A test board, detection system and method for detecting uniformity of soldering flux

Abstract

The present invention belongs to the field of wave soldering technology, and in particular relates to a test board, a detection system, and a detection method for detecting the uniformity of flux. A plurality of electrode points are provided on the bottom of the test board, and the plurality of electrode points are arranged in a plurality of rows and columns in the form of an array on the bottom of the board. The detection system includes a test board and a data detection module, which is electrically connected to the test board. The data detection module detects the AD values ​​of all electrode points after the flux is coated; and a data analysis module judges the uniformity of the flux on the test board according to the AD values ​​detected by the data detection module. After the test board is subjected to flux coating treatment in a wave soldering device, the detection method includes: obtaining the AD values ​​of all electrode points, and judging the uniformity of the flux on the test board according to the AD values. The present invention judges the uniformity of flux spraying by detecting the trend of changes in the electrical parameters of the standard test board after the flux is sprayed, and the detection result is more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of wave soldering, and in particular relates to a test board, a detection system and a method for detecting uniformity of soldering flux. Background Art

[0002] In wave soldering technology, the amount of flux applied is critical. Too little flux can lead to poor soldering, such as poor soldering or tinning. Excessive flux, if not cleaned, can easily dissociate into mobile ions under certain temperature and humidity conditions. The movement of these ions under the action of an electric field causes electrochemical corrosion and electromigration, which in turn corrodes the solder joints and PCBs. In severe cases, this can lead to loose solder joints and circuit board failure. Cleaning increases production costs and reduces efficiency. Furthermore, uneven flux application can lead to numerous soldering defects. Therefore, the production process requires a very uniform flux spray, with less flux in some areas and more in others.

[0003] At present, the industry uses fax paper to pass through the flux spraying area to judge the uniformity of the flux, such as Figure 1 As shown in the figure, the uniformity of flux application is determined manually by viewing the developed image on the fax paper after spraying. This method relies entirely on the subjective judgment of the employee's personal experience, and the results vary from person to person, so specific quantitative data cannot be provided.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a flux uniformity detection device, detection method and system. The present invention judges the flux spraying uniformity by detecting the changing trend of the electrical parameters of the standard test board after flux spraying, and the detection result is more accurate.

[0006] In order to solve the above technical problems, the present invention proposes a test board for detecting the uniformity of soldering flux, which is characterized in that:

[0007] A plurality of electrode points are provided on the bottom of the test board, and the plurality of electrode points are arranged in a plurality of rows and columns in an array on the bottom of the board.

[0008] Further optionally, among the multiple electrode points located in the same row, the intervals between the multiple electrode points on both sides of the bottom of the board are smaller than the intervals between the multiple electrode points in the middle of the bottom of the board.

[0009] Further optionally, the intervals between any two of the plurality of electrode points in the same column are equal.

[0010] Further optionally, each of the electrode points includes two positive and negative electrodes, and the interval between the two electrodes is 0.4 to 0.6 mm.

[0011] The present invention also proposes a detection system for detecting the uniformity of soldering flux, the detection system comprising the test board according to any one of claims 1 to 4, and further comprising

[0012] A data detection module is electrically connected to the test board, and the data detection module detects the AD values ​​of all the electrode points after the electrode points are coated with flux;

[0013] The data analysis module determines the uniformity of the soldering flux on the test board according to the AD value detected by the data detection module.

[0014] Further optionally, the test plate is divided into a plurality of detection areas, and a plurality of the electrode points are distributed in each detection area;

[0015] The data detection module detects the AD values ​​of a set number of electrode points in a preset number of detection areas respectively;

[0016] The data analysis module judges the flux uniformity of each detection area based on a set number of AD values ​​in a preset number of detection areas; when the flux uniformity of all the preset number of detection areas is judged to be qualified, the flux uniformity of the test board is judged to be qualified; when the flux uniformity of any one of the preset number of detection areas is judged to be unqualified, the flux uniformity of the test board is judged to be unqualified.

