Circuit board ink screen printing method based on accurate positioning and positioning device

Abstract

The invention relates to the technical field of image recognition, in particular to a circuit board ink screen printing method based on accurate positioning and a positioning device. The method comprises the following steps: acquiring circuit board placement data; detecting the edge and key positioning points of the circuit board based on the circuit board placement data, and adjusting a fine adjustment indexing rotating rod of a jig top plate to obtain accurate alignment data of the circuit board; the jig top plate is subjected to jig locking through the circuit board accurate alignment data, and the circuit board coining fixing position is obtained; a film pressing frame is installed according to the circuit board coining fixing position, and the pressing force of the film pressing frame is monitored in real time through a pressure sensor; and printing ink screen printing PID control is conducted on the scraper based on the pressing force, and printing ink screen printing control data are generated. Through accurate positioning, real-time pressure control, intelligent quality detection and automatic screen plate positioning, the positioning accuracy and pressure control stability of the circuit board ink screen printing process are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of image recognition, and in particular to a circuit board ink screen printing method and a positioning device based on precise positioning. Background Art

[0002] Traditional screen printing methods usually rely on manual or semi-automatic operations, with low positioning accuracy and prone to deviation, thus affecting the overall quality and reliability of circuit boards. Most of the early ink screen printing processes relied on mechanical positioning devices for simple positioning through the cooperation of optical and mechanical sensors. However, this method is limited by mechanical accuracy and equipment stability and cannot meet high-precision requirements. In recent years, with the progress of automation control technology and precise positioning technology, circuit board ink screen printing methods based on precise positioning have emerged. Modern precise positioning technology uses high-resolution cameras, laser sensors, and image processing algorithms to accurately control the position and quality of ink screen printing by detecting marks or positioning holes on the circuit board in real time. This method not only improves the positioning accuracy but also reduces human operation errors and increases production efficiency and yield. However, currently, traditional ink screen printing methods usually rely on manual or semi-automatic equipment for circuit board alignment and positioning, which is prone to positioning deviation, affecting the accuracy of screen printing. At the same time, the pressure control during the ink screen printing process is not precise enough, resulting in unstable printing quality. Summary of the Invention

[0003] Based on this, it is necessary to provide a circuit board ink screen printing method and a positioning device based on precise positioning to solve at least one of the above technical problems.

[0004] To achieve the above object, a circuit board ink screen printing method based on precise positioning, the method includes the following steps: Step S1: Obtain circuit board placement data; detect the edge and key positioning points of the circuit board based on the circuit board placement data, and adjust the fine-tuning indexing lever of the fixture top plate to obtain precise alignment data of the circuit board; lock the fixture of the fixture top plate through the precise alignment data of the circuit board to obtain the printing pressure fixed position of the circuit board; Step S2: Install the pressure film frame according to the printing pressure fixed position of the circuit board, and monitor the pressing force of the pressure film frame in real time through a pressure sensor; perform PID control on the ink screen printing of the squeegee based on the pressing force to generate ink screen printing control data; optimize the local rheological angle of the ink screen printing control data through vision technology to generate scraping optimization data; Step S3: Determine the abnormal drying of the ink layer through the scraping optimization data, and perform visual quality inspection on the ink layer based on the determination result to generate ink screen printing quality inspection data; Step S4: Use the ink screen printing quality detection data to perform identification stencil positioning on the printed and fixed positions of the circuit board, generating identification stencil positioning data; based on the identification stencil positioning data, perform automatic positioning and identification printing on the printed and fixed positions of the circuit board to execute the intelligent circuit board ink screen printing operation.

[0005] Through the detection of the edges and key positioning points of the circuit board, the present invention ensures the precise alignment of the circuit board on the top plate of the jig, greatly reducing the screen printing error, avoiding printing non-conformities caused by position deviations, and ensuring the accuracy of subsequent processes. Adjusting the fine-tuning indexing rod of the top plate of the jig can perform precise fine-tuning according to different circuit board characteristics, enabling each circuit board to be printed at the same position, further ensuring the stability and consistency of production. Through precise alignment and positioning, the waste products caused by the position offset of the circuit board are reduced, effectively improving the yield rate and saving the raw material cost. By using a pressure sensor to monitor the pressing force of the pressure film frame, precise adjustment of the pressing process can be achieved, avoiding problems such as uneven ink distribution and squeegee wear caused by excessive or insufficient pressing force. By using a PID control system to adjust the ink screen printing process of the squeegee in real time, precisely controlling the squeegee speed and pressure, ensuring uniform coating of the ink, and being able to adapt to the changes in the ink characteristics of different batches. Optimizing the scraping angle based on vision technology can more flexibly respond to different graphics or circuit board surface characteristics, improving the rheology of the ink, and further improving the accuracy and uniformity of screen printing. By discriminating the abnormalities during the drying process of the ink layer, problems such as uneven ink drying and incomplete curing can be immediately detected, avoiding printing quality non-compliance caused by incomplete ink curing. Visual quality inspection is performed after the ink layer is completed, which can accurately identify defects in ink screen printing, such as too thick, too thin, or missing printing of the ink, providing data support for subsequent correction. Through the quality inspection data, the system can automatically perform identification stencil positioning on the printed and fixed positions of the circuit board, ensuring that the position of the circuit board is always accurate during the printing process, thereby improving the automation level of the production process. The functions of automatic positioning and identification printing reduce the need for manual adjustment, thereby reducing the risk of human operation errors and improving production efficiency. Therefore, the present invention improves the positioning accuracy and pressure control stability of the circuit board ink screen printing process through precise positioning, real-time pressure control, intelligent quality inspection, and automatic stencil positioning.

[0006] Preferably, step S1 includes the following steps: Step S11: Obtain the circuit board placement data; Step S12: Based on the circuit board placement data, capture the circuit board image through a camera, and perform image preprocessing on the circuit board image to generate a standard circuit board image, where the image preprocessing includes image denoising, image brightness enhancement, and image binarization; Step S13: Extract the circuit board edge of the standard circuit board image, and confirm the edge corner points based on the circuit board edge; connect the edge corner points to obtain edge corner connection points and mark them as key positioning points; Step S14: Perform spatial position fitting adjustment on the fixture top plate according to the key positioning points to obtain accurate circuit board alignment data; Step S15: Lock the fixture top plate through the accurate circuit board alignment data to obtain the circuit board printing and fixing position.

[0007] The present invention ensures the accurate recording of the initial position and state of the circuit board by obtaining the circuit board placement data as the basis for subsequent operations, providing reliable data support for fine alignment. By capturing the circuit board image with a camera and performing image preprocessing, including denoising, brightness enhancement, and binarization, the clarity and contrast of the image are ensured. This processing can effectively remove image noise and improve image quality, thereby providing an accurate basis for subsequent edge extraction and positioning. By extracting the circuit board edge from the standard circuit board image, the geometric shape information of the circuit board can be accurately obtained, which helps to identify the contour of the circuit board and locate key points, providing an accurate geometric reference for subsequent alignment and positioning. Based on the corner points extracted from the circuit board edge, after connection, they are marked as key positioning points, ensuring the accurate docking position between the circuit board and the fixture. The confirmation of these key points lays the foundation for subsequent alignment operations, improving the reliability and consistency of positioning. According to the confirmed key positioning points, perform spatial position fitting adjustment on the fixture top plate to ensure the accurate alignment of the circuit board. Spatial fitting adjustment can finely adjust the relative position between the circuit board and the fixture top plate, thereby eliminating alignment errors and achieving more accurate positioning. By using the accurate circuit board alignment data to lock the fixture top plate, the fixed position of the circuit board during the printing process is ensured, avoiding any change in the position of the circuit board during subsequent operations, thus guaranteeing the accuracy and stability of the screen printing process.

[0008] Preferably, step S14 includes the following steps: Step S141: Perform laser ranging on the circuit board surface according to the key positioning points to generate circuit board key positioning point data; Step S142: Set the theoretical reference point coordinates, and perform coordinate comparison on the circuit board key positioning point data according to the theoretical reference point coordinates to generate circuit board spatial deviation data; Step S143: Perform inverse kinematics calculation on the circuit board spatial deviation data to obtain the fine adjustment parameter data of the fixture top plate; Step S144: Perform fine adjustment indexing rod adjustment on the fixture top plate through the fine adjustment parameter data of the fixture top plate, thereby generating accurate circuit board alignment data.

[0009] Through the laser ranging technology, the present invention can accurately measure the positions of key positioning points on the surface of the circuit board. Laser ranging not only has high precision but also can avoid the errors caused by traditional contact measurements, ensuring the accuracy of the circuit board positioning data. By comparing the key positioning point data of the circuit board with the coordinates of the theoretical reference points, the deviation of the circuit board in space can be quickly detected. This process helps to accurately quantify the spatial error of the circuit board, thereby providing a reliable data basis for subsequent adjustments. Through inverse kinematics calculation of the spatial deviation data of the circuit board, the parameter data for fine-tuning the top plate of the fixture can be generated. The inverse kinematics calculation ensures the scientific nature and efficiency of the adjustment process by accurately solving the adjustment parameters, thereby achieving precise adjustment of the top plate of the fixture. By means of precise adjustment parameters, controlling the fine-tuning indexing lever of the top plate of the fixture enables very fine adjustments. This fine-tuning method minimizes the alignment error of the circuit board, ensures the precise position of the circuit board on the fixture, and avoids subsequent production problems caused by inaccurate alignment. Through automated means such as laser ranging, automatic coordinate comparison, and inverse kinematics calculation, the complexity and errors of manual operations are reduced, and the manual adjustment time is decreased. The fine-tuning indexing lever can complete the adjustment quickly and accurately, significantly improving the production efficiency. Each adjustment is based on precise data and calculations, reducing the deviation caused by improper manual operations and ensuring the consistency and stability in the production process. As a result, the quality and precision of the product are maintained at a high level.

