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AOI inspection process in PCB SMT assembly

date:2022-01-07 17:19:09

Automatic optical inspection is an equipment that detects common defects encountered in welding production based on optical principles. AOI is a new type of test technology that is emerging, but it is developing rapidly, and many manufacturers have introduced AOI test equipment. During automatic detection, the machine automatically scans the PCB through the camera, collects images, compares the tested solder joints with the qualified parameters in the database, after image processing, checks out the defects on the PCB, and displays/marks the defects through the display or automatic signs Come out and be repaired by maintenance personnel. In the PCB SMT assembly process, AOI inspection is essential to the process. AOI is actually an automatic optical detector, which has the functions of automatic inspection, automatic alarm, and abnormal display, and can basically realize automation.

The process of AOI inspection in SMT assembly.

1. Principle Using optical principles, the camera on the device scans the board to collect images, and then the collected solder joint data processed by SMT is compared with the table data in the machine database, and the PCBA soldering status is marked after image processing.

2. Advantages The development direction of most electronic products is moving towards miniaturization, and circuit boards are becoming more and more sophisticated. It is more and more difficult to manually inspect SMT circuit boards, and long-term inspections are easy to produce. Eye fatigue, resulting in missed detection.

In order to improve work efficiency in PCB SMT factories, AOI can reflect its superiority.

The advantages of AOI are as follows:

(1) Save manpower and reduce labor costs;

(2) Increase production efficiency and increase production capacity;

(3) Unified testing standards, no difference due to different line types;

(4) Timely feedback and statistics of production problems;

(5) Collect testing data, provide process analysis, and strengthen process capability;

(6) Improve the yield rate of warehousing products.

3. Location

(1) After the placement machine is used: it can effectively prevent the missing, polarity, displacement, tombstone, reverse, etc. of the components.

(2) Use after reflow soldering: Located at the end of the production line, the inspection system can check the missing, offset and skewed components of the components, the correctness of the solder joints and the lack of tin, solder short-circuit, lifted feet and all polarity aspects defect.



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