[0017] Further optionally, the detection system further includes a data processing module,

[0018] The data detection module detects the AD value of each electrode point at set intervals;

[0019] The data processing module obtains multiple AD values ​​of each electrode point, selects the largest n values, and calculates the average value of the largest n values ​​as the AD determination value of each electrode point;

[0020] The data analysis module obtains the maximum AD determination value and the minimum AD determination value of each detection area in a preset number of detection areas, and calculates the average AD determination value of each detection area; calculates a first deviation of the maximum AD determination value relative to the average AD determination value, and a second deviation of the minimum AD determination value relative to the average AD determination value; compares the first deviation, the second deviation and the set deviation respectively, and when the first deviation and the second deviation are less than or equal to the set deviation, determines that the flux uniformity of the corresponding detection area is qualified; when the first deviation or the second deviation is greater than the set deviation, determines whether the flux uniformity of the corresponding detection area is qualified according to the difference between the maximum AD determination value and the minimum AD determination value;

[0021] The first deviation=(maximum AD determination value-average AD determination value) / average AD determination value, and the second deviation=(average AD determination value-minimum AD determination value) / average AD determination value.

[0022] Further optionally, when it is determined that the first deviation or the second deviation is greater than a set deviation,

[0023] The data analysis module further calculates a difference between the maximum AD determination value and the minimum AD determination value, and a maximum allowable difference, and compares the difference between the maximum AD determination value and the minimum AD determination value with the maximum allowable difference; when the difference between the maximum AD determination value and the minimum AD determination value is less than or equal to the maximum allowable difference, the soldering flux uniformity of the corresponding inspection area is determined to be qualified; otherwise, the soldering flux uniformity of the corresponding inspection area is determined to be unqualified;

[0024] The maximum allowable difference is: a set multiple of the average AD determination value, and the set multiple is less than 1.

[0025] Optionally, further comprising

[0026] A display module displays a three-dimensional graph of the AD values ​​of all electrode distribution points and / or a curve showing the AD values ​​of all electrode distribution points changing with time.

[0027] Further optionally, the detection system further includes a protection box, the data detection module is located in the protection box, and the protection box is a high-temperature resistant and heat-insulating protection box.

[0028] The present invention also proposes a method for detecting the uniformity of soldering flux using any one of the test boards described above, wherein the test board is subjected to a soldering flux coating process in a wave soldering device, and the method comprises:

[0029] The AD values ​​of the electrode distribution points are obtained, and the uniformity of the soldering flux on the test board is judged according to the AD values.

[0030] Further optionally, the test board is divided into a plurality of detection areas, and a plurality of electrode points are distributed in each of the detection areas; the AD values ​​of the electrode points are obtained, and the uniformity of the flux on the test board is judged according to the AD values, including

[0031] Obtaining AD values ​​of a set number of electrode points within a preset number of detection areas on the test plate;

[0032] The uniformity of the flux in each detection area is determined based on the AD values ​​of a set number of electrode points in a preset number of detection areas;

[0033] When the flux uniformity of all the preset number of detection areas is qualified, the flux uniformity on the test board is determined to be qualified; when the flux uniformity of any one of the preset number of detection areas is unqualified, the flux uniformity on the test board is determined to be unqualified.

[0034] Further optionally, the method of judging the uniformity of the flux in each detection area according to the AD values ​​of a set number of electrode points in a preset number of detection areas includes:

[0035] Obtain multiple AD values ​​for each electrode point, select the largest n values, and then calculate the average of the largest n values ​​as the AD judgment value for each electrode point;

[0036] Obtaining a maximum AD determination value and a minimum AD determination value of each detection zone in a preset number of detection zones, and calculating an average AD determination value of each detection zone;

[0037] calculating a first deviation of the maximum AD determination value relative to the average AD determination value, and a second deviation of the minimum AD determination value relative to the average AD determination value;

[0038] Comparing the first deviation and the second deviation with the set deviation respectively; when the first deviation and the second deviation are less than or equal to the set deviation, determining that the flux uniformity of the corresponding inspection area is qualified; when the first deviation or the second deviation is greater than the set deviation, determining whether the flux uniformity of the corresponding inspection area is qualified according to the difference between the maximum AD judgment value and the minimum AD judgment value;

[0039] The first deviation=(maximum AD determination value-average AD determination value) / average AD determination value, and the second deviation=(average AD determination value-minimum AD determination value) / average AD determination value.