[0010] Preferably, the installation of the laminating frame according to the printing and fixing position of the circuit board in step S2 includes: Set the diameter tolerance of the positioning holes for laminating frame installation according to the printing and fixing position of the circuit board to be ±0.02 mm, the position tolerance to be ±0.05 mm, and control the flatness error of the laminating frame to be ≤0.1 mm and the parallelism error to be ≤0.05 mm. The fixing method uses M2-M4 screws or a clamping pressure method of 5-15 N to install and fix the laminating frame, and a margin of ≥2 mm is reserved.

[0011] The present invention strictly controls the diameter tolerance (±0.02 mm) and position tolerance (±0.05 mm) of the positioning holes of the film pressing frame, ensuring a high-precision fit between the film pressing frame and the printing and fixing position of the circuit board. This can effectively avoid the offset or misalignment of the film pressing frame, thereby ensuring the accurate progress of the subsequent screen printing process and avoiding printing errors caused by offset. Controlling the flatness error of the film pressing frame ≤0.1 mm and the parallelism error ≤0.05 mm ensures uniform contact between the film pressing frame and the surface of the circuit board. Such precision requirements can avoid uneven pressure distribution caused by unevenness or non-parallelism of the film pressing frame, thereby ensuring the quality of ink screen printing and reducing printing defects. The precise installation of the film pressing frame ensures uniform distribution of ink on the surface of the circuit board during the printing process, avoiding ink accumulation or weak areas caused by inaccurate positioning. This precision control contributes to the uniformity of ink screen printing and improves the printing quality. By strictly requiring the positioning hole tolerance, position tolerance, etc., the negative impact of the position deviation of the film pressing frame on the screen printing effect is reduced, ensuring the printing precision and consistency of each circuit board. The film pressing frame is installed using M2-M4 screws or a clamping pressure method of 5-15 N, providing a stable fixing force. This fixing method can avoid displacement or deformation of the film pressing frame due to vibration, temperature change or external force interference, ensuring the stability of the film pressing frame throughout the production process. By reserving a margin of ≥2 mm, damage or deformation to the film pressing frame and the surface of the circuit board caused by over-tightening during the installation process is avoided, ensuring the safety and reliability of the installation process.

[0012] Preferably, the PID control of ink screen printing for the squeegee based on the pressing force in step S2 includes: Judge whether the pressing force is greater than 0. If the pressing force is equal to 0, the height of the squeegee is adjusted by the servo motor until the pressing force is greater than 0; If the pressing force is greater than 0, perform time series analysis on the pressing force to generate a pressing force time series strain curve; calculate the curve slope of the pressing force time series strain curve to obtain the pressing rate data; Perform pressing force correlation analysis on the pressing force time series strain curve through the pressing rate data to obtain pressing force positive correlation data and pressing force negative correlation data; Set the pressing force critical value according to the pressing force positive correlation data and the pressing force negative correlation data, and use the pressing force critical value to perform PID fuzzy control on the squeegee, thereby generating ink screen printing control data.

[0013] The present invention ensures that the squeegee is always in the best working state by judging the pressing force in real time and adjusting the height of the squeegee (when the pressing force is 0, the servo motor adjusts the height until the pressing force is greater than 0). This adjustment method avoids the situation of too low or too high squeegee pressure, ensures the pressure uniformity during the ink screen printing process, and thus improves the printing quality. By performing a timing analysis on the pressing force and generating a pressing force timing strain curve, the trend of pressure change can be monitored and adjusted in real time. This real-time monitoring avoids the unstable influence on the ink flow caused by pressure fluctuations, thereby improving the consistency of the screen printing effect. By calculating the slope of the pressing force timing strain curve, the obtained pressing rate data can more precisely control the movement and pressure change of the squeegee. The optimized pressing rate helps to ensure that the squeegee maintains a uniform pressure distribution throughout the screen printing process, improving the printing quality. Analyzing the positive and negative correlation data of the pressing force on the pressing force timing strain curve can identify the influence on the screen printing quality under different pressing force conditions. By reasonably setting the critical value of the pressing force, the pressure control accuracy during the screen printing process is further improved, ensuring that the ink is evenly coated on the circuit board. Using the critical value of the pressing force to perform PID fuzzy control on the squeegee makes the movement of the squeegee more accurate and flexible. The PID control system adjusts the pressure and movement speed of the squeegee according to real-time feedback, effectively avoiding the negative impact of too large or too small pressure on the printing quality, thereby greatly improving the screen printing accuracy and stability.

[0014] Preferably, the local rheological angle flexible ink scraping optimization of the ink screen printing control data in step S2 includes: Collecting an ink screen printing image set of the ink screen printing control data through machine vision technology, and performing dynamic image screening on the collected ink screen printing image set to obtain an ink screen printing dynamic image set and an ink screen printing static image set; Performing image gray-scale transformation on the ink screen printing dynamic image set to generate an ink screen printing dynamic gray-scale image set; extracting the gray-scale values and image texture features of the ink screen printing dynamic gray-scale image set; analyzing the rheological properties of the ink based on the gray-scale values and image texture features of the ink screen printing dynamic gray-scale image set, so as to obtain ink rheological property data; Using the ink rheological property data to divide the ink screen printing area of the ink screen printing static image set, generating an ink accumulation area and a thin ink area; locally enhancing the pressing force of the pressure film frame based on the ink accumulation area to generate an ink accumulation pressure adjustment area; locally reducing the pressing force of the pressure film frame based on the thin ink area to generate a thin ink pressure adjustment area; Calculate the optimal printing angle for the ink accumulation pressure adjustment area and the thin ink pressure adjustment area to obtain the optimal printing angle for ink screen printing; perform variable-angle flexible control on the ink screen printing control data through the optimal printing angle for ink screen printing to generate scraping ink optimization data, where the angle of variable-angle flexible control is 30° - 75°, and the formula for calculating the optimal printing angle is as follows: ; In the formula, is the optimal printing angle, is the pressure value of the ink accumulation pressure adjustment area, is the pressure value of the thin ink pressure adjustment area, is the relative distance between the ink accumulation pressure adjustment area and the thin ink pressure adjustment area, is the arctangent function.

[0015] The present invention dynamically screens the ink screen printing image set through machine vision technology and divides it into a dynamic image set and a static image set, so as to be able to effectively process different types of images. This processing method can accurately capture the dynamically changing ink flow process, which helps to better adjust the printing parameters and achieve more uniform ink coating. By performing gray-scale transformation on the dynamic image set of ink screen printing, extracting the gray-scale value and image texture features, and deeply analyzing the rheological properties of the ink, it is possible to accurately master the flow and viscosity changes of the ink and ensure the uniformity and stability of the ink in different regions. Based on the ink rheological property data, the static image set of ink screen printing is divided into regions, the ink accumulation region and the thin ink region are identified, and different pressing forces are adjusted for these regions. By increasing the local pressure in the ink accumulation region, the decline in printing quality caused by excessive ink accumulation is avoided; while reducing the pressure in the thin ink region ensures uniform coating of the ink in the thin ink region. This precise control can effectively avoid the phenomena of ink shortage or over-inking in printing and ensure the coating quality of the ink. According to the different characteristics of the ink accumulation region and the thin ink region, local pressure enhancement and reduction are carried out. By optimizing the distribution of the local pressure, the accuracy of scraping ink is further improved, and printing defects caused by uneven pressure during scraping ink are avoided, thereby enhancing the stability of the ink screen printing process and the scraping ink effect. By performing variable-angle flexible control on the ink screen printing control data through the optimal printing angle for ink screen printing, flexible adjustments can be made to the requirements of different regions and different ink characteristics. This flexible control can ensure that the angle adjustment range (30° - 75°) in the scraping ink operation adapts to different ink and material characteristics, thereby improving the adaptability and flexibility of ink screen printing.

[0016] Preferably, the visual quality inspection of the ink layer based on the discrimination result in step S3 includes: Using the discrimination result, the abnormal ink layer is removed from the ink layer to obtain a normal screen printing ink layer; the thickness uniformity of the normal screen printing ink layer is detected by a laser thickness gauge to generate ink layer thickness uniformity data; The visual defects of the normal screen printing ink layer are detected by an industrial camera to generate ink layer visual defect detection data; The ink layer thickness uniformity data and the ink layer visual defect detection data are integrated into ink screen printing quality detection data.

[0017] In the present invention, the abnormal drying of the ink layer is discriminated by using the scraping optimization data, which can effectively identify the abnormal conditions during the drying process of the ink layer. Uneven drying leads to quality problems of the ink layer, such as uneven local thickness or incomplete surface drying of the ink. Through this discrimination step, abnormal ink layers can be detected and removed in advance, preventing defective products from entering the production process and improving the consistency of product quality. Based on the abnormal discrimination result, the unqualified ink layers are removed, ensuring the quality of the final product. The normal screen printing ink layer is detected by a laser thickness gauge, further ensuring the thickness uniformity of the ink layer, avoiding the phenomena of uneven coating or thickness not meeting the standard, thus improving the stability of production. The thickness uniformity of the normal screen printing ink layer is detected by a laser thickness gauge to generate ink layer thickness uniformity data. The high precision and non-contact measurement of the laser thickness gauge can comprehensively monitor the thickness change of the ink layer, detect the uniformity of the ink layer in real time, and ensure that each area of the printing meets the predetermined standard. Through data analysis and comparison, any thickness deviation of the ink layer can be detected in time, preventing quality problems caused by uneven thickness. The visual defects of the normal screen printing ink layer are detected by an industrial camera, which can comprehensively detect the defect conditions on the surface of the ink layer, such as bubbles, cracks, scratches or uneven coating, etc. This detection method can accurately detect tiny defects that are difficult to identify by the naked eye, improving the accuracy and comprehensiveness of defect detection. Through the generated visual defect detection data, each layer of ink can be inspected one by one, further ensuring that the surface quality of the product is flawless. Integrating the ink layer thickness uniformity data and the ink layer visual defect detection data provides comprehensive data support for the ink screen printing quality detection. Through the comprehensive analysis of the two detection data, the ink screen printing quality can be evaluated more comprehensively and accurately, and any potential quality problems can be detected and processed in time. This method significantly improves the quality control accuracy in the ink screen printing process through multi-dimensional and multi-level data analysis.

