safety. The solder pad repair method of this invention can be applied to circuit board maintenance in the aerospace field. When solder pads on a circuit board are damaged due to long-term use or external factors, repair using the high-precision "three-stage positioning method" of this invention ensures that the repaired solder pads are consistent with the original design, meet the stringent standards of the aerospace industry, reduce the risk of equipment failure due to solder pad defects, and improve the service life and safety of the equipment.

[0058] like Figure 1 As shown, this embodiment of the invention provides a fast and accurate method for repairing solder pads, which specifically includes:

[0059] S1: Provide circuit boards with defective solder pads;

[0060] S2: Import the Gerber file of the circuit board into the computer to prepare for the repair work;

[0061] S3: Mark the point;

[0062] S4: Perform a mechanical positioning (probe) on the defective pad;

[0063] S5: Visually locate defective pads;

[0064] S6: Perform secondary mechanical positioning on defective pads (print head);

[0065] S7: Pad printing;

[0066] S8: Pad hardening;

[0067] S9: Pad morphology trimming.

[0068] The prior art positioning of the defective pads is usually one positioning by using a camera, which results in low accuracy. The embodiment of the present application uses a "three-time positioning method" to position the defective pads.

[0069] In the S4, a specific mechanical positioning method is as follows:

[0070] S41: fixed screw positioning, mainly detecting whether the PCB is firmly installed;

[0071] S42: probe XY direction positioning, mainly determining the XY direction origin position of the probe;

[0072] S43: probe Z axis direction positioning, mainly determining the Z direction origin position of the probe;

[0073] S44: bottom flatness detection, mainly detecting whether the equipment platform is flat;

[0074] S45: PCB flatness detection, mainly detecting whether the PCB surface is flat.

[0075] In the S5, a specific visual positioning method is as follows: the camera scans the Mark points in the order of right upper, middle upper, left upper, left middle 1, left middle 2, right lower, middle lower, right lower, and right middle.

[0076] In the S6, a specific secondary mechanical positioning method is as follows:

[0077] S61: printing head XY direction positioning, mainly determining the XY direction origin position of the printing head;

[0078] S62: printing head Z direction positioning, mainly determining the Z direction origin position of the printing head.

[0079] In the S7, before the pad printing, a printing parameter debugging process is further included, which mainly includes two parts:

[0080] (1) height compensation debugging: mainly adjusting the height of the printing head from the PCB surface. If the height is too high, the printing accuracy will be reduced; if the height is too low, the printing needle will smear the ink on the circuit board to other places, and ink marks will be formed in the middle.

[0081] (2) ink discharge compensation adjustment: mainly adjusting the ink discharge amount of the printing head. If the ink discharge amount is too large, the pad will become large, which will affect the accuracy; if the ink discharge amount is too small, the ink discharged by the printing head cannot form a complete pad.

[0082] The fast and accurate pad repair method of the embodiment of the present application improves the accuracy of pad repair through the "three positioning method", solving the problem of low positioning accuracy in the prior art. First, in the S4 step, the probe is positioned on the circuit board through one-time mechanical positioning, including fixed screw positioning, probe XY and Z axis direction positioning, equipment platform and PCB flatness detection. This step ensures that the circuit board is stable, the axes of the probe are accurately positioned, and the platform and flatness meet the requirements, thereby laying a foundation for subsequent visual positioning and printing operation.

[0083] Then, in the S5 step, the camera scans the Mark points on the circuit board in a predetermined order to complete the visual positioning. Scanning through multiple positions of Mark points can more accurately determine the specific position of the pad, making up for the deficiency of mechanical positioning. This step ensures that the pad position is accurately captured, reduces positioning errors, and ensures the accuracy of the next printing.

[0084] In the S6 step, secondary mechanical positioning is performed, mainly positioning the XY and Z directions of the printing nozzle. By accurately positioning the position of the printing nozzle, the correct position of the printing head in the pad area is ensured, thereby avoiding misalignment or deviation during printing. The secondary positioning further improves the accuracy of the operation and provides a guarantee for the accuracy of printing.