[0040] Further optionally, judging whether the soldering flux uniformity of the detection area is qualified according to the difference between the maximum AD judgment value and the minimum AD judgment value includes:

[0041] Calculating a difference between the maximum AD determination value and the minimum AD determination value, and a maximum allowable difference;

[0042] Comparing the difference between the maximum AD determination value and the minimum AD determination value with the maximum allowable difference; when the difference between the maximum AD determination value and the minimum AD determination value is less than or equal to the maximum allowable difference, determining that the flux uniformity of the corresponding inspection area is qualified; otherwise, determining that the flux uniformity of the corresponding inspection area is unqualified;

[0043] The maximum allowable difference is a set multiple of the average AD determination value, and the set multiple is less than 1.

[0044] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:

[0045] The present invention develops a standard flux test board, and performs flux spraying on the standard test board with the same public parameters as the actual product in a wave soldering device. Then, the uniformity of the flux spraying is judged by detecting the changing trend of the electrical parameters of the standard test board after flux spraying, replacing the traditional manual visual judgment, and the judgment result is more accurate.

[0046] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0048] Figure 1 : Comparison of the development effects of qualified and unqualified flux uniformity after conventional flux spraying on fax paper.

[0049] Figure 2 : is a bottom view of a test board according to an embodiment of the present invention.

[0050] Figure 3 : A diagram of the test board surface according to an embodiment of the present invention.

[0051] Figure 4 : This is a layout diagram of the electrode points on the test board according to an embodiment of the present invention.

[0052] Figure 5 : A diagram showing the spray trajectory of the soldering flux according to an embodiment of the present invention when passing through a test board.

[0053] Figure 6: is an electrode model diagram of an embodiment of the present invention.

[0054] Figure 7 : A detection system diagram of an embodiment of the present invention.

[0055] Figure 8 : A schematic diagram of the partitions of the test board according to an embodiment of the present invention.

[0056] Figure 9 : A three-dimensional image comparison of qualified and unqualified soldering flux uniformity of the test board according to the embodiment of the present invention.

[0057] Figure 10 : is the flux volatilization curve of each electrode point of the test board of the embodiment of the present invention.

[0058] Figures 11 to 14 : is a flow chart of the detection method of an embodiment of the present invention.

[0059] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0060] In the description of the present invention, it should be noted that the terms "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0061] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," "in contact," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0062] The existing technology for judging the uniformity of solder flux uses fax paper to pass through the solder flux spraying area, such as Figure 1As shown, by checking the developed image of the fax paper after spraying, the uniformity of the flux spraying is manually judged. The judgment result of this method depends entirely on the subjective judgment of the employee's personal experience. The judgment results vary from person to person, and no specific quantitative data can be given. The accuracy of the judgment cannot be guaranteed. This embodiment proposes a test board for detecting the uniformity of the flux. Since the standard process test board is a carrier for testing various process parameters, it must be universal. Using it to test can reflect the actual production conditions of various products. According to research, after a large number of simulations and verifications on the test board size, board thickness determination, board selection, sampling point layout, test package design, etc., a standard test board as shown in the figure below was designed to provide a test carrier for the subsequent wave soldering parameter test.

[0063] The bottom of the test board of this embodiment is provided with a plurality of electrode points, and the plurality of electrode points are arranged in a plurality of rows and columns in the form of an array on the bottom of the board. Figure 2 and Figure 3 As shown, the test board of this embodiment is a PCB board, and the size of the actual product is simulated, for example, the size is 240mm*100mm, and the electrode distribution distance is as follows Figure 4 As shown, among the multiple electrode points located in the same row, the intervals between the multiple electrode points on both sides of the bottom of the board are smaller than the intervals between the multiple electrode points in the middle of the bottom of the board, and the intervals between the multiple electrode points in the same column are equal. The reason for adopting such a design for the electrode points is that when the PCB board passes through the wave soldering chamber, the shape and spray speed of the flux spray on both sides of the PCB board are greatly affected by the PCB board, so the spacing between the electrode points on both sides is reduced to make the test more accurate. According to the shape of the spray, chain speed, spray speed, and the starting point of the spray at the PCB board, the spray trajectory effect (trajectory production) is as follows Figure 5 shown.

