Diode pin and circuit board welding quality detection system

Abstract

The invention relates to the technical field of test and inspection, in particular to a diode pin and circuit board welding quality detection system which comprises a transmission clamping module, a picture acquisition module, a position analysis module, a welding spot analysis module, a firmness detection analysis module, a comprehensive analysis module and a welding quality analysis database. According to the method, the welding position conformity, the welding quality conformity and the welding firmness conformity of the diode pins are comprehensively analyzed to obtain the comprehensive evaluation coefficient of diode welding, then the welding quality of the diode pins is quantitatively evaluated, and meanwhile the comprehensive welding quality of the diode pins can be comprehensively and accurately reflected; a basis is provided for determining whether diode pin welding is qualified; according to the invention, a mode of carrying out picture analysis and firmness test on the welding quality of the diode pin for synchronous detection is adopted, so that the efficiency of analyzing the welding quality of the diode pin is improved.

Description

Technical Field

[0001] The invention relates to the technical field of testing and inspection, and in particular to a diode pin and circuit board welding quality detection system. Background Art

[0002] Diodes are mainly used in various electronic circuits. By making reasonable connections between diodes and components such as resistors, capacitors, and inductors, circuits with different functions can be formed, which can realize multiple functions such as rectification of AC power, detection of modulated signals, limiting and clamping, and stabilization of power supply voltage. Diodes are mostly connected to circuit boards through welding methods set on them, thereby realizing electrical connection between the diodes and the circuit boards. Due to the important role of diodes on circuit boards and the fact that the circuit boards welded with diodes may be used in more complex environments, the diodes need to be tested for welding quality after welding.

[0003] The inspection of the welding between the diode pin and the circuit board is generally carried out by taking a picture of the diode pin, and then analyzing the picture to obtain the position and color of the diode pin welding point to judge the welding quality of the diode pin. At the same time, according to the requirements of the diode working environment, the diode on the circuit board will be tested for firmness through a pull-out tester.

[0004] Although the above-mentioned detection of the diode welding quality can detect the defects of the diode pin welding to a certain extent, it is impossible to quantify and evaluate the welding quality of the diode with higher quality requirements, so that although the diode with poor welding quality will not affect its performance temporarily, with the long-term use of the circuit board, the diode with poor welding quality will be damaged or the working performance will be reduced; at the same time, the data of the pin monitoring on the diode is relatively single, and it is impossible to comprehensively and objectively analyze the welding quality of the diode pin; because there may be welding defects at the welding points on the diode pins, the above-mentioned analysis method cannot determine whether the welding defects at the welding points on the diode pins are within an appropriate range, which causes uncertainty in the judgment of the diode pin welding; in addition, the welding quality detection and firmness detection of the diode pins need to be tested separately, resulting in low efficiency of the diode pin welding quality detection. Summary of the invention

[0005] The present invention solves the above technical problems. The present invention adopts the following technical solutions: A diode pin and circuit board welding quality inspection system comprises: a conveying and clamping module, which is used to convey the circuit board after welding according to a preset path, and make the circuit board pass through the image acquisition module and the firmness detection module in sequence, and the conveying and clamping module is also used to control the circuit board to be transmitted to the position of the image acquisition module and the firmness detection module to locate and clamp the circuit board.

[0006] The image acquisition module is used to take high-definition images of the circuit board at preset angles after the circuit board is transmitted to the position of the image acquisition module, and then obtain high-definition pictures of the diode at preset angles. The high-definition pictures of the diode at preset angles are divided into high-definition pictures of the position relationship of the diode and high-definition pictures of the position of each solder point of the diode.

[0007] The position analysis module is used to read the high-definition pictures of the position relationship of the diode and obtain the defect information of each pin of the diode through picture processing and analysis. The diode welding position compliance is obtained through the defect information analysis of each pin of the diode, which is recorded as .

[0008] The solder joint analysis module is used to read the high-definition pictures of the positions of the solder joints of the diodes and obtain the shape deviation and quality deviation of the diode welding through picture processing and analysis. The shape deviation and quality deviation of the diode welding are analyzed to obtain the diode welding quality compliance, which is recorded as .

[0009] The firmness detection and analysis module is used to test the stability of the diode pins of the circuit board that has been delivered to the position. The stability of the diode pins is tested by the pull-out tester and vibration tester on the firmness detection and analysis module, and the displacement of each diode pin is recorded. The analysis end on the firmness detection and analysis module obtains the firmness compliance of the diode welding by analyzing the displacement of each diode pin.

[0010] The comprehensive analysis module obtains the comprehensive evaluation coefficient of diode welding by analyzing the firmness compliance of diode welding, the quality compliance of diode welding and the compliance of diode welding position, and judges the welding quality of diode pins by the comprehensive evaluation coefficient.