[0018] Preferably, the abnormal drying discrimination of the ink layer by using the scraping optimization data in step S3 includes: When any of the following situations occurs, it is determined that the drying of the ink layer is abnormal, and the abnormal drying data of the ink layer is obtained: the drying temperature deviates from the optimal range by more than ±10°C, the drying time deviates from the set value by more than ±5 minutes, the thickness of the ink layer deviates from the standard range by ±0.05 mm, the surface of the ink is not completely dry and the adhesion test fails; When the following situations occur simultaneously, it is determined that the drying of the ink layer fails and the failure drying data of the ink layer is obtained: the drying quality inspection fails to meet the standard requirements for 3 consecutive times, the temperature at the outlet of the dryer fluctuates abnormally and the fluctuation duration exceeds 30 minutes, and bubbles or cracks appear on the surface of the ink layer and cannot be restored; When the following situations occur simultaneously, it is determined that there is a drying failure in the ink layer and the drying failure data of the ink layer is obtained: the pressure fluctuation of the squeegee of the ink scraping equipment exceeds ±5%, the qualified rate of the ink layer adhesion test continuously decreases by more than 20%, and the concentration of the ink volatile matter increases abnormally during the drying process and exceeds the preset safety threshold; Integrate the abnormal drying data of the ink layer, the failure drying data of the ink layer, and the drying failure data of the ink layer to obtain the discrimination result.

[0019] The present invention can accurately identify abnormal situations during the drying process of the ink layer by setting multiple judgment criteria (such as drying temperature, drying time, ink layer thickness, etc.). For example, when the drying temperature deviates from the optimal range, the drying time exceeds the set value, the deviation of the ink layer thickness exceeds the standard range, or the surface of the ink is not completely dry, the system can promptly determine that the drying is abnormal and generate abnormal data. This discrimination method can ensure that the drying process meets strict quality standards and avoid ink layer quality problems caused by abnormal drying. By comprehensively considering factors such as drying quality inspection, temperature fluctuation, and the surface quality of the ink layer, it is possible to multi-dimensionally judge whether the ink layer has drying failure. For example, when the drying quality inspection fails 3 consecutive times, the temperature of the dryer fluctuates for more than a certain time, and bubbles or cracks that cannot be restored appear on the surface of the ink layer, the system can determine that the drying fails. This discrimination mechanism improves the early detection ability of drying failure and reduces rework and waste caused by drying failure. By monitoring key parameters such as the pressure fluctuation of the squeegee of the ink scraping equipment, the qualified rate of the ink layer adhesion test, and the concentration of the ink volatile matter during the drying process, it is possible to promptly identify faults in the drying equipment and environment. For example, situations such as excessive pressure fluctuation of the squeegee of the ink scraping equipment, a significant decrease in the qualified rate of the ink layer adhesion, and abnormal increase in the concentration of volatile matter can all be accurately detected and determined as drying failures. Through this mechanism, the normal operation of the equipment and the safety of the drying process can be ensured.

[0020] Preferably, step S4 includes the following steps: Step S41: Use the ink screen printing quality inspection data to perform marking stencil positioning on the printed and pressed fixed positions of the circuit board to generate marking stencil positioning data; Step S42: Based on the positioning data of the identification screen plate, the commonly used positions for fixing the printed circuit board are memorized and stored, generating the commonly used position memory data for ink screen printing. Step S43: According to the commonly used position memory data for ink screen printing, automatic positioning identification printing of the ink screen printing is performed to execute the intelligent ink screen printing operation for the circuit board.

[0021] In the present invention, by using the ink screen printing quality detection data to perform identification screen plate positioning on the printed and pressed fixed positions of the circuit board, the printing positions of the circuit board can be accurately calibrated. The generation of the identification screen plate positioning data ensures that each ink screen printing operation can accurately align with the printing positions of the circuit board, avoiding printing errors and position deviations, and improving the printing accuracy and consistency in the production process. By combining the identification screen plate positioning data with the commonly used position memory storage, the system can quickly identify and store the common ink screen printing positions according to the commonly used position memory data for ink screen printing. Using this memory mechanism, subsequent ink screen printing operations can be automatically positioned without the need for re-positioning and calibration each time, improving the production efficiency and reducing manual intervention. The memory of the commonly used positions enables the system to have an intelligent adaptive ability and can optimize the operation process according to historical data. According to the commonly used position memory data for ink screen printing, the system can automatically position the printing position and perform identification printing, thereby executing the intelligent ink screen printing operation for the circuit board. The automatic positioning process improves the operation efficiency, reduces manual intervention, and reduces the probability of errors. Through intelligent positioning and operation, the accuracy and consistency of the ink screen printing can be ensured, and the quality problems caused by improper manual operation can be reduced. The automatic and intelligent positioning identification printing greatly reduces the operation time and repeated steps in the process. By automatically executing the ink screen printing operation, the production efficiency is improved, and the production process becomes more smooth and efficient. The memory of the commonly used positions enables each operation to be carried out accurately and efficiently, reducing the time waste and material waste caused by positioning errors.

[0022] The present invention provides a positioning device for performing the circuit board ink screen printing method based on precise positioning as described above. The positioning device includes: A position positioning module, configured to obtain the circuit board placement data; detect the edge and key positioning points of the circuit board based on the circuit board placement data, and adjust the fine-tuning indexing rod of the jig top plate to obtain the accurate alignment data of the circuit board; lock the jig top plate through the accurate alignment data of the circuit board to obtain the printed and pressed fixed positions of the circuit board. An ink scraping control module, configured to install the pressure film frame according to the printed and pressed fixed positions of the circuit board, and real-time monitor the pressing force of the pressure film frame through a pressure sensor; perform PID control on the ink scraping blade based on the pressing force to generate ink screen printing control data; optimize the local rheological angle of the ink screen printing control data through vision technology to generate ink scraping optimization data. A quality inspection module is used to determine abnormal drying of the ink layer through scraping ink optimization data, and perform visual quality inspection on the ink layer based on the determination result to generate ink screen printing quality inspection data; A memory storage module is used to identify and position the stencil for the fixed position of the circuit board printing and pressing by using the ink screen printing quality inspection data to generate stencil positioning data; and automatically position and mark the printing for the fixed position of the circuit board printing and pressing based on the stencil positioning data to execute intelligent circuit board ink screen printing operations.

[0023] The beneficial effects of the present invention are as follows: The position positioning module realizes precise alignment of the circuit board by obtaining the circuit board placement data, detecting the edges and key positioning points of the circuit board, and combining the adjustment of the fine-tuning indexing rod. This process locks the fixture on the top plate of the fixture through the circuit board precise alignment data, ensuring the accuracy of the fixed position of the circuit board printing and pressing, avoiding positioning errors, and improving the accuracy of the ink screen printing operation. The scraping ink control module ensures precise adjustment of the scraping ink pressure by real-time monitoring of the pressing force of the pressure film frame and performing PID control on the squeegee for ink screen printing according to the pressing force. Based on this process, the ink screen printing control data can be optimized for local rheological angle flexible scraping ink, further improving the scraping ink effect, ensuring uniform distribution of the ink, and improving the printing quality. The quality inspection module uses the scraping ink optimization data to determine abnormal drying of the ink layer and performs visual quality inspection on the ink layer according to the determination result. This inspection method can effectively detect defects or quality problems in the ink layer, provide a basis for subsequent correction and optimization, and ensure the stability and reliability of the ink screen printing quality. The memory storage module identifies and positions the stencil for the fixed position of the circuit board printing and pressing by using the ink screen printing quality inspection data and generates stencil positioning data. The system can perform automatic positioning and marking printing on the circuit board according to these data to realize intelligent ink screen printing operations, reduce manual intervention, and improve work efficiency and automation level. Therefore, the present invention improves the positioning accuracy and pressure control stability of the circuit board ink screen printing process through precise positioning, real-time pressure control, intelligent quality inspection, and automatic stencil positioning. Description of the Drawings

[0024] Figure 1 It is a schematic diagram of the step flow of a circuit board ink screen printing method based on precise positioning; Figure 2 For Figure 1 the detailed implementation step flow diagram of step S4 in The realization, functional characteristics, and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the drawings. Detailed Embodiments

[0025] The technical method of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0026] In addition, the accompanying drawings are only schematic diagrams of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus the repeated description thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. The functional entities can be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor methods and / or microcontroller methods.

[0027] It should be understood that although terms such as "first" and "second" may be used here to describe various units, these units should not be limited by these terms. These terms are only used to distinguish one unit from another. For example, without departing from the scope of the exemplary embodiments, the first unit can be called the second unit, and similarly the second unit can be called the first unit. The term "and / or" used here includes any and all combinations of one or more of the listed associated items.