[0064] Further optionally, each electrode arrangement includes two positive and negative electrodes, and the interval between the two electrodes is 0.4 to 0.6 mm. Each electrode arrangement is made into a two-electrode model such as Figure 6 The distance between the two electrodes is 0.4-0.6 mm, preferably 0.5 mm, so as to minimize the error of the AD value of the detection electrode arrangement. In a specific embodiment, the height of the two electrodes is 3 mm, the width of the electrodes is 0.5 mm, and the spacing between the electrodes is 0.5 mm.

[0065] This embodiment also provides a detection system for detecting flux uniformity. The detection system includes any of the test boards described above. The detection system of this embodiment also includes a data detection module and a data analysis module. The data detection module is electrically connected to the test board and detects the AD values ​​of all electrode points after flux coating. The data analysis module determines the uniformity of the flux on the test board based on the AD values ​​detected by the data detection module.

[0066] When conducting flux uniformity testing, the test board simulates the actual product passing through the wave soldering chamber. Since the flux will volatilize during the subsequent preheating process after being coated on the electrode points, the AD value of the electrode points needs to be tested immediately after the flux is sprayed on the electrode points. Therefore, the data detection module needs to be electrically connected to the test board and then enter the wave soldering chamber at the same time. The high temperature environment inside the wave soldering chamber is as high as 270 degrees. Under current technical conditions, the data detection module cannot work normally at such a high temperature. This puts higher requirements on the anti-interference, high temperature resistance and stability of the data detection module. The detection system of this embodiment also includes a protection box. The data detection module is located in the protection box. The protection box is a high temperature resistant and heat-insulating protection box, thereby ensuring the reliability of data detection by the data detection module in a high temperature environment. In a specific embodiment, the test board adopts a 6-layer double-sided PCB board design. The protection and data detection module made of high temperature heat-insulating material is located in the protection box, achieving the effect of being overall compact, high temperature resistant and having strong anti-interference ability. At the same time, the test board and the data detection module are connected by FPC soft cables, which eliminates the data confusion caused by manual wiring errors and improves the reliability of the controller.

[0067] The test board of this embodiment simulates an actual product passing through a wave soldering chamber and does not undergo a wave soldering process using liquid tin after flux spraying, so that the test board can be reused.

[0068] The detection system of this embodiment also includes a data transmission module. The data detected by the data detection module in this embodiment is transmitted through the data transmission module in a variety of data transmission modes, such as by setting a USB data interface, a wireless communication interface, an SD card storage interface, etc. to perform data transmission. The detection system of this embodiment also includes a timing module. The timing module is used to determine the collection interval. The data detection module collects the AD value of the electrode distribution point once every set time according to the collection interval determined by the timing module. The detection system also includes a system trigger module, which is used to control the start and end of the data detection of the data detection module. The detection system also includes a power supply module, which is used to power each module. The power supply module can optionally be powered by a battery. In a specific embodiment, the data detection module, the data transmission module, the timing module, the system trigger module and the power supply module are integrated, such as Figure 7 As shown, the modules are integrated to form a controller housed in a protective box. When a test board passes through the wave soldering chamber, it enters the chamber simultaneously with the test board. After flux is sprayed onto the electrode points on the bottom of the test board, the data detection module in the controller checks the AD values ​​of each electrode point at set intervals. After the test board completes the simulated operation within the wave soldering chamber, the detected data is transmitted to graphical software, which then analyzes the collected data to determine if the flux spraying uniformity is acceptable.

[0069] The core of graphical software development in this embodiment lies in the design of software algorithms. The greatest challenge in software development is expressing process experience through software. Through modeling and denoising, combined with the assistance of various mathematical analysis tools, process experience is successfully abstracted into mathematical algorithms. These algorithms are then converted into a series of mathematical expressions and written into graphics processing software. After importing test data into the graphics software, process parameters are graphically displayed, and the results are automatically analyzed and judged.

[0070] The following is a specific implementation of the data analysis of this embodiment:

[0071] First, open the user software. The software will automatically send a hardware calibration command to confirm whether the hardware connection is correct. There may be two situations at this time: "Connection Successful" and "Connection Failed". If the computer is already properly connected to the hardware and the time calibration is successful before opening the software: - The corresponding area of ​​the window will prompt "Connection Successful" and the software graphics window function module will display the following status A.