[0011] The welding quality analysis database is used to store the welding positions of diodes on various circuit boards and various standard parameters for the welding of diode pins.

[0012] Furthermore, the specific working method of the image acquisition module is as follows: in the first step, after the circuit board is moved to the position of the image acquisition module, the circuit board at the current position is positioned and clamped by the conveying and clamping module.

[0013] The second step is to control the image acquisition module to acquire images of the marking points on the circuit board. The image acquisition module can fine-tune the photographing position of the diode by the marking points on the circuit board.

[0014] The third step is to take high-definition images of the diode at preset angles by reading the welding position of the diode on the circuit board, thereby obtaining high-definition pictures of the diode at each preset angle, and dividing the high-definition pictures of the diode at each preset angle into high-definition pictures of the position relationship of the diode and high-definition pictures of the position of each solder point of the diode according to a predefined method for each angle.

[0015] In the fourth step, after the current circuit board is photographed, the conveying and clamping module ends the clamping of the circuit board and controls the current circuit board to be moved out of the position of the image acquisition module, and at the same time controls the circuit board to be photographed to move to the position of the image acquisition module for photographing.

[0016] Furthermore, the defect information of each pin of the diode includes: the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode; the specific working method of the position analysis module is: by reading the high-definition pictures of the position relationship of each diode and processing the high-definition pictures, the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode are obtained, and the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad are recorded as , and select the largest horizontal distance and vertical distance and record them as , k represents the kth pin of the diode, , the defect or damage area of ​​each pin of the diode is recorded as , Indicates the diode A defective or damaged pin. ,and , through the formula Get the deviation of the diode pin position , m represents the number of diode pins, Indicates the standard lateral distance between the diode pin and the corresponding pad. Indicates the standard longitudinal distance between the diode pin and the corresponding pad. They respectively represent the influence weight of the horizontal distance and the vertical distance between the diode pin and the corresponding pad. The conformity of the diode welding position is analyzed by considering the defect or damage area of ​​each diode pin and the deviation of the diode pin position.

[0017] Furthermore, the calculation formula for the diode welding position compliance is: , e represents a natural constant, Indicates the number of pins on the diode that are defective or damaged. Indicates the area within which the diode pins are allowed to be defective or damaged.

[0018] Furthermore, the specific analysis method of the shape deviation of the diode welding is: by reading the high-definition pictures of the positions of the diode solder joints, and obtaining the solder wrapping amount and wrapping height on the upper part of each pin of the diode, the climbing height of the solder on each pin, and the brightness of the solder on each pin by image analysis, and recording them as , and by the formula YJ k = [ ( 1 + | V k - V standard | V standard ) * ( 1 + | H 1 k - H 1 standard | H 1 standard ) ] * V standard + 1 V k + 1 Calculate the solder wrap index of each diode pin , They represent the standard wrapping amount and standard wrapping height of the solder on the diode pins respectively. Substitute the solder wrapping index of each diode pin, the climbing height of the solder on each pin, and the brightness of the solder on each pin into the formula Then the shape deviation of the diode welding is obtained , Indicates the standard rise height of solder on diode pins. Indicates the recommended brightness of the solder on the diode pins.

[0019] Furthermore, the specific analysis method of the quality deviation of the diode welding is as follows: by reading high-definition pictures of the positions of the solder joints of the diode, and obtaining the types and corresponding quantities of abnormal points of the solder on each pin of the diode by image analysis, the types of abnormal points of the solder include solder protrusions, solder depressions, solder cracks, and solder bubbles, and the numbers of abnormal points of the solder on each pin of the diode, which are solder protrusions, solder depressions, solder cracks, and solder bubbles, are recorded as , through the formula Calculate the soldering defect index of each diode pin , They respectively represent the influence parameters of the preset solder abnormal point as solder protrusion, the influence parameters of the solder abnormal point as solder depression, the influence parameters of the solder abnormal point as solder crack, and the influence parameters of the solder abnormal point as solder bubble; by analyzing the high-definition pictures of the positions of the solder joints of the diode, the short-circuit parameters between the adjacent pins of the diode can be obtained, and recorded as If there is a tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 0. If there is no tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 1. The short-circuit parameters between the adjacent pins of the diode are multiplied to obtain the short-circuit parameter between the diode pins. , by substituting the soldering defect index of each diode pin and the short circuit parameter between the diode pins into the formula Get the quality deviation of diode welding , Indicates the preset diode pin welding quality deviation threshold, This is a correction factor that indicates the quality deviation of diode welding.

