Aoi In Smt Line And Pcb Production Line

By Author: Shenzhen Ektion Technology Co.Ltd.
Total Articles: 4
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Printed Circuit Boards are expected to work properly according to the specifications of the project. To make sure product quality, PCB manufacturers should institute an assortment of inspection methods during various production procedures.

If the critical flaws are recognized and fixed at an initial stage, the cost can be lessened.

The development of SMT and the miniaturization of electronics components bring growing intricacy of PCB design and a geometric surge in the number of solder joints on a board. Some conventional testing methods like a manual visual inspection can no longer meet the contemporary quality control need. AOI in SMT line is able to detect and process the flaws faced in real-time production. It is now extensively implemented in the assembly and PCB manufacturing process.

What exactly is AOI?

The AOI system lights up the inspected board from different angles and uses high-resolution CCD cameras that automatically scan the board and takes its images. By collating the images captured according to design specifications, it can ...
... assess the quality of the assembled boards and bare boards.

Technically, there are two techniques used in the AOI technology, such as Image Recognition Technique and Design Rule Checking (DRC). As the name suggests, DRC checks the circuits based on the given design needs. For instance, the width of all leads should not be less than 0.127mm. If the tested board is not within that range, the flaws will be highlighted. The Image Recognition method is to collate the digital image stored in the AOI system with captured images of the tested boards. The detection precision of this technique depends on the resolution, the standard image, and the detection programs used. As the PCB design standards and rules are constantly being upgraded, the DRC technique based on design rules is not that applicable. Rather, following the rapid development of high speed image processing and computer technology, the Image Recognition method has turned into mainstream.

Implementation of AOI in SMT line

The initial PCB production has depended on a combination of electrical inspection and manual visual inspection to recognize the flaws on bare boards. Nonetheless, they have inherent drawbacks like low effectiveness, low accuracy, and easily missed detection issues, and so on.

The future of AOI

AOI is an accurate system with strong functions and precise positioning. Implementing AOI in SMT line can conduct a detailed inspection of circuits, component flaws, solder paste printing and other solder joint flaws.

Conclusion

The emergence of AOI owes to people’s pursuit of lighter and thinner electronics products. Though AOI can find out most of the flaws, it has restrictions like being unable to inspect shadowed or hidden connections below BGAs and other packages. As future electronics towards miniaturization, it is important to use AOI and other testing methods together to accomplish the best quality standard.