[0028] To achieve the above object, please refer to Figures 1 to 2 , a circuit board ink screen printing method based on precise positioning, the method comprising the following steps: Step S1: Obtain the circuit board placement data; detect the circuit board edge and key positioning points based on the circuit board placement data, and adjust the fine-tuning indexing rod of the jig top plate to obtain the precise alignment data of the circuit board; lock the jig on the jig top plate through the precise alignment data of the circuit board to obtain the printing and pressing fixed position of the circuit board; Step S2: Install the pressure film frame according to the printing and pressing fixed position of the circuit board, and monitor the pressing force of the pressure film frame in real time through a pressure sensor; perform PID control on the squeegee for ink screen printing based on the pressing force to generate ink screen printing control data; optimize the local rheological angle flexible ink scraping of the ink screen printing control data through vision technology to generate ink scraping optimization data; Step S3: Determine the abnormal drying of the ink layer through the ink scraping optimization data, and perform visual quality inspection on the ink layer based on the determination result to generate ink screen printing quality inspection data; Step S4: Use the ink screen printing quality detection data to perform identification stencil positioning on the printed and fixed positions of the circuit board to generate identification stencil positioning data; perform automatic positioning and identification printing on the printed and fixed positions of the circuit board based on the identification stencil positioning data to execute the intelligent circuit board ink screen printing operation.

[0029] Through the detection of the edges and key positioning points of the circuit board, the present invention ensures the precise alignment of the circuit board on the top plate of the fixture, greatly reducing the screen printing error, avoiding printing non-conformities caused by position deviations, and ensuring the accuracy of subsequent processes. Adjusting the fine-tuning indexing lever of the top plate of the fixture can perform precise fine-tuning according to different circuit board characteristics, enabling each circuit board to be printed at the same position, further ensuring the stability and consistency of production. Through precise alignment and positioning, the waste products caused by the position deviation of the circuit board are reduced, effectively improving the yield rate and saving the raw material cost. Using the pressure sensor to monitor the pressing force of the pressure film frame can achieve precise adjustment of the pressing process, avoiding problems such as uneven ink distribution and squeegee wear caused by too large or too small pressing force. By using the PID control system to adjust the ink screen printing process of the squeegee in real time, precisely controlling the squeegee speed and pressure, ensuring uniform coating of the ink, and being able to adapt to the changes in the ink characteristics of different batches. Optimizing the scraping angle based on vision technology can more flexibly handle different graphics or circuit board surface characteristics, improve the rheology of the ink, and further improve the accuracy and uniformity of screen printing. By discriminating the abnormalities during the drying process of the ink layer, problems such as uneven ink drying and incomplete curing can be immediately detected, avoiding printing quality non-compliance caused by incomplete ink curing. Performing visual quality inspection after the ink layer is completed can accurately identify the defects of ink screen printing, such as too thick, too thin, or missing printing of the ink, providing data support for subsequent correction. Through the quality detection data, the system can automatically perform identification stencil positioning on the printed and fixed positions of the circuit board, ensuring that the position of the circuit board is always accurate during the printing process, thereby improving the automation level of the production process. The functions of automatic positioning and identification printing reduce the need for manual adjustment, thereby reducing the risk of human operation errors and improving the production efficiency. Therefore, the present invention improves the positioning accuracy and pressure control stability of the circuit board ink screen printing process through precise positioning, real-time pressure control, intelligent quality detection, and automatic stencil positioning.

[0030] In the embodiment of the present invention, refer to Figure 1 As shown, it is a schematic flow chart of the steps of a circuit board ink screen printing method based on precise positioning according to the present invention. In this example, the circuit board ink screen printing method based on precise positioning includes the following steps: Step S1: Obtain the circuit board placement data; detect the circuit board edge and key positioning points based on the circuit board placement data, and adjust the fine-tuning indexing rod of the fixture top plate to obtain the precise alignment data of the circuit board; lock the fixture based on the precise alignment data of the circuit board to obtain the printing and pressing fixed position of the circuit board. In the embodiment of the present invention, the placement data of the circuit board, including its position, angle, edge contour and key positioning point coordinates, is collected by using high-precision sensors (such as machine vision systems, laser rangefinders or capacitive sensors). The data can be transmitted to the control system through an automated production line. Computer vision algorithms or edge detection techniques (such as Canny, Sobel, Hough transform, etc.) are used to identify the circuit board boundary and extract key positioning points (such as fiducial holes, pads or alignment marks). Combining image processing methods (such as template matching, feature point detection), the offset (in the X and Y directions) and rotation angle (θ) of the circuit board are calculated. According to the detected offset, the fine-tuning mechanism (such as a stepper motor, precision lead screw or pneumatic actuator) is driven to adjust the fine-tuning indexing rod of the fixture top plate to achieve high-precision alignment. After the adjustment is completed, the circuit board alignment data is re-collected to ensure that the deviation is within the set tolerance range (such as ±0.01 mm). The detection and adjustment are repeated until the edge and key positioning points of the circuit board completely match the fixture reference position, generating the final precise alignment data, including the final offset compensation value and corrected coordinate information. After confirming the alignment, start the fixture locking mechanism (such as vacuum adsorption, cylinder clamping or electromagnetic clamping) to fix the fixture top plate and keep the circuit board stable. At this time, the printing and pressing position of the circuit board is fixed to ensure the accuracy of subsequent printing or processing.

[0031] Step S2: Install the pressure film frame according to the printing and pressing fixed position of the circuit board, and monitor the pressing force of the pressure film frame in real time through a pressure sensor; perform PID control on the squeegee for ink screen printing based on the pressing force to generate ink screen printing control data; optimize the local rheological angle flexible ink scraping of the ink screen printing control data through vision technology to generate ink scraping optimization data. In the embodiments of the present invention, the fixed position is printed on the circuit board, and the automatic alignment mechanism (such as a guide rail system or a manipulator) is started to accurately install the film pressing frame on the surface of the circuit board. A positioning sensor (such as laser positioning, image recognition) is used to detect the position of the film pressing frame to ensure its precise matching with the silk screen area of the circuit board. A pressure sensor is integrated in the fixing mechanism of the film pressing frame (such as pneumatic clamping, mechanical pressing) to monitor the pressure exerted by the film pressing frame on the circuit board in real time. The pressure data is collected and filtered (such as Kalman filtering, low-pass filtering) to reduce noise and ensure that the pressure is stable within a set range (for example, 10 - 50N). The PID (Proportional-Integral-Derivative) control is combined to adjust the pressing force to prevent the circuit board from deforming due to excessive pressure or affecting the silk screen effect due to insufficient pressure. The actual pressing force deviation is calculated through the pressure sensor data, and the pressure, angle, and speed of the silk screen squeegee are adjusted to optimize the ink silk screen process. Input: Target pressing force vs. Measured pressing force Output: Squeegee angle adjustment Δθ, squeegee pressure adjustment ΔP, squeegee speed adjustment ΔV, control formula: ; where is the current pressure error, , , are the PID control coefficients respectively, is the ink silk screen control adjustment amount, the squeegee parameters are adjusted in real time to generate "ink silk screen control data" for optimizing the silk screen uniformity and ink thickness. A vision detection system (such as a high-resolution industrial camera, optical interference detection) is used to monitor the ink silk screen effect in real time to obtain the local ink rheological characteristics (viscosity, flow rate, coverage rate). Combining with a deep learning model (such as CNN, Transformer) to analyze the rheological behavior of the silk screen area and predict problems such as excessive or insufficient ink thickness or ink spreading. Calculate the dynamic compensation value Δθ' of the squeegee angle and perform adaptive adjustment based on the optimization formula: ; where: θ is the original squeegee angle, and Δθ′ is the flexible adjustment value calculated by the vision detection system. Combining the vision detection results, the final squeegee movement trajectory and angle adjustment value are output to form ink scraping optimization data and fed back to the silk screen system for closed-loop control to ensure printing accuracy and uniformity.

[0032] Step S3: Discriminate the abnormal drying of the ink layer through the ink scraping optimization data, and perform visual quality inspection on the ink layer based on the discrimination result to generate ink silk screen quality inspection data; In the embodiments of the present invention, an infrared thermal imaging sensor and a humidity sensor are used to monitor the temperature field and humidity distribution during the drying process to obtain real-time drying data of the ink layer. Record the key parameters: heating temperature, humidity, drying time, and compare them with the standard set values. Calculate the ink drying rate: ; where is the change in the mass of the ink layer, is the time interval. If the ink drying rate is greater than the maximum ink drying rate, it will cause the ink layer to dry excessively, crack, or the adhesion to decrease. If the ink drying rate is less than the minimum ink drying rate, the ink will not dry, spread, or stick. By combining historical data with a deep learning model (such as LSTM or CNN), the abnormal discrimination threshold is optimized to ensure the stability of the drying process. An industrial camera + multispectral detection (visible light, UV, infrared) is used to collect the surface image of the ink layer after drying. Oblique light illumination and confocal microscopy imaging are used to enhance the contrast of ink defects (such as pinholes, bubbles, cracks). Edge detection (Canny, Sobel) is used to extract the ink contour and calculate the clarity of the screen printing edge. The frequency domain information of the ink layer is analyzed by Fourier transform (FFT) to identify uniformity defects (ripples, stripes). Calculate the ink thickness deviation: , where is the detected ink thickness, is the standard thickness. If the ink thickness deviation value is greater than the maximum ink thickness value, it is determined that the thickness is abnormal. Deep learning (ResNet, YOLO) is used for defect classification (scratches, bubbles, adhesion, ink dropout, etc.). Combining machine learning (SVM, RandomForest) to establish a quality scoring model, generating ink screen printing quality inspection data according to the detection indicators, and returning it to the production system for adjustment or rejection of abnormal products.

[0033] Step S4: Use the ink screen printing quality inspection data to perform identification stencil positioning on the printed and pressed fixed position of the circuit board, generating identification stencil positioning data; based on the identification stencil positioning data, perform automatic positioning and identification printing on the printed and pressed fixed position of the circuit board to execute intelligent circuit board ink screen printing operations.