[0020] Furthermore, the analysis method of the diode welding quality compliance is as follows: Substitute the shape deviation of the diode welding and the quality deviation of the diode welding into the formula Calculate the diode welding quality compliance .

[0021] Furthermore, the specific working method of the firmness detection and analysis module is as follows: after the conveying and clamping module controls the circuit board to be conveyed to the position of the firmness detection and analysis module, the circuit board is positioned and clamped by the conveying and clamping module, and the marking points on the circuit board are identified by the positioning end on the firmness detection and analysis module. The firmness detection and analysis module can determine the positions of the pull-out tester and the vibration tester by identifying the circuit board with its positioning end, so that the pull-out tester and the vibration tester are directly opposite to the pins of the diode on the circuit board. The pull-out tester is used to perform pull-out tests of various test strengths on each pin of the diode, and the displacement of each pin of the diode during the pull-out tests of various test strengths is recorded as , p represents the pth pulling test strength, The vibration tester is used to perform vibration tests on circuit boards. The displacement of each pin of the diode is monitored during the vibration of the circuit board and recorded as The firmness of the diode welding is analyzed based on the displacement of each pin of the diode during the pull test with different test forces and the displacement of each pin of the diode during the vibration test.

[0022] Furthermore, the calculation formula for the firmness compliance of the diode welding is: , Indicates the allowable displacement of the diode pins when the circuit board is subjected to vibration testing. A correction factor indicating the degree of firmness of diode soldering.

[0023] Furthermore, the comprehensive evaluation coefficient of the diode welding is analyzed by substituting the diode welding firmness compliance, diode welding quality compliance, and diode welding position compliance into the formula , and then get the comprehensive evaluation coefficient of diode welding , They respectively represent the weight ratio of the firmness compliance of diode welding, the weight ratio of the quality compliance of diode welding, and the weight ratio of the diode welding position compliance. The comprehensive evaluation coefficient of diode welding is compared with the comprehensive evaluation coefficient threshold of diode welding. If the comprehensive evaluation coefficient of diode welding is greater than the comprehensive evaluation coefficient threshold of diode welding, it means that the diode welding meets the requirements, otherwise it does not meet the requirements.

[0024] The beneficial effects of the system are as follows: 1. The present invention obtains a comprehensive evaluation coefficient of diode welding by comprehensively analyzing the welding position compliance, welding quality compliance, and welding firmness compliance of the diode pin, and then quantitatively evaluates the quality of the diode pin welding. At the same time, it can comprehensively and accurately reflect the comprehensive welding quality of the diode pin, and provide a basis for whether the diode pin welding is qualified; the present invention adopts a method of synchronously detecting the welding quality of the diode pin by performing image analysis and firmness test, thereby increasing the efficiency of the diode pin welding quality analysis.

[0025] 2. The present invention obtains and analyzes the welding position of each pin of the diode by image analysis, and then determines whether the pin of the diode is in the specified welding position, so as to prevent the diode from being affected in its later performance and service life due to pin deviation or overall position deviation.

[0026] 3. When calculating the welding position compliance of the diode, the present invention not only refers to the lateral distance and longitudinal distance between each pin and the corresponding pad, but also needs to calculate the maximum lateral distance and maximum longitudinal distance between the pin and the corresponding pad. The above maximum lateral distance and maximum longitudinal distance may be caused by the deflection of the diode pin. Therefore, by referring to the maximum lateral distance and maximum longitudinal distance between the pin and the corresponding pad, the accuracy of the deviation of the diode pin position can be increased.

[0027] Fourth, the present invention reflects whether the solder is in a suitable shape through the shape deviation of each solder joint of the diode, and the quality deviation reflects whether there are various defects in the solder joint. Through the above analysis, the pin welding quality of the diode can be comprehensively analyzed.

[0028] 5. The pull-out tester on the firmness detection and analysis module of the present invention performs pull-out tests on the pins of the diode with different forces, and determines whether the pins of the diode are displaced in the above tests. The vibration tester performs vibration tests on the diodes on the circuit board, and analyzes the displacement of the diode to determine whether the overall welding quality of the diode meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention is further described using the accompanying drawings, but the embodiments in the accompanying drawings do not constitute any limitation to the present invention. A person skilled in the art can obtain other drawings based on the following drawings without creative work.

[0030] Figure 1 It is a schematic diagram of the connection between various modules of the present invention.

[0031] Figure 2 It is a specific workflow diagram of the picture acquisition module of the present invention.

[0032] Figure 3It is a schematic diagram for analyzing the conformity of the diode welding position of the present invention.

[0033] Figure 4 It is a schematic diagram of analyzing the diode welding quality compliance of the present invention. DETAILED DESCRIPTION

[0034] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in the art or the product specifications are used.

