System and method for monitoring and controlling process of PCB chemical nickel gold production line

Abstract

The invention relates to the technical field of production line monitoring, in particular to a PCB chemical nickel gold production line process monitoring control system and method, and the system comprises a production line monitoring control center, a front-end processing unit, a coating analysis unit, a uniformity analysis unit, a defect interference unit and an early warning end. According to the method, analysis is performed preliminarily from the perspective of front-end pretreatment of the PCB chemical nickel-gold production line so as to reduce interference of the front-end pretreatment on the quality of the plating layer on the surface of the PCB in the later stage, and the quality of the plating layer on the surface of the PCB is analyzed based on the stability of the front-end pretreatment so that whether the PCB after plating layer processing is qualified or not can be visually known; according to the method, the PCB chemical nickel-gold production line is used for guaranteeing the production efficiency of the PCB chemical nickel-gold production line, deep analysis is carried out from two perspectives of processing qualification and processing disqualification, on one hand, the quality condition of the PCB surface plating layer is further determined, and on the other hand, whether the PCB plating layer disqualification is caused by the fact that operation and plating solution parameters do not meet requirements or not is judged. The interference of operation and plating solution parameters on the quality of a PCB plating layer is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of production line monitoring, and particularly to a process monitoring and control system and method for a PCB chemical nickel-gold production line. Background Art

[0002] Chemical nickel-gold, also known as electroless nickel immersion gold, immersion nickel gold, or electroless nickel gold, is a process in which a layer of nickel-phosphorus alloy is chemically plated on the surface of copper by a chemical reaction to displace palladium, and then a layer of gold is plated on the surface of nickel through a displacement reaction. There are two processes for the immersion gold of chemical nickel-gold: displacement and a mixed bath of semi-displacement and semi-reduction.

[0003] Chemical nickel-gold is mainly used for the surface treatment of circuit boards to prevent the copper on the surface of the circuit board from being oxidized or corroded. When monitoring and controlling the process of the current PCB chemical nickel-gold production line, it is impossible to safely supervise the front-end pretreatment of the PCB on the production line, resulting in poor front-end pretreatment effect of the PCB, which in turn reduces the plating quality of the PCB surface in the later stage. At the same time, it is impossible to analyze the plating quality of the PCB surface, which is not conducive to the reasonable and targeted management of the production line, reduces the processing quality of the production line, and is unable to eliminate the reasons for the poor plating quality of the PCB surface, resulting in untimely management of the production line and reducing the management efficiency of the production line.

[0004] In view of the above technical deficiencies, a solution is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a process monitoring and control system and method for a PCB chemical nickel-gold production line to solve the above-mentioned technical deficiencies. The present invention initially analyzes from the perspective of the front-end pretreatment of the PCB chemical nickel-gold production line to determine whether the pre-treatment of the PCB in the early stage is normal, so as to adjust and manage the PCB pre-treatment based on the feedback information, so as to reduce the interference of the front-end pre-treatment on the plating quality of the PCB surface in the later stage. And based on the stability of the front-end pre-treatment, the plating quality of the PCB surface is analyzed to intuitively understand whether the PCB after plating is qualified, so as to ensure the production efficiency of the PCB chemical nickel-gold production line. And in-depth analysis is carried out from two perspectives of qualified processing and unqualified processing. On the one hand, the plating quality of the PCB surface is further determined, and on the other hand, it is judged whether the unqualified plating of the PCB is caused by the operation and plating solution parameters not meeting the requirements, so as to reduce the interference of the operation and plating solution parameters on the plating quality of the PCB.