[0034] In the embodiments of the present invention, high-precision screen printing quality detection points (such as edge sharpness, thickness uniformity) are selected as the positioning reference points for the identification stencil. Coordinate transformation algorithms (ICP iterative closest point matching, RANSAC) are used to calculate the geometric offset of the screen printing area on the circuit board, and identification stencil positioning data is generated, including screen printing accuracy error compensation parameters. The deformation and position offset of the stencil relative to the circuit board are calculated through a vision detection system (CCD + laser rangefinder), and stencil calibration parameters are generated. Machine learning (such as PCA principal component analysis) is used to calculate the optimal stencil fixing area and optimize the screen printing alignment accuracy. A six-degree-of-freedom (6-DOF) robot or a high-precision motion platform is used to adjust the fixed position of the circuit board based on the identification stencil positioning data to ensure screen printing alignment. In combination with a force feedback sensor, the pressing force of the stencil is adjusted to prevent screen printing defects caused by uneven force. Through an automatic screen printer, precise printing is performed according to the identification stencil positioning data, and the following optimizations are carried out: combining scraping ink optimization data, dynamically adjusting the scraper angle to adapt to local screen printing characteristics. A closed-loop feedback system (vision + pressure sensor) is used to adjust the scraper pressure and ink coating thickness in real time. Deep learning (such as YOLOv8) is used to identify screen printing defects (blurring, offset, ink dropout), and correction parameters are calculated. If a screen printing offset is detected, the identification stencil positioning data is adjusted to achieve adaptive optimization.

[0035] Preferably, step S1 includes the following steps: Step S11: Obtain the circuit board placement data; Step S12: Based on the circuit board placement data, capture an image of the circuit board through a camera, and perform image preprocessing on the circuit board image to generate a standard circuit board image, where the image preprocessing includes image denoising, image brightness enhancement, and image binarization; Step S13: Extract the edges of the circuit board from the standard circuit board image, and confirm the edge corner points based on the circuit board edges; connect the edge corner points to obtain edge corner connection points and mark them as key positioning points; Step S14: Perform spatial position fitting adjustment on the top plate of the fixture according to the key positioning points to obtain precise circuit board alignment data; Step S15: Lock the fixture on the top plate of the fixture through the precise circuit board alignment data to obtain the printing and pressing fixed position of the circuit board.

[0036] In the embodiment of the present invention, in step S11, the circuit board placement data is obtained. The circuit board is placed on the fixture bracket by an industrial automation device or manually, and the initial placement data of the circuit board is obtained by using a high-precision sensor (measurement accuracy ±0.01 mm), including the X-Y plane coordinates (error range ±0.02 mm), the rotation angle (accuracy ±0.1°), and the height information (error range ±0.01 mm). In step S12, based on the circuit board placement data, an industrial camera (resolution 1920×1080, frame rate 60 fps) is used to capture the circuit board image and perform image preprocessing. Gaussian filtering (kernel size 3×3) or median filtering (window size 5×5) is used for image denoising; adaptive histogram equalization (contrast limit 2.0, block size 8×8) is used for image brightness enhancement; the Otsu threshold segmentation algorithm is used for image binarization, and the conversion threshold range is [100, 150]. In step S13, the Canny edge detection (low threshold 50, high threshold 150) is used to extract the circuit board edge, and the edge corner points are confirmed based on the Hough transform (line detection threshold 80, minimum line length 50 pixels, maximum gap 10 pixels). After connecting the edge corner points, the edge corner connection points are obtained and marked as key positioning points (at least 4, positioning accuracy ±0.02 mm). In step S14, according to the key positioning points, the spatial position adjustment parameters of the fixture top plate are calculated, including the displacement compensation in the X, Y, and Z directions (maximum offset ±0.05 mm) and the rotation angle compensation (maximum offset ±0.2°). The adjustment is dynamically corrected by using a precision servo motor (step accuracy 0.005 mm) or a pneumatic device (response time ≤50 ms) to generate the accurate alignment data of the circuit board. In step S15, based on the accurate alignment data of the circuit board, the fixture top plate is locked, and the locking methods include mechanical clamping (clamping force 3~5 N), vacuum adsorption (negative pressure -60 kPa), and magnetic fixation (magnetic field strength ≥50 mT). Finally, the printing and fixing position of the circuit board is confirmed to ensure that the fixing error ≤0.02 mm for subsequent process operations.

[0037] Preferably, step S14 includes the following steps: Step S141: Laser ranging is performed on the surface of the circuit board according to the key positioning points to generate the circuit board key positioning point data; Step S142: Set the theoretical reference point coordinates, and compare the coordinates of the circuit board key positioning point data according to the theoretical reference point coordinates to generate the circuit board spatial deviation data; Step S143: Perform inverse kinematics calculation on the circuit board spatial deviation data to obtain the fine-tuning adjustment parameter data of the fixture top plate; Step S144: The fine-tuning indexing rod of the fixture top plate is adjusted by the fine-tuning adjustment parameter data of the fixture top plate, so as to generate the accurate alignment data of the circuit board.

[0038] In the embodiment of the present invention, by performing laser ranging on the surface of the circuit board according to key positioning points, a high-precision laser ranging sensor (ranging accuracy ±0.005 mm) is used to measure the spatial coordinates of the key positioning points of the circuit board, and key positioning point data of the circuit board is generated. In step S142, theoretical reference point coordinates are set (coordinate errors of the X, Y, and Z axes ≤0.01 mm), and coordinate comparison is performed on the key positioning point data of the circuit board, and the spatial deviation of each point is calculated (deviation range ±0.05 mm), so as to generate circuit board spatial deviation data. In step S143, inverse kinematics calculation is performed based on the circuit board spatial deviation data, and a six-degree-of-freedom mathematical model (calculation error ≤0.02 mm) is used to deduce the adjustment angle and displacement amount of the top plate of the fixture, and fine-tuning adjustment parameter data of the top plate of the fixture is generated. In step S144, the top plate of the fixture is adjusted by using the fine-tuning adjustment parameter data of the top plate of the fixture, and the adjustment resolution is 0.005 mm / step, ensuring that the error of the finally generated circuit board alignment data does not exceed ±0.02 mm.

[0039] Preferably, the installation of the film pressing frame according to the printed and fixed position of the circuit board in step S2 includes: Set the diameter tolerance of the positioning hole for the installation of the film pressing frame to be ±0.02 mm and the position tolerance to be ±0.05 mm according to the printed and fixed position of the circuit board, and control the flatness error of the film pressing frame ≤0.1 mm and the parallelism error ≤0.05 mm. The fixing method is to use M2-M4 screws or a fixture pressure method of 5-15 N to install and fix the film pressing frame, and a margin of ≥2 mm is reserved.

[0040] In the embodiment of the present invention, by using a CNC machining equipment to accurately drill holes, ensuring that the diameter tolerance of the positioning holes is ±0.02 mm and the hole position error is controlled within the range of ±0.05 mm, which can ensure that the size and position of the positioning holes meet the requirements for accurately aligning the fixed positions on the circuit board. Use high-precision measuring tools, such as a laser interferometer or a coordinate measuring machine, to check the flatness and parallelism of the film pressing frame. Ensure that the flatness error of the film pressing frame does not exceed 0.1 mm and the parallelism error is controlled within 0.05 mm, thereby ensuring the stability of the frame. Select M2-M4 screws or use a fixture pressure of 5-15 N to fix the film pressing frame. If screws are used for installation, ensure that the screws are tightened evenly to prevent unnecessary displacement; if fixture pressure is used, use an appropriate fixture force to clamp the film pressing frame evenly to ensure stable installation without error. When designing the circuit board and the film pressing frame, ensure that a margin of ≥2 mm is reserved between the circuit board and the frame, which can prevent interference between the film pressing frame and the edges of the circuit board or other components, ensuring sufficient operating space during installation. Through the above steps, the film pressing frame can be accurately installed to ensure that each fixed position on the circuit board meets the design requirements.

[0041] Preferably, the PID control of the squeegee for ink screen printing based on the pressing force in step S2 includes: Determine whether the pressing force is greater than 0. If the pressing force is equal to 0, adjust the height of the squeegee through the servo motor until the pressing force is greater than 0; If the pressing force is greater than 0, perform time series analysis on the pressing force to generate a pressing force time series strain curve; calculate the curve slope of the pressing force time series strain curve to obtain pressing rate data; Conduct a pressing force correlation analysis on the pressing force time series strain curve through the pressing rate data to obtain positive pressing force correlation data and negative pressing force correlation data; Set a pressing force critical value according to the positive pressing force correlation data and the negative pressing force correlation data, and use the pressing force critical value to perform PID fuzzy control on the squeegee, thereby generating ink screen printing control data.

[0042] In the embodiments of the present invention, the contact force between the squeegee and the printed circuit board is monitored in real time by using a pressing force sensor (such as a piezoelectric sensor, a strain gauge sensor, etc.). These sensors can directly feedback the pressing force value and be monitored through a control system. When the detected pressing force is 0, the system will automatically control the servo motor to adjust the height of the squeegee. The movement of the servo motor is precisely adjusted through feedback control to control the distance between the squeegee and the substrate. The adjustment process continues until the pressing force is greater than 0, because a certain contact force between the squeegee and the printed circuit board is required for effective ink transfer during the ink screen printing process. After the pressing force is greater than 0, the system collects the data of the pressing force changing with time in real time and forms a pressing force time series curve, which can be achieved through high-frequency sampling to ensure the real-time and accuracy of the data. Data analysis algorithms are used to process the collected pressing force time series data to extract the trend of the pressing force change. Usually, these data show a curve that gradually increases with time (if the squeegee is gradually pressed), or a fluctuating curve (if the pressing force of the squeegee is adjusted or changed). According to the collected pressing force data, a pressing force time series strain curve is generated, which reflects the dynamic change of the pressing force with time and indicates the response behavior during the squeegee pressing process. Mathematical processing is performed on the pressing force time series strain curve to calculate the slope of the curve. The slope reflects the rate of change of the pressing force. Specifically, the slope can be achieved by solving the derivative of the curve at different time points, that is: slope = change in pressing force ÷ change in time. The calculated slope value represents the rate of change of the pressing force (i.e., the pressing rate). A higher slope value indicates a rapid increase in the pressing force, while a lower slope value indicates a slower change in the pressing force. Through these data, further control of the action response of the squeegee can be performed. The correlation analysis method (such as the Pearson correlation coefficient) is used to perform correlation analysis on the pressing force time series strain curve and other influencing factors (such as ink viscosity, squeegee speed, etc.). This step is used to discover the mutual relationship between the pressing force and other factors. Through analysis, the system will extract the positive correlation data and negative correlation data of the pressing force: the positive correlation data indicates that the pressing force increases with time, reflecting the increasing trend of the pressing force of the squeegee during operation, and the negative correlation data indicates that the pressing force decreases with time, reflecting the weakening trend of the squeegee pressing force.