[0035] See also Figure 1 A diode pin and circuit board welding quality detection system includes: a transmission and clamping module, a picture acquisition module, a position analysis module, a solder point analysis module, a firmness detection analysis module, a comprehensive analysis module, and a welding quality analysis database, wherein the welding quality analysis database is respectively connected to the comprehensive analysis module, the position analysis module, the solder point analysis module, the firmness detection analysis module, the transmission and clamping module, and the picture acquisition module, the picture acquisition module is respectively connected to the position analysis module and the solder point analysis module, the comprehensive analysis module is respectively connected to the position analysis module, the solder point analysis module, and the firmness detection analysis module, and the transmission and clamping module is respectively connected to the picture acquisition module and the firmness detection analysis module.

[0036] The welding quality analysis database is used to store the welding positions of diodes on various circuit boards and various standard parameters for the welding of diode pins.

[0037] The conveying and clamping module is used to convey the circuit board after welding according to a preset path, and to make the circuit board pass through the image acquisition module and the firmness detection module in sequence, and the conveying and clamping module is also used to control the circuit board to be conveyed to the position of the image acquisition module and the firmness detection module to position and clamp the circuit board. The conveying and clamping module can complete the sequential conveying of the circuit board, so that the diodes of the circuit board are sequentially photographed and analyzed and the welding firmness is detected, and the position can be positioned and locked at the photographing or detection position of the circuit board through the conveying and clamping module, thereby preventing the position deviation of the diode on the circuit board from causing deviation in the analysis of the diode welding quality.

[0038] The image acquisition module is used to take high-definition images of the circuit board at preset angles after the circuit board is transferred to the position of the image acquisition module, and then obtain high-definition images of the diode at preset angles. The high-definition images of the diode at preset angles are divided into high-definition images of the position relationship of the diode and high-definition images of the positions of the solder joints of the diode. It should be noted that for different types of diodes, the image acquisition module has a slight deviation in the shooting angle of the diode. By processing the high-definition images at preset angles, the information of each pin of the diode can be obtained, which is convenient for later analysis.

[0039] See also Figure 2 ,The specific working mode of the picture acquisition module is as follows: ,In the first step, when the circuit board moves to the position of the ,picture acquisition module, the circuit board at the current position is positioned and ,clamped by the transmission and clamping module.

[0040] The second step is to control the image acquisition module to acquire images of the marking points on the circuit board. The image acquisition module can fine-tune the photographing position of the diode based on the marking points on the circuit board, thereby increasing the accuracy of diode image acquisition.

[0041] The third step is to take high-definition images of the diode at preset angles by reading the welding position of the diode on the circuit board, thereby obtaining high-definition pictures of the diode at each preset angle, and dividing the high-definition pictures of the diode at each preset angle into high-definition pictures of the position relationship of the diode and high-definition pictures of the position of each solder point of the diode according to a predefined method for each angle.

[0042] In the fourth step, after the current circuit board is photographed, the conveying and clamping module ends the clamping of the circuit board and controls the current circuit board to be moved out of the position of the image acquisition module, and at the same time controls the circuit board to be photographed to be moved to the position of the image acquisition module for photographing. The present invention adopts a continuous analysis method to analyze the circuit board in sequence, and the circuit board is in a position-locked state when the diode on the circuit board is photographed, thereby increasing the accuracy of diode image acquisition. In addition, the image acquisition module can also calibrate the position of the circuit board through the marking points on the circuit board, further increasing the accuracy of diode image shooting on the circuit board.

[0043] The position analysis module is used to read the high-definition pictures of the position relationship of the diode and obtain the defect information of each pin of the diode through picture processing and analysis. The defect information of each pin of the diode includes: the horizontal distance and vertical distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode; and the diode welding position compliance is obtained through the defect information analysis of each pin of the diode, which is recorded as The present invention acquires and analyzes the welding position of each pin of the diode by means of image analysis, and then determines whether the pin of the diode is in the specified welding position, so as to prevent the diode from affecting its later performance and service life due to pin deflection or overall position deflection; the lateral distance and longitudinal distance between each pin of the diode and the corresponding pad can reflect the lateral and longitudinal deflection of the diode pin, and the defective or damaged area of ​​each pin of the diode has the hidden danger of affecting the normal operation of the diode.

[0044] It can be understood that, since the pads arranged on the surface of the circuit board are slightly larger than the pins of the electronic parts when the circuit board is designed, a better welding position for the electronic parts is when the pins of the electronic parts are located at the center of the corresponding pads. The present invention adopts a unilateral calculation method for the lateral distance and longitudinal distance between the diode pins and the corresponding pads, that is, the distance between the pins and the upper side of the pads is calculated through the top view of the diode on the circuit board, and is recorded as the longitudinal distance between the diode pins and the corresponding pads, and the distance between the diode pins and the side of one end of the pads is recorded as the lateral distance between the diode pins and the corresponding pads.

