The introduction of AOI

Automatic Optical Inspection, abbreviated as AOI, uses digital image capture devices (such as CCD cameras) to obtain an inspection image of the object being tested, and uses image comparison methods to identify the differences and shortcomings between the object being tested and the design image (reference image).

 

With the development of electronic manufacturing industry, printed circuit board testing technology is also constantly improving. Automatic Optical Inspection (AOI) technology is the most widely used technology in the field of printed circuit board manufacturing in recent years. AOI technology can detect electrical and physical characteristics on the surface of printed circuit boards, including component packaging, circuit disconnection, short circuits, transition bubbles, and so on. In addition, AOI technology can also detect and correct some manufacturing defects during the manufacturing process, greatly improving the quality and efficiency of printed circuit board production.

 

AOI process

The AOI process typically consists of four steps. The first step is data preparation, which involves inputting customer raw data files into the device for storage. Then there is image acquisition, where the device scans the printed circuit board and uploads the images to the computer. Next is image analysis, where the computer will analyze the uploaded printed circuit board images and extracted data. Operators observe and judge the physical board by comparing the customer's original data with the circuit graphics of the produced physical board, promptly identify defective products and scrap them to avoid them flowing into the next process.

 

 

Picture：Verify

 

Characteristics of AOI

AOI technology has multiple characteristics. Firstly, it is efficiency, as AOI technology can achieve automation and high-speed scanning, greatly shortening the time for printed circuit board detection. Secondly, it has high accuracy. AOI technology can detect very small components and circuits, as well as minor circuit problems. In addition, AOI technology can significantly reduce human factors and avoid problems caused by human errors.

 

Application of AOI

The application of AOI technology is very extensive. For example, it can help factories reduce production costs and avoid losses caused by errors in the production process. In addition, AOI technology can also help electronic enterprises improve product quality and production efficiency, provide customers with high-performance, reliable, and secure products, enhance brand awareness, and thus enhance market competitiveness.

 

Advantages and disadvantages of AOI and manual inspection

Due to the fact that AOI is an optical inspection, any defects that can be detected using AOI can be completely visible to the naked eye. AOI can only be judged based on established standards. If the standards are set too strictly, there will be too many misjudgments. The standard setting is too wide and may miss the inspection. Especially for online AOI, the requirements for composition are higher. But for AOI, after the program is set, the board can be continuously measured, and the machine will not fatigue. For relatively small components, it is difficult to inspect with the naked eye, while AOI has a significant advantage in inspecting smaller components due to its optical amplification function.

 

Visual examination can make flexible judgments based on standards. However, manual inspection is adopted. For boards with a large number of points or batches, long-term inspection can cause fatigue in the human eye, resulting in missed inspections.

 

AOI technology is one of the most widely used technologies in the field of printed circuit board manufacturing. It can help electronic enterprises improve product quality and production efficiency, thereby enhancing market competitiveness. With the continuous development of technology, the application scope and detection effect of AOI technology will also become more mature and perfect.