Automatic quality inspection and analysis of the h

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Automatic quality inspection and analysis of cigarette packet printing (Part 2)

to solve the problem of process control, the key is to detect the problem in time before the human eye can't distinguish it. From a technical point of view, this goal can be achieved. In order to find the subtle gradual changes in the printing process, the CCD device recording these changes is required to have high accuracy and sensitivity. AVT system is realized by using three array yoccd. It scans the whole printing width step by step through the rapid movement of the camera. Through the previous analysis of printing problems, those process problems will not disappear automatically once they appear. Even if it is a step-by-step scan, it will never let go of those accumulated process problems. However, for random problems, the current visual range of array CCD is limited, and the entire printing width cannot be 100% monitored, which may be missed. To ensure 100% detection of printing defects, a linear CCD camera should be used. The accuracy and sensitivity of linear i~ccd are not as high as that of array ccdn, but it scans the whole printing width in real time through linear scanning, and will never let go of any waste products that have been generated. Table 1 shows the comparison between process control and quality assurance in the period of strategic opportunity that is still in progress

for high-quality printing such as cigarette packet printing, the system combining printing process control and quality assurance is introduced below: a best scheme. The integration scheme of process control and quality assurance AVT has specially developed a product integrating process control and quality assurance - printvisionargus for the special needs of the cigarette packet printing industry. After using Argus, it can significantly reduce printing waste, avoid waste outflow, and improve customer satisfaction. At the same time, with better monitoring means, the starting speed of the printing machine can also be significantly improved, and the efficiency of the equipment can be greatly improved

argus uses two cameras, array CCD and linear CCD respectively. Array CCD camera can monitor various progressive printing process problems at the first time, such as color difference, registration, knife line, etc. When mobile equipment defects are detected, the system will automatically trigger the alarm system. At the same time, the defects found will be framed with boxes of different colors on the screen, and can be easily compared with the standard image stored in the system setting. Each color represents a different type of defect. In this way, even if the operator is a little far away, he can easily identify the type of defect and take measures in time. The front OCCD camera is very sensitive to the change of contrast, and requires a very high energy of the lighting source. This feature enables the array CCD to distinguish extremely subtle image changes. At the same time, the front OCCD camera is also equipped with a high-precision optical lens and an excellent zoom system, which can locally enlarge the image and facilitate judgment. Therefore, it is the best technology for process control. Another group of cameras using linear CCD constantly track all the defects that have occurred in real time, whether it is cumulative process problems or randomly generated problems. Once the system detects defects, the system will mark these defects for the subsequent process to remove, so as to ensure that defective products will not flow into the hands of customers. Argus will also store all detected defects into the built-in SQL database of the system, and can generate quality reports for each job and each paper roll, so as to facilitate internal quality management and communication with customers. Without changing the hardware configuration, we can also focus on some special applications by selecting different software modules, such as 2-dimensional 2-molybdenum sulfide with unique performance. Bar code confirmation - identify the bar code on the machine and classify the bar code quality according to international standards

precise color control -- accurately control the color changes in the printing process. Reflective modules support high reflective materials

the selection of these special modules expands the application field and scope of the system. At present, domestic cigarette packet printing plants pay more and more attention to automatic quality detection, and companies considering the introduction of automatic monitoring system are also increasing. This will be of great help to the stability and improvement of printing quality. When customers choose these systems, they must choose their own quality inspection scheme according to their own equipment and process flow, and suit the remedy to the case

(author/Bai Weimin ivett Co., Ltd. Shanghai Representative Office)

source: printed magazine 2005(6)

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