[0006] The purpose of the present invention can be achieved by the following technical solutions: A process monitoring and control system for a PCB chemical nickel-gold production line includes a production line monitoring and control center, a front-end processing unit, a plating analysis unit, a uniformity analysis unit, a defect interference unit, and a warning end;

[0007] The production line monitoring and control center is used to retrieve the appearance feature images of the PCBs, and send the appearance feature images to the front-end processing unit for preprocessing defect tracking analysis. The obtained preprocessing defect index is judged to obtain a stable signal or a management signal. When a stable signal is generated, the plating analysis unit is used to perform plating quality evaluation and analysis on the collected plating thickness data to obtain a qualified signal or a defect signal;

[0008] When a qualified signal is generated, the uniformity analysis unit is used to perform surface reflection uniformity evaluation and analysis on the collected reflected light intensity, judge the number of rough areas obtained, and obtain a flat signal or a burr signal. When a defect signal is generated, the defect interference unit is used to perform defect interference evaluation and feedback analysis on the collected operation data of the PCB electroless nickel immersion gold production line to obtain a normal signal or an interference signal.

[0009] Preferably, the preprocessing defect tracking analysis process is as follows:

[0010] Collect the processing time period of the PCB electroless nickel immersion gold production line and set it as the time threshold, and obtain the preprocessing items of the PCBs in the PCB electroless nickel immersion gold production line within the time threshold;

[0011] Obtain the appearance feature images of the PCBs after passing through the preprocessing items within the time threshold, and then perform grayscale processing on the appearance feature images corresponding to the defect blocks, obtain the gray values corresponding to each pixel point in each defect block, and compare and analyze the gray values. If the difference between the gray value and the preset gray value threshold exceeds the preset threshold, it is determined that the corresponding pixel point is an abnormal pixel point, obtain the number of abnormal pixel points in each sub-region block, and then obtain the total number of abnormal pixel points, and judge the total number of abnormal pixel points to obtain a preprocessing qualified signal or a preprocessing defect signal.

[0012] Preferably, obtain the ratio between the number corresponding to the generated preprocessing defect signal and the total number of defect blocks, and set it as the preprocessing defect index, and judge the preprocessing defect index: if the preprocessing defect index is less than the preset preprocessing defect index threshold, generate a stable signal; if the preprocessing defect index is greater than or equal to the preset preprocessing defect index threshold, generate a management signal.

[0013] Preferably, the process of evaluating and analyzing the coating quality is as follows: Obtain the PCB after coating processing in the PCB electroless nickel immersion gold production line within the time threshold, and set it as the analysis object. Obtain the area corresponding to the coating in the analysis object, divide the area corresponding to the coating in the analysis object into g sub-region blocks, where g is a natural number greater than zero. Obtain the coating thickness data of each sub-region block. The coating thickness data includes the maximum coating thickness and the minimum coating thickness. Based on the maximum coating thickness and the minimum coating thickness, construct the coating thickness interval Ag, and compare and analyze the coating thickness interval Ag with the preset coating thickness intervals one by one to obtain normal blocks and defective blocks.

[0014] Preferably, obtain the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks, and perform discrimination processing on the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks: If the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks is equal to zero, generate a qualified signal; if the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks is not equal to zero, generate a defective signal.

[0015] Preferably, the process of evaluating and analyzing the surface reflection uniformity is as follows: Based on the laser scanning technology, scan the surface of the coating of each sub-region block in the analysis object point by point or line by line, record the reflected light intensity, and then obtain the standard deviation of the reflected light intensity of all pixels of each sub-region block based on the recorded reflected light intensity, and perform discrimination processing on the standard deviation of the reflected light intensity. If the standard deviation of the reflected light intensity is greater than the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uneven, and the corresponding sub-region is set as a rough region; if the standard deviation of the reflected light intensity is less than or equal to the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uniform, and the corresponding sub-region is set as a uniform region. Obtain the number of rough regions, and perform discrimination processing on the number of rough regions to obtain a flat signal or a burr signal.

[0016] Preferably, the process of evaluating and analyzing the defect interference feedback is as follows: Obtain the operation data of the PCB electroless nickel immersion gold production line within the time threshold. The operation data includes the coating processing index and the qualification rate of the plating solution parameters, and perform discrimination processing on the coating processing index and the qualification rate of the plating solution parameters to obtain a normal signal or an interference signal.