[0043] Preferably, the local rheological angle flexible ink scraping optimization of the ink screen printing control data in step S2 includes: Collecting an ink screen printing image set of the ink screen printing control data through machine vision technology, and performing dynamic image screening on the collected ink screen printing image set to obtain an ink screen printing dynamic image set and an ink screen printing static image set; Perform image grayscale transformation on the ink screen printing dynamic image set to generate an ink screen printing dynamic grayscale image set; extract the grayscale values and image texture features of the ink screen printing dynamic grayscale image set; analyze the rheological properties of the ink based on the grayscale values and image texture features of the ink screen printing dynamic grayscale image set, so as to obtain ink rheological property data; Use the ink rheological property data to divide the ink screen printing static image set into ink screen printing areas, generating ink accumulation areas and thin ink areas; locally enhance the pressing force of the pressure film frame based on the ink accumulation areas to generate an ink accumulation pressure adjustment area; locally reduce the pressing force of the pressure film frame based on the thin ink areas to generate a thin ink pressure adjustment area; Calculate the optimal printing angle for the ink accumulation pressure adjustment area and the thin ink pressure adjustment area to obtain the optimal ink screen printing angle; perform variable-angle flexible control on the ink screen printing control data through the optimal ink screen printing angle to generate scraping ink optimization data, where the angle of the variable-angle flexible control is 30° - 75°, and the formula for calculating the optimal printing angle is as follows: ; In the formula, is the optimal printing angle, is the pressure value of the ink accumulation pressure adjustment area, is the pressure value of the thin ink pressure adjustment area, is the relative distance between the ink accumulation pressure adjustment area and the thin ink pressure adjustment area, is the arctangent function.

[0044] In the embodiments of the present invention, image acquisition during the ink screen printing process is performed by using a high-resolution camera (such as an industrial camera) and a light source. The machine vision system monitors the ink screen printing process in real time and acquires ink screen printing images at different time points during the printing process. By performing dynamic image screening on the acquired ink screen printing images, invalid images caused by factors such as light, artifacts, or other interference factors are removed. During the screening process, the system determines the ink flow situation and its changes in the images through algorithms to ensure that only valid dynamic images and static images are retained. The ink screen printing dynamic image set contains image data of the ink distribution, flow, and changes during the ink screen printing process, recording the dynamic characteristics of the ink at different time points. The ink screen printing static image set contains image data of the ink distribution in a stationary state after the ink screen printing process ends. Image processing is performed on the ink screen printing dynamic image set, and gray-scale transformation techniques (such as linear or non-linear gray-scale transformation) are applied to convert the color information in the original images into gray-scale information. Texture features in the ink screen printing dynamic image set are extracted through image processing algorithms (such as gray-level co-occurrence matrix or Gabor filtering). The texture features can effectively characterize the distribution pattern and surface characteristics of the ink, including granularity, smoothness, and uniformity, etc. Texture features in the ink screen printing dynamic image set are extracted through image processing algorithms (such as gray-level co-occurrence matrix or Gabor filtering). The texture features can effectively characterize the distribution pattern and surface characteristics of the ink, including granularity, smoothness, and uniformity, etc. Based on the above analysis, rheological characteristic data of the ink are obtained, usually including the viscosity, fluidity, stress-strain relationship, etc. of the ink, and these data provide a basis for subsequent area division and pressure adjustment. The ink screen printing static image set is analyzed by using the ink rheological characteristic data to divide different ink areas. According to the rheological characteristics of the ink, the ink screen printing area is divided into two main areas: The ink accumulation area is the area where more and thicker ink accumulates, which appears due to insufficient squeegee pressure or too high ink concentration. The thin ink area is the area where the ink is thinner and unevenly distributed, which is due to too large squeegee pressure or too low ink viscosity. For the ink accumulation area, the system locally increases the pressing force of the pressure film frame to ensure that the ink in this area can be evenly transferred. The enhanced pressure area will be concentrated in the area where more ink accumulates. For the thin ink area, the system locally reduces the pressing force of the pressure film frame to avoid further dilution or leakage of the ink caused by excessive pressing. The reduced pressure area is located in the part where the ink is thin. During the above pressure adjustment process, the pressure distribution of the pressure film frame is adjusted by controlling a servo motor or a pneumatic control device to generate pressure adjustment areas for the ink accumulation area and the thin ink area. According to the pressure difference and relative position between the ink accumulation pressure adjustment area and the thin ink pressure adjustment area, the optimal printing angle during the ink screen printing process is calculated. The calculation formula for the optimal printing angle is: ; where, is the optimal printing angle, is the pressure value of the ink accumulation pressure adjustment area, is the pressure value of the thin ink pressure adjustment area, is the relative distance between the ink accumulation pressure adjustment area and the thin ink pressure adjustment area, is the arctangent function. By calculating the pressure difference between the ink accumulation area and the thin ink area, the optimal printing angle can optimize the contact angle between the squeegee and the printing substrate. Based on the calculated optimal printing angle, the system adjusts the ink screen printing control data through variable-angle flexible control. Specifically, the angle of the squeegee will vary between 30° and 75°, adapting to the rheological properties of the ink according to the pressure adjustment in different areas. After variable-angle flexible control, the generated optimized squeegee data can ensure that the squeegee adapts to the fluidity of the ink at different angles and optimize the accuracy of the printing process.

[0045] Preferably, the visual quality inspection of the ink layer based on the discrimination result in step S3 includes: Using the discrimination result to remove abnormal ink layers from the ink layer to obtain a normal screen-printed ink layer; detecting the thickness uniformity of the normal screen-printed ink layer with a laser thickness gauge to generate ink layer thickness uniformity data; Performing visual defect detection on the normal screen-printed ink layer with an industrial camera to generate ink layer visual defect detection data; Integrating the ink layer thickness uniformity data and the ink layer visual defect detection data into ink screen printing quality inspection data.

[0046] In the embodiments of the present invention, after optimizing the control of the ink screen printing process, the drying state of the ink layer is analyzed by using the optimized data of ink scraping. The optimized data of ink scraping provides information such as the thickness, distribution, and squeegee angle of the ink layer, and these data help to evaluate the drying degree of the ink layer. Using the obtained optimized data of ink scraping and combining parameters such as the drying time, temperature, and environmental humidity of the ink layer, multivariate analysis is carried out to determine whether there are problems such as uneven drying, over-drying, or under-drying of the ink layer. The system adopts a threshold setting method to divide different drying situations and identify abnormal drying areas, such as uneven thickness or surface defects caused by too fast or too slow drying of the ink layer. Finally, through this discrimination method, a discrimination result is obtained, clearly indicating whether there is abnormal drying of the ink layer. According to the discrimination result of step S31, after determining the ink layer with abnormal drying, the system automatically identifies and removes the unqualified ink layer area. For the area with abnormal drying, the system will remove the ink layer in this area by controlling the robotic arm or other automated devices to avoid affecting the subsequent printing quality. The removal operation is generally carried out by means of a squeegee, air flow, or vacuum adsorption. After removing the abnormal area, the remaining part is the normal screen-printed ink layer, which has a uniform thickness and drying state. The thickness of the normal screen-printed ink layer is accurately detected by using a laser thickness gauge. The laser thickness gauge can quickly and non-contact measure the thickness of the ink layer and obtain thickness data through the time difference of laser beam reflection or interference effect. The laser thickness gauge performs multi-point detection to cover the entire normal screen-printed ink layer to ensure thickness uniformity. The detection results are converted into ink layer thickness uniformity data, and these data are used to evaluate the screen printing quality and subsequent optimization measures. The visual inspection of the ink layer is carried out by using an industrial camera combined with a high-resolution light source. The industrial camera captures the surface of the ink layer in real time and captures the fine defects of the ink layer. Through image processing algorithms (such as edge detection, morphological processing, contrast enhancement, etc.), it is analyzed whether there are cracks, bubbles, omissions, color differences, or other surface defects on the surface of the ink layer. The defect classification algorithm is used to classify the detected abnormalities and mark different types of defects (such as cracks, bubbles, etc.). The ink layer thickness uniformity data obtained in step S32 and the ink layer visual defect detection data obtained in step S33 are integrated. The integration method includes aligning the two types of data according to the corresponding ink layer area to ensure that the thickness data and defect data of each area can be matched. Combining these two types of data, the final ink screen printing quality detection data is generated, which includes the overall thickness uniformity of the ink layer and the detailed situation of its surface defects.