[0072]

[0073] If the computer is connected to the hardware before opening the software but the time calibration fails, or if the computer is not connected to the hardware before opening the software, a "Connection Failed" message will be displayed. The software's graphical window function module will display the following state B, and the manual "Connect" button will appear black (valid). Note: In state B, you can click the "Manual Connect" button to attempt a manual connection. If the connection is successful, the graphical window will switch to state A; otherwise, it will remain in state B.

[0074]

[0075] Then synchronize the files and data, and the window is configured with "Synchronize Files" and "Get Synchronized Data" buttons. Before synchronizing files, you must first configure the environmental information (base, workshop, line, chain speed) when testing data to facilitate data distinction, otherwise the file cannot be obtained. The synchronize file button is invalid. After the configuration is completed, click on the synchronize file, and the window will display the name of the read data file. After all file names are synchronized, the synchronize data button function will be valid. Select any file name under the synchronized file and double-click to start getting the synchronized file data. At the same time, the window will pop up the data synchronization progress display. After the file data synchronization is completed, the corresponding synchronization completion prompt will be displayed. At the same time, the data is automatically recorded in the database. If the physical connection is disconnected or the communication fails during this process, a communication timeout will occur, and the window should give a relevant prompt.

[0076] Finally, for data analysis, click the query button. The graphical interface switches to the query data window, which displays the 10 most recent documents. There should also be input boxes and query buttons for searching by "base," "workshop," "line," and "date." Double-clicking the corresponding file name will directly pop up the "Generate Chart" interface.

[0077] The test board is divided into multiple detection areas, and multiple electrode points are distributed in each detection area; the data detection module respectively detects the AD values ​​of a set number of electrode points in a preset number of detection areas; the data analysis module judges the flux uniformity of each detection area based on the AD values ​​of a set number of detection areas in a preset number; when the flux uniformity of all the detection areas of the preset number is judged to be qualified, the flux uniformity of the test board is judged to be qualified; when the flux uniformity of any one of the detection areas of the preset number is judged to be unqualified, the flux uniformity of the test board is judged to be unqualified.

[0078] In a specific embodiment, Figure 8 As shown, there are 128 electrode points on the test board. The 128 points are divided into zones. The 16 points in the two columns on the left are used as the left plate detection zone, the 16 points in the two columns on the right are used as the right plate detection zone, and the rest are divided into the middle of the board as the middle detection zone. Numerical analysis is performed on each zone. When the uniformity of all detection zones is qualified, the flux uniformity of the entire test board is qualified. As long as the uniformity of one of the detection zones is unqualified, the flux uniformity of the entire test board is unqualified. The tester can arbitrarily partition the test board as needed. The number of electrode points in each test zone and the number and position of the test zones are not limited in this embodiment.

[0079] The detection system also includes a data processing module, which detects the AD value of each electrode distribution point at set intervals; the data processing module obtains multiple AD values ​​of each electrode distribution point, selects the largest n values, and then calculates the average of the largest n values ​​as the AD judgment value of each electrode distribution point; the data analysis module obtains the maximum AD judgment value and the minimum AD judgment value of each detection area in a preset number of detection areas, and calculates the average AD judgment value of each detection area; calculates the first deviation of the maximum AD judgment value relative to the average AD judgment value, and the second deviation of the minimum AD judgment value relative to the average AD judgment value; compares the first deviation, the second deviation and the set deviation respectively, and when the first deviation and the second deviation are less than or equal to the set deviation, determines that the flux uniformity of the corresponding detection area is qualified; when the first deviation or the second deviation is greater than the set deviation, determines whether the flux uniformity of the corresponding detection area is qualified according to the difference between the maximum AD judgment value and the minimum AD judgment value; wherein, the first deviation = (maximum AD judgment value - average AD judgment value) / average AD judgment value, the second deviation = (average AD judgment value - minimum AD judgment value) / average AD judgment value.