[0017] Preferably, the coating processing index represents the number of times the contact duration of the plating solution corresponding to the nickel plating and gold plating operations of the PCB belongs to the preset contact duration threshold of the plating solution. The contact duration of the plating solution represents the duration from the moment when the PCB starts to contact the plating solution in the plating tank to the moment when the PCB is completely separated from the plating solution. The qualification rate of the plating solution parameters represents the number of qualified plating tank information corresponding to the nickel plating and gold plating of the PCB. Qualified plating tank information means that the values of the plating solution data in the plating tank all belong to the preset range. The plating solution data includes the plating solution temperature and the chemical concentration of the plating solution.

[0018] The beneficial effects of the present invention are as follows:

[0019] (1) The present invention initially analyzes from the perspective of the front-end pretreatment of the PCB chemical nickel-gold production line to determine whether the pre-treatment of the PCB in the early stage is normal, so as to adjust and manage the PCB pretreatment based on the feedback information, reduce the interference of the front-end pretreatment on the quality of the later plating on the PCB surface, and analyze the quality of the plating on the PCB surface under the stable front-end pretreatment, so as to intuitively understand whether the PCB after plating processing is qualified and ensure the production efficiency of the PCB chemical nickel-gold production line;

[0020] (2) The present invention conducts in-depth analysis from two perspectives of qualified processing and unqualified processing, that is, conducts surface reflection uniformity evaluation and analysis from the perspective of qualified processing to intuitively understand the surface reflection uniformity of the plating on the PCB after nickel plating processing, and further determine the quality of the plating on the PCB surface. Conduct defect interference evaluation and feedback analysis from the perspective of unqualified processing, that is, conduct plating quality interference analysis from two points of operation and plating solution parameters to determine whether the unqualified PCB plating is caused by the operation and plating solution parameters not meeting the requirements, so as to conduct targeted management from two perspectives of operation and plating solution parameters to reduce the interference of operation and plating solution parameters on the quality of the PCB plating. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings;

[0022] Figure 1 is the system flow block diagram of the present invention;

[0023] Figure 2 is the method reference diagram of the third embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments;

[0026] Embodiment 1:

[0027] Please refer to Figures 1 to 2 As shown, the present invention is a process monitoring and control system for a PCB chemical nickel-gold production line, including a production line monitoring and control center, a front-end processing unit, a plating layer analysis unit, a uniformity analysis unit, a defect interference unit, and an early warning terminal. The production line monitoring and control center is unidirectionally communicatively connected to the front-end processing unit. The front-end processing unit is unidirectionally communicatively connected to both the plating layer analysis unit and the early warning terminal. The plating layer analysis unit is unidirectionally communicatively connected to both the defect interference unit and the early warning terminal. Both the uniformity analysis unit and the defect interference unit are unidirectionally communicatively connected to the early warning terminal;

[0028] The production line monitoring and control center is used to retrieve the appearance feature image of the PCB and send the appearance feature image to the front-end processing unit for preprocessing defect tracking analysis, so as to intuitively understand whether the previous PCB preprocessing is normal. The specific preprocessing defect tracking analysis process is as follows:

[0029] Collect the processing time period of the PCB chemical nickel-gold production line and set it as the time threshold;

[0030] Obtain the preprocessing items of the PCB in the PCB chemical nickel-gold production line within the time threshold. The preprocessing items include steps such as degreasing, micro-etching, and pickling;

[0031] Obtain the appearance feature image of the PCB after passing through the preprocessing items within the time threshold, and then perform grayscale processing on the appearance feature image corresponding to the defect block to obtain the grayscale values corresponding to each pixel point in each defect block, and compare and analyze the grayscale values. If the difference between the grayscale value and the preset grayscale value threshold exceeds the preset threshold, it is determined that the corresponding pixel point is an abnormal pixel point. Obtain the number of abnormal pixel points in each sub-region block, and then obtain the total number of abnormal pixel points, and perform discrimination processing on the total number of abnormal pixel points:

[0032] If the total number of abnormal pixel points is less than the preset threshold, a preprocessing qualified signal is generated;