[0045] See also Figure 3 The specific working method of the position analysis module is as follows: by reading the high-definition pictures of the position relationship of the diode and processing the high-definition pictures, the horizontal distance and vertical distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode are obtained, and the horizontal distance and vertical distance between each pin of the diode and the corresponding pad are recorded as , and select the largest horizontal distance and vertical distance and record them as , k represents the kth pin of the diode, , the defect or damage area of ​​each pin of the diode is recorded as , Indicates the diode A defective or damaged pin. ,and , through the formula Get the deviation of the diode pin position , m represents the number of diode pins, Indicates the standard lateral distance between the diode pin and the corresponding pad. Indicates the standard longitudinal distance between the diode pin and the corresponding pad. They represent the influence weight of the horizontal distance and the vertical distance between the diode pin and the corresponding pad, respectively, and , exemplary, The values ​​of are 0.4 and 0.6 respectively; the defect or damage area of ​​each diode pin and the deviation of the diode pin position are substituted into the formula The conformity of the diode welding position is obtained, e represents the natural constant, Indicates the number of pins on the diode that are defective or damaged. Indicates the area where the diode pin is allowed to be defective or damaged. When calculating the welding position compliance of the diode, the present invention not only refers to the lateral distance and longitudinal distance between each pin and the corresponding pad, but also needs to calculate the maximum lateral distance and maximum longitudinal distance between the pin and the corresponding pad. The above maximum lateral distance and maximum longitudinal distance may be caused by the deflection of the diode pin. Therefore, by referring to the maximum lateral distance and maximum longitudinal distance between the pin and the corresponding pad, the accuracy of the deviation of the diode pin position can be increased; in addition, when analyzing the welding position compliance of the diode, if the defective or damaged area of ​​any pin of the diode is greater than the area where the diode pin is allowed to be defective or damaged, the welding position compliance of the diode is directly judged to be zero.

[0046] See also Figure 4 The solder joint analysis module is used to read the high-definition images of the positions of the solder joints of the diode and obtain the shape deviation and quality deviation of the diode welding through image processing and analysis. The shape deviation and quality deviation of the diode welding are analyzed to obtain the diode welding quality compliance, which is recorded as The present invention reflects whether the solder is in a suitable shape through the shape deviation of each solder joint of the diode, and the quality deviation reflects whether there are various defects in the solder joint. Through the above analysis, the pin welding quality of the diode can be comprehensively analyzed.

[0047] The specific analysis method of the shape deviation of diode welding is as follows: by reading the high-definition pictures of the positions of the diode solder joints, and by image analysis, the solder wrapping amount and wrapping height on the upper part of each diode pin, the solder climbing height on each pin, and the brightness of each solder pin are obtained, and they are recorded as , and by the formula YJ k = [ ( 1 + | V k - V standard | V standard ) * ( 1 + | H 1 k - H 1 standard | H 1 standard ) ] * V standard + 1 V k + 1 Calculate the solder wrap index of each diode pin , They represent the standard wrapping amount and standard wrapping height of the solder on the diode pins respectively. Substitute the solder wrapping index of each diode pin, the climbing height of the solder on each pin, and the brightness of the solder on each pin into the formula Then the shape deviation of the diode welding is obtained , Indicates the standard rise height of solder on diode pins. Indicates the recommended brightness of the solder on the diode pin. The shape deviation of the diode welding is determined by the amount of solder wrapped on the top of each diode pin and the height of the wrapping. Too much or too little solder will affect the welding quality of the diode pin; the climbing height of the solder on each pin can reflect whether the solder is full or excessive. Too high or too low climbing height of the solder on each pin will have a negative impact on the welding quality of the pin; the brightness of the solder on each pin is used to reflect the welding effect of the diode pin. The brighter the brightness of the solder on the pin, the better the welding effect of the pin.