[0080] The set deviation can be set to 1%. Taking the left detection area as an example, if the deviation between the maximum AD determination value and the average AD determination value, and the deviation between the minimum AD determination value and the average AD determination value, of the 16 points in the left detection area are both within 1%, it indicates good uniformity. If either the deviation between the maximum AD determination value and the average AD determination value, or the deviation between the minimum AD determination value and the average AD determination value, of the 16 points in the left detection area exceeds 1%, it indicates that the uniformity may be poor and further evaluation is required to confirm the uniformity.

[0081] Further optionally, when it is judged that the first deviation or the second deviation is greater than the set deviation, the data analysis module also calculates the difference between the maximum AD judgment value and the minimum AD judgment value, and the maximum allowable difference, and compares the difference between the maximum AD judgment value and the minimum AD judgment value with the maximum allowable difference; when the difference between the maximum AD judgment value and the minimum AD judgment value is less than or equal to the maximum allowable difference, the flux uniformity of the corresponding detection area is judged to be qualified, otherwise the flux uniformity of the corresponding detection area is judged to be unqualified; the maximum allowable difference is a set multiple of the average AD judgment value, and the set multiple is less than 1. Optionally, the value range of the set multiple is 0.02~0.06, preferably 0.05.

[0082] Further optionally, a display module is also included, which displays a three-dimensional graph of the AD values ​​of all electrode distribution points and / or a curve of the AD values ​​of all electrode distribution points changing with time.

[0083] This embodiment uses 3D drawing tools, such as Matlab, to display the values ​​in three-dimensional graphics, such as Figure 9 As shown in the figure, the X and Y axes represent the distribution of each electrode point on the test board, and the Z axis represents the AD judgment value of each electrode point after flux sampling. By displaying the AD values ​​of all electrode points in a three-dimensional graph, it is possible to more intuitively see whether the flux uniformity on the test board is qualified, thus assisting testers in judging flux uniformity.

[0084] In addition, since the flux will gradually evaporate over time, if there is a lot of flux, its AD value will be relatively large and the volatilization time will be relatively long. Conversely, if there is less flux, its AD value will be relatively small and the volatilization time will be relatively short, which in turn reflects the amount of flux at each point from the side. Therefore, this embodiment can also draw a flux volatilization curve with time as the horizontal axis and AD judgment value as the vertical axis to further reflect the uniformity of flux coating, such as Figure 10 shown.

[0085] The detection system of this embodiment provides a method for detecting the uniformity of flux spraying by detecting the trend of changes in electrical parameters after flux spraying through research on the physical properties of flux and analysis of its chemical molecular formula. The method is simultaneously implemented through software. After the test data is imported into the software, the software generates 3D graphics and automatically determines the uniformity of the spraying, replacing traditional manual visual judgment.

[0086] This embodiment also proposes a method for detecting the uniformity of solder flux using any of the above test boards. After the test board is subjected to a solder flux coating process in a wave soldering device, the method includes step S1, such as Figure 11 As shown, where:

[0087] S1, obtain the AD value of the electrode distribution point, and judge the uniformity of the flux on the test board based on the AD value.

[0088] After the test board of this embodiment is coated with flux, the distribution uniformity of the flux is determined by detecting the electrical parameters of each electrode distribution point after the flux is sprayed, that is, the change trend of the AD value. This embodiment analyzes the detection data in a digitized form to obtain a more accurate judgment result.

[0089] Further optionally, the test board of this embodiment is divided into multiple detection areas, and multiple electrode points are distributed in each detection area; step S1 includes S11 to S12, such as Figure 12 As shown, where:

[0090] S11, obtaining AD values ​​of a set number of electrode points in a preset number of detection areas on the test plate;

[0091] S12, judging the flux uniformity of each detection area according to the AD values ​​of a set number of electrode points in a preset number of detection areas; when the flux uniformity of the preset number of detection areas is qualified, judging that the flux uniformity on the test board is qualified; when the flux uniformity of any one of the preset number of detection areas is unqualified, judging that the flux uniformity on the test board is unqualified.

[0092] Because the spraying effect of the spray on different areas of the test board varies during the flux spraying process, for example, the spray on both sides of the test board is more affected during the test board's movement, while the spray in the middle is less affected. Therefore, it is optional to partition the test board into two sections and the middle section for flux uniformity judgment to obtain a more accurate judgment result. Only when the uniformity of all three test areas is qualified can the flux uniformity on the test board be judged to be qualified. If any one of the test areas fails the test, the flux uniformity of the entire test board is also unqualified. This embodiment ensures the accuracy of the uniformity judgment by partitioning the test board and performing partitioned testing and judgment on a preset number of test areas.