[0033] If the total number of abnormal pixel points is greater than or equal to the preset threshold, a preprocessing defect signal is generated. Obtain the ratio between the number corresponding to the generated preprocessing defect signal and the total number of defect blocks, and set it as the preprocessing defect index, and perform discrimination processing on the preprocessing defect index:

[0034] If the preprocessing defect index is less than the preset preprocessing defect index threshold, a stable signal is generated;

[0035] If the pre - treatment defect index is greater than or equal to the preset pre - treatment defect index threshold, a management signal is generated, and the stable signal or the management signal is sent to the warning end. After receiving the stable signal or the management signal, the warning end immediately displays the preset warning text corresponding to the stable signal or the management signal. The preset warning text corresponding to the stable signal is: Pre - treatment is stable, and the preset warning text corresponding to the management signal is: Pre - treatment defect, so as to intuitively understand whether the pre - treatment of the PCB interferes with the subsequent plating quality, and adjust the pre - treatment of the PCB to improve the pre - treatment effect of the PCB;

[0036] When a stable signal is generated, the plating analysis unit is used to perform plating quality evaluation and analysis on the collected plating thickness data, so as to intuitively understand whether the PCB after plating processing is qualified, and ensure the production efficiency of the PCB electroless nickel - gold production line. The specific plating quality evaluation and analysis process is as follows:

[0037] Obtain the PCB after plating processing in the PCB electroless nickel - gold production line within the time threshold, and set it as the analysis object. Obtain the area corresponding to the plating in the analysis object, divide the area corresponding to the plating in the analysis object into g sub - area blocks, where g is a natural number greater than zero. Obtain the plating thickness data of each sub - area block. The plating thickness data includes the maximum plating thickness and the minimum plating thickness. Based on the maximum plating thickness and the minimum plating thickness, construct the plating thickness interval Ag, and compare and analyze the plating thickness interval Ag with the preset plating thickness interval one by one:

[0038] If the plating thickness interval Ag is included in the preset plating thickness interval, it is determined that the corresponding sub - area block is a normal block; if the plating thickness interval Ag is not included in the preset plating thickness interval, it is determined that the corresponding sub - area block is a defective block;

[0039] Obtain the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks, and perform discriminant processing on the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks:

[0040] If the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks is equal to zero, a qualified signal is generated;

[0041] If the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks is not equal to zero, a defective signal is generated. The qualified signal or the defective signal is sent to the warning end. After receiving the qualified signal or the defective signal, the warning end immediately displays the preset warning text corresponding to the qualified signal or the defective signal, so as to intuitively understand whether the PCB after plating processing is qualified, and ensure the production efficiency of the PCB electroless nickel - gold production line.

[0042] Embodiment 2:

[0043] When a qualified signal is generated, the uniformity analysis unit is used to evaluate and analyze the surface reflection light intensity of the collected reflected light, so as to intuitively understand the reflection light uniformity of the PCB surface coating after nickel plating, and at the same time facilitate the targeted management of the PCB electroless nickel immersion gold production line to improve the quality of the PCB coating. The specific process of the surface reflection light uniformity evaluation and analysis is as follows:

[0044] Based on the laser scanning technology, each sub-region block coating surface in the analysis object is scanned point by point or line by line, the reflected light intensity is recorded, and then the standard deviation of the reflected light intensity of all pixels in each sub-region block is obtained based on the recorded reflected light intensity. The standard deviation of the reflected light intensity is judged. If the standard deviation of the reflected light intensity is greater than the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uneven, and the corresponding sub-region is set as a rough region. If the standard deviation of the reflected light intensity is less than or equal to the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uniform, and the corresponding sub-region is set as a uniform region;

[0045] The number of rough regions is obtained, and the number of rough regions is judged: if the number of rough regions is equal to zero, a flat signal is generated; if the number of rough regions is not equal to zero, a burr signal is generated, and the flat signal or the burr signal is sent to the warning end. After receiving the flat signal or the burr signal, the warning end immediately displays the preset warning text corresponding to the flat signal or the burr signal. The preset warning text corresponding to the flat signal is: the coating reflection is uniform, and the preset warning text corresponding to the burr signal is: the coating reflection is uneven, so as to intuitively understand the reflection light uniformity of the PCB surface coating after nickel plating, and at the same time facilitate the targeted management of the PCB electroless nickel immersion gold production line to improve the quality of the PCB coating;