[0085] Finally, before the S7 pad printing, the system performs printing parameter debugging. This debugging mainly includes height compensation and ink output compensation adjustment. Height compensation debugging ensures that the printing head maintains an appropriate distance from the PCB surface, avoiding precision loss or ink diffusion; ink output compensation adjustment adjusts the output amount of ink to ensure that the printing head outputs an appropriate amount of ink to form a complete pad. These detailed adjustments ensure high precision and high quality in the pad repair process.

[0086] As shown in Figure 2 The fast and accurate pad repair device provided by the embodiment of the present application includes a base 1, an upper cover 2, a printing platform 3, a calibration component 4, a debugging area 5, an X-axis 6, a clamping component 7, a printing head 8, an air support 9, a power switch 10, an indicator light 11, and an emergency stop button 12.

[0087] The positioning mechanism structure diagram of the pad repair device is as shown in Figure 3 It includes a camera 13, a telescopic probe 14, a printing head 15, an XY four-quadrant position limiter 16, and a height position limiter 17.

[0088] The working principle of the fast and accurate pad repair device is as follows:

[0089] Firstly, the base 1 of the device serves as the support structure of the entire apparatus, on which multiple key components are installed. The upper cover 2 is connected to the base 1 by air support 9, ensuring that the device can be easily opened and closed during operation, providing protection for the internal components. The printing platform 3 is installed in the central area of the base 1, serving as the main working area for pad repair, responsible for carrying the pads or circuit boards to be repaired.

[0090] Secondly, the calibration component 4 and the debugging area 5 of the device are installed on one side of the printing platform 3, respectively, for accurate calibration and testing of the device before repairing the pads. The X-axis 6 is connected to the bottom of the printing platform 3, used to control the left and right movement of the clamping component 7 and the print head 8, ensuring accurate positioning during the repair process. The XY four-quadrant position limiter 16 limits the range of movement of the print head 15 during the repair process by being fixed on the printing platform 3, to avoid exceeding the printing area.

[0091] Then, the clamping component 7 is used to fix the circuit board to be repaired, ensuring that it does not move during the repair process. The print head 15 is connected to the clamping component 7 through the X-axis 6 and can move flexibly in XYZ three directions, cooperating with the telescopic probe 14 and the height limiter 17, to achieve accurate repair of the pads. The height limiter 17 is installed on the print head 15, used to control the distance between the print head 15 and the circuit board, to ensure the height consistency of the pads during the repair process.

[0092] Finally, the camera 13 is installed above the base 1 through the connecting bracket, responsible for monitoring every detail of the repair process and feeding back the images to the operator. The power switch 10, indicator light 11 and emergency stop button 12 are installed on one side of the base 1, respectively, used to control the start of the device, display the running state and stop operation in emergency situations, ensuring the safety and reliability of the device during use.

[0093] The repair effect of the embodiment of the present application is as shown in Figure 4 . Figure 4 (a) Two small area defects appeared in the center position of the pad, and after repair, the effect is as shown in Figure 4 (b). Figure 4 (c) A larger area of the pad appeared in the lower right corner of the defect, Figure 4 (d), which was perfectly repaired.

[0094] To demonstrate the technical advantage of "high repair precision" of the embodiment of the present application, the distance between the pad and the reference point before and after repair of two groups is compared to measure the positioning accuracy of the pad repair, as shown in Figure 5 . Figure 5 (a) shows that the distance between the first group of damaged pads and the reference line before repair is 1.006mm, Figure 5(b) shows that the distance between the first group of repaired pads and the reference line is 1.002 mm, and the repair accuracy is about 4 μm. Figure 5 (c) shows that the distance between the second group of damaged pads and the reference line is 1.596 mm before repair, Figure 5 (d) shows that the distance between the second group of repaired pads and the reference line is 1.600 mm, and the repair accuracy is about 4 μm. It can be seen that the pad positioning accuracy of the embodiment of the present application is high, about 4-5 μm, which is significantly improved compared with the current pad repair accuracy (about ± 50 μm).