[0093] Further optionally, as Figure 13 As shown, step S12 includes S121 to S124, wherein:

[0094] S121, obtaining multiple AD values ​​for each electrode point, selecting the largest n values, and calculating the average of the largest n values ​​as the AD determination value for each electrode point;

[0095] S122, obtaining the maximum AD determination value and the minimum AD determination value of each detection zone in a preset number of detection zones, and calculating the average AD determination value of each detection zone;

[0096] S123 calculates a first deviation of the maximum AD determination value relative to the average AD determination value, and a second deviation of the minimum AD determination value relative to the average AD determination value;

[0097] S124, respectively compare the first deviation, the second deviation and the set deviation; when the first deviation and the second deviation are less than or equal to the set deviation, determine that the flux uniformity of the corresponding detection area is qualified; when the first deviation or the second deviation is greater than the set deviation, determine whether the flux uniformity of the corresponding detection area is qualified based on the difference between the maximum AD judgment value and the minimum AD judgment value; first deviation = (maximum AD judgment value - average AD judgment value) / average AD judgment value, second deviation = (average AD judgment value - minimum AD judgment value) / average AD judgment value.

[0098] This embodiment performs multiple sampling on the same electrode layout to ensure the accuracy of the sampling results. Because flux gradually evaporates, the largest n data points at each sampling point best represent the flux coating amount. n can be selected from 3 to 5, and the average of these n data points is used as the judgment value in the subsequent data analysis process. When determining the flux uniformity of each detection zone, the average AD judgment value of each detection zone is used as a reference standard. When the deviations of the maximum and minimum AD judgment values ​​of each of the preset number of detection zones relative to the average AD judgment value are both within a set deviation, such as 1%, the deviations of the AD judgment values ​​of all electrode layouts in the detection zone relative to the average AD judgment value of the detection zone are within the set deviation range, and the flux uniformity of the detection zone is qualified. If either the deviation of the maximum AD judgment value or the deviation of the minimum AD judgment value of each of the preset number of detection zones relative to the average AD judgment value is outside the set deviation, it is likely that the AD judgment values ​​of other electrode layouts are outside the set deviation value, and further judgment methods are required to determine whether the uniformity of the current detection zone is qualified. The uniformity determination of other detection zones is similar.

[0099] Further optionally, when the first deviation or the second deviation is greater than the set deviation, step S124 includes S1241 to S1242, such as Figure 14 As shown, where:

[0100] S1241, calculating the difference between the maximum AD determination value and the minimum AD determination value, and the maximum allowable difference;

[0101] S1242: Compare the difference between the maximum AD determination value and the minimum AD determination value with the maximum allowable difference; when the difference between the maximum AD determination value and the minimum AD determination value is less than or equal to the maximum allowable difference, determine that the flux uniformity of the corresponding inspection area is qualified; otherwise, determine that the flux uniformity of the corresponding inspection area is unqualified;

[0102] When one of the deviations of the maximum AD judgment value relative to the average AD judgment value and the deviation of the minimum AD judgment value relative to the average AD judgment value of each preset number of detection areas is outside the set deviation, it is further judged whether the difference between the maximum AD judgment value and the minimum AD judgment value is within the allowable difference. The allowable difference is a set multiple of the average AD judgment value, and the set multiple is less than 1. Optionally, the value range of the set multiple is 0.02 to 0.06, preferably 0.05.

[0103] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0104] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0105] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above technical content without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A detection system for detecting uniformity of soldering flux, characterized in that: The detection system comprises: A test board, wherein a plurality of electrode points are provided on the bottom of the test board, wherein the plurality of electrode points are arranged in a plurality of rows and columns in an array on the bottom of the board, and among the plurality of electrode points in the same row, the spacing between the plurality of electrode points on both sides of the bottom of the board is smaller than the spacing between the plurality of electrode points in the middle of the bottom of the board; A data detection module is electrically connected to the test board, and the data detection module detects the AD values ​​of all the electrode points after the electrode points are coated with flux; The data analysis module determines the uniformity of the soldering flux on the test board according to the AD value detected by the data detection module.