[0047] Preferably, the discrimination of abnormal drying of the ink layer by using the optimized data of ink scraping in step S3 includes: When any of the following situations occurs, it is determined that the drying of the ink layer is abnormal, and the abnormal drying data of the ink layer is obtained: the drying temperature deviates from the optimal range by more than ±10°C, the drying time deviates from the set value by more than ±5 minutes, the thickness of the ink layer deviates from the standard range by ±0.05mm, the surface of the ink is not completely dry and the adhesion test fails; When the following situations occur simultaneously, it is determined that the drying of the ink layer fails and the failure drying data of the ink layer is obtained: the drying quality inspection fails to meet the standard requirements for 3 consecutive times, the temperature at the outlet of the dryer fluctuates abnormally and the fluctuation duration exceeds 30 minutes, and bubbles or cracks appear on the surface of the ink layer and cannot recover; When the following situations occur simultaneously, it is determined that there is a drying failure of the ink layer and the drying failure data of the ink layer is obtained: the pressure fluctuation of the squeegee of the ink scraping device exceeds ±5%, the pass rate of the ink layer adhesion test continuously decreases by more than 20%, and the concentration of the ink volatile matter increases abnormally during the drying process and exceeds the preset safety threshold; Integrate the abnormal drying data of the ink layer, the failure drying data of the ink layer, and the drying failure data of the ink layer to obtain the discrimination result.

[0048] In the embodiments of the present invention, the temperature inside the dryer is monitored by a temperature sensor and compared with the set optimal drying temperature range. If the drying temperature deviates from the optimal range by more than ±10°C, it is determined that the drying of the ink layer is abnormal. The set optimal drying temperature range is based on the ink type, thickness, and process requirements. The drying process time is monitored by a timer to ensure that the drying process proceeds according to the preset time. If the drying time deviates from the set value by more than ±5 minutes, it is determined that the drying of the ink layer is abnormal. The thickness of the ink layer is measured in real time using a laser thickness gauge or a contact thickness gauge. If the thickness of the ink layer deviates from the standard range by ±0.05 mm, it is determined that the drying of the ink layer is abnormal. The drying condition of the surface of the ink layer is tested by an adhesion test (such as the tape adhesion method). If the ink surface is not completely dry and the adhesion test fails, it is determined that the drying of the ink layer is abnormal. If any of the above situations occur, it can be determined that the drying of the ink layer is abnormal, and the system automatically records and generates ink layer drying abnormal data. This data includes parameters such as drying temperature, drying time, ink thickness, and surface drying condition. The system detects the quality after each drying, and uses a laser thickness gauge, adhesion test, bubble and crack detection, etc. to inspect the ink layer. If the standard requirements are not met in three consecutive detections, it is determined that the drying of the ink layer fails. The temperature at the dryer outlet is monitored in real time by a temperature sensor. If the temperature fluctuates beyond the preset range and the fluctuation duration exceeds 30 minutes, it is determined that the dryer is operating abnormally, resulting in drying failure. A vision inspection system (such as an industrial camera) is used to inspect the surface defects of the ink layer. If bubbles or cracks appear on the surface and cannot be restored through subsequent repair operations, it is determined that the drying of the ink layer fails. If the above situations occur simultaneously, the system determines that the drying of the ink layer fails and records the ink layer drying failure data, including the number of consecutive unqualified detections, temperature fluctuation information, defect type, and restoration situation. The scraping pressure of the squeegee is monitored in real time by a pressure sensor. If the squeegee pressure fluctuates by more than ±5%, it will cause uneven ink scraping, thus affecting the quality of the ink layer, and then it is determined that there is a drying failure. The system regularly detects the adhesion of the ink layer by an adhesion tester. If the passing rate of the test continuously decreases by more than 20%, it indicates that there is a problem in the drying process, and it is determined that there is a drying failure of the ink layer. The concentration of harmful volatile substances during the drying process is monitored by a volatile substance sensor. If the concentration of ink volatile substances increases abnormally and exceeds the preset safety threshold, it will cause problems during the drying process, and it is determined that there is a drying failure. If the above situations occur simultaneously, the system will automatically determine that there is a drying failure of the ink layer and record the relevant data, including squeegee pressure fluctuation, adhesion decrease ratio, volatile substance concentration change, etc. The system integrates the ink layer drying abnormal data, failure data, and fault data collected in steps S311, S312, and S313 to form a comprehensive discrimination data set. Based on the integrated data, the system uses a determination algorithm (such as the weighted average method or the fuzzy logic method) to evaluate various abnormal, failure, and fault situations and generate the final drying discrimination result.The discrimination result includes whether there is abnormal drying, failure or malfunction of the ink layer, and provides detailed cause analysis data.

[0049] As an example of the present invention, refer to Figure 2 As shown, in this example, the step S4 includes: Step S41: Use the ink screen printing quality detection data to identify the stencil positioning of the printed and pressed fixed position of the circuit board, and generate the stencil positioning data; Step S42: Based on the stencil positioning data, memorize and store the common positions of the printed and pressed fixed position of the circuit board, and generate the ink screen printing common position memory data; Step S43: Perform automatic positioning and marking printing of the ink screen printing according to the ink screen printing common position memory data to execute the intelligent circuit board ink screen printing operation.

[0050] In the embodiments of the present invention, the ink layer quality detection system (such as a laser thickness gauge, a vision detection system, etc.) is used to detect the ink screen printing quality of each batch of circuit boards. Through these devices, data such as the thickness, uniformity, visual defects, and surface quality of the ink layer are obtained. The machine vision system is used to process the images in the ink screen printing quality detection data to identify the specific position of the ink screen printing on the circuit board. Image recognition algorithms (such as edge detection, feature matching, template matching, etc.) are used to accurately identify the printing area of the circuit board. Based on these image data, the printing fixed position on the circuit board is located. According to the results of image processing and the geometric information of the printing position, the identification stencil positioning data is generated, and the printing area position of each circuit board is recorded to ensure that each ink screen printing can be performed at the correct fixed position. Based on the identification stencil positioning data in step S41, the printing fixed position of the circuit board is analyzed, and the commonly used printing positions (such as the edges of the frequently used PCB boards or specific component areas) are selected. The system records the coordinate data of each printing fixed position and the corresponding screen printing image quality characteristics as the standard of the common position. The commonly used printing fixed position data is saved in the database, and a structured data storage method (such as a table, a database, or a cloud storage system) is used to save the coordinates, printing quality, and special requirements (such as ink type, thickness requirements, etc.) of each position. By storing the common positions and their related information in the database, the ink screen printing common position memory data is generated, and these data will become a dynamically updated reference library. As the operation cycle increases, the common position data will be continuously updated and optimized. Before each printing operation starts, the system will automatically call the ink screen printing common position memory data and select the printing position that matches the current circuit board from it. Based on the memory data of the common position, the system will directly locate to the pre-saved printing position, reducing manual intervention. An automatic positioning system (such as a servo motor, a stepper motor, etc.) is used to accurately align the stencil and the circuit board. According to the common position memory data, the positions of the stencil and the circuit board are adjusted to accurately align with the ink screen printing area. Through a closed-loop control system (such as an optical positioning system, a vision feedback mechanism, etc.), it is ensured that the position during the printing process is always accurate, avoiding misalignment or deviation. Once the positioning is completed, the control system will start the ink screen printing equipment (such as a squeegee, a screen printing machine, etc.) to perform the automatic screen printing operation. The equipment will work according to the preset screen printing parameters (such as ink volume, pressure, speed, etc.) to ensure that the ink screen printing of each circuit board meets the quality standards.

[0051] The present invention provides a positioning device for performing the circuit board ink screen printing method based on precise positioning as described above. The positioning device includes: A position positioning module for obtaining circuit board placement data; detecting the edges and key positioning points of the circuit board based on the circuit board placement data, and adjusting the fine-tuning indexing rod of the jig top plate to obtain accurate circuit board alignment data; locking the jig on the jig top plate through the accurate circuit board alignment data to obtain the printing and fixing position of the circuit board. An ink scraping control module for installing a pressure film frame according to the printing and fixing position of the circuit board, and real-time monitoring of the pressing force of the pressure film frame through a pressure sensor; performing PID control on the ink scraping of the squeegee based on the pressing force to generate ink scraping control data; optimizing the local rheological angle flexible ink scraping of the ink scraping control data through vision technology to generate ink scraping optimization data. A quality inspection module for discriminating abnormal drying of the ink layer through the ink scraping optimization data, and performing visual quality inspection on the ink layer based on the discrimination result to generate ink screen printing quality inspection data. A memory storage module for using the ink screen printing quality inspection data to position the marking stencil for the printing and fixing position of the circuit board to generate marking stencil positioning data; automatically positioning and marking the printing for the printing and fixing position of the circuit board based on the marking stencil positioning data to perform intelligent circuit board ink screen printing operations.

[0052] The beneficial effects of the present invention are as follows: The position positioning module realizes the accurate alignment of the circuit board by obtaining the circuit board placement data and detecting the edges and key positioning points of the circuit board, combined with the adjustment of the fine-tuning indexing rod. In this process, the jig on the jig top plate is locked through the accurate circuit board alignment data, ensuring the accuracy of the printing and fixing position of the circuit board, avoiding positioning errors, and improving the accuracy of the ink screen printing operation. The ink scraping control module ensures the accurate adjustment of the ink scraping pressure by real-time monitoring of the pressing force of the pressure film frame and performing PID control on the ink scraping of the squeegee based on the pressing force. Based on this process, the ink scraping control data can be optimized for local rheological angle flexible ink scraping, further improving the ink scraping effect, ensuring uniform ink distribution, and improving the printing quality. The quality inspection module uses the ink scraping optimization data to discriminate abnormal drying of the ink layer and performs visual quality inspection on the ink layer based on the discrimination result. This inspection method can effectively detect defects or quality problems in the ink layer, providing a basis for subsequent correction and optimization, and ensuring the stability and reliability of the ink screen printing quality. The memory storage module positions the marking stencil for the printing and fixing position of the circuit board by using the ink screen printing quality inspection data and generates marking stencil positioning data. The system can perform automatic positioning and marking printing on the circuit board according to these data, realizing intelligent ink screen printing operations, reducing manual intervention, and improving work efficiency and automation level. Therefore, the present invention improves the positioning accuracy and pressure control stability of the circuit board ink screen printing process through precise positioning, real-time pressure control, intelligent quality inspection, and automatic stencil positioning.