[0095] To demonstrate the technical advantage of "fast repair speed" of the embodiment of the present application, the time required for repairing 25, 50, 100, 150 and 200 pads is recorded as shown in Table 1. Currently, many pad repair technologies have a long repair time, for example, the method mentioned in CN116347783A "A method for repairing micro-sized damaged and fallen pads on a PCB" takes about 1 hour for one step of front side lithography. The entire process of the embodiment of the present application takes no more than 30 minutes when repairing 200 pads, which greatly improves the efficiency. In addition, the more the number of pads to be repaired, the less significant the increase in repair time of the embodiment of the present application. It can be seen that the embodiment of the present application has more prominent advantages for large-area pad repair.

[0096] Table 1 Repair time of different number of pads

[0097] Number of pads 25 50 100 150 200 Time 19 min 35 sec 21 min 57 sec 25 min 9 sec 28 min 27 sec 29 min 44 sec

[0098] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any modification, equivalent replacement and improvement made by those skilled in the art within the technical range disclosed by the present application, which is within the spirit and principles of the present application, should be covered within the protection scope of the present application.

Claims

1. A fast and accurate pad repair method, characterized in that, The method specifically comprises: S1: providing a circuit board with a defective pad; S2: importing the Gerber file of the circuit board into a computer, and preparing to start the repair work; S3: marking a point; S4: performing mechanical positioning on the defective pad once; S5: performing visual positioning on the defective pad; S6: performing mechanical positioning on the defective pad twice; S7: pad printing; S8: pad solidification; S9: pad appearance finishing; In the S4, a specific mechanical positioning method once is as follows: S41: fixed screw positioning, mainly detecting whether the PCB is installed firmly; S42: telescopic probe XY direction positioning, mainly determining the XY direction origin position of the telescopic probe; S43: telescopic probe Z axis direction positioning, mainly determining the Z direction origin position of the telescopic probe; S44: bottom flatness detection, mainly detecting whether the equipment platform is flat; S45: PCB flatness detection, mainly detecting whether the PCB surface is flat; In the S6, a specific mechanical positioning method twice is as follows: S61: printing nozzle XY direction positioning, mainly determining the XY direction origin position of the printing nozzle; S62: printing nozzle Z direction positioning, mainly determining the Z direction origin position of the printing nozzle.

2. The method of claim 1, wherein the method is performed in a time period of less than 1 minute. In the S5, a specific visual positioning method is that the camera scans the Mark point marked in the step S3 in the order of right upper, middle upper, left upper, left middle 1, left middle 2, right lower, middle lower, right lower, and right middle.

3. The method of claim 1, wherein the method is performed in a time period of less than 1 minute. Before the S7, the pad printing further comprises a printing parameter debugging process, which mainly includes two parts: (1) height compensation debugging: mainly adjusting the height of the printing nozzle from the PCB surface; (2) ink output compensation adjustment: mainly adjusting the ink output of the printing head.

4. A pad repair apparatus for the rapid and accurate pad repair method according to any one of claims 1 to 3, comprising a base (1) and an upper cover (2), characterized in that, The upper cover (2) is connected with the base (1) through the air support (9), which can be easily opened and closed during operation, and provides protection for the internal components.

5. The pad repair apparatus of claim 4, wherein The device comprises a calibration component (4) and a debugging area (5) installed on one side of the printing platform (3), and an X axis (6) connected at the bottom of the printing platform (3) for controlling the left and right movement of the clamping component (7) and the printing head (15), and limiting the movement range of the printing head (15) through the XY four-quadrant limit stopper (16) installed on the printing platform (3), so as to ensure the accurate positioning in the repair process.

6. The pad repair apparatus of claim 4, wherein The printing head (15) of the device is connected with the clamping component (7) through the X axis (6), and is equipped with a telescopic probe (14) and a height limit stopper (17) to realize accurate repair of the pad, and the camera (13) is installed above the base (1) to monitor the details in the repair process, and the image is fed back to the operator in real time through the display screen.

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