[0046] When a defect signal is generated, the defect interference unit is used to perform defect interference evaluation and feedback analysis on the operation data of the PCB electroless nickel immersion gold production line, that is, to perform coating quality interference analysis from two points of operation and plating solution parameters, so as to judge whether the unqualified PCB coating is caused by the operation and plating solution parameters not meeting the requirements. The specific process of the defect interference evaluation and feedback analysis is as follows:

[0047] The operation data of the PCB electroless nickel immersion gold production line within the time threshold is obtained. The operation data includes the coating processing index and the qualified rate of the plating solution parameters, that is, to perform coating quality interference analysis from two points of operation and plating solution parameters, so as to judge whether the unqualified PCB coating is caused by the operation and plating solution parameters not meeting the requirements, so as to perform targeted management from two angles of operation and plating solution parameters to reduce the interference of the operation and plating solution parameters on the PCB coating quality;

[0048] Among them, the plating process index represents the number of times the contact duration of the plating solution corresponding to the nickel plating and gold plating operations of the PCB belongs to the preset plating solution contact duration threshold, and the contact duration of the plating solution represents the duration between the moment when the PCB starts to contact the plating solution in the plating tank and the moment when the PCB is completely separated from the plating solution;

[0049] The qualified rate of plating solution parameters represents the number of qualified plating tank information corresponding to nickel plating and gold plating of the PCB. Qualified plating tank information means that the values corresponding to the plating solution data in the plating tank all belong to the preset range, and the plating solution data includes plating solution temperature, plating solution chemical concentration, etc.;

[0050] Perform discrimination processing on the plating process index and the qualified rate of plating solution parameters:

[0051] If the plating process index is equal to 2 and the qualified rate of plating solution parameters is equal to 2, a normal signal is generated;

[0052] If the plating process index is not equal to 2, or the qualified rate of plating solution parameters is not equal to 2, an interference signal is generated. The normal signal or the interference signal is sent to the warning end. After receiving the normal signal or the interference signal, the warning end immediately displays the preset warning text corresponding to the normal signal or the interference signal. The preset warning text corresponding to the normal signal is: Normal state, and the preset warning text corresponding to the interference signal is: Interference, so as to intuitively understand whether the unqualified nickel plating of the PCB is caused by non-compliance of operations and plating solution parameters, so as to conduct targeted management from two perspectives of operations and plating solution parameters to reduce the interference of operations and plating solution parameters on the quality of the PCB plating.

[0053] Example 3:

[0054] A process monitoring and control method for a PCB electroless nickel gold production line includes the following steps:

[0055] Step 1: The preprocessing risk assessment process of the PCB electroless nickel gold production line, that is, perform preprocessing defect tracking analysis on the appearance feature image of the PCB, perform discrimination processing on the obtained preprocessing defect index. If a stable signal is obtained, go to Step 2; if a management signal is obtained, output feedback;

[0056] Step 2: The plating quality monitoring and feedback processing process based on preprocessing stability, that is, perform plating quality assessment analysis on the collected plating thickness data, perform discrimination processing on the ratio between the number of corresponding defective blocks and the number of corresponding normal blocks. If a qualified signal is obtained, go to Step 3; if a defect signal is obtained, go to Step 5;

[0057] Step 3: The process of dividing the surface plating area of the PCB, that is, perform surface reflection uniformity assessment analysis on the collected reflected light intensity to obtain a rough area and a uniform area;

[0058] Step 4: Based on the evaluation and processing process of the reflectance uniformity under rough areas and uniform areas, that is, to discriminate the number of rough areas, and output and feedback the obtained flat signal or burr signal;

[0059] Step 5: The feedback management process for the interference defects of the PCB surface plating quality, that is, to conduct defect interference evaluation and feedback analysis on the operation data collected from the PCB electroless nickel immersion gold production line, to discriminate the obtained plating processing index and the qualified rate of plating solution parameters, and output and feedback the obtained normal signal or interference signal;