[0048] The specific analysis method of the quality deviation of diode welding is as follows: by reading high-definition pictures of the positions of each solder joint of the diode, and obtaining the types and corresponding quantities of abnormal points of solder on each pin of the diode by image analysis, the types of abnormal points of solder include solder protrusions, solder depressions, solder cracks, and solder bubbles. The number of abnormal points of solder protrusions, solder depressions, solder cracks, and solder bubbles on each pin of the diode is recorded as , through the formula Calculate the soldering defect index of each diode pin , They respectively represent the influence parameters of the preset abnormal solder point being solder protrusion, the influence parameters of the abnormal solder point being solder depression, the influence parameters of the abnormal solder point being solder crack, and the influence parameters of the abnormal solder point being solder bubble. It is the industry standard setting value manually input at the initial use; by analyzing the high-definition pictures of the positions of the diode solder joints, the short-circuit parameters between the adjacent pins of the diode can be obtained and recorded as If there is a tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 0. If there is no tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 1. The short-circuit parameters between the adjacent pins of the diode are multiplied to obtain the short-circuit parameter between the diode pins. , by substituting the soldering defect index of each diode pin and the short circuit parameter between the diode pins into the formula Get the quality deviation of diode welding , Indicates the preset diode pin welding quality deviation threshold, The correction factor for the quality deviation of diode welding is It is the industry standard setting value manually input during initial use; the calculation formula for diode welding quality compliance is: The quality deviation of diode welding is used to reflect whether there are quality problems in each pin of the diode, and the common quality defects of diode pin welding are classified, and different defect types are assigned corresponding defect impact parameters, and then the defect conditions of each pin of the diode are quantified to obtain the defect index of each pin of the diode. If the defect index of any pin of the diode is greater than or equal to the welding quality deviation threshold of the diode pin or there is a short circuit between adjacent pins of the diode, the quality deviation of the diode welding is zero.

[0049] The firmness detection and analysis module is used to test the stability of the diode pins of the circuit board that has been delivered to the position. The stability of the diode pins is tested by the pull-out tester and vibration tester on the firmness detection and analysis module, and the displacement of each diode pin is recorded. The analysis end on the firmness detection and analysis module obtains the firmness compliance of the diode welding by analyzing the displacement of each diode pin.

[0050] The specific working method of the firmness detection and analysis module is as follows: after the conveying and clamping module controls the circuit board to be conveyed to the position of the firmness detection and analysis module, the conveying and clamping module is used to position and clamp the circuit board, and the positioning end on the firmness detection and analysis module is used to identify the marking points on the circuit board. The firmness detection and analysis module can determine the positions of the pull-out tester and the vibration tester by identifying the circuit board with its positioning end, so that the pull-out tester and the vibration tester are directly facing the pins of the diode on the circuit board. The pull-out tester is used to perform pull-out tests of various test forces on each pin of the diode, and the displacement of each pin of the diode during the pull-out test of various test forces is recorded as , p represents the pth pulling test strength, The vibration tester is used to perform vibration tests on circuit boards. The displacement of each pin of the diode is monitored during the vibration of the circuit board and recorded as The firmness of the diode welding is analyzed based on the displacement of each pin of the diode during the pull test with different test forces and the displacement of each pin of the diode during the vibration test.

[0051] The calculation formula for the firmness of diode welding is: , Indicates the allowable displacement of the diode pins when the circuit board is subjected to vibration testing. The correction factor indicating the firmness of the diode welding is It is the industry standard setting value manually input at the time of initial use. Since some problems of cold solder joints or loose soldering of the diode pins cannot be detected through pictures, it is necessary to analyze the diode pins by using a detector. The pull-out tester on the firmness detection and analysis module of the present invention performs pull-out tests on the diode pins with different strengths, and determines whether the diode pins are displaced in the above tests. The vibration tester performs vibration tests on the diodes on the circuit board, and analyzes the displacement of the diodes to determine whether the overall welding quality of the diodes meets the requirements.

[0052] It can be understood that when the diode pins are subjected to pull-out tests with different strengths by a pull-out tester, the diode pins should not be displaced, while when the diode pins are subjected to vibration tests, displacement within a specified range is allowed; at the same time, the pull-out tester performs non-destructive testing on the diode pins, that is, the maximum pull-out force of the pull-out tester should be less than the maximum force that the diode pins can withstand.

[0053] The comprehensive analysis module obtains the comprehensive evaluation coefficient of diode welding by analyzing the firmness compliance of diode welding, the quality compliance of diode welding, and the compliance of diode welding position, and judges the welding quality of diode pins by the comprehensive evaluation coefficient. The analysis method of the comprehensive evaluation coefficient of diode welding is: Substitute the firmness compliance of diode welding, the quality compliance of diode welding, and the compliance of diode welding position into the formula , and then get the comprehensive evaluation coefficient of diode welding , Respectively represent the weight ratio of the diode welding firmness compliance, the weight ratio of the diode welding quality compliance, and the weight ratio of the diode welding position compliance. For example, The values ​​are 0.35, 0.45, and 0.2 respectively. The comprehensive evaluation coefficient of diode welding is compared with the comprehensive evaluation coefficient threshold of diode welding. If the comprehensive evaluation coefficient of diode welding is greater than the comprehensive evaluation coefficient threshold of diode welding, it means that the diode welding meets the requirements, otherwise it does not meet the requirements. The present invention obtains the comprehensive evaluation coefficient of diode welding by comprehensively analyzing the welding position compliance, welding quality compliance, and welding firmness compliance of the diode pin, which can comprehensively and accurately reflect the comprehensive welding quality of the diode pin and provide a basis for whether the diode pin welding is qualified.

