Combination of AOI and AVI Machines

Alex Fung, Adams Yin
Gardien Group, Hong Kong, Taiwan

In PCB industry, AOI (Automated Optical Inspection) has been grown rapidly in past decades. It is now playing an important role in manufacturing process. Most manufacturers are now using AOI machines to report defects on boards after photo-printing or etching.

On the other hand, AVI (Automated Vision Inspection) which sometimes also called FVI (final vision inspection) is still in early growing stage and not yet widely used in the industry. AOI and AVI machines are both using cameras to visually find defects on PCB. But they are used in different stages of manufacturing process. AOI reports the defects on inner layers or outer layers which have only copper, base and drill holes.

AVI reports the defects on final PCB products which have much more features such as solder mask, gold plate, silk screen. AOI and AVI machines are different kind of machines with different functions, but their working principles are very similar. Many technologies of AVI are built up from AOI. From user point of view, if there is a universal machine which can have the functions of AOI and AVI, then they may save cost, labors and space.

This paper analyses on the combination of AOI and AVI to meet this objective. There are five parts in this paper. The first part focuses on the application of AOI and AVI and identifies all kinds of defects and boards which they can inspect. The second par t compares the hardware and software of AOI and AVI machines. The commons and differences are found out. The third part studies of finding defects under the application and machine issue s of AOI and AVI.

The fourth part is to see the possibilities in combining AOI and AVI. The fifth part is to summarize the key elements that caused the Pros and Cons of the universal machine (or called combined machine).