[0053] Therefore, in all respects, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the application documents are intended to be encompassed within the present invention.

[0054] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features invented herein.

Claims

1. A circuit board ink screen printing method based on precise positioning, characterized in that: The following steps are involved: Step S1: Obtain circuit board placement data; Based on the circuit board placement data, the edges and key positioning points of the circuit board are detected, and the fine-tuning indexing rod of the jig top plate is adjusted to obtain the precise alignment data of the circuit board; the jig top plate is locked by the precise alignment data of the circuit board to obtain the fixed position of the circuit board printing; Step S2: Install the film pressing frame according to the fixed position of the circuit board printing, and monitor the pressing force of the film pressing frame in real time through the pressure sensor; perform ink screen printing PID control on the scraper based on the pressing force to generate ink screen printing control data; perform local rheological angle flexible scraping optimization on the ink screen printing control data through visual technology to generate scraping optimization data; Step S3: abnormal drying of the ink layer is judged by using the ink scraping optimization data, and visual quality inspection of the ink layer is performed based on the judgment result to generate ink screen printing quality inspection data; Step S4: Use the ink screen printing quality detection data to locate the marking screen at the fixed position of the circuit board printing and generate marking screen positioning data; based on the marking screen positioning data, automatically locate and print the markings at the fixed position of the circuit board printing to perform the intelligent circuit board ink screen printing operation.

2. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: Step S1 includes the following steps: Step S11: obtaining circuit board placement data; Step S12: photographing a circuit board image through a camera based on the circuit board placement data, and performing image preprocessing on the circuit board image to generate a standard circuit board image, wherein the image preprocessing includes image denoising, image brightness enhancement, and image binarization; Step S13: extracting the edge of the circuit board of the standard circuit board image, and confirming the edge corner points based on the edge of the circuit board; connecting the edge corner points to obtain the edge corner connection points and marking them as key positioning points; Step S14: performing spatial position fitting adjustment on the top plate of the fixture according to the key positioning points to obtain accurate alignment data of the circuit board; Step S15: The jig top plate is locked by using the circuit board precise alignment data to obtain a circuit board printing and fixing position.

3. The circuit board ink screen printing method based on precise positioning according to claim 2, characterized in that: Step S14 includes the following steps: Step S141: performing laser ranging on the circuit board surface according to the key positioning points to generate circuit board key positioning point data; Step S142: setting theoretical reference point coordinates, and performing coordinate comparison on key positioning point data of the circuit board according to the theoretical reference point coordinates to generate circuit board space deviation data; Step S143: performing inverse kinematics calculation on the circuit board spatial deviation data to obtain the fixture top plate fine-tuning adjustment parameter data; Step S144: fine-tune the jig top plate and the indexing rod according to the jig top plate fine-tune adjustment parameter data, thereby generating circuit board precise alignment data.

4. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: The step S2 of installing the lamination frame according to the printed circuit board fixed position includes: According to the fixed position of the circuit board printing, the positioning hole diameter tolerance of the lamination frame installation is set to ±0.02mm, the position tolerance is ±0.05mm, and the flatness error of the lamination frame is controlled to be ≤0.1mm and the parallelism error is ≤0.05mm. The lamination frame is installed and fixed using M2-M4 screws or 5-15N clamp pressure, and a margin of ≥2mm is reserved.

5. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: The ink screen printing PID control of the scraper based on the pressing force in step S2 includes: Determine whether the clamping force is greater than 0. If the clamping force is equal to 0, adjust the height of the scraper by the servo motor until the clamping force is greater than 0. If the clamping force is greater than 0, the time series analysis of the clamping force is performed to generate a time series strain curve of the clamping force; the slope of the time series strain curve of the clamping force is calculated to obtain the clamping rate data; The compression force correlation analysis is performed on the compression force time-series strain curve through the compression rate data, and the compression force positive correlation data and the compression force negative correlation data are obtained; The pressing force critical value is set according to the pressing force positive correlation data and the pressing force negative correlation data, and the scraper is controlled by PID fuzzy control using the pressing force critical value, so as to generate ink screen printing control data.

6. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: The step S2 of optimizing the local rheological angle of the ink screen printing control data by visual technology includes: The ink screen printing image set is collected from the ink screen printing control data by using machine vision technology, and the collected ink screen printing image set is dynamically screened to obtain an ink screen printing dynamic image set and an ink screen printing static image set; Performing image grayscale transformation on the ink screen printing dynamic image set to generate the ink screen printing dynamic grayscale image set; extracting the grayscale value and image texture characteristics of the ink screen printing dynamic grayscale image set; analyzing the rheological properties of the ink according to the grayscale value and image texture characteristics of the ink screen printing dynamic grayscale image set, thereby obtaining the ink rheological property data; The ink rheological property data is used to divide the ink screen printing static image set into ink screen printing areas, and the ink accumulation area and the thin ink area are generated; based on the ink accumulation area, the pressing force of the film pressing frame is locally pressure-enhanced to generate the ink accumulation pressure adjustment area; based on the thin ink area, the pressing force of the film pressing frame is locally pressure-reduced to generate the thin ink pressure adjustment area; The optimal printing angle of the ink accumulation pressure adjustment area and the thin ink pressure adjustment area is calculated to obtain the optimal printing angle of the ink screen printing; the ink screen printing control data is flexibly controlled at a variable angle through the optimal printing angle of the ink screen printing to generate ink scraping optimization data, wherein the angle of the variable angle flexible control is 30°~75°, and the formula for calculating the optimal printing angle is as follows: ； In the formula, For the best printing angle, Adjust the pressure value of the ink accumulation pressure area. The pressure value of the thin ink pressure adjustment area, is the relative distance between the ink accumulation pressure adjustment area and the thin ink pressure adjustment area, is the inverse tangent function.

7. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: The visual quality inspection of the ink layer based on the discrimination result in step S3 includes: The abnormal ink layer is removed by using the discrimination result to obtain the normal silk screen ink layer; the thickness uniformity of the normal silk screen ink layer is detected by using a laser thickness gauge to generate the ink layer thickness uniformity data; Use industrial cameras to perform visual defect detection on normal silk-screen ink layers and generate visual defect detection data for the ink layers; Integrate the ink layer thickness uniformity data and ink layer visual defect detection data into ink screen printing quality detection data.

8. The circuit board ink screen printing method based on precise positioning according to claim 7, characterized in that: The abnormal drying judgment of the ink layer by using the ink scraping optimization data in step S3 includes: When any of the following situations occurs, it is determined as abnormal drying of the ink layer and the abnormal drying data of the ink layer is obtained: the drying temperature deviates from the optimal range by more than ±10°C, the drying time deviates from the set value by more than ±5 minutes, the ink layer thickness deviates from the standard range by ±0.05mm, the ink surface is not completely dry and the adhesion test fails; When the following conditions occur at the same time, the ink layer is judged as failed to dry and the ink layer drying failure data is obtained: the drying quality test fails to meet the standard requirements for three consecutive times, the dryer outlet temperature fluctuates abnormally and the fluctuation lasts for more than 30 minutes, bubbles or cracks appear on the surface of the ink layer and cannot be restored; When the following conditions occur at the same time, it is determined to be an ink layer drying failure and the ink layer drying failure data is obtained: the scraper pressure fluctuation of the ink scraping equipment exceeds ±5%, the ink layer adhesion test pass rate continues to drop by more than 20%, and the ink volatiles concentration increases abnormally during the drying process and exceeds the preset safety threshold; The abnormal ink layer drying data, the ink layer drying failure data and the ink layer drying fault data are integrated to obtain the judgment result.

9. The circuit board ink screen printing method based on precise positioning according to claim 1, characterized in that: Step S4 includes the following steps: Step S41: using the ink screen printing quality detection data to perform marking stencil positioning on the printed circuit board fixed position, and generating marking stencil positioning data; Step S42: storing the commonly used position memory of the printed circuit board fixed position based on the identification screen positioning data, and generating the commonly used position memory data of the ink screen printing; Step S43: Perform automatic positioning mark printing of ink silk screen printing according to the commonly used position memory data of ink silk screen printing to execute the ink silk screen printing operation of the intelligent circuit board.

10. A positioning device, characterized in that: Used to perform the circuit board ink screen printing method based on precise positioning as claimed in claim 1, the positioning device comprises: Positioning module, used to obtain circuit board placement data; detect the edge and key positioning points of the circuit board based on the circuit board placement data, and adjust the fine-tuning indexing rod of the fixture top plate to obtain the circuit board precise alignment data; lock the fixture top plate through the circuit board precise alignment data to obtain the circuit board printing fixed position; The ink scraping control module is used to install the film pressing frame according to the fixed position of the circuit board printing and to monitor the pressing force of the film pressing frame in real time through the pressure sensor; to perform ink screen printing PID control on the scraper based on the pressing force to generate ink screen printing control data; to perform flexible ink scraping optimization of the local rheological angle of the ink screen printing control data through visual technology to generate ink scraping optimization data; The quality inspection module is used to judge abnormal drying of the ink layer through ink scraping optimization data, and to perform visual quality inspection of the ink layer based on the judgment result to generate ink screen printing quality inspection data; The memory storage module is used to use the ink silk screen quality inspection data to locate the identification screen at the fixed position of the circuit board printing and generate the identification screen positioning data; based on the identification screen positioning data, the circuit board printing and fixing position is automatically positioned and printed to perform intelligent circuit board ink silk screen printing operations.

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