[0054] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention and they are still covered by the protection scope of the present invention.

Claims

1. A diode pin and circuit board welding quality detection system, characterized in that: The quality inspection system includes: The conveying and clamping module is used to convey the soldered circuit board according to a preset path, and to make the circuit board pass through the image acquisition module and the firmness detection module in sequence, and the conveying and clamping module is also used to control the position of the circuit board when it is conveyed to the position of the image acquisition module and the firmness detection module to locate and clamp the circuit board; The image acquisition module is used to take high-definition images of the circuit board at preset angles after the circuit board is transferred to the position of the image acquisition module, and then obtain high-definition images of the diode at preset angles. The high-definition images of the diode at preset angles are divided into high-definition images of the relationship between the positions of the diode and high-definition images of the positions of the solder joints of the diode; The position analysis module is used to read the high-definition pictures of the position relationship of the diode and obtain the defect information of each pin of the diode through picture processing and analysis. The diode welding position compliance is obtained through the defect information analysis of each pin of the diode, which is recorded as ; The solder joint analysis module is used to read the high-definition pictures of the positions of the solder joints of the diodes and obtain the shape deviation and quality deviation of the diode welding through picture processing and analysis. The shape deviation and quality deviation of the diode welding are analyzed to obtain the quality compliance of the diode welding, which is recorded as ; The firmness detection and analysis module is used to test the stability of the diode pins of the delivered circuit board. The pull-out tester and vibration tester on the firmness detection and analysis module are used to test the stability of the diode pins and record the displacement of each diode pin. The analysis end on the firmness detection and analysis module obtains the firmness compliance of the diode welding through the displacement of each diode pin. The comprehensive analysis module obtains the comprehensive evaluation coefficient of diode welding by analyzing the firmness compliance of diode welding, the quality compliance of diode welding and the compliance of diode welding position, and judges the welding quality of diode pins by the comprehensive evaluation coefficient; The welding quality analysis database is used to store the welding positions of diodes on various circuit boards and various standard parameters for the welding of diode pins.

2. According to claim 1, a diode pin and circuit board welding quality detection system is characterized in that: The specific working method of the image acquisition module is as follows: in the first step, after the circuit board is moved to the position of the image acquisition module, the circuit board at the current position is positioned and clamped by the conveying and clamping module; The second step is to control the image acquisition module to acquire images of the marking points on the circuit board, and the image acquisition module can fine-tune the photographing position of the diode by the marking points on the circuit board; The third step is to take high-definition images of the diode at various preset angles by reading the welding position of the diode on the circuit board, thereby obtaining high-definition pictures of the diode at various preset angles, and dividing the high-definition pictures of the diode at various preset angles into high-definition pictures of the relationship between the positions of the diode and high-definition pictures of the positions of the welding points of the diode according to the predefined method for each angle; In the fourth step, after the current circuit board is photographed, the conveying and clamping module ends the clamping of the circuit board and controls the current circuit board to be moved out of the position of the image acquisition module, and at the same time controls the circuit board to be photographed to move to the position of the image acquisition module for photographing.

3. According to claim 1, a diode pin and circuit board welding quality detection system is characterized in that: The defect information of each pin of the diode includes: the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode; the specific working method of the position analysis module is: by reading the high-definition pictures of the position relationship of each diode and processing the high-definition pictures, the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad, and the defect or damage area of ​​each pin of the diode are obtained, and the lateral distance and the longitudinal distance between each pin of the diode and the corresponding pad are recorded as , and select the largest horizontal distance and vertical distance and record them as , k represents the kth pin of the diode, , the defect or damage area of ​​each pin of the diode is recorded as , Indicates the diode A defective or damaged pin. ,and , through the formula Get the deviation of the diode pin position , m represents the number of diode pins, Indicates the standard lateral distance between the diode pin and the corresponding pad. Indicates the standard longitudinal distance between the diode pin and the corresponding pad. They respectively represent the influence weight of the horizontal distance and the vertical distance between the diode pin and the corresponding pad. The conformity of the diode welding position is analyzed by considering the defect or damage area of ​​each diode pin and the deviation of the diode pin position.

4. A diode pin and circuit board welding quality detection system according to claim 3, characterized in that: The calculation formula for the diode welding position compliance is: , e represents a natural constant, Indicates the number of pins on the diode that are defective or damaged. Indicates the area within which the diode pins are allowed to be defective or damaged.