[0060] In summary, the present invention initially analyzes from the perspective of the front-end pretreatment of the PCB electroless nickel immersion gold production line to determine whether the previous PCB pretreatment is normal, so as to adjust and manage the PCB pretreatment based on the feedback information to reduce the interference of the front-end pretreatment on the subsequent plating quality of the PCB surface. And based on the stability of the front-end pretreatment, analyze the plating quality of the PCB surface to intuitively understand whether the PCB after plating is qualified, so as to ensure the production efficiency of the PCB electroless nickel immersion gold production line. And conduct in-depth analysis from two perspectives of qualified processing and unqualified processing. That is, from the perspective of qualified processing, conduct surface reflectance uniformity evaluation and analysis to intuitively understand the reflectance uniformity of the plating on the PCB surface after nickel plating, and further determine the plating quality of the PCB surface. From the perspective of unqualified processing, conduct defect interference evaluation and feedback analysis, that is, conduct plating quality interference analysis from two points of operation and plating solution parameters to determine whether the unqualified PCB plating is caused by the operation and plating solution parameters not meeting the requirements, so as to conduct targeted management from two perspectives of operation and plating solution parameters to reduce the interference of operation and plating solution parameters on the PCB plating quality.

[0061] The setting of the threshold value is for the convenience of comparison. Regarding the size of the threshold value, it depends on the amount of sample data and the number of base values set by those skilled in the art for each group of sample data; as long as it does not affect the proportional relationship between the parameters and the quantified values.

[0062] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A process monitoring and control system for a PCB electroless nickel gold production line, characterized in that, It includes a production line monitoring and control center, a front-end processing unit, a plating analysis unit, a uniformity analysis unit, a defect interference unit, and a warning end; The production line monitoring and control center is used to retrieve the appearance feature image of the PCB, and send the appearance feature image to the front-end processing unit for preprocessing defect tracking analysis. The obtained preprocessing defect index is judged to obtain a stable signal or a management signal. When a stable signal is generated, the plating analysis unit is used to conduct a plating quality evaluation analysis on the collected plating thickness data to obtain a qualified signal or a defect signal; When a qualified signal is generated, the uniformity analysis unit is used to conduct a surface reflection uniformity evaluation analysis on the collected reflected light intensity, judge the number of rough areas obtained, and obtain a flat signal or a burr signal. When a defect signal is generated, the defect interference unit is used to conduct a defect interference evaluation and feedback analysis on the collected operation data of the PCB electroless nickel immersion gold production line to obtain a normal signal or an interference signal.

2. The process monitoring and control system for a PCB electroless nickel immersion gold production line according to claim 1, wherein The process of the preprocessing defect tracking analysis is as follows: Collect the processing period of the PCB electroless nickel immersion gold production line and set it as the time threshold, and obtain the preprocessing items of the PCB in the PCB electroless nickel immersion gold production line within the time threshold; Obtain the appearance feature image of the PCB after passing through the preprocessing items within the time threshold, and then perform grayscale processing on the appearance feature image corresponding to the defect block. Obtain the gray values corresponding to each pixel point in each defect block, and compare and analyze the gray values. If the difference between the gray value and the preset gray value threshold exceeds the preset threshold, it is determined that the corresponding pixel point is an abnormal pixel point. Obtain the number of abnormal pixel points in each sub-region block, and then obtain the total number of abnormal pixel points, and conduct a discrimination process on the total number of abnormal pixel points to obtain a preprocessing qualified signal or a preprocessing defect signal.

3. A process monitoring and control system for a PCB electroless nickel immersion gold production line according to claim 2, characterized in that, Obtain the ratio between the number corresponding to the generated preprocessing defect signal and the total number of defect blocks, and set it as the preprocessing defect index, and conduct a discrimination process on the preprocessing defect index: if the preprocessing defect index is less than the preset preprocessing defect index threshold, a stable signal is generated; If the preprocessing defect index is greater than or equal to the preset preprocessing defect index threshold, a management signal is generated.