2. The detection system according to claim 1, characterized in that The intervals between the plurality of electrode points in the same column are equal.

3. The detection system according to claim 1 or 2, characterized in that: Each of the electrode points includes two positive and negative electrodes, and the interval between the two electrodes is 0.4 to 0.6 mm.

4. The detection system according to claim 1, characterized in that The test plate is divided into a plurality of detection areas, and a plurality of electrode points are distributed in each detection area; The data detection module detects the AD values ​​of a set number of electrode points in a preset number of detection areas respectively; The data analysis module judges the flux uniformity of each detection area based on a set number of AD values ​​in a preset number of detection areas; when the flux uniformity of all the preset number of detection areas is judged to be qualified, the flux uniformity of the test board is judged to be qualified; when the flux uniformity of any one of the preset number of detection areas is judged to be unqualified, the flux uniformity of the test board is judged to be unqualified.

5. The detection system according to claim 1, characterized in that The detection system also includes a data processing module, The data detection module detects the AD value of each electrode point at set intervals; The data processing module obtains multiple AD values ​​of each electrode point, selects the largest n values, and calculates the average value of the largest n values ​​as the AD determination value of each electrode point; The data analysis module obtains the maximum AD determination value and the minimum AD determination value of each detection area in a preset number of detection areas, and calculates the average AD determination value of each detection area; calculates a first deviation of the maximum AD determination value relative to the average AD determination value, and a second deviation of the minimum AD determination value relative to the average AD determination value; compares the first deviation, the second deviation and the set deviation respectively, and when the first deviation and the second deviation are less than or equal to the set deviation, determines that the flux uniformity of the corresponding detection area is qualified; when the first deviation or the second deviation is greater than the set deviation, determines whether the flux uniformity of the corresponding detection area is qualified according to the difference between the maximum AD determination value and the minimum AD determination value; The first deviation=(maximum AD determination value-average AD determination value) / average AD determination value, and the second deviation=(average AD determination value-minimum AD determination value) / average AD determination value.

6. The detection system according to claim 5, characterized in that: When it is determined that the first deviation or the second deviation is greater than the set deviation, the data analysis module further calculates the difference between the maximum AD determination value and the minimum AD determination value, and a maximum allowable difference, and compares the difference between the maximum AD determination value and the minimum AD determination value with the maximum allowable difference; When the difference between the maximum AD determination value and the minimum AD determination value is less than or equal to the maximum allowable difference, the flux uniformity of the corresponding detection area is determined to be qualified; otherwise, the flux uniformity of the corresponding detection area is determined to be unqualified; The maximum allowable difference is a set multiple of the average AD determination value, and the set multiple is less than 1.

7. The detection system according to claim 1, characterized in that Also includes A display module displays a three-dimensional graph of the AD values ​​of all electrode distribution points and / or a curve showing the AD values ​​of all electrode distribution points changing with time.

8. The detection system for detecting uniformity of soldering flux according to claim 1, characterized in that: The detection system further comprises a protection box, wherein the data detection module is located in the protection box, and the protection box is a high temperature resistant and heat insulating protection box.

9. A method for detecting uniformity of soldering flux using the detection system according to any one of claims 1 to 8, characterized in that: After the test board is subjected to flux coating in a wave soldering device, the method comprises: The AD values ​​of the electrode distribution points are obtained, and the uniformity of the soldering flux on the test board is judged according to the AD values.

10. The method according to claim 9, characterized in that The test board is divided into a plurality of test areas, each of which is distributed with a plurality of electrode distribution points; and the AD values ​​of the electrode distribution points are obtained, and the uniformity of the soldering flux on the test board is determined according to the AD values, including: Obtaining AD values ​​of a set number of electrode points within a preset number of detection areas on the test plate; The uniformity of the flux in each detection area is determined based on the AD values ​​of a set number of electrode points in a preset number of detection areas; When the flux uniformity of all the preset number of detection areas is qualified, the flux uniformity on the test board is determined to be qualified; when the flux uniformity of any one of the preset number of detection areas is unqualified, the flux uniformity on the test board is determined to be unqualified.

Images