What Is Automated Optical Inspection? AOI Basics for Minnesota Manufacturers

Those who understand circuit boards know that automated optical inspection is critical to the accurate inspection of electronic assemblies and PCBs. Using automated optical inspection in Minnesota manufacturing facilities is vital to ensuring a quality product.

Why use AOI?

The majority of problems are found in the tiny soldered joints on circuit boards. As boards get smaller and smaller, the allowance for error decreases. Manual inspection is no longer an option. The human eye is incapable of seeing the minuscule defects found on such small joints.

Automated optical inspections Minnesota manufacturing companies keep up with the fast-changing pace of tiny technology. AOIs are ideally placed in the assembly line just after soldering. This placement allows them to catch problems as early as possible.

The basics of AOI

AOI systems uses a scanner to visually capture the board. Several light sources focus on the board, illuminating it for a high-resolution camera. The camera takes photos of the board, creating a composite image.

The AOI then analyzes the photos using several techniques. These methods show whether or not the board has any defects. These techniques include:

  • Template matching: The AOI system compares the board to a “golden” board, or the perfected version
  • Pattern matching: Using stored information about good and bad boards, the AOI system can compare the current image to past boards

These and other methods, such as statistical pattern matching, use a database of previous images to determine whether the board matching the acceptable standard for similar boards.