5. A diode pin and circuit board welding quality detection system according to claim 1, characterized in that: The specific analysis method of the shape deviation of the diode welding is: by reading the high-definition pictures of the positions of the diode solder joints, and obtaining the solder wrapping amount and wrapping height on the upper part of each pin of the diode, the climbing height of the solder on each pin, and the brightness of the solder on each pin by image analysis, and recording them as , and by the formula Calculate the solder wrap index of each diode pin , They represent the standard wrapping amount and standard wrapping height of the solder on the diode pins respectively. Substitute the solder wrapping index of each diode pin, the climbing height of the solder on each pin, and the brightness of the solder on each pin into the formula Then the shape deviation of the diode welding is obtained , Indicates the standard rise height of solder on diode pins. Indicates the recommended brightness of the solder on the diode pins.

6. A diode pin and circuit board welding quality detection system according to claim 5, characterized in that: The specific analysis method of the quality deviation of the diode welding is as follows: by reading the high-definition pictures of the positions of the solder joints of the diode, and obtaining the types and corresponding quantities of the abnormal points of the solder on each pin of the diode by image analysis, the types of abnormal points of the solder include solder protrusions, solder depressions, solder cracks, and solder bubbles, and the quantities of the abnormal points of the solder protrusions, solder depressions, solder cracks, and solder bubbles on each pin of the diode are recorded as , through the formula Calculate the soldering defect index of each diode pin , They respectively represent the influence parameters of the preset solder abnormal point as solder protrusion, the influence parameters of the solder abnormal point as solder depression, the influence parameters of the solder abnormal point as solder crack, and the influence parameters of the solder abnormal point as solder bubble; by analyzing the high-definition pictures of the positions of the solder joints of the diode, the short-circuit parameters between the adjacent pins of the diode can be obtained, and recorded as If there is a tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 0. If there is no tin bridge between adjacent pins of the diode, the value of the short-circuit parameter between the adjacent pins of the diode is 1. The short-circuit parameters between the adjacent pins of the diode are multiplied to obtain the short-circuit parameter between the diode pins. , by substituting the soldering defect index of each diode pin and the short circuit parameter between the diode pins into the formula Get the quality deviation of diode welding , Indicates the preset diode pin welding quality deviation threshold, This is a correction factor that indicates the quality deviation of diode welding.

7. A diode pin and circuit board welding quality detection system according to claim 6, characterized in that: The analysis method of the diode welding quality compliance is as follows: Substitute the shape deviation of the diode welding and the quality deviation of the diode welding into the formula Calculate the diode welding quality compliance .

8. A diode pin and circuit board welding quality detection system according to claim 1, characterized in that: The specific working method of the firmness detection and analysis module is as follows: after the conveying and clamping module controls the circuit board to be conveyed to the position of the firmness detection and analysis module, the conveying and clamping module is used to position and clamp the circuit board, and the positioning end on the firmness detection and analysis module is used to identify the marking point on the circuit board. The firmness detection and analysis module can determine the position of the pull-out tester and the vibration tester by identifying the circuit board with its positioning end, so that the pull-out tester and the vibration tester are directly facing the pins of the diode on the circuit board. The pull-out tester is used to perform pull-out tests of various test forces on each pin of the diode, and the displacement of each pin of the diode during the pull-out test of various test forces is recorded as , p represents the pth pulling test strength, The vibration tester is used to perform vibration tests on circuit boards. The displacement of each pin of the diode is monitored during the vibration of the circuit board and recorded as The firmness of the diode welding is analyzed based on the displacement of each pin of the diode during the pull test with different test forces and the displacement of each pin of the diode during the vibration test.

9. A diode pin and circuit board welding quality detection system according to claim 8, characterized in that: The calculation formula for the firmness of the diode welding is: , Indicates the allowable displacement of the diode pins when the circuit board is subjected to vibration testing. A correction factor indicating the degree of firmness of diode soldering.

10. A diode pin and circuit board welding quality detection system according to claim 9, characterized in that: The comprehensive evaluation coefficient of the diode welding is analyzed by substituting the diode welding firmness compliance, diode welding quality compliance, and diode welding position compliance into the formula: , and then get the comprehensive evaluation coefficient of diode welding , They respectively represent the weight ratio of the firmness compliance of diode welding, the weight ratio of the quality compliance of diode welding, and the weight ratio of the diode welding position compliance. The comprehensive evaluation coefficient of diode welding is compared with the comprehensive evaluation coefficient threshold of diode welding. If the comprehensive evaluation coefficient of diode welding is greater than the comprehensive evaluation coefficient threshold of diode welding, it means that the diode welding meets the requirements, otherwise it does not meet the requirements.

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