4. A process monitoring and control system for a PCB electroless nickel-gold production line according to claim 1, characterized in that, The process of the plating quality evaluation analysis is as follows: Obtain the PCB after plating in the PCB electroless nickel immersion gold production line within the time threshold and set it as the analysis object. Obtain the area corresponding to the plating in the analysis object, divide the area corresponding to the plating in the analysis object into g sub-region blocks, where g is a natural number greater than zero. Obtain the plating thickness data of each sub-region block. The plating thickness data includes the maximum plating thickness and the minimum plating thickness. Based on the maximum plating thickness and the minimum plating thickness, construct a plating thickness interval Ag, and compare and analyze the plating thickness interval Ag with the preset plating thickness intervals one by one to obtain normal blocks and defect blocks.

5. A process monitoring and control system for a PCB electroless nickel and gold production line according to claim 4, characterized in that, Obtain the ratio between the number corresponding to the defective blocks and the number corresponding to the normal blocks, and perform discrimination processing on the ratio between the number corresponding to the defective blocks and the number corresponding to the normal blocks: If the ratio between the number corresponding to the defective blocks and the number corresponding to the normal blocks is equal to zero, generate a qualified signal; if the ratio between the number corresponding to the defective blocks and the number corresponding to the normal blocks is not equal to zero, generate a defect signal.

6. The process monitoring and control system for a PCB electroless nickel immersion gold production line according to claim 1, characterized in that, The process of evaluating and analyzing the surface reflection uniformity is as follows: Based on the laser scanning technology, scan and analyze the surface of the coating of each sub-region block in the analysis object point by point or line by line, record the reflected light intensity, and then obtain the standard deviation of the reflected light intensity of all pixels in each sub-region block based on the recorded reflected light intensity, and perform discrimination processing on the standard deviation of the reflected light intensity. If the standard deviation of the reflected light intensity is greater than the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uneven, and the corresponding sub-region is set as a rough region; if the standard deviation of the reflected light intensity is less than or equal to the preset standard deviation threshold of the reflected light intensity, it is determined that the coating of the corresponding sub-region is uniform, and the corresponding sub-region is set as a uniform region. Obtain the number of rough regions, and perform discrimination processing on the number of rough regions to obtain a flat signal or a burr signal.

7. A process monitoring and control system for a PCB electroless nickel-gold production line according to claim 1, characterized in that, The process of evaluating and analyzing the defect interference feedback is as follows: Obtain the operation data of the PCB electroless nickel immersion gold production line within the time threshold. The operation data includes the plating processing index and the qualified rate of plating solution parameters, and perform discrimination processing on the plating processing index and the qualified rate of plating solution parameters to obtain a normal signal or an interference signal.

8. A process monitoring and control system for a PCB electroless nickel gold production line according to claim 7, characterized in that, The plating processing index represents the number of the contact duration of the plating solution corresponding to the PCB nickel plating and gold plating operations belonging to the preset contact duration threshold of the plating solution. The contact duration of the plating solution represents the duration between the moment when the PCB starts to contact the plating solution in the plating tank and the moment when the PCB is completely separated from the plating solution. The qualified rate of plating solution parameters represents the number of qualified plating tank information corresponding to the PCB nickel plating and gold plating. The qualified plating tank information means that the values of the plating solution data in the plating tank all belong to the preset range. The plating solution data includes the plating solution temperature and the chemical concentration of the plating solution.

9. A method for monitoring and controlling the process of a PCB electroless nickel and gold production line, which is applied to a process monitoring and control system for a PCB electroless nickel and gold production line according to any one of claims 1-8, characterized in that, It includes the following steps: Step 1: The process of preprocessing risk assessment of the PCB electroless nickel immersion gold production line; Step 2: The process of monitoring and feedback processing of the coating quality based on the preprocessing stability; Step 3: The process of dividing the surface coating area of the PCB; Step 4: The process of evaluating the reflection uniformity based on the rough region and the uniform region; Step 5: The process of feedback management of the interference defects of the surface coating quality of the PCB.

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